Optical module, eye camera and eyeball tracking method

Abstract

The invention discloses an optical module, an eye camera and an eyeball tracking method, and the optical module comprises a light modulation element which is used for receiving incident light from a target object and generating a first polarized light signal and a second polarized light signal, the first polarized light signal is orthogonal to the polarization state of the incident light, and the second polarized light signal is orthogonal to the polarization state of the target object; the inner product of the second polarized light signal and the Jones vector of the incident light is larger than 0 or smaller than 0, the light sensor is used for receiving the first polarized light signal and the second polarized light signal to generate data information, and the processor is coupled with the light sensor and used for determining image information of a target object according to the data information. According to the optical module provided by the invention, dual optimization of reflection suppression and detail enhancement in a target recognition scene can be realized, the target object distinction degree is improved, the detail richness of imaging is considered, and the applicability of polarization imaging in a scene with a low signal-to-noise ratio and a high dynamic range is expanded.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to an optical module, an eye camera, and an eye tracking method. Background Art

[0002] Polarization imaging is an optical detection method that records the polarization state of light waves reflected or transmitted by an object and combines this information with the intensity distribution to analyze target features. Unlike traditional intensity imaging, which only records the amplitude of light waves, polarization imaging can accurately extract and analyze the polarization information carried by the object light while acquiring the intensity information. This allows identification of the object's material, internal stress, defects, and other characteristics.

[0003] In target recognition scenarios like eye tracking, existing technologies use polarization imaging to suppress irrelevant reflected signals, significantly improving tracking accuracy and stability. While this improves anti-interference capabilities to some extent, significant drawbacks remain. Firstly, polarization information is susceptible to noise interference due to ambient stray light or multiple scattering from the target surface, resulting in blurred images and a sharp drop in the signal-to-noise ratio, especially in low-light conditions. Secondly, traditional polarization imaging relies on data acquisition at a single wavelength or with limited polarization angles, resulting in the loss of detailed information such as the target's high-frequency texture and microstructure, affecting recognition accuracy. Summary of the Invention

[0004] One of the purposes of the present application is to provide an optical module to solve the technical problems in the prior art of optical modules in target recognition, such as insufficient clarity, difficulty in distinguishing boundaries, and loss of detail information.

[0005] One of the purposes of this application is to provide an eye camera.

[0006] One of the purposes of this application is to provide an eye tracking method.

[0007] To achieve one of the above-mentioned purposes, one embodiment of the present application provides an optical module, including: an optical modulation element, used to receive incident light from a target object, generate a first polarized light signal and a second polarized light signal, the first polarized light signal is orthogonal to the polarization state of the incident light, and the inner product of the second polarized light signal and the Jones vector of the incident light is greater than 0 or less than 0, a light sensor, used to receive the first polarized light signal and the second polarized light signal to generate data information, and a processor, coupled to the light sensor, used to determine image information of the target object based on the data information.

[0008] Optionally, the light modulation element includes a grating structure unit arranged at at least one of the light incident side or the light exit side of the light modulation element, the grating structure unit is used to modulate the polarization state of light, and the grating structure unit is used to form a metasurface.

[0009] Optionally, the optical sensor is used to generate first data information based on the first polarized light signal, the processor is used to generate a first sub-image based on the first data information, the optical sensor is used to generate second data information based on the second polarized light signal, the processor is used to generate a second sub-image based on the second data information, and the processor determines at least one of the contour information, shape information, position information, and posture information of the target object based on the first sub-image and the second sub-image.

[0010] Optionally, the optical modulation element is also used to receive incident light from the target object to generate a third polarized light signal and a fourth polarized light signal, and the optical sensor is used to receive the first polarized light signal, the second polarized light signal, the third polarized light signal and the fourth polarized light signal to generate data information, the first polarized light signal has a linear polarization state at a first angle, the second polarized light signal has a linear polarization state at a second angle, the third polarized light signal has a linear polarization state at a third angle, and the fourth polarized light signal has a linear polarization state at a fourth angle, and the difference between adjacent angles among the first angle, the second angle, the third angle and the fourth angle is 45 degrees.

[0011] Optionally, the light modulation element is used to receive incident light from the target object, and generates n groups of polarized light signals corresponding to n areas of the light sensor. The light sensor is used to receive the n groups of polarized light signals to generate data information. The processor is used to determine image information containing n sub-images based on the data information, and the n sub-images correspond to the n groups of polarized light signals at the n areas.

[0012] Optionally, along the propagation direction of the incident light from the target object, the optical module includes in sequence: a first optical component for converging the incident light from the target object and outputting it to a light modulation element, a light modulation element, a second optical component for focusing the polarized light signal generated by the light modulation element to a light sensor, a light sensor, a processor, the first optical component is configured according to at least one of the following: the first optical component includes a first metalens for converging the incident light, a nanostructure unit is provided at at least one of the light entrance side or the light exit side of the first metalens, and the nanostructure unit is used to form a metasurface, the first optical component includes at least one refractive lens for converging the incident light, the second optical component is configured according to at least one of the following: the second optical component includes a second metalens for focusing the polarized light signal, a nanostructure unit is provided at at least one of the light entrance side or the light exit side of the second metalens, and the nanostructure unit is used to form a metasurface, the second optical component includes a first refractive lens, a second refractive lens, a third refractive lens and a fourth refractive lens for focusing the polarized light signal, the first refractive lens and the third refractive lens are convex lenses, and the second refractive lens and the fourth refractive lens are concave lenses.

[0013] Optionally, according to at least one of the following configurations: the optical module has an effective imaging focal length f, and the light modulating element forms a diffraction angle θ after receiving 0 degree incident lightgrating , f * tan(θ grating ) > 0.5, the size of the light sensor target surface IMGH is greater than 3.4 mm. The optical module further includes a first optical component and a second optical component. The first optical component is used to converge the incident light from the target object and output it to the light modulation element. The second optical component is used to focus the polarized light signal generated by the light modulation element onto the light sensor. The first optical component and the light modulation element as a whole have a first focal length f1, and the second optical component has a second focal length f2, where 30 < f1 / f2 < 90. The optical module further includes a second optical component, which is used to focus the polarized light signal generated by the light modulation element onto the light sensor. The second optical component has a field angle range FOV corresponding to the target surface of the light sensor image , after the light modulation element receives the incident light at 0 degrees, a diffraction angle θ is formed grating , FOV image > 3·θ grating .

[0014] Optionally, the optical module includes a first optical component, a light modulation element, and a second optical component that are integrated. The first optical component is used to converge the incident light from the target object and output it to the light modulation element. The second optical component is used to focus the polarized light signal generated by the light modulation element onto the light sensor. The optical module is configured according to at least one of the following: The optical module has an effective imaging focal length f. After the light modulation element receives the incident light at 0 degrees, a diffraction angle θ is formed grating , 0.2 < f * tan(θ grating ) < 0.4, the size of the light sensor target surface IMGH is greater than 4.4 mm. The first optical component and the light modulation element as a whole have a first focal length f1, and the second optical component has a second focal length f2, where 20 < f1 / f2 < 40. The second optical component has a field angle range FOV corresponding to the target surface of the light sensor image , after the light modulation element receives the incident light at 0 degrees, a diffraction angle θ is formed grating , 1.5 < FOV image / θ grating < 3.

[0015] Optionally, it is configured according to at least one of the following: The optical module further includes an aperture and a second optical component. The aperture is disposed on the light output side of the light modulation element. The second optical component is used to focus the polarized light signal passing through the aperture onto the light sensor. There is a distance d between the light modulation element and the aperture, where 0.04 mm < d < 0.8 mm. The optical module further includes a first optical component, which is used to converge the incident light from the target object and output it to the light modulation element. The first optical component includes at least two refractive lenses. There is a refractive index difference N between any two refractive lenses in the first optical component i -N i+1 , 0.01 < Ni -N i+1 <0.2, the refractive lens in the first optical component has an Abbe number V, 18 < V < 57. The optical module further includes a second optical component for focusing the polarized light signal generated by the light modulation element onto the photosensor. The second optical component includes at least two refractive lenses, and there is a refractive index difference N between any two refractive lenses in the second optical component i -N i+1 , 0.01 < N i -N i+1 <0.2, the refractive lens in the second optical component has an Abbe number V, 18 < V < 57.

[0016] Optionally, the optical module includes a first light modulation element and a second light modulation element. At least one of the incident side or the output side of the first light modulation element is provided with a grating structure unit for modulating the polarization state of light. At least one of the incident side or the output side of the second light modulation element is provided with a nanostructure unit for forming a metasurface

[0017] Optionally, configured according to at least one of the following: The metasurface has an optical effective radius R M , the metasurface has a maximum phase difference Δφ at a single wavelength, 30 < |Δφ / R M | < 50, the metasurface has a working wavelength λ, and the metasurface has a phase related to the working wavelength The metasurface has a focal length f M , the metasurface has a subwavelength structure at a distance r from the center of the metasurface, and this subwavelength structure has a phase N is the phase order, the metasurface has a working wavelength λ, and the metasurface has a phase related to the working wavelength The metasurface has a focal length f M , the metasurface has a subwavelength structure at a distance r from the center of the metasurface, and this subwavelength structure has a phase The metasurface has a working wavelength λ, and the metasurface has a phase related to the working wavelength The metasurface has a focal length f M , the metasurface has a subwavelength structure at a distance r from the center of the metasurface, and this subwavelength structure has a phase

[0018] Optionally, the optical module includes a first optical component, a light modulation element, and a second optical component that are integrated. The first optical component is used to converge the incident light from the target object and output it to the light modulation element. The second optical component is used to focus the polarized light signal generated by the light modulation element onto the photosensor. The metasurface has an optical effective radius R M, the metasurface has a maximum phase difference Δφ at a single wavelength, 50<|Δφ / R M |<750.

[0019] To achieve one of the above-mentioned purposes, one embodiment of the present application provides an eye camera, including an optical module. The eye camera is arranged on the optical path of light emitted from the eyeball to receive incident light from the eyeball. The optical module in the eye camera is configured to use at least one of the eyeball, pupil or reflection point formed by the light source at the eyeball as the target object.

[0020] Optionally, the optical module has an imaging field of view FOV, and the distance between the eye camera and the eyeball is h.

[0021] Optionally, the eye camera is used to determine the current line of sight direction of the eyeball based on the pupil position and the reflection point position, and the reflection point is Purkinje's spot.

