Projection lens module and projection equipment

Abstract

The invention discloses a projection lens module and projection equipment, and relates to the technical field of optical imaging lenses, the projection lens module comprises a second lens group, a diaphragm and a first lens group which are sequentially arranged from an object side to an image side along an optical axis, and the first lens group comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged. The second lens group comprises a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens, and the fifth lens, the sixth lens and the seventh lens form a triplet lens; wherein the diaphragm is located between the first lens group and the second lens group; according to the invention, by adopting the front four and back five lenses and ingeniously configuring the two aspheric lenses with negative focal power in the front group, the angle of the chief light is effectively narrowed, the ultra-short focus design is realized, the aperture of the front end is obviously reduced, and the miniaturization of the system is facilitated.

Description

Technical Field

[0001] This invention relates to the field of optical imaging lens technology, specifically to a projection lens module and projection device. Background Technology

[0002] Currently, home smart projectors are developing towards miniaturization, integration, and diversified scenario adaptation. However, the optical architecture of traditional projectors faces fundamental challenges in adapting to these needs, specifically in the following aspects:

[0003] (1) Low space utilization efficiency: In order to achieve a large screen, the projector must be kept at a large distance from the projection wall, which is contrary to the concept of compact layout pursued by modern home space.

[0004] (2) Limited usage scenarios: The projection light path is like a "visual forbidden zone", requiring no obstruction on the projection path, which greatly limits the placement and usage flexibility of the device. For example, it cannot be placed against the wall or in the corner of the furniture.

[0005] The root cause lies in the fact that traditional projection lenses, in order to achieve short-throw characteristics, often rely on increasing the number of lenses or using complex aspherical and freeform surfaces. This not only increases the physical size and manufacturing cost of the optical system, but also faces inherent contradictions in optical parameters: the system's projection ratio and image plane offset are difficult to optimize in a coordinated manner. Overly pursuing short-throw may result in insufficient image offset, forcing the device to be raised at a certain angle to obtain a complete rectangular image, thereby introducing trapezoidal distortion and affecting the user experience. Summary of the Invention

[0006] The purpose of this invention is to provide a projection lens module and a projection device to solve the above-mentioned problems.

[0007] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0008] A projection lens module and projection device include a second lens group, an aperture, and a first lens group arranged sequentially along the optical axis from the object side to the image side. The first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially. The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens, wherein the fifth lens, the sixth lens, and the seventh lens form a cemented triplet lens.

[0009] The aperture stop is located between the first and second lens groups;

[0010] The first lens is an aspherical lens with negative focal length, and its center thickness T1 and the total optical length TTL of the projection lens satisfy the following relationship: 0.015≤T1 / TTL≤0.019;

[0011] In the projection lens, the second lens is an aspherical lens with negative optical power, and the center thickness T2 and the total optical length TTL of the projection lens satisfy the following condition: 0.015≤T2 / TTL≤0.019.

[0012] The third lens has negative optical power, with a concave object side and a convex image side;

[0013] The fourth lens has positive optical power, with a convex object-side surface and a convex image-side surface;

[0014] The overall optical power of the three-layer cemented lens is negative;

[0015] The eighth lens has positive optical power, and is convex on both the object plane and image plane sides.

[0016] The ninth lens has positive optical power, a convex surface on the object side, and a flat surface on the image side;

[0017] The aperture is located between the fourth lens and the cemented triplet lens;

[0018] The effective focal length EFFL of the projection lens module is: 10.2mm≤EFFL≤10.8mm.

[0019] As a preferred embodiment of the present invention, both the first lens and the second lens are plastic aspherical lenses.

[0020] As a preferred embodiment of the present invention, the projection lens module satisfies the condition: 0.018≤BFL / TTL≤0.022;

[0021] Wherein, TTL is the total optical length of the projection lens module; BFL is the optical back focal length of the projection lens module.

[0022] In a preferred embodiment of the present invention, in the three-layer cemented lens: the fifth lens, the sixth lens and the seventh lens are all negative optical power, and the refractive indices of the fifth lens and the seventh lens are both lower than the refractive index of the sixth lens;

[0023] The three-ply cemented lens satisfies the following condition:

[0024] 1.5mm≤T5≤3mm;

[0025] 6.5mm≤T6≤8.5mm;

[0026] 1.5mm≤T7≤3mm;

[0027] Wherein, T5 is the center thickness of the fifth lens, T6 is the center thickness of the fifth lens, and T7 is the center thickness of the fifth lens.

