Projection substrate and glasses-type terminal

Abstract

A projection substrate includes: an incident region on which projection light is incident and which has a diffraction grating that guides at least a portion of the incident projection light in a first direction and a second direction within the projection substrate; a first branch region having a diffraction grating that guides at least a portion of the incident projection light in a third direction; a second branch region having a diffraction grating that guides at least a portion of the incident projection light in a fourth direction; and an emission region on which the projection light guided by the first branch region and the second branch region is incident, the emission region having a diffraction grating that emits at least a portion of the incident projection light as image light.

Description

Technical Field

[0001] This invention relates to a projection substrate and an eyeglasses-type terminal. Background Technology

[0002] Previously, there were known devices such as eyeglasses and head-mounted displays that used optical systems including waveguides to display two-dimensional images for users to view (see, for example, Patent Document 1 and Patent Document 2). In addition, there were known two-dimensional diffraction gratings that diffract light in two directions (see, for example, Patent Document 3).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-207686

[0006] Patent Document 2: International Publication No. 2023 / 047488

[0007] Patent Document 3: US Patent No. 8160411 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Because such devices require the optical system to be housed within a limited space, the optical system becomes complex, which can sometimes lead to higher manufacturing costs.

[0010] Therefore, the present invention is made in view of these aspects, and its object is to reduce the manufacturing cost of the projection substrate for users to view projected images.

[0011] Technical means to solve the problem

[0012] In a first embodiment of the present invention, a projection substrate is provided for transmitting at least a portion of light incident from a first surface to a second surface opposite to the first surface, and projecting image light onto the second surface. The projection substrate includes: an incident region for the projection light for projecting the image light to be incident, and having a diffraction grating that guides at least a portion of the incident projection light toward a first direction within the projection substrate and a second direction different from the first direction; and a first branch region disposed relative to the incident region in the first direction, for the projection light guided in the incident region to be incident, and having a diffraction grating that guides at least a portion of the incident projection light toward a second direction different from the first direction. A third-party guided waveguide in different directions; a second branch region, positioned relative to the incident region in the second direction, for the projection light guided by the waveguide in the incident region to be incident, and having a diffraction grating that directs at least a portion of the incident projection light toward a fourth-direction guided waveguide in a direction different from the second direction; and an exit region, positioned relative to the first branch region in the third direction and positioned relative to the second branch region in the fourth direction, for the projection light guided by the waveguide in the first branch region and the second branch region to be incident respectively, and having a diffraction grating that directs at least a portion of the incident projection light out from the second surface as the image light.

[0013] Alternatively, the incident region may have: a first diffraction grating for light from the projection light incident on the incident region that is to be emitted toward the first branch region; and a second diffraction grating disposed at a different position from the first diffraction grating for light from the projection light incident on the incident region that is to be emitted toward the second branch region.

[0014] Alternatively, the incident region may have a two-dimensional diffraction grating that guides at least a portion of the incident projection light to the first branch region and guides at least a portion of the remaining light of the incident projection light to the second branch region.

[0015] Alternatively, the incident region may have multiple diffraction gratings or two-dimensional diffraction gratings with different periods, guiding the first wavelength of the projected light to the first branch region, and guiding the second wavelength of the projected light, which is different from the first wavelength, to the second branch region.

[0016] Alternatively, the incident region may guide the light waves with red and green wavelengths in the projected light to the first branch region, and guide the light waves with green and blue wavelengths in the projected light to the second branch region.

[0017] Alternatively, the incident region may have multiple diffraction gratings or two-dimensional diffraction gratings with the same period, and the wavelength of the projected light to be guided to the first branch region may be set to the same wavelength as the wavelength of the projected light to be guided to the second branch region.

[0018] Alternatively, the first branch region may guide at least a portion of the projected light incident from the incident region to a region of the exiting region that includes the specified region, and the second branch region may guide at least a portion of the projected light incident from the incident region to a region of the exiting region that does not include the specified region.

[0019] Alternatively, the first branch region may guide at least a portion of the projected light incident from the incident region to a region of the exiting region that includes the specified region, and the second branch region may guide at least a portion of the projected light incident from the incident region to a region of the exiting region that includes the specified region.

[0020] Alternatively, the emission region may have a two-dimensional diffraction grating, which emits at least a portion of the projection light incident from the first branch region and at least a portion of the projection light incident from the second branch region from the second surface as the image light.

[0021] In a second embodiment of the present invention, an eyeglass-type terminal is provided for a user to wear. The eyeglass-type terminal includes: a projection substrate according to the first embodiment, which is provided as at least one of the user's right eye lens and left eye lens, so that at least a portion of light incident from the first surface is transmitted to the user's eye and the image light is projected onto the second surface; a frame for fixing the projection substrate; and a projection unit disposed in the frame for irradiating the incident area of ​​the projection substrate with the projection light used to project the image light onto the exit area.

[0022] The effects of the invention

[0023] According to the present invention, the manufacturing cost of the projection substrate for users to view projected images is reduced. Attached Figure Description

[0024] Figure 1 This section illustrates a structural example of the glasses-type terminal 10 in this embodiment.

[0025] Figure 2 This represents a general outline of the optical path of the projected light in the eyeglass-type terminal 10 of this embodiment.

[0026] Figure 3This represents a general outline of the optical path of the projection light in the existing projection substrate S.

[0027] Figure 4 This represents an example of existing projection light L and image light P.

[0028] Figure 5 This illustrates a structural example of a glasses-type terminal D that incorporates multiple layers of an existing projection substrate S.

[0029] Figure 6 This represents a general outline of the optical path of the projection light in the projection substrate 100 of this embodiment.

[0030] Figure 7 This section illustrates a structural example of the projection substrate 100 in this embodiment.

[0031] Figure 8 This illustrates a structural example of a glasses-type terminal 10 that combines the projection substrate 100 of this embodiment with a conventional projection substrate S in a multilayer configuration.

