Projection lens and laser projection device

Abstract

The present application discloses a projection lens and a laser projection device, belonging to the field of laser technology. The projection lens includes a rear lens group, a third movable lens group, a second movable lens group, a first movable lens group, and a front lens group sequentially arranged along the optical path direction of the projection lens; the rear lens group receives the light emitted by the light valve assembly, corrects and collimates the light, and then guides it to the third movable lens group; the third movable lens group, the second movable lens group, and the first movable lens group move along the optical axis direction of the projection lens. The third movable lens group compensates for the received light and guides it to the second movable lens group. The second movable lens group changes the angle at which the light enters the first movable lens group. The first movable lens group guides the received light to the front lens group and adjusts the size of the image output by the projection lens to the projection screen; the front lens group compensates for the received light and guides the light to the projection screen. This solves the problem of the incomplete performance of the projection lens in the related art and achieves the effect of improving the comprehensiveness of the performance of the projection lens.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and particularly relates to a projection lens and a laser projection device. Background Art

[0002] Currently, engineering projection devices are mostly used in large conferences and other places. Engineering projection devices have high brightness and can project large-sized images. The lenses of engineering projection devices are mostly long-focus zoom lenses. The higher the zoom ratio of the lens, the more lenses it uses, resulting in a larger volume of the lens.

[0003] In related technologies, projection devices with high lumen density (HLD) light sources or light-emitting diode (LED) projection devices are mostly used. Since the HLD light source has all three primary colors at the same time, it can achieve a wider color gamut coverage. However, the HLD light source has poor brightness, and increasing the brightness will cause the volume of the projection device to increase, making it inconvenient to use. With the continuous expansion of the application range of engineering projection devices, the requirements for the resolution of engineering projection devices are also getting higher and higher. LED projection devices usually can reach a resolution of 720P or 1080P and cannot achieve higher resolutions.

[0004] The above-mentioned projection devices cannot achieve both high resolution and small volume, and their performance is not comprehensive. Summary of the Invention

[0005] Embodiments of the present application provide a projection lens and a laser projection device, and the technical solutions are as follows:

[0006] On the one hand, a projection lens is provided. The projection lens includes a rear lens group, a third moving lens group, a second moving lens group, a first moving lens group, and a front lens group that are sequentially arranged along the optical path direction of the projection lens;

[0007] The rear lens group is configured to receive light rays emitted by a light valve assembly, and after correcting and collimating the light rays, direct them to the third moving lens group;

[0008] The third moving lens group, the second moving lens group, and the first moving lens group can move along the optical axis direction of the projection lens. The third moving lens group compensates the received light rays and directs them to the second moving lens group. The second moving lens group is configured to change the angle of the light rays incident on the first moving lens group. The first moving lens group directs the received light rays to the front lens group and is configured to adjust the size of the image output by the projection lens to a projection screen;

[0009] The front lens group is configured to compensate the received light rays and direct the light rays to the projection screen.

[0010] Optionally, the front lens group includes a first lens, a second lens, and a third lens sequentially arranged in the reverse direction of the optical path direction of the projection lens;

[0011] The first lens and the second lens are bonded to provide an orthodontic variable. The refractive index of the first lens is greater than that of the second lens, and the Abbe number of the first lens is less than that of the second lens;

[0012] The curvature of the surface of the third lens close to the second lens is less than the curvature of the surface of the third lens far from the second lens. The third lens is used to correct the direction of the light and provide a negative distortion variable.

[0013] Optionally, the first moving lens group includes a fourth lens, a fifth lens, and a sixth lens sequentially arranged in the reverse direction of the optical path direction of the projection lens;

[0014] The fourth lens is a convex-concave positive lens, the fifth lens is a convex-concave positive spherical lens, and the sixth lens is a biconcave negative spherical lens;

[0015] The convex surfaces of the fourth lens and the fifth lens both face the front lens group, and the more concave surface of the two concave surfaces of the sixth lens faces the concave surface of the fifth lens;

[0016] The fifth lens and the sixth lens provide an orthodontic variable, and the fourth lens provides a negative distortion variable.

[0017] Optionally, the second moving lens group includes a seventh lens and an eighth lens sequentially arranged in the reverse direction of the optical path direction of the projection lens;

[0018] The seventh lens is a positive lens, the eighth lens is a negative lens, and the seventh lens and the eighth lens cooperate to correct the spherical aberration and coma of the light.

