Projection substrate and eyeglasses-type terminal

Abstract

This projection substrate comprises: a substrate; an incidence diffraction grating onto which projection light for projecting image light is incident and which guides at least portion of the incidence projection light toward a predetermined direction in the substrate; an emission diffraction grating onto which the projection light guided by the incidence diffraction grating is incident and which emits at least portion of the incident projection light as image light; a filling material which is filled in groove parts of the incidence diffraction grating and the emission diffraction grating and has a refractive index smaller than the incidence diffraction grating and the emission diffraction grating; a protective film for covering and protecting the surface of the filling material; and an optical lens provided on a surface of the protective film on the side opposite to the substrate.

Description

Projection board and eyeglasses-type terminal

[0001] The present invention relates to a projection board and an eyeglass-type terminal.

[0002] Conventionally, there are known eyeglass-type devices, head-mounted displays, and the like that display two-dimensional images for a user to observe using an optical system including a waveguide or the like (see, for example, Patent Documents 1 and 2). Also, there is known a two-dimensional diffraction grating that diffracts light in two directions (see, for example, Patent Document 3).

[0003] Japanese Patent Application Publication No. 2017-207686 International Publication No. 2023 / 047488 U.S. Patent No. 8,160,411

[0004] Such eyeglass-type devices used a projection substrate with a diffraction grating formed on the substrate. Conventional projection substrates diffract incident light using the difference in refractive index between the material forming the diffraction grating and air, so the diffraction grating was formed so that it was in contact with an air layer. However, diffraction gratings in contact with an air layer were vulnerable to impacts, and the substrate itself could easily become distorted.

[0005] The present invention has been made in consideration of these points, and aims to improve the impact resistance of a substrate on which a diffraction grating is formed, thereby making it easier to handle the substrate.

[0006] In a first aspect of the present invention, there is provided a projection substrate for projecting image light, comprising: a substrate; an incident diffraction grating provided on the substrate, onto which projection light for projecting the image light is incident and which guides at least a portion of the incident projection light in a predetermined direction within the substrate; an exit diffraction grating provided on the substrate, onto which the projection light guided by the incident diffraction grating is incident and which emits at least a portion of the incident projection light as the image light; a filling material which is filled in grooves of the incident diffraction grating and the exit diffraction grating and has a refractive index smaller than that of the incident diffraction grating and the exit diffraction grating; a protective film which covers and protects the surface of the filling material; and an optical lens provided on the surface of the protective film opposite the substrate.

[0007] The filling material may include mesoporous silica having a porous structure. The device may further include an adhesive sheet provided between the protective film and the filling material, and bonding the protective film to the filling material.

[0008] The filler material may be provided on a first surface of the substrate and on a second surface of the substrate opposite the first surface.

[0009] The protective film may have a first protective film covering the surface of the filling material formed on the first surface of the substrate, and a second protective film covering the surface of the filling material formed on the second surface of the substrate, and the optical lens may have a first optical lens provided on the surface of the first protective film opposite the substrate, and a second optical lens provided on the surface of the second protective film opposite the substrate.

[0010] When the diopter of the image indicated by the image light emitted by the output diffraction grating is D", the diopter of the eye of the user observing the image light emitted by the output diffraction grating is D, and the distance between the first optical lens and the second optical lens is d, the diopter D1 of the first optical lens and the diopter D2 of the second optical lens may satisfy the following formulas: D1=(D+D") / (1+d·D"), D2=-D".

[0011] In a predetermined width direction parallel to the first surface of the substrate, the lengths of the substrate and the protective film may be formed to be a predetermined first distance, and the length of the optical lens may be formed to be a length different from the first distance.

[0012] In a second aspect of the present invention, there is provided an eyeglass-type terminal worn by a user, the eyeglass-type terminal comprising: the projection substrate of the first aspect, which is provided as at least one of a lens for the user's right eye and a lens for the user's left eye and projects the image light in the direction of the user's eye; a frame that fixes the projection substrate; and a projection unit that is provided on the frame and irradiates the projection light onto the incident diffraction grating of the projection substrate.

[0013] The projection substrate may be formed so that the lengths of the substrate and the protective film are a predetermined first distance in a predetermined width direction parallel to a first surface of the substrate, and the length of the optical lens is formed to a length different from the first distance, and the frame may have a first fixing hole for fixing the projection substrate, the first fixing hole having a length corresponding to the first distance in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the projection substrate in a direction perpendicular to the first surface of the substrate, and a second fixing hole for fixing the optical lens, the second fixing hole being formed adjacent to the first fixing hole on the side of at least one of the first surface and a second surface opposite to the first surface of the substrate, the second fixing hole having a length corresponding to the length of the optical lens in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the optical lens in a direction perpendicular to the first surface of the substrate.

[0014] In the projection substrate, the filling material is provided on a first surface of the substrate and a second surface of the substrate opposite to the first surface, the protective film has a first protective film covering a surface of the filling material formed on the first surface of the substrate and a second protective film covering a surface of the filling material formed on the second surface of the substrate, the optical lens has a first optical lens provided on a surface of the first protective film opposite to the substrate and a second optical lens provided on a surface of the second protective film opposite to the substrate, and is formed so that lengths of the substrate, the first protective film, and the second protective film are a predetermined first distance in a predetermined width direction parallel to the first surface of the substrate, a length of the first optical lens is a second distance different from the first distance, and a length of the second optical lens is a third distance different from the first distance, and the frame is a first fixing hole for fixing the projection substrate, the first fixing hole having a length corresponding to the first distance and a depth corresponding to a thickness of the projection substrate in a direction perpendicular to the first surface of the substrate; a second fixing hole for fixing the first optical lens, the second fixing hole being formed adjacent to the first fixing hole on the side of the first surface of the substrate, the second fixing hole having a length corresponding to a length of the first optical lens in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the first optical lens in the direction perpendicular to the first surface of the substrate; and a third fixing hole for fixing the second optical lens, the third fixing hole being formed adjacent to the first fixing hole on the side of the second surface of the substrate, the second fixing hole having a length corresponding to the length of the second optical lens in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the second optical lens in the direction perpendicular to the first surface of the substrate.

[0015] According to the present invention, the impact resistance of the substrate on which the diffraction grating is formed is improved, and the substrate can be easily handled.

[0016] 1 shows an example of the configuration of the eyeglasses-type terminal 10 according to the present embodiment. 2 shows an outline of the optical path of the projection light in the eyeglasses-type terminal 10 according to the present embodiment. 3 shows an outline of the optical path of the projection light in the projection substrate 100 according to the present embodiment. 4 shows an example of the projection light L irradiated onto the projection substrate 100 by the projection unit 120 according to the present embodiment and the image light P emitted from the projection substrate 100. 5 shows an example of the configuration of the projection substrate 100 according to the present embodiment. 6 shows a first modified example of the projection substrate 100 according to the present embodiment. 7 shows an example of the cross-sectional configuration of the projection substrate 100 according to the present embodiment. 8 shows a second modified example of the projection substrate 100 according to the present embodiment. 9 shows an example of the manufacturing flow of the projection substrate 100 according to the present embodiment. 10 shows an example of the configuration of the process of forming the projection substrate 100 according to the present embodiment. 11 shows a third modified example of the projection substrate 100 according to the present embodiment. 12 shows a fourth modified example of the projection substrate 100 according to the present embodiment. 13 shows a first modified example of the lens unit L according to the present embodiment. 14 shows a second modified example of the lens unit L according to the present embodiment. 15 shows a schematic configuration of the process of assembling the eyeglasses-type terminal 10 according to the present embodiment. 16 shows a third modified example of the lens unit L according to the present embodiment. 17 shows an example of the configuration of the lens unit L having an air gap according to the present embodiment.

