Glasses-type device

Description

[Technical field]

[0001] The present invention relates to a projection optical system and an eyeglass-type terminal. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there are known glasses-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 Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-207686 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such devices, the optical system is often complicated because it is built into a limited space. Also, part of the image light projected for the user to view may leak out as light in a direction different from that of the user, making the user's eyes appear to be glowing, for example.

[0005] The present invention has been made in consideration of these points, and has an object to reduce leakage light of image light observed by a user with a simple configuration. [Means for solving the problem]

[0006] In a first aspect of the present invention, a semiconductor device is provided having an optical waveguide and a first surface. The present invention provides a projection optical system comprising: a projection substrate for transmitting at least a portion of incident light to a second substrate opposite the first substrate, while projecting image light onto the second substrate; and a polarization reduction plate disposed on the first substrate side of the projection substrate relative to the optical waveguide section via an air layer, covering at least a portion of the optical waveguide section, and reducing light in the polarization direction of the image light leaking from the first substrate side of the projection substrate, wherein the optical waveguide section guides at least a portion of the projection light for projecting the image light, and emits the projection light from the second substrate side as the image light.

[0007] The polarisation reduction plate may include a polarising filter disposed opposite the first surface of the projection substrate.

[0008] The polarization reduction plate may have a protective substrate disposed opposite the first surface of the projection substrate, and a polarizing film coated on at least one of a third surface of the protective substrate opposite the projection substrate and a fourth surface facing the projection substrate.

[0009] The optical waveguide section may have an input diffraction grating, an input region into which projection light for projecting the image light is incident and which guides the input projection light into the interior of the projection substrate, and an output region having an output diffraction grating, which guides at least a portion of the projection light incident from the input region and outputs it from the second surface as the image light, and the polarization reduction plate may cover at least a portion of the output diffraction grating.

[0010] The optical waveguide may further have an intermediate region that includes an intermediate diffraction grating and guides a portion of the projection light incident from the entrance region toward the exit region, the entrance diffraction grating having a plurality of first groove portions formed at a first period, the intermediate diffraction grating having a plurality of second groove portions formed at a second period, and the exit diffraction grating having a plurality of third groove portions formed at a third period.

[0011] In a second aspect of the present invention, there is provided a glasses-type terminal worn by a user, comprising: the projection optical system of the first aspect, which is provided as at least one of a lens for the right eye and a lens for the left eye of the user, and which projects the image light onto the second surface while transmitting at least a portion of the light incident from the first surface to 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 an entrance area of ​​the optical waveguide of the projection substrate to project the image light onto an exit area of ​​the optical waveguide.

[0012] The projection unit may have a polarization adjustment unit that adjusts the polarization direction of the projection light irradiated to the incident area, and the polarization adjustment unit may adjust the polarization direction of the image light leaking from the first surface of the projection substrate to match the polarization direction in which the polarization reduction plate reduces the light intensity.

[0013] A plurality of the projection substrates are fixed to the frame, the polarization reduction plate is provided on the side of the plurality of projection substrates opposite the user, the projection unit irradiates the projection light of different wavelengths onto the entrance area provided on each of the plurality of projection substrates, the exit areas provided on each of the plurality of projection substrates at least partially overlap in a planar view, and the image light corresponding to the projection light irradiated from the projection unit onto each of the plurality of entrance areas is emitted from the second surface of each of the plurality of projection substrates to the eyes of the user.

[0014] The projection unit has a polarization adjustment unit that adjusts the polarization direction of at least one of the multiple projection lights irradiated to the incident area, and the polarization adjustment unit may adjust the polarization direction of the image light corresponding to at least one of the projection lights whose polarization direction has been adjusted by the polarization adjustment unit among the multiple image lights leaking from the first surfaces of each of the multiple projection substrates to match the polarization direction in which the polarization reduction plate reduces the light intensity. Effect of the Invention

[0015] According to the present invention, it is possible to reduce leakage light of image light observed by a user with a simple configuration. [Brief description of the drawings]

[0016] [Figure 1] 1 shows a first configuration example of a glasses-type terminal 10 according to the present embodiment. [Diagram 2] 2 shows an outline of the optical path of projected light in an eyeglass-type terminal 10 according to the present embodiment. [Diagram 3] 1 shows an outline of the optical path of projection light on a projection substrate 100 according to the present embodiment. [Figure 4] 1 shows an example of projection light that the projection unit 120 according to the present embodiment irradiates onto the projection substrate 100, and image light that the projection substrate 100 emits. [Diagram 5] 1 shows an example of the configuration of a projection substrate 100 according to the present embodiment. [Figure 6] 2 shows a second configuration example of the glasses-type terminal 10 according to the present embodiment. [Figure 7] 13 shows a third configuration example of the glasses-type terminal 10 according to the present embodiment. [Figure 8] 13 shows a fourth configuration example of the glasses-type terminal 10 according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] <First Configuration Example of Glasses-Type Terminal 10> FIG. 1 shows a first configuration example of a glasses-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 glasses-type terminal 10 is, for example, a wearable device worn by a user. The glasses-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 glasses-type terminal 10 includes a projection optical system 50, a frame 110, and a projection unit 120.

