A near-eye optical display system

Abstract

The application provides a near-eye optical display system, which comprises a first optical assembly, a second optical assembly and an eyeball tracking module; the first optical assembly receives image light from an image source and forms a folded light path to guide the image light to a human eye direction; the first optical assembly comprises a first lens, a light splitting element arranged on the image source side of the first lens, a phase retarder arranged on the human eye side of the first lens and a polarization reflection element; the second optical assembly is located between the first optical assembly and the human eye, and comprises a second lens; the second lens has a third surface facing the first optical assembly and a fourth surface facing the human eye; the eyeball tracking module comprises a camera; the camera is arranged on the third surface side and located in a peripheral area of the second lens which does not participate in virtual imaging of the folded light path; the third surface is a convex surface in the area corresponding to the camera; and the imaging light path of the camera is the eye movement image information of the human eye after being refracted by the second lens and reaching the camera.

Description

Technical Field

[0001] This application relates to the field of optical display technology, and more specifically, to a near-eye optical display system. Background Technology

[0002] With the rapid development of virtual reality technology, lightweight, compact VR optical display systems with eye-tracking capabilities have become an industry trend. Adding an eye-tracking module to a VR optical display system typically increases the overall system size.

[0003] In conventional pancake folded optical path solutions, the eye-tracking light source and camera are typically positioned near the screen. However, limited by the inherent light efficiency of the pancake solution (theoretically around 25%), the infrared light path needs to penetrate the low-efficiency folded optical path twice, resulting in low light energy utilization. Therefore, how to provide a reasonable placement for the eye-tracking module to improve the light energy utilization of eye tracking while maintaining system compactness is a pressing technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this application is to provide a new technical solution for a near-eye optical display system.

[0005] This application provides a near-eye optical display system, including: A first optical component is configured to receive image light from an image source and form a folded optical path to guide the image light toward the human eye. The first optical component includes a first lens, a beam splitter disposed on the image source side of the first lens, a phase delayer disposed on the human eye side of the first lens, and a polarization reflection element. A second optical component, located between the first optical component and the human eye, includes a second lens having a third surface facing the first optical component and a fourth surface facing the human eye; and... An eye-tracking module includes at least one camera, which is disposed on the third surface side and located in the peripheral area of ​​the second lens that does not participate in the virtual imaging of the folded optical path, wherein the third surface is convex in the area corresponding to the camera; In this system, the imaging optical path of the camera is such that the eye movement image information of the human eye is refracted by the second lens and then reaches the camera.

[0006] Optionally, the second lens satisfies: 5% < (D2 - D1) / D1 < 22%, where D1 is half the aperture of the optically effective region on the second lens that participates in the virtual imaging of the folded optical path, D2 is half the aperture of the second lens, and the peripheral region is the region on the second lens from the edge of the optically effective region to the edge of the second lens.

[0007] Optionally, the near-eye optical display system satisfies: 0.7 < D2 / D3 < 0.9, where D2 is half the aperture of the second lens, D3 is half the aperture of the first lens, and the aperture of the first lens is larger than the aperture of any other lens in the near-eye optical display system.

[0008] Optionally, the fourth surface of the second lens in the area corresponding to the camera is any one of a convex surface, a concave surface, and a plane.

[0009] Optionally, the first optical component further includes a third lens, which is located between the first lens and the second lens; The optical power of the first lens, the second lens, and the third lens is all positive.

[0010] Optionally, the optical display system further includes a display screen, the light-emitting surface of which is provided with protective glass, and the display screen is located on the image source side for emitting image light; On the optical axis, the distance from the fourth surface of the second lens closest to the human eye to the second surface of the first lens closest to the human eye is T5, and the distance from the fourth surface of the second lens to the display screen is T6, and T5 and T6 satisfy: 0.35 < T5 / T6 < 0.83.

[0011] Optionally, the beam-splitting element is disposed on the first surface of the first lens facing the image source side; The phase delayer and the polarization reflection element are stacked to form a composite film layer, which is disposed on the second surface of the first lens facing the human eye or on the surface of the third lens facing the human eye. The phase delayer is located between the beam splitter and the polarization reflector.

[0012] Optionally, the near-eye optical display system further includes a polarization element disposed on the side surface of the polarization reflective element opposite to the phase retarder.

[0013] Optionally, the total optical length (TTL) of the near-eye optical display system satisfies: 16mm < TTL < 25mm.

[0014] Optionally, the half-aperture D3 of the first lens satisfies: 17mm < D3 < 22mm.

[0015] One technical advantage of this application is: The near-eye optical display system provided in this application provides an eye-tracking module camera positioned on the image source side of the second lens, within the peripheral region of the second lens where it does not participate in the virtual imaging of the folded optical path. This ensures that the camera's imaging optical path does not pass through the low-efficiency folded optical path in the first optical component. Instead, the camera's imaging optical path uses eye-tracking image information refracted by the second lens to reach the camera. This effectively avoids light energy loss caused by the infrared optical path penetrating the low-efficiency film layer twice, significantly improving the light energy utilization rate of eye tracking. Simultaneously, since the camera is arranged within the peripheral region of the second lens, it does not increase the system's effective optical aperture. While achieving the aforementioned optical path optimization, the system maintains its compactness, balancing the needs of miniaturization and high-precision eye tracking. This solves the technical problem of low light energy utilization and difficulty in balancing system size in existing eye tracking technologies.

