Projection lens module and miniature projection equipment

Abstract

The embodiment of the invention provides a projection lens module and micro projection equipment. The projection lens module sequentially comprises a first lens group, a diaphragm and a second lens group from an object side to an image side along an optical axis; the first lens group comprises a first doublet lens and a third lens which are arranged along the optical axis, the first doublet lens has positive focal power, the third lens has negative focal power, and the first doublet lens can move along the optical axis to adjust the focal length of the projection lens module; the second lens group comprises a second doublet lens, a third doublet lens and an eighth lens which are sequentially arranged along the optical axis, the second doublet lens, the third doublet lens and the eighth lens all have positive focal power, the third doublet lens can move along the optical axis, and the eighth lens can move along the optical axis. The third lens is used for compensating image plane displacement caused by movement of the third lens so as to keep clear imaging; the diaphragm is located between the third lens and the second doublet lens.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of projection optical display technology, and more specifically, to a projection lens module and a micro-projection device. Background Art

[0002] As a device commonly used in commercial display and advertising, the performance improvement of commercial micro projectors has always been the focus of the industry. In the design of projectors, focal length and field of view are two important parameters. Traditional commercial micro projectors usually adopt a design of long focal length and small field of view. This design meets the projection needs in specific scenarios to a certain extent, but it also brings some limitations.

[0003] First, it is difficult to achieve both a large projection ratio and a variable focal length in the design of existing micro projectors. A large projection ratio means that the projection lens can project a larger image within a shorter projection distance, while a variable focal length provides greater flexibility, allowing the projection lens to adapt to projection distances of different sizes. However, projection lenses in the prior art often find it difficult to achieve ideal results in both aspects.

[0004] Secondly, existing projection lenses are relatively large, with the maximum effective aperture exceeding 33mm. This is a significant disadvantage for commercial micro projectors, as one of the design goals of projectors is to pursue compactness. The large size increases the weight and space occupied by the equipment, and also increases the production cost.

[0005] In addition, insufficient correction of chromatic aberration and aberration is another problem of existing projection lenses. These optical defects will affect the clarity and color reproduction of the projected image, reduce the image quality, and thus affect the user's visual experience. Summary of the invention

[0006] The purpose of this application is to provide a new technical solution for a projection lens module and a micro-projection device.

[0007] In a first aspect, an embodiment of the present application provides a projection lens module, wherein the projection lens module includes a first lens group, an aperture and a second lens group in sequence from the image side to the object side along the optical axis; The first lens group includes a first doublet lens and a third lens arranged along the optical axis, the first doublet lens has positive focal power, and the third lens has negative focal power; The second lens group includes a second double-cemented lens, a third double-cemented lens and an eighth lens arranged in sequence along the optical axis, and the second double-cemented lens, the third double-cemented lens and the eighth lens all have positive focal power; The aperture is located between the third lens and the second doublet lens; The first double-cemented lens and the third double-cemented lens can be moved synchronously along the optical axis, and through the coordinated displacement of the two: The movement of the first doublet lens is used to adjust the focal length of the projection lens module; The movement of the third double cemented lens is used to compensate for the image plane displacement caused by the change of focal length.

[0008] Optionally, the central thickness T3 of the third lens and the total optical length TTL of the projection lens module satisfy: 8%<T3 / TTL<11.5%.

[0009] Optionally, the sag height at the maximum aperture on the image side of the third lens is S1, the sag height at the maximum aperture on the object side is S2, and the ratio of S1 to S2 satisfies: 1.2<S1 / S2<1.8.

[0010] Optionally, the angle between the tangent line at the maximum aperture of the object side surface of the third lens and the optical axis is A1, and the angle between the tangent line at the maximum aperture of the image side surface and the optical axis is A2, and A1 and A2 satisfy: 42°<(A1+A2) / 2<49°, and 0.85<A1 / A2<1.05.

[0011] Optionally, the sum T' of the center thicknesses of the first double-cemented lens, the second double-cemented lens, and the third double-cemented lens and the total optical length TTL of the projection lens module satisfy the following relationship: 16%<T' / TTL<33%.

[0012] Optionally, the central thickness T1 of the first double-cemented lens and the total optical length TTL of the projection lens module satisfy: 7%<T1' / TTL<14%.

[0013] Optionally, the first double-cemented lens is composed of a first lens and a second lens cemented together, wherein the first lens has positive optical power, the second lens has negative optical power, and the refractive index N1 of the first lens is lower than the refractive index N2 of the second lens.

[0014] Optionally, the first lens group satisfies: 10<(T3+T1) / T2<14; wherein T1 is the center thickness of the first lens, T2 is the center thickness of the second lens, and T3 is the center thickness of the third lens.

[0015] Optionally, the second doublet lens is formed by gluing a fourth lens and a fifth lens, wherein the fourth lens has positive power, the fifth lens has negative power, and a refractive index N4 of the fourth lens is lower than a refractive index N5 of the fifth lens; The third double-cemented lens is formed by cementing a sixth lens and a seventh lens, wherein the sixth lens has negative optical power, the seventh lens has positive optical power, and a refractive index N7 of the seventh lens is lower than a refractive index N6 of the sixth lens.

[0016] Optionally, the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy the following relationship: 3<(T4+T7) / (T5+T6)<4.8; wherein T4 is the center thickness of the fourth lens, T5 is the center thickness of the fifth lens, T6 is the center thickness of the sixth lens, and T7 is the center thickness of the seventh lens.

[0017] Optionally, the effective focal length of each lens in the projection lens module satisfies: The effective focal length of the first double cemented lens is F', 70mm≤F'≤90mm; The effective focal length of the third lens is F3, -20mm≤F3≤-13mm; The effective focal length of the second double cemented lens is F'', 600mm≤F''≤800mm; The effective focal length of the third double-cemented lens is F''', 25mm≤F'''≤37mm; The effective focal length of the eighth lens is F8, 52mm≤F8≤74mm; Each lens in the projection lens module is a glass spherical lens.

[0018] Optionally, the projection lens module further includes a galvanometer, a prism, a glass plate and a display unit which are located on the object side of the eighth lens and are arranged in sequence; The ratio of the total optical length TTL of the projection lens module to the maximum aperture D1 of the lens in the projection lens module satisfies: 1.7<TTL / D1<2.7.

[0019] Optionally, the total optical length TTL of the projection lens module is 59 mm<TTL<85 mm, and the maximum effective aperture is 33 mm.

[0020] Optionally, the optical parameters of the projection lens module include: focal length of 21mm~32mm, projection ratio TR of 4~6, relative aperture of 1 / 1.73, Offset: 0%, pixel size of 5.4μm, field of view angle of 5.2°~8.1°, image plane size of 5.5mm~6.5mm, and operating band of 455nm~630nm.

[0021] In a second aspect, an embodiment of the present application provides a micro-projection device, wherein the micro-projection device comprises: casing; and A projection lens module as described in the second aspect.

[0022] The beneficial effects of this application are: The projection lens module provided in the embodiment of the present application can adjust the focal length of the entire projection lens module by moving the first double-cemented lens, so that the size of the projection image can be adjusted within a focal length range of, for example, 21 mm to 32 mm, thereby meeting the projection requirements in different scenes. At the same time, the synchronous movement of the third double-cemented lens can be used to compensate for the image plane displacement caused by the change in the focal length of the first double-cemented lens, ensuring the stability of the imaging surface during the zooming process and avoiding the image blur phenomenon.

