Projection lens module and micro-projection device

Abstract

The embodiments of the present application provide a projection lens module and a micro-projection device; 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, a third lens, a second doublet lens, a sixth lens and a seventh lens arranged in sequence along the optical axis, the first doublet lens, the third lens, the sixth lens and the seventh lens are all positive optical focal lengths, and the second doublet lens is negative optical focal lengths; the second lens group includes an eighth lens, a ninth lens and a tenth lens arranged in sequence along the optical axis, wherein the eighth lens is negative optical focal lengths, and the ninth lens and the tenth lens are all positive optical focal lengths; the aperture is located between the seventh lens and the eighth lens; the third lens and the second doublet lens constitute a linked zoom lens group, and are configured so 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 zooming within a predetermined focal length range.

Description

Technical Field

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

[0002] As a crucial tool for commercial display and advertising, optimizing the optical performance of commercial micro-projectors has always been a key focus of industry technological development. In projection optical design, the matching of focal length and field of view directly impacts the projected image's size adjustment range and applicable scenarios. Currently, mainstream commercial micro-projection devices mostly utilize a fixed-focal-length projection lens design. While this approach has a simple optical structure, it has significant limitations. Firstly, the fixed focal length prevents flexible adjustment of the projected image size to suit the specific application scenario. Secondly, to meet varying projection distance requirements, multiple lenses with different focal lengths are often required, increasing equipment cost and maintenance complexity.

[0003] Although some zoom projection lens designs exist in the existing technology, the following technical defects still exist: First, the total optical length of traditional zoom lenses changes significantly during the zoom process, resulting in large fluctuations in the optical machine size and easy mechanical interference with other components inside the equipment; second, to achieve good image quality compensation, most solutions use aspherical lenses or complex lens group structures, which not only increases manufacturing costs but also places higher requirements on the assembly process; in addition, the throw 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 applications like floor projection in front of shops, it's crucial to maintain a compact body size (for concealed installation), while also requiring the projection lens to have a sufficient focal length adjustment range (to accommodate varying storefront spacing) and maintain cost control. These competing requirements make it difficult to achieve a technical balance with existing projection lens solutions. Therefore, developing a zoom projection lens that combines a high throw ratio with a compact size and a largely constant overall optical length has become a pressing technical challenge 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 the image side to the object side along the optical axis;

[0007] 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, wherein the first doublet lens, the third lens, the sixth lens, and the seventh lens all have positive focal power, and the second doublet lens has negative focal power;

[0008] The second lens group includes an eighth lens, a ninth lens, and a tenth lens sequentially arranged along the optical axis, wherein the eighth lens has a negative optical power, and the ninth lens and the tenth lens both have a positive optical power;

[0009] The aperture is located between the seventh lens and the eighth lens;

[0010] The third lens 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 zoom within a predetermined focal length range.

[0011] Optionally, the second doublet lens is composed of a fourth lens and a fifth lens cemented together, wherein the fourth lens has negative optical power, the fifth lens has positive optical power, and the refractive index N4 of the fourth lens is lower than the refractive index N5 of the fifth lens.

[0012] Optionally, the sag height of the object-side surface of the third lens at the maximum aperture is S1, the sag height of the image-side surface of the third lens at the maximum aperture is S2, and the ratio of S1 to S2 satisfies: 1.3<S2 / S1<2.4.

[0013] 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 of the third lens and the optical axis is A2, and A1 and A2 satisfy: 90°<(A1+A2) / 2<110° and 0.93<A1 / A2<1.08.

[0014] Optionally, the first doublet lens is composed of a first lens and a second lens glued together, wherein the first lens has negative optical power, the second lens has positive optical power, and the refractive index N2 of the second lens is lower than the refractive index N1 of the first lens.

[0015] Optionally, a central thickness T' of the first doublet lens and a total optical length TTL of the projection lens module satisfy the following relationship: 5.5%<T' / TTL<7.9%.

[0016] Optionally, in the first lens group, the center thickness T2 of the second lens, the center thickness T3 of the third lens, the center thickness T6 of the sixth lens, and the center thickness T7 of the seventh lens satisfy the following relationship: 3<(T2+T7) / (T3+T6)<3.8.

[0017] Optionally, in the first lens group, a center thickness T7 of the seventh lens and a total optical length TTL of the projection lens module satisfy the following relationship: 5.62%<T7 / TTL<8.12%.

[0018] Optionally, in the second lens group, a center thickness T9 of the ninth lens and a total optical length TTL of the projection lens module satisfy the following relationship: 6.3%<T9 / TTL<8.8%.

[0019] Optionally, the angle between the tangent line at the maximum aperture of the object side surface of the ninth lens and the optical axis is A3, 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: 110°<(A3+A4) / 2<130° and 0.75<A3 / A4<1.26.

[0020] Optionally, a center thickness T8 of the eighth lens, a center thickness T9 of the ninth lens, and a center thickness T10 of the tenth lens satisfy the relationship: 6<(T9+T10) / T8<9.5.

[0021] Optionally, the effective focal length of each lens in the projection lens module satisfies:

[0022] The effective focal length of the first doublet lens is F', 50mm≤F'≤72mm;

[0023] The effective focal length of the third lens is F3, 140mm≤F3≤170m;

[0024] The effective focal length of the second doublet lens is F'', -19mm≤F''≤-15mm;

[0025] The effective focal length of the sixth lens is 35mm≤F6≤50mm;

[0026] The effective focal length of the seventh lens is 20mm≤F7≤30mm;

[0027] The effective focal length of the eighth lens is F8, -11mm≤F8≤-8mm;

[0028] The effective focal length of the ninth lens is F9, 30mm≤F9≤40mm;

[0029] The effective focal length of the tenth lens is F10, 18mm≤F10≤27mm;

[0030] Each lens in the projection lens module is a glass spherical lens.

[0031] Optionally, the projection lens module further includes a galvanometer, a prism, a glass plate, and a display unit that are located on the object side of the tenth lens and are sequentially arranged;

[0032] 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 the following: 2.9<TTL / D1<3.7.

[0033] Optionally, 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.

[0034] In a second aspect, an embodiment of the present application provides a micro-projection device, the micro-projection device comprising:

[0035] casing; and

[0036] The projection lens module as described in the second aspect.

[0037] The beneficial effects of this application are:

[0038] The projection lens module provided in the embodiments of the present application achieves adjustable focal length for the entire module by synchronously moving the positions of the third lens and the second doublet lens along the optical axis. Particularly notably, during zooming, the change rate of the projection lens module's total optical length is controlled within 3.3%, essentially maintaining a constant overall optical length. This design effectively addresses the significant size changes and complex optical structure design issues associated with conventional zoom lenses during zooming. This feature makes the present application particularly suitable for space-constrained micro-projection devices, combining zoom functionality with a compact design.