[0016] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0018] Figure 1 The optical structure and optical path diagram of the near-eye optical display system provided in Embodiment 1 of this application; Figure 2 A schematic diagram of the composite film layer disposed on the lens provided in the embodiments of this application; Figure 3 A schematic diagram of an optical structure for a near-eye optical display system provided in an embodiment of this application; Figure 4 for Figure 1 The dot matrix diagram of the near-eye optical display system is shown below. Figure 5 for Figure 1 The modulation transfer function (MTF) curve of the near-eye optical display system is shown. Figure 6 for Figure 1 Field curvature and distortion diagram of the near-eye optical display system shown; Figure 7 for Figure 1 The transverse chromatic aberration diagram of the near-eye optical display system shown; Figure 8 The optical structure and optical path diagram of the near-eye optical display system provided in Embodiment 2 of this application; Figure 9 for Figure 8 The dot matrix diagram of the near-eye optical display system is shown below. Figure 10 for Figure 8 The modulation transfer function (MTF) curve of the near-eye optical display system is shown. Figure 11 for Figure 8 Field curvature and distortion diagram of the near-eye optical display system shown; Figure 12 for Figure 8 The transverse chromatic aberration diagram of the near-eye optical display system shown; Figure 13 The optical structure and optical path diagram of the near-eye optical display system provided in Embodiment 3 of this application; Figure 14 for Figure 13 The dot matrix diagram of the near-eye optical display system is shown below. Figure 15 for Figure 13 The modulation transfer function (MTF) curve of the near-eye optical display system is shown. Figure 16 for Figure 13 Field curvature and distortion diagram of the near-eye optical display system shown; Figure 17 for Figure 13 The transverse chromatic aberration diagram of the near-eye optical display system shown; Figure 18 The optical structure and optical path diagram of the near-eye optical display system provided in Embodiment 4 of this application; Figure 19 for Figure 18 The dot matrix diagram of the near-eye optical display system is shown below. Figure 20 for Figure 18 The modulation transfer function (MTF) curve of the near-eye optical display system is shown. Figure 21 for Figure 18 Field curvature and distortion diagram of the near-eye optical display system shown; Figure 22 for Figure 18 The diagram shows the chromatic aberration of the near-eye optical display system.

[0019] Explanation of reference numerals in the attached figures: 1. Display screen; 2. Protect the glass; 3. First lens; 31. First surface; 32. Second surface; 4. Second lens; 41. Third surface; 42. Fourth surface; A. Peripheral region; 5. Third lens; 51. Fifth surface; 52. Sixth surface; 6. Camera; 7. Spectroscopic element; 8. Phase delay unit; 9. Polarizing reflective element; 10. Polarizing elements; 11. Anti-reflective film; 01. The human eye. Detailed Implementation

[0020] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0021] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0022] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0023] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0025] The near-eye optical display system provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0026] According to one aspect of this application, a near-eye optical display system is provided, see [link to relevant documentation]. Figures 1 to 3The near-eye optical display system includes a first optical component, a second optical component, and an eye-tracking module. The first optical component is configured to receive image light from an image source and form a folded optical path to guide the image light towards the human eye. The first optical component includes a first lens 3, a beam splitter 7 disposed on the image source side of the first lens 3, a phase delayer 8 disposed on the human eye side of the first lens 3, and a polarization reflection element 9. The second optical component is located between the first optical component and the human eye 01. The second optical component includes a second lens 4, which has a third surface 41 facing the first optical component and a fourth surface 42 facing the human eye 01. The eye-tracking module includes at least one camera 6, which is disposed on the third surface 41 side and located in the peripheral region A of the second lens 4 that does not participate in the virtual imaging of the folded optical path. The third surface 41 is convex in the region corresponding to the camera 6. The imaging optical path of the camera 6 is the eye movement image information of the human eye refracted by the second lens 4 before reaching the camera 6.

[0027] This application provides a near-eye optical display system that can be applied to virtual reality (VR) display devices. See also... Figures 1 to 3 The near-eye optical display system includes a first optical component, a second optical component, and an eye-tracking module. The components of the near-eye optical display system provided in this application are described in detail below.

[0028] The first optical component is configured to receive image light from an image source (e.g., a display screen) and form a folded optical path, and to guide the image light toward the human eye in the O1 direction. Specifically, see [link to relevant documentation]. Figure 1 The first optical component includes a first lens 3, a beam splitter 7 disposed on the image source side of the first lens 3, a phase delayer 8 disposed on the human eye side of the first lens 3, and a polarization reflection element 9.

[0029] The beam splitting element 7 is a semi-transparent and semi-reflective film, which is disposed on the image source side of the first lens 3 and is used to split the incident light: part of the light is reflected and the other part is transmitted.

[0030] The phase delayer 8 is a quarter-wave plate, which is set on the human eye side of the first lens 3 to change the polarization state of light, specifically to convert linearly polarized light into circularly polarized light, or to convert circularly polarized light into linearly polarized light.

[0031] The polarization reflection element 9 is a polarization reflection film disposed on the side of the phase retarder 8 opposite to the first lens 3, used to reflect light of the first polarization state and transmit light of the second polarization state orthogonal to the first polarization state. The polarization reflection element 9 and the phase retarder 8 are, for example, stacked together.