[0017] <Configuration example of eyeglasses-type terminal 10> Fig. 1 shows a configuration example of an eyeglasses-type terminal 10 according to this embodiment. In this embodiment, three mutually orthogonal axes are defined as an X-axis, a Y-axis, and a Z-axis. The eyeglasses-type terminal 10 is, for example, a wearable device worn by a user. The eyeglasses-type terminal 10 projects image light onto a display area provided on a projection substrate 100 while allowing the user to observe a scene through the glasses. The eyeglasses-type terminal 10 includes the projection substrate 100, a frame 110, and a projection unit 120.

[0018] The projection substrate 100 projects the incident projection light onto the display surface as image light. For example, the projection substrate 100 transmits at least a portion of the light incident from the first surface toward the user's eye in the direction of the second surface. Furthermore, the projection substrate 100 projects the light incident from the second surface as image light onto the user's eye via a diffraction grating provided on the projection substrate 100.

[0019] Here, the first surface of the projection substrate 100 is the surface that faces away from the user when the user wears the eyeglasses-type terminal 10. The second surface of the projection substrate 100 is the surface that faces the user's eyes when the user wears the eyeglasses-type terminal 10. FIG. 1 shows an example in which the first and second surfaces of the projection substrate 100 are arranged approximately parallel to the XY plane. The projection substrate 100 is, for example, a glass substrate on which a diffraction grating that functions as a waveguide is formed. The projection substrate 100 will be described later.

[0020] The frame 110 fixes the projection substrate 100. The frame 110 is provided with the projection substrate 100 as at least one of a lens for the user's right eye and a lens for the left eye. Fig. 1 shows an example in which the frame 110 is provided with a projection substrate 100a as a lens for the user's right eye and a projection substrate 100b as a lens for the left eye.

[0021] Alternatively, the frame 110 may be provided with one projection board 100 as a lens for the user's right eye or left eye. The frame 110 may also be provided with one projection board 100 as lenses for both eyes of the user. In this case, the frame 110 may have a goggle shape. The frame 110 has temples, a strap, and other parts that allow the user to wear the eyeglass-type terminal 10.

[0022] The projection unit 120 is provided on the frame 110 and irradiates projection light toward the projection substrate 100 to project image light onto the projection substrate 100. One or more such projection units 120 are provided on the frame 110. Fig. 1 shows an example in which a projection unit 120a for irradiating projection light L1 onto the projection substrate 100a and a projection unit 120b for irradiating projection light L2 onto the projection substrate 100b are provided on the frame 110.

[0023] The projection unit 120 may be provided at a portion of the frame 110 where the projection substrate 100 is fixed, or may be provided at a temple or the like of the frame 110. It is desirable that the projection unit 120 be provided so as to be integrated with the frame 110. For example, the projection unit 120 irradiates the projection substrate 100 with projection light including one wavelength, allowing the user to observe a monochromatic image. Alternatively, the projection unit 120 may irradiate the projection substrate 100 with projection light including multiple wavelengths, allowing the user to observe an image including multiple colors.

[0024] 2 shows an outline of the optical path of projection light in the eyeglass-type terminal 10 according to this embodiment. The projection unit 120 irradiates the projection light onto an incident area 210 provided on the projection substrate 100. The incident area 210 guides the projection light within the substrate of the projection substrate 100. The projection substrate 100 then emits the projection light guided within the substrate from an emission area 230 as image light. The incident area 210 and the emission area 230 will be described later.

[0025] 3 shows an outline of the optical path of projection light on the projection substrate 100 according to this embodiment. The projection substrate 100 has an incident region 210, a branching region 220, and an exit region 230. Projection light L enters the incident region 210, passes through the branching region 220, and exits from the exit region 230 as image light P. The branching region 220 guides the projection light L part by part to the exit region 230 as the projection light L travels away from the incident region 210.

[0026] Similarly, as the projection light L travels away from the branching region 220, the emission region 230 also emits a portion of the projection light L as part of the image light P. In this way, the projection board 100 emits the projection light L that has entered the entrance region 210 from the emission region 230 as image light P.

[0027] <Examples of Projection Light L and Image Light P> FIG. 4 shows an example of the projection light L irradiated onto the projection substrate 100 by the projection unit 120 according to this embodiment and the image light P emitted from the projection substrate 100. The projection unit 120 irradiates the projection light L, for example, toward the second surface of the projection substrate 100 located in the +Z direction. The projection light L corresponds to an image to be shown to the user. For example, when the projection light L is projected onto a screen or the like placed on a surface substantially parallel to the XY plane, an image M1 is displayed on the screen for the user to observe. The image to be shown to the user is, for example, an augmented reality (AR) image or a virtual reality (VR) image created by a processor included in the projection unit 120. In this way, the projection unit 120 irradiates, as the projection light L, a plurality of light rays that form an image M1 on a surface substantially parallel to the XY plane.

[0028] In this embodiment, an example will be described in which the projection unit 120 projects a substantially rectangular image M1 with the X-axis direction as the longitudinal direction on a plane substantially parallel to the XY plane. Also, in Fig. 4, five of the multiple light rays emitted by the projection unit 120 are shown as input light rays 20. For example, the light ray corresponding to the upper left pixel of the image is the first input light ray 20a, the light ray corresponding to the lower left pixel of the image is the second input light ray 20b, the light ray corresponding to the central pixel of the image is the third input light ray 20c, the light ray corresponding to the upper right pixel of the image is the fourth input light ray 20d, and the light ray corresponding to the lower right pixel of the image is the fifth input light ray 20e.

[0029] The projection unit 120, for example, irradiates the projection light L onto the entrance region 210 of the projection substrate 100 so as to create an erect virtual image at infinity or at a predetermined position. The projection light incident on the entrance region 210 passes through the branching region 220 and is emitted from the exit region 230 as image light P. The image light P is emitted from the exit region 230 and enters the user's eye, which is a distance d away from the projection substrate 100. The image light P is then focused as image M2 on the retina of the user's eye. In this way, the image light P includes a plurality of light beams that are focused as image M2.

[0030] 4, five of the multiple ray bundles that are emitted from the circular region C of the emission region 230 of the projection substrate 100 and form an image at a predetermined position are shown as output ray bundles 30. For example, the ray bundle that forms an image as the lower right pixel of the image is designated as the first output ray bundle 30a, the ray bundle that forms an image as the upper right pixel of the image is designated as the second output ray bundle 30b, the ray bundle that forms an image as the central pixel of the image is designated as the third output ray bundle 30c, the ray bundle that forms an image as the lower left pixel of the image is designated as the fourth output ray bundle 30d, and the ray bundle that forms an image as the upper left pixel of the image is designated as the fifth output ray bundle 30e.

[0031] Each ray bundle corresponds to one of the multiple input light rays 20 incident from the projection unit 120. For example, the first output ray bundle 30a corresponds to the first input light ray 20a, and includes multiple light rays generated by multiple branching and multiple diffractions of the first input light ray 20a as it travels from the incident region 210 to the exit region 230 of the projection substrate 100. Similarly, the second output ray bundle 30b corresponds to the second input light ray 20b, the third output ray bundle 30c corresponds to the third input light ray 20c, the fourth output ray bundle 30d corresponds to the fourth input light ray 20d, and the fifth output ray bundle 30e corresponds to the fifth input light ray 20e.

