Projection lens module and projection equipment

Abstract

The embodiment of the invention provides a projection lens module and projection equipment. Wherein the projection lens module comprises a first lens group, a diaphragm and a second lens group which are arranged along the same optical axis; the first lens group comprises a first lens, a second lens, a third lens, a fourth lens and a first doublet lens which are sequentially arranged along the optical axis; the second lens group comprises a second doublet lens, a ninth lens, a third doublet lens and a twelfth lens which are sequentially arranged along the optical axis; the diaphragm is located between the first doublet lens and the second doublet lens; wherein the total center thickness T'of all doublet lenses included in the projection lens and the optical total length TTL of the projection lens module meet the condition that T ' / TTL is larger than or equal to 7% and smaller than or equal to 11%.

Description

Technical Field

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

[0002] With the continuous development of projection technology, the demand for home projection devices is increasing day by day. Traditional projection devices usually use long - focal - length projection lenses, and the projection device needs to keep a relatively long distance from the projection wall, which not only occupies a large amount of space but also limits the placement position of the projection device. In addition, during the projection process of traditional projection devices, there should be no obstacles between the projector and the projection wall, otherwise it will affect the projection effect and bring inconvenience to users.

[0003] To solve the above problems, short - focal - length projection technology has emerged. Short - focal - length projection devices can project a large image at a relatively short distance, and the influence of obstacles between the projection device and the projection wall on the projection effect is relatively small. However, the design of short - focal - length and ultra - short - focal - length projection lenses is more difficult. Especially while ensuring high optical performance, it is also necessary to meet the requirements of a small projection ratio and a large offset.

[0004] Existing short - focal - length projection lenses usually use more lenses to achieve high optical performance, but this will lead to a larger volume and higher cost of the projection lens. Therefore, how to reduce the number of lenses, reduce the volume and cost of the projection lens while ensuring optical performance has become an important challenge in the design of short - focal - length projection lenses. Summary of the Invention

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

[0006] In a first aspect, the embodiments of the present application provide a projection lens module, which includes, arranged along the same optical axis:

[0007] A first lens group, including a first lens, a second lens, a third lens, a fourth lens, and a first doublet lens arranged in sequence along the optical axis;

[0008] A second lens group, including a second doublet lens, a ninth lens, a third doublet lens, and a twelfth lens arranged in sequence along the optical axis;

[0009] An aperture stop, located between the first doublet lens and the second doublet lens;

[0010] Wherein, the total central thickness T' of all doublet lenses included in the projection lens satisfies: 7% ≤ T' / TTL ≤ 11% with respect to the optical total length TTL of the projection lens module.

[0011] Optionally, in the first lens group: the first lens and the second lens have negative optical powers, and the third lens, the fourth lens, and the first doublet lens all have positive optical powers;

[0012] In the second lens group: the second doublet lens has a negative optical power, and the ninth lens, the third doublet lens, and the twelfth lens all have positive optical powers.

[0013] Optionally, in the first lens group, the third lens and the fourth lens both have positive optical powers, and the following specific relationships are satisfied among the central thickness T3 of the third lens, the central thickness T4 of the fourth lens, and the overall optical length TTL of the projection lens module:

[0014] 4% ≤ T3 / TTL ≤ 4.8%;

[0015] 3.5% ≤ T4 / TTL ≤ 4.2%.

[0016] Optionally, the first doublet lens includes a fifth lens and a sixth lens that are cemented together;

[0017] The fifth lens and the sixth lens have opposite optical powers, the fifth lens has a negative optical power, the sixth lens has a positive optical power, and the refractive index N6 of the sixth lens is higher than the refractive index N5 of the fifth lens.

[0018] Optionally, the second doublet lens includes a seventh lens and an eighth lens that are cemented together, the seventh lens and the eighth lens have opposite optical powers, the seventh lens has a positive optical power, and the eighth lens has a negative optical power;

[0019] The third doublet lens includes a tenth lens and an eleventh lens that are cemented together, the tenth lens and the eleventh lens have opposite optical powers, the tenth lens has a negative optical power, and the eleventh lens has a positive optical power;

[0020] Among them, the refractive index N7 of the seventh lens is lower than the refractive index N8 of the eighth lens, and the refractive index N11 of the eleventh lens is lower than the refractive index N10 of the tenth lens.

[0021] Optionally, in the second lens group, the seventh lens and the eleventh lens have positive optical powers, and the eighth lens and the tenth lens have negative optical powers, then it satisfies: 3.3 < (T7 + T11) / (T8 + T10) < 4, where T7 is the central thickness of the seventh lens, T8 is the central thickness of the eighth lens, T10 is the central thickness of the tenth lens, and T11 is the central thickness of the eleventh lens.

[0022] Optionally, in the first lens group, the central thickness of the first lens is T1, the central thickness of the second lens is T2, the central thickness of the third lens is T3, and the central thickness of the fourth lens is T4. Among them, the ratio between the sum of the central thicknesses of the third lens and the fourth lens (T3 + T4) and the sum of the central thicknesses of the first lens and the second lens (T1 + T2) satisfies: 2 < (T3 + T4) / (T1 + T2) < 2.7.

[0023] Optionally, for the twelfth lens, the sagittal height of the surface close to the aperture stop at the maximum aperture is S1, and the sagittal height of the surface far from the aperture stop at the maximum aperture is S2. The ratio between S2 and S1 is 1.3 < S2 / S1 < 1.8.

[0024] Optionally, the air gap between the aperture stop and the second doublet lens is L1, and the air gap between the aperture stop and the first doublet lens is L2. And the following is satisfied between L1 and L2: 100 < TTL / (L1 + L2) < 150.

[0025] Optionally, the optical power of the third lens is positive. The angle between the tangent of the lens surface of the third lens close to the aperture stop at the maximum aperture and the optical axis is A1, and the angle between the tangent of the lens surface of the third lens far from the aperture stop at the maximum aperture and the optical axis is A2. A1 and A2 satisfy the following relationship:

[0026] 15° < A2 - A1 < 35°; and

[0027] 1.35 < A2 / A1 < 1.55.

[0028] Optionally, the second lens has a negative optical power. The angle between the tangent of the lens surface of the second lens close to the aperture stop at the maximum aperture and the optical axis is A3, and the angle between the tangent of the lens surface of the second lens far from the aperture stop at the maximum aperture and the optical axis is A4. The following is satisfied between A3 and A4: 30° < A4 - A3 < 45°.

[0029] Optionally, the projection lens module further includes a galvanometer, a prism, a glass plate, and a display unit that are sequentially arranged along the optical axis on the side of the twelfth lens far from the aperture stop;

[0030] The projection lens further includes a reflection element, which is located on the side of the first lens far from the aperture stop and is used to reflect the light for projection imaging to the imaging surface;

[0031] The ratio of the overall optical length TTL of the projection lens module to the maximum aperture D1 of the lens in the projection lens module satisfies: 4 < TTL / D1 < 4.7.

[0032] Optionally, the effective focal lengths of the lenses in the projection lens module are as follows:

[0033] The effective focal length of the first lens is F1, and -42 mm ≤ F1 ≤ -34 mm;

[0034] The effective focal length of the second lens is F2, and -56 mm ≤ F2 ≤ -49 mm;

[0035] The effective focal length of the third lens is F3, and 120 mm ≤ F3 ≤ 150 mm;

[0036] The effective focal length of the fourth lens is F4, and 50 mm ≤ F4 ≤ 72 mm;

[0037] The effective focal length of the first doublet lens is F', and 40 mm ≤ F' ≤ 52 mm;

[0038] The effective focal length of the second doublet lens is F'', and -42 mm ≤ F'' ≤ -33 mm;

[0039] The effective focal length of the ninth lens is F9, and 20 mm ≤ F9 ≤ 27 mm;

[0040] The effective focal length of the third doublet lens is F''', and 50 mm ≤ F''' ≤ 80 mm;

[0041] The effective focal length of the twelfth lens is F12, and 50 mm ≤ F12 ≤ 65 mm;

[0042] The first lens and the fourth lens are plastic aspherical lens elements, the ninth lens is a glass aspherical lens element, and the remaining lenses are all glass spherical lenses;

[0043] The reflection element is an aspherical reflector bowl.

[0044] Optionally, the focal length of the projection lens module is 1.444 mm, the projection ratio TR is 0.23, the relative aperture is 1 / 1.71, Offset is 140%, the pixel size is 5.4 μm, the working wavelength band is 455 nm to 630 nm, the field of view angle is 74° to 78°, and the image plane size is 11.5 mm to 11.9 mm.

[0045] In a second aspect, an embodiment of the present application provides a projection device, which includes:

[0046] A housing; and

[0047] The projection lens as described in the second aspect.

[0048] The beneficial effects of the present application are:

[0049] The projection lens module according to the embodiments of the present application reduces the number of lenses on the premise of ensuring high optical performance, thereby effectively reducing the volume and production cost of the projection lens module. Moreover, the projection lens module meets the dual requirements of a small projection ratio and a large offset. This design enables the projection lens module to project a relatively wide and clear projection image within an extremely short projection distance (such as within the range of 1.4 mm to 1.5 mm, and the more accurate projection distance is 1.444 mm), providing convenience for scenarios with limited space.

[0050] In the present application, by controlling the number of doublet lenses in the projection lens module and setting the proportional relationship between the total central thickness T' of all doublet lenses and the optical total length TTL of the projection lens module (controlled between 7% and 11%), the chromatic aberration of the projection lens module is corrected, and thus the overall imaging quality is significantly improved. Regarding the setting of this thickness ratio range, it not only ensures that the projection lens module reaches an excellent level in chromatic aberration correction, but also takes into account the superiority of optical performance and the compactness of the overall structure, balancing the optical performance and volume of the projection lens module, enabling it to achieve excellent effects of short-distance and large-size projection images while ensuring high-quality imaging.

