Optical projection system and projector

Abstract

The application discloses an optical projection system and a projector, and relates to the technical field of optical systems, wherein the optical projection system has a first side and a second side which are oppositely arranged along the direction of an optical axis, and the optical projection system is sequentially provided with an illumination device, an adjusting lens group and a reflecting mirror from the first side to the second side; the adjusting lens group comprises first to fourth lens groups which are sequentially arranged from the first side to the second side; the second to fourth lens groups are movably arranged along the direction of the optical axis; the optical power of the first lens group and the second lens group is positive, and the optical power of the third lens group and the fourth lens group is negative; the projection ratio of the optical projection system is less than or equal to 0.18, the aperture number F is greater than or equal to 2.2, and the luminous flux is greater than or equal to 4000 lm. The technical scheme provided by the application breaks through the performance bottleneck of the existing super-short-focus projection in the projection ratio, brightness and aperture number by means of the positive and negative matching of the optical power of the lens groups and the movable design of the lens groups, and the technical effects of simultaneously satisfying the low projection ratio, large aperture and high luminous flux are achieved.

Description

Technical Field

[0001] This invention relates to the field of optical system technology, and in particular to an optical projection system and a projector. Background Technology

[0002] An ultra-short throw projector is a projector with a very small ratio between the distance between the projector and the screen and the screen size. It can project a larger image from a very short distance. The smaller the throw ratio, the larger the corresponding field of view.

[0003] Most ultra-short throw projectors on the market have a throw ratio of 0.22 or higher, with only a few having a throw ratio of 0.2. They also tend to have low brightness, generally below 2000lm, and cannot simultaneously meet the requirements of high brightness, large aperture, and low transmittance. Summary of the Invention

[0004] The main objective of this invention is to provide an optical projection system and projector that simultaneously meets the requirements of high brightness, large aperture, and low transmittance.

[0005] To achieve the above objectives, the present invention proposes an optical projection system having a first side and a second side arranged opposite to each other along the optical axis. The optical projection system includes an illumination device, an adjustment mirror group, and a reflector arranged sequentially from the first side to the second side. The illumination device emits light towards the second side, the adjustment mirror group adjusts the light path and directs it towards the reflector, and the reflector reflects the light towards the first side for projection onto the first side.

[0006] The adjusting lens group includes a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially from the first side to the second side; the second lens group, the third lens group, and the fourth lens group are movably arranged along the optical axis direction, the optical power of the first lens group and the second lens group is positive, and the optical power of the third lens group and the fourth lens group is negative; The projection ratio of the optical projection system is less than or equal to 0.18, the aperture number F of the optical projection system is F≥2.2, and the luminous flux of the optical projection system is greater than or equal to 4000lm.

[0007] In one embodiment, the focal length of the first lens group is F1, where 20mm ≤ F1 ≤ 30mm; The focal length of the first lens group is F2, 70mm≤F2≤90mm; The focal length of the first lens group is F3, -50mm≤F3≤-30mm; The focal length of the first lens group is F4, -70mm≤F4≤-50mm.

[0008] In one embodiment, the first lens group includes, sequentially arranged from the first side to the second side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens; the focal length of the first lens is f1, 25≤f1≤35; the focal length of the second lens is f2, 25≤f2≤40; the focal length of the third lens is f3, 35≤f3≤45; and the focal length of the fourth lens is f4, -15≤f4≤-5. The focal length of the fifth lens is f5, 30≤f5≤40; the focal length of the sixth lens is f6, 15≤f6≤30; the focal length of the seventh lens is f7, -15≤f7≤-5; the focal length of the eighth lens is f8, 5≤f8≤20; the focal length of the ninth lens is f9, 5≤f9≤20; the focal length of the tenth lens is f10, -35≤f10≤-20; the focal length of the eleventh lens is f11, -20≤f11≤-10; and the focal length of the twelfth lens is f12, 50≤f12≤70. The second lens group includes a thirteenth lens, the focal length of which is f13, and 70≤f13≤90; The third lens group includes a fourteenth lens, a fifteenth lens, and a sixteenth lens arranged sequentially from the first side to the second side; the fourteenth lens has a focal length of f14, 50≤f14≤70; the fifteenth lens has a focal length of f15, -45≤f15≤-30; and the sixteenth lens has a focal length of f16, -50≤f16≤-30. The fourth lens group includes a seventeenth lens, the seventeenth lens having a focal length of f17, -70≤f17≤-50.

