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 image side to an object side along an optical axis. The first lens group comprises a first doublet lens, a third lens, a second doublet lens, a sixth lens and a seventh lens which are sequentially arranged along the optical axis, the first doublet lens, the third lens, the sixth lens and the seventh lens are all positive focal power, and the second doublet lens is negative focal power; the second lens group comprises an eighth lens, a ninth lens and a tenth lens which are sequentially arranged along the optical axis, the eighth lens is of negative focal power, and the ninth lens and the tenth lens are of positive focal power; the diaphragm is located between the seventh lens and the eighth lens. The third lens and the second doublet lens form a linkage zoom lens group and are configured to be capable of synchronously moving along the optical axis, and the distance between the third lens and the second doublet lens is kept constant, so that the projection lens module can realize zooming within a preset focal length range.

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 an important tool for commercial display and advertising, the optimization of the optical performance of commercial micro projectors has always been the focus of industry technology development. In projection optical design, the matching of focal length and field of view directly affects the size adjustment range and applicable scenarios of the projection image. At present, mainstream commercial micro projection equipment mostly adopts a fixed focal length projection lens design. Although this solution has a simple optical structure, it has obvious limitations: on the one hand, the fixed focal length makes it impossible to flexibly adjust the size of the projection image according to the actual application scenario; on the other hand, in order to meet the requirements of different projection distances, it is often necessary to equip multiple sets of lenses with different focal lengths, which increases the equipment cost and maintenance difficulty.

[0003] Although there are some zoom projection lens designs in the prior art, the following technical defects still exist: First, the total optical length of traditional zoom lenses changes significantly during the zooming process, resulting in large fluctuations in the optical and mechanical dimensions, which is prone to mechanical interference with other components inside the equipment; second, in order to achieve good image quality compensation, most solutions use aspherical lenses or complex lens group structures, which not only increases the manufacturing cost, but also puts higher requirements on the assembly process; in addition, the projection ratio range of existing zoom lenses is limited, which makes it difficult to meet the special needs of long-distance large-screen projection in commercial displays.

[0004] For example, in application scenarios such as ground projection in front of shops, it is necessary to maintain a compact body size (for concealed installation), and the projection lens must have a sufficient focal length adjustment range (to adapt to different store spacing), while also controlling costs. These mutually restrictive requirements make it difficult for existing projection lens solutions to achieve a technical balance. Therefore, developing a zoom projection lens with a large projection ratio, small size, and basically unchanged total optical length has become a technical problem that needs to be solved in this field. Summary of the invention

[0005] The purpose of this application is to provide a new technical solution for a projection lens module and a micro-projection device.

[0006] 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 an image side to an object side along an optical axis; The first lens group includes a first doublet lens, a third lens, a second doublet lens, a sixth lens, and a seventh lens arranged in sequence along the optical axis. Among them, the first doublet lens, the third lens, the sixth lens, and the seventh lens all have positive optical powers, and the second doublet lens has a negative optical power; The second lens group includes an eighth lens, a ninth lens, and a tenth lens arranged in sequence along the optical axis. Among them, the eighth lens has a negative optical power, and the ninth lens and the tenth lens both have positive optical powers; The aperture stop is located between the seventh lens and the eighth lens; Among them, the third lens and the second doublet lens form a linkage zoom lens group and are configured to be able to move synchronously along the optical axis, and the distance between them remains constant, so that the projection lens module can achieve zoom within a predetermined focal length range.

[0007] Optionally, the second doublet lens is composed of a fourth lens and a fifth lens glued together. Among them, the fourth lens has a negative optical power, the fifth lens has a positive optical power, and the refractive index N4 of the fourth lens is lower than the refractive index N5 of the fifth lens.

[0008] Optionally, the sagittal height at the maximum aperture of the object side of the third lens is S1, and the sagittal height at the maximum aperture of the image side is S2. The ratio of S1 to S2 satisfies: 1.3 < S2 / S1 < 2.4.

[0009] Optionally, the angle between the tangent line at the maximum aperture of the object side 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 and the optical axis is A2. A1 and A2 satisfy: 90° < (A1 + A2) / 2 < 110° and 0.93 < A1 / A2 < 1.08.

[0010] Optionally, the first doublet lens is composed of a first lens and a second lens glued together. Among them, the first lens has a negative optical power, the second lens has a positive optical power, and the refractive index N2 of the second lens is lower than the refractive index N1 of the first lens.

[0011] Optionally, the central thickness T' of the first doublet lens and the overall optical length TTL of the projection lens module satisfy: 5.5% < T' / TTL < 7.9%.

[0012] Optionally, in the first lens group, the central thickness T2 of the second lens, the central thickness T3 of the third lens, the central thickness T6 of the sixth lens, and the central thickness T7 of the seventh lens satisfy: 3 < (T2 + T7) / (T3 + T6) < 3.8.

[0013] Optionally, in the first lens group, the central thickness T7 of the seventh lens and the overall optical length TTL of the projection lens module satisfy: 5.62% < T7 / TTL < 8.12%.

[0014] Optionally, in the second lens group, the central thickness T9 of the ninth lens and the overall optical length TTL of the projection lens module satisfy: 6.3% < T9 / TTL < 8.8%.

[0015] Optionally, for the ninth lens, the angle between the tangent at the maximum aperture of the object side and the optical axis is A3, and the angle between the tangent at the maximum aperture of the image side and the optical axis is A4. A3 and A4 satisfy: 110° < (A3 + A4) / 2 < 130° and 0.75 < A3 / A4 < 1.26.

[0016] Optionally, the central thickness T8 of the eighth lens, the central thickness T9 of the ninth lens, and the central thickness T10 of the tenth lens satisfy: 6 < (T9 + T10) / T8 < 9.5.

[0017] Optionally, the effective focal lengths of the lenses in the projection lens module satisfy: The effective focal length of the first doublet lens is F', and 50 mm ≤ F' ≤ 72 mm; The effective focal length of the third lens is F3, and 140 mm ≤ F3 ≤ 170 mm; The effective focal length of the second doublet lens is F'', and -19 mm ≤ F'' ≤ -15 mm; The effective focal length of the sixth lens is, and 35 mm ≤ F6 ≤ 50 mm; The effective focal length of the seventh lens is, and 20 mm ≤ F7 ≤ 30 mm; The effective focal length of the eighth lens is F8, and -11 mm ≤ F8 ≤ -8 mm; The effective focal length of the ninth lens is F9, and 30 mm ≤ F9 ≤ 40 mm; The effective focal length of the tenth lens is F10, and 18 mm ≤ F10 ≤ 27 mm; All the lenses in the projection lens module are glass spherical lenses.

[0018] Optionally, the projection lens module further includes a galvanometer, a prism, a glass plate, and a display unit that are sequentially arranged on the object side of the tenth lens; The ratio of the overall optical length TTL of the projection lens module to the maximum aperture D1 of the lenses in the projection lens module satisfies: 2.9 < TTL / D1 < 3.7.

[0019] Optionally, the focal length of the projection lens module is 23.5 mm to 35.1 mm, the projection ratio TR is 4.5 to 6.7, the relative aperture is 1 / 1.7, the Offset is 0%, the pixel size is 5.4 μm, the field of view angle is 4.7° to 7.3°, the image plane size is 5.3 mm to 6.6 mm, and the working wavelength band is 455 nm to 630 nm.

[0020] In a second aspect, an embodiment of the present application provides a micro-projection device, which includes: a housing; and the projection lens module as described in the second aspect.

[0021] The beneficial effects of the present application are as follows: For the projection lens module provided by the embodiment of the present application, by synchronously moving the positions of the third lens and the second doublet along the optical axis, the adjustable function of the focal length of the entire module is realized. Particularly significantly, during the zooming process, the change rate of the overall optical length of the projection lens module is controlled within 3.3%, that is, the overall optical length remains basically unchanged. This design effectively solves the problems that traditional zoom lenses have large size changes and relatively complex optical structure designs during zooming. This characteristic makes the present application more suitable for micro-projection devices with limited space, realizing the combination of the zoom function and the compact structure design.

[0022] In the present application, a lens combination and configuration are specially designed. Only ten lenses can be used, including two doublets and six single lenses. Through the design of the optical power distribution of the lenses in the module, while reducing the number of lenses, not only a large projection ratio (such as 4.5 to 6.7) and a wide focal length range (such as 23.5 mm to 35.1 mm) are realized, but also the optical design difficulty is further reduced. This optical design of the present application ensures high definition and high contrast of the projection image, bringing an excellent visual experience to users.

