Eye movement tracking device, preparation method thereof and display equipment

Abstract

The invention discloses an eye movement tracking device, a preparation method thereof and display equipment, and relates to the technical field of display, and the preparation method of the eye movement tracking device comprises the following steps: providing a waveguide substrate, and delimiting a first coupling-in grating region and a first coupling-out grating region on the waveguide substrate; based on an equivalent exposure theory, converting preset exposure parameters of the first coupling-in grating and the first coupling-out grating into space exposure parameters in an equivalent exposure parameter space of the first coupling-in grating and the first coupling-out grating; respectively preparing a first coupling-in grating and a first coupling-out grating in a first coupling-in grating area and a first coupling-out grating area of the waveguide substrate according to the space exposure parameters of the first coupling-in grating and the first coupling-out grating to form a waveguide; the illumination light source, the waveguide and the detector are assembled to form the eye movement tracking device, and according to the eye movement tracking device, the manufacturing method thereof and the display equipment, the manufacturing yield of the eye movement tracking device can be increased.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular, to an eye tracking device and a preparation method thereof, and a display device. Background Art

[0002] As a method to accurately identify the shape and movement path of the eyeball, eye tracking technology can significantly improve the user experience in human-computer interaction and is an important tool in the field of virtual reality and augmented reality. Its basic principle can be summarized as illuminating the eye structure, using a detector to obtain the reflected light of the eye structure, extracting the morphological features of the eye structure through the reflected light, and analyzing the gaze direction and gaze point of the human eye from these features. Traditional eye trackers are usually implemented using planar beam splitters and relatively large optical devices, which results in a large size and is difficult to integrate into AR / VR displays.

[0003] Volume holographic waveguides are widely used in the field of AR display because of their low cost, easy automated manufacturing, good mass production, and high diffraction efficiency when the Bragg condition is met. Light has the characteristics of total reflection transmission and expansion in the waveguide, and non-traditional lighting can be realized based on this characteristic. Applying this lighting method to the field of eye tracking can meet the needs of thin, compact, wide field of view, large exit pupil, and high transparency eye trackers.

[0004] In the field of eye tracking, infrared light is usually used as illumination light in order not to obstruct the line of sight, which puts forward requirements for the manufacture of infrared volume holographic waveguides; the grating in the existing holographic waveguide is realized by double-beam interference, and in order to meet the total reflection transmission, at least one beam of light needs to be coupled into the waveguide using a coupling prism or a mask. The cost of the mask is too high, and a refractive index matching liquid needs to be applied between the prism and the waveguide. During the mass production process, there will be problems such as uneven thickness of the matching liquid and bubbles, which will cause grating defects during the exposure process, resulting in a low manufacturing yield. Summary of the invention

[0005] The purpose of the present application is to provide an eye tracking device and a preparation method thereof, and a display device, which can improve the manufacturing yield of the eye tracking device.

[0006] On the one hand, an embodiment of the present application provides a method for preparing an eye tracking device, including: providing a waveguide substrate, and defining a first coupling-in grating area and a first coupling-out grating area on the waveguide substrate; based on the equivalent exposure theory, converting the preset exposure parameters of the first coupling-in grating and the first coupling-out grating into spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating and the first coupling-out grating; preparing the first coupling-in grating and the first coupling-out grating in the first coupling-in grating area and the first coupling-out grating area of ​​the waveguide substrate according to the spatial exposure parameters of the first coupling-in grating and the first coupling-out grating to form a waveguide; assembling an illumination light source, a waveguide and a detector to form an eye tracking device, so that the illumination light beam emitted by the illumination light source is irradiated to the human eye directly or through the waveguide and reflected by the human eye, and the detector is used to receive the reflected light of the human eye.

[0007] As an implementable manner, the preset exposure parameters are: determining the reference light of the first coupling grating according to the information of the first coupling grating signal light and the exposure wavelength λ1 of the reference light and the signal light; and according to the reference light signal light and the exposure wavelength λ1 of the reference light and the signal light to calculate the grating vector According to the grating Calculate the rotation angles of the reference light, signal light, and waveguide substrate.

[0008] As an implementable manner, based on the equivalent exposure theory, the preset exposure parameters of the first coupling-in grating and the first coupling-out grating are converted into spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating and the first coupling-out grating, including: rotating the reference light, the signal light, and the waveguide substrate at a rotation angle to obtain the rotated reference light signal light and the position of the waveguide substrate; changing the exposure wavelength λ1 of the reference light and the signal light to the recording wavelength λ2, and rotating the rotated reference light and the signal light at least once to obtain the vector of the exposure material of the reference light And the vector in the exposure material of the signal light According to the exposure material of the reference light, the vector And the vector in the exposure material of the signal light Determine the vector of the reference light in air And the vector of the signal light in the air According to the vector in the air of the reference light And the vector of the signal light in the air The incident angle of the reference light and the incident angle of the signal light are determined.

[0009] As an implementable method, a first coupling grating is prepared in a first coupling grating region according to spatial parameters of the first coupling grating, including: performing interference exposure on a corresponding position of the rotated waveguide substrate according to an incident angle of a reference light and an incident angle of a signal light to obtain the first coupling grating.

[0010] As an implementable method, a volume holographic photosensitive material is formed in the waveguide substrate at positions corresponding to the first coupling-in grating and the first coupling-out grating, and the signal light and the reference light are exposed at the volume holographic photosensitive material to form a first coupling-in grating, which is a transmission diffraction grating.

