Light guide device and head-mounted display equipment

Abstract

The embodiment of the invention provides a light guide device and head-mounted display equipment. The light guide device comprises a substrate, a coupling-in area and a coupling-out area, the coupling-in area and the coupling-out area are arranged on the substrate, a light splitting element is embedded in one side, close to the coupling-out area, in the substrate, and the light splitting element is located on a total reflection light path from the coupling-in area to the coupling-out area; the coupling area is used for coupling light into the substrate and enabling the light to be totally reflected and propagated in the substrate; the light splitting element is used for carrying out at least one time of beam splitting and pupil expanding on the light transmitted from the coupling-in area; the coupling-out area is used for carrying out beam splitting and pupil expanding on the light passing through the light splitting element and then coupling out the light. According to the light guide device provided by the embodiment of the invention, the light splitting element is introduced below the coupling-out region in the substrate, so that the uniformity of the coupling-out light can be improved.

Description

Technical Field

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

[0002] In order to meet the requirements of users with different eye distances, the light guide device needs to perform pupil dilation when coupling out light, so that the image generated by the optical machine can be seen within a certain range. The principle of pupil dilation is that while the light is coupled out at a certain position of the coupling grating, a part of the light (the 0th diffraction order part of the coupling grating) continues to propagate in the original direction, and after two total reflections, it is partially coupled out again on the coupling grating and partially propagates in the original direction, and so on. However, after the pupil dilation effect, the existing light guide device has the phenomenon of uneven coupling light within a larger eyebox. Summary of the invention

[0003] The purpose of this application is to provide a new technical solution for a light-guiding device and a head-mounted display device.

[0004] In a first aspect, an embodiment of the present application provides a light guide device. The light guide device includes a substrate and an incoupling region and an outcoupling region arranged on the substrate, a light splitting element is embedded in the substrate on a side close to the outcoupling region, and the light splitting element is located on a total reflection optical path from the incoupling region to the outcoupling region;

[0005] The coupling-in area is used to couple the light into the substrate and make the light propagate through total reflection in the substrate; the beam splitter element is used to perform at least one beam splitting and pupil expansion on the light propagating through the coupling-in area; and the coupling-out area is used to perform beam splitting and pupil expansion on the light passing through the beam splitter element and then couple it out.

[0006] Optionally, the light splitting element includes at least one layer of semi-reflective and semi-transmissive membrane, and the light splitting element is horizontally arranged in the substrate.

[0007] Optionally, the light splitting element is a single-layer semi-reflective and semi-transparent membrane. In the thickness direction r2 of the substrate, the substrate is divided into two layers by the single-layer semi-reflective and semi-transparent membrane, and the thicknesses are d and d, respectively. 1 and d 2 ;

[0008] The position of the light splitting element in the substrate satisfies:

[0009] 2d min tanθ>R IC ;

[0010] Among them, d min is d 1 and d 2θ is the angle between the propagation direction r1 of the light coupled into the substrate through the coupling region and the thickness direction r2 of the substrate, R IC is the aperture of the coupling zone.

[0011] Optionally, the light splitting element comprises N layers of semi-reflective and semi-transparent films, and N≥2. In the thickness direction r2 of the substrate, the substrate is divided into N+1 layers by the multiple layers of the semi-reflective and semi-transparent films, and the thicknesses are d 1 , d 2 , d 3 ……d N+1 ;

[0012] The position of the light splitting element in the substrate satisfies:

[0013] 2d min tanθ>R IC ;

[0014] Among them, d min is d 1 , d 2 , d 3 ……d N+1 θ is the angle between the propagation direction r1 of the light coupled into the substrate through the coupling region and the thickness direction r2 of the substrate, R IC is the aperture of the coupling zone.

[0015] Optionally, in the thickness direction r2 of the substrate, the light splitting element is arranged opposite to the outcoupling region forming portion.

[0016] Optionally, the light input end A1 of the beam splitter element extends to the outside of the light input end A2 of the outcoupling region, and the light transmission end B2 of the outcoupling region extends to the outside of the light transmission end B1 of the beam splitter element.

