DLP three-dimensional scanning lens

Abstract

The DLP three-dimensional scanning lens comprises a front lens group (10), a diaphragm (20), a rear lens group (30), an equivalent prism (40) and an image display device (50) which are sequentially arranged from an object side to an image source side, the central axes of the front lens group (10), the diaphragm (20), the rear lens group (30), the equivalent prism (40) and the image display device (50) are located on an optical axis; from an object side to an image source side, the front lens group (10) comprises a meniscus positive lens (11), a meniscus negative lens (12), a biconcave negative lens (13), a meniscus positive lens (14) and a plano-convex positive lens (15) which are arranged in sequence; from the object side to the image source side, the rear lens group (30) comprises a cemented negative lens (31), a meniscus positive lens (32), a plano-convex positive lens (33) and a biconvex positive lens (34) which are arranged in sequence; the cemented negative lens (31) is composed of a first lens and a second lens. The lens can clearly project an image on an image display device to an object, and has the characteristics of high resolution, small field curvature and small distortion.

Description

Technical Field

[0001] The utility model relates to a structured light three-dimensional scanning technology, in particular to a DLP three-dimensional scanning lens. Background Art

[0002] 3D scanning is a stereoscopic vision measurement technology that integrates optical, mechanical, electrical and computer technologies. It is mainly used to scan the spatial shape, structure and color of an object to obtain 3D data of the object surface. The structured light 3D measurement system mainly consists of five parts: image acquisition, camera calibration, feature extraction, stereo matching and 3D point cloud computing and processing system. Among them, camera calibration, feature extraction and stereo matching are the key technologies of the structured light 3D measurement system. The principle of structured light scanning measurement technology is as follows: the light source projects the grating stripes onto the object to be measured through the projection system, and the measurement stripes are modulated by the surface of the object to be measured. The camera collects the measurement stripe image, decodes and calculates the phase, and finally uses the epipolar constraint criterion and stereo vision technology to obtain the 3D data of the measured surface.

[0003] Among them, the optical engine is the core component of the structured light 3D scanning system, and the image display device is one of the most critical parts in the optical engine. It is a digital image chip exclusively mastered and developed by Texas Instruments (TI) in the United States. It integrates micro-electromechanical structure circuit units and is made of COMS and SRAM memory units. When the image display device is working normally, light is irradiated onto the image display device through optical lenses. The tiny lenses on the surface of the image display device that can be controlled by circuits will reflect light by rotating, and finally form an image through the projection lens, thereby forming structured light. Therefore, the projection lens directly determines the working distance, projection format, and projection accuracy of the structured light 3D scanning system.

[0004] Most DLP 3D scanning lenses on the market often face trade-offs in design, and it is difficult to optimize key performance indicators such as working distance, projection format and projection accuracy at the same time. In addition, the optical components and structural parts of these lenses are mostly made of plastic, which helps to reduce costs and weight, but also brings challenges in stability, especially after temperature changes or long-term use, there may be a certain degree of performance fluctuation or accuracy reduction. Utility Model Content

[0005] The utility model provides a DLP three-dimensional scanning lens to solve the above technical problems, including:

[0006] A front lens group, an aperture, a rear lens group, an equivalent prism, and an image display device are arranged in sequence from the object side to the image source side; the central axes of the front lens group, the aperture, the rear lens group, the equivalent prism, and the image display device are all located on the optical axis;

[0007] From the object side to the image source side, the front lens group includes a meniscus positive lens with positive focal power, a meniscus negative lens with negative focal power, a biconcave negative lens with negative focal power, a meniscus positive lens with positive focal power, and a plano-convex positive lens with positive focal power, which are arranged in sequence; from the object side to the image source side, the rear lens group includes a cemented negative lens with negative focal power, a meniscus positive lens with positive focal power, a plano-convex positive lens with positive focal power, and a biconvex positive lens with positive focal power, which are arranged in sequence;

[0008] The cemented negative lens is composed of a first lens and a second lens cemented together; specifically, the lens combination of the front lens group is used to control the direction of light to improve the lens resolution; the cemented negative lens in the rear lens group is used to correct phase aberration.

[0009] In one embodiment, the first lens of the cemented negative lens is a double concave negative lens, and the second lens is a double convex positive lens.

[0010] In one embodiment, one side of the double convex positive lens of the cemented negative lens faces the image source side.

