Optical projection system and ar optical device

Abstract

The embodiment of the application discloses an optical projection system and an AR optical device; the optical projection system comprises an AR light machine; the AR light machine comprises a polarization reflection element, a first phase retarder and a light splitting element arranged along the same optical axis, and the first phase retarder is located between the polarization reflection element and the light splitting element; the optical projection system further comprises a first lens, the first lens is located between the first phase retarder and the light splitting element, the polarization reflection element and the first phase retarder are stacked to form a superposition element, and the superposition element is arranged on the side surface of the first lens away from the light splitting element.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical display, and in particular, the present application relates to an optical projection system and an AR optical device. BACKGROUND

[0002] In the AR optical device, the AR light machine as a key optical component, its performance and volume directly affect the user experience. The miniaturization of the AR light machine has been an important goal pursued in the industry. In the prior art, the light machine based on the μLED technology (i.e., based on the Micro-LED technology) is considered by the industry as the development direction to realize the miniaturization of the AR light machine due to its small size and great potential for display performance.

[0003] At present, the industry has realized the mass production of a single green light machine based on the μLED technology, and the number of optical lenses thereof is about 4-5, the overall optical length is about 7.5 mm, and the corresponding light machine volume is about 0.3 cc. However, in order to pursue more extreme volume compression, the industry is actively exploring new technical solutions. By introducing more aspheric lenses, the lens length based on 5 aspheric lenses has been successfully compressed to 5.6 mm, and the corresponding light machine volume is also reduced to 0.15 cc, which is the limit of the traditional light machine design. It can be seen that although the volume of the light machine has been reduced, there is still room for further optimization. SUMMARY

[0004] The purpose of the present application is to provide a new technical solution of an optical projection system and an AR optical device.

[0005] According to a first aspect of the present application, an optical projection system is provided, the optical projection system comprising an AR light machine;

[0006] The AR light machine comprises a polarization reflection element, a first phase retarder, and a light splitting element arranged along the same optical axis, and the first phase retarder is located between the polarization reflection element and the light splitting element;

[0007] The optical projection system further comprises a first lens located between the first phase retarder and the light splitting element, the polarization reflection element and the first phase retarder are stacked to form a superposition element, and the superposition element is arranged on the side surface of the first lens away from the light splitting element.

[0008] Optionally, the optical projection system comprises a light waveguide sheet for propagating the projection light rays emitted by the AR light machine to a target position for imaging;

[0009] The distance between the exit pupil position of the AR light machine and the entrance pupil position of the light waveguide sheet is 2-5 mm.

[0010] Optionally, the first lens sets a radius of curvature of a surface of the superposition element as R1, and R1>15 mm.

[0011] Optionally, the AR light machine comprises a screen, the screen is arranged on a side of the light splitting element away from the first phase retarder along the optical axis, an image height of the screen is H, and 0

[0012] Optionally, the light splitting element is arranged on an outcoupling surface of the screen.

[0013] Optionally, an outcoupling surface of the screen is superposed with a second phase retarder and a polarization element, the second phase retarder and the polarization element are used for converting light emitted by the screen into circularly polarized light.

[0014] The light splitting element is superposed on a side of the second phase retarder away from the polarization element, and the light splitting element, the second phase retarder and the polarization element form a composite film material.

[0015] Optionally, a protective glass is arranged on the outcoupling surface of the screen, and the protective glass is located between the composite film material and the outcoupling surface of the screen.

[0016] Optionally, along the optical axis direction, a distance from the light splitting element to the outcoupling surface of the screen is L1, and 0.1 mm≤L1≤1.5 mm.

[0017] Optionally, the screen and the first lens are arranged adjacent to each other, and an air gap between the screen and the first lens is ≥0.1 mm.

[0018] A focal length of the first lens is F1, and 5 mm≤F1≤20 mm.

[0019] Optionally, the AR light machine further comprises a second lens, the second lens is located between the first lens and the screen, the screen and the second lens are arranged adjacent to each other, and an air gap between the screen and the second lens is ≥0.1 mm.

[0020] A combined focal length of the first lens and the second lens is F 12 , and 5 mm≤F 12 ≤20 mm.

[0021] Optionally, a focal length of the first lens is F1, and 2 mm≤F1≤10 mm.

[0022] A focal length of the second lens is F2, and 20 mm≤F2≤50 mm.

[0023] Optionally, the AR light engine further comprises a second lens and a third lens, the screen and the third lens are adjacently arranged, and the second lens is located between the first lens and the third lens, and an air gap between the screen and the third lens is ≥0.1mm.

[0024] A combined focal length of the first lens, the second lens and the third lens is F 123 , 5mm≤F 123 ≤15mm.

[0025] Optionally, a focal length of the first lens is F1, 1mm≤F1≤5mm.

[0026] A focal length of the second lens is F2, -10mm≤F2≤-1mm.

[0027] A focal length of the third lens is F3, 15mm≤F3≤350mm.

[0028] Optionally, a radius of curvature of a surface of the superposition element arranged by the first lens is R1, R1>20mm.

[0029] Optionally, an overall length of the AR light engine is L, 1mm≤L≤6mm.

[0030] Optionally, a distance from the polarization reflection element to a position of an exit pupil of the AR light engine is PD, 0≤PD≤10mm.

[0031] Optionally, an overall focal length of the AR light engine is F, 2.5mm≤F≤10mm.

[0032] According to a second aspect of the present application, an AR optical device is provided, the AR optical device comprising the optical projection system according to the first aspect.

[0033] One beneficial effect of the embodiment of the present application is that:

[0034] The optical projection system according to the embodiment of the present application, wherein the AR light engine is a light engine based on μLED technology (i.e., based on Micro-LED technology), by ingeniously introducing a polarization reflection element, a first phase retarder and a light splitting element at key positions in the optical architecture, a high-efficiency folded optical path system is built, and the number of lenses used is optimized, thereby creating a compact and efficient optical architecture layout, and finally realizing the miniaturization design of the optical projection system while maintaining good imaging display performance. The present application provides strong support for improving the wearing comfort of the AR optical device.

[0035] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0037] Figure 1 This is a schematic diagram of the structure of the optical projection system provided in the embodiments of this application;

[0038] Figure 2 An optical architecture and optical path diagram of an AR optical engine provided in one embodiment of this application;

[0039] Figure 3 for Figure 2 The diagram shows an optical architecture and optical path of an AR optical engine.

[0040] Figure 4 for Figure 3 The MTF diagram of the AR optical engine is shown;

[0041] Figure 5 for Figure 3 The dot array diagram of the AR optical engine is shown;

[0042] Figure 6 for Figure 3 The diagram shows the optical distortion of the AR optical mechanism;

[0043] Figure 7 for Figure 3 The relative illumination diagram of the AR optical engine is shown;

[0044] Figure 8 An optical architecture and optical path diagram of an AR optical engine provided in another embodiment of this application;

[0045] Figure 9 for Figure 8 The diagram shows an optical architecture and optical path of an AR optical engine.

[0046] Figure 10 for Figure 9 The MTF diagram of the AR optical engine is shown;

[0047] Figure 11 for Figure 9 The dot array diagram of the AR optical engine is shown;

[0048] Figure 12 for Figure 9 The diagram shows the optical distortion of the AR optical mechanism;

[0049] Figure 13 for Figure 9 The relative illumination diagram of the AR optical engine is shown;

[0050] Figure 14An optical architecture and an optical path diagram of an AR light machine provided for another embodiment of the present application;

[0051] Figure 15 For Figure 14 An optical architecture and an optical path diagram of an AR light machine provided for another embodiment of the present application;

[0052] Figure 16 For Figure 15 An MTF diagram of an AR light machine provided for another embodiment of the present application;

[0053] Figure 17 For Figure 15 A spot array diagram of an AR light machine provided for another embodiment of the present application;

[0054] Figure 18 For Figure 15 An optical distortion diagram of an AR light machine provided for another embodiment of the present application;

[0055] Figure 19 For Figure 15 A relative luminance diagram of an AR light machine provided for another embodiment of the present application.