[0039] This application specifically designs a lens combination and configuration, allowing the use of only ten lenses, including two sets of doublets and six singlets. By designing the focal power distribution of the lenses within the module, this reduces the number of lenses while achieving a large throw ratio (e.g., 4.5-6.7) and a wide focal length range (e.g., 23.5mm-35.1mm), further reducing the complexity of optical design. This optical design ensures high definition and high contrast in the projected image, providing users with an exceptional visual experience.

[0040] It should be emphasized that during the zoom process, the total optical length of the projection lens module provided by this application remains essentially unchanged, which greatly ensures the structural compactness and optical performance stability of the zoom process. At the same time, thanks to the overall optical design optimization of the module, the consistency of image quality during the zoom process is also fully guaranteed, ensuring stable imaging effects at different focal lengths. Whether it is short-distance small-scale projection or long-distance large-scale projection, this application can achieve clear imaging and meet diverse projection needs.

[0041] 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

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0043] Figure 1 Schematic diagram of the projection lens module in different focal length states provided by an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the partial structure of the third lens of the projection lens provided in an embodiment of the present application;

[0045] Figure 3 Schematic diagram of the partial structure of the ninth lens of the projection lens provided in an embodiment of the present application

[0046] Figure 4 A schematic diagram of the optical architecture of a projection lens module provided in an embodiment of the present application;

[0047] Figure 5 for Figure 4 Distortion diagram of the projection lens module in ;

[0048] Figure 6 for Figure 4 MTF diagram of the projection lens module in;

[0049] Figure 7 The structure and optical path diagram of the projection lens module (telephoto) provided in Example 1 of the present application;

[0050] Figure 8 for Figure 7 Dot array diagram of the provided projection lens module;

[0051] Figure 9 for Figure 7 Provided MTF graph of the projection lens module;

[0052] Figure 10 for Figure 7Provided field curvature and distortion diagrams of the projection lens module;

[0053] Figure 11 for Figure 7 Provide vertical axis chromatic aberration diagram of the projection lens module;

[0054] Figure 12 The structure and optical path diagram of the projection lens module (mid-focus) provided in Example 2 of the present application;

[0055] Figure 13 for Figure 12 Dot array diagram of the provided projection lens module;

[0056] Figure 14 for Figure 12 Provided MTF graph of the projection lens module;

[0057] Figure 15 for Figure 12 Provided field curvature and distortion diagrams of the projection lens module;

[0058] Figure 16 for Figure 12 Provide vertical axis chromatic aberration diagram of the projection lens module;

[0059] Figure 17 The structure and optical path diagram of the projection lens module (short focus) provided in Example 3 of the present application;

[0060] Figure 18 for Figure 17 Dot array diagram of the provided projection lens module;

[0061] Figure 19 for Figure 17 Provided MTF graph of the projection lens module;

[0062] Figure 20 for Figure 17 Provided field curvature and distortion diagrams of the projection lens module;

[0063] Figure 21 for Figure 17 Provide vertical axis chromatic aberration diagram of the projection lens module;

[0064] Figure 22 This is a diagram showing the correspondence between the focal length of the projection lens module and the air gap A and air gap B provided in an embodiment of the present application.

[0065] Description of reference numerals:

[0066] 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 DESCRIPTION

[0067] 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.

[0068] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0069] 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.

[0070] 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.

[0071] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0072] The projection lens module and the micro-projection device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0073] According to one embodiment of the present application, a projection lens module is provided. Figure 1 and Figure 4The projection lens module comprises, in order from the image side to the object side along the optical axis, a first lens group, an aperture 11, and a second lens group. The first lens group comprises a first doublet, a third lens 3, a second doublet, a sixth lens 6, and a seventh lens 7, arranged in sequence along the optical axis. The first doublet, the third lens 3, the sixth lens 6, and the seventh lens 7 all have positive focal power, while the second doublet has negative focal power. The second lens group comprises 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 negative focal power, while the ninth lens 9 and the tenth lens 10 all have positive focal power. 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 constitute a linked zoom lens group and are configured to move synchronously along the optical axis with a constant spacing between them, enabling the projection lens module to achieve zooming within a predetermined focal length range.

[0074] 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 comprises the aforementioned first and second lens groups, and an aperture 11 located between the two groups (the position of the aperture 11 is fixed, meaning the distance between the aperture 11 and the two lenses is constant). The projection lens is located on the light path of the display unit 14 and is responsible for receiving light emitted from the display unit 14 (this light is specifically used for projection display) and performing other processes such as modulation and focusing on this light. Through this series of optical operations, the light emitted by the display unit 14 is guided and projected onto the imaging surface, ultimately presenting a clear projection image.

[0075] Specifically, see Figure 1 and Figure 4 The projection lens module provided by the embodiment of the present application includes 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 (located 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 (located 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.

[0076] It should be noted that, see Figure 4In the optical architecture provided in 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.

[0077] The first lens assembly provided in the embodiments of the present application is described in detail as follows.

[0078] The first lens group provided in the embodiment of the present application is one of the components of the projection lens module (or projection lens). The first lens group mainly consists of the first lens 1 to the seventh lens 7. Figure 4 The first lens 1 and the second lens 2 are cemented together to form a first doublet lens, the fourth lens 4 and the fifth lens 5 are cemented together to form a second doublet lens, and the third lens 3, the sixth lens 6, and the seventh lens 7 are all provided separately. These seven lenses in the first lens group each play an important role in the entire projection lens module.

[0079] The optical power of each lens in the first lens group is configured as follows: the first doublet lens with positive optical power is located at the front end (i.e., close to the image side, see Figure 4 (left side in the figure), followed by the third lens 3 with positive focal power, then the second doublet lens with negative focal power, and finally the sixth lens 6 and the seventh lens 7, both with positive focal power. This positive-positive-negative-positive-positive focal power configuration in the first lens group effectively balances aberrations such as spherical aberration, coma, and field curvature. Specifically:

[0080] The front-mounted first doublet (positive power) and third lens element 3 (positive power) provide primary focusing power, but introduce positive spherical aberration and positive field curvature. The subsequent second doublet (negative power) offsets the positive spherical aberration introduced by the front lens element, while also correcting chromatic aberrations (such as axial chromatic aberration) through the refractive index differences between the cemented surfaces. The rear-mounted sixth lens element 6 (positive power) and seventh lens element 7 (positive power) further optimize image flatness and, in conjunction with the position of the aperture stop 11, control astigmatism.

[0081] The focal power configuration of the first lens group provides an excellent optical foundation for the synchronous movement of the positive and negative lenses (i.e., the zoom process), ensuring stable image quality during the zoom process. This allows the projection lens module to maintain excellent imaging characteristics at different focal lengths, meeting the needs of various projection scenarios.

[0082] While maintaining high performance, the optical power configuration of the first lens group also helps to achieve a miniaturized design of the entire projection lens module, thereby meeting the needs of micro-projection equipment.

