Projection lens module and projection equipment

Abstract

The embodiment of the invention provides a projection lens module and projection equipment. The projection lens module comprises a first lens group, a diaphragm and a second lens group which are arranged along an optical axis; the first lens group comprises a first lens, a second lens, a third lens, a fourth lens and a doublet lens which are arranged in sequence, the first lens, the second lens and the third lens have negative focal power, and the fourth lens and the doublet lens have positive focal power; the second lens group comprises a triplet lens and a tenth lens, the triplet lens has negative focal power, and the tenth lens has positive focal power; the diaphragm is located between the doublet lens and the triplet lens, the interval between the diaphragm and the doublet lens is L1, the interval between the diaphragm and the triplet lens is L2, and L1 and L2 satisfy 3.3 lt; l1 / L2lt; 4; the first lens is a plastic aspheric lens, the tenth lens is a glass aspheric lens, and the refractive index N1 of the first lens and the refractive index N10 of the tenth lens meet the condition that N1 / N10 is larger than 1.03 and smaller than 1.1.

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 projection device. Background Art

[0002] Currently, projection equipment is increasingly used in scenarios such as home entertainment and office presentations. Traditional projectors typically use telephoto or standard focal length projection lenses. These lenses require a longer projection distance and have strict requirements for the installation location, such as:

[0003] Large space occupation: Conventional projector, see Figure 1 , it needs to be placed far away from the projection wall (usually more than 2m), resulting in reduced space utilization in the living room or conference room, especially in small-sized environments.

[0004] Occlusion problem: Due to the limitation of projection angle, there must be no obstructions (such as furniture, decorations, etc.) between the projector and the projection wall, otherwise it will affect the integrity of the projection image and affect the user experience.

[0005] Complex optical design: Existing short-throw projection lenses usually use a reflective structure (such as a free-form mirror or a reflective bowl) to shorten the projection distance. However, this design not only increases the size and weight of the system, but also increases the manufacturing cost and difficulty of assembly and adjustment.

[0006] To solve the above problems, some attempts have been made in the prior art to adopt a refractive short-throw projection lens design, but the prior art still has the following deficiencies:

[0007] (1) It is difficult to balance the throw ratio (TR) and offset: In the design of short-focus lenses, reducing the throw ratio (TR) usually leads to a decrease in the offset, making the projected image closer to the projector body and more easily blocked by the body.

[0008] (2) Limited optical performance: When existing short-focus lenses achieve a small throw ratio (such as TR ≤ 0.6), they often need to increase the number of lenses (such as more than 12) or adopt many complex aspheric designs, which leads to increased system costs and difficulty in correcting aberrations (such as distortion, chromatic aberration, etc.).

[0009] (3) It is difficult to balance volume and image quality: Although some short-focus lenses are small in size, the image uniformity is poor and the MTF (modulation transfer function) of the edge field of view decreases significantly, affecting the display effect.

[0010] Therefore, there is an urgent need for a new type of projection lens module that can reduce the number of lenses, lower system complexity, and have excellent optical performance while ensuring a small throw ratio and large offset. Summary of the Invention

[0011] The purpose of this application is to provide a new technical solution for a projection lens module and a projection device.

[0012] In a first aspect, an embodiment of the present application provides a projection lens module, wherein the projection lens module includes:

[0013] a first lens group comprising a first lens, a second lens, a third lens, a fourth lens, and a doublet lens, arranged in sequence along the optical axis, wherein the first lens, the second lens, and the third lens all have negative optical power, and the fourth lens and the doublet lens all have positive optical power;

[0014] a second lens group comprising a triplet lens and a tenth lens arranged along the optical axis, wherein the triplet lens has a negative optical power and the tenth lens has a positive optical power;

[0015] The aperture is located between the doublet lens and the triplet lens, the interval between the aperture and the doublet lens is L1, the interval between the aperture and the triplet lens is L2, and the interval between L1 and L2 satisfies: 3.3 <L1 / L2<4;

[0016] The first lens is a plastic aspheric lens, the tenth lens is a glass aspheric lens, and the refractive index N1 of the first lens and the refractive index N10 of the tenth lens satisfy the following relationship: 1.03<N1 / N10<1.1.

[0017] Optionally, the center thickness T' of the triplet lens satisfies 8.5%≤T' / TTL≤10%; wherein TTL is the total optical length of the projection lens module.

[0018] Optionally, the triplet lens is composed of a seventh lens, an eighth lens, and a ninth lens glued together in sequence, wherein:

[0019] The seventh lens element and the ninth lens element both have positive refractive power;

[0020] The eighth lens has negative optical power;

[0021] The refractive index of either the seventh lens or the ninth lens is lower than that of the eighth lens.

[0022] Optionally, the refractive indexes of the seventh lens and the ninth lens are N1 and N2 respectively, the refractive index of the eighth lens is N3, and the triplet lens satisfies: 1.2 <N3 / (N1+N2)<1.3。

[0023] Optionally, the triple cemented lens satisfies 5 < (T5 + T6) / T7 < 6, where: T5 is the central thickness of the seventh lens, T6 is the central thickness of the eighth lens, and T7 is the central thickness of the ninth lens.

[0024] Optionally, the doublet lens is composed of a fifth lens and a sixth lens cemented together, where:

[0025] The fifth lens and the sixth lens have opposite optical powers. One of the fifth lens and the sixth lens has a positive optical power, and the other has a negative optical power, and the refractive index of the lens with positive optical power is higher than that of the lens with negative optical power.

[0026] Optionally, the fifth lens has a positive optical power and a refractive index of N5, the sixth lens has a negative optical power and a refractive index of N6, and N5 and N6 satisfy: 1.03 < N5 / N6 < 1.1.

[0027] Optionally, the first lens group satisfies: 0.95 < T3 / (T1 + T2) < 1.3, where: T1 is the central thickness of the first lens, T2 is the central thickness of the second lens, and T3 is the central thickness of the third lens.

[0028] Optionally, the central thickness T1 of the first lens satisfies 3.3% ≤ T1 / TTL ≤ 3.7%;

[0029] The central thickness T2 of the second lens satisfies 1.5% ≤ T2 / TTL ≤ 1.8%;

[0030] where, TTL is the total optical length of the projection lens module.

[0031] Optionally, the sagittal height of the surface of the second lens away from the aperture stop at the maximum aperture is S1, and the sagittal height of the surface of the second lens close to the aperture stop at the maximum aperture is S2, and they satisfy: 3.5 < S2 / S1 < 4.5.

[0032] Optionally, the angle between the tangent of the surface of the second lens away from the aperture stop and the optical axis at the maximum aperture is A1, and the angle between the tangent of the surface of the second lens close to the aperture stop and the optical axis at the maximum aperture is A2, and they satisfy: 40° < A1 - A2 < 50°, and 1.8 < A1 / A2 < 2.3.

[0033] Optionally, the angle between the tangent of the surface of the third lens away from the aperture stop and the optical axis at the maximum aperture is A3, and the angle between the tangent of the surface of the third lens close to the aperture stop and the optical axis at the maximum aperture is A4, and they satisfy: 40° < A3 - A4 < 60°, and 1.6 < A3 / A4 < 2.1.

[0034] Optionally, the projection lens module further includes a prism, a glass plate, and a display unit that are located on a side of the tenth lens away from the aperture and are sequentially arranged;

[0035] 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 satisfies the following: 1.5<TTL / D1<1.9.

[0036] Optionally, the effective focal lengths of the lenses in the projection lens are:

[0037] The effective focal length of the first lens is F1, -32mm≤F1≤-24mm;

[0038] The effective focal length of the second lens is F2, -19mm≤F2≤-14mm;

[0039] The effective focal length of the third lens is F3, -19mm≤F3≤-14mm;

[0040] The effective focal length of the fourth lens is F4, 25mm≤F4≤36mm;

[0041] The effective focal length of the doublet lens is F', 17mm≤F'≤25mm;

[0042] The effective focal length of the triplet lens is F", -80mm≤F"≤-55mm;

[0043] The effective focal length of the tenth lens is F10, 9mm≤F10≤14mm;

[0044] The second lens to the ninth lens are glass spherical lenses.

[0045] Optionally, the focal length of the projection lens module is 2.83mm, the projection ratio TR is 0.5, the relative aperture is 1 / 1.699, the offset is 140%, the pixel size is 5.4μm, the field of view angle is 55°~59°, the image plane size is 8.5mm~9.1mm, and the operating band is 455nm~630nm.

[0046] In a second aspect, an embodiment of the present application provides a projection device, comprising:

[0047] casing; and

[0048] The projection lens module as described in the second aspect.

[0049] The beneficial effects of this application are:

[0050] The projection lens module provided by the embodiments of the present application adopts a specially designed lens combination method. The first lens group adopts a "negative-negative-negative-positive-double cemented (positive)" structure, and the second lens group adopts a "triple cemented (negative)-positive" structure. This way of power distribution realizes reasonable light refraction and focusing, effectively improving the imaging quality. Among them, the design of the three negative lenses in the first lens group not only simplifies the optical path structure, but also effectively corrects the field curvature and distortion, improving the flatness of the picture. The triple cemented lens in the second lens group compensates for the axial chromatic aberration through its complex refraction characteristics, further improving the color reproduction and imaging clarity. Thanks to the above optimized power distribution, the projection lens module of the present application can maintain excellent imaging quality within the full field of view (55° to 59°). Especially for the distortion problem common in short-focus projection systems, the present application effectively controls the distortion at a low level (such as within 1.5%), significantly better than similar products.

[0051] The present application adopts a compact optical architecture. By reasonably arranging the positions of each lens and the setting of the aperture (located between the double cemented lens and the triple cemented lens, and satisfying the interval ratio relationship of 3.3 < L1 / L2 < 4), the overall optical length is effectively shortened. The overall optical length of the entire projection lens module can be controlled within 78 mm, for example, and the maximum aperture does not exceed 47 mm, greatly reducing the volume and weight. This compact design not only reduces the production cost, but also makes the projection lens module more suitable for application scenarios with limited space, such as home projectors, portable projection devices, etc.