[0018] The projection optical system 50 includes a projection substrate 100 and a polarization reduction plate 310. In Fig. 1, the projection substrate 100 of the projection optical system 50 is shown, and the polarization reduction plate 310 is omitted. The polarization reduction plate 310 will be described later.

[0019] The projection substrate 100 has an optical waveguide 200 and receives light from a first surface. The projection substrate 100 projects image light onto the second surface while transmitting at least a portion of the light toward the user's eyes. Here, the first surface of the projection substrate 100 is a surface that faces away from the user when the user wears the glasses-type terminal 10. The second surface of the projection substrate 100 is a surface that faces the user when the user wears the glasses-type terminal 10. FIG. 1 shows an example in which the first surface and the second surface of the projection substrate 100 are arranged approximately parallel to the XY plane.

[0020] The projection substrate 100 is, for example, a glass substrate on which an optical waveguide 200 is formed. The optical waveguide section 200 guides at least a part of the projection light for projecting the image light incident on the second surface of the projection substrate 100, and emits the image light from the second surface. The projection substrate 100 will be described later.

[0021] The frame 110 fixes the projection optical system 50. The frame 110 is provided with the projection optical system 50 as at least one of a lens for the right eye and a lens for the left eye of a user. Fig. 1 shows an example in which the frame 110 is provided with a projection optical system 50a as a lens for the right eye of a user, and a projection optical system 50b as a lens for the left eye.

[0022] Alternatively, the frame 110 may be provided with one projection optical system 50 as a lens for the user's right eye or left eye. The frame 110 may also be provided with one projection optical system 50 as lenses for both eyes of the user. In this case, the frame 110 may have a goggle shape. The frame 110 has parts such as temples and a strap so that the user can wear the eyeglass-type terminal 10.

[0023] The projection unit 120 is provided on the frame 110, and irradiates projection light toward the projection optical system 50 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 the projection optical system 50a (projection substrate 100a) with projection light L1 and a projection unit 120b for irradiating the projection optical system 50b (projection substrate 100b) with projection light L2 are provided on the frame 110.

[0024] The projection unit 120 may be provided at a portion of the frame 110 where the projection optical system 50 is fixed, or may be provided at a temple or the like of the frame 110. It is desirable that the projection unit 120 is provided so as to be integrated with the frame 110. For example, the projection unit 120 irradiates the projection optical system 50 with projection light including one wavelength, allowing the user to observe a monochromatic image. The projection unit 120 may also irradiate the projection optical system 50 with projection light including multiple wavelengths, allowing the user to observe an image including multiple colors.

[0025] The following describes such a projection optical system 50. First, the operation of the projection substrate 100 of the projection optical system 50 will be described, and the polarization reduction plate 310 will be described later.

[0026] 2 shows an outline of the optical path of the projection light in the eyeglass-type terminal 10 according to this embodiment. The projection unit 120 irradiates the projection light onto an incident region 210 of the optical waveguide unit 200 of the projection substrate 100. The incident region 210 guides the projection light within the substrate of the projection substrate 100. Then, at least a part of the projection light guided within the substrate is emitted as image light from an exit region 230 of the optical waveguide unit 200. The incident region 210 and the exit region 230 will be described later.

[0027] 3 shows an outline of the optical path of the projection light on the projection substrate 100 according to this embodiment. As will be described later, the optical waveguide section 200 has an entrance region 210, an intermediate region 220, and an exit region 230. The projection light L enters the entrance region 210, passes through the intermediate region 220, and exits from the exit region 230 as image light P. The intermediate region 220 guides the projection light L part by part to the exit region 230 as the projection light L travels away from the entrance region 210.

[0028] Similarly, as the projection light L travels away from the intermediate region 220, the emission region 230 also emits a portion of the projection light L as a part of the image light P. In this way, the projection substrate 100 emits the projection light L incident on the entrance region 210 from the emission region 230 as the image light P.

[0029] Here, consider an example in which the intermediate region 220 guides the projection light L to the emission region 230 at a constant rate throughout the entire region of the intermediate region 220. In this case, the amount of the projection light L decreases as the projection light L travels away from the entrance region 210, so the intensity of the projection light L incident on the emission region 230 from the intermediate region 220 may differ depending on the distance from the entrance region 210.

[0030] Similarly, consider an example in which the emission region 230 emits the projection light L as image light P at a constant rate throughout the entire region of the emission region 230. In this case, the amount of the projection light L decreases as the projection light L travels away from the intermediate region 220, so the intensity of the image light P emitted from the emission region 230 may differ depending on the distance from the entrance region 210 and the distance from the emission region 230. For example, the brightness may gradually decrease from the upper left pixel to the lower right pixel of the image projected by the emission region 230. The projection substrate 100 according to this embodiment reduces such variations in brightness.