[0083] In the first lens group, the third lens 3 and the second doublet lens constitute a linked 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 linked zoom lens group and the first doublet lens, and the air gap B between the linked zoom lens group and the sixth lens 6, see Figure 7 、 Figure 12 and Figure 17 , which is the key to achieving zooming of the projection lens module in this application. It is worth noting that during the zooming process, the distance between the third lens 3 and the second doublet lens remains unchanged.

[0084] The second lens group provided in the embodiment of this application is shown in FIG. Figure 1 and Figure 4 , another component of the projection lens module. The second lens group primarily consists of the eighth lens 8, the ninth lens 9, and the tenth lens 10. In the lens arrangement of the second lens group, the negative-power eighth lens 8 is located near the aperture 11, followed by the positive-power ninth lens 9 and the tenth lens 10. This negative-positive-positive power configuration helps further correct aberrations.

[0085] Specifically, the eighth lens element (8) (negative power) is located behind the aperture 11. Its primary function is to offset residual spherical aberration and field curvature from the front lens group (i.e., the first lens group). Its divergent effect as a negative lens evens out the image curvature caused by the strong positive power of the first lens group. In conjunction with the aperture (fixed between the two lens groups), it controls the principal ray angle and reduces astigmatism and coma. The ninth lens element (positive power) and the tenth lens element (positive power) serve as the converging elements of the rear lens group (the second lens group). They are primarily responsible for re-converging the light rays onto the imaging plane, compensating for the excessive divergence of the eighth lens element 8 and ensuring a positive total optical power for the projection lens module. The second lens group's optical power configuration (negative-positive-positive) synergizes with the first lens group's (front lens group) power configuration to achieve high optical performance.

[0086] During the zooming 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 ) / TTL0≤3.3%. This indicates that during the zoom process, the physical size of the projection lens module changes very little and remains basically unchanged.

[0087] The projection lens module provided in the embodiment of the present application has the remarkable feature of being able to realize the zoom function, and during the zooming process, the total optical length of the projection lens module at different focal lengths can be kept basically consistent. Figure 1In the three operating modes of short-throw, medium-throw, and long-throw, the projection lens module provided by the embodiments of the present application maintains a substantially consistent length along the optical axis (i.e., the total optical length). This advantage demonstrates the effectiveness of controlling the rate of change of the total optical length, meaning that regardless of changes in focal length, the overall dimensions of the projection lens module (along the optical axis) can remain relatively stable.

[0088] In the projection lens module design provided in 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 a zoom function while keeping the total optical length essentially unchanged. The principle behind this can be analyzed from the perspectives of optical path control and optical power compensation, as detailed below.

[0089] Regarding the movement of the third lens 3:

[0090] The third lens 3 has positive focal length and serves as a strong focusing optical element in the first lens group. Its movement will directly change the focal length of the projection lens module. Figure 17 When the third lens 3 moves toward 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 is shortened. Figure 12 When the third lens 3 moves toward 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.

[0091] Regarding the movement of the second doublet lens: the second doublet lens and the third lens 3 move synchronously, 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 toward the image side, the second doublet lens will move synchronously to compensate for the image plane displacement through divergence.

[0092] In short, in the projection lens module provided in the embodiment of the present application, the coordinated movement of the positive and negative lenses forms an "optical compensation zoom" mechanism, which keeps the position of the imaging surface stable by offsetting the optical focal length, thereby avoiding changes in the total length.

[0093] It can be seen that, in the projection lens module provided in the embodiment of the present application, although the focal length changes during the zooming process, the total optical length of the projection lens module can remain relatively stable.

[0094] When a traditional zoom lens is zoomed, its physical dimensions change significantly due to the change in focal length. This can cause the overall size of the module (or optical machine) to be excessively large, increasing the size and weight of the projection equipment and potentially limiting its application in space-constrained scenarios. The projection lens module designed in this application effectively avoids this problem by controlling the rate of change of the total optical length.

[0095] In projection equipment, the projection lens module is often surrounded by other key components, such as light sources and cooling systems. The dimensional changes of traditional zoom lenses during zooming can cause collisions or interference with these components, impacting the normal operation of the projection equipment. The optical design of this application effectively prevents such issues by maintaining the dimensional stability of the projection lens module during zooming, thereby improving the reliability and stability of the equipment.

[0096] In the present application, the third lens 3 and the second double-cemented lens serve as the core components of the zoom mechanism. By regulating the positions of the two in the optical path, the optical power distribution ratio in the entire projection lens module is changed. This change directly affects the convergence path and focal length of the light, thereby achieving a focal length adjustment range of 23.5mm to 35.1mm. That is, by adjusting the positions of the third lens 3 and the second double-cemented lens on the optical axis, it is possible to flexibly adapt to different projection distances and picture 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 zoom process. Whether in long focus, medium focus or short focus state, high-quality projection images can be obtained to meet the requirements of different projection distances and projection sizes.

[0097] See also Figure 1 and Figure 4 In the projection lens module, the aperture 11 is specifically located between the seventh lens 7 and the eighth lens 8, and is used to limit the range of light passing through, control the size of the imaging beam, and thus improve the imaging quality.

[0098] The projection lens module provided in the embodiment of the present application can support zoom functions from long focus, medium focus to short focus. Its focal length adjustment range can cover 23.5mm to 35.1mm, and the throw ratio can reach 4.5 to 6.7, providing users with great flexibility and convenience.

[0099] The projection lens module provided in the embodiment of the present application has lens length stability, see Figure 1The projection lens module maintains a roughly consistent total optical length in its three operating modes: long, medium, and short. This design advantage significantly reduces module (optical and mechanical) size changes caused by zooming, effectively avoiding the risk of collision or interference between the projection lens module and other equipment components during zooming. This stability not only improves the overall reliability of the projection equipment, but also simplifies the mechanical design and reduces manufacturing costs.

[0100] In one example, see Figure 7 , the projection lens module is in the telephoto 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. 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.

[0101] On the contrary, see Figure 17 When the projection lens module is in the short-focus state, the third lens 3 and the second doublet lens will approach the first doublet lens along the optical axis. At this time, the air gap A is significantly reduced, while the air gap B is significantly increased.

[0102] See also Figure 22 Table 1 intuitively shows the dynamic relationship between air gap A, air gap B and the focal length of the projection lens module. Figure 22 As can be seen in the figure, as air gap A decreases and air gap B increases, the focal length of the projection lens module decreases accordingly, achieving a short-focus imaging effect. Conversely, when air gap A increases and air gap B decreases, the focal length of the projection lens module increases accordingly, achieving a long-focus state. This air gap adjustment mechanism ensures that the projection lens module maintains excellent imaging performance at different focal lengths.

[0103] Table 1 shows the corresponding relationship between the air gap A, the air gap B, and the focal length of the projection lens module.

