Optical-mechanical lens module and ar optical display device

Abstract

Embodiments of the present application provide an optical-mechanical lens module and an AR optical display device; wherein the optical-mechanical lens module comprises, in order from the object side to the image side along the optical axis: a first lens, a second lens, a third lens, a fourth lens, an X-cube color combiner prism, and a fifth lens; the first lens is a non-spherical positive lens, the second lens is a non-spherical positive lens, the third lens is a non-spherical negative lens, the fourth lens is a non-spherical positive lens, and the fifth lens is a non-spherical negative lens; the total focal length F of the optical-mechanical lens module satisfies 4.1mmF<4.8mm; the focal length f1 of the first lens and the total focal length F satisfy 2.3f1 / F≤2.9; and the focal length f2 of the second lens and the total focal length F satisfy 2.1f2 / F≤2.4.

Description

Technical Field

[0001] This application relates to the field of projection optical display technology, and more specifically, to an optical engine lens module and an AR optical display device. Background Technology

[0002] With the advancement of optical technology, augmented reality (AR) technology has been widely used in the field of smart wearable devices. Its core component—the optical engine lens module (i.e., the light engine part)—has also undergone significant technological iterations, from DLP optical engine to LCOS optical engine to single green u-LED optical engine.

[0003] Full-color u-LED optical engines are widely recognized as the core direction of next-generation technology development, but their optical system design faces challenges: achieving a breakthrough in large field of view (FOV) while maintaining a compact size.

[0004] Currently, full-color u-LED optical engines generally employ a technology path of combining three RGB monochrome panels through an X-cube. However, this optical design is limited by existing optical architecture, resulting in a relatively large overall optical length and a maximum field of view that is difficult to exceed 65°. This contradiction between size and field of view (FOV) limits the wearing comfort of AR optical display devices and restricts the improvement of user immersion, becoming a key factor hindering the expansion of AR technology into wider application scenarios. Therefore, how to optimize the design of the optical engine lens module while ensuring optical performance, achieving a balance between small size and large field of view, has become a core issue that urgently needs to be addressed in the development of AR technology. Summary of the Invention

[0005] The purpose of this application is to provide a new technical solution for an optical engine lens module and an AR optical display device, which aims to achieve a balance between a large field of view, high image quality and a compact structure.

[0006] In a first aspect, embodiments of this application provide an optical-mechanical lens module, which comprises, along the optical axis from the object side to the image side, the following components in sequence:

[0007] The first lens is an aspherical positive lens;

[0008] The second lens is an aspherical positive lens;

[0009] The third lens is an aspherical negative lens;

[0010] The fourth lens is an aspherical positive lens;

[0011] X-cube color-combining prism; and

[0012] The fifth lens is an aspherical negative lens;

[0013] The total focal length F of the optical engine lens module is 4.1mm < F < 4.8mm;

[0014] The focal length f1 of the first lens and the total focal length F satisfy: 2.3 ≤ f1 / F ≤ 2.9;

[0015] The focal length f2 of the second lens and the total focal length F satisfy: 2.1≤f2 / F≤2.4.

[0016] Optionally, the fifth lens is a field lens, and its object side is an aspherical surface with a central concave shape;

[0017] And it meets the following air gap constraints:

[0018] The distance A1 between the center point of the object side surface of the fifth lens and the light-emitting surface of the X-cube color-combining prism is 0.3mm≤A1≤0.35mm;

[0019] The distance A2 between the object side surface of the fifth lens at 0.45mm and the light-emitting surface of the X-cube color-combining prism is 0.28mm≤A2≤0.32mm;

[0020] The distance A3 between the maximum aperture of the object side of the fifth lens and the light-emitting surface of the X-cube color-combining prism is 0.5mm ≤ A3 ≤ 0.6mm.

[0021] Optionally, the object side of the first lens has a sagitta of S1 at the maximum aperture and a sagitta of S2 at the maximum aperture, and the sagitta ratio is satisfied as follows: 2 < S2 / S1 < 2.3.

[0022] Optionally, the angle between the lens tangent at the maximum aperture of the first lens and the optical axis is A1, and the angle between the lens tangent at the maximum aperture of the first lens and the optical axis is A2, and the angle relationship is satisfied as follows: 1°<A1-A2<12°, and 0.9<A2 / A1<1.1.

[0023] Optionally, the object-side surface of the second lens has a sagitta of S3 at the maximum aperture, and the image-side surface has a sagitta of S4 at the maximum aperture, satisfying the sagitta ratio: 2.3 < S4 / S3 < 2.7.

[0024] Optionally, the angle between the lens tangent at the maximum aperture of the image side of the second lens and the optical axis is A3, and the angle between the lens tangent at the maximum aperture of the object side of the second lens and the optical axis is A4, and the angle relationship is satisfied: 20°<A3-A4<60°.

[0025] Optionally, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens satisfy: 2.6 < (T1 + T2 + T4) / (T3 + T5) < 3.2; where T1, T2, T3, T4, and T5 are the center thicknesses of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens, respectively.

[0026] Optionally, the ratio of the center thickness T4 of the fourth lens to the total optical length TTL of the optical-mechanical lens module is: 10%≤T4 / TTL≤13%;

[0027] The refractive index of the fourth lens is 1.8 to 1.9.

[0028] Optionally, the ratio of the center thickness T3 of the third lens to the total optical length TTL of the optical-mechanical lens module is: 3%≤T3 / TTL≤6%.

[0029] Optionally, the ratio of the total optical length TTL of the optical engine lens module to the maximum aperture D1 of the lens in the optical engine lens module satisfies: 11.3 < (TTL / D1) < 2.

[0030] Optionally, the optical-mechanical lens module further includes an aperture stop located on the object side of the first lens and a display unit located on the image side of the fifth lens;

[0031] The effective focal lengths of each lens in the optical-mechanical lens module are as follows:

[0032] The focal length of the first lens is f1, where 10.5mm ≤ f1 ≤ 12.5mm;

[0033] The focal length of the second lens is f2, 9.06mm≤f2≤11.06mm;

[0034] The focal length of the third lens is f3, -5.56mm≤f3≤-3.56mm;

[0035] The focal length of the fourth lens is f4, where 2.59mm ≤ f4 ≤ 4.59mm;

[0036] The focal length of the fifth lens is f5, -8.47mm≤f5≤-6.47mm;

[0037] The first lens, the second lens, the third lens, and the fifth lens are plastic lenses, and the fourth lens is a glass lens.

[0038] Optionally, the optical-mechanical lens module has a field of view (FOV) of 72.8°±0.5° when the working wavelength is 460nm~618nm.

[0039] Secondly, embodiments of this application provide an AR optical display device, the AR optical display device comprising:

[0040] As described in the first aspect, the optical engine lens module; and

[0041] An optical waveguide device, wherein the diameter of the aperture of the optical-mechanical lens module is matched with the entrance pupil diameter of the optical waveguide device.

[0042] The beneficial effects of this application are as follows:

[0043] The optical engine lens module provided in this application, through a unique lens combination design and in-depth optimization of optical parameters (especially lens focal length), achieves both effective control of module size and a large field of view (FOV up to 72.8°) while maintaining a compact overall system length (e.g., only 8.51mm). Compared to traditional optical engine solutions, this application significantly reduces the bulkiness of the device while expanding the field of view, thus improving user comfort and convenience.

[0044] In terms of optical performance, this application quantifies and constrains the focal length ratio of the first lens and the second lens (set within the range of 2.3≤f1 / F≤2.9 and 2.1≤f2 / F≤2.4) and adopts a "positive-positive-negative-positive-negative" optical power arrangement, so that the optical engine lens module has low optical distortion characteristics in the 460nm~618nm band, and the modulation transfer function (MTF) satisfies MTF>0.55@100lp / mm, effectively correcting aberrations, ensuring clear imaging, and greatly improving imaging quality.

[0045] In summary, the optical solution of this application embodiment balances the technical conflicts in terms of size, field of view and aberration control of the optical engine lens module, and provides optical technical support for the miniaturization and high performance development of AR optical display devices.

