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. Wherein the coupling-out area is used for carrying out pupil expansion and coupling-out on light rays from the coupling-in area, the coupling-out area comprises at least a first area, the first area is composed of at least two adjacent one-dimensional gratings, a target interval L can be formed between any two adjacent one-dimensional gratings, and the target interval L is larger than or equal to 0 and smaller than or equal to 4 mm. According to the optical scheme provided by the embodiment of the invention, the processing difficulty of the coupling-out region can be reduced.

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 prior art, diffraction waveguide devices usually adopt a two-dimensional grating pupil expansion and coupling design, and the light propagation path is that the light coupled into the waveguide expands to both sides when encountering the two-dimensional grating. However, due to the symmetry of light diffraction and the fact that the pupil expansion direction of the two-dimensional grating is fixed and the angles in two directions cannot be adjusted, there will always be at least one corner on the two-dimensional grating with a dark angle of the field of view, which seriously affects the uniformity and integrity of the image displayed by the optical waveguide, and thus affects the user experience. In addition, the design of the two-dimensional grating is relatively complex, which will increase the production cost. 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.

[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] Among them, the out-coupling zone is used to expand the pupil and couple out the light from the coupling-in zone, and the out-coupling zone includes at least a first area, and the first area is composed of at least two adjacent one-dimensional gratings. A target interval L can be formed between any two adjacent one-dimensional gratings, and the target interval L is 0≤L≤4mm.

[0006] Optionally, the first region is located in the middle of the outcoupling region, and within the first region, grating vectors of any two adjacent one-dimensional gratings form a mirror-symmetric structure and the grating vectors of the two form a target angle.

[0007] Optionally, the target angle is 50° to 70°.

[0008] Optionally, the first region includes 2 to 8 one-dimensional gratings, and the number of the one-dimensional gratings is an even number.

[0009] Optionally, the outcoupling region further includes a second region and a third region, the second region and the third region are arranged on two opposite sides of the first region, and the second region and the third region include a one-dimensional grating or a two-dimensional grating.

[0010] Optionally, the first region includes a first grating, a second grating, a third grating and a fourth grating which are adjacently arranged, and the first grating, the second grating, the third grating and the fourth grating are all one-dimensional gratings;

[0011] The first grating and the second grating are located in the middle of the first region, the grating vectors of the first grating and the second grating form a mirror-symmetrical structure, and the target angle formed by the grating vectors of the two is 50° to 70°;

[0012] The third grating is located on a side of the first grating away from the second grating, the fourth grating is located on a side of the second grating away from the first grating, the third grating has the same grating vector as the second grating, and the fourth grating has the same grating vector as the first grating.

[0013] Optionally, the outcoupling region further includes a second region and a third region, the second region and the third region are respectively arranged on two opposite sides of the first region, the second region includes a fifth grating, and the third region includes a sixth grating;

[0014] The fifth grating and the sixth grating are one-dimensional gratings. The fifth grating has the same grating vector as the first grating, and the sixth grating has the same grating vector as the second grating.

[0015] Optionally, there are intervals between the first grating and the second grating, between the first grating and the third grating, between the second grating and the fourth grating, between the third grating and the fifth grating, and between the fourth grating and the sixth grating.

[0016] Optionally, the coupling-in region is provided with a coupling-in grating, which is used to couple light into the light-guiding substrate and make the light totally reflected in the light-guiding substrate and propagate to the decoupling region; the coupling-in grating is a one-dimensional grating and has a first vector K1, and two adjacent one-dimensional gratings in the first region respectively have a second vector K2 and a third vector K3, and the first vector K1, the second vector K2 and the third vector K3 constitute an isosceles triangle with a vector angle of 50° to 70°.

[0017] In a second aspect, the present application provides an optical module. The optical module comprises:

[0018] The light guiding device according to the first aspect; and

[0019] An optical machine is used to project light or an image into the light guiding device.

[0020] In a third aspect, the present application provides a head mounted display device. The head mounted display device comprises:

[0021] a housing; and

[0022] An optical module as described in the second aspect.