[0017] Optionally, along the arrangement direction of the beam splitter element, a target interval is formed between the light transmission end B1 of the beam splitter element and the light transmission end B2 of the outcoupling region, and the target interval is no greater than 4 mm.

[0018] Optionally, the light splitting element is a semi-reflective and semi-transparent membrane with a gradually changing transmittance.

[0019] Optionally, the light-guiding device further comprises a turning grating, wherein the turning grating is located on a total reflection light path between the coupling-in region and the coupling-out region, and the turning grating is used to receive light from the coupling-in region and turn the light to propagate to the coupling-out region.

[0020] Optionally, the turning grating is a one-dimensional grating.

[0021] Optionally, the coupling-in region comprises a one-dimensional grating, and the coupling-out region comprises a one-dimensional grating or a two-dimensional grating.

[0022] Optionally, the light guiding device is an optical waveguide element.

[0023] In a second aspect, an embodiment of the present application provides a head mounted display device. The head mounted display device comprises:

[0024] shell;

[0025] Optical machinery; and

[0026] A light guiding device as described in the first aspect.

[0027] The beneficial effects of this application are:

[0028] According to the light-guiding device provided in the embodiment of the present application, a beam splitter element is introduced into the base of the light-guiding device and below the outcoupling area. The introduction of the beam splitter element allows the light to be beam split and the pupil to be expanded in the outcoupling area while also being beam split and the pupil to be expanded at the beam splitter element, thereby avoiding the problem of uneven outcoupling. Even within a larger eyebox, the uniformity of the outcoupling light can be guaranteed, thereby improving the visual experience.

[0029] 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

[0030] 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.

[0031] Figure 1 A schematic diagram of the structure and light path propagation of the light guide device provided in an embodiment of the present application;

[0032] Figure 2 Schematic diagram of the structure and light path propagation of a traditional light-guiding device.

[0033] Description of reference numerals:

[0034] 1. Incoupling region; 2. Outcoupling region; 3. Beam splitting element; 4. Substrate; 01. Human eye. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] The light guide device and the head mounted display device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0041] According to one aspect of an embodiment of the present application, a light guide device is provided, which may be, for example, a diffractive light waveguide element, or other types of light transmission elements, and may be suitable for use in augmented reality AR devices, for transmitting light emitted by a projection optical machine. The augmented reality AR device may include AR glasses or an AR helmet, etc., and the embodiment of the present application does not limit the specific form of the head-mounted display device.

[0042] The light guide device proposed in the embodiment of the present application, see Figure 1 The light guide device includes a substrate 4 and an incoupling area 1 and an outcoupling area 2 arranged on the substrate 4. A beam splitter 3 is embedded in the substrate 4 on a side close to the outcoupling area 2, and the beam splitter 3 is located on the total reflection optical path from the incoupling area 1 to the outcoupling area 2. The incoupling area 1 is used to couple light into the substrate 4 and make the light propagate through total reflection in the substrate 4; the beam splitter 3 is used to perform at least one beam splitting and pupil expansion process on the light propagated through the incoupling area 1; and the outcoupling area 2 is used to couple out the light after beam splitting and pupil expansion after the light passes through the beam splitter 3.

[0043] According to the light guide device provided in the above embodiment, see Figure 1 , which at least comprises a substrate 4, an incoupling region 1, an outcoupling region 2 and a beam splitter 3. Specifically, a beam splitter 3 is embedded in the substrate 4, and the beam splitter 3 is located below the outcoupling region 2, for example.

[0044] The coupling-in area 1 is arranged on the substrate 4, and is responsible for coupling the light projected by the external optical machine into the substrate 4, and allowing the coupled light to be fully reflected and propagated on the substrate 4. The coupling-out area 2 is also arranged on the substrate 4, and can be used to couple out the light propagated to the coupling-out area 2, so that the human eye 01 can view the projected image on one side of the coupling-out area 2.

[0045] Optionally, the coupling-in region 1 and the coupling-out region 2 may be located on the same surface of the light-guiding device, or may be located on two opposite surfaces of the light-guiding device, which is not limited in the present application.

[0046] The light splitting element 3 can be used to transmit a part of the light and reflect a part of the light at the same time.

