Patent Application
20220066219
The present application is based on, and claims priority from JP Application Serial Number 2020-144248, filed Aug. 28, 2020, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a see-through type virtual image display device and an optical unit, and particularly relates to a type of a virtual image display device and an optical unit that allow imaging light to enter a concave transmission mirror and observe reflected light from the concave transmission mirror.
As a virtual image display device, a so-called bird bath type device including a transmissive reflection surface and a concave transmission mirror is known (see JP-A-2020-008749). JP-A-2020-008749 describes a feature wherein the imaging light incident on a prism member provided with the transmissive reflection surface is guided by total internal reflection toward the transmissive reflection surface on the total reflection surface of the prism member, as well as the imaging light is reflected by the transmissive reflection surface toward the concave transmission mirror disposed in front of the prism member.
In the virtual image display device of JP-A-2020-008749, the imaging light is emitted to a front face, and therefore, there is a problem in that the image being displayed is visible from the outside.
A virtual image display device according to one aspect of the present disclosure includes an imaging light generation device, and an optical unit including a concave transmission mirror provided with a partial reflection film, the optical unit being configured to form a virtual image with the imaging light emitted from the imaging light generation device, wherein the optical unit includes a reflection type diffraction element disposed on an external side of the partial reflection film, the reflection type diffraction element being configured to diffract the imaging light so that the imaging light is deviated from an optical path passing through the concave transmission mirror.
Hereinafter, a virtual image display device according to a first embodiment of the present disclosure and an optical unit incorporated therein will be described with reference to
The HMD 200 includes a first display device 100A for the right eye, a second display device 100B for the left eye, and a pair of temple support devices 100C for supporting the display devices 100A and 100B. The first display device 100A includes a display driving unit 102 disposed at an upper portion, and an appearance member 105 that has a spectacle lens shape and covers the front of the eye. Similarly, the second display device 100B includes a display driving unit 102 disposed at an upper portion, and an appearance member 105 that has a spectacle lens shape and covers the front of the eye. The support device 100C supports a top end side of the appearance member 105 via the display driving unit 102. The first display device 100A and the second display device 100B are optically inverted from left to right. Hereinafter, the first display device 100A for the right eye will be described as the representative virtual image display device 100.
A virtual image display device 100, which is the display device 100A for the right eye, will be described with reference to
The imaging light generation device 11 is a self-emitting display device. The imaging light generation device 11 is, for example, an organic EL (Organic Electro-Luminescence) display, and forms a color still image or a moving image on a two-dimensional display surface 11a. The imaging light generation device 11 is driven by the display control circuit 13 to perform display operation. The imaging light generation device 11 is not limited to organic EL displays, and can be replaced with display devices using inorganic ELs, LED arrays, organic LEDs, laser arrays, quantum dot light-emitting elements, etc. The imaging light generation device 11 is not limited to the self-emitting imaging light generation device, and may include an LCD or another light modulating element, and may form an image by illuminating the light modulating element with a light source such as a backlight. As the imaging light generation device 11, a LCOS (Liquid crystal on silicon, where LCoS is a registered trademark), a digital micro-mirror device, etc. may be used instead of the LCD.
The optical unit 12 is an imaging system including a projection lens 21, a transmission inclined mirror 23, and a concave transmission mirror 24. The optical unit 12 images imaging light ML emitted from the imaging light generation device 11 as a virtual image. In the optical unit 12, an optical path from the imaging light generation device 11 to the projection lens 21 is located on the upper side of the transmission inclined mirror 23. More specifically, the imaging light generation device 11 and the projection lens 21 are disposed in a space interposed between an inclined plane in which the transmission inclined mirror 23 is extended and a vertical surface in which an upper end of the concave transmission mirror 24 is extended upward.
The projection lens 21 is held within the outer frame of the display driving unit 102 illustrated in
The transmission inclined mirror 23 is a flat plate shaped optical member, and has a planar reflection surface MS. The word of transmission in the transmission inclined mirror 23 means that light is partially transmitted. The transmission inclined mirror 23 is formed of a metal film or a dielectric multilayer film as a transmissive reflection film on an inner side surface 23r of a parallel flat plate 23a having a uniform thickness and transparency. Such a transmissive reflection film functions as a planar reflection surface MS. The reflectance and the transmittance of the planar reflection surface MS are set to, for example, approximately 50%. An antireflection film can be formed at an outer side surface 23f of the parallel flat plate 23a.
