JPWO2017056802A1 - Image projection device - Google Patents

Abstract

A scanning unit that scans a light beam emitted from a light source in a two-dimensional direction, an optical component that reflects or transmits the light beam scanned by the scanning unit, and the optical component that is disposed in front of a user's eyeball and is incident from a lateral direction And a first mirror 24 that projects an image on the retina by reflecting the reflected or transmitted light beam and irradiating the retina of the eyeball, and the first mirror includes the first region R1 and the second region. The first mirror of the first mirror is located in a direction in which the light beam is incident from the second region, and the optical component is the first region of the light beam scanned by the scanning unit. The condensing power in the third region S1 that reflects or passes the first light beam L1 applied to the second light beam L2 that reflects or passes the second light beam L2 applied to the second region among the light beams scanned by the scanning unit. Image projection apparatus to be larger than the condensing power in the region S2.

Description

  The present invention relates to an image projecting apparatus, and more particularly to an image projecting apparatus that projects an image directly onto a user's retina.

  An image projection apparatus such as a head-mounted display (HMD) that directly projects an image onto a user's retina using light emitted from a light source is known (Patent Document 1). In such an image projection apparatus, a method called Maxwell's view is used. In Maxwell's view, light rays that form an image are focused near the pupil, and the image is projected onto the retina.

  An image projection apparatus that detects light reflected by the cornea so that the light beam is focused on the retina and adjusts the focus position is known (Patent Document 2). In addition, there is known an image projection apparatus in which light emitted from a light source is reflected by two mirrors having different curvatures in a plane and irradiated to a user's retina (Patent Documents 3 and 4).

International Publication No. 2014/192479 JP 2009-258686A JP 2008-46253 A International Publication No. 2004/029693

  When a mirror is disposed in front of the user's eye and the light beam forming the image for Maxwell's viewing is focused near the pupil, a region in which the in-focus position greatly deviates from the retina occurs in the image. For example, when trying to adjust the in-focus position by a method as in Patent Document 2, the in-focus position is adjusted in synchronization with the scanning light beam to form an image. However, the focus adjustment can be performed at high speed. difficult.

  The present invention has been made in view of the above problems, and an object of the present invention is to set an in-focus position to an appropriate position.

  The present invention includes a scanning unit that scans a light beam emitted from a light source in a two-dimensional direction, an optical component that reflects or transmits the light beam scanned by the scanning unit, and an optical component that is disposed in front of a user's eyeball. A first mirror for projecting an image on the retina by reflecting the reflected or transmitted light beam and irradiating the retina of the eyeball, and the first mirror has a first region and a second region. In the first mirror, the first region is positioned in a direction in which the light beam is incident from the second region, and the optical component irradiates the first region of the light beam scanned by the scanning unit. The condensing power in the third region that reflects or passes one light beam is greater than the condensing power in the fourth region that reflects or passes the second light beam irradiated to the second region among the light beams scanned by the scanning unit. big An image projection apparatus characterized by.

  In the above configuration, the first distance between the first position where the first light beam is focused and the retina, and the second distance between the second position where the second light beam is focused and the retina are respectively: It can be set as the structure smaller than the said 1st distance and the said 2nd distance when it is assumed that the condensing power in the said 3rd area | region and the said 4th area | region is the same.

  In the above configuration, the optical component may be a second mirror, and the curvature of the second mirror in the third region may be larger than the curvature of the second mirror in the fourth region.

  In the above configuration, the optical component may be a diffraction grating, and the pitch of the diffraction grating in the third region may be larger than the pitch of the diffraction grating in the fourth region.

  The said structure WHEREIN: The condensing power of the said 1st mirror in the said 1st area | region can be set as the structure smaller than the condensing power of the said 1st mirror in the said 2nd area | region.

  In the above-described configuration, the first region and the second region may be positioned on both sides in the light incident direction with respect to a position corresponding to the center of the image in the first mirror. it can.

  In the above configuration, a distance between the first region and the second region in the first mirror may be larger than a distance between the third region and the fourth region in the optical component.

  In the above configuration, the optical corresponding to a pair of positions in the first mirror that is symmetrical with respect to a line extending in a direction in which the light ray passes through a position corresponding to the center of the image in the first mirror. The condensing power at a pair of positions in the component may be substantially equal.

  The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image light beam, a reflection mirror that reflects the image light beam scanned by the scanning mirror, and the image light beam reflected by the reflection mirror is projected onto the retina of the user's eyeball A projection mirror, wherein the surface of the projection mirror has a free-form surface, and the surface of the reflection mirror has a free-form surface corresponding to a change in curvature of the free-form surface of the projection mirror.

  The said structure WHEREIN: The free-form surface of the said reflective mirror can be set as the structure containing a concave curved surface and a convex curved surface.

