Patent Application
20240310711
The present application is based on, and claims priority from JP Application Serial Number 2023-043616, filed Mar. 17, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a light source device and a projector.
As a light source device to be used in a projector, there has been proposed a light source device for illuminating a light modulation device such as a liquid crystal panel by temporally scanning the light modulation device with light emitted from a light emitting element.
In JP-A-2007-225956 (Document 1), there is disclosed a projector provided with a light source device including a light source lamp, a liquid crystal light valve, a polygon mirror disposed between the light source device and the liquid crystal light valve, and a projection lens. In this projector, the light source device emits light having an elliptical flux sectional shape. The polygon mirror reflects the light emitted from the light source device to thereby scan an image forming area of the liquid crystal light valve in a short axis direction of the elliptical flux sectional shape.
However, when using the polygon mirror for the scanning with the light as in the projector of Document 1, even when making completely parallel light enter the polygon mirror, the parallelism of the light is impaired by the polygon mirror. Specifically, since the polygon mirror reflects the light while rotating, an incident angle of the light with respect to a reflecting surface of the polygon mirror temporally changes, and the parallel light having entered the polygon mirror turns to light having a predetermined divergence angle to illuminate the liquid crystal light valve. As a result, there is a possibility that a variety of problems related to the image quality of the projector such as degradation of luminance or contrast in the liquid crystal light valve, an occurrence of color unevenness, and a loss of light in the projection lens.
In view of the problems described above, a light source device according to an aspect of the present disclosure includes a first light source configured to emit a first light beam in a first wavelength band, a second light source configured to emit a second light beam in a second wavelength band different from the first wavelength band, a third light source configured to emit a third light beam in a third wavelength band different from the first wavelength band and the second wavelength band, and a transmissive optical part which is formed of a light transmissive member rotatably supported, and which is configured to transmit the first light beam, the second light beam, and the third light beam. The transmissive optical part is made rotatable centering on a rotational axis extending along a first direction crossing an incident direction of the first light beam, an incident direction of the second light beam, and an incident direction of the third light beam. A cross-sectional shape perpendicular to a principal ray of the first light beam emitted from the first light source is a shape having a long axis extending along the first direction. A cross-sectional shape perpendicular to a principal ray of the second light beam emitted from the second light source is a shape having a long axis extending along the first direction. A cross-sectional shape perpendicular to a principal ray of the third light beam emitted from the third light source is a shape having a long axis extending along the first direction. The first light beam enters the transmissive optical part at a first position. The second light beam enters the transmissive optical part at a second position different from the first position. The third light beam enters the transmissive optical part at a third position different from the first position and the second position. In the transmissive optical part, a plane of incidence which the first light beam enters and an exit surface from which the first light beam entering the plane of incidence is emitted are parallel to each other, a plane of incidence which the second light beam enters and an exit surface from which the second light beam entering the plane of incidence is emitted are parallel to each other, and a plane of incidence which the third light beam enters and an exit surface from which the third light beam entering the plane of incidence is emitted are parallel to each other.
A projector according to an aspect of the present disclosure includes the light source device according to one of the aspects of the present disclosure, a light modulation device configured to modulate light including the first light beam, the second light beam, and the third light beam emitted from the transmissive optical part of the light source device based on image information, and a projection optical device configured to project the light modulated by the light modulation device.
A first embodiment of the present disclosure will hereinafter be described using the drawings.
A projector according to the present embodiment is an example of a liquid crystal projector using a liquid crystal panel as a light modulation device.
In the drawings described below, constituents are shown with respective dimensional scale ratios different from each other in some cases in order to make the constituents eye-friendly.
As shown in
The light source device 10 according to the present embodiment is provided with the first light source 11, a second light source 12, the third light source 13, the transmissive optical part 14, a rotary drive device 15, the first reflecting element 17, and the second reflecting element 18.
Hereinafter, in the drawings, the explanation will be presented using an XYZ orthogonal coordinate system as needed. The X axis is an axis parallel to an optical axis AX2 of the second light source 12. The optical axis AX2 of the second light source 12 is defined as an axis extending along a principal ray of a second light beam LG emitted from the second light source 12. The Y axis is an axis perpendicular to the X axis, and is an axis extending along a rotational axis C1 of the transmissive optical part 14. The Z axis is an axis perpendicular to the X axis and the Y axis, and is an axis parallel to an optical axis AX1 of the first light source 11 and an optical axis AX3 of the third light source 13. The optical axis AX1 of the first light source 11 is defined as an axis extending along a principal ray of a first light beam LB emitted from the first light source 11. The optical axis AX3 of the third light source 13 is defined as an axis extending along a principal ray of a third light beam LR emitted from the third light source 13.
The Y-axis direction in the present embodiment corresponds to a first direction in the appended claims. The Z-axis direction in the present embodiment corresponds to a second direction in the appended claims.
As shown in
The optical axis AX1 of the first light source 11 and the optical axis AX3 of the third light source 13 are located on the same axis. The optical axis AX2 of the second light source 12 is perpendicular to the optical axis AX1 of the first light source 11 and the optical axis AX3 of the third light source 13. According to this configuration, when, for example, each of the light sources is provided with a cooling member such as a heatsink, there is no need to obliquely arrange the cooling member, a flow path of cooling air, and so on. Thus, it is possible to increase the degree of freedom of the layout of the components constituting the projector 20, and at the same time, it is possible to achieve a reduction in size of the projector 20.
The light sources 11, 12, and 13 are substantially the same in basic configuration as each other, but the detailed configuration of the second light source 12 is illustrated in
As shown in
The plurality of second light emitting elements 26 is arranged along the Y-axis direction in a row at predetermined intervals. Although the second light source 12 is provided with the five second light emitting elements 26 in the present embodiment, the number of the second light emitting elements 26 is not particularly limited, and it is sufficient for the plurality of second light emitting elements 26 to be arranged in a row along the Y-axis direction.
The substrate 29 supports the plurality of second light emitting elements 26. Although not shown in the drawings, a heatsink for cooling the plurality of second light emitting elements 26 can be disposed on an opposite side to the side at which the plurality of second light emitting elements 26 is disposed out of two principal surfaces of the substrate 29.
As shown in
The plurality of first light emitting elements 25 is arranged in a row at predetermined intervals along the Y-axis direction, namely a direction perpendicular to the sheet of
The third light source 13 is provided with a plurality of third light emitting elements 27 and the substrate 29. The third light emitting elements 27 are each formed of a laser diode for emitting a light beam LR0 in the third wavelength band. Therefore, the light beam LR0 to be emitted from the third light emitting element 27 is linearly polarized light having coherency, and is a laser beam narrow in flux width, and high in parallelism. The third wavelength band is a red wavelength band of, for example, 650 nm±5 nm. In other words, the light beam LR0 to be emitted from the third light emitting element 27 is the red light beam.
The plurality of third light emitting elements 27 is arranged in a row at predetermined intervals along the Y-axis direction, namely a direction perpendicular to the sheet of
As shown in
As shown in
The transmissive optical part 14 transmits each of the blue light beam LB, the green light beam LG, and the red light beam LR emitted from the respective light sources 11, 12, and 13 while rotating centering on the rotational axis C1. Therefore, the side surfaces which the respective colored light beams LB, LG, and LR emitted from the respective light sources 11, 12, and 13 enter are not uniquely fixed, but change according to time. In the transmissive optical part 14, the side surfaces which the respective colored light beams emitted from the respective light sources 11, 12, and 13 enter are referred to as planes of incidence. The side surfaces which emit the respective colored light beams LB, LG, and LR entering the transmissive optical part 14 from the planes of incidence are referred to as exit surfaces. In this case, the plane of incidence and the exit surface change according to time, and are any of pairs of side surfaces parallel to each other out of the four side surfaces 14c1, 14c2, 14c3, and 14c4.
In the present specification, when describing that the two side surfaces of the transmissive optical part 14 are parallel to each other, there is described as “parallel” when an angle between the two side surfaces is within a range of 0±5 degrees taking a processing accuracy of the glass material forming the light transmissive member, an allowable range of the parallelism of the light, and so on into consideration.