[0032] Figure 9 This section illustrates a structural example of an eyeglass-type terminal 10 with a projection substrate 100 multilayered according to this embodiment. Detailed Implementation

[0033] <Structural Example of Eyeglasses Terminal 10>

[0034] Figure 1 This section illustrates a structural example of the glasses-type terminal 10 according to this embodiment. In this embodiment, three mutually orthogonal axes are designated as the X-axis, Y-axis, and Z-axis. The glasses-type terminal 10 is a device worn by a user, such as a wearable device. The glasses-type terminal 10 allows the user to view the scenery through glasses and projects image light onto a display area provided on the projection substrate 100. The glasses-type terminal 10 includes a projection substrate 100, a frame 110, and a projection unit 120.

[0035] The projection substrate 100 transmits at least a portion of the light incident from the first surface to the user's eye and projects image light onto the second surface. Here, the first surface of the projection substrate 100 is the side facing the user when the user is wearing the glasses-type terminal 10. The second surface of the projection substrate 100 is the side facing the user when the user is wearing the glasses-type terminal 10. Figure 1 This illustrates an example where the first and second surfaces of the projection substrate 100 are arranged substantially parallel to the XY plane. The projection substrate 100 is, for example, a glass substrate on which a diffraction grating, functioning as a waveguide, is formed. The projection substrate 100 will be described later.

[0036] The frame 110 fixes the projection substrate 100. The projection substrate 100 is provided in the frame 110 as at least one of the user's right eye lens and left eye lens. Figure 1The following example illustrates that a projection substrate 100a is provided in the frame 110 as a lens for the user's right eye, and a projection substrate 100b is provided as a lens for the left eye.

[0037] Alternatively, the frame 110 may be provided with a projection substrate 100 to serve as a lens for the user's right or left eye. Furthermore, the frame 110 may also be provided with a projection substrate 100 to serve as lenses for both eyes. In this case, the frame 110 may also have the shape of goggles. The frame 110 has sections such as a temple and a strap to allow the user to wear the glasses-type terminal 10.

[0038] A projection unit 120 is disposed in the frame 110 and illuminates the projection substrate 100 with projection light for projecting image light onto the projection substrate 100. One or more such projection units 120 are disposed in the frame 110. Figure 1 The following example illustrates that the frame 110 is provided with a projection section 120a for irradiating projection light L1 onto the projection substrate 100a and a projection section 120b for irradiating projection light L2 onto the projection substrate 100b.

[0039] The projection unit 120 can be disposed at the location where the projection substrate 100 is fixed in the frame 110, or at the side support of the frame 110, etc. Ideally, the projection unit 120 is disposed integrally with the frame 110. For example, the projection unit 120 illuminates the projection substrate 100 with projection light containing one wavelength to allow the user to view a monochrome image. Moreover, the projection unit 120 can also illuminate the projection substrate 100 with projection light containing multiple wavelengths to allow the user to view an image containing multiple colors.

[0040] Figure 2 This diagram illustrates the general optical path of the projection light in the eyeglass-type terminal 10 of this embodiment. The projection unit 120 illuminates the projection light into the incident region 210 provided on the projection substrate 100. The incident region 210 guides the projection light into the substrate of the projection substrate 100. Furthermore, the projection substrate 100 emits the projection light guided within the substrate from the exit region 230 as image light. The incident region 210 and the exit region 230 will be described later.

[0041] <Optical path of existing projection substrate S>

[0042] Figure 3This represents a schematic representation of the optical path of the projection light in a conventional projection substrate S. The projection substrate S has an incident region 210, a branching region 220, and an exiting region 230. The projection light L is incident on the incident region 210 and exits from the exiting region 230 as image light P after passing through the branching region 220. As the projection light L travels away from the incident region 210, the branching region 220 guides the projection light L portion by portion to the exiting region 230.

[0043] Similarly, the exit region 230 also travels away from the branch region 220 as the projection light L moves away, and emits portions of the projection light L as part of the image light P. Thus, the projection substrate S emits the projection light L incident on the incident region 210 from the exit region 230 as the image light P.

[0044] <An example of existing projection light L and image light P>

[0045] Figure 4 This describes an example of projection light L emanating from an existing projection unit 120 onto an existing projection substrate S, and image light P emitted from the existing projection substrate S. For example, the projection unit 120 irradiates projection light L towards a second surface of the projection substrate S located in the +Z direction. The projection light L corresponds to an image seen by the user. For example, if a screen is provided on a surface substantially parallel to the XY plane to project the projection light L, an image M1 is displayed on that screen for the user to view. The image seen by 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. Thus, the projection unit 120 irradiates multiple rays forming the image M1 on a surface substantially parallel to the XY plane as projection light L.

[0046] In this embodiment, the following example will be described: the projection unit 120 projects an image M1, which is approximately rectangular with the X-axis as its long side, onto a plane that is approximately parallel to the XY plane. Furthermore, Figure 4 In this design, five of the multiple light rays emitted by the projection unit 120 are designated as input rays 20. For example, the ray corresponding to the top left pixel of the image is designated as the first input ray 20a, the ray corresponding to the bottom left pixel of the image is designated as the second input ray 20b, the ray corresponding to the center pixel of the image is designated as the third input ray 20c, the ray corresponding to the top right pixel of the image is designated as the fourth input ray 20d, and the ray corresponding to the bottom right pixel of the image is designated as the fifth input ray 20e.

[0047] The projection unit 120, for example, illuminates the projection light L onto the incident area 210 of the projection substrate S to form an upright virtual image at infinity or a predetermined position. The projection light incident on the incident area 210 passes through the branching area 220 and exits as image light P from the exiting area 230. The image light P exits from the exiting area 230 and enters the eye of a user separated from the projection substrate S by a distance d. Furthermore, the image light P is imaged onto the retina of the user's eye as image M2. Thus, the image light P comprises multiple light beams that are imaged as image M2.