[0019] Optionally, the third moving lens group includes a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, a fifteenth lens, and a sixteenth lens sequentially arranged in the reverse direction of the optical path direction of the projection lens;

[0020] The tenth lens and the eleventh lens are bonded, the twelfth lens and the thirteenth lens are bonded, and the fourteenth lens and the fifteenth lens are bonded to correct the lateral chromatic aberration and axial chromatic aberration of the light;

[0021] The sixteenth lens is used to converge the light;

[0022] The projection lens further includes an aperture stop, and the aperture stop is located between the ninth lens and the tenth lens;

[0023] The rear lens group includes a seventeenth lens sequentially arranged in the reverse direction of the optical path direction of the projection lens.

[0024] Optionally, the first lens is a convex-concave positive lens, the second lens is a biconvex positive lens, the third lens is a convex-concave positive lens, the seventh lens is a biconcave negative lens, the eighth lens is a biconvex positive lens, the ninth lens is a biconvex positive spherical lens, the tenth lens is a biconvex positive spherical lens, the eleventh lens is a convex-concave positive lens, the twelfth lens is a biconcave negative lens, the thirteenth lens is a biconvex positive lens, the fourteenth lens is a biconcave negative lens, the fifteenth lens is a biconvex positive lens, the sixteenth lens is a biconvex positive lens, and the seventeenth lens is a convex-concave positive lens.

[0025] Optionally, the total length of the projection lens is L0, the length of the front lens group is L1, the length of the first moving lens group is L2, the length of the second moving lens group is L3, the length of the third moving lens group is L4, and the length of the rear lens group is L5;

[0026] L1 satisfies the formula 0.1 < |L1 / L0| < 0.2;

[0027] L2 satisfies the formula 0.15 < |L2 / L0| < 0.25;

[0028] L3 satisfies the formula 0.2 < |L3 / L0| < 0.3;

[0029] L4 satisfies the formula 0.26 < |L4 / L0| < 0.42;

[0030] L5 satisfies the formula 0.01 < |L5 / L0| < 0.1.

[0031] Optionally, the effective focal length of the front lens group is F1, the effective focal length of the first moving lens group is F2, the effective focal length of the second moving lens group is F3, the effective focal length of the third moving lens group is F4, and the effective focal length of the rear lens group is F5;

[0032] F1 satisfies the formula 2.0 < |F1 / F0| < 6.0;

[0033] F2 satisfies the formula 0.2 < |F2 / F0| < 1.0;

[0034] F3 satisfies the formula 2.8 < |F3 / F0| < 7.2;

[0035] F4 satisfies the formula 1.1 < |F4 / F0| < 4.2;

[0036] F5 satisfies the formula 1.8 < |F5 / F0| < 5.3;

[0037] Wherein, F0 is the effective focal length of the projection lens.

[0038] On the other hand, a laser projection device is provided, including the projection lens described in the first aspect.

[0039] Optionally, the laser projection device further includes a light valve assembly, and the light valve assembly includes a light valve and a galvanometer scanner. The galvanometer scanner deflects the light emitted from the light valve and then guides it to the projection lens.

[0040] The beneficial effects brought by the technical solutions provided in the embodiments of the present application are:

[0041] A projection lens is provided, which includes a rear lens group, a third moving lens group, a second moving lens group, a first moving lens group, and a front lens group that are sequentially arranged along the optical path direction of the projection lens. The rear lens group guides the light emitted from the light valve assembly to the third moving lens group, the third moving lens group guides the received light to the second moving lens group, the second moving lens group guides the received light to the first moving lens group, the first moving lens group guides the received light to the front lens group, and the front lens group compensates the light and then guides it to the projection screen. This projection lens can be applied to a laser light source, wherein the third moving lens group compensates the received light, the second moving lens group can change the angle of the light incident on the first moving lens group, the first moving lens group can adjust the size of the image projected onto the projection screen by moving along the optical axis direction of the projection lens, and the rear lens group and the front lens group can compensate the light by moving to make the final image clearer. The entire projection lens has a simple structure and can achieve high resolution and high-definition imaging while having a small volume. It solves the problem of incomplete performance of the projection lens in the related art and achieves the effect of improving the comprehensiveness of the projection lens performance. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0043] Figure 1 It is a schematic diagram of the implementation environment related to the embodiments of the present application;

[0044] Figure 2 It is a schematic structural diagram of a projection lens provided by the embodiments of the present application;

[0045] Figure 3 It is a schematic structural diagram of another projection lens provided by the embodiments of the present application;

[0046] Figure 4 Schematic structural diagram of another projection lens provided by an embodiment of the present application;

[0047] Figure 5 Schematic structural diagram of another projection lens provided by an embodiment of the present application;

[0048] Figure 6 Schematic structural diagram of the light beam in the projection lens provided by an embodiment of the present application transmitted to the projection screen;

[0049] Figure 7 Schematic structural diagram of a laser projection device provided by an embodiment of the present application.