[0009] In one embodiment, the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the fourteenth lens, and the fifteenth lens are spherical lenses; The second lens, the thirteenth lens, the sixteenth lens, and the seventeenth lens are aspherical lenses.

[0010] In one embodiment, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens, and the fifteenth lens are glass lenses; The sixteenth lens and the seventeenth lens are plastic lenses.

[0011] In one embodiment, the third lens, the fourth lens, and the fifth lens are cemented together; the sixth lens, the seventh lens, and the eighth lens are cemented together; and the ninth lens and the tenth lens are cemented together.

[0012] In one embodiment, the Abbe number of the first lens is V1, where 15.0 ≤ v1 ≤ 30.0; The Abbe number of the second lens is V2, where 70.0 ≤ v2 ≤ 95.0; The Abbe number of the third lens is V3, where 70.0 ≤ v3 ≤ 95.0; The Abbe number of the fourth lens is V4, where 15.0 ≤ v4 ≤ 30.0; The Abbe number of the fifth lens is V5, where 60.0 ≤ v5 ≤ 90.0; The Abbe number of the sixth lens is V6, where 60.0 ≤ v6 ≤ 90.0; The Abbe number of the seventh lens is V7, where 20.0 ≤ v7 ≤ 35.0; The Abbe number of the eighth lens is V8, where 45.0 ≤ v8 ≤ 75.0; The Abbe number of the ninth lens is V9, where 20.0 ≤ v9 ≤ 45.0; The Abbe number of the tenth lens is V10, where 20.0 ≤ v10 ≤ 50.0; The Abbe number of the eleventh lens is V11, where 30.0 ≤ v11 ≤ 50.0; The Abbe number of the twelfth lens is V12, where 30.0 ≤ v12 ≤ 50.0; The Abbe number of the thirteenth lens is V13, where 30.0 ≤ v13 ≤ 50.0; The Abbe number of the fourteenth lens is V14, where 75.0 ≤ v14 ≤ 95.0; The Abbe number of the fifteenth lens is V15, where 20.0 ≤ v15 ≤ 35.0; The Abbe number of the sixteenth lens is V16, where 50.0 ≤ v16 ≤ 65.0; The Abbe number of the seventeenth lens is V17, where 50.0 ≤ v17 ≤ 65.0.

[0013] In one embodiment, the refractive index of the first lens is N1, where 1.80 ≤ n1 ≤ 2.00; The refractive index of the second lens is N2, where 1.45 ≤ n2 ≤ 1.65; The refractive index of the third lens is N3, where 1.45 ≤ n3 ≤ 1.65; The refractive index of the fourth lens is N4, where 1.85 ≤ n4 ≤ 2.10; The refractive index of the fifth lens is N5, where 1.45 ≤ n5 ≤ 1.65; The refractive index of the sixth lens is N6, where 1.45 ≤ n6 ≤ 1.65; The refractive index of the seventh lens is N7, where 1.80 ≤ n7 ≤ 1.95; The refractive index of the eighth lens is N8, where 1.45 ≤ n8 ≤ 1.60; The refractive index of the ninth lens is N9, where 1.55 ≤ n9 ≤ 1.85; The refractive index of the tenth lens is N10, where 1.70 ≤ n10 ≤ 1.90; The refractive index of the eleventh lens is N11, where 1.60 ≤ n11 ≤ 1.85; The refractive index of the twelfth lens is N12, 1.60≤n12≤1.85; The refractive index of the thirteenth lens is N13, where 1.55 ≤ n13 ≤ 1.80; The refractive index of the fourteenth lens is N14, where 1.45 ≤ n14 ≤ 1.60; The refractive index of the fifteenth lens is N15, where 1.75 ≤ n15 ≤ 1.95; The refractive index of the sixteenth lens is N16, where 1.45 ≤ n16 ≤ 1.60; The refractive index of the seventeenth lens is N17, where 1.45 ≤ n17 ≤ 1.60.

[0014] In one embodiment, the first lens group further includes an aperture stop, which is disposed between the eighth lens and the ninth lens; the total optical length of the optical projection system is TTL, TTL≤175.5mm, and the TV distortion of the optical projection system is less than or equal to 0.2%.

