Projection optical system and projection module for its application
Patent Information
- Application Number
- CN202522078858.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-26
- Publication Date
- 2026-09-15
- Estimated Expiration
- 2035-09-26
AI Technical Summary
传统系统多采用较多镜片实现像质校正，导致结构冗杂、体积庞大
本实用新型提供一种投影光学系统及其应用的投影模组，由6枚透镜构成，通过合理配置各个透镜的屈折力和面型，有效矫正了场曲、畸变及倍率色差，获得了边缘明亮、解析度均匀的高质量画面，本实用新型配置的投影光学系统，具有整体尺寸小、低成本及大光圈的特点，结构紧凑，便于加工和安装，同时，大光圈的配置可增加光学系统的进光量及更高的成像质量。
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Figure CN224758800U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical imaging, and more particularly to a projection optical system and a projection module for its application. Background Technology
[0002] In recent years, projection and augmented reality (AR) systems have placed higher demands on the miniaturization, high definition, and low chromatic aberration of optical modules. Traditional systems often use a large number of lenses for image quality correction, resulting in complex structures and large sizes. At the same time, achieving image-square-field output in a limited space remains a technical challenge, and existing designs often struggle to balance brightness, contrast, and overall optical length, limiting their application in lightweight AR devices and micro-projectors.
[0003] Therefore, there is an urgent need for an optical system architecture that is compact, has good aberration control, and possesses high optical performance. Utility Model Content
[0004] This application provides a projection optical system that, by rationally configuring the refractive power and surface shape of each lens, effectively corrects field curvature, distortion, and magnification chromatic aberration, thereby obtaining a high-quality image with bright edges and uniform resolution.
[0005] A projection optical system, characterized in that: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens are arranged sequentially along the optical axis from the imaging side to the image source side; The first lens has negative optical power and its imaging side is concave. The second lens has optical power; The third lens has positive optical power and its image source side is convex. The fourth lens has optical power, and its imaging side is convex. The fifth lens has positive optical power and its image source side is convex. The sixth lens has negative optical power, its imaging side is concave, and its image source side is convex.
[0006] Preferably, the optical system satisfies the following conditions: 1.4 mm<(FNO*f*ImgH) / TTL<1.7 mm; Where FNO is the F-number of the optical system, f is the effective focal length of the optical system, ImgH is half the diagonal length of the effective pixel area on the image source surface of the optical system, and TTL is the on-axis distance from the imaging side surface of the first lens of the optical system to the image source surface of the optical system.
[0007] Preferably, the optical system satisfies the following relationship: 3.0 / mm < TTL / (EPD*T01) < 4.0 / mm; Where TTL is the on-axis distance from the imaging side surface of the first lens of the optical system to the image source surface of the optical system, EPD is the entrance pupil diameter of the optical system, and T01 is the on-axis distance from the imaging surface of the optical system to the imaging side surface of the first lens.
[0008] Preferably, the optical system satisfies the following relationship: 0.29 < DT62 / |R12| < 1; Where R12 is the radius of curvature of the side surface of the sixth lens image source, and DT62 is the maximum effective radius of the side surface of the sixth lens image source.
[0009] Preferably, the optical system satisfies the following relationship: 14.0 < f*tan(HFOV) / |SAG1| < 20.0; where f is the effective focal length of the optical system, HFOV is half of the maximum field of view of the optical system, and SAG1 is the distance from the maximum effective aperture of the imaging side of the first lens to the intersection of the imaging side of the first lens and the optical axis in the direction parallel to the optical axis.
[0010] Preferably, the optical system satisfies the following relationship: 1.0 < (CT1 + CT6) / |SAG1 + SAG12| < 2.0; where CT1 is the thickness of the first lens on the optical axis, CT6 is the thickness of the sixth lens on the optical axis, SAG1 is the distance from the maximum effective aperture of the imaging side of the first lens to the intersection of the imaging side of the first lens and the optical axis in the direction parallel to the optical axis, and SAG12 is the distance from the maximum effective aperture of the image source side of the sixth lens to the intersection of the image source side of the sixth lens and the optical axis in the direction parallel to the optical axis.
[0011] Preferably, the optical system satisfies the following relationship: 3.3 < ΣCT / CT3 < 6.0; where ΣCT is the sum of the center thicknesses of the first lens, second lens, third lens, fourth lens, fifth lens and sixth lens on the optical axis in the optical system, and CT3 is the center thickness of the third lens on the optical axis.