[0046] 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

[0047] 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.

[0048] Figure 1 This application provides a schematic diagram of the structure and optical path of an optical-mechanical lens module;

[0049] Figure 2 This is a partial structural schematic diagram of the first lens in the optical-mechanical lens module provided in this application;

[0050] Figure 3 This is a partial structural schematic diagram of the second lens in the optical-mechanical lens module provided in this application;

[0051] Figure 4 for Figure 1 The optical distortion diagram of the provided optical engine lens module;

[0052] Figure 5 for Figure 1 The modulation transfer function diagram of the provided optical-mechanical lens module;

[0053] Figure 6 This is a schematic diagram of the structure and optical path of the optical-mechanical lens module provided in Embodiment 1 of this application;

[0054] Figure 7 for Figure 6 The modulation transfer function diagram of the provided optical-mechanical lens module;

[0055] Figure 8 This is a schematic diagram of the structure and optical path of the optical-mechanical lens module provided in Embodiment 2 of this application;

[0056] Figure 9 for Figure 8 The modulation transfer function diagram of the provided optical-mechanical lens module;

[0057] Figure 10 This is a schematic diagram of the structure and optical path of the optical-mechanical lens module provided in Embodiment 3 of this application;

[0058] Figure 11 for Figure 10 The modulation transfer function diagram of the provided optical-mechanical lens module;

[0059] Figure 12 This is a schematic diagram of the structure and optical path of the optical-mechanical lens module provided in Embodiment 4 of this application;

[0060] Figure 13 for Figure 12 The provided modulation transfer function diagram for the optical-mechanical lens module.

[0061] Explanation of reference numerals in the attached figures:

[0062] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. X-cube color combining prism; 7. Display unit; 8. Aperture. Detailed Implementation

[0063] Various exemplary embodiments of the present 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 the present application.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] The optical engine lens module and AR optical display device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0069] According to one embodiment of this application, an optical-mechanical lens module is provided, see [link]. Figure 1 The optical system comprises, sequentially from the object side to the image side, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, an X-cube color-combining prism 6, and a fifth lens 5. The first lens 1 is an aspherical positive lens. The second lens 2 is an aspherical positive lens. The third lens 3 is an aspherical negative lens. The fourth lens 4 is an aspherical positive lens. The fifth lens 5 is an aspherical negative lens. The total focal length F of the optical-mechanical lens module is 4.1 mm < F < 4.8 mm. The focal length f1 of the first lens 1 satisfies the condition 2.3 ≤ f1 / F ≤ 2.9 with respect to the total focal length F. The focal length f2 of the second lens 2 satisfies the condition 2.1 ≤ f2 / F ≤ 2.4 with respect to the total focal length F.

[0070] The optical engine lens module provided in this application embodiment, with its unique optical design, has demonstrated excellent performance in the field of projection optical engines, and is especially suitable for applications such as augmented reality (AR).

[0071] The main components of the optical-mechanical lens module provided in the embodiments of this application are described below.

[0072] The optical-mechanical lens module provided in this embodiment is equipped with five lenses, which can be divided into two main lens groups according to their function and position:

[0073] See Figure 1The first lens group is located between the aperture stop 8 and the X-cube color combining prism 6. This first lens group mainly consists of a first lens 1 (an aspherical positive lens), a second lens 2 (an aspherical positive lens), a third lens 3 (an aspherical negative lens), and a fourth lens 4 (an aspherical positive lens) arranged sequentially along the same optical axis. This lens group is the key to achieving a large field of view (FOV) (72.8°) and high imaging quality.

[0074] See Figure 1 The second lens group is positioned between the X-cube color-combining prism 6 and the display unit 7. This second lens group may consist only of the fifth lens 5 (an aspherical negative lens), which is aligned along the same optical axis as the four lenses (first lens 1 to fourth lens 4) in the first lens group. In this application, the fifth lens 5 is a field lens. The fifth lens 5 can appropriately adjust the light propagation path and effectively correct field curvature, playing a crucial role in improving image edge sharpness and display effect.

[0075] In the design of the optomechanical projection lens in this application, see Figure 1 The first lens 1 is positioned close to the aperture stop 8 (front aperture stop) and is designed as an aspherical positive lens. It is responsible for collecting and converging the projected light, providing a highly compatible incident beam for subsequent optical devices (such as peripheral diffractive waveguide devices). Furthermore, the first lens 1 employs a large focal length optimization design, with its focal length f1 being 2.3 ≤ f1 / F ≤ 2.9 compared to the total focal length F of the entire optical-mechanical lens module. This design, while ensuring the compactness of the optical structure of the optical-mechanical lens module, helps to expand its field of view (FOV), enabling the optical-mechanical lens module to achieve an ultra-wide field of view of up to 72.8°. This feature breaks through the field of view limitations of traditional optical-mechanical solutions, providing optical technical support for creating an immersive visual experience for AR optical display devices, and is one of the core optical components ensuring high-performance imaging of the optical-mechanical lens module.

[0076] Following the first lens 1 (from the object side to the image side) is the second lens 2, which also employs an aspherical positive lens design. The second lens 2 not only converges light but also adjusts the light propagation path. It also possesses a large focal length characteristic, with the ratio of its focal length f2 to the total focal length F of the entire optical-mechanical lens module satisfying 2.1 ≤ f2 / F ≤ 2.4. The large focal length design of the second lens 2 and the first lens 1 work together to create an optical synergy effect, jointly constructing a "positive-positive" optical power combination. This design enhances the light-converging ability, and with the help of the aspherical surface, effectively controls aberrations such as spherical aberration and coma, playing a crucial role in maintaining image quality while achieving a large field of view.

[0077] On the side of the second lens 2 facing away from the first lens 1, a third lens 3 is arranged. The third lens 3 is designed as an aspherical negative lens. This negative lens, by controlling the degree of light divergence, forms an optical compensation mechanism with the positive lenses before and after it. Its negative optical power can balance the excessive convergence tendency produced by the positive lenses. It is worth mentioning that, through optimized design of the aspherical curvature of the third lens 3, optical distortion can be corrected during light divergence, controlling the optical distortion rate of the optical-mechanical lens module to a very small range, with optical distortion <15%. (See [reference needed]). Figure 4 .

[0078] Furthermore, a fourth lens 4, an aspherical positive lens, is disposed on the image side of the third lens 3 and is located close to the X-cube color-combining prism 6. The fourth lens 4 receives the color-combining light emitted from the X-cube color-combining prism 6, and then the color-combining light sequentially passes through the third lens 3, the second lens 2, and the first lens 1 before entering the aperture 8, and finally is projected onto an image by an external diffraction waveguide device. The third lens 3 and the fourth lens 4 cooperate to form an aberration cancellation mechanism. This design helps the optomechanical lens module of this application achieve high image quality output while maintaining a large field of view of 72.8°.

[0079] The first lens 1 to the fourth lens 4 in the optomechanical projection lens of this application, through their unique optical designs and mutual cooperation, achieve synergistic effects in multiple aspects, including light convergence, field of view expansion, aberration control, and high image quality output. These four lenses work together to enable the optomechanical lens module to maintain a large field of view of 72.8° while achieving high image quality output with an MTF value > 0.55@100lp / mm in the 460nm-618nm wavelength range. See [link to relevant documentation]. Figure 5 This high-quality output is not only reflected in the central area of ​​the image, but also improves the clarity and color reproduction of the display edge areas, providing excellent optical performance support for AR optical display devices and meeting the needs of miniaturization and high performance.

[0080] The optical-mechanical lens module provided in this application embodiment includes an X-cube color combining prism 6. The X-cube color combining prism 6, as a color combining element, plays an important role in the optical system of projection imaging, as specifically shown below:

[0081] (1) Accurate color matching to construct complete color information:

[0082] To present a rich variety of colors in projection imaging, the red (R), green (G), and blue (B) light from the display unit 7 must be combined in specific proportions and at precise positions. The X-cube color combining prism 6 can fuse the three primary colors of light, providing mixed light containing complete and accurate color information for the subsequent imaging process, thus laying the foundation for the brilliant colors of the projected image.