[0032] In other words, the image M2 formed on the retina of the user's eye by the image light P emitted from the emission region 230 corresponds to the image M1 projected by the projection light L emitted by the projection unit 120. This allows the user wearing the eyeglass-type terminal 10 to feel as if the image M2 is being projected onto the second surface of the projection substrate 100, superimposed on the scenery seen through the projection substrate 100. In other words, the emission region 230 functions as a display region that displays the image M2 corresponding to the image M1 projected by the projection light L.

[0033] 4, an example is shown in which the image M2 observed by the user is an image obtained by vertically and horizontally inverting the image M1 projected by the projection light L. Note that the image M1 projected by the projection light L may be a still image, or alternatively, may be a moving image. Next, a more specific example of the projection substrate 100 will be described.

[0034] <Configuration Example of Projection Substrate 100> Fig. 5 shows a configuration example of the projection substrate 100 according to this embodiment. Fig. 5 shows an example in which the first surface and the second surface of the projection substrate 100 are arranged substantially parallel to the XY plane. The projection substrate 100 is a substrate for projecting incident projection light onto a display surface as image light. The projection substrate 100 is, for example, a glass substrate. The projection substrate 100 has an incident region 210, a branching region 220, and an exit region 230. Note that Fig. 5 omits the filling material formed on the surface of the projection substrate 100, the components stacked on the surface of the projection substrate 100, and the like. Such filling material and the components stacked on the surface of the projection substrate 100 will be described later.

[0035] <Example of Incident Region 210> The incident region 210 receives projection light for projecting image light and guides the incident projection light toward the branching region 220. Fig. 5 shows an example in which the incident region 210 has a circular shape on a plane substantially parallel to the XY plane, but is not limited to this. The incident region 210 may have any shape, such as an ellipse, a polygon, or a trapezoid, as long as it can guide the projection light toward the branching region 220.

[0036] The incident region 210 has an incident diffraction grating in which a plurality of first grooves 212 are formed at a first period. In other words, the plurality of first grooves 212 are arranged in the same direction on the upper surface of the projection substrate 100 with a predetermined groove width and interval, thereby functioning as a diffraction grating. The incident region 210 has a reflective or transmissive incident diffraction grating and guides projection light toward the branching region 220 by reflective diffraction or transmissive diffraction. The first period of the plurality of first grooves 212 is, for example, in the range of approximately 10 nm to 10 μm.

[0037] The multiple first grooves 212 are arranged, for example, in a direction from the incident region 210 toward the branching region 220. Here, the traveling direction of the projection light from the incident region 210 toward the branching region 220 is defined as a third direction. Fig. 5 shows an example in which the third direction is a direction substantially parallel to the X-axis direction, and the first grooves 212 extending in a direction substantially parallel to the Y-axis direction are arranged in the third direction. Since the projection light is incident on the incident region 210 while converging, the incident region 210 guides the projection light to the branching region 220 so that the projection light has a divergence angle centered on the third direction within the plane of the projection substrate 100.

[0038] <Example of Branching Region 220> The branching region 220 guides a portion of the projection light incident from the entrance region 210 toward the exit region 230. The branching region 220 is provided in a region through which the projection light passes, on a plane substantially parallel to the XY plane. The branching region 220 has a reflective intermediate diffraction grating, and guides the projection light toward the exit region 230 by reflective diffraction. The branching region 220 has, for example, a rectangular shape with the third direction as its longitudinal direction.

[0039] Since the projection light propagates while spreading around the third direction, it is preferable that the branching region 220 has a shape that spreads away from the entrance region 210 and away from the third direction, which is the propagation direction of the projection light passing through the entrance region 210, as it moves away from the entrance region 210. The branching region 220 has, for example, a trapezoidal, fan-shaped, or other shape on a plane substantially parallel to the XY plane. Figure 5 shows an example in which the branching region 220 has a trapezoidal shape. A branching region 220 of this shape can be formed corresponding to a region where the projection light propagates while spreading in the XY plane, and can efficiently guide the projection light.

[0040] The branching region 220 has an intermediate diffraction grating in which a plurality of second grooves 222 are formed at a second period. In other words, the plurality of second grooves 222 are arranged in the same direction on the upper surface of the projection substrate 100 with a predetermined groove width and interval, thereby functioning as a diffraction grating. The branching region 220 functions as, for example, a reflective intermediate diffraction grating and guides the projection light to the emission region 230.

[0041] The second period of the plurality of second groove portions 222 is different from the first period of the plurality of first groove portions 212. It is desirable to select an appropriate second period for guiding the projection light to the emission region 230. The second period is, for example, in the range of about 10 nm to about 10 μm.

[0042] The plurality of second grooves 222 are arranged, for example, in a predetermined direction. For example, the direction from the branching region 220 toward the emission region 230 is defined as the fourth direction, and the angle between the third direction and the fourth direction is defined as the first angle. In this case, the plurality of second grooves 222 are formed in a direction inclined toward the fourth direction by an angle that is half the first angle with respect to the third direction. Figure 5 shows an example in which the fourth direction is substantially parallel to the Y-axis direction, the first angle is substantially 90 degrees, and the plurality of second grooves 222 are arranged in a direction inclined toward the fourth direction by approximately 45 degrees with respect to the third direction.

[0043] The branching region 220 has a plurality of first dividing regions 224 arranged in the traveling direction of the incident projection light. The second grooves 222 formed in the plurality of first dividing regions 224 have different depths. In other words, the second grooves 222 are formed in the branching region 220 so that the proportion of the incident projection light that is guided to the emission region 230 differs for each first dividing region 224.

[0044] It is desirable that the branching region 220 has three or more first divided regions 224. In this way, the branching region 220 is divided into a plurality of first divided regions 224, and the amount of projection light guided to the emission region 230 is varied for each first divided region 224, thereby guiding projection light whose intensity varies depending on the distance from the incidence region 210 to the emission region 230, while adjusting the distribution of the light amount in the direction perpendicular to the traveling direction of the projection light to be approximately constant.

[0045] For example, the second grooves 222 are formed so that the depth of the second grooves 222 provided in one first divided region 224 is greater than the depth of the second grooves 222 provided in a first divided region 224 that is closer to the incident region 210 than the one first divided region 224. In this case, the rate of change in the depth of the second grooves 222 between two adjacent first divided regions 224 among the plurality of first divided regions 224 may be greater the farther away from the incident region 210.

[0046] 5, consider a branch region 220 having three first divided regions 224. Here, the first divided region 224a, which is closest to the incident region 210 among the three first divided regions 224, has a depth of the second groove 222a formed so that approximately one-quarter of the amount of incident projection light is guided to the output region 230. In this case, the remaining approximately three-quarters of the amount of projection light that is incident on the first divided region 224a closest to the incident region 210 is incident on the adjacent first divided region 224b.

[0047] The depth of the second groove 222b of the first divided region 224b second closest to the entrance region 210 is formed so that the second groove 222b guides approximately one-third of the amount of incident projection light to the exit region 230. In other words, the depth of the second groove 222b of the first divided region 224b second closest to the entrance region 210 is formed greater than the depth of the second groove 222a so that the first divided region 224b guides 4 / 3 times the amount of light to the exit region 230 compared to the first divided region 224a closest to the entrance region 210. This first divided region 224b guides approximately one-quarter of the amount of projection light incident on the first divided region 224a closest to the entrance region 210 to the exit region 230.

[0048] The remaining approximately half of the amount of projection light that is incident on the first divided region 224a that is closest to the incident region 210 is incident on the adjacent first divided region 224c. The first divided region 224c that is third closest to the incident region 210 has a depth of the second groove 222c formed so as to guide approximately half of the amount of incident projection light to the output region 230. In other words, the depth of the second groove 222c of the first divided region 224c that is third closest to the incident region 210 is formed greater than the depth of the second groove 222b so as to guide 3 / 2 times the amount of light to the output region 230 compared to the first divided region 224b that is second closest to the incident region 210.

