Augmented reality heads-up display device and vehicle

Abstract

The application relates to an augmented reality head-up display device, which comprises an image unit, a light waveguide unit and a reflection unit, the image unit is used for generating image light and guiding the image light to be incident on the surface of the light waveguide unit, the light waveguide unit conducts the image light and emits the image light towards the reflection unit, the reflection unit reflects the image light to the human eye and generates a virtual image, the light waveguide unit comprises a light waveguide layer and first and second light shielding layers arranged on the two sides of the light waveguide layer, the first light shielding layer is used for absorbing the light transmitted from the light waveguide layer, the second light shielding layer is used for absorbing the light transmitted and / or reflected from the light waveguide layer and the sunlight transmitted from the outside, so that stray light interference is eliminated, the quality of the reflection of the image light to the human eye and the generation of the virtual image by the reflection unit is improved, the augmented reality head-up display device has the performances of large field of view, small size, long virtual image distance and simple structure, is suitable for most windshields and has high mass production universality.

Description

TECHNICAL FIELD

[0001] The application relates to an augmented reality head-up display device and a vehicle, and belongs to the technical field of display equipment. BACKGROUND

[0002] A head-up display (HUD) functions as a "projector" of automobile information. The technology can project automobile-related information in front of the driver's line of sight, thereby reducing the frequency of looking down at the instrument panel or the central control screen during driving. A traditional HUD is an opto-mechanical coupling component mainly composed of a master control PCB board, a light source, a display medium, an optical lens group, a direct current motor, and the like. Information is reflected onto a transparent medium (a display screen or a windshield) through multiple mirror surface reflections of the display light source, so that a virtual image appears to be suspended in front of the human eye.

[0003] According to product forms, the current mainstream HUDs are mainly divided into combined types (C-HUD) and windshield types (W-HUD). Technically, the optical structure of the C-HUD is simple, and the design is relatively easy, but the display size and the projection distance are limited, and the C-HUD may cause secondary damage to the driver in the event of a vehicle collision. The W-HUD has a more integrated display effect, but the optical structure is complex, the design and arrangement are difficult, the volume is large, and the optical principle needs to be matched with a complex windshield, which undoubtedly increases the difficulty of preparation and mass production. Please refer to Figure 1 , a light path schematic diagram of a traditional W-HUD scheme, in which image light rays of different field angles are reflected multiple times through a free-form surface and reflected to the human eye through the windshield. In order to meet the imaging design, the scheme needs a large geometric space volume, and the distance of the virtual image is not far enough, the eyebox space is small, and the sunlight may flow back to cause device heating, affecting the quality.

[0004] In recent years, the augmented reality head-up display (AR-HUD) has emerged, which superimposes digital images on the real environment outside the vehicle, so that the driver obtains the visual effect of augmented reality, which can be used for AR navigation, adaptive cruise control, lane departure warning, and the like.

[0005] Compared with the current mainstream C-HUD and W-HUD, the AR-HUD has the characteristics of small volume, long projection distance, large field of view, and high universality. The augmented reality (AR) uses a diffraction structure unit to control the light path, and in an ideal case, the diffraction structure unit only diffracts the light to the human eye. However, the light will be transmitted out of the optical waveguide, and the light will also be reflected from the surface of the optical waveguide, which will affect the quality of the virtual image formed. SUMMARY

[0006] The purpose of the present application is to provide an augmented reality head-up display device with high imaging quality, simple structure and small volume.

[0007] To achieve the above object, the present application provides the following technical solutions: An augmented reality head-up display device, comprising an image unit, a light waveguide unit and a reflection unit, the image unit is used to generate image light and guide the image light to be incident on the surface of the light waveguide unit, the light waveguide unit conducts the image light and emits it towards the reflection unit, the reflection unit reflects the image light to the human eye and generates a virtual image, the light waveguide unit comprises a light waveguide layer, a first light shielding layer arranged on one side of the light waveguide layer and a second light shielding layer arranged on the other side of the light waveguide layer, the first light shielding layer is used to absorb the light transmitted from the light waveguide layer, and the second light shielding layer is used to absorb the light transmitted and / or reflected from the light waveguide layer and the sunlight transmitted from the outside.

[0008] Further, the first light shielding layer and the second light shielding layer have a gap between the light waveguide layer.

[0009] Further, the absorption rate of the first light shielding layer and the second light shielding layer to the visible light waveband is greater than 60%.

