Light guide device, optical module and head-mounted display equipment

Abstract

The embodiment of the invention provides a light guide device, an optical module and head-mounted display equipment. The light guide device comprises a light guide substrate, a coupling-in area and a coupling-out area, wherein the coupling-in area and the coupling-out area are arranged on the light guide substrate. The coupling-out area is used for performing pupil expansion and coupling-out on the light from the coupling-in area; the coupling-out area comprises at least one first strip-shaped grating with grooves, the number of the grooves is at least two, the grooves are formed in the two opposite sides of the first strip-shaped grating respectively, and the grooves can be used for increasing the diffraction order of the first strip-shaped grating and forming target diffraction efficiency corresponding to the diffraction order. Therefore, light transmitted to the position of the first strip-shaped grating can be converted from original single-side diffraction of the first strip-shaped grating to additional diffraction of the light on the other side of the first strip-shaped grating. According to the scheme provided by the embodiment of the invention, the light energy can be reasonably distributed in the coupling-out region, and the lighting effect and the imaging quality can be improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical imaging technology. More specifically, the embodiments of the present application relate to a light guide device, an optical module and a head-mounted display device. Background Art

[0002] In the existing diffraction waveguide solution, a coupling-in region and a coupling-out region are respectively arranged on the waveguide plate. At present, the structure of all gratings in the coupling-out region is consistent, so the diffraction efficiency of the coupled-out light at different positions in the coupling-out region is consistent. Since the total energy of the light is constant, as the light is transmitted, the energy of the light at the edge and tail positions in the coupling-out region will become lower and lower, and the energy of the coupled-out light will also become lower and lower, resulting in uneven image intensity and low overall optical efficiency. Summary of the invention

[0003] The purpose of this application is to provide a new technical solution for a light-guiding device, an optical module and a head-mounted display device, so as to achieve different diffraction efficiencies in different areas within the outcoupling zone.

[0004] In a first aspect, the present application provides a light guide device. The light guide device comprises a light guide substrate and an incoupling region and an outcoupling region arranged on the light guide substrate;

[0005] The outcoupling region is used to expand the pupil of the light from the incoupling region and couple it out;

[0006] The outcoupling region includes at least one first strip grating with grooves, and the grooves are arranged in at least two and are arranged on opposite sides of the first strip grating. The grooves can be used to increase the diffraction order of the first strip grating and form a target diffraction efficiency corresponding to the diffraction order, so that the light propagating to the position of the first strip grating can be transformed from the original single-side diffraction on the first strip grating to the other side of the first strip grating.

[0007] Optionally, the outcoupling region includes a plurality of mutually independent sub-outcoupling regions;

[0008] A plurality of the first stripe gratings are provided and are located in at least one of the sub-outcoupling regions to form a transition grating region between the two-dimensional grating region and the one-dimensional grating region.

[0009] Optionally, in one of the sub-coupling regions, the first strip grating is arranged in plurality;

[0010] The plurality of first strip gratings are adjacent and spaced apart to form a partitioned arrangement in the sub-coupling area; or the plurality of first strip gratings are adjacent and sequentially connected to form a whole in the sub-coupling area.

[0011] Optionally, the width of the first strip grating is L, and the groove depth of the groove is ≤L;

[0012] When the groove depth of the groove is L, the groove penetrates the first strip grating in the width direction of the first strip grating, so that the diffraction efficiency of the increased diffraction order on the other side of the first strip grating reaches a maximum value.

[0013] Optionally, the groove includes a groove bottom and a groove wall extending from the groove bottom;

[0014] The groove wall comprises a first surface and a second surface opposite to each other, the first surface and the groove bottom form a first angle A1, the second surface and the groove bottom form a second angle A2, the first angle A1 and the second angle A2 are 0° to 180;

[0015] The angle between the groove bottom and the side of the first strip grating along the length direction is 0° to 89°;

[0016] The sizes of the first surface and the second surface along the width direction of the first stripe grating are 0 to 1000 nm.

[0017] Optionally, the plurality of sub-outcoupling regions include a two-dimensional grating region and a one-dimensional grating region;

[0018] Wherein, the two-dimensional grating region is located in the middle of the outcoupling region;

[0019] The one-dimensional grating region is provided with at least two and is disposed at two opposite sides of the two-dimensional grating region; the transition grating region is located between the two-dimensional grating region and the one-dimensional grating region.

