A diffractive optical waveguide display device with reduced light leakage
By setting a matte film on the diffraction optical waveguide of the AR device and utilizing the angle design of the optical machine to reduce light leakage, the problem of light leakage in the exit pupil area is solved, thereby improving user experience and information security.
Patent Information
- Application Number
- CN202211439862.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-17
- Publication Date
- 2025-10-14
- Estimated Expiration
- 2042-11-17
AI Technical Summary
The diffraction light waveguide display device of existing AR equipment has light leakage in the exit pupil area, affecting user experience and information security.
A matte film is set on the diffraction light waveguide. The angle between the central light of the optical machine and the waveguide surface is used to reduce light leakage in the area where the imaging position is not on the center line of sight. The matte film absorbs the light from the external environment.
Effectively reduce light leakage from the exit pupil area to the external environment, improve user experience, and prevent information leakage and external interference.
Smart Images
Figure CN115903240B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of display devices, and in particular to a diffraction light waveguide display device capable of reducing light leakage. Background Art
[0002] Augmented reality (AR) is a technology that integrates the real world and virtual information. AR devices include micro projectors and displays. When using AR devices, the human eye must be able to see both the virtual images displayed by AR and the real external environment through the display.
[0003] Today's AR devices use diffraction waveguides to transmit light, which has become the mainstream solution. Diffraction waveguides are designed to set diffraction gratings on transparent media (such as glass). Light is emitted by the projector, enters the diffraction waveguide from the entrance pupil area, is totally reflected in the diffraction waveguide to the diffraction grating area, and finally reaches the exit pupil area. After being emitted from the exit pupil area, it is transmitted to the human eye; light will be transmitted and reflected in the exit pupil area, and light will be emitted from both sides of the exit pupil area. The light on one side will enter the human eye, and the light on the other side will enter the external environment.
[0004] Light emitted from AR devices leaks into the environment, causing interference to others and leaking displayed information, affecting the user experience. The exit pupil area is the largest light leakage area on the entire diffraction light waveguide, and light leakage in the exit pupil area needs to be reduced to improve the user experience of AR devices. Therefore, in response to this situation, there is an urgent need to develop a diffraction light waveguide display device that reduces light leakage to meet practical needs. Summary of the Invention
[0005] In view of this, the present invention addresses the deficiencies in the prior art, and its main purpose is to provide a diffraction light waveguide display device that reduces light leakage. The central light ray passing through the optical machine forms an angle with the perpendicular line of the waveguide surface, and an extinction film is provided on the diffraction light waveguide at the imaging position which is not on the center line of sight. The phenomenon of light leakage from the exit pupil area to the external environment is reduced, and the extinction film absorbs part of the leaked light, thereby improving the user experience.
[0006] To achieve the above object, the present invention adopts the following technical solutions:
[0007] A diffraction light waveguide display device for reducing light leakage comprises a diffraction light waveguide, an optical engine, and a matte film. The diffraction light waveguide has two opposing waveguide surfaces, at least one of which is provided with a diffraction grating region, the diffraction grating region including an entrance pupil region and at least one exit pupil region. The optical engine is located to the side of the entrance pupil region. The matte film has at least one layer provided on one of the waveguide surfaces and fully covers the exit pupil region. The central ray of the optical engine forms an angle A with a perpendicular line to the waveguide surface.
[0008] As a preferred solution: the light emitted by the optical machine enters the entrance pupil area in the direction of the angle A between the central light and the perpendicular line of the waveguide surface, the grating diffraction light in the entrance pupil area is totally reflected in the diffraction light waveguide and finally reaches the exit pupil area, the light diffracted by the diffraction grating in the exit pupil area is emitted from the two waveguide surface positions corresponding to the exit pupil area of the diffraction light waveguide, the light at the waveguide surface position corresponding to the user's eye side enters the user's eye, and the light at the waveguide surface position corresponding to the external environment side enters the external environment after the light intensity is weakened by the extinction film.
[0009] As a preferred solution: the imaging center light of the user's eye corresponding to the exit pupil area forms an angle A1 with the perpendicular line of the waveguide surface; the imaging center light of the external environment corresponding to the exit pupil area forms an angle A2 with the perpendicular line of the waveguide surface; the values of the angle A, angle A1 and angle A2 are equal.
[0010] As a preferred solution: the field angle of the light emitted by the optical machine is an included angle C, which is 10 degrees to 60 degrees; the above-mentioned included angle A is 5 degrees to 40 degrees.
[0011] As a preferred solution: the matt film is arranged above the waveguide surface, and an air gap is provided between the matt film and the waveguide surface.
[0012] As a preferred solution: the waveguide surface is provided with glass for protection, and the matte film is flatly attached to the side of the glass facing away from the waveguide surface.