The transmission inclined mirror 23 bends an optical axis AX in a direction orthogonal to the optical axis AX in the YZ plane. The imaging light ML traveling downward through the projection lens 21 is bent in the +Z direction, that is the front direction, by the transmission inclined mirror 23, and is incident on the concave transmission mirror 24. The transmission inclined mirror 23 is disposed between the concave transmission mirror 24 and the exit pupil EP on which the eye EY or a pupil is located. The transmission inclined mirror 23 covers the exit pupil EP. The transmission inclined mirror 23 can be fixed directly or indirectly to the outer frame of the display driving unit 102 illustrated in
The concave transmission mirror 24 is an optical member having a concave shape toward the exit pupil EP. The word of transmission in the concave transmission mirror 24 means that light is partially transmitted. The concave transmission mirror 24 has a light convergence function as a function for imaging, and performs collimation by reflecting the imaging light ML that is reflected by the transmission inclined mirror 23 and travels forward while being diverging. The imaging light ML is returned to the transmission inclined mirror 23 by the concave transmission mirror 24, and is partially transmitted through the transmission inclined mirror 23 and is collected into the exit pupil EP. That is, the concave transmission mirror 24 reflects the imaging light ML so that the imaging light ML is collected into the exit pupil EP while being collimated by a partial reflection film 24b that is concave inside. At this time, the imaging light ML is incident from a direction close to normal to the entire portion of a partial reflection surface MC of the concave transmission mirror 24, and then reflected, whereby the optical symmetry thereof is high. A plate shaped body 24a of the concave transmission mirror 24 has a uniform thickness while being curved. The plate shaped body 24a has transparency that allows light to be transmitted substantially without loss. A metal film or a dielectric multilayer film is formed as a partial reflection film on an inner surface 24r of the plate shaped body 24a. Such a partial reflection film functions as a concave partial reflection surface MC. The reflectance and transmittance of the partial reflection surface MC are set to, for example, approximately 20˜50%. The partial reflection surface MC ensures optical transparency of the concave transmission mirror 24 with respect to external light OL etc. A reflection type diffraction layer that diffracts the imaging light ML is formed at an outer side surface 24f of the plate shaped body 24a. Such a reflection type diffraction layer functions as a reflection type diffraction element DD. The reflection type diffraction element DD ensures blocking of the concave transmission mirror 24 with respect to the imaging light ML. The reflection type diffraction element DD exerts functions thereof by being disposed on the external side of the partial reflection film that forms the partial reflection surface MC. Here, the reflection type diffraction element DD is formed as part of the concave transmission mirror 24 so that a surface on an external side of the concave transmission mirror 24 is formed. In this case, a number of parts can be reduced and an increase in the weight and price of the device can be suppressed. Note that an antireflection film can be formed at the surface of the reflection type diffraction element DD.
The partial reflection surface MC may be a free curved surface, while it is easy to have the target reflection characteristics of the partial reflection surface MC by providing an axisymmetric curved surface such as a spherical surface or an aspheric surface.
The concave transmission mirror 24 is incorporated to constitute a portion of the transmissive appearance member 105 illustrated in
The concave transmission mirror 24 or plate shaped body 24a preferably has a thickness of 1 mm or greater in order to ensure shape strength, but preferably has a thickness of 2 mm or less in terms of weight reduction. The plate shaped body 24a is formed from a resin material having optical transparency, for example, by injection molding.
In describing the optical path, the imaging light ML from the imaging light generation device 11 is incident on the transmission inclined mirror 23 via the projection lens 21. An intermediate image (not illustrated), which is an appropriately enlarged image formed at the display surface 11a of the imaging light generation device 11, may be formed between the transmission inclined mirror 23 and the projection lens 21. The imaging light ML incident on the transmission inclined mirror 23 and reflected by the planar reflection surface MS by, for example, approximately 50%, is incident on the concave transmission mirror 24 and is reflected by the partial reflection surface MC, for example, at a reflectance of approximately 50% or less. The imaging light ML reflected by the concave transmission mirror 24 is transmitted through the transmission inclined mirror 23, and is incident on the exit pupil EP on which the eye EY or the pupil of the wearer US is located. Here, the exit pupil EP is an eye point of the optical unit 12 assuming that the eye EY is located. Light from each point of the display surface 11a of the imaging light generation device 11 is incident to be collected at a certain point of the exit pupil EP at an angle that allows for the observation of the virtual image. The external light OL passing through the concave transmission mirror 24 is also incident on the exit pupil EP. In other words, the wearer US wearing the HMD 200 can observe the virtual image with the imaging light ML by overlaying the virtual image on the external image.