[0023] The optical power combination design of the first lens group "positive optical power double-cemented lens with negative optical power single lens" and the second lens group with full positive optical power adopted in the embodiment of the present application can effectively correct aberration problems such as field curvature and spherical aberration, laying the foundation for high-quality imaging. The coordinated work between the three positive optical power elements in the second lens group and the movable third double-cemented lens further corrects the chromatic aberration problems that may occur during the zooming process, so that the projection lens module can maintain excellent optical performance throughout the zoom range and ensure the clarity of the projected image. In addition, the reasonable setting of the aperture position not only optimizes the optical performance of the projection lens module, but also improves the structural compactness of the projection lens module.

[0024] In summary, the projection lens module provided in the embodiments of the present application not only realizes the adjustment of focal length, but also ensures excellent optical performance and compact structure, bringing a good visual experience to users.

[0025] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0027] Figure 1 A schematic diagram of the optical architecture of a projection lens module provided in an embodiment of the present application; Figure 2 A schematic diagram of a partial structure of a third lens of a projection lens provided in an embodiment of the present application; Figure 3 for Figure 1 Distortion diagram of the provided projection lens module; Figure 4 for Figure 1 The MTF diagram of the provided projection lens module; Figure 5 for Figure 1Dot array diagram of the provided projection lens module; Figure 6 for Figure 1 Provide vertical axis chromatic aberration diagram of the projection lens module; Figure 7 The structure and optical path diagram of the projection lens module provided in Example 1 of the present application; Figure 8 for Figure 7 Dot array diagram of the provided projection lens module; Fig. 9 for Figure 7 The MTF diagram of the provided projection lens module; Fig.10 for Figure 7 Field curvature and distortion diagrams of the provided projection lens modules; Fig.11 for Figure 7 Vertical axis chromatic aberration diagram of the provided projection lens module; Fig.12 The structure and optical path diagram of the projection lens module provided in Example 2 of the present application; Fig.13 for Fig.12 Dot array diagram of the provided projection lens module; Fig.14 for Fig.12 The MTF diagram of the provided projection lens module; Fig.15 for Fig.12 Field curvature and distortion diagrams of the provided projection lens modules; Fig.16 for Fig.12 Provide vertical axis chromatic aberration diagram of the projection lens module; Fig.17 The structure and optical path diagram of the projection lens module provided in Example 3 of the present application; Fig.18 for Fig.17 Dot array diagram of the provided projection lens module; Fig.19 for Fig.17 The MTF diagram of the provided projection lens module; Fig. 20 for Fig.17 Field curvature and distortion diagrams of the provided projection lens modules; Fig.21 for Fig.17 Vertical axis chromatic aberration diagram of the provided projection lens module; Fig. 22 This is a diagram showing the correspondence between the focal length of the projection lens module and the air gap A, air gap B and air gap C provided in an embodiment of the present application.

[0028] Description of reference numerals: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Aperture; 10. Galvanometer; 11. Prism; 12. Display unit; 13. Glass plate. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0030] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0031] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0032] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0033] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0034] The projection lens module and the micro-projection device provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0035] According to an embodiment of the present application, a projection lens module is provided. Figure 1 , the projection lens module includes a first lens group, an aperture 9 and a second lens group in sequence from the image side to the object side along the optical axis. The first lens group includes a first double-cemented lens and a third lens 3 arranged along the optical axis, wherein the first double-cemented lens has positive focal power and the third lens 3 has negative focal power. The second lens group includes a second double-cemented lens, a third double-cemented lens and an eighth lens 8 arranged in sequence along the optical axis, wherein the second double-cemented lens, the third double-cemented lens and the eighth lens 8 all have positive focal power. The aperture 9 is located between the third lens 3 and the second double-cemented lens. In the projection lens module of the embodiment of the present application, see Figure 7 , Fig.12 and Fig.17The first double-cemented lens and the third double-cemented lens can move synchronously along the optical axis, and through the coordinated displacement of the two: the movement of the first double-cemented lens is used to adjust the focal length of the projection lens module; the movement of the third double-cemented lens is used to compensate for the image plane displacement caused by the change of focal length.

[0036] That is to say, the projection lens module provided in the embodiment of the present application is a variable-focus optical design that can achieve a focusing effect.

[0037] The projection lens module provided in the embodiment of the present application is shown in FIG. Figure 1 , its main components include a projection lens and a display unit 12. The projection lens includes the above-mentioned first lens group, the second lens group and the diaphragm 9 located between the two lens groups (the position of the diaphragm 9 is fixed, that is, the air gap between the diaphragm 9 and the lenses on both sides is fixed). The projection lens is located on the light path of the display unit 12, and is responsible for receiving the light emitted from the display unit 12 (these light rays are dedicated to projection display) and performing processes such as modulation and focusing on these light rays. Through this series of optical effects, the light emitted by the display unit 12 can be guided and projected onto the imaging surface, and finally present a clear projection picture.

[0038] See also Figure 1 The projection lens module provided in the embodiment of the present application includes a first lens group, a second lens group and an aperture 9. The first lens group (in Figure 1 Compared with the second lens group, it is further away from the display unit 12 in the projection lens module. Figure 1 The aperture 9 is located between the first lens group and the second lens group, and is mainly used to optimize the transmission path of light to further improve the imaging effect.

[0039] It should be noted that see Figure 1 In the optical design of the present application, the side where the display unit 12 is located is defined as the object side, and the side away from the display unit 12 is defined as the image side. That is, the first lens group is close to the image side, and the second lens group is close to the object side.

[0040] The first lens group provided in the embodiment of the present application is described in detail as follows.

[0041] The first lens group provided in the embodiment of the present application is one of the components of the entire projection lens module (or projection lens). The first lens group is mainly composed of a first doublet lens and a single third lens 3, which each play an important role in the entire projection lens module.

[0042] Specifically, in the first lens group: the first double-cemented lens is designed to be composed of two lenses (such as the first lens 1 and the second lens 2) through a bonding process to form an integral optical element. In addition, the first double-cemented lens is designed to have a positive optical power (i.e., a positive lens), which is mainly used to converge light and can enhance the light collection ability of the entire projection lens module. The optical power of the third lens 3 is different from that of the first double-cemented lens, and the third lens 3 is designed to have a negative optical power, which can be used to diverge light.

[0043] In particular, in the first lens group, the first doublet lens is designed to be movable along the optical axis to change the air gap A between the first doublet lens and the third lens 3. As the first doublet lens moves along the optical axis toward or away from the third lens 3, the focal length of the projection lens module can be adjusted. In other words, this design allows the focal length of the projection lens module to be changed by adjusting the position of the first doublet lens on the optical axis, thereby achieving a zoom function.

[0044] In one example, see Figure 7 , the first double-cemented lens moves along the optical axis to a position away from the third lens 3. At this time, the air gap A between the first double-cemented lens and the third lens 3 is large, and the focal length of the projection lens module is about 32.3 mm. In this example, the projection lens module is in a telephoto state.

[0045] In another example, see Fig.17 , the first double cemented lens moves along the optical axis to a position close to the third lens 3, at which time, the air gap A between the first double cemented lens and the third lens 3 is significantly reduced (compared to Figure 7 ), the focal length of the projection lens module becomes about 21.3m. In this example, the projection lens module is in a short-focus state.

[0046] In another example, see Fig.12 , the first double-cemented lens moves along the optical axis to a position different from the above two examples, at this time, the air gap A between the first double-cemented lens and the third lens 3 is compared with Figure 7 The air gap A shown in the figure is smaller than Fig.17 The air gap A shown in FIG. 1 is larger. In this example, the projection lens module is in a mid-focus state.

[0047] The embodiment of the present application provides a projection lens module, and by moving the first double-cemented lens along the optical axis, the focal length of the entire projection lens module is adjusted. For example, the projection lens module provided by the embodiment of the present application can cover a focal length range of 21mm to 32mm, see Fig. 22.