[0028] As a preferred embodiment of the present invention, the air gap between the aperture stop and the fourth lens is L1, and the air gap between the aperture stop and the fifth lens is L2, satisfying the condition: 25mm≤L1, 8mm≤L2.

[0029] As a preferred embodiment of the present invention, the following condition is satisfied in the triple-cemented lens:

[0030] |R11|+|R12|≥30;

[0031] Where R11 is the curvature of the object side surface in the sixth lens, and R12 is the curvature of the image side surface in the sixth lens.

[0032] As a preferred embodiment of the present invention, the effective focal length of all said lenses satisfies the following condition:

[0033] The effective focal length of the first lens is F1, -35mm ≤ F1' ≤ -20mm

[0034] The effective focal length of the second lens is F2, -45mm ≤ F2' ≤ -25mm

[0035] The effective focal length of the third lens is F3, 100mm≤F3'≤200mm

[0036] The effective focal length of the fourth lens is F4, 20mm ≤ F4' ≤ 70mm.

[0037] The effective focal length of the cemented triplex lens is F0, -200mm≤F0'≤-50mm

[0038] The effective focal length of the eighth lens is F8, 20mm≤F8'≤50mm

[0039] The effective focal length of the ninth lens is F9, 30mm≤F9'≤100mm.

[0040] As a preferred embodiment of the present invention, the maximum lens aperture of the projection lens module satisfies the following condition:

[0041] D≤35mm, where D is the maximum lens diameter of the entire projection lens module.

[0042] In a preferred embodiment of the present invention, the center thickness of the ninth lens satisfies the following condition:

[0043] T9≥2mm, where T9 is the center thickness of the ninth lens.

[0044] In a preferred embodiment of the present invention, the maximum center thickness of the lens in the projection lens module satisfies the following condition:

[0045] T≤10mm, where T is the maximum center thickness of the lens in the projection lens module.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] 1. This invention employs a “four-lens-in-the-front, five-lens-in-the-back” configuration and cleverly arranges two negative-power aspherical lenses in the front group, effectively narrowing the main ray angle and achieving an ultra-short focal length design. At the same time, it significantly reduces the front port diameter, which is beneficial for system miniaturization.

[0048] 2. By setting a specific negative optical power lens sequence in the first lens group and coordinating it with the positive optical power of the second lens group, the present invention achieves a large image plane offset, enabling the projection device to be installed close to the wall and project a rectangular image in the correct position.

[0049] 3. By setting a negative optical power triplet lens behind the aperture of the second lens group and preferably using a combination of high dispersion and low dispersion glass, the present invention greatly corrects the secondary spectrum and magnification chromatic aberration of the system, and achieves excellent apochromatic effect under the premise of a limited number of lenses.

[0050] 4. In this invention, the ninth lens adopts a plano-convex shape with a flat image side, which greatly facilitates the bonding and installation with the subsequent DMD chip beam combining prism or protective window, further compresses the overall size of the device, and reduces the sensitivity of system assembly. Attached Figure Description

[0051] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0052] Figure 1 This invention provides a schematic diagram of the lens optical path of a projection lens module and a projection device.

[0053] Figure 2 This invention provides a field curvature and distortion diagram of a projection lens module and a projection device.

[0054] Figure 3 This invention provides a relative illumination diagram of a projection lens module and a projection device.

[0055] Figure 4 This invention provides a lateral chromatic aberration diagram of a projection lens module and a projection device.

[0056] Figure 5 This invention provides an axial aberration diagram of a projection lens module and a projection device.

[0057] Figure 6 The present invention provides a projection lens module and an MTF diagram of the projection lens module of a projection device.