[0015] The present invention also proposes a projector, which includes an optical projection system having a first side and a second side arranged opposite to each other along the optical axis. The optical projection system includes an illumination device, an adjustment mirror group, and a reflector arranged sequentially from the first side to the second side. The illumination device is used to emit light toward the second side, the adjustment mirror group is used to adjust the optical path of the light and project it toward the reflector, and the reflector is used to reflect the light toward the first side for projection onto the first side. The adjusting lens group includes a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially from the first side to the second side; the second lens group, the third lens group, and the fourth lens group are movably arranged along the optical axis direction, the optical power of the first lens group and the second lens group is positive, and the optical power of the third lens group and the fourth lens group is negative; The projection ratio of the optical projection system is less than or equal to 0.18, the aperture number F of the optical projection system is F≥2.2, and the luminous flux of the optical projection system is greater than or equal to 4000lm.

[0016] The technical solution of this invention breaks through the performance bottlenecks of existing ultra-short throw projectors in terms of projection ratio, brightness, and aperture number by using the positive and negative combination of the optical power of the lens group and the movable design of the lens group, and achieves the technical effect of simultaneously satisfying low projection ratio, large aperture, and high light flux. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of an embodiment of the optical projection system provided by the present invention; Figure 2 for Figure 1 A schematic diagram of the MTF curve of a medium-wave optical projection system; Figure 3 for Figure 1 A schematic diagram of the vertical chromatic aberration curve of a medium optical projection system; Figure 4 for Figure 1 A schematic diagram of the SPOT point in a medium-light optical projection system.

[0019] Explanation of icon numbers: 100. Optical projection system; 1. Illumination device; 2. Adjustment lens group; 21. First lens group; 211. First lens; 212. Second lens; 213. Third lens; 214. Fourth lens; 215. Fifth lens; 216. Sixth lens; 217. Seventh lens; 218. Eighth lens; 219. Ninth lens; 2110. Tenth lens; 2111. Eleventh lens; 2112. Twelfth lens; 2113. Aperture stop; 22. Second lens group; 221. Thirteenth lens; 23. Third lens group; 231. Fourteenth lens; 232. Fifteenth lens; 233. Sixteenth lens; 24. Fourth lens group; 241. Seventeenth lens; 3. Reflector.

[0020] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0024] Most ultra-short throw projectors on the market have a throw ratio of 0.22 or higher, with only a few having a throw ratio of 0.2. They also tend to have low brightness, generally below 2000lm, and cannot simultaneously meet the requirements of high brightness, large aperture, and low transmittance.

[0025] This invention proposes an optical projection system.

[0026] Please see Figure 1 In one embodiment of the present invention, the optical projection system 100 has a first side and a second side arranged opposite to each other along the optical axis. The optical projection system 100 includes an illumination device 1, an adjustment mirror group 2, and a reflector 3 arranged sequentially from the first side to the second side. The illumination device 1 is used to emit light toward the second side, the adjustment mirror group 2 is used to adjust the optical path of the light and emit it toward the reflector 3, and the reflector 3 is used to reflect the light toward the first side for projection onto the first side. The adjusting lens group 2 includes a first lens group 21, a second lens group 22, a third lens group 23, and a fourth lens group 24 arranged sequentially from the first side to the second side; the second lens group 22, the third lens group 23, and the fourth lens group 24 are movably arranged along the optical axis, the optical power of the first lens group 21 and the second lens group 22 is positive, and the optical power of the third lens group 23 and the fourth lens group 24 is negative; The projection ratio of the optical projection system 100 is less than or equal to 0.18, the aperture number F of the optical projection system 100 is F≥2.2, and the luminous flux of the optical projection system 100 is greater than or equal to 4000lm.

