Anti-light-leakage AR diffraction optical waveguide display device

Abstract

The utility model discloses a light leakage prevention AR diffraction optical waveguide display device, which comprises a low-light level machine and an optical waveguide main body, a coupling-in grating and a coupling-out grating which are equal in period are arranged on the optical waveguide main body, protective glass is arranged between the low-light level machine and the optical waveguide main body, and a metal wire grating structure is arranged on the protective glass. The area length and width of the metal wire grating are larger than the length and width of the coupling-out area of the coupling-out grating, the period of the metal wire grating is small enough so that only zero-level components exist when light passes through the metal wire grating, the period direction of the metal wire grating is perpendicular to the polarization direction of leaked light, and the leaked light is restrained from penetrating through the protective glass. According to the utility model, diffracted light can be prevented from leaking to the external environment through the protective glass, so that the privacy of a user is protected, the part of light is reflected to the AR optical waveguide to be reused, and the light intensity of the human eye side is increased.

Description

Technical Field

[0001] The utility model relates to the AR field, and in particular to an AR diffraction light waveguide display device capable of preventing light leakage. Background Art

[0002] In recent years, the way people interact with computers has developed rapidly. Augmented Reality (AR) display can provide users with more dimensional information and has been widely used in military industry, 3D modeling, real-time tracking, medical technology, etc., and has received widespread attention. Among many solutions, diffraction waveguide has become one of the mainstream technical solutions for AR near-eye display due to its advantages such as light volume, high transparency, large field of view, and easier mass production.

[0003] In common AR diffraction waveguide devices, when the light emitted by the micro-optical machine enters the optical waveguide through the coupling grating, it encounters the upper and lower interfaces of the optical waveguide and generates full emission. When the light propagates through the coupling grating area, two new diffraction beams in different directions are generated. One beam of diffraction light propagates toward the human eye, allowing the human eye to receive information from the micro-optical machine, and the other beam of diffraction light propagates in the opposite direction of the human eye and leaks into the external environment, causing privacy and security issues for users. Therefore, the light leakage problem has become a major difficulty restricting the development and application of AR diffraction waveguide technology. Summary of the invention

[0004] The technical problem to be solved by the utility model is to provide an AR diffraction light waveguide display device that is anti-light leakage, and the use of the device can effectively avoid the privacy and security problems of users caused by diffraction light in the existing AR diffraction light waveguide device.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is: a light leakage-proof AR diffraction optical waveguide display device, including a micro-optical engine and an optical waveguide body, on which a coupling-in grating and a coupling-out grating are arranged on the optical waveguide body facing the micro-optical engine; a protective glass is arranged between the micro-optical engine and the optical waveguide body, and a metal wire grid structure is arranged on the protective glass facing the optical waveguide body.

[0006] The periods of the in-coupling grating and the out-coupling grating are equal.

[0007] The length and width of the metal wire grid are greater than the length and width of the out-coupling region of the out-coupling grating.

[0008] The period of the metal wire grid is small enough so that only the 0th order component of light passes through the metal wire grid; the periodic direction of the metal wire grid, i.e., the arrangement direction, is perpendicular to the polarization direction of the leaked light, thereby suppressing the leaked light from passing through the protective glass. The metal wire grid also suppresses the TE polarization component of natural light in the external environment from passing through the AR device to the human eye, but the TM component in natural light can still pass through the AR optical waveguide with a higher transmittance to be perceived by the user.

[0009] The metal wire grid is made of aluminum.

[0010] The principle of the utility model is that the TE light emitted by the micro-optical machine of the display device enters the optical waveguide plate through the coupling grating, undergoes full emission and is transmitted to the coupling grating, and two new diffracted lights are generated in the coupling grating area. The first diffracted light enters the human eye, so that the human eye can receive the image information of the optical machine. The second diffracted light propagates to the metal wire grid area of ​​the protective glass, and is basically reflected by the metal wire grid and re-enters the human eye, increasing the light utilization efficiency on the human eye side.

[0011] The utility model adopts an AR diffraction optical waveguide display device with anti-light leakage designed by the above technical scheme. By preparing a metal wire grid structure on the protective glass of the waveguide plate device, it can suppress the diffraction light from leaking through the protective glass to the external environment, thereby protecting the privacy of the user. At the same time, this part of the light is reflected to the AR optical waveguide and reused, increasing the light intensity on the human eye side, which has obvious advantages compared with the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram showing the AR diffraction optical waveguide device for preventing light leakage of the utility model;

[0013] Figure 2 Ray tracing diagram showing the incident light at an angle of (0°, 0°) into a conventional AR diffractive waveguide device (without metal wire grid);

[0014] Figure 3 Ray tracing diagram showing the incident light at (-13.5°, 7.5°) angles on a conventional AR diffraction waveguide device (without metal wire grid);

[0015] Figure 4 A ray tracing diagram showing a light incident at an angle of (0°, 0°) onto an anti-light leakage AR diffraction waveguide device (including a metal wire grid);

[0016] Figure 5 A ray tracing diagram showing the incident light at an angle of (-13.5°, 7.5°) onto the anti-light leakage AR diffraction waveguide device (including a metal wire grid).