[0011] As an implementable manner, the signal light and the reference light of the first coupling-in grating are both parallel light; the signal light of the first coupling-out grating is scattered light, and the reference light is parallel light.

[0012] On the other hand, an embodiment of the present application provides an eye tracking device, which is prepared using the above-mentioned eye tracking device preparation method, and includes a waveguide, and an illumination light source and a detector respectively arranged at intervals from the waveguide. The illumination light beam emitted by the illumination light source is irradiated to the human eye directly or through the waveguide, and the detector is used to receive the reflected light of the human eye.

[0013] As an implementable manner, the detector and the illumination light source are arranged on the same side of the waveguide, the illumination light beam emitted by the light source is coupled into the waveguide through the first coupling grating of the waveguide and coupled out to the human eye by the first coupling grating, and the reflected light of the human eye is received by the detector; or, the illumination light beam emitted by the light source is irradiated to the human eye, and the reflected light of the human eye is emitted to the detector through the waveguide.

[0014] As an implementable method, a reflection coupling-in grating and a reflection coupling-out grating are also arranged on the waveguide, the first coupling-out grating and the reflection coupling-in grating are stacked, the detector is arranged on the light output side of the reflection coupling-out grating, and the reflected light is coupled into the waveguide by the reflection coupling-in grating and coupled out to the detector by the reflection coupling-out grating.

[0015] On the other hand, an embodiment of the present application provides a display device, including the above-mentioned eye tracking device, and a second coupling-in grating and a second coupling-out grating arranged on the waveguide of the eye tracking device, the second coupling-in grating is arranged to fit the first coupling-in grating, the second coupling-out grating is arranged to be stacked with the second coupling-out grating, the waveguide is provided with an optical machine corresponding to the second coupling-in grating, and an image light beam emitted by the optical machine is coupled into the waveguide by the second coupling-in grating and coupled out by the second coupling-out grating for imaging.

[0016] The beneficial effects of the embodiments of the present application include:

[0017] The present application provides a method for preparing an eye tracking device, comprising: providing a waveguide substrate, and defining a first coupling-in grating region and a first coupling-out grating region on the waveguide substrate; based on the equivalent exposure theory, converting the preset exposure parameters of the first coupling-in grating and the first coupling-out grating into spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating and the first coupling-out grating; preparing the first coupling-in grating and the first coupling-out grating in the first coupling-in grating region and the first coupling-out grating region of the waveguide substrate to form a waveguide according to the spatial exposure parameters of the first coupling-in grating and the first coupling-out grating; using the equivalent exposure theory, solving the spatial exposure parameters in the equivalent exposure parameter space, so that when preparing the first coupling-in grating and the first coupling-out grating, neither a mask nor a coupling prism is required, that is, a prism-free manufacturing condition is achieved, thereby avoiding the cost increase caused by the mask and the poor yield caused by the coupling prism. The eye tracking device is formed by assembling an illumination light source, a waveguide, and a detector, so that the illumination light beam emitted by the illumination light source is irradiated to the human eye directly or through the waveguide and is reflected by the human eye, and the detector is used to receive the reflected light from the human eye. Therefore, the preparation method of the eye tracking device of the embodiment of the present application can improve the manufacturing yield of the eye tracking device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A flow chart of a method for preparing an eye tracking device provided in an embodiment of the present application;

[0020] Figure 2 One of the state diagrams of a method for preparing an eye tracking device provided in an embodiment of the present application;

[0021] Figure 3 A second state diagram of a method for preparing an eye tracking device provided in an embodiment of the present application;

[0022] Figure 4 One of the structural schematic diagrams of an eye tracking device provided in an embodiment of the present application;

[0023] Figure 5 A second structural diagram of an eye tracking device provided in an embodiment of the present application;

[0024] Figure 6 A third structural diagram of an eye tracking device provided in an embodiment of the present application;

[0025] Figure 7 One of the structural schematic diagrams of a display device provided in an embodiment of the present application;

[0026] Figure 8 One of the optical path diagrams of a display device provided in an embodiment of the present application;

[0027] Fig. 9 A second structural schematic diagram of a display device provided in an embodiment of the present application;

[0028] Fig.10 A second optical path diagram of a display device provided in an embodiment of the present application;

[0029] Fig.11 A third optical path diagram of a display device provided in an embodiment of the present application;

[0030] Fig.12 A third structural schematic diagram of a display device provided in an embodiment of the present application;

[0031] Fig.13 This is a fourth optical path diagram of a display device provided in an embodiment of the present application.

[0032] Icon: 011-illumination light source; 012-illumination light beam; 013-waveguide substrate; 014-first coupling-in grating; 015-first coupling-out grating; 016-first coupling-out light beam; 017-human eye; 018-reflected light; 019-detector; 031-first coupling-in grating region; 032-first coupling-out grating region; 071-reflection coupling-in grating; 072-reflection coupling-out grating; 021-optical machine; 022-image light beam; 023-second coupling-in grating; 024-second coupling-out grating; 025-second coupling-out light beam; 041-first turning grating; 042-second turning grating; 051-first two-dimensional grating; 052-second two-dimensional grating. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of this application, it should be noted that the terms "center", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0037] The eye tracking device is used to obtain the gaze direction and gaze point of the human eye based on the reflected light of the human eye, so as to significantly improve the user experience in human-computer interaction. In the prior art, the eye tracking device uses a volume holographic waveguide for light transmission. The grating in the volume holographic waveguide is realized by double-beam interference, but the manufacturing yield is low during the interference process.