Note that the concave transmission mirror 24 causes the external light OL to pass therethrough, but also causes the imaging light ML to pass therethrough, which result in the passing light LP in front of the concave transmission mirror 24. If the intensity of the passing light LP is large, a third party OS present around the wearer US can observe a portion PI of the image displayed on the display surface 11a of the imaging light generation device 11 (see
Hereinafter, the structure of the concave transmission mirror 24 will be described below with reference to
The reflection type diffraction layer 24c or the reflection type diffraction element DD includes an R diffraction layer 41a that diffracts red R light, a G diffraction layer 41b that diffracts green G light, and a B diffraction layer 41c that diffracts blue B light as the three diffraction elements corresponding to the three colors. The R diffraction layer 41a diffracts the R component LE1 of the leakage light LE, deflects the component away from the original optical path, and forms a red wavelength diffraction light LD emitted in the downward direction. The G diffraction layer 41b diffracts the G component LE2 of the leakage light LE, deflects the component away from the original optical path, and forms a green wavelength diffraction light LD emitted in the downward direction. The B diffraction layer 41c diffracts the B component LE3 of the leakage light LE, deflects the component away from the original optical path, and forms a blue wavelength diffraction light LD emitted in the downward direction. The R diffraction layer 41a, the G diffraction layer 41b, and the B diffraction layer 41c are reflection type diffraction elements, respectively. They are individually manufactured as film-shaped optical elements, joined to each other and laminated, and attached to the outer side surface 24f of the plate shaped body 24a as a whole to form the external side surface. Each of the diffraction layers 41a, 41b, and 41c is, for example, a volume hologram element. When each of the diffraction layers 41a, 41b, and 41c is a volume hologram element, the reflection type diffraction element DD includes three diffraction layers 41a, 41b, 41c as three volume hologram layers corresponding to the three colors. In this case, the diffraction layers 41a, 41b, and 41c are produced by a technique such as irradiating a film shaped storage material with object light and reference light to interfere with each other in the storage material for exposure and recording.
Note that the partial reflection film 24b need not be formed directly at the plate shaped body 24a. For example, the plate shaped body 24a may be coated with a hard coat film, and the partial reflection film 24b may be formed thereon. The reflection type diffraction layer 24c also need not be formed directly at the plate shaped body 24a or directly affixed thereon. For example, the plate shaped body 24a may be coated with a hard coat film, and the reflection type diffraction layer 24c may be formed or affixed thereon. Furthermore, the partial reflection film 24b may be embedded in the plate shaped body 24a.
The reflection type diffraction element DD need not have a three-layer structure including the R diffraction layer 41a, the G diffraction layer 41b, and the B diffraction layer 41c, but may be an element in which stripes that diffract the imaging light ML or the leakage light LE for each color of RGB may be collectively formed in a single layer. In this manner, when the RGB imaging light ML or the leakage light LE is diffracted in a single layer, it is expected that the diffraction efficiency is reduced and some drop light is generated at the peak wavelength compared to a case where the three diffraction layers 41a, 41b, 41c are incorporated therein. However, when the light intensity of such drop light is not large, it will not be easy for the third party to observe the image in the display. Conversely, the reflection type diffraction element DD may have a multilayer structure with three or more layers. For example, in addition to the diffraction layers 41a, 41b, 41c described above, a fourth diffraction layer that diffracts the imaging light ML in the wavelength range between RG and a fifth diffraction layer that diffracts the imaging light ML in the wavelength range between GB can be added to obtain a reflection type diffraction element DD having a five-layer structure. In this case, the imaging light ML used in the range of wavelengths between RG or between GB can be prevented from being emitted to the external side of the concave transmission mirror 24 and being observable to the third party.
In the above, the reflection type diffraction layer 24c is configured to propagate the imaging light ML or the leakage light LE to be reflected or bent downward so that the imaging light ML or the leakage light LE is deviated from the linear optical path passing through the concave transmission mirror 24. Meanwhile, the imaging light ML or the leakage light LE may be propagated to be reflected or bent upward from the original optical path. Here, the “upward” refers to the inner side or the exit pupil EP side of the reflection type diffraction layer 24c in a conical region extending above 45° or less with respect to the upper side of the incident point or the +Y side, along an intersection line between the tangent plane of the reflection type diffraction layer 24c at the incident point of the leakage light LE and a surface parallel to the YZ plane. In this case, an absorbent material for absorbing the diffraction light LD can be applied or adhered to the edge of the upper end of the concave transmission mirror 24. The three diffraction layers 41a, 41b, and 41c need not diffract each color light of RGB in the same direction. One of the colors may be diffracted upward and the remaining color may be diffracted downward. The three diffraction layers 41a, 41b, and 41c need not have the same diffraction efficiency. For example, the G diffraction layer 41b having a high relative luminous efficiency can be relatively increased in diffraction efficiency.