[0022] To achieve one of the above-mentioned purposes, the present application provides an eye tracking method, comprising: obtaining image information of the eye according to an optical module or an eye camera, the image information including a first sub-image corresponding to a first polarized light signal and a second sub-image corresponding to a second polarized light signal; and one of the following: determining the pupil position and / or reflection position according to the first sub-image to determine the current line of sight of the eye, and determining the pupil position and / or reflection point position according to the first sub-image and the second sub-image to determine the current line of sight of the eye.

[0023] Optionally, it includes at least one of the following: obtaining a linear superposition image of the first sub-image and the second sub-image, determining the pupil position and / or the reflection point position, determining the current line of sight direction of the eyeball, determining a polarization image based on the first sub-image and the second sub-image, determining the pupil position and / or the reflection point position, determining the current line of sight direction of the eyeball, determining a polarization angle image based on the first sub-image and the second sub-image, determining the pupil position and / or the reflection point position, and determining the current line of sight direction of the eyeball.

[0024] Compared with the prior art, the optical module provided by the present application, by configuring the light modulation element, generates a first polarized light that is orthogonal to the polarization state of the incident light and a second polarized light that is non-orthogonal to the polarization state of the incident light, thereby achieving dual optimization of reflection suppression and detail enhancement in the target recognition scenario. On the one hand, the first polarized light can effectively suppress the mirror reflection of the target surface, reduce the influence of interfering light, thereby enhancing the contrast between the target object and the background, and improving the boundary resolution capability. On the other hand, the non-orthogonal polarized light retains the high-frequency texture and microstructure information in part of the reflected light, making up for the detail loss problem caused by excessive filtering in traditional polarization imaging, making the imaging results more suitable for high-precision recognition (such as eye micro-movement tracking) or complex environments (such as multi-light source interference). In this way, while improving the discrimination of the target object, the richness of the details of the imaging is taken into account, and the applicability of polarization imaging in low signal-to-noise ratio and high dynamic range scenarios is expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of an eye camera in one embodiment of the present application.

[0026] Figure 2 This is a schematic diagram of the cooperation between the eye camera and the eye in one embodiment of the present application.

[0027] Figure 3 Schematic diagram of an optical module in one embodiment of the present application.

[0028] Figure 4 Schematic diagram of a grating structure unit in one embodiment of the present application.

[0029] Figure 5 FIG. 1 is a schematic diagram of the configuration of light modulation elements in one embodiment of the present application.

[0030] Figure 6 Schematic diagram of a light sensor in one embodiment of the present application.

[0031] Figure 7 Schematic diagram of a nanostructure in one embodiment of the present application.

[0032] Figure 8 Schematic diagram of the modulation transfer function in one embodiment of the present application.

[0033] Figure 9 It is a schematic diagram of relative illumination in one embodiment of the present application.

[0034] Figure 10 Schematic diagram of the phase of an optical component in one embodiment of the present application.

[0035] Figure 11 FIG. 1 is a schematic diagram of the phase of the light modulation element in one embodiment of the present application.

[0036] Figure 12 This is a schematic diagram of imaging of a target object in one embodiment of the present application.

[0037] Figure 13 This is a schematic diagram of imaging of another target object in one embodiment of the present application.

[0038] Figure 14 Schematic diagram of a compact optical module in one embodiment of the present application.

[0039] Figure 15 Schematic diagram of the modulation transfer function in a compact configuration in one embodiment of the present application.

[0040] Figure 16 Schematic diagram of relative illumination in a compact configuration according to one embodiment of the present application.

[0041] Figure 17 Schematic diagram of the phase of the first optical component in a compact configuration in one embodiment of the present application.

[0042] Figure 18 FIG. 1 is a schematic diagram illustrating the phase of a light modulating element in a compact configuration according to an embodiment of the present application.

[0043] Figure 19 Schematic diagram of the phase of the second optical component in a compact configuration in one embodiment of the present application.

[0044] Figure 20 It is a schematic diagram of an optical module package in one embodiment of the present application.

[0045] Figure 21 It is a schematic diagram of an optical module package in one embodiment of the present application.

[0046] Figure 22 Schematic diagram of an eye tracking method in one embodiment of the present application.

[0047] Figure 23 yes Figure 12 and Figure 13 Schematic diagram of the linear overlay image in (b).

[0048] Figure 24 yes Figure 12 Schematic diagram of the polarization degree image and polarization angle image in (b).

[0049] Figure 25 yes Figure 13 Schematic diagram of the polarization degree image and polarization angle image in (b).

[0050] Figure 26 It is a schematic diagram of image information obtained by executing an embodiment of the present application. DETAILED DESCRIPTION

[0051] The present application will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are included within the scope of protection of the present application.

[0052] It should be noted that the term "comprise" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0053] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first," "second," and "third," etc., are not necessarily related to each other; for example, the inclusion of "second" in an embodiment of this application does not necessarily mean that the embodiment also includes "first," and so on.

[0054] Eye camera

[0055] An embodiment of the present application provides an eye camera 1000, such as Figure 1 shown.

[0056] The eye camera 1000 may include the optical module 100 described below, and the eye camera 1000 may also be the optical module 100 .

[0057] The eye camera 1000 can measure at least one of the eye movement trajectory, line of sight direction, gaze point position or pupil change through the optical module 100.

[0058] The eye camera 1000 can measure the state of the eyeball based on at least one of the pupil-corneal reflection method (PCCR), retinal imaging, structured light method, MEMS (Micro-Electro-Mechanical System) scanning or optical waveguide method.

[0059] Among them, PCCR mainly calculates the direction of sight by analyzing the relative position changes between the pupil center and the corneal reflection point.

[0060] In one embodiment, PCCR may specifically include: using near-infrared light to illuminate the eyeball, forming a reflected light spot (Purkinje spot) on the corneal surface, and the pupil correspondingly presenting a high-contrast dark area ("dark pupil") or bright area ("bright pupil"); using the eye camera 1000 to capture the eyeball image, locate the coordinates of the pupil center and the corneal reflected light spot, calculate the vector between the two (P-CR vector), and map it to the actual gaze point in combination with the calibration model.

[0061] The position of the Purkinje spot is relatively stable and unaffected by pupil dilation. Distinguishing between dark areas ("dark pupil") and bright areas ("bright pupil") facilitates image recognition. There are physiological differences between the visual axis (actual line of sight) and the optical axis (the line connecting the pupil and corneal reflection). In some embodiments, personalized calibration can compensate for these differences.

[0062] The eye camera 1000 provided in this application includes an optical module 100 .

[0063] The optical module 100 includes a light modulator 11. The light modulator 11 is configured to receive incident light from an object OBJ and generate a first polarized light signal and a second polarized light signal. The first polarized light signal is orthogonal to the polarization state of the incident light, and the inner product of the second polarized light signal and the Jones vector of the incident light is greater than or less than zero.

[0064] The optical module 100 includes a light sensor 12. The light sensor 12 is configured to receive a first polarized light signal and a second polarized light signal to generate data information.

[0065] The optical module 100 includes a processor 13. The processor 13 is coupled to the optical sensor 12. The processor 13 is configured to determine image information of the target object OBJ according to data information.

[0066] The eye camera 1000 is disposed on the optical path of light emitted from the eyeball to receive incident light from the eyeball.

[0067] The incident light from the eyeball may be light reflected from the eyeball. The eye camera 1000 or an eye tracking system including the eye camera 1000 may further include a light source for illuminating the eyeball. The light output by the light source is reflected by the eyeball and received by the eye camera 1000. The light source may be configured to output infrared light or laser light.

[0068] The optical module in the eye camera 1000 is configured to use at least one of the eyeball, the pupil, or a reflection point formed by a light source on the eyeball as the target object OBJ.

[0069] The eye camera 1000 can be configured to face the eyeball and be oriented parallel or non-parallel to the optical axis or visual axis of the eyeball. The light source emits light toward the eyeball, and the eye camera 1000 receives at least part of the light reflected by the eyeball to obtain an image of the eye.

[0070] A polarizing plate or other structure may be provided at the light source, or between the light source and the eyeball, so that the polarization states of the incident light from the eyeball and at least one of the polarized lights generated by the light modulator 11 are orthogonal, and the Jones vector inner product of the incident light from the eyeball and at least another of the polarized lights generated by the light modulator 11 is greater than 0 or less than 0.

[0071] The light source may include an infrared light emitting diode; the eye camera 1000 may also be an infrared camera.

[0072] In one embodiment, the light source may include at least one of a VCSEL (Vertical-Cavity Surface-Emitting Laser), a fiber laser, and an EEL (Edge-Emitting Laser).

[0073] Eye camera 1000 can be used to implement at least one of virtual reality (VR), augmented reality (AR), and mixed reality (MR). Specifically, it can be used to build closed head-mounted displays, mobile phones, transparent glasses, etc. Eye camera 1000 can also be used to build eye trackers, medical assistance equipment, or in-vehicle driver monitoring systems (DMS).

[0074] The eye camera 1000 or the optical module 100 therein provided in the present application has at least one of the following advantages.

[0075] First, it has strong anti-interference capabilities. For example, based on polarization technology, it can achieve ambient light suppression (signal-to-noise ratio increased by 20dB) and eliminate mirror reflections (corneal reflectivity reduced from 4% to 0.5%). For example, it can work stably in low illumination of 10lux, without the need for high-power infrared fill light (traditionally requires >50lux). For example, it can effectively eliminate eyeglass reflections (resin lens reflectivity 4% → 0.5%) and is compatible with users with dark irises.

[0076] Second, it facilitates three-dimensional dynamic tracking. For example, the birefringence characteristics of the cornea (delay of approximately 50nm) are used to establish a 3D eye orientation model, breaking through the limitations of traditional 2D positioning. For example, dynamic calibration is achieved by combining the polarization characteristics of the tear film (thickness 3-7μm), supporting microsaccade detection (accuracy of up to 0.01°), and providing quantitative indicators for pathological monitoring such as glaucoma and dry eye.

[0077] Third, the hardware system is innovated and optimized. For example, optical elements can be realized as millimeter-level monolithic elements. Combined with variable period design and anti-reflection film technology, the field of view angle expansion and zero-order diffraction suppression can be achieved. The thickness of the imaging module is controlled within 7mm, which is 90% smaller than the traditional multi-camera system. For example, the diffraction efficiency is improved, and the high-order diffraction and small period design are combined to solve the problem of uneven spot intensity under large field of view / large NA conditions (the efficiency of traditional solutions decreases by about 30%). For example, the production process can be simplified and the yield rate is significantly improved.