[0052] The projection lens module of the present application achieves the design goals of a small projection ratio (TR = 0.5) and a large offset (140%), enabling the projection screen to obtain a large size within a short projection distance while maintaining the clarity and brightness of the picture. There is no need to use a complex reflector bowl structure, reducing the processing difficulty and cost of the product and improving the overall performance and reliability of the lens.

[0053] In addition, the first lens adopts a plastic aspheric lens, which has the advantages of low cost, easy processing, and light weight; the tenth lens adopts a glass aspheric lens, ensuring high imaging quality and stability. By reasonably controlling the refractive index ratio of the first lens and the tenth lens (1.03 < N1 / N10 < 1.1), the optical performance of the lens is further improved, and good matching between lenses of different materials is ensured.

[0054] 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

[0055] 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.

[0056] Figure 1 This is a schematic diagram of the installation and projection of a conventional projector;

[0057] Figure 2 This is a projection principle diagram of a projection lens module used in a projection device according to an embodiment of the present application;

[0058] Figure 3 A schematic diagram of the optical architecture of a projection lens module provided in an embodiment of the present application;

[0059] Figure 4 A schematic diagram of the partial structure of the second lens provided in an embodiment of the present application;

[0060] Figure 5 A schematic diagram of the partial structure of the third lens provided in an embodiment of the present application;

[0061] Figure 6 The structure and optical path diagram of the projection lens module provided in Example 1 of the present application;

[0062] Figure 7 The structure and optical path diagram of the projection lens module provided in Example 2 of the present application;

[0063] Figure 8 The structure and optical path diagram of the projection lens module provided in Example 3 of the present application;

[0064] Figure 9 The structure and optical path diagram of the projection lens module provided in Example 4 of the present application;

[0065] Figure 10 The structure and optical path diagram of the projection lens module provided in Example 5 of the present application;

[0066] Figure 11 A distortion diagram of the projection lens module provided in an embodiment of the present application;

[0067] Figure 12 This is the MTF diagram of the projection lens module provided in an embodiment of the present application.

[0068] Description of reference numerals:

[0069] 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. Prism; 13. Display unit; 14. Glass plate. DETAILED DESCRIPTION

[0070] 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.

[0071] The following description of at least one exemplary embodiment is merely illustrative and in no way restricts the present application, its application, or its use.

[0072] Techniques and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques and devices should be regarded as part of the specification.

[0073] In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as limitations. Thus, other examples of the exemplary embodiments may have different values.

[0074] 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.

[0075] The projection lens module and the projection device provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0076] According to an embodiment of the present application, a projection lens module is provided. Referring to Figure 3 , the projection lens module includes a first lens group, an aperture stop, and a second lens group arranged in sequence along the same optical axis. The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a doublet lens arranged in sequence along the optical axis. Among them, the first lens 1, the second lens 2, and the third lens 3 all have negative optical power, and the fourth lens 4 and the doublet lens both have positive optical power. The second lens group includes a triplet lens and a tenth lens 10 arranged along the optical axis. Among them, the triplet lens has negative optical power, and the tenth lens 10 has positive optical power. The aperture stop 11 is located between the doublet lens and the triplet lens. The distance between the aperture stop 11 and the doublet lens is L1, and the distance between the aperture stop 11 and the triplet lens is L2. And L1 and L2 satisfy: 3.3 < L1 / L2 < 4. The first lens 1 is a plastic aspheric lens, and the tenth lens 10 is a glass aspheric lens. And the refractive index N1 of the first lens 1 and the refractive index N10 of the tenth lens 10 satisfy: 1.03 < N1 / N10 < 1.1.

[0077] In the current home projector market, the desktop projection form is a common projection method. However, referring to Figure 1 ,This form of projection has two significant pain points, which restrict its user experience and market promotion.

[0078] One of the pain points: space occupied.

[0079] See also Figure 1 , traditional desktop projectors usually require a large installation space to ensure the integrity and clarity of the projected image. This requirement strictly limits the placement of projectors in living rooms, which not only takes up space resources but also may affect the overall layout and aesthetics of the living room. For users with smaller living spaces, this pain point is particularly prominent, as they often cannot install or use projectors (i.e., due to lack of space). Figure 1 ).

[0080] Pain point 2: No obstructions are allowed.

[0081] Another significant pain point is that traditional projectors cannot tolerate obstructions in the projection light path. Any obstruction can cause missing or distorted images, severely impacting the viewing experience. This limitation necessitates avoiding placing objects in the projection path when using a projector. This not only creates significant inconvenience for users but also limits the projector's flexibility and application scenarios.

[0082] In order to solve the above two pain points, this application proposes an optical design of a short-throw projection lens module. This short-throw projection technology has the characteristics of small projection ratio and large offset, which can achieve a larger projection image within a shorter projection distance. Figure 2 , thereby effectively reducing the projector's demand for installation space.

[0083] Specifically, the projection lens module design provided by this application achieves excellent performance with a throw ratio of 0.5 and an offset of 140%. This optical design not only significantly reduces the installation space required for the projection device (which houses the projection lens module of this application), allowing users to use the projection device in a smaller space, but also, by increasing the offset value, allows the projected image to be further away from the projection device itself, effectively preventing the projection device itself from obstructing the projected image.

[0084] The projection lens module provided in the embodiments of the present application is described in detail below.

[0085] The projection lens module provided in the embodiment of the present application mainly includes optical components such as a projection lens and a display unit 13. The projection lens is designed to be located on the light path of the display unit 13. Figure 3The projection lens is responsible for receiving the light emitted from the display unit 13 (these light are dedicated to projection display), and modulating and focusing it. After this series of optical operations, the light is projected onto the imaging surface to form a clear projection image.

[0086] See also Figure 3 The projection lens provided in the embodiment of the present application includes two lens groups: a first lens group and a second lens group. Figure 3 Compared with the second lens group, it is further away from the display unit 13. Figure 3 The second lens group (located on the right side) is arranged close to the display unit 13. In addition, an aperture 11 is provided between the two lens groups to optimize the transmission of light and the imaging effect.

[0087] The first lens group and the second lens group are described in detail below.

[0088] The first lens group provided in the embodiment of the present application comprises, for example, six lenses in total. Figure 3 The first lens group is designed to consist of a first lens 1, a second lens 2 and a third lens 3 with negative optical focal length, a fourth lens 4 with positive optical focal length and a doublet lens.

[0089] Specifically, the first lens group comprises three lenses with negative optical power, namely, the first lens 1, the second lens 2, and the third lens 3, arranged sequentially along the optical axis. The combination of these three negative lenses not only expands the field of view but also effectively corrects field curvature. The characteristic of negative lenses lies in their ability to diverge light. By properly designing optical parameters such as curvature and center thickness, the light passing through these three lenses can play a significant role in correcting field curvature. Following these three negative lenses, the first lens group also includes a fourth lens 4 with positive optical power. The addition of this positive lens effectively balances the negative power generated by the preceding three negative lenses, resulting in a more balanced optical power distribution across the entire first lens group. This combination of positive and negative lenses helps reduce aberrations and improve image quality. The positive power of the doublet lens, the final element in the first lens group, not only further balances the optical power distribution but also effectively corrects chromatic aberration through its unique cemented structure.

[0090] By employing three negative-power lenses as the initial components of the first lens group, the optical design of this application can expand the field of view to 55° to 59°. This wide field of view design enables the projection lens module to be applied to a wider range of projection scenarios, meeting the diverse needs of users. Furthermore, the introduction of positive-power lenses and doublets effectively controls distortion and chromatic aberration.

[0091] The projection lens module provided in this embodiment has a second lens group, a key component of the entire projection lens, that works in conjunction with the first lens group to achieve excellent optical performance. The following is a detailed description of the technical effects of the second lens group and its related designs.

[0092] The second lens group, primarily composed of a triplet lens and a tenth lens element 10, employs a unique "triplet (negative)-positive" structural design. This design fully utilizes the complex refractive properties of the triplet lens, effectively correcting aberrations through its negative focal length, thereby improving image quality.

[0093] The tenth lens 10, as a positive power lens, further enhances the projection imaging capability of the projection lens. It not only balances the negative power of the triplet lens, but also improves the light convergence effect, making the projected image clearer and brighter.

[0094] By adopting the above-mentioned structural design, the projection lens module provided in the embodiment of the present application can maintain excellent imaging quality across the entire field of view (55° to 59°). A clear image is presented in both the center and the edges of the image. This excellent full-field imaging quality is due to the precise correction of aberrations by the second lens group and the enhanced light focusing capability of the tenth lens 10.

[0095] Furthermore, the design of the second lens assembly not only focuses on improving optical performance but also fully considers the module's compactness. By carefully planning the position and shape of each lens, the overall volume of the second lens assembly is effectively controlled. This compact design not only reduces production costs but also makes the projection lens module more suitable for space-constrained applications. It also ensures that the projection lens module maintains high performance while offering a wider range of applicability.

[0096] In the projection lens module provided in the embodiment of the present application, the aperture 11 is positioned between the doublet lens and the triplet lens. This design is based on comprehensive considerations of the light propagation path, aberration correction, and overall structural layout.

[0097] The aperture 11 is a key optical element in the projection lens module, and its position plays a crucial role in aberration correction. Positioning it between the doublet and triplet effectively balances the aberration correction capabilities of the first lens group (including all lenses preceding the doublet) and the second lens group (including all lenses following the triplet).

[0098] This position setting helps the first lens group and the second lens group work together. By each taking part of the aberration correction task, they jointly achieve excellent imaging performance within the full field of view. Specifically, the doublet lens, as an important part of the first lens group, mainly corrects high-order aberrations such as astigmatism; while the triplet lens effectively corrects various aberrations such as spherical aberration and chromatic aberration through its complex refraction characteristics. The aperture stop 11 is just located between the two, playing a crucial role in connecting the above and the below.