[0051] Other features and advantages of the present specification will become clear through the following detailed description of the exemplary embodiments of the present specification with reference to the accompanying drawings. Brief Description of the Drawings

[0052] The drawings incorporated in the specification and constituting a part of the specification illustrate the embodiments of the present specification and, together with the description thereof, are used to explain the principles of the present specification.

[0053] Figure 1 Schematic diagram of the usage state of the projection lens module provided by the embodiments of the present application;

[0054] Figure 2 Schematic diagram of an optical architecture of the projection lens module provided by the embodiments of the present application (excluding reflection elements);

[0055] Figure 3 Schematic diagram of a partial structure of the third lens provided by the embodiments of the present application;

[0056] Figure 4 Schematic diagram of a partial structure of the second lens provided by the embodiments of the present application;

[0057] Figure 5 Schematic diagram of the structure and optical path of the projection lens module provided by Embodiment 1 of the present application (including reflection elements);

[0058] Figure 6The structure and optical path diagram of the projection lens module provided in Embodiment 2 of the present application (excluding reflection elements);

[0059] Figure 7 The structure and optical path diagram of the projection lens module provided in Embodiment 3 of the present application (excluding reflection elements);

[0060] Figure 8 The structure and optical path diagram of the projection lens module provided in Embodiment 4 of the present application (excluding reflection elements);

[0061] Figure 9 The structure and optical path diagram of the projection lens module provided in Embodiment 5 of the present application (excluding reflection elements);

[0062] Figure 10 The distortion diagram of the projection lens module provided in the embodiments of the present application;

[0063] Figure 11 The MTF diagram of the projection lens module provided in the embodiments of the present application.

[0064] Description of reference numerals:

[0065] 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. Eleventh lens; 12. Twelfth lens; 13. Diaphragm; 14. Galvo; 15. Prism; 16. Reflection element; 17. Glass plate; 18. Display unit. Detailed implementation manners

[0066] Now, various exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0067] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present application and its application or use.

[0068] Technologies and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies and devices should be regarded as part of the specification.

[0069] In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0070] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it will not be discussed further in subsequent figures.

[0071] 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.

[0072] According to an embodiment of the present application, a projection lens module is provided. Refer to Figure 2 and Figure 5 , the projection lens module includes: a first lens group, a second lens group, and a diaphragm 13 arranged 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 first doublet lens arranged in sequence along the optical axis; the second lens group includes a second doublet lens, a ninth lens 9, a third doublet lens, and a twelfth lens 12 arranged in sequence along the optical axis; the diaphragm 13 is located between the first doublet lens and the second doublet lens; wherein, the total central thickness T' of all the doublet lenses included in the projection lens satisfies: 7% ≤ T' / TTL ≤ 11% with respect to the optical total length TTL of the projection lens module.

[0073] The projection lens module provided by the embodiments of the present application, refer to Figure 2 and Figure 5 , its main components include a projection lens and a display unit 18. Among them, the projection lens includes the above-mentioned first lens group, second lens group, and the diaphragm 13 located between the two lens groups (the position of the diaphragm 13 is fixed, that is, the distances between the diaphragm 13 and the lenses on both sides are fixed). The projection lens is located on the light-emitting optical path of the display unit 18, and the projection lens is responsible for receiving the light emitted from the display unit 18 (these lights are dedicated to projection display), and performing a series of optical processes on these lights. Through this series of optical actions, the light emitted by the display unit 18 can be guided and projected onto the imaging surface, and finally a clear projection image is presented.

[0074] Refer to Figure 1 and Figure 5 , the projection light processed by the projection lens module will be projected onto the imaging surface (such as the projection wall surface in Figure 5 ) through the reflection element 16 shown on the rightmost side in Figure 1 . In this process, the projection lens module exhibits excellent optical performance, including characteristics such as high definition, high contrast, and low distortion, which together ensure the high-quality presentation of the projection image.

[0075] Refer to Figure 2, the projection lens module provided by the embodiment of the present application, wherein the projection lens includes two lens groups: the first lens group and the second lens group; wherein, the first lens group (located on the right side in Figure 2 is farther from the display unit 18 than the second lens group; and the second lens group (located on the left side in Figure 2 ) is arranged closer to the display unit 18. Moreover, a diaphragm 13 is provided between the first lens group and the second lens group to optimize the light transmission and imaging effect.

[0076] Regarding the first lens group provided in the embodiment of the present application, the specific description is as follows.

[0077] The first lens group is one of the components of the entire projection lens module. Refer to Figure 2 and Figure 5 , the structural configuration of the first lens group includes the first lens 1, the second lens 2, the third lens 3, the fourth lens 4 and the first doublet lens. That is, the first lens group includes four independent lenses and one doublet lens, a total of six optical lenses.

[0078] Specifically, the first lens group realizes the reasonable regulation of light through the cooperation between its six internal optical lenses. Among them, the combination of the first lens 1 to the fourth lens 4 and the first doublet lens not only corrects the aberration that may occur during the light transmission process, but also controls the propagation direction of the light to ensure that the light can propagate along the predetermined path. At the same time, the first lens group also optimizes the light distribution and intensity, so that the light has good uniformity and appropriate intensity before reaching the subsequent projection imaging. The first lens group lays the foundation for the subsequent imaging process and ensures that the projection lens module can output high-quality and clear projection images.

[0079] Regarding the second lens group provided in the embodiment of the present application, the specific description is as follows.

[0080] The second lens group is another component of the projection lens, and its composition includes the second doublet lens, the ninth lens 9, the third doublet lens and the twelfth lens 12. That is, the second doublet lens includes two doublet lenses and two independent lenses, a total of six lenses.

[0081] The second lens group adopts a specific optical design, and each lens is designed and optimized to ensure that the light can obtain the best optical effect when passing through a series of lenses in the second lens group. In particular, the combined use of two doublet lenses and two independent lenses can not only effectively correct the aberration that may occur during the light transmission process, but also optimize the focal point of the light, which is beneficial to making the projection image clearer.

[0082] The diaphragm 13 is located between the first lens group and the second lens group. Specifically, the diaphragm 13 is located between the first doublet lens in the first lens group and the second doublet lens in the second lens group. The diaphragm 13 can be used to limit the amount of light passing through, control the incident angle and range of light, so as to improve the contrast and clarity of the projection screen.

[0083] In the projection lens module provided by the embodiment of the present application, both sides of the diaphragm 13 are designed as doublet lenses (i.e., the first doublet lens and the second doublet lens). This design has the following advantages:

[0084] (1) It can optimize the optical path symmetry and reduce aberration. The design that both sides of the diaphragm 13 are doublet lenses can optimize the symmetry of the optical path, making the propagation path of light more uniform before and after passing through the diaphragm 13 and reducing the generation of aberration. This symmetry design helps to correct spherical aberration, coma and astigmatism, thereby improving the imaging quality.

[0085] (2) Improve the chromatic aberration correction ability. Chromatic aberration is an aberration caused by different refractive indices of light with different wavelengths when passing through a lens, which will cause colored fringes to appear at the imaging edge and affect the imaging quality. Each doublet lens can effectively correct chromatic aberration through the combination of positive and negative lenses. The design that both sides of the diaphragm 13 are doublet lenses can further enhance the chromatic aberration correction ability and ensure that the chromatic aberration of light before and after passing through the diaphragm 13 is fully corrected.

[0086] (3) Enhance the stability of the entire projection lens. The diaphragm 13 is located in the middle of the projection lens, and the doublet lenses on both sides of the diaphragm 13 can ensure that the propagation path of light is more stable before and after passing through the diaphragm 13, reducing the deviation and scattering of light.

[0087] The projection lens module provided by the embodiment of the present application includes three doublet lenses; among them, one doublet lens is located in the first lens group, and the other two doublet lenses are located in the second lens group. The relationship between the total central thickness T' of these three cemented lenses and the optical total length TTL of the projection lens module is 7% ≤ T' / TTL ≤ 11%. The design of this proportional relationship is to optimize the volume of the projection lens module while ensuring the optical performance. Specifically:

[0088] First of all, each doublet lens in the projection lens module is composed of two lenses cemented together, which can effectively correct aberrations such as chromatic aberration and spherical aberration, and improve the imaging quality of the projection lens module. That is to say, in the present application, the configuration of three doublet lenses makes the optical performance of the entire projection lens module significantly improved.

[0089] The proportional relationship between T' (the total central thickness of all doublet lenses in the projection lens module) and TTL (the optical total length of the projection lens module) further optimizes the performance of the projection lens module. This proportional relationship ensures that the proportion of all doublet lenses in the overall structure of the projection lens module is appropriate, neither too large nor too small. If the proportion is too large, it may cause the formed projection lens module to be too heavy and may introduce additional aberrations. If the proportion is too small, the correction effect of the doublet lenses may not be fully exerted, affecting the imaging quality of the projection lens module.

[0090] Furthermore, the proportional relationship of 7% ≤ T' / TTL ≤ 11% ensures that the projection lens module has excellent performance in the following aspects:

[0091] (1) Chromatic aberration correction: The main function of the doublet lens is to correct chromatic aberration. By reasonably configuring the thickness and position of the three doublet lenses and maintaining an appropriate ratio between T' and TTL, the projection lens module can effectively correct chromatic aberration, making the colors of the projection image more real and natural.

[0092] If the total thickness of all doublet lenses is too small (T' / TTL < 7%), chromatic aberration cannot be fully corrected, resulting in a decline in imaging quality.