[0038] The present application embodiment provides a method for preparing an eye tracking device, such as Figure 1 As shown, including:

[0039] S10: providing a waveguide substrate 013, and defining a first coupling-in grating region 031 and a first coupling-out grating region 032 on the waveguide substrate 013;

[0040] According to the setting of the eye tracking device, a first coupling-in grating area 031 and a first coupling-out grating area 032 are divided on the waveguide substrate 013, wherein the first coupling-in grating area 031 is used to set the first coupling-in grating 014 for coupling the illumination light beam 012 into the waveguide substrate 013; the first coupling-out grating area 032 is used to set the first coupling-out grating 015 for coupling the illumination light beam 012 out of the waveguide substrate 013.

[0041] S20: based on the equivalent exposure theory, converting the preset exposure parameters of the first coupling-in grating 014 and the first coupling-out grating 015 into spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating 014 and the first coupling-out grating 015;

[0042] Using the equivalent exposure theory, we can solve the spatial exposure parameters in the equivalent exposure parameter space, that is, find a specific grating vector The rotation angle γ around the kz axis makes the angles of the signal light and the reference light with respect to the normal line of the waveguide surface smaller than the full emission critical angle of the waveguide substrate 013, thereby satisfying the prism-free manufacturing conditions.

[0043] S30: preparing the first coupling-in grating 014 and the first coupling-out grating 015 in the first coupling-in grating region 031 and the first coupling-out grating region 032 of the waveguide substrate respectively according to the spatial exposure parameters of the first coupling-in grating 014 and the first coupling-out grating 015 to form a waveguide;

[0044] When preparing the first coupling-in grating 014 and the first coupling-out grating 015, neither a mask nor a coupling prism is required, that is, a prism-free manufacturing condition is achieved, thereby avoiding the cost increase caused by the mask and the poor yield caused by the coupling prism.

[0045] S40: Figure 4 As shown, an eye tracking device is formed by assembling an illumination light source 011, a waveguide and a detector 019, so that the illumination light beam 012 emitted by the illumination light source 011 is irradiated to the human eye 017 directly or through the waveguide and is reflected by the human eye 017, and the detector 019 is used to receive the reflected light 018 of the human eye 017.

[0046] In practical applications, eye tracking devices are usually used in display devices. In order not to obstruct the line of sight, infrared light is usually used as the illumination light, that is, the illumination light source 011 is an infrared light source.

[0047] The preparation method of the eye tracking device provided in the present application includes: providing a waveguide substrate 013, and defining a first coupling grating area 031 and a first coupling grating area 032 on the waveguide substrate 013; based on the equivalent exposure theory, converting the preset exposure parameters of the first coupling grating 014 and the first coupling grating 015 into spatial exposure parameters in the equivalent exposure parameter space of the first coupling grating 014 and the first coupling grating 015; and converting the preset exposure parameters of the first coupling grating 014 and the first coupling grating 015 into spatial exposure parameters in the equivalent exposure parameter space of the first coupling grating 014 and the first coupling grating 015 according to the spatial exposure parameters of the first coupling grating 014 and the first coupling grating 015. The first coupling grating 014 and the first coupling grating 015 are prepared in the first coupling grating region 031 and the first coupling grating region 032 respectively by using exposure parameters; the spatial exposure parameters in the equivalent exposure parameter space are solved by using the equivalent exposure theory, so that when preparing the first coupling grating 014 and the first coupling grating 015, neither a mask nor a coupling prism is required, that is, a prism-free manufacturing condition is achieved, thereby avoiding the cost increase caused by the mask and the poor yield caused by the coupling prism. The illumination light source 011, the waveguide and the detector 019 are assembled to form an eye tracking device, so that the illumination light beam 012 emitted by the illumination light source 011 is directly or through the waveguide to the human eye 017 and is reflected by the human eye 017, and the detector 019 is used to receive the reflected light 018 of the human eye 017. Therefore, the preparation method of the eye tracking device of the embodiment of the present application can improve the manufacturing yield of the eye tracking device.

[0048] Optionally, the preset exposure parameters are:

[0049] S51: Determine the reference light of the first coupling grating 014 according to the information of the first coupling grating 014 signal light and the exposure wavelength λ1 of the reference light and the signal light;

[0050] Specifically, a Cartesian coordinate system is established, with the plane where the waveguide substrate 013 is located as the X-axis and the Y-axis, and the normal line of the waveguide substrate 013 as the Z-axis. and signal light decomposed into the Cartesian coordinate system, the reference light and signal light They all have components in three directions.

[0051] S52: and according to the reference light signal light and the exposure wavelength λ1 of the reference light and the signal light to calculate the grating vector According to the grating The rotation angles of the reference light, the signal light, and the waveguide substrate 013 are calculated.

[0052] Specifically, according to the reference light signal light The difference between the values ​​of And according to the raster vector The rotation angles of the reference light, the signal light, and the waveguide substrate 013 are calculated.

[0053] In an achievable manner of the embodiment of the present application, based on the equivalent exposure theory, the preset exposure parameters of the first coupling-in grating 014 and the first coupling-out grating 015 are converted into spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating 014 and the first coupling-out grating 015, including:

[0054] S21: Rotate the reference light, the signal light and the waveguide substrate 013 at a rotation angle to obtain the rotated reference light signal light and the position of the waveguide substrate 013;

[0055] The reference light and the signal light are rotated according to the above rotation angle. Specifically, the reference light signal light The waveguide substrate 013 is rotated multiple times around different coordinate axes to obtain the rotated vector of the reference light. Rotated vector of signal light And the material position of the waveguide substrate 013 after rotation.