[0050] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and text descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Specific Embodiments

[0051] To make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0052] Since the use sites of engineering projection devices are mostly large sites, engineering projection devices generally have requirements for high brightness and the ability to project large-sized images. With the expansion of the use scope and the change of the use environment of engineering projection devices, such as indoor sites for large conferences, the resolution requirements for engineering projection devices are also gradually increasing. In related technologies, HLD light source projection devices are usually used, which will increase the volume of the HLD light source projection devices while improving the brightness, resulting in a decrease in the flexibility of use of the HLD light source projection devices. LED projection devices are smaller in volume and have higher flexibility in use, but the resolution of LED projection devices is mostly 720P or 1080P, and it has gradually been unable to meet the high-resolution requirements for engineering projection devices. That is to say, the engineering projection devices in related technologies cannot have a small volume while having high resolution and high brightness, resulting in incomplete performance of the engineering projection devices.

[0053] The embodiments of the present application provide a projection lens and a laser projection device, which can solve the problems in the above-mentioned related technologies.

[0054] Figure 1 It is a schematic diagram of the implementation environment involved in the embodiments of the present application. The implementation environment may include a laser projection device 10 and a projection screen 20.

[0055] The laser projection device 10 may include an illumination device 11 and a projection lens 12. The illumination device 11 is used to provide a light source to the projection lens 12, and the projection lens 12 is used to project a preset pattern onto a projection screen 20 according to the light source provided by the illumination device 11.

[0056] The projection screen 20 is used to carry the pattern projected by the projection lens 12. The projection screen 20 may be made of various materials, such as polyvinyl chloride (PVC), metal, fiberglass, and glass beads, etc., and the embodiments of the present application do not make any restrictions.

[0057] Figure 2 It is a schematic structural diagram of a projection lens provided by an embodiment of the present application. The structure of the projection lens 30 is as follows:

[0058] The projection lens 30 includes a rear lens group 31, a third moving lens group 32, a second moving lens group 33, a first moving lens group 34, and a front lens group 35 that are sequentially arranged along the optical path direction 40 of the projection lens.

[0059] The rear lens group 31 is used to receive the light emitted by the light valve assembly 50, and guide the light to the third moving lens group 32 after correcting and collimating the light.

[0060] The third moving lens group 32, the second moving lens group 33, and the first moving lens group 34 can move along the optical axis direction of the projection lens 30. The third moving lens group 32 compensates the received light and guides it to the second moving lens group 33. The second moving lens group 33 is used to change the angle of the light incident on the first moving lens group 34. The first moving lens group 34 guides the received light to the front lens group 35 and is used to adjust the size of the image output by the projection lens 30 to the projection screen 20.

[0061] The front lens group 35 is used to compensate the received light and guide the light to the projection screen 20.

[0062] In summary, the embodiment of the present application provides a projection lens including a rear lens group, a third moving lens group, a second moving lens group, a first moving lens group, and a front lens group arranged in sequence along the optical path direction of the projection lens. The rear lens group guides the light emitted from the light valve assembly to the third moving lens group. The third moving lens group guides the received light to the second moving lens group. The second moving lens group guides the received light to the first moving lens group. The first moving lens group guides the received light to the front lens group. The front lens group compensates the light and then guides it to the projection screen. This projection lens can be applied to a laser light source, wherein the third moving lens group compensates the received light, the second moving lens group can change the angle of the light incident on the first moving lens group, the first moving lens group can adjust the size of the image projected by the projection lens onto the projection screen by moving along the optical axis direction of the projection lens, and the rear lens group and the front lens group can compensate the light by moving to make the final image clearer. The entire projection lens has a simple structure and can achieve high resolution and high-definition imaging while having a small volume. It solves the problem of incomplete performance of the projection lens in the related art and achieves the effect of improving the comprehensiveness of the projection lens performance.

[0063] As Figure 3 shown, it is a schematic structural diagram of another projection lens 30 provided by the embodiment of the present application.

