Field of the Invention
The present invention relates to an illuminating device and a projection type video display.
Generally, an illuminating device used for a liquid crystal projector is formed of a lamp such as an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, and etc., and a parabolic reflector for collimating its irradiating light. In addition, in such the illuminating device, in order to reduce a non-uniformity of a light amount on an irradiating surface, there is sometimes provided an integrating function by a pair of fly's eye lenses (referred to as a function for superimposing and converging plural illuminating areas of predetermined shape formed by sampling within a plane surface by an optical device on an object to be illuminated). Furthermore, in recent years, from the viewpoint of power saving, or others, it is attempted to use a light-emitting diode (LED) as the light source (see Japanese Patent Application Laying-open No. 10-186507).
However, it appears to be a reality that a practical illuminating device using the light-emitting diode has not been realized.
In view of the above circumstances, it is an object of the present invention to provide a practical illuminating device using a solid light element such as a light-emitting diode and others, and a projection type video display using the illuminating device.
In order to solve the above-described problems, an illuminating device according to the present invention comprises a plurality of light sources formed of one or a plurality of solid light-emitting elements and arranged so as to face different directions one another, a lighting control means for allowing the solid light-emitting element to emit pulses of light, and an optical path changing means for generating a state where light emitted by a pulsed emission in one light source is guided to a specific optical path and a state where light emitted by a pulsed emission in another light source is guided to the specific optical path (hereinafter, referred to as a first configuration in this section).
A peak light amount is further increased in a case where the solid light-emitting elements are allowed to emit pulses of light by passing a large amount of electric currents instantaneously than in a case where the solid light-emitting elements are allowed to emit light in a steady-state manner by passing a steady-state current, so that an amount of emitted light in the illuminating device is increased. In addition, between a pulsed emission of a certain solid light-emitting element and a next pulsed emission of the same solid light-emitting element, it is possible to allow another solid light-emitting element to emit pulses of light. As a result, it is possible to further increase the total light amount in this case than in a case where solid light-emitting element is allowed to emit light in a steady-state manner. Herein, in a case where a plurality of light sources face the same direction (optical axes of the respective light sources are in parallel with one another), the substantial light-emitting area becomes larger than an object to be illuminated, so that a parallelism of light fluxes guided to the object to be illuminated is likely to be reduced. On the contrary, with such the invention, a plurality of light sources are faced in different directions and the optical path changing means is provided. As a result, a substantial light-emitting area becomes smaller than the object to be illuminated, so that the parallelism of light fluxes guided to the object to be illuminated can be improved. In other words, it is possible shorten a distance from the illuminating device to the object to be illuminated.
In the above-described first configuration, the optical path changing means may be formed of a transmission and reflection switching means for switching between the transmission and the reflection. The transmission and reflection switching means may be formed of a switching diffraction element for switching between the transmission and the reflection by an energization control synchronous with the pulsed emission. In addition, in the illuminating device according to such the configuration, three light sources are provided, and the switching diffraction elements may be arranged crosswise on a crossing position of the light emitted from the three light sources.
Furthermore, in an illuminating device provided with the transmission and reflection switching means, the transmission and reflection switching means may have transmitting regions and reflecting regions alternately in a plane surface and may switch positions of the transmitting regions and the reflecting regions by a reciprocating movement synchronous with the pulsed emission.
Or, in an illuminating device provided with the transmission and reflection switching means, the transmission and reflection switching means may have the transmitting regions and the reflecting regions alternately in a circular disk, and may switch positions of the transmitting regions and the reflecting regions by a rotation synchronous with the pulsed emission.
In the first configuration, the optical path changing means may be formed of a transmission optical path changing means for changing an optical path direction when light is transmitted. In an illuminating device of such the configuration, the transmission optical path changing means may be formed of a switching diffraction element for changing an advancing direction of light by diffraction according to an energization control synchronous with the pulsed emission. Furthermore, in an illuminating device according to such the configuration, three light sources are provided, and the switching diffraction elements may be arranged crosswise on a crossing position of light emitted from the three light sources.