[0023] It should be emphasized that during the zooming process, the overall optical length of the projection lens module provided by the present application remains basically unchanged, which greatly ensures the structural compactness and optical performance stability during the zooming process. At the same time, due to the overall optical design optimization of the module, the imaging quality consistency during the zooming process is also fully guaranteed, ensuring stable imaging effects at different focal lengths. Whether it is short-distance small-range projection or long-distance large-range projection, the present application can achieve clear imaging and meet diverse projection requirements.

[0024] Through the following detailed description of the exemplary embodiments of this specification with reference to the accompanying drawings, other features and advantages of this specification will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings incorporated in and forming a part of this specification illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0026] Figure 1 Schematic diagrams of the projection lens module provided by the embodiments of the present application in different focal length states; Figure 2 Partial structural schematic diagram of the third lens of the projection lens provided by the embodiments of the present application; Figure 3 Partial structural schematic diagram of the ninth lens of the projection lens provided by the embodiments of the present application Figure 4 Optical architecture schematic diagram of the projection lens module provided by the embodiments of the present application; Figure 5 For Figure 4 Distortion diagram of the projection lens module in Figure 6 For Figure 4 MTF diagram of the projection lens module in Figure 7 Structural and optical path diagram of the projection lens module (long focal length) provided by Embodiment 1 of the present application; Figure 8 For Figure 7 Dot array diagram of the projection lens module provided; Figure 9 For Figure 7 MTF diagram of the projection lens module provided; Figure 10 For Figure 7 Field curvature and distortion diagram of the projection lens module provided; Figure 11 For Figure 7 Lateral chromatic aberration diagram of the projection lens module provided; Figure 12 Structural and optical path diagram of the projection lens module (medium focal length) provided by Embodiment 2 of the present application; Figure 13 For Figure 12 Dot array diagram of the projection lens module provided; Figure 14 For Figure 12 MTF diagram of the projection lens module provided; Figure 15 For Figure 12 Field curvature and distortion diagram of the projection lens module provided; Figure 16 For Figure 12 Lateral chromatic aberration diagram of the projection lens module provided; Figure 17 Structural and optical path diagram of the projection lens module (short focal length) provided by Embodiment 3 of the present application; Figure 18 For Figure 17 the dot array diagram of the provided projection lens module; Figure 19 For Figure 17 the MTF diagram of the provided projection lens module; Figure 20 For Figure 17 the field curvature and distortion diagram of the provided projection lens module; Figure 21 For Figure 17 the lateral chromatic aberration diagram of the provided projection lens module; Figure 22 The figure shows the corresponding relationship between the focal length of the projection lens module provided in the embodiments of the present application and the air spacings A and B.

[0027] Explanation 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, ninth lens; 10, tenth lens; 11, aperture stop; 12, galvanometer; 13, prism; 14, display unit; 15, glass plate. Detailed implementation manners

[0028] 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 arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application.

[0029] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present application or its application or use.

[0030] Technologies and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies and devices should be regarded as part of the specification.

[0031] In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0032] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0033] The projection lens module and the micro-projection device provided in the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0034] According to an embodiment of the present application, a projection lens module is provided. Figure 1 and Figure 4 The projection lens module includes a first lens group, an aperture 11 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, a third lens 3, a second doublet lens, a sixth lens 6 and a seventh lens 7 arranged in sequence along the optical axis, wherein the first doublet lens, the third lens 3, the sixth lens 6 and the seventh lens 7 are all positive focal lengths, and the second doublet lens is negative focal lengths. The second lens group includes an eighth lens 8, a ninth lens 9 and a tenth lens 10 arranged in sequence along the optical axis, wherein the eighth lens 8 is negative focal length, and the ninth lens 9 and the tenth lens 10 are all positive focal lengths. The aperture 11 is located between the seventh lens 7 and the eighth lens 8. In the projection lens module, the third lens 3 and the second doublet lens constitute a linkage zoom lens group, and are configured so that the two can move synchronously along the optical axis, and the distance between the two is kept constant, so that the projection lens module can achieve zooming within a predetermined focal length range.

[0035] The projection lens module provided in the embodiment of the present application is shown in FIG. Figure 1 and Figure 4 , its main components include a projection lens and a display unit 14. The projection lens includes the above-mentioned first lens group, the second lens group and the diaphragm 11 located between the two lens groups (the position of the diaphragm 11 is fixed, that is, the distance between the diaphragm 11 and the lenses on both sides is fixed). The projection lens is located on the light output path of the display unit 14, and is responsible for receiving the light emitted from the display unit 14 (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 14 can be guided and projected onto the imaging surface, and finally present a clear projection picture.

[0036] Specifically, see Figure 1 and Figure 4 The projection lens module provided in the embodiment of the present application comprises a first lens group, a second lens group and an aperture 11; wherein the first lens group (in Figure 1 and Figure 4 The second lens group (positioned relatively to the left) is further away from the display unit 14 in the projection lens module than the second lens group; the second lens group (positioned relatively to the left) is further away from the display unit 14 in the projection lens module. Figure 1 and Figure 4 The aperture 11 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.

[0037] It should be noted that seeFigure 4 In the optical architecture provided by the application, the side where the display unit 14 is located is defined as the object side, and the side away from the display unit 14 is defined as the image side.

[0038] The first lens group provided in the embodiments of the present application is specifically described as follows.

[0039] The first lens group provided in the embodiments of the present application is one of the components of the projection lens module (or the projection lens). The first lens group is mainly composed of the first lens 1 to the seventh lens 7. See Figure 4 , the first lens 1 and the second lens 2 are mutually cemented to form a first doublet lens, the fourth lens 4 and the fifth lens 5 are mutually cemented to form a second doublet lens, and the third lens 3, the sixth lens 6 and the seventh lens 7 are all separately arranged. These seven lenses in the first lens group each play an important role in the entire projection lens module.

[0040] The power distribution method of each lens in the first lens group is as follows: the first doublet lens with positive power is located at the forefront (i.e., close to the image side, see the left side in Figure 4 ), followed by the third lens 3 with positive power, then the second doublet lens with negative power, and finally the sixth lens 6 and the seventh lens 7 with positive power in sequence. This positive-positive-negative-positive-positive power distribution in the first lens group can effectively balance aberrations such as spherical aberration, coma, and field curvature. Specifically: The first doublet lens (with positive power) and the third lens 3 (with positive power) located at the front end provide the main converging ability, but will introduce positive spherical aberration and positive field curvature. The subsequent second doublet lens (with negative power) can be used to offset the positive spherical aberration generated by the front group, and at the same time correct chromatic aberration (such as axial chromatic aberration) through the refractive index difference of the cemented surface. The sixth lens 6 (with positive power) and the seventh lens 7 (with positive power) at the rear end can be used to further optimize the flatness of the image plane and cooperate with the position of the aperture 11 to control astigmatism.

[0041] The power distribution method in the first lens group provides a good optical basis for the synchronous movement of positive and negative lenses (i.e., the zoom process), ensuring stable imaging quality during the zoom process. That is to say, it enables the projection lens module to maintain good imaging characteristics at different focal lengths and meet the requirements of different projection scenarios.

[0042] While maintaining high performance, the power distribution method of the first lens group also helps to achieve the miniaturized design of the entire projection lens module, so as to adapt to the needs of micro-projection devices.

[0043] In the first lens group, the third lens 3 and the second doublet lens form a linkage zoom lens group, which is designed to be movable along the optical axis between the first doublet lens and the sixth lens 6 to change the air gap A between the linkage zoom lens group and the first doublet lens, and the air gap B between the linkage zoom lens group and the sixth lens 6. Refer to Figure 7 , Figure 12 and Figure 17 . This is the key to realizing the zoom of the projection lens module in this application. It should be noted that during the zoom process, the distance between the third lens 3 and the second doublet lens remains unchanged.

[0044] The second lens group provided in the embodiment of the present application, refer to Figure 1 and Figure 4 . It is another component of the projection lens module. The second lens group mainly consists of an eighth lens 8, a ninth lens 9 and a tenth lens 10. In the lens arrangement of the second lens group, the eighth lens 8 with negative optical power is close to the aperture stop 11, followed by the ninth lens 9 and the tenth lens 10 with positive optical power in sequence. This negative-positive-positive optical power configuration helps to further correct aberrations.