[0032] See Figure 1 The beam splitter 7, the phase retarder 8, and the polarization reflection element 9 work together to cause the image light to undergo multiple reflections and transmissions on both sides of the first lens 3: the image light from the image source is sequentially transmitted through the beam splitter 7, its polarization state is converted by the phase retarder 8, reflected by the polarization reflection element 9, then its polarization state is converted again by the phase retarder 8, subsequently reflected by the beam splitter 7, and then its polarization state is converted again by the phase retarder 8 and transmitted through the polarization reflection element 9, thereby achieving optical path folding. Through this optical path folding design, the overall optical length of the near-eye optical display system is effectively compressed, allowing it to maintain good optical performance while having a thinner system thickness.

[0033] See Figure 1 The second optical component is located between the first optical component and the human eye 01, that is, the second optical component is located on the side closer to the human eye 01. The second optical component includes a second lens 4, which has a third surface 41 facing the first optical component and a fourth surface 42 facing the human eye 01. Anti-reflective coatings may be provided on both surfaces of the second lens 4. The second lens 4 is used to transmit the image light modulated by the first optical component to the human eye 01 and to further correct system aberrations to ensure image quality.

[0034] The eye-tracking module includes at least one camera 6. The camera 6 is disposed on the third surface 41 and located within the peripheral region A of the second lens 4, see [link / reference needed]. Figure 2 The peripheral region A does not participate in the virtual imaging of the folded optical path. The third surface 41 is convex in the region corresponding to the camera 6. The imaging optical path (infrared light) sequence of the camera 6 is as follows: after the human eye is irradiated by infrared light, the infrared light is reflected or scattered from the surface of the eyeball (cornea, iris, pupil) and enters the camera 6. The advantage of this configuration is that the imaging optical path of the camera 6 does not need to pass through the folded optical path with low light efficiency in the first optical component, thereby avoiding the light energy loss caused by the infrared light penetrating the low light efficiency film layer twice, and significantly improving the light energy utilization rate of eye tracking; in addition, since the camera 6 is arranged in the peripheral region A of the second lens 4, it does not occupy the effective optical aperture of the system, thus maintaining the compactness of the system while improving the eye tracking performance.

[0035] Therefore, this application maintains the system's compactness while achieving the aforementioned optical path optimization, taking into account both miniaturization and high-precision eye tracking requirements, and solving the technical problems of low light energy utilization and difficulty in balancing system size in existing eye tracking technologies.

[0036] See some examples in this application. Figure 3 The second lens 4 satisfies: 5% < (D2 - D1) / D1 < 22%, where D1 is half the aperture of the optically effective region on the second lens 4 that participates in the virtual imaging of the folded optical path, D2 is half the aperture of the second lens 4, and the peripheral region A is the region on the second lens 4 from the edge of the optically effective region to the edge of the second lens 4.

[0037] See Figure 3 The second lens 4 satisfies the relationship: 5% < (D2 - D1) / D1 < 22%. Here, D1 is half the aperture of the effective optical region on the second lens 4 that participates in the virtual imaging of the folded optical path, i.e., the radial dimension of the second lens 4 that actually participates in visible light imaging, and its boundary is determined by the effective aperture during system design. D2 is half the aperture of the second lens 4, i.e., the physical radius of the second lens 4, which is the radial distance from the optical axis center of the second lens 4 to the lens edge, representing the actual physical size of the second lens 4. The peripheral region A is the area on the second lens 4 from the edge of the effective optical region to the edge of the second lens 4, i.e., the annular region between D1 and D2, which does not participate in the virtual imaging of the folded optical path.

[0038] This application, by limiting (D2-D1) / D1 within the aforementioned range, ensures that the peripheral region A has sufficient radial width, providing ample space for the camera 6 to be reliably positioned on the third surface 41. Furthermore, it avoids the physical half-aperture D2 of the second lens 4 being excessively large relative to the optically effective area half-aperture D1, thus preventing an unnecessary increase in the overall system size. If (D2-D1) / D1 is less than 5%, the peripheral region A is too narrow, resulting in insufficient space for the camera 6 and potentially affecting the installation accuracy and flexibility of the eye-tracking module. Conversely, if (D2-D1) / D1 is greater than 22%, the physical size of the second lens 4 is too large relative to the optically effective area, leading to an increase in the overall system size and hindering device miniaturization. Therefore, limiting this ratio to between 5% and 22% ensures both camera placement flexibility and system compactness, facilitating the realization of a miniaturized near-eye optical display system.

[0039] It should be noted that the number of cameras 6 can be configured according to actual tracking needs. Specifically, one camera 6 can be set, and its position can be referenced. Figure 1 As shown, the camera 6 is located in the peripheral region A on the third surface 41 side of the second lens 4. Of course, two cameras 6 can also be configured, with the two cameras positioned opposite each other on the third surface 41 side of the second lens 4, for example... Figure 1 Another camera is added at the relative position of the shown camera 6 to improve the coverage and accuracy of eye tracking.

[0040] Furthermore, the eye-tracking module described in this application also includes multiple infrared light sources for emitting infrared light to illuminate the human eye and assist the camera 6 in image acquisition. The infrared light sources can be positioned around the image source, for example, one or more infrared LEDs can be arranged around the display screen 1; their specific number and position can be determined according to system design requirements.

[0041] In some examples of this application, the near-eye optical display system satisfies: 0.7 < D2 / D3 < 0.9, where D2 is half the aperture of the second lens 4, D3 is half the aperture of the first lens 3, and the aperture of the first lens 3 is larger than the aperture of any other lens in the near-eye optical display system.