[0056] BRIEF DESCRIPTION OF DRAWINGS

[0057] 1, first lens; 101, first surface; 102, second surface; 2, second lens; 3, third lens; 4, screen; 5, polarized reflection element; 6, first phase retarder; 7, light splitting element; 8, second phase retarder; 9, polarized element; 10, protective glass; 12, optical waveguide sheet; 13, lens group; 14, projection imaging light; 01, human eye. DETAILED DESCRIPTION

[0058] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of the components and steps set forth in the examples, as well as the numerical expressions and values, are not limitations on the scope of the present application unless otherwise specifically stated.

[0059] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the scope of the application, its application, or uses.

[0060] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and devices can be viewed as part of the specification.

[0061] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0062] It should be noted that like numerals and letters refer to like items throughout the several views, as such, once an item is defined in one view, it need not be discussed further in subsequent views.

[0063] The optical projection system and the AR optical device provided by the embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0064] According to an embodiment of the present application, an optical projection system is provided, referring to Figures 1 to 3 , the optical projection system comprises an AR light machine; the AR light machine comprises a polarization reflection element 5, a first phase retarder 6, and a light splitting element 7 arranged along the same optical axis, and the first phase retarder 6 is located between the polarization reflection element 5 and the light splitting element 7; the optical projection system further comprises a first lens 1, which is located between the first phase retarder 6 and the light splitting element 7, the polarization reflection element 5 and the first phase retarder 6 are stacked to form a superposition element, and the superposition element is arranged on the side surface of the first lens 1 away from the light splitting element 7.

[0065] It should be noted that the optical projection system provided by the embodiment of the present application is designed based on the optical waveguide architecture, which is the design of the exit lens part of the AR light machine based on the optical waveguide architecture.

[0066] The optical projection system provided by the embodiment of the present application, referring to Figures 1 to 3 , shows its unique and efficient optical architecture. First, the polarization reflection element 5, the first phase retarder 6, at least the first lens 1, and the light splitting element 7 arranged along the same optical axis are introduced into the optical architecture of the AR light machine, which ensures that the light can propagate according to the predetermined folding path inside the AR light machine. Among them, the first phase retarder 6 is located between the polarization reflection element 5 and the light splitting element 7, which provides a basis for polarization control and path separation of light.

[0067] In the optical scheme provided by the embodiment of the present application, referring to Figure 2 and Figure 3 , the optical architecture of the AR light machine can use only one lens, i.e. the first lens 1. Specifically, the first lens 1 is located between the first phase retarder 6 and the light splitting element 7, and the projection light entering the AR light machine can pass through the first lens 1 three times during the turning process, referring to Figure 3This layout can prolong the propagation path of light rays, so that the light rays are more fully regulated and optimized inside the optical projection system. This way of passing the light rays through the same lens three times not only enhances the utilization rate of light rays, but also helps to eliminate aberrations and improve the clarity of the image. Through such an efficient and compact optical architecture, the optical projection system provided by the embodiments of the present application realizes excellent optical performance while maintaining miniaturization and compactness, and can bring users a clearer visual experience.

[0068] Regarding the design of the number of lenses, the AR light machine provided by the embodiments of the present application can use at least one lens, i.e. Figure 2 the first lens 1 shown in FIG. 1. In actual applications, in order to meet more complex optical performance requirements, 1-2 lenses can be added to the AR light machine, see Figure 8 and Figure 14 These additional lenses can be selected and designed as needed to further optimize the optical path, improve image quality, or achieve other special optical functions.

[0069] For example, when two or more lenses are used in the AR light machine, a lens group 13 as shown in Figure 1 can be formed. With the appropriate increase in the number of lenses, the final image quality can be improved.

[0070] The optical projection system provided by the embodiments of the present application, in which the AR light machine is based on folded optical design and can use a single lens, significantly reduces the items in the BOM bill of materials of the optical projection system, not only simplifying the manufacturing process, but also directly and effectively reducing the cost of the product. This cost optimization is of great significance to improving the market competitiveness of the product.

[0071] By flexibly adjusting the number and layout of lenses, the optical projection system provided by the embodiments of the present application can achieve high-performance imaging effects while ensuring compactness. In addition, due to the precise layout and combination of optical elements inside the optical projection system, the optical projection system also has good stability and reliability, and can meet the use requirements in various complex environments.

[0072] The light splitting element 7 is, for example, a semi-transparent and semi-reflective film that transmits a portion of the light rays and reflects another portion of the light rays. It should be noted that the reflectivity and transmissivity of the light splitting element 7 can be flexibly adjusted according to specific needs, which is not limited in the embodiments of the present application.

[0073] The first phase retarder 6 can be used to change the polarization state of light. For example, for converting linearly polarized light into circularly polarized light, or converting circularly polarized light into linearly polarized light. The first phase retarder 6 in the present application is, for example, a quarter-wave plate. Of course, the first phase retarder 6 can be set as other phase retardation films as needed.

[0074] The polarization reflection element 5 is a polarization reflector that reflects horizontally linearly polarized light and transmits vertically linearly polarized light, or any other specific angle linearly polarized light and transmits linearly polarized light perpendicular to the angle.

[0075] In the AR light machine provided in the embodiments of the present application, referring to Figure 2 , the cooperation of the light splitting element 7, the first lens 1, the first phase retarder 6, and the polarization reflection element 5 can accurately control the propagation and polarization state of light, so that a clear and accurate image can be obtained.

[0076] It is worth noting that in the present application, the polarization reflection element 5 and the first phase retarder 6 are designed in a stacked manner to form a superposition element. This superposition arrangement saves space inside the AR light machine, which is conducive to making the structure of the AR light machine more compact, and at the same time, it is conducive to reducing the assembly complexity of the optical projection system.

[0077] The polarization reflection element 5 and the first phase retarder 6 are attached to the left side surface (i.e. the first surface 101) of the first lens 1, referring to Figure 2 This layout can make the light fold completely and pass through the two surfaces of the first lens 1. This design not only optimizes the optical path, but also fully utilizes the correction aberration ability of the lens surface, thereby significantly improving the imaging quality and user experience.

[0078] In addition, the superposition element described above is arranged on the side surface of the first lens 1 away from the light splitting element 7. Such a layout makes the light fold and pass through the first lens 1 three times, which can effectively correct the aberration.

[0079] Referring to Figure 2 and Figure 3, the light path of the optical projection system is: the screen 4 emits light, which is modulated into circularly polarized light → 50% of the circularly polarized light is transmitted and 50% is reflected after passing through the light splitting element 7 → the circularly polarized light is transmitted (in addition, the circularly polarized light of the reflected part becomes P light after passing through the second phase retarder 8 on the surface of the screen 4, and the P light is absorbed after passing through the polarization element 9) → the first time passing through the first lens 1 to correct aberration → passing through the first phase retarder 6 to become P light → the P light reaches the polarization reflection element 5 (anti-P light, S light is transmitted) and is reflected → the P light becomes circularly polarized light after passing through the first phase retarder 6 → the second time passing through the first lens 1 to correct aberration → 50% of the light is reflected after passing through the light splitting element 7 → the third time passing through the first lens 1 to correct aberration → the circularly polarized light becomes S light after passing through the first phase retarder 6 → the S light transmits the polarization reflection element 5 → exits to the optical transmission device (such as the optical waveguide sheet 12), and finally forms an image in the human eye 01.