[0027] In the technical solution of this invention, the first and second lens groups with positive optical power have the core function of focusing and collimating light, converging the divergent light emitted from the illumination device 1 to improve the utilization rate of light and provide core focusing support for achieving a high luminous flux of ≥4000lm. At the same time, they initially compress the optical path to adapt to the field of view requirements of ultra-short distance projection. The third and fourth lens groups with negative optical power have the core function of expanding the beam and correcting aberrations. On the basis of focusing, they expand the beam of light to a wide angle, improve the field of view (correspondingly reducing the projection ratio), and correct aberrations such as distortion and chromatic aberration caused by the positive optical power lens groups to ensure the clarity of the projected image and avoid image distortion under ultra-low projection ratio. The second, third, and fourth lens groups are set movably along the optical axis. By finely adjusting the axial spacing between the lens groups, dynamic calibration of the optical path parameters can be achieved. This can not only adapt to the field of view requirements of different projected image sizes, but also compensate for the optical path offset caused by temperature and assembly errors. At the same time, it ensures the stability of the aperture number and luminous flux during the adjustment process, solving the problem that fixed lens groups cannot take into account multiple performance indicators. Existing ultra-short-throw projectors often employ non-gradient optical power combinations, which can lead to a contradiction: insufficient field of view (high throw ratio) when focusing the light, and light flux loss (low brightness) when expanding the beam. This solution designs four lens groups with a positive-positive-negative-negative gradient optical power. The first two positive optical power lens groups achieve efficient light focusing to ensure brightness, while the latter two negative optical power lens groups achieve wide-angle beam expansion, thereby reducing the throw ratio. Furthermore, the optical power of the front and rear lens groups is complementary, effectively canceling out their aberrations. This achieves a low throw ratio of ≤0.18 while avoiding excessive light flux loss and providing optical architecture support for a high light flux of over 4000lm. Additionally, by reflecting the light path through mirror 3, the distance between the projector and the projection surface is significantly reduced, which is beneficial for achieving a low transmittance.

[0028] To achieve a 100% gain in the optical projection system, the focal lengths of each lens group need to be designed: the focal length of the first lens group 21 is F1, 20mm≤F1≤30mm; the focal length of the first lens group 21 is F2, 70mm≤F2≤90mm; the focal length of the first lens group 21 is F3, -50mm≤F3≤-30mm; and the focal length of the first lens group 21 is F4, -70mm≤F4≤-50mm. By increasing the focal length of the lens groups with positive optical power, efficient light focusing and brightness are maintained first; then, by decreasing the focal length of the lens groups with negative optical power, wide-angle beam expansion and reduced projection ratio are achieved.

[0029] For each lens, specifically: the first lens group 21 includes the following lenses arranged sequentially from the first side to the second side: first lens 211, second lens 212, third lens 213, fourth lens 214, fifth lens 215, sixth lens 216, seventh lens 217, eighth lens 218, ninth lens 219, tenth lens 2110, eleventh lens 2111, and twelfth lens 2112; the focal length of the first lens 211 is f1, 25≤f1≤35; the focal length of the second lens 211 is... The focal length of the first lens 212 is f2, 25≤f2≤40; the focal length of the third lens 213 is f3, 35≤f3≤45; the focal length of the fourth lens 214 is f4, -15≤f4≤-5; the focal length of the fifth lens 215 is f5, 30≤f5≤40; the focal length of the sixth lens 216 is f6, 15≤f6≤30; the focal length of the seventh lens 217 is f7, -15≤f7≤-5; the focal length of the eighth lens 218 is f8, 5≤f8≤20; the ninth lens... The focal length of lens 219 is f9, 5≤f9≤20; the focal length of the tenth lens 2110 is f10, -35≤f10≤-20; the focal length of the eleventh lens 2111 is f11, -20≤f11≤-10; the focal length of the twelfth lens 2112 is f12, 50≤f12≤70; the second lens group 22 includes a thirteenth lens 221, the focal length of which is f13, 70≤f13≤90; the third lens group 23 includes lenses extending from the first side to the... The following lenses are arranged sequentially on the second side: the fourteenth lens 231, the fifteenth lens 232, and the sixteenth lens 233; the focal length of the fourteenth lens 231 is f14, 50≤f14≤70; the focal length of the fifteenth lens 232 is f15, -45≤f15≤-30; the focal length of the sixteenth lens 233 is f16, -50≤f16≤-30; the fourth lens group 24 includes the seventeenth lens 241, the focal length of the seventeenth lens 241 is f17, -70≤f17≤-50.

