Optical-mechanical lens module and AR optical display device

Abstract

This application provides an optical-mechanical lens module and an AR optical display device. The optical-mechanical lens module includes, along the optical axis from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The first lens, the third lens, and the fourth lens all have positive optical power, while the second lens and the fifth lens both have negative optical power. The refractive index Nd3 of the third lens is 1.48 ≤ Nd3 ≤ 1.59, and the refractive index Nd5 of the fifth lens is 1.9 ≤ Nd5 ≤ 1.95. All lenses from the first lens to the fifth lens are aspherical glass lenses. The total optical length TTL of the optical-mechanical lens module is < 12 mm. The sagitta of the object side of the fifth lens at its maximum aperture is S5, and satisfies: 0.1 < S5 / TTL < 0.35.

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 continuous advancement of optical technology, augmented reality (AR) technology has been widely applied in the field of smart wearable devices. As a core component of AR devices, the optical engine lens module (i.e., the light engine part) has undergone significant technological iterations, from the early digital light processing (DLP) optical engine to the liquid crystal on silicon (LCOS) optical engine, and then to the single green micro light-emitting diode (u-LED) optical engine, continuously driving the development of AR display technology.

[0003] Currently, full-color u-LED optical engines are widely recognized as the core direction for the development of next-generation AR technology. However, their optical system design faces challenges: how to achieve a breakthrough in large field of view (FOV) while maintaining a compact size. Currently, full-color u-LED optical engines generally employ a technology that combines three RGB monochrome panels using an X-cube prism. However, this design is limited by existing optical architecture, resulting in a relatively large overall optical length and a technical bottleneck that makes it difficult to break through the 65° maximum field of view barrier.

[0004] The trade-off between the size of the optical engine and the field of view not only limits the wearing comfort of AR optical display devices but also restricts the further enhancement of user immersion, becoming a key factor hindering the expansion of AR technology into wider application scenarios. Therefore, how to achieve a balance between small size and a large field of view by optimizing the design of the optical engine lens module while ensuring optical performance has become a core issue that urgently needs to be addressed in the current 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 effectively solves the contradiction between module size and field of view in the prior art.

[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: The first lens has positive optical power; The second lens has negative optical power; The third lens has positive optical power and a refractive index Nd3 of 1.48≤Nd3≤1.59; The fourth lens has positive optical power; and, The fifth lens has negative optical power and its refractive index Nd5 is 1.9≤Nd5≤1.95; The first lens through the fifth lens are all aspherical glass lenses; The total optical length (TTL) of the optical engine lens module is less than 12 mm. The object-side surface of the fifth lens has a sagitta of S5 at its maximum aperture, and satisfies the relationship: 0.1 < S5 / TTL < 0.35.

[0007] Optionally, the focal length f5 of the fifth lens satisfies: -200mm < f5 < -180mm; and the focal length f5 of the fifth lens and the total focal length F of the optical-mechanical lens module satisfy: 18 < |f5 / F| < 26.

[0008] Optionally, the total focal length F of the optical engine lens module satisfies: 8.5mm < F < 9.0mm.

[0009] Optionally, the center thickness of each lens in the optical-mechanical lens module satisfies: 2.2 < (T1 + T3 + T4) / (T2 + T5) < 2.6, where T1, T2, T3, T4, and T5 are the center thicknesses of the first lens to the fifth lens, respectively.

[0010] Optionally, the center thickness T3 of the third lens and the total optical length TTL of the optomechanical lens module satisfy the following condition: 15%≤T4 / TTL≤18%.

[0011] Optionally, the angle between the tangent on the image side of the third lens at its maximum aperture and the optical axis is A1, and the angle between the tangent on the object side at its maximum aperture and the optical axis is A2, satisfying the angular relationships: 30°<|A1-A2|<60°, and 1.7<|A2 / A1|<2.3.

[0012] Optionally, the center thickness T4 of the fourth lens and the total optical length TTL of the optical-mechanical lens module satisfy the following condition: 7% ≤ T4 / TTL ≤ 10%.

[0013] Optionally, the fourth lens has an object-side elevation of S3 at the maximum aperture and an image-side elevation of S4 at the maximum aperture, satisfying: 3.5 < S3 / S4 < 4.2.

[0014] Optionally, the angle between the tangent on the image side of the fourth lens at its maximum aperture and the optical axis is A3, and the angle between the tangent on its object side at its maximum aperture and the optical axis is A4, satisfying the following angular relationships: 10° < |A3-A4| < 30°, and 0.7 < |A3 / A4| < 1.5.

[0015] Optionally, the sagitta of the object side of the second lens at the maximum aperture is S1, and the sagitta of the image side at the maximum aperture is S2, and satisfies: 2.4 < S2 / S1 < 2.7.

[0016] Optionally, the total optical length (TTL) of the optical engine lens module is equal to the maximum aperture (D) of all lenses. max The ratio satisfies: 1.05 < TTL / D max <1.4.

[0017] Optionally, the optical engine lens module further includes: An aperture stop is located on the object side of the first lens; and The display unit, located on the image side of the fifth lens, is used to emit projected light rays.

[0018] Secondly, embodiments of this application provide an AR optical display device, the AR optical display device comprising: As described in the first aspect, the optical engine lens module; 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.