The reflection type diffraction layer 24c may propagate the imaging light ML or the leakage light LE to be reflected or bent in the left-right lateral direction or the oblique direction of the concave transmission mirror 24. Here, the “lateral direction” refers to the inner side or the exit pupil EP side of the reflection type diffraction layer 24c in a conical region within 45° or less with respect to the ±X side of the incident point, along an intersection line between the tangent plane of the reflection type diffraction layer 24c at the incident point of the leakage light LE and a surface parallel to the YZ plane. In this case, an absorbent material for absorbing the diffraction light LD can be applied or adhered to the edge of the right end or the left end of the concave transmission mirror 24. However, when the diffraction angle of the leakage light LE increases in the lateral direction, the proportion of the diffraction light LD emitted from the inner surface of the concave transmission mirror 24 toward the side of the concave transmission mirror 24 is increased. To avoid this, it may also be desirable to provide a light shielding member that overhangs the face side at the left and right ends of the concave transmission mirror 24 so that the virtual image cannot be observed by the third party located on the side of the wearer US. Note that the oblique direction refers to the intermediate direction between the lateral direction and the vertical direction. The oblique direction refers to, for example, the inner side or the exit pupil EP side of the reflection type diffraction layer 24c in an intermediate direction between the +X direction and the +Y direction, and in a conical region within 45° of the intermediate direction.
As described above, according to the virtual image display device 100 of the first exemplary embodiment, the reflection type diffraction element DD diffracts the imaging light ML so that the imaging light ML is deviated from the optical path passing through the concave transmission mirror 24, whereby the imaging light ML emitted to the external side through the partial reflection film 24b can be suppressed, and the image in the display is made less visible from the outside, and the effect of suppressing information loss increases.
In the virtual image display device 100 of the present exemplary embodiment, the reflection type diffraction element DD diffracts the imaging light ML upward or downward. A situation where the third party is present above or below the virtual image display device 100 is unlikely to occur, and the light shielding member is easily disposed above or below the virtual image display device 100, whereby the effect of suppressing information loss can be further enhanced.
Hereinafter, a virtual image display device according to a second exemplary embodiment will be described. Note that the virtual image display device according the second exemplary embodiment is obtained by modifying a part of the virtual image display device according to the first exemplary embodiment, and description on common portions is omitted.
In the example illustrated in
Hereinafter, a virtual image display device according to a third exemplary embodiment will be described. Note that the virtual image display device according the third exemplary embodiment is obtained by modifying a part of the virtual image display device according to the first exemplary embodiment, and description on common portions is omitted.
In the above, the narrow band light source 311a may be a narrow-band light source such as an LED. The scanner 311b may also rotate the two mirrors 15 about non-parallel axes. Furthermore, a relay lens for adjusting the state of the luminous flux or a pupil enlarging member for enlarging the luminous flux size of the imaging light ML can be disposed after the scanner 311B.
Hereinafter, a virtual image display device according to a fourth exemplary embodiment will be described. Note that the virtual image display device according the fourth exemplary embodiment is obtained by modifying a part of the virtual image display device according to the first exemplary embodiment, and description on common portions is omitted.
Hereinafter, a virtual image display device according to a fifth exemplary embodiment will be described. Note that the virtual image display device according the fifth exemplary embodiment is obtained by modifying a part of the virtual image display device according to the first exemplary embodiment, and description on common portions is omitted.
A virtual image display device according to the fifth exemplary embodiment will be described with reference to
The folding mirror 22 includes a first mirror 22a and a second mirror 22b in an optical path from the imaging light generation device 11. The folding mirror 22 reflects the imaging light ML from the projection lens 21 in the intersecting direction. The transmission inclined mirror 23 is disposed on the light exit side of the second mirror 22b. A projection optical axis AX0, which is an optical axis of the projection lens 21, extends parallel to the horizontal X-axis direction. The optical path is bent along the reflective optical axis AX1 from the projection optical axis AX0 by the first mirror 22a, and the optical path is bent along the reflective optical axis AX2 from the reflective optical axis AX1 by the second mirror 22b. As a result, the optical axis extending in a substantially horizontal direction on the exit side of the projection lens 21 extends in a direction close to the vertical at the incident side of the transmission inclined mirror 23.
