Projection lenses, projection optics systems and electronic devices

Abstract

This application relates to a projection lens, a projection optical system, and an electronic device. The projection lens includes: a first lens group with negative optical power, a second lens group with positive optical power, and a third lens group with positive optical power; the first, second, and third lens groups are arranged sequentially along the optical axis from the light-emitting side to the light-receiving side; the first and second lens groups are movably disposed within a groove along the optical axis, used to adjust the focal length of the projection lens by adjusting the distance between the first and second lens groups; the third lens is fixedly disposed within the groove and has the ability to move bidirectionally within a preset range along the optical axis to adjust the focus of the projection lens. This method can achieve high-magnification zoom while maintaining the overall quality of the projected image, while also simplifying the projection lens structure and saving costs.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to a projection lens, a projection optical system, and an electronic device. Background Technology

[0002] In the field of optical imaging, projection lenses use the principle of rectilinear propagation of light to form high-resolution images and text on a projection surface, and are widely used in various fields.

[0003] When a projection lens is fixed in place, the projection distance must be precisely calibrated. If the installation position is off or the projection distance changes (such as switching between short-throw and long-throw lenses), it can easily lead to problems such as blurred images and increased color difference. In related technologies, the projection image quality is usually improved through complex multi-lens linkage or electronic correction compensation, but this has the problems of complex projection lens structure and high cost. Utility Model Content

[0004] Therefore, it is necessary to provide a projection lens, projection optical system, and electronic device to address the aforementioned technical problems, which can simplify the projection lens structure and save costs.

[0005] In a first aspect, this application provides a projection lens, which includes a first lens group with negative optical power, a second lens group with positive optical power, and a third lens group with positive optical power; the first lens group, the second lens group, and the third lens group are arranged sequentially along the light-emitting side to the light-incident side of the optical axis.

[0006] The first and second lens groups are movably disposed in a groove along the optical axis, and are used to adjust the focal length of the projection lens by adjusting the distance between the first and second lens groups; the third lens is fixedly disposed in the groove and has the ability to move bidirectionally within a preset range along the optical axis, so as to adjust the focus of the projection lens.

[0007] In one embodiment, the light-incident surface of the first lens group is concave, and the light-exiting surface is concave; the light-incident surface of the second lens group is any one of concave, planar, or convex, and the light-exiting surface is convex; the light-incident surface of the third lens group is any one of concave, planar, or convex, and the light-exiting surface is convex.

[0008] In one embodiment, the first lens group includes a first cemented lens, and the first cemented lens is provided with a first biconcave lens and a positive meniscus lens in sequence along the light-emitting side to the light-incident side of the optical axis.

[0009] In one embodiment, the second lens group includes a first positive lens, a second cemented lens, and a second positive lens;

[0010] The light-incident surface of the first positive lens is any one of concave, planar, or convex surfaces, and the light-outceasing surface is convex.

[0011] The light-incident surface of the second cemented lens is concave, and the light-outceasing surface is convex.

[0012] The incident surface of the second positive lens can be any one of concave, flat, or convex, and the exit surface is convex.

[0013] In one embodiment, the second cemented lens is provided with a biconvex lens and a second biconcave lens in sequence along the light-emitting side to the light-incident side of the optical axis.

[0014] In one embodiment, the third lens group includes a third positive lens.

[0015] In one embodiment, the third lens group moves within a groove of -5mm to 5mm.

[0016] In one embodiment, during projection by the projection lens, the movement distance of the third lens group in the groove is adapted to the spacing between the first lens group and the second lens group.

[0017] Secondly, this application also provides a projection optical system, including: a light source, a collimating device, a film device, and a projection lens according to any embodiment of the first aspect, wherein the light source, collimating device, film device, and projection lens are arranged sequentially at the same level.

[0018] Thirdly, this application also provides an electronic device, including the projection optical system of the second aspect.

[0019] The aforementioned projection lens, projection optical system, and electronic device include a projection lens comprising a first lens group with negative optical power, a second lens group with positive optical power, and a third lens group with positive optical power. The first, second, and third lens groups are arranged sequentially along the optical axis from the light-emitting side to the light-receiving side. The first and second lens groups are movably disposed within a groove along the optical axis, used to adjust the focal length of the projection lens by adjusting the distance between the first and second lens groups. The third lens is fixedly disposed within the groove and has the ability to move bidirectionally within a preset range along the optical axis to adjust the focal point of the projection lens. In the projection lens, the beam angle of light is converted sequentially through the third, second, and first lens groups to achieve projection. During projection, the focal point of the projection lens is adjusted by the axial movement of the third lens group within the groove to achieve focusing and ensure the clarity of the projected image. The axial movement of the first and second lens groups adjusts the distance between them, thereby adjusting the focal length of the projection lens and increasing the lens magnification. In summary, the lens in this embodiment can achieve high-magnification zoom while maintaining good chromatic aberration correction, low distortion, and excellent image uniformity, thereby improving the overall quality of the projected image. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the projection lens architecture in one embodiment;