[0020] Optionally, the two-dimensional grating region includes a plurality of parallelogram gratings, and the plurality of parallelogram gratings are arranged to form a first target shape;

[0021] The one-dimensional grating region includes a plurality of second strip gratings, and the second strip gratings do not have the grooves, and the plurality of second strip gratings are arranged to form a second target shape.

[0022] Optionally, the outcoupling region is provided on a surface of the light-guiding substrate;

[0023] In the outcoupling region: two opposite sides of the grating structure form an angle with the surface of the light-guiding substrate, and the angle is 20° to 160°; or the grating structure is a step grating

[0024] In a second aspect, the present application provides an optical module. The optical module comprises:

[0025] The light guide device according to the first aspect; and

[0026] An optical machine is used to project light or an image into the light guiding device.

[0027] In a third aspect, the present application provides a head mounted display device. The head mounted display device comprises:

[0028] a housing; and

[0029] An optical module as described in the second aspect.

[0030] The beneficial effects of this application are:

[0031] According to the light-guiding device provided in the embodiment of the present application, which is a diffraction light waveguide solution, a strip grating with grooves is introduced in the out-coupling zone, and the opposite sides of the strip grating are respectively provided with grooves. The introduction of the grooves increases the diffraction order of the strip grating, and the original one-dimensional grating characteristics of the strip grating can be broken, forming a transitional grating structure between a two-dimensional grating and a one-dimensional grating. When it is used in the out-coupling zone, it is beneficial to reasonably distribute the light energy in the out-coupling zone, and the final imaging picture quality is good and the optical efficiency is high.

[0032] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0034] Figure 1 One of the top views of the light guide device provided in the embodiment of the present application;

[0035] Figure 2 A second top view of the light guide device provided in an embodiment of the present application;

[0036] Figure 3 A top view of the outcoupling zone design of the light guide device provided in an embodiment of the present application;

[0037] Figure 4 The pupil expansion effect diagram of setting two-dimensional gratings in all out-coupling areas without partitioning;

[0038] Figure 5 A schematic diagram of the structure of a first strip grating provided in an embodiment of the present application;

[0039] Figure 6 Another structural schematic diagram of the first strip grating provided in an embodiment of the present application;

[0040] Figure 7A schematic diagram of another structure of the first strip grating provided in an embodiment of the present application;

[0041] Figure 8 A schematic diagram of another structure of the first strip grating provided in an embodiment of the present application;

[0042] Fig. 9 One of the structural schematic diagrams of the groove provided in the embodiment of the present application;

[0043] Fig.10 The second structural schematic diagram of the groove provided in the embodiment of the present application;

[0044] Fig.11 A schematic diagram of the structure of a groove provided in an embodiment of the present application;

[0045] Fig.12 Another schematic diagram of the structure of the groove provided in the embodiment of the present application;

[0046] Fig.13 Another structural schematic diagram of the groove provided in the embodiment of the present application

[0047] Fig.14 A side view of a light guide device provided in an embodiment of the present application.

[0048] Description of reference numerals:

[0049] 1. Light-guiding substrate; 2. Coupling-in region; 3. Coupling-out region; 31. First strip grating; 311. Side; 301. Two-dimensional grating region; 302. One-dimensional grating region; 303. Transition grating region; 4. Groove; 41. Groove bottom; 42. First surface; 43. Second surface; 01. First light ray; 02. Second light ray; 03. Third light ray; 1001. First diffracted light ray; 1002. Second diffracted light ray; 1003. First outcoupled light ray; 1004. Third diffracted light ray; 1005. Second outcoupled light ray. DETAILED DESCRIPTION

[0050] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0051] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0052] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0053] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0054] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0055] The light guide device, optical module and head-mounted display device provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0056] According to one aspect of an embodiment of the present application, a light guide device is provided, wherein the light guide device is, for example, a diffraction light waveguide solution, which can be suitable for application in a wearable device. The wearable device includes a head mounted display (HMD), such as an AR head mounted display device.

[0057] The specific form of the head-mounted display device includes, for example, smart glasses or a smart helmet, etc. The specific form of the head-mounted display device is not limited in the embodiments of the present application.