[0023] The beneficial effects of this application are:

[0024] According to the light-guiding device provided in the embodiment of the present application, which is a diffraction light waveguide solution, a two-dimensional pupil expansion and outcoupling function is realized by combining at least two one-dimensional gratings in the outcoupling area. When the light from the coupling-in area propagates to the outcoupling area, the light can be effectively expanded in two different dimensional directions and can cover all positions of the entire outcoupling area, which can increase the light-emitting area, so that the human eye can obtain a clear and complete image within a larger field of view, thereby improving the user's visual experience.

[0025] 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

[0026] 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.

[0027] Figure 1 A schematic diagram of the structure of a light guide device provided in an embodiment of the present application;

[0028] Figure 2 A schematic diagram of a grating vector closed structure of a light guide device provided in an embodiment of the present application;

[0029] Figure 3 One of the structural schematic diagrams of the first region of the light guide device provided in an embodiment of the present application;

[0030] Figure 4 A second structural schematic diagram of the first region of the light guide device provided in an embodiment of the present application;

[0031] Figure 5 A third structural schematic diagram of the first region of the light guide device provided in an embodiment of the present application;

[0032] Figure 6 One of the top views of the light guide device provided in the embodiment of the present application;

[0033] Figure 7 This is the second top view of the light guide device provided in the embodiment of the present application.

[0034] Description of reference numerals:

[0035] 1. Light-guiding substrate; 2. Incoupling region; 3. Outcoupling region; 31. First grating; 32. Second grating; 33. Third grating; 34. Fourth grating; 35. Fifth grating; 36. Sixth grating; 301. First region; 01. First diffraction light; 02. Second diffraction light; 03. Third diffraction light; 04. Fourth diffraction light; 05. Outcoupling light; 06. Fifth diffraction light. DETAILED DESCRIPTION

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Among various forms of head-mounted display devices, AR devices are taken as an example. AR devices usually include a micro display screen and an optical module. Commonly used optical elements in the optical module of AR devices include prisms, free-form lenses, and optical waveguide devices. Among the above-mentioned optical elements, optical waveguide devices include geometric optical waveguides and diffraction optical waveguides. Due to the good optical performance of diffraction optical waveguides, they have been widely used in AR devices.

[0043] According to an embodiment of the present application, a light guide device is provided. The light guide device is, for example, an optical waveguide device, and the optical waveguide device is, for example, a diffraction optical waveguide. The light guide device provided in the embodiment of the present application can be applied to, for example, a wearable device.

[0044] The wearable device includes a head-mounted display device, such as AR smart glasses, AR helmets, etc. The specific form of the head-mounted display device is not limited in this application.

[0045] The light guide device provided in the embodiment of the present application is shown in FIG. Figure 1 The light guide device comprises a light guide substrate 1 and an incoupling region 2 and an outcoupling region 3 arranged on the light guide substrate 1. The outcoupling region 3 is used to expand the pupil of the light from the incoupling region 2 and couple it out. Figures 3 to 7 The outcoupling region 3 includes at least a first region 301, and the first region 301 is composed of at least two adjacent one-dimensional gratings, and a target interval L can be formed between any two adjacent one-dimensional gratings, and the target interval L is 0≤L≤4mm.

[0046] It should be noted that, in the first region 301 , two adjacent one-dimensional gratings may form a basic grating unit.

[0047] According to the light guide device provided in the above embodiment of the present application, an incoupling area 2 and an outcoupling area 3 are respectively provided on the light guide substrate 1. External light, such as light with image information projected by an optical machine, can enter the light guide substrate 1 through the incoupling area 2, and the light will propagate to the outcoupling area 3 in the light guide substrate 1 in a total reflection manner. When the light propagates to the outcoupling area 3 and encounters the first area 301, the first area 301 can expand the pupil of the light in two different dimensional directions, see Figure 6 , and finally the light can cover the first area 301 , so that the light output area of ​​the outcoupling zone 3 , especially the first area 301 , can be increased, thereby improving the visual experience of the user.