[0099] The aperture stop 11 is not only a light-transmitting aperture, but it also limits the light beam entering the projection lens. By controlling the aperture size of the aperture stop, it can ensure that only light within a specific angle and range can participate in imaging, thus effectively reducing the generation of stray light and ghost images. This limitation of the light beam is of great significance for improving the clarity and contrast of the image. It can ensure that the imaging light propagates more concentratedly and orderly to the imaging surface, avoiding image blurring and distortion caused by stray light and ghost images.

[0100] In addition, the position of the aperture stop 11 also affects the overall structural layout of the projection lens. Placing it between the doublet lens and the triplet lens helps to achieve a compact design of the projection lens module.

[0101] In summary, the aperture stop 11 is set at the position between the doublet lens and the triplet lens. It not only achieves the balance and optimization of aberration correction, but also improves the imaging quality and realizes a compact design, providing support for the development of the projection lens module in the direction of high performance and low cost.

[0102] In the projection lens module provided in the embodiment of the present application, the aperture stop 11 is placed between the doublet lens and the triplet lens. The interval L1 between the aperture stop 11 and the doublet lens, and the interval L2 between the aperture stop 11 and the triplet lens satisfy a specific proportional relationship: 3.3 < L1 / L2 < 4. This design not only effectively balances the aberration correction capabilities of the first lens group and the second lens group, but also reduces the generation of stray light and ghost images by restricting the propagation path of the light beam, thereby significantly improving the clarity and contrast of the image.

[0103] This application adopts a compact optical architecture. By reasonably arranging the positions of each lens and setting the aperture stop 11 (located between the doublet lens and the triplet lens and satisfying the interval ratio relationship of 3.3 < L1 / L2 < 4), the overall optical length is effectively shortened. The overall optical length of the entire projection lens module can be controlled within 78 mm, for example, and the maximum aperture does not exceed 47 mm, greatly reducing the volume and weight. This compact design not only reduces the production cost but also makes the projection lens module more suitable for application scenarios with limited space, such as home projectors, portable projection devices, etc.

[0104] In the projection lens module provided by the embodiment of this application, the first lens 1 uses a plastic aspherical lens, and the tenth lens 10 uses a glass aspherical lens. The selection of these two materials not only considers cost-effectiveness but also fully takes into account their respective optical characteristics. Plastic aspherical lenses have the advantages of low cost, light weight, and easy processing and molding. Glass aspherical lenses, on the other hand, have excellent optical performance and thermal stability, ensuring that the projection lens can still maintain stable imaging quality during long-term use.

[0105] More importantly, the refractive index N1 of the first lens 1 and the refractive index N10 of the tenth lens 10 satisfy a specific ratio relationship, that is, 1.03 < N1 / N10 < 1.1. This design not only helps to further balance the propagation of light and the correction of aberration but also improves the overall imaging performance of the projection lens module by optimizing the optical path structure.

[0106] The projection lens module of the embodiment of this application achieves the design goals of a small throw ratio (TR = 0.5) and a large offset (140%), enabling the projection screen to obtain a large size within a short projection distance while maintaining the clarity and brightness of the screen. There is no need to use a complex reflector bowl structure, reducing the processing difficulty and cost of the product and improving the overall performance and reliability of the lens.

[0107] The overall optical length of the projection lens module of the embodiment of this application can be controlled within 78 mm, and the maximum aperture does not exceed 47 mm. This design reduces the volume while achieving TR = 0.5 and short-focus performance, and is more suitable for application scenarios with limited space.

[0108] The projection lens module provided by the embodiment of this application,凭借其卓越的光学性能和紧凑的设计,适用于各种家用观影投影设备,尤其是微型投影等领域,具有广阔的应用前景。With its excellent optical performance and compact design, it is suitable for various home viewing projection devices, especially in the field of micro-projection, etc., and has broad application prospects.

[0109] In some examples of this application, the central thickness T' of the triplet lens satisfies 8.5% ≤ T' / TTL ≤ 10%; where TTL is the overall optical length of the projection lens module.

[0110] In the examples provided herein, a thickness design is proposed for the triplet lens in the projection lens module, whereby the central thickness T' of the triplet lens and the total optical length TTL of the projection lens module should satisfy a ratio of 8.5% ≤ T' / TTL ≤ 10%. This design plays a key role in optimizing the optical performance of the projection lens module, ensuring structural compactness, and enhancing chromatic aberration correction capabilities.

[0111] As a key component in the projection lens module, the triplet's thickness (center thickness T') directly impacts the module's chromatic aberration correction capabilities. By adjusting the T' / TTL ratio, the triplet ensures that it provides adequate chromatic aberration correction without introducing other unnecessary optical aberrations. This ratio range (8.5% to 10%) is derived from a comprehensive evaluation of multiple optical performance indicators, aiming to achieve an optimal balance between chromatic aberration correction and other optical performance characteristics.

[0112] With the continuous development of projection technology, the demand for miniaturization and lightweighting of the entire projection lens module is increasing. By setting a reasonable T' / TTL ratio range, it is possible to achieve a compact design of the projection lens module while ensuring optical performance. This helps reduce the overall size and weight of the projection lens module, improving its portability and applicability.

[0113] The triplet lens is composed of multiple lens elements with different refractive indices, and its center thickness significantly affects the effectiveness of chromatic aberration correction. While a thicker triplet lens provides stronger chromatic aberration correction, it may increase the volume and weight of the entire projection lens module. A thinner triplet lens may not be able to meet the required chromatic aberration correction requirements. By setting the ratio range between 8.5% and 10%, we can ensure effective chromatic aberration correction while avoiding excessive increases in the volume of the projection lens module.

[0114] By precisely controlling the ratio of the center thickness T' of the triplet lens to its TTL, the chromatic aberration correction effect can be further optimized, improving the imaging quality of the projection lens module. This is of great significance for users who pursue high-quality projection effects.

[0115] In addition to improving chromatic aberration correction, controlling the center thickness T' of the triplet lens can also positively impact other optical properties of the projection lens module, such as spherical aberration and coma. By optimizing the T' / TTL ratio, the overall imaging quality of the projection lens module can be further improved, meeting user demands for high-definition, high-contrast projection effects.

[0116] While ensuring optical performance, a compact design of the projection lens module can be achieved by setting a reasonable T' / TTL ratio range. This helps reduce the overall volume and weight of the projection lens module, improving its portability and applicability.

[0117] In some examples of this application, see Figure 3 The triplet lens is composed of a seventh lens 7, an eighth lens 8 and a ninth lens 9 glued together in sequence, wherein: the seventh lens 7 and the ninth lens 9 both have positive focal power; the eighth lens 8 has negative focal power; and the refractive index of any one of the seventh lens 7 and the ninth lens 9 is lower than the refractive index of the eighth lens 8.

[0118] See also Figure 3 The triplet is located in the second lens group of the projection lens, adjacent to the aperture 11. This arrangement helps optimize the light propagation path and aberration correction. The triplet is composed of the seventh lens 7, the eighth lens 8, and the ninth lens 9, which are cemented together in sequence to form a compact optical unit.

[0119] The seventh lens 7 and the ninth lens 9 are both designed with positive optical power, and they converge light along the optical path. By properly designing the curvature and center thickness of these two lenses, they effectively converge light, providing the foundation for a clear projected image.

[0120] The eighth lens element 8, unlike the seventh and ninth lenses 7 and 9, has a negative optical power, which means it diverges light. The combination of a negative and positive optical power lens allows for precise control of light, correcting various aberrations such as spherical aberration and astigmatism.

[0121] It's particularly noteworthy that the refractive index of either the seventh lens element 7 or the ninth lens element 9 is lower than that of the eighth lens element 8. Materials with different refractive indices have different abilities to refract light. By selecting materials with lower refractive indices for the positive-power lenses (the seventh and ninth lenses 9) and materials with higher refractive indices for the negative-power lens (the eighth lens 8), more precise control of light can be achieved. Specifically, this design with different refractive indices facilitates:

[0122] (1) Correction of astigmatism and field curvature: By rationally combining lenses with different refractive indices, the propagation direction of light can be adjusted, thereby effectively correcting aberrations such as astigmatism and field curvature, and improving the clarity and flatness of the image.

[0123] (2) Controlling chromatic aberration: Chromatic aberration is one of the key issues to be considered in the design of projection lens modules. By selecting appropriate material combinations, the offset of light rays with different wavelengths at the focal point can be reduced, that is, chromatic aberration is controlled, thereby further improving the color reproduction and clarity of the projection image.

[0124] In summary, the design of the triplet lens in this example of the present application achieves fine control of light rays and effective correction of aberrations by precisely controlling the optical power and refractive index differences of the lenses. This design not only optimizes the imaging quality of the projection lens module, but also improves the overall performance and reliability of the projection lens module. In addition, this design helps to achieve the compactness and miniaturization of the lens, making it more suitable for application scenarios with limited space, such as micro-projection devices, etc.

[0125] In some examples of the present application, the refractive indices of the seventh lens 7 and the ninth lens 9 are N1 and N2 respectively, the refractive index of the eighth lens 8 is N3, and the triplet lens satisfies: 1.2 < N3 / (N1 + N2) < 1.3.

[0126] In the example of the present application, see Figure 3 , the triplet lens is composed of the seventh lens 7, the eighth lens 8 and the ninth lens 9 glued together in sequence. Among them, both the seventh lens 7 and the ninth lens 9 are positive-power lenses, and their refractive indices are defined as N1 and N2 respectively; while the eighth lens 8 is a negative-power lens, and its refractive index is defined as N3.

