Optical equipment

Abstract

The invention relates to the field of display equipment, and discloses optical equipment. In the optical equipment provided by the invention, the infrared light source and the eye movement camera module are arranged on one side of the optical assembly, and the corresponding polarization assemblies are respectively added on the light emitting side (such as the light emitting surface of the infrared light source) of the infrared light source and the light incident side (such as the light incident surface of the eye movement camera module) of the eye movement camera module. The light emitted by the polarization assembly on the infrared light source and the light which can penetrate through the polarization assembly on the eye movement camera module are both circular polarization light, and the rotation directions of the light are the same (for example, the light is in a left-hand circular polarization state or a right-hand circular polarization state). Thus, the situation that part of reflected light rays needing to be collected cannot be collected can be avoided, stray light can be effectively blocked, and the eye movement tracking recognition precision can be improved.

Description

Technical Field

[0001] This application relates to the field of display devices, and more particularly to an optical device. Background Technology

[0002] Currently, eye-tracking technology has been widely used in head-mounted display devices such as augmented reality (AR), virtual reality (VR), and mixed reality (MR). For example, in... Figure 1 When the MR device 001 shown is used for display, it can obtain the position of the user's gaze point based on eye-tracking technology, thereby achieving high-quality rendering of the image corresponding to the gaze point position and improving the user's visual experience.

[0003] An eye-tracking system typically consists of an infrared light source, an eye-tracking camera module, and optical components. Eye tracking is achieved by the infrared light source emitting light towards the eye area. The emitted infrared light is reflected by the eye, and this reflected light is then transmitted through the optical components and captured by the eye-tracking camera module. The eye-tracking camera module analyzes and extracts the user's gaze information based on the captured reflected light.

[0004] However, when the human eye focuses on the edge of the field of vision, the incident angle of the infrared light incident on the eyeball is large, which makes the reflection angle of the light reflected from the eyeball large. There may be cases where some reflected light cannot be collected by the eye-tracking camera module, resulting in low accuracy of the extracted user gaze information, that is, low accuracy of eye tracking recognition. Summary of the Invention

[0005] This application provides an optical device that can avoid situations where some of the reflected light that needs to be collected cannot be collected by the eye-tracking camera module, and can effectively block stray light, thereby improving the accuracy of eye-tracking recognition.

[0006] This application provides an optical device including a light source, an optical component, an eye-tracking camera module, a first polarization component, and a second polarization component. The first polarization component is disposed on the light-emitting side of the light source and is used to convert a first light emitted by the light source into a second light and to incident the second light onto the optical component, wherein the second light is circularly polarized light with a first rotation direction. The second polarization component is disposed on the light-incident side of the camera module and is used to transmit the circularly polarized light with the first rotation direction transmitted by the optical component and to block the circularly polarized light with the second rotation direction transmitted by the optical component, wherein the second rotation direction is opposite to the first rotation direction.

[0007] In the optical device provided in this application, an infrared light source and an eye-tracking camera module are disposed on one side of the optical assembly. Corresponding polarization components are added to the light-emitting side (e.g., the light-emitting surface of the infrared light source) and the light-incident side (e.g., the light-incident surface of the eye-tracking camera module), respectively. This ensures that the light emitted from the polarization component on the infrared light source and the light transmitted through the polarization component on the eye-tracking camera module are both circularly polarized, and that the directions of rotation of the light are the same (e.g., both are left-handed circularly polarized, or both are right-handed circularly polarized). It can be understood that transmitting the optics emitted by the infrared light source through the optical assembly limits the position of the infrared light source and the eye-tracking camera module to one side. This reduces the range of the incident angle of the infrared light emitted from the infrared light source to the eye region, thus reducing the range of the reflection angle of the light reflected from the eye region and preventing the reflected light from being undetectable by the eye-tracking camera module.

[0008] Furthermore, when the light emitted from the polarization component of the infrared light source is circularly polarized, the rotation directions of the circular polarization states of the two stray lights generated during light transmission are opposite to those of the circularly polarized light emitted from the polarization component of the infrared light source (see below). Figure 4 and Figure 5 (Explanation of the light transmission process) Therefore, by setting the direction of the circular polarization state of the light transmitted by the polarization component on the eye-tracking camera module to be the same as the direction of the circular polarization state of the light emitted by the polarization component on the infrared light source, the direction of the circular polarization state of the light transmitted by the polarization component on the eye-tracking camera module can be opposite to the direction of the circular polarization state of the two stray lights, thus effectively blocking the two stray lights.

[0009] In one possible implementation of this application embodiment, the first polarization component is disposed on the light-emitting surface of the light source, and the second polarization component is disposed on the light-incident surface of the eye-tracking camera module.

[0010] It is understood that in some embodiments, the first polarization component can be disposed on the light-emitting surface of the infrared light source, for example, attached to the light-emitting surface of the infrared light source, or disposed on the light-emitting side of the infrared light source at a predetermined distance from the light-emitting surface; this application does not impose any limitation. The second polarization component can be disposed on the light-incident surface of the eye-tracking camera module, for example, attached to the light-incident surface of the eye-tracking camera module, or disposed on the light-incident side of the eye-tracking camera module at a predetermined distance from the light-incident surface; this application does not impose any limitation.

[0011] In one possible implementation of the embodiments of this application, the first rotation direction is left-handed and the second rotation direction is right-handed; or, the first rotation direction is right-handed and the second rotation direction is left-handed.

[0012] In one possible implementation of this application embodiment, the first polarization component includes a first QWP and a first POL, with the light-emitting surface of the light source and the first QWP located on opposite sides of the first POL; the second polarization component includes a second POL and a second QWP, with the light-incident surface of the camera module and the second QWP located on opposite sides of the second POL.

[0013] In one possible implementation of this application embodiment, the first POL is used to convert the first light ray into a third light ray and to transmit the third light ray to the first QWP, and the first QWP is used to convert the third light ray into a second light ray, wherein the third light ray is linearly polarized light.

[0014] In some embodiments, the first POL is used to convert the light emitted by the infrared light source into linearly polarized light and transmit the linearly polarized light to the first QWP, which is used to convert the linearly polarized light into left-handed or right-handed circularly polarized light.

[0015] In some embodiments, the linearly polarized light transmitted by the first POL can be converted into left-handed or right-handed circularly polarized light by matching the angle of the transmission axis of the first POL and the angle of the slow axis of the first QWP. For example, if the difference between the angle of the transmission axis of the first POL and the angle of the slow axis of the first QWP is -45 degrees, the linearly polarized light transmitted by the first POL can be converted into left-handed circularly polarized light. If the difference between the angle of the transmission axis of the first POL and the angle of the slow axis of the first QWP is 45 degrees, the linearly polarized light transmitted by the first POL can be converted into right-handed circularly polarized light.

[0016] In one possible implementation of this application embodiment, the second QWP is used to convert circularly polarized light of the first rotation direction transmitted by the optical component into linearly polarized light of the first polarization direction, and to convert circularly polarized light of the second rotation direction transmitted by the optical component into linearly polarized light of the second polarization direction; the second POL is used to transmit linearly polarized light of the first polarization direction and to block linearly polarized light of the second polarization direction.

[0017] In some embodiments, the second POL and the second QWP can be matched to block left-handed or right-handed circularly polarized light from incident on the eye-tracking camera module. For example, the second QWP can be used to convert first-direction circularly polarized light transmitted from the optical component into first-type linearly polarized light, and to convert second-direction circularly polarized light transmitted from the optical component into second-type linearly polarized light; the second POL can be used to transmit the first-type linearly polarized light to the eye-tracking camera module and to block the second-type linearly polarized light. It is understood that the first-direction circularly polarized light has the same direction of rotation as the circularly polarized light modulated and transmitted by the first polarization component.

[0018] In one possible implementation of this application embodiment, the optical device further includes a screen; along a first direction, a light source and an eye-tracking camera module are disposed between the screen and the optical components; and the light emission direction of the screen is toward the optical components.

[0019] It is understandable that the first direction can be the direction in which the screen points to the optical components. When the light source and the eye-tracking camera module are placed between the screen and the optical components, the range of the incident angle of the infrared light emitted by the infrared light source to the eye area can be effectively reduced, so that the range of the reflection angle of the light reflected through the eye area can be reduced, avoiding the situation where the reflected light cannot be collected by the eye-tracking camera module.