[0049] Furthermore, the rate of change in the depth of the second groove portions 222 of two adjacent first divided regions 224 out of the three first divided regions 224 is formed so that the rate of change increases the farther away from the incident region 210. The first divided region 224c, which is third closest to the incident region 210, guides to the output region 230 approximately one-fourth the amount of projection light that was incident on the first divided region 224a, which is closest to the incident region 210. As in the above example, by varying the amount of projection light guided to the output region 230 for each first divided region 224 to a predetermined value, it can be seen that the branch region 220 can guide the projection light to the output region 230 while maintaining a substantially constant distribution of the amount of projection light guided to the output region 230 corresponding to each first divided region 224.

[0050] <Example of Emission Region 230> The emission region 230 guides at least a portion of the projection light incident from the branch region 220 and emits it as image light from the second surface of the projection substrate 100. Fig. 5 shows an example in which the emission region 230 has a rectangular shape with its longitudinal direction in the X-axis direction on a plane approximately parallel to the XY plane, but this is not limiting. The emission region 230 only needs to be able to guide the projection light and emit it as image light, and may have a shape such as a rectangle, square, or trapezoid with its longitudinal direction in the Y-axis direction.

[0051] The emission region 230 has an emission diffraction grating in which a plurality of third groove portions 232 are formed at a third period. In other words, the plurality of third groove portions 232 are arranged in the same direction on the upper surface of the projection substrate 100 with a predetermined groove width and interval, thereby functioning as a diffraction grating. The emission region 230 has a reflective or transmissive emission diffraction grating and guides image light toward the user's eyes by reflective diffraction or transmissive diffraction.

[0052] The third period of the plurality of third groove portions 232 provided in the emission region 230 is different from the second period of the plurality of second groove portions 222 in the branch region 220. The third period of the plurality of third groove portions 232 in the emission region 230 may be the same as the first period of the plurality of first groove portions 212 in the incidence region 210. In this way, by substantially matching the periods of the diffraction gratings provided in the region where the projection light enters and the region where the image light exits, distortions and the like occurring in the image observed by the user can be reduced. The third period is, for example, in the range of approximately 10 nm to 10 μm.

[0053] The plurality of third grooves 232 are arranged, for example, in a fourth direction from the branching region 220 toward the emission region 230. Fig. 5 shows an example in which the third grooves 232 extending in the third direction are arranged in the fourth direction.

[0054] Like the branching region 220, the emission region 230 has a plurality of second division regions 234 arranged in the traveling direction of the projection light incident from the branching region 220. The third groove portions 232 formed in the plurality of second division regions 234 have different depths. In other words, the third groove portions 232 are formed in the emission region 230 so that the proportion of light that is emitted as image light out of the input projection light differs for each second division region 234.

[0055] It is desirable that the emission region 230 has two or more second divide regions 234. For example, the depth of the third groove portion 232 provided in one second divide region 234 is formed to be greater than the depth of the third groove portion 232 provided in a second divide region 234 that is closer to the branch region 220 than the one second divide region 234. Furthermore, when the emission region 230 has three or more second divide regions 234, the rate of change in the depth of the third groove portion 232 of two adjacent second divide regions 234 may be greater the farther away from the branch region 220.

[0056] As described above, the emission region 230 is divided into a plurality of second divided regions 234, and the amount of light emitted as image light is made different for each second divided region 234. As a result, like the plurality of first divided regions 224 of the branch region 220, the emission region 230 can guide the projection light as image light, and can adjust the distribution of the amount of light across the entire image to be approximately constant when the observer observes the image light as an image.

[0057] As described above, the projection substrate 100 according to this embodiment branches the projection light incident on the entrance region 210 into different proportions for each of the plurality of first divided regions 224 of the branch region 220, and then emits the projection light as image light from the exit region 230. This allows the projection substrate 100 to reduce variations in the brightness of the projected image observed by the user. Furthermore, the projection substrate 100 can further reduce variations in the brightness of the image by emitting image light at different proportions for each of the plurality of second divided regions 234 in the exit region 230 as well.

[0058] Such a projection substrate 100 can be realized by forming a diffraction grating corresponding to the incident region 210, the branching region 220, and the exit region 230 on the front or back surface of a glass substrate or the like. The grooves forming the diffraction grating are made of, for example, resist, resin, or the like.

[0059] It is possible to simplify the optical system by using a two-dimensional diffraction grating that functions as the branching region 220 and the exit region 230. FIG. 6 shows a first modified example of the projection substrate 100 according to this embodiment. The projection substrate 100 of the first modified example shows an example in which a two-dimensional diffraction grating is used. The projection substrate 100 has an entrance region 210 and a two-dimensional diffraction grating 240. Projection light L is incident on the entrance region 210 and exits from the two-dimensional diffraction grating 240 as image light P. In other words, the two-dimensional diffraction grating 240 functions as the branching region 220 and the exit region 230 described in FIG. 2. The two-dimensional diffraction grating 240 is known, so a detailed description thereof will be omitted here.

[0060] The above-described projection substrate 100 can be used to configure the eyeglasses-type terminal 10, etc. However, conventionally, it has been difficult to manufacture the substrates used in the eyeglasses-type terminal 10, etc. A diffraction grating formed on a conventional substrate diffracts incident light by utilizing the difference in refractive index between the material forming the diffraction grating and air.

[0061] Therefore, since the diffraction grating is formed in contact with an air layer, it is vulnerable to impacts and the substrate itself is prone to distortion. Furthermore, vacuum bonding processes and the like cannot be used in the process of forming conventional substrates that are in contact with an air layer. Furthermore, conventional substrates are prone to contamination by foreign matter such as water droplets. To protect such substrates, a complex structure, such as a layer structure to protect the diffraction grating on top of the air layer, was required. Therefore, the projection substrate 100 of this embodiment has a simple structure, is resistant to impacts, is resistant to distortion, can be subjected to vacuum bonding processes and the like, and reduces the intrusion of foreign matter such as water droplets. Such a projection substrate 100 is now described.

[0062] <Example of Cross-Sectional Configuration of Projection Substrate 100> Fig. 7 shows an example of the cross-sectional configuration of the projection substrate 100 according to this embodiment. Fig. 7 shows an example in which an input diffraction grating 310 and an output diffraction grating 320 are formed on the first surface 301 of the projection substrate 100. In other words, an input region 210 and an output region 230 are formed on the first surface 301 of the projection substrate 100. The projection substrate 100 further includes a filler material 330.

[0063] When the projection substrate 100 shown in Fig. 7 is the projection substrate 100 described in Fig. 5, an intermediate diffraction grating (branching region 220) is further formed on the first surface 301 of the projection substrate 100, but the intermediate diffraction grating is not shown in Fig. 7. When the projection substrate 100 shown in Fig. 7 is the projection substrate 100 described in Fig. 6, the exit diffraction grating 320 is a two-dimensional diffraction grating 240, and functions as the branching region 220 and the exit region 230.

[0064] As described above, the input diffraction grating 310 receives projection light for projecting image light and guides at least a portion of the incident projection light toward a predetermined direction within the projection substrate 100. For example, in the case of the projection substrate 100 described in Fig. 5, the input diffraction grating 310 guides the projection light incident toward the intermediate diffraction grating. In addition, in the case of the projection substrate 100 described in Fig. 6, the input diffraction grating 310 guides the projection light incident toward the output diffraction grating 320.