[0045] Specifically, the eighth lens 8 (with negative optical power) is located behind the aperture stop 11. Its main function is to offset the spherical aberration and field curvature remaining in the front group (such as the first lens group). Its diverging effect as a negative lens can flatten the image plane curvature caused by the strong positive optical power of the first lens group. Cooperating with the aperture stop (fixed between the two lens groups), it can control the chief ray angle and reduce astigmatism and coma. The ninth lens 9 (with positive optical power) and the tenth lens 10 (with positive optical power) are the converging main bodies of the rear group (the second lens group), mainly responsible for converging the light rays back to the imaging plane, compensating for the excessive divergence of the eighth lens 8, and ensuring that the total optical power of the projection lens module is positive. The optical power configuration (negative-positive-positive) of the second lens group and the optical power configuration (front group) of the first lens group work together to achieve high-performance optical performance.

[0046] During the zoom process, the optical total length change rate η of the projection lens module is controlled within 3.3%, that is, η = (TTL max -TTL min ) / TTL 0 ≤ 3.3%. This indicates that during the zoom process, the physical size of the projection lens module changes very little and is basically kept unchanged.

[0047] The projection lens module provided in the embodiment of the present application is significantly characterized in that it can realize the zoom function, and during the zoom process, the optical total length of the projection lens module at different focal lengths can be basically kept consistent. Refer to Figure 1, in the three working modes of short focus, medium focus, and long focus, the length of the projection lens module provided by the embodiments of the present application along the optical axis (i.e., the total optical length) remains basically the same. This advantage reflects the effect of controlling the change rate of the total optical length, that is, regardless of how the focal length changes, the overall size of the projection lens module (along the optical axis) can remain relatively stable.

[0048] In the design of the projection lens module provided by the embodiments of the present application, simultaneously moving the third lens 3 (positive optical power) and the second doublet lens (negative optical power) can achieve the zoom function and the total optical length remains basically unchanged. Its principle can be analyzed from the perspectives of optical path regulation and optical power compensation, and the specific analysis is as follows.

[0049] Regarding the movement of the third lens 3: The third lens 3 has a positive optical power. As a strong converging optical element in the first lens group, its movement will directly change the focal length of the projection lens module. For example, see Figure 17 , when the third lens 3 moves towards the image side, the air gap A between the third lens 3 and the first doublet lens decreases, and the focal length of the entire projection lens module shortens. Another example, see Figure 12 , when the third lens 3 moves towards the object side, the air gap A between the third lens 3 and the first doublet lens increases, and the focal length of the entire projection lens module increases.

[0050] Regarding the movement of the second doublet lens: The second doublet lens moves synchronously with the third lens 3, and the movement of the second doublet lens will change the air gap B between it and the sixth lens 6. The movement of the second doublet lens with negative optical power along the optical axis can offset the image plane displacement caused by the change in focal length. For example, see Figure 17 , when the third lens 3 moves towards the image side, the second doublet lens will move synchronously and compensate for the image plane displacement through the diverging effect.

[0051] In short, in the projection lens module provided by the embodiments of the present application, the coordinated movement of positive and negative lenses forms an "optical compensation zoom" mechanism. Through the mutual cancellation of optical powers, the position of the imaging plane is kept stable, thus avoiding the change in the total length.

[0052] It can be seen that for the projection lens module provided by the embodiments of the present application, during the zooming process, although the focal length is changing, the total optical length of the projection lens module can remain relatively stable.

[0053] When a traditional zoom lens zooms, due to the change in focal length, its physical size will change significantly, which may lead to an overly large overall size of the module (or the optical engine), not only increasing the volume and weight of the projection device, but also potentially limiting its application in scenarios with limited space. The projection lens module designed in this application effectively avoids this problem by controlling the change rate of the overall optical length.

[0054] In a projection device, other key components such as a light source and a heat dissipation system are often arranged around the projection lens module. The change in size of a traditional zoom lens during zooming may cause collisions or interference with these components, affecting the normal operation of the projection device. The optical design of this application effectively prevents such problems from occurring by maintaining the size stability of the projection lens module during the zooming process, improving the reliability and stability of the device.

[0055] In this application, the third lens 3 and the second doublet lens, as the core components of the zoom mechanism, change the distribution ratio of the optical power in the entire projection lens module by adjusting their positions in the optical path. This change directly affects the convergence path and focal length of the light rays, thereby achieving a focal length adjustment range from 23.5 mm to 35.1 mm. That is, by adjusting the positions of the third lens 3 and the second doublet lens on the optical axis, it is possible to flexibly adapt to different projection distances and screen size requirements. The cooperation of the first lens group and the second lens group enables the entire projection lens module to maintain high performance and stability during the zooming process. Whether in the telephoto, medium focal length, or wide-angle state, a high-quality projection image can be obtained, meeting the requirements of different projection distances and projection sizes.

[0056] See Figure 1 and Figure 4 , in the projection lens module, the aperture stop 11 is specifically located between the seventh lens 7 and the eighth lens 8, which is used to limit the passing range of light rays and control the size of the imaging light beam, thereby improving the imaging quality.

[0057] The projection lens module provided by the embodiments of this application can support zoom functions from telephoto, medium focal length to wide-angle, with a focal length adjustment range covering 23.5 mm to 35.1 mm and a projection ratio reaching 4.5 to 6.7, providing users with great flexibility and convenience.

[0058] The projection lens module provided by the embodiments of this application has lens length stability. See Figure 1, in three different working modes of long - focus, medium - focus, and short - focus, the overall optical length of the projection lens module remains basically the same. This design advantage significantly reduces the size change of the module (optical engine) caused by zooming, effectively avoiding the risk of collision or interference between the projection lens module and other device components during the zooming process. This kind of stability not only improves the overall reliability of the projection device, but also simplifies the mechanical structure design of the device and reduces the manufacturing cost.

[0059] In one example, referring to Figure 7 , when the projection lens module is in the long - focus state, at this time, the third lens 3 and the second doublet lens (composed of the fourth lens 4 and the fifth lens 5 glued together) will move closer to the sixth lens 6 along the optical axis direction. From Figure 7 , it can be observed that the air gap A between the third lens 3 and the first doublet lens is relatively large, while the air gap B between the second doublet lens and the sixth lens 6 is relatively small.

[0060] Conversely, referring to Figure 17 , when the projection lens module is in the short - focus state, the third lens 3 and the second doublet lens will move closer to the first doublet lens along the optical axis direction. At this time, the air gap A significantly decreases, while the air gap B significantly increases.

[0061] Referring to Figure 22 and Table 1, it intuitively shows the dynamic relationship between the air gap A, the air gap B, and the focal length of the projection lens module. From Figure 22 , it can be seen that as the air gap A decreases and the air gap B increases, the focal length of the projection lens module will correspondingly decrease, achieving the short - focus imaging effect; on the contrary, when the air gap A increases and the air gap B decreases, the focal length of the projection lens module will increase accordingly, reaching the long - focus state. This air - gap adjustment mechanism ensures that the projection lens module can maintain excellent imaging performance at different focal lengths.

[0062] Table 1 shows the corresponding relationship between the air gap A, the air gap B, and the focal length of the projection lens module.

[0063] Table 1

[0064] In some examples of this application, referring to Figure 4 , the second doublet lens is composed of the fourth lens 4 and the fifth lens 5 glued together. Among them, the fourth lens 4 has a negative optical power, the fifth lens 5 has a positive optical power, and the refractive index N4 of the fourth lens 4 is lower than the refractive index N5 of the fifth lens 5.

[0065] In the example provided by this application, the second doublet lens is composed of a fourth lens 4 with a negative optical power and a fifth lens 5 with a positive optical power, which are cemented together. Among them, the fourth lens 4 is a negative lens and has the characteristic of diverging light. The fifth lens 5 is a positive lens and has the characteristic of converging light. Gluing these two lenses with opposite optical powers together can correct the chromatic aberration introduced by a single lens, thereby improving the color reproducibility and clarity of the projected image. At the same time, since the refractive index N4 of the fourth lens 4 (negative lens) is designed to be lower than the refractive index N5 of the fifth lens 5 (positive lens), this refractive index difference helps to reduce aberrations such as spherical aberration and coma, and improves the imaging quality.

[0066] In this example provided by this application, the second doublet lens can effectively correct chromatic aberration and aberrations, and maintain stable optical performance at different focal lengths. Therefore, the entire projection lens module can provide high-quality projection effects under different working environments and usage conditions.

