The present application is based on, and claims priority from JP Application Serial Number 2023-006815, filed Jan. 19, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a virtual image display device and a head-mounted display apparatus that enable observation of a virtual image, and more particularly to a virtual image display device and the like of a see-through type that enable visual recognition of an external image.
As a see-through type virtual image display device that enables visual recognition of an outside world, a virtual image display device is known that includes a liquid crystal panel including an image display region and a transparent display region formed surrounding the image display region, and a light-guiding plate that guides backlight incident from a light source on an end portion, and in which the light-guiding plate includes a light-emitting region that irradiates the image display region of the liquid crystal panel with the backlight, and a light-transmitting region that transmits ambient light (WO 2016/056298). The display device is configured such that ambient light reaches an observer from the light-transmitting region of the light-guiding plate and the transparent display region of the liquid crystal panel, and the ambient light is transmitted through the light-emitting region of the light-guiding plate and the image display region of the liquid crystal panel and reaches the observer during a period in which the image display region is not irradiated with the backlight. With such a configuration, see-through display in which image light and ambient light are superimposed on each other is achieved.
In the above-described device, processing such as formation of dots and application of a scattering material is performed on the light-emitting region of the light-guiding plate, and the ambient light passing through the image display region of the liquid crystal panel passes through the processed light-emitting region, so that see-through transmittance decreases in a vicinity of a center of a visual field corresponding to the image display region. In order to achieve see-through display with high see-through transmittance in the vicinity of the center of the visual field, an optical system or the like with high see-through transmittance is separately required, which leads to an increase in size.
A virtual image display device according to an aspect of the present disclosure includes: a display member including a wavelength-converting region as a pixel display region, the wavelength-converting region being configured to emit fluorescence upon being excited by image light, a projection optical system configured to irradiate the wavelength-converting region with the image light as excitation light having a single wavelength, a light-blocking member arranged at an external side of the display member and configured to suppress incidence of external light on the wavelength-converting region, a first polarizing member arranged at a face side of the display member and including a first polarizing region provided corresponding to the wavelength-converting region, the first polarizing region being configured to restrict the image light displayed by the display member to a first polarization direction, a second polarizing member arranged at an external side of a position of the first polarizing member and including a second polarizing region configured to restrict the external light to a second polarization direction different from the first polarization direction, and a polarization separation lens element arranged at a face side of the first polarizing member and having refractive power configured to selectively act on polarized light of the image light.
With reference to
The HMD 200 includes a first virtual image display device 100A for a right eye, a second virtual image display device 100B for a left eye, a pair of temples 100C that support the virtual image display devices 100A and 100B, and a user terminal 90 being an information terminal. The first virtual image display device 100A is a first device 1A, and is constituted by a first display driving unit 102a that is arranged at an upper part, a first display optical system 103a that covers a front of the eye, and a light-transmitting cover 104a that covers the first display optical system 103a from the external side or a front side thereof. The second virtual image display device 100B is a second device 1B, and is constituted by a second display driving unit 102b that is arranged at an upper part, a second display optical system 103b that covers the front of the eye, and a light-transmitting cover 104b that covers the second display optical system 103b from the external side or the front side thereof. The HMD 200 obtained by combining the first virtual image display device 100A being the first device 1A and the second virtual image display device 100B being the second device 1B with each other is also a virtual image display device in a broader sense. The pair of temples 100C are mounting members or support devices 106 to be mounted on a head of the wearer US. The temples 100C support an upper end side of the pair of display optical systems 103a and 103b and an upper end side of the pair of light-transmitting covers 104a and 104b via the display driving units 102a and 102b integrated in appearance. A combination of the pair of display driving units 102a and 102b is referred to as a driving device 102. A combination of the pair of light-transmitting covers 104a and 104b is referred to as a shade 104.