As shown in
In the case of the present embodiment, the transmissive optical part 14 has the four side surfaces 14c1, 14c2, 14c3, and 14c4, but the number of the side surfaces is not necessarily required to be four, and is desirably 2×m (m is a natural number no smaller than 2). In other words, it is desirable for the number of the side surfaces to be an even number such as six or eight. When the number of the side surfaces is an even number, each of all of the side surfaces becomes parallel to a side surface opposed to that side surface, and a side surface which does not have a counterpart parallel thereto does not exist. Thus, the occurrence of stray light in the transmissive optical part 14 is little, and thus, it is possible to increase the light use efficiency.
The transmissive optical part 14 can be formed of quartz. In the transmissive optical part 14, as an amount of light transmitted through the light transmissive member increases, an amount of light absorbed by the light transmissive member increases, and a thermal strain occurs in the light transmissive member in some cases. In this case, the polarization directions of the respective colored light beams LB, LG, and LR emitted from the respective light sources 11, 12, and 13 are disturbed, and the linearly polarized light having entered the light transmissive member turns to elliptically-polarized light and is then emitted from the light transmissive member. As a result, in the projector 20, it becomes unachievable to obtain an advantage that it is possible to obtain a predetermined contrast without being provided with an incidence side polarization plate by using a laser diode as each of the light emitting elements. In other words, although the laser diode is used in each of the light emitting elements, there occurs a necessity of using the incidence side polarization plate for uniforming the polarization direction. Therefore, in order to obtain the advantage described above, it is desirable to use the glass material low in Young's modulus and thermal expansion coefficient as the glass material small in thermal strain, and it is desirable to use quartz as an example.
A behavior of the colored light beams LB, LG, and LR when the colored light beams are transmitted through the transmissive optical part 14 will hereinafter be described. It should be noted that the colored light beams LB, LG, and LR are different in incident direction and exit direction from each other, but the behavior is common to the colored light beams LB, LG, and LR. Therefore, here, description will be presented using the green light beam LG emitted from the second light source 12.
In
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
As described above, as long as the plane of incidence and the exit surface of the transmissive optical part 14 are parallel to each other, there is no chance for the proceeding direction of the light beam LG0 to change, and the light beam LG0 is translated in a direction parallel to the optical axis AX2 as time passes irrespective of the rotational angle ω of the transmissive optical part 14. When the rotational angle ω is 0 degree, the displacement d of the light beam LG0 is 0, and when the rotational angle ω is in a range from 0 degree to 45 degrees, the displacement d increases toward either one of the +Z side and the −Z side. At the moment when the rotational angle ω exceeds 45 degrees, the direction of the displacement is reversed while keeping the absolute value of the displacement d, and when the rotational angle ω is in the range from 45 degrees to 90 degrees, the displacement d decreases, and when the rotational angle ω becomes 90 degrees, the displacement d vanishes. The behavior described above is repeated after the rotational angle ω exceeds 90 degrees. Therefore, when the transmissive optical part 14 makes one revolution, the displacement d of the light beam LG0 repeats the cycle described above four times. The displacement of the light beam LG0 can arbitrarily be set by controlling parameters such as the refractive index and the size of the transmissive optical part 14.
The behavior of the light beam is hereinabove described focusing attention only on the light beam LG0 proceeding on the optical axis AX2, but in reality, as shown in
As shown in
The second reflecting element 18 is disposed on a light path of the red light beam LR emitted from the third light source 13, between the third light source 13 and the transmissive optical part 14. The second reflecting element 18 is formed of a dichroic mirror which reflects blue light while transmitting red light. Therefore, the second reflecting element 18 reflects the blue light beam LB emitted from the transmissive optical part 14, and transmits the red light beam LR emitted from the third light source 13. An angle between the second reflecting element 18 and the Z axis is referred to as a tilt angle θ2 of the second reflecting element 18. The tilt angle θ2 of the second reflecting element 18 is larger than 45 degrees.
Since the tilt angle θ2 of the second reflecting element 18 is set larger than 45 degrees, the blue light LB reflected by the second reflecting element 18 proceeds obliquely to the optical axis AX2 so as to come closer to the optical axis AX2. Similarly, since the tilt angle θ1 of the first reflecting element 17 is set larger than 45 degrees, the red light LR reflected by the first reflecting element 17 proceeds obliquely to the optical axis AX2 so as to come closer to the optical axis AX2.
Thus, the blue light beam LB reflected by the second reflecting element 18, the green light beam LG emitted from the transmissive optical part 14, and the red light beam LR reflected by the first reflecting element 17 enter a microlens array 43 in an anterior stage of the light modulation device 21 from respective directions different from each other, and overlap each other on the first microlens array 43 as described later. In the case of the present embodiment, the incident angle of the green light beam LG to the first microlens array 43 is 0 degree. In other words, the green light beam LG perpendicularly enters the first microlens array 43. The incident angle of the blue light beam LB to the first microlens array 43 is α1. The incident angle of the red light beam LR to the first microlens array 43 is α2.
The light modulation device 21 is disposed at the light exit side of the light source device 10 on the optical axis AX2. The light modulation device 21 modulates each of the blue light beam LB, the green light beam LG, and the red light beam LR emitted from the light source device 10 in accordance with image information to form image light. As the light modulation device 21, there is used a transmissive liquid crystal panel. The liquid crystal panel is not provided with a color filter. As a drive system for the liquid crystal panel, there is used a twisted nematic (TN) system, a vertical alignment (VA) system, an in-plane switching (IPS) system, or the like, but the drive system is not particularly limited.
It is desirable to consider an installation position of the light modulation device 21 as follows.
As shown in
As shown in
The first microlens array 43 is disposed at a light incidence side of a first substrate 57 constituting the liquid crystal panel. The first microlens array 43 has a configuration in which a plurality of first microlenses 431 is arranged in a matrix. The first microlens array 43 collects each of the blue light beam, the green light beam, and the red light beam to guide the blue light beam, the green light beam, and the red light beam respectively to the sub-pixels PX1, PX2, and PX3 of the light modulation device 21. Each of the first microlenses 431 is formed of a lenticular lens, and is arranged throughout each of the pixels, namely the three sub-pixels PX1, PX2, and PX3 different in color from each other and arranged in one direction. The lenticular lens is cited as the first microlenses 431 in the present embodiment, but this is not a limitation, and it is possible to adopt microlenses having rectangular lenses arranged in a bricklaying manner, microlenses having lenses arranged so as to correspond to the sub-pixels in a delta arrangement, a microlens array having a honeycomb structure, or the like.
As described above, the blue light beam LB, the green light beam LG, and the red light beam LR enter the first microlenses 431 at respective incident angles different from each other, and therefore, proceed toward respective directions different from each other, and are then converged. Thus, the blue light beam LB enters the blue sub-pixel PX1, the green light beam LG enters the green sub-pixel PX2, and the red light beam LR enters the red sub-pixel PX3. In other words, the first microlens array 43 makes the blue light beam LB emitted from the second reflecting element enter the blue sub-pixel PX1, makes the green light beam LG emitted from the transmissive optical part enter the green sub-pixel PX2, and makes the red light beam LR emitted from the first reflecting element enter the red sub-pixel PX3. The first microlens array 43 in the present embodiment corresponds to a light collecting element in the appended claims.
A second microlens array 44 is disposed at a light exit side of a second substrate 58 constituting the liquid crystal panel. The second microlens array 44 has a configuration in which a plurality of second microlenses 441 is arranged in a matrix. The second microlens array 44 collimates the colored light beams emitted from the liquid crystal panel. The second microlens 441 is disposed for each of the sub-pixels. It should be noted that there is cited an example of performing the collimation of each of the colored light beams after the colored light beam is emitted from the liquid crystal panel in the present embodiment, but it is possible to adopt a configuration in which the second microlens array 44 is arranged at the light incidence side of the liquid crystal panel to perform the collimation of each of the colored light beams before the colored light beam enters the liquid crystal panel instead of this configuration.
As shown in
The projection optical device 23 is constituted by a plurality of lenses. The projection optical device 23 projects the image light having been modulated by the light modulation device 21 toward the projection target surface such as a screen in an enlarged manner. Thus, the image is displayed on the projection target surface.