[0064] Optionally, the front lens group 35 includes a first lens 351, a second lens 352, and a third lens 353 arranged in sequence in the reverse direction of the optical path direction 40 of the projection lens; the first lens 351 and the second lens 352 are bonded to provide an orthoscopic variable. The refractive index of the first lens 351 is greater than that of the second lens 352, and the Abbe number of the first lens 351 is less than that of the second lens 352; the curvature of the surface of the third lens 353 close to the second lens 352 is less than the curvature of the surface of the third lens 353 away from the second lens 352. The third lens 353 is used to correct the direction of light and provide a negative distortion variable. The front lens group 35 is close to the projection screen 20 and is used to compensate for the light emitted from the first moving lens group 34 and direct the light to the projection screen 20. The compensation for light includes improving the astigmatism, coma, and distortion of the light. Distortion is one of the aberrations that characterize the imaging distortion of an optical system. In the front lens group 35, the orthoscopic variable provided by the bonded first lens 351 and second lens 352 and the negative distortion variable provided by the third lens 353 act together to correct the final imaging effect. Astigmatism and coma are forms of light spots generated during the imaging process of the light beam and affect the clarity of the imaging result. For specific research on astigmatism and coma, reference can be made to related technologies, and the embodiments of the present application will not elaborate here. The Abbe number is an index used to represent the dispersion ability of a transparent medium. Generally, the greater the refractive index, the more severe the dispersion, and the smaller the Abbe number; conversely, the smaller the refractive index, the milder the dispersion, and the greater the Abbe number. In the embodiments of the present application, the refractive index of the first lens 351 is greater than that of the second lens 352, so the Abbe number of the first lens 351 is less than that of the second lens 352. The bonding method of the first lens 351 and the second lens 352 can be gluing or other methods, which are not limited in the embodiments of the present application.

[0065] Optionally, the first moving lens group 34 includes a fourth lens 341, a fifth lens 342, and a sixth lens 343 arranged in sequence in the reverse direction of the optical path direction 40 of the projection lens; the fourth lens 341 is a convex-concave positive lens, the fifth lens 342 is a convex-concave positive spherical lens, and the sixth lens 343 is a biconcave negative spherical lens; the convex surfaces of the fourth lens 341 and the fifth lens 342 face the front lens group, and the more concave surface of the two concave surfaces of the sixth lens 343 faces the concave surface of the fifth lens 342; the fifth lens 342 and the sixth lens 343 provide an orthoscopic variable, and the fourth lens 341 provides a negative distortion variable. The first moving lens group 34 can move along the optical axis direction of the projection lens. When moving to different positions of the zoom lens group 33, the angles of the light beams emitted to the front lens group are different, so that the ratio of the length and width of the image output by the front lens group 34 to the projection screen 20 changes, thereby changing the size of the projection image.

[0066] Optionally, the second movable lens group 33 includes a seventh lens 331 and an eighth lens 332 arranged in sequence in the opposite direction of the optical path direction 40 of the projection lens; the seventh lens 331 is a positive lens, the eighth lens 332 is a negative lens, and the seventh lens 331 and the eighth lens 332 cooperate to correct the spherical aberration and coma of light. Both the seventh lens 331 and the eighth lens 332 are spherical lenses, wherein the concave surface of the seventh lens 331 faces the image light valve assembly, and the eighth lens 332 is a drum-shaped lens. Spherical aberration, also known as spherical image aberration, refers to the fact that when a beam of light emitted from an on-axis object point passes through a spherical lens, the light beams in different aperture regions of the lens finally converge at different positions on the optical axis, forming a circular diffuse spot on the image plane. The second movable lens group 33 can move along the optical axis direction of the projection lens to change the angle of the incident light on the first movable lens group 34. That is, when the second movable lens group 33 moves, the distance between the second movable lens group 33 and the first movable lens group 34 changes, and the perpendicular height of the incident light entering the first movable lens group 34 from the second movable lens group 33 to the optical axis changes, that is, the incident angle of the light incident on the first movable lens group 34 changes.

[0067] Figure 4 It is a schematic structural diagram of a projection lens provided by an embodiment of the present application. In the figure, a 2x telephoto zoom lens is taken as an example for the projection lens. When the first movable lens group 34 and the second movable lens group 33 move to one end far from the projection screen within their movable ranges, the field of view of the telephoto zoom lens is the smallest at this time, and the size of the image projected onto the projection screen 20 is the smallest. Figure 5 It is a schematic structural diagram of a projection lens provided by an embodiment of the present application. When the first movable lens group 34 and the second movable lens group 33 move to one end close to the projection screen within their movable ranges, the field of view of the telephoto zoom lens is the largest at this time, and the size of the image projected onto the projection screen 20 is the largest. The first movable lens group 34 and the second movable lens group 33 can also move to other positions within their movable ranges, which will not be elaborated in this embodiment of the present application.