[0010] Further, the light waveguide layer comprises at least one light waveguide.

[0011] Further, the light waveguide surface is provided with a coupling-in area and a coupling-out area, the coupling-in area is configured to make the incident image light be coupled into the light waveguide and be conducted along the light waveguide to the coupling-out area, and the coupling-out area is configured to emit the image light in the waveguide.

[0012] Further, the projection area of the first light shielding layer on the surface of the light waveguide layer covers the projection area of the coupling-in area on the surface of the light waveguide layer, and the projection area of the first light shielding layer on the surface of the light waveguide layer and the projection area of the coupling-out area on the surface of the light waveguide layer are arranged separately.

[0013] Further, the projection area of the second light shielding layer on the surface of the light waveguide layer covers the projection area of the coupling-out area on the surface of the light waveguide layer, and the projection area of the second light shielding layer on the surface of the light waveguide layer and the projection area of the image unit on the surface of the light waveguide layer are arranged separately.

[0014] Further, the coupling-in area and the coupling-out area are periodic grating structures.

[0015] Further, the light waveguide layer comprises a first light waveguide and a second light waveguide, a bonding layer is arranged between the first light waveguide and the second light waveguide, the first light waveguide is used to modulate blue and green waveband light, and the second light waveguide is used to modulate green and red waveband light.

[0016] The present invention also provides a vehicle including the augmented reality head-up display device as described above.

[0017] The beneficial effects of the present invention are as follows: The augmented reality head-up display device of the present invention eliminates stray light interference by setting a first light-shielding layer on one side of the optical waveguide layer to absorb the light transmitted from the optical waveguide layer, and setting a second light-shielding layer on the other side of the optical waveguide layer to absorb the light transmitted and / or reflected from the optical waveguide layer as well as the sunlight transmitted from the outside. This improves the quality of the image light reflected by the reflection unit to the human eye and the generation of the virtual image. The augmented reality head-up display device has the performance of large field of view, small size, long virtual image distance, and simple structure. At the same time, it is suitable for most windshields and has high mass production versatility.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the optical path of a traditional W-HUD solution in the existing technology;

[0020] Figure 2 This is a schematic diagram of the optical path of an augmented reality head-up display device according to an embodiment of this application;

[0021] Figure 3 for Figure 2 The schematic diagram of the optical waveguide shown is shown below;

[0022] Figure 4 for Figure 2 A schematic diagram of a portion of the optical path of an augmented reality head-up display device without a first light-shielding layer, as shown in the figure.

[0023] Figure 5 for Figure 2 A schematic diagram of a portion of the optical path of the augmented reality head-up display device with a first light-shielding layer shown in the figure;

[0024] Figure 6 for Figure 2 A schematic diagram of part of the optical path of the augmented reality head-up display device without a second light-shielding layer shown in the figure;

[0025] Figure 7 for Figure 2 A schematic diagram of a portion of the optical path of the augmented reality head-up display device with a second light-shielding layer shown in the figure;

[0026] Figure 8 for Figure 2 The schematic diagram of the optical path of the monolithic waveguide shown in the figure;

[0027] Figure 9 For Figure 2 A double-chip double-channel optical waveguide optical path schematic diagram shown in Figure 1.

[0028] Figure 10 A graph showing the relationship between the absorption, reflection and transmission efficiency of the optical waveguide to the image light and the wavelength. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated mechanisms or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0032] Please refer to Figure 2 , the augmented reality head-up display device shown in an embodiment of the present application comprises an image unit 1, an optical waveguide unit 2 and a reflection unit 3. The image unit 1 is used to generate image light and guide the image light to be incident on the surface of the optical waveguide unit 2. The optical waveguide unit 2 conducts the image light while increasing the exit pupil expansion and emits it towards the reflection unit 3. The image light emitted by the optical waveguide unit 2 is irradiated onto the reflection unit 3, and the reflection unit 3 reflects the image light irradiated thereon to the human eye and generates a virtual image.

[0033] The principle of head-up display of the augmented reality head-up display device is that the image unit 1 emits image light of a certain field of view angle, the image light is incident on the optical waveguide unit 2, is emitted after the exit pupil expansion of the optical waveguide unit 2, and the emitted image light is reflected to the human eye at a certain reflection angle by the reflection unit 3, so that the human eye can see a virtual image at a certain projection distance through the reflection unit 3.