[0056] S22: changing the exposure wavelength λ1 of the reference light and the signal light to the recording wavelength λ2, and rotating the rotated reference light and the signal light at least once to obtain the vector of the exposure material of the reference light And the vector in the exposure material of the signal light

[0057] Specifically, for the reference light signal light After the waveguide substrate 013 rotates multiple times, the exposure wavelength λ1 of the reference light and the signal light is converted to the recording wavelength λ2. After the exposure wavelength λ1 is converted to the recording wavelength λ2, the vectors of the reference light and the signal light change accordingly. At this time, the position of the waveguide substrate 013 after multiple rotations is kept unchanged, and the rotated vector of the reference light Rotated vector of signal light Rotate at least one side around the same coordinate axis to obtain the vector of the reference light in the exposed material And the vector in the exposure material of the signal light Make the reference light exposure material vector And the vector in the exposure material of the signal light They are all located in the two-dimensional coordinate system YOZ where the equivalent plane is located, and the vector in the exposure material of the reference light is determined. And the vector in the exposure material of the signal light Conversion relationship at different wavelengths and different Z-axis rotation angles.

[0058] Among them, the vector of the reference light exposure material And the vector in the exposure material of the signal light The conversion relationship under different wavelengths and different Z-axis rotation angles is an equivalent exposure condition. Regardless of whether the opening light and the signal light meet the total reflection condition of the waveguide substrate 013 and the air, the equivalent exposure condition is established to achieve decoupling of wavelength conversion.

[0059] S23: Exposure material according to the reference light vector And the vector in the exposure material of the signal light Determine the vector of the reference light in air And the vector of the signal light in the air

[0060] According to the exposure material of the reference light, the vector And the vector in the exposure material of the signal light Determine the reference light of different types of volume holographic gratings by the air vector incident in the air And the vector of the air in which the signal light is incident from the air

[0061] S24: Based on the vector of the reference light in air And the vector of the signal light in the air The incident angle of the reference light and the incident angle of the signal light are determined.

[0062] Optionally, based on the vector of the reference light in air Determine the polar angle and azimuth angle of the reference light incident from the air to the waveguide substrate 013 to obtain the incident angle of the reference light. The polar angle and azimuth angle of the signal light incident from the air to the waveguide substrate 013 are determined to obtain the incident angle of the reference light. The incident angle of the reference light and the incident angle of the signal light are used as spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating 014 and the first coupling-out grating 015, and the first coupling-in grating 014 and the first coupling-out grating 015 are manufactured according to the spatial exposure parameters.

[0063] The equivalent exposure theory of the embodiment of the present application is that before the wavelength of the reference light and the wavelength of the signal light change, the rotated vector of the reference light, the rotated vector of the signal light, and the rotated position of the waveguide substrate 013 are determined by multiple rotations; after the wavelength of the reference light and the wavelength of the signal light change, the waveguide substrate 013 keeps the rotated position unchanged, and the material vector of the reference light and the material vector of the signal light are determined by at least one rotation of the rotated vector of the reference light and the rotated vector of the signal light, and the equivalent exposure conditions of the material vector of the reference light and the material vector of the signal light during wavelength conversion are obtained, thereby achieving decoupling of wavelength conversion. Based on the equivalent exposure conditions of the material vector of the reference light and the material vector of the signal light, the air vector of the reference light and the air vector of the signal light are obtained, and then the incident angle of the reference light and the incident angle of the signal light are obtained, thereby achieving spatial decoupling. The incident angle of the reference light and the incident angle of the reference light are used as volume exposure parameters, and according to the volume holographic grating exposure parameters, the reference light and the signal light are incident on the waveguide substrate 013 from the air, and the holographic photosensitive material located on the rotated waveguide substrate 013 is subjected to double-beam interference exposure to manufacture a volume holographic grating.

[0064] Optionally, the first coupling grating 014 is prepared in the first coupling grating region 031 according to the spatial parameters of the first coupling grating 014, including: performing interference exposure on the corresponding position of the rotated waveguide substrate 013 according to the incident angle of the reference light and the incident angle of the signal light to obtain the first coupling grating 014.

[0065] The incident angle of the reference light and the incident angle of the reference light are used as volume exposure parameters, and according to the volume holographic grating exposure parameters, the reference light and the signal light are incident on the waveguide substrate 013 from the air, and the holographic photosensitive material located on the rotated waveguide substrate 013 is exposed by double-beam interference to manufacture the volume holographic grating. Through wavelength conversion decoupling and spatial decoupling, the required volume holographic grating can be exposed under equivalent conditions, thereby reducing the manufacturing difficulty and manufacturing cost of the volume holographic grating.

[0066] In one achievable method of the embodiment of the present application, a volume holographic photosensitive material is formed in the waveguide substrate 013 at positions corresponding to the first coupling-in grating 014 and the first coupling-out grating 015, and the signal light and the reference light are exposed at the volume holographic photosensitive material to form the first coupling-in grating 014, and the first coupling-in grating 014 is a transmission diffraction grating.

[0067] It should be noted that the embodiment of the present application takes the first coupling-in grating 014 as an example to introduce the equivalent exposure theory. It can be understood that the equivalent exposure theory of the first coupling-out grating 015 is the same as that of the first coupling-in grating 014, that is, the equivalent exposure theory can be used to prepare the first coupling-in grating 014, the first coupling-out grating 015, and the turning grating, etc.