[0104] Table 1

[0105]

[0106] In some examples of this application, see Figure 4 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 negative optical power, the fifth lens 5 has 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.

[0107] In the example provided herein, the second doublet lens is composed of a fourth lens 4 with negative optical power and a fifth lens 5 with positive optical power, cemented together. The fourth lens 4 is a negative lens, diverging light. The fifth lens 5 is a positive lens, converging light. By cementing these two lenses with opposite optical powers together, chromatic aberration introduced by a single lens can be corrected, thereby improving the color reproduction and clarity of the projected image. Furthermore, because 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 reduce aberrations such as spherical aberration and coma, thereby improving image quality.

[0108] In the example provided in this application, the second double-cemented lens can effectively correct chromatic aberration and aberration, and maintain stable optical performance at different focal lengths, so that the entire projection lens module can provide high-quality projection effects in different working environments and usage conditions.

[0109] In one example, the refractive index N4 of the fourth lens element 4 (negative lens) of the second doublet is in the range of 1.55 to 1.73, and the refractive index N5 of the fifth lens element 5 (positive lens) is in the range of 1.78 to 1.83. In this second doublet, the higher refractive index of the positive lens element, i.e., the fifth lens element 5, can more effectively converge light, improving light utilization. The relatively lower refractive index of the negative lens element, i.e., the fourth lens element 4, can more evenly diverge light, reducing light loss and distortion during propagation. Furthermore, the choice of refractive indices for the positive and negative lenses does not significantly increase production costs.

[0110] In some examples of this application, see Figure 4 The sag height of the object side of the third lens 3 at the maximum aperture is S1, and the sag height of the image side of the third lens 3 at the maximum aperture is S2. The ratio of S1 to S2 satisfies: 1.3<S2 / S1<2.4.

[0111] In the example provided in this application, the surface shape of the third lens 3 is regulated, specifically describing the proportional relationship between the sagittal height S1 at the maximum aperture of the object side of the third lens 3 and the sagittal height S2 at the maximum aperture of the image side, i.e., 1.3 < S2 / S1 < 2.4. In the projection lens module provided in the embodiment of this application, the third lens 3 is designed to have positive optical power and has the ability to converge light. By further controlling the above-mentioned ratio range of S2 to S1, the following technical effects can be achieved.

[0112] (1) Optimization of aberration correction:

[0113] The sagittal heights of the two lens surfaces are important parameters that describe the lens's surface shape and have a direct impact on the aberration correction of the optical system. In this application, by adjusting the ratio of S2 to S1, the light-converging ability of the third lens 3 can be optimized, thereby more effectively correcting aberrations such as spherical aberration and chromatic aberration.

[0114] For the third lens element 3 with positive refractive power, a larger value of S2 / S1 means that the radius of curvature of the image-side surface is relatively larger, which helps to reduce the refraction angle of the incident light and reduce the possibility of aberration.

[0115] (2) Improvement of optical performance:

[0116] By controlling the ratio of S2 to S1, the optical performance of the third lens 3, including key optical parameters such as focal length, can be optimized. This helps improve the optical performance of the entire projection lens module, resulting in clearer and more detailed projected images. Furthermore, the optimized sag ratio helps achieve a more uniform spot distribution, improving the contrast and brightness uniformity of the projected image.

[0117] (3) Maintaining the compactness of the projection lens module:

[0118] By controlling the sagittal ratio of the image-side and object-side surfaces of the third lens 3, a compact design of the projection lens module can be achieved without sacrificing optical performance. The optimized sagittal ratio helps reduce unnecessary space occupation, making the projection lens module more compact and lightweight.

[0119] In some examples of this application, see Figure 2 The angle between the tangent line at the maximum aperture of the object side surface 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 surface and the optical axis is A2. A1 and A2 satisfy: 90°<(A1+A2) / 2<110° and 0.93<A1 / A2<1.08.

[0120] In the example provided in this application, the surface design of the third lens 3 is further controlled. Specifically described is the relationship between the angle A1 between the tangent line at the maximum aperture of the image-object side of the third lens 3 and the optical axis, and the angle A2 between the tangent line at the maximum aperture of the image-object side and the optical axis. These two angles meet specific conditions, namely 90° < (A1 + A2) / 2 < 110° and 0.93 < A1 / A2 < 1.08. This design is intended to optimize the optical performance of the projection lens module.

[0121] In the example provided in this application, by controlling the ratio of A1 to A2 and their sum, the refraction path of light by the third lens 3 can be optimized, thereby more effectively correcting aberrations such as spherical aberration, coma, etc.

[0122] In particular, when (A1+A2) / 2 is between 90° and 110°, it helps balance the refraction and reflection of light on the surface of the third lens element 3, reducing aberrations. Furthermore, controlling the A1 / A2 ratio between 0.93 and 1.08 ensures that the refraction angles of light on the object side and image side are neither too large nor too small, further improving aberration correction.

[0123] By controlling the relationship between A1 and A2, the optical performance of the third lens 3, such as key optical parameters like focal length and magnification, can be optimized. This helps improve the optical performance of the entire projection lens module, resulting in clearer and more detailed projected images. Furthermore, by controlling the relationship between A1 and A2, a compact design of the projection lens module can be achieved without sacrificing optical performance.

[0124] In some examples of this application, see Figure 4 The first doublet lens is composed of a first lens 1 and a second lens 2 glued together, wherein the first lens 1 has negative optical power, the second lens 2 has 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.

[0125] In the example provided herein, the first lens 1 is a negative lens, diverging light; the second lens 2 is a positive lens, converging light. Furthermore, 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 difference in refractive index helps optimize the optical performance of the first doublet lens.

[0126] In the example provided in this application, by cementing a negative-power first lens 1 with a positive-power second lens 2, aberrations 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.

[0127] The negative-power first lens 1 diverges light, while the positive-power second lens 2 converges it. By gluing these two lenses together and adjusting optical parameters such as refractive index, the light propagation path and convergence point can be controlled to achieve the desired projection effect.

[0128] Because the refractive index N2 of the second lens element (positive lens) 2 is lower than the refractive index N1 of the first lens element (negative lens), meaning the positive lens has a lower focal length than the negative lens, this design can further optimize the optical performance of the resulting first doublet. For example, it can reduce chromatic aberration and increase light transmittance, thereby enhancing the optical performance of the entire projection lens module.

[0129] In the projection lens module provided in the embodiment of the present application, the use of 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 equipment.

[0130] Because the first double-cemented 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 feature is crucial for commercial micro projectors, as they need to continuously provide high-quality projection effects under various complex and changing environmental conditions to meet the needs of different users and application scenarios. By optimizing the optical performance of the first double-cemented lens, the projection lens module provided in this application ensures that clear, sharp, and color-accurate projection images can be output under different focal lengths and lighting conditions.