[0048] It should be noted that, during the zooming process, the movement of a single lens (even a glued lens) can hardly meet the requirements of focal length change and image plane stability of the entire module at the same time. Therefore, the collaborative movement mechanism of the first double glued lens and the third double glued lens is adopted in the present application. In short, when the first double glued lens moves along the optical axis to adjust the focal length of the module, the synchronous movement of the third double glued lens can compensate for the image plane displacement caused by the focal length change. This multi-lens collaborative working mode in the embodiment of the present application ensures the stability of the imaging plane during the zooming process and maintains clear imaging even when the focal length changes. Since the synchronously moving third double glued lens is located in the second lens group, the third double glued lens will be described in detail in the description of the second lens group.

[0049] The second lens group provided in the embodiment of the present application is described in detail as follows.

[0050] The second lens group provided in the embodiment of the present application is another component of the projection lens module (or projection lens), which also plays an important optical role in the imaging process. The second lens group is mainly composed of a second double-cemented lens, a third double-cemented lens and a single eighth lens 8, each of which has a specific optical function. In the second lens group, all lenses have positive focal lengths, and they converge light together to form a clear image on the imaging surface.

[0051] Specifically, in the second lens group: the second double-cemented lens is composed of two lenses (such as the fourth lens 4 and the fifth lens 5) through a bonding process to form an integral optical element. The second double-cemented lens is designed to have positive focal length, which can effectively converge light and further enhance the focusing effect of light. The third double-cemented lens is also formed by bonding two lenses (such as the sixth lens 6 and the seventh lens 7). The third double-cemented lens is also designed to have positive focal length. In addition, the third double-cemented lens is designed to be able to move synchronously with the first double-cemented lens along the optical axis.

[0052] It should be noted that during the zooming process of the projection lens module, the change in focal length often causes displacement of the image plane, affecting the image quality. In the embodiment of the present application, by synchronously moving the third double-cemented lens, the image plane displacement caused by the change in focal length of the first double-cemented lens is effectively compensated. This design ensures the stability of the imaging plane during the zooming process, avoids image blur, and ensures a high-quality projection effect.

[0053] In the second lens group, the eighth lens 8 is designed as a positive lens, which works in coordination with other lenses (especially the second double-cemented lens and the third double-cemented lens in the same lens group). Specifically, the main functions of the eighth lens 8 are embodied in the following two aspects: In the first aspect, the eighth lens 8 is a positive lens and has the ability to converge light. It works in conjunction with the second double-cemented lens and the third double-cemented lens to enhance the light convergence effect of the second lens group. This enhancement helps ensure that light can be more accurately focused on the imaging surface, thereby improving the clarity of the projected image.

[0054] On the second aspect, the positive power characteristic of the eighth lens 8 not only helps to converge light, but also can correct aberrations to a certain extent, such as spherical aberration and chromatic aberration, etc. The eighth lens 8 can further optimize the imaging quality and ensure the color reproduction of the projected image by matching with the second double-cemented lens and the third double-cemented lens in the same lens group.

[0055] Based on the optical design of the eighth lens 8, the projection lens module can maintain high-quality imaging effects during zooming. In short, no matter how the focal length of the projection lens module changes, the eighth lens 8 can accurately focus the light on the imaging surface, thereby forming a high-quality projection image.

[0056] Please continue to see Figure 1 In the projection lens module, the aperture 9 is designed to be located between the third lens 3 and the second double-cemented lens. It is mainly used to limit the range of light passing through, control the size of the imaging beam, and help improve the imaging quality.

[0057] The projection lens module provided in the embodiment of the present application is shown in FIG. Figure 7 , Fig.12 and Fig.17 In the first lens group, the first double-cemented lens can move along the optical axis to get closer to or farther away from the third lens 3, which realizes the adjustment of the air gap A, thereby realizing the change of the focal length of the projection lens module. At the same time, the third double-cemented lens in the second lens group also has the ability to move along the optical axis, and is designed to move synchronously with the first double-cemented lens. By synchronously adjusting the position of the third double-cemented lens on the optical axis, the air gap B between the third double-cemented lens and the second double-cemented lens, and the air gap C between the third double-cemented lens and the eighth lens 8 can be changed. This lens movement mechanism in the present application not only ensures the stability of the optical performance during the zooming process, but also effectively compensates for the image plane displacement caused by the change of focal length, thereby maintaining the clarity and imaging quality of the projection picture within the entire zoom range.

[0058] See also Fig. 22 The focal length range of the projection lens module provided in the embodiment of the present application is, for example, 21.3 mm to 32.3 mm, and its zoom ratio is 1.5X.

[0059] The projection lens module provided in the embodiment of the present application can adjust the focal length of the entire projection lens module by moving the first double-cemented lens, so that the size of the projection image can be adjusted within a focal length range of, for example, 21 mm to 32 mm, thereby meeting the projection requirements in different scenes. At the same time, the synchronous movement of the third double-cemented lens can be used to compensate for the image plane displacement caused by the change in the focal length of the first double-cemented lens, ensuring the stability of the imaging surface during the zooming process and avoiding the image blur phenomenon.

[0060] The optical power combination design of the first lens group "positive optical power double-cemented lens with negative optical power single lens" and the second lens group with full positive optical power adopted in the embodiment of the present application can effectively correct aberration problems such as field curvature and spherical aberration, laying the foundation for high-quality imaging. The coordinated work between the three positive optical power elements in the second lens group and the movable third double-cemented lens further corrects the chromatic aberration problems that may occur during the zooming process, so that the projection lens module can maintain excellent optical performance throughout the zoom range and ensure the clarity of the projected image. In addition, the reasonable setting of the aperture position not only optimizes the optical performance of the projection lens module, but also improves the structural compactness of the projection lens module.

[0061] In summary, the projection lens module provided in the embodiments of the present application not only realizes the adjustment of focal length, but also ensures excellent optical performance and compact structure, bringing a good visual experience to users.

[0062] In addition, the projection lens module provided in the embodiment of the present application, wherein the projection lens only adopts an 8-lens design, see Figure 1 , and through the reasonable setting of the aperture 9 and the lens arrangement sequence (such as reasonable optical focal length distribution), the compactness of the optical structure is achieved. This design makes the projection lens module of the embodiment of the present application suitable for space-constrained application scenarios such as commercial micro projectors.

[0063] The projection lens module provided in the embodiment of the present application has a projection ratio that is adjustable within a range of 4 to 6 during the zooming process.

[0064] In some examples of this application, see Figure 1 The third lens 3 is a lens with a larger thickness in the first lens group, that is, the third lens 3 is designed as a thick lens. The central thickness T3 of the third lens 3 and the total optical length TTL of the projection lens module satisfy: 8%<T3 / TTL<11.5%.

[0065] In the example provided in this application, the third lens 3 is not only designed to be the thickest lens in the first lens group, but also designed to satisfy a specific proportional relationship between its center thickness T3 and the total optical length TTL of the projection lens module, that is, 8%<T3 / TTL<11.5%. This optical design has obvious advantages in reducing the field curvature of the projection lens module, as analyzed below.

[0066] Field curvature is a type of aberration that needs to be controlled, otherwise it will affect the image quality.

[0067] In the projection lens module provided in the embodiment of the present application, the third lens 3 is one of the thick lenses, and its larger center thickness can provide better light modulation capability, which is helpful to correct the field curvature. In the example provided in the present application, by further designing the ratio between the center thickness T3 and TTL of the third lens 3 to be between 8% and 11.5%, the center thickness range of the third lens 3 can be better controlled, so that it has sufficient light modulation capability, effectively corrects the field curvature of the projection lens module, and thus improves the imaging quality of the entire projection lens module.