As illustrated in
The composite display member 20 includes a plurality of repetition units 20a arrayed in a matrix along the XY plane. The repetition unit 20a includes a pixel section 22t corresponding to a pixel PE which is a unit for forming an image. The light-blocking member 21, the display member 22 and the pattern polarizing member 23 are bonded and fixed in a state of being arranged nearby with predetermined intervals therebetween. This makes it possible to make the device relatively thin. Note that the light-blocking member 21, the display member 22 and the pattern polarizing member 23 may be in close contact with each other. The arrangement of the display member 22 and the pattern polarizing member 23 is adjusted so that a polarization direction of the image light ML from the projection optical system 10 incident on the display member 22 via the pattern polarizing member 23 is the same as a polarization direction of the image light ML emitted in a wavelength-converting region 22e of the display member 22 and passing through the pattern polarizing member 23. Note that the pattern polarizing member 23 may be separated from the display member 22 in the optical axis AX direction, to cause the image light ML to be directly incident on the display member 22 from the projection optical system 10.
The polarization separation lens element 50 functions as a lens for the image light ML. The polarization separation lens element 50 is arranged at a face side, that is, the −Z side of the pattern polarizing member 23 of the composite display member 20 to cover the front of the eye. The polarization separation lens element 50 is an independent lens that collectively causes the plurality of pixels PE constituting the display member 22 to form an image. That is, the polarization separation lens element 50 collectively causes light corresponding to each pixel PE to form an image. By forming the polarization separation lens element 50 as an independent lens, an eye box can be easily enlarged. The polarization separation lens element 50 is a plate-like member that extends parallel to the XY plane. The polarization separation lens element 50 is specifically a liquid crystal lens 51, and includes a plurality of orbicular zones RA having circular shapes and different refractive index states, respectively. The orbicular zones RA in a group are concentrically arranged symmetrically about the optical axis AX. In the group of the orbicular zones RA, the orbicular zone RA in a periphery away from the optical axis AX has a width in a radial direction with the optical axis Ax as a center, which is smaller than that of the orbicular zone RA at a center through which the optical axis AX passes. In other words, the width of the orbicular zone RA in the radial direction is smaller as approaching the periphery.
The polarization separation lens element 50 acts on polarized light in a horizontal direction and does not act on polarized light in a perpendicular direction or the vertical direction. The polarization separation lens element 50 acting on the polarized light in the horizontal direction has a focal point at a display surface DS at which the wavelength-converting region 22e is formed or a position close thereto, or has refractive power comparable to a case in which the focal point is at the display surface DS or a position close thereto. Thus, the image light ML is emitted substantially parallel to the eye EY. As a result, an image and an external image are superimposed on the retina of the eye EY, and AR display can be performed.
As illustrated in
The second display optical system 103b is optically the same as the first display optical system 103a, or is obtained by inverting the first display optical system 103a horizontally. Thus, detail description thereof is omitted.
The light-blocking member 21 suppresses incidence of external light OL on the wavelength-converting region 22e of the display member 22. The light-blocking member 21 is obtained by providing a rectangular light-blocking layer 21b at a flat plate 21a that transmits light. As illustrated in
The light-blocking layer 21b is formed by light-absorbing paint or other substances that can be applied to a desired area by an ink-jet method, for example. A mold release pattern formed with a mold release agent is recorded in advance at a position at the flat plate 21a at which the light-blocking layer 21b is not formed. A spray containing light-absorbing substances is applied over the entire surface, and then the light-absorbing substances are removed at the position corresponding to the mold release pattern. With this, the light-blocking layer 21b may be made of the remaining light-absorbing substance layer. Paint having a color other than black may be used for the light-blocking layer 21b as long as substances contained therein have a light-absorbing action or a light-reflecting action. Moreover, a metal pattern is formed by using a photo-resist technique or the like at a position on the flat plate 21a at which the light-blocking layer 21b is to be formed, and the metal pattern is oxidized to improve an absorbing property. The light-blocking layer 21b may be thus formed. The light-blocking layer 21b may be a mirror made of a substance having reflectivity such as a metallic film. Note that the light-blocking layer 21b is not limited to one formed at the face side of the flat plate 21a and may be formed at the external side of the flat plate 21a.