[0078] Fourth, it offers a wider range of application scenarios. For example, in healthcare, it can simultaneously monitor health conditions such as corneal stress and intraocular pressure changes with high-precision interaction, breaking through the traditional scenario separation. For example, it can capture full polarization state information at once, achieving millisecond-level real-time tracking compared to traditional solutions that require rotating polarizers (with a delay of approximately 200ms).

[0079] Compared with traditional technical solutions, it can also customize optical parameters to specifically match the corneal birefringence characteristics (50nm delay) and tear film dynamics (3-7μm thickness).

[0080] In one embodiment, the reflection point is a Purkinje spot. Purkinje spots are four primary reflection images (Purkinje Images I-IV) formed by light reflecting off different optical surfaces of the eye (e.g., the cornea and lens). The eye camera 1000 can determine the current line of sight of the eye using Purkinje Image I (reflection from the front surface of the cornea) and Purkinje Image IV (reflection from the back surface of the lens).

[0081] Specifically, the eye camera 1000 can establish a mathematical model of gaze direction based on the positional movement of Purkinje I and IV with eye rotation by detecting their positional changes relative to the pupil center or iris. Because Purkinje's spots are physically bound to the eyeball, their relative positional relationship provides a stable baseline for gaze calculation even with head movement. Furthermore, compared to simply tracking the pupil, Purkinje's spots (especially Purkinje IV) are less affected by changes in ambient light and are therefore suitable for complex lighting scenarios.

[0082] In one embodiment, the light source used with the eye camera 1000 can use a specific wavelength (such as 940nm infrared light) to optimize Purkinje spot detection and reduce ambient light interference.

[0083] In one embodiment, the eye camera 1000 can detect Purkinje I and IV simultaneously, combined with pupil center or iris features, to improve the robustness of gaze calculation.

[0084] The eye camera 1000 is used to determine the current line of sight of the eyeball based on the pupil position and the reflection point position.

[0085] In one embodiment, the center of corneal curvature C can be determined based on three-dimensional triangulation of the reflection point, and used as the position of the reflection point. The vector between the two is calculated to form the optical axis vector.

[0086] In one embodiment, a specific parameter of the eyeball can be measured based on a nine-point calibration method as an offset to calibrate the visual axis. The offset can be set to a 5° nasal offset.

[0087] In one embodiment, the reflection points may be used to form a reference coordinate system to calculate the head translation matrix or rotation matrix in real time, and the line of sight coordinate system may be kept stable through coordinate transformation.

[0088] In one embodiment, Figure 2 As shown, the optical module 100 has an imaging field of view FOV, and the distance between the eye camera 1000 and the eyeball is h. The imaging field of view FOV and the distance h can satisfy: Based on the fact that the longitudinal width of the part of the eyeball exposed to the outside is usually 2 cm, or the range of the eyeball required to be detected for tracking the line of sight can be 2 cm, therefore, the eyeball camera 1000 or the optical module 100 that satisfies the above relationship can cover most areas of the eyeball and better realize eye tracking.

[0089] Based on the above relationship, when the distance h between the eye camera 1000 and the eyeball is fixed, the imaging field of view FOV of the optical module 100 can be adjusted to better perform eye tracking; correspondingly, when the imaging field of view FOV of the optical module 100 is fixed, the distance h between the eye camera 1000 and the eyeball can be adjusted to better perform eye tracking.

[0090] When the eye camera 1000 is mounted in a device such as a head-mounted display or smart glasses, the imaging field of view FOV can be 60 degrees, 65 degrees, 70 degrees, 75 degrees, or a larger value.

[0091] Optical module

[0092] An embodiment of the present application provides an optical module 100, such as Figure 3 shown.

[0093] The optical module 100 includes a light modulation element 11 .

[0094] The light modulation element 11 is configured to receive incident light from the object OBJ.

[0095] When the optical module 100 is used to implement eye tracking, the target object OBJ may be a specific part of the eye.

[0096] The incident light from the target object OBJ may be light reflected, refracted, or transmitted from the target object OBJ. The incident light may at least reflect features of the target object OBJ.

[0097] The light modulation element 11 is used to generate a first polarized light signal. The first polarized light signal is orthogonal to the polarization state of the incident light.

[0098] On the one hand, the polarization state of the incident light can be generated by arranging a modulation element such as a polarizer between the light source and the target object OBJ, or by arranging a modulation element such as a polarizer at the light source.

[0099] On the other hand, when the incident light is in a linear polarization state, the first polarized light signal may be another linear polarization state perpendicular to the polarization direction of the incident light. When the incident light is in an elliptically polarized state, the first polarized light signal may be another elliptically polarized state having a principal axis perpendicular to the principal axis of the elliptically polarized state, or another elliptically polarized state having a handedness opposite to that of the elliptically polarized state (for example, left-handedness is opposite to right-handedness). When the incident light is in a circular polarization state, the first polarized light signal may be another circular polarization state having a handedness opposite to that of the circular polarization state. Alternatively, the inner product of the Jones vector of the incident light and the Jones vector of the first polarized light signal is equal to 0.

[0100] The optical modulation element 11 is configured to generate a second polarized light signal. In one embodiment, the inner product of the second polarized light signal and the Jones vector of the incident light is greater than zero. In another embodiment, the inner product of the second polarized light signal and the Jones vector of the incident light is less than zero. The inner product of the second polarized light signal and the Jones vector of the incident light is not equal to zero. The polarization state of the second polarized light signal is non-orthogonal to that of the incident light.

[0101] In this way, based on the fact that the polarization state of the first polarized light signal is orthogonal to the polarization state of the incident light, irrelevant reflection signals (for example, reflections from glasses) can be effectively suppressed, thereby achieving the effect of separating mirror reflections from pupil textures and improving anti-interference capabilities; combined with the fact that the second polarization state and the polarization state of the incident light have the above-mentioned Jones vector relationship, it is possible to prevent the loss of details due to excessive filtering of the information of the incident light signal in the first polarized light signal, and retain more information for feature detection of the target object OBJ.

[0102] The optical module 100 includes a light sensor 12 .

[0103] The optical sensor 12 is used to receive the first polarized light signal and the second polarized light signal and generate data information accordingly.

[0104] The light sensor 12 may be a CMOS (Complementary Metal Oxide Semiconductor) photosensitive element (CIS), a CCD (Charge Coupled Device) photosensitive element or an array photodetector.

[0105] In some embodiments, a high-speed SPAD (Single Photon Avalanche Diode) sensor can be used to detect microsecond eye movements with a frame rate of ≥240fps. In some embodiments, the light sensor 12 can also be integrated with an ALS (Ambient Light Sensor) to automatically adjust exposure parameters.

[0106] In some embodiments, the optical sensor 12 may generate a voltage signal or a current signal related to the polarization state and convert the signal into a digital signal.

[0107] The optical module 100 includes a processor 13 . The processor 13 is coupled to the optical sensor 12 .

[0108] The processor 13 is configured to determine image information of the target object OBJ according to the data information.

[0109] In some embodiments, the processor 13 may be configured as an embedded processor or an image signal processor. In some embodiments, the processor 13 may construct a neural network model during operation to determine image information of the target object OBJ.

[0110] The image information may be an image representing at least part of the features of the target object OBJ, or feature information of the target object OBJ. For example, in a gaze tracking scenario, the image information may be an image of the eye, or a calculated gaze direction.

[0111] Light modulation element

[0112] In one embodiment, the light modulation element 11 is provided as a whole.

[0113] like Figure 4 As shown, in one embodiment, the light modulator 11 includes a grating structure unit Pg arranged on the light incident side of the light modulator 11; in a specific embodiment, the light modulator 11 includes a grating structure unit Pg arranged on the light emitting side; in a specific embodiment, the light modulator 11 is provided with a grating structure unit Pg on both the light incident side and the light emitting side.

[0114] The light incident side of the light modulator 11 may be the surface of the light modulator 11 close to the target object OBJ; the light emitting side of the light modulator 11 may be the surface of the light modulator 11 close to the light sensor 12 .

[0115] In a specific embodiment, the grating structure unit is used to modulate the polarization state of light.

[0116] The grating structure unit can modulate natural light into polarized light, modulate one polarized light into another polarized light, or separate different polarized lights. The grating structure can achieve wavefront shaping or modulation of the polarization state of light through the configuration of its own shape, posture, geometric phase, and propagation phase.

[0117] The grating structure unit can be formed by etching on the surface of the light modulation element 11 .

[0118] In a specific embodiment, the grating structure units are used to form a metasurface. The grating structure units are arranged with a preset metasurface phase to form the metasurface. In the formed metasurface, the grating structure units are arranged with a phase formed by superimposing their own phase and the metasurface phase.

[0119] A metasurface is a two-dimensional subwavelength structure array. In this embodiment, the metasurface composed of grating structure units can achieve precise control of the amplitude, phase, and polarization state of the incident light, realize vector-level polarization control, and reduce the volume to achieve high integration.

[0120] The metasurface formed by the grating structure unit can be configured with reference to Chinese patent applications No. 202311139934.9, 202311140629.1 and 202311139940.4. Figure 5 As shown, the phase of the grating structure unit Pg for polarization modulation is linearly superimposed with the phase of the preset metasurface nanostructure unit Pm to obtain the overall phase of the updated grating structure unit Pmg. In this case, the optical modulation element 11 can have other functions such as multi-focus in addition to the polarization modulation function.

[0121] In one embodiment, the light modulation element 11 is composed of two parts. For example, the optical module 100 includes a first light modulation element and a second light modulation element.

[0122] In one embodiment, a grating structure unit Pg is provided on the light incident side of the first light modulator, or a grating structure unit Pg is provided on the light output side of the first light modulator, or a grating structure unit Pg is provided on both the light incident side and the light output side of the first light modulator.

[0123] The grating structure units Pg are used to modulate the polarization state of light. The grating structure units Pg are arranged periodically.

[0124] In a specific embodiment, a nanostructure unit Pm is provided on the light incident side of the second light modulation element, or a nanostructure unit Pm is provided on the light output side of the second light modulation element, or a nanostructure unit Pm is provided on both the light incident side and the light output side of the second light modulation element.

[0125] The nanostructure units Pm are used to form a metasurface. The nanostructure units Pm are arranged according to a preset metasurface phase to form a metasurface.