[0058] According to one embodiment of the present application, a light guide device is provided. Figure 1 and Figure 2 The light guide device comprises a light guide substrate 1 and an incoupling area 2 and an outcoupling area 3 arranged on the light guide substrate 1. The outcoupling area 3 is used to expand the pupil of the light from the incoupling area 2 and outcouple it; the outcoupling area 3 comprises at least one first strip grating 31 with grooves 4, and the grooves 4 are provided in at least two numbers and are arranged on opposite sides of the first strip grating 31, and the grooves 4 can be used to increase the diffraction order of the first strip grating 31 and form a target diffraction efficiency corresponding to the diffraction order, so that the light propagating to the position of the first strip grating 31 can be transformed from the original single-side diffraction on the first strip grating 31 to the diffraction on the other side of the first strip grating 31.

[0059] According to the above embodiment of the present application, the light guide device is, for example, a diffraction light waveguide solution, which can be applied to the field of augmented reality technology, etc. Among them, a coupling grating is arranged in the coupling-in area 2, and the coupling-in grating can be, for example, a hologram or a photonic crystal, etc., which can be used to couple external light, such as light projected by an optical machine, into the light guide substrate 1, and enable the coupled light to be fully reflected in the light guide substrate 1 and propagate to the coupling-out area 3. The coupling-out area 3 has the function of expanding the pupil and coupling out light.

[0060] The decoupling region 3 is designed to have at least one first strip grating 31 with a groove 4. The appearance of the first strip grating 31 can be seen in FIG. Figure 1 and Figure 2 By introducing grooves on opposite sides of the strip grating, the original one-dimensional grating characteristics of the strip grating can be broken, so that after the light enters the strip grating with grooves, it can be diffracted on both sides of the strip grating.

[0061] It should be noted that, for the first strip grating 31, the diffraction efficiency of the newly added diffraction order is related to the arrangement of the grooves 4 on the first strip grating 31 and / or the shape of the grooves 4 themselves. Among them, the shape of the grooves 4 is mainly affected by the groove depth and groove width. The diffraction efficiency of the newly added diffraction order may be different from the diffraction efficiency of the original diffraction order. For example, the diffraction efficiency of the newly added diffraction order is less than the diffraction efficiency of the original diffraction order.

[0062] According to the light-guiding device provided in the embodiment of the present application, the outcoupling region 3 may be designed in a partitioned manner, and a first strip grating 31 with a groove 4 is arranged in at least one sub-region. The diffraction performance of the first strip grating 31 is between that of a two-dimensional grating and that of a one-dimensional grating, see Figures 1 to 3 , a transition grating between a two-dimensional grating and a one-dimensional grating is formed in the outcoupling area 3. The application of the transition grating in the outcoupling area 3 can make the outcoupling area 3 form a more reasonable and fine partition, and the light after pupil expansion forms a more reasonable light energy distribution in the outcoupling area 3, which is conducive to improving the imaging quality.

[0063] For example, see Figure 1 and Figure 2 , the first light 01 from the coupling-in area 2 propagates to the coupling-out area 3 in the state of total reflection in the light-guiding substrate 1, and the first light 01 undergoes diffraction behavior at the position of the first strip grating 31, and forms the second light 02 according to the original diffraction order of the first strip grating 31, and the first strip grating 31 has a groove 4, so a third light 03 is added. As for the third light 03, it is directly related to the groove 4 on the first strip grating 31. The shape of the groove 4 and the layout on the first strip grating 31 can be designed in advance as needed to adjust the diffraction efficiency of the newly added diffraction order. This is conducive to a more reasonable adjustment of the diffraction behavior of the pupil expansion light in the coupling-out area 3, conducive to the reasonable distribution of light energy, and can also improve the light efficiency.