[0067] In one example, the refractive index N4 of the fourth lens 4 (negative lens) of the second doublet lens ranges from 1.55 to 1.73, and the refractive index N5 of the fifth lens 5 (positive lens) ranges from 1.78 to 1.83. In this second doublet lens, the positive lens with a higher refractive index, that is, the fifth lens 5, can converge light more effectively and improve the utilization rate of light. While the negative lens with a relatively lower refractive index, that is, the fourth lens 4, can diverge light more evenly, reducing the loss and distortion of light during propagation. In addition, the selection of the refractive indices of the positive and negative lenses will not excessively increase the production cost.

[0068] In some examples of this application, see Figure 4 , the sagittal height at the maximum aperture of the object side of the third lens 3 is S1, and the sagittal height at the maximum aperture of the image side is S2. The ratio of S1 to S2 satisfies: 1.3 < S2 / S1 < 2.4.

[0069] In the example provided by this application, the surface shape of the third lens 3 is regulated, and the proportional relationship between the sagittal height S1 at the maximum aperture of the object side and the sagittal height S2 at the maximum aperture of the image side of the third lens 3 is specifically described, that is, 1.3 < S2 / S1 < 2.4. In the projection lens module provided by the embodiment of this application, the third lens 3 is designed with a positive optical power and has the ability to converge light. By further controlling the ratio range of the above-mentioned S2 to S1, the following technical effects can be achieved.

[0070] (1) Optimization of aberration correction: The sagittal height of the two surfaces of the lens is an important parameter for describing the lens surface shape and has a direct impact on the aberration correction of the optical system. In this application, by adjusting the ratio range of S2 to S1, the converging ability of the third lens 3 to light can be optimized, thereby being able to correct aberrations, such as spherical aberration, chromatic aberration, etc., more effectively.

[0071] For the third lens 3 with positive optical power, a larger value of S2 / S1 means that the curvature radius of the image side is relatively large, which helps to reduce the refraction angle of the incident light and reduce the possibility of aberration generation.

[0072] (2)Improvement of optical performance: By controlling the ratio of S2 to S1 as described above, the optical performance of the third lens 3 can be optimized, including key optical parameters such as focal length. This helps to improve the optical performance of the entire projection lens module, making the projection image clearer and finer. In addition, the optimized sagittal height ratio also helps to achieve a more uniform spot distribution and improve the contrast and brightness uniformity of the projection image.

[0073] (3)Maintaining the structural compactness of the projection lens module: By controlling the sagittal height ratio of the image side to the object side of the third lens 3, a compact design of the projection lens module can be achieved without sacrificing optical performance. The optimized sagittal height ratio helps to reduce unnecessary space occupation, making the projection lens module smaller and lighter.

[0074] In some examples of this application, referring to 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: 90° < (A1 + A2) / 2 < 110° and 0.93 < A1 / A2 < 1.08.

[0075] In the examples provided in this application, the surface shape design of the third lens 3 is further controlled. The relationship between the angle A1 between the tangent line at the maximum aperture of the image and object sides of the third lens 3 and the optical axis, and the angle A2 between the tangent line at the maximum aperture of the object and image sides and the optical axis is specifically described. These two angles satisfy specific conditions, that is, 90° < (A1 + A2) / 2 < 110° and 0.93 < A1 / A2 < 1.08. This design aims to optimize the optical performance of the projection lens module.

[0076] In this example provided in this application, by controlling the ratio of A1 to A2 and their sum, the refraction path of the third lens 3 to light can be optimized, thereby correcting aberrations, such as spherical aberration, coma aberration, etc., more effectively.

[0077] In particular, when (A1 + A2) / 2 is between 90° and 110°, it helps to balance the refraction and reflection of light on the surface of the third lens 3, reducing the generation of aberration. At the same time, controlling the ratio of A1 / A2 between 0.93 and 1.08 can ensure that the light refraction angles on the image side and the object side are neither too large nor too small, thereby further improving the aberration correction effect.

[0078] By controlling the relationship between A1 and A2, the optical performance of the third lens 3 can be optimized, such as key optical parameters like focal length and magnification. This helps to improve the optical performance of the entire projection lens module, making the projected image clearer and more delicate. In addition, by controlling the relationship between A1 and A2, a compact design of the projection lens module can be achieved without sacrificing optical performance.

[0079] In some examples of this application, referring to Figure 4 , the first doublet lens is composed of a first lens 1 and a second lens 2 glued together. Among them, the first lens 1 has a negative optical power, the second lens 2 has a positive optical power, and the refractive index N2 of the second lens 2 is lower than the refractive index N1 of the first lens 1.

[0080] In the examples provided in this application, the first lens 1 is a negative lens, which has the characteristic of diverging light; the second lens 2 is a positive lens, which has the characteristic of converging light. And, the refractive index N2 of the second lens 2 (positive lens) is lower than the refractive index N1 of the first lens 1 (negative lens). This combination of refractive index differences helps to optimize the optical performance of this first doublet lens.

[0081] In this example provided in this application, by gluing the first lens 1 with negative optical power and the second lens 2 with positive optical power, the aberration introduced by a single lens, such as spherical aberration and chromatic aberration, can be corrected. This aberration correction is crucial for improving the clarity and contrast of the projected image.

[0082] The first lens 1 with negative optical power diverges light, while the second lens 2 with positive optical power converges light. By gluing these two lenses and adjusting optical parameters such as refractive index, the propagation path and convergence point of light can be controlled, thereby achieving the required projection effect.

[0083] Since the refractive index N2 of the second lens 2 (positive lens) is lower than the refractive index N1 of the first lens 1 (negative lens), that is, the optical power of the positive lens is lower than that of the negative lens. This design can further optimize the optical performance of the formed first doublet lens. For example, it can reduce chromatic aberration, improve light transmittance, etc., thereby enhancing the optical performance of the entire projection lens module.

[0084] In the projection lens module provided by the embodiments of the present application, using a first doublet lens instead of multiple single lenses can make the projection lens module more compact while maintaining optical performance. This is of great significance for integration into miniaturized projection devices.

[0085] Since the first doublet lens is carefully designed to effectively correct chromatic aberration and various aberrations, the projection lens module can exhibit more stable and consistent imaging quality under different working environments and usage conditions. This characteristic is crucial for commercial micro projectors because it needs to continuously provide high-quality projection effects under various complex and changeable environmental conditions to meet the needs of different users and application scenarios. By optimizing the optical performance of the first doublet lens, the projection lens module provided by the present application ensures that clear, sharp, and color-accurate projection images can be output under different focal lengths and light conditions.

[0086] In one example, the refractive index N1 of the first lens 1 (negative lens) of the first doublet lens ranges from 1.78 to 1.83, and the refractive index N2 of the second lens 2 (positive lens) ranges from 1.55 to 1.73.

[0087] Among them, designing the refractive index N1 of the negative lens to be 1.78 to 1.83 (high refractive index) helps to better disperse short-wavelength light, while designing the refractive index N2 of the positive lens to be 1.55 to 1.73 (low refractive index) has a stronger converging effect on long-wavelength light. This refractive index combination can effectively correct chromatic aberration, thereby improving the color accuracy of the projection image. The high refractive index of the negative lens enables its surface curvature to be designed smaller, which helps to reduce aberrations such as spherical aberration and coma; at the same time, the low refractive index of the positive lens combined with an appropriate curvature can further correct these aberrations and improve the imaging quality. The high-refractive-index negative lens can effectively diverge light, while the low-refractive-index positive lens can converge light more gently. This combination enables the first doublet lens to maintain good light control ability at different focal lengths, ensuring the brightness and contrast of the projection screen. In addition, by using a high-refractive-index material to make the negative lens, the thickness and volume of the lens can be reduced while maintaining the same optical performance, which helps to achieve a more compact design of the projection lens module.

[0088] It should be noted that as a key component of the projection lens module, the performance of the first doublet lens directly affects the imaging quality of the entire projection lens module. By controlling the refractive index ranges of the first lens 1 and the second lens 2, it can be ensured that the first doublet lens can provide excellent optical performance at different focal lengths, thereby supporting the entire projection lens module to achieve high-quality projection effects.

[0089] In the projection lens module provided by the embodiments of the present application, two groups of doublet lenses are adopted: namely, the first doublet lens and the second doublet lens. The first doublet lens and the second doublet lens can effectively correct chromatic aberration through the combination of negative lenses and positive lenses inside them. Moreover, due to the difference in material refractive indices, the negative lenses and positive lenses inside each doublet lens have different diverging and converging effects on light of different wavelengths, thus acting together on the entire projection lens module, greatly reducing chromatic aberration and improving the color accuracy of the projected image.