The transmission inclined mirror 23 is inclined at an angle θ=20˜40° in a counterclockwise direction about the X axis when viewed from the −X side with respect to the XY plane extending in the vertical direction. The optical path from the imaging light generation device 11 to the folding mirror 22 is disposed on the upper side of the transmission inclined mirror 23. More specifically, the imaging light generation device 11, the projection lens 21, and the folding mirror 22 disposed in a space interposed between an inclined plane in which the transmission inclined mirror 23 is extended and a vertical surface in which an upper end of the concave transmission mirror 24 is extended upward.
As described above, the transmission inclined mirror 23 is inclined at an angle θ=20˜40° in a counterclockwise direction about the X axis when viewed from the −X side, based on the XY plane as described above. In other words, the transmission inclined mirror 23 is disposed so that the angle formed by the Y axis, which is the vertical axis, and the transmission inclined mirror 23, is less than 45°. If the angle formed by the Y axis and the transmission inclined mirror 23 is greater than 45°, the transmission inclined mirror 23 is in a state of being tipped more than the standard, and the thickness of the transmissive mirror in the Z-axis direction increases. Meanwhile when the angle formed by the Y axis and the transmission inclined mirror 23 is less than 45°, the transmission inclined mirror 23 is in a state of rising more than the standard, and the thickness of the transmissive mirror in the Z-axis direction decreases. In other words, by making the angle formed by the Y axis and the transmission inclined mirror 23 less than 45° as in the present exemplary embodiment, it is possible to avoid the transmission inclined mirror 23 from being disposed to protrude greatly in the −Z direction of the back surface with respect to the concave transmission mirror 24, whereby avoiding an increase in the thickness of the virtual image display device 100 or the optical unit 512 in the front-rear direction in the Z direction.
In the optical unit 512, the cross-sectional structure of the concave transmission mirror 24 is the same as that illustrated in
Hereinafter, a virtual image display device according to a sixth exemplary embodiment will be described. Note that the virtual image display device according the sixth exemplary embodiment is obtained by modifying a part of the virtual image display device according to the first exemplary embodiment, and description on common portions is omitted.
As illustrated in
Hereinafter, an overview of the optical path of the imaging light ML will be described. The light-guiding member 31 guides the imaging light ML emitted from the projection lens 21 toward the observer's eyes by reflection on the first to fifth surfaces S11 to S15. Specifically, the imaging light ML from the projection lens 21 is first incident on the fourth surface S14 and reflected by the fifth surface S15, which is the inner surface of the reflection film RM. The imaging light ML is incident again from the inner side on the fourth surface S14 and is totally reflected. Then the imaging light ML is incident on and totally reflected by the third surface S13, and is incident on and totally reflected by the first surface S11. The imaging light ML totally reflected by the first surface S11 is incident on the second surface S12, is partially reflected while partially passing through the partial reflection surface MC, i.e. a partial reflection film, provided at the second surface S12. Then the imaging light ML is incident again on the first surface S11 and passes therethrough. The imaging light ML that has passed through the first surface S11 is incident on the exit pupil EP where the observer's eyes are located as a substantially parallel luminous flux. That is, the observer observes the image by the imaging light ML as a virtual image.
The optical unit 612 causes the observer visually recognize the imaging light ML by the light-guiding member 31, and causes the observer to observe the external image with little distortion in a state where the light-guiding member 31 and the light transmission member 32 are combined. At this time, since the third surface S13 and the first surface S11 are flat surfaces substantially parallel to each other (diopter is approximately 0), almost no aberration etc. occurs in the external light OL. Further, similarly, the third transmission surface 23 and the first transmission surface S21 are flat surfaces that are substantially parallel to each other. Furthermore, since the third transmission surface S23 and the first surface S11 are flat surfaces that are substantially parallel to each other, almost no aberration etc. occurs. As described above, the observer observes the external image without distortion through the light transmission member 32.
Hereinafter, a virtual image display device according to a seventh exemplary embodiment will be described. Note that the virtual image display device according the seventh exemplary embodiment is obtained by modifying a part of the virtual image display device according to the first exemplary embodiment, and description on common portions is omitted.