[0019] The beneficial effects of this application are as follows: The optical-mechanical lens module provided in this application achieves a technological breakthrough by arranging five aspherical glass lenses with specific optical power distribution and refractive index range along the optical axis from the object side to the image side, resulting in an optical total length (TTL) of less than 12mm and a field of view (FOV) of 70° or more. The optical design provided in this application, while maintaining a compact structure (e.g., TTL less than 12mm), effectively overcomes the bottleneck of the FOV (Field of View) in existing full-color u-LED optical engine technology, which is difficult to exceed 65°, thus enhancing the user immersion of AR optical display devices. By optimizing lens combination and material selection, the optical length of the optical engine is significantly reduced compared to the traditional X-cube color combination scheme, effectively resolving the contradiction between the size of the optical engine and the field of view, and improving wearing comfort. In particular, the fifth lens uses a high refractive index material (1.9≤Nd5≤1.95) and controls the ratio of its object-side sag to its total length (0.1<S5 / TTL<0.35), so that optical distortion can be controlled to a level of less than 15%, which significantly improves the image quality compared to the optical distortion of more than 20% in the traditional scheme, and solves the problem of edge image quality degradation at large field of view.

[0020] This application solves technical problems such as limited field of view, large size of optical-mechanical lens module and poor imaging quality through innovative optical architecture design, providing key technical support for the miniaturization and high performance development of AR optical display devices.

[0021] 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

[0022] 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.

[0023] Figure 1 This application provides an optical structure and optical path diagram of an optical-mechanical lens module; Figure 2 A partial structural schematic diagram of the third lens in the optical-mechanical lens module provided in this application; Figure 3 This is a partial structural diagram of the fourth lens in the optical-mechanical lens module provided in this application; Figure 4 for Figure 1 The optical distortion diagram of the optical-mechanical lens module shown in the figure is as follows; Figure 5 for Figure 1 The modulation transfer function diagram of the optomechanical lens module is shown in the figure; Figure 6 This is a schematic diagram of the optical structure and optical path of the optical-mechanical lens module provided in Embodiment 1 of this application; Figure 7 for Figure 6 The modulation transfer function diagram of the optomechanical lens module is shown in the figure; Figure 8 This is a schematic diagram of the optical structure and optical path of the optical-mechanical lens module provided in Embodiment 2 of this application; Figure 9 for Figure 8 The modulation transfer function diagram of the optomechanical lens module is shown in the figure; Figure 10 This is a schematic diagram of the optical structure and optical path of the optical-mechanical lens module provided in Embodiment 3 of this application; Figure 11 for Figure 10 The modulation transfer function diagram of the optomechanical lens module is shown in the figure.

[0024] Explanation of reference numerals in the attached figures: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Aperture; 7. Display unit. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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, and a fifth lens 5. The first lens 1, the third lens 3, and the fourth lens 4 all have positive optical power, while the second lens 2 and the fifth lens 5 both have negative optical power. The refractive index Nd3 of the third lens 3 is 1.48 ≤ Nd3 ≤ 1.59, and the refractive index Nd5 of the fifth lens 5 is 1.9 ≤ Nd5 ≤ 1.95. All lenses from the first lens 1 to the fifth lens 5 are aspherical glass lenses. The total optical length (TTL) of the optical engine lens module is < 12 mm. The sag of the object side surface of the fifth lens 5 at its maximum aperture is S5, and satisfies: 0.1 < S5 / TTL < 0.35.

[0032] 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).

[0033] The optical-mechanical lens module provided in this application embodiment has a light propagation path design as follows: Figure 1 As shown: Light is projected from the image-side display unit 7, passes sequentially through the fifth lens 5, the fourth lens 4, the third lens 3, the second lens 2, and the first lens 1, and finally exits from the object-side aperture 6. The projected light rays can be transmitted to the human eye through external diffractive optical devices (such as diffractive waveguides) to achieve imaging.

[0034] It should be noted that the core optimization scope of this application mainly covers the optical design inside the optical engine lens module, and does not involve external diffractive optical devices. Therefore, diffractive optical devices are not specifically described in this application.

[0035] The optical-mechanical lens module provided in this application embodiment includes a fifth lens 5 disposed near the image side. See also... Figure 1 The fifth lens 5 is designed to have negative optical power (i.e., optical power < 0), and its refractive index Nd5 is specifically 1.9 ≤ Nd5 ≤ 1.95, that is, the fifth lens 5 is made of high refractive index glass material.

[0036] The sagitta S5 of the object-side surface (i.e., the surface near the object side) of the fifth lens 5 at its maximum aperture satisfies the relationship: 0.1 < S5 / TTL < 0.35. This parameter indicates that the object-side surface of the fifth lens 5 has a relatively large degree of concavity, and its radius of curvature is designed to ensure that the ratio of the vertical concavity (sagitta) of its object-side edge relative to the optical axis to the total optical length (TTL) of the optical-mechanical lens module is controlled between 20% and 27%. Figure 1 The image-side sagitta of the fifth lens 5 is basically the same as that of the object-side sagitta, meaning that the difference between the center thickness and the edge thickness of the fifth lens 5 is minimal, resulting in a thin concave lens structure with near-zero optical power (almost no optical power). This surface design achieves precise control of the light propagation path while maintaining the lens's thinness.