[0012] Preferably, the optical system satisfies the following relationship: 15.5 < BFL / ( T12 + T23) < 18.5; Wherein, BFL is the shortest distance along the optical axis from the image source side of the sixth lens to the image source surface of the optical system, T12 is the air gap between the first lens and the second lens on the optical axis, and T23 is the air gap between the second lens and the third lens on the optical axis.
[0013] Preferably, the optical system satisfies the following relationship: 1.0 < |(f3-f1) / f3| < 3.0; where f1 is the effective focal length of the first lens and f3 is the effective focal length of the third lens.
[0014] Preferably, the optical system satisfies the following relationship: 1.6 < f / f345 < 1.9; where f is the effective focal length of the optical system, and f345 is the effective combined focal length of the third, fourth, and fifth lenses.
[0015] Preferably, the optical system satisfies the following relationship: 2.2 < |(f23+f456) / f| < 5.0; Where f is the effective focal length of the optical system, f23 is the combined focal length of the second and third lenses, and f456 is the combined focal length of the fourth, fifth, and sixth lenses.
[0016] Preferably, the F-number of the optical system is ≤1.89, and the total optical length TTL satisfies: TTL ≤12 mm.
[0017] Another object of this application is to provide a projection module, including at least an optical lens, wherein the above-described projection optical system is installed within the optical lens.
[0018] Compared with the prior art, the beneficial effects of this application are as follows: This invention provides a projection optical system and its application projection module, which consists of 6 lenses. By rationally configuring the refractive power and surface shape of each lens, field curvature, distortion, and magnification chromatic aberration are effectively corrected, resulting in a high-quality image with bright edges and uniform resolution. The projection optical system configured in this invention features small overall size, low cost, and a large aperture. It has a compact structure, is easy to process and install, and the large aperture configuration can increase the amount of light entering the optical system and achieve higher imaging quality. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.
[0020] Figure 1 This is a schematic diagram of the structure of the optical system or projection module in Embodiment 1 of this application; Figure 2 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical system or projection module in Embodiment 1 of this application; Figure 3 This is a schematic diagram of the structure of the optical system or projection module in Embodiment 2 of this application; Figure 4 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical system or projection module in Embodiment 2 of this application; Figure 5 This is a schematic diagram of the structure of the optical system or projection module in Embodiment 3 of this application; Figure 6These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical system or projection module in Embodiment 3 of this application; Figure 7 This is a schematic diagram of the structure of the optical system or projection module in Embodiment 4 of this application; Figure 8 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical system or projection module in Embodiment 4 of this application. Detailed Implementation
[0021] This application provides a projection optical system comprising a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6 arranged sequentially along the optical axis from the imaging side to the image source side. The first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, and sixth lens E6 are aspherical lenses and are separated by air gaps. The first lens E1 has negative optical power and its imaging side is concave. The second lens E2 has optical power. The third lens E3 has positive optical power and its image source side is convex. The fourth lens E4 has optical power and its imaging side is convex. The fifth lens E5 has positive optical power and its image source side is convex. The sixth lens E6 has negative optical power, its imaging side is concave, and its image source side is convex. The imaging optical system has an F-number ≤ 1.89 and an overall length ≤ 12 mm.
[0022] The optical system of this application consists of 6 lenses. By rationally configuring the refractive power and surface shape of each lens, field curvature, distortion, and magnification chromatic aberration are effectively corrected, resulting in a high-quality image with bright edges and uniform resolution. The projection optical system configured in this utility model has the characteristics of small overall size, low cost, and large aperture. It has a compact structure, is easy to process and install, and the large aperture configuration can increase the amount of light entering the optical system and achieve higher imaging quality.
[0023] Further, the optical system satisfies the following relationship: 1.4 mm < (FNO*f*ImgH) / TTL < 1.7 mm; wherein, FNO is the F-number of the optical projection lens, f is the effective focal length of the optical system, ImgH is half the diagonal length of the effective pixel area on the image source surface of the optical lens, and TTL is the on-axis distance from the imaging side surface of the first lens of the optical lens to the image source surface. By defining the ratio among the aperture, the effective focal length, half the diagonal length of the effective pixel area on the image source surface and the on-axis distance from the imaging side surface of the first lens to the image source surface of the optical projection system, it can ensure that aberration is within the correctable range and reduce design complexity. When the value is lower than the lower limit of the relationship, on the basis of ensuring a large aperture of the optical system, the total optical length of the optical system is further increased, which is not conducive to the miniaturization of the optical system; when the value is higher than the upper limit of the relationship, it is not conducive to satisfying the field-of-view range of the optical lens, sufficient image space information cannot be transmitted, which affects the projection quality of the optical lens.
