Optical-mechanical lens module and assembly method thereof

Abstract

The application discloses an optical-mechanical lens module and an assembling method thereof. The optical-mechanical lens module comprises, in sequence from an object side to an image side, a lens group, a color combining prism and a field lens group. The lens group comprises a first lens group and a second lens group arranged in sequence from the object side to the image side. The first lens group has a negative focal length and comprises at least two lenses with a negative focal length. The second lens group has a positive focal length and comprises at least two lenses with a positive focal length. The field lens group comprises three field lenses with a negative focal length. The three field lenses are fixed to three incident surfaces of the color combining prism through an active calibration process. The focal length of the optical-mechanical lens module is F, the focal length of each field lens in the field lens group is F2, and the two satisfy the condition: -1.1 < F2 / F < -0.9. Through specific negative focal length distribution and differential physical assembly gap, the optical-mechanical lens module can balance the large field of view, high image quality and high yield in mass production without demanding the limit machining precision of parts.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, specifically to an optical-mechanical lens module and its assembly method. Background Technology

[0002] With the development of augmented reality (AR) technology, the applications of near-eye display devices are becoming increasingly diversified. Key indicators such as image quality, weight, and size of near-eye display devices directly affect user comfort when wearing them. As the core imaging component of near-eye display devices, the optical engine module faces increasingly stringent market demands: it must achieve high brightness, a wide field of view, and superior image quality within a small size and weight. Therefore, it is necessary to rationally allocate the surface shape and optical power of each lens within the optical engine module, as well as to arrange the positional relationships of the lenses appropriately.

[0003] For existing near-eye display devices, achieving a large field of view requires shortening the focal length of the optical-mechanical module and receiving large-angle light rays emitted by the display chip. However, short focal lengths and large-angle light rays significantly increase astigmatism, field curvature, distortion, and transverse chromatic aberration at the edges of the field of view, leading to a sharp decline in the image quality of the optical-mechanical module. Furthermore, near-eye devices place high demands on the overall optical length and radial dimensions of the optical-mechanical module; the aperture of the lenses and the spacing between lenses cannot be arbitrarily increased, further compressing the space available for aberration correction within the module. Therefore, existing optical-mechanical modules struggle to achieve a balance between a large field of view, short overall length, small aperture, and high image quality.

[0004] Furthermore, to achieve full-color display, the optical engine module typically uses a color-combining prism to merge the light paths of multiple monochromatic channels (such as red, green, and blue). In the aforementioned compact design with a large field of view and short focal length, lenses often need to be endowed with high optical power to correct aberrations as much as possible. However, the high optical power design makes the entire optical system extremely sensitive to manufacturing and assembly tolerances (such as lens thickness, prism surface shape, and angular errors). At the same time, different wavelengths of light have inherent chromatic aberrations in the medium, making it difficult for the actual focal planes of each channel to perfectly coincide. Under existing conventional assembly processes, this accumulation of tolerances among multiple components and the difference in focal planes among multiple channels are difficult to effectively absorb, ultimately leading to problems such as decreased edge resolution and poor color convergence in mass-produced products, severely restricting the actual mass production yield of high-quality optical engine modules. Summary of the Invention

[0005] One objective of this application is to provide an optical-mechanical lens module that solves the technical problems of existing optical-mechanical modules being unable to simultaneously achieve high edge image quality under a large field of view, and the inability to accurately align the focal planes of each color light due to the accumulation of tolerances during multi-channel color combining.

[0006] Another objective of this application is to provide a method for assembling an optical-mechanical lens module.

[0007] To achieve at least one of the above objectives, the technical solution adopted in this application is: an optical-mechanical lens module, which includes, from the object side to the image side, a lens group, a color combining prism, and a field lens group; The lens group includes a first lens group and a second lens group arranged sequentially from the object side to the image side. The first lens group has negative optical power and includes at least two lenses with negative optical power. The second lens group has positive optical power and includes two lenses with positive optical power. The field lens assembly includes three negative power field lenses. The three field lenses are respectively fixed to the three incident surfaces of the color combining prism by adhesive layers. Each of the three field lenses and its corresponding incident surface has an adhesive gap, and at least two of the adhesive gaps are different in size. The adhesive gaps are formed by an active calibration process, which is an adjustment of the relative position between the field lenses and the color combining prism based on the actual imaging results of the optical engine lens module. Wherein, the focal length of the optical-mechanical lens module is F, and the focal length of each field lens in the field lens group is F2, and the two satisfy: -1.1 <F2 / F<-0.9。

[0008] To achieve at least one of the above objectives, the technical solution adopted in this application is: a method for assembling an optical-mechanical lens module, wherein the optical-mechanical lens module includes a lens group, a color combining prism, and a field lens group, wherein the field lens group includes three field lenses, and the three field lenses respectively correspond to three primary color light sources: green, blue, and red. The method includes the following steps: S1 Initial Positioning: Pre-position and initially align the three field lenses with the three incident surfaces of the color combining prism; S2 Active Calibration: Based on the actual imaging results of the optical-mechanical lens module, the relative positions and / or attitudes between the three field lenses and their corresponding incident surfaces are adjusted respectively so that the imaging quality of each optical path meets the preset requirements; after adjustment, an adhesive gap is formed between the three field lenses and their corresponding incident surfaces, and at least two of the adhesive gaps are different in size. S3 Curing: The three field lenses, after active calibration, are bonded and fixed to the color combining prism.

[0009] Compared with the prior art, the beneficial effects of this application are as follows: (1) By introducing a field lens group between the light-emitting chip and the color-combining prism, the principal ray angle is effectively compressed, causing the principal surface of the lens group to move towards the light-emitting chip, effectively shortening the working distance of the rear group. This reduces the overall length of the optical system while maintaining the field curvature and lateral chromatic aberration correction capabilities. This improvement provides significant space leeway for the structural design of small near-eye display devices. Furthermore, thanks to the effective convergence and aberration balance of the edge field of view by the field lens group, the problem of vignetting at the edges under a large field of view is improved. Tests show that the relative illumination of this optical-mechanical lens module remains stable at over 70% within a 50° full field of view, thus providing users with a uniform and comfortable visual experience across the entire field of view. While ensuring a short overall length and a large field of view, the optical-mechanical lens module still possesses extremely high imaging quality. Within the core 40° field of view, the MTF characteristic curves of the RGB three-color channels at a spatial frequency of 200 lp / mm are all better than 0.55. The optical-mechanical lens module ensures extremely high center and edge contrast while balancing ultra-short focal length and a large field of view.

[0010] (2) This application effectively suppresses field curvature and distortion under short focal length and large field of view by designing a negative optical power field lens that satisfies a specific focal length ratio. At the same time, by utilizing the differentiated assembly gap between the field lens and the color combining prism, the tolerance accumulation and multi-channel focal plane differences caused by strong optical power are actively absorbed at the physical level. This solution perfectly balances the extreme compactness of the optical engine, the large field of view and high image quality, and the high yield of mass production without demanding the extreme machining accuracy of the parts. Attached Figure Description

[0011] Figure 1 This is a structural diagram of the optical engine lens module.

[0012] Figure 2A This is a structural diagram of the optical lens in the green light path of the optical-mechanical lens module in Example 1.

[0013] Figure 2B This is a structural diagram of the optical lens in the blue light path of the optical-mechanical lens module in Example 1.

[0014] Figure 2C This is a structural diagram of the optical lens in the red light path of the optical-mechanical lens module in Example 1.

[0015] Figure 3A The MTF characteristic curve of the green light path in the optical-mechanical lens module of Example 1 is shown.

[0016] Figure 3B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 1 is shown.

[0017] Figure 3C The MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 1 is shown.

[0018] Figure 4A The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 1 at a frequency of 200 lp / mm at -10℃ is shown.

[0019] Figure 4B The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 1 at a frequency of 200 lp / mm and a temperature of 20°C is shown.

[0020] Figure 4C The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 1 at a frequency of 200 lp / mm and a temperature of 60°C is shown.

[0021] Figure 5A The astigmatism curve is for the optical-mechanical lens module of Example 1.

[0022] Figure 5B The distortion curve is for the optical-mechanical lens module of Example 1.

[0023] Figure 5C The image shows the relative illumination curve of the optical-mechanical lens module in Example 1.

[0024] Figure 6 This is a structural diagram of the optical lens in the green light path of the optical-mechanical lens module in Example 2.

[0025] Figure 7A The MTF characteristic curve of the green light path in the optical-mechanical lens module of Example 2 is shown.

[0026] Figure 7B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 2 is shown.

[0027] Figure 7C The image shows the MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 2.

[0028] Figure 8A The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 2 at a frequency of 200 lp / mm at -10℃ is shown.

[0029] Figure 8B The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 2 at a frequency of 200 lp / mm and a temperature of 20°C is shown.

[0030] Figure 8C The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 2 at a frequency of 200 lp / mm and a temperature of 60°C is shown.

[0031] Figure 9A The astigmatism curve is for the optical-mechanical lens module of Example 2.

[0032] Figure 9BThe distortion curve is for the optical-mechanical lens module of Example 2.

[0033] Figure 9C The image shows the relative illumination curve of the optical-mechanical lens module in Example 2.

[0034] Figure 10 This is a structural diagram of the optical lens in the green light path of the optical-mechanical lens module in Example 3.

[0035] Figure 11A The MTF characteristic curve of the green light path in the optical-mechanical lens module of Example 3 is shown.

[0036] Figure 11B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 3 is shown.

[0037] Figure 11C The MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 3 is shown.

[0038] Figure 12A The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 3 at a frequency of 200 lp / mm at -10℃ is shown.

[0039] Figure 12B The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 3 at a frequency of 200 lp / mm and a temperature of 20°C is shown.

[0040] Figure 12C The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 3 at a frequency of 200 lp / mm and a temperature of 60°C is shown.

[0041] Figure 13A The astigmatism curve is for the optical-mechanical lens module of Example 3.

[0042] Figure 13B The distortion curve is for the optical-mechanical lens module of Example 3.

[0043] Figure 13C The image shows the relative illumination curve of the optical-mechanical lens module in Example 3.

[0044] Figure 14 This is a structural diagram of the optical lens in the green light path of the optical-mechanical lens module in Example 4.