  In the above-described configuration, the free-form surface of the projection mirror has regions with different curvatures, and image light beams reflected by the concave and convex curved surfaces of the reflection mirror are respectively irradiated on the different regions of the projection mirror and reflected by the concave surface. The concave image of the reflecting mirror and the concave surface of the reflecting mirror are irradiated so that the projected image light beam is irradiated to the region of the projection mirror having a smaller curvature than the curvature of the region of the projection mirror irradiated with the image light beam reflected by the convex curved surface. It can be set as the structure by which the convex curved surface is set.

  The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image light beam, a reflection mirror that reflects the image light beam scanned by the scanning mirror, and the image light beam reflected by the reflection mirror is projected onto the retina of the user's eyeball A projection mirror, wherein the surface of the projection mirror has a free-form surface, and the reflection mirror includes a reflective diffraction element corresponding to a change in curvature of the free-form surface of the projection mirror.

  The said structure WHEREIN: The said reflection type diffraction element can be set as the structure which has phase distribution from which a phase pitch differs.

  In the above configuration, the free-form surface of the projection mirror has regions with different curvatures, and the image light beams reflected by the reflective diffraction element having a wide phase pitch region and a narrow phase pitch region have different curvatures of the projection mirror. The image light beam irradiated to each region and reflected by the region having a large phase pitch is projected with a smaller curvature than the curvature of the region of the projection mirror irradiated with the image light beam reflected by the region having a narrow phase pitch. The phase pitch of the reflective diffractive element can be set so as to irradiate the mirror region.

  The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image beam, a transmission mirror that reflects the image beam scanned by the scanning mirror, and the image beam reflected by the transmission mirror is projected onto the retina of the user's eyeball A projection mirror, wherein the surface of the projection mirror has a free-form surface, and the transmission mirror includes a transmissive diffraction element corresponding to a change in curvature of the free-form surface of the projection mirror.

  The said structure WHEREIN: The said transmission type diffraction element can be set as the structure which has phase distribution from which a phase pitch differs.

  In the above-described configuration, the free-form surface of the projection mirror has regions having different curvatures, and image light beams transmitted through a region having a wide phase pitch and a region having a narrow phase pitch of the transmission diffraction element have different curvatures of the projection mirror. The image light beam irradiated to each region and transmitted through the region having a large phase pitch is projected with a smaller curvature than the curvature of the projection mirror region irradiated with the image light beam transmitted through the region having a narrow phase pitch. The phase pitch of the transmission type diffractive element may be set so as to irradiate the mirror region.

  According to the present invention, the in-focus position can be set to an appropriate position.

FIG. 1 is a diagram of an image projection apparatus according to a comparative example and Example 1 as viewed from above. FIG. 2 is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the comparative example. FIG. 3A is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the first embodiment, and FIG. 3B is an enlarged view of the vicinity of the reflection mirror in FIG. 4A is a perspective view showing irregularities on the surface of the reflecting mirror in Example 1, and FIG. 4B is a diagram showing Z in the X direction of the reflecting mirror. FIG. 5 is a diagram illustrating contour lines in the reflecting mirror of the first embodiment. FIG. 6A is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the second embodiment, and FIG. 6B is an enlarged view of the vicinity of the reflective diffraction element in FIG. FIG. 7 is a diagram showing equiphase lines in the reflective diffraction element of Example 2. FIG. FIG. 8A is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the third embodiment, and FIG. 8B is an enlarged view of the vicinity of the transmissive diffraction element in FIG. FIG. 9 is a diagram showing equiphase lines in the transmission type diffractive element of Example 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram of an image projection apparatus according to a comparative example and Example 1 as viewed from above. The traveling direction of the light ray incident on the projection mirror 24 in the projection mirror 24 is defined as the X direction, and the direction orthogonal to the X direction in the projection mirror 24 is defined as the Y direction. In the following example, the X direction is the horizontal direction. As shown in FIG. 1, the image projection apparatus is a glasses type. The glasses have a temple 10 and a lens 20. A light source 12, a scanning mirror 14, and a reflection mirror 18 are provided on the temple 10 of the glasses. The light source 12 emits laser light 34 having a single wavelength or a plurality of wavelengths, for example. The scanning mirror 14 scans the laser beam 34 emitted from the light source 12 in a two-dimensional direction. The reflection mirror 18 reflects the scanned laser beam 34.

  Image data is input to the image input unit 15 from a camera and / or recording device. The control unit 16 controls the emission of the laser light 34 from the light source 12 based on the input image data. That is, the image signal is converted into laser light that is an image light beam by the light source 12 (light source unit). The control unit 16 is a processor such as a CPU (Central Processing Unit). For example, the controller 16 may be provided in an external device (for example, a portable terminal) without being provided in the glasses, or may be provided in the temple 10 of the glasses.

  The scanning mirror 14 scans the laser beam 34 emitted from the light source 12 two-dimensionally, and uses it as projection light for projecting an image on the retina 26 of the eyeball 22 of the user (user). The scanning mirror 14 is a MEMS (Micro Electro Mechanical Systems) mirror, for example, and scans the laser beam in two dimensions in the horizontal direction and the vertical direction. In the following example, the scanning direction of the laser beam is the X direction and the Y direction, but the laser beam may be scanned in a direction other than the X direction and the Y direction.