[0068] In the example provided in the present application, by properly controlling the central thickness T3 of the third lens 3, not only the field curvature is reduced, but also other aberrations such as spherical aberration, chromatic aberration, etc. are positively affected.

[0069] The third lens 3 is one of the main lenses in the first lens group. Its fixed position and specific design (such as thick lens design) play a role in stabilizing optical performance during the zooming process.

[0070] As mentioned above, the design of the center thickness T3 of the third lens 3 helps to correct the field curvature. During the zooming process, although the focal length is changing, the correction effect of the third lens 3 on the field curvature still exists. This helps to ensure that the edges of the projected image remain clear even at different focal lengths.

[0071] In the projection lens module provided in the embodiment of the present application, the third lens 3 also works together with other lenses, especially the first double-cemented lens and the third double-cemented lens, to jointly correct aberrations. Although it does not move during the zooming process, its inherent optical properties still have a positive effect on the correction of aberrations. This helps to improve the overall clarity and color reproduction of the projected image.

[0072] In addition, the proportional relationship provided in this example of the present application well controls the center thickness of the third lens 3, making its center thickness appropriate without affecting the volume and weight of the projection lens module.

[0073] In some examples of this application, see Figure 1 The sagitta of the third lens 3 at the maximum aperture on the image side is S1, and the sagitta of the third lens 3 at the maximum aperture on the object side is S2, and the ratio of S1 to S2 satisfies: 1.2<S1 / S2<1.8.

[0074] In the example provided in the present application, the third lens 3 is a negative lens, and the ratio between the sagittal height S1 of the image side (i.e., the side away from the display unit 12) and the sagittal height S2 of the object side (i.e., the side close to the display unit 12) of the third lens 3 is designed. This optical design reflects the further control of the surface shape of the third lens 3, aiming to further optimize the overall performance of the projection lens module.

[0075] By adjusting the ratio range of S1 to S2, the refraction and other properties of the third lens 3 on light can be controlled, so as to more effectively correct aberrations, especially aberrations such as field curvature. These aberrations often cause image edges to be blurred or deformed. By adjusting the ratio range of S1 to S2, the third lens 3 can provide excellent aberration correction effects at different field angles, thereby improving the overall clarity and detail expression of the projected image.

[0076] By controlling the ratio range of S1 to S2 of the third lens 3, it is possible to ensure that the propagation path of light remains stable during the zooming process. This helps to reduce image blur and distortion caused by focal length changes and improve stability and reliability during the zooming process. In addition, by adjusting the ratio range of S1 to S2 of the third lens 3, the volume and weight of the entire projection lens module can be reduced while ensuring optical performance.

[0077] In some examples of this application, see Figure 2 The angle between the tangent line at the maximum aperture of the object side of the third lens 3 and the optical axis is A1, and the angle between the tangent line at the maximum aperture of the image side and the optical axis is A2, and A1 and A2 satisfy: 42°<(A1+A2) / 2<49°, and 0.85<A1 / A2<1.05.

[0078] In the example provided in this application, the surface shape of the third lens 3 is more finely regulated. The angles between the tangent line of the object side (the side close to the display unit 12) and the image side (the side away from the display unit 12) of the third lens 3 at the maximum aperture and the optical axis are set to A1 and A2, respectively. Figure 2 The two angles A1 and A2 are further designed to simultaneously satisfy two optical conditions: 42°<(A1+A2) / 2<49°, and 0.85<A1 / A2<1.05. This optical design not only reflects the optimized design of the three-face shape of the third lens, but also aims to optimize the optical performance of the projection lens module.

[0079] Through this design in this example of the present application, the third lens 3 can better control the propagation path and refraction angle of the light, effectively reduce the generation of aberrations such as field curvature, and thus significantly improve the clarity, contrast and color reproduction of the projected image. In addition, the regulation of the geometric characteristics of this lens also helps to enhance the optical stability during the zoom process, thereby ensuring that the projected image can maintain excellent imaging quality at different focal lengths.

[0080] In general, this example of the present application brings more excellent optical performance and more stable and reliable imaging performance to the projection lens module by further optimizing the three-surface shape of the third lens.

[0081] In some examples of the present application, the sum T' of the center thicknesses of the first doublet lens, the second doublet lens, and the third doublet lens and the total optical length TTL of the projection lens module satisfy the following relationship: 16%<T' / TTL<33%.

[0082] In the example provided in this application, a specific proportional relationship between the sum of the center thicknesses T' of the first double-cemented lens, the second double-cemented lens, and the third double-cemented lens and the total optical length TTL of the projection lens module is described, that is, 16%<T' / TTL<33%. This design reflects the control of the thickness of the three groups of double-cemented lenses used inside the projection lens module, aiming to further optimize the imaging performance, zoom stability, and overall compactness of the projection lens module.

[0083] By controlling the ratio of the sum of the center thicknesses T' of the three sets of double-cemented lenses mentioned above to the total optical length TTL of the entire projection lens module, the light propagation path and refraction angle inside the projection lens module can be effectively adjusted, thereby optimizing various aberration corrections and significantly improving the clarity, contrast and detail expression of the projected image, so as to achieve the purpose of optimizing the imaging performance of the projection lens module. Moreover, under the premise of ensuring optical performance, by controlling the ratio of the sum of the center thicknesses T' of the three sets of built-in double-cemented lenses to the total optical length TTL, it is also helpful to achieve the structural compact design of the projection lens module.

[0084] In some examples of the present application, the central thickness T1' of the first double-cemented lens and the total optical length TTL of the projection lens module satisfy: 7%<T1' / TTL<14%.

[0085] In the example provided in this application, a specific proportional relationship between the center thickness T1' of the first double-cemented lens and the total optical length TTL of the projection lens module is described, that is, 7%<T1' / TTL<14%. It is worth noting that the first double-cemented lens can be moved along the optical axis, and this design gives the projection lens module the function of focusing.

[0086] In the present application, by reasonably controlling the ratio of the center thickness T1' of the first double cemented lens to the total optical length TTL of the projection lens module, the light propagation path and refraction angle inside the projection lens module can be optimized, thereby improving the aberration correction effect. This not only helps to improve the clarity, contrast and color reproduction of the projected image, but also provides a good foundation for the focusing function.

[0087] The first double-cemented lens moves along the optical axis, so that the entire projection lens module can be focused. This focusing function ensures that the projection image can maintain the best focus state in different application scenarios, which helps to improve the imaging quality. In addition, by further controlling the ratio range of T1' / TTL, it can ensure that the optical performance of the projection lens module remains stable during the zooming process, reducing the occurrence of image blur and distortion. This not only improves the smoothness and accuracy of the zoom, but also enhances the imaging consistency of the projection lens module at different focal lengths. In addition, under the premise of ensuring optical performance and focusing function, by controlling the ratio of the center thickness T1' of the first double-cemented lens to the total optical length TTL of the projection lens module, it helps to achieve a compact structural design of the projection lens module.

[0088] In some examples of this application, see Figure 1 The first double-cemented lens is composed of a first lens 1 and a second lens 2 cemented together, wherein the first lens 1 has positive optical power, the second lens 2 has negative optical power, and the refractive index N1 of the first lens 1 is lower than the refractive index N2 of the second lens 2.

[0089] In the example provided in the present application, the first double-cemented lens is bonded together by a low-refractive-index positive lens and a high-refractive-index negative lens, and this design can effectively correct chromatic aberration. This is because after the low-refractive-index positive lens and the high-refractive-index negative lens are bonded together, light of different wavelengths can produce different deflection angles when passing through the bonded lens, thereby achieving chromatic aberration correction on the imaging surface.