[0047] For the light guide device provided in the above embodiments of the present application, see Figure 1 A beam splitter element 3 is introduced into the substrate 4 and below the outcoupling area 2. The introduction of the beam splitter element 3 allows the light to be beam split and pupil expanded at the beam splitter element 3 while the light is beam split and pupil expanded at the outcoupling area 2, thereby avoiding the problem of uneven outcoupling. The design of the present application can ensure the uniformity of the outcoupling light even within a larger eyebox, thereby improving the visual experience.

[0048] Specifically, see Figure 1 , the light coupled into the substrate 4 through the coupling-in area 2 propagates in a state of total reflection. After the light meets the beam splitter 3, part of the light passes through the beam splitter 3 and propagates to the coupling-out area 2 for pupil expansion and coupling-out, and part of the light is reflected to the bottom of the substrate 4, and after modulation, it is reflected to the beam splitter 3 again. At this time, this part of the light can pass through the beam splitter 3 and propagate to the coupling-out area 2 for pupil expansion and coupling-out. In this way, the coupled light undergoes at least two beam splitting and pupil expansion processes, thereby effectively avoiding the problem of uneven coupling. According to Figure 1 The middle out-coupling area 2 shows the out-coupling light distribution. The light distribution seen by the human eye 01 within a certain range, namely the eyebox, is relatively uniform.

[0049] According to the light-guiding device provided in the embodiment of the present application, the shape of the coupling-in region 1 may not be restricted and may be designed into any shape as required to match optical machines of various shapes, so that the design of the coupling-in region 1 may be very flexible.

[0050] According to the light guide device provided in the embodiment of the present application, when the light passes through the outcoupling area 2, based on the beam splitting and pupil expansion effect of the light, a small-caliber optical machine can be introduced at the position of the coupling-in area 2, so as to achieve a large eyebox range. Among them, the volume and weight of the optical machine can be reduced, which is conducive to the compactness and lightweight of AR products.

[0051] In some examples of this application, see Figure 1 The light splitting element 3 includes at least one layer of semi-reflective and semi-transparent film, and the light splitting element 3 is horizontally arranged in the substrate 4.

[0052] According to the above example, a semi-reflective and semi-transparent film is introduced into the substrate 4. The semi-reflective and semi-transparent film itself is very thin and light, which will not increase the thickness and weight of the substrate 4, nor will it increase the production cost of the light guide device too much.

[0053] It should be noted that the semi-reflective and semi-transparent membrane introduced in the substrate 4 should be arranged horizontally, that is, perpendicular to the thickness direction of the substrate 4, or parallel to the surface of the substrate 4, so as not to cause the deflection of the propagation direction of the light, and to ensure that the light can be smoothly propagated to the coupling-out area 2 for coupling-out after beam splitting and pupil expansion by the beam splitting element 3.

[0054] See also Figure 1 In the outcoupling area 2, the human eye 01 is within a certain eyebox range, and the outcoupled light distribution is relatively uniform, which can improve the quality of the picture.

[0055] In some examples of this application, see Figure 1 The light splitting element 3 may be a single-layer semi-reflective semi-transmissive membrane. In the thickness direction r2 of the substrate 4, the substrate 4 is divided into two layers by the single-layer semi-reflective semi-transmissive membrane, and the thicknesses of the two layers are d 1 and d 2 The position of the light splitting element 3 in the substrate 4 satisfies the relationship: 2d min tanθ>R IC ; where d min is d 1 and d 2 θ is the angle between the propagation direction r1 of the light coupled into the substrate 4 through the coupling region 1 and the thickness direction r2 of the substrate 4, R IC The aperture of the optical machine.

[0056] In order to achieve the out-coupling image within the eyebox, the distance of each pupil expansion should be smaller than the aperture of the external optical machine. The pupil expansion distance described here can be defined as the distance 2dtanθ of the total internal reflection along the surface of the substrate 4, and the aperture of the coupling region 1 or the optical machine can be defined as R IC, that is, it should satisfy: 2dtanθ<R IC . However, under this scheme, a back coupling effect will occur at the outcoupling area. Specifically, after a part of the light is coupled into the light-guiding device through the coupling-in area, it will encounter the coupling-in area again after two total internal reflections and be directly coupled out, resulting in a large waste of light energy, which directly leads to low coupling efficiency. This is the key issue that restricts the coupling efficiency of light-guiding devices.