[0017] In the figure: 100-waveguide, 101-input grating, 102-output grating, 103-metal wire grid, 104-protective glass, 105-optical machine, 200-light, 201-second diffracted light, 202-light generated by reflection of metal wire grid, 204-first diffracted light, 301-human eye observation side area, 302-light leakage side area. DETAILED DESCRIPTION

[0018] The following is a detailed description of the AR diffraction light waveguide display device for preventing light leakage according to the present invention in conjunction with the accompanying drawings.

[0019] The utility model discloses an AR diffraction light waveguide display device which prevents light leakage, see Figure 1 , Figure 1 A schematic diagram of a single green AR diffraction optical waveguide device for preventing light leakage in the xz plane, specifically comprising: an optical machine 105, a waveguide 100, an in-coupling grating 101 and an out-coupling grating 102 on the waveguide 100, and a metal wire grating 103 on a protective glass 104, wherein the in-coupling grating 101 and the out-coupling grating 102 have the same period along the x direction. The material of the metal wire grating 103 is aluminum in this embodiment, and the length and width of the metal wire grating 103 are greater than the length and width of the out-coupling region of the out-coupling grating 102. The period of the metal wire grating 103 of the utility model should be small enough so that light passing through the metal wire grating 103 has only a zero-order component. The periodic direction (arrangement direction) of the metal wire grid 103 is perpendicular to the polarization direction (TE) of the leaked light, that is, the polarization direction of the light is consistent with the direction of the grating lines, which inhibits it from passing through the protective glass 104. The metal wire grid 103 also inhibits the TE polarization component in the natural light of the external environment from passing through the AR device to the human eye, but the TM component in the natural light can still pass through the AR optical waveguide with a higher transmittance for the user to perceive. In this embodiment, the incident light of the optical machine 105 is TE polarization (the electric field polarization direction is along the y-axis), and the metal wire grid 103 is periodically arranged along the x-direction to inhibit the second diffracted light 201 from passing through the protective glass 104. In the figure, area 301 is the human eye observation side area, and 302 is the light leakage side area. The light 200 is incident on the surface of the coupling-in grating 101 by the optical machine 105. After being coupled in by the grating, the light 200 is fully emitted in the waveguide 100. After passing through the coupling-out grating 102, it will be diffracted out of the waveguide. The first diffracted light 204 enters the area 301 on the side where the human eye observes. After the second diffracted light 201 is incident on the metal wire grid 103, most of it is reflected by the metal wire grid 103 to generate the light 202 that re-enters the waveguide 100, so that the second diffracted light 201 is reused by the optical waveguide, thereby increasing the light power intensity in the area 301 on the side where the human eye observes.

[0020] In conventional AR optical waveguide devices, ordinary protective glass only protects the coupling-in and coupling-out grating structures on the AR optical waveguide from being damaged, but does not have the function of preventing light leakage. Figure 2 and Figure 3It is a ray tracing diagram of TE polarized light emitted by the optical machine at normal incidence angles (0°, 0°) and oblique incidence angles (-13.5°, 7.5°) in a conventional AR optical waveguide device without a metal wire grid. The light totally reflected in the waveguide 100 will diffract out of the waveguide after passing through the outcoupling grating and will be incident on the human eye observation side area 301 and the light leakage side area 302. The light in the human eye observation side area 301 will be received by the human eye, and the light in the light leakage side area 302 will cause information leakage.

[0021] The anti-light leakage AR diffraction light waveguide display device of the utility model can effectively suppress the diffraction light from leaking to the external environment and protect the privacy of users. Figure 4 and Figure 5 It is a ray tracing diagram of TE polarized light emitted by the optical machine of the utility model in an AR optical waveguide device with a metal wire grid at normal incidence angles (0°, 0°) and oblique incidence angles (-13.5°, 7.5°). The metal wire grid 103 suppresses the second diffraction light 201 from being transmitted to the light leakage side area 302, thereby preventing light leakage from occurring in the device.

Claims

1. An AR diffraction optical waveguide display device with anti-light leakage, comprising a micro-optical machine and an optical waveguide body, characterized in that A coupling-in grating and a coupling-out grating are arranged on the optical waveguide body facing the micro-optical machine; a protective glass is arranged between the micro-optical machine and the optical waveguide body, and a metal wire grid structure is arranged on the protective glass facing the optical waveguide body.

2. The AR diffraction light waveguide display device according to claim 1, characterized in that The periods of the in-coupling grating and the out-coupling grating are equal.

3. The AR diffraction light waveguide display device with anti-light leakage according to claim 1, characterized in that The length and width of the metal wire grid are greater than the length and width of the out-coupling region of the out-coupling grating.

4. The AR diffraction light waveguide display device with anti-light leakage according to claim 1, characterized in that The period of the metal wire grid is small enough so that only the 0th order component of light passes through the metal wire grid; the periodic direction of the metal wire grid, i.e., the arrangement direction, is perpendicular to the polarization direction of the leaked light, thereby suppressing the leaked light from passing through the protective glass. The metal wire grid also suppresses the TE polarization component of natural light in the external environment from passing through the AR device to the human eye, but the TM component in natural light can still pass through the AR optical waveguide with a higher transmittance to be perceived by the user.

5. The AR diffraction light waveguide display device with anti-light leakage according to claim 1, characterized in that The metal wire grid is made of aluminum.

Images