[0031] <Example of projection light and image light> FIG. 4 shows an example of the projection light L that the projection unit 120 according to this embodiment irradiates onto the projection substrate 100 and the image light P that the projection substrate 100 emits. 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 a screen or the like is installed on a surface approximately parallel to the XY plane and the projection light L is projected, an image M1 to be observed by the user is displayed on the screen. The image to be shown to the user is, for example, an AR (Augmented Reality) image or a VR (Virtual Reality) 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 approximately parallel to the XY plane.

[0032] 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. In addition, in FIG. 4, five light rays out of the multiple light rays irradiated 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.

[0033] The projection unit 120, for example, irradiates such projection light L onto the entrance area 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 area 210 passes through the intermediate area 220 and is emitted from the exit area 230 as image light P. The image light P is emitted from the exit area 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 an image M2 on the retina of the user's eye. In this manner, the image light P includes a plurality of light beams that are focused as an image M2.

[0034] 4, five of the multiple light beams that are irradiated 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 light beams 30. For example, the light beam that forms an image as the lower right pixel of the image is designated as the first output light beam 30a, the light beam that forms an image as the upper right pixel of the image is designated as the second output light beam 30b, the light beam that forms an image as the central pixel of the image is designated as the third output light beam 30c, the light beam that forms an image as the lower left pixel of the image is designated as the fourth output light beam 30d, and the light beam that forms an image as the upper left pixel of the image is designated as the fifth output light beam 30e.

[0035] Each light beam corresponds to each of the multiple input light beams 20 incident from the projection unit 120. For example, the first output light beam 30a corresponds to the first input light beam 20a, and includes multiple light beams generated by multiple branching and multiple diffractions of the first input light beam 20a between the entrance region 210 and the exit region 230 of the projection substrate 100. Similarly, the second output light beam 30b corresponds to the second input light beam 20b, the third output light beam 30c corresponds to the third input light beam 20c, the fourth output light beam 30d corresponds to the fourth input light beam 20d, and the fifth output light beam 30e corresponds to the fifth input light beam 20e.

[0036] 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 irradiated by the projection unit 120. This allows the user wearing the glasses-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.

[0037] 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. The image M1 projected by the projection light L may be a still image, or alternatively, may be a moving image. Next, the projection substrate 100 that emits the image light P corresponding to the incident projection light L as described above will be described.

[0038] <Configuration example of projection substrate 100> Fig. 5 shows a configuration example of the projection substrate 100 according to this embodiment. Fig. 3 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 having an optical waveguide section 200 for transmitting at least a part of the light incident from the first surface to the second surface opposite to the first surface, and projecting image light onto the second surface. The projection substrate 100 is, for example, a glass substrate. The projection substrate 100 includes an optical waveguide section 200 having an entrance region 210, an intermediate region 220, and an exit region 230.

[0039] <Example of the entrance region 210> The incident region 210 receives projection light for projecting image light and guides the incident projection light toward the intermediate 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 to the intermediate region 220.

[0040] 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 the projection light in the direction of the intermediate 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 about 10 nm to about 10 μm.

[0041] The multiple first grooves 212 are arranged, for example, in a direction from the entrance region 210 toward the intermediate region 220. Here, the traveling direction of the projection light from the entrance region 210 toward the intermediate region 220 is defined as the first direction. FIG. 5 shows an example in which the first 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 first direction. Since the projection light is incident on the entrance region 210 while converging, the entrance region 210 guides the projection light to the intermediate region 220 so as to have a divergence angle centered on the first direction within the plane of the projection substrate 100.

[0042] <Example of intermediate region 220> The intermediate region 220 guides a portion of the projection light incident from the entrance region 210 toward the exit region 230. The intermediate region 220 is provided in a region through which the projection light passes, on a surface substantially parallel to the XY plane. The intermediate region 220 has a reflective intermediate diffraction grating, and guides the projection light toward the exit region 230 by reflective diffraction. The intermediate region 220 has, for example, a rectangular shape with the first direction as the longitudinal direction.

[0043] Since the projection light travels while spreading around the first direction, it is preferable that the intermediate region 220 has a shape that spreads away from the first direction, which is the traveling direction of the projection light passing through the entrance region 210, as it moves away from the entrance region 210. The intermediate region 220 has a trapezoidal, fan-shaped, or other shape on a plane substantially parallel to the XY plane, for example. FIG. 5 shows an example in which the intermediate region 220 has a trapezoidal shape. The intermediate region 220 having such a shape can be formed corresponding to a region where the projection light travels while spreading on the XY plane, and can efficiently guide the projection light.

[0044] The intermediate region 220 has an intermediate diffraction grating in which a plurality of second groove portions 222 are formed at a second period. In other words, the plurality of second groove portions 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 intermediate region 220 functions as, for example, a reflective intermediate diffraction grating, and guides the projection light to the emission region 230.

[0045] 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.