In the first configuration, the optical path changing means may be formed of a reflection optical path changing means for changing an advancing direction of light by reflection. In an illuminating device of such the configuration, the reflection optical path changing means may be formed of a mirror device for changing a direction of a mirror by an energization control synchronous with the pulsed emission.
The illuminating devices of such the configurations may comprise a first fly's eye lens provided on a light-emission side of each light source, and a second fly's eye lens provided on the specific optical path, paired with the first fly's eye lens, and integrating and guiding light to an object to be illuminated. In addition, in this configuration, the illuminating device may comprise a polarization conversion system on a light-exit side of the second fly's eye lens.
Or, in this configuration, the illuminating device may comprise a tube-shaped or stick-shaped optical integrator on the specific optical path.
In the illuminating devices of such the configurations, each light source may emit light in the same one color (hereinafter, referred to as a second configuration in this section). Or, each light source may emit light in white or light of respective colors to be the light in white (hereinafter, referred to as a third configuration in this section).
Moreover, a projection type video display according to the present invention comprises a plurality of illuminating devices each of which emits light in different color. At least one of the illuminating devices is the illuminating device according to the second configuration, light of respective colors emitted from the respective illuminating devices is optically modulated by each display panel, and the modulated light of respective colors is combined and projected.
Furthermore, a projection type video display according to the present invention comprises a plurality of illuminating devices each of which emits light in different color. At least one of the illuminating devices is the illuminating device according to the second configuration, light of respective colors emitted from the respective illuminating devices is guided in the same direction and optically modulated by a single display panel, and the modulated light is projected.
Furthermore, a projection type video display according to the present invention comprises the illuminating device according to the third configuration. Light in white emitted from the illuminating device is optically modulated by a single display panel and the modulated light is projected.
Furthermore, a projection type video display according to the present invention comprises the illuminating device according to the third configuration. Light in white emitted from the illuminating device is separated into light in red, light in green, light in blue, light of respective colors is optically modulated by each display panel, and the modulated light of respective colors is combined and projected.
Moreover, in the first configuration, the illuminating device comprises a first polarization conversion system for converting light emitted from a first light source out of the plurality of light sources into polarized light of a first polarizing direction, and a second polarization conversion system for converting light emitted from a second light source different from the first light source into polarized light of a second polarizing direction perpendicular to the first polarizing direction. The optical path changing means guides the light emitted from the first light source and converted into the polarized light of the first polarizing direction to a specific optical path by one of the two functions, transmission and reflection, and guides the light emitted from the second light source and converted into the polarized light of the second polarizing direction to the specific optical path by the other of the two function, the transmission and the reflection (hereinafter, referred to as a fourth configuration in this section).
Such the fourth configuration is a configuration utilizing the transmission and the reflection based on a difference of the polarized light, and a light amount is increased further in a case where the solid light-emitting elements are allowed to emit pulses of light by passing a large amount of electric currents instantaneously than in a case where the solid light-emitting elements are allowed to emit light in a steady-state manner by passing a steady-state current, so that an amount of emitted light in the illuminating device of the fourth configuration is increased.
In the fourth configuration, amounts of the light emitted from the first light source and the light emitted from the second light source may be rendered different each other such that amounts of the polarized light of the first polarizing direction and the polarized light of the second polarizing direction obtained by passing through the optical path changing means are equalized.
In the fourth configuration and configurations depending thereon, an illuminating device may comprise a first fly's eye lens provided on a light-emission side of each light source, and a second fly's eye lens provided on the specific optical path, paired with the first fly's eye lens, and integrating and guiding light to an object to be illuminated. Or, an illuminating device may comprise a tube-shaped or stick-shaped optical integrator on the specific optical path.
In the fourth configuration and configurations depending thereon, an illuminating device may comprise a switching polarized light rotating element for switching between a function state where a polarizing direction of received light is rotated by 90 degrees and a function state where the polarizing direction is not rotated, by on and off of an energization, and a switching circuit for controlling the switching polarized light rotating element. The switching polarized light rotating element is arranged on the specific optical path, the lighting control means performs a lighting control so as to stagger timing of the pulsed emissions of the first light source and the second light source, the switching circuit turns on and off the switching polarized light rotating element in synchronization with timing of the pulsed emission of the solid light-emitting element, and polarizing directions of light obtained by passing through the switching polarized light rotating element are redirected in a common direction (hereinafter, referred to as a fifth configuration in this section).