[0045] Figure 15A The MTF characteristic curve of the green light path in the optical-mechanical lens module of Example 4 is shown.

[0046] Figure 15B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 4 is shown.

[0047] Figure 15CThe MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 4 is shown.

[0048] Figure 16A The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 4 at a frequency of 200 lp / mm at -10℃ is shown.

[0049] Figure 16B The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 4 at a frequency of 200 lp / mm and a temperature of 20°C is shown.

[0050] Figure 16C The MTF defocusing characteristic curve of the green light path in the optical-mechanical lens module of Example 4 at a frequency of 200 lp / mm and a temperature of 60°C is shown.

[0051] Figure 17A The astigmatism curve is for the optical-mechanical lens module of Example 4.

[0052] Figure 17B The distortion curve is for the optical-mechanical lens module of Example 4.

[0053] Figure 17C The relative illumination curve is for the optical-mechanical lens module of Example 4.

[0054] In the figure: 1. First lens; S2. Object-side surface of the first lens; S3. Image-side surface of the first lens; 2. Second lens; S4. Object-side surface of the second lens; S5. Image-side surface of the second lens; 3. Third lens; S6. Object-side surface of the third lens; S7. Image-side surface of the third lens; 4. Fourth lens; S8. Object-side surface of the fourth lens; S9. Image-side surface of the fourth lens; 5. Fifth lens; S10. Object-side surface of the fifth lens; S11. Image-side surface of the fifth lens; 6. Field lens; 6a. First field lens; 6b. Second field lens; 6c. Third field lens; S14. Object-side surface of the field lens; S15. Image-side surface of the field lens; 7. Color combining prism; S12. Object-side surface of the color combining prism; S13. Image-side surface of the color combining prism. Detailed Implementation

[0055] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0056] In the description of this application, it should be noted that the directional terms such as center, horizontal, vertical, length, width, thickness, up, down, front, back, left, right, vertical, horizontal, top, bottom, inside, outside, clockwise, counterclockwise, etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0057] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0058] The terms used in the specification and claims of this application include and have, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are expressly listed, but may include other steps or units that are not expressly listed or that are inherent to such process, method, product or device.

[0059] It should be noted that the shapes of the spherical or aspherical surfaces shown in the accompanying drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not drawn strictly to scale.

[0060] It should be noted that if the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. When projection lenses are used in devices such as VR and AR, the surface of each lens closest to the human eye is called the object-side surface of the lens, and the surface of each lens closest to the display chip is called the image-side surface of the lens.

[0061] The optical engine lens module provided in this application embodiment can be applied to various optical imaging and projection systems, such as augmented reality (AR) devices for near-eye display, head-up display (HUD) systems, micro projectors (Pico-Projectors), or other electronic devices that require a compact, high-quality optical engine. This application embodiment does not limit the specific application scenarios and forms of the optical engine lens module.

[0062] According to one embodiment of this application, an optical-mechanical lens module is provided, which has a lens group, a color combining prism and a field lens group arranged sequentially from the object side to the image side.

[0063] like Figure 1As shown, the lens group includes a first lens group and a second lens group arranged sequentially from the object side to the image side. The first lens group has negative optical power and includes at least two lenses with negative optical power. The second lens group has positive optical power and includes two lenses with positive optical power. The color combining prism can preferably be implemented as an X-Cube prism, which has three incident surfaces and one exit surface; The field lens assembly consists of three field lenses with negative optical power, which are fixed to the three incident surfaces of the color combining prism by adhesive layers.

[0064] This optical-mechanical lens module is used in display or projection systems that combine multiple colors of light. This multiple color light is provided by a light-emitting component (such as a light-emitting chip), and is typically red, blue, and green light, i.e., R, G, and B three-channel color light. Three field lenses 6 each correspond to one channel of color light. The monochromatic beams of each channel, after passing through their respective field lenses, enter the interior of the color-combining prism 7 from its three incident surfaces. After reflection or transmission through the internal dichroic film system, they converge into a single coaxial colored beam and exit from the exit surface, passing through a lens group after exiting the prism.

[0065] Bonding gaps are formed between the incident surfaces of the three field lenses 6 and their corresponding color-combining prisms 7, and at least two of these gaps are of different sizes. These gaps are formed by an active calibration process, which adjusts the relative positions of each field lens 6 and the color-combining prism 7 based on the actual imaging results of the optical-mechanical lens module. The final value of the bonding gap is not the design nominal value, but a compensation value that matches the actual aberration state of the specific module, thereby correcting the back focus, field curvature, eccentricity, and tilt errors of each optical path. For the specific steps of this active calibration process, please refer to the embodiments describing the optical-mechanical lens module assembly method later in the text; they will not be repeated here.

[0066] In one embodiment, the first lens group of the above-mentioned lens group includes three lenses, which are, in order from the object side to the image side along the optical axis, a first lens 1 with negative optical power, a second lens 2 with positive optical power, and a third lens 3 with negative optical power. The second lens group includes two lenses, which are, in order from the object side to the image side along the optical axis, a fourth lens 4 with positive optical power and a fifth lens 5 with positive optical power.

[0067] When light passes through the color-combining prism 7 in the optical path and enters the five lenses of the lens group, from the image side to the object side, it passes sequentially through the fifth lens 5 (positive optical power), the fourth lens 4 (positive optical power), the third lens 3 (negative optical power), the second lens 2 (positive optical power), and the first lens 1 (negative optical power). The positive-positive-negative-positive-negative optical power sequence of the five lenses, together with the negative optical power field lens, constitutes the core optical architecture for achieving light control and aberration correction.

[0068] In this embodiment, the field lens 6 is a plastic aspherical lens with negative optical power. The object-side surface S14 of the field lens is concave, and the image-side surface S15 is convex. The main function of the field lens 6 is to receive the large-angle diverging light beam from the light-emitting chip (e.g., a Micro-OLED microdisplay) and perform preliminary convergence and aberration pre-correction. The field lens 6 can bend the principal ray, causing the principal surface of the lens group to move towards the light-emitting chip, effectively shortening the working distance of the rear group. Thus, while maintaining the system's field curvature and transverse chromatic aberration correction capabilities, it effectively compresses the total length (TTL) of the optical system.

[0069] The color-combining prism 7 is positioned between the outgoing light path of the field lens group and the incoming light path of the lens group. It physically separates the two lens groups, and its main function is to combine light beams from different directions.

[0070] In the lens group, the first lens 1, the third lens 3, the fourth lens 4 and the fifth lens 5 are all plastic aspherical lenses, and the second lens 2 is a glass aspherical lens.

[0071] The fifth lens 5 has positive optical power. Its object-side surface S10 and image-side surface S11 are both concave. As the first lens in the lens group to receive light from the color-combining prism, the fifth lens 5 is responsible for converging the light rays.

[0072] The fourth lens 4 has positive optical power. Its object-side surface S8 is convex, and its image-side surface S9 is concave. The function of the fourth lens 4 is similar to that of the fifth lens 5; these two lenses provide the main positive optical power for the entire optical system and converge the light rays from the color-combining prism. Simultaneously, they utilize the properties of their plastic material to compensate for temperature drift, correcting on-axis chromatic aberration, astigmatism, and field curvature in the optical system.

[0073] The third lens 3 has negative optical power. The object-side surface S6 of the third lens is convex, and the image-side surface S7 of the third lens is also convex. The main function of the third lens 3 is to provide negative optical power to balance the aberrations produced by the fourth lens 4 and the fifth lens 5, especially for effectively correcting distortions in the optical system.

[0074] The second lens 2 has positive optical power. The object-side surface S4 of the second lens is convex, and the image-side surface S5 of the second lens is concave. The second lens 2 works in conjunction with the first lens 1 and the third lens 3 to further smooth and converge the light beam, mainly for correcting spherical aberration and coma in the optical system under large field of view.

[0075] The first lens 1 has negative optical power. The object-side surface S2 of the first lens is concave, and the image-side surface S3 of the first lens is convex. The first lens 1 is located at the end of the optical path and serves as the last lens before the light rays exit. It uses its negative optical power to appropriately diverge and fine-tune the light rays to extend the exit pupil distance of the optical system or meet the incident angle matching requirements of the subsequent optical waveguide. Furthermore, the first lens 1 works in conjunction with the second lens 2 to ultimately complete the fine correction of residual spherical aberration and coma.

[0076] According to another embodiment of this application, an optical-mechanical lens module is provided, which differs from the aforementioned embodiment in the number of lenses in the lens group. In this embodiment, the first lens group in the lens group includes two lenses, namely a first lens 1 with negative optical power and a second lens 2 with negative optical power, arranged sequentially from the object side to the image side along the optical axis. The second lens group in the lens group includes two lenses, namely a fourth lens 4 with positive optical power and a fifth lens 5 with positive optical power, arranged sequentially from the object side to the image side along the optical axis.

[0077] Based on the above structure, light passes through the color-combining prism 7 set in the optical path and enters the four lenses of the lens group. The four lenses of the lens group, from the image side to the object side, are as follows: the fifth lens 5 with positive optical power, the fourth lens 4 with positive optical power, the second lens 2 with negative optical power, and the first lens 1 with negative optical power. The positive-positive-negative-negative optical power sequence of the four lenses, together with the field lens 6 with negative optical power, constitutes the core optical architecture for realizing light control and aberration correction.

[0078] The functions and characteristics of the field mirror 6 and the color combining prism 7 in this embodiment are the same as in the previous embodiment, and will not be repeated here.

[0079] Among them, the second lens 2, the fourth lens 4, and the fifth lens 5 are all plastic aspherical lenses, and the first lens 1 is a glass aspherical lens.

[0080] The fifth lens 5 has positive optical power. The object-side surface S10 of the fifth lens is concave, and the image-side surface S11 of the fifth lens is also concave. As the first lens in the lens group to receive light from the color combining prism 7, the fifth lens 5 is responsible for converging the light rays.

[0081] The fourth lens 4 has positive optical power. Its object-side surface S8 is convex, and its image-side surface S9 is concave. The function of the fourth lens 4 is similar to that of the fifth lens 5; these two lenses provide the main positive optical power for the entire optical system, and they converge the light rays from the color-combining prism 7. Simultaneously, they utilize the properties of their plastic material to compensate for temperature drift, correcting on-axis chromatic aberration, astigmatism, and field curvature in the optical system.

