Projection lens module and projection equipment

Abstract

An embodiment of the present application provides a projection lens module and a projection device; the projection lens module includes a first lens group, an aperture and a second lens group in sequence from the image side to the object side along the optical axis; the first lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence, wherein: the first lens is an aspheric lens with positive optical focal length, and the relationship between its center thickness T1 and the total optical length TTL of the projection lens module satisfies: 2.4%<T1 / TTL<3.1%; the second lens, the third lens and the fourth lens are cemented together to form a triplet lens, and the triplet lens as a whole has negative optical focal length; the second lens group includes a fifth lens to an eleventh lens arranged in sequence, wherein: the fifth lens to the eighth lens have positive optical focal length; the ninth lens to the eleventh lens have negative optical focal length; the aperture is located between the triplet lens and the fifth lens.

Description

Technical Field

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

[0002] Existing home projectors usually adopt desktop projection mode, which has the following two problems:

[0003] (1) Large space occupation: The projector needs to be far away from the projection wall, which takes up a large space;

[0004] (2) Occlusion restriction: There must be no obstructions in the projection light path, which will affect the flexibility of use.

[0005] Traditional projection lenses typically require complex optical designs to achieve short-throw effects, such as increasing the number of lenses or employing specialized curved surfaces. This results in a bulky and costly optical system. Furthermore, existing technologies struggle to balance throw ratio (TR) and offset, impacting image size and installation flexibility.

[0006] Therefore, there is an urgent need for a compact projection lens module that can achieve short focus, small throw ratio, and large offset with a small number of lenses while ensuring optical performance. Summary of the Invention

[0007] The purpose of this application is to provide a new technical solution for a projection lens module and a projection device.

[0008] In a first aspect, an embodiment of the present application provides a projection lens module, wherein the projection lens module includes a first lens group, an aperture stop, and a second lens group in sequence from the image side to the object side along the optical axis;

[0009] The first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged in sequence, wherein:

[0010] The first lens is an aspheric lens with positive refractive power, and the relationship between the center thickness T1 of the first lens and the total optical length TTL of the projection lens module satisfies the following conditions: 2.4%<T1 / TTL<3.1%;

[0011] The second lens, the third lens and the fourth lens are cemented together to form a triplet lens, and the triplet lens has a negative optical power as a whole;

[0012] The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in sequence, wherein:

[0013] The fifth lens to the eighth lens have positive refractive power;

[0014] The ninth lens to the eleventh lens have negative optical power;

[0015] The aperture stop is located between the triplet lens and the fifth lens.

[0016] Optionally, the central thickness T' of the triplet lens satisfies: 5.2% < T' / TTL < 6.1%.

[0017] Optionally, in the triplet lens: the second lens and the fourth lens have positive optical power, the third lens has negative optical power, and the refractive indices of the second lens and the fourth lens are both lower than that of the third lens;

[0018] The triplet lens satisfies: 4.8 < (T2 + T4) / T3 < 6.1, where T2 is the central thickness of the second lens, T3 is the central thickness of the third lens, and T4 is the central thickness of the fourth lens.

[0019] Optionally, 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 relationship: 1.8 < L2 / L1 < 2.4.

[0020] Optionally, the air gap between the fifth lens and the sixth lens is L3, satisfying the relationship: 7 < TTL / (L2 + L3) < 9.4.

[0021] Optionally, the angle between the tangent line at the maximum aperture of the image side of the fifth lens and the optical axis is A5, and the angle between the tangent line at the maximum aperture of the object side of the fifth lens and the optical axis is A6, satisfying the relationship: 5° < A6 - A5 < 25° and 60° < (A5 + A6) / 2 < 75°.

[0022] Optionally, the sagittal height at the maximum aperture of the image side of the sixth lens is S3, and the sagittal height at the maximum aperture of the object side of the sixth lens is S4, satisfying the relationship: 1.4 < S3 / S4 < 2.2. ​​​​​​​Optionally, the sagittal height at the maximum aperture of the image side of the eighth lens is S1, and the sagittal height at the maximum aperture of the object side of the eighth lens is S2, satisfying the relationship: 2.9 < S2 / S1 < 3.8.

[0026] Optionally, the angle between the tangent line at the maximum aperture of the object side of the tenth lens and the optical axis is A1, and the angle between the tangent line at the maximum aperture of the image side of the tenth lens and the optical axis is A2, satisfying the relationships: 14° < A1 - A2 < 26° and 0.6 < A2 / A1 < 0.85.

[0027] Optionally, the projection lens module further includes a prism, a glass plate, and a display unit that are sequentially arranged on the image side of the first lens;

[0028] The projection lens module further includes an aspherical reflecting bowl on the object side of the eleventh lens;

[0029] The total optical length TTL of the projection lens module and the maximum aperture D1 of the lens in the projection lens module satisfy the relationship: 4.5 < TTL / D1 < 5.3.

[0030] Optionally, the effective focal lengths of the lenses in the projection lens module satisfy:

[0031] The effective focal length of the first lens is F1, 9 mm ≤ F1 ≤ 14 mm;

[0032] The effective focal length of the triplet lens is F', -75 mm ≤ F' ≤ -55 mm;

[0033] The effective focal length of the fifth lens is F5, 50 mm ≤ F5 ≤ 70 mm;

[0034] The effective focal length of the sixth lens is F6, 80 mm ≤ F6 ≤ 105 mm;

[0035] The effective focal length of the seventh lens is F7, 39 mm ≤ F7 ≤ 52 mm;

[0036] The effective focal length of the eighth lens is F8, 40 mm ≤ F8 ≤ 53 mm;

[0037] The effective focal length of the ninth lens is F9, -80 mm ≤ F9 ≤ -60 mm;

[0038] The effective focal length of the tenth lens is F10, -75 mm ≤ F10 ≤ -55 mm;

[0039] The effective focal length of the eleventh lens is F11, -20 mm ≤ F11 ≤ -14 mm;

[0040] The first lens is a glass aspheric lens, the eleventh lens is a plastic aspheric lens, and the remaining lenses are all glass spherical lenses.

[0041] In a second aspect, an embodiment of the present application provides a projection device, comprising:

[0042] casing; and

[0043] The projection lens module as described in the second aspect.

[0044] The beneficial effects of this application are:

[0045] The present invention provides a projection lens module with a short-focus (focal length of approximately 1.27 mm), low throw ratio (TR of approximately 0.25), and large offset (offset of approximately 140%) optical design. By designing the first lens group (near the image side) as a combination of a positive-power aspheric lens and a negative-power triplet lens, combined with a "four positive and three negative" power distribution in the second lens group (near the object side), effective optical path control is achieved using only 11 lenses. This specific arrangement allows light to converge in the first lens group before diverging and then being modulated by the second lens group, laying the foundation for the miniaturization of the projection lens module.

[0046] The ratio of the center thickness T1 of the first lens element to the total optical length TTL is controlled at 2.4% to 3.1%. This design not only ensures the machinability of the aspheric lens (avoiding the risk of breakage due to excessive thinness), but also ensures that it has sufficient refractive power to correct aberrations. At the same time, the negative optical power design of the triplet lens effectively compensates for the chromatic aberration produced by the front group.

[0047] The aperture is set between the triplet lens and the fifth lens. This layout allows the light to complete aperture constraint before entering the second lens group. This not only controls stray light but also balances the pupil matching of the front and rear lens groups, helping to improve the illumination uniformity of the edge field of view.

[0048] Furthermore, the second lens group utilizes a "positive-positive-positive-positive-negative-negative-negative" optical power distribution, which cancels out positive and negative aberrations. In particular, the configuration of the three negative lenses in the rear group effectively corrects the field curvature produced by the positive lenses in the front group while maintaining the short-throw characteristics of the projection lens module.

