Head-mounted display and display module for same

Abstract

A head-mounted display (200) and a display module (10). The display module comprises: an infrared emitter (11); an imaging device (12); a color combining prism (13), comprising a first surface and a second surface opposite to each other; a polarization reflection assembly (14) arranged in the color combining prism, wherein the polarization reflection assembly (14) is used for guiding infrared light incident from the first surface to exit from a third surface of the color combining prism (13) and guiding infrared light reflected by a human eye to exit from the second surface; and at least one visible light-emitting panel (15), the color combining prism (13) being used for deflecting light emitted by the visible light-emitting panel and enabling the light to exit from the third surface to image in the human eye.

Description

Head-mounted display and display module for head-mounted display

[0001] Priority information

[0002] This application claims priority and benefits to patent application No. 202411566631.X, filed with the China National Intellectual Property Administration on November 4, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of extended reality technology, and more specifically, to a head-mounted display and a display module for the head-mounted display. Background Technology

[0004] Currently, in Extended Reality (XR), eye tracking is generally performed using iris reflection. This involves using an infrared LED light source (Light Emitting Diode) to illuminate and mark the human eye, and then using an infrared camera to take a picture of the human eye in order to track eye movements.

[0005] However, due to the limited field of view of infrared cameras, the iris reflection method generally requires two cameras to acquire images, resulting in a large display device size. Summary of the Invention

[0006] This application provides a head-mounted display and a display module for the head-mounted display, which can reduce the size of the device used for eye tracking.

[0007] The display module of this application includes: an infrared emitter configured to emit infrared light; an imaging device configured to receive infrared light reflected from the human eye for imaging; a color-combining prism, the color-combining prism including a first surface and a second surface, the first surface and the second surface being opposite each other, the infrared emitter being disposed opposite the first surface, and the imaging device being disposed opposite the second surface; a polarization reflection component disposed within the color-combining prism, the polarization reflection component being used to guide infrared light incident from the first surface to exit from a third surface of the color-combining prism, and to guide infrared light reflected from the human eye to exit from the second surface; and at least one visible light emitting panel disposed on a surface other than the first surface, second surface and third surface of the color-combining prism, the color-combining prism being used to deflect the light emitted by the visible light emitting panel and to exit from the third surface for imaging in the human eye.

[0008] In some embodiments, the visible light emitting panel includes a first visible light emitting panel, a second visible light emitting panel, and a third visible light emitting panel, which are configured to emit light of different wavelengths. The color combining prism further includes a fourth surface, a fifth surface, and a sixth surface, with the first, second, and third visible light emitting panels respectively corresponding to the fourth, fifth, and sixth surfaces. The color combining prism is used to deflect the light emitted by the first, second, and third visible light emitting panels and allow it to exit from the third surface.

[0009] In some embodiments, the polarization reflection assembly includes a polarization reflector, a phase retardation film, and an infrared reflective film. The polarization reflector includes a first reflecting surface and a second reflecting surface, the first reflecting surface being opposite to a first surface and the second reflecting surface being opposite to a second surface. The polarization reflector transmits first linearly polarized light with a first preset polarization angle and reflects second linearly polarized light with a second preset polarization angle. The phase retardation film and the infrared reflective film are stacked on the surface of the color combining prism opposite to the third surface. The infrared light incident from the first surface is the second linearly polarized light.

[0010] In some embodiments, the first reflective surface of the polarizing reflector is used to reflect infrared light incident from the first surface to the phase retardation film. After the infrared light passes through the phase retardation film, it is reflected by the infrared reflective film and then passes through the phase retardation film and the polarizing reflector in sequence to be directed toward the third surface. The infrared light incident from the third surface is reflected by the polarizing reflector toward the imaging device.

[0011] In some embodiments, the phase delay plate is a 1 / 4 phase delay plate.

[0012] In some embodiments, the display module further includes a collimating lens through which light emitted from the third surface exits.

[0013] In some embodiments, the display module further includes a waveguide device, the waveguide device including a first grating and a second grating, the first grating and the third surface being disposed opposite to each other, and the second grating being opposite to the human eye.

[0014] In some implementations, the area of ​​the first grating is smaller than the area of ​​the second grating.

[0015] In some embodiments, the waveguide device further includes a third grating for deflecting infrared light incident on the first or second grating, so that the infrared light propagates between the first and second gratings.

[0016] In some embodiments, the first grating and the second grating include at least one of a volume holographic grating, a surface relief grating, and a geometric element.