[0048] The traditional two-dimensional grating pupil expansion and outcoupling method cannot achieve the effect of making the light cover the entire outcoupling area. Although the two-dimensional grating can expand the pupil of light in two different directions, these two directions are fixed to be perpendicular to each other and cannot be adjusted. During the pupil expansion process, the light cannot propagate to certain positions in the outcoupling area. There will always be some corners with dark corners of the field of view, resulting in part of the outcoupling area being able to emit light, while other parts may not be able to emit light. The human eye will move within a certain range, and it needs to be able to see the light during the movement. It can be seen that the two-dimensional grating pupil expansion will limit the use range of the human eye, that is, the eyebox is smaller. In particular, when the central area of ​​the outcoupling area uses a two-dimensional grating to expand the pupil, the small eyebox is particularly obvious, and a good imaging effect cannot be achieved.

[0049] In the light-guiding device provided in the embodiment of the present application, the coupling-out region 3 is designed to include a first region 301, wherein at least two adjacent one-dimensional gratings are used in the first region 301, and a target interval can be designed between the two adjacent one-dimensional gratings, and the target interval is, for example, less than 4 mm, that is, less than the pupil aperture of the human eye, which is conducive to increasing the eyebox, especially the lateral eyebox. It should be noted that when the target interval is greater than 4 mm, the image seen by the human eye will be missing and incomplete.

[0050] The first area 301 is designed to expand the pupil by combining two one-dimensional gratings. The advantage is that each one-dimensional grating has a single vector direction, and the vector angle of two adjacent one-dimensional gratings can be adjusted by combination, so that the pupil expansion direction of the light can be flexibly adjusted, which is conducive to making the light spread as much as possible in the first area 301, that is, each part and corner of the first area 301 can emit light, which is conducive to obtaining a larger and more complete eyebox value. The human eye can see a clear and complete image in the entire field of view, thereby improving the user's visual experience.

[0051] The light guide device of the embodiment of the present application comprises a light guide substrate 1 and an incoupling region 2 and an outcoupling region 3 arranged on the light guide substrate 1. The incoupling region 2 and the outcoupling region 3 may be arranged on the same side surface of the light guide substrate 1. Figure 1 Of course, the coupling-in region 2 and the coupling-out region 3 may also be distributed on both sides of the light-guiding substrate 1. In the embodiment of the present application, the relative position relationship between the coupling-in region 2 and the coupling-out region 3 is not limited, as long as the light can be coupled into the light-guiding substrate 1 through the coupling-in region 2, and propagated to the coupling-out region 3 by total reflection in the light-guiding substrate 1, and then coupled out through the coupling-out region 3.

[0052] Optionally, in the light-guiding device provided in the embodiment of the present application, the light-guiding substrate 1 may be a single-layer color waveguide structure or a multi-layer color waveguide structure, which is not limited in the embodiment of the present application.

[0053] See respectively Figures 3 to 5 There may be many combinations of the two one-dimensional gratings in the first region 301, which is not limited in the embodiment of the present application.

[0054] In addition, forming a two-dimensional pupil expansion effect by combining two one-dimensional gratings in the first area 301 of the outcoupling region 3 can improve the degree of freedom of pupil expansion direction during two-dimensional pupil expansion.

[0055] In some examples of this application, see Figure 6 and Figure 7The first region 301 is located in the middle of the outcoupling region 3. In the first region 301, the grating vectors of any two adjacent one-dimensional gratings form a mirror-symmetrical structure and the grating vectors of the two form a target angle.

[0056] According to the above example, the first area 301 is located in the middle of the outcoupling area 3, for example, and the light in the central field of view can be dilated, and the light after pupil dilation can cover the first area 301, thereby improving the imaging quality of the central field of view.

[0057] In the light guide device provided in the embodiment of the application, the first region 301 is designed to include at least two one-dimensional gratings, and the two one-dimensional gratings can be arranged adjacently and at intervals. In order to achieve a better pupil expansion effect, the angle range formed by the grating vectors of the two one-dimensional gratings can be controlled. In this way, in the first region 301, the light can be made to expand the pupil in a two-dimensional manner in a specific direction according to a set angle, so that the light can more completely cover the first coupled region 301, and defects of the two-dimensional grating when expanding the pupil can be avoided.