[0011] In one embodiment, in the front lens group, the object side surface and the image source side surface of the meniscus positive lens have a curvature radius of 16.088-17.782 mm and 56.73-62.702 mm, respectively; the object side surface and the image source side surface of the meniscus negative lens have a curvature radius of 23.522-25.998 mm and 9.58-10.588 mm, respectively; the object side surface and the image source side surface of the double concave negative lens have a curvature radius of -44.898--40.622 mm and 14.393-15.909 mm, respectively; the object side surface and the image source side surface of the meniscus positive lens have a curvature radius of -46.028--41.644 mm and -24.523--22.187 mm, respectively; the object side surface and the image source side surface of the plano-convex positive lens have a curvature radius of 17.326-19.15 mm and are infinite, respectively;

[0012] As mentioned above, the radius of curvature of the aperture is infinite;

[0013] In the rear lens group, the curvature radius of the object side surface of the cemented negative lens is -12.774 to -11.557 mm, the curvature radius of the cemented surface of the first lens and the second lens is 24.544 to 27.128 mm, and the curvature radius of the image source side surface is -14.028 to -12.692 mm; the curvature radii of the object side surface and the image source surface of the meniscus positive lens are -79.496 to -71.925 mm and -23.256 to -21.0416 mm, respectively; the curvature radii of the object side surface and the image source surface of the plano-convex positive lens are infinite and -63.116 to -57.105, respectively; the curvature radii of the object side surface and the image source surface of the biconvex positive lens are 32.227 to 35.619 mm and -64.514 to -58.37 mm, respectively;

[0014] The fact that the radius of curvature is infinite means that the curvature of the surface is 0, that is, the surface is a plane.

[0015] In one embodiment, in the front lens group, the center thickness of the meniscus positive lens on the optical axis is 6.423-7.099 mm, and the air gap between the meniscus negative lens and the double concave negative lens on the optical axis is 0.914-1.01 mm; the center thickness of the meniscus negative lens on the optical axis is 1.937-2.141 mm, and the air gap between the meniscus negative lens and the double concave negative lens on the optical axis is 3.556-3.93 mm; the center thickness of the double concave negative lens on the optical axis is 1.1 4~1.26mm, the air spacing between the meniscus positive lens and the optical axis is 1.949~2.155mm; the center thickness of the meniscus positive lens on the optical axis is 2.835~3.133mm, and the air spacing between the meniscus positive lens and the plano-convex positive lens on the optical axis is 3.029~3.347mm; the center thickness of the plano-convex positive lens on the optical axis is 4.82~5.328mm, and the air spacing between the plano-convex positive lens and the aperture on the optical axis is 4.875~5.389mm;

[0016] The air gap between the aperture and the cemented negative lens on the optical axis is 5.874 to 6.492 mm;

[0017] In the rear mirror group, the center thickness of the first lens of the cemented negative lens on the optical axis is 1.14-1.26 mm, the center thickness of the second lens on the optical axis is 4.304-4.758 mm, and the air interval between the second lens and the meniscus positive lens on the optical axis is 0.218-0.24 mm; the center thickness of the meniscus positive lens on the optical axis is 2.817-3.113 mm, and the air interval between the second lens and the plano-convex positive lens on the optical axis is 0.498-0.55 mm; the center thickness of the plano-convex positive lens on the optical axis is 2.103-2.325 mm, and the air interval between the second lens and the biconvex positive lens on the optical axis is 0.568-0.628 mm; the center thickness of the biconvex positive lens on the optical axis is 3.77-4.166 mm, and the air interval between the second lens and the prism on the optical axis is 6.175-6.825 mm;

[0018] The center thickness of the prism on the optical axis is 17.575-19.425 mm, and the air gap between the prism and the image display device on the optical axis is 0.95-0.105 mm; the center thickness of the image display device substrate on the optical axis is 0.618-0.682 mm, and the air gap between the image display device and the micro mirror surface on the optical axis is 0.286-0.316 mm.

[0019] In one embodiment, in the front lens group, the refractive index of the meniscus positive lens is 1.682 to 1.859; the refractive index of the meniscus negative lens is 1.682 to 1.859; the refractive index of the double concave negative lens is 1.758 to 1.943; the refractive index of the meniscus positive lens is 1.615 to 1.785; the refractive index of the plano-convex positive lens is 1.758 to 1.943;

[0020] In the rear mirror assembly, the refractive index of the first lens of the cemented negative lens is 1.72-1.901, and the refractive index of the second lens is 1.416-1.565; the refractive index of the meniscus positive lens is 1.416-1.565; the refractive index of the plano-convex positive lens is 1.644-1.817; and the refractive index of the biconvex positive lens is 1.682-1.859;

[0021] The refractive index of the equivalent prism is 1.539-1.701; the refractive index of the image display device is 1.444-1.596.

[0022] In one embodiment, in the front lens group, the Abbe number of the meniscus positive lens is 47.12-52.08; the Abbe number of the meniscus negative lens is 47.12-52.08; the Abbe number of the double concave negative lens is 22.61-24.99; the Abbe number of the meniscus positive lens is 28.595-31.605; the Abbe number of the plano-convex positive lens is 22.61-24.99;

[0023] In the rear lens group, the Abbe number of the first lens of the cemented negative lens is 24.225-26.775, the Abbe number of the second lens is 66.88-73.92; the Abbe number of the meniscus positive lens is 66.88-73.92; the Abbe number of the plano-convex positive lens is 48.545-53.655; the Abbe number of the biconvex positive lens is 47.12-52.08;

[0024] The Abbe number of the equivalent prism is 57.38-63.42; the Abbe number of the image display device is 60.99-67.41.