  The reflection mirror 18 reflects the laser beam 34 scanned by the scanning mirror 14 toward the lens 20. A projection mirror 24 is provided on the surface of the lens 20 on the user's eyeball 22 side. The projection mirror 24 projects an image on the retina 26 by irradiating the retina 26 of the eyeball 22 with the laser light 34 scanned by the scanning mirror 14 and reflected by the reflection mirror 18. That is, the user can recognize the image by the afterimage effect of the laser light projected on the retina 26. The projection mirror 24 is designed so that the focal position of the laser beam 34 scanned by the scanning mirror 14 is the pupil 28 of the eyeball 22. The laser beam 34 is incident on the projection mirror 24 from substantially the side (that is, substantially in the −X direction).

  FIG. 2 is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the comparative example. In FIG. 2, light beams L0 to L2 are light beams scanned in the horizontal direction by the scanning mirror 14, and are applied to the projection mirror 24 from the -X direction. The light beam L0 is a light beam corresponding to the center of the image, and the light beams L1 and L2 are light beams corresponding to the edge of the image. Light rays L0 to L2 are reflected by regions R0 to R2 of the projection mirror 24, respectively. The reflected light rays L 0 to L 2 are converged at the pupil 28 located at the center of the iris 29, pass through the crystalline lens 30, and reach the retina 26. The region R0 is a region that reflects the light ray L0 corresponding to the center of the image. The region R1 is a region in the −X direction (the direction in which the light rays L0 to L2 are incident) from the region R0. The region R2 is a region in the + X direction from the region R0. For Maxwellian viewing, the rays L0 to L2 intersect near the pupil 28. However, the focus positions F0 to F2 of the light beams L0 to L2 are shifted from the retina 26.

  In FIG. 2, the light ray L0 reflected by the projection mirror 24 enters the crystalline lens 30 as substantially parallel light and is focused near the retina 26. The light beam L1 reflected by the projection mirror 24 enters the crystalline lens 30 as diffused light. For this reason, the light beam L1 is focused farther than the retina 26. The light beam L2 reflected by the projection mirror 24 enters the crystalline lens 30 as convergent light. For this reason, the light ray L2 is focused closer to the retina 26. As described above, when the light ray L0 is focused in the vicinity of the retina 26, the focus position F1 is located farther from the projection mirror 24 than the retina 26. This is the distance D1 between the in-focus position F1 and the retina 26. The in-focus position F2 is closer to the projection mirror 24 than the retina 26. This is the distance D2 between the in-focus position F2 and the retina 26.

  Thus, the in-focus positions F0 to F2 are different when the light rays L0 to L2 incident on the projection mirror 24 from the −X direction are focused by the pupil 28, the curvature of the regions R0 to R2 of the projection mirror 24 is X This is because the directions differ and / or an optical path difference between the rays L0 to L2 occurs. For example, region R2 has a larger curvature than R1. That is, the region R2 has a higher light collection power than R1. For this reason, the focus position F2 is closer to the light source than F1. If the projection mirror 24 is arranged parallel to the face, the optical path of the light beam L2 becomes longer than that of the light beam L1. Thereby, the focus position F2 is further on the light source side than F1. As described above, in the comparative example, when the light rays L0 to L2 are converged in the vicinity of the pupil 28 for Maxwell's view, a region where the in-focus position greatly deviates from the retina 26 occurs in the image. Note that the optical system in the Y direction is substantially symmetric with respect to the X axis, and in the Y direction, the in-focus position does not easily shift as in the X direction.

  Example 1 is an example in which a reflection mirror 18 is used as an optical component. FIG. 3A is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the first embodiment, and FIG. 3B is an enlarged view of the vicinity of the reflection mirror in FIG. As shown in FIGS. 3A and 3B, the light rays L0 to L2 irradiated to the regions R0 to R2 of the projection mirror 24 are reflected in the regions S0 to S2 in the reflection mirror 18, respectively. The reflection mirror 18 has a free curved surface. Other configurations are the same as those of the first comparative example, and the description is omitted.

  4A is a perspective view showing irregularities on the surface of the reflecting mirror in Example 1, and FIG. 4B is a diagram showing the height Z of the reflecting mirror in the X direction. The X direction and the Y direction are directions corresponding to the X direction and the Y direction in the projection mirror 24. The height of the reflection mirror 18 is the Z direction. In FIG. 4A, the Z direction shows the surface irregularities of the reflection mirror 18 in an enlarged manner. As shown in FIGS. 4A and 4B, the surface of the reflection mirror 18 is substantially flat in the region S0, the surface of the reflection mirror 18 is concave in the region S1, and the surface of the reflection mirror 18 is in the region S2. Convex surface. Thereby, the condensing power is almost 0 in the region S0, the condensing power is positive in the region S1, and the condensing power is negative in the region S2. Therefore, the focus position F0 of the light beam L0 does not change from the comparative example. The focus position F1 of the light beam L1 is closer to the light source than in the comparative example of FIG. 2, and the focus position F2 of the light beam L2 is farther from the light source than in FIG. Thereby, the focus positions F0 to F2 are in the vicinity of the retina 26.