[0068] The first movable lens group 34 and the second movable lens group 33 move together to achieve the zoom function of the projection lens. When the size of the image projected by the projection lens 30 onto the projection screen 20 is changed by the movement of the first movable lens group 34 and the second movable lens group 33, the third movable lens group 32, the front lens group 35, and the rear lens group 31 can correct and compensate the light beam by moving along the optical axis direction of the projection lens to cooperate with the first movable lens group 34 and the second movable lens group 33 to form high-definition images of different sizes. Figure 6 It is a schematic structural diagram of the light beam in the projection lens transmitted to the projection screen. The size of the image projected by the projection lens 30 onto the projection screen 20 changes within the size range c, and the size c of the projection lens projected onto the projection screen 20 is changed by adjusting the positions of the first movable lens group 34 and the second movable lens group 33 in the projection lens 30.

[0069] Optionally, the third moving lens group 32 includes a ninth lens 321, a tenth lens 322, an eleventh lens 323, a twelfth lens 324, a thirteenth lens 325, a fourteenth lens 326, a fifteenth lens 327, and a sixteenth lens 328 that are sequentially arranged in the direction opposite to the optical path direction 40 of the projection lens; the tenth lens 322 and the eleventh lens 323 are bonded together, the twelfth lens 324 and the thirteenth lens 325 are bonded together, and the fourteenth lens 326 and the fifteenth lens 327 are bonded together, which are used to correct the vertical chromatic aberration and axial chromatic aberration of light; the sixteenth lens 328 is used to converge light. The third moving lens group 32 can move along the optical axis direction of the lens, correct the image plane movement caused by the movement of the variable magnification group, and direct the corrected light to the second moving lens group 33. The ninth lens 321 provides positive spherical aberration, which is used to balance and correct the negative spherical aberration provided by the combined action of the tenth lens 322, the eleventh lens 323, the twelfth lens 324, the thirteenth lens 325, the fourteenth lens 326, the fifteenth lens 327, and the sixteenth lens 328. The bonding method of the tenth lens 322 and the eleventh lens 323 can be cemented. The tenth lens 322 is a spherical positive lens, and the eleventh lens 323 is a spherical positive lens, where the refractive index of the tenth lens 322 is less than that of the eleventh lens 323, and the Abbe number of the tenth lens 322 is greater than that of the eleventh lens 323. The bonding method of the twelfth lens 324 and the thirteenth lens 325 can be cemented. The twelfth lens 324 is a spherical negative lens, and the thirteenth lens 325 is a spherical positive lens, where the refractive index of the twelfth lens 324 is greater than that of the thirteenth lens 325, and the Abbe number of the twelfth lens 324 is less than that of the thirteenth lens 325. The bonding method of the fourteenth lens 326 and the fifteenth lens 327 can be cemented. The fourteenth lens 326 is a spherical negative lens, and the fifteenth lens 327 is a spherical positive lens, where the refractive index of the fourteenth lens 326 is greater than that of the fifteenth lens 327, and the Abbe number of the fourteenth lens 326 is less than that of the fifteenth lens 327. The above-mentioned multiple cemented lenses can correct the vertical chromatic aberration and axial chromatic aberration of the light beam under different focal length conditions. Among them, the axial chromatic aberration is caused by the different imaging positions of the lens for light of each wavelength, so that when imaging finally, the focal planes of the images of different colors of light cannot coincide, and the polychromatic light spreads to form chromatic dispersion. The vertical chromatic aberration is due to the different heights of the chief rays of different colors of light at off-axis points from the intersection point with the Gaussian image plane. This color difference in image height is the vertical chromatic aberration. The sixteenth lens 328 is located at one end close to the light valve assembly and is used to converge the light incident from the rear lens group.

[0070] In addition, the projection lens further includes an aperture stop 320, which is located between the ninth lens and the tenth lens. The aperture stop 320 is a diaphragm that limits the imaging light beam in the optical system and is an element with a light-passing hole in the center. In this application, the aperture stop 320 is placed between the ninth lens and the tenth lens. The aperture stop 320 can also be located between other lenses, and the embodiments of this application do not limit this here.