[0058] The first region 301 can be distributed in the outcoupling region 3 in any shape and position, so that the structural design of the entire light guide device is more flexible and has a higher degree of freedom. As a preferred embodiment of the present application, the first region 301 is located in the central region of the outcoupling region 3.

[0059] In the first region 301, the grating vectors of two adjacent one-dimensional gratings form a mirror-symmetric structure, see Figures 3 to 5 The symmetry axes of the two one-dimensional gratings can be along different directions, which is not limited in the present application.

[0060] Optionally, the target angle is 50° to 70°.

[0061] Take the example that the first region 301 includes two adjacent one-dimensional gratings arranged at an interval, see Figure 4 The grating vector angle of the two one-dimensional gratings can be designed to be 50° to 70°, for example. In this case, when the light in the light-guiding substrate 1 propagates to the first area 301, it can expand along two different dimensions and cover the first area 301 as much as possible, and each part of the first area 301 can emit light.

[0062] The first region 301 may include, for example, 2 to 8 one-dimensional gratings, and the number of the one-dimensional gratings is an even number.

[0063] The size of the first region 301 can be reasonably designed according to the size of the decoupling region 3. The first region 301 can occupy the entire decoupling region 3 or be a partial region of the entire decoupling region 3.

[0064] For example, the first region 301 is the middle region of the outcoupling region 3. According to the size of the first region 301, a certain number of one-dimensional gratings can be designed, and according to the size of the outcoupling region 3 in general, in the middle region thereof, for example, 2 to 8 one-dimensional gratings can be provided, so that the light can cover the entire first region 301 without any dark angle in the field of view.

[0065] The one-dimensional gratings in the first area 301 are designed to be combined in pairs to achieve two-dimensional pupil expansion. In order to achieve a better pupil expansion effect, it is more preferred that the number of the one-dimensional gratings is an even number.

[0066] In some examples of this application, see Figure 6 and Figure 7 The outcoupling region 3 further includes a second region and a third region, the second region and the third region are arranged on two opposite sides of the first region 301, and the second region and the third region include a one-dimensional grating or a two-dimensional grating.

[0067] According to the above example, the outcoupling region 3 may include, in addition to the first region 301, a second region and a third region located on the left and right sides of the first region 301. Figure 6 and Figure 7 The second area and the third area are located at the edge of the outcoupling area 3. A single or multiple two-dimensional gratings can be used in these two areas. Of course, multiple one-dimensional gratings can also be used to achieve pupil expansion and outcoupling of light in the edge field of view to adjust the imaging condition of the edge field of view.

[0068] In one example of this application, see Figure 6 The first region 301 includes a first grating 31, a second grating 32, a third grating 33 and a fourth grating 34 which are arranged adjacent to each other. The first grating 31, the second grating 32, the third grating 33 and the fourth grating 34 are all one-dimensional gratings. The first grating 31 and the second grating 32 are located in the middle of the first region 301. The grating vectors of the first grating 31 and the second grating 32 form a mirror-symmetric structure and the target angle formed by the grating vectors of the two is 50° to 70°. The third grating 33 is located on the side of the first grating 31 away from the second grating 32, and the fourth grating 34 is located on the side of the second grating 32 away from the first grating 31. The grating vectors of the third grating 33 and the second grating 32 are the same, and the grating vectors of the fourth grating 34 and the first grating 31 are the same.

[0069] Based on the above example, see Figure 6 , Figure 6The optical behavior when the interval between the one-dimensional gratings in the first region 301 is 0 is shown, as follows:

[0070] The coupling-in area 2 receives the light projected by the external optical machine, and couples the light into the light-guiding substrate 1, generating the first diffraction light 01 and the second diffraction light 02 propagating toward the coupling-out area 3. After the first diffraction light 01 and the second diffraction light 02 are incident on the first area 301, they will propagate the third diffraction light 03 and the fourth diffraction light 04 to one side when encountering the combined one-dimensional grating, and continue to propagate in the original direction, thereby achieving an effect equivalent to two-dimensional pupil expansion.