[0065] The output diffraction grating 320 is disposed at a position in a predetermined direction from the input diffraction grating 310, and receives the projection light guided by the input diffraction grating 310, and outputs at least a portion of the input projection light as image light from the second surface 302. For example, in the case of the projection board 100 described in Fig. 5, the output diffraction grating 320 outputs the projection light input from the intermediate diffraction grating as image light from the second surface 302. In addition, in the case of the projection board 100 described in Fig. 6, the output diffraction grating 320 outputs the projection light input from the input diffraction grating 310 as image light from the second surface 302.

[0066] 7, the image light is emitted from a second surface 302 opposite to the first surface 301 of the projection substrate 100. The projection light is incident on the incident diffraction grating 310 from the second surface 302 of the projection substrate 100.

[0067] Filling material 330 fills the grooves of input diffraction grating 310 and output diffraction grating 320. Filling material 330 is a material having a smaller refractive index than input diffraction grating 310 and output diffraction grating 320. Filling material 330 includes, for example, mesoporous silica with a porous structure.

[0068] Mesoporous silica has a porous structure with multiple pores. Furthermore, since mesoporous silica is a spherical material with a diameter of approximately 20 nm, many gaps are formed between the spherical material when it is formed into a film. Since the pores and gaps of such mesoporous silica are filled with air, which has a refractive index of 1, the refractive index of a film formed from mesoporous silica is close to that of air, which is 1. Furthermore, even when mesoporous silica is formed into a film with a thickness similar to that of the grooves of a diffraction grating, there are few areas that block visible light, so the transmittance of visible light and the haze value are also close to those of air.

[0069] The filler material 330 containing such mesoporous silica has, for example, a refractive index of less than 1.2, a visible light transmittance of more than 90%, and a haze value of less than 0.5. Such filler material 330 has properties similar to those of air with respect to visible light. Therefore, even when the grooves of the input diffraction grating 310 and the output diffraction grating 320 are filled with filler material 330, the input diffraction grating 310 and the output diffraction grating 320 can diffract and guide incident light in the same way as when the grooves are not filled with filler material 330.

[0070] As described above, the grooves of the input diffraction grating 310 and the output diffraction grating 320 are filled with the filler material 330, making them less susceptible to damage by impact and less susceptible to the intrusion of foreign matter such as water droplets. The filler material 330 functions to reinforce the input diffraction grating 310 and the output diffraction grating 320, making the projection substrate 100 less susceptible to distortion. Furthermore, because the input diffraction grating 310 and the output diffraction grating 320 do not need to be in contact with an air layer, a vacuum bonding process or the like can be used in the manufacturing process of the projection substrate 100.

[0071] The filler material 330 may fill only the grooves of the input diffraction grating 310 and the output diffraction grating 320, or alternatively, as shown in FIG. 7 , the filler material 330 may be deposited over the entire first surface 301 of the projection substrate 100. In this case, it is desirable that the filler material 330 be deposited to a thickness equal to or greater than a predetermined thickness on the input diffraction grating 310 and the output diffraction grating 320. The predetermined thickness is, for example, about five times the width of the grooves of the input diffraction grating 310 or the output diffraction grating 320. The predetermined thickness is desirably about ten times the width of the grooves of the input diffraction grating 310 or the output diffraction grating 320.

[0072] The incident diffraction grating 310 and the exit diffraction grating 320 are formed on the first surface 301 of the projection substrate 100, opposite the second surface 302. Projection light that passes through the interior of the projection substrate 100 from the second surface 302 is incident on the incident diffraction grating 310. It is desirable for the incident diffraction grating 310 to be able to diffract all of the incident projection light, but some of the light may leak from the first surface 301 to the outside of the projection substrate 100. In this embodiment, this leaked light is called leakage light.

[0073] Such leakage light may enter the eyes of a person facing the user and cause discomfort. However, when the filler material 330 is layered to a thickness equal to or greater than a predetermined thickness on the incident diffraction grating 310, the filler material 330 reinforces the incident diffraction grating 310 while dispersing and reducing the leakage light from the incident diffraction grating 310 within the filler material 330.

[0074] Similarly, the output diffraction grating 320 causes at least a portion of the incident projection light to pass through the inside of the projection substrate 100 and exit from the second surface 302. It is desirable for the output diffraction grating 320 to be able to diffract all of the incident projection light, but some of the light may leak from the first surface 301 to the outside of the projection substrate 100 as leakage light. In this case as well, by stacking the filler material 330 to a thickness equal to or greater than a predetermined thickness on the output diffraction grating 320, the filler material 330 can reinforce the output diffraction grating 320 while dispersing and reducing the leakage light from the output diffraction grating 320 inside the filler material 330.

[0075] As described above, by covering the input diffraction grating 310 and the output diffraction grating 320 with the filler material 330, the filler material 330 can reduce leakage light while reinforcing the input diffraction grating 310 and the output diffraction grating 320. The projection substrate 100 can output incident projection light as image light without the input diffraction grating 310 and the output diffraction grating 320 being in contact with an air layer, and can protect the input diffraction grating 310 and the output diffraction grating 320 without a complex configuration. Next, the projection substrate 100, which has the function of protecting the filler material 330, will be described.

[0076] <Second Modification of Projection Board 100> Figure 8 shows a second modification of the projection board 100 according to the present embodiment. In the projection board 100 of the second modification, components that operate in substantially the same manner as those of the projection board 100 according to the present embodiment shown in Figure 7 are designated by the same reference numerals, and redundant explanations will be omitted. The projection board 100 of the second modification further includes a protective film 340 and an adhesive sheet 350.

[0077] Similar to FIG. 7 , the filler material 330 covers the input diffraction grating 310 and the output diffraction grating 320. The protective film 340 covers and protects the surface of the filler material 330. The protective film 340 is, for example, a triacetyl cellulose (TAC) film. The protective film 340 may also be a cover glass. The adhesive sheet 350 is provided between the protective film 340 and the filler material 330 and bonds the protective film 340 to the filler material 330. The adhesive sheet 350 is, for example, a film-like optical adhesive called OCA (Optical Clear Adhesive).

[0078] In the projection substrate 100 of the second modified example described above, the protective film 340 is attached to the filling material 330 with an adhesive sheet 350. The filling material 330 has a weak cohesive force, which may weaken the film strength. In such cases, the protective film 340 can protect the filling material 330.

[0079] Furthermore, since the surface of the first surface 301 of the projection substrate 100 can be strengthened by the protective film 340, an optical member can be further provided on the surface of the protective film 340 opposite the adhesive sheet 350. The projection substrate 100 may further include, for example, an optical lens on the surface of the protective film 340. One example of the optical lens is a prescription lens for correcting the user's eyes. Alternatively or in addition to this, the projection substrate 100 may further include an optical film having an anti-reflection film.

[0080] As described above, the projection substrate 100 of the second modified example allows a diffraction grating to be easily formed on the substrate, and also allows optical members to be easily attached. Therefore, the eyeglass-type terminal 10 using such a projection substrate 100 can project image light onto the second surface 302, and can also have various other functions. Next, a method for manufacturing such a projection substrate 100 will be described.

[0081] <Example of Manufacturing Flow of Projection Substrate 100> Fig. 9 shows an example of a manufacturing flow of the projection substrate 100 according to this embodiment. Fig. 10 shows an example of the configuration of a process for forming the projection substrate 100 according to this embodiment. First, an input diffraction grating 310 and an output diffraction grating 320 are formed on a first surface 301 of a substrate 300 (S11). The input diffraction grating 310 and the output diffraction grating 320 may be formed by a known method, and detailed description thereof will be omitted here.