[0030] Aspherical lenses are far more difficult and costly to manufacture than spherical lenses. They are only used at core aberration nodes and critical optical path functional nodes where spherical lenses cannot solve the problem, avoiding the excessively high mass production costs and assembly difficulties caused by a fully aspherical design. Therefore, the second lens 212, the thirteenth lens 221, the sixteenth lens 233, and the seventeenth lens 241 are aspherical lenses. The first lens 211, the third lens 213, the fourth lens 214, the fifth lens 215, the sixth lens 216, the seventh lens 217, the eighth lens 218, the ninth lens 219, the tenth lens 2110, the eleventh lens 2111, the twelfth lens 2112, the fourteenth lens 231, and the fifteenth lens 232 are spherical lenses.

[0031] Four aspherical lenses are strategically positioned in key locations within the first lens group 21, the second lens group 22, the third lens group 23, and the fourth lens group 24. Their aspherical characteristics directly compensate for the shortcomings of spherical lenses, while simultaneously enhancing the functionality of the corresponding lens groups. The second lens 212 is used for primary light focusing, spherical aberration correction, and improved light uniformity. The thirteenth lens 221, through its curved surface design, reduces spherical aberration and precisely collimates the light, ensuring that the light rays are incident parallel to the third lens group 23, providing the most stable incident light for subsequent beam expansion and maximizing beam expansion efficiency. The sixteenth lens 233 precisely corrects the beam expansion distortion and spherical aberration of the fifteenth lens 232, ensuring a uniform distribution of the expanded light angle and guaranteeing consistent edge and center sharpness in the projected image. The seventeenth lens 241 serves as the final aberration correction throughout the entire optical path, adapting to the optical path reflection of the third reflector.

[0032] In one embodiment, the first lens 211, the second lens 212, the third lens 213, the fourth lens 214, the fifth lens 215, the sixth lens 216, the seventh lens 217, the eighth lens 218, the ninth lens 219, the tenth lens 2110, the eleventh lens 2111, the twelfth lens 2112, the thirteenth lens 221, the fourteenth lens 231, and the fifteenth lens 232 are glass lenses; the sixteenth lens 233 and the seventeenth lens 241 are plastic lenses. The sixteenth lens 233 and the seventeenth lens 241, as the only two plastic aspherical lenses, utilize the advantages of injection molding of plastic aspherical surfaces to achieve high-precision wide-angle adaptation, lightweight design, and low cost, which are difficult to achieve with glass lenses. Simultaneously, they perfectly inherit the optical path output of the front and middle section glass lenses, completing the three core tasks of final beam expansion, final aberration correction, and reflected light path adaptation.

[0033] In one embodiment, the third lens 213, the fourth lens 214, and the fifth lens 215 are cemented together; the sixth lens 216, the seventh lens 217, and the eighth lens 218 are cemented together; and the ninth lens 219 and the tenth lens 2110 are cemented together. Cemented triplet lenses and cemented doublet lenses are primarily used to correct axial chromatic aberration and transverse chromatic aberration.

[0034] Combining previous focal length parameters, spherical nonlinear properties, glass-plastic materials, and cemented structure design, by precisely defining the Abbe number (dispersion coefficient) range for each lens, lenses with different dispersion characteristics can form complementary and synergistic dispersion in the optical path. This improves the three core dispersion problems of ultra-short-throw projection caused by large field of view, strong light focusing, and wide-angle beam expansion: positional chromatic aberration, magnification chromatic aberration, and color distortion. This further enhances image color reproduction and edge color consistency. Specifically: the Abbe number of the first lens 211 is V1, 15.0 ≤ v1 ≤ 30.0; the Abbe number of the second lens 212 is V2, 70.0 ≤ v2 ≤ 95.0; the Abbe number of the third lens 213 is V3, 70.0 ≤ v3 ≤ 95.0; the Abbe number of the fourth lens 214 is V4, 15.0 ≤ v4 ≤ 30.0; the Abbe number of the fifth lens 215 is V5, 60.0 ≤ v5 ≤ 90.0; the Abbe number of the sixth lens 216 is V6, 60.0 ≤ v6 ≤ 90.0; the Abbe number of the seventh lens 217 is V7, 20.0 ≤ v7 ≤ 35.0; the Abbe number of the eighth lens 218 is V8, 45.0 ≤ v8 ≤ 75.0; and the Abbe number of the ninth lens 219 is V9, 20.0 ≤ v9 ≤ 4. 5.0; the Abbe number of the tenth lens 2110 is V10, 20.0≤v10≤50.0; the Abbe number of the eleventh lens 2111 is V11, 30.0≤v11≤50.0; the Abbe number of the twelfth lens 2112 is V12, 30.0≤v12≤50.0; the Abbe number of the thirteenth lens 221 is V13, 30.0≤v13≤50.0 0; the Abbe number of the fourteenth lens 231 is V14, 75.0≤v14≤95.0; the Abbe number of the fifteenth lens 232 is V15, 20.0≤v15≤35.0; the Abbe number of the sixteenth lens 233 is V16, 50.0≤v16≤65.0; the Abbe number of the seventeenth lens 241 is V17, 50.0≤v17≤65.0.