[0068] Optional, such as Figure 2 and Figure 3 As shown, the signal light and the reference light of the first coupling-in grating 014 are both parallel light; the signal light of the first coupling-out grating 015 is scattered light, and the reference light is parallel light.

[0069] Specifically, Figure 2 As shown, the first coupling grating 014 is used to couple the illumination light beam 012 into the waveguide substrate 013, so that the illumination light beam 012 propagates by total reflection in the waveguide substrate 013. On this basis, when the first coupling grating 014 is formed, the reference light and the signal light are both parallel light.

[0070] The first out-coupling grating 015 is used to couple out the illumination light beam 012 to the human eye 017. In order to achieve the illumination effect of the illumination light beam 012, the first out-coupling grating 015 needs to couple out the scattered illumination light. On this basis, when the first out-coupling grating 015 is formed, the signal light is the scattered light, and the reference light is the parallel light. Figure 3 Specifically, the parallel reference light and the divergent signal light interfere in the first out-coupling region to form the first out-coupling grating 015. When the diffracted light of the first in-coupling grating 014 is totally reflected in the waveguide and propagates to the first out-coupling grating 015, the divergent signal light will be reproduced and coupled out of the waveguide substrate 013 in the form of scattered light, thereby achieving the purpose of illumination.

[0071] Table 1. Equivalent exposure manufacturing conditions of the first outcoupling optical element:

[0072]

[0073] Table 1 is an equivalent exposure parameter table of the reflective coupled volume holographic grating provided in an embodiment of the present application. As shown in Table 1, the preset exposure wavelength λ is 500nm, the preset recording wavelength λh is 550nm, the preset refractive index n of the holographic photosensitive material is 1.51, the preset total reflection angle θt is 50°, the preset Z-axis rotation angle γ is 15°, and the polar angle θr of the signal light is finally determined to be 118.4°, the azimuth angle φr of the first light beam is 0°, the polar angle θs of the reference light is 86.36°, and the azimuth angle φs of the reference light is 0°.

[0074] In another aspect, an embodiment of the present application provides an eye tracking device, which is prepared by the above-mentioned preparation method of the eye tracking device, such as Figure 4 , Figure 5 as well as Figure 6 As shown, it includes a waveguide, and an illumination light source 011 and a detector 019 which are respectively arranged at intervals from the waveguide. The illumination light beam 012 emitted by the illumination light source 011 irradiates the human eye 017 directly or through the waveguide, and the detector 019 is used to receive the reflected light 018 of the human eye 017.

[0075] In one possible implementation of the embodiment of the present application, Figure 4 and Figure 5 As shown, the detector 019 and the illumination light source 011 are arranged on the same side of the waveguide, the illumination light beam 012 emitted by the light source is coupled into the waveguide through the first coupling grating 014 of the waveguide and coupled out to the human eye 017 by the first coupling grating 015, and the reflected light 018 of the human eye 017 is received by the detector 019; or, the illumination light beam 012 emitted by the light source irradiates the human eye 017, and the reflected light 018 of the human eye 017 is emitted to the detector 019 through the waveguide.

[0076] Figure 4 In the figure, the illumination light beam 012 emitted by the illumination light source 011 enters the waveguide through refraction and is diffracted by the first coupling-in grating 014, so that the diffracted light propagates in the waveguide in the form of total reflection until the total reflected light 018 hits the first coupling-out grating 015, wherein a portion of the light is coupled out of the waveguide by the first coupling-out light beam 016, corresponding to the first coupling-out light beam 016 (the light schematic diagram here ignores the refraction between the waveguide substrate 013 and the air), a portion of the light continues to be transmitted forward along the total reflection path, hits the first coupling-out grating 015 again, and the above phenomenon is repeated until the entire first coupling-out grating 015 couples out the scattered light, and the total reflected light 018 is transmitted outside the waveguide to form the first coupling-out light beam 016. The first outcoupled light beam 016 irradiates the human eye 017, and forms reflected light 018 after being reflected by the structure of the human eye 017. The reflected light 018 enters the detector 019, and finally the image processor analyzes the reflected image to extract the morphological features of the eye structure, and analyzes the gaze direction, gaze point and other information of the human eye 017 from these features, so as to make more effective feedback.

[0077] Figure 5 for Figure 4 A conjugate illumination method is adopted, that is, the illumination light beam 012 emitted from the illumination light source 011 first illuminates the human eye 017, and the scattered light reflected by the structure of the human eye 017 is refracted into the waveguide substrate 013, and is diffracted by the first coupling optical grating in the waveguide substrate 013. The diffracted light propagates in the waveguide in the form of total reflection until it hits the first coupling grating 015, is coupled out by the first coupling grating 015, and is received by the detector 019. The processor analyzes the light intensity and image information received by the detector 019, extracts the morphological features of the eye structure, and analyzes the gaze direction, gaze point and other information of the human eye 017 from these features, thereby making more effective feedback.

[0078] Optional, such as Figure 6As shown, a reflection coupling-in grating 071 and a reflection coupling-out grating 072 are also provided on the waveguide substrate 013, the first coupling-out grating 015 is stacked with the reflection coupling-in grating 071, the detector 019 is provided on the light-emitting side of the reflection coupling-out grating 072, and the reflected light 018 is coupled into the waveguide substrate 013 by the reflection coupling-in grating 071 and coupled out to the detector 019 by the reflection coupling-out grating 072.