[0020] In one possible implementation of this application embodiment, the optical component includes a semi-reflective and semi-transparent film layer, a third QWP, and a third polarization component disposed along a first direction; the third polarization component includes an AR, a third POL, and an RP disposed sequentially along the first direction.

[0021] In one possible implementation of this application embodiment, the light source is a near-infrared light source; the semi-reflective and semi-transparent film layer has a transmittance of 49%-51% for visible light and a transmittance of greater than or equal to 99% for near-infrared light emitted by the light source.

[0022] In this embodiment of the application, by increasing the transmittance of near-infrared light, the generation of stray light can be further effectively reduced.

[0023] In one possible implementation of this application embodiment, the light source is a near-infrared light source; the reflectivity of AR to visible light is less than 0.60%, and the reflectivity of the semi-reflective and semi-transparent film layer to the near-infrared light emitted by the light source is less than 0.25%.

[0024] In this embodiment, the reflectivity of the AR film to visible light is set to be less than 0.60%, and the reflectivity of the AR film to light emitted from an infrared light source (e.g., 850nm) is set to be less than 0.25%. This ensures light transmittance, that is, ensures the intensity of light incident on the eyeball and the intensity of light reflected from the eyeball incident on the eye-tracking camera module, thereby improving the accuracy of eye tracking. Attached Figure Description

[0025] Figure 1 A schematic diagram of an MR device is shown according to some embodiments of this application;

[0026] Figure 2A According to some embodiments of this application, a schematic diagram of the structure of an eye-tracking system 100 for an MR device is shown;

[0027] Figure 2B According to some embodiments of this application, a schematic diagram of the structure of an eye-tracking system 100 for an MR device is shown;

[0028] Figure 3 According to some embodiments of this application, a schematic diagram of the structure of an eye-tracking system 100 for an MR device is shown;

[0029] Figure 4 According to some embodiments of this application, a schematic diagram of the structure of an eye-tracking system 100 is shown;

[0030] Figure 5 According to some embodiments of this application, a schematic diagram of the structure of an eye-tracking system 100 is shown;

[0031] Figure 6A According to some embodiments of this application, a schematic diagram of the structure of a first polarization component 105 is shown;

[0032] Figure 6B According to some embodiments of this application, a schematic diagram of the structure of a second polarization component 106 is shown;

[0033] Figure 7A According to some embodiments of this application, a structural schematic diagram and an optical path transmission schematic diagram of an eye-tracking system 100 are shown;

[0034] Figure 7B According to some embodiments of this application, a structural schematic diagram and an optical path transmission schematic diagram of an eye-tracking system 100 are shown;

[0035] Figure 7C According to some embodiments of this application, a structural schematic diagram and an optical path transmission schematic diagram of an eye-tracking system 100 are shown;

[0036] Figure 7D According to some embodiments of this application, a structural schematic diagram and an optical path transmission schematic diagram of an eye-tracking system 100 are shown;

[0037] Figure 8A According to some embodiments of this application, a reflectance spectrum of a 50 / 50 semi-reflective and semi-transparent film layer is shown;

[0038] Figure 8B According to some embodiments of this application, a reflectance spectrum of an AR film is shown;

[0039] Figure 9 According to some embodiments of this application, a schematic diagram of the optical path transmission for imaging is shown. Detailed Implementation

[0040] This application provides an optical device.

[0041] For ease of understanding, the technical terms used in this application will be explained and described below.

[0042] Circularly polarized light has a light vector that rotates around the direction of light propagation, and the trajectory of the end of the light vector is a circle perpendicular to the direction of the light ray. Based on the direction of rotation of the light vector, circularly polarized light can be divided into left-handed and right-handed circularly polarized light. When the phase difference of the light rays is φ = (2m + 1 / 2)π, the light type is left-handed circularly polarized light (L); when the phase difference of the light rays is φ = (2m - 1 / 2)π, the light type is right-handed circularly polarized light (R).

[0043] Linearly polarized light, also known as plane-polarized light, refers to light rays whose light vector vibrates in only one fixed direction. As light propagates, its electric or magnetic field vectors remain within the same plane, and the direction of vibration remains unchanged. Linearly polarized light includes P-type linearly polarized light and S-type linearly polarized light. The vibration direction of P-type polarized light is parallel to the plane of incidence, while the vibration direction of S-type polarized light is perpendicular to the plane of incidence.

[0044] A quarter-wave plate (QWP) is a birefringent single-crystal waveplate of a certain thickness. By adjusting the angle of the fast axis or slow axis of the quarter-wave plate, linearly polarized light (e.g., P-type or S-type linearly polarized light mentioned in the embodiments of this application) can be converted into circularly polarized light (e.g., left-handed circularly polarized light L or right-handed circularly polarized light R mentioned in the embodiments of this application), or circularly polarized light can be converted into linearly polarized light.

[0045] An absorption polarizer (POL) is an optical element that can selectively absorb or transmit light with a specific polarization direction.

[0046] Antireflection coating (AR) is a thin film that improves the light transmittance of a material by controlling the incident angle and wavelength of light through the design of a suitable multilayer antireflection coating.

[0047] A reflective polarizer (RP) is a film similar to a wire grid polarizer (WGP). Reflective polarizers include a first type and a second type. The first type of reflective polarizer is used for total transmission of P-type polarized light and total reflection of S-type polarized light; the second type of reflective polarizer is used for total transmission of S-type polarized light and total reflection of P-type polarized light.

[0048] A 50 / 50 semi-reflective and semi-transparent beam splitter, also known as a (50 / 50) semi-reflective and semi-transparent film layer, can be used to precisely control the ratio of light reflection and transmission. After light passes through a 50 / 50 semi-reflective and semi-transparent beam splitter, the reflected light and transmitted light each account for 50%.

[0049] Transmitting axis / Absorption axis: A transmitting axis allows light to pass through only in a specific direction. When light shines on a polarizer, it only allows light in that specific direction to pass through. An absorption axis absorbs light in only a specific direction.

[0050] Slow axis / fast axis: The direction of the light vector that propagates slowly in the waveplate is the slow axis, and the direction of the light vector that propagates quickly in the waveplate is the fast axis.

[0051] The technical solutions in the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings.

[0052] It should be noted that this application does not limit the specific form of the optical device. The optical device can be any optical device that needs to realize eye tracking function, such as augmented reality (AR), virtual reality (VR), or mixed reality (MR).

[0053] Figure 2A A schematic diagram of the structure of an eye-tracking system 100 for an MR device is shown, as follows: Figure 2AAs shown, the eye-tracking system 100 of the MR device includes an infrared light source 101, an eye-tracking camera module 102, and an optical component 103. The infrared light source 101 is placed on the outer region of the optical component 103, and the eye-tracking camera module 102 is placed between the optical component 103 and the screen of the MR device. The infrared light source 101 can be an LED infrared light source, a laser infrared light source, or other forms of infrared light source, which are not limited here. The optical component 103 includes a 50 / 50 semi-reflective and semi-transparent film layer, a QWP, an RP, and a POL. The RP and POL form a composite lens. The optical component 103 can be the imaging component of the MR device; that is, the optical component 103 can be used for both imaging in the MR device and for light transmission in eye tracking. The wavelength range of the light used for imaging in the MR device (i.e., the wavelength of the light emitted by the screen of the MR device) is the visible light range, between 380nm and 780nm. The wavelength range of the light used for eye tracking is the near-infrared light range, between 780nm and 2526nm. The eye-tracking camera module 102 can capture light in the near-infrared wavelength range, therefore it will not capture imaging light and will not be interfered with by imaging light. Thus, the eye-tracking system 100 can reuse the imaging components of the MR device for light transmission.

[0054] The optical transmission path of eye tracking is as follows Figure 2A As shown, infrared light N1 emitted by infrared light source 101 illuminates the user's eye region 104 and undergoes optical reflection in the eye region 104 to obtain reflected light N2. The reflected light N2 passes through the composite lens of RP and POL and is converted into P-type linearly polarized light. The P-type linearly polarized light is converted into left-handed circularly polarized light L by QWP. 50% of the left-handed circularly polarized light L1 passes through the 50 / 50 semi-reflective and semi-transparent film layer and is finally collected by eye-tracking camera module 102. Eye-tracking camera module 102 analyzes and extracts user gaze information based on the collected left-handed circularly polarized light L1.