[0080] The optical projection system provided by the embodiment of the application, wherein the AR light machine is a light machine based on μLED technology (that is, based on Micro-LED technology), by ingeniously introducing the polarization reflection element 5, the first phase retarder 6 and the light splitting element 7 at key positions in the optical architecture, a high-efficiency folded light path system is constructed, and the number of lenses used is optimized, thereby creating a compact and efficient AR light machine optical architecture layout, which can realize miniaturization design of the optical projection system while maintaining good imaging display performance. The optical projection system provided by the application provides strong support for improving the wearing comfort of the AR optical equipment.

[0081] The technical scheme provided by the embodiment of the application not only realizes miniaturization of the optical projection system, but also maintains compactness without compromising the optical display performance, thereby ensuring that the user can enjoy good visual experience during use. The miniaturization design of the optical projection system brings advantages to the wearing comfort of the AR optical equipment, so that the user can also feel relaxed when wearing and using for a long time.

[0082] The optical projection system provided by the embodiment of the application is designed based on the light waveguide architecture, and the light emitted by the optical projection system is transmitted to the human eye 01 through the optical waveguide sheet 12 for imaging.

[0083] In some examples of the application, referring to Figure 1 , the optical projection system comprises an optical waveguide sheet 12, which is used to propagate the projection light emitted by the AR light machine to a target position for imaging; the distance between the exit pupil position of the AR light machine and the entrance pupil position of the optical waveguide sheet 12 is 2mm-5mm.

[0084] In optical projection systems, optical waveguides (such as diffractive waveguides) are needed to propagate the projection light emitted from the optical engine to the target position for imaging. In this application, the exit pupil of the AR optical engine must match the entrance pupil of the optical waveguide 12.

[0085] It should be noted that an optical waveguide is a special type of optical transmission device that uses the principle of total internal reflection to propagate light (such as projected light) along a specific path.

[0086] In this embodiment, the main function of the optical waveguide 12 is to effectively propagate the projection light emitted from the AR optical engine to the target location (e.g., Figure 1 Image is coupled out at the location of the human eye (01) shown in the diagram, and the optical waveguide 12 can couple out the projected imaging light 14. This allows the AR image to be presented at a specific position and angle in the user's field of vision.

[0087] The design and optimization of the optical waveguide 12 are crucial for improving optical efficiency. An efficient optical waveguide reduces light loss during propagation, ensuring that projected light reaches the target location with sufficient brightness and clarity.

[0088] As mentioned in the example above in this application, the distance between the exit pupil of the AR optical engine and the entrance pupil of the optical waveguide 12 in the optical projection system is 2mm to 5mm. This distance range is crucial for ensuring the compactness and optical imaging performance of the entire optical projection system.

[0089] Furthermore, since the AR optical engine needs to be matched with the optical waveguide 12, and the optical waveguide 12 requires parallel light incident, that is, the AR optical engine emits parallel light, and the imaging distance corresponds to infinity.

[0090] See Figure 1 , Figure 1 The projection optical engine shown includes a lens group 13, which includes a plurality of lenses, such as Figure 1 The image shows three lenses. Of course, the projection optical engine of this application can also use only one lens, such as... Figure 2 The first lens 1 is shown in the figure.

[0091] In some examples of this application, the first lens 1 is configured with a surface curvature radius of R1, where R1 > 15 mm.

[0092] In the example provided in this application, the radius of curvature of the coated lens—that is, the first lens 1—in the AR optical engine has been optimized.

[0093] For example, for the first lens 1 in the AR optical engine, the curvature radius R1 of the surface on which the polarization reflection element 5 and the first phase retarder 6 are attached is designed to be greater than 15 mm. This design choice ensures that the first lens 1 can effectively realize the polarization reflection of light and improve the imaging quality.

[0094] The polarization reflection element 5 is, for example, a polarization reflection film.

[0095] The first phase retarder 6 is, for example, a quarter-wave plate.

[0096] Referring to Figure 2 , the first lens 1 includes a first surface 101 on the left side and a second surface 102 on the right side, and the superposition element (i.e., the polarization reflection element 5 and the first phase retarder 6) is arranged on the first surface 101. It should be noted that since the light splitting element 7 is located outside the second surface 102 of the first lens 1, the light entering the optical projection system can pass through the first lens 1 three times during folding, which can effectively correct aberration and improve the imaging quality.

[0097] When only one optical lens, i.e., the first lens 1 shown in Figure 2 , is used in the AR optical engine, the curvature radius of the first surface 101 (left surface) of the first lens 1 is designed to be greater than 15 mm, which can reduce the difficulty of the curved film attachment process and improve the efficiency and yield of mass production. That is, this optimization not only improves the manufacturing efficiency of the product, but also ensures the stability of the product quality.

[0098] In some examples of the present application, referring to Figure 2 , Figure 8 , and Figure 14 , the AR optical engine includes a screen 4, which is arranged on the side of the light splitting element 7 away from the first phase retarder 6 along the optical axis, and the image height of the screen 4 is H, 0 < H ≤ 7.7 mm.

[0099] In the examples provided in the present application, the design of the optical projection system particularly focuses on the matching and optimization of the screen size (image height) and the entire optical path system. By Figure 2 , Figure 8 , and Figure 14 , it can be seen that the AR optical engine provided in the present application includes a screen 4, which is arranged on the side of the light splitting element 7 away from the first phase retarder 6 along the optical axis, and particularly, the matching image height H of the screen 4 is limited to the range of 0 < H ≤ 7.7 mm. This design choice is based on the requirement of miniaturization design of the AR optical engine.

[0100] It should be noted that in the AR optical device, the volume and weight of the optical projection system inside the AR optical device are limited due to the need to consider the wearing comfort and portability of the user. The size (e.g. height) of the screen is a key parameter in the optical projection system, and its size directly affects the overall size and performance of the entire optical projection system.

[0101] For the screen used in the optical projection system, inches can be used to describe its diagonal size.

[0102] Under the miniaturization trend of the AR optical machine, the matching screen size is getting smaller and smaller. For example, in this application, a screen smaller than 0.3 inches is used, which corresponds to a matching image height range of 0-7.7 mm. This screen size range not only meets the miniaturization requirements of the AR optical projection system, but also ensures sufficient imaging display clarity and user visual experience.

[0103] The optical projection system provided by the embodiments of the present application is matched with a small-sized screen 4. By limiting the matching image height H of the screen 4 to the range of 0<H≤7.7 mm, the optical projection system can maintain a small volume and weight, meeting the requirements of portability and wearing comfort of the AR optical device. The matching design of the screen size enables the various elements in the optical system to work better in coordination, reduces light energy loss, and improves imaging quality. The smaller screen size does not significantly affect the user's visual experience, but rather through the optimization of the optical system and display technology, it can provide clearer and more realistic virtual images, enhancing the user's sense of immersion.

[0104] It should be noted that the miniaturized optical projection system is not only suitable for AR optical devices, but also can be applied to other fields requiring compact optical systems, such as micro projectors, etc.

[0105] The screen 4 mentioned in this application is, for example, a light-emitting chip, etc.

[0106] In some examples of the present application, referring to Figure 2 , the light splitting element 7 is disposed on the light output surface of the screen 4.

[0107] In the design of the optical projection system, referring to Figure 2 , the light splitting element 7 is coated or directly attached to the light output surface of the screen 4. The light splitting element 7 uses a semi-transparent and semi-reflective film technology, which not only ensures the reasonable distribution of light, but also significantly optimizes the optical layout.

[0108] In particular, the light splitting element 7 cooperates with the first phase retarder 6 and the polarization reflection element 5 on the surface of the first lens 1 away from the screen 4 to jointly construct a folded light path system. This design enables the first lens 1 to be located in the folded light path, and the light can pass through the lens three times during the turning-back process. This design greatly improves the performance of the AR light machine, especially in terms of aberration correction. The fine adjustment of the light passing through the first lens 1 three times not only reduces the distortion and chromatic aberration in the light path, but also significantly improves the clarity and accuracy of the imaging.