[0082] The second lens 2 has negative optical power. The object-side surface S4 of the second lens is convex, and the image-side surface S5 of the second lens is also convex. The second lens 2 provides the necessary negative optical power in the optical path to balance the aberrations introduced by the fourth lens 4 and the fifth lens 5, effectively correcting the distortion of the entire optical system and ensuring the accuracy of the geometric shape of the projected image.

[0083] The first lens 1 has negative optical power. The object-side surface S2 of the first lens is concave, and the image-side surface S3 of the first lens is also concave. As the last lens before the light rays exit, the first lens 1 uses its negative optical power to appropriately diverge and finely adjust the angle of the light rays to meet the requirements of the exit pupil distance or the incident angle of the subsequent optical waveguide. At the same time, the first lens 1 helps to smooth the deflection angle of the light rays, thereby finely correcting the residual spherical aberration and coma of the system.

[0084] It is understandable that the two implementation methods each have their own advantages in terms of technical effectiveness and application focus.

[0085] In the five-lens design, lens 1, lens 2, lens 3, lens 4, lens 5, and field lens 6 collectively contribute to the system's total optical power. This allows for a more even distribution of the total optical power across the five lenses, reducing the refractive stress on individual lenses and preventing excessively extreme surface curvature radii. This significantly reduces the difficulty of lens manufacturing and minimizes risks associated with edge thickness control and injection molding shrinkage. The multiple lenses also create a smoother transition of light between them, greatly improving the problem of severe edge light obstruction in large fields of view. Furthermore, lens 2, made of aspherical glass, works in conjunction with lens 1 and lens 3 to correct coma and spherical aberration in large fields of view.

[0086] In the four-lens design, the reduction in the number of lenses allows for further compression of the axial space, thereby reducing the axial dimensions of the optical-mechanical lens module and significantly lightening its weight. Furthermore, the reduction in the number of lenses also lowers the complexity of subsequent calibration processes, improving the product yield of the optical-mechanical lens module. Although the reduction in the number of lenses leads to a decrease in image quality, the four-lens design creates a unique negative-negative-positive-positive optical power arrangement. The negative spherical aberration and negative field curvature produced by the two consecutive negative optical power lenses in front can be precisely complementary to the positive spherical aberration and positive field curvature produced by the two consecutive positive optical power lenses behind, thus maintaining good image quality even with the reduction of one lens.

[0087] Furthermore, the optical engine lens module provided by the present application satisfies: -1.1 < F2 / F < -0.9, where F is the focal length of the optical engine lens module, and F2 is the focal length of the field lens 6. From the above conditional formula, it can be seen that the field lens 6 has a strong negative optical power. The field lens 6 can effectively compensate for the field curvature generated by the subsequent lens group, thus greatly smoothing the image field and ensuring a high resolution at the edge of the field of view at a large field angle. In addition, when the above conditional formula is satisfied, the field lens 6 can also reasonably control the angle of the chief ray emitted by the light-emitting chip and improve the relative illumination of the system. If F2 / F is lower than the lower limit of the above range (i.e., the negative optical power of the field lens 6 is too weak), the field curvature correction is insufficient and the edge image quality deteriorates; if F2 / F is higher than the upper limit of the above range (i.e., the negative optical power of the field lens 6 is too strong), it will cause excessive divergence of light rays, increase the convergence burden of the subsequent lens group, and is not conducive to the balance of aberrations.

[0088] Furthermore, the optical engine lens module also satisfies: 4 < TTL / ImgH < 5.1, 2.2 < TTL / D max < 2.4 and 3.5 < TTL / EPD < 3.8, where TTL is the total optical length of the optical engine lens module, ImgH is the maximum imaging height of the optical engine lens module, D max is the aperture of the largest lens in the optical engine lens module, and EPD is the entrance pupil diameter of the optical engine lens module.

[0089] The three key ratio relationships established in the present application: 4 < TTL / ImgH < 5.1, 2.2 < TTL / D max < 2.4 and 3.5 < TTL / EPD < 3.8 are the core design criteria for achieving a balance among a large field of view, a short total length, a small aperture, and high image quality.

[0090] 4 < TTL / ImgH < 5.1 defines the relationship between the total optical length TTL of the optical engine lens module and the maximum imaging height ImgH of the optical engine lens module, ensuring that the optical system has a short total length and a large imaging area. When the ratio of the total optical length TTL of the optical engine lens module to the maximum imaging height ImgH of the optical engine lens module satisfies the above conditional formula, the ultra-thinning and miniaturization of the optical system can be achieved, making it perfectly adapted to the light-emitting chip. If this ratio is lower than the lower limit of the above range, it means that the system is over-compressed, which will cause the curvature radius of each lens surface to be too small (the lens is too curved), not only greatly increasing the processing and forming difficulty, but also introducing high-order aberrations that are difficult to correct (such as severe distortion and field curvature), resulting in the deterioration of the edge image quality. If this ratio is higher than the upper limit of the above range, it means that the total length of the system is too long, and the requirements for lightweight and compact structures of wearable devices such as AR glasses cannot be met.

[0091] 2.2 < TTL / D max<2.4 defines the relationship between the total optical length TTL of the optical-mechanical lens module and the aperture D of the largest lens in the optical-mechanical lens module, ensuring the compression of the total length of the optical system and controlling the volume of the lens group. When the ratio of the total optical length TTL of the optical-mechanical lens module to the aperture D of the largest lens in the optical-mechanical lens module max meets the above conditional formula, it can effectively control the radial volume (outer diameter size) of the optical system, ensuring that the entire lens module can be smoothly assembled into the space-limited AR glasses legs or frames. If this ratio is lower than the lower limit of the above range, it means that the aperture of the largest lens is too large, which will cause a sharp increase in the radial volume of the lens, losing the miniaturization advantage. At the same time, it is difficult to control the edge thickness of the large-aperture lens, increasing the shrinkage risk during injection molding; if this ratio is higher than the upper limit of the above range, it means that the aperture of the largest lens is too small, which will cause serious occlusion of the marginal light rays under a large field of view, resulting in vignetting at the edge of the picture. max

[0092] 3.5 < TTL / EPD < 3.8 defines the relationship between the total optical length TTL of the optical-mechanical lens module and the entrance pupil diameter EPD of the optical-mechanical lens module, meeting the requirement of a larger aperture while shortening the total length of the lens group of the optical system. When the ratio of the total optical length TTL of the optical-mechanical lens module to the entrance pupil diameter EPD of the optical-mechanical lens module meets the above conditional formula, it can maintain a compact axial dimension on the premise of ensuring that the system has a large aperture (high light input). If this ratio is lower than the lower limit of the above range, it means that the aperture is forcibly enlarged under an extremely short total length, which will cause the light deflection angle to be too severe, generating serious spherical aberration and coma, greatly reducing the resolution at the center and edges; if this ratio is higher than the upper limit of the above range, it means that the entrance pupil diameter is too small, and the light-gathering ability of the system is insufficient, resulting in a dim AR projection image brightness and unable to meet the display requirements under complex ambient light.

[0093] By reasonably distributing the optical power of each lens and strictly controlling the above three conditional formulas, the optical-mechanical lens module achieves a perfect balance in three-dimensional space (axial length, radial width, and light-passing aperture), ensuring a large field of view, high brightness, and short total length.

[0094] Furthermore, the optical-mechanical lens module satisfies: 0.4 ≤ ImgH / F ≤ 0.5, where ImgH is the maximum imaging height of the optical-mechanical lens module and F is the focal length of the optical-mechanical lens module. By adjusting the ratio relationship between the maximum imaging height ImgH of the optical-mechanical lens module and the focal length F of the optical-mechanical lens module, it helps to expand the field of view angle of the optical system.

[0095] ​Furthermore, the optical-mechanical lens module satisfies: 0.8 < F1 / F < 0.9, where F1 is the focal length of the lens group and F is the focal length of the optical-mechanical lens module. This conditional expression ensures a proper distribution of optical power for the field lens group. When the focal length F1 of the lens group and the focal length F of the optical-mechanical lens module satisfy the above conditional expression, the imaging light rays can be effectively converged, which not only helps to correct spherical aberration but also effectively corrects chromatic aberration and other aberrations such as distortion. If the ratio is too small, the light-converging ability is insufficient and it is difficult to correct aberrations; if the ratio is too large, it will lead to too large lens curvature and increase the processing difficulty. This range maintains the rationality of the optical structure while ensuring the imaging quality.

[0096] Furthermore, the optical-mechanical lens module satisfies: 1.7 < #f < 1.9, where #f is the aperture value of the optical-mechanical lens module. This conditional expression limits the size of the aperture and ensures sufficient picture brightness even at a large viewing angle.

[0097] Furthermore, the optical-mechanical lens module satisfies: 1.9 < Td / F < 2.1, where Td is the distance along the optical axis from the object side surface S2 of the first lens to the image side surface S15 of the field lens, and F is the focal length of the optical-mechanical lens module. This conditional expression limits the axial lengths of the field lens group, the dichroic prism 7, and the lens group, making the system have a more compact structure and being conducive to shortening the total length of the optical system. If the ratio is too small (Td is too short), there is insufficient physical space between the lenses, which will cause the lenses to be unable to be processed or assembled; if the ratio is too large (Td is too long), it will violate the original intention of the AR glasses to pursue a short and small size. This range (1.9 - 2.1) is the most compact structure achievable under the premise of ensuring a reasonable light deflection angle.

[0098] Furthermore, the optical-mechanical lens module satisfies: 0.55 < BL / TTL ≤ 0.6, where BL is the distance along the optical axis from the image side surface S11 of the fifth lens to the imaging surface of the optical-mechanical lens module, and TTL is the total optical length of the optical-mechanical lens module. This conditional expression ensures a sufficient back working distance. When the total optical length TTL is extremely compressed (<10 mm), this conditional expression ensures that the proportion of the back focal length BL in the total length is maintained at 55% - 60%, ensuring that even in the design of an ultra-short TTL, there is still sufficient space for the light rays to smoothly transition from the lens group to the screen, avoiding optical occlusion or assembly difficulties caused by insufficient space.