Referring to
The present disclosure is described according to the above-mentioned exemplary embodiments, but the present disclosure is not limited to the above-mentioned exemplary embodiments. The present disclosure may be carried out in various modes without departing from the gist of the present disclosure, and, for example, the following modifications may be carried out.
The optical unit 12 can be an optical system that does not include the projection lens 21. In this case, the optical system collimates the display image formed at the display surface 11a of the imaging light generation device 11 by the concave transmission mirror 24.
The plate shaped body 24a that constitutes the concave transmission mirror 24 is not limited to a resin material, and may be formed from glass, synthetic quartz, or a composite of these material and a resin material.
The optical unit 12 may be an optical system including a light guide, a prism, a composite of a prism and a mirror, etc. before the transmission inclined mirror 23.
A virtual image display device according to a specific aspect includes an imaging light generation device, and an optical unit including a concave transmission mirror provided with a partial reflection film, the optical unit being configured to form a virtual image with the imaging light emitted from the imaging light generation device, wherein the optical unit includes a reflection type diffraction element disposed on an external side of the partial reflection film, the reflection type diffraction element being configured to diffract the imaging light so that the imaging light is deviated from an optical path passing through the concave transmission mirror.
In the above-described virtual image display device, the reflection type diffraction element diffracts the imaging light so that the imaging light is deviated from the optical path passing through the concave transmission mirror, whereby the imaging light emitted to the external side through the partial reflection film can be suppressed, and the image in the display is made less visible from the outside, and the effect of suppressing information loss increases.
In a specific aspect, the reflection type diffraction element diffracts the imaging light upward or downward. A situation where the third party is present above or below the virtual image display device is unlikely to occur, and the light shielding member is easily disposed above or below the virtual image display device 100, whereby the effect of suppressing information loss can be further enhanced.
In another aspect, the reflection type diffraction element is formed as part of the concave transmission mirror on the surface on an external side of the concave transmission mirror. In this case, a number of parts can be reduced and an increase in the weight and price of the device can be suppressed.
In yet another aspect, the reflection type diffraction element is formed at the cover disposed on the external side of the concave transmission mirror. In this case, manufacturing and incorporation of the reflection type diffraction element is facilitated.
In yet another aspect, the cover has transparency to the external light between the wavelength ranges of respective colors of the imaging light.
In yet another aspect, the cover is formed in a region covering an effective region of the concave transmission mirror.
In yet another aspect, the reflection type diffraction element is the volume hologram element. The volume hologram element is highly controllable to the imaging light and has a high degree of freedom in design for the transparency of the external light.
In yet another aspect, the volume hologram element includes the three volume hologram layers corresponding to the three colors. In this case, the diffraction efficiency for each three colors can be increased, whereby the effect of suppressing passing light emitted to the external side through the concave transmission mirror is enhanced.
In yet another aspect, the reflection type diffraction element includes a the wavelength-limiting filter that modifies the wavelength distribution of the imaging light in accordance with the wavelength characteristics of the reflection type diffraction element. In this case, the characteristics of the imaging light incident on the wavelength-limiting filter are easily matched to the diffraction characteristics of the reflection type diffraction element, whereby the reliability of preventing information loss is enhanced.
In yet another aspect, the wavelength-limiting filter is provided in association with the imaging light generation device. In this case, since the external light is not attenuated by the wavelength-limiting filter, it is possible to suppress a decrease in see-through properties.
In yet another aspect, the wavelength-limiting filter is disposed between the substrate and the reflection type diffraction element in the concave transmission mirror.
In yet another aspect, the imaging light generation device includes the light source that emits the narrow band light.
In yet another aspect, the imaging light generation device includes the scanner that scans the laser light emitted from a laser source that is the light source.
In yet another aspect, the concave transmission mirror reflects the imaging light to collect the imaging light into the exit pupil.
In yet another aspect, the optical unit includes the transmission inclined mirror that reflects the imaging light from the imaging light generation device, and the concave transmission mirror reflects the imaging light reflected by the transmission inclined mirror toward the transmission inclined mirror. In this case, the transmission inclined mirror is disposed covering the front of the eye, and the concave transmission mirror is disposed covering the transmission inclined mirror.
An optical unit according to a specific aspect including a concave transmission mirror provided with a partial reflection film, the optical unit being configured to form a virtual image with imaging light, the optical unit includes a reflection type diffraction element disposed on an external side of the partial reflection film, the reflection type diffraction element being configured to diffract the imaging light so that the imaging light is deviated from an optical path passing through the concave transmission mirror.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-144248 | Aug 2020 | JP | national |