[0093] If the total thickness of all doublet lenses is too large (T' / TTL > 11%), although chromatic aberration can be better corrected, it will increase the volume and weight of the projection lens, which is not conducive to the compact design of the projection lens and will directly affect the volume of the entire projection lens module.

[0094] (2) Improvement of optical performance: The proportional relationship between the total central thickness T' of all doublet lenses in the projection lens module and the optical total length TTL of the projection lens module directly affects the optical performance of the projection lens module. By reasonably designing this ratio, it can be ensured that the projection lens module maintains good imaging quality while correcting chromatic aberration and spherical aberration.

[0095] Specifically, the proportional relationship between the total central thickness T' of all doublet lenses and the optical total length TTL of the projection lens module affects the chromatic aberration correction ability, spherical aberration correction ability, and astigmatism correction ability of the entire projection lens module. By controlling this ratio between 7% and 11%, it can be ensured that the projection lens module achieves the best performance in these aspects.

[0096] (3) Optimization of the volume and weight of the projection lens module: By controlling the ratio of the total central thickness T' of all doublet lenses to the optical total length TTL of the projection lens module, the volume and weight of the projection lens module can be minimized while ensuring optical performance.

[0097] For example, in the projection lens module, the total thickness T' of the three doublet lenses is 17.5 mm to 27.5 mm (assuming that the overall optical length TTL of the projection lens module is 250 mm). This design within this range can ensure that the doublet lenses achieve the best effect in correcting chromatic aberration and spherical aberration, while minimizing the volume and weight of the projection lens.

[0098] Thus, in this application, by controlling the number of doublet lenses in the projection lens and the ratio between the total central thickness T' of all doublet lenses and the overall optical length TTL of the entire projection lens module (ensuring it is between 7% and 11%), the correction of chromatic aberration of the projection lens module is achieved, significantly improving the imaging quality. The setting of this thickness ratio range not only ensures excellent performance in chromatic aberration correction of the projection lens module, but also takes into account the superiority of optical performance and the compactness of the overall structure, achieving a balance between the performance and volume of the projection lens module.

[0099] One of the design intents of the projection lens module provided in the embodiments of this application is to achieve an ultra-short focal length projection effect. Through a specific combination of optical elements and optical parameter settings, the focal length of the projection lens module can be between 1.4 mm and 1.5 mm (specifically, it can be accurate to 1.444 mm), the projection ratio reaches 0.23, and the Offset is 140%, which exceeds the performance of traditional projection devices. This design reduces the occupation of the projection space and also avoids the problem of the projection screen being blocked by the projector body.

[0100] Due to the adoption of the ultra-short focal length projection technology, users can enjoy a large-screen viewing experience in a smaller space without worrying about the projection distance and obstacles. This not only improves the viewing comfort of users, but also expands the usage scenarios and flexibility of the projector. In addition, the projection lens module provided in the embodiments of this application can provide a high-definition projection screen and excellent color reproduction ability, further enhancing the viewing experience of users.

[0101] In some examples of this application, refer to Figure 2 and Figure 5 , in the first lens group: the first lens 1 and the second lens 2 have negative optical power, and the third lens 3, the fourth lens 4, and the first doublet lens all have positive optical power; in the second lens group: the second doublet lens has negative optical power, and the ninth lens 9, the third doublet lens, and the twelfth lens 12 all have positive optical power.

[0102] It should be noted that Figure 5 is the overall structural schematic diagram of the projection lens module of this application, in which the reflection element 16 on the far right (on the side away from the display unit 18) is introduced. And Figure 2Shown is the layout of the projection lens and the display unit 18 in the projection lens module.

[0103] In the example provided in this application, refer to Figure 2 and Figure 5 , the projection lens module includes two lens groups: the first lens group and the second lens group, and the optical power configurations of the individual lenses and doublets in these two lens groups have been specially designed and can have a significant impact on the optical performance of the entire projection lens module.

[0104] Regarding the design of the optical power distribution in the first lens group:

[0105] The first lens group includes six lenses, namely: the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 5 and the sixth lens 6 (forming the first doublet).

[0106] Among them, the optical powers of the first lens 1 and the second lens 2 are both negative. The negative optical power design helps to correct spherical aberration. The optical powers of the third lens 3 and the fourth lens 4 are positive. The lenses with positive optical powers have the function of converging light. In the first lens group, the positive optical power design of the third lens 3 and the fourth lens 4 helps to correct astigmatism and field curvature. The fifth lens 5 and the sixth lens 6 form the first doublet, and the optical power of the first doublet is positive, further enhancing the light converging ability and helping to correct chromatic aberration and spherical aberration.

[0107] Regarding the design of the optical power distribution of the second lens group:

[0108] The second lens group includes six lenses, namely: the seventh lens 7 to the twelfth lens 12; among them, the seventh lens 7 and the eighth lens 8 form the second doublet, and the tenth lens 10 and the eleventh lens 11 form the third doublet. Among them, the optical power of the second doublet is negative, and the negative optical power design of the second doublet helps to correct chromatic aberration and aberration. The optical power of the ninth lens 9 is positive, and the positive optical power design of the ninth lens 9 helps to converge light, improve the light utilization efficiency, and at the same time correct astigmatism and field curvature. In addition, the optical powers of the third doublet and the twelfth lens 12 are both positive.

[0109] According to an example of the present application, by using a combination of a negative lens - negative lens - positive lens - positive lens - positive doublet lens in the first lens group and a combination of a negative doublet lens - positive lens - positive doublet lens - positive lens in the second lens group, the optical power design of the projection lens of the present application can effectively correct aberrations such as chromatic aberration and spherical aberration, and improve the clarity and contrast of the projection image. Under such an optical power configuration, the projection lens module of the present application can maintain excellent imaging quality at a relatively wide field of view (74° to 78°), meeting the requirements of ultra-short throw projection devices.

[0110] All the negative lenses in the first lens group and the second lens group help to broaden the field of view range, enabling the projection lens module to capture more extensive picture information. All the positive lenses in the first lens group and the second lens group effectively enhance the light converging ability, improving the brightness and uniformity of the projection image.

[0111] In some examples of the present application, referring to Figure 2 and Figure 5 , in the first lens group, both the third lens 3 and the fourth lens 4 have positive optical power, and the following specific relationships are satisfied among the central thickness T3 of the third lens 3, the central thickness T4 of the fourth lens 4, and the optical total length TTL of the projection lens module: 4% ≤ T3 / TTL ≤ 4.8%, 3.5% ≤ T4 / TTL ≤ 4.2%.

[0112] In the first lens group, both the third lens 3 and the fourth lens 4 have positive optical power and can converge light. Moreover, by controlling the central thicknesses T3 and T4 of the third lens 3 and the fourth lens 4 within a specific proportion range of the optical total length TTL of the entire projection lens module (i.e., T3 / TTL is 4% to 4.8% and T4 / TTL is 3.5% to 4.2%), it can be ensured that these two lenses play a better role of positive optical power in the entire projection lens module, such as effectively correcting aberrations.

[0113] According to the control conditions provided in this example of the present application, it helps to improve the imaging quality of the projection lens module. Specifically:

[0114] The design of the central thicknesses of the third lens 3 and the fourth lens 4 helps to correct aberrations such as spherical aberration and coma in the projection lens module. Spherical aberration is an aberration caused by different focusing points of light rays at the edge and center of the lens. Coma is an aberration caused by oblique incidence of light rays. In this example provided by the present application, by reasonably controlling the proportion range of the central thicknesses of the third lens 3 and the fourth lens 4, these aberrations can be reduced, thereby improving the imaging quality.

[0115] Moreover, the design of the central thickness ratio of the third lens 3 and the fourth lens 4 can also assist in chromatic aberration correction to a certain extent, further improving the imaging clarity and color reproduction.

[0116] This example provided by the present application can also optimize the optical structure compactness of the projection lens module. By controlling the central thicknesses of the third lens 3 and the fourth lens 4 within a specific ratio range of the total optical length TTL of the module (T3 / TTL is 4% - 4.8%, T4 / TTL is 3.5% - 4.2%), the structural compactness of the projection lens module can be optimized while ensuring optical performance. This design achieves an optimal balance between the total length (TTL) of the projection lens module and the thickness of a single lens, thereby reducing the volume and weight of the projection lens module.

[0117] Ultra-short focal length projection devices need to project a large image within a limited space. In the present application, the design of the central thicknesses of the third lens 3 and the fourth lens 4 makes the entire projection lens module more compact, which is very suitable for this application scenario.

[0118] The design of the central thicknesses of the third lens 3 and the fourth lens 4 not only affects the optical performance of the lenses but also affects their mechanical strength. By controlling their central thicknesses within a reasonable range, it can be ensured that these two lenses have sufficient mechanical strength in the projection lens, thereby improving the stability of the projection lens and thus the stability of the projection lens module.

[0119] In addition, the thickness of the lens directly affects the material usage. By controlling the central thicknesses of the third lens 3 and the fourth lens 4 within a reasonable range, the material usage can be appropriately reduced, and thus the manufacturing cost can be lowered.

[0120] The ratio relationship between the central thicknesses of the third lens 3 and the fourth lens 4 and the total optical length TTL of the projection lens module (4% ≤ T3 / TTL ≤ 4.8%, 3.5% ≤ T4 / TTL ≤ 4.2%) is an important parameter of the projection lens module in the present application. By reasonably designing this ratio, the structural compactness, stability, and production cost of the module can be optimized while ensuring the optical performance of the module. Through this design, the projection lens module can reduce the number of lenses, lower the volume and cost of the projection lens, and meet the requirements of a small projection ratio and a large offset while ensuring high optical performance.