[0035] By precisely defining the refractive index range of each lens, the light deflection angle of lenses with different refractive properties can be precisely controlled in the optical path, fundamentally improving the problems of uneven optical path difference, uncontrolled light deflection, and mismatch between materials and optical parameters caused by large field of view, strong light focusing, wide-angle beam expansion, and optical path reflection in short-throw projection. Specifically: the refractive index of the first lens 211 is N1, 1.80≤n1≤2.00; the refractive index of the second lens 212 is N2, 1.45≤n2≤1.65; the refractive index of the third lens 213 is N3, 1.45≤n3≤1.65; the refractive index of the fourth lens 214 is N4, 1.85≤n4≤2.10; the refractive index of the fifth lens 215 is N5, 1.45≤n5≤1.65; the refractive index of the sixth lens 216 is N6, 1.45≤n6≤1.65; the refractive index of the seventh lens 217 is N7, 1.80≤n7≤1.95; the refractive index of the eighth lens 218 is N8, 1.45≤n8≤1.60; and the refractive index of the ninth lens 219 is N9, 1.55≤n9≤1. The refractive index of the tenth lens 2110 is N10, 1.70≤n10≤1.90; the refractive index of the eleventh lens 2111 is N11, 1.60≤n11≤1.85; the refractive index of the twelfth lens 2112 is N12, 1.60≤n12≤1.85; the refractive index of the thirteenth lens 221 is N13, 1.55≤n13≤1.80; the refractive index of the fourteenth lens 231 is N14, 1.45≤n14≤1.60; the refractive index of the fifteenth lens 232 is N15, 1.75≤n15≤1.95; the refractive index of the sixteenth lens 233 is N16, 1.45≤n16≤1.60; and the refractive index of the seventeenth lens 241 is N17, 1.45≤n17≤1.60.

[0036] The first lens group 21 further includes an aperture stop 2113, which is positioned between the eighth lens 218 and the ninth lens 219. At this location, the aperture stop 2113 enables full-range light control, including stray light filtering, energy distribution, and optical axis calibration. It becomes a core component for efficient utilization of light energy and improved image quality across the entire optical path, solving the problems of stray light interference, uneven energy distribution, and optical axis misalignment caused by strong light focusing and wide-angle beam expansion in short-throw projection. Based on the above design, the total optical length of the optical projection system 100 is TTL, with TTL ≤ 175.5 mm, and the TV distortion of the optical projection system 100 is less than or equal to 0.2%. This allows for miniaturization of the optical projection system 100 and provides good distortion suppression.

[0037] In one specific embodiment: the optical projection system has a focal length f = 1.78, an aperture value F = 2.2, and a luminous surface diameter of 18 mm. Specific parameters are shown in the table below: Table 1:

[0038] The second lens 212, the thirteenth lens 221, the sixteenth lens 233, and the seventeenth lens 241 are aspherical lenses, and the surface shapes of the aspherical mirrors satisfy the equation:

[0039] In the above equation, parameter c is the curvature corresponding to the radius, y is the radial coordinate with the same unit as the lens length, and k is the conic conic coefficient. When the coefficient k is less than -1, the surface curve of the lens is a hyperbola; when the coefficient k is equal to -1, the surface curve of the lens is a parabola; when the coefficient k is between -1 and 0, the surface curve of the lens is an ellipse; when the coefficient k is equal to 0, the surface curve of the lens is a circle; and when the coefficient k is greater than 0, the surface curve of the lens is an oval. α1 to α8 represent the coefficients corresponding to each radial coordinate.