[0048] Figure 4 In this diagram, five of the multiple light beams that illuminate the circular region C of the emission region 230 of the projection substrate S and image it at a predetermined position are designated as output light beams 30. For example, the light beam that images the lower right pixel of the image is designated as the first output light beam 30a, the light beam that images the upper right pixel of the image is designated as the second output light beam 30b, the light beam that images the center pixel of the image is designated as the third output light beam 30c, the light beam that images the lower left pixel of the image is designated as the fourth output light beam 30d, and the light beam that images the upper left pixel of the image is designated as the fifth output light beam 30e.

[0049] Each light beam corresponds to a plurality of 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, which includes a plurality of light beams generated by multiple branching and multiple diffractions from the incident region 210 to the exit region 230 of the projection substrate S. 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.

[0050] In other words, the image M2 formed on the retina of the user's eye by the image light P emitted from the emission area 230 corresponds to the image M1 projected by the projection light L irradiated by the projection unit 120. Thus, the user wearing the glasses-type terminal 10 can perceive that the image M2 is superimposed on the scenery seen through the projection substrate S and projected onto the second surface of the projection substrate S. In other words, the emission area 230 functions as a display area for displaying the image M2 corresponding to the image M1 projected by the projection light L.

[0051] Figure 4 In this context, the image M2 observed by the user is an example of an image M1 projected by the projection light L, which is inverted both vertically and horizontally. Furthermore, the image M1 projected by the projection light L can be a static image, or alternatively, a dynamic image.

[0052] In the projection substrate S, the emitting region 230 emits image light P with uniform light intensity throughout, allowing a user wearing the glasses-type terminal 10 to see a natural image M2 with uniform light intensity throughout the image. At this time, sufficient light must be supplied to the emitting region 230 as a whole, based on widening the angle of view of the light that can be guided by the incident region 210 and the branch region 220. Furthermore, in order for the user to view the image M2 with uniform light intensity from multiple wavelengths, such as a full-color image, the incident region 210 and the branch region 220 must widen the angle of view that can be guided for multiple wavelengths of light, and supply light to the emitting region 230 as a whole.

[0053] The angle of view of the light guided by the incident region 210 and the branch region 220 can be increased by increasing the refractive index of the projection substrate S. However, since the refractive index of the projection substrate S is determined by materials such as glass, plastic, and resin, its magnitude is limited. Conventionally, by multiplying the projection substrate S, the area of ​​the exit region 230 can be increased, or image light P containing multiple wavelengths can be emitted. Therefore, an example of multiplying the projection substrate S will be described below.

[0054] <Eyeglass-type terminal D with multi-layered projection substrate S>

[0055] Figure 5 This illustrates a structural example of a glasses-type terminal D that incorporates multiple layers of an existing projection substrate S. Figure 5 In the eyeglass-type terminal D shown, for the... Figure 2 The same symbols are used for devices with similar operation to the glasses-type terminal 10 shown, and descriptions are omitted. The appearance of the glasses-type terminal D may be similar to... Figure 1 The appearance of the glasses-type terminal 10 shown is almost unchanged.

[0056] Multiple projection substrates S are fixed to the frame 110 of the eyeglass-type terminal D. At this time, the multiple projection substrates S are fixed to the frame 110 in such a way that the emission areas 230 of the multiple projection substrates S are respectively set in a way that at least part of them overlap when viewed from above and are approximately parallel to the XY plane. Figure 5 The following example is shown, in which three projection substrates SR, SG and SB are fixed on the frame 110 of the eyeglass terminal D, and the emission regions 230R, 230G and 230B of the three projection substrates S overlap when viewed from above in the XY plane.

[0057] The projection unit 120 illuminates the incident areas 210, which are respectively provided on the plurality of projection substrates S, with projection light of different wavelengths. As a result, the image light corresponding to the projection light that is respectively illuminated by the projection unit 120 to the incident areas 210, which are respectively provided on the plurality of projection substrates S, is emitted from the second surface of the plurality of projection substrates S to the user's eye.

[0058] Users wearing this type of glasses terminal D will see an image composed of superimposed light of different wavelengths, thus allowing them to view images with mixed colors. Figure 5 The following example illustrates that the projection unit 120 illuminates the incident areas 210 of the three projection substrates S with three projection lights corresponding to the three primary colors of RGB (red, green, and blue) used to form an image. Furthermore, the three projection substrates S overlap with the three image lights corresponding to the three primary colors of RGB and emit them towards the user's eye. Thus, the user can, for example, view an image with 2... n Images of multiple colors. Here, n is a positive integer such as 4, 8, 16, 24 (equivalent to a full-color image), etc.

[0059] also, Figure 5 The example shown illustrates a glasses-type terminal D with three projection substrates S, but the number of projection substrates S is not limited to three. The glasses-type terminal D includes two projection substrates S, one of which guides red and green projected light, and the other guides blue projected light. In this case, one of the two projection substrates S guides red projected light, and the other guides green and blue projected light. Additionally, one of the two projection substrates S guides a portion of the red and green frequency bands of projected light, and the other guides the remaining green frequency band and blue projected light.

[0060] Alternatively, in the glasses-type terminal D, the multiple projection substrates S are fixed to the frame 110 in such a way that at least a portion of the emission areas 230 of the multiple projection substrates S do not overlap when viewed from above, which is approximately parallel to the XY plane. Thus, when the user sees the image light emitted from the multiple projection substrates S, they can view an image with a wider area than a single emission area 230.

[0061] As described above, by multiplying the projection substrate S, the area of ​​the image that the user can view can be increased, or the image colors can be made multi-colored. However, multiplying the projection substrate S increases the manufacturing cost of the glasses-type terminal D. Therefore, although the projection substrate 100 of this embodiment is a single-layer substrate, it can increase the area of ​​the image that the user can view, or make the image colors multi-colored with fewer layers. First, the optical path of this projection substrate 100 will be described.