The light source device 10 according to the present embodiment is provided with the first light source 11 for emitting the blue light beam LB, the second light source 12 for emitting the green light beam LG, the third light source 13 for emitting the red light beam LR, and the transmissive optical part 14 which is formed of the light transmissive member rotatably supported, and which transmits the colored light beams LB, LG, and LR. The transmissive optical part 14 is made rotatable centering on the rotational axis C1 extending along the Y-axis direction. The cross-sectional shape perpendicular to the principal ray of each of the blue light beam LB emitted from the first light source 11, the green light beam LG emitted from the second light source 12, and the red light beam LR emitted from the third light source 13 is the shape having the long axis extending along the Y-axis direction. The blue light beam LB enters the transmissive optical part 14 at the first position P1. The green light beam LG enters the transmissive optical part 14 at the second position P2. The red light beam LR enters the transmissive optical part 14 at the third position P3. In the transmissive optical part 14, the plane of incidence which each of the blue light beam LB, the green light beam LG, and the red light beam LR enters, and the exit surface from which corresponding one of the blue light beam LB, the green light beam LG, and the red light beam LR entering the transmissive optical part 14 from that plane of incidence is emitted are parallel to each other.
The projector 20 according to the present embodiment is provided with the light source device 10, the light modulation device 21 for modulating the blue light beam LB, the green light beam LG, and the red light beam LR emitted from the transmissive optical part 14 of the light source device 10 in accordance with the image information, and the projection optical device 23 for projecting the light modulated by the light modulation device 21.
When using the polygon mirror as a device for performing scanning with light beam as in the related-art light source device, since the polygon mirror reflects the light beam while rotating, the incident angle of the light beam entering the illumination target surface changes from moment to moment with time. Therefore, even when the light beam to be made to enter the polygon mirror is a parallel light beam, the light beam emitted from the polygon mirror becomes a diverging light beam, and therefore, it is extremely difficult to make the light beam always perpendicularly enter the illumination target surface. Therefore, in the related-art projector provided with the polygon mirror, there is a possibility that the degradation of the brightness and the contrast and occurrence of the color unevenness in the light modulation device, a light loss in the projection optical device, and so on occur to degrade the image quality of the projector.
To cope with the problem described above, according to the light source device 10 related to the present embodiment, as shown in
The projector 20 according to the present embodiment is further provided with the first reflecting element 17 for reflecting the red light beam LR emitted from the transmissive optical part 14, the second reflecting element 18 for reflecting the blue light beam LB emitted from the transmissive optical part 14, and the first microlens array 43 which collects each of the blue light beam LB reflected by the second reflecting element 18, the green light beam LG emitted from the transmissive optical part 14, and the red light beam LR reflected by the first reflecting element 17 to guide the colored light beams to the light modulation device 21. The blue light beam LB reflected by the second reflecting element 18, the green light beam LG emitted from the transmissive optical part 14, and the red light beam LR reflected by the first reflecting element 17 enter the first microlens array 43 from respective directions different from each other. The light modulation device 21 has the blue sub-pixels PX1 for modulating the blue light beam LB, the green sub-pixels PX2 for modulating the green light beam LG, and the red sub-pixels PX3 for modulating the red light beam LR. The first microlens array 43 makes the blue light beam LB emitted from the second reflecting element 18 enter the blue sub-pixels PX1, makes the green light beam LG emitted from the transmissive optical part 14 enter the green sub-pixels PX2, and makes the red light beam LR emitted from the first reflecting element 17 enter the red sub-pixels PX3.
The projector 20 according to the present embodiment is provided with three light emitting elements 25, 26, and 27 different in emission color from each other, and due to the layout of the reflecting elements 17, 18 and the operation of the first microlens array 43, it is possible to spatially separate the three colored light beams LB, LG, and LR from each other to make the three colored light beams LB, LG, and LR enter the corresponding sub-pixels PX1, PX2, and PX3. Thus, it is possible to realize the projector 20 capable of displaying a color image without using a color filter in the light modulation device 21. Further, since it is possible to illuminate the light modulation device 21 as a two-dimensional device by performing scanning in the Z-axis direction with the colored light beams LB, LG, and LR each having the long axis in the Y-axis direction, just one transmissive optical part becomes enough, and it is possible to achieve simplification and a reduction is size of the device configuration.
The projector of this kind is designed on the assumption that the incident angle of each of the colored light beams to the first microlens array is always constant. However, when using the polygon mirror as a device for performing scanning with light beam as in the related-art light source device, since the polygon mirror reflects the light beam while rotating, the incident angle of each of the colored light beams entering the first microlens array via corresponding one of the reflecting elements changes with time. In this case, there is a possibility that there occurs a problem that the chromatic purity of the display image is degraded by a specific colored light beam entering an adjacent sub-pixel not corresponding to that colored light beam. Further, there is a possibility that there occurs a problem that the light entering the black matrix of the liquid crystal panel increases to decrease the luminance of the display image.
To cope with the problems described above, according to the projector 20 related to the present embodiment, since each of the colored light beams LB, LG, and LR emitted from the transmissive optical part 14 becomes a substantially parallel light beam, a temporal variation in incident angle of each of the colored light beams LB, LG, and LR to the first microlens array 43 is extremely small. Therefore, since the proportion of the specific colored light beam which enters the adjacent sub-pixel not corresponding to that colored beam of the black matrix decreases, it is possible to prevent the deterioration of the chromatic purity and the luminance of the display image.
Further, even when each of the colored light beams LB, LG, and LR is a laser beam having the coherency, scanning with each of the colored light beams LB, LG, and LR is performed two-dimensionally at high speed on the light modulation device 21, and thus, each of the colored light beams LB, LG, and LR is temporally superimposed. Thus, it is possible to prevent the illuminance unevenness caused by using the light source having the coherency.
Further, according to the present embodiment, it is possible to illuminate a substantially rectangular shape without using an optical system for forming light to have a rectangular shape such as a multi-lens. Therefore, since it is possible to make the whole light path length relatively short, and at the same time, it is possible to reduce the optical components to thereby decrease the number of interfaces between the optical system and the air, and therefore, it is possible to reduce the light loss caused by the interfacial reflection.
Since the light source device 10 according to the present embodiment is a scanning type illumination device, it is possible to put the light emitting elements 25, 26, and 27 off when the colored light beams reach the area where black is intended to be displayed in the light modulation area. Thus, the method of illuminating only the area other than the black display, a so-called area illumination, becomes possible, and it is possible to sufficiently increase the efficiency of the exit light intensity to the input power compared to a conventional non-scanning type illumination method. In association with the above, since the light absorbed by the exit side polarization plate 22 when performing the black display decreases, it is possible to reduce the burden on the exit side polarization plate 22. Thus, it is possible to expect an advantage such as an increase in reliability of the exit side polarization plate 22, or an increase in contrast due to adoption of a polarization plate made of an organic material.
A second embodiment of the present disclosure will hereinafter be described using
A projector according to the present embodiment is substantially the same in basic configuration as that of the first embodiment, but is different in arrangement of some light sources from that of the first embodiment.
In
As shown in
The light source device 40 according to the present embodiment is provided with the first light source 11, the second light source 12, the third light source 13, the transmissive optical part 14, the rotary drive device 15, the first reflecting element 17, and the second reflecting element 18.
In the first embodiment, each of the optical axis AX1 of the first light source 11 and the optical axis AX3 of the third light source 13 is perpendicular to the optical axis AX2 of the second light source 12. In contrast, in the present embodiment, the first light source 11 is arranged at a position where the first light source 11 has rotated counterclockwise from a position where the optical axis AX1 is perpendicular to the optical axis AX2. The third light source 13 is arranged at a position where the third light source 13 has rotated clockwise from a position where the optical axis AX3 is perpendicular to the optical axis AX2.
In the present embodiment, as described above, since the position of the first light source 11 changes from the position in the first embodiment, the first reflecting element 17 is located at a place out of the light path of the blue light beam LB emitted from the first light source 11. In this case, the first reflecting element 17 can be formed of a dichroic mirror which reflects red light and transmits blue light similarly to the first embodiment, or can also be formed of a mirror which reflects light having entered the mirror irrespective of the wavelength band. Further, since the position of the third light source 13 changes from the position in the first embodiment, the second reflecting element 18 is located at a place out of the light path of the red light beam LR emitted from the third light source 13. In this case, the second reflecting element 18 can be formed of a dichroic mirror which reflects blue light and transmits red light similarly to the first embodiment, or can also be formed of a mirror which reflects light having entered the mirror irrespective of the wavelength band.