[0025] In one embodiment, in the front lens group, the semi-diameters of the object side surface and the image source side surface of the meniscus positive lens are 13.063-14.438 mm and 12.35-13.65 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the meniscus negative lens are 10.45-11.55 mm and 6.926-7.655 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the double concave negative lens are 6.926-7.655 mm and 6.318-6.983 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the meniscus positive lens are 6.365-7.035 mm and 8.075-8.925 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the plano-convex positive lens are 8.075-8.925 mm and 8.075-8.925 mm, respectively;

[0026] The semi-diameter of the aperture is 3.551-3.925 mm;

[0027] In the rear lens group, the semi-diameter of the object side surface of the cemented negative lens is 5.225-5.775 mm, the semi-diameter of the cemented surface of the first lens and the second lens is 7.125-7.875 mm, and the semi-diameter of the image source side surface is 7.125-7.875 mm; the semi-diameters of the object side surface and the image source surface of the meniscus positive lens are 8.075-8.925 mm and 9.5-10.5 mm respectively; the semi-diameters of the object side surface and the image source surface of the plano-convex positive lens are 10.45-11.55 mm and 10.45-11.55 mm respectively; the semi-diameters of the object side surface and the image source surface of the biconvex positive lens are 10.45-11.55 mm and 10.45-11.55 mm respectively;

[0028] The semi-diameters of the object side surface and the image source surface of the prism are 8.227-9.093 mm and 6.037-6.673 mm respectively; the semi-diameters of the object side surface and the image source surface of the image display device are 5.842-6.456 mm and 5.767-6.374 mm respectively, and the semi-diameter of the micro-mirror surface of the image display device is 5.71-6.311 mm;

[0029] The semi-diameter refers to half of the outer diameter of the lens.

[0030] In one embodiment, the image display device may be any one of DMD, LCD, LCOS and the like.

[0031] In one embodiment, the working distance of the DLP three-dimensional scanning lens is: WD=630-770 mm; the projection ratio is: TR=1.82; and the aperture size is: F / #=2.4.

[0032] The above-mentioned scheme provided by the embodiment of the utility model adopts a lens focal length combination of a positive lens, a negative lens, a negative lens, a positive lens, a positive lens, and a negative lens, a positive lens, a positive lens, and a positive lens. In addition, a cemented lens is added to the rear lens group. This reasonable lens arrangement can magnify the image on the image display device and clearly image it on the light screen, which greatly improves the correction of aberrations and has the characteristics of high resolution, small field curvature, and small distortion. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of an optical system of a DLP three-dimensional scanning lens according to an embodiment of the utility model;

[0034] Figure 2 This is an MTF curve diagram of a DLP three-dimensional scanning lens according to an embodiment of the utility model at an aperture of F / 2.4 and a spatial frequency of 66 line pairs;

[0035] Figure 3 This is a point diagram of a DLP three-dimensional scanning lens according to an embodiment of the utility model at an aperture of F / 2.4;

[0036] Figure 4 This is a field curvature and distortion curve diagram of a DLP three-dimensional scanning lens according to an embodiment of the utility model. DETAILED DESCRIPTION

[0037] The solution provided in this specification is described below in conjunction with the accompanying drawings.

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0039] In the description of the embodiments of the present application, words such as "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a concrete way.

[0040] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, B exists alone, and A and B exist at the same time. In addition, unless otherwise specified, the term "plurality" means two or more.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. The terms "include", "comprises", "has" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0042] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments.

[0043] Figure 1 The optical system schematic diagram of a DLP three-dimensional scanning lens provided according to an embodiment of the utility model comprises: a front lens group 10, an aperture 20, a rear lens group 30, an equivalent prism 40, and an image display device 50 arranged in sequence from the object side to the image source side; the central axes of the front lens group 10, the aperture 20, the rear lens group 30, the equivalent prism 40, and the image display device 50 are all located on the optical axis; from the object side to the image source side, the front lens group 10 comprises a positive meniscus lens 11 with positive focal length, a negative meniscus lens 12 with negative focal length, a double concave negative lens 13 with negative focal length, A meniscus positive lens 14 with positive optical power, a plano-convex positive lens 15 with positive optical power; from the object side to the image source side, the rear lens group 30 includes a cemented negative lens 31 with negative optical power, a meniscus positive lens 32 with positive optical power, a plano-convex positive lens 33 with positive optical power, and a double convex positive lens 34 with positive optical power, which are arranged in sequence; wherein the cemented negative lens 31 is composed of a first lens and a second lens cemented together; specifically, the lens combination of the front lens group 10 is used to control the direction of light to improve the lens resolution; the cemented negative lens 31 in the rear lens group 30 is used to correct phase aberration.

[0044] The arrangement and combination of the lenses in the front lens group can improve the lens resolution by changing the light path and controlling the angle of light entering the lens, and can also maintain good lens resolution under light incident at large angles. The cemented negative lens in the rear lens group can assist in correcting spherical aberration (a phenomenon in which the center and edge focus points are inconsistent due to the spherical curve of the lens surface), and can optimize the focus of the entire image plane, so that good clarity can be maintained from the center to the edge, achieving the effect of small field curvature and small distortion.