[0126] Compared with the embodiment in which the light modulation element 11 is provided as a whole, in this embodiment, the grating structure unit Pg for modulating the polarization state and the nanostructure unit Pm for realizing functions such as multi-focal focusing are respectively provided at two light modulation elements.

[0127] For the embodiments provided in the present application, the nanostructure units Pm or grating structure units Pg arranged with a preset metasurface phase, or the nanostructure units or grating structure units arranged with a superimposed phase, can be collectively referred to as subwavelength structures because they are used to form a metasurface.

[0128] Based on this, for the device parts formed with the metasurface in the present application, such as the metasurface formed based on the grating structure unit Pmg in the optical modulator, or the metasurface formed based on the nanostructure unit Pm in the second optical modulator, or the metalens in the first optical component and the second optical component mentioned later (including the metasurface formed by the nanostructure unit), they can all be configured according to the following embodiments.

[0129] In one embodiment, the metasurface has an optical effective radius R M , the metasurface has a maximum phase difference Δφ at a single wavelength, 30<|Δφ / R M |<50.

[0130] At a single wavelength, different locations in the metasurface generally provide different phases. The metasurface configured according to this embodiment has a better phase matching effect and can more fully utilize the optical performance of the metasurface.

[0131] Preferably, |Δφ / R M |=320.

[0132] In one embodiment, the metasurface has an operating wavelength λ, and the metasurface has a phase The metasurface has a focal length f M , the metasurface has a subwavelength structure with a distance r from the center of the metasurface, and the subwavelength structure has a phase N is the phase order.

[0133] In one embodiment, the metasurface has an operating wavelength λ, and the metasurface has a phase The metasurface has a focal length f M , the metasurface has a subwavelength structure with a distance r from the center of the metasurface, and the subwavelength structure has a phase

[0134] In one embodiment, the metasurface has an operating wavelength λ, and the metasurface has a phase The metasurface has a focal length f M , the metasurface has a subwavelength structure with a distance r from the center of the metasurface, and the subwavelength structure has a phase

[0135] The metasurface configured according to the above embodiments has better light modulation performance.

[0136] Light sensor and processor

[0137] In one embodiment, the light sensor 12 is configured to generate first data information according to the first polarized light signal, and the processor 13 is configured to generate a first sub-image according to the first data information.

[0138] In one embodiment, the light sensor 12 is configured to generate second data information according to the second polarized light signal, and the processor 13 is configured to generate a second sub-image according to the second data information.

[0139] In one embodiment, the processor 13 determines at least one of the contour information, shape information, position information, and posture information of the target object OBJ according to the first sub-image and the second sub-image.

[0140] The image information of the target object OBJ may include a first sub-image and a second sub-image. In the image information, the first sub-image and the second sub-image may overlap in the same area or be displayed separately in different areas.

[0141] The distribution of the first sub-image and the second sub-image in the image information generated by the processor 13 may be the same as the distribution of the first polarized light signal and the second polarized light signal on the target surface of the optical sensor 12. Figure 6 As shown, the first polarized light signal Im1 corresponding to the first sub-image is located in the first area of ​​the optical sensor 12, and the second polarized light signal Im2 corresponding to the second sub-image is located in the second area of ​​the optical sensor 12. The two can be arranged in the horizontal or vertical direction, or in the diagonal direction of the target surface of the optical sensor 12.

[0142] Preferably, by configuring the parameters of the optical module 100, the first polarized light signal Im1 and the second polarized light signal Im2 can be arranged with a maximum area not exceeding the target surface of the light sensor 12, so that the first sub-image and the second sub-image have a maximum area not exceeding the image boundary in the image information.

[0143] In one embodiment, multiple polarized light signals can be generated. Polarized light signals in the multiple polarized light signals that are non-orthogonal to the polarization state of the incident light can be used to supplement image information for details lost due to extinction. Polarized light signals in the multiple polarized light signals that are different from the first polarized light signal can be different from each other.

[0144] In one embodiment, the light modulation element 11 is further configured to receive incident light from the target object OBJ and generate a third polarized light signal and a fourth polarized light signal.

[0145] In one embodiment, the optical sensor 12 is configured to receive a first polarized light signal, a second polarized light signal, a third polarized light signal, and a fourth polarized light signal to generate data information.

[0146] In one embodiment, the first polarized light signal has a linear polarization state at a first angle, the second polarized light signal has a linear polarization state at a second angle, the third polarized light signal has a linear polarization state at a third angle, and the fourth polarized light signal has a linear polarization state at a fourth angle.

[0147] In one embodiment, the difference between adjacent angles among the first angle, the second angle, the third angle and the fourth angle is 45 degrees.

[0148] In this way, the optical modulator 11 is equivalent to generating four commonly used linearly polarized light signals. When the incident light is one of the commonly used linearly polarized light signals, the polarized light signals generated by the optical modulator 11 will inevitably include a polarized light signal orthogonal to the polarization state of the incident light, and will inevitably include a polarized light signal whose polarization state conforms to the aforementioned Jones matrix relationship with the incident light. Therefore, the optical module 100 prepared according to this embodiment has universal applicability and a simple structure.

[0149] Preferably, the first angle is 0 degrees, the second angle is 45 degrees, the third angle is 90 degrees, and the fourth angle is 135 degrees.

[0150] Preferably, if Figure 6 As shown, the first polarized light signal Im1 corresponding to the first sub-image is located in the first area of ​​the light sensor 12, the second polarized light signal Im2 corresponding to the second sub-image is located in the second area of ​​the light sensor 12, the third polarized light signal Im3 corresponding to the third sub-image is located in the third area of ​​the light sensor 12, and the fourth polarized light signal Im4 corresponding to the fourth sub-image is located in the fourth area of ​​the light sensor 12.

[0151] Preferably, the first polarized light signal Im1, the second polarized light signal Im2, the third polarized light signal Im3, and the fourth polarized light signal Im4 are arranged with a maximum area not exceeding the target surface of the light sensor 12; the first sub-image, the second sub-image, the third sub-image, and the fourth sub-image have a maximum area not exceeding the image boundary in the image information.

[0152] In one embodiment, the light modulation element 11 is configured to receive incident light from the target object OBJ and generate n groups of polarized light signals corresponding to n regions of the light sensor 12 .

[0153] n can be a positive integer greater than or equal to 1.

[0154] In one embodiment, the optical sensor 12 is configured to receive n groups of polarized light signals to generate data information.

[0155] In one embodiment, the processor 13 is configured to determine image information including n sub-images according to the data information, where the n sub-images correspond to n groups of polarized light signals at n regions.

[0156] The n groups of polarized light signals arranged in the n regions of the optical sensor 12 are processed by the optical sensor 12 and the processor 13 to present n sub-images arranged in the n regions in the image information. There is a corresponding relationship in position and distribution between the n sub-images and the n groups of polarized light signals.

[0157] The optical sensor 12 can specifically generate n groups of data information based on the n groups of polarized light signals, and the processor 13 can specifically determine n sub-images based on the n groups of data information to form image information.

[0158] Figure 6 The arrangement of the polarized light signals on the optical sensor 12 shown may be a specific embodiment of the present embodiment when n=4.

[0159] Preferably, the light modulation element 11 generates four polarized light signals based on its grating structure unit itself, and focuses the four polarized light signals to different areas of the light sensor 12 based on the metasurface formed by its grating structure unit in a metasurface phase arrangement.

[0160] Image information related configuration

[0161] For the optical module 100 or the eye camera 1000 in any of the above technical solutions, it can be configured according to at least one of the following embodiments to improve the relevant imaging performance.

[0162] In one embodiment, the optical module 100 has an effective imaging focal length f, and the light modulating element 11 forms a diffraction angle θ after receiving a 0-degree incident light. grating . Effective imaging focal length f and diffraction angle θ gratingIt can satisfy: f * tan(θ grating ) > 0.5. Thus, through the cooperative design of the imaging focal length of the light modulation element 11 and the optical module 100, the center of the sub-image generated by the polarized light signal is shifted to a preset optimal range, ensuring that n (for example, 4) sub-images do not overlap with each other and occupy the largest area.

[0163] Preferably, f * tan(θ grating ) = 0.88.

[0164] In one embodiment, the size IMGH of the target surface of the light sensor 12 is greater than 3.4 mm.

[0165] The size of the target surface may be the length of the diagonal of the target surface of the light sensor 12. Thus, it can be ensured that the optical module 100 has a sufficiently large image surface and the number of pixels, for example, enabling the sub-image to have a sufficient number of pixels.

[0166] In one embodiment, the optical module 100 further includes a first optical component 21. The first optical component 21 is used to converge the incident light from the target object OBJ and output it to the light modulation element 11. The optical module 100 further includes a second optical component 22. The second optical component 22 is used to focus the polarized light signal generated by the light modulation element 11 to the light sensor 12. The first optical component 21 and the light modulation element 11 as a whole have a first focal length f1, and the second optical component 22 has a second focal length f2. The first focal length f1 and the second focal length f2 can satisfy: 30 < f1 / f2 < 90. Thus, by restricting the ratio of the first focal length f1 and the second focal length f2, the optical module 100 can image at a preset area on the target surface of the light sensor 12 after passing through the first optical component 21, the light modulator 11, and the second optical component 22 at a relatively large incident angle (for example, an incident angle of 70 degrees), and ensure that the area of the circle projected by the polarized light signal on the target surface of the light sensor 12 reaches the maximum on the premise of non-interference and not exceeding the range of the target surface of the light sensor 12; ensure that the area of the circular sub-image corresponding to the polarized light signal reaches the maximum on the premise of non-interference and not exceeding the display screen of the image information.

[0167] Preferably, f1 / f2 = 30.6.

[0168] In one embodiment, the optical module 100 further includes a second optical component 22. The second optical component is used to focus the polarized light signal generated by the light modulation element to the light sensor. The second optical component has a field angle range FOV corresponding to the target surface of the light sensor image , and the light modulation element forms a diffraction angle θ after receiving the incident light of 0 degrees grating , FOV image > 3·θ grating . Thus, by restricting the field angle range FOVimage and the diffraction angle θ grating to shift the polarized light signal to an appropriate position on the target surface of the optical sensor 12 and shift the sub-image to an appropriate position in the display screen of the image information.