[0109] Moreover, the light splitting element 7 is directly arranged on the light emitting surface of the screen 4, which can minimize the loss of light during transmission and improve the utilization of light energy. This is because after the light is emitted from the screen 4, it can directly encounter the light splitting element 7 without passing through an additional air layer, reducing refraction and scattering of the light.

[0110] In addition, the arrangement of the light splitting element 7 on the screen 4 also eliminates the need for additional supporting elements, simplifying the assembly of the optical projection system and reducing manufacturing costs and maintenance difficulty.

[0111] In some examples of the present application, referring to Figure 2 , the light emitting surface of the screen 4 is stacked with a second phase retarder 8 and a polarization element 9, which are used to convert the light emitted by the screen 4 into circularly polarized light; the light splitting element 7 is stacked on the side of the second phase retarder 8 away from the polarization element 9, and the light splitting element 7, the second phase retarder 8 and the polarization element 9 form a composite film.

[0112] Referring to Figure 2 , the light emitting surface of the screen 4 is designed with a composite film mainly composed of a second phase retarder 8, a polarization element 9 and a light splitting element 7. This integrated design greatly simplifies the assembly process of the optical projection system, and multiple key optical elements can be efficiently integrated into the optical projection system in one assembly.

[0113] Notably, the light splitting element 7 cooperates with the first phase retarder 6 and the polarization reflection element 5 to jointly construct an efficient folded light path. This design not only optimizes the light path layout, but also improves the utilization of light energy.

[0114] In particular, the combination of the second phase retarder 8 and the polarization element 9 can convert the light emitted by the screen 4 into circularly polarized light through optical control technology. This conversion not only enhances the stability and consistency of the light, but also improves the clarity and contrast of the final imaging, providing users with a better visual experience.

[0115] Further, the second phase retarder 8 is stacked on the light-out surface of the screen 4, which mainly functions to phase-delay the light, and the second phase retarder 8 is, for example, a quarter-wave plate. The polarizing element 9 is, for example, a polarizing film, which functions to further adjust the polarization state of the light, and finally converts the light into circularly polarized light.

[0116] The light-splitting element 7 is stacked on the side surface of the second phase retarder 8 away from the polarizing element 9, i.e., on the outermost layer of the composite film material. This design makes the light emitted from the screen 4 first converted into circularly polarized light when passing through the composite film material, and then subjected to light-splitting processing by the light-splitting element 7. The light-splitting element 7, as a semi-transparent and semi-reflective film, can reflect part of the circularly polarized light into the aperture or human eye to form a virtual image for the user to view, while allowing another part of the light to be transmitted for other optical processing or imaging.

[0117] In this application, by converting the light emitted from the screen 4 into circularly polarized light, the loss and interference of the light in the transmission process can be reduced, the brightness and contrast of the virtual image can be improved, and thus the visual experience of the user can be enhanced. The composite film material composed of the light-splitting element 7, the second phase retarder 8, and the polarizing element 9 is arranged on the light-out surface of the screen 4, which simplifies the structure of the optical path system and improves the integration of the optical projection system. At the same time, this design also makes the light more efficiently transmitted and processed, reducing the loss of optical energy.

[0118] In some examples of the present application, referring to Figure 2 , a protective glass 10 is arranged on the light-out surface of the screen 4, and the protective glass 10 is located between the composite film material and the light-out surface of the screen 4.

[0119] Figure 2 It is shown that the light-out surface of the screen 4 is provided with a layer of protective glass 10, and the protective glass 10 is located between the composite film material (including the second phase retarder 8, the polarizing element 9, and the light-splitting element 7) and the light-out surface of the screen 4. This layout not only enhances the overall structural stability of the optical projection system, but also brings the following significant technical effects:

[0120] (1) The protective glass 10 can effectively prevent the light-out surface of the screen 4 from being scratched, impacted, or contaminated by external damage, thereby prolonging the service life of the optical projection system.

[0121] (2) The protective glass 10 is usually made of high-transmittance material, which can ensure that the optical performance of the light emitted from the screen 4 will not be significantly affected when passing through the protective glass. This helps to maintain the clarity and brightness of the output light of the optical projection system.

[0122] (3) By directly setting the protective glass 10 on the light-emitting surface of the screen 4 and assembling together with the composite film material, the assembly process of the optical projection system can be simplified, and the production efficiency is improved.

[0123] In some examples of the present application, referring to Figure 2 , Figure 8 and Figure 14 , the distance between the light-splitting element 7 and the light-emitting surface of the screen 4 along the optical axis direction is L1, and 0.1mm≤L1≤1.5mm.

[0124] In combination with Figure 2 , Figure 8 and Figure 14 , it can be seen that there is a certain distance between the light-splitting element 7 and the light-emitting surface of the screen 4 along the optical axis direction, which is defined as L1, and L1 is controlled in the range of 0.1mm-1.5mm. This design parameter is set based on a series of actual process and technical requirements.

[0125] Firstly, the setting of this distance range takes into account the adaptability of different screens and their process requirements. The screen 4 can come from different suppliers and have different thicknesses, light transmittances and surface treatment methods. At the same time, between the screen 4 and the light-splitting element 7, there can be multiple layers of glue, a second phase retarder 8 (QWP film), a polarization element 9 (POL film), a film-attached substrate glass sheet, and a protective glass 10 of the screen 4, etc. These intermediate layers have a significant impact on the transmission, reflection and polarization state of light.

[0126] Controlling the distance L1 between the light-splitting element 7 and the light-emitting surface of the screen 4 in the range of 0.1mm-1.5mm can ensure that the optical performance (such as brightness, contrast and color saturation) of the light is maintained to the greatest extent when passing through these intermediate layers. Too short or too long distance can cause unnecessary attenuation, scattering or change of polarization state of light during transmission, thereby affecting the final optical effect.

[0127] In addition, the setting of this distance range also takes into account the convenience and reliability of assembly. During the assembly process of the optical projection system, it is necessary to ensure the accurate alignment and fixation between the light-splitting element 7 and the screen 4. An appropriate distance range can provide sufficient operating space while ensuring the accuracy and stability of the assembly.

[0128] In some examples of the present application, referring to Figure 2 and Figure 3 , the screen 4 is arranged adjacent to the first lens 1, and the air gap between the screen 4 and the first lens 1 is ≥0.1mm. The focal length of the first lens 1 is F1, and 5mm≤F1≤20mm.

[0129] Referring to Figure 1 When only one optical lens, i.e., the first lens 1, is used in the optical projection system, the first lens 1 is arranged adjacent to the screen 4, and the first lens 1 is also the first lens on the near-screen side. In this case, the air gap between the first lens 1 and the screen 4 is designed to be greater than or equal to 0.1 mm.

[0130] The use of only the first lens 1 in the AR light engine helps to reduce the volume and weight, thereby meeting the design goal of miniaturization of the light engine. However, in order to ensure that necessary performance adjustments can be made during actual assembly, such as the use of six-axis AA (Active Alignment) of the screen and optical lens to adjust the MTF (Modulation Transfer Function) and the like, a certain gap must be left between the screen 4 and the first lens 1. The minimum value of this gap is set to 0.1 mm, which is based on the consideration of the current process limit.

[0131] The focal length F1 of the first lens 1 is set in the range of 5 mm to 20 mm. Such a design is based on the pursuit of the miniaturization goal of the light engine and the consideration of actual assembly and performance adjustment. Selecting an appropriate focal length in the above range can ensure the imaging quality while achieving miniaturization and light weight of the entire optical projection system.