[0013] As a preferred solution: the imaging light emitted from the exit pupil area forms a certain angle with the perpendicular line of the waveguide surface, and the transmittance of the matte film to the imaging light decreases as the angle increases.
[0014] As a preferred solution: the optical engine is located beside the waveguide surface on one side of the matte film, and the matte film avoids covering the entrance pupil area.
[0015] As a preferred solution: the optical engine is located beside one of the waveguide surfaces away from the matte film, and the matte film entirely covers the other waveguide surface.
[0016] As a preferred solution: the optical machine includes a micro projector, and the distance between the micro projector and the entrance pupil area is less than 5 mm.
[0017] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, it can be seen from the above technical scheme that the central light passing through the optical machine forms an angle with the perpendicular line of the waveguide surface, and an extinction film is provided on the diffraction light waveguide at the imaging position which is not on the center line of the line of sight. The light at the waveguide surface position corresponding to the external environment is weakened by the extinction film and then enters the external environment; the phenomenon of light leakage from the exit pupil area to the external environment is reduced, the extinction film absorbs part of the leaked light, reduces the impact of the leaked light on the environment, and improves the user experience; for the diffraction light waveguide with light leakage in the exit pupil area, the extinction film provided in accordance with the light exit angle of the exit pupil area reduces exit pupil light leakage, prevents interference with the external environment and information leakage.
[0018] To more clearly illustrate the structural features and effects of the present invention, it is described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A schematic diagram of the three-dimensional structure of a diffraction light waveguide display device for reducing light leakage according to the present invention;
[0020] Figure 2 A schematic diagram of the first-view stereoscopic structure of the main body of a diffraction light waveguide display device for reducing light leakage according to the present invention;
[0021] Figure 3 A schematic diagram of the second-view perspective structure of the main body of a diffraction light waveguide display device for reducing light leakage according to the present invention;
[0022] Figure 4 This is a first graph showing the relationship between angle A and transmittance according to the present invention;
[0023] Figure 5 This is the second graph showing the relationship between the angle A and transmittance according to the present invention.
[0024] Description of the accompanying drawings:
[0025] In the figure: 10, diffraction optical waveguide; 11, waveguide surface; 12, entrance pupil area; 13, exit pupil area; 20, extinction film; 30, air gap; 40, optical machine. DETAILED DESCRIPTION
[0026] The present invention Figures 1 to 5 As shown, a diffraction light waveguide display device for reducing light leakage includes a diffraction light waveguide 10, an optical engine 40 and a matte film 20, wherein;
[0027] The diffraction light waveguide 10 has two waveguide surfaces 11 facing each other, and a diffraction grating area is provided on at least one waveguide surface 11, and the diffraction grating area includes an entrance pupil area 12 and at least one exit pupil area 13; the optical engine 40 is located next to the entrance pupil area 12; the matte film 20 has at least one layer provided on one of the waveguide surfaces 11 and fully covers the exit pupil area 13; the central light of the optical engine 40 forms an angle A with the perpendicular line of the waveguide surface 11; the optical engine 40 includes a micro projector, and the distance between the micro projector and the entrance pupil area 12 is less than 5 mm.
[0028] The light emitted by the optical machine 40 enters the entrance pupil area 12 in a direction with an angle A between the central light and the perpendicular line of the waveguide surface 11. The grating diffraction light in the entrance pupil area 12 is totally reflected in the diffraction optical waveguide 10 and finally reaches the exit pupil area 13. The light diffracted by the diffraction grating in the exit pupil area 13 is emitted from the two waveguide surfaces 11 positions corresponding to the exit pupil area 13 of the diffraction optical waveguide 10. The light at the position of the waveguide surface 11 corresponding to the user's eye enters the user's eye, and the light at the position of the waveguide surface 11 corresponding to the external environment enters the external environment after the light intensity is weakened by the matt film 20.
[0029] The waveguide surface 11 on the side corresponding to the user's eyes is not provided with a matte film 20, so the light entering the user's eyes will not have its light intensity reduced; while the waveguide surface 11 on the side corresponding to the external environment is provided with a matte film 20, and the light intensity is weakened after passing through the matte film 20, thereby reducing the light leakage from the external environment.
[0030] When the user's eyes and the matte film 20 are located on both sides of the diffraction light waveguide 10, the light diffracted from the exit pupil area 13 on one side is observed at the user's eyes next to the waveguide surface 11 of M1; the light diffracted from the exit pupil area 13 on the other side passes through the matte film 20 on the waveguide surface 11 of M2, and a small amount of light is emitted into the external environment, thereby reducing light leakage from the exit pupil.