[0057] From another perspective, the above solution can increase the thickness d of the substrate of the light guide device, or reduce the aperture R of the coupling region (or optical machine). IC , in order to avoid the back reflection effect, thereby improving the coupling efficiency of the light guide device coupling zone, but it will also lead to uneven coupling of light in the coupling zone, see Figure 2 For example, in the eyebox, some areas have no light outcoupling, while some areas gather light. It can be seen that there is a contradiction between coupling efficiency and outcoupling uniformity.

[0058] According to the above example of this application, when 2d is satisfied min tanθ>R IC Under this condition, a layer of semi-reflective and semi-transparent film is embedded in the appropriate position of the substrate 4. This design can avoid the back reflection effect and increase the coupling efficiency. Due to the presence of the semi-reflective and semi-transparent film, the light is split and expanded at the semi-transparent and semi-reflective film at the same time as it is split and expanded at the out-coupling area, thus avoiding the problem of uneven out-coupling. At the same time, it achieves the balance between high coupling efficiency and high out-coupling uniformity of the light guide device.

[0059] See also Figure 1 For the spatial position of the light splitting element 3 in the substrate 4, when the light splitting element 3 is a single-layer semi-reflective semi-transparent membrane in the above example, the position of the semi-reflective semi-transparent membrane should satisfy 2d min tanθ>R IC ; where d min is d 1 and d 2 The minimum value of .

[0060] As a preferred example, the single-layer semi-reflective and semi-transmissive membrane may be located in the middle of the substrate 4 where the outcoupling region is located. min =d 1 =d 2 , at this time, the beam expansion will be more uniform.

[0061] In some examples of the present application, the light splitting element 3 includes N layers of semi-reflective and semi-transparent films, and N ≥ 2. In the thickness direction r2 of the substrate 4, the substrate 4 is divided into N+1 layers by the multiple layers of the semi-reflective and semi-transparent films, and the thicknesses are d 1 , d 2 , d 3 ……d N+1 The position of the light splitting element 3 in the substrate 4 satisfies: 2d min tanθ>R IC ; where d min is d 1 , d 2 , d 3 ……d N+1 θ is the angle between the propagation direction r1 of the light coupled into the substrate 4 through the coupling region 1 and the thickness direction r2 of the substrate 4, R IC is the aperture of outcoupling zone 1.

[0062] As an optional solution of the present application, a light splitting element 3 composed of two or more layers of semi-reflective and semi-transparent films may also be provided in the substrate 4 at the lower side of the outcoupling region 2. That is, the introduced light splitting element 3 includes but is not limited to a single layer of semi-reflective and semi-transparent film.

[0063] The light splitting element 3 is designed with a multi-layer semi-reflective and semi-transparent film, which can increase the number of beam splitting and pupil expansion and improve the outcoupling uniformity of the outcoupling area.

[0064] It should be noted that the R mentioned in the above two examples IC It is the aperture of the outcoupling zone 1, but it is also related to the aperture of the external optical machine. It can be the smallest one between the aperture of the outcoupling zone 1 and the aperture of the optical machine.

[0065] According to the above two examples, the optical architecture of the light guide device of the present application can improve the coupling-in efficiency of the light guide device and improve the coupling-out uniformity of the coupling-out zone.

[0066] In some examples of this application, see Figure 1 In the thickness direction r2 of the substrate 4, the light splitting element 3 and the outcoupling region 2 are partially arranged opposite to each other.

[0067] The thickness direction r2 is perpendicular to the two opposite surfaces of the substrate 4. For example, the upper and lower surfaces of the substrate 4, see Figure 1 .