[0046] The second grooves 222 are arranged in a predetermined direction, for example. For example, the direction from the intermediate region 220 toward the emission region 230 is the second direction, and the angle between the first direction and the second direction is the first angle. In this case, the second grooves 222 are formed in a direction inclined toward the second direction by an angle of 1 / 2 the first angle with respect to the first direction. FIG. 5 shows an example in which the second direction is substantially parallel to the Y-axis direction, the first angle is substantially 90 degrees, and the second grooves 222 are arranged in a direction inclined toward the second direction by substantially 45 degrees with respect to the first direction.

[0047] The intermediate region 220 has a plurality of first divided regions 224 arranged in the traveling direction of the incident projection light. The second grooves 222 formed in the plurality of first divided regions 224 have different depths. In other words, the second grooves 222 are formed in the intermediate region 220 such that the proportion of light guided to the emission region 230 out of the input projection light differs for each first divided region 224.

[0048] It is desirable for the intermediate region 220 to have three or more first divided regions 224. In this way, the intermediate 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 made different for each first divided region 224, thereby guiding the projection light, whose intensity varies depending on the distance from the entrance region 210, to the emission region 230 while adjusting the distribution of the amount of light in the direction perpendicular to the traveling direction of the projection light to be approximately constant.

[0049] For example, the second grooves 222 are formed such that the depth of the second grooves 222 provided in one first dividing region 224 is greater than the depth of the second grooves 222 provided in a first dividing region 224 that is closer to the incident region 210 than the one first dividing region 224. In this case, the rate of change in the depth of the second grooves 222 between two adjacent first dividing regions 224 among the multiple first dividing regions 224 may be greater the farther away from the incident region 210.

[0050] 5, consider an intermediate region 220 having three first divided regions 224. Here, it is assumed that the depth of the second groove portion 222a in the first divided region 224a, which is the closest to the entrance region 210 among the three first divided regions 224, is formed so that approximately ¼ of the amount of the incident projection light is guided to the exit region 230. In this case, the remaining approximately ¾ of the amount of the projection light incident on the first divided region 224a, which is the closest to the entrance region 210, is incident on the adjacent first divided region 224b.

[0051] The depth of the second groove portion 222b of the first divided region 224b second closest to the entrance region 210 is formed so as to guide approximately 1 / 3 of the amount of incident projection light to the exit region 230. In other words, the depth of the second groove portion 222b of the first divided region 224b second closest to the entrance region 210 is formed greater than the depth of the second groove portion 222a so as to guide 4 / 3 times the amount of light compared to the first divided region 224a closest to the entrance region 210 to the exit region 230. Such a first divided region 224b guides approximately 1 / 4 of the amount of projection light incident on the first divided region 224a closest to the entrance region 210 to the exit region 230.

[0052] The remaining approximately half of the amount of the projection light incident on the first divided region 224a closest to the entrance region 210 is incident on the adjacent first divided region 224c. The depth of the second groove portion 222c of the first divided region 224c third closest to the entrance region 210 is formed so as to guide approximately half the amount of the incident projection light to the exit region 230. In other words, the depth of the second groove portion 222c of the first divided region 224c third closest to the entrance region 210 is formed greater than the depth of the second groove portion 222b so as to guide 3 / 2 times the amount of light to the exit region 230 compared to the first divided region 224b second closest to the entrance region 210.

[0053] Moreover, the rate of change in the depth of the second groove portion 222 of two adjacent first divided regions 224 out of the three first divided regions 224 is formed to increase with increasing distance from the entrance region 210. The first divided region 224c, which is the third closest to the entrance region 210, guides to the exit region 230 approximately ¼ of the amount of projection light incident on the first divided region 224a, which is the closest to the entrance region 210. As in the above example, it can be seen that the intermediate region 220 can guide the projection light to the exit region 230 while maintaining a substantially constant distribution of the amount of projection light guided to the exit region 230 corresponding to each first divided region 224 by varying the amount of projection light guided to the exit region 230 for each first divided region 224 to a predetermined value.

[0054] The intermediate region 220 may further include a first reflection region 226 at a position farthest from the incident region 210. Fig. 5 shows an example in which the intermediate region 220 includes three first divided regions 224 and the first reflection region 226. The first reflection region 226 reflects at least a portion of the light that has passed through the multiple first divided regions 224 back to the multiple first divided regions 224. The first reflection region 226 includes a second groove portion 222 having a depth greater than the depth of the second groove portion 222 of the adjacent first divided region 224.

[0055] Since the intermediate region 220 has such a first reflection region 226, the multiple first divided regions 224 guide at least a portion of the light reflected by the first reflection region 226 to the emission region 230. This allows the intermediate region 220 to guide a larger amount of projection light to the emission region 230. The depth of the second groove portion 222 of the multiple first divided regions 224 may be determined so that the amount of projection light that each first divided region 224 guides to the emission region 230, including the light reflected by the first reflection region 226, is approximately constant.

[0056] <Example of emission region 230> The emission region 230 guides at least a part of the projection light incident from the intermediate 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 the X-axis direction as the longitudinal direction on a surface approximately parallel to the XY plane, but is not limited to this. 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, a square, or a trapezoid with the Y-axis direction as the longitudinal direction.