Let Z on the surface of the reflecting mirror 18 be a free-form surface expressed by the following equation.
Z = Σa _ij × X ⁱ × Y ^j
The origin (X = 0, Y = 0) corresponds to the center of the image, for example, near the region S0. a _ij is a coefficient. In order to vary the condensing power in the X direction, at least one of the coefficients a _ij of the odd-numbered terms is set to a finite value (other than 0). The condensing power in the Y direction in the projection mirror 24 is symmetric with respect to the X axis. Therefore, the coefficient a _ij of the term in which j is an odd number is set to 0. For example, the coefficients a ₃₀ and a ₁₂ are finite. Thereby, a free-form surface as shown in FIG. 4 can be realized. To further adjust the free-form surface of the reflecting mirror 18, the coefficients a ₁₀ and / or a ₂₀ may be a finite value. Furthermore, a high-order coefficient may be a finite value.

  In order to focus the laser beam 34 on the retina 26, the contour lines on the surface of the reflection mirror 18 were simulated. FIG. 5 is a diagram illustrating contour lines in the reflecting mirror of the first embodiment. In FIG. 5, Z at the center (X, Y) = (0, 0) is set to zero. The interval between the contour lines is 11.6 μm. Z decreases as going in the + X direction, and Z increases as going in the -X direction. FIG. 5 is a circle because the simulation is based on the retina. A part of the circle in FIG. 5 cut out as a rectangle corresponds to FIG.

  In the first embodiment, the surface of the reflection mirror 18 is set to a free curved surface such as a flat surface, a concave surface, or a convex surface in accordance with a change in the curvature of the free curved surface of the projection mirror 24. The region where the curvature of the projection mirror 24 is large is irradiated with the light beam reflected by the convex surface of the reflection mirror 18 having a high condensing power, and the region where the curvature of the projection mirror 24 is small is reflected by the concave surface of the reflection mirror 18 having a small condensing power. The irradiated light is irradiated. Thereby, as shown in FIG. 3, the light rays L <b> 0 to L <b> 2 can be focused near the retina 26. For example, the optical system including the projection mirror 24 is designed with the reflection mirror 18 as a plane without considering the focus positions F0 to F2 of the light beams L0 to L2. Thereafter, the surface of the reflection mirror 18 is designed as a free-form surface without changing the design of the projection mirror 24. Thereby, the focus positions F0 to F2 of the light beams L0 to L2 are adjusted. Since the condensing power that the reflection mirror 18 gives to each of the light beams L0 to L2 is weak, the focus positions F0 to F2 can be adjusted with little influence on the locus of the light beams L0 to L2. Therefore, an optical system can be designed easily.

  FIG. 6A is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the second embodiment, and FIG. 6B is an enlarged view of the vicinity of the reflective diffraction element in FIG. As shown in FIGS. 6A and 6B, a reflective diffraction element 18a is used as an optical component. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  In order to focus the laser beam 34 on the retina 26, the phase distribution in the diffraction element 18a was simulated. FIG. 7 is a diagram showing equiphase lines in the reflective diffraction element of Example 2. FIG. In FIG. 7, the interval between the lines is 50 × 2π rad. The interval between the equiphase lines corresponds to the pitch of the diffraction elements 18a. As in the second embodiment, even when the reflective diffraction element 18a is used, the condensing power in the region S0 is almost 0, the condensing power in the region S1 is positive, and the condensing power in the region S2 is negative. it can.

  FIG. 8A is a diagram illustrating an optical path of a light beam in the image projection apparatus according to the third embodiment, and FIG. 8B is an enlarged view of the vicinity of the transmissive diffraction element in FIG. As shown in FIGS. 8A and 8B, a transmissive diffraction element 18b is used as an optical component. Light rays L0 to L2 reflected by the scanning mirror 14 pass through the regions S0 to S2 of the diffraction element 18b, respectively. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  In order to focus the laser beam 34 on the retina 26, the phase distribution in the diffraction element 18b was simulated. FIG. 9 is a diagram showing equiphase lines in the transmission type diffractive element of Example 3. FIG. In FIG. 9, the interval between the lines is 7.5 × 2π rad. As in the third embodiment, even when the transmissive diffraction element 18b is used, the light collecting power in the region S0 is almost 0, the light collecting power in the region S1 is positive, and the light collecting power in the region S2 is negative. it can.

  As shown in FIG. 2, in Comparative Example 1, the projection mirror 24 (first mirror) is arranged in front of the user's eyeball 22. The projection mirror 24 projects an image on the retina 26 by reflecting a light ray incident from the −X direction and irradiating the retina 26 of the eyeball 22. In such an arrangement, as described with reference to FIG. 2, it is difficult to set the focusing positions F0 to F2 of the light beams L0 to L2 near the retina 26.