In the fourth configuration and configurations depending thereon (except for the above-described fifth configuration), each light source may emit light in the same one color (hereinafter, referred to as a sixth configuration in this section). In the fourth configuration and configurations depending thereon (except for the fifth configuration), each light source may emit light in white or light of respective colors to be the light in white (hereinafter, referred to as a seventh configuration in this section).
Furthermore, a projection type video display according to the present invention comprises a plurality of illuminating devices each of which emits light in different color. At least one of the illuminating devices is the illuminating device according to the sixth configuration, light of respective colors emitted from the respective illuminating devices is optically modulated by each display panel, and the modulated light of respective colors is combined and projected.
In addition, a projection type video display according to the present invention comprises a plurality of illuminating devices each of which emits light in different color. At least one of the illuminating devices is the illuminating device according to the sixth configuration, the light of respective colors emitted from the respective illuminating devices is guided in one direction and optically modulated by a single display panel, and the modulated light is projected.
Furthermore, a projection type video display according to the present invention comprises the illuminating device according to the seventh configuration. The light in white or the light of respective colors to be the light in white, emitted from the illuminating device, is optically modulated by a single display panel, and the modulated light is projected.
Furthermore, a projection type video display according to the present invention comprises the illuminating device according to the seventh configuration. Light in white emitted from the illuminating device is separated into light of respectively different colors, the light of respective colors is optically modulated by each display panel, and the modulated light of respective colors is combined and projected.
A projection type video display provided with an illuminating device according to the sixth configuration or the seventh configuration comprises a liquid crystal display panel without a light-incidence side polarizer as the display panel, and a panel driving circuit for driving the liquid crystal display panel. The lighting control means performs a lighting control so as to stagger timing of the pulsed emissions of the first light source and the second light source, and the panel driving circuit, at the time that the polarized light of the first polarizing direction is incident on the liquid crystal display panel, supplies to the liquid crystal display panel one of two video signals, that is, a video signal generated for a liquid crystal panel in which a polarizing direction of incident light crosses a transmitting direction of a light-exit side polarizer and a video signal generated for a liquid crystal panel in which the polarizing direction of incident light is in parallel with the transmitting direction of the light-exit side polarizer, on the other hand, at the time that the polarized light of the second polarizing direction is incident on the liquid crystal display panel, supplies to the liquid crystal display panel the other of the above-mentioned two video signals.
In the fifth configuration, each light source may emit light in the same one color (hereinafter, referred to as an eighth configuration in this section). In the fifth configuration, each light source may emit light in white or light of respective colors to be the light in white (hereinafter, referred to as a ninth configuration in this section).
Furthermore, a projection type video display according to the present invention comprises a plurality of illuminating devices each of which emits light in different color. At least one of the illuminating devices is the illuminating device according to the eighth configuration, light of respective colors from the respective illuminating devices is optically modulated by each display panel, and the modulated light of respective colors is combined and projected.
Furthermore, a projection type video display according to the present invention comprises a plurality of illuminating devices each of which emits light in different color. At least one of the illuminating devices is the illuminating device according to the eighth configuration, light of respective colors emitted from the respective illuminating devices is guided in one direction and optically modulated by a single display panel, and the modulated light is projected.
Furthermore, a projection type video display according to the present invention comprises the illuminating device according to the ninth configuration. The light in white or light of respective colors to be the light in white, emitted from the illuminating device, is optically modulated by a single display panel, and the modulated light is projected.
Furthermore, a projection type video display according to the present invention comprises the illuminating device according to the ninth configuration. Light in white is separated into light of respectively different colors, the light of respective colors is optically modulated by each display panel, and the modulated light of respective colors is combined and projected.
These projection type video displays provided with the illuminating device according to the eighth configuration or the ninth configuration may comprise a liquid crystal display panel as the display panel.