[0127] In this example of the present application, it is proposed that the triplet lens needs to satisfy a specific refractive index ratio condition, that is, 1.2 < N3 / (N1 + N2) < 1.3. This design condition plays an important role in improving the optical performance of the entire projection lens module. [[ID=_{15}]]

[0128] As positive-power lenses, the seventh lens 7 and the ninth lens 9 have relatively low refractive indices (N1 and N2). In optical design, positive-power lenses are mainly used to converge light rays, and the lower refractive indices help to reduce the deflection angle of light rays in the lenses, thereby reducing aberrations such as spherical aberration and astigmatism to a certain extent.

[0129] As a negative-power lens, the eighth lens 8 has a relatively high refractive index N3. Negative-power lenses are used to diverge light rays, and the higher refractive index enhances its diverging ability. By combining a negative lens with a high refractive index (N3) with positive lenses with low refractive indices (N_{1} and N2), more fine control of light rays can be achieved, thereby more effectively correcting aberrations such as astigmatism and field curvature.

[0130] The refractive index difference is not only a key factor for aberration correction but also an important means for controlling chromatic aberration. Chromatic aberration is one of the key issues to be considered in the design of a projection lens module. It causes the light rays of different wavelengths to shift at the focal point, affecting the imaging clarity. In this application, by controlling the refractive index ratio between the eighth lens 8 (a high-refractive-index negative lens) and the seventh lens 7 and the ninth lens 9 (low-refractive-index positive lenses) (i.e., 1.2 < N3 / (N1 + N2) < 1.3), the shift of light rays of different wavelengths at the focal point can be more effectively reduced, thereby controlling chromatic aberration and improving the imaging clarity and color reproducibility.

[0131] In summary, the triplet lens design in the example of this application realizes more precise control of light rays and effective correction of aberrations by controlling the refractive indices and refractive index ratios of the three lenses. This design not only significantly improves the optical performance of the projection lens module but also enhances the color reproducibility and clarity of the projection image. In addition, this design helps to achieve the compactification and miniaturization of the projection lens module, meeting the requirements of modern projection devices for light weight and portability.

[0132] In one example, both the seventh lens 7 and the ninth lens 9 are positive lenses, and the refractive index ranges of these two positive lenses are 1.49 to 1.56; the eighth lens 8 is a negative lens, and the refractive index range of this negative lens is 1.87 to 1.92.

[0133] Among them, both the seventh lens 7 and the ninth lens 9 have positive optical powers, and their refractive indices are set at 1.49 to 1.56. This refractive index range corresponds to some low-refractive-index optical materials, which have good transmittance and low dispersion characteristics.

[0134] Among them, the eighth lens 8 has a negative optical power, and its refractive index is set at 1.87 to 1.92. This refractive index range corresponds to some high-refractive-index optical materials, which can achieve a thinner lens thickness under the same optical power and also helps to correct chromatic aberration.

[0135] The combination of a high-refractive-index negative optical power lens and a low-refractive-index positive optical power lens can perform fine adjustment of the refraction path for light rays of different wavelengths, thereby reducing color distortion and improving the color reproducibility and clarity of the image.

[0136] The high-refractive-index negative optical power lens can achieve a thinner thickness while maintaining the same optical power, which helps to reduce the volume and weight of the entire projection lens module and achieve a more compact design.

[0137] In addition, materials with different refractive indices have different thermal expansion coefficients and mechanical properties. By properly matching these materials, the present application can reduce optical performance changes caused by temperature changes or mechanical stress, and enhance the stability of the entire projection lens module.

[0138] In some examples of the present application, the triplet lens satisfies 5<(T5+T6) / T7<6, where: T5 is the center thickness of the seventh lens 7, T6 is the center thickness of the eighth lens 8, and T7 is the center thickness of the ninth lens 9.

[0139] In the example provided in this application, a thickness ratio design is proposed for one of the key components of the projection lens module—the triplet lens (composed of the seventh lens 7, the eighth lens 8, and the ninth lens 9 cemented in sequence)—that satisfies the condition 5 < (T5 + T6) / T7 < 6. Here, T5 represents the center thickness of the seventh lens 7, T6 represents the center thickness of the eighth lens 8, and T7 represents the center thickness of the ninth lens 9. This thickness ratio design plays an important role in optimizing the optical performance of the triplet lens, ensuring structural compactness, and improving overall imaging quality.

[0140] As an important component of the projection head module, one of the main functions of the triplet lens is to correct chromatic aberration. Chromatic aberration is a problem that needs to be overcome in lens design. It will cause light of different wavelengths to shift in focus, thereby affecting the clarity of the image. By controlling the center thickness ratio of the positive and negative lenses (the seventh lens 7 and the ninth lens 9 are positive, and the eighth lens 8 is negative) (i.e. 5<(T5+T6) / T7<6), the chromatic aberration correction capability of the triplet lens can be further optimized. This optimization helps to reduce the offset of light of different wavelengths in focus, thereby significantly improving the color reproduction and contrast of the projection lens module.

[0141] In addition to chromatic aberration correction, the triplet lens also provides a certain degree of control over other aberrations, such as spherical aberration and coma, which can also affect image quality, resulting in blurred or distorted images.

[0142] By adjusting the center thickness ratio of the positive and negative lenses in the triplet, the correction effect of these aberrations can be further optimized. This optimization helps to improve image clarity and resolution, making the projected image more detailed and realistic.

[0143] Furthermore, while ensuring optical performance, a compact projection lens module design can be achieved by setting a reasonable lens center thickness ratio range (i.e., 5 < (T5 + T6) / T7 < 6). This compact design not only helps reduce the size and weight of the device, but also lowers production costs.

[0144] The triplet lens thickness ratio design in this example achieves effective correction of chromatic aberration and aberration by precisely controlling the center thickness ratio of the positive and negative lenses, while ensuring the compactness and lightweight nature of the projection lens module. This design not only significantly improves the optical performance of the projection lens module but also supports its application in various projection devices.

[0145] In some examples of this application, see Figure 3 The doublet lens is composed of a fifth lens 5 and a sixth lens 6 glued together, wherein: the optical focal lengths of the fifth lens 5 and the sixth lens 6 are opposite, one of the fifth lens 5 and the sixth lens 6 has positive optical power, and the other has negative optical power, and the refractive index of the lens with positive optical power is higher than the refractive index of the lens with negative optical power.

[0146] In the examples provided herein, the doublet lens in the projection lens module serves as another important optical element, and its design significantly impacts the optical performance of the entire projection lens module. The doublet lens is composed of a fifth lens 5 and a sixth lens 6 bonded together. Its unique design feature is that the fifth and sixth lenses 5 and 6 have opposite focal powers—one with positive power and the other with negative power. This design combination plays a crucial role in the projection lens module, facilitating precise control of light and effective correction of aberrations.

[0147] The fifth lens 5 and the sixth lens 6 have opposite focal powers: one converges light (positive power) and the other diverges light (negative power). This design balances the convergence and divergence of light, thereby minimizing aberrations such as spherical aberration and astigmatism.

[0148] Based on the opposite optical powers, this example further specifies that the refractive index of the positive power lens (fifth lens 5) is N5, and the refractive index of the negative power lens (sixth lens 6) is N6, satisfying the condition N5>N6. This refractive index difference is designed based on the characteristics of optical materials and the principle of aberration correction. Materials with higher refractive indices have stronger light converging or diverging capabilities. Therefore, by selecting a material combination with appropriate refractive indices, the optical performance of the doublet can be further optimized.

[0149] The opposing focal powers of the doublet lens allow light to converge and then diverge, or diverge and then converge, as it passes through the lens. This process helps balance aberrations in light propagation. Furthermore, by controlling the difference in refractive index between the two lenses, light control can be further refined, achieving even higher-precision aberration correction.

[0150] The design of the doublet lens effectively improves the optical performance of the entire projection lens module. It can reduce aberrations, improve imaging clarity, enhance key indicators such as color rendition and contrast. This is particularly important for projection devices as they need to present high-quality, high-definition images to meet users' viewing needs.

[0151] The design of the doublet lens also helps to achieve the compactification and miniaturization of the lens. By gluing two lenses together, the overall volume of the projection lens module can be reduced, thus meeting the requirements of modern projection devices for lightweight and portability.

[0152] In the example provided in this application, the design of the doublet lens realizes the fine control of light rays and the effective correction of aberrations by controlling the difference in the optical power and refractive index of the two lenses. This design not only significantly improves the optical performance of the projection lens module but also provides support for the compactification and miniaturization of the projection lens module.

[0153] In some examples of this application, the fifth lens 5 has a positive optical power and a refractive index of N5, and the sixth lens 6 has a negative optical power and a refractive index of N6, and the following is satisfied between N5 and N6: 1.03 < N5 / N6 < 1.1.

[0154] As a key element in the projection lens module, one of the design purposes of the doublet lens is to correct the aberrations in the projection lens film module. By setting the refractive index ratio of 1.03 < N5 / N6 < 1.1, the refractive indices of the positive lens and the negative lens are precisely controlled. This appropriate refractive index ratio can effectively enhance the correction ability of the doublet lens for aberrations (such as spherical aberration, astigmatism, etc.). A higher refractive index ratio means that the converging effect of the positive lens on light rays is relatively strong, while the diverging effect of the negative lens is relatively weak. This design combination helps to balance the aberrations in light propagation, thereby improving the imaging quality.

[0155] In addition to enhancing the aberration correction ability, this refractive index ratio design also helps to optimize the overall optical performance of the doublet lens. By precisely controlling the refractive index ratio of the lens, the propagation path and convergence point position of light rays can be better controlled, thereby reducing key optical indicators such as spot size, improving resolution and contrast. This is particularly important for projection devices as they need to present high-quality, high-definition images to meet users' viewing needs.

[0156] In one example, the fifth lens 5 is a positive lens, and the refractive index N5 of the positive lens ranges from 1.88 to 1.95; the sixth lens 6 is a negative lens, and the refractive index N6 of the negative lens ranges from 1.75 to 1.82.