[0058] The labels in the diagram represent the following:

[0059] 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. Glass plate; 11. Prism; 12. Protective sheet; 13. Display unit; 14. Aperture. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Example 1

[0062] like Figures 1-6 As shown, the present invention provides a projection lens module and projection device, comprising a second lens group, an aperture stop, and a first lens group arranged sequentially along the optical axis from the object side to the image side. The first lens group includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 arranged sequentially. The second lens group includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, and a ninth lens 9, wherein the fifth lens 5, the sixth lens 6, and the seventh lens 7 form a cemented triplet lens. The device also includes a glass plate 10, a prism 11, a protective sheet 12, and a display unit 13 arranged sequentially along the optical axis on the side of the ninth lens 9 away from the aperture stop 14.

[0063] In the projection lens, the aperture 14 is located between the first lens group and the second lens group;

[0064] The first lens 1 is an aspherical lens with negative focal length, and its center thickness T1 and the total optical length TTL of the projection lens satisfy the following condition: 0.015≤T1 / TTL≤0.019;

[0065] In the projection lens, the second lens 2 is an aspherical lens with negative optical power, and the central thickness T2 and the total optical length TTL of the projection lens satisfy the following condition: 0.015≤T2 / TTL≤0.019.

[0066] Furthermore, both the first lens 1 and the second lens 2 are plastic aspherical lenses.

[0067] The projection lens satisfies the condition: 0.018≤BFL / TTL≤0.022;

[0068] Where TTL is the total optical length of the projection lens; BFL is the optical back focal length of the projection lens.

[0069] The projection lens is located in the light-emitting path of the display unit 13. The projection lens is responsible for receiving the light emitted from the display unit 13 (this light is dedicated to projection display) and modulating and focusing it. After this series of optical processes, the light is projected onto the imaging surface to form a clear projected image.

[0070] Specifically, the first lens 1 is a negative power aspherical lens. A negative lens allows incident light rays from a large field of view to exit at a gentler angle, reducing the angular pressure on subsequent lens groups. By ensuring that its center thickness T1 and total optical length TTL satisfy 0.015 ≤ T1 / TTL ≤ 0.019, this ratio affects the lens's power distribution and light refraction. Optimizing this ratio can effectively correct specific aberrations such as spherical aberration and astigmatism while shortening the overall length. It also ensures sufficient mechanical strength and processing stability while avoiding unnecessary material absorption and weight increase due to excessive thickness, achieving a balance between lightweight and performance. If T1 / TTL is below the lower limit, the lens is prone to deformation and the thinner center edge is easily chipped; if it is above the upper limit, it unnecessarily increases the system length and cost. Furthermore, the first lens 1 has a large outer diameter area, and using plastic material can effectively reduce costs.

[0071] The second lens 2 is a negative optical power aspherical lens, with both its object-side and image-side surfaces designed aspherically. The first lens 1 and the second lens 2 together form a "double aspherical negative lens group." These two aspherical surfaces work together to accurately correct higher-order distortions and field curvature introduced by ultra-wide field of view. Their central thickness T2 and TTL satisfy 0.015 ≤ T2 / TTL ≤ 0.019. This constraint ensures a reasonable distribution of optical power between the second lens 2 and the first lens 1, avoiding excessive bending of a single lens and effectively controlling spherical and coma aberrations. Furthermore, the second lens 2 is made of plastic, reducing costs. Ordinary spherical lenses generate numerous complex and difficult-to-correct aberrations when dealing with ultra-wide-angle beams. By combining two plastic aspherical surfaces and controlling the ratio of thickness to total optical length within a certain range, both optical performance and processing performance are satisfied, improving yield.

[0072] In the projection lens module provided in this application, the aperture 14, as a key optical element, is positioned between the first lens group and the second lens group. This allows the first lens group to undertake the main function of light angle convergence. Before light enters the aperture 14 from the image plane, its maximum incident angle is effectively controlled, thereby reducing the angular sensitivity of the incident light from the subsequent second lens group. This structure facilitates the rational distribution of aberration correction burden before and after the aperture 14: the first lens group can focus on correcting aberrations such as field curvature and distortion, while the second lens group can more effectively correct spherical aberration and coma, and achieve good image-side telecentricity. As a result, a more uniform illumination distribution and resolution are obtained across the entire image plane, effectively overcoming the problem of edge image quality degradation. Because the light is effectively constrained at the aperture 14, the aperture of the first lens in the second lens group located after the aperture 14 is also controlled. This not only reduces the cost of lens materials but also makes the lens structure more compact, which is beneficial for the miniaturization design of projector devices.