[0055] However, since the infrared light source 101 is placed in the outer region of the optical component 103, there may be some cases where the incident angle of the infrared light emitted by the infrared light source 101 to the eye region 104 is large, resulting in a large reflection angle of the light reflected by the eye region 104. This may cause some of the reflected light to be unable to be collected by the eye-tracking camera module 102, resulting in low accuracy of the extracted user gaze information, that is, low accuracy of eye tracking recognition.

[0056] Figure 2B Taking the example that reflected light cannot be captured by the eye-tracking camera module 102, a structural example diagram of an eye-tracking system 100 for an MR device is shown. Figure 2BAs shown in the optical path transmission path, when the human eye is focused on the edge of the field of vision, the incident angle a1 of the infrared light N1 emitted by the infrared light source 101 to the eye region 104 is large, which makes the reflection angle a2 of the light reflected by the eye region 104 large. As a result, the left-handed circularly polarized light L transmitted from the QWP can no longer be incident on the 50 / 50 semi-reflective and semi-transparent film layer. That is, the reflected light passing through the eye region 102 at this time cannot be collected by the eye-tracking camera module 102, which affects the accuracy of eye tracking and recognition.

[0057] To address the aforementioned issues, some embodiments provide an eye-tracking system 100 for MR devices with the following structure: Figure 3 As shown, the infrared light source 101 is placed between the optical component 103 and the screen of the MR device. In this way, the range of the incident angle a1 of the infrared light emitted by the infrared light source 101 to the eye region 104 is reduced, so that the range of the reflection angle a2 of the light N2 reflected by the eye region 104 can be reduced, thus avoiding the situation where the reflected light cannot be captured by the eye-tracking camera module 102.

[0058] However, in the above-mentioned scheme of placing the infrared light source 101 between the optical component 103 and the screen of the MR device, stray light with different paths will be generated during the transmission of the eye-tracking light through the optical component 103 of the MR device, and the stray light may be collected by the eye-tracking camera module 102, which seriously affects the recognition accuracy of eye tracking.

[0059] The following is combined Figure 3 The illustrated structural example diagram of the eye-tracking system 100 of the MR device explains the situation where stray light occurs during the optical path transmission of infrared light in the optical components. For example... Figure 3 As shown, infrared light N1 emitted by infrared light source 101 passes through a 50 / 50 semi-reflective and semi-transparent film layer and is converted into infrared light N2. Infrared light N2 is converted into S-type linearly polarized light S1 by QWP. S-type linearly polarized light S1 passes through a composite lens composed of RP and POL and is converted into P-type linearly polarized light P1. P-type linearly polarized light P1 emitted to the eye region is reflected by eye region 104 to obtain P-type linearly polarized light P2. P-type linearly polarized light P2 passes through a composite lens composed of RP and POL and is converted into P-type linearly polarized light P3. P-type linearly polarized light P3 passes through QWP and is converted into left-handed circularly polarized light L1. Left-handed circularly polarized light L1 passes through a 50 / 50 semi-reflective and semi-transparent film layer and is converted into left-handed circularly polarized light L2. Finally, left-handed circularly polarized light L2 is captured by eye-tracking camera module 102.

[0060] However, due to the 50 / 50 semi-reflective and semi-transparent film layer's characteristic of reflecting and transmitting light at equal ratios, 50% of the infrared light N1 emitted by the infrared light source will not pass through the 50 / 50 semi-reflective and semi-transparent film layer. This results in the non-transparent light undergoing an odd number of reflections before entering the eye-tracking camera module 102. For example, as... Figure 3 As shown in the dashed box ①, light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer is reflected by the 50 / 50 semi-reflective and semi-transparent film layer, resulting in reflected light N11, which is then reflected again at the screen. Reflected light N12 from the screen then re-enters the 50 / 50 semi-reflective and semi-transparent film layer. Light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer is reflected again, resulting in reflected light N13. Reflected light N13, which enters the eye-tracking camera module 102, constitutes the first path of stray light. In this application, stray light refers to light that is not desired to enter the eye-tracking camera module 102.

[0061] like Figure 3 As shown in the dashed box ②, the P-type linearly polarized light P2 reflected from the eyeball 104 is converted into left-handed circularly polarized light L1 after passing through the composite lens composed of RP and POL and the QWP. When incident on the 50 / 50 semi-reflective and semi-transparent film, 50% of the light cannot pass through the 50 / 50 semi-reflective and semi-transparent film. This causes the light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film to be reflected and converted into right-handed circularly polarized light R21. The right-handed circularly polarized light R21 is then converted into right-handed circularly polarized light R21 through the QWP. S-shaped linearly polarized light S11 is incident on the composite lens composed of RP and POL and is completely reflected to obtain reflected S-shaped linearly polarized light S12. S-shaped linearly polarized light S12 is converted into right-hand circularly polarized light R22 through QWP. 50% of the right-hand circularly polarized light R22, R23, passes through the 50 / 50 semi-reflective and semi-transparent film layer and is incident on the eye-tracking camera module 102. The right-hand circularly polarized light R23 is the second stray light.

[0062] Thus, the light collected by the eye-tracking camera module 102 includes both the left-hand circularly polarized light L2 to be collected and two stray lights, namely the reflected light R12 and the right-hand circularly polarized light R23, which affects the accuracy of eye-tracking recognition.

[0063] To address the aforementioned problems, this application proposes an optical device including an eye-tracking system. The eye-tracking system provided in this application, based on the placement of an infrared light source 101 between the screen of the MR device 100 and the optical component 103, adds corresponding polarization components to the light-emitting side (e.g., the light-emitting surface of the infrared light source 101) and the light-incident side (e.g., the light-incident and light-excident surfaces of the eye-tracking camera module 102), respectively. This ensures that the light emitted from the polarization component on the infrared light source 101 and the light transmitted through the polarization component on the eye-tracking camera module 102 are both circularly polarized, and their rotation directions are the same (e.g., both are left-handed circularly polarized, or both are right-handed circularly polarized). It can be understood that when the light emitted from the polarization component on the infrared light source 101 is circularly polarized, the rotation directions of the circularly polarized states of the two stray lights generated during light transmission are opposite to the rotation directions of the circularly polarized states of the light emitted from the polarization component on the infrared light source 101 (see below). Figure 4 and Figure 5 (Explanation of the light transmission process) Therefore, by setting the direction of the circular polarization state of the light transmitted by the polarization component on the eye-tracking camera module 102 to be the same as the direction of the circular polarization state of the light emitted by the polarization component on the infrared light source 101, the direction of the circular polarization state of the light transmitted by the polarization component on the eye-tracking camera module 102 can be opposite to the direction of the circular polarization state of the two stray lights, thus effectively blocking the two stray lights.

[0064] For example, a first polarization component 105 is provided on the light-emitting side of the infrared light source 101, and a second polarization component 106 is provided on the light-incident side of the eye-tracking camera module 102. When the light emitted from the infrared light source 101 is modulated by the first polarization component 105 and converted to a left-handed circularly polarized state, both stray lights generated during light transmission will be right-handed circularly polarized. When the polarization state of the light transmitted through the second polarization component 106 on the eye-tracking camera module 102 is also left-handed circularly polarized, the two right-handed circularly polarized stray lights will be blocked and will not be incident on the eye-tracking camera module 102. This improves the accuracy of the collected light.

[0065] For example, when the light emitted by the infrared light source 101 is modulated by the first polarization component 105 and converted to a right-handed circularly polarized state, the two stray lights generated during the light transmission process will both be left-handed circularly polarized. When the polarization state of the light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102 is also right-handed circularly polarized, the two stray lights in the left-handed circularly polarized state will be blocked and will not enter the eye-tracking camera module 102. This improves the accuracy of the collected light.

[0066] It is understood that in some embodiments, the first polarization component 105 may be disposed on the light-emitting surface of the infrared light source 101, for example, attached to the light-emitting surface of the infrared light source 101, or disposed on the light-emitting side of the infrared light source 101 at a predetermined distance from the light-emitting surface; this application does not impose any limitation. The second polarization component 106 may be disposed on the light-incident surface of the eye-tracking camera module 102, for example, attached to the light-incident surface of the eye-tracking camera module 102, or disposed on the light-incident side of the eye-tracking camera module 102 at a predetermined distance from the light-incident surface; this application does not impose any limitation.