[0157] In the above example, the fifth lens 5 is a positive lens and is the converging element in the doublet lens. Its refractive index N5 is in a relatively high range. The positive lens with a high refractive index can converge light more effectively, thereby improving the imaging ability of the projection lens module. The sixth lens 6 is a negative lens. In contrast, the refractive index N6 of this negative lens is slightly lower. The main function of the negative lens is to diverge light and cooperate with the positive lens to jointly achieve the regulation of light.

[0158] According to the example provided by the present application, by controlling the refractive index ratio of the positive lens and the negative lens, the doublet lens can better correct aberration. The converging effect of the positive lens and the diverging effect of the negative lens cancel each other out, and an appropriate refractive index ratio ensures that this cancellation effect is more precise and effective, thereby reducing the deflection error of light during propagation and improving the imaging quality.

[0159] The refractive index difference is also a means of controlling chromatic aberration. By setting an appropriate refractive index ratio, the doublet lens can reduce the shift of light with different wavelengths at the focus, that is, chromatic aberration, to a certain extent. This is crucial for improving the color reproduction and clarity of the image.

[0160] Combining the advantages of the above aberration correction and chromatic aberration control, the doublet lens design in this example of the present application significantly improves the imaging quality of the projection lens module, which includes aspects such as improving the resolution, contrast, and color saturation of the image, bringing a better visual experience to users.

[0161] In some examples of the present application, the first lens group satisfies: 0.95 < T3 / (T1 + T2) < 1.3, where: T1 is the central thickness of the first lens 1, T2 is the central thickness of the second lens 2, and T3 is the central thickness of the third lens 3.

[0162] In the example provided by the present application, a specific design of the lens central thickness ratio is proposed for the first lens group (composed of three negative lenses, namely the first lens 1, the second lens 2, and the third lens 3) in the projection lens module. Specifically, a specific proportional relationship needs to be satisfied among the central thickness T1 of the first lens 1, the central thickness T2 of the second lens 2, and the central thickness T3 of the third lens 3, that is, 0.95 < T3 / (T1 + T2) < 1.3. This design plays a key role in optimizing the optical performance, structural compactness, and environmental adaptability of the projection lens module.

[0163] The center thickness of a lens is a key factor influencing its imaging performance. In this application, by controlling the center thickness ratio of the three negative lenses in the first lens group, their convergence and divergence of light can be effectively optimized, thereby more effectively correcting aberrations. An appropriate thickness ratio helps balance the degree of light deflection by each lens, reducing deflection errors during light propagation, thereby improving imaging quality.

[0164] While ensuring image quality, controlling the center-to-center thickness ratio of the lens can also achieve a compact design of the projection lens module. A smaller lens thickness helps reduce the size and weight of the projection lens module, making it more suitable for space-constrained applications such as micro-projection equipment.

[0165] A reasonable lens center-to-center thickness ratio also helps ensure the stability of the projection lens module in various environments. Under conditions such as temperature fluctuations or mechanical vibration, a proper lens center-to-center thickness ratio can minimize variations in image quality caused by lens deformation, thereby improving the reliability and durability of the projection lens module. This is particularly important for projection equipment that must operate in a variety of environments.

[0166] In summary, the center thickness ratio design of the first lens group proposed in this example of the present application significantly optimizes the optical performance, structural compactness and environmental adaptability of the projection lens module by precisely controlling the center thickness ratio of the three negative lenses.

[0167] In some examples of the present application, the center thickness T1 of the first lens 1 satisfies 3.3%≤T1 / TTL≤3.7%; the center thickness T2 of the second lens 2 satisfies 1.5%≤T2 / TTL≤1.8%; wherein TTL is the total optical length of the projection lens module.

[0168] In some examples of this application, specific constraints on the ratio between the center thickness of the lens and the total optical length (TTL) of the projection lens module are proposed for the first lens group in the projection lens module (mainly composed of negative lenses such as the first lens 1 and the second lens 2). Specifically, the center thickness T1 of the first lens 1 must satisfy 3.3% ≤ T1 / TTL ≤ 3.7%, while the center thickness T2 of the second lens 2 must satisfy 1.5% ≤ T2 / TTL ≤ 1.8%. This design constraint plays an important role in optimizing the optical performance of the entire projection lens module, ensuring structural compactness, and improving manufacturing feasibility.

[0169] As one of the components of the projection lens module, the central thickness T1 of the first lens 1 and its ratio to TTL directly affect the imaging quality of the projection lens. By setting the ratio range of 3.3% ≤ T1 / TTL ≤ 3.7%, it can be ensured that the first lens has sufficient thickness to provide good imaging performance and aberration correction ability, while avoiding the increase in volume and weight caused by an overly thick lens. The selection of this ratio range is based on a comprehensive consideration of the lens imaging performance, aberration correction, and the compactness of the lens structure.

[0170] The thickness ratio design of the second lens 2, that is, 1.5% ≤ T2 / TTL ≤ 1.8%, is equally important. It helps to balance the imaging performance of the entire projection lens module, ensure the effective cooperation between lenses, and jointly achieve fine control of light and effective correction of aberrations.

[0171] On the premise of ensuring imaging quality, by controlling the ratio of the central thickness of the lens to TTL, a compact design of the projection lens module can be achieved. A smaller lens thickness ratio helps to reduce the overall volume and weight of the projection lens module, making it more suitable for application scenarios with limited space.

[0172] In addition, a reasonable lens thickness ratio design also helps to improve the manufacturing feasibility of the projection lens module. Thinner lenses may face higher difficulties and costs during the processing, while overly thick lenses may increase material consumption and processing time. By setting an appropriate ratio range of the lens thickness to TTL, the manufacturing difficulty and cost can be reduced while ensuring imaging quality and structural compactness, improving the production efficiency and economic benefits of the product.

[0173] In some examples of this application, the sagittal height of the surface of the second lens 2 on the side away from the aperture 11 at the maximum aperture is S1, and the sagittal height of the surface on the side close to the aperture 11 at the maximum aperture is S2, and it satisfies: 3.5 < S2 / S1 < 4.�.

[0174] In the examples provided in this application, for the second lens 2 in the projection lens module, a specific sagittal height ratio design constraint is proposed. Specifically, the sagittal height of the surface of the second lens 2 on the side away from the aperture 11 at the maximum aperture is defined as S1, and the sagittal height of the surface on the side close to the aperture 11 at the maximum aperture is defined as S2, and S1 and S2 need to satisfy the condition: 3.5 < S2 / S1 < 4.5. This design constraint plays a key role in improving the optical performance of the projection lens module, optimizing the light propagation path, and enhancing the aberration correction ability.

[0175] The sagittal height is an important parameter describing the surface shape of the lens, which directly affects the propagation path of light. By controlling the ratio of the sagittal heights of the two surfaces of the second lens 2 (S2 / S1), the deflection angle and path of light passing through the second lens 2 can be optimized, thereby reducing the loss and distortion of light during propagation.

[0176] A reasonable setting of the sagittal height ratio helps to enhance the aberration correction ability of the second lens 2. Aberration is one of the main factors affecting the imaging quality of the projection lens module, including spherical aberration, coma, astigmatism, etc. By adjusting the sagittal height ratio of the second lens 2, these aberrations can be effectively corrected, thereby improving the clarity and resolution of the image.

[0177] Especially for primary aberrations such as spherical aberration and coma, the control of the sagittal height ratio is particularly important. These aberrations are often caused by inconsistent deflection angles or asymmetric light paths when light passes through the lens. By setting the ratio range of S2 / S1, the light can maintain a more consistent deflection angle and a more symmetric path when passing through the second lens 2, thereby reducing the influence of these aberrations.

[0178] In summary, by controlling the sagittal height ratio (S2 / S1) of the second lens 2, the light propagation path can be optimized and the aberration correction ability can be enhanced, thereby improving the optical performance of the entire projection lens module. This design constraint not only improves the imaging quality but also provides support for high-quality imaging of projection devices in various application scenarios.

[0179] The design of the sagittal height ratio of the second lens proposed in this example of the application significantly optimizes the optical performance of the projection lens module by precisely controlling the ratio of the sagittal heights of the two surfaces (S2 / S1). This design not only optimizes the light propagation path, reduces light loss and distortion, but also enhances the lens's aberration correction ability and improves the clarity and resolution of the image.

[0180] In some examples of this application, refer to Figure 4 , on the side of the second lens 2 away from the diaphragm 11, the angle between the tangent line at the maximum aperture of the surface and the optical axis is A1, and on the side of the second lens 2 close to the diaphragm 11, the angle between the tangent line at the maximum aperture of the surface and the optical axis is A2, and it satisfies: 40° < A1 - A2 < 50°, and 1.8 < A1 / A2 < 2.3.

[0181] In the examples provided in this application, a refined optical design was carried out for the second lens 2 in the projection lens module. In particular, the angles between the tangents of the surfaces on the side away from the aperture 11 and the side close to the aperture 11 of the second lens 2 at the maximum aperture with respect to the optical axis (denoted as A1 and A2 respectively) were controlled. Specifically, it is required that 40° < A1 - A2 < 50° and 1.8 < A1 / A2 < 2.3. This design plays a key role in optimizing the light deflection angle, reducing distortion, and improving the overall optical performance of the projection lens module.

[0182] By controlling the magnitudes of A1 and A2 and their relationship, the deflection angle of light when passing through the second lens 2 can be optimized. An appropriate angle difference (40° < A1 - A2 < 50°) ensures that the deflection of light in the second lens 2 is neither too drastic nor too gentle, thus contributing to correcting the aberration introduced by other lenses and improving the imaging quality.

[0183] Meanwhile, the setting of the angle ratio (1.8 < A1 / A2 < 2.3) further refines the control of the light deflection angle, enabling the light to be more evenly distributed inside the projection lens module and reducing the loss and distortion during the light deflection process.

[0184] Distortion is an important aberration index in the projection lens module, directly affecting the fidelity of the projection image and the user's visual experience. In this application, by controlling the relationship between the tangents of the second lens 2 at the maximum aperture and the optical axis, the distortion of the entire projection lens module is significantly reduced.