[0024] Further, the optical system satisfies the following relationship: 3.0 / mm < TTL / (EPD*T01) < 4.0 / mm; wherein, TTL is the on-axis distance from the imaging side surface of the first lens of the optical lens to the image source surface, EPD is the entrance pupil diameter of the optical system, and T01 is the on-axis distance from the imaging surface of the optical system to the imaging side surface of the first lens. By defining the ratio range between the on-axis distance from the imaging side surface of the first lens of the optical lens to the image source surface, the entrance pupil diameter of the optical system and the on-axis distance from the imaging surface of the optical system to the imaging side surface of the first lens, it can ensure that while the system has high brightness and sufficient distance for accommodating structural components, the total optical length is minimized, thereby achieving the unification of high performance and small volume. When the value is lower than the lower limit of the relationship, the distance from the imaging surface of the optical system to the imaging side surface of the first lens is too small, which is not conducive to the layout of structural components such as the lens barrel, thereby affecting the engineering practicability of the entire optical lens; when the value is higher than the upper limit of the relationship, the system structure is lengthy, and it is difficult to achieve the unification of high performance and miniaturization.
[0025] Further, the optical system satisfies the following relationship: 0.29<DT62 / |R12|<1; wherein R12 is the curvature radius of the image-source side surface of the sixth lens, and DT62 is the maximum effective radius of the image-source side surface of the sixth lens. By defining the ratio of the maximum effective half-aperture of the image-source side surface of the sixth lens to the curvature radius of the image-source side surface of the sixth lens, it is beneficial to reasonably control the bending degree of the image-source side surface of the sixth lens, and increase the aperture of the sixth lens in the direction perpendicular to the optical axis, thereby improving the relative illuminance of projection; meanwhile, it is also beneficial to suppress the aberration of the edge field of view and improve the projection quality of the system. When the value is lower than the lower limit of the relational expression, the effective aperture of the image-source side surface of the sixth lens is too small, which causes serious deflection of edge rays and increases edge aberration, which is not conducive to improving projection quality. When the value is higher than the upper limit of the relational expression, the surface shape of the image side surface of the sixth lens is too curved, the deflection degree of light rays is too large, which also easily leads to increased edge aberration and is not conducive to improving projection quality.
[0026] Further, the optical system satisfies the following relationship: 14.0<f*tan(HFOV) / |SAG1|<20.0; wherein f is the effective focal length of the optical system, HFOV is half of the maximum field of view angle of the optical system, and SAG1 is the distance parallel to the optical axis direction from the position of the maximum effective clear aperture of the imaging side surface of the first lens to the intersection point of the imaging side surface of the first lens and the optical axis. By controlling the ratio range of the above relational expression, the ratio of the product of the focal length of the optical system and half of the maximum field of view angle of the optical system to the distance parallel to the optical axis direction from the position of the maximum effective clear aperture of the imaging side surface of the first lens to the intersection point of the imaging side surface of the first lens and the optical axis is controlled, which can effectively control the field of view size of the optical system, so that light rays can reasonably pass through the optical system and reach the imaging surface, thereby improving the projection quality of the system. When the value is lower than the lower limit of the relational expression, the maximum field of view angle of the optical system is too small, and the imaging surface cannot obtain sufficient image space information; when the value is higher than the upper limit of the relational expression, the distance parallel to the optical axis direction from the position of the maximum effective clear aperture of the imaging side surface of the first lens to the intersection point of the imaging side surface of the first lens and the optical axis is too small, and the imaging side surface of the first lens is too flat, which leads to excessive deflection angle when edge light rays enter, increases edge aberration, and affects the projection quality of the system Further, the optical system satisfies the following relationship: 3.3 < ΣCT / CT3 < 6.0; wherein ΣCT is a sum of central thicknesses on an optical axis of a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens of the optical system, and CT3 is a central thickness of the third lens on the optical axis. By limiting the range of the above conditional expression, the ratio of the sum of the central thicknesses on the optical axis of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens of the optical system to the central thickness of the third lens can be reasonably configured, which facilitates reasonable deflection of light when passing through the third lens, thereby improving the projection quality of the system, and meanwhile facilitates controlling the central thickness of the third lens on the optical axis, making the third lens easy to process and produce. When the value is lower than the lower limit of the relationship, the sum of the central thicknesses on the optical axis of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens of the optical system is too small, and the change of thickness-to-thickness ratio at various positions of the lenses in the optical system is too large, which is not conducive to reasonable deflection of light, reduces the MTF value of the system, and leads to a decrease in system resolution; when the value is higher than the upper limit of the relationship, the central thickness of the third lens on the optical axis is too small, which reduces the processability of the third lens and is not conducive to the practicability of the optical system.