The display member 22 illustrated in
The wavelength-converting region 22e emits fluorescence of any of red, green, or blue light by photoexcitation. In the embodiment, an example in which the image display panel 11 emits ultraviolet light as excitation light having a single wavelength will be described. In this case, since red light, green light, and blue light are emitted by ultraviolet light excitation, it is possible to prevent the blue light from being mixed with the red light and the green light.
The wavelength-converting region 22e includes a polygonal or circular outline in plan view. In addition, the wavelength-converting region 22e has a nanostructure that controls a direction of light.
The wavelength-converting region 22e includes a wavelength-converting layer 22f formed of a light-emitting material. The light-emitting material is a material that absorbs excitation light and emits light at a longer wavelength than that of the excitation light. Examples of the light-emitting material include inorganic phosphors, organic phosphors, organic fluorescent dyes, quantum dots, and the like. A quantum dot is a semiconductor fine particle having a diameter of 2 to 10 nanometers, and when excited by incident light, emits light of a color determined by the size and material of the particle. By using a light-emitting material that emits fluorescence, it is possible to increase luminance of the image light ML emitted from the display member 22.
The nanostructure of the wavelength-converting region 22e is formed by nanoimprint lithography, photolithography, or the like. The wavelength-converting layer 22f can be patterned by ink-jet printing, screen printing, or the like of a fluorescent material. Further, the wavelength-converting layer 22f can also be patterned by forming a mask and etching after spin coating of a fluorescent material. The nanostructure may be formed directly at the flat plate 22a, or at the wavelength-converting layer 22f.
Note that light scattering particles may be included in the wavelength-converting layer 22f to scatter the image light ML being fluorescence emitted from the display member 22 without providing the nanostructure at the wavelength-converting region 22e.
Of light with which the pixel display region 22p is irradiated, light incident on the wavelength-converting region 22e is reflected as fluorescence to the eye EY side, that is, forward, and light incident on a light-transmitting region A2 other than the wavelength-converting region 22e is transmitted or reflected and thus does not proceed to the eye EY side.
As illustrated in
The flat plate 22a being a substrate at which the wavelength-converting region 22e is provided is formed of glass or plastic that transmits light. At the flat plate 22a, the wavelength-converting region 22e corresponding to one sub-pixel PEa is formed in the pixel display region 22p. One wavelength-converting region 22e corresponds to any of red, green, and blue in one pixel of the image display panel 11 forming the sub-pixel PEa. The wavelength-converting region 22e has a one-to-one relationship with the sub-pixel PEa, and one wavelength-converting region 22e is irradiated with the sub-pixel spot SP corresponding to one sub-pixel PEa. The wavelength-converting region 22e is a region of the pixel section 22t which is equal to the light-blocking layer 21b or smaller than the light-blocking layer 21b. The sub-pixel spot SP is larger than the wavelength-converting region 22e, and has a size such that the sub-pixel spot SP does not enter the adjacent wavelength-converting region 22e. By controlling an irradiation state (angular direction or range) of light corresponding to each sub-pixel PEa from the projection optical system 10, it is possible to selectively emit the image light ML in the wavelength-converting region 22e.
As illustrated in
The pattern polarizing member 23 illustrated in
The pattern polarizing member 23 includes a first polarizing member 60 and a second polarizing member 70. The first polarizing member 60 includes, for example, a rectangular first polarizing region 23b at a flat plate 23a that transmits light. The first polarizing regions 23b are discretely provided corresponding to the wavelength-converting regions 22e. The second polarizing member 70 includes a second polarizing region 23c that restricts the external light OL to the second polarization direction different from the first polarization direction. The second polarizing region 23c is provided in a region of the flat plate 23a other than the first polarizing member 60, that is, other than the first polarizing region 23b. The pattern polarizing member 23 is obtained by integrally incorporating the first polarizing member 60 and the second polarizing member 70. That is, the first polarizing member 60 and the second polarizing member 70 are formed at the same substrate. The first polarizing regions 23b are arrayed on lattice points as illustrated in the
The pattern polarizing member 23 is, for example, a wire grid type polarizing plate and a fine grid made of metal such as aluminum is formed at the flat plate 23a made of glass or the like. The first polarizing region 23b and the second polarizing region 23c are patterned so that polarization directions are different by 90°. Note that it may also be possible to form only the first polarizing region 23b as a wire grid type polarizing plate, and to form the second polarizing region 23c by bonding an absorption-type polarizing film at the flat plate 23a. Here, the polarizing film is, for example, a resin sheet obtained by extending PVA with iodine adsorbed thereon in a specific direction.