[0042] The near-eye optical display system of this application satisfies the relationship: 0.7 < D2 / D3 < 0.9, where D2 is the half-aperture of the second lens 4, i.e., the physical radius of the second lens 4; D3 is the maximum half-aperture of the near-eye optical display system, i.e., the half-aperture of the first lens 3 located on the image source side, which is the maximum value of the physical half-apertures of all lenses in the entire system. In the optical design, D3 is located on the first lens 3 near the image source side in the first optical component because the lens at this position needs to receive a larger aperture beam, and its physical aperture is often larger than that of other lenses in the system.

[0043] By controlling the D2 / D3 ratio between 0.7 and 0.9, it indicates that the physical half-aperture D2 of the second lens 4 is smaller than but close to the maximum half-aperture D3 of the entire system (i.e., the half-aperture of the first lens 3). In other words, although the peripheral region A of the second lens 4 extends radially relative to its optically effective area, this extension does not cause the physical aperture of the second lens 4 to exceed the maximum aperture D3 of the system. Therefore, the increased radial dimension of the camera 6 in the eye-tracking module, arranged using the peripheral region A, does not lead to an increase in the maximum aperture of the entire optical system, thus maintaining a compact overall system size.

[0044] If the ratio of D2 / D3 is less than or equal to 0.7, the physical half-aperture of the second lens 4 is too small relative to the maximum half-aperture of the system, and the radial width of the outer region A is insufficient, making it difficult to provide enough space for the camera 6. If the ratio of D2 / D3 is greater than or equal to 0.9, the physical half-aperture of the second lens 4 is too close to or even exceeds the maximum half-aperture of the system, which can easily lead to an increase in the maximum aperture of the system, thus making it difficult to maintain the compactness of the system. Controlling the ratio of D2 / D3 between 0.7 and 0.9 can effectively avoid increasing the overall size of the system while providing sufficient space for the camera 6.

[0045] In some examples of this application, the fourth surface 42 of the second lens 4 is any one of a convex surface, a concave surface, and a plane in the area corresponding to the camera 6.

[0046] The fourth surface 42 of the second lens 4 is convex, concave, or planar in the region corresponding to the camera 6. That is, the fourth surface 42 in the local region corresponding to the camera 6 can be selected with different surface shapes according to design requirements. Specifically, this region can be designed as a convex surface to converge the imaging beam of the camera 6; it can also be designed as a concave surface to diverge the imaging beam of the camera 6; or it can be designed as a planar surface to minimize the deflection effect on the imaging beam.

[0047] The selection of the surface shape of the fourth surface 42 in the corresponding area of ​​the camera 6 depends on the optical path design and aberration correction requirements of the eye-tracking module. Since the imaging optical path of the camera 6 needs to be transmitted through the fourth surface 42 to reach the human eye 01, the local surface shape of this surface affects the field of view, imaging sharpness, and the quality of the acquired human eye image of the camera 6. Therefore, by flexibly configuring the surface shape of this area, the imaging optical path of the camera 6 can be optimized, improving the accuracy and reliability of eye tracking.

[0048] See some examples in this application. Figure 8 and Figure 13 The first optical component further includes a third lens 5, which is located between the first lens 3 and the second lens 4; the optical power of the first lens 3, the second lens 4 and the third lens 5 are all positive.

[0049] See Figure 8 and Figure 13 By adding a third lens 5 between the first lens 3 and the second lens 4, and configuring all three lenses to have positive optical power, the aberration correction capability of the system can be further optimized. Specifically, the positive optical power third lens 5 can effectively share the optical power distribution of the system, reducing the optical power burden on the first lens 3 and the second lens 4, thereby reducing the amount of aberration generated by each lens. At the same time, the combination of three positive optical power lenses is beneficial to achieving better aberration balance while maintaining the total optical power of the system, especially for better correction of aberrations such as spherical aberration, coma, and field curvature, thereby improving the overall imaging quality.

[0050] Furthermore, in the example including the third lens 5, the camera 6 of the eye-tracking module is still located in the peripheral region A on the third surface 41 side of the second lens 4, and the imaging light path of the camera 6 still reaches the human eye 01 after transmission through the fourth surface 42. That is to say, after adding the third lens 5, the imaging light path of the camera 6 still does not need to pass through the folded light path with lower light efficiency in the first optical component. Therefore, while further improving the imaging quality by adding the third lens 5, the near-eye optical display system can still maintain the high light energy utilization rate of eye tracking and the compactness of the system.

[0051] For example, the optical power range of the first lens 3 is 0.002 to 0.01. The optical power range of the second lens 4 is 0.007 to 0.011. The optical power range of the third lens 5 is 0.011 to 0.016.

[0052] See some examples in this application. Figure 1 and Figure 3 The optical display system further includes a display screen 1, the light-emitting surface of which is provided with protective glass 2. The display screen 1 is located on the image source side and is used to emit image light. On the optical axis, the distance from the fourth surface of the second lens 4, which is closest to the human eye, to the second surface 32 of the first lens 3, which is closest to the human eye, is T5, and the distance from the fourth surface 42 of the second lens 4 to the display screen 1 is T6, and T5 and T6 satisfy: 0.35 < T5 / T6 < 0.83.

[0053] The display screen 1 is located on the image source side and is used to emit image light. Its light-emitting surface is provided with protective glass 2 for physical protection of the display screen 1. On the central optical axis, the distance from the fourth surface 42 of the second lens 4, which is closest to the human eye, to the second surface 32 of the first lens 3 facing the human eye is T5, and the distance from the fourth surface 42 of the second lens 4 to the light-emitting surface of the display screen 1 is T6, and T5 and T6 satisfy: 0.35 < T5 / T6 < 0.83.