[0090] Specifically, the refractive index N1 of the first lens 1 (a positive lens) is lower than the refractive index N2 of the second lens 2 (a negative lens). This combination is conducive to eliminating chromatic aberration in the visible light range and improving the color reproduction and clarity of imaging. Based on this positive-negative bonding design, the first double bonded lens can significantly improve the imaging quality while maintaining a high light transmittance.

[0091] Since the first double-cemented lens can effectively correct chromatic aberration and other aberrations, the projection lens module can maintain more stable imaging quality under different working environments and usage conditions. This is particularly important for commercial micro projectors, which need to provide high-quality projection effects under various complex environmental conditions.

[0092] In one example, in the first double-cemented lens: the refractive index N1 of the first lens 1 (positive lens) is in the range of 1.59 to 1.8, and the refractive index N2 of the second lens 2 (negative lens) is in the range of 1.74 to 1.85. The refractive index ranges of the positive lens and the negative lens in the first lens group are set in this example mainly in consideration of the manufacturing cost and processing difficulty of the lens, while taking into account both the optical performance and the manufacturing feasibility.

[0093] In some examples of the present application, the first lens group satisfies: 10<(T3+T1) / T2<14; wherein T1 is the center thickness of the first lens 1, T2 is the center thickness of the second lens 2, and T3 is the center thickness of the third lens 3.

[0094] See also Figure 1 In the first lens group, the center thicknesses of the first lens 1 and the third lens 3 are both relatively large, and they are two thick lenses in the first lens group. The center thickness T2 of the second lens 2 is smaller than that of the first lens 1 and the third lens 3, and it is a thin lens in the first lens group. In other words, the first lens group uses two thick lenses and one thin lens.

[0095] In this example of the present application, by adjusting the ratio between the total center thickness of two thick lenses and the center thickness of one thin lens, it helps to optimize aberration correction, especially for key aberrations such as field curvature and spherical aberration. The combination of two thick lenses and one thin lens can more accurately control the refraction angle and propagation path of light, reduce the impact of aberrations on imaging quality, and improve the clarity and contrast of the picture.

[0096] In particular, during the zooming process, the three lenses in the first lens group work together to maintain a stable propagation path of light. By controlling the range of (T3+T1) / T2, it is possible to ensure that the optical performance of the projection lens module remains stable during the zooming process, reduce image blur and distortion, and improve the accuracy of zooming.

[0097] In some examples of this application, see Figure 1The second double-cemented lens is composed of a fourth lens 4 and a fifth lens 5, wherein the fourth lens 4 has positive power, the fifth lens 5 has negative power, and the refractive index N4 of the fourth lens 4 is lower than the refractive index N5 of the fifth lens 5. The third double-cemented lens is composed of a sixth lens 6 and a seventh lens 7, wherein the sixth lens 6 has negative power, the seventh lens 7 has positive power, and the refractive index N7 of the seventh lens 7 is lower than the refractive index N6 of the sixth lens 6.

[0098] In one example, in the second doublet lens: the refractive index N4 of the fourth lens 4 (positive lens) is in the range of 1.59 to 1.8, and the refractive index N5 of the fifth lens 5 (negative lens) is in the range of 1.74 to 1.85.

[0099] In one example, in the third doublet lens: the refractive index N4 of the seventh lens 7 (positive lens) is in the range of 1.59 to 1.8, and the refractive index N6 of the sixth lens 6 (negative lens) is in the range of 1.74 to 1.85.

[0100] In the projection lens module provided in the embodiment of the present application, see Figure 1 , a total of three double-cemented lenses are used, namely, a combination design of a first double-cemented lens, a second double-cemented lens, and a third double-cemented lens. This combination design of optical elements greatly improves the overall performance of the projection lens module. The following is a specific analysis of the design technology effect in this application.

[0101] One of the core advantages of double-glued lenses is their excellent chromatic aberration correction ability. By gluing a high-refractive-index negative lens with a low-refractive-index positive lens together, the double-glued lens formed in this way can effectively compensate for the dispersion differences caused by light of different wavelengths passing through the lens, thereby achieving correction of chromatic aberration in the visible light range. In the projection lens module provided in the embodiment of the present application, the combination of three groups of double-glued lenses enhances this advantage. Each group of double-glued lenses can perform chromatic aberration correction for light of a specific wavelength, and the combination of the three can cover a wider spectral range, providing a more comprehensive and accurate chromatic aberration correction effect. This not only ensures a high degree of color reproduction of the projected image, but also ensures that the edge image is also relatively clear, greatly improving the overall visual experience.

[0102] In addition to chromatic aberration correction, the use of double-cemented lenses can also optimize other types of aberrations, such as spherical aberration, astigmatism, etc. In the projection lens module design of the present application, the combination of three groups of double-cemented lenses enables light to be more comprehensively modulated when passing through the projection lens module, thereby achieving a significant improvement in the overall imaging quality.

[0103] In addition, since the projection lens module of the present application has the characteristics of a large projection ratio (4~6) and a variable focal length (21~32mm), the combination of three groups of double-cemented lenses provides optical support for achieving this design goal, ensuring that high-quality projection images can be obtained at different focal lengths and projection ratios.

[0104] In some examples of the present application, the fourth lens 4, the fifth lens 5, the sixth lens 6 and the seventh lens 7 satisfy the following: 3<(T4+T7) / (T5+T6)<4.8; wherein T4 is the center thickness of the fourth lens 4, T5 is the center thickness of the fifth lens 5, T6 is the center thickness of the sixth lens 6, and T7 is the center thickness of the seventh lens 7.

[0105] In the second lens group provided in the embodiment of the present application, the center thicknesses of the fourth lens 4 and the seventh lens 7 are both relatively large, and they are two thick lenses in the second lens group. The center thicknesses of the fifth lens 5 and the sixth lens 6 are relatively small, and they are two thin lenses in the second lens group.

[0106] In this example of the present application, by adjusting the ratio between the sum of the center thickness of the two thick lenses and the sum of the center thickness of the two thin lenses in the second lens group, it is helpful to optimize the aberration correction. The reasonable combination of thick lenses and thin lenses can more accurately control the refraction angle and propagation path of light, reduce the impact of aberrations on imaging quality, and improve the clarity and contrast of the picture.

[0107] In particular, by controlling the condition of 3<(T4+T7) / (T5+T6)<4.8, it is possible to ensure that the optical performance of the projection lens module remains stable during the zooming process while improving the accuracy of the zooming.

[0108] In some examples of the present application, the effective focal length of each lens in the projection lens module satisfies: The effective focal length of the first double cemented lens is F', 70mm≤F'≤90mm; The effective focal length of the third lens 3 is F3, -20mm≤F3≤-13mm; The effective focal length of the second double cemented lens is F'', 600mm≤F''≤800mm; The effective focal length of the third double-cemented lens is F''', 25mm≤F'''≤37mm; The effective focal length of the eighth lens 8 is F8, 52mm≤F8≤74mm.

[0109] In the first lens group, the first double-cemented lens is the front group part of the entire projection lens module (it is located on the image side, away from the display unit 12), and its effective focal length range ensures that the projection lens module can have a certain convergence ability to form a clear image within a shorter focal length. This helps to achieve high-quality projection effects in a limited space. Especially in commercial micro projectors, the requirements for compactness and high performance are particularly important.

[0110] The effective focal length F3 range of the third lens 3 is designed to be -20mm≤F3≤-13mm. The third lens 3 is a part of the first lens group (the front group of the projection lens module). This design range enables the projection lens module to better adapt to the requirements of different projection ratios and focal lengths, while reducing field curvature and improving imaging quality.