[0090] In some examples of the present application, the central thickness T' of the first doublet lens and the optical total length TTL of the projection lens module satisfy: 5.5% < T' / TTL < 7.9%.

[0091] As one of the components of the projection lens module, the control of the central thickness T' of the first doublet lens has an important impact on the aberration correction, chromatic aberration compensation, light focusing ability, and compactness of the entire projection lens module.

[0092] Specifically, by controlling the ratio of T' to TTL within the above range, it can ensure that light is well modulated when passing through the first doublet lens, thereby optimizing the optical performance of the projection lens module. This design helps to improve the clarity and contrast of the projected image, making the projection effect more delicate and real. Moreover, by controlling the ratio of the central thickness T' of the first doublet lens to TTL within the above range, a compact design of the projection lens module can be achieved without sacrificing optical performance.

[0093] The design of the T' / TTL ratio in this example of the present application also helps to reduce the manufacturing cost of the entire module. On the one hand, a thicker doublet lens may require more advanced materials and manufacturing processes, but by optimizing the design parameters, the material cost can be reduced while ensuring performance. On the other hand, the compact structure design helps to reduce the number and complexity of lenses, thereby reducing the processing and assembly costs. In some examples of the present application, in the first lens group, the central thicknesses T2 of the second lens 2, T3 of the third lens 3, T6 of the sixth lens 6, and T7 of the seventh lens 7 satisfy: 3 < (T2 + T7) / (T3 + T6) < 3.8.

[0094] In the example provided by this application, the control of the central thickness of the four lenses included in the first lens group is described. Specifically, in the first lens group, the second lens 2 and the seventh lens 7 are two lenses with relatively large central thicknesses, which can be called thick lenses. The third lens 3 and the sixth lens 6 are two lenses with relatively small central thicknesses, which can be called thin lenses. In the design of this example of this application, the sum of the central thickness T2 of the second lens 2 and the central thickness T7 of the seventh lens 7 (T2 + T7) and the sum of the central thickness T3 of the third lens 3 and the central thickness T6 of the sixth lens 6 (T3 + T6) satisfy a specific proportional relationship, that is, 3 < (T2 + T7) / (T3 + T6) < 3.8. This design aims to optimize the optical performance of the projection lens module by controlling the proportional relationship of the central thicknesses of different lens groups.

[0095] In this example provided by this application, in the first lens group, by controlling the ratio of the sum of the central thicknesses of the two thicker lenses (T2 + T7) to the sum of the central thicknesses of the two thinner lenses (T3 + T6), the aberration in the projection lens module can be effectively corrected. For example, thicker lenses usually have a larger optical path difference, which helps to better control the propagation path of light, while thinner lenses can provide the necessary light adjustment function without increasing the complexity of the projection lens module. This proportional control also helps to achieve a more uniform spot distribution, improve the clarity and contrast of the projected image, and thus enhance the visual experience.

[0096] According to this example provided by this application, the structural compact design of the projection lens module can be achieved without sacrificing optical performance. By matching thicker lenses and thinner lenses, unnecessary space occupation can be reduced while ensuring sufficient optical performance, making the volume of the entire projection lens module smaller and more compact.

[0097] In some examples of this application, see Figure 4 , in the first lens group, the seventh lens 7 is a thick lens, and the central thickness T7 of the seventh lens 7 and the optical total length TTL of the projection lens module satisfy: 5.62% < T7 / TTL < 8.12%.

[0098] In the example provided by this application, the seventh lens 7 is designed as a thick lens, and a specific proportional relationship is satisfied between its central thickness T7 and the optical total length TTL of the entire projection lens module, that is, 5.62% < T7 / TTL < 8.12%. The design of this optical parameter is based on a comprehensive consideration of the optical performance, manufacturing process, and cost control of the projection lens module.

[0099] The seventh lens 7, as a thick lens with a relatively large thickness in the first lens group, the control of its central thickness T7 has a significant impact on the imaging quality of the projection lens module. By controlling the ratio of T7 to TTL within a reasonable range, it can ensure that light is well modulated when passing through the seventh lens 7, thereby optimizing the optical performance of the entire projection lens module.

[0100] The thick lens design helps to increase the effective optical path of the lens, which is particularly effective for correcting higher-order aberrations (such as spherical aberration, chromatic aberration, etc.). By reasonably controlling the value of T7 / TTL, the imaging quality of the projection lens module can be further improved without increasing the number of lenses.

[0101] While maintaining the optical performance, controlling the central thickness T7 of the seventh lens 7 within a certain range helps to achieve a compact design of the projection lens module (one thick lens can replace multiple lenses). The thick lens design helps to reduce the number of lenses used, thereby reducing material costs and assembly costs. This is of great significance for mass production and cost control.

[0102] In addition, the relatively thick seventh lens 7 has better mechanical strength and thermal stability, and can resist the influence of external environmental changes (such as temperature fluctuations, vibrations, etc.) on the performance of the projection lens module.

[0103] In summary, in this example of the present application, the seventh lens 7 is designed as a thick lens, and by controlling the ratio of its central thickness T7 to the overall optical length TTL of the projection lens module, multiple technical effects such as optimization of optical performance, improvement of module structure compactness, control of manufacturing process and cost, and enhancement of module stability and reliability are achieved. These effects act together on the entire projection lens module, improving its overall performance.

[0104] In some examples of the present application, refer to Figure 4 , in the second lens group, the ninth lens 9 is a thick lens, and the central thickness T9 of the ninth lens 9 and the overall optical length TTL of the projection lens module satisfy: 6.3% < T9 / TTL < 8.8%.

[0105] In the example provided by the present application, the ninth lens 9 in the second lens group is designed as a thick lens, and there is a specific proportional relationship between its central thickness T9 and the overall optical length TTL of the projection lens module, that is, 6.3% < T9 / TTL < 8.8%. This design of optical parameters is based on a comprehensive consideration of the performance, structure compactness, and manufacturing feasibility of the projection lens module.

[0106] The ninth lens 9, being a thick lens in the second lens group, the control of its central thickness T9 has an important impact on the optical imaging performance of the projection lens module. By controlling the ratio of T9 to TTL within a reasonable range, it can ensure that light is well modulated when passing through the ninth lens 9, thereby optimizing the optical performance of the entire projection lens module.

[0107] The thick lens design helps to increase the effective optical path of the lens, which is particularly effective in improving the imaging quality of the projection lens module. By further controlling the ratio of T9 / TTL, it is possible to further improve the imaging quality of the projection lens module without increasing the number of lenses.

[0108] By designing the ninth lens 9 as a thick lens and precisely controlling the ratio of its central thickness T9 to TTL, it is possible to achieve a compact design of the projection lens module without sacrificing optical performance. This compact design helps to reduce the overall size and weight of the projector.

[0109] In addition, the thickness design of the ninth lens 9 can not only improve the optical performance but also enhance the stability of the projection lens module. Thicker lenses usually have better thermal stability and mechanical strength, and can resist the influence of external environmental changes (such as temperature fluctuations, vibrations, etc.) on the module performance.

[0110] In some examples of this application, the angle between the tangent line at the maximum aperture of the object side of the ninth lens 9 and the optical axis is A3, and the angle between the tangent line at the maximum aperture of the image side and the optical axis is A4. A3 and A4 satisfy: 110° < (A3 + A4) / 2 < 130° and 0.75 < A3 / A4 < 1.26.

[0111] In the examples provided in this application, the surface shape of the ninth lens 9 is further controlled. Specifically, the relationship between the angle A3 between the tangent line at the maximum aperture of the object side of the ninth lens 9 and the optical axis, and the angle A4 between the tangent line at the maximum aperture of the image side and the optical axis is described, and these two angles need to satisfy specific conditions, that is, 110° < (A3 + A4) / 2 < 130° and 0.75 < A3 / A4 < 1.26. This design aims to optimize the optical performance of the projection lens module.

[0112] In the examples provided in this application, by controlling (A3 + A4) / 2 between 110° and 130°, the light refraction angles on the object side and the image side of the ninth lens 9 can be balanced, reducing the generation of aberrations such as spherical aberration and coma. At the same time, the ratio of A3 / A4 is controlled between 0.75 and 1.26, ensuring that the refraction path of light on the surface of the ninth lens 9 is more reasonable, and further improving the aberration correction effect.