[0045] Preferably, the first lens of the cemented negative lens 31 is a biconcave negative lens, and the second lens is a biconvex positive lens.

[0046] Preferably, the double convex positive lens side of the cemented negative lens 31 faces the image source side.

[0047] Preferably, the object side surface and image source side surface of the meniscus positive lens 11 have curvature radii of 16.088-17.782 mm and 56.73-62.702 mm, respectively; the object side surface and image source side surface of the meniscus negative lens 12 have curvature radii of 23.522-25.998 mm and 9.58-10.588 mm, respectively; the object side surface and image source side surface of the double concave negative lens 13 have curvature radii of -44.898--40.622 mm and 14.393-15.909 mm, respectively; the object side surface and image source side surface of the meniscus positive lens 14 have curvature radii of -46.028--41.644 mm and -24.523--22.187 mm, respectively; the object side surface and image source side surface of the plano-convex positive lens 15 have curvature radii of 17.326-19.15 mm and are infinite, respectively;

[0048] As mentioned above, the radius of curvature of the aperture 20 is infinite;

[0049] The object side surface of the cemented negative lens 31 has a curvature radius of -12.774 to -11.557 mm, the curvature radius of the cemented surface of the first lens and the second lens is 24.544 to 27.128 mm, and the curvature radius of the image source side surface is -14.028 to -12.692 mm; the curvature radii of the object side surface and the image source surface of the meniscus positive lens 32 are -79.496 to -71.925 mm and -23.256 to -21.0416 mm, respectively; the curvature radii of the object side surface and the image source surface of the plano-convex positive lens 33 are infinite and -63.116 to -57.105, respectively; the curvature radii of the object side surface and the image source surface of the biconvex positive lens 34 are 32.227 to 35.619 mm and -64.514 to -58.37 mm, respectively;

[0050] The fact that the radius of curvature is infinite means that the curvature of the surface is 0, that is, the surface is a plane.

[0051] Preferably, the central thickness of the meniscus positive lens 11 on the optical axis is 6.423-7.099 mm, and the air gap between the meniscus negative lens 12 and the meniscus negative lens 12 on the optical axis is 0.914-1.01 mm; the central thickness of the meniscus negative lens 12 on the optical axis is 1.937-2.141 mm, and the air gap between the meniscus negative lens 12 and the biconcave negative lens 13 on the optical axis is 3.556-3.93 mm; the central thickness of the biconcave negative lens 13 on the optical axis is 1.14-1.26 mm, the air gap between the meniscus positive lens 14 and the optical axis is 1.949-2.155 mm; the center thickness of the meniscus positive lens 14 on the optical axis is 2.835-3.133 mm, and the air gap between the meniscus positive lens 14 and the plano-convex positive lens 15 on the optical axis is 3.029-3.347 mm; the center thickness of the plano-convex positive lens 15 on the optical axis is 4.82-5.328 mm, and the air gap between the meniscus positive lens 14 and the aperture 20 on the optical axis is 4.875-5.389 mm;

[0052] The air gap between the aperture 20 and the cemented negative lens 31 on the optical axis is 5.874-6.492 mm;

[0053] The center thickness of the first lens of the cemented negative lens 31 on the optical axis is 1.14-1.26mm, the center thickness of the second lens on the optical axis is 4.304-4.758mm, and the air gap between the second lens and the meniscus positive lens 32 on the optical axis is 0.218-0.24mm; the center thickness of the meniscus positive lens 32 on the optical axis is 2.817-3.113mm, and the air gap between the second lens and the plano-convex positive lens 33 on the optical axis is 0.498-0.55mm; the center thickness of the plano-convex positive lens 33 on the optical axis is 2.103-2.325mm, and the air gap between the second lens and the biconvex positive lens 34 on the optical axis is 0.568-0.628mm; the center thickness of the biconvex positive lens 34 on the optical axis is 3.77-4.166mm, and the air gap between the second lens and the prism 40 on the optical axis is 6.175-6.825mm;

[0054] The center thickness of the prism 40 on the optical axis is 17.575-19.425 mm, and the air gap between the prism 40 and the image display device 50 on the optical axis is 0.95-0.105 mm; the center thickness of the substrate of the image display device 50 on the optical axis is 0.618-0.682 mm, and the air gap between the substrate and the micromirror surface of the image display device 50 on the optical axis is 0.286-0.316 mm.

[0055] Preferably, the refractive index of the meniscus positive lens 11 is 1.682-1.859; the refractive index of the meniscus negative lens 12 is 1.682-1.859; the refractive index of the double concave negative lens 13 is 1.758-1.943; the refractive index of the meniscus positive lens 14 is 1.615-1.785; the refractive index of the plano-convex positive lens 15 is 1.758-1.943;

[0056] The refractive index of the first lens of the cemented negative lens 31 is 1.72-1.901, and the refractive index of the second lens is 1.416-1.565; the refractive index of the meniscus positive lens 32 is 1.416-1.565; the refractive index of the plano-convex positive lens 33 is 1.644-1.817; the refractive index of the biconvex positive lens 34 is 1.682-1.859;

[0057] The refractive index of the equivalent prism 40 is 1.539-1.701; the refractive index of the image display device 50 is 1.444-1.596.