[0082] 10A shows an example in which an input diffraction grating 310 and an output diffraction grating 320 are formed on a first surface 301 of a substrate 300 according to this embodiment. An intermediate diffraction grating may also be formed on the first surface 301 of the substrate 300. The output diffraction grating 320 may also be a two-dimensional diffraction grating. When multiple diffraction gratings are formed on the same surface, the process for forming the multiple diffraction gratings can be shared, allowing multiple diffraction gratings to be formed efficiently.

[0083] Next, a liquid containing a filler material with a refractive index smaller than that of the substrate 300 is applied to the formed input diffraction grating 310 and output diffraction grating 320 (S12). The liquid contains mesoporous silica as a filler material and a solvent. The solvent is, for example, one liquid or a mixture of multiple liquids selected from the group consisting of ethanol, methyl ethyl ketone, isobutanol, methanol, and water.

[0084] The liquid is formulated so that the solid content of mesoporous silica is 5% or more and 20% or less. The viscosity of the liquid is preferably adjusted to approximately 20 mPa·s. This liquid is applied to the first surface 301 of the substrate 300 using, for example, a spin coater. The spin coater applies the liquid at, for example, approximately 1000 rpm. By using this liquid, the liquid can be filled into the gaps in the grooves of the input diffraction grating 310 and the output diffraction grating 320.

[0085] Next, the applied liquid agent is dried to form filler material 330 that fills the grooves of incident diffraction grating 310 and exit diffraction grating 320 and has a smaller refractive index than incident diffraction grating 310 and exit diffraction grating 320 (S13). Fig. 10(B) shows an example in which filler material 330 is formed on incident diffraction grating 310 and exit diffraction grating 320 formed on substrate 300 according to this embodiment.

[0086] Next, a protective film 340 is attached to the formed filler material 330 using an adhesive sheet 350 (S14). In this manner, the projection substrate 100 can be formed. Fig. 10(C) shows an example in which the projection substrate 100 is formed by attaching the protective film 340 to the substrate 300 according to this embodiment. According to the above operational flow, a diffraction grating for projecting image light onto the second surface 302 of the substrate 300 can be easily formed.

[0087] In the above description of the projection substrate 100 according to the present embodiment, the input diffraction grating 310 and the output diffraction grating 320 are formed on the first surface 301 of the projection substrate 100, but the present invention is not limited to this. For example, at least one of the input diffraction grating 310 and the output diffraction grating 320 may be formed on the second surface 302 of the projection substrate 100.

[0088] 11 shows a third modified example of the projection substrate 100 according to the present embodiment. The projection substrate 100 of the third modified example shows an example in which an output diffraction grating 320 is formed on the second surface 302 of the projection substrate 100. Also, this shows an example in which a filler material 330 is formed so as to cover the first surface 301 and the second surface 302 of the projection substrate 100.

[0089] Alternatively, the exit grating 320 may be formed on the first surface 301 of the projection substrate 100, and the entrance grating 310 may be formed on the second surface 302 of the projection substrate 100. Alternatively, the intermediate grating may be formed on the second surface 302 of the projection substrate 100.

[0090] 12 shows a fourth modified example of the projection substrate 100 according to the present embodiment. The projection substrate 100 of the fourth modified example shows an example in which an input diffraction grating 310 and an output diffraction grating 320 are formed on the second surface 302 of the projection substrate 100. Also shown is an example in which a filler material 330 is formed so as to cover the first surface 301 and the second surface 302 of the projection substrate 100. Although no diffraction grating is formed on the first surface 301 of the projection substrate 100, by laminating the filler material 330, it is possible to reduce leakage light output from the first surface 301 of the projection substrate 100.

[0091] In the above-described third and fourth modified projection substrates 100, examples have been described in which the filler material 330 is formed on the first surface 301 and the second surface 302 of the projection substrate 100. The third and fourth modified projection substrates 100 may further include a protective film 340 and an adhesive sheet 350 for protecting the filler material 330 on the first surface 301 and / or the second surface 302.

[0092] In the projection board 100 according to the present embodiment, an example has been described in which projection light incident on the second surface 302 from the outside is incident on the incident diffraction grating 310. However, the present invention is not limited to this. Alternatively, projection light incident on the first surface 301 from the outside may be incident on the incident diffraction grating 310.

[0093] In the above embodiment, the projection substrate 100 has been described as an example of a substrate on which a diffraction grating is formed so that no air gap is formed on either side of the diffraction grating, but the present invention is not limited to this. When one or more diffraction gratings are formed on a substrate, the diffraction grating can be reinforced by using the filler material 330 according to this embodiment.

[0094] For example, instead of the projection substrate 100, a diffraction substrate on which a single diffraction grating is formed may include the filler material 330. The diffraction substrate is a substrate for diffracting incident light. The diffraction grating receives incident light, diffracts at least a portion of the incident light, and emits the light to the outside of the substrate. Such a diffraction grating may be formed, for example, on a glass substrate or the like using a resist, resin, or the like. In this case, if the diffraction grating is formed so as to be in contact with an air layer, as in the above-mentioned input diffraction grating 310 and output region 230, it may become vulnerable to impacts and the substrate itself may be easily distorted.

[0095] Therefore, by forming a filler material 330 in the grooves of such a diffraction grating, it is possible to make it less likely to break when subjected to an impact and also to reinforce the substrate, making it less likely to distort. Furthermore, by forming the filler material 330 so as to cover the diffraction grating, it is possible to disperse and reduce stray light components generated by the diffraction grating.

[0096] <First Configuration Example of Lens Unit L> As described above, the projection substrate 100 according to this embodiment may further include an optical lens on the surface of the protective film 340, and may also function as a lens unit (prescription lens) for correcting the user's eyes. A first configuration example of such a lens unit L is shown in Fig. 13. The lens unit L (projection substrate 100) includes a substrate 300, a filler material 330, a first protective film 341, a second protective film 342, an adhesive sheet 350, a first optical lens 360, and a second optical lens 370.

[0097] The substrate 300, the filling material 330, the first protective film 341, the second protective film 342, and the adhesive sheet 350 have already been described, so a duplicated description will be omitted here. The projection substrate 100 shown in Figure 13 shows an example in which the above-mentioned filling material 330, the protective film 340 (the first protective film 341 and the second protective film 342), and the adhesive sheet 350 are provided on both sides of the substrate 300.

[0098] Here, the protective film 340 provided on the first surface 301 of the substrate 300 is referred to as a first protective film 341, and the protective film 340 provided on the second surface 302 of the substrate 300 is referred to as a second protective film 342. In other words, the first protective film 341 covers the surface of the filling material 330 formed on the first surface 301 of the substrate 300, and the second protective film 342 covers the surface of the filling material 330 formed on the second surface 302 of the substrate 300.

[0099] The first optical lens 360 is provided on the surface of the first protective film 341 opposite to the substrate 300. The second optical lens 370 is provided on the surface of the second protective film 342 opposite to the substrate 300. The power of the first optical lens 360 is D1, and the power of the second optical lens 370 is D2.

[0100] Furthermore, the diopter of the image shown by the image light emitted from the output diffraction grating 320 is D", the diopter of the eye of the user observing the image light emitted from the output diffraction grating 320 is D, and the distance between the first optical lens 360 and the second optical lens 370 is d. In this case, the diopter D1 of the first optical lens 360 and the diopter D2 of the second optical lens 370 satisfy the following equations. [Equation 1] D1=(D+D") / (1+d·D"), D2=-D".

[0101] This allows the lens unit L to function as a lens for the right eye and / or a lens for the left eye to correct the user's eyes. Furthermore, the lens unit L can be configured to have no air gap while protecting the diffraction grating provided on the substrate 300, making it shock-resistant and easy to handle. For example, using such a lens unit L, the eyeglass-type terminal 10 shown in FIG. 1 can be easily assembled.