[0083] (2) Unify the optical path to ensure clear and accurate imaging:

[0084] During the color combining process, ensuring that the three colors of light maintain a unified optical path direction after merging is crucial. If the optical path deviates, it will lead to problems such as blurry projection and color misalignment, affecting the final visual effect. The X-cube color combining prism 6 possesses superior optical performance, precisely controlling the optical path of the three colors of light, ensuring that the combined light enters the subsequent lens group (i.e., the first lens 1 to the fourth lens 4) and other optical elements along a unified direction for further processing. This characteristic guarantees the clarity and accuracy of the projected image, allowing users to enjoy a high-quality visual experience.

[0085] (3) Compact and adaptable design, which helps to miniaturize the module:

[0086] While pursuing high performance, the miniaturization of optical-mechanical lens modules is also an important trend in current optical technology development. The X-cube color-combining prism 6 can be well adapted to the overall layout of the optical-mechanical lens module, working closely and collaboratively with optical components such as the front lens group (e.g., the first lens group includes the first lens 1 to the fourth lens 4) and the rear lens group (the second lens group includes the fifth lens 5). It completes the color-combining function within a limited and compact space, without occupying excessive space, while fully utilizing its color-combining effect. This compact and adaptable design helps achieve the goal of miniaturizing the optical-mechanical lens module, meeting the demands of modern optical equipment for portability and compactness.

[0087] In this application, the X-cube color combining prism 6 is used to combine light from different color channels (such as RGB) into a single light path, and is a core component for realizing full-color display. Its precise color combining function ensures accurate color reproduction and mixing, which is crucial for improving display effect.

[0088] In the design of the optomechanical projection lens in this application, see Figure 1The fifth lens 5 is located between the display unit 7 and the incident surface of the X-cube color-combining prism 6. The fifth lens 5 is an aspherical negative lens, whose negative optical power characteristics enable it to diverge the projected light rays emitted from the display unit 7. Since the light rays emitted from the display unit 7 may have limitations in angle and distribution during propagation, the fifth lens 5, through its aspherical design, controls the degree of light divergence, allowing the light rays to enter the X-cube color-combining prism 6 at a more suitable angle and with a more uniform distribution. This process provides favorable conditions for the subsequent merging of the three colors of light, ensuring that different colors of light can be accurately converged and mixed in the X-cube color-combining prism 6 according to design requirements.

[0089] The aspherical design endows the fifth lens 5 with aberration correction capabilities. In the optomechanical projection module, aberration is one of the important factors affecting image quality. With its aspherical surface design, the fifth lens 5 can correct various aberrations (such as field curvature) that may be caused by light emitted from the display unit 7.

[0090] While pursuing high performance, miniaturization and compact design of the optical-mechanical lens module are also design goals of this application. The rational layout and design of the fifth lens 5 helps to optimize the spatial structure of the entire optical system. Its aspherical shape can reduce the thickness and volume of the lens while ensuring optical performance, allowing the display unit 7, the fifth lens 5, and the X-cube color-combining prism 6 to be arranged more compactly, thereby achieving efficient optical functions within a limited space and meeting the design requirements for miniaturization of the optical-mechanical lens module.

[0091] The optical engine lens module provided in this application, through a unique lens combination design and in-depth optimization of optical parameters (especially lens focal length), achieves both effective control of module size and a large field of view (FOV up to 72.8°) while maintaining a compact overall system length (e.g., only 8.51mm). Compared to traditional optical engine solutions, this application significantly reduces the bulkiness of the device while expanding the FOV, thus improving user comfort and convenience.

[0092] In terms of optical performance, this application quantifies and constrains the focal length ratio of the first lens 1 and the second lens 2 (set within the range of 2.3≤f1 / F≤2.9 and 2.1≤f2 / F≤2.4), and adopts a "positive-positive-negative-positive-negative" optical power arrangement, so that the optical engine lens module has low optical distortion characteristics in the 460nm~618nm band, and the modulation transfer function MTF satisfies MTF>0.58@100lp / mm, effectively correcting aberrations, ensuring clear imaging, and greatly improving imaging quality.

[0093] In summary, the optical solution of this application embodiment balances the technical conflicts in terms of size, field of view and aberration control of the optical engine lens module, and provides optical technical support for the miniaturization and high performance development of AR optical display devices.

[0094] See some examples in this application. Figure 1 The fifth lens 5 is a field lens, and its object-side surface is an aspherical surface with a central concave shape; and it satisfies the following air gap constraint:

[0095] The distance A1 between the center point of the object side surface of the fifth lens 5 and the light-emitting surface of the X-cube color-combining prism 6 is 0.3mm≤A1≤0.35mm;

[0096] The distance A2 between the object side surface of the fifth lens 5 (0.45mm aperture) and the light-emitting surface of the X-cube color-combining prism 6 is 0.28mm ≤ A2 ≤ 0.32mm;

[0097] The distance A3 between the maximum aperture of the object side of the fifth lens 5 and the light-emitting surface of the X-cube color-combining prism 6 is 0.5mm ≤ A3 ≤ 0.6mm.

[0098] In the optical-mechanical lens module design of this application, the X-cube color combining prism 6 plays a key optical role. It can combine red, green and blue light to provide mixed light containing complete color information for the subsequent imaging process, which is crucial for achieving high-quality color display.

[0099] In the applied-for optical-mechanical lens module design, the fifth lens 5, serving as a field lens, is positioned between the display unit 7 and the X-cube color-combining prism 6. Its primary function is to process the projection light emitted from the display unit 7 and about to enter the X-cube color-combining prism 6. Field curvature is a common aberration that causes inconsistent image sharpness across different fields of view, affecting image quality. The fifth lens 5, through its unique optical properties, can effectively correct aberrations such as field curvature, enabling the processed projection light to be focused more accurately during subsequent imaging, thereby significantly improving the overall image quality of the optical-mechanical lens module.

[0100] In the example provided in this application, the air gaps between different positions on the object-side surface (near the aperture stop) of the fifth lens 5 and the incident surface of the X-cube color-combining prism 6 are constrained. From an optical principle perspective, the air gaps at different positions affect the incident propagation angle and optical path of light on the fifth lens 5. By controlling these air gaps, a constraint is effectively imposed on the surface shape of the object-side surface of the fifth lens 5. Under this constraint, the object-side surface of the fifth lens 5 will form a special W-shaped surface, see [reference needed]. Figure 1The fifth lens 5 shown has a concave center and convex sides. This surface shape can further optimize aberration correction, thereby bringing superior imaging performance to the entire optical engine lens module.

[0101] The air gap A1 between the center point of the object side of the fifth lens 5 and the light-emitting surface of the X-cube color-combining prism is constrained to the range of 0.3mm ≤ 1 ≤ 0.35mm. By controlling the size of A1, the surface shape of the central region of the fifth lens 5 can be controlled.

[0102] The air gap A2 between the object side of the fifth lens 5 (0.45mm aperture) and the incident surface of the X-cube color-combining prism 6 is constrained to the range of 0.28mm ≤ A2 ≤ 0.32mm. By setting an appropriate A2 value, the intermediate field-of-view rays can be guided to incident on the lens surface at the optimal angle. Based on this, combined with the overall surface design of the lens, especially the surface features of the 0.45mm aperture region, effective correction of intermediate field-of-view aberrations can be achieved, ensuring that the image in the intermediate region has high clarity and accurate color reproduction, allowing users to obtain a clear and realistic intermediate field-of-view image.

[0103] The air gap A3 between the maximum aperture (edge) of the fifth lens 5 and the incident surface of the X-cube color-combining prism 6 is limited to the range of 0.5mm ≤ A3 ≤ 0.6mm. In optical imaging, the light rays at the maximum aperture reflect the characteristics of the edge field of view rays, and their propagation path and imaging quality have a significant impact on the uniformity and integrity of the entire image.