[0057] 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.

[0058] The third period of the plurality of third grooves 232 provided in the emission region 230 is different from the second period of the plurality of second grooves 222 in the intermediate region 220. The third period of the plurality of third grooves 232 in the emission region 230 may be the same as the first period of the plurality of first grooves 212 in the incidence region 210. In this manner, by substantially matching the periods of the diffraction gratings provided in the region where the projection light is incident and the region where the image light is emitted, it is possible to reduce distortion and the like occurring in the image observed by the user. The third period is, for example, in the range of about 10 nm to about 10 μm.

[0059] The multiple third grooves 232 are arranged, for example, in a second direction from the intermediate region 220 toward the emission region 230. Fig. 5 shows an example in which the third grooves 232 extending in the first direction are arranged in the second direction.

[0060] Like the intermediate region 220, the emission region 230 has a plurality of second divided regions 234 arranged in the traveling direction of the projection light incident from the intermediate region 220. The third groove portions 232 formed in the plurality of second divided regions 234 have different depths. In other words, in the emission region 230, the third groove portions 232 are formed such that the proportion of light that is emitted as image light out of the input projection light differs for each second divided region 234.

[0061] It is desirable that the emission region 230 has two or more second divided regions 234. For example, the depth of the third groove portion 232 provided in one second divided region 234 is formed to be greater than the depth of the third groove portion 232 provided in a second divided region 234 closer to the intermediate region 220 than the one second divided region 234. Furthermore, when the emission region 230 has three or more second divided regions 234, the rate of change in the depth of the third groove portion 232 of two adjacent second divided regions 234 may be greater the farther away from the intermediate region 220.

[0062] As described above, 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, emission region 230, like the plurality of first divided regions 224 of intermediate region 220, can guide projection light as image light, while adjusting the distribution of the light amount of the entire image to be approximately constant when an observer observes the image light as an image.

[0063] The emission region 230 may further have a second reflection region 236 at a position farthest from the intermediate region 220. Fig. 5 shows an example in which the emission region 230 has two second divided regions 234 and the second reflection region 236. The second reflection region 236 reflects at least a part of the light that has passed through the multiple second divided regions 234 back to the multiple second divided regions 234. The second reflection region 236 has a third groove portion 232 with a depth greater than the depth of the third groove portion 232 of the adjacent second divided region 234.

[0064] Since the emission region 230 has such a second reflection region 236, the multiple second divided regions 234 emit at least a portion of the light reflected by the second reflection region 236 as image light from the second surface of the projection substrate 100. This allows the emission region 230 to emit more projection light as image light, similar to the intermediate region 220. Note that the depth of the third groove portion 232 of the multiple second divided regions 234 may be determined so as to make the amount of light emitted as image light by each second divided region 234, including the light reflected by the second reflection region 236, approximately constant.

[0065] As described above, the projection substrate 100 according to this embodiment branches the projection light incident on the entrance region 210 into different ratios for each of the multiple first divided regions 224 of the intermediate region 220, and emits the projection light as image light from the emission region 230. This allows the projection substrate 100 to reduce variation in brightness of the projected image observed by the user. Moreover, the projection substrate 100 also emits image light in different ratios for each of the multiple second divided regions 234 in the emission region 230, thereby further reducing variation in brightness of the image.

[0066] Such a projection substrate 100 can be realized by forming a diffraction grating corresponding to the entrance region 210, the intermediate 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, etc. Therefore, the projection substrate 100 according to this embodiment is a substrate that can be easily produced by forming grooves with a predetermined period and depth for each region, without incorporating a complex optical system.

[0067] <Second Configuration Example of Glasses-Type Terminal 10> In the above, an example of the glasses-type terminal 10 has been described in which one projection substrate 100 is provided on the frame 110 for each of the projection optical systems 50 for the right and left eyes, and the corresponding projection units 120 irradiate the projection light onto the incident areas 210 of the respective projection substrates 100, but the present invention is not limited to this. For example, one projection optical system 50 may be provided with a plurality of projection substrates 100. Such a glasses-type terminal 10 will be described next.

[0068] 6 shows a second configuration example of the glasses-type terminal 10 according to this embodiment. In the glasses-type terminal 10 of the second configuration example, parts that operate in substantially the same manner as the glasses-type terminal 10 according to this embodiment shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted. The appearance of the glasses-type terminal 10 of the second configuration example may be almost the same as that of the glasses-type terminal 10 shown in FIG. 1.

[0069] A plurality of projection substrates 100 are fixed to the frame 110 of the glasses-type terminal 10 of the second configuration example. In this case, the plurality of projection substrates 100 are fixed to the frame 110 such that the emission regions 230 provided on the respective projection substrates 100 at least partially overlap in a plan view substantially parallel to the XY plane. Fig. 6 shows an example in which three projection substrates 100R, 100G, and 100B are fixed to the frame 110 of the glasses-type terminal 10, and the emission regions 230R, 230G, and 230B of the three projection substrates 100 overlap in a plan view on the XY plane.