[0027] Further, the optical system satisfies the following relationship: 1.0 < |(f3-f1) / f3| < 3.0; wherein f1 is an effective focal length of the first lens, and f3 is an effective focal length of the third lens. By reasonably controlling the focal length ratio of the first lens to the third lens, the optical system can meet a large field-of-view range while obtaining higher projection resolution. When the value exceeds the upper limit of the relationship, the refractive power of the first lens and the third lens is insufficient, so that light from an image source surface is difficult to refract to an imaging surface, which is not conducive to expanding the field-of-view range of the optical system; when the value is lower than the lower limit of the relationship, the refractive power of the first lens and the third lens is too strong, which easily causes strong astigmatism and chromatic aberration, and is not conducive to high-resolution projection characteristics.
[0028] Further, the optical system satisfies the following relationship: 1.6 < f / f345 < 1.9; wherein f is an effective focal length of the optical projection system, and f345 is an effective combined focal length of the third lens, the fourth lens and the fifth lens. By constraining the ratio of the combined focal length of the third lens, the fourth lens and the fifth lens to the effective focal length of the optical lens, the optical power distribution of the third lens, the fourth lens and the fifth lens can be properly configured, allowing the fourth lens to provide various coordination performances, so that based on satisfying the miniaturization design of the optical lens, the balance of internal aberration of the optical lens can also be achieved, which further helps adjust the field curvature and astigmatism at the projection edge of the optical lens, and satisfies the projection quality of the optical lens for the surrounding environment.
[0029] Furthermore, the optical system satisfies the following relationship: 2.2 < |(f23+f456) / f| < 5.0; where f23 is the combined focal length of the second and third lenses, f456 is the combined focal length of the fourth, fifth, and sixth lenses, and f is the effective focal length of the optical projection system. By ensuring that the optical system satisfies the above relationship, it is beneficial to reasonably constrain the ratio of the combined focal length of the second, third, fourth, fifth, and sixth lenses to the focal length of the optical system, correct the aberrations produced by the lenses after the sixth lens, improve the resolving power of the optical system, and at the same time, reduce the exit angle of the light after it is refracted by the optical system, so that the light emitted from the image source surface can enter the optical system at a smaller angle, thereby improving the optical performance of the imaging surface and enhancing the projection quality of the projection module.
[0030] Furthermore, the optical system satisfies the following relationship: 1.0 < (CT1 + CT6) / |SAG1 + SAG12| < 2.0; where CT1 is the thickness of the first lens on the optical axis, CT6 is the thickness of the sixth lens on the optical axis, SAG1 is the distance from the maximum effective aperture of the imaging side of the first lens to the intersection of the imaging side of the first lens and the optical axis in a direction parallel to the optical axis, and SAG12 is the distance from the maximum effective aperture of the image source side of the sixth lens to the intersection of the image source side of the sixth lens and the optical axis in a direction parallel to the optical axis. By using the ratio range of the above expression, the shapes of the first and sixth lenses can be constrained to correct the field curvature of the projection optical lens, reduce the risk of ghosting, and thus improve the projection quality of the optical lens. When the ratio is below the upper limit, the sagitta of the imaging side of the first lens and the image source side of the sixth lens is too large, causing them to be overly curved. This is detrimental to the manufacturing and assembly of the first and sixth lenses, and can easily lead to a decrease in the projection quality of the optical lens. When the ratio is above the upper limit, the thickness of the first and sixth lenses along the optical axis is too large, which is detrimental to the miniaturization design of the optical system. Further, the optical system satisfies the following relationship: 15.5 < BFL / (T12 + T23) < 18.5; wherein BFL is the shortest distance from the image side surface of the sixth lens to the image plane of the optical system in the optical axis direction, T12 is the air gap between the first lens and the second lens on the optical axis, and T23 is the air gap between the second lens and the third lens on the optical axis. When the above conditional expression is satisfied, by controlling the shortest distance from the image side surface of the sixth lens to the image plane of the optical system in the optical axis direction within a reasonable range, the matching degree between the image source, the prism and the optical system is effectively ensured, and the matching property between the optical system and the image source screen is guaranteed; meanwhile, controlling the thickness of the above combined lenses on the optical axis can effectively improve the compactness of the combined lens structure, reduce the total optical length of the optical system, further reduce the size of the optical system, better promote the development toward miniaturization, is also conducive to the molding and assembly of the combined lenses, reduces the manufacturing cost of the optical system, additionally reduces the decentration sensitivity of the optical system, and is conducive to ensuring the projection effect of the optical system. Example 1 Reference is made below to Figures 1 to 2 describes the optical projection lens according to embodiment 1 of the present application. Figure 1 shows a schematic structural diagram of the optical projection lens according to embodiment 1 of the present application.