[0017] The head-mounted display of this application includes a first display and a second display; both the first display and the second display include the display module described in any of the above embodiments.

[0018] The head-mounted display and display module for the head-mounted display according to the embodiments of this application deflect the light emitted by the visible light emitting panel using a color-combining prism 13, so that the visible light can be emitted from the third surface 133 to form an image in the human eye. Based on the light source guidance using the color-combining prism, by setting an infrared emitter 11, an imaging device 12 and a polarization reflection component, the infrared light emitted by the infrared emitter 11 can enter from the first surface 131 of the color-combining prism 13, be guided by the polarization reflection component and be emitted from the third surface 133 of the color-combining prism 13. The infrared light reflected by the human eye can also enter from the third surface 133, be guided by the polarization reflection component and be emitted from the second surface 132, and be received by the imaging device 12 to perform eye tracking. Thus, the display module of the extended reality device can both provide a light source and perform eye tracking, realizing the integration of eye tracking and optomechanical display module, greatly reducing the size, volume and weight of the head-mounted display device, and reducing the complexity of the system.

[0019] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein:

[0021] Figure 1 is a schematic diagram of a prior art scenario for some embodiments of this application;

[0022] Figure 2 is a schematic diagram illustrating the application of a head-mounted display according to certain embodiments of this application;

[0023] Figure 3 is a schematic diagram of the structure of a display module according to certain embodiments of this application;

[0024] Figure 4 is a top view of the color-combining prism of a display module according to certain embodiments of this application;

[0025] Figure 5 is a schematic diagram of the structure of the color-combining prism of the display module in some embodiments of this application;

[0026] Figure 6 is a scene diagram of the display module according to some embodiments of this application;

[0027] Figure 7 is a scene diagram of the display module according to some embodiments of this application;

[0028] Figure 8 is a schematic diagram of the waveguide device of a display module according to certain embodiments of this application;

[0029] Figure 9 is a scene diagram of the display module according to some embodiments of this application;

[0030] Figure 10 is a scene diagram of the display module according to some embodiments of this application;

[0031] Figure 11 is a scene diagram of a display module according to some embodiments of this application. Detailed Implementation

[0032] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting the embodiments of this application.

[0033] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one feature. In the description of this application, "multiple" means at least two, such as two or three, unless otherwise explicitly specified.

[0035] 1. Eye tracking: Also known as eyeball tracking, it is based on optical principles to measure the position and movement of the eyeball. Eye tracking is a technology that obtains information by tracking and recording human eye movements. It is a key technology in the field of human-computer interaction. When the eye is illuminated by an infrared light source, the cornea of ​​the eyeball will reflect a bright point. By tracking this reflection point through a high-speed camera, the position and direction of eye movement can be recorded in real time.

[0036] 2. Virtual Reality (VR): Also known as virtual reality or virtual reality technology. Virtual reality technology encompasses computer, electronic information, and simulation technology. Its basic implementation is based on computer technology, utilizing and integrating the latest developments in various high-tech fields such as 3D graphics technology, multimedia technology, simulation technology, display technology, and server technology. The graphics processing unit (GPU) in VR devices processes images of the current scene to create a realistic 3D virtual world with multiple sensory experiences, including visual, tactile, and olfactory sensations, thus giving people in the virtual world a sense of immersion.

[0037] 3. Augmented Reality (AR): Also known as augmented reality, it is a technology that cleverly integrates virtual information with the real world. It widely uses various technologies such as multimedia, 3D modeling, real-time tracking and registration, intelligent interaction, and sensing to simulate and apply computer-generated virtual information such as text, images, 3D models, music, and videos to the real world. The two types of information complement each other, thereby achieving "enhancement" of the real world.

[0038] 4. Mixed Reality (MR): This refers to a new visualization environment created by merging the real and virtual worlds. In this new visualization environment, physical and digital objects coexist and can interact with the real world in real time and obtain information promptly.

[0039] Eye-tracking technology includes invasive and non-invasive tracking, the difference being whether or not it involves direct contact with the human eye. Early eye-tracking technologies typically used invasive methods, such as embedding a scleral search coil into the eye region to track eye movements. This method was highly invasive and significantly disruptive to the user. With advancements in image processing algorithms and computing power, non-invasive eye-tracking has gradually become the mainstream approach.