[0070] The projection unit 120 irradiates projection light of different wavelengths onto the entrance areas 210 provided on each of the projection substrates 100. As a result, the exit areas 230 provided on each of the projection substrates 100 emit image light corresponding to the projection light irradiated from the projection unit 120 onto each of the entrance areas 210 from the second surfaces of the projection substrates 100 to the user's eyes.

[0071] A user wearing such a glasses-type terminal 10 can observe an image in which image light of different wavelengths is superimposed, and can therefore observe an image having a mixed color. FIG. 6 shows an example in which the projection unit 120 irradiates three projection lights corresponding to the three primary colors of RGB, such as red, green, and blue, which form an image, onto the entrance areas 210 of three projection substrates 100, respectively. The three projection substrates 100 then superimpose the three image lights corresponding to the three primary colors of RGB and emit them to the user's eyes. This allows the user to see, for example, two n It is possible to observe an image having multiple colors of n=4, where n is a positive integer such as 4, 8, 16, 24, etc.

[0072] <Third Configuration Example of Glasses-Type Terminal 10> In the above-described glasses-type terminal 10, a part of the image light to be emitted toward the user may be emitted as leak light in a direction different from the user. For example, a part of the image light emitted from the second surface of the projection substrate 100 may be emitted from the first surface of the projection substrate 100 due to the diffraction grating of the optical waveguide section 200. In this case, a person looking at the user may feel uncomfortable because the user's eyes appear to be shining. Therefore, the glasses-type terminal 10 according to this embodiment may be configured to reduce such leak light. Such a configuration will be described next.

[0073] 7 shows a third configuration example of the glasses-type terminal 10 according to this embodiment. In the glasses-type terminal 10 of the third configuration example, the operations that are substantially the same as those of the glasses-type terminal 10 according to this embodiment shown in FIG. 1 are given the same reference numerals, and the explanations are omitted. Note that FIG. 7 is a diagram in which the projection unit 120 is omitted. The appearance of the glasses-type terminal 10 of the third configuration example may be almost the same as that of the glasses-type terminal 10 shown in FIG. 1.

[0074] In the glasses-type terminal 10 of the third configuration example, the projection optical system 50 further includes a polarization reduction plate 310. The polarization reduction plate 310 is provided on the first surface side of the projection substrate 100 with respect to the optical waveguide section 200 of the projection substrate 100 via an air layer. In this manner, the polarization reduction plate 310 is provided away from the optical waveguide section 200 so as not to affect the optical characteristics of the optical waveguide section 200.

[0075] The polarization reduction plate 310 covers at least a portion of the optical waveguide section 200, and reduces light in the polarization direction of the image light leaking from the first surface of the projection substrate 100. The polarization reduction plate 310 covers at least a portion of the output diffraction grating of the output region 230. This allows the polarization reduction plate 310 to receive the image light leaking from the output diffraction grating.

[0076] The image light leaking from the output diffraction grating is light that has been guided through the multiple diffraction gratings of the optical waveguide unit 200, and therefore becomes light polarized in one direction in accordance with the structure of the optical waveguide unit 200. Therefore, the polarization reduction plate 310 is provided so as to reduce the light in the polarization direction of the image light leaking from the first surface of the projection substrate.

[0077] As a result, the polarization reduction plate 310 can reduce the intensity of the leaked image light to a level below which the image light is not noticeable to others even when they see the user wearing the eyeglass-type terminal 10. In addition, the polarization reduction plate 310 transmits light having a polarization direction perpendicular to the polarization direction of the leaked image light, so that it can transmit external light and be visually recognized by the user.

[0078] FIG. 7 shows an example in which the polarization reduction plate 310 has a polarizing filter disposed opposite to the first surface of the projection substrate 100. The polarizing filter is a polarizing plate, a polarizing film, or the like that attenuates a linearly polarized component of the input light in a predetermined direction. The polarization reduction plate 310 is preferably fixed to the frame 110 or the projection substrate 100. Note that the polarization reduction plate 310 may be provided with a rotatable polarizing filter, and may be capable of adjusting the polarization direction (absorption axis) of the light to be reduced. The polarization reduction plate 310 may also be a polarizing film coated on a transparent substrate or the like. Such a polarization reduction plate 310 will be described next.

[0079] <Fourth Configuration Example of Glasses-Type Terminal 10> 8 shows a fourth configuration example of the glasses-type terminal 10 according to this embodiment. In the glasses-type terminal 10 of the fourth configuration example, the operations that are substantially the same as those of the glasses-type terminal 10 according to this embodiment shown in Figs. 1 and 7 are given the same reference numerals, and the explanations are omitted. The appearance of the glasses-type terminal 10 of the fourth configuration example may be almost the same as that of the glasses-type terminal 10 shown in Fig. 1.