[0169] Correspondingly, if the above relationship is not satisfied, when the diffraction angle θ grating is small, the coverage range of the polarized light signal on the target surface of the optical sensor 12 will not extend to a position close to the edge of the target surface, and the sub-image will not extend to a position close to the edge of the display screen in the display screen of the image information, resulting in too small an area and too few pixels of the sub-image, not meeting the display requirements. When the diffraction angle θ grating is large, the coverage range of the polarized light signal will exceed the edge of the target surface of the optical sensor 12, and the sub-image will exceed the edge of the display screen of the image information, resulting in information loss.

[0170] Preferably, FOV image = 3.75·θ grating .

[0171] Module performance related configurations

[0172] For the optical module 100 or the eye camera 1000 in any of the above technical solutions, it can be configured according to at least one of the following embodiments to improve the related imaging performance.

[0173] In one embodiment, the optical module 100 further includes an aperture. The aperture is disposed on the light output side of the light modulation element 11. The optical module 100 further includes a second optical component 22. The second optical component 22 is configured to focus the polarized light signal passing through the aperture to the optical sensor 12. There is a distance d between the light modulation element 11 and the aperture. The distance d satisfies: 0.04 mm < d < 0.8 mm. Thus, by restricting the distance d, it affects the assembly process between the light modulation element 11 and the second optical component 22, affects the total length of the optical module 100, and affects the size of the vignetting generated by the polarized light signal output by the incident light in each direction and field of view passing through the aperture after passing through the light modulation element 11.

[0174] The aperture may be disposed between the light modulation element 11 and the second optical component 22. In other embodiments, the aperture may be disposed between the light modulation element 11 and the optical sensor 12.

[0175] When the value of the distance d is about 0.04 mm, the optical modulation element 11 and the second optical component 22 can be assembled using the same lens barrel structure to minimize the total length of the optical module 100, which is beneficial to the miniaturized design of the size of the optical module 100. Moreover, the vignetting generated when the polarized light signal output by the optical modulation element 11 passes through the aperture will reach a relatively minimum amount, minimizing the loss on the transmission path of the polarized light signal.

[0176] When the value of the distance d is about 0.08 mm, after the optical modulation element 11 and the second optical component 22 are respectively assembled using two lens barrel structures and then the two lens barrels are assembled by dispensing glue, the total length of the optical module 100 will be larger, and the vignetting generated when the polarized light signal corresponding to the incident light in the outer field of view passes through the aperture will increase. For this case, in one embodiment, the aperture of the optical modulation element 11 can be reduced to weaken the vignetting to avoid uneven brightness of the upper and lower parts of the sub-image itself.

[0177] Preferably, d = 0.15 mm.

[0178] In one embodiment, the optical module 100 further includes a first optical component 21. The first optical component 21 is configured to converge the incident light from the target object OBJ and output it to the optical modulation element 11. The first optical component 21 includes at least two refractive lenses. There is a refractive index difference N i -N i+1 . The refractive index difference satisfies: 0.01 < N i -N i+1 < 0.2. The refractive lenses in the first optical component 21 have an Abbe number V. The Abbe number satisfies: 18 < V < 57. In this way, the volume of the first optical component 21 can be reduced, realizing the miniaturized design of the optical module 100.

[0179] Specifically, the refractive lenses included in the first optical component 21 can be made of plastic material.

[0180] In one embodiment, the optical module 100 further includes a second optical component 22. The second optical component 22 is configured to focus the polarized light signal generated by the optical modulation element 11 to the photosensor 12. The second optical component 22 includes at least two refractive lenses. There is a refractive index difference N i -N i+1 . The refractive index difference satisfies: 0.01 < N i -N i+1 < 0.2. The refractive lenses in the second optical component 22 have an Abbe number V. The Abbe number satisfies: 18 < V < 57.

[0181] Specifically, the refractive lens included in the second optical component 22 may be made of plastic material.

[0182] The following combination Figure 3 A complete introduction to the preferred embodiments of this application.

[0183] Along the propagation direction of the incident light from the target object OBJ, the optical module 100 provided in the present application includes a first optical component 21, a light modulation element 11, a second optical component 22, a light sensor 12 and a processor 13 in sequence.

[0184] The first optical component 21 is used to converge the incident light from the target object OBJ and output the light to the light modulation element 11 .

[0185] The second optical component 22 is used to focus the polarized light signal generated by the light modulation element 11 onto the light sensor 12 .

[0186] A metasurface may be formed at at least one of the first optical component 21 , the second optical component 22 and the light modulation element 11 .

[0187] In one embodiment, when the grating structure units in the optical modulator 11 form a metasurface, and the first optical component 21 and / or the second optical component 22 are composed of a refractive lens, the optical module 100 constitutes a "refractive-metasurface system" that combines "refractive and metasurfaces". This system can meet the requirements of a large field of view in application scenarios such as eye tracking, solve the problem that the metasurface (especially the metasurface composed of grating structure units) is sensitive to incident light at large incident angles, and avoid affecting the polarization extinction ratio and imaging efficiency.

[0188] In one embodiment, the first optical component 21 achieves light convergence through a metasurface.

[0189] In a specific embodiment, the first optical component 21 includes a first metalens for converging incident light. A nanostructure unit is provided on at least one of the light entrance side or the light exit side of the first metalens. The nanostructure unit is used to form a metasurface.

[0190] Combine Figure 7 As shown, the first metalens includes a base layer sub and a nanostructure cell for forming a metasurface. The base layer sub and the nanostructure cell are configured to allow radiation within a preset operating band of the optical module 100. In some embodiments, a cover layer sup is provided outside the nanostructure cell.

[0191] In one embodiment, the thickness of the first super lens is greater than 0.2 mm; in one embodiment, the thickness of the first super lens is less than 0.8 mm.

[0192] In one embodiment, the thickness of the cover layer sup is 2 μm. In one embodiment, the thickness of the base layer sub is 500 μm.

[0193] In one embodiment, the first optical component 21 achieves light convergence through a refractive lens.

[0194] In a specific embodiment, the first optical component 21 includes at least one refractive lens for converging incident light.

[0195] In any of the above embodiments, the first optical assembly 21 is capable of converging incident light within a viewing angle range that matches the application scenario of the optical module 100 to the subsequent stage of the optical module 100, where it is processed by the light modulator 11 to generate a first polarization signal and a second polarization signal. When the optical module 100 is used in an eye-tracking scenario, the viewing angle range can be 70 degrees.

[0196] In one embodiment, the optical module 100 further includes a filter 20 disposed between the first optical component 21 and the light modulator 11. In one embodiment, the optical module 100 may include the filter 20 disposed on a side of the light modulator 11 close to the target object OBJ.

[0197] The optical filter 20 can be prepared based on a metasurface or by a traditional coating method.

[0198] In one embodiment, the second optical component 22 achieves focusing via a metasurface.

[0199] In a specific embodiment, the second optical component 22 includes a second metalens for focusing polarized light signals. A nanostructure unit is provided on at least one of the light input side or the light output side of the second metalens. The nanostructure unit is used to form a metasurface.

[0200] Combine Figure 7 As shown, the second metalens includes a base layer sub and a nanostructure cell for forming a metasurface. In some embodiments, a cover layer sup is provided outside the nanostructure cell.

[0201] In one embodiment, the thickness of the first super lens is greater than 0.2 mm; in one embodiment, the thickness of the first super lens is less than 0.8 mm.

[0202] In one embodiment, the thickness of the cover layer sup is 2 μm. In one embodiment, the thickness of the base layer sub is 500 μm.

[0203] In one embodiment, the second optical component 22 achieves focusing through a refractive lens.

[0204] In a specific embodiment, the second optical component 22 includes a first refractive lens 221 , a second refractive lens 222 , a third refractive lens 223 and a fourth refractive lens 224 for focusing polarized light signals.

[0205] In one embodiment, the first refractive lens 221 , the second refractive lens 222 , the third refractive lens 223 and the fourth refractive lens 224 are all spherical lenses.

[0206] In a specific embodiment, the first refractive lens 221 and the third refractive lens 223 are convex lenses, and the second refractive lens 222 and the fourth refractive lens 224 are concave lenses.

[0207] For any of the above embodiments, the second optical component 22 can focus the at least two polarized light signals output by the light modulation element 11 to different areas of the light sensor 12 to comprehensively determine the image information and other feature information of the target object OBJ.

[0208] Figure 8 The figure shows how the modulation transfer function (MTF) of the optical module 100 determined according to the present application changes with the spatial frequency (unit: cycles per mm) in different positions and conditions. Specifically, the changes in the diffraction limit-tangential direction (Diff.limit-tangential), diffraction limit-sagittal direction (Diff.limit-sagittal), 37.00 degree field angle-tangential direction (37.00(deg)-tangential), 37.00 degree field angle-sagittal direction (37.00(deg)-sagittal), 0.00 degree field angle-tangential direction (0.00(deg)-tangential), 0.00 degree field angle-sagittal direction (0.00(deg)-sagittal), -37.00 degree field angle-tangential direction (-37.00(deg)-tangential), -37.00 degree field angle-sagittal direction (-37.00(deg)-sagittal) and other situations are shown.

[0209] Figure 9 The figure shows how the relative illumination (Relative Illumination) of the optical module 100 determined according to the present application changes with the field of view (Field / deg).

[0210] Figure 10FIG1 shows how the phase distribution (in periods of 2π radians each) of the metasurface of the first optical component 21 or the metasurface of the second optical component 22 in the optical module 100 determined according to the present application changes with the position (in millimeters) of the nanostructure unit.

[0211] Figure 11 The figure shows how the phase distribution (in periods of 2piradians each) of the metasurface formed by the grating structure units of the optical modulator element 11 in the optical module 100 determined according to the present application changes with the position (unit: millimeter) of the nanostructure units.

[0212] In one embodiment, the metasurface located on the side of the light modulating element 11 close to the target object OBJ in the optical module 100 (for example, the metasurface of the first optical component 21 or the metasurface of the filter 20) is configured to be insensitive to polarization to prevent loss of imaging quality.

[0213] In one embodiment, the metasurface in the present application can also improve efficiency in large field of view angles by varying the period.

[0214] For example, based on the reference point (0°, 380 nm), the period is reduced from 380 nm to 370 nm in the 0-15° range to compensate for the Bragg condition shift.

[0215] For example, based on the reference point (20°, 360nm), the period decreases from 370nm to 370nm in the 15-30° range, maintaining the efficiency expansion with angle.