[0131] In one example, the refractive index N1 of the first lens 1 (negative lens) of the first doublet lens is in the range of 1.78 to 1.83, and the refractive index N2 of the second lens 2 (positive lens) is in the range of 1.55 to 1.73.

[0132] Designing the negative lens' refractive index N1 to a high range of 1.78-1.83 (a high refractive index) helps disperse short-wavelength light, while designing the positive lens' refractive index N2 to a low range of 1.55-1.73 (a low refractive index) enhances the convergence of long-wavelength light. This refractive index combination effectively corrects chromatic aberration, thereby improving the color accuracy of the projected image. The high refractive index of the negative lens allows for a smaller surface curvature, helping to reduce aberrations such as spherical aberration and coma. Simultaneously, the low refractive index of the positive lens, combined with its appropriate curvature, further corrects these aberrations, enhancing image quality. The high refractive index of the negative lens effectively disperses light, while the low refractive index of the positive lens more gently converges it. This combination ensures that the first doublet maintains excellent light control capabilities at various focal lengths, ensuring excellent brightness and contrast in the projected image. Furthermore, using a high refractive index material for the negative lens reduces the thickness and volume of the lens while maintaining the same optical performance, thereby enabling a more compact projection lens module design.

[0133] It should be noted that the performance of the first doublet lens, a key component of the projection lens module, directly impacts the imaging quality of the entire projection lens module. By controlling the refractive index range of first lens 1 and second lens 2, it is possible to ensure that the first doublet lens provides excellent optical performance at different focal lengths, thereby supporting the entire projection lens module in achieving high-quality projection effects.

[0134] The projection lens module provided in the embodiments of the present application utilizes two sets of doublet lenses: a first doublet lens and a second doublet lens. Both the first and second doublet lenses effectively correct chromatic aberration through the combination of negative and positive lenses within them. Furthermore, due to differences in the refractive indices of the materials used, the negative and positive lenses within each doublet lens have different diverging and converging effects on light of different wavelengths. These effects, acting together across the entire projection lens module, significantly reduce chromatic aberration and improve the color accuracy of the projected image.

[0135] In some examples of the present application, the center thickness T' of the first doublet lens and the total optical length TTL of the projection lens module satisfy the following relationship: 5.5%<T' / TTL<7.9%.

[0136] The first doublet lens is one of the components of the projection lens module. Control of the center thickness T' of the first doublet lens has an important impact on the aberration correction, chromatic aberration compensation, and light focusing ability and compactness of the entire projection lens module.

[0137] Specifically, by controlling the ratio of T' to TTL within the aforementioned range, light can be well modulated as it passes through the first doublet lens, thereby optimizing the optical performance of the projection lens module. This design helps improve the clarity and contrast of the projected image, resulting in a more detailed and realistic projection effect. Furthermore, by controlling the ratio of the center thickness T' of the first doublet lens to TTL within the aforementioned range, a compact design of the projection lens module can be achieved without sacrificing optical performance.

[0138] The T' / TTL ratio design in this example of the present application also helps to reduce the manufacturing cost of the entire module. On the one hand, thicker doublet lenses 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 structural design helps to reduce the number and complexity of lenses, thereby reducing processing and assembly costs. In some examples of the present application, 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: 3<(T2+T7) / (T3+T6)<3.8.

[0139] In the example provided in the present application, the center thickness control 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 larger center thicknesses, which can be called thick lenses. The third lens 3 and the sixth lens 6 are two lenses with smaller center thicknesses, which can be called thin lenses. In this example of the present application, it is designed that the sum of the center thickness T2 of the second lens 2 and the center thickness T7 of the seventh lens 7 (T2+T7) and the sum of the center thickness T3 of the third lens 3 and the center 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 center thickness ratio of different lens groups.

[0140] In the example provided in this application, in the first lens assembly, by controlling the ratio of the sum of the center thicknesses of the two thicker lenses (T2 + T7) to the sum of the center thicknesses of the two thinner lenses (T3 + T6), aberrations in the projection lens module can be effectively corrected. For example, thicker lenses typically have a larger optical path difference, which helps 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 ratio control also helps achieve a more uniform spot distribution, improving the clarity and contrast of the projected image, thereby enhancing the visual experience.

[0141] According to the example provided in this application, a compact design of the projection lens module can be achieved without sacrificing optical performance. By combining thicker lenses with thinner lenses, it is possible to reduce unnecessary space occupation while ensuring sufficient optical performance, making the entire projection lens module more compact.

[0142] In some examples of this application, see Figure 4 In the first lens group, the seventh lens 7 is a thick lens, and the center thickness T7 of the seventh lens 7 and the total optical length TTL of the projection lens module satisfy: 5.62%<T7 / TTL<8.12%.

[0143] In the example provided herein, the seventh lens 7 is designed as a thick lens, with its center thickness T7 meeting a specific ratio with the total optical length TTL of the entire projection lens module: 5.62% < T7 / TTL < 8.12%. This optical parameter design is based on a comprehensive consideration of the projection lens module's optical performance, manufacturing process, and cost control.

[0144] As the thickest lens in the first lens assembly, the center thickness T7 of the seventh lens 7 significantly impacts the imaging quality of the projection lens module. By controlling the ratio of T7 to TTL within a reasonable range, we ensure that light is well modulated as it passes through the seventh lens 7, thereby optimizing the optical performance of the entire projection lens module.

[0145] Thick lens design helps increase the effective optical path of the lens, which is particularly effective for correcting advanced aberrations (such as spherical aberration and chromatic aberration). By properly controlling the T7 / TTL value, the imaging quality of the projection lens module can be further improved without increasing the number of lens elements.

[0146] While maintaining optical performance, controlling the center thickness T7 of the seventh lens element 7 within a certain range facilitates a compact projection lens module design (a single thick lens can replace multiple lenses). This thick lens design helps reduce the number of lens elements used, thereby lowering material and assembly costs. This is crucial for large-scale production and cost control.

[0147] In addition, the thicker 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.

[0148] In summary, in this example of the present application, the seventh lens 7 is designed as a thick lens. By controlling the ratio of its central thickness T7 to the total optical length TTL of the projection lens module, multiple technical benefits are achieved, including optimized optical performance, improved module structural compactness, controlled manufacturing process and costs, and enhanced module stability and reliability. These benefits work together to improve the overall performance of the entire projection lens module.

[0149] In some examples of this application, see Figure 4 In the second lens group, the ninth lens 9 is a thick lens, and the center thickness T9 of the ninth lens 9 and the total optical length TTL of the projection lens module satisfy: 6.3%<T9 / TTL<8.8%.

[0150] In the example provided herein, the ninth lens element 9 in the second lens assembly is designed as a thick lens, with its center thickness T9 meeting a specific ratio with the total optical length TTL of the projection lens module: 6.3% < T9 / TTL < 8.8%. This optical parameter design is based on a comprehensive consideration of the projection lens module's performance, structural compactness, and manufacturing feasibility.