[0049] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0051] Figure 1 This is a schematic diagram of the working state of the projection lens module of the present application when applied to a projection optical machine;

[0052] Figure 2 A schematic diagram of an optical architecture of a projection lens module provided in an embodiment of the present application;

[0053] Figure 3 A schematic diagram of the partial structure of the tenth lens provided in an embodiment of the present application;

[0054] Figure 4 A schematic diagram of the partial structure of the sixth lens provided in an embodiment of the present application;

[0055] Figure 5 A schematic diagram of the partial structure of the fifth lens provided in an embodiment of the present application;

[0056] Figure 6 The structure and optical path diagram of the projection lens module provided in Example 1 of the present application;

[0057] Figure 7 The structure and optical path diagram of the projection lens module provided in Example 2 of the present application;

[0058] Figure 8 The structure and optical path diagram of the projection lens module provided in Example 3 of the present application;

[0059] Figure 9 The structure and optical path diagram of the projection lens module provided in Example 4 of the present application;

[0060] Figure 10 The structure and optical path diagram of the projection lens module provided in Example 5 of the present application;

[0061] Figure 11 A distortion diagram of the projection lens module provided in an embodiment of the present application;

[0062] Figure 12 This is the MTF diagram of the projection lens module provided in an embodiment of the present application.

[0063] Description of reference numerals:

[0064] 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. Aperture stop; 13. Aspheric reflective bowl; 14. Prism; 15. Glass plate; 16. Display unit. DETAILED DESCRIPTION

[0065] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0066] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0067] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0068] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0069] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0070] The projection lens module and projection device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0071] According to one embodiment of the present application, a projection lens module is provided. Figure 1 and Figure 2 The projection lens module includes a first lens group, an aperture 12 and a second lens group in sequence from the image side to the object side along the optical axis; the first lens group includes a first lens 1, a second lens 2, a third lens 3 and a fourth lens 4 arranged in sequence, wherein: the first lens 1 is an aspheric lens with positive focal length, and the relationship between its center thickness T1 and the total optical length TTL of the projection lens module satisfies: 2.4%<T1 / TTL<3.1%; the second lens 2, the third lens 3 and the fourth lens 4 are cemented to form a triplet lens, and the triplet lens as a whole has negative focal power; the second lens group includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10 and an eleventh lens 11 arranged in sequence, wherein: the fifth lens 5 to the eighth lens 8 have positive focal power; the ninth lens 9 to the eleventh lens 11 have negative focal power; the aperture 12 is located between the triplet lens and the fifth lens 5.

[0072] Most mainstream projectors on the market today utilize tabletop projection, which presents two significant practical issues. First, because the projector must be placed at a certain distance to project a sufficiently large image, it often occupies a significant amount of space, limiting the user's freedom in furniture placement and overall interior layout. Second, tabletop projection requires a clear barrier between the projector and the projection wall, as any obstruction would directly affect the integrity and clarity of the projected image, thereby diminishing the user's viewing experience.

[0073] The projection lens module is a core optical component in a projection engine. To overcome the aforementioned issues, the optical design of the projection lens module is crucial. Specifically, throw ratio (TR) and offset are two important parameters in the optical design of a projection lens module. Throw ratio is defined as the ratio of projection distance to projection image width, determining the size of the projected image at a given projection distance. Under the same conditions, a smaller throw ratio means a larger image can be projected at the same projection distance, thus providing better display quality. Offset refers to the vertical offset between the center of the projected image and the center of the projection lens (the core component of the projection lens module) as a percentage of the projected image height. It reflects the degree of offset of the projected image relative to the entire projection engine. Under the same conditions, a larger offset moves the projected image further away from the projector, making it less likely to be obstructed by the projector body, thereby increasing projection flexibility and convenience. However, it is worth noting that smaller throw ratios and larger offsets increase the optical design complexity of the projection lens module, as this requires achieving higher aberration correction capabilities within a limited space.

[0074] The projection lens module provided in the embodiments of the present application, through a carefully designed optical structure, achieves a focal length of only 1.27mm, a throw ratio of only 0.25, and an offset value of 140%. The projection lens in this projection lens module utilizes a combination of 11 lenses, creating an efficient optical path within a limited space, thereby delivering the desired display effect of an ultra-short-throw projection device. The projection lens module provided in the embodiments of the present application is described in detail below.

[0075] See also Figure 2 The projection lens module provided in the embodiments of the present application includes a projection lens, a display unit 16 located on the image side of the projection lens, and an aspherical reflective bowl 13 located on the object side of the projection lens. The projection lens is the core optical component of the entire projection lens module, and its optical design and performance are directly related to the quality of the final projection effect. The projection lens will be first described in detail below.

[0076] The projection lens module provided in the embodiment of the present application includes a projection lens, see Figure 2 The projection lens comprises three main components, sequentially along the optical axis from the image side to the object side: a first lens group, an aperture 12, and a second lens group. This layout ensures that light enters the first lens group from the image side (i.e., the side where the display unit 16 is located), is adjusted by the aperture 12, and then passes through the second lens group to the object side.

[0077] 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. Figure 2 .

[0078] The first lens 1, as the lens closest to the image side (i.e., the display unit 16 side) in the first lens assembly, adopts an aspheric design with positive optical power. This design can effectively correct various aberrations, including but not limited to spherical aberration and coma, thereby significantly improving image quality. Furthermore, the center thickness T1 of the first lens 1 and the total optical length TTL of the entire projection lens module maintain an optimized design ratio, namely 2.4% < T1 / TTL < 3.1%. This design is intended to maximize optical performance and ensure that light is optimally focused and corrected when passing through the first lens 1.

[0079] In the first lens assembly design provided in the embodiments of this application, the first lens group 1 is followed by the second lens group 2, the third lens group 3, and the fourth lens group 4. These three elements are tightly bonded together through a cementing process to form a triplet lens with negative optical power. This negative optical power is designed to effectively compensate for the potential chromatic aberration caused by the positive lens group 1, thereby optimizing overall image quality. Furthermore, the cemented structure reduces the air interface encountered by light during transmission, helping to reduce stray light and further enhance image purity.

[0080] Specifically, the triplet lens in the embodiment of the present application (composed of the second lens 2 to the fourth lens 4 cemented together) adopts a combination of two positive lenses (the second lens 2 and the fourth lens 4) and a negative lens (the third lens 3). For the specific layout, please refer to Figure 2 , and there's a certain refractive index difference between the positive and negative lenses. This design, by offsetting and compensating for the positive and negative focal powers, not only corrects for chromatic aberration and image aberration, but also specifically addresses the potential differences in focusing between different wavelengths of light. Therefore, the addition of the triplet lens in the first lens group significantly improves the overall clarity of the projected image, ensuring that every detail is accurately rendered. It also significantly enhances color reproduction and saturation, providing users with a more realistic and vivid visual experience.

[0081] The second lens group includes, in sequence, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, and an eleventh lens 11. In this optical architecture, the fifth through eighth lenses 5 through 8 are designed with positive optical power, which helps converge light and form a clear image. Meanwhile, the ninth through eleventh lenses 9 through 11 are designed with negative optical power, which helps correct aberrations, particularly field curvature and distortion, further improving image quality.

[0082] Regarding the second lens group, it should be noted that the four positive lenses provide the main optical power, and the three negative lenses can be used to balance field curvature and distortion, forming a symmetrical aberration compensation structure.

[0083] The aperture 12 is located between the first lens group and the second lens group. Specifically, the aperture 12 is located between the triplet lens and the fifth lens 5, which can accurately control the aperture of the incident light beam and optimize pupil matching.

[0084] In addition, the aperture 12 also plays an important role in reducing stray light. Its position is carefully designed to optimize the light path, reduce stray light, and improve the contrast and brightness uniformity of the picture.

[0085] The projection lens module provided in the present embodiment utilizes a carefully designed optical power distribution scheme, achieving an effective combination of positive optical power and subsequent negative optical power in the first lens group. Meanwhile, the second lens group employs a nearly symmetrical distribution of positive and negative optical power. This unique optical structure enables the resulting projection lens module to achieve a throw ratio of 0.25 at extremely short focal lengths (e.g., 1.27mm), meeting the requirements of ultra-short-throw projection technology for projecting large images at close range.