[0113] The control parameters of the ninth lens 9 provided in this example of the present application can optimize its optical performance, which helps to improve the optical performance of the projection lens module, making the projected image clearer and more delicate. Moreover, by reasonably controlling the above parameters of the ninth lens 9, a compact structural design of the projection lens module can be achieved without sacrificing optical performance.

[0114] In some examples of the present application, referring to Figure 4 , the center thickness T8 of the eighth lens 8, the center thickness T9 of the ninth lens 9, and the center thickness T10 of the tenth lens 10 satisfy: 6 < (T9 + T10) / T8 < 9.5.

[0115] In the examples provided by the present application, the control of the center thickness ratio of lenses with different thicknesses in the second lens group is described. Specifically, in the second lens group, the ninth lens 9 and the tenth lens 10 are the two relatively thick lenses in the second lens group, while the eighth lens 8 is the relatively thin lens in the second lens group. On this basis, it is designed that the center thickness T8 of the eighth lens 8, the center thickness T9 of the ninth lens 9, and the center thickness T10 of the tenth lens 10 satisfy a specific proportional relationship, that is, 6 < (T9 + T10) / T8 < 9.5. That is to say, the sum of the center thicknesses of the two thick lenses in the second lens group and the sum of the center thicknesses of a thin lens satisfy the above mathematical relationship. This design aims to optimize the optical performance, structural compactness, and manufacturing cost of the projection lens module by controlling the thickness ratio of different lenses.

[0116] In the second lens group, the relatively thick lenses, namely the ninth lens 9 and the tenth lens 10, have a larger optical path difference, which helps to better control the refraction and convergence of light, thereby correcting the aberration in the projection lens module. The relatively thin lens, namely the eighth lens 8, can provide the necessary light adjustment function without increasing the complexity of the projection lens module.

[0117] According to this example of the present application, a compact design of the projection lens module can be achieved without sacrificing optical performance. Moreover, the cooperation of relatively thick lenses and relatively thin lenses can reduce unnecessary space occupation while ensuring sufficient optical performance, making the entire projection lens module smaller and lighter.

[0118] In addition, the relatively thick ninth lens 9 and tenth lens 10 have better mechanical strength and thermal stability, and can better resist the influence of external environmental changes (such as temperature fluctuations, vibrations, etc.) on the system performance. By finely controlling the thickness ratio of different lenses, the stress concentration and deformation between the lenses can be reduced, and the long-term use stability and lifespan of the projection lens module can be improved.

[0119] In some examples of the present application, referring toFigure 4 , the effective focal lengths of the lenses in the projection lens module satisfy: The effective focal length of the first doublet lens is F', where 50 mm ≤ F' ≤ 72 mm; The effective focal length of the third lens 3 is F3, where 140 mm ≤ F3 ≤ 170 m; The effective focal length of the second doublet lens is F'', where -19 mm ≤ F'' ≤ -15 mm; The effective focal length of the sixth lens 6 is, where 35 mm ≤ F6 ≤ 50 mm; The effective focal length of the seventh lens 7 is, where 20 mm ≤ F7 ≤ 30 mm; The effective focal length of the eighth lens 8 is F8, where -11 mm ≤ F8 ≤ -8 mm; The effective focal length of the ninth lens 9 is F9, where 30 mm ≤ F9 ≤ 40 mm; The effective focal length of the tenth lens 10 is F10, where 18 mm ≤ F10 ≤ 27 mm.

[0120] In this example of the present application, the control of the effective focal lengths of the lenses aims to achieve the best imaging effect of the entire projection lens module by optimizing the optical performance of each lens. By reasonably controlling the effective focal lengths of the lenses, the aberration in the projection lens module can be corrected more effectively. This optimization of aberration correction is crucial for improving the clarity and contrast of the projected image.

[0121] In this example provided by the present application, the range of the effective focal length F3 of the third lens 3 is from 140 mm to 170 mm, which is a relatively large focal length range. In a zoom projection lens module, the third lens 3 with a relatively large focal length range plays a key role in realizing the zoom function of the module. As a positive focal length lens, the flexible adjustment of the focal length of the third lens 3 helps the projection lens module to smoothly transition between long focus, medium focus, and short focus.

[0122] In this example provided by the present application, the range of the effective focal length F'' of the second doublet lens is from -19 mm to -15 mm, which is a range of negative focal power. The doublet lens with negative focal power can be used to correct chromatic aberration, balance light, and achieve precise adjustment of the focal length by cooperating with the third lens 3 with positive focal power (the two can move synchronously along the optical axis) during the zoom process of the module. That is, the second doublet lens, as a negative focal power element, cooperates with the positive focal power of the third lens 3 to jointly realize the zoom function of the projection lens module.

[0123] By precisely controlling the focal length ranges of the third lens 3 and the second doublet lens, the optical performance of the entire projection lens module at different focal lengths can be optimized. For example, the combination of a relatively large positive focal power (such as the third lens) and an appropriate negative focal power (such as the second doublet lens) helps to correct various aberrations and improve the clarity and contrast of the image. In addition, this focal length design also helps to miniaturize and lighten the lens module while maintaining excellent optical performance.

[0124] During the zooming process, the third lens 3 and the second doublet lens should move synchronously along the optical axis and maintain a constant relative spacing between them. This design mechanism requires that the focal length ranges of the lenses must be precisely matched to ensure the smoothness of the zooming process and the consistency of the imaging quality.

[0125] The focal length design of the third lens 3 and the second doublet lens also takes into account the overall structural compactness of the projection lens module. By reasonably setting the focal length ranges of these two lenses, a wider focal length coverage can be achieved without increasing the volume of the lens, thus meeting the requirements of micro-projection devices for space limitations.

[0126] In addition, by carefully designing the effective focal length ranges of other lenses, the projection lens module of the present application has achieved remarkable technical effects in terms of chromatic aberration correction, imaging quality improvement, and optical path optimization.

[0127] In some examples of the present application, each lens in the projection lens module is a spherical lens.

[0128] In one example, all the lenses in the projection lens are glass spherical mirrors, that is, the first lens 1 to the tenth lens 10 are all glass lenses.

[0129] The design of spherical lenses can meet the high imaging quality requirements of projection lenses. At the same time, their manufacturing cost is relatively low, which is conducive to reducing the production cost of the overall projection lens module. Spherical lenses have good optical performance, can reduce the scattering and absorption of light, and improve the clarity and contrast of imaging. In addition, the manufacturing cost of spherical lenses is low, which is beneficial to reducing the production cost of the overall lens.

[0130] Glass materials have high thermal stability and chemical stability, and can maintain stable optical performance under different environmental conditions. This helps to enhance the stability of the projection lens module and improve the reliability and service life of the product.

[0131] Generally speaking, the design of glass spherical lenses is simple and easy to be combined with other optical elements.

[0132] In some examples of the present application, refer to Figure 4, the projection lens module further includes a galvanometer 12 and a prism 13 that are sequentially arranged on the object side of the tenth lens 10.

[0133] The galvanometer 12 and the prism 13, together with the aforementioned first lens 1 to the tenth lens 10, constitute the projection lens of the projection lens module of the present application.

[0134] Among them, whether the galvanometer 12 is provided depends on specific application requirements.

[0135] Among them, the prism 13 is used to further adjust the direction of light. By reasonably designing the shape and angle of the prism, precise control of the light path can be achieved to meet specific projection requirements.

[0136] The prism 13 can be designed as a total internal reflection prism (TIR prism).

[0137] In some examples of the present application, refer to Figure 4 , the projection lens module further includes a display unit 14 and a glass plate 15, and the glass plate 15 is located between the display unit 14 and the prism 13.

[0138] Among them, the display unit 14, as a component of the projection lens module, is responsible for generating and providing the light for projection imaging to the projection lens.

[0139] The display unit 14 is, for example, a high-resolution display device, such as an LCD, DLP, or LCOS, etc., and can generate high-quality image signals.

[0140] Among them, the glass plate 15 is placed between the display unit 14 and the prism 13, and is used to ensure that the light emitted from the display unit 14 can efficiently pass through the subsequent prism and lens group, and finally form a high-quality projection image. The glass plate 15 reduces the loss and interference of light during transmission through its characteristics such as high light transmittance and low reflectivity, which is beneficial to improving the brightness and contrast of the projection picture.

[0141] 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: 2.9 < TTL / D1 < 3.7.

[0142] In the examples provided in this application, the projection lens module not only includes two lens groups and the aperture 11, but also introduces the galvanometer 12, the prism 13, the glass plate 15 and the display unit 14, and further specifies the ratio range (2.9 < TTL / D1 < 3.7) between the total optical length TTL of the projection lens module and the maximum aperture D1 of the lens. The following is a detailed analysis of this design.