[0151] The ninth lens 9, as the thickest lens in the second lens assembly, has a central thickness (T9) that significantly impacts the optical imaging performance of the projection lens module. By maintaining the ratio of T9 to TTL within a reasonable range, light can be well modulated as it passes through the ninth lens 9, thereby optimizing the optical performance of the entire projection lens module.

[0152] The thick lens design helps 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 T9 / TTL ratio, the imaging quality of the projection lens module can be further improved without increasing the number of lens elements.

[0153] By designing the ninth lens 9 as a thick lens and precisely controlling the ratio of its center thickness T9 to TTL, a compact design of the projection lens module can be achieved without sacrificing optical performance. This compact design helps reduce the overall size and weight of the projector.

[0154] Furthermore, the thickness of the ninth lens element 9 not only improves optical performance but also enhances the stability of the projection lens module. Thicker lenses generally have better thermal stability and mechanical strength, making them more resistant to the effects of environmental changes (such as temperature fluctuations and vibration) on module performance.

[0155] In some examples of the present application, 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: 110°<(A3+A4) / 2<130° and 0.75<A3 / A4<1.26.

[0156] In the examples provided herein, the surface shape of the ninth lens element 9 is further controlled, specifically describing the relationship between the angle A3 between the tangent line at the maximum aperture of the object side surface of the ninth lens element 9 and the optical axis, and the angle A4 between the tangent line at the maximum aperture of the image side surface of the ninth lens element 9 and the optical axis. These two angles must meet specific conditions: 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.

[0157] In the example provided herein, by controlling (A3+A4) / 2 between 110° and 130°, the light refraction angles on the object-side and image-side surfaces of the ninth lens element 9 are balanced, reducing aberrations such as spherical aberration and coma. Furthermore, controlling the A3 / A4 ratio between 0.75 and 1.26 ensures a more rational refraction path for light on the surface of the ninth lens element 9, further enhancing aberration correction.

[0158] The control parameters of the ninth lens 9 provided in this example of the present application can optimize its optical performance, which helps improve the optical performance of the projection lens module, making the projected image clearer and more detailed. Furthermore, by properly controlling the above parameters of the ninth lens 9, a compact design of the projection lens module can be achieved without sacrificing optical performance.

[0159] In some examples of this application, see 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 the following relationship: 6<(T9+T10) / T8<9.5.

[0160] In the example provided in this application, the control of the center thickness ratio of lenses of 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 two thicker lenses in the second lens group, while the eighth lens 8 is a 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, namely 6<(T9+T10) / T8<9.5. In other words, the sum of the center thicknesses of the two thick lenses in the second lens group and the sum of the center thickness of one 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.

[0161] In the second lens group, the thicker lenses, namely the ninth and tenth lenses 9 and 10, have a greater optical path difference, which helps to better control the refraction and convergence of light, thereby correcting aberrations in the projection lens module. The thinner lens, namely the eighth lens 8, can provide the necessary light adjustment function without increasing the complexity of the projection lens module.

[0162] According to this example of the present application, a compact design of the projection lens module can be achieved without sacrificing optical performance. Furthermore, the combination of thicker and thinner lenses can reduce unnecessary space occupation while ensuring sufficient optical performance, making the entire projection lens module more compact and lightweight.

[0163] Furthermore, the thicker ninth and tenth lenses 9 and 10 offer greater mechanical strength and thermal stability, better protecting against the effects of environmental fluctuations (such as temperature fluctuations and vibration) on system performance. By carefully controlling the thickness ratio of the different lenses, stress concentration and deformation between the lenses can be reduced, thereby improving the long-term stability and lifespan of the projection lens module.

[0164] In some examples of this application, see Figure 4 , the effective focal length of each lens in the projection lens module satisfies:

[0165] The effective focal length of the first doublet lens is F', 50mm≤F'≤72mm;

[0166] The effective focal length of the third lens 3 is F3, 140mm≤F3≤170m;

[0167] The effective focal length of the second doublet lens is F'', -19mm≤F''≤-15mm;

[0168] The effective focal length of the sixth lens 6 is 35mm≤F6≤50mm;

[0169] The effective focal length of the seventh lens 7 is 20mm≤F7≤30mm;

[0170] The effective focal length of the eighth lens 8 is F8, -11mm≤F8≤-8mm;

[0171] The effective focal length of the ninth lens 9 is F9, 30mm≤F9≤40mm;

[0172] The effective focal length of the tenth lens 10 is F10, 18 mm ≤ F10 ≤ 27 mm.

[0173] The control of the effective focal length of each lens in this example is intended to achieve optimal imaging results for the entire projection lens module by optimizing the optical performance of each lens. By properly controlling the effective focal length of each lens, aberrations in the projection lens module can be more effectively corrected. This optimized aberration correction is crucial for improving the clarity and contrast of the projected image.

[0174] In the example provided herein, the effective focal length F3 of the third lens element 3 ranges from 140mm to 170mm, a relatively wide focal length range. In a zoom projection lens module, the wide focal length range of the third lens element 3 plays a key role in achieving the module's zoom function. As a positive focal length lens, the flexible adjustment of the focal length of the third lens element 3 helps the projection lens module smoothly transition between long, medium, and short focal lengths.

[0175] In the example provided herein, the effective focal length F'' of the second doublet lens ranges from -19mm to -15mm, a range of negative optical power. The negative optical power doublet lens can be used to correct chromatic aberration and balance light during the module's zooming process. Furthermore, by pairing it with the third lens 3, which has positive optical power (the two can move synchronously along the optical axis), precise focal length adjustment is achieved. In other words, the second doublet lens acts as a negative optical power element, working in conjunction with the positive optical power of the third lens 3 to achieve the zoom function of the projection lens module.

[0176] By precisely controlling the focal length range of the third lens 3 and the second doublet lens, the optical performance of the entire projection lens module can be optimized at different focal lengths. For example, combining a large positive focal power (such as the third lens) with an appropriate negative focal power (such as the second doublet lens) helps correct various aberrations and improve image clarity and contrast. Furthermore, this focal length design facilitates miniaturization and lightweighting of the lens module while maintaining excellent optical performance.

[0177] During zooming, the third lens 3 and the second doublet lens must move synchronously along the optical axis while maintaining a constant relative spacing. This design mechanism requires precise matching of the lens focal length ranges to ensure smooth zooming and consistent image quality.

[0178] 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 properly setting the focal length range of these two lenses, a wider focal length coverage can be achieved without increasing the lens size, thus meeting the space constraints of micro-projection equipment.

[0179] In addition, by carefully designing the effective focal length range of other lenses, the projection lens module of this application has achieved significant technical effects in chromatic aberration correction, imaging quality improvement, and light path optimization.

[0180] In some examples of the present application, each lens in the projection lens module is a spherical lens.