[0040] Currently, eye movements can be tracked using the iris reflection method. Referring to Figure 1, the iris reflection method can be implemented using a waveguide 100, an infrared light source 101, and two infrared cameras (i.e., infrared cameras 102 and 103 in Figure 1). The infrared light source 101 is generally an infrared LED strip (as shown in Figure 1, it includes multiple infrared LEDs). By attaching the infrared light source 101 to the waveguide 100 and placing infrared cameras 102 and 103 at the bottom of the waveguide 100, the infrared light source 101 provides illumination for the infrared cameras 102 and 103. The infrared cameras 102 and 103 can receive the infrared light reflected from the human eye and can respectively capture images of the left and right sides of the eye to form an image of the human eye, thereby achieving eye tracking.

[0041] While iris reflection can achieve non-invasive eye tracking, infrared cameras typically have a narrow field of view, and eye tracking requires high-precision imaging in close-range scenarios. A single infrared camera may not be able to cover different parts of the iris, meaning it cannot capture a complete reflection image of the eye. Therefore, at least two infrared cameras are required to ensure a complete reflection image is obtained. However, multiple infrared cameras result in a larger display device, higher power consumption, and higher computational resource requirements. Furthermore, to avoid eye obstruction and reduce eye interference, the infrared light source and infrared camera are slightly offset on the optical axis (i.e., off-axis optics), but off-axis optics result in poorer illumination.

[0042] To address the aforementioned technical problems, embodiments of this application provide a head-mounted display and a display module for the head-mounted display.

[0043] To illustrate the various technical solutions in the embodiments of this disclosure more vividly, we will take a head-mounted display as a VR head-mounted display, that is, a display module applied to a VR head-mounted display as an example, as shown in Figure 2. Figure 2 is a schematic diagram of an application scenario of a display module for a head-mounted display provided in the embodiments of this application, which involves a head-mounted display 200.

[0044] Figure 2 illustrates an exemplary head-mounted display 200, but may actually include other numbers of head-mounted displays 200, which is not limited in this application embodiment.

[0045] In one embodiment, the head-mounted display 200 includes a display module 10, a first display 20, a second display 30, and a body 40, wherein the first display 20 and the second display 30 are each provided with at least one display module 10.

[0046] In one embodiment, the display module 10 is disposed at one corner of the first display 20 or the second display 20. The specific placement of the display module 10 can be adaptively adjusted according to the optical path of the display module 10, and this application does not limit this; Figure 2 is merely an example.

[0047] The display module of this application will be described in detail below:

[0048] Please refer to Figures 2 and 3. This application provides a display module 10, which includes an infrared emitter 11, an imaging device 12, a color combining prism 13, a polarization reflection component 14, and at least one visible light emitting panel.

[0049] Infrared transmitter 11 is configured to emit infrared light;

[0050] Imaging device 12 is configured to receive infrared light reflected from the human eye for imaging;

[0051] The color combining prism 13 includes a first surface 131 and a second surface 132, with the first surface 131 and the second surface 132 facing each other. An infrared emitter 11 is disposed opposite to the first surface 131, and an imaging device 12 is disposed opposite to the second surface 132.

[0052] Polarization reflection component 14 is disposed inside the color combining prism 13. The polarization reflection component 14 is used to guide infrared light entering from the first surface 131 to exit from the third surface 133 of the color combining prism 13, and to guide infrared light reflected by the human eye to exit from the second surface 132.

[0053] At least one visible light emitting panel is disposed on a surface other than the first surface 131, the second surface 132 and the third surface 133 of the color combining prism 13. The color combining prism 13 is used to deflect the light emitted by the visible light emitting panel and emit it from the third surface 133 to form an image in the human eye.

[0054] The infrared emitter 11 may include infrared LEDs, etc., and the infrared emitter 11 can emit light in the 850±15 nanometer (nm) band.

[0055] As shown in Figure 3, the imaging device 12 may include an infrared imaging lens 121 and an infrared chip 122. The infrared imaging lens 121 can collect infrared radiation information in the infrared light reflected by the human eye, and the infrared chip 122 can convert the infrared radiation information into an electrical signal. Therefore, the infrared light reflected by the human eye can enter the infrared imaging lens 121 of the imaging device 12 and be imaged on the infrared chip 122, thereby realizing eye tracking.

[0056] Among them, the polarization reflection component can be an optical component that can guide the propagation direction of infrared light.

[0057] The color-combining prism 13 can be an optical element capable of changing the direction of light, merging or separating light rays from different directions. For example, an XCube prism. The color-combining prism 13 can be a rectangle, a cube, etc.