[0064] See also Figure 4 , Figure 4 The optical behavior of an unpartitioned outcoupling region 3 which is designed as a two-dimensional grating is shown. Figure 4The coupling-in zone 2 is used to receive the light projected by the external optical machine, and couple the light into the light-guiding substrate to generate the first diffraction light 1001 that propagates toward the coupling-out zone 3, i.e., the two-dimensional grating direction. When the first diffraction light 1001 is incident on the coupling-out zone 3, it will propagate the second diffraction light 1002 to both sides, and the first coupling-out light 1003 will continue to propagate along the original direction. When the second diffraction light 1002 is incident on the coupling-out zone 3 again, the third diffraction light 1004 and the second coupling-out light 1005 will be generated, wherein the diffraction direction of the third diffraction light 1004 is the same as that of the first diffraction light 1001, and the second diffraction light 1002 will continue to propagate along the original direction. When the first diffraction light 1001 and the third diffraction light 1004 and other light rays are incident on the coupling-out zone 3, coupled diffraction light is generated and continues to propagate forward. Due to Figure 4 All grating structures in the outcoupling area 3 shown have the same shape, so the efficiency of the first outcoupling light 1003, the second outcoupling light 1005 and other identical light outcoupling behaviors are consistent. The inability to adjust the light energy distribution in the outcoupling area may result in the light energy not being truly and effectively utilized, which will reduce the optical efficiency.

[0065] The light-guiding device provided in the embodiment of the present application improves the decoupling zone 3 by introducing a first strip grating 31 with a groove 4 in the decoupling zone 3. This design strengthens the diffraction order of the strip grating, so that the strip grating is transformed from being able to diffract light only on one side to being able to diffract light on both sides, and the diffraction efficiencies on both sides are different, thus forming a transition grating between a two-dimensional grating and a one-dimensional grating, thereby achieving the effect of reasonably distributing light in the decoupling zone 3.

[0066] According to the light-guiding device provided in the embodiment of the present application, which is a diffraction light waveguide solution, at least one first strip grating 31 with grooves 4 is introduced into the out-coupling zone 3, and the first strip grating 31 has one or more grooves 4 on opposite sides. The introduction of the grooves 4 increases the diffraction order of the first strip grating 31, which can break the original one-dimensional grating characteristics of the strip grating, and form a transition grating structure between a two-dimensional grating and a one-dimensional grating. When it is used in the out-coupling zone 3, it is beneficial to reasonably distribute the light energy in the out-coupling zone 3, and the final imaging picture quality is good and the optical efficiency is high.

[0067] It should be emphasized that the traditional strip grating exhibits the characteristics of a one-dimensional grating, but after at least one groove 4 is set on it, the characteristics of the original one-dimensional grating can be broken, so that the first strip grating 31 provided with the groove 4 can have a diffraction order in another direction, so that the light can be diffracted in two different directions. This optical behavior can enhance the light energy in another direction.

[0068] In the light guide device provided in the embodiment of the present application, the coupling-in region 2 and the coupling-out region 3 may be located on the same surface of the light guide substrate 1, or may be separately arranged on two opposite surfaces of the light guide substrate 1. In other words, the coupling-in region 2 and the coupling-out region may be placed on the upper surface or the lower surface of the light guide substrate in any arrangement and combination, and no limitation is imposed on this in the present application.

[0069] The light-guiding device provided in the embodiment of the present application is, for example, a diffraction optical waveguide, and the diffraction grating in the coupling-in region 2 and the diffraction grating in the coupling-out region 3 may form a closed grating vector polygon. The coupling-in region 2 may be composed of a single one-dimensional or two-dimensional grating or a plurality of one-dimensional or two-dimensional gratings. The coupling-out region 3 may be composed of a single two-dimensional grating or a plurality of one-dimensional or two-dimensional gratings.

[0070] The direction of the one-dimensional grating vector is perpendicular to its grating line, which is the direction of its periodic change, and its length is equal to the reciprocal of the grating period. The two-dimensional grating is periodically distributed in both horizontal and vertical directions.

[0071] In some examples of this application, see Figure 3 The outcoupling region 3 includes a plurality of mutually independent sub-outcoupling regions; a plurality of the first strip gratings 31 are provided and are located in at least one of the sub-outcoupling regions to form a transition grating region 303 between the two-dimensional grating region and the one-dimensional grating region.