[0121] In some examples of the present application, refer to Figure 2 and Figure 5, the first doublet lens includes a fifth lens 5 and a sixth lens 6 that are glued together; the fifth lens 5 and the sixth lens 6 have opposite optical powers, the fifth lens 5 has a negative optical power, the sixth lens 6 has a positive optical power, and the refractive index N6 of the sixth lens 6 is higher than the refractive index N5 of the fifth lens 5.

[0122] In the first lens group, a first doublet lens is designed. The first doublet lens includes a fifth lens 5 and a sixth lens 6. The optical powers of the fifth lens 5 and the sixth lens 6 are opposite, that is, one lens has a positive optical power and the other lens has a negative optical power. This opposite optical power configuration helps to correct aberrations, especially chromatic aberration, because light rays of different wavelengths will have their refraction paths compensated to different degrees when passing through lenses with opposite optical powers.

[0123] In the example of the present application, the optical powers of the fifth lens 5 and the sixth lens 6 are opposite. Among them, the refractive index of the sixth lens 6 with positive optical power is higher than that of the fifth lens 5 with negative optical power. This design can effectively correct chromatic aberration. Specifically, the combination of the positive and negative optical powers of these two lenses can balance the propagation paths of light rays of different wavelengths, enabling them to converge to the same point, thereby reducing chromatic aberration.

[0124] This design in the example of the present application enables the first doublet lens to achieve the best effect in correcting chromatic aberration and aberrations, while optimizing the structural compactness and stability of the projection lens module.

[0125] In one example, in the first doublet lens: the refractive index of the sixth lens 6 with positive optical power is 1.7 to 1.78, and the refractive index of the fifth lens 5 with negative optical power is 1.59 to 1.64. This example describes the specific range of the refractive indices of the two lenses in the first doublet lens.

[0126] Regarding the refractive index of the sixth lens 6 with positive optical power: it is designed to be between 1.7 and 1.78. The refractive index materials within this range have a relatively high light refraction ability, which helps to enhance the light converging effect of this lens, thereby improving the clarity and contrast of the image during the imaging process.

[0127] Regarding the refractive index of the fifth lens 5 with negative optical power: it is designed to be between 1.59 and 1.64. Compared with the above-mentioned sixth lens 6 with positive optical power, the refractive index of the fifth lens 5 with negative optical power is slightly lower, but it is still sufficient to achieve an effective light divergence effect. This refractive index difference makes the doublet lens more flexible and efficient in correcting chromatic aberration and aberrations. At the same time, these refractive index selections do not increase the production cost.

[0128] In some examples of the present application, seeFigure 2 and Figure 5 The second doublet lens includes a seventh lens 7 and an eighth lens 8 that are cemented together. The seventh lens 7 and the eighth lens 8 have opposite optical powers. The seventh lens 7 has a positive optical power, and the eighth lens 8 has a negative optical power. The third doublet lens includes a tenth lens 10 and an eleventh lens 11 that are cemented together. The tenth lens 10 and the eleventh lens 11 have opposite optical powers. The tenth lens 10 has a negative optical power, and the eleventh lens 11 has a positive optical power. Among them, the refractive index N7 of the seventh lens 7 is lower than the refractive index N8 of the eighth lens 8, and the refractive index N11 of the eleventh lens 11 is lower than the refractive index N10 of the tenth lens 10.

[0129] In the example provided by this application, the second doublet lens is composed of a seventh lens 7 and an eighth lens 8 that are cemented together, and the third doublet lens is composed of a tenth lens 10 and an eleventh lens 11 that are cemented together. The designs of these two doublet lenses both have the following characteristics:

[0130] (1) Opposite optical powers: The seventh lens 7 and the eighth lens 8 have opposite optical powers, and the tenth lens 10 and the eleventh lens 11 also have opposite optical powers. That is, in each doublet lens, one lens has a positive optical power, and the other lens has a negative optical power.

[0131] (2) Refractive index relationship: In these two doublet lenses, the refractive index of the lens with positive optical power is lower than the refractive index of the lens with negative optical power.

[0132] In the example of this application, both the second doublet lens and the third doublet lens adopt a combination of a positive lens and a negative lens, and adopt a specific refractive index relationship configuration. Such a design can balance the propagation paths of light rays of different wavelengths, thereby reducing chromatic aberration. At the same time, spherical aberration and coma correction can be achieved. In addition, the optical designs of the second doublet lens and the third doublet lens can also correct astigmatism and field curvature, so that the light rays can be evenly distributed after passing through the projection lens, improving the clarity and color reproduction of the image.

[0133] The structural design of the doublet lens makes its optical performance more stable, and can effectively resist the influence of temperature changes and mechanical vibrations on the entire projection lens module.

[0134] The design of the opposite optical powers of the seventh lens 7 and the eighth lens 8, and the tenth lens 10 and the eleventh lens 11 can further enhance the stability of the projection lens module, ensuring good imaging quality under various environmental conditions.

[0135] In this design of the present application example, the second doublet lens and the third doublet lens achieve the best effect in correcting chromatic aberration and spherical aberration, while optimizing the structural compactness and stability of the projection lens.

[0136] In some examples of the present application, in the second lens group, the seventh lens 7 and the eleventh lens 11 have positive optical powers, and the eighth lens 8 and the tenth lens 10 have negative optical powers, and the following is satisfied: 3.3 < (T7 + T11) / (T8 + T10) < 4, where T7 is the central thickness of the seventh lens 7, T8 is the central thickness of the eighth lens 8, T10 is the central thickness of the tenth lens 10, and T11 is the central thickness of the eleventh lens 11.

[0137] The second lens group of the present application includes two doublet lenses. By controlling the ratio of the central thicknesses of all positive lenses and all negative lenses in these two doublet lenses, chromatic aberration generated when light of different wavelengths passes through these two doublet lenses can be more effectively balanced and corrected, thereby improving the imaging quality.

[0138] The combined use of positive lenses and negative lenses helps to control spherical aberration, such as spherical aberration, chromatic aberration, and astigmatism. By adjusting their thickness ratio, these spherical aberrations can be further optimized to ensure image clarity and contrast.

[0139] The control conditions proposed in this example of the present application help to optimize the optical performance of the entire projection lens. By controlling the ratio of the central thicknesses of lenses with different optical powers, it is possible to ensure that the lens has sufficient optical resolution, contrast, and color reproducibility while maintaining a small projection ratio and a large offset.

[0140] Under the condition of satisfying the above conditions, the design of the projection lens module can improve the optical efficiency while maintaining compactness. This is particularly important for application scenarios with limited space such as home projectors.

[0141] By controlling the thickness ratio of the seventh lens 7 and the eleventh lens 11 (both with positive optical powers) to the eighth lens 8 and the tenth lens 10 (both with negative optical powers) in the second lens group to be between 3.3 and 4, chromatic aberration can be effectively corrected, spherical aberration can be controlled, and the optical performance of the entire projection lens can be optimized. This design condition is crucial for achieving an ultra-short focal projection effect and also helps to maintain the compactness and optical efficiency of the projection lens module.

[0142] In one example, in the second doublet lens and the third doublet lens: the refractive indices of the seventh lens 7 and the eleventh lens 11 with positive optical power range from 1.5 to 1.56, and the refractive indices of the eighth lens 8 and the tenth lens 10 with negative optical power range from 1.82 to 1.92. In this example, specific range descriptions are given for the refractive indices of the positive and negative lenses in the second doublet lens and the third doublet lens.

[0143] Regarding the refractive indices of the seventh lens 7 and the eleventh lens 11 with positive optical power: they are designed to be between 1.5 and 1.56. This refractive index range corresponds to some low-refractive-index optical materials with good transmittance and low dispersion characteristics.

[0144] Regarding the refractive indices of the eighth lens 8 and the tenth lens 10 with negative optical power: they are designed to be between 1.82 and 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 help correct chromatic aberration.

[0145] Combining high-refractive-index negative-power lenses with low-refractive-index positive-power lenses can make more refined adjustments to the refraction paths of light of different wavelengths, thereby reducing color distortion and improving the color reproduction and clarity of the image.

[0146] High-refractive-index negative-power lenses can achieve a thinner thickness while maintaining the same optical power, which helps reduce the volume and weight of the entire projection lens module and enables a more compact design.

[0147] Materials with different refractive indices have different thermal expansion coefficients and mechanical properties. By reasonably matching these materials in this application, the change in optical properties caused by temperature changes or mechanical stress can be reduced, enhancing the stability of the entire projection lens module.

[0148] In some examples of this application, in the first lens group, the central thickness of the first lens 1 is T1, the central thickness of the second lens 2 is T2, the central thickness of the third lens 3 is T3, and the central thickness of the fourth lens 4 is T4. Among them, the ratio between the sum of the central thicknesses of the third lens 3 and the fourth lens 4 (T3 + T4) and the sum of the central thicknesses of the first lens 1 and the second lens 2 (T1 + T2) satisfies: 2 < (T3 + T4) / (T1 + T2) < 2.7.

[0149] By adjusting the ratio of the central thicknesses of the positive lenses (both the third lens 3 and the fourth lens 4 have positive optical powers) to the negative lenses (both the first lens 1 and the second lens 2 have negative optical powers), it is possible to more effectively balance and correct the chromatic aberration generated when light of different wavelengths passes through the lens. Moreover, the reasonable combination of the positive lenses and the negative lenses also helps to control other aberrations, such as spherical aberration, astigmatism, etc., thereby improving the clarity and contrast of the image.

[0150] The first lens 1 and the second lens 2, as negative lenses, play a role in diverging light in the optical path, which helps to adjust the incident angle and path of the light. The third lens 3 and the fourth lens 4, as positive lenses, are responsible for refocusing the diverged light to form a clear image. By controlling the ratio of their central thicknesses, the focusing effect of the light can be further optimized, and the imaging quality can be improved.