[0034] The optical waveguide unit 2 comprises an optical waveguide layer 21, a first light shielding layer 22 arranged on one side of the optical waveguide layer 21 and a second light shielding layer 23 arranged on the other side of the optical waveguide layer 21, the first light shielding layer 22 is used to absorb light transmitted from the optical waveguide layer 21, and the second light shielding layer 23 is used to absorb light transmitted and / or reflected from the optical waveguide layer 21 and sunlight transmitted from the outside.

[0035] The first light shielding layer 22 and the second light shielding layer 23 have a gap between the optical waveguide layer 21, so as to absorb the light transmitted or reflected from the optical waveguide layer 21, and avoid absorbing the light in the optical waveguide layer 21. The specific gap is not specifically limited here, and can be set according to actual needs.

[0036] The absorption rate of the first light shielding layer 22 and the second light shielding layer 23 to the visible light band is greater than 60%, that is, the first light shielding layer 22 and the second light shielding layer 23 can be a structure with an absorption rate to the visible light band greater than 60% or a material with an absorption rate to the visible light band greater than 60%, and specific materials and structures are not listed one by one here, and can be selected according to actual needs.

[0037] Please refer to Figure 3 The optical waveguide layer 21 comprises at least one optical waveguide 211, which can be one optical waveguide 211, two optical waveguides 211 or three optical waveguides 211, etc. The surface of the optical waveguide 211 is provided with a coupling-in area 212 and a coupling-out area 213, the coupling-in area 212 is configured to couple the incident image light into the optical waveguide 211 and conduct the image light along the optical waveguide 211 to the coupling-out area 213, and the coupling-out area 213 is configured to emit the image light in the optical waveguide 211. The image light passes through the coupling-in area 212, and diffraction and total reflection occur inside the optical waveguide 211, the diffraction and total reflection of the image light passes through the optical waveguide 211 multiple times, the image light fills the entire coupling-out area 213 and is emitted from the coupling-out area 213, thereby realizing pupil expansion. The optical waveguide 211 can continuously conduct the coupled light in a specific direction under the condition of satisfying total reflection, the transmittance of the optical waveguide 211 is greater than 80%, and the optical waveguide 211 can be glass, resin or a material with a transmittance greater than 80% under visible light, which is not listed one by one here. The thickness of the optical waveguide 211 is less than 2mm, and the specific thickness of the optical waveguide 211 is not specifically limited here and can be set according to actual needs.

[0038] The coupling-in region 212 and the coupling-out region 213 are structural units with diffraction characteristics, and are essentially nanostructures with refractive index gradients and capable of realizing light diffraction transmission. Specifically, the coupling-in region 212 and the coupling-out region 213 are both periodic grating structures, such as nanoscale relief gratings or volume holographic gratings. The periodic grating structure can be directly fabricated on the optical waveguide 211, or can be fabricated on a film in advance, and then the film carrying the grating structure is combined with the optical waveguide 211. The bottom of the grating structure forming the coupling-in region 212 and the coupling-out region 213 can be located on the surface of the optical waveguide 211 or inside the optical waveguide 211.

[0039] The coupling-in region 212 and the coupling-out region 213 can both be rectangular, or the coupling-in region 212 can also be circular or other shapes, as needed. The coupling-in region 212 and the coupling-out region 213 are arranged on the same side of the same face or on the two sides of different faces of the optical waveguide 211 along the same axis. In this embodiment, the coupling-in region 212 and the coupling-out region 213 are located on the same surface of the optical waveguide 211 and have a spacing therebetween. The grating structure can be prepared by holographic interference technology, photolithography technology or nanoimprint technology, and can be freely selected according to actual needs.

[0040] The coupling-in region 212 is preferably an inclined relief grating. The image light is incident at the position of the coupling-in region 212 and is coupled into the optical waveguide 211 through the diffraction process. The inclined diffraction grating is selective to wavelength and avoids dispersion, and has a high diffraction efficiency for a certain wavelength band. The grating structure of the coupling-out region 213 has the same period and orientation as the grating of the coupling-in region 212, and can be a positive grating or an inclined grating.

[0041] By designing the period, depth, duty cycle and inclination angle of the grating structure, light of a specific wavelength or wavelength band is efficiently selected, realizing the wavelength selective function. For example, the green image light is coupled and then bent and transmitted in the waveguide, and the blue and red image light is not affected, realizing single-channel light diffraction. Or the blue and red wavelength band light is efficiently selected, realizing double-channel light diffraction. The single-channel diffraction optical waveguide 211 only transmits image light of a certain color, and the image light of other colors passes through the optical waveguide 211, realizing that the light does not interfere with each other.