The tilt angle θ3 of the first reflecting element 17 is larger than 45 degrees, and is smaller than the tilt angle θ1 of the first reflecting element 17 in the first embodiment. The tilt angle θ4 of the second reflecting element 18 is larger than 45 degrees, and is smaller than the tilt angle θ2 of the second reflecting element 18 in the first embodiment.
The rest of the configuration of the projector 30 is substantially the same as in the first embodiment.
In the present embodiment, there can be obtained substantially the same advantages as those of the first embodiment such as an advantage that it is possible to solve the problem of the deterioration of the brightness and the contrast in the light modulation device 21, the occurrence of the color unevenness, the light loss in the projection optical device 23, and the illuminance unevenness caused by using the light source having the coherency, an advantage that it is possible to decrease the number of the interfaces between the optical system and the air, and thus, it is possible to reduce the light loss caused by the interfacial reflection, an advantage that it is possible to increase the light use efficiency without using the optical system for forming the light into a rectangular shape, an advantage that the area illumination becomes possible, and an advantage that it is possible to perform the color display with a simple configuration without using a color filter, and thus, it is possible to prevent the degradation of the chromatic purity and the luminance of the display image.
In the projector of a system in which the colored light beams are assigned to the corresponding sub-pixels by the microlenses arranged in a posterior stage of the light modulation device, in order to improve the quality of the display image, it is important to accurately adjust the incident angles of the respective colored light beams to the microlenses. Further, due to a factor such as a process limitation of the microlenses, it is difficult to freely set the incident angles of the respective colored light beams in some cases. To cope with these problems, in the case of the present embodiment, as described above, since the arrangement of the first light source 11 and the third light source 13 and the tilt angles θ3, 04 of the respective reflecting elements 17, 18 are changed from those in the first embodiment, it is possible to make the incident angle α3 of the blue light beam LB to the first microlens array 43 smaller than the incident angle α1 of the blue light beam LB in the first embodiment. Further, it is possible to make the incident angle α4 of the red light beam LR to the first microlens array 43 smaller than the incident angle α2 of the red light beam LR in the first embodiment. As described above, the configuration of the present embodiment is suitable to when the incident angle of the colored light beam which is made to obliquely enter the first microlens array 43 is intended to be made relatively smaller.
It should be noted that it is possible to decrease the incident angles of the blue light beam LB and the red light beam LR to the first microlens array 43 by making the tilt angles θ1, θ2 of the respective reflecting elements 17, 18 smaller than in the first embodiment, and making the distances between the light modulation device 21 and the respective reflecting elements 17, 18 longer while keeping the layout of the first light source 11 and the third light source 13 the same as in the first embodiment instead of the configuration of the present embodiment. In this case, even when the actual distance from each of the light emitting elements 25, 26, and 27 to the light modulation device 21 becomes longer than the shortest distance which makes the illuminance distribution have a flat shape, it is possible to obtain a top-flat illuminance distribution.
A third embodiment of the present disclosure will hereinafter be described using
A projector according to the present embodiment is substantially the same in basic configuration as that of the first embodiment, but is different in configuration of the light sources from that of the first embodiment.
In
As shown in
The light source device 60 according to the present embodiment is provided with a first light source 61, a second light source 62, a third light source 63, the transmissive optical part 14, the rotary drive device 15, the first reflecting element 17, and the second reflecting element 18.
The second light source 62 is provided with a single second light emitting element 26 and a second flux width adjustment optical system 66. The second flux width adjustment optical system 66 is constituted by a cylindrical concave lens 661 and a cylindrical convex lens 662. The cylindrical concave lens 661 does not have power in the Z-axis direction, but has negative power in the Y-axis direction. The cylindrical convex lens 662 does not have power in the Z-axis direction, but has positive power in the Y-axis direction. Thus, the second flux width adjustment optical system 66 enlarges the flux width in the Y-axis direction of the green light beam LG0 emitted from the second light emitting element 26.
The configuration of each of the first light source 61 and the third light source 63 is substantially the same as the configuration of the second light source 62. Specifically, the first light source 61 is provided with a single first light emitting element 25 and a first flux width adjustment optical system 65. The first flux width adjustment optical system 65 is constituted by a cylindrical concave lens 651 and a cylindrical convex lens 652. The third light source 63 is provided with a single third light emitting element 27 and a third flux width adjustment optical system 67. The third flux width adjustment optical system 67 is constituted by a cylindrical concave lens 671 and a cylindrical convex lens 672. The colored light beams LB, LG, and LR emitted from the respective flux width adjustment optical systems 65, 66, and 67 are each a parallel light beam with the flux width in the Y-axis direction enlarged. In other words, each of the first flux width adjustment optical system 65, the second flux width adjustment optical system 66, and the third flux width adjustment optical system 67 is an afocal optical system including a cylindrical lens.
The rest of the configuration of the projector 50 is substantially the same as in the first embodiment.
In the present embodiment, there can be obtained substantially the same advantages as those of the first embodiment such as an advantage that it is possible to solve the problem of the deterioration of the brightness and the contrast in the light modulation device 21, the occurrence of the color unevenness, the light loss in the projection optical device 23, and the illuminance unevenness caused by using the light source having the coherency, an advantage that it is possible to decrease the number of the interfaces between the optical system and the air by reducing the optical components, and thus, it is possible to reduce the light loss caused by the interfacial reflection, an advantage that it is possible to increase the light use efficiency without using the optical system for forming the light into a rectangular shape, an advantage that the area illumination becomes possible, and an advantage that it is possible to perform the color display with a simple configuration without using a color filter, and thus, it is possible to prevent the degradation of the chromatic purity and the luminance of the display image.
In the case of the present embodiment, since the first light source 61, the second light source 62, and the third light source 63 are respectively provided with the flux width adjustment optical systems 65, 66, and 67, by appropriately setting the power in the Y-axis direction of each of the flux width adjustment optical systems 65, 66, and 67, it is possible to adjust the flux width in the Y-axis direction of each of the colored light beams LB, LG, and LR in accordance with the size of the light modulation device 21 irrespective of the number of the light emitting elements. Further, since the flux width adjustment optical systems 65, 66, and 67 are each an afocal optical system, it is possible to freely set the installation position in the X-axis direction of the light modulation device 21.
A fourth embodiment of the present disclosure will hereinafter be described using
A projector according to the present embodiment is substantially the same in basic configuration as that of the third embodiment, but is different in configuration of the flux width adjustment optical systems from that of the third embodiment.
In
As shown in
The light source device 80 according to the present embodiment is provided with a first light source 81, a second light source 82, a third light source 83, the transmissive optical part 14, the rotary drive device 15, the first reflecting element 17, and the second reflecting element 18.
The second light source 82 is provided with a single second light emitting element 26 and a second flux width adjustment optical system 86. The second flux width adjustment optical system 86 is formed of a single meniscus lens. The meniscus lens has a concave surface at the light incidence side, and a convex surface at the light exit side. The meniscus lens does not have power in the Z-axis direction, but has power in the Y-axis direction. Thus, the second flux width adjustment optical system 86 enlarges the flux width in the Y-axis direction of the green light beam LG0 emitted from the second light emitting element 26. Further, the green light beam LG emitted from the second flux width adjustment optical systems 86 is a parallel light beam with the flux width in the Y-axis direction enlarged.
The configuration of each of the first light source 81 and the third light source 83 is substantially the same as the configuration of the second light source 82. Specifically, the first light source 81 is provided with a single first light emitting element 25 and a first flux width adjustment optical system 85. The first flux width adjustment optical system 85 is formed of a single meniscus lens. The third light source 83 is provided with a single third light emitting element 27 and a third flux width adjustment optical system 87. The third flux width adjustment optical system 87 is formed of a single meniscus lens.
The rest of the configuration of the projector 70 is substantially the same as in the first embodiment.