[0151] By setting the ratio of (T3 + T4) / (T1 + T2) to be between 2 and 2.7, it is possible to achieve the balance of the projection lens module while ensuring the optical performance. This balance helps to reduce light loss, improve light efficiency, and ensure the stability of the entire projection lens module under different environments and working conditions.

[0152] On the premise of meeting the optical performance requirements, by controlling the lens type and thickness ratio, it also helps to achieve the compactness and lightweight design of the projection lens module. This is particularly important for application scenarios such as home projectors where space is limited and portability is required.

[0153] By adopting the configuration where the third lens 3 and the fourth lens 4 are positive lenses and the first lens 1 and the second lens 2 are negative lenses, and controlling the ratio of the sum of their central thicknesses to be between 2 and 2.7, it is possible to effectively correct chromatic aberration, control aberrations, optimize the light focusing effect, and improve the imaging quality. This design is of great significance for achieving a high-quality ultra-short throw projection effect.

[0154] In some examples of the present application, referring to Figure 2 and Figure 5 , the sagittal height of the surface of the twelfth lens 12 close to the aperture 13 at the maximum aperture is S1, and the sagittal height of the surface far from the aperture 13 at the maximum aperture is S2, and the ratio between S2 and S1 is 1.3 < S2 / S1 < 1.8.

[0155] According to the examples provided by the present application, this control condition aims to optimize the light refraction path of the twelfth lens 12 by limiting the sagittal height ratio of its two surfaces, thereby improving the overall performance of the projection lens module. The specific analysis is as follows.

[0156] (1) Optimize the light refraction path: The specific sagittal height ratio design helps to control the light refraction path of the twelfth lens 12. By adjusting the ratio of S2 to S1, the light can transition more smoothly when passing through the twelfth lens 12, reducing light scattering and loss caused by sudden changes in the refraction path, thereby improving the utilization efficiency of light.

[0157] (2) Improve imaging performance: The optimized light refraction path helps to improve the imaging performance of the projection lens. The light can be focused more accurately on the imaging surface, reducing blurring and distortion, making the projected image clearer.

[0158] (3) Enhance the aberration correction effect: The design of the sagittal height ratio has a significant impact on aberration correction. In the examples of this application, by controlling the surface shape of the twelfth lens 12, that is, the sagittal height ratio of the two surfaces, spherical aberration, coma aberration and other aberrations can be corrected more effectively, improving the imaging quality. This is because different sagittal height ratios affect the refraction ability of the lens for incident light at different angles, thereby changing the magnitude and distribution of aberrations.

[0159] (4) Achieve a compact module design: On the premise of meeting the optical performance requirements, by optimizing the shape of the lens (i.e., the sagittal height ratio), the thickness and volume of the lens can be reduced to a certain extent, thereby achieving a more compact design of the projection lens.

[0160] In short, this application realizes multiple technical effects such as optimizing the light refraction path, improving imaging performance, enhancing the aberration correction effect, and achieving a compact design by controlling the sagittal height ratio (S2 / S1) of the twelfth lens 12. These technical effects together improve the overall performance of the projection lens module, providing strong support for its wide application in various application scenarios. At the same time, this design also reflects the fine control and optimization of the optical performance of the projection lens.

[0161] In some examples of this application, the air gap between the diaphragm 13 and the second doublet lens is L1, the air gap between the diaphragm 13 and the first doublet lens is L2, and L1 and L2 satisfy: 100 < TTL / (L1 + L2) < 150.

[0162] According to the examples provided in this application, this ratio reflects the further control of the internal light transmission path of the projection lens. By adjusting the ratio of the air gaps between the diaphragm 13 and the doublet lenses on both sides, the dual purposes of optimizing the optical performance and ensuring a compact lens structure are aimed at.

[0163] Among them, L1 is the distance from the center of the diaphragm 13 to the center of the seventh lens 7, and L2 is the distance from the center of the diaphragm 13 to the center of the sixth lens 6.

[0164] A specific air gap ratio helps optimize the light transmission path of the projection lens module. In this example provided by the present application, by adjusting the relative sizes of L1 and L2, light can propagate along a more reasonable path inside the projection lens module. The optimized light transmission path can ensure that light is focused more accurately on the imaging surface, reducing blurring and distortion. This helps improve the imaging quality of the projection lens, making the projected image clearer and sharper.

[0165] In the example of the present application, by limiting the ratio of TTL / (L1 + L2) between 100 and 150, while ensuring optical performance, the overall size of the lens structure can be effectively controlled. This helps achieve a compact design of the projection lens module, meeting the application requirements of miniaturization and lightweight.

[0166] The ratio of the air gap also affects the refractive ability of the lens for light of different wavelengths. In the example of the present application, by adjusting the air gap ratio, chromatic aberration can be corrected more effectively, making the focus of the projected image more accurate for different colors and the color reproduction higher.

[0167] In some examples of the present application, refer to Figure 3 , the optical power of the third lens 3 is positive. The tangent of the lens at the maximum aperture on the surface of the third lens 3 close to the diaphragm 13 makes an angle A1 with the optical axis, and the tangent of the lens at the maximum aperture on the surface of the third lens 3 far from the diaphragm 13 makes an angle A2 with the optical axis. A1 and A2 satisfy the following relationships: 15° < A2 - A1 < 35° and 1.35 < A2 / A1 < 1.55.

[0168] Regarding the relationship of the angle difference: 15° < A2 - A1 < 35°. This relationship of the angle difference ensures that the third lens 3 has an appropriate angle change during the light refraction process. The appropriate angle change helps optimize the imaging quality. If the angle change is too small, light cannot be refracted sufficiently, resulting in blurred imaging or increased aberration. If the angle change is too large, unnecessary aberration may be introduced, affecting the imaging quality.

[0169] Regarding the relationship of the angle ratio: 1.35 < A2 / A1 < 1.55. This relationship of the angle ratio defines the relative sizes between the tilting angles of the two surfaces of the third lens 3. By controlling the ratio of A2 to A1, the refraction path of light can be controlled, improving the imaging performance of the projection lens. If the ratio is too small or too large, it may lead to an unreasonable refraction path of light, thereby affecting the imaging quality.

[0170] The example provided by the present application can optimize the refraction path of light, making light focus more accurately on the imaging surface, reducing blurring and distortion, thereby improving the imaging quality.

[0171] In some examples of the present application, refer to Figure 4 , the second lens 2 has a negative optical power. The angle between the tangent line of the lens surface of the second lens 2 near the diaphragm 13 at the maximum aperture and the optical axis is A3, and the angle between the tangent line of the lens surface of the second lens 2 far from the diaphragm 13 at the maximum aperture and the optical axis is A4. The relationship between A3 and A4 satisfies: 30° < A4 - A3 < 45°.

[0172] In the examples provided by the present application, the angular difference relationship between the two surfaces of the second lens 2 is given, that is, 30° < A4 - A3 < 45°. This angular difference ensures an appropriate angular change of the second lens 2 during the light refraction process. An appropriate angular change is crucial for optimizing the imaging quality of the projection lens module. If the angular change is too small, the light may not be refracted sufficiently, resulting in ineffective focusing of the light and affecting the imaging quality. On the contrary, if the angular change is too large, unnecessary aberrations will be introduced, which will also damage the imaging effect. In short, the range of 30° to 45° is a carefully designed range aimed at balancing the light refraction effect and aberration control.

[0173] In the examples of the present application, by controlling the tilt angles of the two surfaces of the second lens 2 (i.e., A3 and A4), the refraction path of the light can be adjusted to make the light focus more accurately on the imaging surface. This helps to improve the clarity of the projected image, thereby significantly enhancing the imaging quality.

[0174] During the light propagation process, due to the refraction and reflection of the lens, the light may deviate. By controlling the tilt angles of the two surfaces of the second lens 2 and their difference, these deviations can be effectively corrected to ensure that the light propagates along the expected path, thereby improving the accuracy of the projected image.

[0175] In addition, on the premise of ensuring the optical performance, by controlling the tilt angle of the surface of the second lens 2, the structural layout of the lens can be optimized to a certain extent. This also helps to achieve the miniaturized design of the projection lens.

[0176] In some examples of the present application, refer to Figure 2 and Figure 5 , the projection lens module further includes a galvanometer 14, a prism 15, a glass plate 17, and a display unit 18, which are sequentially arranged along the optical axis on the side of the twelfth lens 12 away from the diaphragm 13.

[0177] In some examples of the present application, refer to Figure 5 , the projection lens further includes a reflection element 16, the reflection element 16 is located on the side of the first lens 1 away from the diaphragm 13, and the reflection element 16 is used to reflect the light for projection imaging to the imaging surface. Refer toFigure 1 。

[0178] In some examples of the present application, the ratio of the total optical length TTL of the projection lens module to the maximum aperture D1 of the lens in the projection lens module satisfies: 4 < TTL / D1 < 4.7.

[0179] In the above examples provided by the present application, the projection lens module not only includes two lens groups and the diaphragm 13, but also introduces the galvanometer 14, the prism 15, the reflecting element 16, the glass plate 17 and the display unit 18, and also specifies the ratio range (4 < TTL / D1 < 4.7) between the total optical length TTL of the projection lens module and the maximum aperture D1 of the lens. The following is a detailed analysis of this design.

[0180] Among them, whether the galvanometer 14 is provided depends on specific application requirements.

[0181] Among them, the prism 15 can be designed as a total internal reflection prism (TIR prism).