[0080] In the glasses-type terminal 10 of the fourth configuration example, the polarization reduction plate 310 includes a protective substrate 320 and a polarizing film 330. The protective substrate 320 is provided opposite to the first surface of the projection substrate 100. The protective substrate 320 is a substrate that is transparent to at least visible light, such as a glass substrate or a plastic substrate.

[0081] The polarizing film 330 is coated on at least one of a third surface of the protective substrate 320 opposite to the projection substrate 100 and a fourth surface facing the projection substrate 100. FIG. 8 shows an example in which the polarizing film 330 is coated on the third surface of the protective substrate 320.

[0082] The polarizing film 330 is a thin film that attenuates the linearly polarized component of the input light in a predetermined direction, similar to a polarizing filter. The polarizing film 330 may be coated on a part or the whole of the protection substrate 320.

[0083] 7, the polarization reduction plate 310 having the protective substrate 320 and the polarizing film 330 can also reduce the intensity of image light leaked from the output diffraction grating and transmit external light for visual recognition by the user. The protective substrate 320 is preferably fixed to the frame 110 or the projection substrate 100. The protective substrate 320 may be rotatably provided and configured to adjust the direction of the absorption axis of the polarization reduction plate 310.

[0084] The glasses-type terminal 10 according to the present embodiment described above can reduce leakage of image light observed by a user with a simple configuration. Note that, in the glasses-type terminal 10, an example in which the transmission axis of the polarization reduction plate 310 is adjustable has been described, but the present invention is not limited to this. Alternatively or in addition to this, the glasses-type terminal 10 may be configured so that the polarization direction of the image light is adjustable.

[0085] For example, the projection unit 120 has a polarization adjustment unit that adjusts the polarization direction of the projection light irradiated to the entrance area 210. The polarization adjustment unit has, for example, a wavelength plate that rotates the polarization direction of linearly polarized light. The polarization adjustment unit adjusts the polarization direction of the image light leaking from the first surface of the projection substrate 100 so that it approximately matches the polarization direction in which the polarization reduction plate 310 reduces the light intensity. Such a projection unit 120 can adjust the polarization direction of the projection light so that the polarization reduction plate 310 appropriately reduces the leaked light while efficiently guiding the projection light in the optical waveguide unit 200.

[0086] The polarization adjustment unit may also adjust the polarization direction of the projection light so that the polarization direction of the image light leaking from the output diffraction grating becomes horizontal. In this case, the absorption axis of the polarization reduction plate 310 is made to substantially coincide with the horizontal direction. Then, the horizontal light of the light from the outside world is reduced by the polarization reduction plate 310. This allows the eyeglass-type terminal 10 to function as polarized glasses that reduce reflected light from horizontal surfaces such as the surface of water.

[0087] In the glasses-type terminal 10 of the third and fourth configuration examples described above, as explained in Fig. 6, the projection optical system 50 may include a plurality of projection substrates 100, and the user may observe an image in which a plurality of image lights of different wavelengths are superimposed. In this case, it is desirable that the polarization directions of the plurality of image lights are approximately the same.

[0088] The polarization reduction plate 310 is desirably provided on the side opposite the user of the multiple projection substrates 100. Fig. 6 shows an example in which the projection optical system 50 has three projection substrates 100 and one polarization reduction plate 310 provided on the side opposite the user of the three projection substrates 100.

[0089] Even in this case, the projection unit 120 may have a polarization adjustment unit that adjusts the polarization direction of at least one of the multiple projection lights irradiated to the incident area 210. The polarization adjustment unit adjusts the polarization direction of at least one of the multiple projection lights contained in the image light leaking from the first surface of the projection substrate 100 so that it approximately matches the polarization direction in which the polarization reduction plate 310 reduces the light intensity. This allows the projection unit 120 to efficiently guide at least one projection light in the optical waveguide unit 200, while adjusting the polarization direction of the projection light so that the polarization reduction plate 310 appropriately reduces the leaked light corresponding to the projection light.

[0090] The projection unit 120 may have a plurality of polarization adjustment units that adjust the polarization directions of the plurality of projection lights in response to the plurality of projection lights irradiated onto the entrance area 210. In this case, the projection unit 120 can adjust the polarization directions of the plurality of projection lights so that the polarization reduction plate 310 appropriately reduces leakage light corresponding to the plurality of projection lights while efficiently guiding the plurality of projection lights in the optical waveguide unit 200.

[0091] In the above-described eyeglass-type terminal 10 according to the present embodiment, an example has been described in which the optical waveguide section 200 of the projection substrate 100 has the entrance region 210, the intermediate region 220, and the exit region 230, but the present invention is not limited to this. The optical waveguide section 200 only needs to be able to output the projection light incident from the projection section 120 as image light for the user to observe, and the shapes of the entrance region 210, the intermediate region 220, and the exit region 230 may be other shapes. Furthermore, the optical waveguide section 200 may have, for example, the entrance region 210 and the exit region 230, but may not have the intermediate region 220.