[0067] The following section, using a structural example diagram of an eye-tracking system, explains the transmission path of the eye-tracking light beam and the principle behind the blocking of the two stray light beams.

[0068] Figure 4 Taking as an example that the type of light modulated by the first polarization component 105 on the infrared light source 101 and the type of light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102 are both left-handed circularly polarized light, a structural example diagram of an eye-tracking system 100 is illustrated. Figure 4 As shown, the eye-tracking system 100 includes an infrared light source 101, an eye-tracking camera module 102, and an optical component 103. The infrared light source 101 has a first polarization component 105 on its surface, and the eye-tracking camera module 102 has a second polarization component 106 on its surface. The optical component 103 includes a 50 / 50 semi-reflective film layer, a QWP (Quick Field Film), and a third polarization component, wherein the third polarization component consists of an AR (Augmented Reflection), RP (Reflection Point), and POL (Polypolarization). Both the infrared light source 101 and the eye-tracking camera module 102 are positioned between the optical component 103 and the screen of the MR (Mixed Reality) device.

[0069] Reference Figure 4 The light transmission path indicated by the middle arrow shows that when a first polarization component 105 is added to the surface of the infrared light source 101, the infrared light emitted from the infrared light source is converted into left-handed circularly polarized light L1 after passing through the first polarization component 105. Left-handed circularly polarized light L1 passes through a 50 / 50 semi-reflective and semi-transparent film layer and is converted into left-handed circularly polarized light L2. Left-handed circularly polarized light L2 passes through a QWP and is converted into P-type linearly polarized light P1. P-type linearly polarized light P1 passes through a third polarization component and is converted into P-type linearly polarized light P2. The P-type linearly polarized light P2 emitted into the eye region... P-type linearly polarized light P3 is obtained by reflection from the eye region 104. After passing through the third polarization component, P3 is converted into P-type linearly polarized light P4. After passing through the QWP, P4 is converted into left-handed circularly polarized light L3. The left-handed circularly polarized light L3 is converted into left-handed circularly polarized light L4 after passing through the 50 / 50 semi-reflective and semi-transparent film layer. Since the second polarization component 106 on the eye-tracking camera module 102 can transmit left-handed circularly polarized light, the left-handed circularly polarized light L4 is collected and absorbed by the second polarization component 106 of the eye-tracking camera module 102.

[0070] For the first stray light, due to the 50 / 50 semi-reflective and semi-transparent film layer's characteristic that the reflected and transmitted light each account for 50%, the infrared light emitted by the infrared light source 101 is converted into left-handed polarized light L1 after passing through the first polarization component 105. When the left-handed polarized light L1 is incident on the 50 / 50 semi-reflective and semi-transparent film layer, 50% of the left-handed polarized light L1 cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer. For example, as... Figure 4 As shown in the dashed box ①, light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer is reflected by the 50 / 50 semi-reflective and semi-transparent film layer to obtain right-hand circularly polarized light R11, which is then incident on the screen. At the screen, it is reflected again and converted into left-hand circularly polarized light L11. After the left-hand circularly polarized light L11 reflected from the screen is incident on the 50 / 50 semi-reflective and semi-transparent film layer again, there is still light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer. After being reflected by the 50 / 50 semi-reflective and semi-transparent film layer, it becomes right-hand circularly polarized light R12. When the right-hand circularly polarized light R12 (i.e., the first stray light) is incident on the eye-tracking camera module 102, since the second polarization component 106 on the eye-tracking camera module 102 can only transmit left-hand circularly polarized light, that is, it cannot transmit right-hand circularly polarized light R12, the right-hand circularly polarized light R12 will be blocked by the second polarization component 106 and will not be collected by the eye-tracking camera module 102.

[0071] For the second stray light, the P-type linearly polarized light P3 reflected from the eyeball is converted into left-handed circularly polarized light L3 after passing through the third polarization component and QWP. When incident on the 50 / 50 semi-reflective and semi-transparent film layer, some light rays will not be able to pass through the 50 / 50 semi-reflective and semi-transparent film layer, for example, such as... Figure 4 As shown in the dashed box ②, light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film is reflected and converted into right-hand circularly polarized light R21. After passing through the QWP, the right-hand circularly polarized light R21 is converted into S-shaped linearly polarized light S11. The S-shaped linearly polarized light S11 is reflected again by the composite lens composed of RP and POL and converted into S-shaped linearly polarized light S12. The S-shaped linearly polarized light S12 passes through the QWP again and is converted into right-hand circularly polarized light R22. Part of the right-hand circularly polarized light R22, R23, passes through the 50 / 50 semi-reflective and semi-transparent film. When the right-hand circularly polarized light R23 (i.e., the second stray light) is incident on the eye-tracking camera module 102, it will be blocked by the second polarization component 106 because the second polarization component 106 on the eye-tracking camera module 102 can only transmit left-hand circularly polarized light, that is, it cannot transmit right-hand circularly polarized light R23.

[0072] Thus, since the second polarization component 106 of the eye-tracking camera module 102 can transmit light with a left-handed circular polarization state, the two right-handed circularly polarized stray lights will be blocked and will not incident on the eye-tracking camera module 102. This improves the accuracy of the collected light.

[0073] Figure 5 Taking as an example that the type of light modulated by the first polarization component 105 on the infrared light source 101 and the type of light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102 are both right-handed circularly polarized light, a structural example diagram of an eye-tracking system is illustrated. Figure 5 As shown, the eye-tracking system 100 includes an infrared light source 101, an eye-tracking camera module 102, and an optical assembly 103. The infrared light source 101 has a first polarization component 105 on its surface, and the eye-tracking camera module 102 has a second polarization component 106 on its surface. The optical assembly 1031 includes a 50 / 50 semi-reflective film layer, a QWP (Quick Field Film), and a third polarization component, wherein the third polarization component is a polarizer assembly composed of AR (Augmented Reflection), RP (Reflection Plate), and POL (Polymerization Optical). Both the infrared light source 101 and the eye-tracking camera module 102 are placed between the optical assembly 103 and the screen of the MR device.

[0074] Reference Figure 5 The light transmission path indicated by the middle arrow shows that when a first polarization component 105 is added to the surface of the infrared light source 101, the infrared light emitted from the infrared light source is converted into right-handed circularly polarized light R1 after passing through the first polarization component 105. Right-handed circularly polarized light R1 passes through a 50 / 50 semi-reflective and semi-transparent film layer and is converted into right-handed circularly polarized light R2. Right-handed circularly polarized light R2 passes through a QWP and is converted into P-type linearly polarized light P1. P-type linearly polarized light P1 passes through a third polarization component and is converted into P-type linearly polarized light P2. The P-type linearly polarized light P2 emitted into the eye region... P-type linearly polarized light P3 is obtained by reflection from the eye region 104. After passing through the third polarization component, P3 is converted into P-type linearly polarized light P4. After passing through the QWP, P4 is converted into right-hand circularly polarized light R3. R3 passes through the 50 / 50 semi-reflective and semi-transparent film layer and is converted into right-hand circularly polarized light R4. Since the second polarization component 106 on the eye-tracking camera module 102 can transmit right-hand circularly polarized light, R4 is collected and absorbed by the second polarization component 106 of the eye-tracking camera module 102.

[0075] For the first stray light, due to the 50 / 50 semi-reflective and semi-transparent film layer's characteristic that the reflected and transmitted light each account for 50%, the infrared light emitted by the infrared light source 101 is converted into right-handed polarized light R1 after passing through the first polarization component 105. When the right-handed polarized light R1 is incident on the 50 / 50 semi-reflective and semi-transparent film layer, 50% of the right-handed polarized light R1 cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer. For example, as... Figure 5As shown in the dashed box ①, light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer is reflected by the 50 / 50 semi-reflective and semi-transparent film layer to obtain left-handed circularly polarized light L11, which is then incident on the screen. At the screen, it is reflected again and converted into right-handed circularly polarized light R11. After the right-handed circularly polarized light R11 reflected from the screen is incident on the 50 / 50 semi-reflective and semi-transparent film layer again, there is still light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film layer. After being reflected by the 50 / 50 semi-reflective and semi-transparent film layer, it becomes left-handed circularly polarized light L12. When the left-handed circularly polarized light L12 (i.e., the first stray light) is incident on the eye-tracking camera module 102, since the second polarization component 106 on the eye-tracking camera module 102 can only transmit right-handed circularly polarized light, that is, it cannot transmit left-handed circularly polarized light L12, the left-handed circularly polarized light L12 will be blocked by the second polarization component 106 and will not be collected by the eye-tracking camera module 102.