[0185] Even at a large field angle of 55° - 59°, the projection lens module of this application can still control the distortion at a low level (such as within 1.5%), which is about 30% lower than that of similar products. This achievement benefits from the refined design of the angle between the tangent of the second lens 2 and the optical axis, effectively optimizing the light propagation path and deflection angle.

[0186] Through the above design, the projection lens module of this application has achieved a significant improvement in optical performance. The improvement in imaging quality makes the projection image clearer, more realistic, and with higher color reproducibility, thus enhancing the user's visual experience. At the same time, the low distortion level also ensures the shape fidelity of the projection image, avoiding shape distortion problems caused by distortion and further enhancing the user's visual experience.

[0187] In summary, in this example of the present application, by precisely controlling the magnitudes of A1 and A2 and their relationship for the angle between the tangent of the second lens 2 and the optical axis, the light deflection angle is significantly optimized, the distortion is reduced, and the overall optical performance of the projection lens module is improved. While ensuring the imaging quality, this design also enhances the user's visual experience, providing strong support for the technological progress and application expansion in the field of projection lenses. In addition, in combination with other optical designs of the projection lens module (such as the "negative-negative-negative-positive-double cemented (positive)" structure of the first lens group and the "triple cemented (negative)-positive" structure of the second lens group), the projection lens module of the present application achieves a reasonable optical power distribution and excellent imaging quality, demonstrating its outstanding technical advantages and application prospects.

[0188] In some examples of the present application, referring to Figure 5 , the angle between the tangent of the surface of the third lens 3 on the side away from the aperture stop 11 at the maximum aperture and the optical axis is A3, and the angle between the tangent of the surface of the third lens 3 on the side close to the aperture stop 11 at the maximum aperture and the optical axis is A4, and it satisfies: 40° < A3 - A4 < 60°, and 1.6 < A3 / A4 < 2.1.

[0189] In the examples provided by the present application, specific angle constraint conditions are proposed for the third lens 3 in the projection lens module, and these conditions are closely related to the angles between the tangents of the two surfaces of the third lens 3 at the maximum aperture and the optical axis. Specifically, referring to Figure 5 , the angle between the tangent of the surface of the third lens 3 on the side away from the aperture stop 11 at the maximum aperture and the optical axis is denoted as A3, and the angle between the tangent of the surface of the third lens 3 on the side close to the aperture stop 11 at the maximum aperture and the optical axis is denoted as A4. These two angles need to satisfy the following constraint conditions: 40° < A3 - A4 < 60°, and 1.6 < A3 / A4 < 2.1. This design plays an important role in optimizing the optical performance of the projection lens module.

[0190] The control of the angle difference A3 - A4 (40° < A3 - A4 < 60°) is important for optimizing the deflection degree and direction of the light passing through the third lens 3. An appropriate angle difference helps to balance the converging and diverging effects of the light in the lens, thereby effectively reducing aberration and improving the imaging quality. This design is based on an in-depth understanding of the light propagation characteristics and the aberration generation mechanism, ensuring that the light can maintain good parallelism and directionality after passing through the third lens 3.

[0191] At the same time, the constraint of the angle ratio A3 / A4 (1.6 < A3 / A4 < 2.1) further refines the control of the shape of the third lens 3 and the optical path design. A reasonable angle ratio helps to ensure the rationality of the lens shape and the stability of the optical path design, reducing imaging quality problems caused by changes in the lens shape or optical path offset.

[0192] By controlling the angular difference and angular ratio between the two surfaces of the third lens 3, the design in this example achieves fine control of light and effective correction of aberrations. This not only reduces light loss and deflection errors during propagation, but also improves light utilization and image quality.

[0193] Specifically, this design significantly enhances the projection lens module's contrast, color reproduction, and detail. Image clarity and resolution are significantly improved, resulting in clearer, more detailed projections and more realistic, richer colors.

[0194] In addition to optimizing light deflection and aberration correction, the angle design in this example of the present application also takes into account the reliability and stability of the lens design. By setting a reasonable angle ratio A3 / A4, the rationality of the shape of the third lens 3 and the stability of the optical path design are ensured. This helps to reduce the impact of external factors (such as temperature changes, mechanical vibrations, etc.) on the lens shape and optical path, and improve the reliability and durability of the projection lens.

[0195] In summary, the design of the angle between the tangent line and the optical axis of the third lens 3 in this example of the present application significantly optimizes light deflection, aberration correction, and image quality by precisely controlling the angle difference and angle ratio. This design not only ensures high optical performance of the projection lens module, but also enhances the reliability and stability of the projection lens module design.

[0196] In some examples of this application, see Figure 3 The projection lens module further includes a prism 12, a glass plate 14 and a display unit 13 which are arranged in sequence along the side of the tenth lens 10 away from the aperture 11.

[0197] In the example provided in this application, the projection lens module includes not only two lens groups and an aperture 11, but also a prism 12. Specifically, the prism 12 is located on the side of the tenth lens 10 away from the aperture 11. This is to achieve light deflection or reflection to adapt to specific projection requirements or optical path layouts. In addition, the provision of the prism 12 can increase the functionality of the projection lens, such as changing the direction of the light path, achieving projection at a specific angle, etc. At the same time, it is necessary to ensure the optical matching between the prism 12 and the lens group to avoid additional aberrations or light loss.

[0198] In the specific implementation of the prism 12, a total internal reflection prism (TIR prism) design can be selected. The TIR prism, with its efficient light reflection characteristics, can minimize light loss and ensure the brightness and color saturation of the projected image.

[0199] The addition of the glass plate 14 also provides an additional optical surface for the projection lens module, potentially used to adjust the phase and polarization of light or serve as a protective window, further enhancing the stability and durability of the entire projection lens module. The display unit 13, serving as the source of projection content, works closely with the prism 12, the glass plate 14, the two lens assemblies, and the aperture 11 to produce a high-quality, high-definition projection image.

[0200] Specifically, the display unit 13, as a component of the projection lens module, is responsible for generating and providing light for projection imaging to the projection lens. The display unit 13 is, for example, a high-resolution display device such as LCD, DLP or LCOS, capable of generating high-quality image signals.

[0201] In some examples of this application, see Figure 3 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 satisfies: 1.5<TTL / D1<1.9.

[0202] In the examples provided in this application, the ratio between the total optical length (TTL) of the projection lens module and the maximum aperture (D1) of the lens was designed to ensure that this ratio falls within the range of 1.5 < TTL / D1 < 1.9. This design parameter is directly related to several key aspects of the projection lens module, including compactness, image quality, and manufacturing cost.

[0203] TTL, the total optical length of a projection lens module, is an important metric for measuring lens size and compactness. By limiting the ratio of TTL to D1 to between 1.5 and 1.9, the design of this application ensures sufficient light transmission (determined by D1) while also ensuring the compactness of the projection lens module. This balanced design enables the projection lens to be miniaturized and lightweight while maintaining high-quality imaging, meeting the portability and space utilization requirements of modern projectors.

[0204] As the maximum aperture of the lens, D1 not only affects the light transmission capacity of the lens, but also directly relates to the rationality of the optical path design. By setting a reasonable TTL / D1 ratio range, this design helps to optimize the optical path layout, reduce the loss and distortion of light during propagation, and thus improve the imaging quality. In this application, see Figure 3 , the lens with the largest aperture is the first lens 1.

[0205] While ensuring image quality and compactness, controlling the TTL / D1 ratio also helps reduce the manufacturing cost of projection lenses. A shorter TTL means less material and a simpler manufacturing process, thus reducing production costs. This is of great significance for improving the market competitiveness of products.

[0206] In some examples of this application, see Figure 3 , the effective focal lengths of the lenses in the projection lens are:

[0207] The effective focal length of the first lens 1 is F1, -32mm≤F1≤-24mm;

[0208] The effective focal length of the second lens 2 is F2, -19mm≤F2≤-14mm;

[0209] The effective focal length of the third lens 3 is F3, -19mm≤F3≤-14mm;

[0210] The effective focal length of the fourth lens 4 is F4, 25mm≤F4≤36mm;

[0211] The effective focal length of the doublet lens is F', 17mm≤F'≤25mm;

[0212] The effective focal length of the triplet lens is F", -80mm≤F"≤-55mm;

[0213] The effective focal length of the tenth lens 10 is F10, 9mm≤F10≤14mm.

[0214] In the example provided in this application, the effective focal length range of the first lens (F1) is: -32mm≤F1≤-24mm. As the front-end lens of the projection lens module, the first lens 1 is responsible for collecting and correcting light. Its larger negative focal length design helps to expand the field of view of the projection lens, allowing the projection lens module to capture a wider range of scenes. At the same time, this design also helps to reduce the aberration of light when entering the projection lens module, providing a basis for subsequent lens correction work.

[0215] The effective focal length range of the second lens (F2) and the third lens (F3) is: -19mm≤F2, F3≤-14mm. The focal length range of the second lens 2 and the third lens 3 is similar, and they jointly play the role of further correcting aberrations. The appropriate negative focal length design not only helps to reduce the overall length of the projection lens and achieve a compact design, but also effectively corrects the aberrations generated by light during propagation and improves imaging quality. The close cooperation of these two lenses ensures that light can maintain good parallelism and directionality when passing through them.

[0216] The effective focal length range of the fourth lens (F4) is 25mm ≤ F4 ≤ 36mm. As a positive lens in the projection lens module, the fourth lens 4 primarily deflects light, allowing it to smoothly pass through the subsequent lens groups and converge onto the imaging surface. Its larger positive focal length contributes to clear imaging, improving image contrast and detail. Furthermore, the addition of a positive lens also helps balance the optical power distribution within the lens module, improving the imaging performance of the entire system.