[0031] As shown in Figure 1 , the optical projection lens according to the exemplary embodiment of the present application sequentially includes along the optical axis from the imaging side to the image source side: an imaging surface STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6 and an image source surface S15.
[0032] The first lens E1 has negative refractive power, its imaging side surface S1 is a concave surface, and its image source side surface S2 is a concave surface. The second lens E2 has positive refractive power, its imaging side surface S3 is a convex surface, and its image source side surface S4 is a concave surface. The third lens E3 has positive refractive power, its imaging side surface S5 is a convex surface, and its image source side surface S6 is a convex surface. The fourth lens E4 has positive refractive power, its imaging side surface S7 is a convex surface, and its image source side surface S8 is a concave surface. The fifth lens E5 has positive refractive power, its imaging side surface S9 is a convex surface, and its image source side surface S10 is a convex surface. The sixth lens E6 has negative refractive power, its imaging side surface S11 is a concave surface, and its image source side surface S12 is a convex surface. Image side surface S14. Light from the image source surface S15 sequentially passes through each surface from S14 to S1 and finally forms an image on the imaging surface STO.
[0033] Table 1 shows the surface type, curvature radius, thickness and material of each lens of the optical projection lens in Example 1, wherein the units of curvature radius and thickness are both millimeters (mm).
[0034] Table 1
[0035] In Table 1, the imaging side and image source side of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:
[0036] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the conic coefficient, Am is the aspherical coefficient, and r max The maximum value of the radial radius coordinate is u = r / r max Table 4 provides the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 for each aspherical surface that can be used in the first embodiment.
[0037] Table 2
[0038] Example 2 The following is for reference Figures 3 to 4 Describes an optical projection lens according to Embodiment 2 of this application. Figure 3 A schematic diagram of the structure of an optical projection lens according to Embodiment 2 of this application is shown.
[0039] like Figure 3 As shown, the optical projection lens according to an exemplary embodiment of this application includes, in sequence along the optical axis from the imaging side to the image source side: imaging surface STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6 and image source surface S15.
[0040] The first lens E1 has negative optical power, with its imaging side S1 being concave and its image source side S2 being convex. The second lens E2 has negative optical power, with its imaging side S3 being concave and its image source side S4 being concave. The third lens E3 has positive optical power, with its imaging side S5 being concave and its image source side S6 being convex. The fourth lens E4 has positive optical power, with its imaging side S7 being convex and its image source side S8 being convex. The fifth lens E5 has positive optical power, with its imaging side S9 being concave and its image source side S10 being convex. The sixth lens E6 has negative optical power, with its imaging side S11 being concave and its image source side S12 being convex. The image source side S14 is also present. Light from the image source side S15 passes sequentially through each surface S14 to S1 and is finally imaged onto the imaging surface STO.
[0041] Table 3 shows the surface type, radius of curvature, thickness, and material of each lens in the optical projection lens of Example 2, wherein the units for radius of curvature and thickness are millimeters (mm).
[0042] Table 3
[0043] In Table 3, the imaging side and image source side of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:
[0044] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the conic coefficient, Am is the aspherical coefficient, and r max The maximum value of the radial radius coordinate is u = r / r max Table 4 provides the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 for each aspherical surface that can be used in the second embodiment.