[0076] For the second stray light, the P-type linearly polarized light P3 reflected from the eyeball is converted into right-handed circularly polarized light R3 after passing through the third polarization component and QWP. When incident on the 50 / 50 semi-reflective and semi-transparent film layer, some light rays will not be able to pass through the 50 / 50 semi-reflective and semi-transparent film layer, for example, such as... Figure 5 As shown in the dashed box ②, light that cannot pass through the 50 / 50 semi-reflective and semi-transparent film is reflected and converted into left-handed circularly polarized light L21. After passing through the QWP, the left-handed circularly polarized light L21 is converted into S-shaped linearly polarized light S11. The S-shaped linearly polarized light S11 is incident on the third polarization component and reflected again, converting into S-shaped linearly polarized light S12. The S-shaped linearly polarized light S12 passes through the QWP again and is converted into left-handed circularly polarized light L22. Part of the left-handed circularly polarized light L22, L23, passes through the 50 / 50 semi-reflective and semi-transparent film and is incident on the eye-tracking camera module 102. Since the second polarization component 106 on the eye-tracking camera module 102 can only transmit right-handed circularly polarized light, that is, it cannot transmit left-handed circularly polarized light L23, the left-handed circularly polarized light L23 will be blocked by the second polarization component 106.

[0077] Thus, since the second polarization component 106 of the eye-tracking camera module 102 allows light to pass through in a right-handed circularly polarized state, the two stray lights L12 and L23 will be blocked and will not incident on the eye-tracking camera module 102. This improves the accuracy of the collected light.

[0078] It should be noted that the above Figures 4-5 The first polarization component 105, the second polarization component 106, the 50 / 50 semi-reflective and semi-transparent film layer, the QWP, and the third polarization component shown can all be designed with any structural form according to actual functions to meet the requirements. Figures 4-5 Optical transmission in the process.

[0079] The structure of the first polarization component 105 disposed on the surface of the infrared light source 101 and the second polarization component 106 disposed on the surface of the eye-tracking camera module 102 will be described by way of example below.

[0080] Figure 6A A schematic diagram of the structure of a first polarization component 105 disposed on the surface of an infrared light source 101 is shown, as follows: Figure 6A As shown, the first polarization component 105 includes a first QWP and a first POL. The first surface of the first POL is connected to the light-emitting surface of the infrared light source 101, and the second surface of the first POL is connected to the first QWP. The first surface and the second surface of the first POL are two opposite surfaces of the first POL.

[0081] In some embodiments, the first POL is used to convert the light emitted by the infrared light source into linearly polarized light and transmit the linearly polarized light to the first QWP, which is used to convert the linearly polarized light into left-handed or right-handed circularly polarized light.

[0082] In some embodiments, the linearly polarized light transmitted by the first POL can be converted into left-handed or right-handed circularly polarized light by matching the angle of the transmission axis of the first POL and the angle of the slow axis of the first QWP. For example, if the difference between the angle of the transmission axis of the first POL and the angle of the slow axis of the first QWP is -45 degrees, the linearly polarized light transmitted by the first POL can be converted into left-handed circularly polarized light. If the difference between the angle of the transmission axis of the first POL and the angle of the slow axis of the first QWP is 45 degrees, the linearly polarized light transmitted by the first POL can be converted into right-handed circularly polarized light.

[0083] For example, for those that need to be implemented Figure 4 The light transmitted through the first polarization component 105 shown is left-handed circularly polarized light L1. The transmission axis angle of the first POL can be set to 90 degrees and the slow axis angle of the first QWP can be set to 135 degrees. Then the first POL is used to convert the natural light N1 emitted by the infrared light source 101 into P-type linearly polarized light P0 through the first POL on the first polarization component 105, and the first QWP is used to convert the P-type linearly polarized light P0 into left-handed circularly polarized light L1.

[0084] For example, for those that need to be implemented Figure 4 The light transmitted through the first polarization component 105 shown is left-handed circularly polarized light L1. The transmission axis angle of the first POL can be set to 0 degrees and the slow axis angle of the first QWP can be set to 45 degrees. Then the first POL is used to convert the natural light N1 emitted by the infrared light source 101 into S-type linearly polarized light S0 through the first POL on the first polarization component 105, and the first QWP is used to convert the S-type linearly polarized light S0 into left-handed circularly polarized light L1.

[0085] For example, for those that need to be implemented Figure 5 The light transmitted through the first polarization component 105 shown is right-hand circularly polarized light R1. The transmission axis angle of the first POL can be set to 90 degrees and the slow axis angle of the first QWP can be set to 45 degrees. Then the first POL is used to convert the natural light N1 emitted by the infrared light source 101 into P-type linearly polarized light P0 through the first POL on the first polarization component 105, and the first QWP is used to convert the P-type linearly polarized light P0 into right-hand circularly polarized light R1.

[0086] For example, for those that need to be implemented Figure 5 The light transmitted through the first polarization component 105 shown is right-hand circularly polarized light R1. The transmission axis angle of the first POL can be set to 0 degrees and the slow axis angle of the first QWP can be set to -45°. Then the first POL is used to convert the natural light N1 emitted by the infrared light source 101 into S-type linearly polarized light S0 through the first POL on the first polarization component 105, and the first QWP is used to convert the S-type linearly polarized light S0 into right-hand circularly polarized light R1.

[0087] Figure 6B A schematic diagram of the structure of a second polarization component 106 disposed on the surface of an eye-tracking camera module 102 is shown, as follows: Figure 6B As shown, the second polarization component 106 includes a second POL and a second QWP. The first surface of the second POL is connected to the light-incident surface of the eye-tracking camera module 102, and the second surface of the second POL is connected to the second QWP. The first surface of the second POL and the second surface of the second POL are two opposite surfaces of the second POL.

[0088] In some embodiments, the second POL and the second QWP can be matched to block left-handed or right-handed circularly polarized light from incident on the eye-tracking camera module 102. For example, the second QWP can be used to convert first-direction circularly polarized light transmitted from the optical component into first-type linearly polarized light, and to convert second-direction circularly polarized light transmitted from the optical component into second-type linearly polarized light; the second POL can be used to transmit the first-type linearly polarized light to the eye-tracking camera module 102, and to block the second-type linearly polarized light. It is understood that the first-direction circularly polarized light has the same direction of rotation as the circularly polarized light modulated and transmitted by the first polarization component 105.

[0089] For example, for those that need to be implemented Figure 5The method shown blocks left-handed circularly polarized light from entering the eye-tracking camera module 102. The slow axis of the second QWP can be set to 45 degrees, and the transmission axis of the second POL can be set to 90 degrees. The second QWP converts left-handed circularly polarized light transmitted from the optical component 100 into P-type linearly polarized light, and converts right-handed circularly polarized light transmitted from the optical component into S-type linearly polarized light. The second POL transmits P-type polarized light to the eye-tracking camera module 102 and blocks S-type linearly polarized light. In other words, the combination of the second POL and the second QWP converts left-handed circularly polarized light into P-type linearly polarized light, which is then incident on the eye-tracking camera module 102, while right-handed circularly polarized light is converted into S-type linearly polarized light and blocked by the second POL.

[0090] For example, for those that need to be implemented Figure 5 The method shown blocks left-handed circularly polarized light from entering the eye-tracking camera module 102. The slow axis of the second QWP can be set to 135 degrees, and the transmission axis of the second POL can be set to 0 degrees. The second QWP can be used to convert left-handed circularly polarized light transmitted from the optical components into S-type linearly polarized light, and to convert right-handed circularly polarized light transmitted from the optical components into P-type linearly polarized light. The second POL is used to transmit S-type polarized light to the eye-tracking camera module 102 and to block P-type linearly polarized light. In other words, the combination of the second POL and the second QWP causes left-handed circularly polarized light to be converted into S-type linearly polarized light and enter the eye-tracking camera module 102, while right-handed circularly polarized light is converted into P-type linearly polarized light and blocked by the second POL.