[0022] Figure 2 This is a schematic diagram of the projection lens architecture in another embodiment;

[0023] Figure 3 This is a schematic diagram of the projection lens architecture in another embodiment;

[0024] Figure 4 This is a schematic diagram of the projection lens architecture in another embodiment;

[0025] Figure 5 This is a schematic diagram of the uniformity curve of the projection lens in one embodiment;

[0026] Figure 6 This is a schematic diagram of the uniformity curve of the projection lens in another embodiment;

[0027] Figure 7 This is a schematic diagram of the uniformity curve of the projection lens in another embodiment;

[0028] Figure 8a This is a schematic diagram of astigmatism of a projection lens in one embodiment;

[0029] Figure 8b This is a schematic diagram of the distortion of the projection lens in one embodiment;

[0030] Figure 9a This is a schematic diagram of astigmatism of the projection lens in another embodiment;

[0031] Figure 9b This is a schematic diagram of the distortion of the projection lens in another embodiment;

[0032] Figure 10a This is a schematic diagram of astigmatism of the projection lens in another embodiment;

[0033] Figure 10b This is a schematic diagram of the distortion of the projection lens in another embodiment;

[0034] Figure 11 This is a schematic diagram of the grid distortion of the projection lens in one embodiment;

[0035] Figure 12 This is a schematic diagram of the grid distortion of the projection lens in another embodiment;

[0036] Figure 13 This is a schematic diagram of the grid distortion of the projection lens in another embodiment;

[0037] Figure 14 This is a schematic diagram of the chromatic aberration curve of a projection optical system in one embodiment;

[0038] Figure 15 This is a schematic diagram of the chromatic aberration curve of the projection optics system in another embodiment;

[0039] Figure 16 This is a schematic diagram of the chromatic aberration curve of the projection optics system in another embodiment.

[0040] Explanation of reference numerals in the attached figures:

[0041] 01: Projection lens; 100: First lens group;

[0042] 101: First biconcave lens; 102: Positive meniscus lens;

[0043] 200: Second lens group; 201: First positive lens;

[0044] 202: Biconvex lens; 203: Second biconcave lens;

[0045] 204: Second positive lens; 300: Third lens group. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0047] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application, are intended to cover non-exclusive inclusion. In the description of embodiments of this application, "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. "A plurality of" and "multiple" mean two or more, unless otherwise expressly specified. References to "embodiment" herein mean that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments of this application, the technical terms "length," "width," "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction relationship between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0049] In the field of projection imaging, zoom projection lenses require precise calibration of the projection distance when fixedly installed. If the installation position is off or the projection distance changes (such as switching between short-throw and long-throw lenses), it can easily lead to blurred images and increased color difference. Related technologies typically use complex multi-lens linkage or electronic correction compensation, but these suffer from structural complexity and high cost.

[0050] Furthermore, when achieving wide field-of-view projection, projection lenses often face issues such as color difference, distortion, and image uniformity. These issues affect the quality of the projected image, especially in environments requiring high-quality projection, such as commercial displays, home theaters, and professional presentations.

[0051] In summary, due to the complexity of optical design and the difficulty of aberration control, the zoom ratio of lenses in related technologies is usually limited to no more than 2 times (such as 20°-40° or 15°-30°), making it difficult to meet the needs of both wide-angle and telephoto scenarios. If the magnification is forcibly increased, the following problems will occur: (1) severe color difference and distortion when projecting at a large field of view, affecting the image quality; (2) the complex structure and high cost of zoom lenses make it difficult to simultaneously achieve both optical performance and cost-effectiveness; (3) poor uniformity of the projection lens leads to inconsistent brightness of the projected image.

[0052] Based on the above-mentioned technical problems, this application provides a projection lens, a projection optical system, and an electronic device. By moving the three sets of lens groups axially, optical compensation is achieved while simplifying the structure, solving the problems of image plane shift and aberration deterioration caused by changes in projection distance, improving projection quality, and enhancing optical performance.