[0111] In the second lens group, the effective focal length F'' of the second double-cemented lens is designed to be 600mm≤F''≤800mm. As part of the rear group of the projection lens module (it is located on the object side, close to the display unit 12), the long focal length design of the second double-cemented lens helps to further amplify and correct the light passing through the front group. This long focal length design range, combined with the combination of high refractive index and low refractive index lenses, can effectively correct chromatic aberration and improve the color reproduction and clarity of the projected image.

[0112] The effective focal length F''' of the third double-cemented lens is designed to be 25mm≤F'''≤37mm. The third double-cemented lens is also part of the rear group of the projection lens module. Its focal length design range helps to adjust the light passing through the first lens group and the second double-cemented lens, further optimizing the imaging quality. In addition, the design of the third double-cemented lens also takes into account thermal stability and mechanical stability to ensure that a stable projection effect can be maintained under different working conditions.

[0113] The effective focal length F8 of the eighth lens 8 is designed to be in the range of 52 mm ≤ F8 ≤ 74 mm. The focal length range of the eighth lens 8 can ensure that the projection image forms a clear projection image on the imaging surface.

[0114] Through the specially designed lens effective focal length range, the projection lens module of the present application has achieved remarkable technical effects in chromatic aberration correction, imaging quality improvement, light path optimization, etc.

[0115] In some examples of the present application, each lens in the projection lens module is a spherical lens.

[0116] Specifically, each lens in the projection lens module is designed as a glass spherical lens.

[0117] Glass spherical lenses can meet the high imaging quality requirements of projection lens modules, while the manufacturing cost is relatively low, which is conducive to reducing the production cost of projection lens modules. Glass spherical lenses have good optical properties, can reduce the scattering and absorption of light, and improve the clarity and contrast of imaging. In addition, glass materials have high thermal and chemical stability, and can maintain stable optical properties under different environmental conditions, which helps to enhance the stability of the entire projection lens module and improve the reliability and service life of the product.

[0118] In some examples of this application, see Figure 1 The projection lens module also includes a galvanometer 10 and a prism 11 which are located on the object side of the eighth lens 8 and are arranged in sequence.

[0119] In some examples of this application, see Figure 1 The projection lens module further includes a display unit 12 and a glass plate 13 , and the glass plate 13 is located between the display unit 12 and the prism 11 .

[0120] In some examples of the present application, the ratio of the total optical length TTL of the projection lens module to the maximum aperture D1 of the lens in the projection lens module satisfies: 1.7<TTL / D1<2.7.

[0121] That is to say, the projection lens module provided in the embodiment of the present application not only includes two lens groups and an aperture 9, but also introduces a series of optical elements such as a galvanometer 10, a prism 11, a glass plate 13 and a display unit 12, and specifically stipulates a ratio range between the total optical length TTL of the projection lens module and the maximum aperture D1 of the lens (1.7<TTL / D1<2.7).

[0122] See also Figure 1 In the projection lens module, the aperture of the first lens 1 is the largest.

[0123] In the projection lens module of the embodiment of the present application, whether the galvanometer 10 is provided depends on specific application requirements.

[0124] The prism 11 can be used to further adjust the direction of the light. By properly designing the shape and angle of the prism, the light path can be precisely controlled to meet specific projection requirements. The prism 11 can be designed as a total internal reflection prism (TIR prism).

[0125] The display unit 12 is one of the components of the projection lens module, which is responsible for generating and providing light for projection imaging to the projection lens. The display unit 12 is, for example, a high-resolution display device such as LCD, DLP or LCOS, which can generate high-quality image signals.

[0126] The glass plate 13 is placed between the display unit 12 and the prism 11 to ensure that the light emitted from the display unit 12 can efficiently pass through the subsequent prism and lens group to finally form a high-quality projection image. The glass plate 13 reduces the loss and interference of light during transmission through its high light transmittance and low reflectivity, which is conducive to improving the brightness and contrast of the projection image.

[0127] In some examples provided in this application, the design of TTL / D1 ranging from 1.7 to 2.7 is a key balance between the compactness and optical performance of the projection lens module. A smaller ratio means that the projection lens module can be more compact, which is conducive to reducing the overall volume and weight of the projection device. A larger ratio may provide a larger design space and help optimize optical performance. By controlling this ratio range, this application ensures both the compactness of the projection lens module and its excellent optical performance.

[0128] In some examples of this application, see Figure 1 The total optical length TTL of the projection lens module is 59mm<TTL<85mm, and its maximum effective aperture is 33mm.

[0129] By controlling the total optical length TTL between 59mm and 85mm, it is possible to provide sufficient space for optical design while ensuring the compactness of the projection lens module to achieve high-quality imaging effects. The maximum effective aperture of 33mm ensures that the projection lens module has sufficient light transmission to provide clear projection images under different lighting conditions.

[0130] In some examples of this application, see Figure 1 As shown in Table 1, the main parameters of the projection lens module include: focal length of 21mm~32mm, projection ratio TR of 4~6, relative aperture: 1 / 1.73, Offset: 0%, pixel size: 5.4μm, field of view angle of 5.2°~8.1°, image plane size of 5.5mm~6.5mm, working band of 455nm~630nm, image plane size: 5.5mm~6.5mm.

[0131] See Table 1, which shows Figure 1 Some main optical parameters of the projection lens module provided.

[0132] Table 1

[0133] The focal length of the projection lens module provided in the embodiment of the present application is 21 mm to 32 mm. Fig. 22 , which covers a wide focal length range, so that the projection lens module can adapt to the needs of different projection distances and screen sizes. The projection ratio of the projection lens module reaches 4~6, which means that at the same projection distance, a larger screen can be projected to meet the needs of large venues or long-distance projection.

[0134] The relative aperture of the projection lens module provided in the embodiment of the present application is 1 / 1.73, which ensures a sufficient aperture size so that the projection lens module can provide a bright projection image even in a low-light environment.

[0135] The Offset of the projection lens module provided in the embodiment of the present application is 0%, which means that the projection image remains perpendicular to the projector lens, thus avoiding the problem of image offset.

[0136] The pixel size of the projection lens module provided in the embodiment of the present application is 5.4 μm, which ensures the fineness and clarity of the projected image and can present delicate image details.

[0137] The operating band is 455nm~630nm, which covers most of the range of visible light, so that the projection lens module provided by the embodiment of the present application can present rich colors and natural picture effects.

[0138] The field of view is 5.2~8.1°, which is not particularly large, but provides a certain viewing angle range while ensuring image quality. This field of view design meets the needs of commercial micro-projection equipment.

[0139] The image plane size is 5.5mm~6.5mm, which matches the sensor size of mainstream projectors, ensuring the compatibility of the projected image and the best imaging effect.

[0140] Table 1 shows the optical parameter design in one state (eg, initial state). It should be noted that the projection lens module provided in the embodiment of the present application includes but is not limited to the optical design in Table 1, and other aspects can be referred to in the following embodiments 1 to 3.

[0141] The optical performance of the projection lens module provided in the embodiment of the present application is as follows: See also Figure 3 , Figure 3 for Figure 1 The distortion diagram of the projection lens module shown in Table 1 has an absolute value of distortion less than 0.8%.

[0142] See also Figure 4 , Figure 4 for Figure 1 And the MTF diagram of the projection lens module shown in Table 1, its MTF is >0.5 at 93lp / mm.

[0143] See also Figure 5 , Figure 5 for Figure 1 The dot array diagram of the projection lens module shown in Table 1 has a maximum value of less than 5 μm for the image points in the dot array diagram.