[0091] For example, for those that need to be implemented Figure 4 The method shown blocks right-handed circularly polarized light from entering the eye-tracking camera module 102. The slow axis of the second QWP can be set to 45 degrees, and the transmission axis of the second POL can be set to 0 degrees. The second QWP is used to convert left-handed circularly polarized light transmitted from the optical components into P-type linearly polarized light, and to convert right-handed circularly polarized light transmitted from the optical components into S-type linearly polarized light. The second POL is used to transmit S-type polarized light to the eye-tracking camera module 102, and to block P-type linearly polarized light. In other words, the combination of the second POL and the second QWP converts right-handed circularly polarized light into S-type linearly polarized light, which is then incident on the eye-tracking camera module 102, while left-handed circularly polarized light is converted into P-type linearly polarized light and blocked by the second POL.

[0092] For example, for applications requiring blocking Figure 4The right-hand circularly polarized light shown is incident on the eye-tracking camera module 102. The slow axis of the second QWP can be set to 135 degrees, and the transmission axis of the second POL can be set to 90 degrees. The second QWP can be used to convert left-hand circularly polarized light transmitted from the optical components into S-type linearly polarized light, and to convert right-hand circularly polarized light transmitted from the optical components into P-type linearly polarized light. The second POL is used to transmit P-type polarized light to the eye-tracking camera module 102, and to block S-type linearly polarized light. That is, the combination of the second POL and the second QWP causes right-hand circularly polarized light to be converted into P-type linearly polarized light and incident on the eye-tracking camera module 102, while left-hand circularly polarized light is converted into S-type linearly polarized light and blocked by the second POL.

[0093] It is understood that the first polarization component 105 and the second polarization component 106 can be arbitrarily combined according to actual needs to achieve the goal of ensuring that the type of light modulated by the first polarization component 105 on the infrared light source 101 is circularly polarized with the same direction of rotation as the type of light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102.

[0094] It is understood that the components in the optical assembly 103 can also be adjusted for matching according to the types of the first polarization assembly 105 and the second polarization assembly 106, in order to achieve the desired results. Figures 4-5 The optical path transmission requirements are shown in the figure.

[0095] Figure 7A Taking as an example that the type of light modulated by the first polarization component 105 set on the surface of the infrared light source 101 and the type of light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102 are both left-handed circularly polarized light, a structural schematic diagram and an optical path transmission schematic diagram of an eye-tracking system 100 are shown.

[0096] like Figure 7A As shown, the eye-tracking system 100 includes an infrared light source 101, an eye-tracking camera module 102, and an optical component 103. A first polarization component 105 is disposed on the surface of the infrared light source 101, and a second polarization component 106 is disposed on the surface of the eye-tracking camera module 102. The first polarization component 105 includes a first QWP and a first POL. The transmission axis angle of the first POL on the first polarization component 105 is 90°, the slow axis angle of the first QWP is 135°, and the difference between the transmission axis angle of the first POL and the slow axis angle of the first QWP is -45 degrees. The second polarization component 106 includes a second POL and a second QWP. The slow axis of the second QWP is 45 degrees, and the transmission axis of the second POL is 90 degrees.

[0097] like Figure 7AThe optical transmission path indicated by the middle arrow shows that the natural light N1 emitted from the infrared light source 101 is converted into P-type linearly polarized light P0 by the first POL on the polarization component 105. The P-type linearly polarized light P0 is then converted into left-handed circularly polarized light L1 by the first QWP. The left-handed circularly polarized light L1 then... Figure 4 The optical component 103 shown transmits light to the eyeball. The light reflected from the eyeball is transmitted through the optical component 103 and converted into left-hand circularly polarized light L4, which is then incident on the second QWP. After passing through the second QWP, the left-hand circularly polarized light L4 is converted into P-type linearly polarized light P01. After passing through the second POL, the P-type linearly polarized light P01 is collected and absorbed by the eye-tracking camera module 102.

[0098] It is understandable that, in order to achieve optical path matching, the slow axis of QWP in optical component 103 can be set to 45°, the transmission axis of POL can be set to 90°, and the reflection axis of RP can be set to 0°.

[0099] Understandable. Figure 7A The second polarization component 106 of the eye-tracking camera module 102 shown can transmit light with a left-hand circular polarization state. Stray light with two right-hand circular polarization states will be blocked and will not be incident on the eye-tracking camera module 102.

[0100] Figure 7B Taking the type of light modulated by the first polarization component 105 set on the surface of the infrared light source 101 and the type of light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102 as an example, a structural schematic diagram and optical path transmission schematic diagram of another eye-tracking system 100 are shown.

[0101] like Figure 7B As shown, the eye-tracking system 100 includes an infrared light source 101, an eye-tracking camera module 102, and an optical component 103. A first polarization component 105 is disposed on the surface of the infrared light source 101, and a second polarization component 106 is disposed on the surface of the eye-tracking camera module 102. The first polarization component 105 includes a first QWP and a first POL. The transmission axis angle of the first POL on the first polarization component 105 is 0°, the slow axis angle of the first QWP is 45°, and the difference between the transmission axis angle of the first POL and the slow axis angle of the first QWP is -45 degrees. The second polarization component 106 includes a second POL and a second QWP. The slow axis of the second QWP is 135 degrees, and the transmission axis of the second POL is 0 degrees.

[0102] like Figure 7BThe optical transmission path indicated by the middle arrow shows that the natural light N1 emitted from the infrared light source 101 is converted into S-shaped linearly polarized light S0 by the first POL on the first polarization component 105. The S-shaped linearly polarized light S0 is then converted into left-handed circularly polarized light L1 by the first QWP. The left-handed circularly polarized light L1 then... Figure 4 The optical component 103 shown transmits light to the eyeball, and the light reflected from the eyeball passes through... Figure 4 The optical component 103 shown transmits and converts the light into left-handed circularly polarized light L4, which is then incident on the second QWP. After passing through the second QWP, the left-handed circularly polarized light L4 is converted into S-shaped linearly polarized light S01. The S-shaped linearly polarized light S01 passes through the second POL and is then collected and absorbed by the eye-tracking camera module 102.

[0103] It is understandable that, in order to achieve optical path matching, the slow axis of QWP in optical component 103 can be set to 45°, the transmission axis of POL can be set to 90°, and the reflection axis of RP can be set to 0°.

[0104] Understandable. Figure 7B The second polarization component 106 of the eye-tracking camera module 102 shown can transmit light with a left-hand circular polarization state. Stray light with two right-hand circular polarization states will be blocked and will not be incident on the eye-tracking camera module 102.

[0105] Figure 7C Taking the type of light modulated by the first polarization component 105 set on the surface of the infrared light source 101 and the type of light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102 as an example, a schematic diagram of the optical path transmission of an eye-tracking system is shown.

[0106] like Figure 7C As shown, the eye-tracking system 100 includes an infrared light source 101, an eye-tracking camera module 102, and an optical component 103. A first polarization component 105 is disposed on the surface of the infrared light source 101, and a second polarization component 106 is disposed on the surface of the eye-tracking camera module 102. The polarization component 105 includes a first QWP and a first POL. The transmission axis of the first POL is at an angle of 90 degrees, the slow axis of the first QWP is at an angle of 45 degrees, and the difference between the transmission axis angle of the first POL and the slow axis angle of the first QWP is 45 degrees. The second polarization component 106 includes a second POL and a second QWP. The slow axis of the second QWP is 45 degrees, and the transmission axis of the second POL is 0 degrees.

[0107] like Figure 7CThe optical transmission path indicated by the middle arrow shows that the natural light N1 emitted from the infrared light source 101 is converted into P-type linearly polarized light P0 by the first POL on the first polarization component 105. The P-type linearly polarized light P0 is then converted into right-hand circularly polarized light R1 by the first QWP. The right-hand circularly polarized light R1 then... Figure 4 The optical component 103 shown transmits light to the eyeball, and the light reflected from the eyeball passes through... Figure 4 The optical component 103 shown transmits and converts right-hand circularly polarized light R4 into light incident on the second QWP. After passing through the second QWP, the right-hand circularly polarized light R4 is converted into S-shaped linearly polarized light S01. The S-shaped linearly polarized light S01 passes through the second POL and is collected and absorbed by the eye-tracking camera module 102.