[0037] As the lens closest to the image side (the side where the display unit 7 is located), the fifth lens 5 is designed with a high refractive index glass material (Nd5=1.9~1.95), and combined with its unique concave surface design, it can perform at least the following optical functions: Field curvature and astigmatism correction: Through the symmetrical concave structure of the object side and the image side, the fifth lens 5 can effectively compensate for the field curvature and astigmatism introduced by the module due to the large field of view (such as FOV≥70°), so that the light rays from different field of view converge on the object side (one side of the aperture 6), and improve the uniformity of edge image quality. Distortion control: Its negative optical power characteristics and high refractive index materials work together to control the optical distortion of the optical engine lens module to a level of <15%, which meets the high precision requirements of AR optical display devices for geometric distortion. Aberration balance optimization: The negative optical power of the fifth lens 5 can complement the positive optical power of the fourth lens 4, achieving systematic cancellation of aberrations. Simultaneously, the aspherical surface design facilitates further correction of higher-order aberrations, ensuring that the peak value of the MTF curve is >0.6 across the entire field of view. (See [link to relevant documentation]). Figure 5 .

[0038] In the optical engine lens module provided in this application embodiment, the fourth lens 4 is located on the side of the fifth lens 5 away from the image side (display unit 7 side). It adopts a glass aspherical design and is configured as a positive power lens. The fourth lens 4 processes the light beam emitted from the fifth lens 5 through its positive power characteristics, making the light propagate more concentrated towards the object side (i.e., the side where the aperture 6 is), thereby optimizing the overall optical path layout of the module. Its glass aspherical design, through the continuous change of surface curvature, can specifically correct the aberrations introduced by the module due to a large field of view (e.g., FOV≥70°), and can also improve the light convergence accuracy of the edge field of view, thereby improving the imaging uniformity across the entire field of view and ensuring that the projected image remains clear and sharp from the center to the edge.

[0039] In the optical-mechanical lens module provided in this application embodiment, the third lens 3 is designed with positive optical power. It adopts a glass aspherical design, and its optical material has a refractive index Nd3 of 1.48~1.59. This third lens 3 achieves beam convergence through its moderate refractive index characteristics. At the same time, the curvature of the aspherical surface of the glass material is optimized, which can effectively correct chromatic aberration and aberration under a large field of view (such as FOV≥70°), ensuring the clarity and color reproduction consistency of the image across the entire field of view.

[0040] In the optomechanical lens module provided in this application embodiment, the second lens 2 adopts a glass aspherical design and is configured as a negative optical power lens. Through its negative optical power characteristics, it appropriately diverges the beam converged by the preceding lens, achieving a smooth transition of the optical path. The aspherical surface, through continuous curvature variation, can specifically correct spherical aberration and field curvature caused by a large field of view (e.g., FOV ≥ 70°), avoiding edge image quality degradation due to excessive light divergence. Simultaneously, it provides a suitable beam state for the subsequent positive optical power convergence of the first lens 1, ensuring the stability of light propagation and imaging uniformity across the entire field of view.

[0041] In the optical-mechanical lens module provided in this application embodiment, the first lens 1 is located on the object side of the optical-mechanical lens module (i.e., on the side where the aperture 6 is located). As an optical element for light projection, it functions to converge and guide the projected light rays to the aperture 6. The first lens 1 adopts a positive optical power glass aspherical design. Its aspherical surface, through curvature adjustment, can effectively eliminate spherical aberration and coma, ensuring that the light rays pass through the aperture 6 at an ideal angle and enter the external diffraction optical device. This provides a beam foundation with high uniformity and low distortion for subsequent optical paths, ultimately ensuring the clarity and color reproduction quality of the projected image.

[0042] The optical-mechanical lens module provided in this application embodiment is described in [reference]. Figure 1 The optical power is arranged in a "positive-negative-positive-positive-negative" sequence from the object side to the image side, achieving a balance between aberration correction and beam control. Specifically: The first lens 1 (positive optical power) and the second lens 2 (negative optical power) form an aberration correction; The third lens 3 (positive power) and the fourth lens 4 (positive power) enhance the beam converging ability; The fifth lens 5 (negative optical power) ultimately optimizes image quality and controls distortion.

[0043] The above arrangement can also effectively compress the total optical length of the optical engine lens module (e.g., TTL < 12mm), while achieving an ultra-large field of view of FOV ≥ 70°.

[0044] In the optical-mechanical lens module provided in this application embodiment, the third lens 3 is made of a medium refractive index material (1.48≤Nd3≤1.59), which ensures beam converging efficiency while controlling costs; the fifth lens 5 is made of a high refractive index material (1.9≤Nd5≤1.95), which optimizes the light refraction path through material properties, reduces lens thickness and improves aberration correction capability.

[0045] In the optical-mechanical lens module provided in the embodiments of this application, the S5 / TTL ratio (0.1 < S5 / TTL < 0.35) of the fifth lens 5 is related to the optical distortion control capability of the entire optical-mechanical lens module, and can make the optical distortion of the entire optical-mechanical lens module < 15%.