  Therefore, according to the first to third embodiments, as shown in FIGS. 3, 6, and 8, optical components (reflection mirror 18, reflection type diffraction element) that reflect or transmit the light beam scanned by the scanning mirror 14 (scanning unit). 18a or transmissive diffractive element 18b). The projection mirror 24 irradiates light rays L0 to L2 reflected or transmitted by the optical component. In this way, the optical components are arranged.

  The optical component reflects the light condensing power in the region S1 (third region) that reflects or passes the light beam L1 irradiated to the region R1 (first region) among the light beams scanned by the scanning mirror 14 into the region R2 (second region). Is set to be larger than the condensing power in the region S2 (fourth region) in which the light beam L2 (second light beam) applied to the light beam is reflected or passed.

  Thereby, the focus position F1 of the light beam L1 approaches the projection mirror 24, and the focus position F2 of the light beam L2 moves away from the projection mirror 24. Therefore, the focus positions F0 to F2 of the light beams L0 to L2 can be set near the retina 26. Therefore, the focus positions F0 to F2 can be set to appropriate positions.

  Further, a distance D1 (first distance) between the position F1 (first position) where the light beam L1 is focused and the retina 26, and a distance D2 (position 2) between the position F2 (second position) where the light beam L2 is focused and the retina 26 ( The second distance) is smaller than the distance D1 and the distance D2 when the condensing power in the region S1 and the region S2 is assumed to be the same. Thereby, the focus positions F0 to F2 of the light beams L0 to L2 can be set near the retina 26.

  As a method for setting the condensing power in the regions S1 and S2, the optical component is a reflecting mirror 18 (second mirror) as in the first embodiment. The curvature of the reflection mirror 18 in the region S1 is made larger than the curvature of the reflection mirror 18 in the region S2. Thereby, the condensing power in area | region S1 can be made larger than the condensing power in area | region S2. Note that the curvature is positive for the concave surface as in the region S1 in FIGS. 4A and 4B and negative for the convex surface as in the region S2. Further, by using the reflection mirror 18 as an optical component, even when the light beams L0 to L2 include a plurality of wavelengths, the condensing power of the light beams L0 to L2 of each wavelength can be set with a single curved surface.

  That is, according to the first embodiment, as shown in FIGS. 3A to 5, the free curved surface of the reflection mirror 18 includes a concave curved surface and a convex curved surface, and the free curved surface of the projection mirror 24 has regions having different curvatures. doing. The image light beams reflected by the concave curved surface and the convex curved surface of the reflecting mirror 18 are respectively irradiated on different areas of the projection mirror 24. The image light beam reflected by the concave curved surface (region S1) enters the region R1 of the projection mirror 24 having a smaller curvature than the curvature of the region R2 of the projection mirror 24 irradiated with the image light beam reflected by the convex curved surface (region S2). A concave curved surface and a convex curved surface of the reflecting mirror 18 are set so as to be irradiated. Thereby, the focusing positions F0 to F2 can be set to appropriate positions.

  As in the second and third embodiments, the optical component may be diffractive elements 18a and 18b. The pitch of the diffraction elements 18a and 18b in the region S1 is set larger than the pitch of the diffraction elements 18a and 18b in the region S2. Thereby, the condensing power in area | region S1 can be made larger than the condensing power in area | region S2. By using the diffractive elements 18a and 18b as optical components, the light condensing power can be set more accurately. The condensing power of the diffractive elements 18a and 18b is wavelength dependent. For this reason, it is preferable that the light beams L0 to L2 have a single wavelength. When the light beams L0 to L2 include light having a plurality of wavelengths, it is preferable to stack diffraction elements corresponding to the respective wavelengths.

  That is, according to the second embodiment, as shown in FIGS. 6A to 7, the reflection mirror includes the reflection type diffraction element 18 a corresponding to the curvature change of the free curved surface of the projection mirror 24. The reflective diffraction element 18a has a phase distribution with different phase pitches. The image light beams reflected by the region S2 having a large phase pitch and the region S1 having a small phase pitch of the reflective diffraction element 18a are respectively irradiated on the regions R2 and R1 having different curvatures of the projection mirror 24. The phase pitch of the reflective diffraction element 18a is set so that the image light beam reflected by the region S2 is irradiated to the region R2 having a smaller curvature than the curvature of the region R1 irradiated with the image light beam reflected by the region S1. Has been. Thereby, the focusing positions F0 to F2 can be set to appropriate positions.

  Further, according to the third embodiment, as shown in FIGS. 8A to 9, the transmission mirror includes the transmission type diffraction element 18 b corresponding to the curvature change of the free curved surface of the projection mirror 24. The transmissive diffraction element 18b has phase distributions with different phase pitches. The image rays transmitted through the wide phase pitch region S2 and the narrow phase pitch region S1 of the transmissive diffraction element 18b are irradiated to the regions R2 and R1 having different curvatures of the projection mirror 24, respectively. The image light beam transmitted through the region S2 is irradiated to the region R2 having a smaller curvature than the curvature of the region R1 of the projection mirror 24 to which the image light beam transmitted through the region S1 is irradiated. The phase pitch is set. Thereby, the focusing positions F0 to F2 can be set to appropriate positions.