[0042] In addition, the surface of the optical waveguide 211 can also be provided with a turning region (not shown). The turning region is used to change the propagation direction of the image light in the optical waveguide 211. When the image light is incident on the coupling-in region 212, the image light is totally reflected to the turning region in the optical waveguide 211. The turning region changes the propagation direction of the image light, and the image light after changing the direction is totally reflected to the coupling-out region 213. The output image can be effectively expanded, thereby expanding the viewing angle range and better meeting the user's needs.

[0043] Please refer to Figure 4 and Figure 5 If the first light shielding layer 22 is not provided, the image light conducted in the optical waveguide layer 21 will still have part of the image light transmitted out of the optical waveguide 211 even after passing through the multiple optical waveguides 211. In particular, whether the image light is perpendicular or oblique to the coupling-in region 212, only part of the light will be diffracted and conducted in the optical waveguide 211, and the 0th order diffracted light will be transmitted out of the optical waveguide 211. This part of the image light will be reflected by any surface with reflection characteristics or diffuse reflection. The light after reflection or diffuse reflection will be incident into the optical waveguide 211 again, introducing stray light and affecting the imaging quality. Please refer to Figure 10 In the visible light band, part of the image light will be transmitted out of the optical waveguide 211 from the side opposite to the coupling-in region 212 after the image light enters the optical waveguide 211 from the coupling-in region 212. Among them, with the increase of the wavelength of the image light, the reflection efficiency of the optical waveguide 211 to the image light gradually decreases, the transmission efficiency gradually increases, and the absorption efficiency is always close to 0. If the first light shielding layer 22 is provided, the first light shielding layer 22 will absorb the image light transmitted out of the optical waveguide 211, avoiding the image light after reflection or diffuse reflection to be incident into the optical waveguide 211 again, and improving the imaging quality.

[0044] The first light shielding layer 22 and the coupling-in region (not shown) are oppositely arranged on both sides of the optical waveguide 211. The projection area of the first light shielding layer 22 on the surface of the optical waveguide layer 21 covers the projection area of the coupling-in region on the surface of the optical waveguide layer 21, and the projection area of the first light shielding layer 22 on the surface of the optical waveguide layer 21 is arranged separately from the projection area of the coupling-out region (not shown) on the surface of the optical waveguide layer 21, thereby maximizing the absorption of light transmitted out of the surface of the optical waveguide layer 21. That is, the maximum range of the projection area of the first light shielding layer 22 on the surface of the optical waveguide layer 21 is the area other than the projection area of the coupling-out region on the surface of the optical waveguide layer 21, and the minimum range is the projection area of the coupling-in region on the surface of the optical waveguide layer 21.

[0045] Please refer to Figure 6 and Figure 7, if the second light shielding layer 23 is not provided, the image light conducted in the light waveguide layer 21 will be transmitted out of the light waveguide 211 from the side opposite to the reflecting unit 3 at the coupling-out area 213, and the sunlight from the outside will also be transmitted out of the light waveguide 211 from the side opposite to the reflecting unit 3 at the coupling-out area 213 after being reflected by the reflecting unit 3. Meanwhile, when the image light is incident on the light waveguide 211, part of the light will be reflected by the surface of the light waveguide 211. These light will be reflected or diffused by any surface with reflecting properties, and then be incident on the light waveguide 211 again, which will introduce stray light and affect the imaging quality. If the light waveguide unit 2 is provided with the second light shielding layer 23, the second light shielding layer 23 will absorb these light, so that the light will not be reflected or diffused again and then be incident on the light waveguide 211, thereby improving the imaging quality.

[0046] The second light shielding layer 23 and the coupling-out area (not shown) are arranged on both sides of the light waveguide 211. The projection area of the second light shielding layer 23 on the surface of the light waveguide layer 21 covers the projection area of the coupling-out area on the surface of the light waveguide layer 21, and the projection area of the second light shielding layer 23 on the surface of the light waveguide layer 21 is arranged separately from the projection area of the image unit 1 on the surface of the light waveguide layer 21, so as to maximize the absorption of the light transmitted out of or / and reflected by the surface of the light waveguide layer 21. That is, the maximum range covered by the projection area of the second light shielding layer 23 on the surface of the light waveguide layer 21 is the area other than the projection area of the image unit 1 on the surface of the light waveguide layer 21, and the minimum range is the projection area of the coupling-out area on the surface of the light waveguide layer 21.