In a projection type video display provided with the illuminating device according to the fourth configuration, the fifth configuration, the sixth configuration, the seventh configuration, the eighth configuration, or the ninth configuration, a level of a video signal supplied to the display panel in receiving polarized light of a first polarizing direction and a level of a video signal supplied to the display panel in receiving polarized light of a second polarizing direction may be rendered different each other. In addition, in these illuminating devices or projection type video displays, it is preferable that the optical path changing means is a polarizing beam splitter made of glass in a cubic shape.
As described above, according to the present invention, the illuminating device has a plurality of light sources formed of one or a plurality of solid light-emitting elements, and the solid light-emitting element is allowed to emit pulses of light. Accordingly, it is possible to totally increase light amount compared to a case in which a solid light-emitting element is allowed to emit light in a steady-state manner. As a result, it is possible to render a substantial light-emitting area smaller than the object to be illuminated, so that the parallelism of the light fluxes guided to the object to be illuminated can be improved.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Hereinafter, a projection type video display of a first embodiment of the present invention will be described on the basis of FIGS. 1 to 11. It is noted that, in every example of the embodiment 1, light from a plurality of light sources is guided to the same optical path. However, a configuration in which a difference in wavelength of light is utilized (for example, a configuration in which a dichroic mirror, etc. are used) and a configuration in which a difference in polarization (for example, a configuration in which light is combined by utilizing transmission of P-polarized light and reflection of S-polarized light) are not adopted. That is, a configuration in which light sources that emit light of the same quality in view of color and polarization are used as respective light sources is realized.
The illuminating device 1 is provided with a first light source 12A in which LED chips 11 . . . are arranged in an array shape and lens cells 14 . . . are arranged on a light-emission side of each of the LED chips 11, and a second light source 12B in which LED chips 11 . . . are arranged in an array shape and lens cells 14 . . . are arranged on a light-emission side of each of the LED chips 11 (hereinafter, a numeral “12” is used when generally referring to the light source). The two light sources 12 of each illuminating device 1 are arranged such that main light-emission optical axes thereof are perpendicular to each other. Moreover, a time-division switching mirror 21 is provided at a crossing position of the main light-emission optical axes. The time-division switching mirror 21 is arranged obliquely by 45 degrees to each of the main light-emission optical axes of the two light sources.
Furthermore, each illuminating device 1 is provided with an integrator lens 13 for integrating and guiding light emitted from each LED chip 11 and collimated by the lens cell 14 to the liquid crystal display panel 3. A first fly's eye lens 13a of the integrator lens 13 is arranged at a light-emission side of each light source 12. In addition, a second fly's eye lens 13b of the integrator lens 13 is arranged at a rear side (light-exit side) of the time-division switching mirror 21. Each pair of lenses of the fly's eye lenses 13a, 13b guides the light emitted from each LED chip 11 to an entire surface of the liquid crystal display panel 3. The LED chips 11 . . . are molded by a transparent resin, and as a result the transparent resin being formed in a convex shape, the lens cells 14 . . . are formed. The LED chips 11 and the lens cells 14 may be in a round shape. However, in this embodiment, the LED chips 11 and the lens cells 14 are formed in a square shape, and moreover, aspect ratios thereof coincide with that of the liquid crystal display panel 3.
A polarization conversion system 22 is provided on the light-exit side of the fly's eye lens 13b. The polarization conversion system 22 is structured of a polarization beam splitter array (hereinafter, referred to as a PBS array). The PBS array is provided with a polarized light separating surface and a retardation plate (½ λ plate). Each polarized light separating surface of the PBS array transmits P-polarized light, for example, out of light from the integrator lens 13, and changes an optical path of S-polarized light by 90 degrees. The S-polarized light having the optical path changed is reflected by an adjacent polarized light separating surface, converted into the P-polarized light by the retardation plate provided on a front side (light-exit side) of the polarized light separating surface, and given off therefrom. On the other hand, the P-polarized light that passes through the polarized light separating surface is given off as it is. That is, in this case, approximately all the light is converted into the P-polarized light. In the above-described example, a configuration in which all the light is converted into the P-polarized light is described. However, a configuration in which all the light is converted into the S-polarized light by providing the retardation plate at a position where the P-polarized light is given off may be adopted.