[0099] Further, the optical-mechanical lens module satisfies: 1.3 < Y2 / Y1 < 1.7, where Y1 is the maximum effective radius of the object-side surface S2 of the first lens, and Y2 is the maximum effective radius of the image-side surface S15 of the field lens. This conditional expression limits the aperture ratio of the first lens 1 and the field lens 6, preventing the aperture of the field lens 6 from being too large, thereby helping to compress the overall volume of the field lens group and the lens group of the optical system. At the same time, by reasonably matching the front and rear apertures, the marginal rays under a large field of view can be effectively converged, avoiding vignetting caused by aperture mismatch and expanding the field angle.

[0100] In this application, there are at least two bonding gaps with different sizes between each field lens 6 and the incident surface of the dichroic prism 7. This is not a random processing error but a structure that inevitably forms to solve specific optical problems. Specifically, since the central wavelengths of the red, green, and blue channel beams are different, when combined with the specific focal length distribution of this application (-1.1 < F2 / F < -0.9), the sensitivity of each channel to aberration will show significant differences (for example, the blue light channel is extremely sensitive to position offset). This natural physical difference makes it impossible for the traditional unified gap assembly to simultaneously meet the clarity requirements of the three channels. Therefore, this application adopts an active calibration process to perform independent position compensation based on the actual imaging feedback of each channel. Since the compensation amounts required for each channel are different, different bonding gaps will inevitably form after curing. Through this differential gap structure, this application not only absorbs the sensitivity differences and processing tolerances of each channel but also effectively decouples the optical performance and mechanical processing accuracy, thereby ensuring the high-resolution imaging quality of the final optical-mechanical lens module.

[0101] Taking the assembly in the Z direction (i.e., along the optical axis of each field lens) as an example, under this specific power distribution, the spatial position of the field lens 6 is extremely sensitive to the system aberration. The test data shows that when the field lens 6 only shifts 30 μm in the Z direction, it will cause drastic changes in field curvature (about 5.5 μm), back focal length (about 38 μm), and chromatic aberration (about 5 pixels). Moreover, the MTF peak sensitivities of different color channels to the Z-direction shift show huge stepped differences: the peak of the blue light channel drops by about 24 points, the red light channel drops by about 10 points, and the green light channel only drops by about 1 point.

[0102] Faced with such differences in channel sensitivity, conventional equal-gap assembly would inevitably lead to severe degradation of the imaging quality of highly sensitive channels such as blue light. Therefore, in order to achieve perfect overlap of the three channel beams on the final image plane, eliminate chromatic aberration, and focus on compensating for the peak performance of the blue light channel, the final assembly positions of the three field lenses 6 in the Z-axis must be adjusted according to the actual situation. After these three different Z-axis positions are solidified by the adhesive layer, the physical structure directly manifests as different sizes of the adhesive gaps between the three field lenses 6 and the corresponding incident surfaces of the color combining prism 7. It is precisely by utilizing this differentiated gap structure that this application solves the problem of inconsistent channel sensitivity, ultimately achieving high-resolution, high-quality imaging.

[0103] The following are four specific embodiments of the optical-mechanical lens module.

[0104] Table 1 is a conditional parameter table for the optical-mechanical lens module of each embodiment.

[0105] Table 1

[0106]

Example 1

[0107] The first lens 1, the third lens 3, the fourth lens 4, the fifth lens 5, and the field lens 6 are all plastic aspherical lenses, while the second lens 2 is a glass aspherical lens.

[0108] Among them, the first lens 1 has negative optical power, the object-side surface S2 of the first lens is concave, and the image-side surface S3 of the first lens is concave; the second lens 2 has positive optical power, the object-side surface S4 of the second lens is convex, and the image-side surface S5 of the second lens is convex; the third lens 3 has negative optical power, the object-side surface S6 of the third lens is convex, and the image-side surface S7 of the third lens is concave; the fourth lens 4 has positive optical power, the object-side surface S8 of the fourth lens is convex, and the image-side surface S9 of the fourth lens is convex; the fifth lens 5 has positive optical power, the object-side surface S10 of the fifth lens is concave, and the image-side surface S11 of the fifth lens is convex; and the field lens 6 has negative optical power, the object-side surface S14 of the field lens is concave, and the image-side surface S15 of the field lens is concave.

[0109] In this embodiment, the focal length F of the optical engine lens module is 4.4mm, the aperture value #f is 1.76, the total optical length TTL of the optical engine lens module is 9.05mm, and the maximum field of view FOV of the optical engine lens module is 50°. Further, F2 / F = -1.07, TTL / ImgH = 4.11, and TTL / D... max =2.37, TTL / EPD=3.62, ImgH / F=0.5, F1 / F=0.89, Td / F=1.98, BL / TTL=0.60, Y2 / Y1=1.53.

[0110] Table 2 shows the basic parameters of the optical-mechanical lens module in Example 1, where the units for radius of curvature, thickness, and effective focal length are all millimeters (mm).

[0111] Table 2

[0112] In the table above, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S14, and S15 represent the object-side surface and image-side surface of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the field lens 6 mentioned above, respectively. Among them, S12, which was not mentioned above, is the object-side surface of the color combining prism, and S13 is the image-side surface of the color combining prism.

[0113] The surface shape of each lens can be defined using the following aspherical formula: ; Where X is a point on the aspherical surface at a distance Y from the optical axis, and its relative distance to the tangent plane at the intersection point on the optical axis of the aspherical surface; Y is the perpendicular distance between a point on the aspherical curve and the optical axis; R is the radius of curvature; k is the conic coefficient; and Ai is the i-th order aspherical coefficient.

[0114] Table 3 shows the aspherical coefficients of the optical-mechanical lens module in Example 1, illustrating the higher-order coefficients A4, A6, A8, and A... 10 A 12 A 14 and A 16 .

[0115] Table 3

[0116] Figure 3A The MTF characteristic curve of the green light path in the optomechanical lens module of Example 1 is shown. Figure 3B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 1 is shown. Figure 3CThe image shows the MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 1. From the MTF characteristic curves of the green light path, blue light path, and red light path, it can be seen that at a spatial frequency of 200 lp / mm, the MTF value of each field of view of the optical-mechanical lens module of Example 1 is greater than 0.5, proving that it can maintain excellent resolution and contrast over a wide temperature range.

[0117] Figure 4A , Figure 4B and Figure 4C The MTF defocus characteristic curves of the green light path in the optical-mechanical lens module of Example 1 at a frequency of 200 lp / mm at -10℃, 20℃, and 60℃ are shown in sequence. These MTF defocus characteristic curves further demonstrate that, within the operating temperature range, the center field-of-view optical transfer function (OTF) coefficient of the optical-mechanical lens module of Example 1 in the visible band remains stable above 0.6, verifying that the optical-mechanical lens module of Example 1 can still achieve stable imaging characteristics with high resolution and high contrast under harsh environmental conditions.

[0118] Figure 5A The astigmatism curve of the optical-mechanical lens module of Embodiment 1 is shown; Figure 5B The distortion curve of the optical-mechanical lens module of Embodiment 1 is shown; Figure 5C The relative illumination curve of the optical-mechanical lens module of Embodiment 1 is shown.

[0119] As can be seen from the astigmatism curves, both astigmatism curves (T and S) are relatively close to the 0mm focal position on the X-axis. The entire image plane (or the average position of the focal points of T and S) is closer to the ideal flat reference focal plane, and the field curvature is well controlled.

[0120] As can be seen from the distortion curve, the maximum distortion occurs at the edge of the field of view, and its absolute value is controlled within 10%, ensuring the geometric fidelity of the image.

[0121] As can be seen from the relative illumination curve, at the maximum field of view of 50°, the relative illumination of the edge field of view of the optical-mechanical lens module of Example 1 is still higher than 0.8. This indicates that the optical-mechanical lens module has excellent illumination uniformity, which can ensure that the brightness of the edge and center of the image is highly consistent and effectively avoid the vignetting phenomenon.

[0122] As can be seen from the figures, the optical-mechanical lens module in Example 1 achieves good imaging quality.

[0123]

Example 2

[0124] Figure 6 The diagram shows the optical lens structure of the green light path in the optical-mechanical lens module of Embodiment 2 (i.e., the optical lens structure corresponding to the first field lens 6a). The optical lens structure diagrams for the blue and red light paths can be found by referring to... Figure 2B and Figure 2C The only difference between Example 2 and Example 1 is that the parameters of each lens in the lens group are different, but the arrangement of the two is the same.

[0125] The first lens 1, the third lens 3, the fourth lens 4, the fifth lens 5, and the field lens 6 are all plastic aspherical lenses, while the second lens 2 is a glass aspherical lens.

[0126] Among them, the first lens 1 has negative optical power, the object-side surface S2 of the first lens is concave, and the image-side surface S3 of the first lens is concave; the second lens 2 has positive optical power, the object-side surface S4 of the second lens is convex, and the image-side surface S5 of the second lens is convex; the third lens 3 has negative optical power, the object-side surface S6 of the third lens is convex, and the image-side surface S7 of the third lens is concave; the fourth lens 4 has positive optical power, the object-side surface S8 of the fourth lens is convex, and the image-side surface S9 of the fourth lens is convex; the fifth lens 5 has positive optical power, the object-side surface S10 of the fifth lens is concave, and the image-side surface S11 of the fifth lens is convex; and the field lens 6 has negative optical power, the object-side surface S14 of the field lens is concave, and the image-side surface S15 of the field lens is concave.

[0127] In this embodiment, the focal length F of the optical engine lens module is 4.55mm, the aperture value #f is 1.82, the total optical length TTL of the optical engine lens module is 9mm, and the maximum field of view FOV of the optical engine lens module is 50°. Further, F2 / F = -0.95, TTL / ImgH = 4.60, and TTL / D... max =2.28, TTL / EPD=3.60, ImgH / F=0.43, F1 / F=0.90, Td / F=1.91, BL / TTL=0.60, Y2 / Y1=1.58.

[0128] Table 4 shows the basic parameters of the optical-mechanical lens module in Example 2, where the units for radius of curvature, thickness, and effective focal length are all millimeters (mm).