  Although the example in which the curvature of the projection mirror 24 is different in the X direction has been described, the projection mirror 24 may be a diffraction element. In order to allow the light beams L0 to L2 to pass through the pupil 28, the condensing power of the projection mirror 24 in the region R1 is preferably smaller than the condensing power of the projection mirror 24 in the region R2. Although the example in which the projection mirror 24 is a half mirror provided in the lens 20 has been described, the projection mirror 24 may be a total reflection mirror.

  The region R1 and the region R2 are located on both sides in the incident direction of the light rays L0 to L2 with respect to the position (region R0) corresponding to the center of the image in the projection mirror 24. Thus, when the regions R0 to R2 are located, in Comparative Example 1, the deviation from the retina 26 from the in-focus positions F0 to F2 becomes large. Therefore, it is preferable to vary the condensing powers of the regions S0 to S2.

  Further, the distance between the region R1 and the region R2 in the projection mirror 24 is larger than the distance between the region S1 and the region S2 in the optical component. In such an optical system having a large distance between the regions R1 and R2, if the light rays L0 to L2 are converged in the vicinity of the pupil 28, the condensing powers of the regions R1 and R2 are greatly different. Further, the optical paths of the light beams L0 to L2 are greatly different. As a result, the focus positions F1 and F2 are greatly displaced from the retina 26 as shown in FIG. Therefore, in such an optical system, it is preferable to use optical components having different condensing powers in the regions S1 and S2.

  The optical system of the light beams L0 to L2 is substantially symmetric with respect to the Y-axis direction. Therefore, the condensing power at the pair of positions in the optical component corresponding to the pair of positions in the projection mirror 24 that is symmetric with respect to the line extending in the X direction through the position corresponding to the center of the image in the projection mirror 24 is substantially Are preferably equal. For example, in FIG. 5, the curvature at the position symmetrical to the straight line (X axis) of Y = 0 is the same. 7 and 9, the pitch of the diffraction elements symmetrical to the straight line of Y = 0 is the same.

  Although the eyeglass-type HMD has been described as an example of the image projection apparatus, an image projection apparatus other than the HMD may be used. Although an example in which an image is projected onto the retina 26 of one eyeball 22 has been shown, an image may be projected onto the retina 26 of both eyeballs 22. Although the scanning mirror 14 has been described as an example of the scanning unit, the scanning unit only needs to be able to scan light rays. For example, other parts such as an electro-optic material potassium tantalate niobate (KTN) crystal may be used as the scanning unit. Although laser light has been described as an example of the light beam, light other than laser light may be used. The condensing power in the regions S1 and S2 of the optical component may be either positive or negative. Although the direction in which the light beams L0 to L2 are incident on the projection mirror 24 has been described by taking the horizontal direction as an example, the light beams L0 to L2 may be incident from a vertical direction or an oblique direction.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 crane 12 light source 14 scanning mirror 16 control part 18 reflection mirror 18a, 18b diffraction element 20 lens 22 eyeball 24 projection mirror 26 retina 28 pupil 29 iris 30 crystalline lens 34 laser light

The present invention includes a scanning unit that scans a light beam emitted from a light source in a two-dimensional direction, an optical component that reflects or transmits the light beam scanned by the scanning unit, and an optical component that is disposed in front of a user's eyeball. A first mirror for projecting an image on the retina by reflecting the reflected or transmitted light beam and irradiating the retina of the eyeball, and the first mirror has a first region and a second region. In the first mirror, the first region is positioned in a direction in which the light beam is incident from the second region, and the optical component irradiates the first region of the light beam scanned by the scanning unit. The condensing power in the third region that reflects or passes one light beam is greater than the condensing power in the fourth region that reflects or passes the second light beam irradiated to the second region among the light beams scanned by the scanning unit. big That it is set to an image projection apparatus according to claim.

In the above configuration, the optical component may be a Ah Ru configuration in the diffraction grating.

The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image light beam, a reflection mirror that reflects the image light beam scanned by the scanning mirror, and the image light beam reflected by the reflection mirror is projected onto the retina of the user's eyeball comprising a projection mirror, the said surface of the projection mirror has a free curved surface having a region of different curvature, the surface of the reflecting mirror have a free curved surface which includes a concave surface and a convex surface, in the projection mirror The region where the image light beam reflected by the concave curved surface is reflected is an image projection device located on the incident side of the image light beam from the region where the image light beam reflected by the convex curved surface is reflected .

The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image light beam, a reflection mirror that reflects the image light beam scanned by the scanning mirror, and the image light beam reflected by the reflection mirror is projected onto the retina of the user's eyeball A projection mirror, wherein the surface of the projection mirror has a free curved surface having regions with different curvatures, and the surface of the reflection mirror has a free curved surface including a concave curved surface and a convex curved surface, The concave curved surface of the reflection mirror is irradiated so that the reflected image light beam is irradiated on the region of the projection mirror having a smaller curvature than the curvature of the region of the projection mirror irradiated with the image light beam reflected on the convex curved surface. as well as Curved is an image projection apparatus is set.