[0047] By adjusting the size of the grating structure of the coupling-in area 212 and the coupling-out area 213, the distance between the two, the specific structure of the grating, the thickness of the light waveguide 211, and the position and size of the first light shielding layer 22 and the second light shielding layer 23, the image light can be diffracted and coupled in through the coupling-in area 212, the light can be diffracted and transmitted to the coupling-out area 213 through the light waveguide 211, the light transmitted out of and reflected by the surface of the light waveguide 211 can be absorbed by the first light shielding layer 22 or the second light shielding layer 23, and then be emitted from the coupling-out area 213 and irradiated to the reflecting unit 3, and the light can be reflected by the reflecting unit 3 to the human eye, thereby forming a virtual image of the image in front of the human eye.

[0048] Please refer to Figure 8 The light waveguide layer 21 comprises a single light waveguide 211, and the surface of the light waveguide 211 is provided with a coupling-in area 212 and a coupling-out area 213. The single light waveguide 211 is a color light waveguide lens used for realizing color augmented reality display. The red, green and blue image light is incident on the single light waveguide 211, each color image light is diffracted and bent through the coupling-in area 212, and then is emitted from the coupling-out area 213. The light is emitted from the color waveguide lens to realize color augmented reality display.

[0049] Please refer to Figure 9 The light waveguide layer 21 comprises two pieces of double-channel light waveguides, specifically a first light waveguide 214 and a second light waveguide 215, and an adhesive layer 216 is arranged between the first light waveguide 214 and the second light waveguide 215, the first light waveguide 214 is used for modulating blue and green band light, and the second light waveguide 215 is used for green and red band light. By combining two pieces of double-channel light waveguides, red, green and blue three-color light modulation is realized, and a color enhanced reality display effect is achieved.

[0050] Please refer to Figure 2 The light waveguide layer 21 comprises three pieces of light waveguides 211, which respectively regulate and control one of red, green and blue colors, and regulate and control different colors, realize red, green and blue three-color light modulation, and achieve a color enhanced reality display effect. The specific number of light waveguides 211 and the color they regulate are not specifically limited here and can be set according to actual needs, and are not listed one by one here.

[0051] The application also provides a vehicle comprising the enhanced reality head-up display device as shown above, which forms a virtual image in front of the windshield. The vehicle can be a bicycle, an electric vehicle, etc., such as a pure electric vehicle, a range-extended electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a new energy vehicle, etc., without specific limitation.

[0052] In summary, the enhanced reality head-up display device shown in the application eliminates stray light interference by arranging a first light shielding layer on one side of the light waveguide layer to absorb light transmitted from the light waveguide layer, arranging a second light shielding layer on the other side of the light waveguide layer to absorb light transmitted and / or reflected from the light waveguide layer and sunlight transmitted from the outside, thereby improving the quality of the image light reflected to the human eye by the reflection unit and producing a virtual image. The enhanced reality head-up display device has the performance of large field of view, small size, far virtual image distance, simple structure, and is suitable for most windshields, and has high mass production universality.

[0053] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present disclosure.

[0054] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. An augmented reality head-up display device, characterized by comprising: The device comprises an image unit, a light waveguide unit and a reflection unit, the image unit is used to generate image light and direct the image light to the surface of the light waveguide unit, the light waveguide unit conducts the image light and emits it towards the reflection unit, the reflection unit reflects the image light to the human eye and generates a virtual image, the light waveguide unit comprises a light waveguide layer, a first light shielding layer arranged on one side of the light waveguide layer and a second light shielding layer arranged on the other side of the light waveguide layer, the first light shielding layer is used to absorb the light transmitted from the light waveguide layer, and the second light shielding layer is used to absorb the light transmitted and / or reflected from the light waveguide layer and the sunlight transmitted from the outside.

2. The augmented reality head-up display device of claim 1, wherein, The first light shielding layer and the second light shielding layer have a gap between the light waveguide layer.

3. The augmented reality head-up display device of claim 1, wherein, The absorption rate of the first light shielding layer and the second light shielding layer to the visible light waveband is greater than 60%.

4. The augmented reality head-up display device of claim 1, wherein, The light waveguide layer comprises at least one light waveguide.

5. The augmented reality head-up display device of claim 4, wherein, The light waveguide surface is provided with a coupling-in area and a coupling-out area, the coupling-in area is configured to make the incident image light coupled into the light waveguide and conducted along the light waveguide to the coupling-out area, and the coupling-out area is configured to emit the image light in the waveguide.