[0053] Please see Figure 1 , Figure 1 The diagram shows the structure of the projection lens 01, which includes a first lens group 100 with negative optical power, a second lens group 200 with positive optical power, and a third lens group 300 with positive optical power. The first lens group 100, the second lens group 200, and the third lens group 300 are arranged sequentially along the light-emitting side to the light-incident side of the optical axis.

[0054] The first lens group 100 and the second lens group 200 are movably disposed in a groove along the optical axis, and are used to adjust the focal length of the projection lens 01 by adjusting the distance between the first lens group 100 and the second lens group 200; the third lens is fixedly disposed in the groove and has the ability to move bidirectionally within a preset range along the optical axis, so as to adjust the focus of the projection lens 01.

[0055] In the field of projection optics, a light beam emitted from a light source undergoes a series of processing steps by optical components such as an image generator and a projection lens 01 to form an image and project it onto a screen. In this embodiment, the structure of the projection lens 01 is described. The function of the projection lens 01 is to process the light beam emitted from the light source and project it onto the screen to form a projected pattern.

[0056] Figure 1In this embodiment, the incident light beam is the beam projected from the light source onto the film, and the emitting light beam is the beam projected onto the screen. Along the optical axis from the incident light side to the emitting light side, a third lens group 300, a second lens group 200, and a first lens group 100 are sequentially arranged. These three lens groups sequentially diverge the beam angle of the incident light to form parallel light, thereby achieving beam projection. In this embodiment, the third lens group 300 has positive optical power. By adjusting the distance between the third lens group 300 and the film, and between the third lens group 300 and the second lens group 200, the beam angle on the incident light side is diverged. The second lens group 200 also has positive optical power. By adjusting the distance between the second lens group 200 and the first lens group 100, and between the second lens group 200 and the third lens group 300, the beam angle emitted by the third lens is diverged. The first lens group 100 has negative optical power and is used to diverge the beam angle of the second lens group 200 to form parallel light for projection.

[0057] In practical applications, the first lens group 100, the second lens group 200, and the third lens group 300 are all disposed within a sliding groove. Figure 1 The groove is not shown in the figure. By adjusting the position of different lens groups in the groove, the projection lens 01 can be zoomed or focused.

[0058] Using the groove as a cam groove, each lens group corresponds to a cam. By rotating the cam corresponding to each lens group, each lens group can move axially within the groove, thereby changing the position of the lens group within the groove and achieving zooming or focusing of the projection lens 01.

[0059] It should be noted that the projection process can be divided into two main steps: zooming and focusing. Zooming refers to adjusting the focal length of the lens, which aims to adjust the field of view of the projection lens 01 to suit different projection distances. Focusing refers to adjusting the focal point of the projection lens 01, which aims to adjust the image plane of the projection lens 01 to ensure clear imaging. Since changes in projection distance during the projection process of the projection lens 01 will cause image plane shift, it means that when the projection distance changes or the image is not clear, it is usually necessary to perform the zooming and focusing steps in sequence.

[0060] In the actual projection process, focusing is achieved by moving the third lens group 300 to the position of the groove, and by moving the first lens group 100 and the second lens group 200 to the position of the groove, the distance between the first lens group 100 and the second lens group 200 is adjusted to achieve zoom.

[0061] Optionally, the projection process can be a process of focusing first and zooming later. The implementation method is as follows: First, according to the projection distance, move the third lens group 300 along the optical axis to adjust the image plane position and ensure image clarity and color difference stability. Then, keep the position of the third lens group 300 fixed and move the first lens group 100 and the second lens group 200. By adjusting the distance between the first lens group 100 and the second lens group 200, the total focal length of the projection lens 01 is dynamically adjusted.

[0062] Optionally, the projection process can be a process of zooming first and focusing later. The implementation method is as follows: first, adjust and move the first lens group 100 and the second lens group 200 according to the preset field of view. By adjusting the distance between the first lens group 100 and the second lens group 200, and then keeping the positions of the first lens group 100 and the second lens group 200 fixed, move the third lens group 300 along the optical axis to adjust the image plane position and ensure image clarity and color difference stability.

[0063] In one exemplary embodiment, the third lens group 300 moves within a groove range of -5mm to 5mm.

[0064] It should be noted that the movement range is set based on the initial position of the third lens group 300 in the groove, and the direction of the groove (i.e., the direction of movement) matches the direction of the optical axis. During actual movement, the initial position of the third lens group 300 can be used as the starting point to flexibly select the direction and distance of movement, depending on the desired image sharpness. For example, the third lens group 300 can be moved 5mm along the direction from the light-incident side to the light-outcident side, for example, by moving 1mm, 2mm, 3mm, 4mm, or 5mm; or the initial position of the third lens group 300 can be used as the starting point to move 5mm along the direction from the light-outcident side to the light-incident side, for example, by moving 1mm, 2mm, 3mm, 4mm, or 5mm. This flexible movement of the third lens group 300 within the groove can compensate for image plane displacement caused by changes in projection distance, ensuring image sharpness.