[0102] Depending on the eyeglasses-type terminal 10, if the optical lens of the lens unit L is not positioned accurately in the frame 110 of the eyeglasses-type terminal 10, it may be difficult for the user to view the projected image and / or the outside world scenery. Therefore, the size of the substrate 300 of the lens unit L may be made different from the size of the optical lens, thereby making it easier to position the lens unit L in the frame 110. Such a lens unit L will be described next.

[0103] <Second Configuration Example of Lens Unit L> Fig. 14 shows a second configuration example of the lens unit L according to this embodiment. Fig. 14 shows a part of the frame 110 of the eyeglasses-type terminal 10. In other words, Fig. 14 shows the AA' cross section of the eyeglasses-type terminal 10 shown in Fig. 1. In the lens unit L of the second configuration example, parts that operate in substantially the same manner as in the lens unit L of the first configuration example shown in Fig. 13 are given the same reference numerals, and duplicate explanations will be omitted.

[0104] The lens unit L is formed so that the lengths of the substrate 300, the first protective film 341, and the second protective film 342 are a predetermined first distance in a predetermined width direction (e.g., the Y direction in FIG. 14 ) parallel to the first surface 301 of the substrate 300, and the lengths of the optical lenses are formed to be lengths different from the first distance. The example in FIG. 14 shows an example in which the lengths of the first optical lens 360 and the second optical lens 370 are formed to be longer than the first distance. Note that the lengths of the first optical lens 360 and the second optical lens 370 may be the same distance, or alternatively, may be different distances. FIG. 14 shows an example in which the lengths of the first optical lens 360 and the second optical lens 370 are the same second distance.

[0105] The lens unit L is fixed to the frame 110. The frame 110 has a main body 111 and a cap 112. Fig. 14 shows an example in which the cap 112 is provided on each of the first surface 301 side and the second surface 302 side of the substrate 300.

[0106] The main body 111 has a convex portion 113 that faces the side surface of the lens unit L in the Y direction. When viewed from the Z direction, the convex portion 113 forms a first fixing hole 114 into which the lens unit L is fitted to fix the lens unit L. In other words, the first fixing hole 114 has a length corresponding to the first distance in the width direction parallel to the first surface 301 of the substrate 300, and a depth corresponding to the thickness of the portion of the lens unit L excluding the optical lens in the direction perpendicular to the first surface 301 of the substrate 300.

[0107] The main body 111 also has a first recess 115 and a second recess 117 formed adjacent to the protrusion 113. When viewed from the Z direction, the first recess 115 forms a second fixing hole 116 into which the first optical lens 360 is fitted to fix the first optical lens 360. In other words, the second fixing hole 116 has a length corresponding to the length of the first optical lens 360 in the width direction parallel to the first surface 301 of the substrate 300, and a depth corresponding to the thickness of the end of the first optical lens 360 in the direction perpendicular to the first surface 301 of the substrate 300.

[0108] Similar to the first recess 115, when viewed from the Z direction, the second recess 117 forms a third fixing hole 118 into which the second optical lens 370 is fitted to fix the second optical lens 370. In other words, the third fixing hole 118 has a length corresponding to the length of the second optical lens 370 in the width direction parallel to the first surface 301 of the substrate 300, and a depth corresponding to the thickness of the end of the second optical lens 370 in the direction perpendicular to the first surface 301 of the substrate 300.

[0109] 15 shows a schematic configuration of the process of assembling the eyeglass-type terminal 10 according to this embodiment. For example, a worker fits a component, in which the first protective film 341 and the second protective film 342 are attached to the substrate 300, into the first fixing hole 114 of the frame 110. This allows the worker to complete the positioning of the component, in which the first protective film 341 and the second protective film 342 are attached to the substrate 300, in the frame 110.

[0110] For example, the worker fits the first optical lens 360 into the second fixing hole 116 of the frame 110 and attaches the cap 112 to the frame 110 to fix the first optical lens 360. The worker may also fix the first optical lens 360 to the first protective film 341 and / or the second fixing hole 116 by adhesive. This allows the worker to complete the positioning of the first optical lens 360 on the frame 110.

[0111] For example, the worker fits the second optical lens 370 into the third fixing hole 118 of the frame 110 and attaches the cap 112 to the frame 110 to fix the second optical lens 370. The worker may also fix the second optical lens 370 to the second protective film 342 and / or the third fixing hole 118 by adhesive. This allows the worker to complete the positioning of the second optical lens 370 in the frame 110.

[0112] As described above, the lens unit L according to this embodiment improves the impact resistance of the projection substrate 100 on which the diffraction grating is formed, and makes it easy to handle the projection substrate 100. Furthermore, by using such a projection substrate 100 (lens unit L) and the frame 110 according to this embodiment, the eyeglass-type terminal 10 can be easily assembled.

[0113] In the above-described lens unit L according to the present embodiment, an example has been described in which the lengths of the first optical lens 360 and the second optical lens 370 are formed longer than the first distance, but the present invention is not limited to this. Alternatively, the optical lens length of at least one of the first optical lens 360 and the second optical lens 370 may be formed shorter than the first distance. Such a lens unit L will now be described.

[0114] <Third Configuration Example of Lens Unit L> Fig. 16 shows a third configuration example of the lens unit L according to this embodiment. In the lens unit L of the third configuration example, parts that operate in substantially the same manner as in the lens unit L of the first configuration example shown in Fig. 13 and the lens unit L of the second configuration example shown in Fig. 14 are assigned the same reference numerals, and redundant explanations will be omitted.

[0115] The lens unit L of the third configuration example is formed so that the length of the second optical lens 370 in a predetermined width direction (Y direction) is a third distance that is smaller than the first distance and the second distance. Furthermore, the main body 111 of the frame 110 has a second convex portion 119 that faces the side surface of the lens unit L in the Y direction instead of the second concave portion 117. When viewed from the Z direction, the second convex portion 119 forms a third fixing hole 118 into which the second optical lens 370 is fitted to fix the second optical lens 370.

[0116] In other words, like the third fixing hole 118 of the lens unit L of the second configuration example, the third fixing hole 118 of the lens unit L of the third configuration example has a length corresponding to the length of the second optical lens 370 and a depth corresponding to the thickness of the second optical lens 370. Furthermore, the frame 110 is provided with a cap 112 on the first surface 301 side of the substrate 300, and the cap 112 on the second surface 302 side may not be provided.

[0117] When using the lens unit L and frame 110 of the third configuration example described above, the worker or the like first fits the second optical lens 370 into the third fixing hole 118 of the frame 110. The worker may also fix the third fixing hole 118 and the second optical lens 370 by adhesive. This allows the worker to complete the positioning of the second optical lens 370 in the frame 110.

[0118] Next, the worker or the like fits the component, with the first protective film 341 and the second protective film 342 attached to the substrate 300, into the first fixing hole 114 of the frame 110. The worker may also fix the second protective film 342 and the second optical lens 370 by adhesive bonding. This allows the worker to complete the positioning of the second optical lens 370 in the frame 110.

[0119] Next, the worker or the like fits the first optical lens 360 into the second fixing hole 116 of the frame 110, and attaches the cap 112 to the frame 110 to fix the first optical lens 360. The worker may also fix the first optical lens 360 to the first protective film 341 and / or the second fixing hole 116 by adhesive. This allows the worker to complete the positioning of the first optical lens 360 in the frame 110.