[0071] The rear lens group 31 includes a seventeenth lens 311 arranged in sequence in the opposite direction of the optical path direction 40 of the projection lens. The rear lens group 31 is close to the light valve assembly 50. The seventeenth lens 311 is configured to receive the light emitted by the light valve assembly 50, correct the excess aberration amount of the light, and direct the light to the third moving lens group 32 after collimating the light.

[0072] Optionally, the first lens is a convex-concave positive lens, the second lens is a biconvex positive lens, the third lens is a convex-concave positive lens, the seventh lens is a biconcave negative lens, the eighth lens is a biconvex positive lens, the ninth lens is a biconvex positive spherical lens, the tenth lens is a biconvex positive spherical lens, the eleventh lens is a convex-concave positive lens, the twelfth lens is a biconcave negative lens, the thirteenth lens is a biconvex positive lens, the fourteenth lens is a biconcave negative lens, the fifteenth lens is a biconvex positive lens, the sixteenth lens is a biconvex positive lens, and the seventeenth lens is a convex-concave positive lens. A lens is an optical element made of a transparent material with a surface that is a part of a spherical surface. The above are the specific shapes of each lens in the embodiments of this application. Lenses have different convex and concave forms and can perform various functions such as collimating, contracting the light beam, and compensating the optical path while transmitting the light beam. Different combinations of multiple lenses can obtain different imaging effects, and the embodiments of this application do not limit the specifications and quantities of the lenses here.

[0073] Optionally, the total length of the projection lens is L0, the length of the front lens group is L1, the length of the first moving lens group is L2, the length of the second moving lens group is L3, the length of the third moving lens group is L4, and the length of the rear lens group is L5;

[0074] L1 satisfies the formula 0.1 < |L1 / L0| < 0.2;

[0075] L2 satisfies the formula 0.15 < |L2 / L0| < 0.25;

[0076] L3 satisfies the formula 0.2 < |L3 / L0| < 0.3;

[0077] L4 satisfies the formula 0.26 < |L4 / L0| < 0.42;

[0078] L5 satisfies the formula 0.01 < |L5 / L0| < 0.1.

[0079] The number of lenses in the projection lens and the spacing between the lenses are different, and the length of the projection lens is different, so that the volume of the projection lens is also different. The number of lenses and the arrangement mode between the lenses in the rear lens group 31, the third moving lens group 32, the second moving lens group 33, the first moving lens group 34 and the front lens group 35 in this application satisfy the length ratio range values of the above-mentioned respective lens groups, so that the total length of the projection lens in the embodiment of this application is also within the above-mentioned length ratio range value. Compared with the length of the projection lens in the related art, the length value of the projection lens in the embodiment of this application is smaller, so that the volume of the projection lens in the embodiment of this application is also smaller.

[0080] Optionally, the effective focal length of the front lens group is F1, the effective focal length of the first moving lens group is F2, the effective focal length of the second moving lens group is F3, the effective focal length of the third moving lens group is F4, and the effective focal length of the rear lens group is F5;

[0081] F1 satisfies the formula 2.0 < |F1 / F0| < 6.0;

[0082] F2 satisfies the formula 0.2 < |F2 / F0| < 1.0;

[0083] F3 satisfies the formula 2.8 < |F3 / F0| < 7.2;

[0084] F4 satisfies the formula 1.1 < |F4 / F0| < 4.2;

[0085] F5 satisfies the formula 1.8 < |F5 / F0| < 5.3;

[0086] Where F0 is the effective focal length of the projection lens. The effective focal length is a measure of the convergence or divergence of light in an optical system, referring to the distance from the center of the lens to the focus where the light converges. The effective focal lengths of the rear lens group 31, the third moving lens group 32, the second moving lens group 33, the first moving lens group 34 and the front lens group 35 in the embodiment of this application satisfy the above formula, and can also be other ranges, which are not limited in the embodiment of this application.

[0087] In summary, the embodiment of the present application provides a projection lens including a rear lens group, a third moving lens group, a second moving lens group, a first moving lens group, and a front lens group arranged in sequence along the optical path direction of the projection lens. The rear lens group guides the light emitted from the light valve assembly to the third moving lens group. The third moving lens group guides the received light to the second moving lens group. The second moving lens group guides the received light to the first moving lens group. The first moving lens group guides the received light to the front lens group. The front lens group compensates the light and then guides it to the projection screen. This projection lens can be applied to a laser light source, where the third moving lens group compensates the received light, the second moving lens group can change the angle of the light incident on the first moving lens group, the first moving lens group can adjust the size of the image projected by the projection lens onto the projection screen by moving along the optical axis direction of the projection lens, and the rear lens group and the front lens group can compensate the light by moving to make the final image clearer. The entire projection lens has a simple structure and can achieve high resolution and high-definition imaging while having a small volume. It solves the problem of incomplete performance of the projection lens in the related art and achieves the effect of improving the comprehensiveness of the projection lens performance.