In the present embodiment, there can be obtained substantially the same advantages as those of the first embodiment such as an advantage that it is possible to solve the problem of the deterioration of the brightness and the contrast in the light modulation device 21, the occurrence of the color unevenness, the light loss in the projection optical device 23, and the illuminance unevenness caused by using the light source having the coherency, an advantage that it is possible to decrease the number of the interfaces between the optical system and the air by reducing the optical components, and thus, it is possible to reduce the light loss caused by the interfacial reflection, an advantage that it is possible to increase the light use efficiency without using the optical system for forming the light into a rectangular shape, an advantage that the area illumination becomes possible, and an advantage that it is possible to perform the color display with a simple configuration without using a color filter, and thus, it is possible to prevent the degradation of the chromatic purity and the luminance of the display image.
Further, due to the flux width adjustment optical systems 85, 86, and 87, it is possible to obtain substantially the same advantages as those of the third embodiment such as an advantage that it is possible to adjust the flux width in the Y-axis direction of each of the colored light beams LB, LG, and LR in accordance with the size of the light modulation device 21 irrespective of the number of the light emitting elements, and an advantage that it is possible to freely set the installation position in the X-axis direction of the light modulation device 21.
Hereinafter, a fifth embodiment of the present disclosure will be described using
A projector according to the present embodiment is substantially the same in basic configuration as that of the first embodiment, but is different in configuration of the light source device from that of the third embodiment.
In
As shown in
The light source device 100 according to the present embodiment is provided with the first light source 11, the second light source 12, the third light source 13, the transmissive optical part 14, the rotary drive device 15, a light combining element 91, a third reflecting element 93, and a fourth reflecting element 94.
In the case of the present embodiment, each of the blue light beam LB emitted from the first light source 11, the green light beam LG emitted from the second light source 12, and the red light beam LR emitted from the third light source 13 directly enters the transmissive optical part 14 without an intervention of a reflecting element or the like. The first light source 11 is arranged at a position which rotates counterclockwise from the position of the second light source 12, and is tilted toward the +Z side with respect to the optical axis AX2. The third light source 13 is arranged at a position which rotates clockwise from the position of the second light source 12, and is tilted toward the −Z side with respect to the optical axis AX2.
Since the light sources 11, 12, and 13 are arranged as described above, the blue light beam LB, the green light beam LG, and the red light beam LR enter the transmissive optical part 14 at respective positions different from each other. Specifically, the blue light beam LB enters the transmissive optical part 14 at a first position P1. The green light beam LG enters the transmissive optical part 14 at a second position P2 different from the first position P1. The red light beam LG enters the transmissive optical part 14 at a third position P3 different from the first position P1 and the second position P2.
The light combining element 91 is disposed between the transmissive optical part 14 and the light modulation device 21 on the optical axis AX2. The light combining element 91 has a configuration in which a dichroic film for transmitting green light and red light and reflecting blue light, and a dichroic film for transmitting green light and blue light and reflecting red light cross each other to form an X shape. The light combining element 91 combines the blue light beam LB emitted from the transmissive optical part 14, the green light beam LG emitted from the transmissive optical part 14, and the red light beam LR emitted from the transmissive optical part 14 with each other. The blue light beam LB, the green light beam LG, and the red light beam LR combined with each other by the light combining element 91 each perpendicularly enter the light modulation device 21.
The third reflecting element 93 reflects the blue light beam LB, which is emitted from the transmissive optical part 14, toward the light combining element 91. The fourth reflecting element 94 reflects the red light beam LR, which is emitted from the transmissive optical part 14, toward the light combining element 91. It is desirable for the third reflecting element 93 and the fourth reflecting element 94 to be set in angle so that the blue light beam LB and the red light beam LR each perpendicularly enter the light combining element 91.
As described above, the blue light beam LB, the green light beam LG, and the red light beam LR enter the transmissive optical part 14 at respective positions P1, P2, and P3 different from each other, and are therefore emitted from the transmissive optical part 14 with respective phases different from each other. As a result, there is no chance for the blue light beam LB, the green light beam LG, and the red light beam LR to overlap each other in the same area when illuminating the light modulation device 21, and as shown in
As described above, the blue light beam LB forms a first illumination target area 21B shaped like a strip having a long axis in the Y-axis direction on the light modulation device 21. The green light beam LG forms a second illumination target area 21G shaped like a strip having a long axis in the Y-axis direction on the light modulation device 21. The red light beam LR forms a third illumination target area 21R shaped like a strip having a long axis in the Y-axis direction on the light modulation device 21. Each of the first illumination target area 21B, the second illumination target area 21G, and the third illumination target area 21R is scanned in the Z-axis direction on the light modulation device 21 with the rotation of the transmissive optical part 14.
A controller (not shown) vertically scans a blue partial image, a green partial image, and a red partial image obtained by dividing the whole image into strips in sync with the scanning of the first illumination target area 21B, the second illumination target area 21G, and the third illumination target area 21R. Thus, the light modulation device 21 performs the modulation of the colored light beams LB, LG, and LR different by the illumination target areas 21B, 21G, and 21R. Specifically, the light modulation device 21 performs the modulation of the blue light beam LB in the first illumination target area 21B, performs the modulation of the green light beam LG in the second illumination target area 21G, and performs the modulation of the red light beam LR in the third illumination target area 21R, and by scanning the illumination target areas 21B, 21G, and 21R in the Z-axis direction, a full-color image is formed.
The rest of the configuration of the projector 90 is substantially the same as in the first embodiment.
In the present embodiment, there can be obtained substantially the same advantages as those of the first embodiment such as an advantage that it is possible to solve the problem of the deterioration of the brightness and the contrast in the light modulation device 21, the occurrence of the color unevenness, the light loss in the projection optical device 23, and the illuminance unevenness caused by using the light source having the coherency, an advantage that it is possible to decrease the number of the interfaces between the optical system and the air by reducing the optical components, and thus, it is possible to reduce the light loss caused by the interfacial reflection, an advantage that it is possible to increase the light use efficiency without using the optical system for forming the light into a rectangular shape, an advantage that the area illumination becomes possible, and an advantage that it is possible to perform the color display with a simple configuration without using a color filter, and thus, it is possible to prevent the degradation of the chromatic purity and the luminance of the display image.
In the case of the present embodiment, unlike the embodiments previously described, since there is not adopted the projector of the system in which the three colored light beams are made to enter the single microlens from the respective directions different from each other to thereby spatially separate the three colored light beams from each other, it is possible to make all of the colored light beams LB, LG, and LR perpendicularly enter the light modulation device 21. In this case, according to the present embodiment, the state in which the blue light beam LB, the green light beam LG, and the red light beam LR each perpendicularly enter the light modulation device 21 is always maintained. Thus, it is possible to stably obtain an image excellent in display quality such as contrast or color reproducibility.
A sixth embodiment of the present disclosure will hereinafter be described using
A projector according to the present embodiment is substantially the same in basic configuration as that of the first embodiment, but is different in configuration of the light source device from that of the first embodiment.
In
As shown in
The light source device 120 according to the present embodiment is provided with a light source 122, the transmissive optical part 14, the rotary drive device 15, a light separation element 123, a fifth reflecting element 125, and a sixth reflecting element 126. The light source 122 is provided with the first light source 11, the second light source 12, the third light source 13, and a light combining optical system 127.
The first light source 11 is arranged in a posture in which the optical axis AX1 of the first light source 11 is perpendicular to the optical axis AX2 of the second light source 12. The third light source 13 is arranged in a posture in which the optical axis AX3 of the third light source 13 is perpendicular to the optical axis AX2 of the second light source 12. The first light source 11 emits the blue light beam LB toward the −Z side. The third light source 13 emits the red light beam LR toward the −Z side. The second light source 12 emits the green light beam LG toward the +X side. The first light source 11 is arranged at a side near to the second light source 12, and the third light source 13 is arranged at a side far from the second light source 12 in this example, but this arrangement can be reversed.
The light combining optical system 127 is provided with a first light combining element 113 and a second light combining element 114. The first light combining element 113 is disposed at a position where the optical axis AX1 and the optical axis AX2 cross each other. The first light combining element 113 is formed of a dichroic mirror which transmits green light, and reflects blue light. The second light combining element 114 is disposed at a position where the optical axis AX2 and the optical axis AX3 cross each other. The second light combining element 114 is formed of a dichroic mirror which transmits green light and blue light, and reflects red light. The light combining optical system 127 combines the blue light beam LB emitted from the first light source 11, the green light beam LG emitted from the second light source 12, and the red light beam LR emitted from the third light source 13 with each other to generate a white light beam LW. Thus, the light source 122 emits the white light beam LW. The white light beam LW enters the transmissive optical part 14 without being separated according to the wavelength band.