[0062] <Optical path of projection substrate 100>

[0063] Figure 6This diagram illustrates the general optical path of the projection light in the projection substrate 100 of this embodiment. The projection substrate 100 has an incident region 210, a first branch region 221, a second branch region 222, and an exit region 230. A portion of the projection light L is incident on the incident region 210 and exits as image light P from the exit region 230 after passing through the first branch region 221. Additionally, at least a portion of the remaining light from the projection light L is incident on the incident region 210 and exits as image light P from the exit region 230 after passing through the second branch region 222.

[0064] As described above, the projection substrate 100 emits the projection light L incident on the incident region 210 as image light P from the exit region 230 via two paths. This projection substrate 100 will now be described.

[0065] <Structure Example of Projection Substrate 100>

[0066] Figure 7 This section illustrates a structural example of the projection substrate 100 in this embodiment. Figure 7 This illustrates an example where the first and second surfaces of the projection substrate 100 are arranged substantially parallel to the XY plane. The projection substrate 100 is a substrate for transmitting at least a portion of light incident from the first surface to a second surface opposite the first surface, and projecting image light onto the second surface. The projection substrate 100 is a substrate formed of glass, plastic, resin, or the like. The projection substrate 100 includes an incident region 210, a first branch region 221, a second branch region 222, and an exit region 230.

[0067] Incident region 210 is provided for the incident projection light used to project the image. Incident region 210 may be formed on a first surface of projection substrate 100, or alternatively, on a second surface of projection substrate 100. Incident region 210 has a diffraction grating that guides at least a portion of the incident projection light toward a first direction within projection substrate 100 and a second direction different from the first direction. Here, the first direction is the direction in which the first branch region 221 is provided, and the second direction is the direction in which the second branch region 222 is provided. In other words, incident region 210 guides at least a portion of the incident projection light to the first branch region 221 and the second branch region 222. Furthermore, the first and second directions may be orthogonal, or alternatively, not orthogonal.

[0068] The incident region 210, for example, has a first diffraction grating 211 and a second diffraction grating 212. The first diffraction grating 211 has a plurality of grooves formed at a first period for light from the projection light incident on the incident region 210 that is to exit toward the first branch region 221. The plurality of grooves are arranged in the same direction on the upper surface of the projection substrate 100 with a predetermined groove width and spacing, thereby functioning as a diffraction grating. The first diffraction grating 211 can be a reflective diffraction grating or a transmissive diffraction grating.

[0069] The first period of the multiple grooves is, for example, in the range of approximately 10 nm to approximately 10 μm. Preferably, the first period is in the range of approximately 100 nm to approximately 1 μm. More preferably, the first period is in the range of approximately 200 nm to approximately 800 nm. The depth of the multiple grooves is in the range of approximately 1 nm to approximately 10 μm. Preferably, the depth of the multiple grooves is in the range of approximately 10 nm to approximately 250 nm. More preferably, the depth of the multiple grooves is in the range of approximately 50 nm to approximately 250 nm.

[0070] The fill factor of the multiple slots ranges from approximately 0.05 to approximately 0.95. Preferably, the fill factor of the multiple slots ranges from approximately 0.3 to approximately 0.7. Here, the fill factor is the value obtained by dividing the distance between two adjacent slots by the first period. Furthermore, sometimes the distance between two adjacent slots is referred to as a line, the width of the slot as a space, and the first period as the spacing. In this case, the spacing is the sum of the line and the space, and the fill factor is the value obtained by dividing the line by the spacing.

[0071] Multiple slots are arranged, for example, in a direction from the incident region 210 toward the first branch region 221. The projection light is focused and incident on the incident region 210, so that the incident region 210 guides the projection light to the first branch region 221 in such a way that the first direction is centered in the plane of the projection substrate 100 and has a diffusion angle.

[0072] The second diffraction grating 212 has multiple grooves formed in a second period to allow light from the projection light incident on the incident region 210 that is to exit towards the second branch region 222 to be incident. The second diffraction grating 212 is located at a different position than the first diffraction grating 211. The multiple grooves of the second diffraction grating 212 function as diffraction gratings in the same way as the multiple grooves of the first diffraction grating 211. The second diffraction grating 212 can be a reflective diffraction grating or a transmissive diffraction grating. The first diffraction grating 211 and the second diffraction grating 212 can be formed integrally or separately.

[0073] The second period of the plurality of grooves is formed within the same range as the first period. The second period may be the same as the first period, or it may be a different period than the first period. In addition, the depth and fill factor of the plurality of grooves of the second diffraction grating 212 are also formed within the same range as the depth and fill factor of the plurality of grooves of the first diffraction grating 211.

[0074] The plurality of grooves of the second diffraction grating 212 are arranged, for example, in a direction from the incident region 210 toward the second branch region 222. The incident region 210 guides the projection light wave to the second branch region 222 in such a way that it has a diffusion angle centered on the second direction in the plane of the projection substrate 100.

[0075] As described above, the incident region 210 has a first diffraction grating 211 that guides the wave to the first branch region 221 and a second diffraction grating 212 that guides the wave to the second branch region 222, guiding the incident projection light to the first direction and the second direction. In this case, the projection unit 120 is configured to illuminate the first diffraction grating 211 of the incident region 210 with the projection light to be guided to the first branch region 221, and to illuminate the second diffraction grating 212 of the incident region 210 with the projection light to be guided to the second branch region 222.

[0076] A first branch region 221 is positioned relative to the incident region 210 in a first direction, allowing projection light guided in the incident region 210 to be incident. The first branch region 221 may be formed on a first surface of the projection substrate 100, or alternatively, on a second surface of the projection substrate 100. The first branch region 221 has a diffraction grating that guides at least a portion of the incident projection light towards a third direction, different from the first direction. Here, the third direction is the direction in which the exit region 230 is located. In other words, the first branch region 221 guides at least a portion of the incident projection light to the exit region 230. Furthermore, the first direction and the third direction may be orthogonal, or alternatively, not orthogonal.