[0108] It is understandable that, in order to achieve optical path matching, the slow axis of QWP in optical component 103 can be set to 135°, the transmission axis of POL can be set to 90°, and the reflection axis of RP can be set to 0°.

[0109] Understandable. Figure 7C The second polarization component 106 of the eye-tracking camera module 102 shown can transmit right-hand circularly polarized light, while the two left-hand circularly polarized stray lights will be blocked and will not be incident on the eye-tracking camera module 102.

[0110] Figure 7D Taking the type of light modulated by the first polarization component 105 set on the surface of the infrared light source 101 and the type of light that can be transmitted by the second polarization component 106 on the eye-tracking camera module 102 as an example, a schematic diagram of the optical path transmission of an eye-tracking system is shown.

[0111] like Figure 7D As shown, the eye-tracking system 100 includes an infrared light source 101, an eye-tracking camera module 102, and an optical component 103. A first polarization component 105 is disposed on the surface of the infrared light source 101, and a second polarization component 106 is disposed on the surface of the eye-tracking camera module 102. The polarization component 105 includes a first QWP and a first POL. The transmission axis angle of the first POL on the polarization component 105 is 0 degrees, the slow axis angle of the first QWP is -45°, and the difference between the transmission axis angle of the first POL and the slow axis angle of the first QWP is 45 degrees. The second polarization component 106 includes a second POL and a second QWP. The slow axis of the second QWP is 135 degrees, and the transmission axis of the second POL is 90 degrees.

[0112] like Figure 7DThe optical transmission path indicated by the middle arrow shows that the natural light N1 emitted from the infrared light source 101 is converted into S-type linearly polarized light S0 by the first POL on the first polarization component 105. The S-type linearly polarized light S0 is then converted into right-hand circularly polarized light R1 by the first QWP. The right-hand circularly polarized light R1 then... Figure 4 The optical component 103 shown transmits light to the eyeball, and the light reflected from the eyeball passes through... Figure 4 The optical component 103 shown transmits and converts right-hand circularly polarized light R4 into light incident on the second QWP. After passing through the second QWP, the right-hand circularly polarized light R4 is converted into P-type linearly polarized light P01. The P-type linearly polarized light P01 passes through the second POL and is collected and absorbed by the eye-tracking camera module 102.

[0113] It is understandable that, in order to achieve optical path matching, the slow axis of QWP in optical component 103 can be set to 135°, the transmission axis of POL can be set to 90°, and the reflection axis of RP can be set to 0°.

[0114] Understandable. Figure 7D The second polarization component 106 of the eye-tracking camera module 102 shown can transmit right-hand circularly polarized light, while the two left-hand circularly polarized stray lights will be blocked and will not be incident on the eye-tracking camera module 102.

[0115] In some embodiments, the first polarization component 105 and the second polarization component 106 mentioned in this application may be optical composite films or corresponding micro / nano structure elements that conform to the functions of the first polarization component 105 and the second polarization component 106 provided in this application.

[0116] In summary, the eye-tracking system of the optical device provided in this application embodiment can effectively block stray light from entering the eye-tracking camera module, thereby improving the accuracy of eye tracking.

[0117] In some embodiments, the 50 / 50 semi-reflective and semi-transparent film layer can be set to have a transmittance of 49%-51% for visible light, for example, 50%, and a transmittance of greater than or equal to 99% for light emitted by the infrared light source 101 (e.g., 850nm), that is, to increase the transmittance of near-infrared light, thereby further effectively reducing the generation of stray light.

[0118] Table 1 illustrates an example of the component structure of a 50 / 50 semi-reflective and semi-permeable membrane layer. Table 1: Component Structure of a 50 / 50 Semi-reflective and Semi-permeable Membrane Layer

[0119] Serial Number Thickness dimension (nm) Material composition 1 19.693 <![CDATA[TiO2]]> 2 14.791 <![CDATA[SiO2]]> 3 112.125 <![CDATA[TiO2]]> 4 16.637 <![CDATA[SiO2]]> 5 21.654 <![CDATA[TiO2]]> 6 278.605 <![CDATA[SiO2]]> 7 203.393 <![CDATA[SiO2]]> 8 45.571 <![CDATA[TiO2]]> 9 48.908 <![CDATA[SiO2]]> 10 97.335 <![CDATA[TiO2]]> 11 225.788 <![CDATA[SiO2]]> 12 133.286 <![CDATA[TiO2]]> 13 151.648 <![CDATA[SiO2]]> 14 9.152 <![CDATA[TiO2]]> 15 37.855 <![CDATA[SiO2]]> 16 80.844 <![CDATA[SiO2]]>

[0120] As shown in Table 1, the semi-reflective and semi-transparent film layer may include a first TiO2 layer, a first SiO2 layer, a second TiO2 layer, a second SiO2 layer, a third TiO2 layer, a third SiO2 layer, a fourth SiO2 layer, a fourth TiO2 layer, a fifth SiO2 layer, a fifth TiO2 layer, a sixth SiO2 layer, a sixth TiO2 layer, a seventh SiO2 layer, a seventh TiO2 layer, an eighth SiO2 layer, and a ninth SiO2 layer. The thicknesses of the first TiO2 layer, the first SiO2 layer, the second TiO2 layer, the second SiO2 layer, the third TiO2 layer, the third SiO2 layer, the fourth SiO2 layer, the fourth TiO2 layer, the fifth SiO2 layer, the fifth TiO2 layer, the sixth SiO2 layer, the sixth TiO2 layer, the seventh SiO2 layer, the seventh TiO2 layer, the eighth SiO2 layer, and the ninth SiO2 layer are 19.693nm, 14.791nm, 112.125nm, 16.637nm, 21.654nm, 278.605nm, 203.393nm, 45.571nm, 48.908nm, 97.335nm, 225.788nm, 133.286nm, 151.648nm, 9.152nm, 37.855nm, and 80.844nm, respectively.

[0121] When TiO2 and SiO2 are arranged in the above order and thickness, a solid film can be formed by chemical vapor deposition, that is, a 50 / 50 semi-reflective and semi-permeable film layer is formed.

[0122] The above embodiments are merely illustrative examples of this application. By setting specific thicknesses and stacking orders for TiO2 and SiO2 materials, the above-mentioned reflectivity effect of the 50 / 50 semi-reflective and semi-transparent film layer can be achieved. The specific method of implementation is not limited here, and all are within the protection scope of this application.

[0123] Figure 8A The reflectance spectrum of a 50 / 50 semi-reflective and semi-transparent film layer based on the structure shown in Table 1 is shown. Figure 8A The horizontal axis of the reflectance spectrum represents the wavelength of light passing through the 50 / 50 semi-reflective and semi-transparent film layer, and the vertical axis represents the reflectance of light passing through the 50 / 50 semi-reflective and semi-transparent film layer at the corresponding wavelength. Figure 8A As shown, the 50 / 50 semi-reflective and semi-transparent film has a reflectivity of 49-51% for visible light (380nm-780nm), which is approximately 50%. Therefore, the 50 / 50 semi-reflective and semi-transparent film has a semi-reflective and semi-transparent effect for visible light (380nm-780nm). The reflectivity near the 850nm wavelength emitted by the infrared light source 101 is less than 0.1%, meaning the 50 / 50 semi-reflective and semi-transparent film maintains a transmittance of over 99.00% near the light emitted by the infrared light source 101.

[0124] It is understandable that when the wavelength of the light emitted by the infrared light source 101 is other wavelengths, the same reflectivity and transmittance of the 50 / 50 semi-reflective and semi-transparent film layer to the light emitted by the infrared light source 101 can be achieved by setting specific thicknesses and stacking orders of the two materials TiO2 and SiO2.

[0125] In some embodiments, the reflectivity of the AR film to visible light can be set to less than 0.60%, and the reflectivity of the AR film to light emitted by the infrared light source 101 (e.g., 850nm) can be set to less than 0.25%. In this way, the light transmittance can be guaranteed, that is, the intensity of light incident on the eyeball and the intensity of light reflected from the eyeball incident on the eye-tracking camera module 102 can be guaranteed, thereby improving the accuracy of eye tracking.

[0126] Table 2 shows an example diagram of the composition of AR film components.