[0079] After being refracted by the waveguide substrate 013, the illumination light beam 012 emitted by the illumination light source 011 is coupled into the first waveguide path by the first coupling grating 014, and is coupled out by the first coupling grating 015 after total reflection propagation, forming a first coupling light beam 016. The first coupling light beam 016 irradiates the human eye 017 and is reflected by the structure of the human eye 017. The reflected light 018 is coupled into the waveguide substrate 013 through the second coupling grating 023 of the second waveguide path, and is coupled out by the second coupling grating 024 of the second waveguide path after total reflection propagation, and finally reaches the detector 019. The processor analyzes the light intensity and image information received by the detector 019, extracts the morphological features of the eye structure, and analyzes the gaze direction, gaze point and other information of the human eye 017 from these features, thereby making more effective feedback.

[0080] In another aspect of the embodiments of the present application, a display device is provided. Figure 7 and Fig. 9 As shown, the eye tracking device includes the above-mentioned eye tracking device, and a second coupling-in grating 023 and a second coupling-out grating 024 arranged on the waveguide of the eye tracking device, the second coupling-in grating 023 is arranged in close contact with the first coupling-in grating 014, the second coupling-out grating 024 is arranged in a stacked manner with the second coupling-out grating 024, and the waveguide is provided with an optical machine 021 corresponding to the second coupling-in grating 023, and the image light beam 022 emitted by the optical machine 021 is coupled into the waveguide by the second coupling-in grating 023 and coupled out by the second coupling-out grating 024 for imaging.

[0081] Specifically, Figure 7 As shown, the eye tracking device is also provided with a second coupling grating 023 and a second coupling grating 024, wherein the waveguide is provided with an optical machine 021 corresponding to the second coupling grating 023, and the second coupling grating 023 is used to couple the image light beam 022 emitted by the optical machine 021 into the waveguide for total reflection propagation, as shown in FIG. Figure 8 As shown by the solid line, the second outcoupling grating 024 is used to couple out the image light beam 022 to form a second outcoupling light beam 025 .

[0082] exist Figure 7 The display device shown has two beam transmission channels, including Figure 8The transmission channel of the illumination light beam 012 for eye tracking is shown by the dotted line in the middle, and the transmission channel of the image light beam 022 is shown by the solid line. The transmission channel of the illumination light beam 012 is as follows: the illumination light beam 012 emitted by the illumination light source 011 enters the waveguide through refraction, and is diffracted by the first coupling-in grating 014, so that the diffracted light propagates in the waveguide in the form of total reflection, until the total reflected light 018 hits the first coupling-out grating 015, wherein a portion of the light is coupled out of the waveguide by the first coupling-out light beam 016, corresponding to the first coupling-out light beam 016 (the light schematic diagram here ignores the refraction between the waveguide and the air), and a portion of the light continues to be transmitted forward along the total reflection path, hits the first coupling-out grating 015 again, and the above phenomenon is repeated until the entire first coupling-out grating 015 couples out the scattered light, and the total reflected light 018 is transmitted outside the waveguide to form the first coupling-out light beam 016. The first outcoupled light beam 016 irradiates the human eye 017, and forms reflected light 018 after being reflected by the structure of the human eye 017. The reflected light 018 enters the detector 019, and finally the image processor analyzes the reflected image to extract the morphological features of the eye structure, and analyzes the gaze direction, gaze point and other information of the human eye 017 from these features, so as to make more effective feedback.

[0083] The transmission channel of the image light beam 022 is as follows: the image light beam 022 emitted by the optical machine 021 enters the waveguide after refraction, and is diffracted by the second coupling-in grating 023, so that the diffracted light propagates in the waveguide in the form of total reflection, until the total reflected light 018 hits the second coupling-out optical grating, wherein a portion of the light is coupled out of the waveguide by the second coupling-out grating 024 and enters the human eye 017 (the light schematic diagram here ignores the refraction between the waveguide and the air), and a portion of the light continues to be transmitted forward along the total reflection path, hits the second coupling-out grating 024 again, and the above phenomenon is repeated until the entire second coupling-out optical grating couples out the image light beam 022, and the total reflected light 018 is transmitted outside the waveguide to form the second coupling-out light beam 025, and the second coupling-out grating 024 forms an image in front of the human eye 017 to achieve display.

[0084] In order to couple light beams of different wavelength bands and facilitate the arrangement of the illumination light beam 012 and the image light beam 022 in space, the first coupling grating 014 and the second coupling grating 023 are arranged side by side and close to each other. The second coupling grating 024 and the second coupling grating 024 are stacked. It should be noted that Figure 7 For the convenience of observation, the first outcoupling grating 015 and the second outcoupling grating 024 are displayed offset in the plane where the waveguide is located.