[0129] Table 4

[0130] In the table above, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S14, and S15 represent the object-side surface and image-side surface of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the field lens 6 mentioned above, respectively. Among them, S12, which was not mentioned above, is the object-side surface of the color combining prism, and S13 is the image-side surface of the color combining prism.

[0131] The surface shape of each lens can be defined using the following aspherical formula: ; Where X is a point on the aspherical surface at a distance Y from the optical axis, and its relative distance to the tangent plane at the intersection point on the optical axis of the aspherical surface; Y is the perpendicular distance between a point on the aspherical curve and the optical axis; R is the radius of curvature; k is the conic coefficient; and Ai is the i-th order aspherical coefficient.

[0132] Table 5 shows the aspherical coefficients of the optical-mechanical lens module in Example 2, illustrating the higher-order coefficients A4, A6, A8, and A6 for each surface. 10 A 12 A 14 and A 16 .

[0133] Table 5

[0134] Figure 7A The MTF characteristic curve of the green light path in the optomechanical lens module of Example 2 is shown. Figure 7B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 2 is shown. Figure 7C The image shows the MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 2. From the MTF characteristic curves of the green light path, blue light path, and red light path, it can be seen that at a spatial frequency of 200 lp / mm, the MTF value of each field of view of the optical-mechanical lens module of Example 2 is greater than 0.5, proving that it can maintain excellent resolution and contrast over a wide temperature range.

[0135] Figure 8A , Figure 8B and Figure 8CThe MTF defocus characteristic curves of the green light path in the optical-mechanical lens module of Example 2 at a frequency of 200 lp / mm at -10℃, 20℃, and 60℃ are shown in sequence. These MTF defocus characteristic curves further demonstrate that, within the operating temperature range, the center field-of-view optical transfer function (OTF) coefficient of the optical-mechanical lens module of Example 2 in the visible band remains stable above 0.6, verifying that the optical-mechanical lens module of Example 2 can still achieve stable imaging characteristics with high resolution and high contrast under harsh environmental conditions.

[0136] Figure 9A The astigmatism curve of the optical-mechanical lens module of Embodiment 2 is shown; Figure 9B The distortion curve of the optical-mechanical lens module in Embodiment 2 is shown; Figure 9C The relative illumination curve of the optical-mechanical lens module of Embodiment 2 is shown.

[0137] As can be seen from the astigmatism curves, both astigmatism curves (T and S) are relatively close to the 0mm focal position on the X-axis. The entire image plane (or the average position of the focal points of T and S) is closer to the ideal flat reference focal plane, and the field curvature is well controlled.

[0138] As can be seen from the distortion curve, the maximum distortion occurs at the edge of the field of view, and its absolute value is controlled within 10%, ensuring the geometric fidelity of the image.

[0139] As can be seen from the relative illuminance curve, at the maximum field of view of 50°, the relative illuminance of the edge field of view of the optical-mechanical lens module in Example 2 is still higher than 0.8. This indicates that the optical-mechanical lens module has excellent illuminance uniformity, which can ensure that the brightness of the edge and center of the image is highly consistent and effectively avoid the vignetting phenomenon.

[0140] As can be seen from the figures, the optical-mechanical lens module in Embodiment 2 achieves good imaging quality.

[0141]

Example 3

[0142] Figure 10 The diagram shows the optical lens structure of the green light path in the optical-mechanical lens module of Embodiment 3 (i.e., the optical lens structure corresponding to the first field lens 6a). The optical lens structure diagrams for the blue and red light paths can be found by referring to... Figure 2B and Figure 2CThe only difference between Example 3 and Example 1 is the parameters of each lens in the lens group and the number of lenses; the arrangement of the lenses is the same in both examples.

[0143] The second lens 2, the fourth lens 4, the fifth lens 5, and the field lens 6 are all plastic aspherical lenses, while the first lens 1 is a glass aspherical lens.

[0144] Among them, the first lens 1 has negative optical power, the object-side surface S2 of the first lens is concave, and the image-side surface S3 of the first lens is convex; the second lens 2 has negative optical power, the object-side surface S4 of the second lens is convex, and the image-side surface S5 of the second lens is concave; the fourth lens 4 has positive optical power, the object-side surface S8 of the fourth lens is convex, and the image-side surface S9 of the fourth lens is convex; the fifth lens 5 has positive optical power, the object-side surface S10 of the fifth lens is concave, and the image-side surface S11 of the fifth lens is convex; the field lens 6 has negative optical power, the object-side surface S14 of the field lens is concave, and the image-side surface S15 of the field lens is concave.

[0145] In this embodiment, the focal length F of the optical engine lens module is 4.61mm, the aperture value #f is 1.85, the total optical length TTL is 9.34mm, and the maximum field of view (FOV) is 50°. Further, F2 / F = -0.91, TTL / ImgH = 5.07, and TTL / D... max =2.32, TTL / EPD=3.74, ImgH / F=0.4, F1 / F=0.87, Td / F=1.93, BL / TTL=0.60, Y2 / Y1=1.61.

[0146] Table 6 shows the basic parameters of the optical-mechanical lens module in Example 3, where the units for radius of curvature, thickness, and effective focal length are all millimeters (mm).

[0147] Table 6

[0148] In the table above, S2, S3, S4, S5, S8, S9, S10, S11, S14, and S15 represent the object-side and image-side surfaces of the first lens 1, the second lens 2, the fourth lens 4, the fifth lens 5, and the field lens 6 mentioned above, respectively. Among them, S12, which was not mentioned above, is the object-side surface of the color combining prism, and S13 is the image-side surface of the color combining prism.

[0149] The surface shape of each lens can be defined using the following aspherical formula: ; Where X is a point on the aspherical surface at a distance Y from the optical axis, and its relative distance to the tangent plane at the intersection point on the optical axis of the aspherical surface; Y is the perpendicular distance between a point on the aspherical curve and the optical axis; R is the radius of curvature; k is the conic coefficient; and Ai is the i-th order aspherical coefficient.

[0150] Table 7 shows the aspherical coefficients of the optical-mechanical lens module in Example 3, illustrating the higher-order coefficients A4, A6, A8, and A... 10 A 12 A 14 and A 16 .

[0151] Table 7

[0152] Figure 11A The MTF characteristic curve of the green light path in the optomechanical lens module of Example 3 is shown. Figure 11B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 3 is shown. Figure 11C The image shows the MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 3. From the MTF characteristic curves of the green light path, blue light path, and red light path, it can be seen that at a spatial frequency of 200 lp / mm, the MTF value of each field of view of the optical-mechanical lens module of Example 3 is greater than 0.5, proving that it can maintain excellent resolution and contrast over a wide temperature range.

[0153] Figure 12A , Figure 12B and Figure 12C The MTF defocus characteristic curves of the green light path in the optical-mechanical lens module of Example 3 at a frequency of 200 lp / mm at -10℃, 20℃, and 60℃ are shown in sequence. These MTF defocus characteristic curves further demonstrate that, within the operating temperature range, the center field-of-view optical transfer function (OTF) coefficient of the optical-mechanical lens module of Example 3 in the visible band remains stable above 0.6, verifying that the optical-mechanical lens module of Example 3 can still achieve stable imaging characteristics with high resolution and high contrast under harsh environmental conditions.

[0154] Figure 13A The astigmatism curve of the optical-mechanical lens module of Embodiment 3 is shown; Figure 13B The distortion curve of the optical-mechanical lens module in Embodiment 3 is shown; Figure 13C The relative illumination curve of the optical-mechanical lens module of Embodiment 3 is shown.

[0155] As can be seen from the astigmatism curves, both astigmatism curves (T and S) are relatively close to the 0mm focal position on the X-axis. The entire image plane (or the average position of the focal points of T and S) is closer to the ideal flat reference focal plane, and the field curvature is well controlled.

[0156] As can be seen from the distortion curve, the maximum distortion occurs at the edge of the field of view, and its absolute value is controlled within 10%, ensuring the geometric fidelity of the image.

[0157] As can be seen from the relative illumination curve, at the maximum field of view of 50°, the relative illumination of the edge field of view of the optical-mechanical lens module of Example 1 is still higher than 0.8. This indicates that the optical-mechanical lens module has excellent illumination uniformity, which can ensure that the brightness of the edge and center of the image is highly consistent and effectively avoid the vignetting phenomenon.

[0158] As can be seen from the figures, the optical-mechanical lens module in Example 3 achieves good imaging quality.

[0159]

Example 4

[0160] Figure 14 The diagram shows the optical lens structure of the green light path in the optical-mechanical lens module of Embodiment 4 (i.e., the optical lens structure corresponding to the first field lens 6a). The optical lens structure diagrams for the blue and red light paths can be found by referring to... Figure 2B and Figure 2C The only difference between Example 4 and Example 1 is the parameters of each lens in the lens group and the number of lenses; the arrangement of the lenses is the same in both examples.

[0161] The second lens 2, the fourth lens 4, the fifth lens 5, and the field lens 6 are all plastic aspherical lenses, while the first lens 1 is a glass aspherical lens.

[0162] Among them, the first lens 1 has negative optical power, the object-side surface S2 of the first lens is concave, and the image-side surface S3 of the first lens is convex; the second lens 2 has negative optical power, the object-side surface S4 of the second lens is convex, and the image-side surface S5 of the second lens is concave; the fourth lens 4 has positive optical power, the object-side surface S8 of the fourth lens is convex, and the image-side surface S9 of the fourth lens is convex; the fifth lens 5 has positive optical power, the object-side surface S10 of the fifth lens is concave, and the image-side surface S11 of the fifth lens is convex; the field lens 6 has negative optical power, the object-side surface S14 of the field lens is concave, and the image-side surface S15 of the field lens is concave.

[0163] In this embodiment, the focal length F of the optical engine lens module is 4.3mm, the aperture value #f is 1.72, the total optical length TTL of the optical engine lens module is 9.3mm, and the maximum field of view FOV of the optical engine lens module is 50°. Further, F2 / F = -0.98, TTL / ImgH = 5.03, and TTL / D... max =2.35, TTL / EPD=3.72, ImgH / F=0.43, F1 / F=0.84, Td / F=2.07, BL / TTL=0.57, Y2 / Y1=1.34.

[0164] Table 8 shows the basic parameters of the optical-mechanical lens module in Example 4, where the units for radius of curvature, thickness, and effective focal length are all millimeters (mm).