[0086] The projection lens module provided in this embodiment features a first lens 1 independently positioned within its first lens group (also known as the front lens group). This first lens 1 utilizes an aspherical design, effectively correcting spherical aberration and thereby enhancing image sharpness and clarity. Furthermore, a triplet lens is integrated within the first lens group. This structure, through the combination of materials with different refractive indices, effectively compensates for axial chromatic aberration and ensures accurate color reproduction.

[0087] In the second lens group (or rear group), the first four lenses collectively carry the majority of the projection lens module's optical power, providing the necessary optical support for imaging. The last three lenses, designed with negative optical power, primarily counteract field curvature and distortion, ensuring an overall flat projection image with distortion controlled to less than 5%, providing users with a more realistic, distortion-free visual experience. This optical design ensures excellent chromatic aberration balance across the 455-630nm wavelength range, ensuring rich and accurate projection images.

[0088] In the projection lens module provided in the embodiments of the present application, the aperture 12 is located at the transition between the first and second lens groups. This design not only effectively constrains the aperture of the light beam and controls the amount of light entering the subsequent lens groups, thereby optimizing the performance of the projection lens module, but also significantly reduces the generation of stray light. Through this design, the relative illumination of the projection lens module provided in the embodiments of the present application is increased to a level exceeding 65%, while also significantly improving the brightness uniformity of the peripheral field of view, providing users with a brighter and more uniform projection image.

[0089] The projection lens module provided in the embodiments of the present application achieves efficient optical path layout within a compact space, where the total optical length (TTL) of the projection lens module is only 129mm and the maximum lens aperture is limited to 25.6mm, by regulating the center thickness ratio of each lens, for example, the ratio between the center thickness (T1) of the first lens 1 and the total optical length (TTL) of the projection lens module, and by employing a triplet lens design. Notably, the ratio of TTL (total optical length) to D1 (maximum lens aperture) of this projection lens module is controlled within a range of 4.5 to 5.3, significantly outperforming similar designs on the market and demonstrating excellent optical performance and space utilization.

[0090] In addition, in the embodiment of the present application, the center thickness ratio of the first lens 1 is limited (2.4% to 3.1%) to avoid the risk of processing cracking due to excessive thinning, and the negative optical power design of the triplet lens reduces the dependence on high refractive index materials.

[0091] It is worth noting that the projection lens module provided in the embodiment of the present application may include only eleven lenses, which strikes a balance between optical performance and production cost.

[0092] As can be seen, the projection lens module provided in the embodiments of the present application is designed to achieve ultra-short-throw projection and a large offset, thereby addressing the issues of traditional projection equipment, such as large space requirements and susceptibility to obstruction. Through a carefully designed lens combination and arrangement, as well as an optimized aperture position, the projection lens module provided in the embodiments of the present application is able to project a large and clear image from an extremely short distance while minimizing obstruction of the image by the projector body.

[0093] In some examples of the present application, the center thickness T' of the triplet lens satisfies: 5.2%<T' / TTL<6.1%.

[0094] The negative focal power of the triplet, combined with its central thickness T' accounting for 5.2% to 6.1% of the total optical length (TTL), provides sufficient material path difference for the projection lens, effectively compensating for the axial chromatic aberration produced by the front positive lens group, namely, the first lens 1. This design ensures that the projection lens module maintains chromatic aberration balance across a wide wavelength band (e.g., 455nm to 630nm), improving color reproduction accuracy.

[0095] The rational control of the center thickness T' of the triplet maximizes the dispersion correction capability at the cemented interface. This design helps reduce the dispersion of light when passing through materials with different refractive indices, thereby improving overall imaging quality.

[0096] If T' / TTL is less than 5.2%, the center thickness of the triplet is insufficient, which will lead to insufficient chromatic aberration correction and affect the color performance of the projected image. If T' / TTL is greater than 6.1%, the center thickness of the triplet is too thick, which may introduce additional spherical aberration and also have a negative impact on image quality.

[0097] In this example, the ratio of the triplet's center thickness (T') relative to the total optical length (TTL) of the projection lens module allows it to maintain negative optical power while simultaneously correcting for both field curvature and astigmatism. This design improves image clarity at the edges of the field of view, a benefit quantified by optimizing the MTF value.

[0098] By precisely controlling the ratio of the center thickness T' of the triplet lens to the TTL, this application avoids the problem of excessively increasing the number of lenses to correct chromatic aberration in traditional optical architecture designs. This not only helps maintain the compactness of the projection lens module (for example, the TTL is approximately 129mm, and the maximum aperture is only 25.6mm), but also reduces manufacturing cost and complexity.

[0099] It should be noted that if T' / TTL is less than 5.2%, additional lenses are required to compensate for chromatic aberration, which increases the volume and weight of the projection lens module. If T' / TTL is greater than 6.1%, the volume of the first lens assembly expands, compromising overall compactness. Therefore, the design in this application strikes a good balance between chromatic aberration correction and compactness.

[0100] Furthermore, the control of the central thickness T' of the triplet lens forms a synergistic design with the position of the aperture 12 (located between it and the fifth lens). This design ensures that the diameter of the light beam at the aperture 12 matches the clear aperture of the second lens group, thereby optimizing the optical path layout and imaging performance.

[0101] In summary, the center thickness T' of the triplet lens in the example of this application meets the design condition of 5.2%<T' / TTL<6.1%, which brings significant optical performance improvement to the projection lens module, including effective chromatic aberration correction, optimized imaging quality, compact design, and coordinated design with the aperture position.

[0102] In some examples of this application, see Figure 2 In the triplet lens, the second lens 2 and the fourth lens 4 have positive power, the third lens 3 has negative power, and the refractive indexes of the second lens 2 and the fourth lens 4 are both lower than the refractive index of the third lens 3. The triplet lens satisfies the following: 4.8<(T2+T4) / T3<6.1, where T2 is the center thickness of the second lens 2, T3 is the center thickness of the third lens 3, and T4 is the center thickness of the fourth lens 4.

[0103] The triplet lens, through its alternating arrangement of positive and negative optical powers (e.g., positive-negative-positive) and the combination of materials with different refractive indices, effectively corrects both axial and lateral chromatic aberrations. The positive optical power lenses (second and fourth lenses 2 and 4) and the negative optical power lens (third lens 3) work together to offset the chromatic aberrations produced by light of different wavelengths passing through the lenses, thereby improving color reproduction accuracy.

[0104] Specifically, the triplet utilizes the positive optical power of the second and fourth lenses (2 and 4) combined with the negative optical power of the third lens (3), forming an effective chromatic aberration correction mechanism. The positive lenses (the second and fourth lenses (4)) dominate the base optical power, while the negative lens (the third lens (3)) creates a refractive index gradient with its high refractive index (e.g., 1.72-1.79) and the low refractive index (e.g., 1.49-1.62) of the positive lens. This creates a complementary light deflection at the cemented interface. This reverse dispersion significantly reduces axial chromatic aberration and lateral chromatic aberration, thereby improving color reproduction accuracy.

[0105] In this application's example, the thickness ratio of the triplet lens satisfies 4.8 < (T2 + T4) / T3 < 6.1. This design ensures that the negative lens, or third lens element (3), has sufficient volume to effectively correct chromatic aberration while avoiding the high-order spherical aberration introduced by excessive lens thickness. This precise thickness control not only enhances the clarity and sharpness of the projected image, but also significantly improves image quality in the peripheral field of view.

[0106] By controlling the thickness ratio, the triplet lens achieves the aberration correction effect equivalent to 4-5 independent lenses in a cemented structure of only 3 lenses. This efficient design not only shortens the overall optical length of the entire projection lens module, but also helps to achieve a more compact and lightweight projection device.