[0068] See also Figure 1, the beam splitter element 3 is horizontally embedded in the substrate 4, and the outcoupling area 2 is horizontally located on the upper surface of the substrate 4, and the two are arranged in parallel, but the beam splitter element 3 and the outcoupling area 2 are not completely opposite, and the projection of the beam splitter element 3 on the upper surface of the substrate 4 does not completely cover the outcoupling area 2, and the two are misaligned. The purpose of this design is to allow the light propagating in the substrate 4 to pass through the beam splitter element 3 as much as possible, and to avoid part of the light being wasted by total reflection propagation only between the beam splitter element 3 and the substrate 4.

[0069] The area of ​​the light splitting element 3 is comparable to the area of ​​the outcoupling region 2 .

[0070] Specifically, see Figure 1 The light input end A1 of the beam splitter element 3 extends to the outside of the light input end A2 of the outcoupling area 2 , and the light transmission end B2 of the outcoupling area 2 extends to the outside of the light transmission end B1 of the beam splitter element 3 .

[0071] Optionally, along the setting direction of the beam splitter element 3, a target interval is formed between the light transmission end B1 of the beam splitter element 3 and the light transmission end B2 of the outcoupling region 2, and the target interval is no greater than 4 mm.

[0072] According to the above example, the area of ​​the light splitting element 3 is equivalent to the area of ​​the outcoupling region 2, see Figure 1 For the light splitting element 3, the right side is the light transmission end B1 (or Figure 1 The right side of the beam splitter element 3 should not exceed the right side of the outcoupling zone 2 as much as possible. The right side of the outcoupling zone 2 is the light transmission end B2 of the outcoupling zone 2. The horizontal rear end difference between the light transmission end B1 of the beam splitter element 3 and the light transmission end B2 of the outcoupling zone 2, i.e., the target interval mentioned above, should be designed to be no more than 4 mm. This setting can effectively prevent a part of the light from being wasted due to total reflection propagation only between the beam splitter element 3 and the substrate 4, thereby improving the light utilization rate.

[0073] In some examples of the present application, the light splitting element 3 may be a semi-reflective and semi-transparent film with a gradually changing transmittance.

[0074] That is to say, one or more semi-transparent and semi-reflective films forming the light splitting element 3 can also be set in a pattern with gradually changing transmittance. This design can be coordinated with the grating parameter design of the outcoupling region 2, which is conducive to further improving the outcoupling uniformity.

[0075] In some examples of the present application, the light-guiding device may further include a turning grating, which is located on the total reflection light path between the coupling-in region 1 and the coupling-out region 2, and is used to receive light from the coupling-in region 1 and turn the light to propagate to the coupling-out region 2.

[0076] Wherein, the turning grating may be a one-dimensional grating.

[0077] In some examples of the present application, the coupling-in region 1 includes a one-dimensional grating, and the coupling-out region 2 includes a one-dimensional grating or a two-dimensional grating.

[0078] The outcoupling region 2 may directly use a two-dimensional grating, or a combination of at least two one-dimensional gratings.

[0079] In the present application, for the one-dimensional grating, one or more of a surface relief grating and a holographic volume grating can be used. The surface relief grating includes a rectangular grating, a blazed grating, a tilted grating, a step grating, a sinusoidal grating, etc. The holographic volume grating includes a photopolymer volume grating, a polymer dispersed liquid crystal volume grating, a liquid crystal volume grating, etc.

[0080] In the present application, for the two-dimensional grating, a surface relief grating may be used, and specific types include but are not limited to parallelogram gratings, prism gratings, and double prism gratings.

[0081] It should be noted that in order to obtain better optical performance, in the light-guiding device provided in the embodiment of the present application, the grating in each functional area can be zoned and designed based on parameters such as grating thickness, duty cycle, grating tilt angle, coating depth, coating material, volume grating Bragg tilt angle and refractive index of volume grating material.

[0082] In some examples of the present application, the light guiding device is a diffractive light waveguide.

[0083] According to another embodiment of the present application, a head mounted display device is provided, wherein the head mounted display device comprises a housing, an optical engine, and the light guide device as described above.

[0084] The AR head-mounted display device is in the form of, for example, AR glasses or an AR helmet, etc. The specific form of the head-mounted display device is not limited in the embodiments of the present application.

[0085] The shell is, for example, a frame of glasses or a frame of a helmet.