[0058] Preferably, the Abbe number of the meniscus positive lens 11 is 47.12-52.08; the Abbe number of the meniscus negative lens 12 is 47.12-52.08; the Abbe number of the double concave negative lens 13 is 22.61-24.99; the Abbe number of the meniscus positive lens 14 is 28.595-31.605; the Abbe number of the plano-convex positive lens 15 is 22.61-24.99;

[0059] The Abbe number of the first lens of the cemented negative lens 31 is 24.225-26.775, and the Abbe number of the second lens is 66.88-73.92; the Abbe number of the meniscus positive lens 32 is 66.88-73.92; the Abbe number of the plano-convex positive lens 33 is 48.545-53.655; the Abbe number of the biconvex positive lens 34 is 47.12-52.08;

[0060] The Abbe number of the equivalent prism 40 is 57.38-63.42; the Abbe number of the image display device 50 is 60.99-67.41.

[0061] Preferably, the semi-diameters of the object side surface and the image source side surface of the meniscus positive lens 11 are 13.063-14.438 mm and 12.35-13.65 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the meniscus negative lens 12 are 10.45-11.55 mm and 6.926-7.655 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the double concave negative lens 13 are 6.926-7.655 mm and 6.318-6.983 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the meniscus positive lens 14 are 6.365-7.035 mm and 8.075-8.925 mm, respectively; the semi-diameters of the object side surface and the image source side surface of the plano-convex positive lens 15 are 8.075-8.925 mm and 8.075-8.925 mm, respectively;

[0062] The semi-diameter of the aperture 20 is 3.551-3.925 mm;

[0063] The semi-diameter of the object side surface of the cemented negative lens 31 is 5.225-5.775mm, the semi-diameter of the cemented surface of the first lens and the second lens is 7.125-7.875mm, and the semi-diameter of the image source side surface is 7.125-7.875mm; the semi-diameters of the object side surface and the image source surface of the meniscus positive lens 32 are 8.075-8.925mm and 9.5-10.5mm respectively; the semi-diameters of the object side surface and the image source surface of the plano-convex positive lens 33 are 10.45-11.55mm and 10.45-11.55mm respectively; the semi-diameters of the object side surface and the image source surface of the biconvex positive lens 34 are 10.45-11.55mm and 10.45-11.55mm respectively;

[0064] The semi-diameters of the object side surface and the image source surface of the prism 40 are 8.227-9.093 mm and 6.037-6.673 mm respectively; the semi-diameters of the object side surface and the image source surface of the image display device 50 are 5.842-6.456 mm and 5.767-6.374 mm respectively, and the semi-diameter of the micromirror surface of the image display device 50 is 5.71-6.311 mm.

[0065] The semi-diameter refers to half of the outer diameter of the lens.

[0066] Preferably, the image display device 50 in the DLP three-dimensional scanning lens can be any one of DMD, LCD, LCOS and the like.

[0067] Preferably, the working distance of the DLP three-dimensional scanning lens is: WD=630-770 mm; the projection ratio is: TR=1.82; and the aperture size is: F / #=2.4.

[0068] In the embodiment of the present invention, both the front lens group 10 and the rear lens group 30 use high refractive index optical glass and low dispersion optical glass to correct optical aberrations. It should be understood that a single lens in the front lens group 10 or the rear lens group 30 can have both high refractive index and low dispersion properties; or different lenses in the front lens group 10 or the rear lens group 30 can use glasses with different properties, for example: the positive meniscus lens 11 in the front lens group 10 uses high refractive index optical glass, and the negative meniscus lens 12 uses low dispersion optical glass.

[0069] The design wavelengths of the utility model are g (435.8nm), F (486.1nm), d (587.6nm), and C (656.3nm).

[0070] In the embodiment of the utility model, the adjustable diaphragm 20 is used to realize continuous adjustment of the aperture, which helps to eliminate astigmatism, distortion and chromatic aberration of magnification. It can be a fan-shaped metal adjustable diaphragm, which can be set between the front and rear lens groups.

[0071] The working principle of the embodiment of the utility model is: by collecting the light from the image display device into the lens, refracting the light through the rear lens group and the foreground group, and correcting various aberrations, finally forming an enlarged and clear image at the working distance of the lens. At the same time, in order to balance the relationship between contrast and light flux, the aperture between the foreground group and the rear lens group can be fine-tuned to achieve a balance between the two.