[0132] In some examples of the present application, referring to Figure 8 and Figure 9 , the optical projection system further comprises a second lens 2, the second lens 2 is located between the first lens 1 and the screen 4, and the screen 4 is arranged adjacent to the second lens 2, and the air gap between the screen 4 and the second lens 2 is ≥0.1 mm. The combined focal length of the first lens 1 and the second lens 2 is F 12 , 5 mm ≤ F 12 ≤ 20 mm.

[0133] Referring to Figure 8 and Figure 9 , the second lens 2 is added in the AR light engine, and the second lens 2 is designed to be located between the first lens 1 and the screen 4. In other words, in this example, two lenses are used in the AR light engine, the added second lens 2 is located on the near-screen side, and it becomes the lens closest to the screen 4, and the first lens 1 is the lens farthest from the screen 4. Based on this, the screen 4 is arranged adjacent to the second lens 2, and the air gap between them is designed to be greater than or equal to 0.1 mm.

[0134] The air gap between the screen 4 and the second lens 2 is designed to be greater than or equal to 0.1 mm, which is based on the consideration of the current process limit. This design ensures that necessary performance adjustments can be made during the actual assembly process, such as using the six-axis AA (Active Alignment) of the screen and optical lens to adjust the MTF (Modulation Transfer Function) and other performances. At the same time, the appropriate gap also improves the convenience and reliability of assembly.

[0135] By adding the second lens 2 in the optical projection system, the AR light machine can achieve more precise control of light. The second lens 2 can adjust the convergence or divergence of light as needed, thereby improving the imaging quality of the entire optical projection system. This design has a positive impact on improving image clarity, contrast, and color restoration, etc.

[0136] In this example of the present application, when two optical lenses are used in the AR light machine: the first lens 1 and the second lens 2, the combined focal length F 12 of the first lens 1 and the second lens 2 is set in the range of 5mm~20mm, such focal length selection enables the AR light machine to achieve better optical performance while maintaining a small volume, thereby improving the optical performance of the optical projection system.

[0137] In some examples of the present application, referring to Figure 8 and Figure 9 , the focal length of the first lens 1 is F1, 2mm≤F1≤10mm; the focal length of the second lens 2 is F2, 20mm≤F2≤50mm.

[0138] In this example provided by the present application, the focal length F1 of the first lens 1 is designed in the range of 2mm~10mm, and the focal length F2 of the second lens 2 is designed in the range of 20mm~50mm, so that through the collocation of the two lenses, the combined focal length F 12 satisfies: 5mm≤F 12 ≤20mm.

[0139] Specifically, the first lens 1 is designed with a short focal length (2mm~10mm), and the second lens 2 is designed with a long focal length (20mm~50mm). By reasonably collocating the focal lengths of the first lens 1 and the second lens 2, the imaging quality of the optical projection system can be optimized. The combination of short focal length and long focal length helps to reduce optical distortion and chromatic aberration, and improve the clarity and color restoration of the image.

[0140] Meanwhile, by adjusting the relative position between the two lenses (the first lens 1 and the second lens 2), the imaging performance of the optical projection system can be further adjusted, so as to realize more accurate image focusing and higher imaging quality.

[0141] The examples provided in the present application can reasonably design the combined focal length F of the first lens 1 and the second lens 2 by carefully selecting the focal length of the first lens 1 and the second lens 2. 12 The range is realized, which significantly improves the imaging quality, system flexibility, miniaturization and convenient assembly and adjustment of the optical projection system.

[0142] In some examples of the present application, referring to Figure 14 and Figure 15 , the AR light machine further comprises a second lens 2 and a third lens 3, the screen 4 and the third lens 3 are adjacently arranged, and the second lens 2 is located between the first lens 1 and the third lens 3, the air gap between the screen 4 and the third lens 3 is ≥0.1mm. The combined focal length of the first lens 1, the second lens 2 and the third lens 3 is F 123 , 5mm≤F 123 ≤15mm.

[0143] In this example of the present application, the AR light machine adopts a design of three optical lenses, that is, the first lens 1, the second lens 2 and the third lens 3 shown in Figure 14 . Compared with single lens or double lens, this design has higher optimization potential of optical performance. Moreover, the design of three lens combination also makes the AR light machine have a larger focal length adjustment range.

[0144] The optical projection system provided in the embodiments of the present application can only use 1 to 3 lenses, compared with 4 to 5 lenses in the conventional design, this design significantly reduces the number of optical lenses. This simplification not only brings cost reduction, but also because of the reduction of optical lenses, the whole optical structure is more compact, which is beneficial to the miniaturization and light weight of the optical projection system.

[0145] It should be noted that the optical projection system provided in the embodiments of the present application can improve the imaging quality with the increase of the number of lenses.

[0146] In this example of the present application, referring to Figure 14 and Figure 15The third lens 3 is the optical lens closest to the screen 4. The screen 4 and the third lens 3 are adjacent to each other, and the air gap between them is designed to be greater than or equal to 0.1 mm. This is based on the current process limit. This design ensures that necessary performance adjustments can be made during actual assembly, such as using six-axis AA (Active Alignment) of the screen and optical lens to adjust MTF (Modulation Transfer Function) and other performances. At the same time, the appropriate air gap improves the convenience and reliability of assembly.

[0147] In addition, the appropriate air gap also helps to prevent direct contact between the screen and the adjacent lens, avoiding scratches or contamination, and maintaining the stability of the optical performance of the optical projection system.

[0148] In this example of the present application, the combined focal length F 123 is designed to be in the range of 5 mm to 15 mm. Through the combined design and optimization of the three lenses, the AR light machine can achieve high-quality imaging within a wide focal length range. This design helps to reduce optical distortion, chromatic aberration, and blurring, and improves the clarity and color reproduction of the image.

[0149] In some examples of the present application, referring to Figure 13 and Figure 14 , the focal length of the first lens 1 is F1, 1 mm ≤ F1 ≤ 5 mm; the focal length of the second lens 2 is F2, -10 mm ≤ F2 ≤ -1 mm; and the focal length of the third lens 3 is F3, 15 mm ≤ F3 ≤ 350 mm.

[0150] According to the above example, the focal length F1 of the first lens 1 is in the range of 1 mm to 5 mm, which is a relatively short focal length range. The focal length F2 of the second lens 2 is in the range of -10 mm to -1 mm, indicating that it is a negative focal length lens (concave lens). Negative focal length lenses are often used to correct aberrations, expand the field of view, or reduce the focal length of the system. The focal length F3 of the third lens 3 is in the range of 15 mm to 350 mm, which is a relatively large focal length range. In this way, the combined focal length F 123 of the three lenses can be in the above range of 5 mm to 15 mm.

[0151] The different focal length combinations of the three lenses make the AR light machine highly flexible in optical design. Combined with positive and negative focal length lenses, the focal length of the system can be shortened or lengthened, and the optical distortion can be corrected.

[0152] Through the precise combination of three lenses and the optimization of focal length, the optical projection system can achieve high-quality imaging within a wide range of focal lengths. The combination of positive and negative focal length lenses helps to correct system aberrations and chromatic aberrations, improving image clarity and color restoration.

[0153] In some examples of the present application, referring to Figure 8 and Figure 14 , the first lens 1 sets the radius of curvature of the surface of the superposition element to R1, R1>20mm.

[0154] It is worth noting that when the second lens 2 and / or the third lens 3 are introduced into the AR light machine, there are higher requirements for the radius of curvature R1 of the first lens 1. Specifically, the radius of curvature R1 of the first lens 1 is greater than 20mm. This adjustment is mainly based on the allocation of optical power.

[0155] Referring to Figure 8 and Figure 14 two examples, by allocating optical power to the second lens 2 and / or the third lens 3, the layout and performance of the optical path can be further optimized.