[0046] The optical-mechanical lens module provided in this application achieves a technological breakthrough by arranging five aspherical glass lenses with specific optical power distribution and refractive index range along the optical axis from the object side to the image side, resulting in an optical total length (TTL) of less than 12mm and a field of view (FOV) of 70° or more. The optical design provided in this application, while maintaining a compact structure (e.g., TTL less than 12mm), effectively overcomes the bottleneck of the FOV (Field of View) in existing full-color u-LED optical engine technology, which is difficult to exceed 65°, thus enhancing the user immersion of AR optical display devices. By optimizing lens combination and material selection, the optical length of the optical engine is significantly reduced compared to the traditional X-cube color combination scheme, effectively resolving the contradiction between the size of the optical engine and the field of view, and improving wearing comfort. In particular, the fifth lens 5 uses a high refractive index material (1.9≤Nd5≤1.95) and controls the ratio of its object-side sag to its total length (0.1<S5 / TTL<0.35), so that optical distortion can be controlled to a level of less than 15%, which significantly improves the image quality compared to the optical distortion of more than 20% in the traditional scheme, and solves the problem of edge image quality degradation at large field of view.

[0047] This application solves technical problems such as limited field of view, large size of optical engine lens module and poor imaging quality through a new optical architecture design, providing key technical support for the miniaturization and high performance development of AR optical display devices.

[0048] See some examples in this application. Figure 1 The focal length f5 of the fifth lens 5 satisfies: -200mm < f5 < -180mm; and the focal length f5 of the fifth lens 5 and the total focal length F of the optical engine lens module satisfy: 18 < |f5 / F| < 26.

[0049] The fifth lens 5 is designed as a concave lens with extremely low optical power, and its core feature is reflected in the synergistic optimization of focal length parameters and surface design: Focal length quantization constraint: The focal length f5 of the fifth lens is designed within the range of -200mm to -180mm, while simultaneously satisfying the ratio 18 < |f5 / F| < 26 (where F is the total focal length of the optical-mechanical lens module). This condition, through the high ratio of the absolute value of the large focal length to the total focal length F, ensures that the fifth lens exhibits a near-zero weak negative optical power characteristic, effectively avoiding excessive interference with the optical path.

[0050] Surface shape and thickness characteristics: The fifth lens 5 adopts a design where the center thickness and edge thickness are almost the same, forming a thin lens structure. This special surface shape, combined with low optical power characteristics, allows it to primarily perform the function of fine-tuning the beam path in the optical path; As the lens closest to the image side, the fifth lens achieves field curvature and astigmatism correction through the above design. At the same time, its weak negative optical power complements the positive optical power of the fourth lens 4, thus optimizing the systematic balance of aberrations across the entire field of view while maintaining the stability of the total optical power of the module.

[0051] In some examples of this application, the total focal length F of the optical engine lens module satisfies: 8.5mm < F < 9.0mm.

[0052] The optical engine lens module provided in this application embodiment has a total focal length F ranging from 8.5mm to 9.0mm. This focal length range, through controlling the optical power distribution of each lens and the optical path structure, effectively balances image quality, optical distortion, and the compactness of the module's optical structure while ensuring a 70° wide field of view (FOV). The optical engine lens module provided in this application embodiment provides a high-definition, low-distortion projection imaging foundation for AR optical display devices.

[0053] In some examples of this application, the center thickness of each lens in the optical-mechanical lens module satisfies: 2.2 < (T1 + T3 + T4) / (T2 + T5) < 2.6, where T1, T2, T3, T4, and T5 are the center thicknesses of the first lens 1 to the fifth lens 5, respectively.

[0054] The optical-mechanical lens module provided in this application optimizes optical performance by controlling the proportional relationship of the center thicknesses of each lens. Specifically, the center thicknesses of the first lens 1 to the fifth lens 5 are set to T1, T2, T3, T4, and T5, respectively, and their combined thickness must satisfy the constraint condition 2.2 < (T1 + T3 + T4) / (T2 + T5) < 2.6.

[0055] The proportional design in this example, by allocating the axial dimensions of positive power lenses (T1, T3, T4) and negative power lenses (T2, T5), forms an optical path structure with alternating optical powers, enabling the entire optical engine lens module to achieve efficient beam control with a 70° field of view (FOV) within an optical length of, for example, 11.5 mm.

[0056] Based on the center thickness relationship of each lens designed in this example of the application, at least the following technical effects can be achieved: Systematic aberration correction: Optimization of the thickness ratio of positive and negative lenses enables aberrations (such as spherical aberration and coma) to complement and cancel each other out in the optical path, increasing the peak value of the MTF curve across the entire field of view to over 0.6; Compact optical structure is ensured: In the short focal length design with a total focal length of 8.5mm~9.0mm, the center thickness ratio of each lens is reasonably controlled to avoid excessive stacking of lenses, ensuring that the axial dimension of the optical engine lens module is ≤12mm, which can fully meet the needs of lightweight AR optical display devices. Optical power distribution balance: By constraining the center thickness ratio, the total optical power of the positive lens group (T1+T3+T4) is matched with that of the negative lens group (T2+T5), controlling the optical distortion of the optical-mechanical lens module to <15%, and significantly improving the uniformity of edge image quality.

[0057] In some examples of this application, the center thickness T3 of the third lens 3 and the total optical length TTL of the optical-mechanical lens module satisfy: 15%≤T4 / TTL≤18%.

[0058] In the optomechanical lens module provided in this application embodiment, the third lens 3, as the core optical element in the middle section of the optical path, adopts a positive power glass aspherical design, and the ratio of its center thickness T3 to the total optical length TTL is limited to 15% to 18%. This ratio, by controlling the axial dimension of the third lens 3, ensures that it has sufficient light refraction capability to achieve beam convergence, and also provides a stable, low-aberration beam transmission basis for other lenses (such as the fifth lens), thereby ensuring the optical performance balance of the entire optomechanical lens module.