The light separation element 123 is disposed between the transmissive optical part 14 and the light modulation device 21 on the optical axis AX2. The light separation element 123 has a configuration in which a dichroic film for transmitting green light and red light and reflecting blue light, and a dichroic film for transmitting green light and blue light and reflecting red light cross each other to form an X shape. The light separation element 123 separates the white light beam LW having been emitted from the transmissive optical part 14 into the blue light beam LB, the green light beam LG, and the red light beam LR. The blue light beam LB is emitted from the transmissive optical part 14 toward the −Z side. The red light beam LR is emitted from the transmissive optical part 14 toward the +Z side. The green light beam LG is emitted from the transmissive optical part 14 toward the +X side, and then enters the light modulation device 21.
The fifth reflecting element 125 is disposed on the light path of the blue light beam LB emitted from the transmissive optical part 14 toward the −Z side. The fifth reflecting element 125 reflects the blue light beam LB emitted from the transmissive optical part 14 toward the −Z side to make the blue light beam LB thus reflected enter the light modulation device 21. The sixth reflecting element 126 is disposed on the light path of the red light beam LR emitted from the transmissive optical part 14 toward the +Z side. The sixth reflecting element 126 reflects the red light beam LR emitted from the transmissive optical part 14 toward the +Z side to make the red light beam LR thus reflected enter the light modulation device 21. The tilt angle θ5 of the fifth reflecting element 125 and the tilt angle θ6 of the sixth reflecting element 126 are both set larger than 45 degrees.
The blue light beam LB reflected by the fifth reflecting element 125 proceeds obliquely to the optical axis AX2 so as to approach the optical axis AX2. The red light beam LR reflected by the sixth reflecting element 126 proceeds obliquely to the optical axis AX2 so as to approach the optical axis AX2. Thus, the blue light beam LB reflected by the fifth reflecting element 125, the green light beam LG emitted from the transmissive optical part 14, and the red light beam LR reflected by the sixth reflecting element 126 enter the first microlens array 43 (see
The rest of the configuration of the projector 110 is substantially the same as in the first embodiment.
In the present embodiment, there can be obtained substantially the same advantages as those of the first embodiment such as an advantage that it is possible to solve the problem of the deterioration of the brightness and the contrast in the light modulation device 21, the occurrence of the color unevenness, the light loss in the projection optical device 23, and the illuminance unevenness caused by using the light source having the coherency, an advantage that it is possible to decrease the number of the interfaces between the optical system and the air by reducing the optical components, and thus, it is possible to reduce the light loss caused by the interfacial reflection, an advantage that it is possible to increase the light use efficiency without using the optical system for forming the light into a rectangular shape, an advantage that the area illumination becomes possible, and an advantage that it is possible to perform the color display with a simple configuration without using a color filter, and thus, it is possible to prevent the degradation of the chromatic purity and the luminance of the display image.
A seventh embodiment of the present disclosure will hereinafter be described using
A projector according to the present embodiment is substantially the same in basic configuration as that of the sixth embodiment, but is different in configuration of the light source from that of the sixth embodiment.
In
As shown in
The light source device 140 according to the present embodiment is provided with a light source 142, the transmissive optical part 14, the rotary drive device 15, the light separation element 123, the fifth reflecting element 125, and the sixth reflecting element 126. The light source 142 is provided with the first light source 11, the second light source 12, the third light source 13, and a light combining element 145.
The first light source 11 emits the blue light beam LB toward the −Z side. The second light source 12 emits the green light beam LG toward the +X side. The third light source 13 emits the red light beam LR toward the +Z side. The first light source 11 and the third light source 13 are arranged so as to be opposed to each other on the same axis.
The light combining element 145 is disposed at a position where the optical axis AX1 and the optical axis AX3 cross the optical axis AX2. The light combining element 145 has a configuration in which a dichroic film for transmitting green light and red light and reflecting blue light, and a dichroic film for transmitting green light and blue light and reflecting red light cross each other to form an X shape. The light combining element 145 combines the blue light beam LB emitted from the first light source 11, the green light beam LG emitted from the second light source 12, and the red light beam LR emitted from the third light source 13 with each other to emit the white light beam LW. The white light beam LW enters the transmissive optical part 14 without being separated according to the wavelength band.
The rest of the configuration of the projector 130 is substantially the same as in the sixth embodiment.
In the present embodiment, there can be obtained substantially the same advantages as those of the first embodiment such as an advantage that it is possible to solve the problem of the deterioration of the brightness and the contrast in the light modulation device 21, the occurrence of the color unevenness, the light loss in the projection optical device 23, and the illuminance unevenness caused by using the light source having the coherency, an advantage that it is possible to decrease the number of the interfaces between the optical system and the air by reducing the optical components, and thus, it is possible to reduce the light loss caused by the interfacial reflection, an advantage that it is possible to increase the light use efficiency without using the optical system for forming the light into a rectangular shape, an advantage that the area illumination becomes possible, and an advantage that it is possible to perform the color display with a simple configuration without using a color filter, and thus, it is possible to prevent the degradation of the chromatic purity and the luminance of the display image.
An eighth embodiment of the present disclosure will hereinafter be described using
A light source device according to the present embodiment is substantially the same in basic configuration as that of the sixth embodiment, but is different in configuration of the projector, and light to be emitted from the light source device from that in the sixth embodiment.
In
As shown in
The light source device 160 according to the present embodiment is provided with the light source 122, the transmissive optical part 14, and the rotary drive device 15. The light source 122 is provided with the first light source 11, the second light source 12, the third light source 13, and the light combining optical system 127.
The first light source 11 is arranged in a posture in which the optical axis AX1 of the first light source 11 is perpendicular to the optical axis AX2 of the second light source 12. The third light source 13 is arranged in a posture in which the optical axis AX3 of the third light source 13 is perpendicular to the optical axis AX2 of the second light source 12. The first light source 11 emits the blue light beam LB toward the −Z side. The third light source 13 emits the red light beam LR toward the −Z side. The second light source 12 emits the green light beam LG toward the +X side. The first light source 11 is arranged at a side near to the second light source 12, and the third light source 13 is arranged at a side far from the second light source 12 in this example, but this arrangement can be reversed.
The light combining optical system 127 is provided with the first light combining element 113 and the second light combining element 114. The first light combining element 113 is disposed at a position where the optical axis AX1 and the optical axis AX2 cross each other. The first light combining element 113 is formed of a dichroic mirror which transmits green light, and reflects blue light. The second light combining element 114 is disposed at a position where the optical axis AX2 and the optical axis AX3 cross each other. The second light combining element 114 is formed of a dichroic mirror which transmits green light and blue light, and reflects red light.
In the present embodiment, the blue light beam LB, the red light beam LR, and the green light beam LG are emitted from the transmissive optical part 14 toward the +X side, and then enter the light modulation device 21 in a time-sharing manner. As a result, there is no chance for the blue light beam LB, the green light beam LG, and the red light beam LR to overlap each other in the same area when illuminating the light modulation device 21, and scanning with the colored light beams is performed in the Z-axis direction in a time-sharing manner while illuminating strip-shaped areas extending in the Y-axis direction.
On the light modulation device 21 in the present embodiment, first, the blue light beam LB having the long axis in the Y-axis direction forms the first illumination target area, and at the same time, scanning with the blue light beam LB is performed on the light modulation device 21 with the rotation of the transmissive optical part 14. Then, the red light beam LR having the long axis in the Y-axis direction forms the second illumination target area, and at the same time, scanning with the red light beam LR is performed on the light modulation device 21 with the rotation of the transmissive optical part 14. Lastly, the green light beam LG having the long axis in the Y-axis direction forms the third illumination target area, and at the same time, scanning with the green light beam LG is performed on the light modulation device 21 with the rotation of the transmissive optical part 14. As described above, the illumination and the scanning with the colored light beams are performed on the light modulation device 21 in a time-sharing manner. It should be noted that it is assumed in the present embodiment that scanning with the illumination is performed on the light modulation device 21 in the order of the blue light beam LB, the red light beam LR, and the green light beam LG, but this is not a limitation.