[0104] By using the parameter constraints in this example, the quality of the edge image can be significantly improved, enabling the entire projected image to maintain a good imaging effect under different viewing fields, and achieving a high degree of uniformity and consistency of the image from the center to the edge.

[0105] Without field curvature correction, the edges of the projected image appear blurry because the light cannot be accurately focused. After the field curvature is corrected by the fifth lens 5 (as a field lens), the light from the edge field of view can be correctly focused on the image plane, greatly improving the sharpness of the image edges. This ensures that the entire projected image maintains a high level of sharpness from the center to the edges, providing users with a clearer and more realistic visual experience.

[0106] Field curvature not only affects image sharpness but can also cause inconsistent focusing positions of different colored light rays, resulting in color misalignment and deviation. The fifth lens 5 corrects field curvature, ensuring that red, green, and blue light rays, after being combined by the X-cube color combining prism 6, can accurately converge on the image plane, guaranteeing the consistency and accuracy of the projected image's colors and avoiding color distortion problems caused by field curvature.

[0107] For projection systems aiming for a large field of view, field curvature becomes even more severe. The presence of the fifth lens 5 ensures effective correction of light in different areas under a large field of view, expanding the range of clear imaging for the projection system. Even on large projection screens, users can see clear, distortion-free images from all positions, meeting the application requirements of large-scene projection.

[0108] The light emitted by the display unit 7 has certain angle and distribution characteristics. The fifth lens 5 can preprocess and adjust the light according to the output characteristics of the display unit 7. It can optimize the incident angle and distribution of the light, so that the light enters the subsequent optical system more evenly, providing good initial conditions for field curvature correction, and also helping to improve the light energy utilization rate of the entire system.

[0109] Before the light enters the X-cube color combining prism 6, the fifth lens 5 has already corrected the field curvature and adjusted the angle of the light. This makes the parameters of the light entering the X-cube color combining prism 6 more stable and accurate, which is beneficial for the precise beam combining of the three colors. At the same time, the light after field curvature correction can better maintain the consistency of the optical path during the color combining process, reducing the impact of optical path deviations caused by field curvature on the color combining effect, and further improving the quality of the projected image.

[0110] In the optomechanical projection lens module of this application, the fifth lens 5 works in conjunction with other lenses to achieve comprehensive aberration correction for the entire module by rationally allocating optical power and optimizing optical parameters. The fifth lens 5 is mainly responsible for correcting field curvature, while other lenses can correct other aberrations, thereby enabling the optomechanical lens module to achieve high imaging quality across the entire field of view.

[0111] See some examples in this application. Figure 1 The object side of the first lens 1 has a sagitta of S1 at the maximum aperture and a sagitta of S2 at the maximum aperture, and the sagitta ratio is satisfied as follows: 2 < S2 / S1 < 2.3.

[0112] Sag is an important optical parameter describing the shape of a lens surface. It reflects the height change of the lens surface relative to a reference plane at its maximum aperture.

[0113] In this application, the first lens 1 is a key optical element near the aperture stop 8 in the optical-mechanical lens module. The ratio of the height of its object side (the surface near the aperture stop 8, also known as the front surface) and image side (the surface away from the aperture stop 8, also known as the rear surface) has a direct impact on the propagation of light and the imaging quality.

[0114] When light passes through the first lens 1, the surface shape of the first lens 1 determines the refraction path of the light. Due to the different sag ratios of the object side and the image side, the refraction angle and focusing position of the light within the first lens 1 will change. By precisely controlling the ratio of S2 / S1 between 2 and 2.3, the propagation process of the light can be optimized, allowing the light to be more accurately focused onto subsequent optical elements (such as the aperture 8).

[0115] The first lens 1, which satisfies this sag-height ratio, enables light to be precisely focused onto a point such as the aperture stop 8 after refraction by the first lens 1, reducing light scattering and loss and improving light utilization. This helps to improve the imaging brightness of the optical engine lens module, making the projected image clearer and brighter.

[0116] A suitable sag-to-sag ratio can effectively correct aberrations generated by the first lens 1 itself, such as spherical aberration and coma. That is, by controlling the ratio of S2 / S1, the impact of these aberrations on image quality can be reduced, and the sharpness and contrast of the image can be improved.

[0117] The light rays emitted from the first lens 1 pass through the aperture 8 and are incident on the external diffractive optical device, ultimately forming a projection image. This sag-to-height ratio ensures that the angle and position of the light rays emitted from the first lens 1 match the requirements of the aperture and the diffractive optical device, allowing the light to pass smoothly through the subsequent optical system and achieve high-quality projection imaging. If the sag-to-height ratio is inappropriate, the light may be blocked at the aperture or fail to accurately enter the diffractive optical device, affecting the imaging effect.

[0118] See some examples in this application. Figure 2 The first lens 1 has an image-side tangent at its maximum aperture with an angle of A1 to the optical axis, and an object-side tangent at its maximum aperture with an angle of A2 to the optical axis, satisfying the following angular relationships: 1° < A1 - A2 < 12°, and 0.9 < A2 / A1 < 1.1.

[0119] The angle between the lens tangent and the optical axis reflects the degree of tilt of the lens surface at its maximum aperture.

[0120] When light passes through the first lens, changes in the incident and exit angles affect the propagation of the light in subsequent optical systems. By precisely controlling the difference and ratio between A1 and A2, the propagation direction of the light can be optimized, allowing the light to better adapt to the optical characteristics of subsequent optical components.

[0121] The angular relationship between A1 and A2 provided in this example, namely 1° < A1 - A2 < 12° and 0.9 < A2 / A1 < 1.1, enables precise control over the propagation direction of the light rays emitted from the first lens 1 relative to the optical axis. This helps ensure that the light rays can pass smoothly through the aperture 8 and accurately enter the diffractive optical device of the peripheral. If the angular relationship between A1 and A2 is not appropriate, the light rays may be deflected at the aperture 8 or fail to accurately enter the diffractive optical device, resulting in blurred or distorted images.

[0122] A suitable angular relationship can also reduce aberrations caused by improper incident and exit angles of light in the first lens 1. For example, when the angular difference is too large or the ratio is unreasonable, it may cause large aberrations and affect image quality. By precisely controlling A1 and A2, the generation of these aberrations can be effectively suppressed, improving the sharpness and uniformity of the image.

[0123] In this application, for the first lens 1, which is located near the aperture stop 8 and has an aspherical positive optical power, the sagitta S1 of its object-side surface at the maximum aperture and the sagitta S2 of its image-side surface at the maximum aperture are set to satisfy 2 < S2 / S1 < 2.3. The angle A1 between the lens tangent and the optical axis at the maximum aperture of the image-side surface and the angle A2 between the lens tangent and the optical axis at the maximum aperture of the object-side surface satisfy 1° < A1-A2 < 12° and 0.9 < A2 / A1 < 1.1. This design allows the first lens 1 to precisely control the propagation of light. A suitable sagitta ratio can optimize light focusing, effectively correct aberrations, and improve image clarity and contrast; a reasonable angular relationship can precisely control the direction of light propagation, reduce aberrations caused by improper angles, ensure that light passes smoothly through the aperture stop and accurately enters the subsequent diffractive optical devices, improve the stability and reliability of the module, and ensure high-quality imaging of the projected image.

[0124] See some examples in this application. Figure 1 The object side of the second lens 2 has a sagitta of S3 at the maximum aperture, and the image side has a sagitta of S4 at the maximum aperture, and the sagitta ratio is satisfied: 2.3 < S4 / S3 < 2.7.

[0125] In the example provided in this application, for the second lens 2 located on the side of the first lens 1 away from the aperture 8, the sagitta of its object side at the maximum aperture is set to S3, and the sagitta of its image side at the maximum aperture is set to S4, and the sagitta ratio relationship of 2.3 < S4 / S3 < 2.7 is satisfied.