The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image light beam, a reflection mirror that reflects the image light beam scanned by the scanning mirror, and the image light beam reflected by the reflection mirror is projected onto the retina of the user's eyeball comprising a projection mirror, and has a free-form surface surface of the projection mirror having regions with different curvatures, wherein the reflecting mirror is viewed including the reflection type diffraction element having different phase distributions in phase pitch, in the projection mirror The region where the image light beam reflected by the region having a phase distribution with a large condensing power in the reflection type diffraction element is reflected is a phase distribution with a small condensing power in the reflection type diffraction element. Image rays reflected by the region with is an image projection device located on the incident side of the image light from the area to be reflected.

The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image light beam, a reflection mirror that reflects the image light beam scanned by the scanning mirror, and the image light beam reflected by the reflection mirror is projected onto the retina of the user's eyeball A projection mirror, the surface of the projection mirror has a free-form surface having regions with different curvatures, and the reflection mirror includes a reflection type diffraction element having a phase distribution with a different phase pitch, and the reflection type diffraction element image rays reflected by the region having a large phase distribution of the light collecting power in the image light reflected by the region with a small phase distribution of light collecting power in a reflective diffractive element Wherein As is irradiated onto the region of small the projection mirror curvature than the curvature of the region of the projection mirrors Isa, an image projection apparatus in which the phase pitch of the reflection type diffraction element is set.

The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image beam, an optical component that transmits the image beam scanned by the scanning mirror, and a projection that projects the image beam transmitted through the optical component onto the retina of the user's eyeball and the mirror, provided, having a free-form surface surface of the projection mirror having regions with different curvatures, wherein the optical component is observed including a transmission type diffraction element having different phase distributions in phase pitch, in the projection mirror, the The region where the image light beam transmitted through the region of the transmission type diffractive element having the high light collection power is reflected reflects the image light beam transmitted through the region of the transmission type diffractive element having the low light collection power. An image projection device located on the incident side of the image rays from frequency.

The present invention generates a light source unit that emits a light beam, an image input unit that inputs image data, and an image light beam based on the input image data, and performs emission control of the image light beam from the light source unit. A control unit that performs scanning, a scanning mirror that scans the image beam, an optical component that transmits the image beam scanned by the scanning mirror, and a projection that projects the image beam transmitted through the optical component onto the retina of the user's eyeball The projection mirror surface has a free-form surface having regions with different curvatures, and the optical component includes a transmissive diffractive element having a phase distribution with a different phase pitch, and in the transmissive diffractive element, large phase distribution image light transmitted through the region with the converging power, the image light transmitted are irradiated areas with small phase distribution of light collecting power in the transmission type diffraction element Serial so as to irradiate a region of small the projection mirror curvature than the curvature of the region of the projection mirror, an image projection apparatus in which the phase pitch of the transmission diffraction element is set.

In the first embodiment, the surface of the reflection mirror 18 is set to a free curved surface such as a flat surface, a concave surface, or a convex surface in accordance with a change in the curvature of the free curved surface of the projection mirror 24. Projection in the area of curvature is large mirror 24 to irradiate a light beam reflected by the convex surface of the small reflection mirror 18 of converging optical power, in the area of curvature of the projection mirror 24 is less reflected by the large concave reflecting mirror 18 of the light condensing power The irradiated light is irradiated. Thereby, as shown in FIG. 3, the light rays L <b> 0 to L <b> 2 can be focused near the retina 26. For example, the optical system including the projection mirror 24 is designed with the reflection mirror 18 as a plane without considering the focus positions F0 to F2 of the light beams L0 to L2. Thereafter, the surface of the reflection mirror 18 is designed as a free-form surface without changing the design of the projection mirror 24. Thereby, the focus positions F0 to F2 of the light beams L0 to L2 are adjusted. Since the condensing power that the reflection mirror 18 gives to each of the light beams L0 to L2 is weak, the focus positions F0 to F2 can be adjusted with little influence on the locus of the light beams L0 to L2. Therefore, an optical system can be designed easily.