[0077] The first branch region 221 has a reflective diffraction grating that guides the projection light toward the direction of the exit region 230 through reflective diffraction. The first branch region 221 may, for example, have a rectangular shape with the first direction set as the long side direction. The first branch region 221 may also have a trapezoidal, fan-shaped, or other shapes corresponding to the region where the projection light diffuses and travels in the XY plane.

[0078] The first branch region 221 has a diffraction grating with multiple grooves formed in a third period. Ideally, the third period should be appropriately selected to guide the projected light to the emission region 230. For example, the third period is in the range of approximately 10 nm to approximately 10 μm. Preferably, the third period is in the range of approximately 50 nm to 1 μm. More preferably, the third period is in the range of approximately 100 nm to 700 nm.

[0079] The depth of the multiple grooves ranges from approximately 1 nm to approximately 10 μm. Preferably, the depth of the multiple grooves ranges from approximately 10 nm to approximately 250 nm. More preferably, the depth of the multiple grooves ranges from approximately 10 nm to approximately 100 nm. The fill factor of the multiple grooves ranges from approximately 0.05 to approximately 0.95. Preferably, the fill factor of the multiple grooves ranges from approximately 0.2 to approximately 0.85.

[0080] The plurality of slots in the first branch region 221 are arranged, for example, in a predetermined direction. For instance, when the angle between the first direction and the second direction is defined as the first angle, the plurality of slots are formed in a direction inclined at half the first angle relative to the first direction toward a third direction. As an example, when the first direction is approximately parallel to the X-axis, and the second and third directions are approximately parallel to the Y-axis, the first angle is approximately 90 degrees, and the plurality of slots are arranged in a direction inclined at approximately 45 degrees relative to the first direction toward a third direction. Needless to say, alternatively, the period and the first angle of the first branch region 221 can be achieved through various combinations.

[0081] The second branch region 222 is positioned relative to the incident region 210 in a second direction, allowing projection light guided in the incident region 210 to be incident. The first branch region 221 may be formed on a first surface of the projection substrate 100, or alternatively, on a second surface of the projection substrate 100. The second branch region 222 has a diffraction grating that guides at least a portion of the incident projection light toward a fourth direction, which is different from the second direction. Here, the fourth direction is the direction in which the exit region 230 is located. In other words, the second branch region 222 guides at least a portion of the incident projection light to the exit region 230. Furthermore, the second and fourth directions may be orthogonal, or alternatively, not orthogonal.

[0082] Like the first branch region 221, the second branch region 222 has a reflective diffraction grating, which guides the projection light to the direction of the exit region 230 through reflective diffraction. The second branch region 222 may, for example, have a rectangular shape with the second direction set as the long side direction. The second branch region 222 may also have a trapezoidal, fan-shaped, or other shapes corresponding to the region where the projection light diffuses and travels in the XY plane.

[0083] The second branch region 222 has a diffraction grating with a plurality of grooves formed in a fourth period. Ideally, the fourth period should be appropriately selected to guide the projected light to the exit region 230. The fourth period is formed within the same range as the third period. Furthermore, the depth and fill factor of the plurality of grooves in the second branch region 222 are preferably formed within the same range as the depth and fill factor of the plurality of grooves in the first branch region 221.

[0084] The multiple slots of the second branch region 222 are arranged, for example, in a predetermined direction. For instance, when the angle between the first and second directions is defined as the first angle, the multiple slots are formed in a direction inclined at half the first angle relative to the second direction toward the fourth direction. As an example, when the first and fourth directions are approximately parallel to the X-axis, and the second direction is approximately parallel to the Y-axis, the first angle is approximately 90 degrees, and the multiple slots are arranged in a direction inclined at approximately 45 degrees relative to the second direction toward the fourth direction. Needless to say, alternatively, the period of the second branch region 222 and the first angle can be achieved through various combinations.

[0085] The emission region 230 is positioned in a third direction relative to the first branch region 221 and in a fourth direction relative to the second branch region 222, allowing projection light guided by waveguides in the first branch region 221 and the second branch region 222 to be incident on them respectively. The emission region 230 may be formed on a first surface of the projection substrate 100, or alternatively, on a second surface of the projection substrate 100. The emission region 230 has a diffraction grating that emanates at least a portion of the incident projection light from the second surface of the projection substrate 100 as image light.

[0086] Figure 7 This example illustrates that the emission region 230 has a rectangular shape with the X-axis direction as the longer side on a surface approximately parallel to the XY plane, but it is not limited to this. The emission region 230 can be used to guide the projection light and emit it as an image light, for example, it can have a rectangular, trapezoidal, oblong, or elliptical shape with the Y-axis direction as the longer side, or it can have a square or circular shape instead.

[0087] The exit region 230 has a reflective or transmissive diffraction grating that guides the image light toward the user's eye through reflective or transmissive diffraction. The exit region 230 also has a two-dimensional diffraction grating that emits at least a portion of the projection light incident from the first branch region 221 and at least a portion of the projection light incident from the second branch region 222 from the second surface of the projection substrate 100 as image light.

[0088] A two-dimensional diffraction grating has multiple slots formed in a third and a fourth direction, for example. The multiple slots in the third direction are formed with a predetermined slot width and spacing, and function as a third diffraction grating from which the projection light incident from the first branch region 221 exits as image light. Similarly, the multiple slots in the fourth direction are formed with a predetermined slot width and spacing, and function as a fourth diffraction grating from which the projection light incident from the second branch region 222 exits as image light. More specific structures of the two-dimensional diffraction grating are described in, for example, Patent Document 3, etc., and therefore are omitted here.

[0089] The emission region 230 is not limited to the above description as long as it can emit at least a portion of the projection light incident from the first branch region 221 and at least a portion of the projection light incident from the second branch region 222 from the second surface of the projection substrate 100 as image light. For example, the emission region 230 may be formed on both the first and second surfaces of the projection substrate 100.

[0090] At this time, the first emission region formed on the first surface of the projection substrate 100 emits one of the projection lights, namely the projection light incident from the first branch region 221 and the projection light incident from the second branch region 222, as image light from the second surface of the projection substrate 100. As an example, the first emission region has a plurality of grooves formed in the third direction.