As the time-division switching mirror 21 may be structured by using the DigiLens (a registered trademark) which is a switching diffraction element, for example, (Published Japanese translations of PCT international publication for patent applications No. 2002-520648 (see paragraph [0008] and [0009], in particular), and Published Japanese translations of PCT international publication for patent applications No. 2002-525646). It is noted that, if the switching diffraction element is suitable for the P-polarized light, for example, as shown in
A light source lighting control part, not shown, allows the first light source 12A and the second light source 12B to alternately emit pulses of light in each illuminating device 1.
As described above, the LED chips 11 are allowed to sequentially emit pulses of light, so that it is possible to totally increase the light amount compared to a case in which a plurality of solid light-emitting elements are allowed to emit light in a steady-state manner. In addition, a plurality of light sources 12 are respectively directed in different directions, and the time-division switching mirror 21 (optical path changing means) is provided. As a result, a substantial light-emitting area is smaller than the object to be illuminated, so that it is possible to improve a parallelism of light fluxes guided to the object to be illuminated. In other words, it is possible to downsize the projection type video display by shortening a distance between the condenser lenses 23, 24. Moreover, it is possible to utilize a light source that emits light of equal quality in view of color and polarization as each light source.
It is noted that each light source 12 is composed of a plurality of LEDs in the example above, however it is not always the case, and it is possible that the light source 12 is composed of one LED. Much the same is true on the light source 12 used in the illuminating device 1 exemplified below.
It is noted that the projection type video display may be provided with an illuminating device 1R, an illuminating device 1G, and an illuminating device 1B, light of respective colors from each illuminating device 1 may be guided in a single direction using a dichroic mirror, etc., and optically modulated by a single display panel. In this case, the illuminating device 1R, the illuminating device 1B, and the illuminating device 1B are lighted sequentially and a red color-use image, a green color-use image, and a blue color-use image may be displayed sequentially on the single display panel.
It is noted that the reciprocating driving mirror 41 is driven in the directions indicated by arrows in
Furthermore, in a configuration in which the time-division switching mirror (see
In the configuration shown in
A micro mirror device 45 is provided at a crossing position of optical axes of the two light sources 12. The micro mirror device 45 is arranged at an angle of 45 degrees with the optical axis of the light source 12B and at an angle of 90 degrees with the optical axis of the light source 12A. The micro mirror device 45 is formed of a number of micro mirrors. At a time of OFF-energization, as shown in
A rod integrator 51 (may be a hollow member of which inner surface is a mirror surface) formed of a glass pole is provided on the specific optical path. As a result of light passing through the rod integrator 51 with being reflected, a parallelism of the light flux is improved, and it is possible to obtain a surface light source having a uniform brightness.
It is noted that the light source 12A and the light source 12B are arranged such that light-emitting optical axes intersect at an angle of 45 degrees in the configuration in
The illuminating device 1W in the above-described
It is noted that the digital micro mirror device (DMD) drives each micro mirror individually in order to display an image. However, the micro mirror device 45 may be configured to drive all the micro mirrors all together. In addition, the micro mirror device 45 may be configured to drive each micro mirror by a piezoelectric element and others.
An integrator lens formed of a pair of fly's eye lenses may be provided on a light-exit side of the rod integrator 51 shown in
An illuminating device 1B shown in
An illuminating device 1B shown in
Hereinafter, an illuminating device and a projection type video display according to a second embodiment of the present invention will be described on the basis of FIGS. 12 to 22.
The light source 102 is a light source that emits light in white or light of respective colors to be the light in white, and as shown in
The polarization conversion system 103, as shown also in
Herein, a first polarization conversion system 103 is so arranged that light that is to be the P-polarized light for the polarized light mixing surface (polarized light separating surface) of the polarized light mixing element 101 is supplied from the first light source 102A. Similarly, a second polarization conversion system 103B is so arranged that light that is to be the S-polarized light for the polarized light mixing surface (polarized light separating surface) is supplied from the first light source 102B.
A LED lighting control circuit, not shown, allows the first light source 102A and the second light source 102B in the illuminating device 100A to alternately emit pulses of light.