[0217] The effective focal length range of the doublet lens (F') is 17mm ≤ F' ≤ 25mm. Composed of two lenses with different refractive indices bonded together, the doublet lens offers excellent chromatic aberration correction. This focal length range helps further optimize the imaging quality of the projection lens module, reducing image blur and color distortion caused by chromatic aberration. The doublet lens design enables the lens to maintain excellent imaging performance over a wider wavelength range.

[0218] The effective focal length range of the triplet lens (F") is -80mm ≤ F" ≤ -55mm. Made up of three lenses with different refractive indices bonded together, the triplet lens offers enhanced aberration correction capabilities. Its larger negative focal length helps expand the projection range of the projection lens module, enabling short-throw projection. The triplet's structure also enables more effective correction of higher-order aberrations (such as spherical aberration and coma), improving imaging quality.

[0219] The effective focal length range of the tenth lens (F10) is 9mm ≤ F10 ≤ 14mm. As the final lens in the projection lens module, the positive focal length design of the tenth lens 10 contributes to high-quality imaging. It not only further corrects aberrations and distortions caused by light propagation, but also ensures that light is accurately focused on the imaging surface, forming a clear and detailed image.

[0220] By precisely defining the effective focal length range of each lens in the projection lens module, this application achieves precise control and focusing of light. The combination of lenses with different focal lengths not only optimizes the optical path design and improves image quality, but also achieves a compact and miniaturized lens design.

[0221] In some examples of the present application, the second lens 2 to the ninth lens 9 are glass spherical lenses.

[0222] In the examples provided herein, the selection of second lens 2 through ninth lens 9 as glass spherical lenses is primarily based on a combination of optical performance and manufacturing cost considerations. Specifically, glass spherical lenses can meet the high imaging quality requirements of projection lenses while also being relatively inexpensive to manufacture, thereby reducing overall lens production costs.

[0223] Glass spherical mirrors have excellent optical properties, reducing light scattering and absorption, and improving image clarity and contrast. Glass spherical mirrors are relatively inexpensive to manufacture, and choosing them as the material for lens elements 2 through 9 helps reduce the production cost of projection lenses.

[0224] Furthermore, glass materials offer high thermal and chemical stability, maintaining stable optical performance under varying environmental conditions. This helps enhance the stability of the entire projection system, improving product reliability and service life. Spherical mirrors are also relatively simple in design and can be easily combined with other optical components.

[0225] In some examples of the present application, the focal length of the projection lens module is 2.83 mm, the projection ratio TR is 0.5, the relative aperture is 1 / 1.699, the offset is 140%, the pixel size is 5.4 μm, the field of view angle is 55° to 59°, the image plane size is 8.5 mm to 9.1 mm, and the operating band is 455 nm to 630 nm.

[0226] Focal length is one of the most fundamental parameters in lens design, determining the lens's ability to focus light. The projection lens module in this application has a focal length of 2.83mm, a short-throw design suitable for short-distance projection scenarios. This short-throw design enables the projector to project a larger image at a closer distance, saving space and improving ease of use.

[0227] Throw ratio refers to the ratio of projection distance to image width. The projection lens module in this application has a throw ratio of 0.5, meaning that at the same projection distance, the lens can project a wider image. This feature makes the lens particularly suitable for environments with limited space, such as home living rooms and small conference rooms.

[0228] The relative aperture reflects the light transmission capacity of the lens. The relative aperture of the projection lens module of the present application is 1 / 1.699, indicating that the projection lens module has a larger entrance pupil diameter, which can receive more light, thereby improving the brightness and contrast of the image.

[0229] Offset refers to the percentage of the vertical distance from the bottom edge of the projected image to the bottom of the projector divided by the distance from the projector lens to the projected image. The projection lens module in this application has an offset of 140%, which means the projected image can be positioned away from the projector body, reducing shadows caused by obstructions from the projector body and improving the viewing experience.

[0230] The projection lens module of this application is adapted to a pixel size of 5.4μm, which helps maintain image clarity and detail at high resolution. The projection lens module of this application has a field of view of 55° to 59°. The wider field of view allows the lens to capture a wider range of scenes, making it suitable for large-screen projection and wide-format display. The projection lens module of this application is adapted to an image plane size of 8.5mm to 9.1mm, which helps ensure that the image can be projected completely and clearly onto the screen.

[0231] The projection lens module of the present application has an operating band of 455nm to 630nm, covering most of the range of visible light and is suitable for color projection and high-definition video playback.

[0232] The projection lens module of this application achieves excellent optical performance, including short throw, large throw ratio, high brightness, and a wide field of view. These performance characteristics make the lens module particularly suitable for short-distance projection requirements in scenarios such as modern home theaters and small conference rooms. Furthermore, by optimizing the lens structure design and material selection, the projection lens module also achieves a compact and lightweight design, improving the product's portability and market competitiveness.

[0233] According to another embodiment of the present application, a projection device is provided, comprising a housing and the projection lens module as described above.

[0234] The specific implementation of the projection device of 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.

[0235] The projection lens module of the present application is described below through Examples 1 to 5.

[0236] Example 1

[0237] See also Figure 6 The projection lens module provided in Example 1 includes a projection lens, a glass plate 14, and a display unit 13 arranged in sequence along the same optical axis; wherein the display unit 13 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 13 into an image;

[0238] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0239] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a doublet lens, which are sequentially arranged along the optical axis. The doublet lens is composed of a fifth lens 5 and a sixth lens 6 glued together. The first lens 1 is a plastic aspherical lens with negative optical power, the second lens 2 has negative optical power, the third lens 3 has negative optical power, the fourth lens 4 has positive optical power, and the doublet lens has positive optical power.

[0240] The second lens group includes a triplet lens and a tenth lens 10 arranged in sequence along the optical axis. The triplet lens is composed of a seventh lens 7, an eighth lens 8, and a ninth lens 9 cemented together, and the triplet lens has negative optical power. The tenth lens 10 is a glass aspherical lens with positive optical power.

[0241] The second lens 2 to the ninth lens 9 are all glass spherical lenses;

[0242] The aperture 11 is located between the doublet lens and the triplet lens;

[0243] The projection lens further includes a prism 12 disposed between the tenth lens 10 and the glass plate 14 .

[0244] See Table 1, which shows Figure 6 Some optical parameters of the projection lens module are provided.

[0245] Table 1

[0246]

[0247]

[0248]

[0249] Figure 6 The aspheric parameters of the projection lens module shown are shown in Table 2.

[0250] Table 2

[0251]

[0252] Example 2

[0253] See also Figure 7 The projection lens module provided in Example 2 includes a projection lens, a glass plate 14, and a display unit 13 arranged in sequence along the same optical axis; wherein the display unit 13 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 13 into an image;

[0254] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0255] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a doublet lens, which are sequentially arranged along the optical axis. The doublet lens is composed of a fifth lens 5 and a sixth lens 6 glued together. The first lens 1 is a plastic aspherical lens with negative optical power, the second lens 2 has negative optical power, the third lens 3 has negative optical power, the fourth lens 4 has positive optical power, and the doublet lens has positive optical power.

[0256] The second lens group includes a triplet lens and a tenth lens 10 arranged in sequence along the optical axis. The triplet lens is composed of a seventh lens 7, an eighth lens 8, and a ninth lens 9 cemented together, and the triplet lens has negative optical power. The tenth lens 10 is a glass aspherical lens with positive optical power.

[0257] The second lens 2 to the ninth lens 9 are all glass spherical lenses;

[0258] The aperture 11 is located between the doublet lens and the triplet lens;

[0259] The projection lens further includes a prism 12 disposed between the tenth lens 10 and the glass plate 14 .

[0260] See also Figure 7 , Figure 7 Some optical parameters of the projection lens module are shown in Table 3 below.

[0261] Table 3

[0262]

[0263]

[0264] The aspheric parameters of the projection lens module provided in Example 2 are shown in Table 4.

[0265] Table 4

[0266]

[0267]

[0268] Example 3

[0269] See also Figure 8The projection lens module provided in Example 3 includes a projection lens, a glass plate 14, and a display unit 13 arranged in sequence along the same optical axis; wherein the display unit 13 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 13 into an image;

[0270] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0271] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a doublet lens, which are sequentially arranged along the optical axis. The doublet lens is composed of a fifth lens 5 and a sixth lens 6 glued together. The first lens 1 is a plastic aspherical lens with negative optical power, the second lens 2 has negative optical power, the third lens 3 has negative optical power, the fourth lens 4 has positive optical power, and the doublet lens has positive optical power.

[0272] The second lens group includes a triplet lens and a tenth lens 10 arranged in sequence along the optical axis. The triplet lens is composed of a seventh lens 7, an eighth lens 8, and a ninth lens 9 cemented together, and the triplet lens has negative optical power. The tenth lens 10 is a glass aspherical lens with positive optical power.

[0273] The second lens 2 to the ninth lens 9 are all glass spherical lenses;

[0274] The aperture 11 is located between the doublet lens and the triplet lens;

[0275] The projection lens further includes a prism 12 disposed between the tenth lens 10 and the glass plate 14 .

[0276] See also Figure 8 , Figure 8 Some optical parameters of the projection lens module are shown in Table 5 below.

[0277] Table 5

[0278]

[0279]

[0280]

[0281] The aspheric parameters of the projection lens module provided in Example 3 are shown in Table 6.

[0282] Table 6

[0283]

[0284] Example 4

[0285] See also Figure 9 The projection lens module provided in Example 4 includes a projection lens, a glass plate 14, and a display unit 13 arranged in sequence along the same optical axis; wherein the display unit 13 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 13 into an image;

[0286] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0287] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a doublet lens, which are sequentially arranged along the optical axis. The doublet lens is composed of a fifth lens 5 and a sixth lens 6 glued together. The first lens 1 is a plastic aspherical lens with negative optical power, the second lens 2 has negative optical power, the third lens 3 has negative optical power, the fourth lens 4 has positive optical power, and the doublet lens has positive optical power.