[0058] Optionally, the visible light emitting panel can emit light, for example, polarized light. After being deflected by the color combining prism 13, the light emitted by the visible light emitting panel can exit from the third surface and form an image in the human eye.

[0059] Specifically, referring to Figure 3, the color-combining prism 13 includes a first surface 131 and a second surface 132, with the first surface 131 and the second surface 132 facing each other. An infrared emitter 11 is positioned opposite the first surface 131, and an imaging device 12 is positioned opposite the second surface 132. The optical axes of the infrared emitter 11 and the imaging device 12 are parallel to the third surface 133. Infrared light emitted by the infrared emitter 11 enters the color-combining prism 13 from the first surface 131, is guided by the polarization reflection component, and exits from the third surface 133 to enter the human eye. Infrared light reflected by the human eye enters from the third surface 133, is guided by the polarization reflection component, exits from the second surface 132, and is received by the imaging device 12.

[0060] For example, please refer to Figure 4. The visible light emitting panel includes three panels: a first visible light emitting panel 151, a second visible light emitting panel 152, and a third visible light emitting panel 153. The three visible light emitting panels can emit light of different colors respectively. The color combining prism 13 can deflect the light emitted by the visible light emitting panels. The deflected light can be emitted from the third surface 133 and enter the human eye to achieve imaging in the human eye.

[0061] In this way, by combining the color-combining prism 13 with a visible light emitting panel, which is placed on the surface of the color-combining prism, the visible light emitted by the visible light emitting panel can be deflected by the color-combining prism 13, allowing the visible light to be emitted from the third surface 133 and imaged in the human eye. Based on the light source guidance using the color-combining prism, by setting up an infrared emitter 11, an imaging device 12, and a polarization reflection component, the infrared light emitted by the infrared emitter 11 can enter from the first surface 131 of the color-combining prism 13, be guided by the polarization reflection component, and be emitted from the third surface 133 of the color-combining prism 13. The infrared light reflected by the human eye can also enter from the third surface 133, be guided by the polarization reflection component, be emitted from the second surface 132, and be received by the imaging device 12 for eye tracking. Thus, the display module of the extended reality device can both provide a light source and perform eye tracking, realizing the integration of eye tracking with the optomechanical display module, greatly reducing the size, volume, and weight of the extended display device, and reducing the complexity of the system.

[0062] Optionally, referring to Figures 3 and 4, the visible light emitting panel may include a first visible light emitting panel 151, a second visible light emitting panel 152, and a third visible light emitting panel 153, wherein the first visible light emitting panel 151, the second visible light emitting panel 152, and the third visible light emitting panel 153 are configured to emit light of different wavelengths;

[0063] The color-combining prism 13 also includes a fourth surface 134, a fifth surface 135, and a sixth surface 136. The first visible light emitting panel 151, the second visible light emitting panel 152, and the third visible light emitting panel 153 are respectively arranged in a one-to-one correspondence with the fourth surface 134, the fifth surface 135, and the sixth surface 136. The color-combining prism 13 is used to deflect the light emitted by the first visible light emitting panel 151, the second visible light emitting panel 152, and the third visible light emitting panel 153 and emit it from the third surface 133.

[0064] Optionally, the first visible light emitting panel 151 emits red light, the second visible light emitting panel 152 emits blue light, and the third visible light emitting panel 153 emits green light.

[0065] Among them, the wavelength of red light can be 630±16nm, the wavelength of blue light can be 463±9nm, and the wavelength of green light can be 538±17nm.

[0066] Optionally, the color-combining prism 13 also includes a red light reflective film 1341 and a blue light reflective film 1351. The red light reflective film 1341 can reflect red light and transmit light of other wavelengths, while the blue light reflective film 1351 can reflect blue light and transmit light of other wavelengths.

[0067] Specifically, the color-combining prism 13 is a rectangular body with six surfaces, namely a first surface 131, a second surface 132, a third surface 133, a fourth surface 134, a fifth surface 135, and a sixth surface 136. The infrared emitter 11 is positioned relative to the first surface 131, the imaging device 12 is positioned relative to the second surface 132, the first visible light emitting panel 151 is positioned corresponding to the fourth surface 134, the second visible light emitting panel 152 is positioned corresponding to the fifth surface 135, and the third visible light emitting panel 153 is positioned corresponding to the sixth surface 136.