[0085] In practical applications, in order to improve the field of view of the display device, a first turning grating 041 is set between the first coupling-in grating 014 and the first coupling-out grating 015, and a second turning grating 042 is set between the second coupling-in grating 023 and the second coupling-out grating 024. Fig. 9As shown, the first turning grating 041 and the second turning grating 042 perform pupil expansion on the illumination light beam 012 and the image light beam 022 in the vertical direction respectively. Fig. 9 The optical path diagram in the display device is as follows Fig.10 and Fig.11 As shown, it also has two beam transmission channels, including Fig.10 and Fig.11 The transmission channel of the illumination light beam 012 for eye tracking is shown by the dotted line, and the transmission channel of the image light beam 022 is shown by the solid line. The transmission channel of the illumination light beam 012 is as follows: the illumination light beam 012 emitted by the illumination light source 011 enters the waveguide through refraction, and is diffracted by the first coupling grating 014, so that the diffracted light propagates in the waveguide in the form of total reflection until the total reflection light 018 hits the first turning grating 041, wherein a part of the light is deflected by the first turning grating 041 to the positive direction of the x-axis, and continues to be transmitted to the first coupling grating 015 in the form of total reflection, and the other part of the light continues to be transmitted forward along the original total reflection path. The total reflected light 018 of the decoupling optical element deflects to the first decoupling grating 015, and a part of the light is coupled out of the waveguide by the first decoupling beam 016, corresponding to the first decoupling beam 016 (the light schematic diagram here ignores the refraction between the waveguide and the air), and a part of the light continues to be transmitted forward along the total reflection path, and hits the first decoupling grating 015 again, and the above phenomenon is repeated until the entire first decoupling grating 015 couples out scattered light, and the total reflected light 018 is transmitted outside the waveguide to form the first decoupling beam 016. The first decoupling beam 016 irradiates the human eye 017, and after being reflected by the structure of the human eye 017, it forms the reflected light 018, and the reflected light 018 enters the detector 019, and finally the image processor analyzes the reflected image, extracts the morphological features of the eye structure, and analyzes the gaze direction, gaze point and other information of the human eye 017 from these features, so as to make more effective feedback.

[0086] The transmission channel of the image light beam 022 is as follows: the image light beam 022 emitted by the optical machine 021 enters the waveguide through refraction, and is diffracted by the second coupling-in grating 023, so that the diffracted light propagates in the waveguide in the form of total reflection, until the total reflection light 018 hits the second turning grating 042, wherein a part of the light is deflected to the positive direction of the x-axis by the second turning optical grating, and continues to be transmitted to the second coupling-out grating 024 in the form of total reflection, and the other part of the light continues to be transmitted forward along the original total reflection path, hits the second turning grating 042 again, repeats the above phenomenon, and completes the pupil expansion in the vertical direction; turns to the second coupling-out grating During the transmission process, the totally reflected light 018 of the grating 024 hits the second out-coupling grating 024, wherein a part of the light is coupled out of the waveguide by the second out-coupling grating 024 and enters the human eye 017 (the light schematic diagram here ignores the refraction between the waveguide and the air), and a part of the light continues to be transmitted forward along the totally reflected path and hits the second out-coupling grating 024 again, and the above phenomenon is repeated until the entire second out-coupling optical grating couples out the image light beam 022, and the totally reflected light 018 is transmitted outside the waveguide to form a second out-coupling light beam 025, and the second out-coupling grating 024 forms an image in front of the human eye 017 to achieve display.

[0087] According to the above, the turning grating can also be prepared by using the equivalent exposure theory. Specifically, the equivalent exposure manufacturing conditions of the first turning grating 041 are shown in Table 2:

[0088] Table 2. Equivalent exposure manufacturing conditions for the first turning grating 041

[0089]

[0090] In practical applications, in order to improve the field of view of the display device, the first outcoupling grating 015 and the second outcoupling grating 024 are also set as two-dimensional gratings. Specifically, the two-dimensional first outcoupling grating 015 is a first two-dimensional grating 051, and the two-dimensional second outcoupling grating 024 is a second two-dimensional grating 052. Fig.12 As shown, Fig.12 The optical path diagram in the display device is as follows Fig.13 As shown, it also has two beam transmission channels, including Fig.13The transmission channel of the illumination light beam 012 for eye tracking is shown by the dotted line in the middle, and the transmission channel of the image light beam 022 is shown by the solid line. The transmission channel of the illumination light beam 012 is as follows: the illumination light beam 012 emitted by the illumination light source 011 enters the waveguide through refraction, and is diffracted by the first coupled optical grating, so that the diffracted light propagates in the waveguide in the form of total reflection until the total reflected light 018 hits the first two-dimensional grating 051. In one case, the first two-dimensional grating 051 includes a first sub-turning optical element, a second sub-turning optical element, a first sub-coupling optical element and a second sub-coupling optical element, wherein the first sub-turning optical element and the second sub-turning optical element are respectively used to turn and expand the illumination light beam 012 of the positive and negative fields of view, and the first sub-coupling optical element and the second sub-coupling optical element are respectively used to expand and couple out the illumination light beam 012 of the positive and negative fields of view; in another case, the first two-dimensional grating 051 only includes the first sub-turning optical element and the first sub-coupling optical element, because the field of view of the illumination light beam 012 is determined by the scattering of the coupling optical element, and there is no need to splice the field of view. Therefore, only one turn and one coupling optical element are needed to form the first two-dimensional grating 051 for coupling out the illumination light beam 012. The scattered first coupled light beam 016 coupled out by the first two-dimensional grating 051 irradiates the human eye 017. After being reflected by the structure of the human eye 017, the reflected light 018 enters the detector 019. Finally, the image processor analyzes the reflected image to extract the morphological features of the eye structure, and analyzes the gaze direction, gaze point and other information of the human eye 017 from these features, so as to make more effective feedback.

[0091] The transmission channel of the image light beam 022 is as follows: the image light beam 022 emitted by the optical machine 021 enters the waveguide through refraction, and is diffracted by the first coupling-in grating 014, so that the diffracted light propagates in the waveguide in the form of total reflection until the total reflection light 018 hits the second two-dimensional grating 052. The second two-dimensional grating 052 includes a third sub-bending optical element, a fourth sub-bending optical element, a third sub-coupling optical element, and a fourth sub-coupling optical element, wherein the third sub-bending optical element and the fourth sub-bending optical element are used to bend and expand the image light of the positive and negative fields, respectively, and the third sub-coupling optical element and the fourth sub-coupling optical element are used to expand and couple out the image light beams of the positive and negative fields, respectively, to form a second coupling-out light beam 025, and the second coupling-out light beam 025 reaches the human eye 017 to achieve display.