The projection optical system 10 illustrated in
The image display panel 11 is a self-luminous image light generating device. The image display panel 11 is, for example, an organic electroluminescence (EL) display, and forms a single color still image or moving image on a two-dimensional display surface 11a. The image display panel 11 is driven by the display control device 88 to perform display operation. The image display panel 11 is not limited to the organic EL display, and can be replaced with a display device using inorganic EL, an organic LED, an LED array, a laser array, a quantum dot light emission element, or the like.
As illustrated in
As illustrated in
The liquid crystal lens 51 as the polarization separation lens element 50 includes a lens member 51a and a driving circuit 51c. The lens member 51a includes two light-transmitting substrates 53a and 53b facing each other, two electrode layers 54a and 54b provided on inner surface sides of the light-transmitting substrates 53a and 53b, and a liquid crystal layer 55 interposed between the electrode layers 54a and 54b. Not that, although not illustrated in the drawing, alignment films are arranged between the electrode layers 54a and 54b and the liquid crystal layer 55 to adjust an initial alignment state of the liquid crystal layer 55. The first electrode layer 54a includes a large number of electrodes 57 arranged concentrically along the XY plane in the orbicular zone RA, and the electrodes 57 are annular transparent electrodes. The large number of electrodes 57 are spaced apart from each other, and a lateral width of the electrode 57 located on an outer side is narrowed. The lateral width of the electrode 57 affects accuracy of a refraction action of the lens member 51a. Each electrode 57 is coupled to the driving circuit 51c via a wiring line 58 insulated by an insulating layer (not illustrated), on a route in the middle. The second electrode layer 54b is a common electrode extending parallel to the XY plane, and is uniformly formed along the light-transmitting substrate 53b. Different application voltages V1 to V7 are applied to the large number of electrodes 57 to adjust a distribution state of birefringence or retardation. When the liquid crystal lens 51 has an effect of a convex lens, the application voltage V1 is set higher than the application voltage V7, and the application voltages V2 to V6 are set to values gradually changed within a voltage range of V1 to V7.
A case in which the image light ML emitted from the display member 22 is incident on the liquid crystal lens 51 via the pattern polarizing member 23 and the like, in other words, a case in which horizontally polarized light (first polarized light P1) including a polarization plane parallel to the X direction is incident on the liquid crystal lens 51 is considered. With regard to the horizontally polarized light, a voltage applied to the electrode 57 that is arranged at the outermost side in the peripheral portion is increased to reduce retardation, and the refractive index is relatively reduced in the region. Thus, for example, in a case of light from a far point light source, the light that passes through the liquid crystal lens 51 via the electrode 57 in the peripheral portion has a wavefront that is relatively advanced. In contrast, a voltage applied to the electrode 57 that is arranged at the innermost side being the center portion is reduced to maintain retardation close to its original state, and the refractive index is relatively increased in the region. Thus, for example, in a case of light from a far point light source, the light that passes through the liquid crystal lens 51 via the electrode 57 in the center portion has a wavefront that is relatively delayed. Thus, image light ML0 in a diverging state that is incident on the liquid crystal lens 51 from an image RI set on a predetermined focal plane FP is horizontally polarized light, passes through the liquid crystal lens 51 to be subjected to an action as a convex lens, and becomes image light MLPR in a state in which a diverging angle is reduced. Virtual image light MLPI that traces back the image light MLPR is from a virtual image position farther than the focal plane FP. A focal length of the liquid crystal lens 51 is a distance from a point light source to the liquid crystal lens 51 when light from the point light source is collimated. In the embodiment, the focal length is substantially equal to a distance from the display member 22 to the liquid crystal lens 51. Approximately, with reference to the lens formula, the relationship expressed by 1/F=1/A+1/B is satisfied, where a distance from the focal plane FP to the liquid crystal lens 51 is A, a distance from the liquid crystal lens 51 to an image plane is B, and the focal length of the liquid crystal lens 51 is F.