Claims (17)

A scanning unit that scans light emitted from the light source in a two-dimensional direction;
An optical component that reflects or transmits the light beam scanned by the scanning unit;
A first mirror that is disposed in front of a user's eyeball, reflects a light beam reflected or transmitted by the optical component and irradiates the retina of the eyeball, thereby projecting an image on the retina;
Comprising
The first mirror has a first region and a second region, and in the first mirror, the first region is located in a direction in which the light beam enters from the second region,
The optical component has a condensing power in a third region that reflects or passes a first light beam that irradiates the first region out of the light beam scanned by the scanning unit, and the optical component of the light beam scanned by the scanning unit. An image projection apparatus characterized in that it is larger than the condensing power in the fourth region that reflects or passes the second light beam applied to the second region. The first distance between the first position where the first light beam is focused and the retina, and the second distance between the second position where the second light beam is focused and the retina are:
2. The image projection apparatus according to claim 1, wherein each of the third regions and the fourth region is smaller than the first distance and the second distance when the condensing power is assumed to be the same. The optical component is a second mirror;
3. The image projector according to claim 1, wherein a curvature of the second mirror in the third region is larger than a curvature of the second mirror in the fourth region. The optical component is a diffraction grating;
The image projection apparatus according to claim 1, wherein a pitch of the diffraction grating in the third region is larger than a pitch of the diffraction grating in the fourth region.   5. The image projection apparatus according to claim 1, wherein the light condensing power of the first mirror in the first region is smaller than the light condensing power of the first mirror in the second region. 6.   The first region and the second region are located on both sides in a direction in which the light ray enters with respect to a position corresponding to a center of the image in the first mirror. The image projection device according to claim 5.   The distance between the first region and the second region in the first mirror is larger than the distance between the third region and the fourth region in the optical component. The image projection device according to one item.   A pair in the optical component corresponding to a pair of positions in the first mirror that is symmetrical with respect to a line extending in the direction in which the light ray passes through a position corresponding to the center of the image in the first mirror. The image projection apparatus according to claim 1, wherein the condensing powers at the positions are substantially equal. A light source that emits light rays;
An image input unit for inputting image data;
A control unit that generates an image light beam based on the input image data and performs emission control of the image light beam from the light source unit;
A scanning mirror for scanning the image beam;
A reflection mirror that reflects the image light beam scanned by the scanning mirror;
A projection mirror that projects the image light beam reflected by the reflection mirror onto the retina of the user's eyeball;
Comprising
An image projection apparatus wherein the surface of the projection mirror has a free-form surface, and the surface of the reflection mirror has a free-form surface corresponding to a change in curvature of the free-form surface of the projection mirror.   The image projection apparatus according to claim 9, wherein the free curved surface of the reflecting mirror includes a concave curved surface and a convex curved surface. The free-form surface of the projection mirror has regions with different curvatures,
Image rays reflected by the concave curved surface and the convex curved surface of the reflecting mirror are respectively irradiated to different areas of the projection mirror,
The reflection is performed so that the image light beam reflected by the concave curved surface is irradiated to the region of the projection mirror having a smaller curvature than the curvature of the region of the projection mirror irradiated with the image light beam reflected by the convex curved surface. The image projection apparatus according to claim 10, wherein a concave curved surface and a convex curved surface of the mirror are set. A light source that emits light rays;
An image input unit for inputting image data;
A control unit that generates an image light beam based on the input image data and performs emission control of the image light beam from the light source unit;
A scanning mirror for scanning the image beam;
A reflection mirror that reflects the image light beam scanned by the scanning mirror;
A projection mirror that projects the image light beam reflected by the reflection mirror onto the retina of the user's eyeball;
Comprising
The image projection apparatus includes: a projection mirror having a free-form surface; and the reflection mirror includes a reflective diffraction element corresponding to a change in curvature of the free-form surface of the projection mirror.   The image projection apparatus according to claim 12, wherein the reflective diffraction element has phase distributions having different phase pitches. The free-form surface of the projection mirror has regions with different curvatures,
The image light beams reflected by the region having a wide phase pitch and the region having a narrow phase pitch of the reflective diffractive element are respectively irradiated on regions having different curvatures of the projection mirror,
The image light beam reflected by the wide phase pitch region is irradiated to the projection mirror region having a smaller curvature than the projection mirror region irradiated with the image light beam reflected by the narrow phase pitch region. The image projection apparatus according to claim 13, wherein a phase pitch of the reflective diffraction element is set. A light source that emits light rays;
An image input unit for inputting image data;
A control unit that generates an image light beam based on the input image data and performs emission control of the image light beam from the light source unit;
A scanning mirror for scanning the image beam;
A transmission mirror that reflects the image light beam scanned by the scanning mirror;
A projection mirror that projects the image light beam reflected by the transmission mirror onto the retina of the user's eyeball;
Comprising
An image projection apparatus, wherein the surface of the projection mirror has a free-form surface, and the transmission mirror includes a transmission type diffraction element corresponding to a change in curvature of the free-form surface of the projection mirror.   The image projection apparatus according to claim 15, wherein the transmissive diffraction elements have phase distributions having different phase pitches. The free-form surface of the projection mirror has regions with different curvatures,
The image light beams transmitted through the wide phase pitch region and the narrow phase pitch region of the transmissive diffraction element are respectively irradiated to different regions of the curvature of the projection mirror,
The image light beam transmitted through the region having a large phase pitch is irradiated to the region of the projection mirror having a smaller curvature than the curvature of the region of the projection mirror irradiated with the image light beam transmitted through the region having a narrow phase pitch. The image projection apparatus according to claim 16, wherein a phase pitch of the transmissive diffraction element is set.

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