[0068] Please refer to Figure 5. The first surface 131 is ABCD, the second surface 132 is abcd, the third surface 133 is AaBb, the fourth surface 134 is BbCc, the fifth surface 135 is AaDd, and the sixth surface 136 is CcDd. The first visible light emitting panel 151 is positioned relative to the BbCc surface, the second visible light emitting panel 152 is positioned relative to the AaDd surface, and the third visible light emitting panel 153 is positioned relative to the CcDd surface.

[0069] Because a red light reflector 1341 and a blue light reflector 1351 are provided in the color-combining prism 13, the red light emitted by the first visible light emitting panel 151 is reflected onto the third surface 133 after propagating to the red light reflector 1341, and the blue light emitted by the second visible light emitting panel 152 is reflected onto the third surface 133 after propagating to the blue light reflector 1351. The green light emitted by the third visible light emitting panel 153 is not reflected by the red light reflector 1341 and the blue light reflector 1351, and can be directly incident on the third surface 133. The red, blue, and green light beams are combined and emitted from the third surface 133, enabling the color-combining prism 13 to achieve a color optical engine function. By integrating the polarization reflection component into the color-combining prism 13, the color-combining prism 13 can perform eye tracking while achieving a color optical engine function, greatly reducing the device size, volume, and weight of the head-mounted display.

[0070] Referring to Figure 3, in some embodiments, the polarization reflection assembly includes a polarization reflector 141, a phase retardation film 142, and an infrared reflective film 143. The polarization reflector 141 includes a first reflective surface 1411 and a second reflective surface 1412. The first reflective surface 1411 is opposite to the first surface 131, and the second reflective surface 1412 is opposite to the second surface 132. The polarization reflector 141 transmits first linearly polarized light with a first preset polarization angle and reflects second linearly polarized light with a second preset polarization angle. The phase retardation film 142 and the infrared reflective film 143 are stacked on the surface of the color combining prism 13 opposite to the third surface 133. The infrared light incident from the first surface 131 is second linearly polarized light.

[0071] Optionally, the first surface 131 of the polarizing reflector 141 is used to reflect infrared light incident from the first surface 131 to the phase retarder 142. After the infrared light passes through the phase retarder 142, it is reflected by the infrared reflective film 143 and then passes through the phase retarder 142 and the polarizing reflector 141 in sequence to be incident on the third surface 133. The infrared light incident from the third surface 133 is reflected by the polarizing reflector 141 to the imaging device 12.

[0072] The polarizing reflector 141 may be an infrared polarizing reflective film 141. The infrared polarizing reflective film 141 includes a first reflective surface 1411 and a second reflective surface 1412, wherein the first reflective surface 1411 is opposite to the first surface 131, and the second reflective surface 1412 is opposite to the second surface 132.

[0073] The phase retardation plate 142 and the infrared reflective film 143 are stacked on the surface (sixth surface 136) opposite to the third surface 133 in the color combining prism 13. The phase retardation plate 142 is located between the polarizer 141 and the infrared reflective film 143. The phase retardation plate 142 can switch linearly polarized light to rotated polarized light and switch rotated polarized light to linearly polarized light. The phase retardation plate 142 includes a 1 / 4 phase retardation plate (Quarter-Wave Plate, QWP).

[0074] The first linearly polarized light with a first preset polarization angle can be P-polarized light, and the second linearly polarized light with a second preset polarization angle can be S-polarized light. The first and second linearly polarized light can switch after passing through two phase retardation plates 142. For example, the first linearly polarized light can switch to the second linearly polarized light after being modulated by two phase retardation plates 142. The polarizing reflector 141 can transmit P-polarized light and reflect S-polarized light.

[0075] When the light reflected by the human eye (including P-polarized light and S-polarized light) passes through the second reflecting surface 1412, the P-polarized light reflected by the human eye is transmitted, while the S-polarized light is reflected to the imaging device 12. The imaging device 12 performs eye tracking based on the S-polarized light reflected by the human eye.

[0076] It should be noted that although the P-polarized light reflected by the human eye can be transmitted through the second reflecting surface 1412 into the color combining prism 13 and propagate inside the color combining prism 13, its propagation does not affect the deflection of the light emitted by the visible light emitting panel by the color combining prism 13, that is, it does not affect the imaging display of the color combining prism 13.