[0065] It should be emphasized that during the projection process of the projection lens 01, the third lens group 300 moves independently for focusing, and the movement range of the third lens group 300 in the groove is preset; while the first lens group 100 and the second lens group 200 work together for focusing. That is, in the actual projection process, only the distance between the first lens group 100 and the second lens group 200 needs to be set, and the movement range of the first lens group 100 and the second lens group 200 in the groove is not restricted.

[0066] In an exemplary embodiment, when projecting through the projection lens 01, the moving distance of the third lens group 300 in the groove is adapted to the distance between the first lens group 100 and the second lens group 200.

[0067] The movement distance of the third lens group 300 in the groove refers to the absolute value of the distance between the position of the third lens group 300 after movement and its initial position, which is a positive number not less than 0. In this embodiment, the movement distance of the third lens group 300 in the groove can be negatively correlated with the distance between the first lens group 100 and the second lens group 200. That is, the smaller the movement distance of the third lens group 300 in the groove, the larger the distance between the first lens group 100 and the second lens group 200; the larger the movement distance of the third lens group 300 in the groove, the smaller the distance between the first lens group 100 and the second lens group 200.

[0068] In this embodiment, the moving distance of the third lens group 300 in the groove is adapted to the distance between the first lens group 100 and the second lens group 200, so that after focusing with the third lens group 300, the distance between the first lens group 100 and the second lens group 200 can be quickly adjusted to achieve zoom, or after adjusting the distance between the first lens group 100 and the second lens group 200 to achieve zoom, the third lens group 300 can be quickly adjusted to focus, thereby improving projection efficiency.

[0069] In this embodiment, the projection lens 01 includes a first lens group 100 with negative optical power, a second lens group 200 with positive optical power, and a third lens group 300 with positive optical power. The first lens group 100, the second lens group 200, and the third lens group 300 are arranged sequentially along the optical axis from the light-emitting side to the light-incident side. The first lens group 100 and the second lens group 200 are movably disposed in a groove along the optical axis, and are used to adjust the focal length of the projection lens 01 by adjusting the distance between the first lens group 100 and the second lens group 200. The third lens is fixedly disposed in the groove and has the ability to move bidirectionally within a preset range along the optical axis, so as to adjust the focal point of the projection lens 01. In the projection lens 01, the beam angle of light is converted sequentially through the third lens group 300, the second lens group 200, and the first lens group 100 to achieve projection. During projection, the focal point of the projection lens 01 is adjusted by the axial movement of the third lens group 300 within the groove, ensuring focus and the clarity of the projected image. The axial movement of the first lens group 100 and the second lens group 200 adjusts the distance between them, thereby adjusting the focal length of the projection lens 01 and increasing the lens magnification. In summary, the lens in this embodiment can achieve high-magnification zoom while maintaining good chromatic aberration correction, low distortion, and excellent image uniformity, thus improving the overall quality of the projected image.

[0070] Next, we will explain the surface structure of the light-incident and light-exit surfaces of each lens group in the projection lens 01 in the scenario where light is emitted from the light-incident side, generated into outgoing light through the projection lens 01, and projected onto the screen.

[0071] Please continue reading. Figure 1 The light-incident surface of the first lens group 100 is concave, and the light-exit surface is concave; the light-incident surface of the second lens group 200 is any one of concave, planar, or convex, and the light-exit surface is convex; the light-incident surface of the third lens group 300 is any one of concave, planar, or convex, and the light-exit surface is convex.