[0127] Table 2: Composition of AR film components

[0128] Serial Number Thickness dimension (nm) Material composition 1 16.839 <![CDATA[TiO2]]> 2 28.526 <![CDATA[SiO2]]> 3 130.217 <![CDATA[SiO2]]> 4 35.163 <![CDATA[SiO2]]> 5 15.444 <![CDATA[TiO2]]> 6 118.259 <![CDATA[SiO2]]> 7 12.74 <![CDATA[TiO2]]> 8 40.116 <![CDATA[SiO2]]> 9 125.94 <![CDATA[TiO2]]> 10 40.478 <![CDATA[SiO2]]> 11 12.299 <![CDATA[TiO2]]> 12 120.623 <![CDATA[SiO2]]> 13 16.094 <![CDATA[TiO2]]> 14 32.998 <![CDATA[SiO2]]> 15 75.291 <![CDATA[TiO2]]> 16 11.454 <![CDATA[SiO2]]> 17 31.711 <![CDATA[TiO2]]> 18 102.031 <![CDATA[SiO2]]>

[0129] As shown in Table 2, the AR film layer may include a first TiO2 layer, a first SiO2 layer, a second SiO2 layer, a third SiO2 layer, a second TiO2 layer, a fourth SiO2 layer, a third TiO2 layer, a fifth SiO2 layer, a fourth TiO2 layer, a sixth SiO2 layer, a fifth TiO2 layer, a seventh SiO2 layer, a sixth TiO2 layer, an eighth SiO2 layer, a seventh TiO2 layer, a ninth SiO2 layer, an eighth TiO2 layer, and a tenth SiO2 layer. The thicknesses of the first TiO2 layer, the first SiO2 layer, the second SiO2 layer, the third SiO2 layer, the second TiO2 layer, the fourth SiO2 layer, the third TiO2 layer, the fifth SiO2 layer, the fourth TiO2 layer, the sixth SiO2 layer, the fifth TiO2 layer, the seventh SiO2 layer, the sixth TiO2 layer, the eighth SiO2 layer, the seventh TiO2 layer, the ninth SiO2 layer, the eighth TiO2 layer, and the tenth SiO2 layer are all 16.83 mm. 9m, 28.526nm, 130.217nm, 35.163nm, 15.444nm, 118.259nm, 12.74nm, 40.116nm, 125.94nm, 40. 478nm, 12.299nm, 120.623nm, 16.094nm, 32.998nm, 75.291nm, 11.454nm, 31.711nm, 102.031nm.

[0130] TiO2 and SiO2 materials are arranged in the above order and thickness. A gaseous or liquid reactant is introduced through chemical vapor deposition to cause a chemical reaction on the surface of the materials, thereby forming a solid film, i.e., an AR film layer.

[0131] The above embodiments are merely illustrative examples of this application. By setting specific thicknesses and stacking orders for TiO2 and SiO2 materials, the above-mentioned reflectivity effect of the AR film can be achieved. The specific implementation method is not limited here, and all are within the protection scope of this application.

[0132] Figure 8B The reflectance spectrum of an AR film layer in an eye-tracking system is shown. The horizontal axis of the reflectance spectrum represents the wavelength of light passing through the AR film layer, and the vertical axis represents the reflectance of light passing through the AR film layer at the corresponding wavelength. Figure 8B As shown, the AR film has a reflectivity of less than 0.60% in the visible light region (380nm-780nm) and a reflectivity of less than 0.25% near the light emitted by the infrared light source 101 (wavelength 850nm), meaning that the transmittance near the light emitted by the infrared light source 101 (wavelength 850nm) is greater than 99.75%. This ensures the intensity of light incident on the eyeball and the intensity of light reflected from the eyeball incident on the eye-tracking camera module 102, improving the accuracy of eye tracking.

[0133] It is understandable that when the wavelength of the light emitted by the infrared light source 101 is other wavelengths, the reflectivity of the AR film to visible light can be less than 0.60% and the reflectivity to the light emitted by the infrared light source 101 can be less than 0.25% by setting specific thicknesses and stacking orders of the two materials, TiO2 and SiO2.

[0134] It is understood that the optical component 103 mentioned in the embodiments of this application can also be used for imaging of optical devices.

[0135] Figure 9 based on Figure 4 The eye-tracking system 100 shown illustrates a schematic diagram of the optical path transmission for imaging, as follows: Figure 9 As shown by the dashed line, the screen emits right-handed circularly polarized light R11. R11 passes through a 50 / 50 semi-reflective film and is converted into right-handed circularly polarized light R12. R12 then passes through a QWP (Quick Field Tester) and is converted into S-shaped linearly polarized light S11. S11 is then converted into S-shaped linearly polarized light S12 after passing through a third polarization component and reflected back to the QWP. S12 is then converted into right-handed circularly polarized light R13 after passing through the QWP. R13 is reflected by the 50 / 50 semi-reflective film and converted into left-handed circularly polarized light L11. L11 passes through the QWP and is converted into P-shaped linearly polarized light P11. P11 is then converted into P-shaped linearly polarized light P12 after passing through a third polarization component and is then captured by the human eye. The screen's emission wavelength only covers the 380nm-780nm range and does not involve the near-infrared band, thus avoiding interference with eye-tracking signal acquisition.

[0136] In summary, the eye-tracking system of the optical device provided in this application embodiment can effectively block stray light from entering the eye-tracking camera module, thereby improving the accuracy of eye tracking.

[0137] The specific embodiments described above illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with some embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details have been omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0138] In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "outer", "inner", "circumferential", "radial", "axial", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0139] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set," "install," "connect," and "fit" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0140] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. An optical device, characterized in that, Includes a light source, optical components, an eye-tracking camera module, a first polarization component, and a second polarization component: The first polarization component is disposed on the light-emitting side of the light source. The first polarization component is used to convert the first light emitted by the light source into a second light and to incident the second light onto the optical component, wherein the second light is circularly polarized light with a first rotation direction. The second polarization component is disposed on the light-incident side of the camera module. The second polarization component is used to transmit the first-rotation circularly polarized light transmitted by the optical component and to block the second-rotation circularly polarized light transmitted by the optical component. The second rotation direction is opposite to the first rotation direction.

2. The optical device according to claim 1, characterized in that, The first polarization component is disposed on the light-emitting surface of the light source, and the second polarization component is disposed on the light-incident surface of the eye-tracking camera module.

3. The optical device according to claim 1, characterized in that, The first direction of rotation is left-handed, and the second direction of rotation is right-handed; Alternatively, the first direction of rotation is right-handed, and the second direction of rotation is left-handed.

4. The optical device according to claim 2, characterized in that, The first polarization component includes a first QWP and a first POL, and the light-emitting surface of the light source and the first QWP are located on opposite sides of the first POL, respectively. The second polarization component includes a second POL and a second QWP, with the light incident surface of the camera module and the second QWP located on opposite sides of the second POL, respectively.

5. The optical device according to claim 4, characterized in that, The first POL is used to convert the first light ray into a third light ray and to transmit the third light ray to the first QWP. The first QWP is used to convert the third light ray into a second light ray, wherein the third light ray is linearly polarized light.

6. The optical device according to claim 4, characterized in that, The second QWP is used to convert the first-rotation circularly polarized light transmitted by the optical component into linearly polarized light with a first polarization direction, and to convert the second-rotation circularly polarized light transmitted by the optical component into linearly polarized light with a second polarization direction. The second POL is used to transmit linearly polarized light in the first polarization direction and to block linearly polarized light in the second polarization direction.

7. The optical device according to claim 1, characterized in that, The optical device also includes a screen; Along the first direction, the light source and the eye-tracking camera module are disposed between the screen and the optical component; and the light emission direction of the screen is toward the optical component.

8. The optical device according to any one of claims 1-7, characterized in that, The optical components include a semi-reflective and semi-transparent film layer disposed along a first direction, a third QWP, and a third polarization component; The third polarization component includes an AR, a third POL, and an RP arranged sequentially along the first direction.

9. The optical device according to claim 8, characterized in that, The light source is a near-infrared light source; The semi-reflective and semi-transparent film layer has a transmittance of 49%-51% for visible light and a transmittance of greater than or equal to 99% for near-infrared light emitted by the light source.

10. The optical device according to claim 8, characterized in that, The light source is a near-infrared light source; The AR has a reflectivity of less than 0.60% for visible light, and the semi-reflective and semi-transparent film layer has a reflectivity of less than 0.25% for near-infrared light emitted by the light source.

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