[0216] For example, based on the reference point (30°, 340nm), the period is reduced from 355nm to 320nm in the 30-40° range to cope with the nonlinear shift of the Bragg condition at large angles.

[0217] In one embodiment, the nanostructure units of the metasurface in the present application can be prepared by means of EBL (E-Beam Lithography) or UV lithography.

[0218] Figure 12 (a) shows image information of the target object OBJ obtained based on infrared imaging in one case. Figure 12 (b) shows image information including four sub-images generated by imaging the same target object OBJ by the optical module 100 provided by the present application. Figure 12In the image information in (b), the sub-image in the upper right corner corresponds to the first polarization signal, and at least one of the other three sub-images corresponds to the second polarization signal. As can be seen, the sub-image corresponding to the first polarization signal effectively eliminates reflections from the target object OBJ, while the sub-image corresponding to the second polarization signal retains more characteristic details of the target object OBJ.

[0219] Figure 13 (a) shows image information of the target object OBJ obtained based on infrared imaging in another dark environment. Figure 13 (b) shows image information including four sub-images generated by imaging the same target object OBJ by the optical module 100 provided by the present application. Figure 13 In the image information in (b), the sub-image in the upper right corner corresponds to the first polarization signal, and at least one of the other three sub-images corresponds to the second polarization signal. As can be seen, the sub-image corresponding to the first polarization signal can distinguish the boundary of the target object OBJ, while the sub-image corresponding to the second polarization signal preserves the characteristic details of the brighter areas of the target object OBJ.

[0220] In addition, although the first optical component 21 and the second optical component 22 are named "components", this does not limit the first optical component 21 and the second optical component 22 to necessarily be composed of multiple parts. The naming only indicates that the present application includes an embodiment in which the first optical component 21 and the second optical component 22 are configured to be composed of multiple parts.

[0221] Compact configuration

[0222] One embodiment of the present application provides an optical module with a compact configuration, such as Figure 14 shown.

[0223] The optical module 100 includes a light modulation element 11 .

[0224] The optical module 100 includes a light sensor 12 .

[0225] The optical module 100 includes a processor 13 .

[0226] In one embodiment, the optical module 100 further includes a first optical component 21 . The first optical component 21 is used to converge incident light from the target object OBJ and output the light to the light modulation element 11 .

[0227] A metasurface may be formed at the first optical component 21. The first optical component 21 may achieve light convergence through the metasurface.

[0228] The first optical component 21 and the light modulating element 11 can be integrated. Specifically, for example, the optical module 100 includes a module assembly, with a metasurface formed on one side of the module assembly as the first optical component 21, and another metasurface formed on the other side of the module assembly as the light modulating element 11. In this way, the optical module 100 is constructed of a planar structure, which can greatly reduce its volume and achieve a compact design.

[0229] In one embodiment, the optical module 100 further includes a second optical component 22 . The second optical component 22 is configured to focus the polarized light signal generated by the light modulation element 11 onto the light sensor 12 .

[0230] A metasurface may be formed at the second optical component 22. The second optical component 22 achieves focusing through the metasurface.

[0231] The second optical component 21 and the light modulating element 11 can be integrated. Specifically, for example, the optical module 100 includes two module components, with a metasurface formed on one module component as the light modulating element 11, and another metasurface formed on the other module component as the second optical component 22. In this way, the optical module 100 is constructed of a planar structure, which can greatly reduce its volume and achieve a compact design.

[0232] In one embodiment, the optical module 100 may include an integrated first optical component 21, a light modulating element 11, and a second optical component 22. The first optical component 21, the light modulating element 11, and the second optical component 22 may be arranged in sequence along the propagation direction of incident light from the target object in this integrated structure.

[0233] In one embodiment, the optical module 100 has an effective imaging focal length f, and the light modulating element 11 forms a diffraction angle θ after receiving a 0-degree incident light. grating . Effective imaging focal length f and diffraction angle θ grating Can satisfy: 0.2 <f*tan(θ grating )<0.4. Thus, by coordinating the design of the light modulation element 11 and the imaging focal length of the optical module 100, the center of the sub-image generated by the polarized light signal is shifted to a preset optimal range.

[0234] Preferably, f*tan(θ grating )=0.32.

[0235] In one embodiment, the size IMGH of the target surface of the optical sensor 12 is greater than 4.4 mm.

[0236] The size of the target surface may be the length of the diagonal line of the target surface of the optical sensor 12. In this way, it is possible to ensure that the optical module 100 has a sufficiently large image surface and pixel number, for example, the sub-image has a sufficient number of pixels.

[0237] In one embodiment, the first optical component 21 and the light modulation element 11 as a whole have a first focal length f1, and the second optical component 22 has a second focal length f2. The first focal length f1 and the second focal length f2 may satisfy: 20 < f1 / f2 < 40. Thus, by restricting the ratio of the first focal length f1 and the second focal length f2, the optical module 100 can image at a preset area on the target surface of the light sensor 12 after passing through the first optical component 21, the light modulator 11, and the second optical component 22 at a relatively large incident angle (for example, an incident angle of 70 degrees); ensuring that the area of the circular sub-image corresponding to the polarized light signal reaches the maximum on the premise of non-interference with each other and not exceeding the display screen of the image information.

[0238] Preferably, f1 / f2 = 26.5.

[0239] In one embodiment, the second optical component has a field of view range FOV corresponding to the target surface of the light sensor image , and the light modulation element forms a diffraction angle θ after receiving the incident light at 0 degrees grating , 1.5 < FOV image / θ grating < 3. Thus, by restricting the relationship between the field of view range FOV image and the diffraction angle θ grating , the polarized light signal is offset to a suitable position on the target surface of the light sensor 12, and the sub-image is offset to a suitable position in the display screen of the image information.

[0240] Preferably, FOV image > 2·θ grating . Preferably, FOV image = 2.14·θ grating .

[0241] In one embodiment, the metasurface has an optical effective radius R M , and the metasurface has a maximum phase difference Δφ at a single wavelength.

[0242] At a single wavelength, the phases provided at different positions in the metasurface are generally different. The metasurface configured according to this embodiment has a better phase matching effect and can more fully exert the optical performance of the metasurface.

[0243] In one embodiment, the optical module 100 further includes a filter 20 disposed between the second optical component 22 and the light sensor 12. In one embodiment, the optical module 100 may include a filter 20 disposed on the side of the light modulation element 11 close to the light sensor 12.

[0244] The second optical component 22 and the optical filter 20 can be integrated. Specifically, for example, the optical module 100 includes a module assembly, with a metasurface formed on one side of the module assembly as the second optical component 22, and the optical filter 20 formed on the other side of the module assembly. In this way, the optical module 100 is constructed of a planar structure, which can greatly reduce its volume and achieve a compact design.

[0245] In a preferred embodiment of the present application, the optical module 100 may include a first optical component 21 , a light modulation element 11 , a second optical component 22 and a filter 20 , which are integrated into one body.

[0246] In the compact optical module 100 provided in the present application, any technical details not described above may be configured with reference to other embodiments provided above.

[0247] The compactly configured optical module 100 provided in the present application greatly reduces the volume of the optical module 100 by configuring the light modulating element 11, the first optical component 21, and the second optical component 22 to be realized by a metasurface, and the three are arranged in an integrated manner; since most elements in the module are composed of a planar structure, it is convenient to achieve a barrel-free structure; the size of the prepared optical module 100 can be less than 1.2mm*1.2mm*2mm. Compared with the traditional centimeter-level size, the eye camera prepared based on the optical module 100 provided in the present application can be compressed by at least 80%.

[0248] Figure 15The figure shows how the modulation transfer function (MTF) of the compact optical module 100 determined according to the present application changes with the spatial frequency (unit: cycles per mm) in different positions and conditions. Specifically, it shows the 37.50 degree field angle - tangential direction (37.50 (deg) -tangential), 37.50 degree field angle - sagittal direction (37.50 (deg) -sagittal), 22.50 degree field angle - tangential direction (22.50 (deg) -tangential), 22.50 degree field angle - sagittal direction (22.50 (deg) -sagittal), 7.50 degree field angle - tangential direction (7.50 (deg) -tangential), 7.50 degree field angle - sagittal direction (7.50 (deg) -sagittal), 0.00 degree field angle - tangential direction (0.00 (deg) -tangential), 0.00 degree field angle - Changes in field angle - sagittal direction (0.00(deg)-sagittal), -7.50 degree field angle - tangential direction (-7.50(deg)-tangential), -7.50 degree field angle - sagittal direction (-7.50(deg)-sagittal), -22.50 degree field angle - tangential direction (-22.50(deg)-tangential), -22.50 degree field angle - sagittal direction (-22.50(deg)-sagittal), -37.50 degree field angle - tangential direction (-37.50(deg)-tangential), -37.50 degree field angle - sagittal direction (-37.50(deg)-sagittal).

[0249] It can be seen that when the wavelength of the light source is 940±20 nm, the modulation transfer function of the optical module 100 is as low as 0.15, which can meet the usage requirements of most scenarios.

[0250] Figure 16 The figure shows how the relative illumination (RelativeIllumination) of the compact optical module 100 determined according to the present application changes with the Y field angle (Y Fieldin degrees).

[0251] It can be seen that the relative illumination drops to 95% at the edge of the field of view. Taking into account the multi-layer structure, the estimated relative illumination drop is 70%, which can still meet the usage requirements of most scenarios.

[0252] Figure 17FIG2 shows how the phase distribution (in periods of 2π radians each) of the metasurface of the first optical component 21 in the compactly configured optical module 100 determined according to the present application changes with the position (in millimeters) of the nanostructure unit. FIG2 shows how the phase distribution (in periods of 2π radians each) of the metasurface of the first optical component 21 changes with the position (in millimeters) of the nanostructure unit.

[0253] Figure 18 The figure shows how the phase distribution (Phase in periods of 2piradians each) of the metasurface formed by the grating structure units of the optical modulator 11 in the compact configuration of the optical module 100 determined according to the present application changes with the position (unit: millimeter) of the nanostructure units.

[0254] Figure 19 FIG2 shows how the phase distribution (in periods of 2π radians each) of the metasurface of the second optical component 22 in the compactly configured optical module 100 determined according to the present application changes with the position (in millimeters) of the nanostructure unit. FIG2 shows how the phase distribution (in periods of 2π radians each) of the metasurface of the second optical component 22 changes with the position (in millimeters) of the nanostructure unit.