[0288] The second lens group includes a triplet lens and a tenth lens 10 arranged in sequence along the optical axis. The triplet lens is composed of a seventh lens 7, an eighth lens 8, and a ninth lens 9 cemented together, and the triplet lens has negative optical power. The tenth lens 10 is a glass aspherical lens with positive optical power.

[0289] The second lens 2 to the ninth lens 9 are all glass spherical lenses;

[0290] The aperture 11 is located between the doublet lens and the triplet lens;

[0291] The projection lens further includes a prism 12 disposed between the tenth lens 10 and the glass plate 14 .

[0292] See also Figure 9 , Figure 9 Some optical parameters of the projection lens module are shown in Table 7 below.

[0293] Table 7

[0294]

[0295]

[0296] The aspheric parameters of the projection lens module provided in Example 4 are shown in Table 8.

[0297] Table 8

[0298]

[0299] Example 5

[0300] See also Figure 10 The projection lens module provided in Example 5 includes a projection lens, a glass plate 14, and a display unit 13 arranged in sequence along the same optical axis; wherein the display unit 13 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 13 into an image;

[0301] The projection lens comprises a first lens group, a second lens group and an aperture 11 arranged along the same optical axis;

[0302] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a doublet lens, which are sequentially arranged along the optical axis. The doublet lens is composed of a fifth lens 5 and a sixth lens 6 glued together. The first lens 1 is a plastic aspherical lens with negative optical power, the second lens 2 has negative optical power, the third lens 3 has negative optical power, the fourth lens 4 has positive optical power, and the doublet lens has positive optical power.

[0303] The second lens group includes a triplet lens and a tenth lens 10 arranged in sequence along the optical axis. The triplet lens is composed of a seventh lens 7, an eighth lens 8, and a ninth lens 9 cemented together, and the triplet lens has negative optical power. The tenth lens 10 is a glass aspherical lens with positive optical power.

[0304] The second lens 2 to the ninth lens 9 are all glass spherical lenses;

[0305] The aperture 11 is located between the doublet lens and the triplet lens;

[0306] The projection lens further includes a prism 12 disposed between the tenth lens 10 and the glass plate 14 .

[0307] See also Figure 10 , Figure 10 Some optical parameters of the projection lens module are shown in Table 9 below.

[0308] Table 9

[0309]

[0310]

[0311] The aspheric parameters of the projection lens module provided in Example 5 are shown in Table 10.

[0312] Table 10

[0313]

[0314]

[0315] The optical performance of the projection lens modules provided in Examples 1 to 5 above is as follows:

[0316] See also Figure 11 , Figure 11 This is the distortion diagram of the projection lens module, with an absolute distortion value of less than 3.5%. This means that the projection lens module can maintain a good image shape and proportion during the imaging process, avoiding image distortion and deformation. This excellent distortion performance is particularly important for projection displays, ensuring that the images viewed by the audience are more realistic and natural.

[0317] See also Figure 12 , Figure 12 This is the MTF diagram of the projection lens module. The MTF is >0.55 at 93lp / mm.

[0318] from Figure 12 As can be seen in the figure, the MTF is greater than 0.55 at a spatial frequency of 93 lp / mm (line pairs / mm), indicating that the projection lens module can still maintain good imaging quality at high resolution and can clearly reproduce the details of the object. This excellent MTF performance is crucial for projection display, ensuring that the audience can see a more detailed and clear picture.

[0319] The above analysis of distortion and MTF performance demonstrates that the projection lens module of this application exhibits excellent optical performance. An absolute distortion value of less than 3.5% ensures image authenticity and naturalness; an MTF greater than 0.55 at 93 lp / mm ensures sharpness and detail resolution at high resolutions. These excellent optical properties make this lens module particularly suitable for applications requiring high image quality, such as home theaters and conference room projection.

[0320] 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.

[0321] 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: Including the following components arranged along the same optical axis: The first lens group, including a first lens (1), a second lens (2), a third lens (3), a fourth lens (4) and a doublet lens arranged in sequence along the optical axis. Among them, the first lens (1), the second lens (2) and the third lens (3) all have negative optical powers, and the fourth lens (4) and the doublet lens both have positive optical powers; The second lens group, including a triplet lens and a tenth lens (10) arranged along the optical axis. Among them, the triplet lens has a negative optical power, and the tenth lens (10) has a positive optical power; An aperture stop (11), located between the doublet lens and the triplet lens. The distance between the aperture stop (11) and the doublet lens is L1, and the distance between the aperture stop (11) and the triplet lens is L2. And L1 and L2 satisfy: 3.3 < L1 / L2 < 4; The first lens (1) is a plastic aspherical lens, and the tenth lens (10) is a glass aspherical lens. And the refractive index N1 of the first lens (1) and the refractive index N10 of the tenth lens (10) satisfy: 1.03 < N1 / N10 < 1.

1.

2. The projection lens module according to claim 1, wherein: The central thickness T' of the triplet lens satisfies 8.5% ≤ T' / TTL ≤ 10%; where TTL is the total optical length of the projection lens module.

3. The projection lens module according to claim 1 or 2, wherein: The triplet lens is composed of a seventh lens (7), an eighth lens (8) and a ninth lens (9) glued together in sequence. Among them: Both the seventh lens (7) and the ninth lens (9) have positive optical powers; The eighth lens (8) has a negative optical power; The refractive index of any one of the seventh lens (7) and the ninth lens (9) is lower than the refractive index of the eighth lens (8).

4. The projection lens module according to claim 3, wherein: The refractive indices of the seventh lens (7) and the ninth lens (9) are N1 and N2 respectively, and the refractive index of the eighth lens (8) is N3. And the triplet lens satisfies: 1.2 < N3 / (N1 + N2) < 1.

3.

5. The projection lens module according to claim 3, wherein: The triplet lens satisfies 5 < (T5 + T6) / T7 < 6, where: T5 is the central thickness of the seventh lens (7), T6 is the central thickness of the eighth lens (8), and T7 is the central thickness of the ninth lens (9).

6. The projection lens module according to claim 3, wherein: The doublet lens is composed of a fifth lens (5) and a sixth lens (6) glued together. Among them: The optical powers of the fifth lens (5) and the sixth lens (6) are opposite. One of the fifth lens (5) and the sixth lens (6) has a positive optical power, and the other has a negative optical power. And the refractive index of the lens with positive optical power is higher than the refractive index of the lens with negative optical power.

7. The projection lens module according to claim 6, wherein: The fifth lens (5) has a positive optical power and a refractive index of N5, and the sixth lens (6) has a negative optical power and a refractive index of N6. N5 and N6 satisfy: 1.03 < N5 / N6 < 1.

1.

8. The projection lens module according to claim 1, wherein: The first lens group satisfies: 0.95 < T3 / (T1 + T2) < 1.3, where: T1 is the central thickness of the first lens (1), T2 is the central thickness of the second lens (2), and T3 is the central thickness of the third lens (3).

9. The projection lens module according to claim 1 or 8, wherein: The central thickness T1 of the first lens (1) satisfies 3.3% ≤ T1 / TTL ≤ 3.7%; The central thickness T2 of the second lens (2) satisfies 1.5% ≤ T2 / TTL ≤ 1.8%; where TTL is the total optical length of the projection lens module.

10. The projection lens module according to claim 9, wherein: The sagittal height of the surface of the second lens (2) on the side away from the aperture (11) at the maximum aperture is S1, and the sagittal height of the surface on the side close to the aperture (11) at the maximum aperture is S2, and it satisfies: 3.5 < S2 / S1 < 4.

5.

11. The projection lens module according to claim 10, wherein: The angle between the tangent line of the surface of the second lens (2) on the side away from the aperture (11) at the maximum aperture and the optical axis is A1, and the angle between the tangent line of the surface on the side close to the aperture (11) at the maximum aperture and the optical axis is A2, and it satisfies: 40° < A1 - A2 < 50°, and 1.8 < A1 / A2 < 2.

3.

12. The projection lens module according to claim 1 or 8, wherein: The angle between the tangent line of the surface of the third lens (3) on the side away from the aperture (11) at the maximum aperture and the optical axis is A3, and the angle between the tangent line of the surface on the side close to the aperture (11) at the maximum aperture and the optical axis is A4, and it satisfies: 40° < A3 - A4 < 60°, and 1.6 < A3 / A4 < 2.

1.

13. The projection lens module according to claim 6, wherein: The projection lens module further includes a prism (12), a glass plate (14) and a display unit (13) which are located on the side of the tenth lens (10) away from the aperture (11) 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 satisfies: 1.5 < TTL / D1 < 1.

9.

14. The projection lens module according to claim 13, wherein: The effective focal lengths of the respective lenses in the projection lens are: The effective focal length of the first lens (1) is F1, -32 mm ≤ F1 ≤ -24 mm; The effective focal length of the second lens (2) is F2, -19 mm ≤ F2 ≤ -14 mm; The effective focal length of the third lens (3) is F3, -19 mm ≤ F3 ≤ -14 mm; The effective focal length of the fourth lens (4) is F4, 25 mm ≤ F4 ≤ 36 mm; The effective focal length of the doublet lens is F', 17 mm ≤ F' ≤ 25 mm; The effective focal length of the triplet lens is F'', -80 mm ≤ F'' ≤ -55 mm; The effective focal length of the tenth lens (10) is F10, 9 mm ≤ F10 ≤ 14 mm; The second lens (2) to the ninth lens (9) are glass spherical lenses.

15. The projection lens module according to claim 14, wherein: The focal length of the projection lens module is 2.83 mm, the projection ratio TR is 0.5, the relative aperture is 1 / 1.699, the Offset is 140%, the pixel size is 5.4 μm, the field angle is 55° to 59°, the image plane size is 8.5 mm to 9.1 mm, and the working wavelength range is 455 nm to 630 nm.

16. A projection device, characterized in that: Comprising: A housing; And The projection lens module according to any one of claims 1 - 15.

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