[0045] Table 4
[0046] Example 3 The following is for reference Figures 5 to 6 Describes an optical projection lens according to Embodiment 3 of this application. Figure 5 A schematic diagram of the structure of an optical projection lens according to Embodiment 3 of this application is shown.
[0047] like Figure 5 As shown, the optical projection lens according to an exemplary embodiment of this application includes, in sequence along the optical axis from the imaging side to the image source side: imaging surface STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6 and image source surface S15.
[0048] The first lens E1 has negative optical power, with its imaging side S1 being concave and its image source side S2 being concave. The second lens E2 has positive optical power, with its imaging side S3 being concave and its image source side S4 being convex. The third lens E3 has positive optical power, with its imaging side S5 being concave and its image source side S6 being convex. The fourth lens E4 has negative optical power, with its imaging side S7 being convex and its image source side S8 being concave. The fifth lens E5 has positive optical power, with its imaging side S9 being convex and its image source side S10 being convex. The sixth lens E6 has negative optical power, with its imaging side S11 being concave and its image source side S12 being convex. The image source side S14. Light from the image source surface 15 passes sequentially through each surface S14 to S1 and is finally imaged onto the imaging surface STO.
[0049] Table 5 shows the surface type, radius of curvature, thickness, and material of each lens of the optical projection lens in Example 3, wherein the units for radius of curvature and thickness are millimeters (mm).
[0050] Table 5
[0051] In Table 5, the imaging side and image source side of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:
[0052] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the conic coefficient, Am is the aspherical coefficient, and r max The maximum value of the radial radius coordinate is u = r / r max Table 6 provides the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 for each aspherical surface that can be used in the third embodiment.
[0053] Table 6
[0054] Example 4 The following is for reference Figures 7 to 8 Describes an optical projection lens according to Embodiment 4 of this application. Figure 7 A schematic diagram of the structure of an optical projection lens according to Embodiment 4 of this application is shown.
[0055] like Figure 7As shown, the optical projection lens according to an exemplary embodiment of this application includes, in sequence along the optical axis from the imaging side to the image source side: imaging surface STO, first lens E1, second lens E2, third lens E3, fourth lens E4, fifth lens E5, sixth lens E6 and image source surface S15.
[0056] The first lens E1 has negative optical power, with its imaging side S1 being concave and its image source side S2 being concave. The second lens E2 has positive optical power, with its imaging side S3 being concave and its image source side S4 being convex. The third lens E3 has positive optical power, with its imaging side S5 being concave and its image source side S6 being convex. The fourth lens E4 has negative optical power, with its imaging side S7 being convex and its image source side S8 being concave. The fifth lens E5 has positive optical power, with its imaging side S9 being concave and its image source side S10 being convex. The sixth lens E6 has negative optical power, with its imaging side S11 being concave and its image source side S12 being convex. The image source side S14. Light from the image source surface 15 passes sequentially through each surface S14 to S1 and is finally imaged onto the imaging surface STO.
[0057] Table 7 shows the surface type, radius of curvature, thickness, and material of each lens in the optical projection lens of Example 4, wherein the units for radius of curvature and thickness are millimeters (mm).
[0058] Table 7
[0059] In Table 7, the imaging side and image source side of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:
[0060] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, K is the conic coefficient, Am is the aspherical coefficient, and r max The maximum value of the radial radius coordinate is u = r / r max Table 8 provides the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 for each aspherical surface that can be used in the fourth embodiment.
[0061] Table 8
[0062] In Examples 1-4, the basic data is as follows: Table 9
[0063] In Examples 1-4, each conditional expression satisfies the conditions in the table below: Table 10
[0064] A projection module includes at least an optical lens, within which a projection optical system as described above is installed. This projection optical system, by selecting one glass aspherical lens and five plastic aspherical lenses, and rationally configuring the refractive power and surface shape of each lens, effectively corrects field curvature, distortion, and chromatic aberration, resulting in a high-quality image with bright edges and uniform resolution. Furthermore, this system employs a front aperture design and strictly controls the air gap between the imaging surface and the first lens to be greater than 1mm. This effectively converges the incident angle of light rays at the edge of the maximum field of view, significantly reducing off-axis aberrations, thereby improving the clarity and uniformity of the entire image plane and preventing blurring or distortion at the image edges. Simultaneously, this gap provides valuable layout space for the mechanical structure of the lens barrel and light-shielding components, effectively suppressing stray light interference, improving system contrast, and relaxing the assembly tolerances between the lens edges and the lens barrel, reducing manufacturing difficulty and costs, and enhancing the engineering practicality and reliability of the design.