[0165] Table 8

[0166] In the table above, S2, S3, S4, S5, S8, S9, S10, S11, S14, and S15 represent the object-side and image-side surfaces of the first lens 1, the second lens 2, the fourth lens 4, the fifth lens 5, and the field lens 6 mentioned above, respectively. Among them, S12, which was not mentioned above, is the object-side surface of the color combining prism, and S13 is the image-side surface of the color combining prism.

[0167] The surface shape of each lens can be defined using the following aspherical formula: ; Where X is a point on the aspherical surface at a distance Y from the optical axis, and its relative distance to the tangent plane at the intersection point on the optical axis of the aspherical surface; Y is the perpendicular distance between a point on the aspherical curve and the optical axis; R is the radius of curvature; k is the conic coefficient; and Ai is the i-th order aspherical coefficient.

[0168] Table 9 shows the aspherical coefficients of the optical-mechanical lens module in Example 4, illustrating the higher-order coefficients A4, A6, A8, and A... 10 A 12 A 14 and A 16 .

[0169] Table 9

[0170] Figure 15A The MTF characteristic curve of the green light path in the optomechanical lens module of Example 4 is shown. Figure 15B The MTF characteristic curve of the blue light path in the optical-mechanical lens module of Example 4 is shown. Figure 15CThe image shows the MTF characteristic curve of the red light path in the optical-mechanical lens module of Example 4. From the MTF characteristic curves of the green light path, blue light path, and red light path, it can be seen that at a spatial frequency of 200 lp / mm, the MTF value of each field of view of the optical-mechanical lens module of Example 4 is greater than 0.5, proving that it can maintain excellent resolution and contrast over a wide temperature range.

[0171] Figure 16A , Figure 16B and Figure 16C The MTF defocus characteristic curves of the green light path in the optical-mechanical lens module of Example 4 at a frequency of 200 lp / mm at -10℃, 20℃, and 60℃ are shown in sequence. These MTF defocus characteristic curves further demonstrate that, within the operating temperature range, the center field-of-view optical transfer function (OTF) coefficient of the optical-mechanical lens module of Example 4 in the visible band remains stable above 0.6, verifying that the optical-mechanical lens module of Example 4 can still achieve stable imaging characteristics with high resolution and high contrast under harsh environmental conditions.

[0172] Figure 17A The astigmatism curve of the optical-mechanical lens module of Embodiment 4 is shown; Figure 17B The distortion curve of the optical-mechanical lens module in Embodiment 4 is shown; Figure 17C The relative illumination curve of the optical-mechanical lens module of Embodiment 4 is shown.

[0173] As can be seen from the astigmatism curves, both astigmatism curves (T and S) are relatively close to the 0mm focal position on the X-axis. The entire image plane (or the average position of the focal points of T and S) is closer to the ideal flat reference focal plane, and the field curvature is well controlled.

[0174] As can be seen from the distortion curve, the maximum distortion occurs at the edge of the field of view, and its absolute value is controlled within 10%, ensuring the geometric fidelity of the image.

[0175] As can be seen from the relative illumination curve, at the maximum field of view of 50°, the relative illumination of the edge field of view of the optical-mechanical lens module of Example 1 is still higher than 0.8. This indicates that the optical-mechanical lens module has excellent illumination uniformity, which can ensure that the brightness of the edge and center of the image is highly consistent and effectively avoid the vignetting phenomenon.

[0176] As can be seen from the figures, the optical-mechanical lens module in Example 4 achieves good imaging quality.

[0177] This application embodiment also provides a method for assembling an optical-mechanical lens module. The optical-mechanical lens module includes a lens group, a color combining prism 7, and a field lens group. The field lens group includes three field lenses 6, which correspond to green, blue, and red primary color light sources, respectively. The method includes: S1 Initial positioning: Pre-position the three field lenses 6 on the three incident surfaces of the color combining prism 7 respectively; S2 Active Calibration: Based on the actual imaging results of the optical-mechanical lens module, the relative positions and / or attitudes of the three field lenses 6 and their corresponding incident surfaces are adjusted respectively so that the imaging quality of each optical path meets the preset requirements; after adjustment, adhesive gaps are formed between the three field lenses 6 and their corresponding incident surfaces, and at least two adhesive gaps are different in size. S3 Curing: The three field lenses 6, after active calibration, are bonded and fixed to the color combining prism 7.

[0178] Furthermore, step S1 initial positioning includes S11 laser leveling and S12 camera centering: S11 Laser Leveling: Using a laser alignment device, the tilt and axial spacing of the field lens 6 relative to the corresponding incident surface are adjusted to eliminate the tilt deviation of the field lens 6 relative to the corresponding incident surface and to establish a preset bonding gap. S12 Camera Centering: Using the camera positioning device, the translation position of the field lens relative to the corresponding incident surface is adjusted in a plane perpendicular to the corresponding optical axis, so that the central optical axis of the field lens is aligned with the center position of the corresponding incident surface. By using laser leveling in step S11 and camera centering in step S12, the three field lenses 6 are pre-positioned and aligned with the three incident surfaces of the color combining prism 7.

[0179] It is understood that, specifically, the terms "Z-direction" and "axial direction" mentioned in this invention do not refer to a globally unified absolute spatial coordinate system, but rather to a local reference coordinate system independently established for each field lens 6. Specifically, for any field lens 6, its corresponding Z-direction is defined as the direction of its own optical axis (i.e., approximately perpendicular to the incident surface of its corresponding color-combining prism). Since the three field lenses 6 are respectively positioned on three different incident surfaces of the color-combining prism 7, their respective optical axes are non-parallel in absolute space (e.g., mutually orthogonal). Therefore, the Z-direction corresponding to each field lens 6 points in different directions in absolute space. Correspondingly, the X-direction, Y-direction, plane perpendicular to the optical axis, and XY translation mentioned in this invention all refer to locally orthogonal planes constructed based on the independent Z-direction of each field lens 6. During active calibration, the axial and lateral adjustments performed on each field lens 6 are all performed independently within their respective local reference coordinate systems.

[0180] Furthermore, step S2, active calibration, includes: S21 Reference Calibration: Select one of the three field lenses 6 as the reference field lens, and prioritize adjusting the spatial position and / or attitude of the reference field lens relative to the corresponding incident surface; S22 Reference Calibration: Using the calibration result of the reference field lens as a reference, adjust the spatial position and / or attitude of the remaining two non-reference field lenses relative to the corresponding incident surfaces.

[0181] In the active calibration process of this invention, the selection of the reference field lens is not random, but scientifically selected based on the optical characteristic parameters (such as position sensitivity and upper limit of performance specifications) of each channel field lens. Specifically, this invention provides the following two optional methods for selecting the reference field lens.

[0182] Method 1: Select the field lens with the lowest sensitivity from the three field lenses as the reference field lens. According to optical design data, the sensitivity of the blue, red, and green field lenses typically follows a distribution pattern of: blue field lens > red field lens > green field lens. Therefore, in this embodiment, the green field lens is preferred as the reference field lens for priority active calibration. The lower the sensitivity, the smaller the impact of changes in the spatial position of the field lens on image quality (such as MTF peak), and the higher its tolerance to assembly tolerances. Using the green field lens with the lowest sensitivity as the first fixed reference establishes an extremely stable physical and optical reference anchor point for the entire optomechanical system. This effectively avoids the significant cumulative errors in subsequent non-reference field lens calibration caused by the slight glue curing shrinkage or stress drift of the reference lens itself when using a high-sensitivity field lens as the reference, thereby improving the stability and first-pass yield of multi-channel alignment.

[0183] Method Two: Selecting a reference field lens based on the principle of performance bottleneck. If, during the engineering phase, it is found that the Z-axis gap adjustment of the blue light field lens has a significant impact on the MTF peak value, and due to the limitations of optical materials, the initial performance specifications of the blue light channel are often at the lowest level among the three channels, easily becoming a bottleneck restricting the overall performance of the optomechanical system. Therefore, when assessing the risk of a performance bottleneck in the blue light channel, this embodiment can select the blue field lens as the reference field lens for active calibration; subsequently, using the calibration parameters of the blue field lens as a reference, the green and red field lenses are adjusted separately to balance the overall performance and compensate for system chromatic aberration. This method ensures the lowest performance limit of the system by prioritizing the adjustment of the blue light field lens, which is the most difficult to adjust and has the most stringent lower limit of specifications, to its optimal state (peak value locked); subsequently, the green and red light channels, which have a larger performance margin and lower sensitivity, are used to actively accommodate and match the blue light channel. This strategy can achieve a perfect balance of performance among the three channels and extreme suppression of chromatic aberration without increasing the cost of optical components, greatly improving the final yield of optomechanical modules with performance margins.

[0184] For ease of description, this application uses a green light field lens as the reference field lens as an example to describe the active alignment process of each field lens 6.

[0185] In this application, the three field lenses 6 include a first field lens 6a corresponding to a green light source, a second field lens 6b corresponding to a blue light source, and a third field lens 6c corresponding to a red light source. As an example, the first field lens 6a can be selected as the reference field lens, and the second field lens 6b and the third field lens 6c can be selected as non-reference field lenses.

[0186] Furthermore, the active calibration steps for the first field mirror 6a include: Axial adjustment: Based on the MTF defocus characteristic curve of the green light path, the axial position of the first field lens 6a is adjusted along the optical axis to optimize the back focus and field curvature of the first field lens 6a. Lateral adjustment: Based on the MTF defocus characteristic curve of the green light path, according to the symmetry of the image or the symmetry of the MTF defocus characteristic curve, adjust the translation position of the first field lens 6a in a plane perpendicular to the optical axis to correct the eccentricity and tilt error of the first field lens 6a. Reference Recording: Record the spatial position coordinates and attitude angles of the first field lens 6a after adjustment. The spatial position coordinates include X, Y and Z coordinates, and the attitude angles include tilt angles U and V. Furthermore, when the first field lens 6a is at the recorded spatial position coordinates and attitude angles, acquire the vertical axis chromatic aberration feature point parameters at at least one preset field of view point. Use the adjustment parameters and vertical axis chromatic aberration feature point parameters of the first field lens 6a as reference references for calibrating the second field lens 6b and the third field lens 6c.