A frequency of the pulsed emission of each light source 102 is 120 Hz. Accordingly, a period of the pulsed emission (lighting period) of each light source 102 is approximately 8.3 milliseconds (msec). It is noted that, as shown also in
Incidentally, a light amount of the P-polarized light that passes through the polarized light mixing surface (polarized light separating surface) in the polarized light mixing element 101 decreases, compared to a light amount of the S-polarized light that is reflected by the polarized light mixing surface (polarized light separating surface). It is not desirable that such the light amount difference is caused. Therefore, it is preferable to equalize light amounts of the P-polarized light and the S-polarized light guided to the rod integrator 104 by controlling power supplied to the second light source 102B, for example. Or, two light sources 102A, 102B which the same amount of power is supplied to and yet emit a different amount of light may be adopted. Or, such a correction described below may be performed. That is, a luminance signal of a video signal to be supplied when the first light source 102A is lighted is rendered higher than a luminance signal of a video signal to be supplied when the second light source 102B is lighted. In other words, the light amount difference between the P-polarized light and the S-polarized light may be eliminated by processing the video signals. Such the processes can be applied to a configuration example below.
A liquid crystal display panel 3F is a transmission type liquid crystal display panel provided with a color filter. A light-incidence-side polarizer of the liquid crystal display panel 3F transmits the S-polarized light. The liquid crystal display panel 3F is driven by an LDC driver 122. In addition, the first light source 102A and the second light source 102B are pulse-driven with phases thereof being shifted by 180 degrees each other by an LED lighting circuit 123. Then, the LCD driver 122, the LED lighting circuit 123, and the π-cell switch circuit 121 are controlled by a control circuit 124. An ON/OFF edge (switching edge) of the π-cell 105, as shown in
Structure of the liquid crystal display panel 3F′ is equivalent to structure in which the light-incidence-side polarizer is removed from the liquid crystal display panel 3X. In addition, the LCD driver 122 switches between a supply of a video signal for a case that the liquid crystal display panel 3F′ is regarded as the normally-white-type and a supply of a video signal for a case that the liquid crystal display panel 3F′ is regarded as a normally-black-type, according to timing of switching between the pulsed emission of the first light source 102A and the second light source 102B (switching between the P-polarized light and the S-polarized light). That is, the LCD driver 122, at the time that the polarized light of a first polarizing direction is incident on the liquid crystal display panel 3F′, supplies to the liquid crystal display panel 3F′ one of two signals, that is, a video signal generated for a liquid crystal panel in which a polarizing direction of incident light crosses a transmitting direction of a light-exit side polarizer, and a video signal generated for a liquid crystal panel in which the polarizing direction of incident light is in parallel with the transmitting direction of the light-exit side polarizer. On the other hand, the LCD driver 122, at the time that the polarized light of a second polarizing direction is incident on the liquid crystal display panel 3F′, supplies to the liquid crystal display panel 3F′ the other of the above-mentioned two video signals.
Hereinafter, a specific description will be further given. It is noted that, in the description below, the light-exit-side polarizer of the liquid crystal display panel 3F′ transmits the S-polarized light. At a timing that the first light source 102A is lighted and the P-polarized light is emitted, the LCD driver 122 supplies a normally white-use video signal to the liquid crystal display panel 3F′. When the video signal equivalent to a white color is supplied to the liquid crystal display panel 3F′ (that is, when the energization to the pixels of the liquid crystal display panel 3F′ is turned off), the P-polarized light incident on the liquid crystal display panel 3F′ becomes the S-polarized light as a result the polarizing direction being rotated by 90 degrees and can pass through the light-exit-side polarizer. As a result, the display becomes a white display. On the other hand, at a timing that the second light source 102B is lighted and the S-polarized light is emitted, the LCD driver 122 supplies a normally black-use video signal to the liquid crystal display panel 3F′. When the video signal equivalent to the white color is supplied to the liquid crystal display panel 3F′ (that is, when the energization to the pixels of the liquid crystal display panel 3F′ is turned on), the polarizing direction of the S-polarized light incident on the liquid crystal display panel 3F′ is not rotated, so that the S-polarized light can pass through the light-exit-side polarizer and the display becomes the white display.