[0065] The above description provides one or more embodiments in conjunction with specific content, and does not imply that the specific implementation of this utility model is limited to these descriptions. Any methods or structures that are similar to or identical to those of this utility model, or any technical deductions or substitutions made based on the concept of this utility model, should be considered within the protection scope of this utility model.
Claims
1. A projection optical system, characterized in that: A first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens are arranged sequentially along the optical axis from the imaging side to the image source side; The first lens has negative optical power and its imaging side is concave. The second lens has optical power; The third lens has positive optical power and its image source side is convex. The fourth lens has optical power, and its imaging side is convex. The fifth lens has positive optical power and its image source side is convex. The sixth lens has negative optical power, its imaging side is concave, and its image source side is convex.
2. The projection optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: The optical system satisfies the following conditions: 1.4 mm <(FNO*f*ImgH) / TTL< 1.7 mm; Where FNO is the F-number of the optical system, f is the effective focal length of the optical system, ImgH is half the diagonal length of the effective pixel area on the image source surface of the optical system, and TTL is the on-axis distance from the imaging side surface of the first lens of the optical system to the image source surface of the optical system.
3. The projection optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 3.0 / mm < TTL / (EPD*T01) < 4.0 / mm; Where TTL is the on-axis distance from the imaging side surface of the first lens of the optical system to the image source surface of the optical system, EPD is the entrance pupil diameter of the optical system, and T01 is the on-axis distance from the imaging surface of the optical system to the imaging side surface of the first lens.
4. The projection optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 0.29 < DT62 / |R12| < 1; Where R12 is the radius of curvature of the side surface of the sixth lens image source, and DT62 is the maximum effective radius of the side surface of the sixth lens image source.
5. The projection optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 14.0 < f*tan(HFOV) / |SAG1| < 20.0; and / or 1.0 <(CT1+CT6) / |SAG1 +SAG12| < 2.0; Where f is the effective focal length of the optical system, HFOV is half of the maximum field of view of the optical system, CT1 is the thickness of the first lens on the optical axis, CT6 is the thickness of the sixth lens on the optical axis, SAG1 is the distance from the maximum effective aperture of the imaging side of the first lens to the intersection of the imaging side of the first lens and the optical axis in the direction parallel to the optical axis, and SAG12 is the distance from the maximum effective aperture of the image source side of the sixth lens to the intersection of the image source side of the sixth lens and the optical axis in the direction parallel to the optical axis.
6. The projection optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 3.3 < ΣCT / CT3 < 6.0; and / or 15.5 < BFL / ( T12+ T23) < 18.5; Wherein, ΣCT is the sum of the center thicknesses of the first lens, second lens, third lens, fourth lens, fifth lens and sixth lens in the optical system along the optical axis, CT3 is the center thickness of the third lens along the optical axis, BFL is the shortest distance along the optical axis from the image source side of the sixth lens to the image source surface of the optical system, T12 is the air gap between the first lens and the second lens on the optical axis, and T23 is the air gap between the second lens and the third lens on the optical axis.
7. The projection optical system according to claim 1, characterized in that: The optical system satisfies the following relationship: 1.0 < |(f3-f1) / f3| < 3.0; Where f1 is the effective focal length of the first lens and f3 is the effective focal length of the third lens.
8. The projection optical system according to claim 1, characterized in that: The optical system satisfies the following relationships: 1.6 < f / f345 < 1.9; and / or 2.2 < | (f23+f456) / f | < 5.0; Where f is the effective focal length of the optical system, f345 is the effective combined focal length of the third, fourth and fifth lenses, f23 is the combined focal length of the second and third lenses, and f456 is the combined focal length of the fourth, fifth and sixth lenses.
9. The projection optical system according to claim 1, characterized in that: The optical system has an F-number of ≤1.89 and a total optical length TTL of ≤12 mm.
10. A projection module, comprising at least an optical lens, characterized in that: The optical lens is equipped with a projection optical system according to any one of claims 1-9.