[0091] Furthermore, the second emission region formed on the second surface of the projection substrate 100 emits a different projection light, different from the projection light emitted from the first emission region, from both the projection light incident from the first branch region 221 and the projection light incident from the second branch region 222. As an example, the second emission region has multiple grooves formed in the fourth direction. Thus, the emission region 230, constructed from a combination of one-dimensional diffraction gratings formed on the first and second surfaces of the projection substrate 100, can have the same function as a two-dimensional diffraction grating.

[0092] The fifth period of the plurality of grooves formed on the third upward side of the exit region 230 may be a different period from the third period of the plurality of grooves in the first branch region 221. Alternatively, the fifth period may be the same as the first period of the first diffraction grating 211 in the incident region 210.

[0093] Similarly, the sixth period of the plurality of grooves formed in the fourth direction of the emission region 230 can be a different period from the fourth period of the plurality of grooves in the second branch region 222. Alternatively, the sixth period can be the same as the second period of the second diffraction grating 212 in the incident region 210. Thus, by aligning the period of the diffraction grating provided in the region where the projected light is incident with the region where the emitted image light is emitted, distortions in the image viewed by the user can be reduced.

[0094] The fifth and sixth periods are formed within the same range as the first period of the first diffraction grating 211 in the incident region 210. The fifth period may be the same as the sixth period, or it may be a different period. Furthermore, the depths of the plurality of grooves formed in the third and fourth directions of the exit region 230 are in the range of approximately 1 nm to approximately 10 μm. The depths of the plurality of grooves in the third and fourth directions are preferably in the range of approximately 10 nm to approximately 250 nm. More preferably, the depths of the plurality of grooves are in the range of approximately 10 nm to approximately 100 nm. The depths of the plurality of grooves in the third direction may be the same as the depths of the plurality of grooves in the fourth direction, or they may be different depths.

[0095] The fill factor of the multiple slots in the third and fourth directions is in the range of approximately 0.05 to approximately 0.95. The fill factor of the multiple slots in the third and fourth directions is preferably in the range of approximately 0.2 to approximately 0.85. The fill factor of the multiple slots in the third direction may be the same as that of the multiple slots in the fourth direction, or it may be a different value.

[0096] The above-described exit region 230 is configured, for example, such that, within a predetermined region, the projection light incident from the first branch region 221 overlaps with the projection light incident from the second branch region 222. In this case, the first branch region 221 guides at least a portion of the projection light incident from the incident region 210 to the region of the exit region 230 containing the predetermined region, and the second branch region 222 guides at least a portion of the projection light incident from the incident region 210 to the region of the exit region 230 containing the predetermined region.

[0097] Therefore, the emission region 230 can combine and emit light guided by the first branch region 221 and the light guided by the second branch region 222 within a specified area. In other words, compared with the existing projection substrate S that uses a single-path guided projection light, the emission region 230 can emit more projection light as image light from the specified area.

[0098] Furthermore, the exit region 230 may be configured such that, in at least a portion of its area, the projection light incident from the first branch region 221 does not overlap with at least a portion of the projection light incident from the second branch region 222. In this case, the first branch region 221 guides at least a portion of the projection light incident from the incident region 210 to a region of the exit region 230 that includes the predetermined region, and the second branch region 222 guides at least a portion of the projection light incident from the incident region 210 to a region of the exit region 230 that does not include the predetermined region.

[0099] Therefore, while the emission region 230 emits the projection light from the first branch region 221 guided wave from a predetermined area as image light, it can also emit the projection light from the second branch region 222 guided wave from a region different from the predetermined area as image light. In other words, compared with the existing projection substrate S using a single-path guided wave projection light, the emission region 230 allows for a wider area that can be emitted as image light.

[0100] Furthermore, the projection substrate 100 is configured such that, while projection light from the first branch region 221 is emitted as image light from the first region of the emission region 230, projection light from the second branch region 222 is emitted as image light from a second region of the emission region 230 that is different from the first region. In this case, the first and second regions of the emission region 230 can be conventional one-dimensional diffraction gratings. Alternatively, if the emission region 230 is formed by the first and second regions, the emission region 230 may not include a two-dimensional diffraction grating.

[0101] As described above, the projection substrate 100 of this embodiment uses two paths for the projection light incident on the incident region 210: one via a waveguide in the first branch region 221 to the exit region 230, and the other via a waveguide in the second branch region 222 to the exit region 230. The projection light is then emitted from the exit region 230 as image light. Therefore, the projection substrate 100 can use the projection light from two existing projection substrate S-waveguides on a single substrate waveguide. As a result, since the projection substrate 100 of this embodiment reduces the number of substrates provided on the eyeglasses-type terminal 10, manufacturing costs can be reduced. Furthermore, the weight of the eyeglasses-type terminal 10 can be reduced.

[0102] For example, the incident region 210 has a first diffraction grating 211 and a second diffraction grating 212 with different periods, guiding a first wavelength of the projected light to a first branch region 221, and guiding a second wavelength of the projected light (different from the first wavelength) to a second branch region 222. The first branch region 221, for example, has a diffraction grating corresponding to the first wavelength, guiding the first wavelength of light to a predetermined area of ​​the exit region 230. Furthermore, the second branch region 222 has a diffraction grating corresponding to the second wavelength, guiding the second wavelength of light to a predetermined area of ​​the exit region 230. In this case, the exit region 230 has two-dimensional diffraction gratings corresponding to both the first and second wavelengths in the predetermined area.

[0103] Therefore, the projection substrate 100 does not use the two-layer structure of the existing projection substrate S which combines light of the first wavelength and light of the second wavelength, but can guide light of the first wavelength and light of the second wavelength through a single substrate and emit it as image light from a predetermined area. In addition, the projection substrate 100 can also guide light of the first band containing light of the first wavelength and light of the second band containing light of the second wavelength.