[0031] The central light of the optical machine 40 forms an angle with the perpendicular line of the waveguide surface 11. A matte film 20 is provided on the diffraction light waveguide 10 where the imaging position is not on the center line of the line of sight. The light at the position of the waveguide surface 11 corresponding to the external environment is weakened by the matte film 20 and then enters the external environment; the phenomenon of light leakage from the exit pupil area 13 to the external environment is reduced, and the matte film 20 absorbs part of the leaked light, reducing the impact of the leaked light on the environment and improving the user experience; for the diffraction light waveguide 10 with light leakage in the exit pupil area 13, the matte film 20 is provided according to the light emission angle of the exit pupil area 13 to reduce light leakage from the exit pupil and prevent interference with the external environment and information leakage.
[0032] The central imaging ray of the user's eye corresponding to the exit pupil area 13 forms an angle A1 with the perpendicular line of the waveguide surface 11; the central imaging ray of the external environment corresponding to the exit pupil area 13 forms an angle A2 with the perpendicular line of the waveguide surface 11; the values of the angle A, angle A1 and angle A2 are equal.
[0033] The angle A1 and the angle A2 correspond to different light directions. The light corresponding to the angle A1 is toward the user's eyes, and the light corresponding to the angle A2 is toward the external environment; but the values of the two angles are the same.
[0034] Specifically, the diffraction light waveguide 10 has two waveguide surfaces 11 opposite to each other, namely M1 and M2. A diffraction grating area is provided on the waveguide surface 11 of M1, and the diffraction grating area includes an entrance pupil area 12 and an exit pupil area 13. The imaging center light corresponding to the user's eye in the exit pupil area 13 forms an angle A1 with the perpendicular line of the waveguide surface 11; the imaging center light corresponding to the external environment in the exit pupil area 13 forms an angle A2 with the perpendicular line of the waveguide surface 11; a matte film 20 is provided on the waveguide surface 11 of M2, and the matte film 20 at least completely covers the exit pupil area 13.
[0035] The field angle of view of the light emitted by the optical machine 40 is an included angle C, which is 10 degrees to 60 degrees; and the included angle A is 5 degrees to 40 degrees.
[0036] The matt film 20 is arranged above the waveguide surface 11, and an air gap 30 is set between the matt film 20 and the waveguide surface 11; if there is no glass on the waveguide surface 11 of M2, an air gap 30 must be set between the matt film 20 and the waveguide surface 11 of M2 to meet the total reflection condition.
[0037] The waveguide surface 11 is provided with glass for protection, and the matt film 20 is flatly attached to the side of the glass facing away from the waveguide surface 11; if there is glass on the waveguide surface 11 of M2, the matt film 20 is flatly attached to the glass surface.
[0038] The imaging light emitted from the exit pupil area 13 forms a certain angle with the perpendicular line of the waveguide surface 11, and the transmittance of the matte film 20 to the imaging light decreases as the angle increases; the larger the angle, the lower the transmittance of the light passing through the matte film 20, and the better the effect of reducing light leakage.
[0039] like Figure 4 and Figure 5 As shown in the figure, the matt film 20 has different transmittances for light incident at different angles. The transmittance is highest for light incident at 0° (or a certain specific angle), and the larger the incident angle of the light, the lower the transmittance. By adjusting the angle between the imaging light emitted from the exit pupil area 13 and the perpendicular to the waveguide surface 11, the intensity of light with a large angle can be weakened after passing through the matt film 20, thereby reducing exit pupil leakage.
[0040] The optical machine 40 is located next to the waveguide surface 11 on one side of the matte film 20, and the matte film 20 avoids covering the entrance pupil area 12; it ensures that the light emitted by the optical machine 40 enters from the entrance pupil area 12, and the matte film 20 avoids covering the entrance pupil area 12, so that the light emitted by the optical machine 40 is not affected by the matte film 20.
[0041] The micro projector emits light with a field of view angle of 30°, the central light forms an angle of 30° with the perpendicular to the waveguide surface 11, the nearest edge light forms an angle B with the perpendicular to the waveguide surface 11, and the angle B is 15°. The light emitted from the waveguide surface 11 on the side where the matte film 20 is provided enters the matte film 20 with an angle greater than 15°. The transmittance of the light entering the matte film 20 with an angle greater than 15° is less than 30%; the central light is generally the strongest, and when it enters the matte film 20 at an angle of 30°, the transmittance is only 25%.
[0042] The larger the angle between the incident light of the micro projector and the perpendicular line of the waveguide surface 11, the larger the angle between the light output angle of the exit pupil area 13 and the perpendicular line of the waveguide surface 11, the larger the angle at which the light enters the matte film 20, and the smaller the light transmittance will be, and the weaker the light entering the outside world from the waveguide will be.