[0107] Furthermore, the triplet lens, as a whole, maintains fixed relative positions between its internal lenses. This structural stability reduces the risk of lens displacement due to mechanical vibration or temperature fluctuations. This helps maintain the stability of the projection lens module, ensuring that the quality of the projected image is not affected by external factors, thereby providing users with a more reliable and stable visual experience.

[0108] In summary, the triplet lens design in this application achieves efficient optical performance through the alternating arrangement of positive and negative optical powers, the ingenious combination of materials with different refractive indices, and precise thickness ratio control. This includes significant improvements in chromatic aberration correction, aberration correction, structural compactness, and stability. This design not only meets the projection equipment's requirements for high performance, miniaturization, and lightweighting, but also provides new insights and directions for the development of projection technology.

[0109] In some examples of the present application, the air interval between the aperture 12 and the fourth lens 4 is L1, and the air interval between the aperture 12 and the fifth lens 5 is L2, satisfying the relationship: 1.8 <L2 / L1<2.4。

[0110] By constraining the ratio of L2 to L1, the position of the aperture 12 is adjusted closer to the first lens group (which includes a combination of positive and negative power lenses). This helps optimize pupil matching between the first lens group and the second lens group (which includes lenses with symmetrically distributed positive and negative power). This layout ensures that aberrations generated by the first lens group are effectively compensated by the second lens group, particularly achieving a more uniform angle of incidence at the edges of the field of view, significantly reducing astigmatism and coma.

[0111] Precisely controlling the air interval ratio between the aperture 12, the fourth lens 4, and the fifth lens 5 optimizes the optical path layout, enabling light to propagate more smoothly through the lenses. This optimization reduces light scattering and loss, thereby enhancing the brightness and contrast of the projected image. Meanwhile, a reasonable air interval ratio (i.e., 1.8 < L2 / L1 < 2.4) helps reduce the generation of aberrations (such as spherical aberration, coma, etc.), allowing light to project a clearer and sharper image, improving the overall imaging quality of the projected image.

[0112] The L2 / L1 range provided in this example of the present application ensures that the aperture 12 is in the optimal position within the limited total optical length (TTL = 129 mm). The position of the aperture 12 directly affects the deflection angle of light. Within the range of 1.8 < L2 / L1 < 2.4, the projection ratio can be stabilized at 0.25 (for example, when the projection distance is 50 cm, the image width can reach 2 m), and the Offset is maintained at 140%, ensuring that the projected image is far from the projection lens module and avoiding occlusion.

[0113] By controlling the air interval ratio between the aperture 12 and the lenses on both sides (i.e., 1.8 < L2 / L1 < 2.4), it also helps to enhance the stability of the entire projection lens module. In addition, optimizing the air interval ratio helps to achieve a compact design of the projection lens module, which is particularly important for projection devices that require miniaturization and lightweight. The compact design not only saves space but also reduces manufacturing costs and improves the portability of the product.

[0114] In this example of the present application, by precisely constraining the ratio of L2 / L1, the optimization of the optical path layout of the projection lens module is achieved, improving the imaging quality, module stability, and promoting compact design.

[0115] In some examples of the present application, the air interval between the fifth lens 5 and the sixth lens 6 is L3, satisfying the relationship: 7 < TTL / (L2 + L3) < 9.4.

[0116] In the example provided by the present application, the air interval between the fifth lens 5 and the sixth lens 6 is defined as L3, and further constrained by 7 < TTL / (L2 + L3) < 9.4, where L2 is the air interval between the aperture 12 and the fifth lens 5, and TTL is the total optical length of the entire projection lens module. The following is a specific analysis of this constraint condition and its beneficial effects.

[0117] (1) Regarding the lower limit constraint TTL / (L2 + L3) > 7:

[0118] Prevent positive refractive power dispersion: This constraint ensures that the distance between the fifth lens 5 and the sixth lens 6 is not too large, thus avoiding excessive dispersion of positive refractive power in the lens group. The concentration of positive refractive power helps to converge light more effectively and reduce aberrations such as field curvature.

[0119] Optimize the optical path layout: By restricting the ratio of the sum of L2 and L3 to TTL, it can prompt the designer to arrange the lens positions more reasonably within a limited space, optimize the optical path, and improve the imaging quality.

[0120] (2) Regarding the upper limit constraint TTL / (L2 + L3) < 9.4:

[0121] Avoid stray light introduction: This constraint prevents the fifth lens 5 and the sixth lens 6 from being too close to each other, thus reducing the stray light that may be introduced due to too small lens spacing. Stray light will reduce the contrast and clarity of the image and affect the projection effect.

[0122] Maintain lens independence: Appropriate air gaps help to maintain the independence of each lens, reduce the mutual optical interference, and are more conducive to the correction of aberrations and the precise control of light.

[0123] (3) Balance the compactness and optical performance of the module:

[0124] By restricting the ratio of TTL / (L2 + L3), while maintaining the overall compactness of the projection lens module, it can ensure that there is enough air gap between the lenses to optimize the optical path layout. This balance is crucial for achieving a high-performance compact projection lens.

[0125] A reasonable air gap ratio helps to reduce the generation of various aberrations (such as spherical aberration, coma, field curvature, etc.), making the light reduce scattering and refraction errors when passing through the lens, thus forming a clearer and sharper image.

[0126] On the premise of meeting the optical performance requirements, by precisely controlling the ratio of TTL / (L2 + L3), a compact design of the projection lens module can be achieved. This is particularly important for projection devices that require miniaturization and lightweight. A compact design can not only save space but also reduce the manufacturing cost and improve the portability of the product.

[0127] In some examples of this application, see Figure 5 , the angle between the tangent at the maximum aperture of the image side of the fifth lens 5 and the optical axis is A5, and the angle between the tangent at the maximum aperture of the object side of the fifth lens 5 and the optical axis is A6, satisfying the relationship: 5° < A6 - A5 < 25° and 60° < (A5 + A6) / 2 < 75°.

[0128] In the examples provided in this application, see Figure 5 The angles A5 and A6 between the tangents at the maximum apertures of the image side and object side of the fifth lens 5 and the optical axis satisfy the relationship: 5° < A6 - A5 < 25° and 60° < (A5 + A6) / 2 < 75°. This design can bring the following beneficial effects to the projection lens module of the present application by precisely controlling the surface shape of the fifth lens 5:

[0129] (1) Optimize the incident and exit angles of light:

[0130] Angle difference control: By restricting the range of A6 - A5, a reasonable angle difference is ensured between the tangents at the maximum apertures of the image side and object side of the fifth lens 5 and the optical axis. This design helps to optimize the incident and exit angles of light on the surface of the fifth lens 5, reducing light reflection and scattering caused by improper angles, thereby improving the utilization rate of light.

[0131] Average angle constraint: At the same time, the range constraint of (A5 + A6) / 2 further ensures that the average value of the angles between the tangents of the two surfaces of the fifth lens 5 and the optical axis is within an interval conducive to light convergence and imaging. This design helps the light to converge more smoothly onto the imaging surface when passing through the fifth lens 5, thereby improving the imaging quality.

[0132] (2) Contribute to reducing the aberration of the module:

[0133] Reasonable settings of the angles A5 and A6 are very important for reducing aberrations such as spherical aberration and coma. By controlling the incident and exit angles of light on the surface of the fifth lens 5, the light can form a more accurate and clear image point on the imaging surface, thereby improving the sharpness and contrast of the image.

[0134] The combined action of the double-parameter constraints of A6 - A5 and (A5 + A6) / 2 on aberration control enables effective correction of spherical aberration and coma and further optimization of higher-order aberrations such as field curvature under the optical conditions of ultra-short focal length and large Offset.

[0135] (3) Improve the imaging performance:

[0136] The above angle constraints not only optimize the light propagation path but also significantly improve the overall imaging performance of the projection lens module, including brightness, contrast, and color reproduction. By reducing light loss and scattering, the projection image can present a brighter and more vivid effect.