[0072] It can be understood that the embodiment of the utility model can clearly image the image on the DMD on the light screen after magnification; the lens layout of the lens is reasonable, the front lens group adopts a combination of positive lens, negative lens, negative lens, positive lens, positive lens and a reasonable lens focal length combination; the rear lens group adopts a combination of cemented negative lens, positive lens, positive lens, positive lens and a reasonable lens focal length combination, which is conducive to the realization of this goal. Among them, the arrangement and combination of the front lens group can control the reasonable change of the direction of light, improve the resolution of the lens, and maintain a good lens resolution under light incident at a large angle; in addition, the addition of a cemented lens to the rear lens group greatly improves the correction of aberrations, and achieves the effect of small field curvature and small distortion. And the front and rear lens groups both use high refractive index and low dispersion materials, which also provides a good foundation for the correction of aberrations. And the combination of high refractive index and low dispersion materials and low refractive index and high dispersion materials used in the rear lens group can correct aberrations better.

[0073] The feasibility of the technical solution in the embodiment of the present invention is described below in conjunction with a specific example. The specific parameters of the example are shown in the following table:

[0074]

[0075]

[0076] Table 1

[0077] Among them, the data in rows 1 and 2 refer to the data of lens 11, the data in rows 3 and 4 refer to the data of lens 12, the data in rows 5 and 6 refer to the data of lens 13, the data in rows 7 and 8 refer to the data of lens 14, the data in rows 9 and 10 refer to the data of lens 15, the data in row 11 refers to the data of aperture 20, the data in rows 12, 13 and 14 refer to the data of lens 31, the data in rows 15 and 16 refer to the data of lens 32, the data in rows 17 and 18 refer to the data of lens 33, the data in rows 19 and 20 refer to the data of lens 34, the data in rows 21 and 22 refer to the data of prism 40, the data in rows 23 and 24 refer to the data of DMD 50, and the data in row 25 refers to the data of micromirror I MA of DMD 50.

[0078] In addition, when reading the curvature radius data, the curvature radius data in the upper row of the lens refers to the curvature radius of the object side of the lens, and the curvature radius data in the lower row refers to the curvature radius of the image source side of the lens. For example: the curvature radius data in row number 1 refers to the curvature radius of the object side of lens 11, and the curvature radius data in row number 2 refers to the curvature radius of the image source side of lens 11. What is special is that lens 31 is formed by two lenses glued together, the data in row 12 refers to the object side of the first lens, the data in row 13 refers to the glued surface of the first lens and the second lens, and the data in row 14 refers to the image source side of the second lens; when reading the interval thickness data, the interval thickness data in the upper row of the lens refers to the center thickness of the lens itself on the optical axis, and the interval thickness data in the lower row refers to the interval distance between the lens located on the optical axis and the lens adjacent to the image source side. What is special is that lens 31 is formed by two lenses glued together, the data in row 12 refers to the center thickness of the first lens itself on the optical axis, the data in row 13 refers to the center thickness of the second lens itself on the optical axis, and the data in row 14 refers to the interval distance between the second lens and the lens adjacent to the image source side on the optical axis; the data in the refractive index and Abbe number columns are easy to understand and will not be repeated here; the semi-diameter data refers to half of the outer diameter of the lens, and the understanding in Table 1 is similar to that of the curvature radius column data and will not be repeated here.

[0079] Figure 2This is the MTF curve corresponding to the DLP three-dimensional scanning lens described in the above embodiment of the utility model at an aperture of F / 2.4 and a spatial frequency of 66 line pairs. In the figure, when the cutoff frequency is 66 line pairs, the MTF value is greater than 0.7 (this three-dimensional scanning lens is mainly used on a 0.45-inch DMD, the unit size of the micromirror is 7.6um, and the corresponding cutoff frequency is 66 line pairs), and the curve is smooth and compact, indicating that the lens has clear, uniform imaging and high quality. It can be seen that the imaging quality of the lens of the embodiment of the utility model fully meets the pixel size of the DMD.

[0080] Figure 3 This is a point diagram of the DLP three-dimensional scanning lens described in the above embodiment of the utility model at an aperture of F / 2.4. As can be seen from the figure, the diameter of the lens's circle of confusion is smaller than the DMD pixel size of 7.6um, indicating that the lens has a very good image quality, high lens clarity, high resolution, and good imaging effect.

[0081] Figure 4 This is a graph of the field curvature and distortion of the DLP 3D scanning lens described in the above embodiment of the utility model. It can be seen from the graph that the field curvature of the lens is less than 0.04mm and the distortion is less than 0.1%. Therefore, it can be seen that the 3D scanning projection lens of the embodiment of the utility model meets the requirements for distortion.

[0082] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solution of the present invention should be included in the scope of protection of the present invention.