[0088] As Figure 7 shown, it is a schematic structural diagram of a laser projection device provided by an embodiment of the present application.

[0089] Optionally, the laser projection device further includes a light valve assembly 50. The light valve assembly 50 includes a light valve 51 and a galvanometer 52. The galvanometer 52 deflects the light emitted from the light valve 51 and then guides it to the projection lens 30. The light valve assembly 50 may further include a total internal reflection (TIR) prism 53. A digital micromirror device (DMD) is a digital micromirror element. The light valve 51 can guide the light emitted from the TIR prism 53 to the galvanometer 52. The galvanometer 52 deflects the light beam and then guides it to the rear lens group in the projection lens. A galvanometer is usually a flat piece of glass, and through high-frequency vibration, the misaligned transmission of the light beam is achieved. In the related art, in order to improve the resolution of engineering projectors with LED light sources, for engineering projectors with laser light sources, the present application adds a galvanometer in the engineering projectors with laser light sources, which can increase the resolution of the engineering projectors from 1080P in the related art to 4K resolution.

[0090] The back focal length (BFL) refers to the distance from the vertex of the last optical surface of the system to the rear focal point. In the present application, the back focal length is the distance between the light valve assembly and the first lens, and this distance satisfies: 0.15 < BFL / L0 < 2.2.

[0091] Optionally, a laser projection device 60 includes the projection lens 30 in any of the above embodiments. In the projection lens in the related art, the lens structure is complex, the volume of the projection lens is large, and the resolution is low. The laser projection device 60 in the present application is an engineering projection device with a laser light source, which can withstand a light flux of more than 5000 lm, is compatible with a large projection range of 40-300 inches, has high brightness and high resolution, and is applicable to different temperature conditions. The adjustment mechanism of the projection lens is simple, and the length of the projection lens is short, so the volume is small. At the same time, it is also applicable to light valves of different specifications. In addition, in one embodiment, the projection lens 30 in the present application can achieve an effective focal length of 21.95-43.9 mm, the resolution can reach 93 lp / mm, and the projection ratio (projection distance / picture length direction) is 1.0-4.0.

[0092] In summary, the embodiment of the present application provides a laser projection device, including a projection lens with a rear lens group, a third moving lens group, a second moving lens group, a first moving lens group, and a front lens group arranged in sequence along the optical path direction of the projection lens. The rear lens group guides the light emitted from the light valve assembly to the third moving lens group, the third moving lens group guides the received light to the second moving lens group, the second moving lens group guides the received light to the first moving lens group, the first moving lens group guides the received light to the front lens group, and the front lens group guides the light to the projection screen after compensation. This projection lens can be applied to a laser light source, wherein the third moving lens group compensates the received light, the second moving lens group can change the angle of the light incident on the first moving lens group, the first moving lens group can adjust the size of the picture output by the projection lens to the projection screen by moving along the optical axis direction of the projection lens, and the rear lens group and the front lens group can compensate the light by moving to make the final image clearer. The entire projection lens has a simple structure and can achieve high resolution and high-definition imaging while having a small volume. It solves the problem that the performance of the projection lens in the related art is not comprehensive, and achieves the effect of improving the comprehensiveness of the projection lens performance.