[0137] In particular, under the optical conditions of ultra-short focal length (projection ratio 0.25) and large Offset (140%), the angle A5 design of the fifth lens 5 achieves synchronous optimization of spherical aberration, coma, and field curvature through double-parameter constraints, ensuring the high-performance performance of the projection lens module in a complex optical environment.

[0138] In summary, the design of the angle A5 of the fifth lens element 5 achieves precise control of the incident and exit angles of light through dual parameter constraints (A6-A5 and the average angle), effectively reducing aberrations and significantly improving the overall imaging performance of the projection lens module. This design demonstrates outstanding performance advantages in ultra-short-throw, large-offset projection lens modules.

[0139] In some examples of this application, see Figure 2 The sag height of the sixth lens 6 at the maximum aperture on the image side is S3, and the sag height of the sixth lens 6 at the maximum aperture on the object side is S4, which satisfies the relationship: 1.4 <S3 / S4<2.2。

[0140] In the example provided in this application, the sag ratio constraint causes the sixth lens 6 to present an “asymmetric biconvex” structure.

[0141] Regarding the lower limit constraint (i.e., S3 / S4 > 1.4): The curvature of the image-side surface of the sixth lens element (6) is greater than the curvature of the object-side surface. This design helps compensate for the distortion introduced by the preceding lens group (particularly the fifth lens element (5)). The greater curvature of the image-side surface ensures that light passing through the sixth lens element (6) is properly corrected, thereby reducing distortion in the overall module.

[0142] The upper limit constraint (i.e., S3 / S4 < 2.2) prevents excessive difference in curvature between the two surfaces of the sixth lens element 6, which could introduce undesirable optical effects such as astigmatism. By controlling the ratio of S3 to S4, the sixth lens element 6 maintains sufficient correction capability without compromising image quality due to excessive curvature differences.

[0143] By controlling the ratio of S3 to S4, the surface shape of the sixth lens 6 can be precisely controlled, thereby optimizing the light propagation path within the sixth lens 6. This design helps reduce light scattering and reflection within the lens, improving light utilization and ultimately enhancing image quality. Light can pass through the lens more smoothly, reducing energy loss and resulting in brighter and clearer projection images.

[0144] At large fields of view (e.g., 72° to 76°), the aforementioned sag ratio constraints allow the projection lens module to simultaneously optimize distortion, astigmatism, and illumination uniformity. This means that the projected image maintains high clarity and uniformity across the wide field of view, meeting user demands for high-quality projection.

[0145] In some examples of this application, see Figure 4, the included angle between the tangent line at the maximum aperture of the object side of the sixth lens 6 and the optical axis is A3, and the included angle between the tangent line at the maximum aperture of the image side of the sixth lens 6 and the optical axis is A4, satisfying the relationship: 170° < A3 + A4 < 190° and 10° < A3 - A4 < 30°.

[0146] In the example provided in the present application, the included angles A3 and A4 between the tangent lines at the maximum apertures of the object side and the image side of the sixth lens 6 and the optical axis satisfy the relational expressions: 170° < A3 + A4 < 190° and 10° < A3 - A4 < 30°. This design precisely controls the edge shape of the sixth lens 6.

[0147] By setting the sum of A3 and A4 to be between 170° and 190°, it is ensured that the sixth lens 6 has reasonable tilt angles on the object side and the image side, which helps the light to converge more effectively onto the imaging surface when passing through the sixth lens 6. This design reduces the scattering of light, improves the utilization rate of light, and thus enhances the brightness and clarity of the projection lens.

[0148] The design with the difference between A3 and A4 being between 10° and 30° helps to control the aberrations generated by the sixth lens 6, especially field curvature and distortion. Field curvature will cause a decrease in the clarity of the image edge, while distortion will cause the image to be distorted. By controlling the difference between these two angles, these adverse effects can be significantly reduced, making the projection image flatter and more realistic.

[0149] In the example provided in the present application, through the optimization of the above two angle relationships, the sixth lens 6 can better cooperate with other lenses in the projection lens module to jointly improve the overall imaging quality. This includes improving the resolution, contrast, and color reproduction of the image, making the projection image more delicate and vivid.

[0150] The projection lens module design in the present application can be used for large field-of-view (72° - 76°) projection, and the optimization of the angle relationship of the sixth lens 6 is precisely to meet this requirement. By precisely controlling A3 and A4, it can be ensured that under large field-of-view conditions, the projection image can still maintain high clarity and uniformity, meeting the user's demand for high-quality projection effects.

[0151] In summary, the specific relationship between the included angles A3 and A4 of the tangent lines at the maximum apertures of the object side and the image side of the sixth lens 6 and the optical axis brings significant beneficial effects to the projection lens module of the present application by optimizing the light convergence ability, controlling aberrations, improving imaging quality, enhancing the stability of the module, and meeting the large field-of-view requirements.

[0152] In some examples of the present application, the second lens group satisfies the relationship: 2.9<(T7+T8) / (T9+T10)<3.6, where T7 is the center thickness of the seventh lens 7, T8 is the center thickness of the eighth lens 8, T9 is the center thickness of the ninth lens 9, and T10 is the center thickness of the tenth lens 10.

[0153] By setting the ratio of the sum of the center thicknesses of the seventh and eighth lenses (T7 + T8) to the sum of the center thicknesses of the ninth and tenth lenses (T9 + T10), chromatic aberration can be more effectively corrected. Chromatic aberration is a common aberration in optical systems that causes light of different wavelengths to have different focal points on the imaging surface, thereby affecting image clarity and color reproduction. The example provided in this application, by precisely controlling the thickness ratio of the four specific lenses in the second lens group, helps reduce chromatic aberration, resulting in clearer projected images and more accurate colors.

[0154] By optimizing the thickness distribution of these four lenses, the scattering and reflection of light within these lenses can be reduced, improving light utilization. At the same time, this design also helps to reduce other types of aberrations, such as spherical aberration and coma, thereby presenting a clearer and more accurate image.

[0155] The total optical length (TTL) of a projection lens module is closely related to the center thickness of each lens. By optimizing the center thickness ratio of some lenses in the second lens group, this application helps find the optimal balance between the total optical length and performance of the projection lens module, meeting the needs of practical applications.

[0156] The projection lens module of the present embodiment is designed for ultra-short-throw projection, which places high demands on various performance indicators. By setting the thickness ratio of the second lens group, it can better meet the requirements of ultra-short-throw projection. This design helps reduce the projection distance, improve the brightness and clarity of the projected image, and maintain a large offset value to prevent the projected image from being obscured by the projection device body.

[0157] In some examples of the present application, the sag height of the eighth lens 8 at the maximum aperture on the image side is S1, and the sag height of the eighth lens 8 at the maximum aperture on the object side is S2, which satisfies the relationship: 2.9 <S2 / S1<3.8。

[0158] By controlling the ratio of S2 to S1, the surface shape of the eighth lens element 8 is precisely controlled. This specific shape helps correct aberrations in the projection lens module, particularly spherical aberration and coma. In other words, by optimizing the S2 / S1 ratio, the eighth lens element 8 can more effectively correct these aberrations, improving image quality.

[0159] According to the example provided by this application, the sagittal height ratio design of the eighth lens 8 enables the reasonable matching of the curvatures of its object side and image side, which helps to enhance the converging ability of light when passing through the eighth lens 8. The light can be more accurately focused on the imaging surface, thereby improving the brightness and clarity of the projection image.

[0160] By controlling the sagittal height ratio of the eighth lens 8, the distribution of light on the imaging surface can be made more uniform. This helps to reduce the uneven brightness phenomenon in the projection image and improve the overall imaging uniformity.

[0161] The projection lens module design of this application can be used for large field-of-view (72° - 76°) projection, and the sagittal height ratio design of the eighth lens 8 helps to meet this requirement. By optimizing the shape of the lens, the light can maintain good imaging quality within a wider field of view, meeting the user's need for large field-of-view projection.