[0054] Specifically, T5 is the axial distance along the central optical axis from the fourth surface 42 of the second lens 4 closest to the human eye to the second surface 32 of the first lens 3. This distance includes the central thickness of the second lens 4 itself, and in embodiments with a third lens 5, it also includes the central thickness of the third lens 5 and the air gap between the third lens 5 and the second lens 4 and the first lens 3. The size of T5 directly affects the overall optical length and aberration correction capability of the system. T6 is the axial distance along the central optical axis from the fourth surface 42 of the second lens 4 to the light-emitting surface of the display screen 1, and is a major component of the overall optical length of the system (excluding the thickness of the display screen 1). The ratio of T5 / T6 characterizes the proportion of the overall axial distance from the second surface 32 of the first lens 3 to the fourth surface 42 of the second lens 4 in the total optical distance.

[0055] By controlling T5 / T6 between 0.35 and 0.83, the spacing and thickness between optical elements can be reasonably allocated while ensuring system imaging quality. This avoids an excessively large axial distance leading to an increase in the total optical length, or an excessively small distance making aberration correction difficult. If T5 / T6 is less than or equal to 0.35, T5 is too small, resulting in an excessively short axial distance between the second surface 32 of the first lens 3 and the fourth surface 42 of the second lens 4, which may affect light propagation and aberration correction. If T5 / T6 is greater than or equal to 0.83, T5 is too large relative to T6, leading to an increase in the total optical length of the system, which is detrimental to system miniaturization. This application limits T5 / T6 to the above range, achieving a good balance between imaging quality and system compactness.

[0056] Among them, 3.6mm < T5 < 10.4mm, 10.3mm < T6 < 23.3mm.

[0057] See some examples in this application. Figure 1 and Figure 2 The beam splitter 7 is disposed on the first surface 31 of the first lens 3 facing the image source side; the phase delayer 8 and the polarization reflection element 9 are stacked to form a composite film layer, which is disposed on the second surface 32 of the first lens 3 facing the human eye side or on the surface of the third lens 5 facing the human eye side; wherein, the phase delayer 8 is located between the beam splitter 7 and the polarization reflection element 9.

[0058] The beam splitter 7, the phase retarder 8, and the polarization reflector 9 together constitute the core film structure of the folded optical path. In this application, the beam splitter 7 is disposed on the first surface 31 of the first lens 3 to split the incident light; the phase retarder 8 and the polarization reflector 9 are stacked to form a composite film, which can be disposed at different positions according to the system design requirements.

[0059] In one configuration method, see Figure 1 and Figure 18 The near-eye optical display system adopts a two-lens structure, namely, it includes only a first lens 3 and a second lens 4, and the composite film layer is disposed on the second surface 32 of the first lens 3.

[0060] In another configuration method, see Figure 8 and Figure 13 The near-eye optical display system adopts a three-lens structure, namely, a first lens 3, a third lens 5, and a second lens 4 (arranged sequentially along the optical path), and the composite film layer is disposed on the surface of the third lens 5 facing the human eye.

[0061] Regardless of the configuration method used, the phase delayer 8 is always located between the beam splitter 7 and the polarization reflector 9 to ensure the correct sequence of light polarization state conversion. Simultaneously, the infrared imaging optical path of the camera 6 does not pass through the aforementioned folded optical path, thus effectively avoiding light energy loss caused by infrared light repeatedly penetrating the low-efficiency film layer.

[0062] See some examples in this application. Figure 2 The near-eye optical display system further includes a polarization element 10, which is disposed on the side surface of the polarization reflection element 9 facing away from the phase delayer 8.

[0063] The polarizing element 10 is a polarizing film, and its transmission axis direction is consistent with the transmission axis direction of the polarizing reflective element 9. In the folded optical path, the image light, after multiple reflections and transmissions, exits from the polarizing reflective element 9 in a specific polarization state (e.g., linearly polarized light). The polarizing element 10 allows light of this specific polarization state to pass through, while absorbing or reflecting stray light of other polarization states.

[0064] By introducing the polarization element 10, undesired polarized light generated by reflection or scattering from the element surface in the system can be effectively suppressed, thereby reducing the impact of stray light on imaging contrast and sharpness, and further improving the display quality of virtual images.

[0065] Optionally, an anti-reflective film 11 may be provided on the surface of the polarizing element 10 facing away from the polarizing reflective element 9. The anti-reflective film 11 is used to reduce the reflection loss of light on this surface, improve the light transmittance, and thus further enhance the brightness and contrast of the image.

[0066] In some examples of this application, the total optical length (TTL) of the near-eye optical display system satisfies: 16mm < TTL < 25mm.

[0067] The total optical length (TTL) refers to the axial distance along the central optical axis from the back of the display screen 1 to the lens surface closest to the human eye (i.e., the fourth surface 42 of the second lens 4). Unlike T6, which is defined as the distance from the fourth surface 42 of the second lens 4 to the light-emitting surface of the display screen 1, the two are not numerically equal: TTL includes the thickness of the display screen 1 itself (i.e., the distance from the light-emitting surface of the display screen 1 to the back of the display screen 1). Therefore, the numerical range of TTL (16mm to 25mm) is greater than the numerical range of T6 (e.g., 10.37mm to 23.24mm).

[0068] The total optical length (TTL) of the near-eye optical display system of this application is between 16mm and 25mm, which ensures that the near-eye optical display system has a compact overall structure while meeting the requirements of imaging quality and eye-tracking performance, making it easy to integrate into head-mounted display devices.