The controller (not shown) in the present embodiment vertically scans the blue partial image, the green partial image, and the red partial image in sync with the scanning of the first illumination target area, the second illumination target area, and the third illumination target area described above. Thus, the light modulation device 21 performs the modulation of the colored light beams LB, LG, and LR different by the illumination target areas. Specifically, the light modulation device 21 performs the modulation of the blue light beam LB in the first illumination target area, performs the modulation of the green light beam LG in the second illumination target area, and performs the modulation of the red light beam LR in the third illumination target area, and by scanning the illumination target areas in the Z-axis direction, a full-color image is formed.
Further, periods of the first light emitting element 25, the second light emitting element 26, and the third light emitting element 27 to emit the light beams will be described. The first light emitting element 25 emits the light beam from when the incidence of the light beam is switched from the side surface 14c4 to the side surface 14c1 to when the incidence of the light beam is switched from the side surface 14c1 to the side surface 14c2 with the rotation of the transmissive optical part 14. Then, the second light emitting element 26 emits the light beam from when the incidence of the light beam is switched from the side surface 14c1 to the side surface 14c2 to when the incidence of the light beam is switched from the side surface 14c2 to the side surface 14c3 with the rotation of the transmissive optical part 14. Lastly, the third light emitting element 27 emits the light beam from when the incidence of the light beam is switched from the side surface 14c2 to the side surface 14c3 to when the incidence of the light beam is switched from the side surface 14c3 to the side surface 14c4 with the rotation of the transmissive optical part 14. By repeating the above, the first light emitting element 25, the second light emitting element 26, and the third light emitting element 27 emit the respective colored light beams in a time-sharing manner.
In the present embodiment, there can be obtained advantages such as an advantage that it is possible to solve the problem of the deterioration of the brightness and the contrast in the light modulation device 21, the occurrence of the color unevenness, the light loss in the projection optical device 23, and the illuminance unevenness caused by using the light source having the coherency, an advantage that it is possible to decrease the number of the interfaces between the optical system and the air by reducing the optical components, and thus, it is possible to reduce the light loss caused by the interfacial reflection, an advantage that it is possible to increase the light use efficiency without using the optical system for forming the light into a rectangular shape, an advantage that the area illumination becomes possible, and an advantage that it is possible to perform the color display with a simple configuration without using a color filter, and thus, it is possible to prevent the degradation of the chromatic purity and the luminance of the display image.
Further, in the case of the present embodiment, since there is not adopted the projector of the system in which the three colored light beams are made to enter the single microlens from the respective directions different from each other to thereby spatially separate the three colored light beams from each other, it is possible to make all of the colored light beams LB, LG, and LR perpendicularly enter the light modulation device 21. In this case, according to the present embodiment, the state in which the blue light beam LB, the green light beam LG, and the red light beam LR each perpendicularly enter the light modulation device 21 is always maintained. Thus, it is possible to stably obtain an image excellent in display quality such as contrast or color reproducibility. Further, by obtaining the configuration in which the colored light beams are emitted in a time-sharing manner, it is possible to decrease the amount of light entering the transmissive optical part 14 compared to when the three colored light beams enter the transmissive optical part 14 at a time, and therefore, it is possible to prevent the rise in temperature of the optical parts, and at the same time, there is made the contribution to the reduction of the influence of the thermal strain.
It should be noted that the scope of the present disclosure is not limited to the embodiments described above, and a variety of modifications can be provided thereto within the scope or the spirit of the present disclosure. Further, one aspect of the present disclosure can be provided with a configuration obtained by arbitrarily combining characterizing portions of the respective embodiments described above with each other.
In the light source device according to the embodiments described above, there is cited the example of the polygonal column having an even number of side surfaces as the shape of the transmissive optical part. From the viewpoint that the stray light rarely occurs, and the light use efficiency is high, the polygonal column having an even number of side surfaces is desirable. It should be noted that as long as a set of a plane of incidence and an exit surface parallel to each other are provided, it is possible to adopt a shape other than the polygonal column having an even number of side surfaces. Further, the “rotation” in the embodiments of the present application can include performing similar scanning by oscillating the transmissive optical part.
Besides the above, the specific descriptions of the shape, the number, the arrangement, the material, and so on of the constituents of the light source device and the projector are not limited to those in the embodiments described above, and can arbitrarily be modified. Further, although in the embodiments described above, there is described the example of installing the light source device according to the present disclosure in the projector using the liquid crystal panel, the example is not a limitation. The light source device according to the present disclosure can also be applied to a projector using a digital micromirror device as the light modulation device.
Hereinafter, the conclusion of the present disclosure will supplementarily be noted.
A light source device including a first light source configured to emit a first light beam in a first wavelength band, a second light source configured to emit a second light beam in a second wavelength band different from the first wavelength band, a third light source configured to emit a third light beam in a third wavelength band different from the first wavelength band and the second wavelength band, and a transmissive optical part which is formed of a light transmissive member rotatably supported, and which is configured to transmit the first light beam, the second light beam, and the third light beam, wherein the transmissive optical part is made rotatable centering on a rotational axis extending along a first direction crossing an incident direction of the first light beam, an incident direction of the second light beam, and an incident direction of the third light beam, a cross-sectional shape perpendicular to a principal ray of the first light beam emitted from the first light source is a shape having a long axis extending along the first direction, a cross-sectional shape perpendicular to a principal ray of the second light beam emitted from the second light source is a shape having a long axis extending along the first direction, a cross-sectional shape perpendicular to a principal ray of the third light beam emitted from the third light source is a shape having a long axis extending along the first direction, the first light beam enters the transmissive optical part at a first position, the second light beam enters the transmissive optical part at a second position different from the first position, the third light beam enters the transmissive optical part at a third position different from the first position and the second position, and in the transmissive optical part, a plane of incidence which the first light beam enters and an exit surface from which the first light beam entering the plane of incidence is emitted are parallel to each other, a plane of incidence which the second light beam enters and an exit surface from which the second light beam entering the plane of incidence is emitted are parallel to each other, and a plane of incidence which the third light beam enters and an exit surface from which the third light beam entering the plane of incidence is emitted are parallel to each other.
According to the configuration of Supplementary Note 1, the light beam emitted from each of the light sources is displaced in a direction perpendicular to the proceeding direction of the light beam while keeping the parallel state to the optical axis with the rotation of the transmissive optical part. Thus, it is possible to always make the light beam enter the illumination target surface at a constant angle.
The light source device described in Supplementary Note 1, wherein the transmissive optical part is configured to perform scanning with each of the first light beam, the second light beam, and the third light beam in a direction perpendicular to the first direction when rotating centering on the rotational axis to achieve a two-dimensional scan.
According to the configuration of Supplementary Note 2, it is possible to illuminate the illumination target area as the two-dimensional area only by using a single transmissive optical part.
The light source device described in one of Supplementary Note 1 and Supplementary Note 2, wherein the transmissive optical part has a first surface and a second surface crossing the rotational axis, and 2×m (m is a natural number no smaller than 2) side surfaces having contact with the first surface and the second surface, and the plane of incidence and the exit surface are two of the 2×m side surfaces, the two side surfaces being parallel to each other.
According to the configuration of Supplementary Note 3, since there is no light beam entering the side surfaces which are not parallel to each other, the stray light rarely occurs in the transmissive optical part, and thus, it is possible to increase the light use efficiency.
The light source device described in any one of Supplementary Note 1 through Supplementary Note 3, wherein the first light source includes a first light emitting element configured to emit light in the first wavelength band, the second light source includes a second light emitting element configured to emit light in the second wavelength band, the third light source includes a third light emitting element configured to emit light in the third wavelength band, and each of the first light emitting element, the second light emitting element, and the third light emitting element is a laser diode configured to emit a laser beam.
According to the configuration of Supplementary Note 4, since the laser beam as linearly-polarized light is emitted from each of the light sources, when using a liquid crystal panel as the light modulation device of the projector, it is possible to omit the incidence side polarization plate.
The light source device described in Supplementary Note 4, wherein the first light source includes a plurality of the first light emitting elements, the second light source includes a plurality of the second light emitting elements, the third light source includes a plurality of the third light emitting elements, the plurality of first light emitting elements is arranged along the first direction, the plurality of second light emitting elements is arranged along the first direction, and the plurality of third light emitting elements is arranged along the first direction.