Claims

1. A DLP three-dimensional scanning lens, characterized in that: include: A front lens group (10), an aperture (20), a rear lens group (30), an equivalent prism (40), and an image display device (50) are sequentially arranged from the object side to the image source side; the central axes of the front lens group (10), the aperture (20), the rear lens group (30), the equivalent prism (40), and the image display device (50) are all located on the optical axis; From the object side to the image source side, the front lens group (10) comprises a first meniscus positive lens (11) with positive focal power, a meniscus negative lens (12) with negative focal power, a biconcave negative lens (13) with negative focal power, a second meniscus positive lens (14) with positive focal power, and a first plano-convex positive lens (15) with positive focal power, which are arranged in sequence; From the object side to the image source side, the rear lens group (30) includes a cemented negative lens (31) with negative focal power, a third meniscus positive lens (32) with positive focal power, a second plano-convex positive lens (33) with positive focal power, and a biconvex positive lens (34) with positive focal power, which are arranged in sequence; wherein the cemented negative lens (31) is composed of a first lens and a second lens cemented together; Specifically, the lens combination of the front lens group (10) is used to control the direction of light to improve the lens resolution; the cemented negative lens (31) in the rear lens group (30) is used to correct phase difference.

2. The DLP three-dimensional scanning lens according to claim 1, characterized in that: The first lens of the cemented negative lens (31) is a biconcave negative lens, and the second lens is a biconvex positive lens.

3. The DLP three-dimensional scanning lens according to claim 2, characterized in that: The double convex positive lens side of the cemented negative lens (31) faces the image source side.

4. The DLP 3D scanning lens according to claim 1, wherein: The object side surface and the image source side surface of the first meniscus positive lens (11) have curvature radii of 16.088 to 17.782 mm and 56.73 to 62.702 mm, respectively; the object side surface and the image source side surface of the meniscus negative lens (12) have curvature radii of 23.522 to 25.998 mm and 9.58 to 10.588 mm, respectively; the object side surface and the image source side surface of the double concave negative lens (13) have curvature radii of -44.898 to -40.622 mm and 14.393 to 15.909 mm, respectively; the object side surface and the image source side surface of the second meniscus positive lens (14) have curvature radii of -46.028 to -41.644 mm and -24.523 to -22.187 mm, respectively; the object side surface and the image source side surface of the first plano-convex positive lens (15) have curvature radii of 17.326 to 19.15 mm and are infinite, respectively; As described, the curvature radius of the aperture (20) is infinite; The object side surface of the cemented negative lens (31) has a curvature radius of -12.774 to -11.557 mm, the curvature radius of the cemented surface of the first lens and the second lens is 24.544 to 27.128 mm, and the curvature radius of the image source side surface is -14.028 to -12.692 mm; the curvature radii of the object side surface and the image source surface of the third meniscus positive lens (32) are respectively -79.496 to -71.925 mm and -23.256 to -21.0416 mm; the curvature radii of the object side surface and the image source surface of the second plano-convex positive lens (33) are respectively infinite and -63.116 to -57.105; the curvature radii of the object side surface and the image source surface of the biconvex positive lens (34) are respectively 32.227 to 35.619 mm and -64.514 to -58.37 mm; The infinite radius of curvature means that the curvature of the surface is 0, that is, the surface is a plane.

5. The DLP 3D scanning lens according to claim 1, wherein: The center thickness of the first meniscus positive lens (11) on the optical axis is 6.423-7.099 mm, and the air gap between the first meniscus negative lens (11) and the meniscus negative lens (12) on the optical axis is 0.914-1.01 mm; the center thickness of the meniscus negative lens (12) on the optical axis is 1.937-2.141 mm, and the air gap between the first meniscus negative lens (11) and the biconcave negative lens (13) on the optical axis is 3.556-3.93 mm; the center thickness of the biconcave negative lens (13) on the optical axis is 1.14-1.26 mm, and the air gap between the first meniscus positive lens (11) and the meniscus negative lens (12) on the optical axis is 0.914-1.01 mm. The air gap between the second meniscus positive lens (14) and the lens on the optical axis is 1.949 to 2.155 mm; the center thickness of the second meniscus positive lens (14) on the optical axis is 2.835 to 3.133 mm, and the air gap between the second meniscus positive lens (14) and the first plano-convex positive lens (15) on the optical axis is 3.029 to 3.347 mm; the center thickness of the first plano-convex positive lens (15) on the optical axis is 4.82 to 5.328 mm, and the air gap between the first plano-convex positive lens (15) and the lens on the optical axis is 4.875 to 5.389 mm; The air gap between the aperture (20) and the cemented negative lens (31) on the optical axis is 5.874 to 6.492 mm; The center thickness of the first lens of the cemented negative lens (31) on the optical axis is 1.14-1.26 mm, the center thickness of the second lens on the optical axis is 4.304-4.758 mm, the air gap between the second lens and the third meniscus positive lens (32) on the optical axis is 0.218-0.24 mm; the center thickness of the third meniscus positive lens (32) on the optical axis is 2.817-3.113 mm, and the air gap between the second lens and the third meniscus positive lens (32) on the optical axis is 0.218-0.24 mm. 3) has an air gap of 0.498 to 0.55 mm; the center thickness of the second plano-convex positive lens (33) on the optical axis is 2.103 to 2.325 mm, and the air gap between the second plano-convex positive lens (33) and the biconvex positive lens (34) on the optical axis is 0.568 to 0.628 mm; the center thickness of the biconvex positive lens (34) on the optical axis is 3.77 to 4.166 mm, and the air gap between the second plano-convex positive lens (33) and the prism (40) on the optical axis is 6.175 to 6.825 mm; The center thickness of the prism (40) on the optical axis is 17.575-19.425 mm, and the air gap between the prism (40) and the image display device (50) on the optical axis is 0.95-0.105 mm; the center thickness of the substrate of the image display device (50) on the optical axis is 0.618-0.682 mm, and the air gap between the substrate and the micro mirror of the image display device (50) on the optical axis is 0.286-0.316 mm.