Here, the distance B from the focal plane FP to the virtual image position is set to a distance as several times to several tens of times as long as the distance A from the liquid crystal lens 51 to the focal plane FP. Although detail description is omitted, the distance ratio corresponds to a magnification ratio of a virtual image. In the above, when a relative ratio of the application voltages V1 to V7 is substantially maintained so that the application voltages are set to be low, a difference in retardation between the center and the periphery decreases, and an absolute value of positive power of the liquid crystal lens 51 decreases. That is, the absolute value of the power can be increased by applying a high voltage VH to the liquid crystal lens 51, the absolute value of the power can be decreased by applying a low voltage VL to the liquid crystal lens 51, and the driving circuit 51c can cause the liquid crystal lens 51 to function as an externally adjustable varifocal lens.
The liquid crystal lens 51 functions as a varifocal lens to change the focal length F. Thus, the distance B from the liquid crystal lens 51 to the image plane position or the virtual image position can freely be changed, and adjustment of a magnification ratio can be performed. Further, even when visual acuity of the wearer US is imbalanced due to nearsightedness or the like, focus adjustment for observing a virtual image while maintaining a focused state can be performed. In other words, the image plane position or the virtual image position can be adjusted finely according to visual acuity of an individual (farsightedness, nearsightedness, astigmatism, or the like). The wearer US can perform adjustment of a magnification ratio or focus adjustment by operating the user terminal 90, for example. In other words, the virtual image display devices 100A and 100B enable customization relating to a magnification ratio and focus by an operation by the wearer US.
The liquid crystal lens 51 has an image formation action with respect to the image light ML being horizontally polarized light or vertically polarized light. The liquid crystal lens 51 may be regarded as a liquid crystal lens including a function as a lens with respect to a specific polarization component, and may also be regarded as a liquid crystal lens having a lens function acting on a specific polarization component. When the liquid crystal lens 51 is arranged in front of the eyes, an eye box having a size close to that of the liquid crystal lens 51 can be secured. The eye box can be increased in size, and chipping of an image is less likely to occur. Moreover, the display optical systems 103a and 103b that are reduced in size and have a large FOV can be achieved at the same time. Moreover, by combining the composite display member 20 including the display member 22, the pattern polarizing member 23, and the like, with the liquid crystal lens 51, display on a large screen can be performed with a small-sized optical system. Here, display on a large screen indicates a case in which a virtual image of 70 inches or larger is formed at a distance of 2.5 m ahead, for example.
The liquid crystal lens 51 does not need to be used with a variable focus but can be used with a fixed focus. The liquid crystal lens 51 is not limited to one in which retardation is gradually reduced from the center to the periphery, but may also be a Fresnel lens as disclosed, for example, in WO 2009/072670. The liquid crystal lens 51 may change an alignment direction of liquid crystal by ultrasonic waves.
Note that the external light OL that passes through the light-blocking member 21 and the like is the vertically polarized light (second polarized light P2), and even when the external light OL passes through the liquid crystal lens 51, retardation is kept uniform in the XY plane regardless of the values of the application voltages V1 to V7. Thus, a phase difference is not imparted, and the external light OL is not affected by a lens action of the liquid crystal lens 51. In other words, the external light OL linearly advances without being substantially affected by the composite display member 20 and the polarization separation lens element 50.
Referring to
In the above description, in the pattern polarizing member 23, the first polarization member 60 transmits only the image light ML being the horizontally polarized light, and the second polarizing member 70 transmits the external light OL being the vertically polarized light. However, the first polarizing member 60 may transmit the image light ML being the vertically polarized light, and the second polarizing member 70 may transmit the external light OL being the horizontally polarized light. With regard to the polarization separation lens element 50, it is necessary to change the polarization directions for the lens function accordingly as the function of the pattern polarizing member 23 is changed.