[0162] In addition, by controlling the sagittal height ratio of the eighth lens 8, while ensuring the performance of the projection lens module, it helps to optimize the overall optical length of the projection lens module. This compact design helps to reduce the volume and weight of the projection device, improving its portability and practicality.

[0163] In some examples of this application, refer to Figure 3 , the included angle between the tangent line at the maximum aperture of the object side of the tenth lens 10 and the optical axis is A1, and the included angle between the tangent line at the maximum aperture of the image side of the tenth lens 10 and the optical axis is A2, satisfying the relationship: 14° < A1 - A2 < 26° and 0.6 < A2 / A1 < 0.85.

[0164] Refer to Figure 3 , by setting the difference between A1 and A2 to be between 14° and 26°, and the ratio of A2 to A1 to be between 0.6 and 0.85, the tenth lens 10 can more effectively control the propagation path of light. This design helps to reduce the scattering and reflection of light inside the tenth lens 10, improve the utilization rate of light, and thus enhance the imaging brightness and clarity of the projection lens module.

[0165] According to the specific relationship between A1 and A2 provided in this example of this application, it helps to control the aberrations generated by the tenth lens 10, especially astigmatism and distortion. Astigmatism will cause the image to have inconsistent clarity in different directions, while distortion will cause the image to be distorted. By controlling the relationship between these two angles, these adverse effects can be significantly reduced, making the projection image flatter and more realistic. <The optimized angular relationship enables the tenth lens 10 to better cooperate with other lenses in the projection lens module to improve the overall imaging quality. This includes improving the image resolution, contrast, and color reproduction, making the projected image more detailed and vivid.

[0167] The projection lens module in this application is designed for projection conditions with a wide field of view (72°-76°) and a high offset (140%). The optimized angle relationship of the tenth lens 10 is precisely designed to meet this requirement. By precisely controlling A1 and A2, the projected image maintains high clarity and uniformity even under wide field of view and high offset conditions, meeting user demands for high-quality projection.

[0168] In some examples of this application, see Figure 1 and Figure 2 The projection lens module further includes a prism 14, a glass plate 15 and a display unit 16, which are arranged in sequence on the image side of the first lens 1; the projection lens module further includes an aspherical reflection bowl 13 on the object side of the eleventh lens 11; the total optical length TTL of the projection lens module and the maximum aperture D1 of the lens in the projection lens module satisfy the relationship: 4.5<TTL / D1<5.3.

[0169] By controlling the ratio of the total optical length TTL of the projection lens module and the maximum aperture D1 of the projection lens, that is, 4.5<TTL / D1<5.3, a compact design of the projection lens module is achieved. Figure 2 , the eleventh lens 11 away from the display unit 16 has the largest aperture.

[0170] In the example of this application, the sequential arrangement of the prism 14, the glass plate 15, and the display unit 16, along with the addition of the aspheric reflective bowl 13, optimizes the light propagation path. The glass plate 15 can be used to protect the display unit 16 or shape the light, while the display unit is the source of the projected image. The aspheric reflective bowl 13 can more effectively reflect and focus light, reducing aberrations and improving image quality.

[0171] The compact system design reduces light loss during propagation, improving projection efficiency. Furthermore, the use of the aspherical reflector bowl 13 also helps enhance light convergence, thereby increasing the brightness of the projected image. This is particularly important when using a projector in bright environments.

[0172] In some examples of the present application, the effective focal length of each lens in the projection lens module satisfies:

[0173] The effective focal length of the first lens 1 is F1, 9mm≤F1≤14mm;

[0174] The effective focal length of the triplet lens is F', -75mm≤F'≤-55mm;

[0175] The effective focal length of the fifth lens 5 is F5, 50mm≤F5≤70mm;

[0176] The effective focal length of the sixth lens 6 is F6, 80mm≤F6≤105mm;

[0177] The effective focal length of the seventh lens 7 is F7, 39mm≤F7≤52mm;

[0178] The effective focal length of the eighth lens 8 is F8, 40mm≤F8≤53mm;

[0179] The effective focal length of the ninth lens 9 is F9, -80mm≤F9≤-60mm;

[0180] The effective focal length of the tenth lens 10 is F10, -75mm≤F10≤-55mm;

[0181] The effective focal length of the eleventh lens 11 is F11, -20mm≤F11≤-14mm;

[0182] The first lens 1 is a glass aspheric lens, the eleventh lens 11 is a plastic aspheric lens, and the remaining lenses are all glass spherical lenses.

[0183] In the example provided herein, the effective focal length F1 of the first lens 1 is within the range of 9mm ≤ F1 ≤ 14mm. As the first lens in the projection lens module, its effective focal length is set within a relatively short range, which helps to initially converge light and lay the foundation for light propagation by subsequent lenses. The use of glass aspherical lenses can further reduce aberrations and improve imaging quality.

[0184] In the examples provided herein, the effective focal length F' of the triplet lens is in the range of -75mm ≤ F' ≤ -55mm. The triplet lens is used to correct chromatic aberration, and its negative effective focal length indicates that it diverges light in the system, helping to correct for chromatic dispersion during light propagation.

[0185] In the example provided herein, the effective focal length F5 of the fifth lens element 5 is in the range of 50 mm ≤ F5 ≤ 70 mm. As a positive lens in the second lens group, its effective focal length is within a moderate range, helping to further converge light and correct system aberrations.

[0186] In the example provided herein, the effective focal length F6 of the sixth lens element 6 is in the range of 80 mm ≤ F6 ≤ 105 mm. The longer effective focal length of the sixth lens element 6 indicates that it has a stronger light-converging effect in the module, potentially used to form a sharp image point or correct specific aberrations.

[0187] In the example provided herein, the effective focal length F7 of the seventh lens element 7 is within the range of 39mm ≤ F7 ≤ 52mm. As a positive lens in the second lens group, its moderate effective focal length contributes to smooth light propagation through the system and helps correct for aberrations such as distortion.

[0188] In the example provided herein, the effective focal length F8 of the eighth lens element 8 is in the range of 40 mm ≤ F8 ≤ 53 mm. The eighth lens element 8 is also a positive lens, and its effective focal length range is similar to that of the seventh lens element 7, working together to optimize light propagation and image quality.

[0189] In the example provided herein, the effective focal length F9 of the ninth lens element 9 is in the range of -80mm ≤ F9 ≤ -60mm. As a negative lens, the ninth lens element 9 has a long, negative effective focal length, indicating that it has a strong light diverging effect in the module, potentially used to correct module aberrations or adjust light propagation paths.

[0190] In the example provided in this application, the effective focal length F10 of the tenth lens 10 is in the range of -75mm≤F10≤-55mm. The tenth lens 10 is also a negative lens, and its effective focal length range helps to further correct the chromatic aberration or other aberrations of the system.

[0191] In the example provided herein, the effective focal length F11 of the eleventh lens element 11 is within the range of -20mm ≤ F11 ≤ -14mm. As the final lens in the projection lens module, and a plastic aspherical lens, its negative effective focal length facilitates final correction and adjustment before light is emitted, ensuring clarity and uniformity of the projected image.

[0192] In addition, the first lens 1 is a glass aspherical lens. Glass has advantages such as high refractive index and low dispersion. The aspherical design can further reduce aberrations and improve imaging quality.

[0193] The eleventh lens 11 is a plastic aspheric lens. Plastic is relatively light, low-cost, and easy to process into an aspheric shape. Using a plastic aspheric lens at the end of the projection lens module of this application can reduce the overall weight while maintaining good imaging performance.

[0194] The remaining lenses are all glass spherical lenses. Glass spherical lenses have stable optical performance and a high refractive index. In the projection lens module of this application, the glass spherical lens works together with the glass aspherical lens and the plastic aspherical lens to achieve optimal optical performance.