[0104] For example, incident region 210 guides the light with red and green wavelengths in the projected light to the first branch region 221, and guides the light with green and blue wavelengths in the projected light to the second branch region 222. At this time, the path guided from the first branch region 221 to the exit region 230 can guide light in the green band that is close to the red wavelength, and the path guided from the second branch region 222 to the exit region 230 can guide light in the green band that is close to the remaining blue wavelength.

[0105] The first branch region 221, for example, has a diffraction grating corresponding to the red and green bands, guiding the red and green light waves to a predetermined area of ​​the output region 230. The second branch region 222 may have a diffraction grating corresponding to the green and blue bands, guiding the green and blue light waves to a predetermined area of ​​the output region 230. In this case, the output region 230 has a two-dimensional diffraction grating corresponding to the red and green bands and the green and blue bands in the predetermined area.

[0106] Therefore, the projection substrate 100 does not use the two-layer structure of the existing projection substrate S which combines guided red and green light and the existing projection substrate S which guides green and blue light, but can guide red, green and blue light from a single substrate and emit it as image light from a designated area. In other words, the projection substrate 100 can emit full-color image light, white image light, etc. from the emission area 230 at low cost.

[0107] Furthermore, needless to say, the combination of frequency ranges guided by the paths via the first branch region 221 to the emission region 230 and via the second branch region 222 to the emission region 230 can also be other combinations. For example, the path via the first branch region 221 to the emission region 230 can guide red and green projected light, while the path via the second branch region 222 to the emission region 230 can guide blue projected light. Additionally, the path via the first branch region 221 to the emission region 230 can guide red projected light, while the path via the second branch region 222 to the emission region 230 can guide green and blue projected light.

[0108] Alternatively, the incident region 210 can have multiple diffraction gratings with the same period, and the wavelength of the projected light guided to the first branch region 221 can be set to the same wavelength as the wavelength of the projected light guided to the second branch region 222. In this case, the frequency ranges of the waves guided through the first branch region 221 to the exit region 230 and the paths guided through the second branch region 222 to the exit region 230 become the same frequency range.

[0109] For example, the projection substrate 100 is configured such that, in a predetermined area of ​​the exit region 230, the projection light incident from the first branch region 221 overlaps with the projection light incident from the second branch region 222. At this time, the projection unit 120 supplies the same projection light to the first diffraction grating 211 and the second diffraction grating 212 of the incident region 210. Thus, the projection substrate 100 outputs the same image light from the exit region 230 via two paths.

[0110] Therefore, even if one of the two paths is defective or has debris, the user can correctly view the image light as long as the other path is normal. Thus, by using light of the same wavelength in both paths, the projection substrate 100 can improve manufacturing yield and reduce manufacturing costs.

[0111] Furthermore, for example, the projection substrate 100 is configured such that, in a defined area of ​​the emission region 230, at least a portion of the projection light incident from the first branch region 221 and the projection light incident from the second branch region 222 do not overlap. In this case, as described above, the projection substrate 100 can use an emission region 230 with a larger area than that of a conventional projection substrate S that emits image light via a single path, thereby reducing manufacturing costs and enabling users to view large-screen images.

[0112] This projection substrate 100 can be realized by forming a diffraction grating corresponding to the incident region 210, the branch region 220, and the exit region 230 on a first or second surface of a glass substrate or the like. Furthermore, the grooves forming the diffraction grating can be, for example, a photoresist or resin. Therefore, the projection substrate 100 of this embodiment is a substrate that can be easily manufactured by forming grooves of a predetermined period and depth in each region without the need for a complex optical system.

[0113] <Structural Example of Multi-Layer Glasses-Type Terminal 10>

[0114] Furthermore, the above-mentioned glasses-type terminal 10 can be constructed by combining multiple such projection substrates 100. Alternatively, the projection substrate 100 of this embodiment can be combined with a conventional projection substrate S. Figure 8 This illustrates a structural example of a glasses-type terminal 10 that combines the projection substrate 100 of this embodiment with a conventional projection substrate S in a multilayer configuration.

[0115] In the projection substrate 100, green projection light is guided along a path from the first branch region 221 to a predetermined area of ​​the emission region 230, and blue projection light is guided along a path from the second branch region 222 to the predetermined area of ​​the emission region 230. Furthermore, the projection substrate 100 guides red projection light to the predetermined area of ​​the emission region 230. Thus, with... Figure 5 Compared to the existing glasses-type terminal D described herein, the glasses-type terminal 10 can reduce the number of substrates by one.

[0116] Figure 9 This section illustrates a structural example of an eyeglass-type terminal 10 with a projection substrate 100 multilayered according to this embodiment. Figure 9 This example illustrates that the glasses-type terminal 10 includes a first projection substrate 100R, a second projection substrate 100G, and a third projection substrate 100B, totaling three substrates.

[0117] In the first projection substrate 100R, red projection light is guided along a path from the first branch region 221 to the first region of the emission region 230, and red projection light is guided along a path from the second branch region 222 to the second region of the emission region 230. In the second projection substrate 100G, green projection light is guided along a path from the first branch region 221 to the first region of the emission region 230, and green projection light is guided along a path from the second branch region 222 to the second region of the emission region 230.

[0118] In the third projection substrate 100B, blue projection light is guided along a path from the first branch region 221 to the first region of the emission region 230, and blue projection light is guided along a path from the second branch region 222 to the second region of the emission region 230. Thus, with... Figure 5 Compared to the existing glasses-type terminal D described herein, the glasses-type terminal 10 can double the area of ​​the emission region 230 without changing the number of substrates.

[0119] In the projection substrate 100 of this embodiment described above, an example was given in which the incident region 210 has two portions (a first diffraction grating 211 and a second diffraction grating 212) for the incident light to be incident, but this is not a limitation. The incident region 210 may, for example, have a two-dimensional diffraction grating. The two-dimensional diffraction grating guides at least a portion of the incident projection light to the first branch region 221 and guides at least a portion of the remaining light of the incident projection light to the second branch region 222.