[0073] The third lens 3 has negative optical power, with a concave object side and a convex image side. It is a meniscus lens with negative optical power, but its optical power is very small. Its main function is to correct field curvature using the thick meniscus lens, rather than to provide optical power. In addition, the radius variation of the meniscus lens can also facilitate aberration correction.

[0074] The fourth lens 4 has positive optical power, with a convex object side and a convex image side. The fourth lens 4 is a converging lens with positive optical power, which works in conjunction with the third lens 3, which has negative optical power, to correct field curvature and converge the beam to enter the aperture at a gentle angle.

[0075] The overall optical power of the cemented triplet lens is negative; the cemented triplet lens composed of the fifth lens 5, the sixth lens 6, and the seventh lens 7 mainly has a negative overall optical power. By selecting a combination of optical materials with different dispersion characteristics, this cemented triplet lens can efficiently correct the second-order spectral and magnification chromatic aberration of the system, which is the core of achieving high-performance apochromatic design.

[0076] Furthermore, in the cemented triplet lens: the fifth lens 5, the sixth lens 6, and the seventh lens 7 all have negative optical power, and the refractive indices of the fifth lens 5 and the seventh lens 7 are both lower than the refractive index of the sixth lens 6.

[0077] Among them, the triplex lens satisfies the following condition:

[0078] 1.5mm≤T5≤3mm;

[0079] 6.5mm≤T6≤8.5mm;

[0080] 1.5mm≤T7≤3mm;

[0081] Wherein, T5 is the center thickness of the fifth lens 5, T6 is the center thickness of the fifth lens 5, and T7 is the center thickness of the fifth lens 5.

[0082] In a cemented triplet lens, the following condition must be satisfied:

[0083] |R11|+|R12|≥30;

[0084] Where R11 is the curvature of the object side surface in the sixth lens 6, and R12 is the curvature of the image side surface in the sixth lens 6. Controlling R11|+|R12|≥30, 1.5mm≤T5≤3mm, 6.5mm≤T6≤8.5mm, and 1.5mm≤T7≤3mm ensures optical performance while improving yield. Exceeding these ranges significantly reduces yield. By placing a negative optical power cemented triplet lens after the aperture 14 of the second lens group, and optimizing the combination of high-dispersion and low-dispersion glass, the system's second-order spectral and magnification chromatic aberration are greatly corrected, achieving excellent apochromatic effect with a limited number of lenses. Furthermore, the addition of the cemented triplet lens significantly improves the overall sharpness of the projected image, ensuring accurate representation of every detail. Simultaneously, it greatly enhances color reproduction and saturation, providing users with a more realistic and vivid visual experience.

[0085] The eighth lens 8 has a positive optical power, and is convex on both the object plane and image plane sides.

[0086] The ninth lens 9 has positive optical power, a convex surface on the object side, and a flat surface on the image side;

[0087] The center thickness of the ninth lens 9 satisfies the following condition:

[0088] T9≥2mm, where T9 is the center thickness of the ninth lens 9.

[0089] The eighth lens (8) and the ninth lens (9) form a positive lens group with positive optical power. Their function is to converge light rays onto the image plane and correct aberrations.

[0090] The ninth lens 9 adopts a plano-convex shape with a flat side, which greatly facilitates the bonding and installation with the subsequent DMD chip beam combining prism or protective window, further reducing the overall size of the device and lowering the sensitivity of system assembly.

[0091] The aperture stop is located between the fourth lens 4 and the cemented triplet lens;

[0092] The effective focal length (EFFL) of the lens module is 10.2mm ≤ EFFL ≤ 10.8mm.

[0093] Furthermore, the air gap between the aperture stop and the fourth lens 4 is L1, and the air gap between the aperture stop and the fifth lens 5 is L2, satisfying the conditions: 25mm≤L1, 8mm≤L2.

[0094] To meet the requirements of a 1200mm working distance, a 0.39DMD chip image sensor, and distortion-free imaging, the lens focal length f of this invention was designed and limited to between 10.2mm and 10.8mm after system optimization. This focal length range is a key parameter for achieving the optimal match between imaging field of view, working distance, and image resolution in the aforementioned specific application scenarios.