According to the configuration of Supplementary Note 5, it is possible to generate the light having the cross-sectional shape having the long axis extending along the first direction without using an optical system such as a flux width adjustment optical system.
The light source device described in one of Supplementary Note 4 and Supplementary Note 5, wherein the first light source further includes a first flux width adjustment optical system configured to adjust a flux width in the first direction of the first light beam emitted from the first light emitting element, the second light source further includes a second flux width adjustment optical system configured to adjust a flux width in the first direction of the second light beam emitted from the second light emitting element, and the third light source further includes a third flux width adjustment optical system configured to adjust a flux width in the first direction of the third light beam emitted from the third light emitting element.
According to the configuration of Supplementary Note 6, it is possible to adjust the flux width in the first direction of each of the colored light beams in accordance with the size of the illumination target area irrespective of the number of the light emitting elements of each of the light sources.
The light source device described in Supplementary Note 6, wherein each of the first flux width adjustment optical system, the second flux width adjustment optical system, and the third flux width adjustment optical system is an afocal optical system including a cylindrical lens.
According to the configuration of Supplementary Note 7, it is possible to adjust the flux width in the first direction while keeping the parallelism of each of the colored light beams.
The light source device described in any one of Supplementary Note 1 through Supplementary Note 7, wherein the transmissive optical part is formed of quartz.
According to the configuration of Supplementary Note 8, since the Young's modulus and the thermal expansion coefficient of quartz are low, the thermal strain of the transmissive optical part is small, and it is possible to suppress the disturbance of the polarization direction of the light beam.
A projector including the light source device described in any one of Supplementary Note 1 through Supplementary Note 8, a light modulation device configured to modulate light including the first light beam, the second light beam, and the third light beam emitted from the transmissive optical part of the light source device based on image information, and a projection optical device configured to project the light modulated by the light modulation device.
According to the configuration of Supplementary Note 9, it is possible to realize the projector which is capable of performing the color display with a simple configuration, and which is excellent in image quality.
The projector described in Supplementary Note 9 further including a first reflecting element configured to reflect the third light beam emitted from the transmissive optical part, a second reflecting element configured to reflect the first light beam emitted from the transmissive optical part, and a light collecting element configured to collect each of the first light beam reflected by the second reflecting element, the second light beam emitted from the transmissive optical part, and the third light beam reflected by the first reflecting element to guide the first light beam, the second light beam, and the third light beam collected to the light modulation device, wherein the first light beam reflected by the second reflecting element, the second light beam emitted from the transmissive optical part, and the third light beam reflected by the first reflecting element enter the light collecting element from respective directions different from each other, the light modulation device includes a first sub-pixel configured to modulate the first light beam, a second sub-pixel configured to modulate the second light beam, and a third sub-pixel configured to modulate the third light beam, and the light collecting element is configured to make the first light beam emitted from the second reflecting element enter the first sub-pixel, the second light beam emitted from the transmissive optical part enter the second sub-pixel, and the third light beam emitted from the first reflecting element enter the third sub-pixel.
According to the configuration of Supplementary Note 10, it is possible to realize the projector which is capable of performing the color display with the light modulation device not provided with a color filter, and which is excellent in brightness and color reproducibility of the image.
The projector described in Supplementary Note 10, wherein the first reflecting element is disposed on a light path of the first light beam emitted from the first light source, and is configured to transmit the first light beam, and the second reflecting element is disposed on a light path of the third light beam emitted from the third light source, and is configured to transmit the third light beam.
According to the configuration of Supplementary Note 11, by changing the tilt angles of the respective reflecting elements to the optical axis, it is possible to adjust the incident angles of the first light beam and the third light beam with respect to the light collecting element.
The projector described in Supplementary Note 11, wherein an optical axis of the second light source is perpendicular to an optical axis of the first light source and an optical axis of the third light source.
According to the configuration of Supplementary Note 12, it is possible to increase the degree of freedom of the layout of the components constituting the projector, and at the same time, it is possible to achieve a reduction in size of the projector.
The projector described in Supplementary Note 9 further including a light combining element configured to combine the first light beam emitted from the transmissive optical part, the second light beam emitted from the transmissive optical part, and the third light beam emitted from the transmissive optical part with each other, wherein the first light beam is configured to form a first illumination target area having a long axis in the first direction on the light modulation device, the second light beam is configured to form a second illumination target area having a long axis in the first direction on the light modulation device, the third light beam is configured to form a third illumination target area having a long axis in the first direction on the light modulation device, each of the first illumination target area, the second illumination target area, and the third illumination target area is scanned in a second direction perpendicular to the first direction on the light modulation device with a rotation of the transmissive optical part, and the light modulation device is configured to perform a modulation of the first light beam in the first illumination target area, perform a modulation of the second light beam in the second illumination target area, and perform a modulation of the third light beam in the third illumination target area.
According to the configuration of Supplementary Note 13, it is possible to realize the projector capable of performing the color display without including the light collecting element such as a microlens array in the anterior stage of the light modulation device.
A light source device including a light source configured to emit light, and a transmissive optical part which is formed of a light transmissive member rotatably supported, and which is configured to transmit the light emitted from the light source, wherein the light source includes a first light emitting unit configured to emit a first colored light beam, a second light emitting unit configured to emit a second colored light beam different from the first colored light beam, and a third light emitting unit configured to emit a third colored light beam different from the first colored light beam and the second colored light beam, the transmissive optical part is made rotatable centering on a rotational axis extending along a first direction crossing an incident direction of the light, a cross-sectional shape perpendicular to a principal ray of the light emitted from the light source is a shape having a long axis extending along the first direction, the light emitted from the light source enters the transmissive optical part without being separated according to a wavelength band, and in the transmissive optical part, a plane of incidence which the light emitted from the light source enters, and an exit surface from which the light entering the plane of incidence is emitted are parallel to each other.
According to the configuration of Supplementary Note 14, the light emitted from the light source is displaced in a direction perpendicular to the proceeding direction of the light while keeping the parallel state to the optical axis with the rotation of the transmissive optical part. Thus, it is possible to always make the light enter the illumination target surface at a constant angle.
A light source device including a first light source configured to emit a first colored light beam, a second light source configured to emit a second colored light beam different from the first colored light beam, a third light source configured to emit a third colored light beam different from the first colored light beam and the second colored light beam, and a transmissive optical part which is formed of a light transmissive member rotatably supported, and which is configured to transmit the first colored light beam, the second colored light beam, and the third colored light beam respectively emitted from the first light source, the second light source, and the third light source, wherein the transmissive optical part is made rotatable centering on a rotational axis extending along a first direction crossing incident directions of the first colored light beam, the second colored light beam, and the third colored light beam, a cross-sectional shape perpendicular to principal rays of the first colored light beam, the second colored light beam, and the third colored light beam is a shape having a long axis extending along the first direction, the first light source, the second light source, and the third light source are configured to emit the first colored light beam, the second colored light beam, and the third colored light beam in respective periods different from each other, and in the transmissive optical part, a plane of incidence which the first colored light beam enters, and an exit surface from which the first colored light beam entering the plane of incidence is emitted are parallel to each other.
According to the configuration of Supplementary Note 15, it is possible to improve the problems of the degradation of the brightness and the contrast, occurrence of the color unevenness in the light modulation device, the light loss in the projection optical device, and the illuminance unevenness caused by using the light source having the coherency. Further, by obtaining the configuration in which the colored light beams are emitted in a time-sharing manner, it is possible to decrease the amount of light entering the transmissive optical part compared to when the three colored light beams enter the transmissive optical part at a time, and therefore, it is possible to prevent the rise in temperature of the optical parts, and at the same time, there is made the contribution to the reduction of the influence of the thermal strain.
A projector including the light source device described in one of Supplementary Note 14 and Supplementary Note 15, a light modulation device configured to modulate the light emitted from the transmissive optical part of the light source device based on image information, and a projection optical device configured to project the light modulated by the light modulation device.
According to the configuration of Supplementary Note 16, it is possible to realize the projector which is simple in configuration, and which is excellent in image quality.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-043616 | Mar 2023 | JP | national |