With reference to
The virtual image display devices 100A and 100B according to the first embodiment described above each include: the display member 22 including the wavelength-converting region 22e that emits fluorescence upon being excited by the image light ML as the pixel display region 22p, the projection optical system 10 that irradiates the wavelength-converting region 22e with the image light ML as excitation light having a single wavelength, the light-blocking member 21 arranged at the external side of the display member 22 for suppressing incidence of the external light OL on the wavelength-converting region 22e, the first polarizing member 60 arranged at the face side of the display member 22 and including the first polarizing region 23b provided corresponding to the wavelength-converting region 22e for restricting the image light ML displayed by the display member 22 to the first polarization direction, the second polarizing member 70 arranged at the external side of a position of the first polarizing member 60 and including the second polarizing region 23c for restricting the external light OL to the second polarization direction different from the first polarization direction, and the polarization separation lens element 50 arranged at the face side of the first polarizing member 60 and having refractive power that selectively acts on polarized light of the image light ML. Note that the second polarizing member 70 or the second polarizing region 23c may be arranged slightly away from a position of the first polarizing member 60 or the first polarizing region 23b toward the face side as long as control of polarization is not affected. Also in this case, it is considered that the second polarizing member 70 is arranged at the external side of the position of the first polarizing member 60.
In the virtual image display devices 100A and 100B described above, the transmitted light that passes through the light-blocking member 21 from the outside world is restricted to the second polarization direction via the second polarizing member 70, and passes through the polarization separation lens element 50 without being subjected to an action of refractive power. The image light ML that is emitted from the wavelength-converting region 22e is restricted to the first polarization direction via the first polarizing member 60, passes through the polarization separation lens element 50 while being subjected to an action of refractive power, and forms a virtual image. In this case, a virtual image corresponding to an image formed in the wavelength-converting region 22e of the display member 22 can be formed while the display member 22 and the polarization separation lens element 50 are arranged near the eye EY, and an angle of view can be increased without separating the display member 22 and the polarization separation lens element 50 to a large degree. In particular, the polarization separation lens element 50 is an independent lens, and hence an eye box can be enlarged. In addition, it is possible to reduce a load of the projection optical system 10 by setting the image light ML emitted from the projection optical system 10 to be monochromatic and displaying the display member 22 in color with fluorescence.
A virtual image display device according to a second embodiment will be described below. The virtual image display device according to the second embodiment is obtained by partially modifying the virtual image display device according to the first embodiment, and description of parts in common with those of the virtual image display device according to the first embodiment is omitted.
As illustrated in
Note that the projection optical system 10 according to the second embodiment can be used instead of the projection optical system 10 according to the first embodiment also in the virtual image display device 100A and the like according to third and subsequent embodiments.
A virtual image display device according to a third embodiment will be described below. The virtual image display device according to the third embodiment is obtained by partially modifying the virtual image display device according to the first embodiment, and description of parts in common with those of the virtual image display device according to the first embodiment is omitted.
As illustrated in
The second polarizing member 70 is obtained by boning a polarizing film 70b of an absorbing type at a flat plate 24a that transmits light. The polarizing film 70b is, for example, a resin sheet obtained by extending PVA with iodine adsorbed thereon in a specific direction. In the illustrated example, the polarizing film 70b only transmits vertically polarized light having a polarization plane parallel to the vertical ±Y direction, and absorbs horizontally polarized light having a polarization plane parallel to the horizontal ±X direction. As a result, of the external light OL, the horizontally polarized light is blocked by the second polarizing member 70, and the vertically polarized light passes through the second polarizing member 70. Note that the polarizing film 70b may block the first polarized light P1 by reflection. The polarizing film 70b that blocks polarized light by reflection is, for example, a wire grid type polarizing plate, and a fine grid made of metal such as aluminum is formed at the flat plate 24a made of glass or the like.
A virtual image display device according to a fourth embodiment will be described below. The virtual image display device according to the fourth embodiment is obtained by partially modifying the virtual image display device according to the first embodiment, and description of parts in common with those of the virtual image display device according to the first embodiment is omitted.