6. The DLP 3D scanning lens according to claim 1, wherein: The refractive index of the first meniscus positive lens (11) is 1.682 to 1.859; the refractive index of the meniscus negative lens (12) is 1.682 to 1.859; the refractive index of the double concave negative lens (13) is 1.758 to 1.943; the refractive index of the second meniscus positive lens (14) is 1.615 to 1.785; the refractive index of the first plano-convex positive lens (15) is 1.758 to 1.943; The refractive index of the first lens of the cemented negative lens (31) is 1.72 to 1.901, and the refractive index of the second lens is 1.416 to 1.565; the refractive index of the third meniscus positive lens (32) is 1.416 to 1.565; the refractive index of the second plano-convex positive lens (33) is 1.644 to 1.817; and the refractive index of the biconvex positive lens (34) is 1.682 to 1.

859. The refractive index of the equivalent prism (40) is 1.539 to 1.701; the refractive index of the image display device (50) is 1.444 to 1.

596.

7. The DLP 3D scanning lens according to claim 1, wherein: The Abbe number of the first meniscus positive lens (11) is 47.12 to 52.08; the Abbe number of the meniscus negative lens (12) is 47.12 to 52.08; the Abbe number of the double concave negative lens (13) is 22.61 to 24.99; the Abbe number of the second meniscus positive lens (14) is 28.595 to 31.605; and the Abbe number of the first plano-convex positive lens (15) is 22.61 to 24.

99. The Abbe number of the first lens of the cemented negative lens (31) is 24.225-26.775, and the Abbe number of the second lens is 66.88-73.92; the Abbe number of the third meniscus positive lens (32) is 66.88-73.92; the Abbe number of the second plano-convex positive lens (33) is 48.545-53.655; and the Abbe number of the biconvex positive lens (34) is 47.12-52.08; The Abbe number of the equivalent prism (40) is 57.38 to 63.42; the Abbe number of the image display device (50) is 60.99 to 67.

41.

8. The DLP three-dimensional scanning lens according to claim 1, wherein: The semi-diameters of the object side surface and the image source side surface of the first meniscus positive lens (11) are 13.063-14.438 mm and 12.35-13.65 mm respectively; the semi-diameters of the object side surface and the image source side surface of the meniscus negative lens (12) are 10.45-11.55 mm and 6.926-7.655 mm respectively; the semi-diameters of the object side surface and the image source side surface of the double concave negative lens (13) are 6.926-7.655 mm and 6.318-6.983 mm respectively; the semi-diameters of the object side surface and the image source side surface of the second meniscus positive lens (14) are 6.365-7.035 mm and 8.075-8.925 mm respectively; the semi-diameters of the object side surface and the image source side surface of the first plano-convex positive lens (15) are 8.075-8.925 mm and 8.075-8.925 mm respectively; The semi-diameter of the aperture (20) is 3.551-3.925 mm; The semi-diameter of the object side surface of the cemented negative lens (31) is 5.225-5.775 mm, the semi-diameter of the cemented surface of the first lens and the second lens is 7.125-7.875 mm, and the semi-diameter of the image source side surface is 7.125-7.875 mm; the semi-diameters of the object side surface and the image source surface of the third meniscus positive lens (32) are 8.075-8.925 mm and 9.5-10.5 mm respectively; the semi-diameters of the object side surface and the image source surface of the second plano-convex positive lens (33) are 10.45-11.55 mm and 10.45-11.55 mm respectively; the semi-diameters of the object side surface and the image source surface of the biconvex positive lens (34) are 10.45-11.55 mm and 10.45-11.55 mm respectively; The semi-diameters of the object side surface and the image source surface of the prism (40) are 8.227-9.093 mm and 6.037-6.673 mm, respectively; the semi-diameters of the object side surface and the image source surface of the image display device (50) are 5.842-6.456 mm and 5.767-6.374 mm, respectively; and the semi-diameter of the micro mirror surface of the image display device (50) is 5.71-6.311 mm; The semi-diameter refers to half of the outer diameter of the lens.

9. The DLP three-dimensional scanning lens according to claim 1, wherein: The image display device (50) can be any one of DMD, LCD, LCOS and the like.

10. The DLP three-dimensional scanning lens according to any one of claims 1 to 9, characterized in that: The working distance of the DLP three-dimensional scanning lens is: WD=630~770mm; the projection ratio is: TR=1.82; and the aperture size is: F / #=2.4.

Images