[0040] Table 2:

[0041] For simulation results of this implementation, please refer to [link / reference]. Figures 2 to 4 .

[0042] The present invention also proposes a projector, which includes an optical projection system 100. The specific structure of the optical projection system 100 is as described in the above embodiments. Since this projector adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here. The optical projection system 100 has a first side and a second side arranged opposite to each other along the optical axis. The optical projection system 100 includes an illumination device 1, an adjustment mirror group 2, and a reflector 3 arranged sequentially from the first side to the second side. The illumination device 1 is used to emit light toward the second side, the adjustment mirror group 2 is used to adjust the optical path of the light and project it toward the reflector 3, and the reflector 3 is used to reflect the light toward the first side for projection onto the first side. The adjusting lens group 2 includes a first lens group 21, a second lens group 22, a third lens group 23, and a fourth lens group 24 arranged sequentially from the first side to the second side; the second lens group 22, the third lens group 23, and the fourth lens group 24 are movably arranged along the optical axis, the optical power of the first lens group 21 and the second lens group 22 is positive, and the optical power of the third lens group 23 and the fourth lens group 24 is negative; The projection ratio of the optical projection system 100 is less than or equal to 0.18, the aperture number F of the optical projection system 100 is F≥2.2, and the luminous flux of the optical projection system 100 is greater than or equal to 4000lm.

[0043] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An optical projection system, characterized in that, The optical projection system has a first side and a second side arranged opposite to each other along the optical axis. The optical projection system includes an illumination device, an adjustment mirror group, and a reflector arranged sequentially from the first side to the second side. The illumination device is used to emit light towards the second side, the adjustment mirror group is used to adjust the optical path of the light and emit it towards the reflector, and the reflector is used to reflect the light towards the first side for projection onto the first side. The adjustment lens group includes a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially from the first side to the second side; The second lens group, the third lens group, and the fourth lens group are movably arranged along the optical axis direction. The optical power of the first lens group and the second lens group is positive, and the optical power of the third lens group and the fourth lens group is negative. The projection ratio of the optical projection system is less than or equal to 0.18, the aperture number F of the optical projection system is F≥2.2, and the luminous flux of the optical projection system is greater than or equal to 4000lm.

2. The optical projection system as described in claim 1, characterized in that, The focal length of the first lens group is F1, 20mm≤F1≤30mm; The focal length of the first lens group is F2, 70mm≤F2≤90mm; The focal length of the first lens group is F3, -50mm≤F3≤-30mm; The focal length of the first lens group is F4, -70mm≤F4≤-50mm.

3. The optical projection system as described in claim 2, characterized in that, The first lens group comprises, sequentially arranged from the first side to the second side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens; the focal length of the first lens is f1, 25≤f1≤35; the focal length of the second lens is f2, 25≤f2≤40; the focal length of the third lens is f3, 35≤f3≤45; the focal length of the fourth lens is f4, -15≤f4≤-5; the fifth lens... The focal length of the first lens is f5, 30≤f5≤40; the focal length of the sixth lens is f6, 15≤f6≤30; the focal length of the seventh lens is f7, -15≤f7≤-5; the focal length of the eighth lens is f8, 5≤f8≤20; the focal length of the ninth lens is f9, 5≤f9≤20; the focal length of the tenth lens is f10, -35≤f10≤-20; the focal length of the eleventh lens is f11, -20≤f11≤-10; and the focal length of the twelfth lens is f12, 50≤f12≤70. The second lens group includes a thirteenth lens, the focal length of which is f13, and 70≤f13≤90; The third lens group includes a fourteenth lens, a fifteenth lens, and a sixteenth lens arranged sequentially from the first side to the second side; the fourteenth lens has a focal length of f14, 50≤f14≤70; the fifteenth lens has a focal length of f15, -45≤f15≤-30; and the sixteenth lens has a focal length of f16, -50≤f16≤-30. The fourth lens group includes a seventeenth lens, the seventeenth lens having a focal length of f17, -70≤f17≤-50.

4. The optical projection system as described in claim 3, characterized in that, The first lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the fourteenth lens, and the fifteenth lens are spherical lenses; The second lens, the thirteenth lens, the sixteenth lens, and the seventeenth lens are aspherical lenses.