Therefore, with the projection type video display shown in
It is noted that, in the three-panel type configuration in
Furthermore, a configuration in which the light in white emitted from the illuminating device 100A or the illuminating device 100B is separated into light of respective colors by a dichroic mirror and others, and the light of respective colors is respectively guided to the respective colors-use liquid crystal display panels may also be adopted. Modulated light (the light of respective colors) modulated by passing through the liquid crystal display panels is combined by the cross dichroic prism 4, and changed to full-color image light. This full-color image light is projected by a projection lens, and displayed on a screen.
In addition, in a case of using the illuminating device 100A in which the S-polarized light is emitted as it is and P-polarized light is emitted as it is, the first light source 102A and the second light source 102B need not necessarily be lighted alternately. For example, two kinds of combinations of LED chips for emitting the light in white in each light source may be prepared. The instant the LED chips of one combination are allowed to emit pulses of light in the first light source, the LED chips of the same combination are similarly allowed to emit pulses of light in the second light source. Moreover, the instant the LED chips of the other combination are similarly allowed to emit pulses of light in the first light source, the LED chips of the same combination are allowed to emit pulses of light in the second light source. In this case, the light amount difference between the P-polarized light and the S-polarized light still exists. However, the P-polarized light and S-polarized light emitted at the same time are combined, so that it is possible to prevent an amount of light emitted from the illuminating device 100A from changing. Such the configuration (control) can also be applied to an illuminating device that emits light of respective colors.
Furthermore, a time-division full-color projection type video display using one piece of DMD and the illuminating device 100A can be configured. For example, when the light in red-use LED chips of the first light source 102A and the second light source 102B are made to emit pulses of light, a red color-use video signal is supplied to the DMD, when the light in green-use LED chips of the first light source 102A and the second light source 102B are made to emit pulses of light, a green color-use video signal is supplied to the DMD, and when the light in blue-use LED chips of the first light source 102A and the second light source 102B are made to emit pulses of light, a blue color-use video signal is supplied to the DMD. That is, it is possible that the video display panels are driven by a time-dividing manner by synchronizing with respective timings of the pulsed emission of the respective colors-use LED chips.
Moreover, a time-division full-color projection type video display using one liquid crystal display panel and the illuminating device 100B can be configured. For example, in a state where the red color-use video signal is supplied to the one liquid crystal display panel, the light in red-use LED chips of the first light source 102A are made to emit pulses of light (at this time, the π-cell 105 is off, for example), and in addition, the light in red-use LED chips of the second light source 102B are made to emit pulses of light (at this time, the π-cell 105 is on, for example). Next, in a state where the green color-use video signal is supplied to the one liquid crystal display panel, the light in green-use LED chips of the first light source 102A are made to emit pulses of light (at this time, the π-cell 105 is off, for example), and in addition, the light in green-use LED chips of the second light source 102B are made to emit pulses of light (at this time, the π-cell 105 is on, for example). Next, in a state where the blue color-use video signal is supplied to the one liquid crystal display panel, the light in blue-use LED chips of the first light source 102A are made to emit pulses of light (at this time, the π-cell 105 is off, for example), and in addition, the light in blue-use LED chips of the second light source 102B are made to emit pulses of light (at this time, the n-cell 105 is on, for example). That is, each of the respective colors-use video signals is supplied to the liquid crystal display panel, the LED chips corresponding to the color indicated by the video signal are lighted sequentially in the two light sources, and then, the switching of the π-cell 105 is performed according to the timing of the lighting. In this case, the polarized light mixing element (the π-cell) capable of switching at a high frequency is desirable.
Furthermore, in the light source 102 used for the illuminating devices described above, as shown in
Moreover, each illuminating device may be provided with an integrator lens formed of a first fly's eye lens and a second fly's eye lens instead of the rod integrator 104. The first fly's eye lens is arranged on the light-exit side of each polarization conversion system 103. In addition, the second fly's eye lens is arranged on the light-exit side of the polarization mixing element 101. It is noted that the second fly's eye lens are shared by a plurality of light sources. Each pair of lenses of the first fly's eye lens and the second fly's eye lens guides light emitted from each light source to an entire surface of the video display element.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
2004-220077 | Jul 2004 | JP | national |
2005-184237 | Jun 2005 | JP | national |