[0126] As a key optical component in the optomechanical lens module, the second lens 2's height ratio between its object-side and image-side surfaces plays a crucial role in light propagation and image quality. Height reflects the change in the lens surface's height relative to the reference plane at its maximum aperture; different height ratios alter the refraction path and focusing of light within the lens. Appropriate height ratio control allows light to refract in the desired manner when incident on the second lens 2, thus better matching it with subsequent optical components.

[0127] The second lens 2, which satisfies the sag-height ratio in this example of the application, enables the incident light rays to more accurately adjust their propagation direction after passing through the second lens 2, preparing them for subsequent passage through the first lens 1, the aperture 8, and into the diffractive optical device of the peripheral device. This helps reduce light scattering and loss during propagation, improves light utilization, and allows more light rays to participate in the final projection imaging, thereby enhancing the brightness of the image.

[0128] A suitable sag ratio can also effectively correct aberrations generated by the second lens 2 itself. By controlling the S4 / S3 ratio between 2.3 and 2.7, the impact of these aberrations on image quality can be reduced, improving image sharpness and uniformity.

[0129] The light rays emitted from the second lens 2 pass through the first lens 1 and enter the aperture 8, then are incident on the external diffractive optical device via the aperture 8. This sag-to-height ratio ensures that the angle and position of the light rays emitted from the second lens 2 match the requirements of the first lens 1, the aperture 8, and the diffractive optical device, allowing the light to pass smoothly through the optical system and achieve high-quality projection imaging. If the sag-to-height ratio is inappropriate, it may cause abnormalities in the light rays at the first lens 1 or the aperture 8, affecting the final imaging effect.

[0130] See some examples in this application. Figure 3 The angle between the lens tangent at the maximum aperture of the image side of the second lens 2 and the optical axis is A3, and the angle between the lens tangent at the maximum aperture of the object side of the second lens 2 and the optical axis is A4, and the angle relationship is satisfied: 20°<A3-A4<60°.

[0131] The angle between the lens tangent and the optical axis reflects the tilt of the lens surface at its maximum aperture. The angular relationship between the object-side and image-side tangents of the second lens 2 and the optical axis determines the incident and exit angles of light rays on the surface of the second lens 2. When light rays pass through the second lens 2, a suitable angular relationship allows the light rays to propagate along an ideal path, enabling better integration with subsequent optical elements.

[0132] By satisfying the angular relationship of 20° < A3 - A4 < 60°, the propagation direction of the light rays emitted from the second lens 2 relative to the optical axis can be controlled. This helps ensure that the light rays, after passing through the first lens 1 and the aperture 8, can accurately enter the external diffractive optical device. If the angular relationship is not appropriate, the light rays may be deflected at the first lens 1 or the aperture 8, resulting in inaccurate entry into the diffractive optical device, thereby affecting the image quality.

[0133] A suitable angular relationship can reduce aberrations caused by improper incident and exit angles of light in the second lens 2. By precisely controlling the difference between A3 and A4, these aberrations can be effectively suppressed, improving image quality.

[0134] The second lens 2, by meeting the design requirements of a sag-to-height ratio of 2.3 < S4 / S3 < 2.7 at the maximum aperture of the object-side and image-side surfaces, and a difference of 20° < A3-A4 < 60° between the lens tangent and optical axis at the maximum aperture of the image-side and object-side surfaces, can precisely control light propagation. A suitable sag-to-height ratio optimizes the light propagation path, corrects aberrations, and coordinates with the preceding and following optical elements; a reasonable angular relationship precisely controls the direction of light propagation, reduces aberrations, and enhances system adaptability. These design features collectively ensure that the light emitted from the second lens 2 can smoothly pass through the first lens 1 and the aperture stop 8 into the diffractive optical device, ultimately achieving high-quality projection imaging and improving the performance and stability of the optomechanical lens module.

[0135] In some examples of this application, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4 and the fifth lens 5 satisfy: 2.6 < (T1 + T2 + T4) / (T3 + T5) < 3.2; where T1, T2, T3, T4 and T5 are the center thicknesses of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4 and the fifth lens 5, respectively.

[0136] In the design of the optical-mechanical lens module of this application, specific requirements are put forward for the center thickness of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4 and the fifth lens 5, namely, satisfying the relationship 2.6 < (T1 + T2 + T4) / (T3 + T5) < 3.2, wherein the first lens 1, the second lens 2 and the fourth lens 4 are positive lenses, and the third lens 3 and the fifth lens 5 are negative lenses.

[0137] From the perspective of the overall optical design of the optical-mechanical lens module, the center thickness of the lens is one of the key optical parameters affecting light propagation and image quality. Different lenses perform different optical functions, and the rational distribution of their center thickness is crucial for optimizing the performance of the entire optical-mechanical lens module. This relationship ensures the balance of the optical structure and the coordination of optical performance of the optical-mechanical lens module by limiting the combination and proportion of the center thickness of each lens.

[0138] A suitable lens thickness ratio helps to effectively correct various aberrations in the optical-mechanical lens module. In the optical-mechanical lens module, the presence of aberrations affects image quality, such as spherical aberration, coma, astigmatism, and field curvature. Lenses of different thicknesses have different aberration correction capabilities. By controlling the ratio of (T1+T2+T4) / (T3+T5) between 2.6 and 3.2, the positive and negative lenses can work synergistically to correct aberrations, thereby significantly improving image sharpness and contrast, resulting in a more realistic and accurate projected image.

[0139] This thickness ratio helps maintain the compactness and stability of the optical-mechanical lens module while meeting optical performance requirements. Furthermore, by controlling the thickness ratio at the center of each lens, light can be distributed more evenly across the entire image plane, thereby improving the uniformity of image quality. Within the optical-mechanical lens module, the image quality in different areas of the image plane may vary due to differences in light propagation. A reasonable lens thickness ratio can adjust the focusing of light at different locations on the image plane, reducing the difference in image quality between the edges and the center, resulting in consistent sharpness and color reproduction throughout the projected image, providing users with a superior visual experience.

[0140] In some examples of this application, the ratio of the center thickness T4 of the fourth lens 4 to the total optical length TTL of the optical-mechanical lens module is: 10%≤T4 / TTL≤13%. The refractive index of the fourth lens 4 is 1.8~1.9.

[0141] In the design of the optical-mechanical lens module of this application, two key parameter requirements are proposed for the fourth lens 4. On the one hand, the ratio of its center thickness T4 to the total optical length TTL of the optical-mechanical lens module satisfies 10%≤T4 / TTL≤13%; on the other hand, the refractive index of the fourth lens 4 is in the range of 1.8~1.9.

[0142] The center thickness T4 of the fourth lens 4 accounts for 10% to 13% of the total optical length TTL. This ratio ensures that the fourth lens 4 has an appropriate optical power distribution within the optical-mechanical lens module. When light exits from the X-cube color-combining prism 6 and enters the fourth lens 4, the suitable center thickness T4 ensures accurate focusing of the light as it passes through the fourth lens 4. If T4 / TTL is too small, the fourth lens 4 may not provide sufficient optical power, resulting in insufficient focusing and affecting image sharpness; if T4 / TTL is too large, it may introduce excessive aberrations, such as spherical aberration and chromatic aberration. By controlling it within the range of 10% to 13%, the fourth lens 4 can effectively cooperate with other lenses to correct aberrations while focusing light, thereby improving image quality.

[0143] The refractive index of the fourth lens 4 is between 1.8 and 1.9, which helps to further optimize the aberration correction effect. Materials with different refractive indices have different abilities to refract light. Within this refractive index range, the fourth lens 4 can better cooperate with other lenses to correct chromatic aberration and monochromatic aberration in the optical-mechanical lens module. For example, in correcting chromatic aberration, a suitable refractive index allows light of different wavelengths to have closer refraction angles when passing through the fourth lens 4, reducing dispersion and thus improving the color reproduction and sharpness of the image.