[0059] As one of the achromatic optical elements, the third lens 3, through the synergistic optimization of a medium refractive index material (1.48≤Nd3≤1.59) and the curvature of an aspherical surface, specifically corrects axial and lateral chromatic aberration at large field of view (FOV≥70°). Its continuously varying aspherical curvature design effectively eliminates color separation caused by optical path difference, ensuring consistent color reproduction of white light imaging across the entire field of view, while avoiding image quality degradation caused by excessive chromatic aberration correction.

[0060] The third lens 3, through the optimization of the proportion of the center thickness T3 and the matching design with the material refractive index, achieves good control of color difference and significantly improves the color uniformity of the entire field of view.

[0061] A center thickness T3 ratio of 15% to 18% ensures that the third lens 3 can fully converge light within a limited space, providing other lenses with low aberration and high uniformity incident beams, and avoiding beam divergence or excessive convergence due to insufficient thickness.

[0062] In a short-focal-length optical structure with a total optical length TTL≤12mm, the center thickness ratio of the third lens 3 is designed to balance optical performance with the axial dimensions of the optical-mechanical lens module, adapting to the installation requirements of lightweight AR glasses, while reducing reliance on subsequent correction elements through achromatic aberration function.

[0063] See some examples in this application. Figure 2 The angle between the tangent on the image side of the third lens 3 at its maximum aperture and the optical axis is A1, and the angle between the tangent on the object side at its maximum aperture and the optical axis is A2, and the angles satisfy the following angular relationships: 30°<|A1-A2|<60°, and 1.7<|A2 / A1|<2.3.

[0064] In the optical-mechanical lens module provided in this application embodiment, the third lens 3 is located in the middle section of the optical-mechanical lens module. The angle between the tangent of its image-side surface (the surface near the image side) and object-side surface (the surface near the object side) at the maximum aperture and the optical axis is optimized to be: 30° < |A1-A2| < 60° (angle difference range) and 1.7 < |A2 / A1| < 2.3 (angle ratio range). This design, through the adjustment of the curvature of the aspherical surface, enables the tilt angles of the two surfaces of the third lens 3 to form a differentiated match.

[0065] Regarding the angle difference control, i.e., 30° < |A1-A2| < 60°: This ensures that the light undergoes a gradual refraction within the third lens 3, avoiding a surge in aberrations caused by abrupt changes in angle on one side, while enhancing the control of edge light rays with a large field of view (FOV ≥ 70°) through a large angle difference.

[0066] Regarding the angle ratio control, i.e., 1.7 < |A2 / A1| < 2.3: the curvature distribution ratio of the object side and the image side of the third lens 3 is optimized so that the third lens 3 can effectively balance the correction intensity of axial chromatic aberration and coma while maintaining positive optical power, and prevent local image quality degradation caused by excessive curvature on one side.

[0067] In addition, the angular constraint in this example of the application, together with the glass material (refractive index 1.48≤Nd3≤1.59) and the center thickness ratio (15%≤T3 / TTL≤18%) of the third lens 3, form a synergistic design to jointly constitute the optical basis for achromatic and aberration correction.

[0068] Based on the optical parameters of the third lens 3 provided in this example of the application, through optimized design of the angle difference and angle ratio, the third lens 3 significantly improves image quality uniformity in a 70° field of view. The angle design, combined with a medium refractive index material, significantly reduces chromatic aberration. The angle ratio control ensures a smooth transition of curvature on both sides of the third lens 3, reducing light reflection loss at the lens interface, improving light efficiency, and simultaneously reducing the risk of stray light caused by angle mismatch.

[0069] The optical solution of this application, within an optical length of 11.5mm, avoids excessive bending of the third lens 3 through the coordinated design of angle constraints and center thickness ratio, ensuring that the axial dimension of the optical engine lens module is significantly reduced compared to similar solutions, and can adapt to the requirements of lightweight AR optical display devices.

[0070] In some examples of this application, the center thickness T4 of the fourth lens 4 and the total optical length TTL of the optical-mechanical lens module satisfy: 7%≤T4 / TTL≤10%.

[0071] In the optical-mechanical lens module provided in this application embodiment, the fourth lens 4, as a positive optical power optical element near the image side in the optical-mechanical lens module, has its center thickness T4 optimized to a ratio of 7% to 10% to the total optical length TTL of the entire optical-mechanical lens module. This ratio, through precise control of the axial (optical axis) dimension of the fourth lens 4, ensures that it has sufficient light refraction capability to correct residual aberrations, while avoiding excessive optical length of the module or a decrease in light transmission efficiency due to excessive center thickness.

[0072] As one of the key optical components for achromatic and aberration correction, the fourth lens 4 adopts a glass aspherical design. Its central thickness T4 ratio is optimized in conjunction with the material refractive index (1.48≤Nd4≤1.59) and surface curvature to effectively balance field curvature, distortion and chromatic aberration under a large field of view (FOV≥70°), while providing a low-aberration beam transmission basis for other components.

[0073] In this application, the fourth lens 4 is designed with a center thickness ratio of 7%-10%, which enables low optical distortion (<15%) correction within a limited axial space, thereby increasing the MTF peak value of the entire field of view to 0.6 or above and significantly enhancing the edge image quality clarity.