[0069] In some examples of this application, the half-aperture D3 of the first lens 3 satisfies: 17mm < D3 < 22mm.

[0070] As mentioned earlier, D3 is the maximum half-aperture of the near-eye optical display system, which is located on the first lens 3. Controlling the half-aperture D3 of the first lens 3 between 17mm and 22mm can effectively control the overall radial dimension of the system while ensuring the light transmission, which is beneficial for achieving miniaturization design of head-mounted display devices.

[0071] The optical system of this application will be described in detail below through Examples 1 to 4.

[0072] Example 1 This embodiment provides a near-eye optical display system, the optical structure and optical path of which are as follows: Figure 1 As shown. The near-eye optical display system includes, along the optical axis from the image source side to the human eye side, a display screen 1, a protective glass 2, a first lens 3, and a second lens 4, and also includes an eye-tracking module.

[0073] In this design, a beam-splitting element 7 is disposed on the first surface 31 facing the image source side of the first lens 3; a composite film layer is disposed on the second surface 32 facing the human eye side of the first lens 3. The composite film layer is composed of a phase retarder 8, a polarization reflection element 9, a polarization element 10, and an anti-reflection film 11, sequentially stacked along the optical path. (See [reference]). Figure 2 .

[0074] The second lens 4 is located between the first lens 3 and the human eye 01, and has a third surface 41 facing the first lens 3 and a fourth surface 42 facing the human eye 01.

[0075] The eye-tracking module includes at least one camera 6 and multiple infrared light sources (not shown in the figure). The camera 6 is disposed on the side of the third surface 41 and located within the peripheral region A of the second lens 4. The peripheral region A does not participate in the virtual imaging of the folded optical path. The third surface 41 is convex in the region corresponding to the camera 6, and the fourth surface 42 is concave in the region corresponding to the camera 6. The imaging optical path of the camera 6 is formed by the eye movement image information of the human eye being refracted by the second lens 4 before reaching the camera 6.

[0076] The parameter satisfaction status in this embodiment 1 is shown in Table 1: Table 1

[0077] Please refer to Table 2 for the optical parameters of this embodiment 1: Table 2

[0078] Please refer to Table 3 for the optical power of the first lens 3 and the second lens 4 in this embodiment 1: Table 3

[0079] See Figure 4 This diagram shows the dot plot of the near-eye optical display system of Embodiment 1. A dot plot refers to the pattern formed by multiple rays emanating from an object point, after passing through the system, where aberrations cause their intersection points with the image plane to no longer converge at a single point, but rather to form a diffuse pattern with a certain dispersion range. This pattern is used to evaluate the imaging quality of the optical system. In Embodiment 1, the maximum value of the diffuse spot of the image point in the dot plot of the near-eye optical display system is less than 7 μm, indicating that the system has excellent aberration correction capabilities and produces clear images.

[0080] See Figure 5 The diagram shows the modulation transfer function (MTF) of the near-eye optical display system in Embodiment 1. The MTF is an important indicator of the imaging sharpness of an optical system, characterized by the contrast between black and white line pairs. In Embodiment 1, the near-eye optical display system has an MTF value greater than 0.5 at a spatial frequency of 40 lp / mm, indicating that the system has high imaging sharpness and contrast.

[0081] See Figure 6 This diagram illustrates the field curvature and distortion of the near-eye optical display system in Embodiment 1. In Embodiment 1, the absolute value of distortion in the near-eye optical display system is less than 35% at the maximum field of view (1 field of view), indicating that the system effectively controls the impact of distortion on image quality while achieving a large field of view. See Figure 7The diagram shows the transverse chromatic aberration of the near-eye optical display system in Embodiment 1. Transverse chromatic aberration, also known as magnification chromatic aberration, refers to the phenomenon where a single polychromatic principal ray from the object side is decomposed into multiple rays of different colors upon exiting from the image side due to the dispersion effect of the optical system. This results in a deviation in the focal position of different wavelengths of light (such as blue and red light) on the image plane. In Embodiment 1, the maximum transverse chromatic aberration value of the near-eye optical display system is less than 80 μm, indicating that the system has good chromatic aberration correction capability and can effectively avoid blurring of edge images caused by chromatic aberration.

[0082] Example 2 This embodiment provides a near-eye optical display system, the optical structure of which is as follows: Figure 8 As shown. The main difference from Embodiment 1 is that a third lens 5 is added between the first lens 3 and the second lens 4 in this embodiment, and the composite film layer is disposed on the surface of the third lens 5 facing the human eye (i.e., the sixth surface 52).

[0083] Specifically, the near-eye optical display system includes, along the optical axis from the image source side to the human eye side, the following components in sequence: display screen 1, protective glass 2, first lens 3, third lens 5, and second lens 4, and also includes an eye-tracking module.

[0084] A beam-splitting element 7 is disposed on the first surface 31 of the first lens 3 facing the image source side. An air gap exists between the first lens 3 and the third lens 5, the distance of which is 0.2mm to 0.5mm, specifically 0.3mm in this embodiment.

[0085] A composite film layer is provided on the sixth surface 52 of the third lens 5 facing the human eye. The composite film layer is composed of a phase delayer 8, a polarization reflection element 9, a polarization element 10 and an anti-reflection film 11 stacked sequentially along the optical path.

[0086] The second lens 4 is located between the third lens 5 and the human eye 01, and has a third surface 41 facing the third lens 5 and a fourth surface 42 facing the human eye 01.