[0144] See also Figure 6 , Figure 6 for Figure 1 The vertical axis chromatic aberration diagram of the projection lens module shown in FIG. 1 has a maximum chromatic aberration value of less than 1 μm.

[0145] According to another embodiment of the present application, a micro-projection device is provided. The micro-projection device includes a housing and the projection lens module as described above.

[0146] The micro-projection device provided in the embodiment of the present application can be applied to commercial micro-projection devices.

[0147] The specific implementation of the micro-projection device in the embodiment of the present application can refer to the various embodiments of the projection lens module described above, and therefore at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0148] The projection lens module of the present application is described below through Examples 1 to 3. Example 1 is a long focus mode of the projection lens module, Example 2 is a medium focus mode of the projection lens module, and Example 3 is a short focus mode of the projection lens module.

[0149] Example 1 See also Figure 7 The projection lens module provided in Example 1 includes a projection lens, a glass plate 13 and a display unit 12 arranged in sequence along the same optical axis; wherein the display unit 12 is used to provide light for projection imaging to the projection lens, and the projection lens is used to project the light emitted by the display unit 12 for imaging; The projection lens comprises a first lens group, a second lens group and an aperture 9 arranged along the same optical axis; The first lens group includes a first doublet lens and a third lens 3 arranged along the optical axis, wherein the first doublet lens has positive focal power, the first doublet lens is composed of a first lens 1 and a second lens 2 glued together, the first lens 1 has positive focal power, the second lens 2 has negative focal power, and the third lens 3 has negative focal power; The second lens group includes a second double-cemented lens, a third double-cemented lens and an eighth lens 8 which are sequentially arranged along the optical axis, wherein the second double-cemented lens, the third double-cemented lens and the eighth lens 8 all have positive focal power, wherein the second double-cemented lens includes a fourth lens 4 and a fifth lens 5 which are bonded to each other, wherein the fourth lens 4 has positive focal power, and the fifth lens 5 has negative focal power; the third double-cemented lens includes a sixth lens 6 and a seventh lens 7 which are bonded to each other, wherein the sixth lens 6 is a negative lens, and the seventh lens 7 is a positive lens; The first lens 1 to the eighth lens 8 in the projection lens are all glass spherical lenses; The aperture 9 is located between the third lens 3 and the fourth lens 4; The first double-cemented lens and the third double-cemented lens can be moved synchronously along the optical axis, and through the coordinated displacement of the two: The movement of the first doublet lens is used to adjust the focal length of the projection lens module; The movement of the third double cemented lens is used to compensate for the image plane displacement caused by the change of focal length; The projection lens module further includes a galvanometer mirror 10 and a prism 11 which are located on the object side of the eighth lens 8 and are sequentially arranged along the optical axis.

[0150] The projection lens module provided in this embodiment 1 is in telephoto mode.

[0151] See also Figure 7 , Figure 7 The optical parameters of the projection lens module shown are shown in Table 2 below.

[0152] Table 2

[0153] The optical performance of the projection lens module provided in this embodiment 1 is as follows: Figures 8 to 11 As shown: Figure 8 is a schematic diagram of the point diagram. Fig. 9 is the MTF curve graph, Fig.10 is the field curvature and distortion diagram, Fig.11 This is the vertical axis chromatic aberration diagram.

[0154] See also Figure 8 In the projection lens module provided in the first embodiment, the maximum value of the image point in the point diagram is less than 3 μm.

[0155] See also Fig. 9 The projection lens module provided in this embodiment 1 has an MTF of >0.35 at 125lp / mm.

[0156] See also Fig.10In the projection lens module provided in the present embodiment 1, the maximum distortion occurs in 1 field of view, and the absolute value is less than 0.15%.

[0157] See also Fig.11 The projection lens module provided in this embodiment 1 has a maximum chromatic aberration value of less than 1 μm.

[0158] Example 2 See also Fig.12 The projection lens module provided in Example 2 includes a projection lens, a glass plate 13 and a display unit 12 arranged in sequence along the same optical axis; wherein the display unit 12 is used to provide light for projection imaging to the projection lens, and the projection lens is used to project the light emitted by the display unit 12 for imaging; The projection lens comprises a first lens group, a second lens group and an aperture 9 arranged along the same optical axis; The first lens group includes a first doublet lens and a third lens 3 arranged along the optical axis, wherein the first doublet lens has positive focal power, the first doublet lens is composed of a first lens 1 and a second lens 2 glued together, the first lens 1 has positive focal power, the second lens 2 has negative focal power, and the third lens 3 has negative focal power; The second lens group includes a second double-cemented lens, a third double-cemented lens and an eighth lens 8 which are sequentially arranged along the optical axis, wherein the second double-cemented lens, the third double-cemented lens and the eighth lens 8 all have positive focal power, wherein the second double-cemented lens includes a fourth lens 4 and a fifth lens 5 which are bonded to each other, wherein the fourth lens 4 has positive focal power, and the fifth lens 5 has negative focal power; the third double-cemented lens includes a sixth lens 6 and a seventh lens 7 which are bonded to each other, wherein the sixth lens 6 is a negative lens, and the seventh lens 7 is a positive lens; The first lens 1 to the eighth lens 8 in the projection lens are all glass spherical lenses; The aperture 9 is located between the third lens 3 and the fourth lens 4; The first double-cemented lens and the third double-cemented lens can be moved synchronously along the optical axis, and through the coordinated displacement of the two: The movement of the first doublet lens is used to adjust the focal length of the projection lens module; The movement of the third double cemented lens is used to compensate for the image plane displacement caused by the change of focal length; The projection lens module further includes a galvanometer mirror 10 and a prism 11 which are located on the object side of the eighth lens 8 and are sequentially arranged along the optical axis.

[0159] The projection lens module provided in this embodiment 2 is in the mid-focus mode.

[0160] See also Fig.12 , Fig.12 The optical parameters of the projection lens module shown are shown in Table 3 below.

[0161] Table 3

[0162] The optical performance of the projection lens module provided in this embodiment 2 is as follows: Figures 13 to 16 As shown: Fig.13 is a schematic diagram of the point diagram. Fig.14 is the MTF curve graph, Fig.15 is the field curvature and distortion diagram, Fig.16 This is the vertical axis chromatic aberration diagram.

[0163] See also Fig.13 In the projection lens module provided in the second embodiment, the maximum value of the image point in the point diagram is less than 3 μm.

[0164] See also Fig.14 The projection lens module provided in this embodiment 2 has an MTF of >0.35 at 125lp / mm.

[0165] See also Fig.15 In the projection lens module provided in the second embodiment, the maximum distortion occurs in 1 field of view, and the absolute value is less than 0.3%.

[0166] See also Fig.16 The projection lens module provided in this embodiment 2 has a maximum chromatic aberration value of less than 2 μm.