[0156] Specifically, a larger R1 value means that the surface curvature of the first lens 1 is smaller, which helps to reduce its optical power, thereby allocating more optical power to the subsequent second lens 2 and / or third lens 3. Such allocation helps to reduce the optical distortion of a single lens, ultimately helping to improve the imaging quality of the optical projection system.

[0157] This example of the present application shows that by introducing the second lens 2 and the third lens 3, and adjusting the radius of curvature R1 of the first lens 1, the layout of the optical path is optimized, so that the light rays are more effectively controlled and optimized within the AR light machine.

[0158] The coordinated work of multiple lenses enhances the resistance of the AR light machine to external interference, improving the stability and reliability of the system. Despite the introduction of more lenses, through fine adjustment and optimization of the parameters of each lens, the miniaturization design of the optical projection system is still maintained.

[0159] In some examples of the present application, referring to Figure 2 , Figure 8 and Figure 14 , the total optical length of the AR light machine is L, 1mm≤L≤6mm.

[0160] The AR optical machine provided by the embodiments of the present application has a relatively short total optical length, which greatly promotes the miniaturization of the optical projection system. In the AR optical device, miniaturization is a key factor because it directly affects the portability of the device and the wearing comfort of the user. A shorter total optical length means that the optical projection system can be more easily integrated into various AR devices.

[0161] Considering that the shortest length of the non-folding optical path design on the current market has reached 5.6 mm for a single green optical machine, and about 8 mm for color, the optical projection system design in the present application has made significant progress in the total optical length.

[0162] The present application can still achieve miniaturization while ensuring imaging quality through precise optical design and lens combination. This means that the optical projection system can achieve miniaturization and portability without sacrificing image clarity, color restoration, or other imaging performance indicators.

[0163] With the continuous development of AR technology and the increasing maturity of the market, the demand for miniaturized and high-performance optical projection systems will continue to increase. The optical projection system design in the present application exactly meets this market demand and has broad market prospects and application potential.

[0164] In addition, the optical projection system provided by the embodiments of the present application, as shown in Figure 1 , Figure 7 and Figure 13 , the polarization reflection element 5 is arranged at the leftmost side of the optical projection system, i.e., the front end of the optical projection system. Based on this, it can be considered that the distance from the polarization reflection element 5 to the light-emitting surface of the screen 4 is approximately the total optical length, i.e., 1-6 mm.

[0165] The position of the polarization reflection element 5 in the optical path ensures that it can effectively manage the polarization of light. This is crucial for ensuring image quality and color accuracy. The position and function of the polarization reflection element 5 also help to reduce stray light. In the optical projection system, stray light can reduce the contrast and clarity of the image. By placing the polarization reflection element 5 at the front end of the optical path, it can effectively reflect and filter out unwanted light, thereby improving the imaging quality.

[0166] In some examples of the present application, the distance from the polarization reflection element 5 to the exit pupil position of the AR optical machine is PD, and 0≤PD≤10 mm.

[0167] The AR optical machine needs to be used together with a light guiding device such as a light waveguide sheet 12.

[0168] When PD is 0 mm, it means that the exit pupil position of the AR light engine and the entrance pupil position of the optical waveguide sheet 12 are completely coincident. This close fit can ensure that light rays enter the optical waveguide directly and efficiently from the optical projection system, reducing light energy loss and improving imaging brightness and quality.

[0169] When PD is greater than 0 mm, it means that there is a certain distance between the exit pupil position of the AR light engine and the entrance pupil position of the optical waveguide sheet 12. This reserved distance can provide more fault tolerance space for the assembly between the AR light engine and the optical waveguide sheet 12, facilitating accurate adjustment and calibration, and ensuring that the light output by the AR light engine can accurately enter the optical waveguide.

[0170] AR optical devices such as AR glasses need to consider the comfort and portability of users, so their appearance design should be relatively compact. Limiting the PD to within 10 mm is beneficial for the design of the bend of the temple of the AR glasses. This design ensures that the overall appearance of the AR glasses meets the ergonomic requirements and can accommodate key components such as the optical projection system and the optical waveguide.

[0171] A suitable PD range can ensure that light rays maintain high quality during transmission. Too long or too short PD can cause light loss, increased aberration, and other problems, affecting the final imaging effect. Therefore, limiting the PD to the range of 0 mm to 10 mm helps to maintain the stability and consistency of imaging quality.

[0172] By optimizing the cooperation between the AR light engine and the optical waveguide sheet 12 and the appearance design of the AR glasses, the optical projection system in the examples of the present application can provide users with a more comfortable and natural AR experience. At the same time, due to the improvement of imaging quality and the increase of light energy utilization, users can obtain clearer and brighter virtual images when using AR glasses.

[0173] In some examples of the present application, the focal length of the AR light engine is F, and 2.5 mm ≤ F ≤ 10 mm.

[0174] Focal length is a key parameter in optical systems, which determines the magnification and viewing angle of imaging.

[0175] By reasonably designing the total focal length of the AR light engine, the optical projection system can adapt to different imaging needs, thereby providing flexible viewing angles and imaging ranges. A shorter total focal length (such as 2.5 mm) allows the optical projection system to work at a shorter working distance, while a longer total focal length (such as 10 mm) can provide clear imaging at a longer working distance. Therefore, a focal length range of 2.5 mm to 10 mm can adapt to the needs of different working distances.

[0176] The optical projection system can provide better imaging clarity, contrast and color accuracy at appropriate working distance and focal length. By carefully designing the focal length range, the optical projection system can ensure high-quality imaging effects in different application scenarios.

[0177] In addition, when the AR light machine has a shorter focal length, it helps to reduce the overall size of the optical projection system, making it more compact. This is very important for AR optical devices such as AR glasses, as they usually need to consider the comfort and portability of the user. A shorter focal length can make the optical projection system easier to integrate into these optical devices while maintaining a small volume and weight.

[0178] In some examples of the present application, see Figure 2 , Figure 6 and Figure 12 , the field of view FOV of the AR light machine is 20°-50°.

[0179] The size of the field of view directly affects the immersion and realism of the user in the virtual environment. Too small a field of view may make the user feel limited in a narrow field of view, while too large a field of view may cause image distortion or eye fatigue. The field of view range of 20° to 50° is able to provide a more comfortable and natural user experience.

[0180] The field of view range of 20° to 50° can adapt to different application scenarios. For example, in games that require high immersion, a larger field of view can provide a wider field of view; while in some applications that require fine operation, a smaller field of view may be more suitable.

[0181] The optical projection system provided in the present application is specifically described below by way of Examples 1 to 3.

[0182] Example 1

[0183] See Figure 1 and Figure 3 , the optical projection system comprises an AR light machine and an optical waveguide sheet 12; the AR light machine comprises a polarization reflection element 5, a first phase retarder 6, a first lens 1, a first light splitting element 7, a second phase retarder 8, a polarization element 9, a protective glass 10 and a screen 4 arranged in sequence along the same optical axis;

[0184] Wherein, the polarization reflection element 5 and the first phase retarder 6 are stacked to form a superposition element, the superposition element is arranged on the first surface 101 of the first lens 1, and the curvature radius of the first surface 101 of the first lens 1 is R1, R1>15mm;

[0185] Wherein, the light splitting element 7 is arranged on the light output surface of the screen 4;

[0186] The light exit surface of the screen 4 is further provided with a second phase retarder 8 and a polarizing element 9, which are used to convert the light emitted by the screen 4 into circularly polarized light; the light splitting element 7 is arranged on the side of the second phase retarder 8 away from the polarizing element 9, and the light splitting element 7, the second phase retarder 8 and the polarizing element 9 form a composite film material;

[0187] The protective glass 10 is arranged between the composite film material and the light exit surface of the screen 4;

[0188] The distance between the exit pupil position of the AR light machine and the entrance pupil position of the light waveguide sheet 12 is 3.3 mm;

[0189] The distance PD between the polarizing reflection element 5 and the exit pupil position of the AR light machine is 0.02 mm;

[0190] The total optical length L of the AR light machine is 4.09 mm;

[0191] The FOV of the AR light machine is 30°.