[0181] In one example, all lenses in the projection lens are glass spherical lenses, that is, the first lens 1 to the tenth lens 10 are all glass lenses.

[0182] The spherical lens design meets the high-quality imaging requirements of projection lenses while offering relatively low manufacturing costs, helping to reduce the overall production cost of projection lens modules. Spherical lenses offer excellent optical performance, reducing light scattering and absorption, and improving image clarity and contrast. Furthermore, their low manufacturing cost contributes to lowering the overall cost of lens production.

[0183] Glass materials have high thermal and chemical stability, and can maintain stable optical performance under different environmental conditions. This helps enhance the stability of the projection lens module and improve the reliability and service life of the product.

[0184] In general, glass spherical lenses have a simple design and are easy to combine with other optical elements.

[0185] In some examples of this application, see Figure 4 The projection lens module further includes a galvanometer 12 and a prism 13 located on the object side of the tenth lens 10 and arranged in sequence.

[0186] The galvanometer mirror 12 and the prism 13 , together with the first lens 1 to the tenth lens 10 , constitute the projection lens of the projection lens module of the present application.

[0187] Whether the galvanometer 12 is provided or not depends on specific application requirements.

[0188] The prism 13 is 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.

[0189] The prism 13 may be designed as a total internal reflection prism (TIR prism).

[0190] In some examples of this application, see 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 .

[0191] The display unit 14 , as a component of the projection lens module, is responsible for generating and providing light for projection imaging to the projection lens.

[0192] The display unit 14 is, for example, a high-resolution display device such as LCD, DLP or LCOS, which can generate high-quality image signals.

[0193] The glass plate 15 is positioned between the display unit 14 and the prism 13 to ensure that light emitted from the display unit 14 efficiently passes through the subsequent prisms and lens assembly, ultimately forming a high-quality projected image. The glass plate 15, with its high light transmittance and low reflectivity, reduces light loss and interference during transmission, thereby improving the brightness and contrast of the projected image.

[0194] 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.

[0195] In the example provided in this application, the projection lens module includes not only two lens groups and an aperture 11, but also a galvanometer 12, a prism 13, a glass plate 15, and a display unit 14. Furthermore, the application specifies a range for the ratio of the total optical length (TTL) of the projection lens module to the maximum aperture (D1) of the lens (2.9 < TTL / D1 < 3.7). The following is a detailed analysis of this design.

[0196] By precisely controlling the TTL / D1 ratio range, it is possible to achieve a compact design of the projection lens module while maintaining adequate optical performance. This ratio setting ensures that the projection lens module has a sufficiently long working distance and imaging range without affecting the projector's portability and usage scenarios due to excessive size and weight.

[0197] In some examples of this application, see Figure 4 As shown in Table 2, the focal length of the projection lens module is 23.5mm~35.1mm, the throw 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.

[0198] Specifically, see Table 2, which shows Figure 4 Provides optical parameters of the projection lens module.

[0199] Table 2

[0200]

[0201] According to this example of the present application, the focal length range of the projection lens module is between 23.5mm and 35.1mm, so that the projection lens module can cover a wider projection distance and screen size to meet the needs of different application scenarios.

[0202] The projection ratio TR of the projection lens module is between 4.5 and 6.7, which means that a larger picture size can be achieved within a shorter projection distance, which is particularly important for places with limited space.

[0203] The projection lens module has a field of view of 4.7° to 7.3°, which isn't particularly wide, but provides a range of viewing angles while maintaining image quality. This field of view meets the requirements of commercial micro-projection equipment.

[0204] 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.

[0205] The image size is between 5.3mm and 6.6mm, ensuring the clarity and fineness of the projected image.

[0206] The total optical length TTL of the projection lens module provided in the embodiment of the present application is only 80 mm, and the maximum effective aperture D1 is 24 mm, which makes the overall structure of the projection lens module compact and easy to integrate into the micro projector.

[0207] Through precise optical design and parameter control, the projection lens module can achieve high-quality imaging effects and meet users' high requirements for projection image quality.

[0208] Table 2 shows the optical parameter design in one state (eg, initial state). It should be noted that the projection lens module provided in the embodiments of the present application includes but is not limited to the optical design in Table 2. For other designs, please refer to Examples 1 to 3 below.

[0209] See also Figure 5 , Figure 5 The distortion diagram of the projection lens module provided in the above example of this application has an absolute value of distortion less than 0.7%.

[0210] See also Figure 6 , Figure 6 The MTF diagram of the projection lens module provided in the above example of this application shows that the MTF is >0.5 at 93lp / mm.

[0211] According to another embodiment of the present application, a micro-projection device is provided, which includes a housing and the projection lens module as described above.

[0212] The micro-projection device provided in the embodiment of the present application can be applied to commercial micro-projection devices.

[0213] 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 about by the technical solutions of the above embodiments, which will not be described in detail here.

[0214] The projection lens module of the present application is described below through Examples 1 to 3, wherein Example 1 is the long-focus state of the projection lens module, Example 2 is the medium-focus state of the projection lens module, and Example 3 is the short-focus state of the projection lens module.

[0215] Example 1

[0216] See also Figure 7 The projection lens module provided in Example 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 project the light emitted by the display unit 14 into an image;

[0217] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0218] The first lens group includes a first doublet, a third lens 3, a second doublet, a sixth lens 6, and a seventh lens 7 arranged along the optical axis, the first doublet having positive optical power, the third lens 3, the sixth lens 6, and the seventh lens 7 all having positive optical power, and the second doublet having negative optical power; wherein the first doublet is formed by cementing a first lens 1 and a second lens 2, the first lens 1 having negative optical power, and the second lens 2 having positive optical power; and the second doublet is formed by cementing a fourth lens 4 and a fifth lens 5, the fourth lens 4 having negative optical power, and the fifth lens 5 having positive optical power;

[0219] The third lens 3 and the second doublet lens form a linked zoom lens group and are configured so that the two lenses 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;

[0220] 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 power;

[0221] The first lens 1 to the tenth lens 10 are all glass spherical lenses;

[0222] The aperture 11 is located between the seventh lens 7 and the eighth lens 8;

[0223] The projection lens further includes a galvanometer mirror 12 and a prism 13 , which are sequentially disposed between the tenth lens 10 and the glass plate 15 .

[0224] The projection lens module provided in this embodiment 1 is in telephoto mode.

[0225] See also Figure 7 , Figure 7 The optical parameters of the projection lens module are shown in Table 3 below.

[0226] Table 3

[0227]

[0228] The projection lens module provided in this embodiment 1 has the following optical properties: Figures 8 to 11 As shown: Figure 8 is a point diagram diagram. Figure 9 is the MTF curve graph, Figure 10 It is the field curvature and distortion diagram, Figure 11 This is the vertical axis chromatic aberration diagram.

[0229] 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 4 μm.