[0072] According to the above example, the decoupling zone 3 is a partitioned design, which may include multiple sub-decoupling zones, and these sub-decoupling zones may be the same or different. For the multiple sub-decoupling zones, at least one sub-decoupling zone introduces a certain number of first strip gratings 31 with grooves 4, and the diffraction performance of the sub-decoupling zone is between the two-dimensional grating zone and the one-dimensional grating zone. In this way, in the decoupling zone 3, the light energy can be more reasonably distributed after pupil expansion, which can improve the optical efficiency of the entire light-guiding device.

[0073] When the groove 4 is arranged on the first strip grating 31, the diffraction efficiency ratio of the newly added diffraction order on the other side of the first strip grating 31 can be designed by designing the groove depth and / or groove width of the groove 4, thereby achieving the purpose of rationally utilizing light energy.

[0074] According to the above example, in the outcoupling region 3, one or more sub-outcoupling regions including the first strip grating 31 may be provided, and this is not limited in the embodiment of the present application.

[0075] In some examples of the present application, in one sub-coupling region, the first strip grating 31 is provided in plurality; wherein, see Figure 1, the plurality of first strip gratings 31 are adjacent and spaced apart to form a partition arrangement in the sub-coupling area; or, see Figure 2 The plurality of first strip gratings 31 are adjacent and sequentially connected to form a whole in the sub-coupling region.

[0076] For example, see Figure 1 On the middle right side, a sub-coupling area in the outcoupling area 3 is shown, in which three first strip gratings 31 can be arranged, for example, and intervals are arranged between adjacent first strip gratings 31, that is, each of the first strip gratings 31 is independent, and each of the first strip gratings 31 is respectively provided with a plurality of grooves 4 on opposite sides along the length direction.

[0077] For example, see Figure 2 On the middle right side, a sub-coupling area in the outcoupling area 3 is shown, in which three first strip gratings 31 are arranged, and adjacent first strip gratings 31 are connected to each other. Each of the first strip gratings 31 is respectively provided with a plurality of grooves 4 on opposite sides along the length direction, and finally all the first strip gratings 31 in the sub-coupling area form a diamond appearance.

[0078] In some examples of the present application, the width of the first strip grating 31 is L, and the groove depth of the groove 4 is ≤L; when the groove depth of the groove 4 is L, the groove 4 penetrates the first strip grating 31 in the width direction of the first strip grating 31, so that the diffraction efficiency of the increased diffraction order on the other side of the first strip grating 31 reaches the maximum value.

[0079] The greater the groove depth of the groove 4, the higher the diffraction efficiency of the newly added diffraction order on the other side of the first strip grating 31 provided with the groove 4. When the groove 4 completely penetrates the width direction of the first strip grating 31, the diffraction efficiency of the newly added diffraction order of the first strip grating 31 reaches a maximum value.

[0080] It should be noted that when the groove depth of the groove 4 is 0, that is, no groove is formed on the first strip grating 31, the first strip grating 31 maintains the diffraction characteristics of a one-dimensional grating.

[0081] Wherein, in the case where a plurality of grooves 4 are provided on the first strip grating 31, the plurality of grooves 4 are designed to be arranged at intervals along the length direction of the first strip grating 31, and the plurality of grooves 4 are arranged on opposite sides of the strip grating 31, see Figures 5 to 7 .

[0082] The grooves 4 on both sides of the first strip grating 31 can be symmetrically arranged, and the symmetry includes axial symmetry and central symmetry. Of course, the grooves 4 on both sides of the first strip grating 31 can also be asymmetrically arranged. This allows a higher degree of freedom in the design of the formed transition grating region.

[0083] Optionally, for the first strip grating 31 with the groove 4, a groove may be further formed in the groove 4, see Figure 6 and Figure 7 , which provides more ways to adjust the diffraction efficiency.

[0084] In addition, see Figure 8 In the case where a plurality of grooves 4 are provided on the strip grating 31 , the plurality of grooves 4 are arranged at intervals along the length direction of the first strip grating 31 , and the plurality of grooves 4 may also be located on the same side of the first strip grating 31 .

[0085] In some examples of this application, see Fig. 9 The groove 4 includes a groove bottom 41 and a groove wall extending from the groove bottom 41; wherein, see Fig.10 The groove wall includes a first surface 42 and a second surface 43 opposite to each other, the first surface 42 and the groove bottom 41 form a first angle A1, the second surface 43 and the groove bottom 41 form a second angle A2, the first angle A1 and the second angle A2 are 0° to 180; the angle between the groove bottom 41 and the side 311 of the first strip grating 31 along the length direction is 0° to 89°.