[0143] By precisely controlling the ratio range of TTL / D1, it is possible to achieve a compact design of the projection lens module while ensuring sufficient optical performance. The setting of this ratio range ensures that the projection lens module has a sufficient working distance and imaging range, without affecting the portability and usage scenarios of the projector due to excessive volume and weight.

[0144] In some examples of this application, referring to Figure 4 and Table 2, the focal length of the projection lens module is 23.5mm - 35.1mm, the projection ratio TR is 4.5 - 6.7, the relative aperture is 1 / 1.7, the Offset is 0%, the pixel size is 5.4μm, the field of view angle is 4.7° - 7.3°, the image plane size is 5.3mm - 6.6mm, and the working wavelength range is 455nm - 630nm.

[0145] Specifically, referring to Table 2, Table 2 shows the Figure 4 optical parameters of the provided projection lens module.

[0146] Table 2

[0147] According to this example of the present application, the focal length range of the projection lens module is between 23.5mm and 35.1mm, enabling the projection lens module to cover a relatively wide projection distance and screen size, meeting the requirements of different application scenarios.

[0148] The projection ratio TR of the projection lens module is between 4.5 and 6.7, meaning that a large screen size can be achieved within a short projection distance, which is particularly important for places with limited space.

[0149] The field of view angle of the projection lens module is between 4.7° and 7.3°. Although not particularly large, it provides a certain viewing angle range on the premise of ensuring image quality. The design of this field of view angle meets the requirements of commercial micro-projection devices.

[0150] The working wavelength range is 455nm to 630nm, which covers most of the visible light range, enabling the projection lens module provided by the embodiments of the present application to present rich colors and natural picture effects.

[0151] The image plane size is between 5.3mm and 6.6mm, ensuring the clarity and fineness of the projection image.

[0152] The overall optical length TTL of the projection lens module provided by the embodiments of the present application is only 80mm, and the maximum effective aperture D1 is 24mm, making the overall structure of the projection lens module compact and facilitating integration into a micro-projector.

[0153] Through precise optical design and parameter control, the projection lens module can achieve high-quality imaging effects, meeting the high requirements of users for the quality of the projection image.

[0154] Table 2 shows the optical parameter design in a certain state (such as the initial state). It should be noted that the projection lens module provided by the embodiments of the present application includes but is not limited to the optical design in Table 2. For others, reference can be made to Embodiments 1 to 3 in the following text.

[0155] See Figure 5 , Figure 5 is the distortion diagram of the projection lens module provided for the above example of the present application, and the absolute value of its distortion is less than 0.7%.

[0156] See Figure 6 , Figure 6 is the MTF diagram of the projection lens module provided for the above example of the present application, and the MTF > 0.5 at 93lp / mm.

[0157] According to another embodiment of the present application, a micro-projection device is provided, and the micro-projection device includes a housing and the projection lens module as described above.

[0158] The micro-projection device provided by the embodiments of the present application can be applied to commercial micro-projection devices.

[0159] The specific implementation manners of the micro-projection device in the embodiments of the present application can refer to the respective embodiments of the above projection lens module, and thus at least have all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0160] The projection lens module of the present application will be described below through Embodiments 1 to 3 respectively. Among them, Embodiment 1 is the long-focus state of the projection lens module, Embodiment 2 is the medium-focus state of the projection lens module, and Embodiment 3 is the short-focus state of the projection lens module.

[0161] Embodiment 1 See Figure 7, the projection lens module provided in Embodiment 1 includes a projection lens, a glass plate 15, and a display unit 14 arranged in sequence along the same optical axis; wherein, the display unit 14 is used to provide light for projection imaging to the projection lens, and the projection lens is used to perform projection imaging on the light emitted by the display unit 14; The projection lens includes a first lens group, a second lens group, and a diaphragm 11 arranged along the same optical axis; The first lens group includes a first doublet lens, a third lens 3, a second doublet lens, a sixth lens 6, and a seventh lens 7 arranged along the optical axis. The first doublet lens has a positive optical power, the third lens 3, the sixth lens 6, and the seventh lens 7 all have positive optical powers, and the second doublet lens has a negative optical power; wherein, the first doublet lens is composed of a first lens 1 and a second lens 2 glued together. The first lens 1 has a negative optical power, and the second lens 2 has a positive optical power; the second doublet lens is composed of a fourth lens 4 and a fifth lens 5 glued together. The fourth lens 4 has a negative optical power, and the fifth lens 5 has a positive optical power; Wherein, the third lens 3 and the second doublet lens form a linkage zoom lens group and are configured to be able to move synchronously along the optical axis, and the distance between the two remains constant, so that the projection lens module can achieve zoom within a predetermined focal length range; The second lens group includes an eighth lens 8, a ninth lens 9, and a tenth lens 10 arranged in sequence along the optical axis. The eighth lens 8 has a negative optical power, and the ninth lens 9 and the tenth lens 10 both have positive optical powers; The first lens 1 to the tenth lens 10 are all glass spherical lenses; The diaphragm 11 is located between the seventh lens 7 and the eighth lens 8; The projection lens further includes a galvanometer 12 and a prism 13, which are arranged in sequence between the tenth lens 10 and the glass plate 15.

[0162] The projection lens module provided in this Embodiment 1 is in the telephoto mode.

[0163] See Figure 7 , Figure 7 For the optical parameters of the shown projection lens module, please refer to Table 3 below.

[0164] Table 3

[0165] The projection lens module provided in this Embodiment 1 has optical performance as Figures 8 to 11 shown:Figure 8 It is a schematic diagram of a spot diagram. Figure 9 It is an MTF curve graph. Figure 10 It is a field curvature and distortion graph. Figure 11 It is a lateral chromatic aberration graph.

[0166] See Figure 8 , for the projection lens module provided in Embodiment 1, the maximum value of the image points in the spot diagram is less than 4 μm.

[0167] See Figure 9 , for the projection lens module provided in Embodiment 1, the MTF is > 0.5 at 93 lp / mm.

[0168] See Figure 10 , for the projection lens module provided in Embodiment 1, the maximum distortion occurs at a 1° field of view, and the absolute value is less than 0.7%.

[0169] See Figure 11 , for the projection lens module provided in Embodiment 1, the maximum chromatic aberration value is less than 2 μm.

[0170] Embodiment 2 See Figure 12 , the projection lens module provided in Embodiment 2 includes a projection lens, a glass plate 15, and a display unit 14 that are sequentially arranged along the same optical axis; wherein, the display unit 14 is used to provide light for projection imaging to the projection lens, and the projection lens is used to perform projection imaging on the light emitted by the display unit 14; The projection lens includes a first lens group, a second lens group, and a diaphragm 11 that are arranged along the same optical axis; The first lens group includes a first doublet lens, a third lens 3, a second doublet lens, a sixth lens 6, and a seventh lens 7 that are arranged along the optical axis. The first doublet lens has a positive optical power, the third lens 3, the sixth lens 6, and the seventh lens 7 all have positive optical powers, and the second doublet lens has a negative optical power; wherein, the first doublet lens is composed of a first lens 1 and a second lens 2 glued together. The first lens 1 has a negative optical power, and the second lens 2 has a positive optical power; the second doublet lens is composed of a fourth lens 4 and a fifth lens 5 glued together. The fourth lens 4 has a negative optical power, and the fifth lens 5 has a positive optical power; Wherein, the third lens 3 and the second doublet lens form a linkage zoom lens group and are configured such that the two can move synchronously along the optical axis, and the distance between the two remains constant, so that the projection lens module can achieve zoom within a predetermined focal length range; The second lens group includes an eighth lens 8, a ninth lens 9, and a tenth lens 10 that are sequentially arranged along the optical axis. The eighth lens 8 has a negative optical power, and the ninth lens 9 and the tenth lens 10 both have positive optical powers; The first lens 1 to the tenth lens 10 are all glass spherical mirrors; The diaphragm 11 is located between the seventh lens 7 and the eighth lens 8; The projection lens further includes a galvanometer scanner 12 and a prism 13, which are sequentially arranged between the tenth lens 10 and the glass plate 15.

[0171] The projection lens module provided in Embodiment 2 is in the medium focal length mode.

[0172] See Figure 12 , Figure 12 For the optical parameters of the projection lens module shown, please refer to Table 4 below.