[0182] The prism 15 is used to further adjust the direction of light. By reasonably designing the shape and angle of the prism, precise control of the light path can be achieved to meet specific projection requirements.

[0183] Among them, the reflecting element 16 is an aspherical reflecting bowl. It can precisely control the reflection path of light, effectively correct aberrations, thereby improving the imaging quality. The design of the aspherical reflecting bowl enables more light to be effectively reflected onto the imaging surface, improving the utilization rate of light, and further enhancing the brightness and contrast of the projection image. In addition, the design of the aspherical reflecting bowl enables the projection lens module to better adapt to the wide-angle projection requirements and expand the coverage range of the projection image.

[0184] Among them, the display unit 18 is a component of the projection lens module, responsible for generating and providing the light for projection imaging to the projection lens. The display unit 18 is, for example, a high-resolution display device, such as an LCD, DLP or LCOS, etc., which can generate high-quality image signals.

[0185] Among them, the glass plate 17 is placed between the display unit 18 and the prism 15, and is used to ensure that the light emitted from the display unit 18 can efficiently pass through the subsequent prism and lens groups, and finally form a high-quality projection image. The glass plate 17 reduces the loss and interference of light during the transmission process through its characteristics such as high light transmittance and low reflectivity, which is conducive to improving the brightness and contrast of the projection image.

[0186] The ratio of TTL to D1 is directly related to the overall size and optical efficiency of the projection lens module. If the ratio is too small, it means that the overall projection lens module is too compact, resulting in insufficient spacing between optical elements, which in turn affects the light transmission and imaging quality. If the ratio is too large, the volume of the projection lens module may be too large, which is not conducive to miniaturization.

[0187] That is to say, by limiting the ratio of TTL / D1 between 4 and 4.7, the overall size of the projection lens module can be effectively controlled while ensuring optical performance.

[0188] Sufficient TTL can ensure that light has enough propagation distance inside the projection lens module, so as to make more full use of optical elements for refraction and correction, improving imaging quality. At the same time, reasonable D1 can ensure that the lens has sufficient effective light transmission aperture, reducing light loss and improving optical efficiency.

[0189] The combined effect of the compact structure and optimized optical performance enables the optical design of the projection lens module provided in this application to achieve high-quality imaging effects. This includes clear images, accurate color reproduction, low aberration, etc., meeting the user's requirements for high-quality projection images.

[0190] In some examples of this application, the effective focal lengths of the lenses in the projection lens module are as follows: the effective focal length of the first lens 1 is F1, -42 mm ≤ F1 ≤ -34 mm; the effective focal length of the second lens 2 is F2, -56 mm ≤ F2 ≤ -49 mm; the effective focal length of the third lens 3 is F3, 120 mm ≤ F3 ≤ 150 mm; the effective focal length of the fourth lens 4 is F4, 50 mm ≤ F4 ≤ 72 mm; the effective focal length of the first doublet is F', 40 mm ≤ F' ≤ 52 mm; the effective focal length of the second doublet is F", -42 mm ≤ F" ≤ -33 mm; the effective focal length of the ninth lens 9 is F9, 20 mm ≤ F9 ≤ 27 mm; the effective focal length of the third doublet is F''', 50 mm ≤ F''' ≤ 80 mm; the effective focal length of the twelfth lens 12 is F12, 50 mm ≤ F12 ≤ 65 mm.

[0191] In the examples provided in this application, by controlling the effective focal length ranges of each independent lens and each doublet, the refraction and focusing effects of the entire projection lens on light can be optimized, reducing aberration and distortion, and improving the clarity and contrast of imaging. In addition, the reasonable design of the focal length range helps to enhance the light collection ability of the projection lens, correct aberration and improve imaging quality, thereby improving the optical performance of the entire projection lens module.

[0192] In some examples of the present application, the first lens 1 and the fourth lens 4 are plastic aspherical lens elements, the ninth lens 9 is a glass aspherical lens element, the remaining lenses are all glass spherical lenses, and the reflecting element 16 is an aspherical reflecting bowl.

[0193] In an example of the present application, the first lens 1 and the fourth lens 4 are plastic aspherical lenses. The plastic material has a lighter weight and good plasticity, is easy to be processed into an aspherical shape, can effectively correct aberration, and improve the imaging quality. The plastic aspherical lens helps to expand the field of view angle of the projection lens.

[0194] The ninth lens 9 is a glass aspherical lens. The glass aspherical lens combines the high optical performance of glass and the aberration correction ability of an aspherical surface. By using the glass aspherical lens, the refraction path of light can be further optimized, and the imaging quality can be improved.

[0195] The second lens 2, the third lens 3, the fifth lens 5 to the eighth lens 8, and the eleventh lens 11 to the twelfth lens 12 are all glass spherical lenses. The glass material has a high refractive index, low dispersion, and good optical stability, and is suitable for manufacturing spherical lenses. The glass spherical lens can accurately refract light, ensuring the clarity and accuracy of imaging.

[0196] In an example of the present application, by selecting the materials and surface types of each optical lens, it is possible to ensure that the projection lens module has excellent optical performance, reduce aberration and distortion, and improve the clarity and color reproducibility of imaging. Among them, the glass material has good mechanical properties and thermal stability, which can ensure the stable optical performance of the projection lens module during long-term use. The application of the plastic material can reduce the manufacturing cost of the projection lens module while maintaining good optical performance. By reasonably matching the plastic and glass materials, the cost can be reduced on the premise of ensuring the imaging quality.

[0197] The projection lens provided by the present application, in addition to including the aforementioned first lens 1 to the twelfth lens 12, further includes a reflecting element 16, which is designed as an aspherical reflecting bowl. That is to say, the projection lens of the present application includes 13 lenses, among which there are four aspherical lenses: the first lens 1, the fourth lens 4, the ninth lens 9, and the reflecting element 16.

[0198] In some examples of the present application, refer to Figure 2 and Figure 5, the focal length of the projection lens module is 1.444 mm, the projection ratio TR is 0.23, the relative aperture is 1 / 1.71, the Offset is 140%, the pixel size is 5.4 μm, the working wavelength range is 455 nm to 630 nm, the field of view angle is 74° to 78°, and the image plane size is 11.5 mm to 11.9 mm.

[0199] For the projection lens module provided by this application, its focal length is only 1.444 mm. This short focal length helps to achieve a compact design of the projection lens module, and at the same time can project a relatively large image at a relatively short distance, which is suitable for application scenarios with high space requirements.

[0200] For the projection lens module provided by this application, its projection ratio is 0.23. This projection lens module has excellent short-focus projection ability and can project a large image within a limited space, which is very beneficial for places with limited space such as small meeting rooms and home theaters. Users can obtain a clear large-image projection effect at a relatively close position.

[0201] For the projection lens module provided by this application, its relative aperture is 1 / 1.71, which indicates that this projection lens module can collect more light and improve the brightness and contrast of the projection image. The Offset value of 140% indicates that there is a large offset between the optical axis of the projection lens module and the center of the projection image. This design can be used for specific projection requirements, such as achieving special projection angles or avoiding the projection light being blocked.

[0202] The pixel size of 5.4 μm helps to present more delicate details and clearer images in the projection image, meeting the user's requirements for high-quality projection images. The working wavelength range of 455 nm to 630 nm covers the blue to red parts of the visible light, can present a rich variety of colors, and can ensure that the projection image has bright and true color performance, meeting the user's requirements for color quality. The field of view angle of 74° to 78° makes this projection lens module suitable for application scenarios that require large image coverage. The image plane size range of 11.5 mm to 11.9 mm can meet the usage requirements of a certain size of projection chips, and at the same time helps to control the overall size and cost of the projection system.

[0203] According to another embodiment of this application, a projection device is provided, and the projection device includes a housing and the projection lens module as described above.

[0204] The projection device provided by the embodiment of this application is, for example, a household micro-projection device. More specifically, the projection device can be a desktop projection device.

[0205] For the specific implementation of the projection device according to the embodiments of the present application, reference may be made to the respective embodiments of the above projection lens module. Therefore, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, and will not be elaborated herein one by one.

[0206] The projection lens module of the present application will be described below through Embodiment 1 to Embodiment 5 respectively.

[0207] Embodiment 1

[0208] Referring to Figure 5 , the projection lens module provided in Embodiment 1 includes a projection lens, a glass plate 17, and a display unit 18 arranged along the same optical axis. The display unit 18 is configured to provide light for projection imaging to the projection lens, and the projection lens is configured to perform projection imaging on the light emitted by the display unit 18. The projection lens includes a first lens group, a second lens group, and a diaphragm 13 arranged along the same optical axis.

[0209] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a first doublet lens arranged in sequence along the optical axis. Among them, the first doublet lens includes a fifth lens 5 and a sixth lens 6. In the first lens group: the optical powers of the first lens 1 and the second lens 2 are negative, the optical powers of the third lens 3 and the fourth lens 4 are positive, and the optical power of the first doublet lens is positive.

[0210] The second lens group includes a second doublet lens, a ninth lens 9, a third doublet lens, and a twelfth lens 12 arranged in sequence along the optical axis. Among them, the second doublet lens includes a seventh lens 7 and an eighth lens 8, and the third doublet lens includes a tenth lens 10 and an eleventh lens 11. In the second lens group: the optical power of the second doublet lens is negative, the optical power of the ninth lens 9 is positive, the optical power of the third doublet lens is positive, and the optical power of the twelfth lens 12 is positive.

[0211] The diaphragm 13 is located between the first doublet lens and the second doublet lens.

[0212] The projection lens further includes a prism 15, which is disposed between the second lens group and the display unit 18.