[0086] See also Fig.10 The size of the first surface 42 and the second surface 43 along the width direction of the first strip grating 31 is 0 to 1000 nm.

[0087] For example, see Fig.11 , shows a shape of the groove 4, wherein the first angle A1 is 120°, the second angle A2 is 60°, and the angle between the groove bottom 41 and the side 311 of the first strip grating 31 along the length direction is 0°.

[0088] For example, see Fig.12 , shows another shape of the groove 4, wherein the first angle A1 is 60°, the second angle A2 is 90°, and the angle between the groove bottom 41 and the side 311 of the first strip grating 31 along the length direction is 0°.

[0089] For another example, see Fig.13, shows another shape of the groove 4, wherein the first surface 42 is parallel to the second surface 43, and the angle between the groove bottom 324 and the side 311 of the first strip grating 31 along the length direction is 30°.

[0090] It should be emphasized that the arrangement of the grooves 4 is mainly to increase the diffraction order of the strip grating. Grooves of different shapes and numbers will affect the diffraction efficiency of the newly added diffraction order of the strip grating.

[0091] In one example of this application, see Figure 3 , the multiple sub-coupling regions include a two-dimensional grating region 301 and a one-dimensional grating region 302; wherein the two-dimensional grating region 301 is located in the middle of the outcoupling region 3; the one-dimensional grating region 302 is set to be at least two and are arranged on opposite sides of the two-dimensional grating region 301; the transition grating region 303 is located between the two-dimensional grating region 301 and the one-dimensional grating region 302.

[0092] According to the above example, the two-dimensional grating area 301 includes a plurality of parallelogram gratings, and the plurality of parallelogram gratings are arranged to form a first target shape; the one-dimensional grating area 302 includes a plurality of second strip gratings, and the second strip gratings do not have the grooves 4, and the plurality of second strip gratings are arranged to form a second target shape.

[0093] The outcoupling zone 3 needs to have both pupil expansion and outcoupling functions. According to the above example, the outcoupling zone 3 includes different types of gratings arranged in partitions, and a transition grating zone with diffraction behavior between the two-dimensional grating zone and the one-dimensional grating zone is introduced between the two-dimensional grating zone and the one-dimensional grating zone. The transition grating zone is a two-dimensional grating structure design that can improve optical performance.

[0094] See also Figure 3 A two-dimensional grating is set at the center of the outcoupling area 3 to perform two-dimensional pupil expansion on the central field of view light, and a one-dimensional grating is used at the outermost edge of the outcoupling area 3 to couple the light out, and a first strip grating 31 with grooves 4 is used in the transition area from the center to the edge to perform the transition of the diffraction behavior, so that the light energy of the entire outcoupling area 3 forms a reasonable transition from the central field of view to the edge field of view, so that the light energy in the outcoupling area 3 can be reasonably distributed, which can improve the light efficiency.

[0095] In one example of this application, see Fig.14 , the outcoupling region 3 is arranged on a surface of the light-guiding substrate 1; in the outcoupling region 3: the opposite sides of the grating structure form angles A and B with the surface of the light-guiding substrate 1 respectively, and the angles are 20° to 160°; or, the grating structure is a step grating.

[0096] According to the grating structure design of the outcoupling area in the above example, an anti-light leakage effect can be formed in the outcoupling area 3, which can provide users with a better immersive experience.

[0097] According to another aspect of an embodiment of the present application, an optical module is provided, wherein the optical module comprises the light guide device and an optical engine as described above, wherein the optical engine is used to project light or an image into the light guide device.

[0098] The light energy in the entire outcoupling zone 3 can be distributed more flexibly and reasonably from the middle to the edge, forming a gradual transition of light energy in the outcoupling zone 3, which can improve the diffraction efficiency of the outcoupling zone 3 and thus improve the imaging quality.

[0099] The imaging light emitted by the optical machine should be able to cover the entire coupling-in area 2 .

[0100] The imaging light emitted by the optical machine may be monochromatic light or polychromatic light.

[0101] According to another aspect of the embodiments of the present application, a head-mounted display device is provided. The head-mounted display device includes a housing and the optical module as described above.