[0120] At this time, the projection unit 120 overlaps the projection light guided by the first branch region 221 with the projection light guided by the second branch region 222, and illuminates the two-dimensional diffraction grating of the incident region 210. This allows for a reduction in the area of ​​the incident region 210. Furthermore, when the incident region 210 has a two-dimensional diffraction grating, it is ideal that the first direction and the second direction are orthogonal.

[0121] In the projection substrate 100 of this embodiment described above, an example was described in which the first branch region 221 and the second branch region 222 guide the incident projection light toward the waveguide of the emission region 230. In addition, the first branch region 221 and the second branch region 222 have multiple segmented regions with different diffraction efficiencies, and the intensity of the light guiding the wave toward the emission region 230 can be adjusted according to the distance from the incident region 210.

[0122] Thus, the first branch region 221 can guide the projected light, which makes the light intensity uniform in the first direction, to the exit region 230, and the second branch region 222 can guide the projected light, which makes the light intensity uniform in the second direction, to the exit region 230. Furthermore, at the ends of the first branch region 221 and the second branch region 222 opposite to the incident region 210, there may be reflecting regions that reflect the light guided by the projected light. These reflecting regions reflect light leaking out from the ends of the first branch region 221 and the second branch region 222 opposite to the incident region 210 back to the branch regions, thereby enabling the light to be guided to the exit region 230 without waste.

[0123] Furthermore, the emission region 230 has segmented regions, and the intensity of the emitted image light can be adjusted according to the position of the emission region 230 to make the overall image light intensity of the emission region 230 uniform. Additionally, the emission region 230 may have reflection regions at the ends opposite to the first branch region 221 and opposite to the second branch region 222. Since the segmented regions and reflection regions are described in Patent Document 2, etc., detailed descriptions are omitted here.

[0124] 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 embodiments, and various modifications and alterations can be made within its scope. For example, all or part of the device can be functionally or physically distributed / integrated in any unit. Moreover, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of new embodiments resulting from combinations also include the effects of the original embodiments.

[0125] Explanation of icon numbers

[0126] 10: Glasses-type terminal

[0127] 100: Projection substrate

[0128] 110: Framework

[0129] 120: Projection Department

[0130] 210: Incident area

[0131] 211: First diffraction grating

[0132] 212: Second diffraction grating

[0133] 220: Branch Region

[0134] 221: First branch region

[0135] 222: Second branch region

[0136] 230: Launch Zone

Claims

1. A projection substrate for transmitting at least a portion of light incident from a first surface to a second surface opposite to the first surface, and projecting image light onto the second surface, the projection substrate comprising: An incident region is provided for the projection light to be projected onto the image light, and has a diffraction grating that directs at least a portion of the incident projection light toward a first direction within the projection substrate and as a second direction waveguide, which is different from the first direction. A first branch region is located at a position relative to the incident region in the first direction, for the projection light that has been guided in the incident region to be incident, and has a diffraction grating that directs at least a portion of the incident projection light toward a third-party guide wave that is in a direction different from the first direction. The second branch region is located at a position relative to the incident region in the second direction, for the projection light that is guided by the waveguide in the incident region to be incident, and has a diffraction grating that directs at least a portion of the incident projection light toward a fourth direction waveguide that is different from the second direction. as well as The emission region is located in the third direction relative to the first branch region and in the fourth direction relative to the second branch region, for the projection light guided by the waveguide in the first branch region and the second branch region to be incident on respectively, and has a diffraction grating that emits at least a portion of the incident projection light from the second surface as the image light.

2. The projection substrate according to claim 1, wherein... The incident region has: A first diffraction grating is provided for the incident light from the projected light destined to exit the first branch region; and A second diffraction grating is positioned at a different location from the first diffraction grating, allowing light from the projected light incident on the incident region that is to be emitted toward the second branch region to be incident.

3. The projection substrate according to claim 1, wherein... The incident region has a two-dimensional diffraction grating that guides at least a portion of the incident projection light to the first branch region and guides at least a portion of the remaining light of the incident projection light to the second branch region.

4. The projection substrate according to claim 1, wherein The incident region contains multiple diffraction gratings or two-dimensional diffraction gratings with different periods, guiding the first wavelength of the projected light to the first branch region, and guiding the second wavelength of the projected light, which is different from the first wavelength, to the second branch region.

5. The projection substrate according to claim 4, wherein... The incident region guides the light waves with red and green wavelengths in the projected light to the first branch region, and guides the light waves with green and blue wavelengths in the projected light to the second branch region.

6. The projection substrate according to claim 1, wherein... The incident region has multiple diffraction gratings or two-dimensional diffraction gratings with the same period, and the wavelength of the projected light to be guided to the first branch region is set to the same wavelength as the wavelength of the projected light to be guided to the second branch region.

7. The projection substrate according to claim 1, wherein... The first branch region guides at least a portion of the projected light incident from the incident region to a region comprising a defined area in the exit region. The second branch region guides at least a portion of the projected light incident from the incident region to a region of the exit region that does not include the specified region.

8. The projection substrate according to claim 1, wherein The first branch region guides at least a portion of the projected light incident from the incident region to a region comprising a defined area in the exit region. The second branch region guides at least a portion of the projected light incident from the incident region to the region of the exit region that includes the designated region.

9. The projection substrate according to claim 1, wherein The emission region has a two-dimensional diffraction grating, which emits at least a portion of the projection light incident from the first branch region and at least a portion of the projection light incident from the second branch region from the second surface as the image light.

10. A glasses-type terminal for a user to wear, the glasses-type terminal comprising: The projection substrate as described in any one of claims 1 to 9 is provided as at least one of the user's right eye lens and left eye lens, so that at least a portion of the light incident from the first surface is transmitted to the user's eye, and the image light is projected onto the second surface; A frame is used to fix the projection substrate; as well as A projection unit is disposed in the frame, which illuminates the incident area of ​​the projection substrate with the projection light used to project the image light onto the exit area.

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