[0187] Furthermore, the aforementioned axial adjustment step further includes: adjusting the axial position of the first field lens 6a along the optical axis based on the MTF defocus characteristic curve of the green light path, so that the peak value of the MTF defocus characteristic curve of the central field of view is aligned with the designed back focus position, and minimizing the axial deviation between the peak value of the MTF defocus characteristic curve of each edge field of view and the peak value of the MTF defocus characteristic curve of the central field of view.

[0188] Furthermore, the aforementioned lateral adjustment steps further include: based on the MTF defocus characteristic curve of the green light path, adjusting the translation position of the first field lens 6a in a plane perpendicular to the optical axis according to the symmetry of the image, so that the sharpness difference of the target image acquired by the camera in the meridional or sagittal direction tends to be minimized; or, based on the MTF defocus characteristic curve of the green light path, adjusting the translation position of the first field lens 6a in a plane perpendicular to the optical axis according to the symmetry of the MTF defocus characteristic curve, so that the morphological difference of the MTF defocus characteristic curve of the entire field of view in the meridional or sagittal direction tends to be minimized.

[0189] Furthermore, the above-mentioned benchmark recording step further includes: moving the first field lens 6a to the recorded spatial position coordinates and attitude angle, acquiring the image height value and the peak value of the MTF defocus characteristic curve at at least one preset field of view point, and using the image height value and the peak value of the MTF defocus characteristic curve of the first field lens 6a as a reference benchmark for calibrating the second field lens 6b and the third field lens 6c.

[0190] Furthermore, the active calibration steps for the second field mirror 6b include: Lateral alignment: Based on the MTF defocus characteristic curve of the blue light path, adjust the translation position of the second field lens 6b in a plane perpendicular to the optical axis so that the line connecting the peaks of the MTF defocus characteristic curve of the entire field of view of the blue light path and the line connecting the peaks of the MTF defocus characteristic curve of the entire field of view of the green light path tend to coincide. Axial alignment: Based on the MTF defocus characteristic curve of the blue light path, the axial position of the second field lens 6b is adjusted along the optical axis so that the peak value of the MTF defocus characteristic curve of the blue light path tends to coincide with the peak value of the MTF defocus characteristic curve of the green light path. Furthermore, when the second field lens 6b is in this axial position, the image height difference between the blue light path and the green light path at at least one preset field of view is recorded as the transverse chromatic aberration feature point parameter. If the image height difference does not meet the preset difference, another new second field lens 6b is replaced and recalibrated. The two second field lenses 6b before and after replacement both correspond to the blue light path, that is, the two second field lenses 6b before and after replacement both correspond to the same primary color light source. Reference Record: Record the spatial position coordinates and attitude angles after the adjustment of the second field mirror 6b. The spatial position coordinates include the X, Y and Z coordinates, and the attitude angles include the tilt angle U and the tilt angle V.

[0191] Furthermore, the active calibration steps for the third field mirror 6c include: Lateral alignment: Based on the MTF defocus characteristic curve of the red light path, adjust the translation position of the third field lens 6c in a plane perpendicular to the optical axis so that the line connecting the peaks of the MTF defocus characteristic curve of the entire field of view of the red light path and the line connecting the peaks of the MTF defocus characteristic curve of the entire field of view of the green light path tend to coincide. Axial alignment: Based on the MTF defocus characteristic curve of the red light path, the axial position of the third field lens 6c is adjusted along the optical axis so that the peak value of the MTF defocus characteristic curve of the red light path tends to coincide with the peak value of the MTF defocus characteristic curve of the green light path. Furthermore, when the third field lens 6c is in this axial position, the image height difference between the red light path and the green light path at at least one preset field of view is recorded as the transverse chromatic aberration characteristic point parameter. If the image height difference does not meet the preset difference, another new third field lens 6c is replaced and recalibrated. The two third field lenses 6c before and after replacement both correspond to the red light path, that is, the two third field lenses 6c before and after replacement both correspond to the same primary color light source. Reference Record: Record the spatial position coordinates and attitude angles after the adjustment of the third field mirror 6c. The spatial position coordinates include the X, Y and Z coordinates, and the attitude angles include the tilt angle U and the tilt angle V.

[0192] Furthermore, the curing step includes: Return to position away: Move the three field lenses 6 away from the corresponding incident surfaces respectively, so that a dispensing operation space is formed between the field lens 6 and the color combining prism 7. Flip the color combining prism 7 so that at least one incident surface of the color combining prism 7 is in a position that facilitates dispensing, and apply adhesive to the corresponding bonding areas of the three incident surfaces in sequence. Positioning fine-tuning: Move the three field lenses 6 to the spatial position coordinates and attitude angle determined by the active calibration, and judge whether the imaging quality of the corresponding optical path meets the preset requirements based on the MTF defocus characteristic curve of the corresponding optical path. If the imaging quality does not meet the preset requirements, return to the active calibration step to fine-tune the relative position and / or attitude of the field lens 6 and the corresponding incident surface. Exposure and curing: Move the three field lenses 6 to the spatial position coordinates and attitude angle determined by active calibration, expose and cure the adhesive. After exposure and curing, release the clamping mechanism used to hold the three field lenses 6, and judge whether the imaging quality of the optical-mechanical lens module meets the preset requirements based on the MTF defocus characteristic curve of the optical lens module.

[0193] For compact optical systems with high-power elements, their theoretical performance can deteriorate rapidly due to the accumulation of assembly tolerances (such as eccentricity and tilt). This application provides an active calibration assembly method based on actual imaging feedback, breaking through the tolerance barriers of traditional rigid assembly and ensuring that the theoretical design performance of the optical-mechanical lens module can be translated into excellent optical quality with high fidelity in actual mass production.

[0194] The assembly method provided in this application effectively compensates for the asymmetry of the MTF defocus characteristic curve caused by the accumulated eccentricity tolerance of the preceding lens assembly by actively compensating for the XY translation of the three field lenses 6 in the field lens group. Therefore, the optical-mechanical lens module of this application not only has high-resolution potential in its design, but also ensures the balance and consistency of the actual imaging of the center and edge fields of view under complex tolerance superposition conditions in its manufacturing process, which is difficult to achieve with traditional passive assembly processes.

[0195] As shown in the astigmatism diagram, the meridional (T) and sagittal (S) astigmatism curves in the theoretical design closely follow the 0mm focal length, exhibiting excellent flat field characteristics. In actual product assembly, to accurately capture this narrow optimal flat field position, the process described in this application dynamically monitors and adjusts the Z-axis position of the field lens 6 in the field lens group, independently compensating for manufacturing deviations in the back focal length of each channel. This process ensures that the actual photosensitive surface (or display surface) can precisely coincide with the ideal flat reference focal plane illustrated, thereby translating the field curvature control advantage at the design stage into clear image quality at the product stage.

[0196] Furthermore, although theoretical designs (such as distortion maps) optimize the geometric fidelity of monochromatic light, in the actual manufacturing of multicolor optical engine systems, minute assembly differences between color channels can cause severe chromatic aberration. This application employs a multi-wavelength sequential process (e.g., using the green field lens as a reference, actively adjusting the Z-axis position of the blue / red field lenses to compensate for axial chromatic aberration, and combining transverse chromatic aberration feature point parameters for lateral / attitude reference compensation), dynamically eliminating residual asymmetric magnification chromatic aberration (LCA) at the physical level. This process feature enables the product of this application to achieve low distortion while eliminating rainbow edge phenomena at the edge of the field of view, achieving sub-pixel-level color alignment.

[0197] In this application, the gaps are at least two different, which is the physical manifestation of each channel field lens after independent active calibration based on actual imaging feedback. Since the optimal focal planes of the red, green, and blue optical paths objectively differ due to axial chromatic aberration, this invention allows each field lens 6 to have an independent optimal position in its Z-axis (optical axis) direction, thereby compensating for the axial chromatic aberration of the system and ensuring that the light from each channel achieves confocal convergence on the final image plane.

[0198] Furthermore, the differentiated gaps actually constitute a buffer layer for tolerance absorption. It can effectively compensate for the surface shape error, angular tolerance of the color-combining prism 7, and the thickness / curvature tolerance of the field lens 6 itself. This means that, without increasing the processing precision of individual optical elements (i.e., without increasing component costs), it is still possible to assemble an optomechanical module with extremely high MTF performance through differentiated gap compensation, which greatly reduces the manufacturing cost of high-end optomechanical systems and improves mass production yield.

[0199] Furthermore, different gaps correspond to different thicknesses of cured adhesive layers. When facing complex environments such as high and low temperature cycles, the differentiated adhesive layer thickness can better release and absorb the thermal stress caused by the different thermal expansion coefficients of each component, avoid deformation or delamination of optical components due to rigid extrusion, and significantly improve the long-term optical stability of the optomechanical module.

[0200] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. An optical-mechanical lens module, characterized in that, From the object side to the image side, it includes: lens group, color combining prism and field lens group; The lens group includes a first lens group and a second lens group arranged sequentially from the object side to the image side. The first lens group has negative optical power and includes at least two lenses with negative optical power. The second lens group has positive optical power and includes two lenses with positive optical power. The field lens assembly includes three negative power field lenses. The three field lenses are respectively fixed to the three incident surfaces of the color combining prism by adhesive layers. Each of the three field lenses and its corresponding incident surface has an adhesive gap, and at least two of the adhesive gaps are different in size. The adhesive gaps are formed by an active calibration process, which is an adjustment of the relative position between the field lenses and the color combining prism based on the actual imaging results of the optical engine lens module. Wherein, the focal length of the optical-mechanical lens module is F, and the focal length of each field lens in the field lens group is F2, and the two satisfy: -1.1 <F2 / F<-0.9。 2. The optical-mechanical lens module as described in claim 1, characterized in that, The total optical length of the optical-mechanical lens module is TTL, and the maximum imaging height of the optical-mechanical lens module is ImgH, both of which satisfy: 4 <TTL / ImgH<5.1。 3. The optical-mechanical lens module as described in claim 1, characterized in that, The total optical length of the optical-mechanical lens module is TTL, and the aperture of the largest lens in the optical-mechanical lens module is D. max Both satisfy: 2.2 <TTL / D max <2.

4.