[0092] According to the above, the turning grating can also be prepared by using the equivalent exposure theory. Specifically, the equivalent exposure manufacturing conditions of the first turning grating 041 are shown in Table 3:

[0093] Table 3. Equivalent exposure manufacturing conditions for the first / second sub-turn optical element

[0094]

[0095] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing an eye tracking device, characterized in that: include: Providing a waveguide substrate, and defining a first coupling-in grating region and a first coupling-out grating region on the waveguide substrate; Based on the equivalent exposure theory, converting the preset exposure parameters of the first coupling-in grating and the first coupling-out grating into spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating and the first coupling-out grating; According to the spatial exposure parameters of the first coupling-in grating and the first coupling-out grating, respectively, a first coupling-in grating and a first coupling-out grating are prepared in the first coupling-in grating region and the first coupling-out grating region of the waveguide substrate to form a waveguide; An eye tracking device is formed by assembling an illumination light source, the waveguide and the detector, so that the illumination light beam emitted by the illumination light source is irradiated to the human eye directly or through the waveguide and is reflected by the human eye, and the detector is used to receive the reflected light of the human eye.

2. The method for preparing an eye tracking device according to claim 1, characterized in that: The preset exposure parameters are: Determine the reference light R1, the signal light S1, and the exposure wavelength λ1 of the reference light and the signal light of the first coupling grating according to the information of the first coupling grating; and calculating the grating vector K1 according to the reference light R1, the signal light S1, and the exposure wavelength λ1 of the reference light and the signal light; The rotation angles of the reference light, the signal light and the waveguide substrate are calculated according to the grating K1.

3. The method for preparing the eye tracking device according to claim 2, characterized in that: The method of converting the preset exposure parameters of the first coupling-in grating and the first coupling-out grating into spatial exposure parameters in the equivalent exposure parameter space of the first coupling-in grating and the first coupling-out grating based on the equivalent exposure theory includes: The reference light, the signal light and the waveguide substrate are rotated at the rotation angle to obtain the rotated reference light R 1-1 , signal light S 1-1 and the location of the waveguide substrate; The exposure wavelength λ1 of the reference light and the signal light is changed to the recording wavelength λ2, and the rotated reference light and the signal light are rotated at least once to obtain the vector R in the exposure material of the reference light. 1-2 And the signal light exposure material vector S 1-2 ; According to the reference light exposure material vector R 1-2 and the vector S in the exposure material of the signal light 1-2 , determine the reference light vector R in air 1-3 and the vector S of the signal light in air 1-3 ; According to the reference light vector R in air 1-3 and the vector S of the signal light in air 1-3 , determine the incident angle of the reference light and the incident angle of the signal light.

4. The method for preparing the eye tracking device according to claim 3, characterized in that: The method of preparing the first coupling-in grating in the first coupling-in grating region according to the spatial parameters of the first coupling-in grating comprises: According to the incident angle of the reference light and the incident angle of the signal light, interference exposure is performed on the corresponding position of the waveguide substrate after rotation to obtain a first coupling grating.

5. The method for preparing an eye tracking device according to claim 4, characterized in that: A volume holographic photosensitive material is formed in the waveguide substrate at positions corresponding to the first coupling-in grating and the first coupling-out grating. The signal light and the reference light are exposed at the volume holographic photosensitive material to form a first coupling-in grating, which is a transmission diffraction grating.

6. The method for preparing an eye tracking device according to claim 4, characterized in that: The signal light and the reference light of the first coupling-in grating are both parallel light; the signal light of the first coupling-out grating is scattered light, and the reference light is parallel light.

7. An eye tracking device, characterized in that: The eye tracking device is prepared by the preparation method of any one of claims 1 to 6, comprising a waveguide, and an illumination light source and a detector respectively arranged at intervals from the waveguide, wherein the illumination light beam emitted by the illumination light source is irradiated to the human eye directly or through the waveguide, and the detector is used to receive the reflected light of the human eye.

8. The eye tracking device according to claim 7, characterized in that: The detector and the illumination light source are arranged on the same side of the waveguide, the illumination light beam emitted by the light source is coupled into the waveguide through the first coupling grating of the waveguide and coupled out to the human eye by the first coupling grating, and the reflected light of the human eye is received by the detector; or, the illumination light beam emitted by the light source is irradiated to the human eye, and the reflected light of the human eye is emitted to the detector through the waveguide.

9. The eye tracking device according to claim 7, characterized in that: A reflection coupling-in grating and a reflection coupling-out grating are also arranged on the waveguide. The first coupling-out grating is stacked with the reflection coupling-in grating. The detector is arranged on the light-emitting side of the reflection coupling-out grating. The reflected light is coupled into the waveguide by the reflection coupling-in grating and coupled out to the detector by the reflection coupling-out grating.

10. A display device, characterized in that: The eye tracking device comprises the eye tracking device according to any one of claims 7 to 9, and a second coupling-in grating and a second coupling-out grating arranged on a waveguide of the eye tracking device, wherein the second coupling-in grating is arranged to fit the first coupling-in grating, and the second coupling-out grating is arranged to be stacked with the second coupling-out grating, and the waveguide is provided with an optical machine corresponding to the second coupling-in grating, and an image light beam emitted by the optical machine is coupled into the waveguide by the second coupling-in grating and coupled out by the second coupling-out grating for imaging.

Images