As illustrated in
Although omitted in illustration, at the entire optical array 25, a large number of the micro optical elements 25b are arrayed in a matrix along the XY plane. In other words, all the micro optical elements 25b constituting the optical array 25 are two-dimensionally arrayed periodically with respect to the horizontal X direction and the vertical Y direction. Each of the micro optical elements 25b is formed in a region corresponding to the sub-pixel PEa or the pixel PE in each of the repetition units 20a.
The micro optical element 25b is arranged in a vicinity of the display member 22, and hence the virtual image display device 100A can be easily reduced in thickness. In addition, by providing the microlens, a diffusion angle is further increased, and it is possible to increase an eye ring diameter when light is incident on the eye EY.
A virtual image display device according to a fifth embodiment will be described below. The virtual image display device according to the fifth embodiment is obtained by partially modifying the virtual image display device according to the first embodiment, and description of parts in common with those of the virtual image display device according to the first embodiment is omitted.
As illustrated in
The substrate SS is made of glass or plastic that transmits light, for example. In the composite display member 20, the light-blocking layer 21b is formed at the substrate SS by vapor deposition and etching, and the wavelength-converting region 22e is formed at the light-blocking layer 21b. The wavelength-converting region 22e is obtained by, for example, performing patterning by mask etching or patterning by printing.
The image light ML or the sub-pixel spot SP as excitation light projected from the projection optical system 10 as projected light MLe is incident on the wavelength-converting region 22e of the display member 22 through the discretely formed first polarizing region 23b of the pattern polarizing member 23. Image light MLf incident on the wavelength-converting region 22e is emitted in a direction in which the image light MLf is reflected as fluorescence, passes through the first polarizing region 23b again, and horizontally polarized light in the first polarization direction is incident on the polarization separation lens element 50.
Note that as illustrated in
A virtual image display device according to a sixth embodiment will be described below. The virtual image display device according to the sixth embodiment is obtained by partially modifying the virtual image display device according to the first embodiment, and description of parts in common with those of the virtual image display device according to the first embodiment is omitted.
As illustrated in
Although the present disclosure has been described with reference to the above-described embodiments, the present disclosure is not limited to the above-described embodiments and can be implemented in various modes without departing from the spirit of the disclosure. For example, the following modifications are possible.
In the embodiment described above, the liquid crystal lens 51 is not limited to one including the electrode as an element, and may be one having refractive power by filling a space between a Fresnel lens-like first substrate and a flat plate-like second substrate with liquid crystal and aligning the alignment of the liquid crystal with a Fresnel lens surface.
In the embodiment described above, the image light ML or the excitation light emitted from the projection optical system 10 is not limited to ultraviolet light, but may be blue light. In this case, as illustrated in
The liquid crystal lens 51 may include an elongated circular electrode that is slightly elongated in a specific direction, instead of a circular electrode.
The liquid crystal lens 51 as the polarization separation lens element 50 is not limited to a lens including the orbicular zone RA having a ring shape. As the polarization separation lens element 50, various structures having a lens action with respect to specific polarized light may be adopted.
Although it has been assumed above that the HMD 200 is worn on the head and is used, the virtual image display devices 100A and 100B may also be used as a hand-held display that is not worn on the head and is to be looked into like binoculars. In other words, the head-mounted display according to an aspect of the present disclosure also includes a hand-held display.
In the embodiment described above, the arrangement and size of the pixel PE or the sub-pixel PEa can be changed as appropriate so that a sufficient see-through region exists in one pixel.
A virtual image display device in a specific aspect includes: a display member including a wavelength-converting region that emits fluorescence upon being excited by image light as a pixel display region, a projection optical system that irradiates the wavelength-converting region with the image light as excitation light having a single wavelength, a light-blocking member arranged at the external side of the display member for suppressing incidence of external light on the wavelength-converting region, a first polarizing member arranged at the face side of the display member and including a first polarizing region provided corresponding to the wavelength-converting region for restricting the image light displayed by the display member to a first polarization direction, a second polarizing member arranged at the external side of a position of the first polarizing member and including a second polarizing region for restricting the external light to a second polarization direction different from the first polarization direction, and a polarization separation lens element arranged at the face side of the first polarizing member and having refractive power that selectively acts on polarized light of the image light.