[0077] Specifically, for example, a polarizing film can be provided between the infrared emitter 11 and the first surface 131 to ensure that all infrared light entering from the first surface 131 is S-polarized light. Referring to the figure, taking the polarizing reflector 141 as an infrared polarizing reflective film 141 as an example, the infrared light emitted by the infrared emitter 11 enters from the first surface 131, is reflected by the first reflecting surface 1411 to the quarter-phase retarder 142, and after passing through the quarter-phase retarder 142 (at this time, the S-polarized light becomes circularly polarized light), it is reflected again by the infrared reflective film 143 to the quarter-phase retarder 142. The infrared light emitted from the quarter-phase retarder 142 is converted into P-polarized light, and passes through the infrared polarizing reflective film 141 in sequence, from the second reflecting surface 1412 of the infrared polarizing reflective film 141 to the third surface 133, and then exits from the third surface 133. The S-polarized light in the infrared light reflected back by the human eye can enter from the third surface 133, propagate to the infrared polarization reflective film 141, and then propagate to the imaging device 12 through the reflection of the infrared polarization reflective film 141, so as to realize eye tracking.

[0078] Please refer to Figures 3 and 6. In some embodiments, the display module 10 also includes a waveguide device 16.

[0079] The waveguide device 16 includes a first grating 1611 and a second grating 162. The first grating 161 and the third surface 133 are arranged opposite to each other, and the second grating 162 is opposite to the human eye.

[0080] Optionally, the area of ​​the first grating 161 is smaller than the area of ​​the second grating 162.

[0081] Infrared light emitted from the third surface 133 of the color-combining prism 13 enters through the first grating 161 and exits through the second grating 162. Infrared light reflected by the human eye enters through the second grating 162 and exits through the first grating 161. Infrared light emitted from the first grating 161 enters through the third surface 133 and exits through the second surface 132, so as to be received by the imaging device 12.

[0082] Optionally, the display module 10 also includes a collimating lens 17, through which light emitted from the third surface 133 exits.

[0083] The collimating lens 17 is disposed between the first grating 161 and the third surface 133. The collimating lens 17 allows infrared light to enter the first grating 161 perpendicularly.

[0084] Specifically, waveguides are widely applicable in eye tracking due to their ability to effectively transmit light without excessive scattering or energy loss. Referring to Figures 3 and 5, the waveguide device 16 may include a first grating 161 and a second grating 162. The first grating 161 and the third surface 133 are positioned opposite each other, while the second grating 162 faces the human eye. Therefore, the first grating 161 can receive infrared light emitted from the third surface 133 and can also direct infrared light reflected from the human eye towards the third surface 133. That is, the infrared light emitted by the infrared emitter 11, after being guided by the polarization and reflection component, can exit from the third surface 133, enter the first grating 161, and then be directed towards the human eye via the second grating 162. The second grating 162 can also receive infrared light reflected from the human eye and propagate it back to the first grating 161, so that the infrared light reflected from the human eye enters from the third surface 133. In other words, the infrared light emitted by the infrared emitter 11 can enter through the first grating 161, be conducted in the waveguide device 16, and then exit through the second grating 162. The infrared light can be evenly irradiated onto the human eye, avoiding the omission of eye movement information. The infrared light reflected by the human eye can enter through the second grating 162, be conducted in the waveguide device 16, and then exit through the first grating 161, and then be received by the imaging device 12.

[0085] Please refer to Figure 7. In order for the first grating 161 and the second grating 162 to propagate infrared light, the periodic distribution inside the grating can be as shown in Figure 7. By controlling the periodic distribution inside the grating, infrared light can also propagate within the waveguide device 16.

[0086] Since the area of ​​the first grating 161 is smaller than that of the second grating 162, the relatively smaller area of ​​the first grating 161 allows the infrared light emitted from the third surface 133 to enter the waveguide device 16 more concentratedly and as much as possible. When the second grating 162 receives the infrared light emitted by the human eye, it also ensures that the imaging device 12 can fully receive the infrared light reflected back from the waveguide device 16, thereby ensuring the effect of eye tracking. The relatively larger area of ​​the second grating 162 can increase the coverage of the infrared light emitted from the third surface 133, allowing the infrared light to cover the human eye and the area around the human eye. Even when the position of the human eye changes slightly, the infrared light can still illuminate the cornea, thereby increasing the fault tolerance range of the display module 10. Furthermore, when receiving the infrared light reflected from the human eye, it can obtain the complete reflected light of the human iris, thereby ensuring that the imaging device 12 can obtain a complete image of the human iris, thus ensuring the effect of eye tracking.