[0173] Table 4

[0174] For the projection lens module provided in this Embodiment 2, its optical performance is as Figures 13 to 16 shown: Figure 13 is a spot diagram schematic diagram, Figure 14 is an MTF curve graph, Figure 15 is a field curvature and distortion graph, Figure 16 is a lateral chromatic aberration graph.

[0175] See Figure 13 , for the projection lens module provided in this Embodiment 2, the maximum value of the image points in the spot diagram is less than 4 μm.

[0176] See Figure 14 , for the projection lens module provided in this Embodiment 2, the MTF > 0.4 at 93 lp / mm.

[0177] See Figure 15 , for the projection lens module provided in this Embodiment 2, the maximum distortion occurs at a 1° field of view, and the absolute value is less than 0.15%.

[0178] See Figure 16 , for the projection lens module provided in this Embodiment 2, the maximum chromatic aberration value is less than 2 μm.

[0179] Embodiment 3 See Figure 17 , the projection lens module provided in Embodiment 3 includes a projection lens, a glass plate 15, and a display unit 14 that are sequentially arranged along the same optical axis; wherein, the display unit 14 is used to provide light for projection imaging to the projection lens, and the projection lens is used to perform projection imaging on the light emitted by the display unit 14; The projection lens includes a first lens group, a second lens group, and a diaphragm 11 arranged along the same optical axis; The first lens group includes a first doublet lens, a third lens 3, a second doublet lens, a sixth lens 6, and a seventh lens 7 arranged along the optical axis. The first doublet lens has a positive optical power, and the third lens 3, the sixth lens 6, and the seventh lens 7 all have positive optical powers. The second doublet lens has a negative optical power. Among them, the first doublet lens is composed of a first lens 1 and a second lens 2 glued together. The first lens 1 has a negative optical power, and the second lens 2 has a positive optical power. The second doublet lens is composed of a fourth lens 4 and a fifth lens 5 glued together. The fourth lens 4 has a negative optical power, and the fifth lens 5 has a positive optical power; Among them, the third lens 3 and the second doublet lens form a linkage zoom lens group and are configured to be able to move synchronously along the optical axis, and the distance between them remains constant, so that the projection lens module can achieve zoom within a predetermined focal length range; The second lens group includes an eighth lens 8, a ninth lens 9, and a tenth lens 10 arranged in sequence along the optical axis. The eighth lens 8 has a negative optical power, and the ninth lens 9 and the tenth lens 10 both have positive optical powers; The first lens 1 to the tenth lens 10 are all glass spherical mirrors; The diaphragm 11 is located between the seventh lens 7 and the eighth lens 8; The projection lens further includes a galvanometer 12 and a prism 13, which are sequentially arranged between the tenth lens 10 and the glass plate 15.

[0180] The projection lens module provided in Embodiment 3 is in the short - focal mode.

[0181] See Figure 17 , Figure 17 For the optical parameters of the projection lens module shown, please refer to Table 5 below.

[0182] Table 5

[0183] The projection lens module provided in Embodiment 3 has optical performance as Figures 18 to 21 shown: Figure 18 is a spot diagram schematic, Figure 19 is an MTF curve graph, Figure 20 is a field curvature and distortion graph, Figure 21 is a lateral chromatic aberration graph.

[0184] See Figure 18, for the projection lens module provided in Embodiment 3, the maximum value of the image points in the spot diagram is less than 4 μm.

[0185] See Figure 19 , for the projection lens module provided in Embodiment 3, the MTF is > 0.5 at 93 lp / mm.

[0186] See Figure 20 , for the projection lens module provided in Embodiment 3, the maximum distortion occurs at the 1st field of view, and the absolute value is less than 0.7%.

[0187] See Figure 21 , for the projection lens module provided in Embodiment 3, the maximum chromatic aberration is less than 2 μm.

[0188] The differences between the various embodiments were mainly described in the above embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a more optimal embodiment. Considering the simplicity of the writing, it will not be elaborated here.

[0189] Although some specific embodiments of the present application have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can 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 (11) 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, a third lens (3), a second doublet lens, a sixth lens (6) and a seventh lens (7) which are arranged in sequence along the optical axis, wherein the first doublet lens, the third lens (3), the sixth lens (6) and the seventh lens (7) all have positive focal power, and the second doublet lens has negative focal power; The second lens group comprises an eighth lens (8), a ninth lens (9) and a tenth lens (10) which are arranged in sequence along the optical axis, wherein the eighth lens (8) has a negative optical focal length, and the ninth lens (9) and the tenth lens (10) both have a positive optical focal length; The aperture (11) is located between the seventh lens (7) and the eighth lens (8); The third lens (3) and the second doublet lens form a linked zoom lens group, and are configured so that the two can move synchronously along the optical axis, and the distance between them remains constant, so that the projection lens module can achieve zooming within a predetermined focal length range.

2. The projection lens module according to claim 1, characterized in that: The second double-cemented lens is composed of a fourth lens (4) and a fifth lens (5) cemented together, wherein the fourth lens (4) has a negative optical focal length, the fifth lens (5) has a positive optical focal length, and the refractive index N4 of the fourth lens (4) is lower than the refractive index N5 of the fifth lens (5).

3. The projection lens module according to claim 1, characterized in that: The sag height at the maximum aperture on the object side of the third lens (3) is S1, and the sag height at the maximum aperture on the image side is S2, and the ratio of S1 to S2 satisfies: 1.3<S2 / S1<2.

4.

4. The projection lens module according to claim 1 or 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 the following: 90°<(A1+A2) / 2<110° and 0.93<A1 / A2<1.

08.

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

6. The projection lens module according to claim 5, characterized in that: The central thickness T' of the first double-cemented lens and the total optical length TTL of the projection lens module satisfy the following: 5.5%<T' / TTL<7.9%.

7. The projection lens module according to claim 5, characterized in that: In the first lens group, the center thickness T2 of the second lens (2), the center thickness T3 of the third lens (3), the center thickness T6 of the sixth lens (6), and the center thickness T7 of the seventh lens (7) satisfy the following relationship: 3<(T2+T7) / (T3+T6)<3.

8.

8. The projection lens module according to claim 1 or 7, characterized in that: In the first lens group, the central thickness T7 of the seventh lens (7) and the total optical length TTL of the projection lens module satisfy the following relationship: 5.62%<T7 / TTL<8.12%.

9. The projection lens module according to claim 1, characterized in that: In the second lens group, the central thickness T9 of the ninth lens (9) and the total optical length TTL of the projection lens module satisfy the following relationship: 6.3%<T9 / TTL<8.8%.

10. The projection lens module according to claim 9, characterized in that: The angle between the tangent line at the maximum aperture of the object side surface of the ninth lens (9) and the optical axis is A3, and the angle between the tangent line at the maximum aperture of the image side surface and the optical axis is A4, and A3 and A4 satisfy the following: 110°<(A3+A4) / 2<130° and 0.75<A3 / A4<1.

26.

11. The projection lens module according to claim 1, 9 or 10, characterized in that: The central thickness T8 of the eighth lens (8), the central thickness T9 of the ninth lens (9), and the central thickness T10 of the tenth lens (10) satisfy the following relationship: 6<(T9+T10) / T8<9.

5.

12. 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', 50mm≤F'≤72mm; The effective focal length of the third lens (3) is F3, 140mm≤F3≤170m; The effective focal length of the second double cemented lens is F'', -19mm≤F''≤-15mm; The effective focal length of the sixth lens (6) is 35 mm ≤ F6 ≤ 50 mm; The effective focal length of the seventh lens (7) is 20 mm ≤ F7 ≤ 30 mm; The effective focal length of the eighth lens (8) is F8, -11mm≤F8≤-8mm; The effective focal length of the ninth lens (9) is F9, 30 mm ≤ F9 ≤ 40 mm; The effective focal length of the tenth lens (10) is F10, 18mm≤F10≤27mm; Each lens in the projection lens module is a glass spherical lens.

13. The projection lens module according to claim 12, characterized in that: The projection lens module further comprises a galvanometer (12), a prism (13), a glass plate (15) and a display unit (14) which are located on the object side of the tenth lens (10) 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: 2.9<TTL / D1<3.

7.

14. The projection lens module according to claim 1, characterized in that: The focal length of the projection lens module is 23.5mm~35.1mm, the projection ratio TR is 4.5~6.7, the relative aperture is 1 / 1.7, the Offset is 0%, the pixel size is 5.4μm, the field of view angle is 4.7°~7.3°, the image plane size is 5.3mm~6.6mm, and the operating band is 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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