[0095] The effective focal length of all lenses satisfies the following condition:

[0096] The effective focal length of the first lens 1 is F1, -35mm ≤ F1' ≤ -20mm

[0097] The effective focal length of the second lens 2 is F2, -45mm≤F2'≤-25mm

[0098] The effective focal length of the third lens 3 is F3, 100mm≤F3'≤200mm

[0099] The effective focal length of the fourth lens 4 is F4, 20mm ≤ F4' ≤ 70mm

[0100] The effective focal length of a cemented triplet lens is F0, -200mm ≤ F0' ≤ -50mm.

[0101] The effective focal length of the eighth lens 8 is F8, 20mm ≤ F8' ≤ 50mm

[0102] The effective focal length of the ninth lens 9 is F9, 30mm≤F9'≤100mm.

[0103] The maximum lens aperture of the projection module satisfies the following condition:

[0104] D≤35mm, where D is the maximum lens diameter of the entire projection module.

[0105] The maximum center thickness of the lens in the projection module satisfies the following condition:

[0106] T≤10mm, where T is the maximum center thickness of the lens in the projection module.

[0107] In this application, the projection lens module achieves precise control and focusing of the light propagation path through the specially designed effective focal length range of each lens, thereby significantly improving the imaging quality and the overall performance of the system.

[0108] See Table 1, which shows some optical parameters of the projection lens module provided in this embodiment.

[0109] Table 1: Optical Parameters of Projection Lens Module

[0110]

[0111] Table 2 shows the aspherical parameters of the projection lens module provided in this embodiment.

[0112] Table 2: Aspherical Parameters of Projection Lens Module

[0113]

[0114] See Figure 6 , Figure 6 The MTF plot of the projection lens module shows that the MTF across the entire field of view remains at 111lp > 0.6. This indicates that the projection lens module maintains excellent contrast transmission capability and resolution at high spatial frequencies throughout the entire effective image area, avoiding image blurring caused by insufficient lens resolution.

[0115] See Figure 2 The absolute value of optical distortion across the entire field of view of this lens module is controlled to within 1%. This ensures that the projected image is distortion-free and undistorted, providing a quasi-display foundation for engineering design and professional presentations. At the same time, it greatly reduces the reliance on electronic keystone correction, guarantees image integrity and resolution, and significantly simplifies the calibration process for multi-projection splicing and blending, improving the overall visual comfort and professional reliability of the solution.

[0116] See Figure 3 The relative illumination of the whole image plane of this lens module is greater than 99%. This indicator first and foremost completely eliminates the visual vignetting of the projected image, ensuring high consistency of brightness and color from the center to the edge.

[0117] See Figure 4 The vertical chromatic aberration of this lens module across the entire field of view is less than 1 micrometer. This specification results in a more natural image display after projection, ensuring that the projected image does not exhibit any visible red, green, or blue color cast that would affect the user's viewing experience.

[0118] See Figure 5 The axial aberration of the entire image plane of this lens module is less than 0.017 mm. This specification provides a clear optical parameter basis for the lens's excellent image quality.

[0119] The projection lens module in this invention features an optical design with short focal length, high throw ratio, and large offset. By employing a "four-lens-front, five-lens-rear" configuration and cleverly placing two negative-power aspherical lenses in the front group, the main ray angle is effectively narrowed, achieving an ultra-short focal length design. Simultaneously, the front port diameter is significantly reduced, facilitating system miniaturization. Furthermore, by setting a specific negative-power lens sequence in the first lens group and coordinating it with the positive-power lens in the second lens group, a large image offset is achieved, allowing the projection device to be mounted flush against the wall and project a correctly positioned rectangular image.

[0120] Example 2

[0121] This invention provides a miniature projection device, which includes a housing and a projection lens module as described above. The specific implementation of the miniature projection device in this embodiment is described in Embodiment 1.