[0144] After receiving the light emitted from the X-cube color-combining prism 6, the fourth lens 4 passes sequentially through the third lens 3, the second lens 2, and the first lens 1 before reaching the aperture 8. A suitable T4 / TTL ratio and refractive index range ensure that the angle and position of the light emitted from the fourth lens match the requirements of subsequent lenses. If the parameters of the fourth lens 4 are unsuitable, it may lead to excessive angular deviation of the emitted light, preventing subsequent lenses from effectively receiving and adjusting the light, thus affecting the light transmission efficiency of the entire optical-mechanical lens module. By controlling these two parameters in this example, smooth light transmission between lenses can be ensured, improving the stability and reliability of the module.

[0145] The appropriate thickness ratio and refractive index range of the fourth lens 4 help enhance the optical-mechanical lens module's resistance to environmental changes. For example, lenses made of different materials may expand and contract with temperature changes. Appropriate parameters can reduce lens deformation and optical performance degradation caused by thermal stress, ensuring that the system maintains stable imaging quality under different environments.

[0146] In some examples of this application, the ratio of the center thickness T3 of the third lens 3 to the total optical length TTL of the optical-mechanical lens module is: 3%≤T3 / TTL≤6%.

[0147] In the design of the optical-mechanical lens module in this application, it is specified that the ratio of the center thickness T3 of the third lens 3 to the total optical length TTL of the optical-mechanical lens module satisfies 3%≤T3 / TTL≤6%. The third lens 3 is located in a specific position in the optical-mechanical lens module. It receives the light after it has been adjusted by the fourth lens 4 (positive power aspherical lens). The light is then transmitted to the aperture stop 8 through the second lens 2 and the first lens 1. The proportion of its center thickness T3 has an important impact on the performance of the optical-mechanical lens module.

[0148] When 3% ≤ T3 / TTL ≤ 6%, the third lens 3 has a suitable center thickness T3. This allows it to accurately focus and adjust the light from the fourth lens 4 within the optical-mechanical lens module. If T3 / TTL is too small, meaning the center thickness of the third lens 3 is too thin, its optical power may be insufficient, failing to focus the light to the ideal position. This can lead to scattering or inaccurate focusing during subsequent transmission, affecting image clarity. If T3 / TTL is too large, the third lens 3 is too thick, potentially introducing excessive aberrations that interfere with normal focusing, also reducing image quality. For example, during imaging, a suitable center thickness T3 of the third lens 3 ensures that the light enters the second lens 2 at a more precise angle and position after passing through it, laying a good foundation for subsequent imaging steps.

[0149] The third lens 3 works in conjunction with the fourth lens 4. The fourth lens 4 adjusts the combined light emitted from the X-cube color combining prism 6. The third lens 3 adjusts the direction of the light according to the overall requirements of the optical-mechanical lens module, so that the light can be transmitted to other optical elements more smoothly, reducing energy loss and directional deviation of the light during propagation and improving the light utilization rate.

[0150] The proportion of the center thickness T3 of the third lens 3 plays a crucial role in correcting aberrations in the optical engine lens module. Within this proportion range, the third lens 3 can work together with other lenses to effectively correct aberrations.

[0151] By controlling T3 / TTL within the range of 3% to 6%, the third lens 3 helps improve the uniformity of image quality across the image plane. In the optomechanical lens module of this application, the image quality of different areas of the image plane may vary due to the effects of light propagation and aberrations. A suitable center thickness T3 of the third lens 3 can adjust the focusing of light at various positions on the image plane, reducing the difference in image quality between the edge and center areas, resulting in consistent sharpness and color reproduction across the entire projected image, and providing users with a superior visual experience.

[0152] Furthermore, a T3 / TTL ratio of 3% to 6% helps achieve a compact optical structure design for the optical engine lens module. In AR optical display devices, a compact optical engine lens module can reduce the size and weight of the device. The third lens 3, while meeting optical performance requirements, achieves its space-saving design through a suitable thickness ratio, enabling the optical engine lens module to achieve efficient optical functions within a limited space, thus meeting the miniaturization and lightweight requirements of AR optical display devices.

[0153] The optimal center thickness ratio of the third lens 3 and the fourth lens 4 works together to optimize the propagation path of light within the entire optical-mechanical lens module. The center thickness T4 of the fourth lens 4 refracts and focuses the light, laying the foundation for subsequent light propagation. The third lens 3, based on the overall requirements of the optical-mechanical lens module, makes finer adjustments to the light, allowing it to pass through other optical elements at a more suitable angle and direction. This synergistic effect reduces light scattering and loss during propagation, improves light utilization, and thus enhances image brightness.

[0154] The constraint on the center thickness ratio of the third lens 3 and the fourth lens 4 helps to achieve a compact optical structure design for the optical engine lens module. In AR optical display devices, a compact optical engine lens module can reduce the size and weight of the device and improve portability. The fourth lens 4 and the third lens 3, while meeting their respective optical performance requirements, do not occupy excessive space due to their appropriate center thickness ratio. Their rational arrangement with other lenses enables the entire optical engine lens module to achieve efficient optical functions within a limited space, meeting the miniaturization and lightweight requirements of AR optical display devices.

[0155] In some examples of this application, the ratio of the total optical length TTL of the optical engine lens module to the maximum aperture D1 of the lens in the optical engine lens module satisfies: 11.3 < (TTL / D1) < 2.

[0156] See also in this application. Figure 1 The fifth lens 5 is the lens with the largest aperture in the entire optical-mechanical lens module, that is, the aperture of the fifth lens 5 is D1.

[0157] When the TTL / D1 ratio is between 1.3 and 2, the total optical length (TTL) of the optical-mechanical lens module can be effectively controlled. A smaller ratio means that, given a maximum lens aperture (D1), the total optical length will not be excessive. For example, if D1 is fixed, a ratio close to 1.3 results in a relatively short TTL, which helps to achieve a compact design of the lens module. In AR optical display devices, a compact optical-mechanical lens module can reduce the size and weight of the device, meeting users' needs for lightweight and compact products.

[0158] The ratio range in this example controls the overall optical length while also considering optical performance. If the ratio is too small in pursuit of extreme compactness, the lens design may be overly constrained, failing to meet the optical system's requirements for light focusing and aberration correction. A ratio range of 1.3 to 2 allows for reasonable control of the overall optical length while ensuring optical performance, achieving a balance between performance and size. For example, in some high-end AR optical display devices, both high-quality imaging performance and a compact size are required; this ratio range effectively meets this need.

[0159] To achieve a wide field of view of 72.8°, the TTL / D1 ratio plays a crucial role in the optical-mechanical lens module of this application. A larger field of view requires the optical-mechanical lens module to receive and process light from a wider range of angles. When the ratio is between 1.3 and 2, the optical-mechanical lens module has sufficient space and structure to design suitable lens combinations to achieve wide field of view coverage. For example, the fifth lens 5, as a lens with a specific aperture D1, when combined with other lenses at a reasonable TTL, allows light to enter the lens over a wide angle range and achieve accurate imaging. If the TTL is too long or too short, it may affect the propagation and focusing of light within the wide field of view, leading to increased aberrations and blurred images at the edges of the field of view.

[0160] In some examples of this application, the optical-mechanical lens module further includes an aperture stop 8 located on the object side of the first lens 1 and a display unit 7 located on the image side of the fifth lens 5;

[0161] The effective focal lengths of each lens in the optical-mechanical lens module are as follows:

[0162] The focal length of the first lens 1 is f1, where 10.5mm ≤ f1 ≤ 12.5mm;

[0163] The focal length of the second lens 2 is f2, 9.06mm≤f2≤11.06mm;

[0164] The focal length of the third lens 3 is f3, -5.56mm≤f3≤-3.56mm;

[0165] The focal length of the fourth lens 4 is f4, where 2.59mm ≤ f4 ≤ 4.59mm;

[0166] The focal length of the fifth lens 5 is f5, -8.47mm≤f5≤-6.47mm;

[0167] The first lens 1, the second lens 2, the third lens 3 and the fifth lens 5 are plastic lenses, and the fourth lens 4 is a glass lens.

[0168] The aperture 8 is designed as a front aperture, which is located on the object side of the first lens 1, that is, in the optical path between the first lens 1 and the coupling region of the external diffractive waveguide device (not shown in the figure).