[0092] Although the present invention has been described above using the embodiments, 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 distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0093] 10 Glasses-type terminal 20 input rays 30 Output ray flux 50 Projection optical system 100 Projection board 110 Frames 120 Projection section 200 Optical waveguide 210 Incidence area 212 First Groove 220 Intermediate area 222 Second groove 224 1st divided area 226 1st reflection area 230 Output area 232 Third Groove 234 Second divided area 236 2nd reflection area 310 Polarization reduction plate 320 Protection Board 330 Polarizing Film

Claims

1. A glasses-type terminal worn by a user, a projection substrate having an optical waveguide for transmitting at least a portion of light incident on a first surface to a second surface opposite the first surface and projecting image light onto the second surface; a polarization reduction plate that is provided on the first surface side of the projection substrate with respect to the optical waveguide portion via an air layer, covers at least a part of the optical waveguide portion, and reduces light in a polarization direction of the image light leaking from the first surface of the projection substrate; having The optical waveguide portion guides at least a part of the projection light for projecting the image light and emits the projection light from the second surface as the image light. A projection optical system; a frame for fixing the projection substrate; a projection unit provided on the frame and configured to irradiate an entrance area of ​​the optical waveguide unit of the projection substrate with the projection light for projecting the image light onto an exit area of ​​the optical waveguide unit; Equipped with the projection optical system is provided as at least one of a lens for a right eye and a lens for a left eye of the user, and projects the image light onto the second surface while transmitting at least a part of the light incident from the first surface to the eye of the user; the projection unit has a polarization adjustment unit that adjusts a polarization direction of the projection light that is irradiated onto the incident area, The polarization adjustment unit adjusts the polarization direction of the image light leaking from the first surface of the projection board so as to coincide with the polarization direction in which the polarization reduction plate reduces the intensity of light. Glasses-type device.

2. A glasses-type terminal worn by a user, a projection substrate having an optical waveguide for transmitting at least a portion of light incident on a first surface to a second surface opposite the first surface and projecting image light onto the second surface; a polarization reduction plate that is provided on the first surface side of the projection substrate with respect to the optical waveguide portion via an air layer, covers at least a part of the optical waveguide portion, and reduces light in a polarization direction of the image light leaking from the first surface of the projection substrate; having The optical waveguide portion guides at least a part of the projection light for projecting the image light and emits the projection light from the second surface as the image light. A projection optical system; a frame for fixing the projection substrate; a projection unit provided on the frame and configured to irradiate an entrance area of ​​the optical waveguide unit of the projection substrate with the projection light for projecting the image light onto an exit area of ​​the optical waveguide unit; Equipped with the projection optical system is provided as at least one of a lens for a right eye and a lens for a left eye of the user, and projects the image light onto the second surface while transmitting at least a part of the light incident from the first surface to the eye of the user; A plurality of the projection substrates are fixed to the frame, the polarization reduction plate is provided on a side of the projection substrate opposite to the user, the projection unit irradiates the projection light having a different wavelength onto the incidence area provided on each of the plurality of projection substrates; The emission regions provided on the plurality of projection substrates respectively at least partially overlap each other in a planar view, and the image light corresponding to the projection light irradiated from the projection unit onto the plurality of entrance regions is emitted from the second surfaces of the plurality of projection substrates respectively to the eyes of the user; the projection unit has a polarization adjustment unit that adjusts a polarization direction of at least one of the plurality of projection lights that are irradiated onto the incident area, The polarization adjustment unit adjusts the polarization direction of the image light corresponding to at least one of the projection lights whose polarization direction has been adjusted by the polarization adjustment unit among the plurality of image lights leaking from the first surfaces of the plurality of projection substrates so as to coincide with the polarization direction in which the polarization reduction plate reduces the light intensity. Glasses-type device.

3. The glasses-type terminal according to claim 1 , wherein the polarization reduction plate has a polarization filter provided opposite to the first surface of the projection substrate.

4. The polarization reduction plate is a protection substrate provided opposite the first surface of the projection substrate; a polarizing film coated on at least one of a third surface of the protective substrate opposite to the projection substrate and a fourth surface facing the projection substrate; The glasses-type terminal according to claim 1 , further comprising:

5. The optical waveguide portion is an incidence region having an incidence diffraction grating, into which the projection light for projecting the image light is incident and which guides the incident projection light into the inside of the projection substrate; an exit region having an exit diffraction grating, which guides at least a portion of the projection light incident from the entrance region and emits the light as the image light from the second surface; having The polarization reduction plate covers at least a portion of the exit diffraction grating. The glasses-type terminal according to claim 1 .

6. the optical waveguide unit further includes an intermediate region including an intermediate diffraction grating and configured to guide a portion of the projection light incident from the entrance region toward the exit region; the incident diffraction grating has a plurality of first grooves formed at a first period; the intermediate diffraction grating has a plurality of second groove portions formed at a second period; the output diffraction grating has a plurality of third groove portions formed at a third period; The eyeglass-type terminal according to claim 5 .

Images