[0074] The aspherical design of the fourth lens 4 matches its center thickness T4, effectively suppressing various aberrations under a large field of view and ensuring the geometric fidelity of the final projected image.

[0075] The fourth lens 4 and the third lens 3 form a complementary achromatic system through functional division and synergistic optimization of the center thickness ratio.

[0076] In the optomechanical lens module provided in this application embodiment, a center thickness ratio of 7%-10% ensures that the fourth lens 4 has stable light-converging capability in the optical path, avoiding beam divergence or excessive convergence due to insufficient thickness. In an optical structure maintaining a total optical length (TTL) ≤ 12mm, the center thickness ratio of the fourth lens 4 balances optical performance and axial dimensions. This enables the optomechanical lens module to achieve a balance between small size, large field of view, and high-quality imaging.

[0077] In some examples of this application, the object side of the fourth lens 4 has a sagitta of S3 at the maximum aperture, and the image side has a sagitta of S4 at the maximum aperture, satisfying: 3.5 < S3 / S4 < 4.2.

[0078] In the optical-mechanical lens module provided in this application embodiment, the sag of the object-side surface (the surface near the object side) and the image-side surface (the surface near the image side) of the fourth lens 4 at the maximum aperture is optimized to satisfy the relationship: 3.5 < S3 / S4 < 4.2. This design, through the differentiated allocation of aspherical curvature, can achieve the following functions: The larger S3 (relative to S4) gives the object side a steeper curvature change, enhancing the ability to converge light rays at the edge of a large field of view (FOV≥70°), while the aspherical design corrects field curvature and distortion. A smaller S4 makes the curvature of the image side relatively gentle, reducing the reflection loss of light at the incident interface and reducing aberrations caused by excessive curvature.

[0079] In addition, the range of 3.5 < S3 / S4 < 4.2 ensures a smooth transition of curvature between the two surfaces of the fourth lens 4, avoiding over- or under-correction of aberrations due to proportional imbalance, while balancing the manufacturing difficulty and optical performance of the lens.

[0080] See some examples in this application. Figure 3The angle between the tangent on the image side of the fourth lens at its maximum aperture and the optical axis is A3, and the angle between the tangent on its object side at its maximum aperture and the optical axis is A4, satisfying the following angular relationships: 10° < |A3-A4| < 30°, and 0.7 < |A3 / A4| < 1.5.

[0081] In the optical-mechanical lens module provided in this application embodiment, the angle between the tangent of the fourth lens 4 at its maximum aperture and the optical axis (the surface near the image side) and the object side (the surface near the object side) is optimized as follows: The angular difference range satisfies 10° < |A3-A4| < 30°. This design ensures that the tilt angles of the two surfaces of the fourth lens 4 form a moderate difference, avoiding a surge in aberrations caused by abrupt changes in angle on one side.

[0082] The angle ratio range satisfies 0.7 < |A3 / A4| < 1.5. This design can balance the curvature intensity of the two surfaces of the fourth lens 4, prevent chromatic aberration correction failure due to excessively steep or gentle angles on one side, and optimize beam transmission stability.

[0083] In some examples of this application, the object side of the second lens 2 has a sagitta of S1 at the maximum aperture, and the image side has a sagitta of S2 at the maximum aperture, satisfying: 2.4 < S2 / S1 < 2.7.

[0084] In the optical-mechanical lens module provided in this application embodiment, an optimized design for the sagittal ratio of the second lens 2 is proposed: the sagittal of the object-side surface (the surface near the object side) at the maximum aperture is S1, and the sagittal of the image-side surface (the surface near the image side) at the maximum aperture is S2, satisfying 2.4 < S2 / S1 < 2.7. As a negative optical power element, the second lens has an image-side sagittal S2 that is 2.4-2.7 times the object-side sagittal S1, resulting in a steeper curvature change on the image side. This design can correct the residual field curvature on the object-side surface due to its gentle curvature, while significantly reducing optical distortion through aspherical design.

[0085] In conjunction with other lenses (such as the third lens 3 and the fourth lens 4, both of which are positive optical power), the optical distortion of the optical engine lens module is less than 15%, which meets the requirements of AR display for geometric shape fidelity.

[0086] In this example of the application, the sag-height ratio is optimized, which increases the amount of chromatic aberration (LCA) correction of the second lens 2. Combined with the chromatic aberration compensation design of other lenses, the overall chromatic aberration correction of the module is significantly improved, ensuring the color reproduction consistency of the full-color u-LED optical engine.

[0087] While maintaining optical performance, the height ratio optimization reduces the axial thickness (thickness along the optical axis) of the second lens, providing key support for compressing the overall optical length of the optical-mechanical lens module and adapting to the requirements of AR glasses for thinness and lightness.

[0088] In some examples of this application, the total optical length (TTL) of the optical-mechanical lens module is equal to the maximum aperture (D) of all lenses. max The ratio satisfies: 1.05 < TTL / D max <1.4.

[0089] In the optical-mechanical lens module of this application embodiment, the total optical length TTL and the maximum lens aperture D are... max The ratio (for example, the fifth lens 5) satisfies 1.05 < TTL / D max <1.4, the technical effect is: Compact design: By constraining TTL and the fifth lens aperture (D max The ratio of TTL to Dmax is 1.05 (1.05 < TTL / Dmax < 1.4). The aperture of the fifth lens (located on one side of the display unit 7) is matched with the total optical length of the module to avoid the axial dimension expansion of the module due to excessive aperture, or the excessive incident angle of light and aberration deterioration due to excessive aperture, thereby achieving a highly compact optical structure of the module.