[0071] Because of symmetry, only the fourth diffraction light 04 is described here. When the fourth diffraction light 04 is incident on the adjacent one-dimensional grating in the first region 301, it generates an outcoupling light 05 and continues to propagate in the original direction. The fourth diffraction light 04 continues to transmit, and when it encounters a grating with the same vector direction as the grating encountered for the first time, it generates a fifth diffraction light 06 and continues to propagate in the original direction. The diffraction direction of the fifth diffraction light 06 is the same as that of the second diffraction light 02. Finally, the light propagating to both sides covers the entire first region 301, and even covers the entire outcoupling area 3.

[0072] Based on the above example, see Figure 6 The outcoupling region 3 also includes a second region and a third region, the second region and the third region are arranged on two opposite sides of the first region 301, the second region includes a fifth grating 35, and the third region includes a sixth grating 36; the fifth grating 35 and the sixth grating 36 are one-dimensional gratings, the fifth grating 35 has the same grating vector as the first grating 31, and the sixth grating 36 has the same grating vector as the second grating 32.

[0073] Wherein, one-dimensional gratings are arranged in both the second region and the third region, but the grating vector directions of the one-dimensional gratings are different, and the one-dimensional grating in the second region can form a basic grating unit with the one-dimensional grating in the first region 301 close to the second region, and the two can achieve a two-dimensional pupil expansion effect. Similarly, the one-dimensional grating in the third region can form a basic grating unit with the one-dimensional grating in the first region 301 close to the third region, and the two can also achieve a two-dimensional pupil expansion effect. Thus, pupil expansion and outcoupling of light in the edge field of view are achieved.

[0074] According to the above example, in a more preferred example, see Figure 7There are gaps between the first grating 31 and the second grating 32 , between the first grating 31 and the third grating 33 , between the second grating 32 and the fourth grating 34 , between the third grating 33 and the fifth grating 35 , and between the fourth grating 34 and the sixth grating 36 .

[0075] The area for pupil dilation in two dimensions is composed of one-dimensional gratings, and the interval is controlled below 4mm, which can increase the eyebox. Figure 7 The solution shown can increase the lateral eyebox, but it should be noted that the interval cannot be greater than 4 mm, otherwise some areas may not be visible to the human eye.

[0076] In some examples of this application, see Figure 1 , Figure 6 and Figure 7 The coupling-in region 2 is provided with a coupling-in grating, and the coupling-in region 2 is used to couple light into the light-guiding substrate 1 and make the light propagate to the coupling-out region 3 through total reflection in the light-guiding substrate 1. The coupling-in grating is a one-dimensional grating and has a first vector K1. Two adjacent one-dimensional gratings in the first region 301 have a second vector K2 and a third vector K3, respectively. The first vector K1, the second vector K2 and the third vector K3 form an isosceles triangle with a vector angle of 50° to 70°. See Figure 2 .

[0077] Two adjacent gratings in the first region 301 may form a basic grating unit.

[0078] According to the above example, two adjacent one-dimensional gratings in the first region 301 have a second vector K2 and a third vector K3, respectively, and the first vector K1, the second vector K2 and the third vector K3 form an isosceles triangle with a vector angle of 50° to 70°. This design can ensure that the exit angle of the light when coupled out from the coupling-out region 3 is consistent with the incident angle of the light when coupled in through the coupling-in region 2, which is conducive to expanding the field of view of the light guide device.

[0079] In the light-guiding device provided in the embodiment of the present application, the diffraction gratings in the coupling-in region 2 and the coupling-out region 3 may be volume holographic gratings, surface relief gratings or photonic crystals, and the like.

[0080] The above-mentioned gratings are all diffraction gratings. A suitable type of diffraction grating can be selected according to needs and applied to the coupling-in region and / or coupling-out region of the light-guiding device. This application does not impose any specific limitation on this.