[0093] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A projection lens, characterized in that, The projection lens is composed of a rear lens group, a third moving lens group, a second moving lens group, a first moving lens group, and a front lens group, which are sequentially arranged along the optical path direction of the projection lens; The rear lens group is used to receive the light emitted by the light valve assembly, and after correcting and collimating the light, direct it to the third moving lens group; The third moving lens group, the second moving lens group, and the first moving lens group can move along the optical axis direction of the projection lens. The third moving lens group compensates the received light and directs it to the second moving lens group. The second moving lens group is used to change the angle of incidence of the light onto the first moving lens group. The first moving lens group directs the received light to the front lens group and is used to adjust the size of the image projected onto the projection screen by the projection lens; The front lens group is used to compensate the received light and direct the light to the projection screen; The effective focal length of the front lens group is F1, the effective focal length of the first moving lens group is F2, the effective focal length of the second moving lens group is F3, the effective focal length of the third moving lens group is F4, and the effective focal length of the rear lens group is F5; F1 satisfies the formula 2.0 < |F1 / F0| < 6.0; F2 satisfies the formula 0.2 < |F2 / F0| < 1.0; F3 satisfies the formula 2.8 < |F3 / F0| < 7.2; F4 satisfies the formula 1.1 < |F4 / F0| < 4.2; F5 satisfies the formula 1.8 < |F5 / F0| < 5.3; where F0 is the effective focal length of the projection lens; The front lens group is composed of a first lens, a second lens, and a third lens, which are sequentially arranged in the reverse direction of the optical path direction of the projection lens. The first lens is a convex-concave positive lens, the second lens is a biconvex positive lens, and the third lens is a convex-concave positive lens; The first moving lens group is composed of a fourth lens, a fifth lens, and a sixth lens, which are sequentially arranged in the reverse direction of the optical path direction of the projection lens. The fourth lens is a convex-concave positive lens, the fifth lens is a convex-concave positive spherical lens, and the sixth lens is a biconcave negative spherical lens; The second moving lens group is composed of a seventh lens and an eighth lens, which are sequentially arranged in the reverse direction of the optical path direction of the projection lens. The seventh lens is a biconcave negative lens, and the eighth lens is a biconvex positive lens; The third moving lens group is composed of a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, a fifteenth lens, and a sixteenth lens, which are sequentially arranged in the reverse direction of the optical path direction of the projection lens. The ninth lens is a biconvex positive spherical lens, the tenth lens is a biconvex positive spherical lens, the eleventh lens is a convex-concave positive lens, the twelfth lens is a biconcave negative lens, the thirteenth lens is a biconvex positive lens, the fourteenth lens is a biconcave negative lens, the fifteenth lens is a biconvex positive lens, and the sixteenth lens is a biconvex positive lens; The rear lens group is composed of a seventeenth lens, which is sequentially arranged in the reverse direction of the optical path direction of the projection lens. The seventeenth lens is a concave-convex positive lens.

2. The projection lens according to claim 1, characterized in that The first lens and the second lens are attached to provide an orthodontic variable. The refractive index of the first lens is greater than that of the second lens, and the Abbe number of the first lens is less than that of the second lens. The curvature of the surface of the third lens adjacent to the second lens is less than the curvature of the surface of the third lens remote from the second lens. The third lens is used to correct the direction of the light rays and provide a negative distortion variable.

3. The projection lens according to claim 2, wherein The convex surfaces of the fourth lens and the fifth lens both face the front lens group, and the more concave one of the two concave surfaces of the sixth lens faces the concave surface of the fifth lens. The fifth lens and the sixth lens provide an orthodontic variable, and the fourth lens provides a negative distortion variable.

4. The projection lens according to claim 3, characterized in that, The seventh lens and the eighth lens cooperate to correct the spherical aberration and coma of the light rays.

5. The projection lens according to claim 4, characterized in that, The tenth lens and the eleventh lens are attached, the twelfth lens and the thirteenth lens are attached, and the fourteenth lens and the fifteenth lens are attached to correct the lateral chromatic aberration and axial chromatic aberration of the light rays. The sixteenth lens is used to converge the light rays. The projection lens further includes an aperture stop, and the aperture stop is located between the ninth lens and the tenth lens.

6. The projection lens according to claim 1, characterized in that, The total length of the projection lens is L0, the length of the front lens group is L1, the length of the first movable lens group is L2, the length of the second movable lens group is L3, the length of the third movable lens group is L4, and the length of the rear lens group is L5. L1 satisfies the formula 0.1 < |L1 / L0| < 0.2; L2 satisfies the formula 0.15 < |L2 / L0| < 0.25; L3 satisfies the formula 0.2 < |L3 / L0| < 0.3; L4 satisfies the formula 0.26 < |L4 / L0| < 0.42; L5 satisfies the formula 0.01 < |L5 / L0| < 0.

1.

7. A laser projection device, characterized in that, Including the projection lens according to any one of claims 1-6.

8. The laser projection device according to claim 7, characterized in that, The laser projection device further includes a light valve assembly, and the light valve assembly includes a light valve and a galvanometer scanner. The galvanometer scanner deflects the light rays emitted from the light valve and guides them to the projection lens.

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