[0086] The optical machine is opposite to the coupling-in area 1 of the light-guiding device, or the light projected by the optical machine can be incident on the coupling-in area 1 .

[0087] The specific implementation of the head-mounted display device provided in the embodiment of the present application can refer to the various embodiments of the above-mentioned 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: The invention comprises a substrate (4) and an incoupling region (1) and an outcoupling region (2) arranged on the substrate (4); a light splitting element (3) is embedded on one side of the substrate (4) close to the outcoupling region (2); and the light splitting element (3) is located on a total reflection optical path from the incoupling region (1) to the outcoupling region (2); The coupling-in region (1) is used to couple light into the substrate (4) and allow the light to propagate by total reflection in the substrate (4); The light splitting element (3) is used to perform at least one beam splitting and pupil expansion on the light propagating through the coupling-in area (1); The outcoupling area (2) is used to couple out the light passing through the light splitting element (3) after beam splitting and pupil expansion.

2. The light guide device according to claim 1, characterized in that: The light splitting element (3) comprises at least one layer of semi-reflective and semi-transmissive film, and the light splitting element (3) is horizontally arranged in the substrate (4).

3. The light guide device according to claim 2, characterized in that: The light splitting element (3) is a single-layer semi-reflective and semi-transmissive membrane, and in the thickness direction r2 of the substrate (4), the substrate (4) is divided into two layers by the single-layer semi-reflective and semi-transmissive membrane, and the thicknesses are d1 and d2 respectively; The position of the light splitting element (3) in the substrate (4) satisfies: 2d min tanθ>R IC ; Among them, d min is the minimum value of d1 and d2, θ is the angle between the propagation direction r1 of the light coupled into the substrate (4) through the coupling region (1) and the thickness direction r2 of the substrate (4), R IC is the diameter of the coupling zone (1).

4. The light guide device according to claim 2, characterized in that: The light splitting element (3) comprises N layers of semi-reflective and semi-transparent films stacked together, where N is greater than or equal to 2. In the thickness direction r2 of the substrate (4), the substrate (4) is divided into N+1 layers by the multiple layers of the semi-reflective and semi-transparent films, and the thicknesses are d1, d2, d3, ..., d N+1 ; The position of the light splitting element (3) in the substrate (4) satisfies: 2d min tanθ>R IC ; Among them, d min is d1, d2, d3...d N+1 θ is the angle between the propagation direction r1 of the light coupled into the substrate (4) through the coupling region (1) and the thickness direction r2 of the substrate (4), R IC is the diameter of the coupling zone (1).

5. The light guide device according to any one of claims 1 to 4, characterized in that: In the thickness direction r2 of the substrate (4), the light splitting element (3) and the outcoupling region (2) are partially arranged opposite to each other.

6. The light guide device according to claim 5, characterized in that: The light input end A1 of the light splitting element (3) extends to the outside of the light input end A2 of the outcoupling region (2), and the light transmission end B2 of the outcoupling region (2) extends to the outside of the light transmission end B1 of the light splitting element (3).

7. The light guide device according to claim 6, characterized in that: Along the setting direction of the light splitting element (3), a target interval is formed between the light transmission end B1 of the light splitting element (3) and the light transmission end B2 of the outcoupling region (2), and the target interval is no greater than 4 mm.

8. The light guide device according to claim 7, characterized in that: The light splitting element (3) is a semi-reflective and semi-transparent membrane with a gradually changing transmittance.

9. The light guide device according to claim 7, characterized in that: The light-guiding device further comprises a turning grating, which is located on the total reflection light path between the coupling-in region (1) and the coupling-out region (2), and is used for receiving light from the coupling-in region (1) and redirecting the light to propagate to the coupling-out region (2).

10. The light guide device according to claim 7, characterized in that: The coupling-in region (1) comprises a one-dimensional grating, and the coupling-out region (2) comprises a one-dimensional grating or a two-dimensional grating.

11. The light guide device according to claim 1, characterized in that: The light guiding device is an optical waveguide element.

12. A head mounted display device, characterized in that: include: shell; Optical machine; and A light guiding device as claimed in any one of claims 1 to 11.

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