6. The augmented reality head-up display device of claim 5, wherein, The projection area of the first light shielding layer on the surface of the light waveguide layer covers the projection area of the coupling-in area on the surface of the light waveguide layer, and the projection area of the first light shielding layer on the surface of the light waveguide layer and the projection area of the coupling-out area on the surface of the light waveguide layer are arranged separately.

7. The augmented reality head-up display device of claim 5, wherein, The projection area of the second light shielding layer on the surface of the light waveguide layer covers the projection area of the coupling-out area on the surface of the light waveguide layer, and the projection area of the second light shielding layer on the surface of the light waveguide layer and the projection area of the image unit on the surface of the light waveguide layer are arranged separately.

8. The augmented reality head-up display device of claim 5, wherein, The coupling-in area and the coupling-out area are periodic grating structures.

9. The augmented reality head-up display device of claim 1, wherein, The light waveguide layer comprises a first light waveguide and a second light waveguide, a bonding layer is arranged between the first light waveguide and the second light waveguide, the first light waveguide is used to modulate blue and green waveband light, and the second light waveguide is used to modulate green and red waveband light.

10. A vehicle characterized by comprising: The device comprises an image unit, a light waveguide unit and a reflection unit, the image unit is used to generate image light and direct the image light to the surface of the light waveguide unit, the light waveguide unit conducts the image light and emits it towards the reflection unit, the reflection unit reflects the image light to the human eye and generates a virtual image, the light waveguide unit comprises a light waveguide layer, a first light shielding layer arranged on one side of the light waveguide layer and a second light shielding layer arranged on the other side of the light waveguide layer, the first light shielding layer is used to absorb the light transmitted from the light waveguide layer, and the second light shielding layer is used to absorb the light transmitted and / or reflected from the light waveguide layer and the sunlight transmitted from the outside. The first light shielding layer and the second light shielding layer have a gap between the light waveguide layer. The absorption rate of the first light shielding layer and the second light shielding layer to the visible light waveband is greater than 60%. The light waveguide layer comprises at least one light waveguide. The light waveguide surface is provided with a coupling-in area and a coupling-out area, the coupling-in area is configured to make the incident image light coupled into the light waveguide and conducted along the light waveguide to the coupling-out area, and the coupling-out area is configured to emit the image light in the waveguide. The projection area of the first light shielding layer on the surface of the light waveguide layer covers the projection area of the coupling-in area on the surface of the light waveguide layer, and the projection area of the first light shielding layer on the surface of the light waveguide layer and the projection area of the coupling-out area on the surface of the light waveguide layer are arranged separately. The projection area of the second light shielding layer on the surface of the light waveguide layer covers the projection area of the coupling-out area on the surface of the light waveguide layer, and the projection area of the second light shielding layer on the surface of the light waveguide layer and the projection area of the image unit on the surface of the light waveguide layer are arranged separately. The coupling-in area and the coupling-out area are periodic grating structures. The light waveguide layer comprises a first light waveguide and a second light waveguide, a bonding layer is arranged between the first light waveguide and the second light waveguide, the first light waveguide is used to modulate blue and green waveband light, and the second light waveguide is used to modulate green and red waveband light. The device comprises an image unit, a light waveguide unit and a reflection unit, the image unit is used to generate image light and direct the image light to the surface of the light waveguide unit, the light waveguide unit conducts the image light and emits it towards the reflection unit, the reflection unit reflects the image light to the human eye and generates a virtual image, the light waveguide unit comprises a light waveguide layer, a first light shielding layer arranged on one side of the light waveguide layer and a second light shielding layer arranged on the other side of the light waveguide layer, the first light shielding layer is used to absorb the light transmitted from the light waveguide layer, and the second light shielding layer is used to absorb the light transmitted and / or reflected from the light waveguide layer and the sunlight transmitted from the outside. The first light shielding layer and the second light shielding layer have a gap between the light waveguide layer. The absorption rate of the first light shielding layer and the second light shielding layer to the visible light waveband is greater than 60%. The light waveguide layer comprises at least one light waveguide. The light waveguide surface is provided with a coupling-in area and a coupling-out area, the coupling-in area is configured to make the incident image light coupled into the light waveguide and conducted along the light waveguide to the coupling-out area, and the coupling-out area is configured to emit the image light in the waveguide.

Images