[0213] The first lens 1 is a plastic aspherical lens, the second lens 2 and the third lens 3 are glass spherical lenses, the fourth lens 4 is a plastic aspherical lens, the first doublet lens and the second doublet lens are both glass doublet lenses, the ninth lens 9 is a glass aspherical lens, the third doublet lens is a doublet glass lens, the twelfth lens 12 is a glass spherical lens, the glass plate 17 is a glass plate, and the prism 15 is a glass prism.

[0214] See Figure 5 , and the projection lens further includes a reflection element 16, which is located on a side of the first lens group away from the aperture 13 and is configured to reflect the light rays for projection imaging to the imaging surface.

[0215] See Figure 5 , Figure 5 Some optical parameters of the projection lens module shown are shown in Table 1 below.

[0216] Table 1

[0217]

[0218]

[0219] The aspherical parameters of the projection lens module provided in Embodiment 1 are shown in Table 2.

[0220] Table 2

[0221]

[0222] Embodiment 2

[0223] See Figure 6 , the projection lens module provided in Embodiment 2 includes a projection lens, a glass plate 17, and a display unit 18 arranged along the same optical axis. The display unit 18 is configured to provide light rays for projection imaging to the projection lens, and the projection lens is configured to perform projection imaging on the light rays emitted by the display unit 18;

[0224] The projection lens includes a first lens group, a second lens group, and an aperture 13 arranged along the same optical axis;

[0225] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a first doublet lens arranged in sequence along the optical axis. Among them, the first doublet lens includes a fifth lens 5 and a sixth lens 6. In the first lens group: the optical powers of the first lens 1 and the second lens 2 are negative, the optical powers of the third lens 3 and the fourth lens 4 are positive, and the optical power of the first doublet lens is positive;

[0226] The second lens group includes a second doublet lens, a ninth lens 9, a third doublet lens, and a twelfth lens 12 that are sequentially arranged along the optical axis; wherein, the second doublet lens includes a seventh lens 7 and an eighth lens 8, and the third doublet lens includes a tenth lens 10 and an eleventh lens 11; in the second lens group: the optical power of the second doublet lens is negative, the optical power of the ninth lens 9 is positive, the optical power of the third doublet lens is positive, and the optical power of the twelfth lens 12 is positive;

[0227] The aperture stop 13 is located between the first doublet lens and the second doublet lens;

[0228] The projection lens further includes a prism 15 disposed between the second lens group and the display unit 18;

[0229] The first lens 1 is a plastic aspherical lens, the second lens 2 and the third lens 3 are glass spherical lenses, the fourth lens 4 is a plastic aspherical lens, the first doublet lens and the second doublet lens are both glass doublet lenses, the ninth lens 9 is a glass aspherical lens, the third doublet lens is a doublet glass lens, the twelfth lens 12 is a glass spherical lens, the glass plate 17 is a glass plate, and the prism 15 is a glass prism.

[0230] The projection lens further includes a reflecting element 16 located on the side of the first lens group away from the aperture stop 13 for reflecting the light rays of the projection image to the imaging surface, Figure 6 The reflecting element 16 is not shown.

[0231] See Figure 6 , Figure 6 For the partial optical parameters of the projection lens module shown, please refer to Table 3 below.

[0232] Table 3

[0233]

[0234]

[0235]

[0236] For the aspherical parameters in the projection lens module provided in Embodiment 2, please refer to Table 4.

[0237] Table 4

[0238]

[0239]

[0240] Embodiment 3

[0241] See also Figure 7 The projection lens module provided in Example 3 includes a projection lens, a glass plate 17 and a display unit 18 arranged along the same optical axis, wherein the display unit 18 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 18 for imaging;

[0242] The projection lens comprises a first lens group, a second lens group and an aperture 13 arranged along the same optical axis;

[0243] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a first double-cemented lens arranged in sequence along the optical axis; wherein the first double-cemented lens includes a fifth lens 5 and a sixth lens 6; in the first lens group: the first lens 1 and the second lens 2 have negative focal powers, the third lens 3 and the fourth lens 4 have positive focal powers, and the first double-cemented lens has positive focal powers;

[0244] The second lens group includes a second double-cemented lens, a ninth lens 9, a third double-cemented lens and a twelfth lens 12 arranged in sequence along the optical axis; wherein the second double-cemented lens includes a seventh lens 7 and an eighth lens 8, and the third double-cemented lens includes a tenth lens 10 and an eleventh lens 11; in the second lens group: the second double-cemented lens has a negative optical power, the ninth lens 9 has a positive optical power, the third double-cemented lens has a positive optical power, and the twelfth lens 12 has a positive optical power;

[0245] The aperture 13 is located between the first double-cemented lens and the second double-cemented lens;

[0246] The projection lens further includes a prism 15 disposed between the second lens group and the display unit 18;

[0247] The first lens 1 is a plastic aspheric lens, the second lens 2 and the third lens 3 are glass spherical lenses, the fourth lens 4 is a plastic aspheric lens, the first double-cemented lens and the second double-cemented lens are both glass double-cemented lenses, the ninth lens 9 is a glass aspheric lens, the third double-cemented lens is a double-cemented glass lens, the twelfth lens 12 is a glass spherical lens, the glass plate 17 is a glass plate, and the prism 15 is a glass prism.

[0248] The projection lens further includes a reflective element 16, which is located on a side of the first lens group away from the aperture 13 and is used to reflect the light of the projection image to the imaging surface. Figure 7 The reflective element 16 is not shown.

[0249] See also Figure 7 ,Figure 7 For the partial optical parameters of the projection lens module shown, please refer to Table 5 below.

[0250] Table 5

[0251]

[0252]

[0253] For the aspherical parameters in the projection lens module provided in Embodiment 3, please refer to Table 6.

[0254] Table 6

[0255]

[0256]

[0257] Embodiment 4

[0258] Refer to Figure 8 , the projection lens module provided in Embodiment 4 includes a projection lens, a glass plate 17, and a display unit 18 arranged along the same optical axis. The display unit 18 is used to provide light for projection imaging to the projection lens, and the projection lens is used to perform projection imaging on the light emitted by the display unit 18;

[0259] The projection lens includes a first lens group, a second lens group, and a diaphragm 13 arranged along the same optical axis;

[0260] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a first doublet lens arranged in sequence along the optical axis; wherein, the first doublet lens includes a fifth lens 5 and a sixth lens 6; in the first lens group: the optical powers of the first lens 1 and the second lens 2 are negative, the optical powers of the third lens 3 and the fourth lens 4 are positive, and the optical power of the first doublet lens is positive;

[0261] The second lens group includes a second doublet lens, a ninth lens 9, a third doublet lens, and a twelfth lens 12 arranged in sequence along the optical axis; wherein, the second doublet lens includes a seventh lens 7 and an eighth lens 8, and the third doublet lens includes a tenth lens 10 and an eleventh lens 11; in the second lens group: the optical power of the second doublet lens is negative, the optical power of the ninth lens 9 is positive, the optical power of the third doublet lens is positive, and the optical power of the twelfth lens 12 is positive;

[0262] The diaphragm 13 is located between the first doublet lens and the second doublet lens;

[0263] The projection lens further includes a prism 15, which is disposed between the second lens group and the display unit 18;

[0264] The first lens 1 is a plastic aspherical lens, the second lens 2 and the third lens 3 are glass spherical lenses, the fourth lens 4 is a plastic aspherical lens, the first doublet lens and the second doublet lens are both glass doublet lenses, the ninth lens 9 is a glass aspherical lens, the third doublet lens is a doublet glass lens, the twelfth lens 12 is a glass spherical lens, the glass plate 17 is a glass plate, and the prism 15 is a glass prism.

[0265] The projection lens further includes a reflection element 16, which is located on the side of the first lens group away from the aperture stop 13 and is used to reflect the light rays for projection imaging to the imaging surface. Figure 8 The reflection element 16 is not shown.

[0266] See Figure 8 , Figure 8 For the partial optical parameters of the projection lens module shown, please refer to Table 7 below.

[0267] Table 7

[0268]

[0269]

[0270]

[0271] For the aspherical parameters in the projection lens module provided in Embodiment 4, please refer to Table 8.

[0272] Table 8

[0273]

[0274] Embodiment 5

[0275] See Figure 9 , the projection lens module provided in Embodiment 5 includes a projection lens, a glass plate 17, and a display unit 18 that are arranged along the same optical axis. The display unit 18 is used to provide the light rays for projection imaging to the projection lens, and the projection lens is used to perform projection imaging on the light rays emitted by the display unit 18;

[0276] The projection lens includes a first lens group, a second lens group, and an aperture stop 13 that are arranged along the same optical axis;

[0277] The first lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a first doublet lens arranged in sequence along the optical axis; wherein, the first doublet lens includes a fifth lens 5 and a sixth lens 6; in the first lens group: the optical powers of the first lens 1 and the second lens 2 are negative, the optical powers of the third lens 3 and the fourth lens 4 are positive, and the optical power of the first doublet lens is positive;

[0278] The second lens group includes a second doublet lens, a ninth lens 9, a third doublet lens, and a twelfth lens 12 arranged in sequence along the optical axis; wherein, the second doublet lens includes a seventh lens 7 and an eighth lens 8, and the third doublet lens includes a tenth lens 10 and an eleventh lens 11; in the second lens group: the optical power of the second doublet lens is negative, the optical power of the ninth lens 9 is positive, the optical power of the third doublet lens is positive, and the optical power of the twelfth lens 12 is positive;

[0279] The aperture stop 13 is located between the first doublet lens and the second doublet lens;

[0280] The projection lens further includes a prism 15, which is arranged between the second lens group and the display unit 18;

[0281] The first lens 1 is a plastic aspherical lens, the second lens 2 and the third lens 3 are glass spherical lenses, the fourth lens 4 is a plastic aspherical lens, the first doublet lens and the second doublet lens are both glass doublet lenses, the ninth lens 9 is a glass aspherical lens, the third doublet lens is a doublet glass lens, the twelfth lens 12 is a glass spherical lens, the glass plate 17 is a glass plate, and the prism 15 is a glass prism.