[0255] In one embodiment, Figure 20 As shown, the compact optical module 100 may include a first module assembly 1A. The first module assembly 1A may be formed as a wafer.

[0256] The first module assembly 1A includes a first optical component 21 disposed on a first side and formed as a metasurface. The first side of the first module assembly 1A may be the front of the first module assembly 1A. The first side of the first module assembly 1A may be overprinted with black glue or chrome-plated for light shielding.

[0257] The first module assembly 1A includes a light modulation element 11 disposed on a second side and formed as a metasurface. The second side of the first module assembly 1A may be the back side of the first module assembly 1A. The second side of the first module assembly 1A may be overprinted with black resin or chrome-plated for light shielding.

[0258] In one embodiment, the compact optical module 100 may include a second module assembly 1B. The second module assembly 1B may be formed as a wafer.

[0259] The second module assembly 1B can be integrated with the first module assembly 1A. For example, conventional semiconductor manufacturing processes can be used to expose and etch the metasurfaces and bonding marks of the first and second module assemblies 1A and 1B, respectively. The front aperture and back inactive area shielding can then be overetched. Anodic bonding is then performed using pre-fabricated bonding alignment marks to bond the first and second module assemblies 1A and 1B together. Finally, the wafer structure is cut according to pre-designed cutting marks, with the cut dimensions 50 μm smaller than the package size of the optical sensor 12.

[0260] The second module assembly 1B includes a second optical component 22 disposed on a second side and formed as a metasurface. The second side of the second module assembly 1B may be the back side of the second module assembly 1B. The second side of the second module assembly 1B may be overprinted with black glue or chrome-plated for light shielding.

[0261] In one embodiment, the compact optical module 100 may include a third module assembly 1C. The third module assembly 1C may be formed as a wafer.

[0262] The third module assembly 1C can be integrated with the second module assembly 1B. For example, conventional semiconductor manufacturing processes can be used to expose and etch the metasurfaces and bonding marks of the second and third module assemblies 1B and 1C, respectively. The front aperture and back inactive area shielding can then be overetched. Anodic bonding is then performed using pre-fabricated bonding alignment marks to bond the second and third module assemblies 1B and 1C together. Finally, the wafer structure is cut according to pre-designed cutting marks, with the cut dimensions being 50 μm smaller than the package size of the optical sensor 12.

[0263] The third module assembly 1C is formed with a filter. The filter is specifically a 940nm narrow-band infrared filter. Black or chrome-plated light shielding can be set on both sides of the filter along the direction of incident light.

[0264] Preferably, the first module assembly 1A, the second module assembly 1B and the third module assembly 1C are provided as one body.

[0265] In one embodiment, the three integrated module components are attached to the optical sensor 12 through an AA (Active Alignment) process to complete the packaging of the optical module 100 .

[0266] In one embodiment, Figure 21 As shown, the compact optical module 100 may further include a light shielding layer 1D. The light shielding layer 1D is disposed on the outer wall of the three integrated module components. The light shielding layer 1D is used to block ambient light while avoiding increasing the overall volume of the optical module 100. The light shielding layer 1D may have a thickness of 50 μm.

[0267] The light shielding layer 1D may be ink and is formed by inkjet printing.

[0268] The light shielding layer 1D may be made of black resin and formed by integral injection molding.

[0269] Eye tracking methods

[0270] An embodiment of the present application provides an eye tracking method, such as Figure 22 shown.

[0271] The eye tracking method can be implemented in the above-mentioned optical module or eye camera.

[0272] The eye tracking method provided in this application includes at least one of the following steps.

[0273] Step S11: obtaining eye image information using an optical module.

[0274] Step S12: obtaining eye image information from the eye camera.

[0275] Step S21 : determining the pupil position and / or reflection position according to the first sub-image, and determining the current sight direction of the eyeball.

[0276] Step S22: determining the pupil position and / or the reflection point position according to the first sub-image and the second sub-image, and determining the current sight direction of the eyeball.

[0277] The image information includes a first sub-image corresponding to the first polarized light signal and a second sub-image corresponding to the second polarized light signal.

[0278] In one embodiment, the reflection position may be a position of a reflection light spot. Preferably, the reflection light spot may be a Purkinje spot.

[0279] Preferably, PCCR can be performed to determine the current sight direction of the eyeball based on the pupil position and the reflection position.

[0280] In step S21, the pupil position and / or reflection position can be directly determined based on the sub-image information corresponding to the first polarized light signal. In step S22, the sub-image information corresponding to the first polarized light signal may have lost some characteristic information, making it difficult to distinguish the pupil position and reflection position. Therefore, the sub-image information corresponding to the second polarized light signal can be combined with the characteristic information of the eyeball to compensate for the pupil position and reflection position.

[0281] In one embodiment, the eye tracking method performs steps S11 and S21. In one embodiment, the eye tracking method performs steps S12 and S21. In one embodiment, the eye tracking method performs steps S11 and S22. In one embodiment, the eye tracking method performs steps S12 and S22.

[0282] In one embodiment, the image information includes a first sub-image corresponding to the first polarized light signal, a second sub-image corresponding to the second polarized light signal, a third sub-image corresponding to the third polarized light signal, and a fourth sub-image corresponding to the fourth polarized light signal. In a specific embodiment, the image information is as follows: Figure 12 (b) or Figure 13 As shown in (b).

[0283] Step S22 may further include: determining the pupil position and / or reflection point position according to the first sub-image, the second sub-image, the third sub-image and the fourth sub-image, and determining the current sight direction of the eyeball.

[0284] In one embodiment, the image information includes a first sub-image corresponding to a first polarized light signal, a second sub-image corresponding to a second polarized light signal, and n-2 sub-images corresponding to other n-2 polarized lights.

[0285] Step S22 may further include: determining the pupil position and / or the reflection point position according to the n sub-images, and determining the current sight direction of the eyeball.

[0286] In one embodiment, the eye tracking method provided in the present application may include at least one of the following steps.

[0287] Step S221 , obtaining a linear superposition image of the first sub-image and the second sub-image, determining the pupil position and / or the reflection point position, and determining the current sight direction of the eyeball.

[0288] In some embodiments, a linear superposition image of the first sub-image, the second sub-image, the third sub-image, and the fourth sub-image may also be obtained.

[0289] In some embodiments, a linear superposition image of all n sub-images may also be obtained.

[0290] Compared with the sub-image corresponding to the polarized light signal, the linear superposition image can more clearly show the boundary of the target object, which helps to determine the pupil position and reflection position.

[0291] Figure 23 (a) shows the corresponding Figure 12 The linear superposition image in (b) is Figure 23 (b) shows the corresponding Figure 13 Linear overlay image in (b).

[0292] Step S222 , determining a polarization image based on the first sub-image and the second sub-image, determining the pupil position and / or the reflection point position, and determining the current sight direction of the eyeball.

[0293] Compared to the sub-image corresponding to the polarized light signal, the degree of polarization (DoLP) image has a unified display of the color of the target object (for example, skin and pupil color), while emphasizing the differences between different materials. This is conducive to distinguishing the boundaries of the target object, and is particularly helpful for constructing training sets for eye feature recognition-related algorithms.

[0294] The polarization image may appear as a color jump at the boundary of the target object, for example, a grayscale jump.

[0295] Since the skin and pupil materials of different individuals and even different races are unified, there is no need to classify different objects when constructing the training set. The eye feature recognition-related algorithms determined based on this have better generalization recognition capabilities and recognition accuracy, and the detection accuracy of special situations such as microsaccade detection is also higher.

[0296] In some embodiments, a polarization degree image may also be determined based on the first sub-image, the second sub-image, the third sub-image, and the fourth sub-image.

[0297] In some embodiments, a polarization degree image may also be determined based on all n sub-images.

[0298] In a specific embodiment, the polarization value of each corresponding pixel in several sub-images may be calculated based on the intensity of the pixel, and a polarization image may be generated based on the polarization values ​​of all pixels (eg, by mapping the polarization values ​​to grayscale).

[0299] Figure 24 (a) shows the corresponding Figure 12 Polarization degree image in (b), Figure 25 (a) shows the corresponding Figure 13 Polarization degree image in (b).

[0300] Step S223 , determining a polarization angle image based on the first sub-image and the second sub-image, determining the pupil position and / or the reflection point position, and determining the current sight direction of the eyeball.

[0301] Compared to the sub-image corresponding to the polarized light signal, the angle of polarization (AoP) image has a unified display of the color of the target object (for example, skin and pupil color), while emphasizing the differences between different materials. This is conducive to distinguishing the boundaries of the target object and is particularly helpful for constructing training sets for eye feature recognition algorithms.

[0302] Polarization angle images can appear as color rotation at the boundaries of the target object, for example, color rotation.

[0303] Since the skin and pupil materials of different individuals and even different races are unified, there is no need to classify different objects when constructing the training set. The eye feature recognition-related algorithms determined based on this have better generalization recognition capabilities and recognition accuracy, and the detection accuracy of special situations such as microsaccade detection is also higher.

[0304] In some embodiments, a polarization angle image may also be determined based on the first sub-image, the second sub-image, the third sub-image, and the fourth sub-image.

[0305] In some embodiments, the polarization angle image may also be determined based on all n sub-images.

[0306] In a specific embodiment, the polarization angle of each corresponding pixel in several sub-images can be calculated based on the intensity of the pixel, and a polarization angle image can be generated based on the polarization angles of all pixels (for example, the polarization angles are mapped into pseudo colors).

[0307] Figure 24 (b) shows the corresponding Figure 12 The polarization angle image in (b) (converted to grayscale), Figure 25 (b) shows the corresponding Figure 13 Polarization angle image in (b) (converted to grayscale).

[0308] At least one of the optical module, eye camera and eye tracking method provided in this application can generate the following when implemented: Figure 26 The image information shown in (a).

[0309] Preferably, according to the plurality of sub-images in the image information, it is possible to determine Figure 26 The polarization image shown in (b) shows a color jump at the pupil boundary, which helps determine the pupil position and the current line of sight.

[0310] Preferably, according to the plurality of sub-images in the image information, it is possible to determine Figure 26 The polarization angle image shown in (c) in the figure. In the polarization angle image, the color at the pupil boundary rotates around the pupil, which helps determine the pupil position and the current line of sight.