[0090] Aberration correction optimization: The fifth lens 5, as an element that receives and transmits projected light, features a large aperture design (D... max It can project a large amount of light into the optical engine lens module.

[0091] The aspect ratio range provided in this example, through optical aperture optimization of the fifth lens 5, balances module compactness, image quality, light efficiency, and mass production cost, providing key design support for the high performance and commercialization of large FOV (70°) AR lenses.

[0092] See some examples in this application. Figure 1 The optical engine lens module further includes an aperture stop 6 and a display unit 7; wherein, the aperture stop 6 is located on the object side of the first lens 1; and the display unit 7 is located on the image side of the fifth lens 5 and is used to emit projection light.

[0093] Wherein, the aperture stop 6 is a front aperture stop, which is located on the object side of the first lens 1, that is, at the junction of the first lens 1 and the external diffraction waveguide device ( Figure 1The optical path between the coupling regions (not shown in the diagram). The pre-aperture, as a key optical control component, 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 6 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.

[0094] In the optical-mechanical lens module of this application, the display unit 7 is located on the image side of the fifth lens 5, and it emits full-color projection light instead of using a scheme of combining three RGB monochrome panels.

[0095] This application uses a single full-color panel as the display unit 7, and optimizes the ratio of the optical aperture of the fifth lens to the total optical length TTL of the module (1.05 < TTL / D). max <1.4), achieving a balance between compactness, image quality, light efficiency, and cost in the optical engine lens module. Compared to color mixing solutions, this design is more suitable for the needs of 70° ultra-large FOV AR lenses, providing a key technological path for the commercialization of full-color u-LED optical engines.

[0096] In a preferred embodiment, the optical structure of the optical engine lens module can be found in [reference needed]. Figure 1 The effective focal lengths of the first lens 1 to the fifth lens 5 in this optical engine lens module are shown in Table 1 below: Table 1

[0097] The first lens 1, the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 5 are glass aspherical lenses; The detailed optical parameters of the optical engine lens module are shown in Tables 2 and 3 below. Table 3 shows the aspherical design of each aspherical lens in Table 2.

[0098] Table 2

[0099] Table 3

[0100] In the specific example above, the main parameters of the optical-mechanical lens module design include: a total focal length F of 8.738mm; a field of view (FOV) of 70°; a sagitta of the object-side surface of the fifth lens at its maximum aperture of S5 = 3.2757mm; an entrance pupil diameter of 2.6mm and an entrance pupil distance of 0.1mm; a pixel size of 5.62μm; an image plane size of 10mm~11mm; and optical distortion <15%. (See [reference needed]). Figure 4 The operating wavelength is 460nm~618nm. High-quality output with an MTF value >0.6@89lp / mm is achieved within the 460nm-618nm band. See [link / reference]. Figure 5 .

[0101] The optical-mechanical lens module provided in this application achieves the following core beneficial effects through the optimized design of a single full-color panel and five glass aspherical lenses: The module's total optical length (TTL) is only 11.5mm, and the module's maximum aperture is 10.2mm. This is achieved through a constraint on the ratio of TTL to the fifth lens aperture (1.05 < TTL / D). max <1.4), significantly reducing module size and adapting to the lightweight requirements of AR glasses.

[0102] The module controls optical distortion to within 15% across the entire field of view, efficiently corrects aberrations such as field curvature, and ensures imaging uniformity under a 70° ultra-large FOV.

[0103] Regarding the effective focal lengths of each lens shown in Table 1 above, the focal length ranges for the first lens 1 to the fifth lens 5 are as follows: 9.3mm < f1 < 10.3mm; -7.3mm < f1 < -6.3mm; 6.5mm < f3 < 7.5mm; -20mm < f4 < -16mm; -200mm < f5 < -180mm.

[0104] The optical-mechanical lens module of this application will be described below through Examples 1 to 3.

[0105] Example 1 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: Aperture 6 is the front aperture; The first lens 1 has positive optical power; The second lens 2 has negative optical power; The third lens 3 has positive optical power; The fourth lens 4 has positive optical power; The fifth lens 5 has negative optical power; and, Display unit 7 is used to provide projection light; Among them, the first lens 1 to the fifth lens 5 are all glass aspherical lenses.

[0106] The optical parameters of the optomechanical lens module shown in this embodiment 1 are shown in Tables 4 and 5 below. Table 5 shows the aspherical design of each aspherical lens in Table 4.

[0107] Table 4

[0108] Table 5

[0109] For the optical-mechanical lens module provided in Embodiment 1, the sagitta of the object-side surface of the fifth lens at its maximum aperture is S5 = 3.2741 mm. See also Figure 7 , Figure 7 The modulation transfer function diagram of the optical-mechanical lens module is shown below. Figure 7 It can be seen that MTF > 0.6 @ 89lp / mm.

[0110] Example 2 See Figure 8 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: Aperture 6 is the front aperture; The first lens 1 has positive optical power; The second lens 2 has negative optical power; The third lens 3 has positive optical power; The fourth lens 4 has positive optical power; The fifth lens 5 has negative optical power; and, Display unit 7 is used to provide projection light; Among them, the first lens 1 to the fifth lens 5 are all glass aspherical lenses.