In the virtual image display device described above, the transmitted light that passes through the light-blocking member from an outside world is restricted to the second polarization direction via the second polarizing member, and passes through the polarization separation lens element without being subjected to an action of refractive power. The image light that is emitted from the wavelength-converting region is restricted to the first polarization direction via the first polarizing member, passes through the polarization separation lens element while being subjected to an action of refractive power, and forms a virtual image. In this case, a virtual image corresponding to an image formed in the wavelength-converting region of the display member can be formed while the display member and the polarization separation lens element are arranged near an eye, and an angle of view can be increased without separating the display member and the polarization separation lens element to a large degree. In addition, it is possible to reduce a load of the projection optical system by setting the image light emitted from the projection optical system to be monochromatic and displaying the display member in color with fluorescence.
In a virtual image display device in a specific aspect, the excitation light is ultraviolet light, and the wavelength-converting region emits fluorescence of any of red light, green light, and blue light by ultraviolet light excitation. In this case, since red light, green light, and blue light are emitted by ultraviolet light excitation, it is possible to prevent the blue light from being mixed with the red light and the green light.
A virtual image display device in a specific aspect includes an ultraviolet radiation blocking member that absorbs or reflects ultraviolet light at the face side of a display region. In this case, it is possible to prevent the ultraviolet light from entering eyes of a wearer.
In a virtual image display device in a specific aspect, the excitation light is blue light, the display member includes a scattering region that scatters the blue light, and the wavelength-converting region emits fluorescence of any of red light and green light by blue light excitation. In the virtual image display device including the display member, the ultraviolet radiation blocking member is not necessary.
In a virtual image display device in a specific aspect, the display member includes the wavelength-converting region, and a light-transmitting region that enables visual recognition of an outside world.
In a virtual image display device in a specific aspect, the first polarizing regions are discretely provided corresponding to the wavelength-converting regions.
In a virtual image display device in a specific aspect, the light-blocking member includes a light-blocking layer that suppresses incidence of the external light, and the light-blocking layer has a size corresponding to that of the display region. In this manner, incidence of the external light on the display region can be further suppressed.
In a virtual image display device in a specific aspect, the first polarizing member and the second polarizing member are arranged at the same substrate, and the second polarizing region is arranged around the first polarizing region. Accordingly, it is possible to divide the first polarizing region and the second polarizing region in a planar manner, and it is possible to reduce the number of components while suppressing interference between the image light and the external light.
In a virtual image display device in a specific aspect, the polarization separation lens element is a polarization separation liquid crystal lens that causes a plurality of pixels constituting the display member to collectively form an image. With an independent lens, an eye box can be enlarged.
In a virtual image display device in a specific aspect, the projection optical system includes an image display panel that displays an image, and projects light emitted from a light-emitting region of the image display panel onto the pixel display region as the image light. That is, an image on the image display panel is projected onto the corresponding pixel display region, and an image to be displayed is formed on the display member.
In a virtual image display device in a specific aspect, the projection optical system projects modulated light from a laser light source onto the pixel display region as the image light, by a micro mirror driven for scanning. In other words, a locus along which the modulated light moves on the display member by the scanning corresponds to an image to be displayed.
In a virtual image display device in a specific aspect, the light-blocking member, the display member, and the first polarizing member are integrated. Accordingly, it is possible to reduce the device in thickness and weight.
In a virtual image display device in a specific aspect, the display member includes a wavelength-converting region for red fluorescence, a wavelength-converting region for green fluorescence, and a wavelength-converting region for blue fluorescence, and includes a light-transmitting region that transmits the external light in a region where the wavelength-converting region is not arranged.
According to a specific aspect, a head-mounted display apparatus includes a first device including the virtual image display device described above, a second device including the virtual image display device described above, and a support device including a temple supporting the first device and the second device, the temple being configured to enable mounting of the first device and the second device on a head.
Number | Date | Country | Kind |
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2023-006815 | Jan 2023 | JP | national |