[0102] The head-mounted display device is, for example, an AR head-mounted device, including AR glasses or an AR helmet, etc., and the embodiments of the present application do not impose specific limitations on this.

[0103] The specific implementation of the optical module and the head-mounted display device of the embodiments of the present application can refer to the above-mentioned embodiments of the light guide device, so it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0104] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0105] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A light guide device, characterized in that: It comprises a light-guiding substrate (1) and an incoupling region (2) and an outcoupling region (3) arranged on the light-guiding substrate (1); The outcoupling area (3) is used to expand the pupil of the light from the incoupling area (2) and couple it out; The outcoupling region (3) comprises at least one first strip grating (31) with grooves (4), and the grooves (4) are arranged in at least two and are arranged on two opposite sides of the first strip grating (31). The grooves (4) can be used to increase the diffraction order of the first strip grating (31) and form a target diffraction efficiency corresponding to the diffraction order, so that light propagating to the position of the first strip grating (31) can be transformed from the original single-side diffraction on the first strip grating (31) to the additional diffraction on the other side of the first strip grating (31).

2. The light guide device according to claim 1, characterized in that: The outcoupling region (3) comprises a plurality of mutually independent sub-outcoupling regions; A plurality of the first stripe gratings (31) are provided and are located in at least one of the sub-outcoupling regions to form a transition grating region (303) between a two-dimensional grating region and a one-dimensional grating region.

3. The light guide device according to claim 2, characterized in that: In one sub-coupling area, the first strip grating (31) is arranged in plurality; The plurality of first strip gratings (31) are arranged adjacently and at intervals to form a partitioned arrangement in the sub-coupling area; or The plurality of first strip gratings (31) are adjacent and sequentially connected to form a whole in the sub-coupling region.

4. The light guide device according to any one of claims 1 to 3, characterized in that: The width of the first strip grating (31) is L, and the depth of the groove (4) is ≤ L; When the groove depth of the groove (4) is L, the groove (4) penetrates the first strip grating (31) in the width direction of the first strip grating (31), so that the diffraction efficiency of the increased diffraction order on the other side of the first strip grating (31) reaches a maximum value.

5. The light guide device according to any one of claims 1 to 3, characterized in that: The groove (4) comprises a groove bottom (41) and a groove wall extending from the groove bottom (41); The groove wall comprises a first surface (42) and a second surface (43) opposite to each other, the first surface (42) and the groove bottom (41) form a first angle A1, the second surface (43) and the groove bottom (41) form a second angle A2, the first angle A1 and the second angle A2 are 0° to 180°; The angle between the groove bottom (41) and the side edge (311) of the first strip grating (31) along the length direction is 0° to 89°; The sizes of the first surface (42) and the second surface (43) along the width direction of the first stripe grating (31) are 0 to 1000 nm.

6. The light guide device according to claim 2, characterized in that: The plurality of sub-outcoupling regions include a two-dimensional grating region (301) and a one-dimensional grating region (302); Wherein, the two-dimensional grating region (301) is located in the middle of the outcoupling region (3); The one-dimensional grating area (302) is provided in at least two portions and is disposed on two opposite sides of the two-dimensional grating area (301); The transition grating region (303) is located between the two-dimensional grating region (301) and the one-dimensional grating region (302).

7. The light guide device according to claim 6, characterized in that: The two-dimensional grating region (301) comprises a plurality of parallelogram gratings, and the plurality of parallelogram gratings are arranged to form a first target shape; The one-dimensional grating region (302) includes a plurality of second strip gratings, and the second strip gratings do not have the grooves (4), and the plurality of second strip gratings are arranged to form a second target shape.

8. The light guide device according to claim 1, characterized in that: The outcoupling region (3) is arranged on a surface of the light-guiding substrate (1); In the outcoupling region (3), two opposite sides of the grating structure respectively form an angle with the surface of the light-guiding substrate (1), and the angle is 20° to 160°; or, the grating structure is a step grating.

9. An optical module, characterized in that: include: The light guide device according to any one of claims 1 to 8; as well as An optical machine is used to project light or an image into the light guiding device.

10. A head mounted display device, characterized in that: include: a housing; and The optical module as claimed in claim 9.

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