[0122] The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A projection lens module and projection device, characterized in that, Along the optical axis from the object side to the image side, there are a second lens group, an aperture stop (14) and a first lens group. The first lens group includes a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4) arranged in sequence. The second lens group includes a fifth lens (5), a sixth lens (6), a seventh lens (7), an eighth lens (8) and a ninth lens (9). The fifth lens (5), the sixth lens (6) and the seventh lens (7) form a cemented triplet lens. Among them, the aperture (14) is located between the first lens group and the second lens group; The first lens (1) is an aspherical lens with negative focal length, and its center thickness T1 and the total optical length TTL of the projection lens satisfy the following condition: 0.015≤T1 / TTL≤0.019; In the projection lens, the second lens (2) is an aspherical lens with negative optical power, and the central thickness T2 and the total optical length TTL of the projection lens satisfy the following condition: 0.015≤T2 / TTL≤0.019; The third lens (3) has negative optical power, with a concave object side and a convex image side; The fourth lens (4) has positive optical power, with a convex object side and a convex image side; The overall optical power of the three-layer cemented lens is negative; The eighth lens (8) has positive optical power, with a convex surface on the object side and a convex surface on the image side; The ninth lens (9) has positive optical power, with a convex surface on the object side and a flat surface on the image side; The aperture stop (14) is located between the fourth lens (4) and the cemented triplet lens; The effective focal length EFFL of the projection lens module is: 10.2mm≤EFFL≤10.8mm.

2. The projection lens module and projection device according to claim 1, characterized in that: Both the first lens (1) and the second lens (2) are plastic aspherical lenses.

3. The projection lens module and projection device according to claim 2, characterized in that: The projection lens module satisfies the condition: 0.018≤BFL / TTL≤0.022; Wherein, TTL is the total optical length of the projection lens module; BFL is the optical back focal length of the projection lens module.

4. The projection lens module and projection device according to claim 1, characterized in that: In the three-layer cemented lens: the fifth lens (5), the sixth lens (6) and the seventh lens (7) are all negative optical power, and the refractive index of the fifth lens (5) and the seventh lens (7) is lower than that of the sixth lens (6); The three-ply cemented lens satisfies the following condition: 1.5mm≤T5≤3mm; 6.5mm≤T6≤8.5mm; 1.5mm≤T7≤3mm; Wherein, T5 is the center thickness of the fifth lens (5), T6 is the center thickness of the fifth lens (5), and T7 is the center thickness of the fifth lens (5).

5. A projection lens module and projection device according to claim 1, characterized in that: The air gap between the aperture stop (14) and the fourth lens (4) is L1, and the air gap between the aperture stop (14) and the fifth lens (5) is L2, satisfying the condition: 25mm≤L1, 8mm≤L2.

6. The projection lens module and projection device according to claim 1, characterized in that: In the aforementioned cemented triplet lens, the following condition is satisfied: |R11|+|R12|≥30; Where R11 is the curvature of the object side of the sixth lens (6), and R12 is the curvature of the image side of the sixth lens (6).

7. A projection lens module and projection device according to claim 1, characterized in that: The effective focal length of all the lenses described satisfies the following condition: The effective focal length of the first lens (1) is F1, -35mm ≤ F1' ≤ -20mm The effective focal length of the second lens (2) is F2, -45mm ≤ F2' ≤ -25mm The effective focal length of the third lens (3) is F3, 100mm≤F3'≤200mm The effective focal length of the fourth lens (4) is F4,20mm≤F4'≤70mm The effective focal length of the cemented triplex lens is F0, -200mm≤F0'≤-50mm The effective focal length of the eighth lens (8) is F8, 20mm ≤ F8' ≤ 50mm. The effective focal length of the ninth lens (9) is F9,30mm≤F9'≤100mm.

8. The projection lens module and projection device according to claim 1, characterized in that: The maximum lens aperture of the projection lens module satisfies the following condition: D≤35mm, where D is the maximum lens diameter of the entire projection lens module.

9. A projection lens module and projection device according to claim 1, characterized in that: The center thickness of the ninth lens (9) satisfies the following condition: T9≥2mm, where T9 is the center thickness of the ninth lens (9).

10. A projection lens module and projection device according to claim 1, characterized in that: In the projection lens module, the maximum center thickness of the lens satisfies the following condition: T≤10mm, where T is the maximum center thickness of the lens in the projection lens module.

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