[0195] For a specific example, see Figure 2 The main parameters of the projection lens module provided in the embodiment of the present application are as follows:

[0196] Focal length: 1.27mm;

[0197] Throw ratio: 0.25;

[0198] Relative aperture: 1 / 1.71;

[0199] Offset: 140%

[0200] Pixel size: 5.4 μm;

[0201] Distortion: <5%

[0202] Relative illumination: >65%

[0203] Working band: 455-630nm;

[0204] Field of view: 72°~76°;

[0205] Image size: 8.5smm~9.2mm.

[0206] Focal length is one of the fundamental parameters of a projection lens module, determining the distance at which it can focus light. In this example, the focal length of 1.27mm is very short, which facilitates ultra-short-throw projection, enabling the creation of large images from very short distances.

[0207] Throw ratio is a key specification for projection lens modules, representing the ratio of projected image width to projection distance. A smaller throw ratio indicates a larger image at the same projection distance. A throw ratio of 0.25 indicates excellent ultra-short-throw performance.

[0208] Relative aperture is the ratio of the amount of light entering the lens to the focal length. It affects the light transmission capacity and image brightness of the projection lens module. A larger relative aperture means that the projection lens can capture more light, thereby improving the brightness of the projected image.

[0209] 140% Offset means that the projected image will be away from the projector lens module, see Figure 1 This reduces the possibility of being blocked by the projection device body and improves the convenience of use.

[0210] Pixel size refers to the size of a single pixel on an imaging unit (such as a display chip). A pixel size of 5.4μm means the imaging unit has a high pixel density, which helps achieve high-resolution projection images.

[0211] Distortion is the deformation that occurs when a lens forms an image. A distortion rate of less than 5% indicates that the projection lens module maintains good shape accuracy during imaging, reducing distortion and deformation of the image.

[0212] Relative illumination is the ratio of the brightness at the center to the edges of the projected image. A relative illumination greater than 65% means the brightness of the projected image is more evenly distributed, with no noticeable drop in brightness at the edges, improving the overall visual effect.

[0213] The operating wavelength is the range of light wavelengths within which the projection lens module can operate effectively. The 455-630nm operating wavelength covers most of the visible light range, ensuring stable performance of the lens under different lighting conditions.

[0214] The 72°~76° field of view angle means that the projection lens module can project a wider image, which is suitable for large-screen projection needs.

[0215] The image plane size of 8.5mm~9.2mm combined with the pixel size determines the resolution and detail expression ability of the projected image.

[0216] In summary, the projection lens module provided in the embodiments of this application achieves ultra-short throw, high brightness, high resolution, low distortion, and uniform illumination by precisely setting a series of key optical parameters. The optimized combination of these parameters enables the lens module to excel in a variety of application scenarios, including home viewing and conference room presentations.

[0217] The projection lens module of the present application is described below through Examples 1 to 5.

[0218] Example 1

[0219] See also Figure 6 The projection lens module provided in Example 1 includes, from the image side to the object side, a display unit 16, a glass plate 15, a prism 14, a first lens group, an aperture 12, a second lens group, and an aspherical reflection bowl 13;

[0220] 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, wherein:

[0221] The first lens 1 is an aspheric lens with positive refractive power;

[0222] The second lens 2, the third lens 3 and the fourth lens 4 are cemented together to form a triplet lens, and the triplet lens has a negative optical power as a whole;

[0223] The second lens group includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10 and an eleventh lens 11 arranged in sequence, wherein:

[0224] The fifth lens 5 to the eighth lens 8 have positive refractive power;

[0225] The ninth lens 9 to the eleventh lens 11 have negative optical power;

[0226] The aperture 12 is located between the triplet lens and the fifth lens 5 .

[0227] See also Figure 6 , Figure 6 Some optical parameters of the projection lens module are shown in Table 1 below.

[0228] Table 1

[0229]

[0230] Figure 6 The aspheric parameters of the projection lens module shown are shown in Table 2.

[0231] Table 2

[0232]

[0233] Example 2

[0234] See also Figure 7 The projection lens module of embodiment 2 includes a display unit 16, a glass plate 15, a prism 14, a first lens group, an aperture 12, a second lens group and an aspherical reflection bowl 13 in order from the image side to the object side;

[0235] 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, wherein:

[0236] The first lens 1 is an aspheric lens with positive refractive power;

[0237] The second lens 2, the third lens 3 and the fourth lens 4 are cemented together to form a triplet lens, and the triplet lens has a negative optical power as a whole;

[0238] The second lens group includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10 and an eleventh lens 11 arranged in sequence, wherein:

[0239] The fifth lens 5 to the eighth lens 8 have positive refractive power;

[0240] The ninth lens 9 to the eleventh lens 11 have negative optical power;

[0241] The aperture 12 is located between the triplet lens and the fifth lens 5 .

[0242] See also Figure 7 , Figure 7 Some optical parameters of the projection lens module are shown in Table 3 below.

[0243] Table 3

[0244]

[0245] The aspheric parameters of the projection lens module provided in Example 2 are shown in Table 4.

[0246] Table 4

[0247]

[0248] Example 3

[0249] See also Figure 8 The projection lens module provided in Example 3 includes, from the image side to the object side, a display unit 16, a glass plate 15, a prism 14, a first lens group, an aperture 12, a second lens group, and an aspherical reflection bowl 13;

[0250] 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, wherein:

[0251] The first lens 1 is an aspheric lens with positive refractive power;

[0252] The second lens 2, the third lens 3 and the fourth lens 4 are cemented together to form a triplet lens, and the triplet lens has a negative optical power as a whole;

[0253] The second lens group includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10 and an eleventh lens 11 arranged in sequence, wherein:

[0254] The fifth lens 5 to the eighth lens 8 have positive refractive power;

[0255] The ninth lens 9 to the eleventh lens 11 have negative optical power;

[0256] The aperture 12 is located between the triplet lens and the fifth lens 5 .

[0257] See also Figure 8 , Figure 8 Some optical parameters of the projection lens module are shown in Table 5 below.

[0258] Table 5

[0259]

[0260] The aspheric parameters of the projection lens module provided in Example 3 are shown in Table 6.

[0261] Table 6

[0262]

[0263] Example 4

[0264] See also Figure 9 The projection lens module provided in Example 4 includes, from the image side to the object side, a display unit 16, a glass plate 15, a prism 14, a first lens group, an aperture 12, a second lens group, and an aspherical reflection bowl 13;

[0265] 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, wherein:

[0266] The first lens 1 is an aspheric lens with positive refractive power;

[0267] The second lens 2, the third lens 3 and the fourth lens 4 are cemented together to form a triplet lens, and the triplet lens has a negative optical power as a whole;

[0268] The second lens group includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10 and an eleventh lens 11 arranged in sequence, wherein:

[0269] The fifth lens 5 to the eighth lens 8 have positive refractive power;

[0270] The ninth lens 9 to the eleventh lens 11 have negative optical power;

[0271] The aperture 12 is located between the triplet lens and the fifth lens 5 .

[0272] See also Figure 9 , Figure 9Some optical parameters of the projection lens module are shown in Table 7 below.

[0273] Table 7

[0274]

[0275] The aspheric parameters of the projection lens module provided in Example 4 are shown in Table 8.

[0276] Table 8

[0277]

[0278] Example 5

[0279] See also Figure 10 The projection lens module provided in Example 5 includes, from the image side to the object side, a display unit 16, a glass plate 15, a prism 14, a first lens group, an aperture 12, a second lens group, and an aspherical reflection bowl 13;

[0280] 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, wherein:

[0281] The first lens 1 is an aspheric lens with positive refractive power;

[0282] The second lens 2, the third lens 3 and the fourth lens 4 are cemented together to form a triplet lens, and the triplet lens has a negative optical power as a whole;

[0283] The second lens group includes a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10 and an eleventh lens 11 arranged in sequence, wherein:

[0284] The fifth lens 5 to the eighth lens 8 have positive refractive power;

[0285] The ninth lens 9 to the eleventh lens 11 have negative optical power;

[0286] The aperture 12 is located between the triplet lens and the fifth lens 5 .