[0282] The projection lens further includes a reflecting element 16, which is located on the side of the first lens group away from the aperture stop 13 and is used to reflect the light rays of the projection imaging to the imaging surface, Figure 9 The reflecting element 16 is not shown.

[0283] See Figure 9 , Figure 9 For the partial optical parameters of the projection lens module shown, please refer to Table 9 below.

[0284] Table 9

[0285]

[0286]

[0287]

[0288] For the aspherical parameters in the projection lens module provided in Embodiment 5, please refer to Table 10.

[0289] Table 10

[0290]

[0291] For the projection lens modules provided in the above Embodiments 1 to 5, the optical performance is as follows:

[0292] Refer to Figure 10 , Figure 10 which is the distortion diagram of the projection lens module, and the absolute value of distortion is less than 7%.

[0293] The absolute value of distortion being less than 7% indicates that the shape distortion generated during the imaging process of the projection lens module is relatively small. In this way, when projecting an image, it can maintain its original shape and proportion, making the picture seen by the audience highly similar to the actual object. A projection lens module with an absolute distortion value less than 7% can provide a clear and natural picture, enhancing the visual experience of the audience.

[0294] Refer to Figure 11 , Figure 11 which is the MTF diagram of the projection lens module, and MTF > 0.5 at 93 lp / mm.

[0295] 93 lp / mm represents a relatively high spatial frequency. MTF being greater than 0.5 at this spatial frequency indicates that the projection lens module can better transfer the contrast information of high spatial frequencies. This means that it can clearly present the details in the picture. An MTF value greater than 0.5 indicates that the projection lens module can still maintain a certain contrast at high spatial frequencies and can provide a clear and sharp picture.

[0296] In summary, a projection lens module with an absolute distortion value less than 7% and MTF > 0.5 at 93 lp / mm has excellent imaging performance, can provide a projection picture with accurate shape, rich details, and good contrast, and is suitable for various application scenarios with high requirements for projection quality.

[0297] What was mainly described in the above embodiments is 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, it will not be elaborated here.

[0298] Although some specific embodiments of the present application have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A projection lens module, characterized in that, The projection lens module includes 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 first doublet lens arranged in sequence along the optical axis; The second lens group, including a second doublet lens, a ninth lens (9), a third doublet lens, and a twelfth lens (12) arranged in sequence along the optical axis; A diaphragm (13), located between the first doublet lens and the second doublet lens; Wherein, the total central thickness T' of all the doublet lenses included in the projection lens satisfies the following relationship with the optical total length TTL of the projection lens module: 7% ≤ T' / TTL ≤ 11%.

2. The projection lens module according to claim 1, wherein In the first lens group: the first lens (1) and the second lens (2) have negative optical powers, and the third lens (3), the fourth lens (4), and the first doublet lens all have positive optical powers; In the second lens group: the second doublet lens has a negative optical power, and the ninth lens (9), the third doublet lens, and the twelfth lens (12) all have positive optical powers.

3. The projection lens module according to claim 1 or 2, characterized in that, In the first lens group, the third lens (3) and the fourth lens (4) both have positive optical powers, and the central thickness T3 of the third lens (3), the central thickness T4 of the fourth lens (4), and the optical total length TTL of the projection lens module satisfy the following specific relationships: 4% ≤ T3 / TTL ≤ 4.8%; 3.5% ≤ T4 / TTL ≤ 4.2%.

4. The projection lens module according to claim 1, wherein The first doublet lens includes a fifth lens (5) and a sixth lens (6) that are glued together; The optical powers of the fifth lens (5) and the sixth lens (6) are opposite, the fifth lens (5) has a negative optical power, the sixth lens (6) has a positive optical power, and the refractive index N6 of the sixth lens (6) is higher than the refractive index N5 of the fifth lens (5).

5. The projection lens module according to claim 1, wherein The second doublet lens includes a seventh lens (7) and an eighth lens (8) that are glued together, the optical powers of the seventh lens (7) and the eighth lens (8) are opposite, the seventh lens (7) has a positive optical power, and the eighth lens (8) has a negative optical power; The third doublet lens includes a tenth lens (10) and an eleventh lens (11) that are glued together, the optical powers of the tenth lens (10) and the eleventh lens (11) are opposite, the tenth lens (10) has a negative optical power, and the eleventh lens (11) has a positive optical power; Wherein, the refractive index N7 of the seventh lens (7) is lower than the refractive index N8 of the eighth lens (8), and the refractive index N11 of the eleventh lens (11) is lower than the refractive index N10 of the tenth lens (10).

6. The projection lens module according to claim 5, characterized in that In the second lens group, the seventh lens (7) and the eleventh lens (11) have positive optical powers, and the eighth lens (8) and the tenth lens (10) have negative optical powers, and the following is satisfied: 3.3 < (T7 + T11) / (T8 + T10) < 4, where T7 is the central thickness of the seventh lens (7), T8 is the central thickness of the eighth lens (8), T10 is the central thickness of the tenth lens (10), and T11 is the central thickness of the eleventh lens (11).

7. The projection lens module according to claim 1 or 2, characterized in that, In the first lens group, the central thickness of the first lens (1) is T1, the central thickness of the second lens (2) is T2, the central thickness of the third lens (3) is T3, and the central thickness of the fourth lens (4) is T4. Among them, the ratio between the sum of the central thicknesses of the third lens (3) and the fourth lens (4) (T3 + T4) and the sum of the central thicknesses of the first lens (1) and the second lens (2) (T1 + T2) satisfies: 2 < (T3 + T4) / (T1 + T2) < 2.

7.

8. The projection lens module according to claim 7, wherein The sagittal height of the surface of the twelfth lens (12) close to the aperture stop (13) at the maximum aperture is S1, and the sagittal height of the surface away from the aperture stop (13) at the maximum aperture is S2. The ratio between S2 and S1 is 1.3 < S2 / S1 < 1.

8.

9. The projection lens module according to claim 1, characterized in that, The air gap between the aperture stop (13) and the second doublet is L1, and the air gap between the aperture stop (13) and the first doublet is L2, and the following is satisfied between L1 and L2: 100 < TTL / (L1 + L2) < 150.

10. The projection lens module according to claim 1, wherein The third lens (3) has a positive optical power. The angle between the tangent of the lens surface of the third lens (3) close to the aperture stop (13) at the maximum aperture and the optical axis is A1, and the angle between the tangent of the lens surface of the third lens (3) away from the aperture stop (13) at the maximum aperture and the optical axis is A2. A1 and A2 satisfy the following relationship: 15° < A2 - A1 < 35°; and 1.35 < A2 / A1 < 1.

55.

11. The projection lens module according to claim 1 or 10, characterized in that, The second lens (2) has a negative optical power. The angle between the tangent of the lens surface of the second lens (2) close to the aperture stop (13) at the maximum aperture and the optical axis is A3, and the angle between the tangent of the lens surface of the second lens (2) away from the aperture stop (13) at the maximum aperture and the optical axis is A4. Between A3 and A4, the following is satisfied: 30° < A4 - A3 < 45°.

12. The projection lens module according to claim 1, wherein The projection lens module further includes a galvanometer (14), a prism (15), a glass plate (17), and a display unit (18) that are sequentially arranged along the optical axis on the side of the twelfth lens (12) away from the aperture stop (13); The projection lens further includes a reflecting element (16), which is located on the side of the first lens (1) away from the aperture stop (13) and is used to reflect the light for projection imaging to the imaging surface; The ratio of the total optical length TTL of the projection lens module to the maximum aperture D1 of the lenses in the projection lens module satisfies: 4 < TTL / D1 < 4.

7.

13. The projection lens module according to claim 12, wherein The effective focal lengths of the lenses in the projection lens module are: The effective focal length of the first lens (1) is F1, -42 mm ≤ F1 ≤ -34 mm; The effective focal length of the second lens (2) is F2, -56 mm ≤ F2 ≤ -49 mm; The effective focal length of the third lens (3) is F3, 120 mm ≤ F3 ≤ 150 mm; The effective focal length of the fourth lens (4) is F4, 50 mm ≤ F4 ≤ 72 mm; The effective focal length of the first doublet lens is F', 40 mm ≤ F' ≤ 52 mm; The effective focal length of the second doublet lens is F", -42 mm ≤ F" ≤ -33 mm; The effective focal length of the ninth lens (9) is F9, 20 mm ≤ F9 ≤ 27 mm; The effective focal length of the third doublet lens is F''', 50 mm ≤ F''' ≤ 80 mm; The effective focal length of the twelfth lens (12) is F12, 50 mm ≤ F12 ≤ 65 mm; The first lens (1) and the fourth lens (4) are plastic aspherical lens elements, the ninth lens (9) is a glass aspherical lens element, and the remaining lenses are all glass spherical lenses; The reflection element (16) is an aspherical reflecting bowl.

14. The projection lens module according to claim 13, characterized in that, The projection lens module has a focal length of 1.444 mm, a projection ratio TR of 0.23, a relative aperture of 1 / 1.71, an Offset of 140%, a pixel size of 5.4 μm, an operating wavelength band of 455 nm to 630 nm, a field of view angle of 74° to 78°, and an image plane size of 11.5 mm to 11.9 mm.

15. A projection device, characterized in that, Comprising: A housing; And The projection lens module according to any one of claims 1-14.

Images