4. The optical-mechanical lens module as described in claim 1, characterized in that, The total optical length of the optical engine lens module is TTL, and the entrance pupil diameter of the optical engine lens module is EPD, both satisfying: 3.5 <TTL / EPD<3.8。 5. The optical-mechanical lens module as described in claim 1, characterized in that, The focal length of the optical-mechanical lens module is F, and the maximum imaging height of the optical-mechanical lens module is ImgH. Both satisfy the condition: 0.4≤ImgH / F≤0.

5.

6. The optical-mechanical lens module as described in claim 1, characterized in that, The focal length of the optical engine lens module is F, and the focal length of the lens group is F1, both satisfying: 0.8 <F1 / F<0.9。 7. The optical-mechanical lens module as described in claim 1, characterized in that, The aperture value of the optical engine lens module is #f, and the two satisfy: 1.7 < #f < 1.

9.

8. The optical-mechanical lens module as described in claim 1, characterized in that, The first lens group includes three lenses, which are arranged sequentially from the object side to the image side along the optical axis: a first lens, a second lens, and a third lens. The first lens has negative optical power, the second lens has positive optical power, and the third lens has negative optical power. The second lens group includes two lenses, which are arranged sequentially from the object side to the image side along the optical axis: a fourth lens and a fifth lens. The fourth lens has positive optical power, and the fifth lens has positive optical power.

9. The optical-mechanical lens module as described in claim 1, characterized in that, The first lens group includes two lenses, which are arranged sequentially from the object side to the image side along the optical axis: a first lens and a second lens, wherein the first lens has negative optical power and the second lens has negative optical power; the second lens group includes two lenses, which are arranged sequentially from the object side to the image side along the optical axis: a fourth lens and a fifth lens, wherein the fourth lens has positive optical power and the fifth lens has positive optical power.

10. The optical-mechanical lens module as described in claim 8 or 9, characterized in that, The focal length of the optical-mechanical lens module is F, and the distance along the optical axis from the object-side surface of the first lens to the image-side surface of the field lens is Td. Both satisfy: 1.9 <Td / F<2.1。 11. The optical-mechanical lens module as described in claim 8 or 9, characterized in that, The total optical length of the optical-mechanical lens module is TTL, and the distance along the optical axis from the image-side surface of the fifth lens to the imaging plane of the optical-mechanical lens module is BL. Both satisfy: 0.55 <BL / TTL≤0.6。 12. The optical-mechanical lens module as described in claim 8 or 9, characterized in that, The maximum effective radius of the object-side surface of the first lens is Y1, and the maximum effective radius of the image-side surface of the field lens is Y2, satisfying: 1.3 <Y2 / Y1<1.7。 13. The optical-mechanical lens module as described in claim 8, characterized in that, The first lens, the third lens, the fourth lens, the fifth lens, and each of the field lenses are all plastic aspherical lenses, and the second lens is a glass aspherical lens.

14. The optical-mechanical lens module as described in claim 13, characterized in that, The object-side surface of the first lens is concave, and the image-side surface of the first lens is concave. The object-side surface of the second lens is convex, and the image-side surface of the second lens is convex. The object-side surface of the third lens is convex, and the image-side surface of the third lens is concave. The object-side surface of the fourth lens is convex, and the image-side surface of the fourth lens is convex. The object-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex. The object-side surface of the field lens is concave, and the image-side surface of the field lens is also concave.

15. The optical-mechanical lens module as described in claim 9, characterized in that, The second lens, the fourth lens, the fifth lens, and each of the field lenses are all plastic aspherical lenses, while the first lens is a glass aspherical lens.

16. The optical-mechanical lens module as described in claim 15, characterized in that, The object-side surface of the first lens is concave, and the image-side surface of the first lens is convex. The object-side surface of the second lens is convex, and the image-side surface of the second lens is concave. The object-side surface of the fourth lens is convex, and the image-side surface of the fourth lens is convex. The object-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex. The object-side surface of the field lens is concave, and the image-side surface of the field lens is also concave.

17. A method for assembling an optical-mechanical lens module, characterized in that, The optical-mechanical lens module includes a lens group, a color combining prism, and a field lens group. The field lens group includes three field lenses, each corresponding to a primary color light source of green, blue, and red. The method includes the following steps: S1 Initial Positioning: Pre-position and initially align the three field lenses with the three incident surfaces of the color combining prism; S2 Active Calibration: Based on the actual imaging results of the optical-mechanical lens module, the relative positions and / or attitudes between the three field lenses and their corresponding incident surfaces are adjusted respectively so that the imaging quality of each optical path meets the preset requirements; after adjustment, an adhesive gap is formed between the three field lenses and their corresponding incident surfaces, and at least two of the adhesive gaps are different in size. S3 Curing: The three field lenses, after active calibration, are bonded and fixed to the color combining prism.

18. The assembly method as described in claim 17, characterized in that, The initial positioning step S1 includes: S11 Laser Leveling: Using a laser alignment device, the tilt amount and axial spacing of the field lens relative to the corresponding incident surface are adjusted to eliminate the tilt deviation of the field lens relative to the corresponding incident surface and establish a preset bonding gap. S12 Camera Centering: Using a camera positioning device, the translational position of the field lens relative to the corresponding incident surface is adjusted in a plane perpendicular to the corresponding optical axis, so that the central optical axis of the field lens is aligned with the center position of the corresponding incident surface. Specifically, through steps S11 and S12, the field lens is pre-positioned and initially aligned with the corresponding incident surface side of the color combining prism.

19. The assembly method as described in claim 17, characterized in that, The active calibration step S2 includes: S21 Reference Calibration: Select one of the three field lenses as the reference field lens, and preferentially adjust the spatial position and / or attitude of the reference field lens relative to the corresponding incident surface; S22 Reference Calibration: Using the calibration result of the reference field lens as a reference, adjust the spatial position and / or attitude of the remaining two non-reference field lenses relative to the corresponding incident surfaces.

20. The assembly method as described in claim 19, characterized in that, The reference calibration step S21 includes: Axial adjustment: Based on the MTF defocus characteristic curve of the monochromatic light source path corresponding to the reference field lens, the axial position of the reference field lens is adjusted along the optical axis to optimize the back focus and field curvature of the reference field lens. Lateral adjustment: Based on the MTF defocus characteristic curve of the monochromatic light source path corresponding to the reference field lens, and according to the symmetry of the image or the symmetry of the MTF defocus characteristic curve, the translation position of the reference field lens is adjusted in a plane perpendicular to the optical axis to correct the eccentricity and tilt error of the reference field lens. Reference recording: Record the spatial position coordinates and attitude angles of the reference field lens after adjustment, wherein the spatial position coordinates include X coordinates, Y coordinates and Z coordinates, and the attitude angles include tilt angle U and tilt angle V; and, when the reference field lens is at the recorded spatial position coordinates and attitude angles, collect the transverse chromatic aberration feature point parameters at at least one preset field of view point, and use the adjustment parameters of the reference field lens and the transverse chromatic aberration feature point parameters as a reference reference for calibrating the non-reference field lens.

21. The assembly method as described in claim 20, characterized in that, The axial adjustment step further includes: adjusting the axial position of the reference field lens along the optical axis based on the MTF defocus characteristic curve of the monochromatic light source path corresponding to the reference field lens, so that the peak value of the MTF defocus characteristic curve of the central field of view is aligned with the designed back focus position, and minimizing the axial deviation between the peak value of the MTF defocus characteristic curve of each edge field of view and the peak value of the MTF defocus characteristic curve of the central field of view.

22. The assembly method as described in claim 20, characterized in that, The lateral adjustment step further includes: based on the MTF defocus characteristic curve of the monochromatic light source path corresponding to the reference field lens, and according to the symmetry of the image, adjusting the translation position of the reference field lens in a plane perpendicular to the optical axis, so that the sharpness difference of the target image acquired by the camera in the meridional or sagittal direction is minimized; or, Based on the MTF defocus characteristic curve of the monochromatic light source path corresponding to the reference field lens, and according to the symmetry of the MTF defocus characteristic curve, the translation position of the reference field lens is adjusted in a plane perpendicular to the optical axis so that the morphological difference of the MTF defocus characteristic curve in the meridional or sagittal direction of the entire field of view is minimized.

23. The assembly method as described in claim 20, characterized in that, The reference recording step further includes: moving the reference field lens to the recorded spatial position coordinates and attitude angle, collecting the image height value and the peak value of the MTF defocus characteristic curve at at least one preset field of view point, and using the image height value and the peak value of the MTF defocus characteristic curve of the reference field lens as a reference reference for calibrating the non-reference field lens.

24. The assembly method as described in claim 19, characterized in that, The reference calibration step S22 includes: Lateral alignment: Based on the MTF defocus characteristic curve of the monochromatic light source optical path corresponding to the non-reference field lens, adjust the translation position of the non-reference field lens in a plane perpendicular to the optical axis so that the line connecting the peak values ​​of the MTF defocus characteristic curve of the monochromatic light source optical path corresponding to the non-reference field lens across the entire field of view tends to coincide with the line connecting the peak values ​​of the MTF defocus characteristic curve of the monochromatic light source optical path corresponding to the reference field lens across the entire field of view. Axial alignment: Based on the MTF defocus characteristic curve of the monochromatic light source path corresponding to the non-reference field lens, the axial position of the non-reference field lens is adjusted along the optical axis so that the peak value of the MTF defocus characteristic curve of the monochromatic light source path corresponding to the non-reference field lens tends to coincide with the peak value of the MTF defocus characteristic curve of the monochromatic light source path corresponding to the reference field lens; and when the non-reference field lens is in this axial position, the image height difference between the monochromatic light source path corresponding to the non-reference field lens and the monochromatic light source path corresponding to the reference field lens at at least one preset field of view is recorded as the transverse chromatic aberration feature point parameter. If the image height difference does not meet the preset difference, another new non-reference field lens is replaced and recalibrated; wherein, the two non-reference field lenses before and after replacement correspond to the same primary color light source; Reference Record: Record the spatial position coordinates and attitude angles of the non-reference field lens after adjustment. The spatial position coordinates include X coordinates, Y coordinates and Z coordinates, and the attitude angles include tilt angle U and tilt angle V.

Images