[0081] 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.

[0082] The imaging light emitted by the optical machine is projected onto the coupling-in area 2 of the light guide device. Figure 2 The coupling-in area 2 can be used to couple the imaging light emitted by the machine into the light-guiding substrate 1, and the coupled light can be propagated to the coupling-out area 3 in a state of total reflection. The coupling-out area 3 can dilate the propagated light and couple it out. The area for realizing two-dimensional pupil expansion introduced in the coupling-out area 3 is composed of a one-dimensional grating interval, and the interval distance is between 0 and 4 mm.

[0083] The light emitted by the optical machine should be able to cover the entire coupling-in area 2 .

[0084] The light emitted by the optical machine may be monochromatic light or polychromatic light.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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 zone (3) is used to expand the pupil of the light from the coupling-in zone (2) and couple it out, the outcoupling zone (3) includes at least a first area (301), and the first area (301) is composed of at least two adjacent one-dimensional gratings, and a target interval L can be formed between any two adjacent one-dimensional gratings, and the target interval L is 0≤L≤4mm.

2. The light guide device according to claim 1, characterized in that: The first region (301) is located in the middle of the outcoupling region (3), and within the first region (301), grating vectors of any two adjacent one-dimensional gratings form a mirror-symmetric structure and the grating vectors of the two form a target angle.

3. The light guide device according to claim 2, characterized in that: The target angle is 50° to 70°.

4. The light guide device according to claim 1, characterized in that: The first region (301) includes 2 to 8 one-dimensional gratings, and the number of the one-dimensional gratings is an even number.

5. The light guide device according to any one of claims 1 to 4, characterized in that: The outcoupling region (3) further comprises a second region and a third region, wherein the second region and the third region are arranged on two opposite sides of the first region (301), and the second region and the third region comprise a one-dimensional grating or a two-dimensional grating.

6. The light guide device according to claim 5, characterized in that: The first region (301) comprises a first grating (31), a second grating (32), a third grating (33) and a fourth grating (34) which are arranged adjacent to each other, and the first grating (31), the second grating (32), the third grating (33) and the fourth grating (34) are all one-dimensional gratings; The first grating (31) and the second grating (32) are located in the middle of the first area (301), the grating vectors of the first grating (31) and the second grating (32) form a mirror-symmetrical structure, and the target angle formed by the grating vectors of the two is 50° to 70°; The third grating (33) is located on a side of the first grating (31) away from the second grating (32), the fourth grating (34) is located on a side of the second grating (32) away from the first grating (31), the third grating (33) has the same grating vector as the second grating (32), and the fourth grating (34) has the same grating vector as the first grating (31).

7. The light guide device according to claim 6, characterized in that: The outcoupling region (3) further comprises a second region and a third region, the second region and the third region are arranged on two opposite sides of the first region (301), the second region comprises a fifth grating (35), and the third region comprises a sixth grating (36); The fifth grating (35) and the sixth grating (36) are one-dimensional gratings. The fifth grating (35) has the same grating vector as the first grating (31), and the sixth grating (36) has the same grating vector as the second grating (32).

8. The light guide device according to claim 7, characterized in that: There are spaces between the first grating (31) and the second grating (32), between the first grating (31) and the third grating (33), between the second grating (32) and the fourth grating (34), between the third grating (33) and the fifth grating (35), and between the fourth grating (34) and the sixth grating (36).

9. The light guide device according to claim 1, characterized in that: The coupling-in region (2) is provided with a coupling-in grating, and the coupling-in region (2) is used to couple light into the light-guiding substrate (1) and to make the light be totally reflected in the light-guiding substrate (1) and propagate to the coupling-out region (3); The coupling grating is a one-dimensional grating and has a first vector K1. Two adjacent one-dimensional gratings in the first area have a second vector K2 and a third vector K3 respectively. The first vector K1, the second vector K2 and the third vector K3 form an isosceles triangle with a vector angle of 50° to 70°.

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

11. A head mounted display device, characterized in that: include: case; as well as The optical module as claimed in claim 10.

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