5. The optical projection system as described in claim 3, characterized in that, The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, the fourteenth lens, and the fifteenth lens are glass lenses; The sixteenth lens and the seventeenth lens are plastic lenses.

6. The optical projection system as described in claim 3, characterized in that, The third, fourth, and fifth lenses are cemented together; the sixth, seventh, and eighth lenses are cemented together; and the ninth and tenth lenses are cemented together.

7. The optical projection system as described in claim 3, characterized in that, The Abbe number of the first lens is V1, where 15.0 ≤ v1 ≤ 30.0; The Abbe number of the second lens is V2, where 70.0 ≤ v2 ≤ 95.0; The Abbe number of the third lens is V3, where 70.0 ≤ v3 ≤ 95.0; The Abbe number of the fourth lens is V4, where 15.0 ≤ v4 ≤ 30.0; The Abbe number of the fifth lens is V5, where 60.0 ≤ v5 ≤ 90.0; The Abbe number of the sixth lens is V6, where 60.0 ≤ v6 ≤ 90.0; The Abbe number of the seventh lens is V7, where 20.0 ≤ v7 ≤ 35.0; The Abbe number of the eighth lens is V8, where 45.0 ≤ v8 ≤ 75.0; The Abbe number of the ninth lens is V9, where 20.0 ≤ v9 ≤ 45.0; The Abbe number of the tenth lens is V10, where 20.0 ≤ v10 ≤ 50.0; The Abbe number of the eleventh lens is V11, where 30.0 ≤ v11 ≤ 50.0; The Abbe number of the twelfth lens is V12, where 30.0 ≤ v12 ≤ 50.0; The Abbe number of the thirteenth lens is V13, where 30.0 ≤ v13 ≤ 50.0; The Abbe number of the fourteenth lens is V14, where 75.0 ≤ v14 ≤ 95.0; The Abbe number of the fifteenth lens is V15, where 20.0 ≤ v15 ≤ 35.0; The Abbe number of the sixteenth lens is V16, where 50.0 ≤ v16 ≤ 65.0; The Abbe number of the seventeenth lens is V17, where 50.0 ≤ v17 ≤ 65.

0.

8. The optical projection system as described in claim 3, characterized in that, The refractive index of the first lens is N1, where 1.80 ≤ n1 ≤ 2.00; The refractive index of the second lens is N2, where 1.45 ≤ n2 ≤ 1.65; The refractive index of the third lens is N3, where 1.45 ≤ n3 ≤ 1.65; The refractive index of the fourth lens is N4, where 1.85 ≤ n4 ≤ 2.10; The refractive index of the fifth lens is N5, where 1.45 ≤ n5 ≤ 1.65; The refractive index of the sixth lens is N6, where 1.45 ≤ n6 ≤ 1.65; The refractive index of the seventh lens is N7, where 1.80 ≤ n7 ≤ 1.95; The refractive index of the eighth lens is N8, where 1.45 ≤ n8 ≤ 1.60; The refractive index of the ninth lens is N9, where 1.55 ≤ n9 ≤ 1.85; The refractive index of the tenth lens is N10, where 1.70 ≤ n10 ≤ 1.90; The refractive index of the eleventh lens is N11, where 1.60 ≤ n11 ≤ 1.85; The refractive index of the twelfth lens is N12, 1.60≤n12≤1.85; The refractive index of the thirteenth lens is N13, where 1.55 ≤ n13 ≤ 1.80; The refractive index of the fourteenth lens is N14, where 1.45 ≤ n14 ≤ 1.60; The refractive index of the fifteenth lens is N15, where 1.75 ≤ n15 ≤ 1.95; The refractive index of the sixteenth lens is N16, where 1.45 ≤ n16 ≤ 1.60; The refractive index of the seventeenth lens is N17, where 1.45 ≤ n17 ≤ 1.

60.

9. The optical projection system as described in claim 3, characterized in that, The first lens group further includes an aperture stop, which is disposed between the eighth lens and the ninth lens; the total optical length of the optical projection system is TTL, TTL≤175.5mm, and the TV distortion of the optical projection system is less than or equal to 0.2%.

10. A projector, characterized in that, Includes the optical projection system as described in any one of claims 1 to 9.

Images