[0169] As a key optical control component, the front aperture primarily controls the light flux entering subsequent optical elements (such as the diffractive waveguide device mentioned above). By limiting the aperture size of the beam, aperture 8 helps to effectively reduce interference from stray light and non-imaging light, ensuring that only light within a specific aperture range can pass smoothly and enter subsequent optical elements (such as the diffractive waveguide device) for processing. This design significantly improves image sharpness and contrast, avoiding the impact of stray light on image quality.

[0170] From the perspective of the display unit 7, it can be composed of chips capable of emitting different colors of light. For example, the R display chip is responsible for emitting red light, the G display chip is responsible for emitting green light, and the B display chip is responsible for emitting blue light. These three colors are the basis for image color, and through combinations of different intensities and proportions, a rich variety of colors can be presented. The red, green, and blue light processed by the fifth lens 5 can be combined in the X-cube color combining prism 6, providing mixed light containing complete color information for subsequent projection imaging.

[0171] In the optical-mechanical lens module provided in this application, the first lens 1 and the second lens 2 are positive power lenses, and their focal length range enables them to converge the light entering the optical-mechanical lens module. The relatively large focal lengths of these two lenses, combined with the focal length range design of the third lens 3, the fourth lens 4, and the fifth lens 5, ensure that light within the entire large field of view (FOV) range (72.8°) can form a clear image on the image plane, achieving high-quality imaging under a large field of view.

[0172] The combination of lenses of different materials and focal lengths can work together to correct various aberrations in the optical-mechanical lens module. Four plastic lenses (first lens 1, second lens 2, third lens 3 and fifth lens 5) and one glass lens (fourth lens 4) have different optical properties. They work together to correct various aberrations, making the image on the image plane clearer and more accurate, and improving the image quality.

[0173] In a large field of view, the image quality of different areas of the image plane may vary due to light propagation and aberrations. By appropriately setting the focal length of each lens, light can be evenly distributed across the entire image plane, reducing the difference in image quality between the edges and the center. For example, the fourth lens 4 and the fifth lens 5, based on their focal length range, precisely focus and adjust the light in the edge field of view, avoiding edge blurring or distortion, thus ensuring consistent sharpness and color reproduction across the entire projected image.

[0174] This application employs a combination of plastic and glass lenses, taking into account both cost factors and optimized system performance. Plastic lenses offer advantages such as low cost and ease of processing, making them suitable for manufacturing the first lens 1, second lens 2, third lens 3, and fifth lens 5. They can be fabricated aspherical lenses according to optical design requirements to achieve better aberration correction. Glass lenses, on the other hand, possess excellent optical properties such as high refractive index and dispersion coefficient. The fourth lens 4, made of glass, further enhances the imaging quality and stability of the optical-mechanical lens module.

[0175] The focal length range of each lens is set to achieve optical performance while also considering the compactness of the optical structure and manufacturing cost of the optical-mechanical lens module. A reasonable focal length range allows the spacing between lenses and the overall optical length to be controlled within a suitable range, which is beneficial for achieving a compact design of the optical-mechanical lens module. At the same time, a suitable focal length range also reduces the difficulty and cost of lens manufacturing. For example, the focal length range of each lens avoids excessively large focal lengths that would result in an overly large system size, and also avoids excessively small focal lengths that would increase the complexity of the manufacturing process.

[0176] In a preferred embodiment, please refer to the optical structure of the optical-mechanical lens module. Figure 1 As shown, the effective focal lengths of the first lens 1 to the fifth lens 5 in this optical engine lens module are as follows:

[0177] The focal length f1 of the first lens 1 is 11.5 mm;

[0178] The focal length f2 of the second lens 2 is 11.06 mm;

[0179] The focal length f3 of the third lens 3 is -4.56mm;

[0180] The focal length f4 of the fourth lens 4 is 3.59mm;

[0181] The focal length f5 of the fifth lens 5 is -7.47mm;

[0182] The first lens 1, the second lens 2, the third lens 3 and the fifth lens 5 are plastic lenses, and the fourth lens 4 is a glass lens;

[0183] Based on this, the optical parameters of the optical engine lens module are shown in Tables 1 and 2:

[0184] Table 1

[0185]

[0186] Table 2

[0187]

[0188] In the above example, the main parameters of the optical-mechanical lens module design include: total focal length F = 4.425mm; FOV = 72.8°; entrance pupil diameter = 1.9mm; entrance pupil distance = 0.2mm; pixel size = 5μm; image plane size = 5mm~6mm; optical distortion <15%, see [reference] Figure 4 The operating wavelength is 460nm~618nm. High image quality output with an MTF value > 0.55@100lp / mm is achieved within the 460nm-618nm band. See [link / reference]. Figure 5 .

[0189] In some examples of this application, the optical-mechanical lens module has a field of view (FOV) of 72.8°±0.5° when the operating wavelength is 460nm~618nm.

[0190] In the optical-mechanical lens module provided in this application, when the optical-mechanical lens module is in the working wavelength band of 460nm~618nm, its full field of view (FOV) can reach 72.8°, allowing for a slight deviation of ±0.5°. This means that the optical-mechanical lens module can achieve a relatively large field of view range of 72.3°~73.3° when processing light in this wavelength band.

[0191] The optical-mechanical lens module of this application will be further described below through Examples 1 to 4.

[0192] Example 1

[0193] See Figure 6 The optical-mechanical lens module provided in this embodiment 1 includes the following optical elements sequentially from the object side to the image side along the optical axis:

[0194] Aperture 8 is the front aperture;

[0195] The first lens 1 is a plastic aspherical positive lens;

[0196] The second lens 2 is a plastic aspherical positive lens;

[0197] The third lens, 3, is a plastic aspherical negative lens;

[0198] The fourth lens, 4, is a glass aspherical positive lens;

[0199] X-cube color-combining prism 6 is made of glass;

[0200] The fifth lens, 5, is a plastic aspherical negative lens; and,

[0201] Display unit 7 is capable of emitting R, G, and B light.

[0202] The optical parameters of the optical-mechanical lens module shown in this embodiment 1 are shown in Tables 3 and 4 below. Table 4 shows the aspherical design of each aspherical lens in Table 3.

[0203] Table 3

[0204]

[0205] Table 4

[0206]

[0207] For the optical-mechanical lens module provided in Embodiment 1, see [link to documentation]. Figure 7 , Figure 7 This is a modulation transfer function diagram of the optical-mechanical lens module provided in Embodiment 1, from... Figure 7 It can be seen that MTF > 0.48 @ 100 lp / mm.

[0208] Example 2

[0209] See Figure 8 The optical-mechanical lens module provided in this embodiment 2 includes the following optical elements sequentially from the object side to the image side along the optical axis:

[0210] Aperture 8 is the front aperture;

[0211] The first lens 1 is a plastic aspherical positive lens;

[0212] The second lens 2 is a plastic aspherical positive lens;

[0213] The third lens, 3, is a plastic aspherical negative lens;

[0214] The fourth lens, 4, is a glass aspherical positive lens;

[0215] X-cube color-combining prism 6 is made of glass;

[0216] The fifth lens, 5, is a plastic aspherical negative lens; and,

[0217] Display unit 7 is capable of emitting R, G, and B light.

[0218] The specific optical parameters of the optomechanical lens module shown in this embodiment 2 are shown in Tables 5 and 6 below. Table 6 shows the aspherical design of each aspherical lens in Table 5.

[0219] Table 5

[0220]

[0221] Table 6

[0222]

[0223] For the optical-mechanical lens module provided in Embodiment 2, see [link to documentation]. Figure 9 , Figure 9 The modulation transfer function diagram of the optical-mechanical lens module provided in Embodiment 2 is shown below. Figure 9 It can be seen that MTF > 0.48 @ 100 lp / mm.