[0120] As described above, by using the lens unit L and frame 110 of the third configuration example, the eyeglass-type terminal 10 can be easily assembled. Note that, while the configuration example of Fig. 16 shows an example in which the length of the second optical lens 370 is the third distance that is smaller than the first distance and the second distance, instead, the length of the first optical lens 360 may be the third distance that is smaller than the first distance and the second distance. Furthermore, the lengths of the first optical lens 360 and the second optical lens 370 may be a distance that is smaller than the first distance.

[0121] Although the above description has been given of an example in which the lens unit L without an air gap is used to position the first optical lens 360 and the second optical lens 370 in the frame 110 according to the present embodiment, the present invention is not limited to this. Even if a lens unit L with an air gap is used, the first optical lens 360 and the second optical lens 370 can be easily positioned in the same way.

[0122] <Lens unit L having an air gap> Figure 17 shows an example of the configuration of a lens unit L having an air gap 390 according to this embodiment. In the lens unit L shown in Figure 17, components that operate in substantially the same manner as those in the lens unit L of the first configuration example shown in Figure 13 are designated by the same reference numerals, and duplicated explanations will be omitted. The lens unit L having the air gap 390 does not include the filler material 330. The first protective film 341 and the second protective film 342 are attached to the substrate 300 via a ring-shaped adapter 380. As a result, air gaps 390 are formed between the substrate 300 and the first protective film 341, and between the substrate 300 and the second protective film 342, respectively.

[0123] Even in the lens unit L having the above air gap 390, by making the lengths of the substrate 300, the first protective film 341, and the second protective film 342, and the lengths of the first optical lens 360 and the second optical lens 370 different in the width direction parallel to the first surface 301 of the substrate 300, the positioning of the first optical lens 360 and the second optical lens 370 in the frame 110 of the eyeglass-type terminal 10 can be easily performed.

[0124] Although the lens unit L according to the present embodiment has been described above as including two optical lenses, the first optical lens 360 and the second optical lens 370, the present invention is not limited to this. Alternatively, the lens unit L may be configured to include either the first optical lens 360 or the second optical lens 370. Furthermore, the lens unit L may be configured to include three or more optical lenses.

[0125] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating in any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments.

[0126] REFERENCE SIGNS LIST 10 Eyeglass-type terminal 20 Input light beam 30 Output light beam bundle 100 Projection substrate 110 Frame 111 Main body 112 Cap 113 Convex portion 114 First fixing hole 115 First recess 116 Second fixing hole 117 Second recess 118 Third fixing hole 119 Second convex portion 120 Projection portion 210 Incident region 212 First groove portion 220 Branching region 222 Second groove portion 224 First division region 230 Outgoing region 232 Third groove portion 234 Second division region 240 Two-dimensional diffraction grating 300 Substrate 301 First surface 302 Second surface 310 Incident diffraction grating 320 Outgoing diffraction grating 330 Filling material 340 Protective film 341 First protective film 342 Second protective film 350 adhesive sheet 360 first optical lens 370 second optical lens 380 adapter 390 air gap

Claims

1. A projection substrate for projecting image light, comprising: a substrate; an incident diffraction grating provided on the substrate, onto which projection light for projecting the image light is incident and which guides at least a portion of the incident projection light in a predetermined direction within the substrate; an exit diffraction grating provided on the substrate, onto which the projection light guided by the incident diffraction grating is incident and which outputs at least a portion of the incident projection light as the image light; a filler material which fills grooves of the incident diffraction grating and the exit diffraction grating and has a refractive index smaller than those of the incident diffraction grating and the exit diffraction grating; a protective film which covers and protects the surface of the filler material; and an optical lens provided on the surface of the protective film opposite the substrate.

2. The projection substrate according to claim 1, wherein the filling material comprises mesoporous silica having a porous structure.

3. The projection substrate according to claim 1, further comprising an adhesive sheet provided between said protective film and said filling material, said adhesive sheet adhering said protective film to said filling material.

4. The projection substrate according to claim 1, wherein the filling material is provided on a first surface of the substrate and a second surface of the substrate opposite to the first surface.

5. A projection substrate as described in claim 4, wherein the protective film comprises a first protective film covering the surface of the filling material formed on the first surface of the substrate, and a second protective film covering the surface of the filling material formed on the second surface of the substrate, and the optical lens comprises a first optical lens provided on the surface of the first protective film opposite to the substrate, and a second optical lens provided on the surface of the second protective film opposite to the substrate.

6. The projection board according to claim 5, wherein the diopter of the image shown by the image light emitted by the output diffraction grating is D", the diopter of the eye of the user observing the image light emitted by the output diffraction grating is D, and the distance between the first optical lens and the second optical lens is d, the diopter D1 of the first optical lens and the diopter D2 of the second optical lens satisfy the following equations: D1 = (D + D") / (1 + d D"), D2 = -D".

7. The projection board according to claim 1, wherein the lengths of the substrate and the protective film are formed to be a predetermined first distance in a predetermined width direction parallel to the first surface of the substrate, and the length of the optical lens is formed to be a length different from the first distance.

8. A glasses-type terminal worn by a user, comprising: the projection board according to any one of claims 1 to 7, which is provided as at least one of a lens for the user's right eye and a lens for the user's left eye and projects the image light in the direction of the user's eye; a frame that fixes the projection board; and a projection unit that is provided on the frame and irradiates the projection light onto the incident diffraction grating of the projection board.

9. The glasses-type terminal according to claim 8, wherein the projection substrate is formed so that the lengths of the substrate and the protective film are a predetermined first distance in a predetermined width direction parallel to the first surface of the substrate, and the length of the optical lens is formed to a length different from the first distance, and the frame has: a first fixing hole for fixing the projection substrate, the first fixing hole having a length corresponding to the first distance in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the projection substrate in a direction perpendicular to the first surface of the substrate; and a second fixing hole for fixing the optical lens, the second fixing hole being formed adjacent to the first fixing hole on the side of at least one of the first surface and a second surface opposite to the first surface of the substrate, the second fixing hole having a length corresponding to the length of the optical lens in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the optical lens in a direction perpendicular to the first surface of the substrate.

10. In the projection substrate, the filling material is provided on a first surface of the substrate and a second surface of the substrate opposite to the first surface, the protective film has a first protective film covering a surface of the filling material formed on the first surface of the substrate and a second protective film covering a surface of the filling material formed on the second surface of the substrate, the optical lens has a first optical lens provided on a surface of the first protective film opposite to the substrate and a second optical lens provided on a surface of the second protective film opposite to the substrate, the substrate, the first protective film, and the second protective film are formed so that lengths of the substrate, the first protective film, and the second protective film are a predetermined first distance in a predetermined width direction parallel to the first surface of the substrate, the length of the first optical lens is a second distance different from the first distance, and the length of the second optical lens is a third distance different from the first distance, the frame has a length corresponding to the first distance in the width direction parallel to the first surface of the substrate and a first fixing hole for fixing the projection substrate, the first fixing hole having a depth corresponding to a thickness of the projection substrate in a direction perpendicular to the first surface of the substrate, 9. The eyeglass-type terminal according to claim 8, comprising: a second fixing hole for fixing the first optical lens, formed adjacent to the first fixing hole on the side of the first surface of the substrate, the second fixing hole having a length corresponding to a length of the first optical lens in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the first optical lens in the direction perpendicular to the first surface of the substrate; and a third fixing hole for fixing the second optical lens, formed adjacent to the first fixing hole on the side of the second surface of the substrate, the third fixing hole having a length corresponding to a length of the second optical lens in the width direction parallel to the first surface of the substrate and a depth corresponding to a thickness of the second optical lens in the direction perpendicular to the first surface of the substrate.

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