[0311] In summary, the optical module provided by the present application, by configuring the light modulation element, generates a first polarized light that is orthogonal to the polarization state of the incident light and a second polarized light that is non-orthogonal to the polarization state of the incident light, thereby achieving dual optimization of reflection suppression and detail enhancement in the target recognition scenario. On the one hand, the first polarized light can effectively suppress the mirror reflection of the target surface, reduce the influence of interfering light, thereby enhancing the contrast between the target object and the background, and improving the boundary resolution ability. On the other hand, the non-orthogonal polarized light retains the high-frequency texture and microstructure information in part of the reflected light, making up for the detail loss problem caused by excessive filtering in traditional polarization imaging, making the imaging results more suitable for high-precision recognition (such as eye micro-movement tracking) or complex environments (such as multi-light source interference). In this way, while improving the discrimination of the target object, the richness of the details of the imaging is taken into account, and the applicability of polarization imaging in low signal-to-noise ratio and high dynamic range scenarios is expanded.

[0312] It should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0313] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of this application. They are not intended to limit the scope of protection of this application. Any equivalent implementation methods or changes that do not deviate from the technical spirit of this application should be included in the scope of protection of this application.

Claims

1. An optical module, characterized in that: include: The light modulation element is configured to receive incident light from a target object and generate a first polarized light signal and a second polarized light signal, wherein the first polarized light signal is orthogonal to the polarization state of the incident light, and an inner product of the second polarized light signal and a Jones vector of the incident light is greater than 0 or less than 0. The optical sensor is configured to receive a first polarized light signal and a second polarized light signal to generate data information. The processor is coupled to the light sensor and is configured to determine image information of the target object according to the data information.

2. The optical module according to claim 1, wherein: The light modulation element includes a grating structure unit arranged at at least one of the light incident side or the light exit side of the light modulation element, wherein the grating structure unit is used to modulate the polarization state of light and the grating structure unit is used to form a metasurface.

3. The optical module according to claim 1, wherein: The optical sensor is used to generate first data information according to the first polarized light signal, and the processor is used to generate a first sub-image according to the first data information. The optical sensor is used to generate second data information according to the second polarized light signal, and the processor is used to generate a second sub-image according to the second data information. The processor determines at least one of contour information, shape information, position information, and posture information of the target object based on the first sub-image and the second sub-image.

4. The optical module according to claim 1, wherein: The light modulation element is further configured to receive incident light from a target object and generate a third polarized light signal and a fourth polarized light signal. The optical sensor is used to receive the first polarized light signal, the second polarized light signal, the third polarized light signal and the fourth polarized light signal to generate data information. The first polarized light signal has a linear polarization state at a first angle, the second polarized light signal has a linear polarization state at a second angle, the third polarized light signal has a linear polarization state at a third angle, and the fourth polarized light signal has a linear polarization state at a fourth angle. The difference between adjacent angles among the first angle, the second angle, the third angle and the fourth angle is 45 degrees.

5. The optical module according to claim 1, wherein: The light modulator is used to receive incident light from the target object and generate n groups of polarized light signals in n areas of the light sensor. The optical sensor is used to receive n groups of polarized light signals to generate data information. The processor is used to determine image information including n sub-images according to the data information, where the n sub-images correspond to n groups of polarized light signals at n regions.

6. The optical module according to claim 1, wherein: Along the propagation direction of the incident light of the target object, the optical module includes: a first optical component, configured to converge incident light from a target object and output the light to a light modulation element; light modulation element, The second optical component is used to focus the polarized light signal generated by the light modulation element to the light sensor, Light sensor, processor, The first optical component is configured according to at least one of the following: The first optical component includes a first metalens for converging incident light, and a nanostructure unit is provided on at least one of the light entrance side or the light exit side of the first metalens, wherein the nanostructure unit is used to form a metasurface. The first optical component includes at least one refractive lens for converging incident light, The second optical component is configured according to at least one of the following: The second optical component includes a second metalens for focusing polarized light signals, and a nanostructure unit is provided on at least one of the light input side or the light output side of the second metalens, wherein the nanostructure unit is used to form a metasurface. The second optical assembly includes a first refractive lens, a second refractive lens, a third refractive lens and a fourth refractive lens for focusing polarized light signals. The first refractive lens and the third refractive lens are convex lenses, and the second refractive lens and the fourth refractive lens are concave lenses.

7. The optical module according to claim 1, 5 or 6, wherein: Based on at least one of the following configurations: The optical module has an effective imaging focal length f, and the light modulator forms a diffraction angle θ after receiving 0-degree incident light. grating , f*tan(θ grating )>0.5, The optical sensor target surface size IMGH is greater than 3.4mm, The optical module also includes a first optical component and a second optical component. The first optical component is used to converge the incident light from the target object and output it to the light modulation element. The second optical component is used to focus the polarized light signal generated by the light modulation element to the light sensor. The first optical component and the light modulation element have a first focal length f1 as a whole, and the second optical component has a second focal length f2. <f1 / f2<90, The optical module also includes a second optical component, which is used to focus the polarized light signal generated by the light modulator to the light sensor. The second optical component has a field of view angle range FOV corresponding to the target surface of the light sensor. image , the light modulator forms a diffraction angle θ after receiving the 0 degree incident light grating , FOV image >3·θ grating .

8. The optical module according to claim 1, 5 or 6, wherein: The optical module includes a first optical component, a light modulating element, and a second optical component that are integrated into one body. The first optical component is used to converge the incident light from the target object and output it to the light modulating element. The second optical component is used to focus the polarized light signal generated by the light modulating element to the light sensor. The optical module is configured according to at least one of the following: The optical module has an effective imaging focal length f, and the light modulator forms a diffraction angle θ after receiving 0-degree incident light. grating , 0.2 <f*tan(θ grating )<0.4, The optical sensor target surface size IMGH is greater than 4.4mm, The first optical component and the light modulation element have a first focal length f1 as a whole, and the second optical component has a second focal length f2. <f1 / f2<40, The second optical component corresponds to the target surface of the optical sensor and has a field of view angle range FOV image , the light modulator forms a diffraction angle θ after receiving the 0 degree incident light grating , 1.5 <FOV image / θ grating <3.

9. The optical module according to claim 1 or 6, wherein: Based on at least one of the following configurations: The optical module also includes an aperture and a second optical component. The aperture is arranged on the light-emitting side of the light modulator. The second optical component is used to focus the polarized light signal passing through the aperture to the light sensor. There is a distance d of 0.04 mm between the light modulator and the aperture. <d<0.8mm, The optical module also includes a first optical component, which is used to converge the incident light from the target object and output it to the light modulation element. The first optical component includes at least two refractive lenses, and there is a refractive index difference N between any two refractive lenses in the first optical component. i -N i+1 , 0.01 <N i -N i+1 <0.2, the refractive lens in the first optical component has an Abbe number V, 18 <V<57, The optical module also includes a second optical component, which is used to focus the polarized light signal generated by the light modulation element to the light sensor. The second optical component includes at least two refractive lenses. There is a refractive index difference N between any two refractive lenses in the second optical component. i -N i+1 , 0.01 <N i -N i+1 <0.2, the refractive lens in the second optical component has an Abbe number V, 18 <V<57。 10. The optical module according to claim 1, wherein: The optical module includes a first light modulator and a second light modulator. A grating structure unit is provided at at least one of the light input side or the light output side of the first light modulator, and the grating structure unit is used to modulate the polarization state of light. A nanostructure unit is provided at at least one of the light input side or the light output side of the second light modulator, and the nanostructure unit is used to form a metasurface.

11. The optical module according to claim 2, 6 or 10, wherein: Based on at least one of the following configurations: The metasurface has an optical effective radius R M , the metasurface has a maximum phase difference Δφ at a single wavelength, 30<|Δφ / R M |<50, The metasurface has an operating wavelength λ, and the metasurface has a phase related to the operating wavelength The metasurface has a focal length f M , the metasurface has a subwavelength structure with a distance r from the center of the metasurface, and the subwavelength structure has a phase N is the phase order, The metasurface has an operating wavelength λ, and the metasurface has a phase related to the operating wavelength The metasurface has a focal length f M , the metasurface has a subwavelength structure with a distance r from the center of the metasurface, and the subwavelength structure has a phase The metasurface has an operating wavelength λ, and the metasurface has a phase related to the operating wavelength The metasurface has a focal length f M , the metasurface has a subwavelength structure with a distance r from the center of the metasurface, and the subwavelength structure has a phase 12. The optical module according to claim 2, 6 or 10, wherein: The optical module includes a first optical component, a light modulating element, and a second optical component that are integrated into one body. The first optical component is used to converge the incident light from the target object and output it to the light modulating element. The second optical component is used to focus the polarized light signal generated by the light modulating element to the light sensor. The metasurface has an optical effective radius R M , the metasurface has a maximum phase difference Δφ at a single wavelength, 50<|Δφ / R M |<750.

13. An eye camera, characterized in that: comprising the optical module according to any one of claims 1 to 12, The eye camera is arranged on the optical path of the light emitted from the eyeball to receive the incident light from the eyeball. The optical module in the eye camera is configured to use at least one of the eyeball, the pupil, or the reflection point formed by the light source at the eyeball as the target object.

14. The eye camera according to claim 13, wherein: The optical module has an imaging field of view FOV, and the distance between the eye camera and the eyeball is h.

15. The eye camera according to claim 13, wherein: The eye camera is used to determine the current sight direction of the eyeball based on the pupil position and the reflection point position. The reflex point is the Purchin spot.

16. An eye tracking method, characterized in that: include: The optical module according to any one of claims 1 to 12, or the eye camera according to any one of claims 13 to 15, obtaining image information of the eye, the image information comprising a first sub-image corresponding to the first polarized light signal and a second sub-image corresponding to the second polarized light signal; and one of the following: Determine the pupil position and / or reflection position based on the first sub-image, and determine the current sight direction of the eyeball. The pupil position and / or the reflection point position are determined according to the first sub-image and the second sub-image, and the current sight direction of the eyeball is determined.

17. The eye tracking method according to claim 16, wherein: Include at least one of the following: Obtain a linear superposition image of the first sub-image and the second sub-image, determine the pupil position and / or reflection point position, and determine the current sight direction of the eyeball. Determine the polarization image based on the first sub-image and the second sub-image, determine the pupil position and / or the reflection point position, and determine the current sight direction of the eyeball. A polarization angle image is determined based on the first sub-image and the second sub-image, the pupil position and / or the reflection point position are determined, and the current sight direction of the eyeball is determined.

Images