[0087] Thus, by setting up the waveguide device 16, the infrared light emitted by the infrared emitter 11, guided by the polarization reflection component, can exit from the third surface 133 and enter the first grating 161 of the waveguide device 16. This allows the infrared light to enter the waveguide device 16 in a more concentrated and abundant manner, exiting from the second grating 162 and entering the human eye. The infrared light reflected from the human eye can enter the waveguide device 16 from the second grating 162, exit from the first grating 161, enter the third surface 133, and, guided by the polarization reflection component, finally propagate to the imaging device 12 for imaging. The imaging device 12 can fully receive the infrared light reflected back from the human eye for eye tracking. Based on the thin and light characteristics of the waveguide device 16, integrating the function of emitting infrared light and capturing human eye images for eye tracking into a single display module 10 can greatly reduce the hardware structure required for eye tracking in head-mounted displays and lower system complexity.

[0088] Since the waveguide device 16 includes a first grating 161 and a second grating 162, and the area of ​​the first grating 161 is smaller than the area of ​​the second grating 162, it can not only improve the coverage of the infrared light emitted by the infrared emitter 11 to the human eye, but also ensure that when receiving the infrared light reflected from the human eye, the complete reflected light from the iris is obtained, allowing the imaging device 12 to acquire a complete image of the iris, thereby improving the eye-tracking effect. Furthermore, during eye-tracking, multiple infrared cameras are not required; only one imaging device 12 is needed to complete the imaging, further reducing the size of the display module 10.

[0089] Optionally, the waveguide device 16 further includes a third grating 163, which is used to deflect the infrared light incident on the first grating 161 or the second grating 162 so that the infrared light propagates between the first grating 161 and the second grating 162.

[0090] Specifically, referring to Figure 8, the waveguide device 16 also includes a third grating 163. The third grating 163 can be disposed below the first grating 161 (in the horizontal direction) and to the left of the second grating 162. The infrared light emitted by the infrared emitter 11 enters the waveguide device 16 from the first grating 161 and propagates to the third grating 163. The third grating 163 deflects the light, causing the light to propagate to the second grating 162 and then to the human eye. The infrared light reflected by the human eye enters the waveguide device 16 from the second grating 162 and propagates to the third grating 163. The third grating 163 also deflects the light, causing the light to propagate to the first grating 161 and then to the imaging device 12. In this way, by setting the third grating 163, the propagation of infrared light between the first grating 161 and the second grating 162 can be controlled.

[0091] It is understandable that the actual position of the third grating 163 can be adaptively adjusted according to the actual positions of the first grating 161 and the second grating 162 and the direction of light propagation, so as to realize the propagation of infrared light between the first grating 161 and the second grating 162.

[0092] Please refer to Figure 9. Based on the multiplexing of the first grating 161, the second grating 162 and the third grating 163 of the waveguide device 16, both the infrared light emitted by the infrared emitter 11 and the infrared light reflected by the human eye can propagate to achieve eye tracking. The diffraction efficiency of the infrared light is shown in Figure 9.

[0093] Infrared light emitted by infrared emitter 11 propagates from the first surface 131 into the color combining prism 13, propagates to the first reflecting surface 1411 of infrared polarization reflective film 141, and then strikes the sixth surface 136. After reflection and polarization by the 1 / 4 phase retardation plate 142 and infrared reflective film 143, it passes through the first reflecting surface 1411 again, exits from the second reflecting surface 1412 of infrared polarization reflective film 141, strikes the third surface 133, and enters the first grating 161 after passing through collimating lens 17. Infrared light reflected by the human eye exits from the first grating 161, passes through collimating lens 17, enters the color combining prism 13 from the third surface 133, propagates to the second reflecting surface 1412 of infrared polarization reflective film 141, is reflected to the second surface 132, and exits from the second surface 132 to the imaging device 12 for eye tracking.

[0094] In this way, the display module 10 is integrated into the color combining prism 13, which can realize the color optical engine function, which can further reduce the size of the head-mounted display 100, provide leeway for the structural space of the head-mounted display 100, effectively reduce the structural design difficulty of the head-mounted display 100, ensure the performance optimization freedom of the head-mounted display 100, and improve the performance of the device.

[0095] In some embodiments, the first grating 161 and the second grating 162 include at least one of a volume holographic grating, a surface relief grating, and a geometric element.

[0096] Among them, the geometric device can be an arrayed waveguide grating.