[0192] Table 1 shows the specific optical parameters of the optical projection system of the present embodiment.

[0193] Table 1

[0194]

[0195]

[0196]

[0197] Referring to Figure 1 and Figure 3 , the light emitting path of the optical projection system is from right to left:

[0198] Screen 4 emits naturally circularly polarized light → After passing through polarization element 9, S-light is transmitted (P-light is absorbed) → After passing through the second phase delayer 8, it becomes circularly polarized light → After passing through beam splitter 7 (beam splitting film, 50% transmission, 50% reflection), the circularly polarized light is transmitted (in addition, the reflected circularly polarized light passes through the second phase delayer 8 to become P-light, and then passes through polarization element 9 to be absorbed) → First, it passes through the first lens 1 to correct aberrations → After passing through the first phase delayer 6, it becomes P-light → The P-light reaches the polarization reflection element 5 (reflecting P-light and transmitting S-light) and is reflected → The P-light passes through the first phase delayer to become circularly polarized light → Second, it passes through the first lens 1 to correct aberrations → After passing through beam splitter 7, 50% of the light is reflected → Third, it passes through the first lens 1 to correct aberrations → After passing through the first phase delayer 6, the circularly polarized light becomes S-light → The S-light passes through the polarization reflection element 5 → It is emitted to the optical waveguide 12 and finally forms an image in the human eye 01.

[0199] The optical projection system provided in Embodiment 1 has the following optical performance: Figures 4 to 7 As shown:

[0200] Figure 4 This is the MTF diagram of the optical projection system shown in Embodiment 1. The average MTF of each field of view is >0.49@125lp / mm, indicating excellent imaging performance.

[0201] Figure 5 This is a dot plot of the optical projection system shown in Embodiment 1. The RMS value of each field of view is much smaller than 1 pixel, resulting in excellent imaging effect.

[0202] Figure 6 This is the optical distortion diagram of the optical projection system shown in Embodiment 1. The optical distortion is <0.8%, which meets the viewing level of the human eye.

[0203] Figure 7 This is the relative illuminance diagram of the optical projection system shown in Embodiment 1. The relative illuminance is >76%, which meets the conventional requirements for optical engine brightness and uniformity.

[0204] Example 2

[0205] See Figure 1 and Figure 9 The optical projection system includes an AR optical engine and an optical waveguide 12; the AR optical engine includes a polarization reflection element 5, a first phase retarder 6, a first lens 1, a second lens 2, a first beam splitter 7, a second phase retarder 8, a polarization element 9, a protective glass 10, and a screen 4 arranged sequentially along the same optical axis; wherein the first lens 1 and the second lens 2 form a lens group 13.

[0206] The polarization reflection element 5 and the first phase retarder 6 are stacked to form a combined element, which is arranged on the first surface 101 of the first lens 1, the first surface 101 of the first lens 1 has a radius of curvature R1, and R1>20mm;

[0207] The light splitting element 7 is arranged on the light exit surface of the screen 4.

[0208] The light exit surface of the screen 4 is further stacked with a second phase retarder 8 and a polarization element 9, the second phase retarder 8 and the polarization element 9 are used to convert the light emitted by the screen 4 into circularly polarized light; the light splitting element 7 is stacked on the side of the second phase retarder 8 away from the polarization element 9, and the light splitting element 7, the second phase retarder 8 and the polarization element 9 form a composite film material.

[0209] The protective glass 10 is located between the composite film material and the light exit surface of the screen 4.

[0210] The distance between the exit pupil position of the AR light machine and the entrance pupil position of the light waveguide sheet 12 is 3.3mm.

[0211] The distance PD between the polarization reflection element 5 and the exit pupil position of the AR light machine is 0.02mm.

[0212] The total optical length L of the AR light machine is 3.53mm.

[0213] The FOV of the AR light machine is 30°.

[0214] Table 2 shows the specific optical parameters of the optical projection system of the present embodiment 2.

[0215] Table 2

[0216]

[0217]

[0218]

[0219]

[0220] Referring to Figure 1 and Figure 9 The light emitting path of the optical projection system is from right to left:

[0221] Screen 4 emits naturally circularly polarized light → After passing through polarization element 9, S-light is transmitted (P-light is absorbed) → After passing through the second phase delayer 8, it becomes circularly polarized light → After passing through beam splitter 7 (50% transmission, 50% reflection), the circularly polarized light is transmitted (in addition, the reflected circularly polarized light passes through the second phase delayer 8 to become P-light, and then after passing through polarization element 9, the P-light is absorbed) → It passes through the second lens 2 and the first lens 1 for the first time to eliminate aberrations → After passing through the first phase delayer 6, it becomes P-light → The P-light reaches the polarization reflection element 5 (reflects P-light and transmits S-light) and is reflected → The P-light passes through the first phase delayer 6 and becomes circularly polarized light → It passes through the first lens 1 and the second lens 2 for the second time to eliminate aberrations → After passing through beam splitter 7, 50% of the light is reflected → It passes through the second lens 2 and the first lens 1 for the third time to eliminate aberrations → After passing through the first phase delayer 6, the circularly polarized light becomes S-light → The S-light passes through the polarization reflection element 5 → It is emitted to the optical waveguide 12 and finally forms an image in the human eye 01.

[0222] The optical projection system provided in this embodiment 2 has the following optical performance: Figures 10 to 13 As shown:

[0223] Figure 10 This is the MTF diagram of the optical projection system shown in Embodiment 2. The average MTF of each field of view is >0.7@125lp / mm, and the imaging effect is excellent.

[0224] Figure 11 This is a dot plot of the optical projection system shown in Embodiment 2. The RMS value of each field of view is much smaller than 1 pixel, resulting in excellent imaging effect.

[0225] Figure 12 This is the optical distortion diagram of the optical projection system shown in Embodiment 2. The optical distortion is <2%, which meets the viewing level of the human eye.

[0226] Figure 13 This is the relative illuminance diagram of the optical projection system shown in Embodiment 2. The relative illuminance is >80%, which meets the conventional requirements for optical engine brightness and uniformity.

[0227] Example 3

[0228] See Figure 1 and Figure 15 The optical projection system includes an AR optical engine and an optical waveguide 12; the AR optical engine includes a polarization reflection element 5, a first phase retarder 6, a first lens 1, a second lens 2, a third lens 3, a first beam splitter 7, a second phase retarder 8, a polarization element 9, a protective glass 10, and a screen 4 arranged sequentially along the same optical axis; wherein the first lens 1, the second lens 2, and the third lens 3 form a lens group 13;

[0229] The polarization reflection element 5 and the first phase retarder 6 are stacked to form a combined element, which is arranged on the first surface 101 of the first lens 1, the first surface 101 of the first lens 1 has a radius of curvature R1, and R1>20mm;

[0230] The light splitting element 7 is arranged on the light exit surface of the screen 4.

[0231] The light exit surface of the screen 4 is further stacked with a second phase retarder 8 and a polarization element 9, the second phase retarder 8 and the polarization element 9 are used to convert the light emitted by the screen 4 into circularly polarized light; the light splitting element 7 is stacked on the side of the second phase retarder 8 away from the polarization element 9, and the light splitting element 7, the second phase retarder 8 and the polarization element 9 form a composite film material.

[0232] The protective glass 10 is located between the composite film material and the light exit surface of the screen 4.