[0087] The eye-tracking module includes at least one camera 6 and multiple infrared light sources (not shown in the figure). The camera 6 is disposed on the side of the third surface 41 and located within the peripheral region A of the second lens 4. The peripheral region A does not participate in the virtual imaging of the folded optical path. The third surface 41 is convex in the region corresponding to the camera 6, and the fourth surface 42 is concave in the region corresponding to the camera 6. The imaging optical path of the camera 6 is formed by the eye movement image information of the human eye being refracted by the second lens 4 before reaching the camera 6.

[0088] The parameter satisfaction status in Example 2 is shown in Table 4: Table 4

[0089] Please refer to Table 5 for the optical parameters of this embodiment 2: Table 5

[0090] Please refer to Table 6 for the optical power of the first lens 3, the third lens 5, and the second lens 4 in this embodiment 2. Table 6

[0091] The near-eye optical display system of this embodiment 2 has the following excellent optical performance: See Figure 9 The dot plot shown shows that the maximum value of the blur spot of the image point is less than 16 μm, indicating that the system aberration correction is good.

[0092] See Figure 10 The modulation transfer function (MTF) plot shown shows that at a spatial frequency of 40 lp / mm, the MTF value is greater than 0.4, indicating that the system has high imaging clarity.

[0093] See Figure 11 The distortion diagram shown shows that at the maximum field of view (field of view 1), the absolute value of the distortion is less than 35%, indicating that the system effectively controls image deformation under a large field of view.

[0094] See Figure 12 The shown vertical axis color difference diagram shows that the maximum vertical axis color difference value is less than 50μm, indicating that the system has good color difference correction capability and no obvious edge image blurring phenomenon.

[0095] Example 3 This embodiment provides a near-eye optical display system, the optical structure of which is as follows: Figure 13 As shown. The main difference from Embodiment 2 is that in this embodiment, the first lens 3 and the third lens 5 are cemented together.

[0096] Specifically, the near-eye optical display system includes, along the optical axis from the image source side to the human eye side, the following components in sequence: display screen 1, protective glass 2, first lens 3, third lens 5, and second lens 4, and also includes an eye-tracking module.

[0097] In this design, a beam splitter 7 is disposed on the first surface 31 of the first lens 3 facing the image source side. The first lens 3 and the third lens 5 are cemented together without any air gap between them, that is, the second surface 32 of the first lens 3 facing the human eye side is bonded to the fifth surface 51 of the third lens 5 facing the image source side.

[0098] A composite film layer is provided on the sixth surface 52 of the third lens 5 facing the human eye. The composite film layer is composed of a phase delayer 8, a polarization reflection element 9, a polarization element 10 and an anti-reflection film 11 stacked sequentially along the optical path.

[0099] The second lens 4 is located between the third lens 5 and the human eye 01, and has a third surface 41 facing the third lens 5 and a fourth surface 42 facing the human eye 01.

[0100] The eye-tracking module includes at least one camera 6 and multiple infrared light sources (not shown in the figure). The camera 6 is disposed on the side of the third surface 41 and located within the peripheral region A of the second lens 4. The peripheral region A does not participate in the virtual imaging of the folded optical path. The third surface 41 is convex in the region corresponding to the camera 6, and the fourth surface 42 is concave in the region corresponding to the camera 6. The imaging optical path of the camera 6 is formed by the eye movement image information of the human eye being refracted by the second lens 4 before reaching the camera 6.

[0101] The parameter satisfaction status in Example 3 is shown in Table 7: Table 7

[0102] Please refer to Table 8 for the optical parameters of this embodiment 3.

[0103] Table 8

[0104] The optical power of the first lens 3, the third lens 5, and the second lens 4 in this embodiment 3 are shown in Table 9. Table 9

[0105] The near-eye optical display system of this embodiment 3 has the following excellent optical performance: See Figure 14 The dot plot shown shows that the maximum value of the blur spot of the image point is less than 30 μm, indicating that the system aberration correction is good.

[0106] See Figure 15 The modulation transfer function (MTF) plot shown shows that at a spatial frequency of 40 lp / mm, the MTF value is greater than 0.4, indicating that the system has high imaging clarity.

[0107] See Figure 16 The distortion diagram shown shows that at the maximum field of view (field of view 1), the absolute value of the distortion is less than 35%, indicating that the system effectively controls image deformation under a large field of view.

[0108] See Figure 17The shown vertical axis color difference diagram shows that the maximum vertical axis color difference value is less than 100μm, indicating that the system has good color difference correction capability and no obvious edge image blurring phenomenon.

[0109] Example 4 This embodiment provides a near-eye optical display system; see [link / reference] Figure 18 Its optical structure is basically the same as that of Example 1, the only difference being the optical parameters.

[0110] Specifically, the near-eye optical display system includes, along the optical axis from the image source side to the human eye side, the following components in sequence: display screen 1, protective glass 2, first lens 3, and second lens 4, and also includes an eye-tracking module.

[0111] The first lens 3 has a beam splitting element 7 disposed on its first surface 31 facing the image source side; the first lens 3 has a composite film layer disposed on its second surface 32 facing the human eye side, the composite film layer being composed of a phase delayer 8, a polarization reflection element 9, a polarization element 10 and an anti-reflection film 11 stacked sequentially along the optical path.

[0112] The second lens 4 is located between the first lens 3 and the human eye 01, and has a third surface 41 facing the first lens 3 and a fourth surface 42 facing the human eye 01.