[0097] Specifically, when the first grating 161 and the second grating 162 include volume holographic gratings, the light path propagation is as shown in Figure 3, which will not be repeated here. When the first grating 161 and the second grating 162 include surface relief gratings, please refer to Figure 10. In this case, the first grating 161 includes a first coupling grating 1611, a second coupling grating 1612, and a third coupling grating 1613, and the second grating 162 includes a first coupling grating 1621, a second coupling grating 1622, and a third coupling grating 1623. Blue and green light can be coupled into the first coupling grating 1611 and coupled out through the first coupling grating 1621. Red and green light can be coupled into the second coupling grating 1612 and coupled out through the second coupling grating 1622. Infrared light can be coupled into the third coupling grating 1613 and coupled out through the third coupling grating 1623. The light path propagation path and propagation principle are similar to those described above, and will not be repeated here. When the first grating 161 and the second grating 162 include arrayed waveguide gratings, please refer to Figure 11. The optical path propagation path and propagation principle are similar to those described above and will not be repeated here.

[0098] In the description of this specification, the references to terms such as "some embodiments," "in one example," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0099] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.

[0100] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A display module for a head-mounted display, wherein, include: Infrared transmitter, configured to emit infrared light; An imaging device configured to receive infrared light reflected from the human eye for imaging; A color-combining prism, comprising a first surface and a second surface, the first surface and the second surface being opposite to each other, an infrared emitter being disposed opposite to the first surface, and an imaging device being disposed opposite to the second surface; A polarization reflection component is disposed within the color combining prism. The polarization reflection component is used to guide infrared light incident from the first surface to exit from the third surface of the color combining prism, and to guide infrared light reflected from the human eye to exit from the second surface. At least one visible light emitting panel is disposed on a surface other than the first, second, and third surfaces of the color combining prism. The color combining prism is used to deflect the light emitted by the visible light emitting panel and emit it from the third surface to form an image in the human eye.

2. The display module for a head-mounted display according to claim 1, wherein, The visible light emitting panel includes a first visible light emitting panel, a second visible light emitting panel, and a third visible light emitting panel, wherein the first visible light emitting panel, the second visible light emitting panel, and the third visible light emitting panel are configured to emit light of different wavelengths; The color-combining prism further includes a fourth surface, a fifth surface, and a sixth surface. The first visible light emitting panel, the second visible light emitting panel, and the third visible light emitting panel are respectively arranged in a one-to-one correspondence with the fourth surface, the fifth surface, and the sixth surface. The color-combining prism is used to deflect the light emitted by the first visible light emitting panel, the second visible light emitting panel, and the third visible light emitting panel, and to emit it from the third surface.

3. The display module for a head-mounted display according to claim 1 or 2, wherein, The polarization reflection assembly includes a polarization reflector, a phase retarder, and an infrared reflective film. The polarization reflector includes a first reflective surface and a second reflective surface. The first reflective surface is opposite to the first surface, and the second reflective surface is opposite to the second surface. The polarization reflector transmits first linearly polarized light with a first preset polarization angle and reflects second linearly polarized light with a second preset polarization angle. The phase retarder and the infrared reflective film are stacked on the surface of the color combining prism opposite to the third surface. The infrared light incident from the first surface is the second linearly polarized light.

4. The display module for a head-mounted display according to claim 3, wherein, The first reflective surface of the polarizing reflector is used to reflect infrared light incident from the first surface to the phase retarder. After the infrared light passes through the phase retarder and is reflected by the infrared reflective film, it passes through the phase retarder and the polarizing reflector in sequence to be directed toward the third surface. Infrared light incident from the third surface is reflected by the polarizing reflector toward the imaging device.

5. The display module for a head-mounted display according to claim 3 or 4, wherein, The phase delay plate is a 1 / 4 phase delay plate.

6. The display module for a head-mounted display according to any one of claims 1-5, wherein, The display module also includes a collimating lens, through which light emitted from the third surface exits.

7. The display module for a head-mounted display according to claim 1, wherein, The display module also includes: A waveguide device, comprising a first grating and a second grating, wherein the first grating and the third surface are disposed opposite to each other, and the second grating is opposite to the human eye.

8. The display module for a head-mounted display according to claim 7, wherein, The area of ​​the first grating is smaller than the area of ​​the second grating.

9. The display module for a head-mounted display according to claim 7, wherein, The waveguide device further includes a third grating, which is used to deflect the infrared light incident on the first grating or the second grating so that the infrared light propagates between the first grating and the second grating.

10. The display module for a head-mounted display according to any one of claims 7-9, wherein, The first and second gratings include at least one of the following: volume holographic grating, surface relief grating, and geometric components.

11. A head-mounted display, wherein, include: A first display and a second display; both the first display and the second display include the display module for a head-mounted display as described in any one of claims 1 to 10.

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