[0224] Example 3

[0225] See Figure 10 The optical-mechanical lens module provided in this embodiment 3 includes the following optical elements sequentially from the object side to the image side along the optical axis:

[0226] Aperture 8 is the front aperture;

[0227] The first lens 1 is a plastic aspherical positive lens;

[0228] The second lens 2 is a plastic aspherical positive lens;

[0229] The third lens, 3, is a plastic aspherical negative lens;

[0230] The fourth lens, 4, is a glass aspherical positive lens;

[0231] X-cube color-combining prism 6 is made of glass;

[0232] The fifth lens, 5, is a plastic aspherical negative lens; and,

[0233] Display unit 7 is capable of emitting R, G, and B light.

[0234] The specific optical parameters of the optical-mechanical lens module shown in this embodiment 3 are shown in Tables 7 and 8 below. Table 8 shows the aspherical design of each aspherical lens in Table 7.

[0235] Table 7

[0236]

[0237] Table 8

[0238]

[0239] For the optical-mechanical lens module provided in Embodiment 3, see [link to documentation]. Figure 11 , Figure 11 The modulation transfer function diagram of the optical-mechanical lens module provided in Embodiment 3 is shown below. Figure 11 It can be seen that MTF > 0.48 @ 100 lp / mm.

[0240] Example 4

[0241] See Figure 12 The optical-mechanical lens module provided in this embodiment 4 includes the following optical elements sequentially from the object side to the image side along the optical axis:

[0242] Aperture 8 is the front aperture;

[0243] The first lens 1 is a plastic aspherical positive lens;

[0244] The second lens 2 is a plastic aspherical positive lens;

[0245] The third lens, 3, is a plastic aspherical negative lens;

[0246] The fourth lens, 4, is a glass aspherical positive lens;

[0247] X-cube color-combining prism 6 is made of glass;

[0248] The fifth lens, 5, is a plastic aspherical negative lens; and,

[0249] Display unit 7 is capable of emitting R, G, and B light.

[0250] The specific optical parameters of the optical-mechanical lens module shown in this embodiment 4 are shown in Tables 9 and 10 below. Table 10 shows the aspherical design of each aspherical lens in Table 9.

[0251] Table 9

[0252]

[0253] Table 10

[0254]

[0255] For the optical-mechanical lens module provided in Embodiment 4, see [link to documentation]. Figure 13 , Figure 13 The modulation transfer function diagram of the optical-mechanical lens module provided in Embodiment 4 is shown below. Figure 13 It can be seen that MTF > 0.48 @ 100 lp / mm.

[0256] The optical distortion of the optical engine lens modules provided in Embodiments 1 to 4 above is less than 15%.

[0257] According to another embodiment of this application, an AR optical display device is provided, the AR optical display device comprising: an optical engine lens module and an optical waveguide device as described above; wherein the diameter of the aperture 8 of the optical engine lens module matches the entrance pupil diameter of the optical waveguide device.

[0258] The specific implementation of the AR optical display device in this application can refer to the various embodiments of the optical engine lens module described above. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0259] 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.

[0260] 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. An optical-mechanical lens module, characterized in that, Along the optical axis from the object side to the image side, the following are included in sequence: The first lens (1) is an aspherical positive lens; The second lens (2) is an aspherical positive lens; The third lens (3) is an aspherical negative lens; The fourth lens (4) is an aspherical positive lens; X-cube color-combining prism (6); and, The fifth lens (5) is an aspherical negative lens; The total focal length F of the optical engine lens module is 4.1mm < F < 4.8mm; The focal length f1 of the first lens (1) and the total focal length F satisfy: 2.3≤f1 / F≤2.9; The focal length f2 of the second lens (2) satisfies the total focal length F as follows: 2.1≤f2 / F≤2.

4.

2. The optical-mechanical lens module according to claim 1, characterized in that, The fifth lens (5) is a field lens, and its object side is an aspherical surface with a central concave shape; And it meets the following air gap constraints: The distance A1 between the center point of the object side surface of the fifth lens (5) and the light-emitting surface of the X-cube color-combining prism (6) is 0.3mm≤A1≤0.35mm; The distance A2 between the object side surface of the fifth lens (5) at 0.45mm and the light-emitting surface of the X-cube color-combining prism (6) is 0.28mm≤A2≤0.32mm; The distance A3 between the maximum aperture of the object side of the fifth lens (5) and the light-emitting surface of the X-cube color-combining prism (6) is 0.5mm≤A3≤0.6mm.

3. The optical-mechanical lens module according to claim 1, characterized in that, The first lens (1) has an object side surface with a sagitta of S1 at the maximum aperture and an object side surface with a sagitta of S2 at the maximum aperture, and satisfies the sagitta ratio relationship: 2 < S2 / S1 < 2.

3.

4. The optical-mechanical lens module according to claim 1 or 3, characterized in that, The first lens (1) has an image-side tangent at the maximum aperture with an angle of A1 to the optical axis, and an object-side tangent at the maximum aperture with an angle of A2 to the optical axis, satisfying the following angular relationships: 1°<A1-A2<12°, and 0.9<A2 / A1<1.

1.

5. The optical-mechanical lens module according to claim 1, characterized in that, The object side of the second lens (2) has a sagitta of S3 at the maximum aperture, and the image side has a sagitta of S4 at the maximum aperture, and the sagitta ratio is satisfied: 2.3 < S4 / S3 < 2.

7.

6. The optical-mechanical lens module according to claim 1 or 5, characterized in that, The second lens (2) has an image-side tangent at the maximum aperture with an angle of A3 with the optical axis, and an object-side tangent at the maximum aperture with an angle of A4 with the optical axis, satisfying the angle relationship: 20° < A3 - A4 < 60°.

7. The optical-mechanical lens module according to claim 1, characterized in that, The first lens (1), the second lens (2), the third lens (3), the fourth lens (4), and the fifth lens (5) satisfy: 2.6 < (T1 + T2 + T4) / (T3 + T5) < 3.2; where T1, T2, T3, T4, and T5 are the center thicknesses of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), and the fifth lens (5), respectively.

8. The optical-mechanical lens module according to claim 1 or 7, characterized in that, The ratio of the center thickness T4 of the fourth lens (4) to the total optical length TTL of the optical-mechanical lens module is: 10%≤T4 / TTL≤13%; The refractive index of the fourth lens (4) is 1.8~1.

9.

9. The optical-mechanical lens module according to claim 1 or 7, characterized in that, The ratio of the center thickness T3 of the third lens (3) to the total optical length TTL of the optical-mechanical lens module is: 3%≤T3 / TTL≤6%.

10. The optical-mechanical lens module according to claim 1, characterized in that, The ratio of the total optical length TTL of the optical engine lens module to the maximum aperture D1 of the lens in the optical engine lens module satisfies: 11.3 < (TTL / D1) < 2.

11. The optical-mechanical lens module according to claim 1, characterized in that, The optical-mechanical lens module also includes an aperture stop (8) located on the object side of the first lens (1) and a display unit (7) located on the image side of the fifth lens (5). The effective focal lengths of each lens in the optical-mechanical lens module are as follows: The focal length of the first lens (1) is f1, 10.5mm≤f1≤12.5mm; The focal length of the second lens (2) is f2, 9.06mm≤f2≤11.06mm; The focal length of the third lens (3) is f3, -5.56mm≤f3≤-3.56mm; The focal length of the fourth lens (4) is f4, 2.59mm≤f4≤4.59mm; The focal length of the fifth lens (5) is f5, -8.47mm≤f5≤-6.47mm; The first lens (1), the second lens (2), the third lens (3) and the fifth lens (5) are plastic lenses, and the fourth lens (4) is a glass lens.

12. The optical-mechanical lens module according to claim 1, characterized in that, The optical-mechanical lens module has a field of view (FOV) of 72.8°±0.5° when operating in the wavelength range of 460nm~618nm.

13. An AR optical display device, characterized in that, include: The optical-mechanical lens module as described in any one of claims 1-12; and An optical waveguide device, wherein the diameter of the aperture of the optical-mechanical lens module is matched with the entrance pupil diameter of the optical waveguide device.

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