[0230] See also Figure 9 The projection lens module provided in this embodiment 1 has an MTF greater than 0.5 at 93 lp / mm.

[0231] See also Figure 10 In the projection lens module provided in this embodiment 1, the maximum distortion occurs in 1 field of view, and the absolute value is less than 0.7%.

[0232] See also Figure 11 The projection lens module provided in this embodiment 1 has a maximum chromatic aberration value of less than 2 μm.

[0233] Example 2

[0234] See also Figure 12 The projection lens module provided in Example 2 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 project the light emitted by the display unit 14 into an image;

[0235] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0236] The first lens group includes a first doublet, a third lens 3, a second doublet, a sixth lens 6, and a seventh lens 7 arranged along the optical axis, the first doublet having positive optical power, the third lens 3, the sixth lens 6, and the seventh lens 7 all having positive optical power, and the second doublet having negative optical power; wherein the first doublet is formed by cementing a first lens 1 and a second lens 2, the first lens 1 having negative optical power, and the second lens 2 having positive optical power; and the second doublet is formed by cementing a fourth lens 4 and a fifth lens 5, the fourth lens 4 having negative optical power, and the fifth lens 5 having positive optical power;

[0237] The third lens 3 and the second doublet lens form a linked zoom lens group and are configured so that the two lenses 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;

[0238] 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 power;

[0239] The first lens 1 to the tenth lens 10 are all glass spherical lenses;

[0240] The aperture 11 is located between the seventh lens 7 and the eighth lens 8;

[0241] The projection lens further includes a galvanometer mirror 12 and a prism 13 , which are sequentially disposed between the tenth lens 10 and the glass plate 15 .

[0242] The projection lens module provided in Example 2 is in the mid-focus mode.

[0243] See also Figure 12 , Figure 12 The optical parameters of the projection lens module shown are shown in Table 4 below.

[0244] Table 4

[0245]

[0246] The projection lens module provided in this embodiment 2 has the following optical properties: Figures 13 to 16 As shown: Figure 13 is a point diagram diagram. Figure 14 is the MTF curve graph, Figure 15 It is the field curvature and distortion diagram, Figure 16 This is a diagram of vertical chromatic aberration.

[0247] See also Figure 13 In the projection lens module provided in this embodiment 2, the maximum value of the image point in the point diagram is less than 4 μm.

[0248] See also Figure 14 The projection lens module provided in this embodiment 2 has an MTF greater than 0.4 at 93 lp / mm.

[0249] See also Figure 15 In the projection lens module provided in this embodiment 2, the maximum distortion occurs in 1 field of view, and the absolute value is less than 0.15%.

[0250] See also Figure 16 The projection lens module provided in this embodiment 2 has a maximum chromatic aberration value of less than 2 μm.

[0251] Example 3

[0252] See also Figure 17 The projection lens module provided in Example 3 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 project the light emitted by the display unit 14 into an image;

[0253] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0254] The first lens group includes a first doublet, a third lens 3, a second doublet, a sixth lens 6, and a seventh lens 7 arranged along the optical axis, the first doublet having positive optical power, the third lens 3, the sixth lens 6, and the seventh lens 7 all having positive optical power, and the second doublet having negative optical power; wherein the first doublet is formed by cementing a first lens 1 and a second lens 2, the first lens 1 having negative optical power, and the second lens 2 having positive optical power; and the second doublet is formed by cementing a fourth lens 4 and a fifth lens 5, the fourth lens 4 having negative optical power, and the fifth lens 5 having positive optical power;

[0255] The third lens 3 and the second doublet lens form a linked zoom lens group and are configured so that the two lenses 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;

[0256] 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 power;

[0257] The first lens 1 to the tenth lens 10 are all glass spherical lenses;

[0258] The aperture 11 is located between the seventh lens 7 and the eighth lens 8;

[0259] The projection lens further includes a galvanometer mirror 12 and a prism 13 , which are sequentially disposed between the tenth lens 10 and the glass plate 15 .

[0260] The projection lens module provided in this embodiment 3 is in short-focus mode.

[0261] See also Figure 17 , Figure 17 The optical parameters of the projection lens module are shown in Table 5 below.

[0262] Table 5

[0263]

[0264] The projection lens module provided in this embodiment 3 has the following optical properties: Figures 18 to 21 As shown: Figure 18 is a point diagram diagram. Figure 19 is the MTF curve graph, Figure 20 It is the field curvature and distortion diagram, Figure 21 This is a diagram of vertical chromatic aberration.

[0265] See also Figure 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.

[0266] See also Figure 19 The projection lens module provided in this embodiment 3 has an MTF greater than 0.5 at 93 lp / mm.

[0267] See also Figure 20 In the projection lens module provided in this embodiment 3, the maximum distortion occurs in 1 field of view, and the absolute value is less than 0.7%.

[0268] See also Figure 21 The projection lens module provided in this embodiment 3 has a maximum chromatic aberration value of less than 2 μm.

[0269] 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.

[0270] 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 for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples 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 projection lens module has a projection ratio TR of 4.5 to 6.7, and the projection lens module comprises a first lens group, a diaphragm (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) 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) 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 the two remains constant, so that the projection lens module can achieve zooming within a predetermined focal length range; 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; The effective focal length of the second doublet lens is F'', -19mm≤F''≤-15mm; 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, and A3 and A4 satisfy the following: 110°<(A3+A4) / 2<130° and 0.75<A3 / A4<1.

26.

2. The projection lens module according to claim 1, wherein: 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 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, wherein: 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 2, wherein: The first doublet lens is composed of a first lens (1) and a second lens (2) glued 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).

5. The projection lens module according to claim 4, wherein: The center thickness T' of the first doublet lens and the total optical length TTL of the projection lens module satisfy the following: 5.5%<T' / TTL<7.9%.

6. The projection lens module according to claim 4, wherein: 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.

7. The projection lens module according to claim 1 or 6, wherein: In the first lens group, the center 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%.

8. The projection lens module according to claim 1, wherein: In the second lens group, the center 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%.

9. The projection lens module according to claim 1 or 8, wherein: 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 the following relationship: 6<(T9+T10) / T8<9.

5.

10. The projection lens module according to claim 1, wherein: The effective focal length of each lens in the projection lens module satisfies: The effective focal length of the first doublet 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 sixth lens (6) is 35mm≤F6≤50mm; The effective focal length of the seventh lens (7) is 20mm≤F7≤30mm; 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, 30mm≤F9≤40mm; 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.

11. The projection lens module according to claim 10, wherein: The projection lens module further includes 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 the following: 2.9<TTL / D1<3.

7.

12. The projection lens module according to claim 1, wherein: The focal length of the projection lens module is 23.5mm~35.1mm, 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.

13. A micro-projection device, characterized in that: include: shell; and The projection lens module according to any one of claims 1 to 12.

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