[0287] See also Figure 10 , Figure 10 Some optical parameters of the projection lens module are shown in Table 9 below.

[0288] Table 9

[0289]

[0290] The aspheric parameters of the projection lens module provided in Example 5 are shown in Table 10.

[0291] Table 10

[0292]

[0293] The optical performance of the projection lens modules provided in Examples 1 to 5 above is as follows:

[0294] See also Figure 11 ,from Figure 11 As can be seen, the absolute value of the distortion of the projection lens module is less than 5%. This means that the projection lens module provided by the embodiment of the present application can maintain a good image shape and proportion during the imaging process, avoiding image distortion and deformation. This excellent distortion performance is particularly important for projection displays, ensuring that the images viewed by the audience are more realistic and natural.

[0295] See also Figure 12 , Figure 12 This is the MTF diagram of the projection lens module. The MTF is >0.5 at 93lp / mm.

[0296] In other words, the projection lens module provided in this application has an MTF value greater than 0.5 at a spatial frequency of 93 lp / mm. This means that even when processing details at higher spatial frequencies, the projection lens module can still maintain a high contrast transmission efficiency, ensuring that the detailed information in the projected image is presented clearly and sharply. The high MTF value not only improves the clarity of the image, but also enhances the color saturation and layering, making the projected image more vivid and realistic.

[0297] The above analysis of distortion and MTF performance demonstrates that the projection lens module of this application exhibits excellent optical performance. An absolute distortion value of less than 5% ensures image authenticity and naturalness. An MTF greater than 0.5 at 93 lp / mm ensures the projection lens module's sharpness and detail resolution at high resolutions. These excellent optical properties make this projection lens module particularly suitable for applications requiring high image quality, such as home theaters and conference room projection.

[0298] According to another embodiment of the present application, a projection device is provided, comprising a housing and the projection lens module as described above.

[0299] The specific implementation of the projection device of the embodiment of the present application can refer to the various embodiments of the projection lens module described above, and therefore at least has all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0300] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0301] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A projection lens module, characterized in that: It successively includes a first lens group, an aperture (12), and a second lens group from the image side to the object side along the optical axis; 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, where: The first lens (1) is an aspherical lens with positive optical power, and the central thickness T1 thereof and the overall optical length TTL of the projection lens module satisfy: 2.4% < T1 / TTL < 3.1%; The second lens (2), the third lens (3), and the fourth lens (4) are cemented together to form a triplet lens, and the overall triplet lens has negative optical power; The second lens group includes a fifth lens (5), a sixth lens (6), a seventh lens (7), an eighth lens (8), a ninth lens (9), a tenth lens (10), and an eleventh lens (11) arranged in sequence, where: The fifth lens (5) to the eighth lens (8) have positive optical power; The ninth lens (9) to the eleventh lens (11) have negative optical power; The aperture (12) is located between the triplet lens and the fifth lens (5).

2. The projection lens module according to claim 1, wherein: The central thickness T' of the triplet lens satisfies: 5.2% < T' / TTL < 6.1%.

3. The projection lens module according to claim 1 or 2, wherein: In the triplet lens: the second lens (2) and the fourth lens (4) have positive optical power, the third lens (3) has negative optical power, and the refractive indices of the second lens (2) and the fourth lens (4) are both lower than the refractive index of the third lens (3); The triplet lens satisfies: 4.8 < (T2 + T4) / T3 < 6.1, where T2 is the central thickness of the second lens (2), T3 is the central thickness of the third lens (3), and T4 is the central thickness of the fourth lens (4).

4. The projection lens module according to claim 1, wherein: The air gap between the aperture (12) and the fourth lens (4) is L1, and the air gap between the aperture (12) and the fifth lens (5) is L2, satisfying the relationship: 1.8 < L2 / L1 < 2.

4.

5. The projection lens module according to claim 4, wherein: The air gap between the fifth lens (5) and the sixth lens (6) is L3, satisfying the relationship: 7 < TTL / (L2 + L3) < 9.

4.

6. The projection lens module according to claim 1, 4 or 5, wherein: The angle between the tangent line at the maximum aperture of the image side of the fifth lens (5) and the optical axis is A5, and the angle between the tangent line at the maximum aperture of the object side of the fifth lens (5) and the optical axis is A6, satisfying the relationships: 5° < A6 - A5 < 25° and 60° < (A5 + A6) / 2 < 75°.

7. The projection lens module according to claim 1, 4 or 5, wherein: The sagittal height at the maximum aperture of the image side of the sixth lens (6) is S3, and the sagittal height at the maximum aperture of the object side of the sixth lens (6) is S4, satisfying the relationship: 1.4 < S3 / S4 < 2.

2.

8. The projection lens module according to claim 1, 4 or 5, wherein: The angle between the tangent line at the maximum aperture of the object side of the sixth lens (6) and the optical axis is A3, and the angle between the tangent line at the maximum aperture of the image side of the sixth lens (6) and the optical axis is A4, satisfying the relationships: 170° < A3 + A4 < 190° and 10° < A3 - A4 < 30°.

9. The projection lens module according to claim 1, wherein: The second lens group satisfies the relationship: 2.9 < (T7 + T8) / (T9 + T10) < 3.6, where T7 is the central thickness of the seventh lens (7), T8 is the central thickness of the eighth lens (8), T9 is the central thickness of the ninth lens (9), and T10 is the central thickness of the tenth lens (10).

10. The projection lens module according to claim 1 or 9, wherein: The sagittal height at the maximum aperture of the image side of the eighth lens (8) is S1, and the sagittal height at the maximum aperture of its object side is S2, satisfying the relationship: 2.9 < S2 / S1 < 3.

8.

11. The projection lens module according to claim 1 or 9, wherein: The angle between the tangent line at the maximum aperture of the object side of the tenth lens (10) and the optical axis is A1, and the angle between the tangent line at the maximum aperture of the image side of the tenth lens (10) and the optical axis is A2, satisfying the relationships: 14° < A1 - A2 < 26° and 0.6 < A2 / A1 < 0.

85.

12. The projection lens module according to claim 1, wherein: The projection lens module further includes a prism (14), a glass plate (15), and a display unit (16) that are sequentially arranged on the image side of the first lens (1); The projection lens module further includes an aspherical reflector bowl (13) on the object side of the eleventh lens (11); The total optical length TTL of the projection lens module and the maximum aperture D of the lenses in the projection lens module satisfy the relationship: 4.5 < TTL / D1 < 5.

3.

13. The projection lens module according to claim 12, wherein: The effective focal lengths of the lenses in the projection lens module satisfy: The effective focal length of the first lens (1) is F1, 9 mm ≤ F1 ≤ 14 mm; The effective focal length of the triplet lens is F', -75 mm ≤ F' ≤ -55 mm; The effective focal length of the fifth lens (5) is F5, 50 mm ≤ F5 ≤ 70 mm; The effective focal length of the sixth lens (6) is F6, 80 mm ≤ F6 ≤ 105 mm; The effective focal length of the seventh lens (7) is F7, 39 mm ≤ F7 ≤ 52 mm; The effective focal length of the eighth lens (8) is F8, 40 mm ≤ F8 ≤ 53 mm; The effective focal length of the ninth lens (9) is F9, -80 mm ≤ F9 ≤ -60 mm; The effective focal length of the tenth lens (10) is F10, -75 mm ≤ F10 ≤ -55 mm; The effective focal length of the eleventh lens (11) is F11, -20 mm ≤ F11 ≤ -14 mm; Among them, the first lens (1) is a glass aspherical lens, the eleventh lens (11) is a plastic aspherical lens, and the remaining lenses are all glass spherical lenses.

14. A projection device, characterized in that: Including: A housing; And The projection lens module according to any one of claims 1 - 13.

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