[0233] The distance between the exit pupil position of the AR light machine and the entrance pupil position of the optical waveguide sheet 12 is 3.3mm.

[0234] The distance PD between the polarization reflection element 5 and the exit pupil position of the AR light machine is 0.02mm.

[0235] The total optical length L of the AR light machine is 3.25mm.

[0236] The FOV of the AR light machine is 30°.

[0237] Table 3 shows the specific optical parameters of the optical projection system of the present embodiment 3.

[0238] Table 3

[0239]

[0240]

[0241]

[0242]

[0243] Referring to Figure 1 and Figures 16 to 19 , the light emitting path of the optical projection system is from right to left:

[0244] Screen 4 emits natural circularly polarized light → S light transmits (P light is absorbed) after passing through polarizing element 9 → circularly polarized light after passing through second phase retarder 8 → circularly polarized light transmits after passing through light splitting element 7 (50% transmits, 50% reflects) (in addition, the reflected part of the circularly polarized light passes through second phase retarder 8 to become P light, and then the P light is absorbed after passing through polarizing element 9) → aberration is eliminated for the first time after passing through third lens 3, second lens 2 and first lens 1 → P light becomes S light after passing through first phase retarder 6 → P light is reflected after passing through polarizing reflecting element 5 (anti-P light and S light transmits) → circularly polarized light after passing through first phase retarder 6 → aberration is eliminated for the second time after passing through first lens 1, second lens 2 and third lens 3 → 50% light is reflected after passing through light splitting element 7 → aberration is eliminated for the third time after passing through third lens 3, second lens 2 and first lens 1 → circularly polarized light becomes S light after passing through first phase retarder 6 → S light transmits through polarizing reflecting element 5 → exits to optical waveguide sheet 12, and finally forms an image in human eye 01.

[0245] The optical projection system provided in this embodiment 3 has the optical performance as shown in the following table: Figure 16

[0246] Figure 17 FIG. 7 is an MTF diagram of the optical projection system shown in this embodiment 3, and the average MTF of each field of view is greater than 0.7@125lp / mm, and the imaging effect is extremely good.

[0247] Figure 18 FIG. 8 is a spot diagram of the optical projection system shown in this embodiment 3, and the RMS value of each field of view is much smaller than 1 pixel size, and the imaging effect is extremely good.

[0248] Figure 19 FIG. 9 is an optical distortion diagram of the optical projection system shown in this embodiment 3, and the optical distortion is less than 1.3%, which meets the horizontal viewing requirement of the human eye.

[0249] ​ FIG. 10 is a relative luminance diagram of the optical projection system shown in this embodiment 3, and the relative luminance is greater than 92%, which meets the conventional requirements of light machine brightness and uniformity.

[0250] According to yet another embodiment of the present application, an AR optical device is provided, which includes the optical projection system as described above.

[0251] It should be noted that the AR optical device provided in the embodiments of the present application is, for example, an AR head-mounted display device. Further, the AR head-mounted display device is, for example, AR smart glasses or an AR smart helmet, etc.

[0252] ​The specific implementation of the AR optical device of the embodiments of the present application can refer to the above-mentioned optical projection system embodiments, and thus has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0253] The focus of the above embodiments is to describe the differences between the various embodiments. The different optimization features between the various embodiments can be combined to form a better embodiment as long as they are not contradictory. Considering the brevity of the writing, it will not be repeated here.

[0254] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An optical projection system, characterized in that, Including AR optical engines; The AR optical engine includes a polarization reflection element (5), a first phase retarder (6), and a beam splitter (7) arranged along the same optical axis, and the first phase retarder (6) is located between the polarization reflection element (5) and the beam splitter (7); The optical projection system further includes a first lens (1), which is located between the first phase retarder (6) and the beam splitter (7). The polarization reflection element (5) is stacked with the first phase retarder (6) to form a superimposed element, and the superimposed element is disposed on the side surface of the first lens (1) away from the beam splitter (7). The first lens (1) is configured with a surface curvature radius of R1, where R1 > 15 mm; The AR optical engine includes a screen (4), which is disposed along the optical axis on the side of the beam splitter (7) away from the first phase delayer (6); The beam splitter (7) is disposed on the light-emitting surface of the screen (4); Along the optical axis, the distance from the beam splitter (7) to the light-emitting surface of the screen (4) is L1, 0.1mm≤L1≤1.5mm.

2. The optical projection system according to claim 1, characterized in that, The optical projection system includes an optical waveguide (12), which is used to propagate the projection light emitted from the AR optical engine to the target position for imaging; The distance between the exit pupil position of the AR optical engine and the entrance pupil position of the optical waveguide (12) is 2mm to 5mm.

3. The optical projection system according to claim 1, characterized in that, The image height of the screen (4) is H, where 0 < H ≤ 7.7 mm.

4. The optical projection system according to claim 1, characterized in that, The light-emitting surface of the screen (4) is provided with a second phase delayer (8) and a polarizing element (9). The second phase delayer (8) and the polarizing element (9) are used to convert the light emitted from the screen (4) into circularly polarized light. The beam splitter (7) is stacked on the side of the second phase delayer (8) away from the polarization element (9), and the beam splitter (7), the second phase delayer (8) and the polarization element (9) constitute a composite film.

5. The optical projection system according to claim 4, characterized in that, A protective glass (10) is provided on the light-emitting surface of the screen (4), and the protective glass (10) is located between the composite film and the light-emitting surface of the screen (4).

6. The optical projection system according to claim 1, characterized in that, The screen (4) and the first lens (1) are arranged adjacent to each other, and the air gap between the screen (4) and the first lens (1) is ≥0.1mm; The focal length of the first lens (1) is F1, 5mm≤F1≤20mm.

7. The optical projection system according to claim 1, characterized in that, The AR optical engine also includes a second lens (2), which is located between the first lens (1) and the screen (4). The screen (4) and the second lens (2) are arranged adjacent to each other, and the air gap between the screen (4) and the second lens (2) is ≥0.1mm. The combined focal length of the first lens (1) and the second lens (2) is F. 12 5mm≤F 12 ≤20mm.

8. The optical projection system according to claim 7, characterized in that, The focal length of the first lens (1) is F1, 2mm≤F1≤10mm; The focal length of the second lens (2) is F2, 20mm≤F2≤50mm.

9. The optical projection system according to claim 1, characterized in that, The AR optical engine also includes a second lens (2) and a third lens (3). The screen (4) and the third lens (3) are arranged adjacent to each other, and the second lens (2) is located between the first lens (1) and the third lens (3). The air gap between the screen (4) and the third lens (3) is ≥0.1mm. The combined focal length of the first lens (1), the second lens (2), and the third lens (3) is F. 123 5mm≤F 123 ≤15mm.

10. The optical projection system according to claim 9, characterized in that, The focal length of the first lens (1) is F1, 1mm≤F1≤5mm; The focal length of the second lens (2) is F2, -10mm≤F2≤-1mm; The focal length of the third lens (3) is F3, 15mm≤F3≤350mm.

11. The optical projection system according to any one of claims 7-9, characterized in that, The first lens (1) is configured with a surface curvature radius of R1, where R1 > 20 mm.

12. The optical projection system according to any one of claims 1-10, characterized in that, The total optical length of the AR optical engine is L, where 1mm ≤ L ≤ 6mm.

13. The optical projection system according to any one of claims 1-10, characterized in that, The distance from the polarization reflection element (5) to the exit pupil of the AR optical engine is PD, where 0 ≤ PD ≤ 10 mm.

14. The optical projection system according to any one of claims 1-10, characterized in that, The total focal length of the AR optical engine is F, where 2.5mm ≤ F ≤ 10mm.

15. An AR optical device, characterized in that, include: The optical projection system as described in any one of claims 1-14.

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