[0111] The optical parameters of the optomechanical lens module shown in this embodiment 2 are shown in Tables 6 and 7 below. Table 7 shows the aspherical design of each aspherical lens in Table 6.

[0112] Table 6

[0113] Table 7

[0114] For the optical-mechanical lens module provided in Embodiment 2, the sagitta of the object-side surface of the fifth lens at its maximum aperture is S5 = 3.2719 mm. See also... Figure 9 , Figure 9 The modulation transfer function diagram of the optical-mechanical lens module is shown below. Figure 9 It can be seen that MTF > 0.6 @ 89lp / mm.

[0115] Example 3 See Figure 10 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: Aperture 6 is the front aperture; The first lens 1 has positive optical power; The second lens 2 has negative optical power; The third lens 3 has positive optical power; The fourth lens 4 has positive optical power; The fifth lens 5 has negative optical power; and, Display unit 7 is used to provide projection light; Among them, the first lens 1 to the fifth lens 5 are all glass aspherical lenses.

[0116] The optical parameters of the optomechanical lens module shown in this embodiment 3 are shown in Tables 8 and 9 below. Table 9 shows the aspherical design of each aspherical lens in Table 8.

[0117] Table 8

[0118] Table 9

[0119] For the optical-mechanical lens module provided in Embodiment 3, the sagitta of the object-side surface of the fifth lens at its maximum aperture is S5 = 3.2688 mm. See also 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 > 0.6 @ 89lp / mm.

[0120] The optical distortion of the optical engine lens modules provided in Embodiments 1 to 3 above is less than 15%.

[0121] 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 6 of the optical engine lens module matches the entrance pupil diameter of the optical waveguide device.

[0122] 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.

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

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

Claims

1. 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) has positive optical power; The second lens (2) has negative optical power; The third lens (3) has positive optical power and its refractive index Nd3 is 1.48≤Nd3≤1.59; The fourth lens (4) has positive optical power; and, The fifth lens (5) has negative optical power and its refractive index Nd5 is 1.9≤Nd5≤1.95; The first lens (1) to the fifth lens (5) are all aspherical glass lenses; The total optical length (TTL) of the optical engine lens module is less than 12 mm. The object side of the fifth lens (5) has a sagitta of S5 at the maximum aperture, and satisfies the relationship: 0.1 < S5 / TTL < 0.

35.

2. The optical-mechanical lens module according to claim 1, characterized in that, The focal length f5 of the fifth lens (5) satisfies: -200mm < f5 < -180mm; and the focal length f5 of the fifth lens (5) and the total focal length F of the optical engine lens module satisfy: 18 < |f5 / F| < 26.

3. The optical-mechanical lens module according to claim 2, characterized in that, The total focal length F of the optical engine lens module satisfies: 8.5mm < F < 9.0mm.

4. The optical-mechanical lens module according to claim 1, characterized in that, The center thickness of each lens in the optical-mechanical lens module satisfies: 2.2 < (T1 + T3 + T4) / (T2 + T5) < 2.6, where T1, T2, T3, T4, and T5 are the center thicknesses of the first lens (1) to the fifth lens (5), respectively.

5. The optical-mechanical lens module according to any one of claims 1-4, characterized in that, The center thickness T3 of the third lens (3) and the total optical length TTL of the optical-mechanical lens module satisfy the following condition: 15%≤T4 / TTL≤18%.

6. The optical-mechanical lens module according to claim 5, characterized in that, The third lens (3) has an image-side tangent at its maximum aperture with an angle of A1 and an object-side tangent at its maximum aperture with an angle of A2, and satisfies the following angular relationships: 30° < |A1-A2| < 60° and 1.7 < |A2 / A1| < 2.

3.

7. The optical-mechanical lens module according to any one of claims 1-4, characterized in that, The center thickness T4 of the fourth lens (4) and the total optical length TTL of the optical-mechanical lens module satisfy the following condition: 7%≤T4 / TTL≤10%.

8. The optical-mechanical lens module according to claim 7, characterized in that, The fourth lens (4) has an object side elevation of S3 at the maximum aperture and an image side elevation of S4 at the maximum aperture, and satisfies: 3.5 < S3 / S4 < 4.

2.

9. The optical-mechanical lens module according to claim 7, characterized in that, The angle between the tangent on the image side of the fourth lens (4) at the maximum aperture and the optical axis is A3, and the angle between the tangent on the object side at the maximum aperture and the optical axis is A4, and the angle relationship is satisfied: 10°<|A3-A4|<30°, and 0.7<|A3 / A4|<1.

5.

10. The optical-mechanical lens module according to any one of claims 1-4, characterized in that, The second lens (2) has an object side elevation of S1 at the maximum aperture and an image side elevation of S2 at the maximum aperture, and satisfies: 2.4 < S2 / S1 < 2.

7.

11. The optical-mechanical lens module according to claim 1, characterized in that, The total optical length TTL of the optical engine lens module is equal to the maximum aperture D of all lenses. max The ratio satisfies: 1.05 < TTL / D max <1.

4.

12. The optical-mechanical lens module according to claim 1, characterized in that, The optical-mechanical lens module also includes: Aperture (6) is located on the object side of the first lens (1); and The display unit (7) is located on the image side of the fifth lens (5) and is used to emit projection light.

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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