[0113] The eye-tracking module includes at least one camera 6 and multiple infrared light sources (not shown in the figure). The camera 6 is disposed on the side of the third surface 41 and located within the peripheral region A of the second lens 4. The peripheral region A does not participate in the virtual imaging of the folded optical path. The third surface 41 is convex in the region corresponding to the camera 6, and the fourth surface 42 is concave in the region corresponding to the camera 6. The imaging optical path of the camera 6 is formed by the eye movement image information of the human eye being refracted by the second lens 4 before reaching the camera 6.

[0114] The parameter satisfaction status in Example 4 is shown in Table 10: Table 10

[0115] Please refer to Table 11 for the optical parameters of this embodiment 4.

[0116] Table 11

[0117] Please refer to Table 12 for the optical power of the first lens 3 and the second lens 4 in this embodiment 4: Table 12

[0118] The near-eye optical display system of this embodiment 4 has the following excellent optical performance: See Figure 19 The dot plot shown shows that the maximum value of the blur spot of the image point is less than 16 μm, indicating that the system aberration correction is good.

[0119] See Figure 20 The modulation transfer function (MTF) plot shown: at a spatial frequency of 40 lp / mm, the MTF value is greater than 0.1, indicating that the system has high imaging clarity.

[0120] See Figure 21 The distortion diagram shown shows that at the maximum field of view (field of view 1), the absolute value of the distortion is less than 35%, indicating that the system effectively controls image deformation under a large field of view.

[0121] See Figure 22 The shown vertical axis color difference diagram shows that the maximum vertical axis color difference value is less than 140μm, indicating that the system has good color difference correction capability and no obvious edge image blurring phenomenon.

[0122] The near-eye optical display system provided in this application can be used in optical display devices. The optical display device can be a virtual reality (VR), augmented reality (AR), or other form of head-mounted display device, characterized by its compact size, high eye-tracking accuracy, and excellent imaging quality.

[0123] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0124] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A near-eye optical display system, characterized in that, include: The first optical component is configured to receive image light from an image source and form a folded optical path, and guide the image light to the direction of the human eye. The first optical component includes a first lens (3) and a beam splitter (7) disposed on the image source side of the first lens (3), a phase delayer (8) disposed on the human eye side of the first lens (3), and a polarization reflection element (9). A second optical component, located between the first optical component and the human eye (01), includes a second lens (4) having a third surface (41) facing the first optical component and a fourth surface (42) facing the human eye (01); and, An eye-tracking module includes at least one camera (6), the camera (6) being disposed on the side of the third surface (41) and located in the peripheral region (A) of the second lens (4) not participating in the virtual imaging of the folded optical path, the third surface (41) being convex in the region corresponding to the camera (6); The imaging optical path of the camera (6) is such that the eye movement image information of the human eye is refracted by the second lens (4) and then reaches the camera (6).

2. The near-eye optical display system according to claim 1, characterized in that, The second lens (4) satisfies: 5% < (D2 - D1) / D1 < 22%, where D1 is half the aperture of the optically effective area on the second lens (4) that participates in the virtual imaging of the folded optical path, D2 is half the aperture of the second lens (4), and the peripheral area (A) is the area on the second lens (4) from the edge of the optically effective area to the edge of the second lens (4).

3. The near-eye optical display system according to claim 1 or 2, characterized in that, The near-eye optical display system satisfies: 0.7 < D2 / D3 < 0.9, where D2 is half the aperture of the second lens (4), D3 is half the aperture of the first lens (3), and the aperture of the first lens (3) is greater than the aperture of any other lens in the near-eye optical display system.

4. The near-eye optical display system according to claim 1, characterized in that, The fourth surface (42) of the second lens (4) is any one of convex, concave and flat in the area corresponding to the camera (6).

5. The near-eye optical display system according to claim 1, characterized in that, The first optical component further includes a third lens (5), which is located between the first lens (3) and the second lens (4); The optical power of the first lens (3), the second lens (4) and the third lens (5) is positive.

6. The near-eye optical display system according to claim 5, characterized in that, The optical display system also includes a display screen (1), the light-emitting surface of which is provided with protective glass (2), and the display screen (1) is located on the image source side for emitting image light; On the optical axis, the distance from the fourth surface of the second lens (4) closest to the human eye to the second surface (32) of the first lens (3) closest to the human eye is T5, and the distance from the fourth surface (42) of the second lens (4) to the display screen (1) is T6, and T5 and T6 satisfy: 0.35 < T5 / T6 < 0.

83.

7. The near-eye optical display system according to claim 6, characterized in that, The beam splitting element (7) is disposed on the first surface (31) of the first lens (3) facing the image source side; The phase delayer (8) and the polarization reflection element (9) are stacked to form a composite film layer, which is disposed on the second surface (32) of the first lens (3) facing the human eye or on the surface of the third lens (5) facing the human eye. The phase delayer (8) is located between the beam splitter (7) and the polarization reflection element (9).

8. The near-eye optical display system according to claim 7, characterized in that, It also includes a polarization element (10), which is disposed on the side surface of the polarization reflection element (9) away from the phase delayer (8).

9. The near-eye optical display system according to claim 6, characterized in that, The total optical length (TTL) of the near-eye optical display system satisfies: 16mm < TTL < 25mm.

10. The near-eye optical display system according to claim 3, characterized in that, The half-aperture D3 of the first lens (3) satisfies: 17mm < D3 < 22mm.

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