[0043] The optical engine 40 is located on the side of one of the waveguide surfaces 11 away from the matte film 20, and the matte film 20 covers the other waveguide surface 11 in its entirety; the optical engine 40 is located on the side of the waveguide surface 11 away from the matte film 20, and the matte film 20 can cover the other waveguide surface 11 in its entirety, and the matte film 20 will not affect the light emitted by the optical engine 40 from entering the pupil area 12.
[0044] The use method and principle of the diffraction light waveguide display device for reducing light leakage are as follows:
[0045] The light emitted by the optical machine enters the entrance pupil area in the direction of the angle A between the central light and the perpendicular line of the waveguide surface. The grating diffraction light in the entrance pupil area is totally reflected in the diffraction light waveguide and finally reaches the exit pupil area. The light diffracted by the diffraction grating in the exit pupil area is emitted from the two waveguide surface positions corresponding to the exit pupil area of the diffraction light waveguide. The light at the waveguide surface position corresponding to the user's eye side enters the user's eye, and the light at the waveguide surface position corresponding to the external environment side enters the external environment after the light intensity is weakened by the extinction film.
[0046] The design focus of the present invention is that the central light passing through the optical machine forms an angle with the perpendicular line of the waveguide surface, and an extinction film is provided on the diffraction light waveguide at the imaging position which is not on the center line of the line of sight. The light at the waveguide surface position corresponding to the external environment is weakened by the extinction film before entering the external environment; the phenomenon of light leakage from the exit pupil area to the external environment is reduced, and the extinction film absorbs part of the leaked light, reducing the impact of the leaked light on the environment and improving the user experience; for the diffraction light waveguide with light leakage in the exit pupil area, the extinction film is provided in accordance with the light emission angle of the exit pupil area to reduce light leakage from the exit pupil and prevent interference with the external environment and information leakage.
[0047] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.
Claims
1. A diffraction light waveguide display device with reduced light leakage, characterized in that: The device comprises a diffraction light waveguide, an optical engine, and a matte film. The diffraction light waveguide has two waveguide surfaces facing each other, at least one of which is provided with a diffraction grating region, wherein the diffraction grating region includes an entrance pupil region and at least one exit pupil region. The optical engine is located beside the entrance pupil region. The matte film has at least one layer provided on one of the waveguide surfaces and fully covers the exit pupil region. The central ray of the optical engine forms an angle A with a perpendicular line to the waveguide surface. The central ray of the imaging of the user's eyes corresponding to the exit pupil area forms an angle A1 with the perpendicular line of the waveguide surface; the central ray of the imaging of the external environment corresponding to the exit pupil area forms an angle A2 with the perpendicular line of the waveguide surface; the values of the angle A, angle A1 and angle A2 are equal; The imaging light emitted from the exit pupil area forms a certain angle with the perpendicular line of the waveguide surface, and the transmittance of the matte film to the imaging light decreases as the angle increases.
2. The diffraction light waveguide display device with reduced light leakage according to claim 1, characterized in that: The light emitted by the optical machine enters the entrance pupil area in the direction of the angle A between the central light and the perpendicular line of the waveguide surface. The grating diffraction light in the entrance pupil area is totally reflected in the diffraction light waveguide and finally reaches the exit pupil area. The light diffracted by the diffraction grating in the exit pupil area is emitted from the two waveguide surface positions corresponding to the exit pupil area of the diffraction light waveguide. The light at the waveguide surface position corresponding to the user's eye side enters the user's eye, and the light at the waveguide surface position corresponding to the external environment side enters the external environment after the light intensity is weakened by the extinction film.
3. The diffraction light waveguide display device with reduced light leakage according to claim 2, characterized in that: The field angle of view of the light emitted by the optical machine is angle C, which is 10 degrees to 60 degrees; the above-mentioned angle A is 5 degrees to 40 degrees.
4. The diffraction light waveguide display device with reduced light leakage according to claim 1, characterized in that: The matt film is arranged above the waveguide surface, and an air gap is arranged between the matt film and the waveguide surface.
5. The diffraction light waveguide display device with reduced light leakage according to claim 1, characterized in that: The waveguide surface is provided with glass for protection, and the matt film is flatly attached to the side of the glass facing away from the waveguide surface.
6. The diffraction light waveguide display device with reduced light leakage according to claim 1, characterized in that: The optical engine is located beside the waveguide surface on one side of the matte film, and the matte film avoids covering the entrance pupil area.
7. The diffraction light waveguide display device with reduced light leakage according to claim 1, characterized in that: The optical engine is located beside one of the waveguide surfaces away from the matte film, and the matte film entirely covers the other waveguide surface.
8. The diffraction light waveguide display device with reduced light leakage according to claim 1, characterized in that: The optical machine includes a micro projector, and the distance between the micro projector and the entrance pupil area is less than 5 mm.
Citation Information
Patent Citations
AR glasses
CN113687512A
Anti-light-leakage augmented reality display device
CN114236826A