[0167] Example 3 See also Fig.17 The projection lens module provided in Example 3 includes a projection lens, a glass plate 13 and a display unit 12 arranged in sequence along the same optical axis; wherein the display unit 12 is used to provide light for projection imaging to the projection lens, and the projection lens is used to project the light emitted by the display unit 12 for imaging; The projection lens comprises a first lens group, a second lens group and an aperture 9 arranged along the same optical axis; The first lens group includes a first doublet lens and a third lens 3 arranged along the optical axis, wherein the first doublet lens has positive focal power, the first doublet lens is composed of a first lens 1 and a second lens 2 glued together, the first lens 1 has positive focal power, the second lens 2 has negative focal power, and the third lens 3 has negative focal power; The second lens group includes a second double-cemented lens, a third double-cemented lens and an eighth lens 8 which are sequentially arranged along the optical axis, wherein the second double-cemented lens, the third double-cemented lens and the eighth lens 8 all have positive focal power, wherein the second double-cemented lens includes a fourth lens 4 and a fifth lens 5 which are bonded to each other, wherein the fourth lens 4 has positive focal power, and the fifth lens 5 has negative focal power; the third double-cemented lens includes a sixth lens 6 and a seventh lens 7 which are bonded to each other, wherein the sixth lens 6 is a negative lens, and the seventh lens 7 is a positive lens; The first lens 1 to the eighth lens 8 in the projection lens are all glass spherical lenses; The aperture 9 is located between the third lens 3 and the fourth lens 4; The first double-cemented lens and the third double-cemented lens can be moved synchronously along the optical axis, and through the coordinated displacement of the two: The movement of the first doublet lens is used to adjust the focal length of the projection lens module; The movement of the third double cemented lens is used to compensate for the image plane displacement caused by the change of focal length; The projection lens module further includes a galvanometer mirror 10 and a prism 11 which are located on the object side of the eighth lens 8 and are sequentially arranged along the optical axis.

[0168] The projection lens module provided in this embodiment 3 is in short-focus mode.

[0169] See also Fig.17 , Fig.17 The optical parameters of the projection lens module shown are shown in Table 4 below.

[0170] Table 4

[0171] The projection lens module provided in this embodiment 3 has an optical performance as follows: Figures 18 to 21 As shown: Fig.18 is a schematic diagram of the point diagram. Fig.19 is the MTF curve graph, Fig. 20 is the field curvature and distortion diagram, Fig.21 This is the vertical axis chromatic aberration diagram.

[0172] See also Fig.18 In the projection lens module provided in the third embodiment, the maximum value of the image point in the point diagram is less than 4 μm.

[0173] See also Fig.19 The projection lens module provided in this embodiment 3 has an MTF of >0.4 at 125lp / mm.

[0174] See also Fig. 20In the projection lens module provided in the third embodiment, the maximum distortion occurs in 1 field of view, and the absolute value is less than 0.7%.

[0175] See also Fig.21 The projection lens module provided in this embodiment 3 has a maximum chromatic aberration value of less than 3 μm.

[0176] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0177] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A projection lens module, characterized in that: The lens comprises a first lens group, an aperture (9) and a second lens group in sequence from the image side to the object side along the optical axis; The first lens group comprises a first doublet lens and a third lens (3) arranged along the optical axis, the first doublet lens having a positive optical power, and the third lens (3) having a negative optical power; The second lens group comprises a second double-cemented lens, a third double-cemented lens and an eighth lens (8) which are arranged in sequence along the optical axis, and the second double-cemented lens, the third double-cemented lens and the eighth lens (8) all have positive focal power; The aperture (9) is located between the third lens (3) and the second doublet lens; The first double-cemented lens and the third double-cemented lens can be moved synchronously along the optical axis, and through the coordinated displacement of the two: The movement of the first doublet lens is used to adjust the focal length of the projection lens module; The movement of the third double cemented lens is used to compensate for the image plane displacement caused by the change of focal length.

2. The projection lens module according to claim 1, characterized in that: The central thickness T3 of the third lens (3) and the total optical length TTL of the projection lens module satisfy the following relationship: 8%<T3 / TTL<11.5%.

3. The projection lens module according to claim 1 or 2, characterized in that: The sagittal height at the maximum aperture on the image side of the third lens (3) is S1, and the sagittal height at the maximum aperture on the object side is S2, and the ratio of S1 to S2 satisfies: 1.2<S1 / S2<1.

8.

4. The projection lens module according to claim 3, characterized in that: The angle between the tangent line at the maximum aperture of the object side of the third lens (3) and the optical axis is A1, and the angle between the tangent line at the maximum aperture of the image side and the optical axis is A2, and A1 and A2 satisfy: 42°<(A1+A2) / 2<49°, and 0.85<A1 / A2<1.

05.

5. The projection lens module according to claim 1, characterized in that: The sum T' of the center thicknesses of the first double-cemented lens, the second double-cemented lens, and the third double-cemented lens satisfies the following relationship with the total optical length TTL of the projection lens module: 16%<T' / TTL<33%.

6. The projection lens module according to claim 1 or 5, characterized in that: The central thickness T1 of the first double-cemented lens and the total optical length TTL of the projection lens module satisfy the following: 7%<T1' / TTL<14%.

7. The projection lens module according to claim 6, characterized in that: The first double-cemented lens is composed of a first lens (1) and a second lens (2) cemented together, wherein the first lens (1) has positive focal power, the second lens (2) has negative focal power, and the refractive index N1 of the first lens (1) is lower than the refractive index N2 of the second lens (2).

8. The projection lens module according to claim 7, characterized in that: The first lens group satisfies: 10<(T3+T1) / T2<14; wherein T1 is the center thickness of the first lens (1), T2 is the center thickness of the second lens (2), and T3 is the center thickness of the third lens (3).

9. The projection lens module according to claim 1 or 5, characterized in that: The second doublet lens is composed of a fourth lens (4) and a fifth lens (5) glued together, wherein the fourth lens (4) has a positive focal power, the fifth lens (5) has a negative focal power, and the refractive index N4 of the fourth lens (4) is lower than the refractive index N5 of the fifth lens (5); The third double-cemented lens is composed of a sixth lens (6) and a seventh lens (7) cemented together, wherein the sixth lens (6) has a negative optical focal length, the seventh lens (7) has a positive optical focal length, and the refractive index N7 of the seventh lens (7) is lower than the refractive index N6 of the sixth lens (6).

10. The projection lens module according to claim 9, characterized in that: The fourth lens (4), the fifth lens (5), the sixth lens (6) and the seventh lens (7) satisfy the following relationship: 3<(T4+T7) / (T5+T6)<4.8; wherein T4 is the center thickness of the fourth lens (4), T5 is the center thickness of the fifth lens (5), T6 is the center thickness of the sixth lens (6), and T7 is the center thickness of the seventh lens (7).

11. The projection lens module according to claim 1, characterized in that: The effective focal length of each lens in the projection lens module satisfies: The effective focal length of the first double cemented lens is F', 70mm≤F'≤90mm; The effective focal length of the third lens (3) is F3, -20mm≤F3≤-13mm; The effective focal length of the second double cemented lens is F'', 600mm≤F''≤800mm; The effective focal length of the third double-cemented lens is F''', 25mm≤F'''≤37mm; The effective focal length of the eighth lens (8) is F8, 52mm≤F8≤74mm; Each lens in the projection lens module is a glass spherical lens.

12. The projection lens module according to claim 1, characterized in that: The projection lens module further comprises a galvanometer (10), a prism (11), a glass plate (13) and a display unit (12) which are located on the object side of the eighth lens (8) and are arranged in sequence; The ratio of the total optical length TTL of the projection lens module to the maximum aperture D1 of the lens in the projection lens module satisfies: 1.7<TTL / D1<2.

7.

13. The projection lens module according to claim 12, characterized in that: The total optical length TTL of the projection lens module is 59mm<TTL<85mm, and the maximum effective aperture is 33mm.

14. The projection lens module according to claim 13, characterized in that: The optical parameters of the projection lens module include: focal length of 21mm~32mm, projection ratio TR of 4~6, relative aperture of 1 / 1.73, Offset: 0%, pixel size of 5.4μm, field of view angle of 5.2°~8.1°, image plane size of 5.5mm~6.5mm, and working band of 455nm~630nm.

15. A micro-projection device, characterized in that: include: shell; and A projection lens module as claimed in any one of claims 1 to 14.

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