[0072] In practical applications, when the light-incident surface and the light-exit surface of the first lens group 100 are both concave, the second lens group 200 and the third lens group 300 can be combined in at least the following ways: (1) The light-incident surface of the second lens group 200 is concave and the light-exit surface is convex, and the light-incident surface of the third lens group 300 is concave and the light-exit surface is convex; (2) The light-incident surface of the second lens group 200 is concave and the light-exit surface is convex, and the light-incident surface of the third lens group 300 is planar and the light-exit surface is convex; (3) The light-incident surface of the second lens group 200 is concave and the light-exit surface is convex, and the light-incident surface and the light-exit surface of the third lens group 300 are both convex; (4) The light-incident surface of the second lens group 200 is planar and the light-exit surface is convex, and the light-incident surface of the third lens group 300 is concave. (5) The light-incident surface of the second lens group 200 is a plane and the light-outcident surface is a convex surface, and the light-incident surface of the third lens group 300 is a plane and the light-outcident surface is a convex surface; (6) The light-incident surface of the second lens group 200 is a plane and the light-outcident surface is a convex surface, and the light-incident surface of the third lens group 300 is a convex surface and the light-outcident surface is a convex surface; (7) The light-incident surface of the second lens group 200 is a convex surface and the light-outcident surface is a convex surface, and the light-incident surface of the third lens group 300 is a concave surface and the light-outcident surface is a convex surface; (8) The light-incident surface of the second lens group 200 is a convex surface and the light-outcident surface is a convex surface, and the light-incident surface of the third lens group 300 is a plane and the light-outcident surface is a convex surface; (9) The light-incident surface of the second lens group 200 is a convex surface and the light-outcident surface is a convex surface, and the light-incident surface of the third lens group 300 is a convex surface and the light-outcident surface is a convex surface.

[0073] Figure 1 In the diagram, the light-incident surface of the first lens group 100 is concave, and the light-exiting surface is concave; the light-incident surface of the second lens group 200 is concave, and the light-exiting surface is convex; and the light-incident surface of the third lens group 300 is concave, and the light-exiting surface is convex.

[0074] Light emitted from the incident light side enters the third lens group 300 through the concave surface and exits through the convex surface, which is equivalent to the mirror in the third lens group 300 refracting the light at least twice. Then, the light emitted from the third lens group 300 enters the second lens group 200 through the concave surface and exits through the convex surface, which is equivalent to the mirror in the second lens group 200 refracting the light at least twice. Then, the two concave surfaces of the third lens group 300 diverge the light emitted from the second lens group 200 again, outputting parallel light.

[0075] It should be emphasized that, for any lens group, provided that the incident and exit surfaces meet the above requirements, there are no restrictions on the number or type of lenses in the lens group. For example, the first lens group 100 can be a biconcave lens, a lens group composed of two plano-concave lenses cemented together, or a lens group composed of a positive lens and a negative lens cemented together; the second lens group 200 can be a positive meniscus lens, or a lens group composed of multiple positive and negative lenses; the second lens group 200 can be a positive meniscus lens, or a lens group composed of multiple positive and negative lenses.

[0076] In this embodiment, the light emitted from the incident light side is refracted multiple times sequentially by the third lens group 300, the second lens group 200, and the first lens group 100 to achieve flexible changes in the beam angle, thereby meeting the projection requirements of different distances in different scenarios.

[0077] Next, the lens structures of the first lens group 100, the second lens group 200, and the third lens group 300 of the projection lens 01 in the aforementioned embodiments will be described respectively.

[0078] In an exemplary embodiment, the first lens group 100 includes a first cemented lens, and the first cemented lens is provided with a first biconcave lens 101 and a positive meniscus lens 102 in sequence along the light-emitting side to the light-incident side of the optical axis.

[0079] Cemented lenses refer to lens assemblies that use a bonding process to bond at least two lenses together. This bonding can be done using optical-grade adhesives or by directly bonding them together using the molecular attraction of polished surfaces.

[0080] In the projection lens 01, the first cemented lens can be a cemented doublet lens that cements together mirrors with different refractive indices, including a first biconcave lens 101 and a positive meniscus lens 102, wherein the light-incident surface of the positive meniscus lens 102, i.e. the light-incident surface of the first lens group 100, is a concave surface; and the light-exiting surface of the first cemented doublet lens, i.e. the light-exiting surface of the first lens group 100, is a concave surface.

[0081] Furthermore, the first lens group 100 is used to bear the main optical power. To reduce chromatic aberration, the lenses in the first lens group can be made of high refractive index materials and relatively low dispersion materials (because a high refractive index is required, only relatively low dispersion materials can be used). For example, the first biconcave lens 101 has a refractive index nd>1.6 and a dispersion coefficient vd>35; the positive meniscus lens 102 has a refractive index nd>1.68 and a dispersion coefficient vd<35.

[0082] In this embodiment, a first cemented lens is used as the first lens group 100. By cementing the optical lenses together, the number of air-glass interfaces can be reduced, thereby reducing light energy loss. This makes the structure of the first cemented lens more compact and stable. Furthermore, by using materials with different refractive indices for cementation, light of different wavelengths can be focused at the same focal point, improving image quality.

[0083] In an exemplary embodiment, the second lens group 200 includes a first positive lens 201, a second cemented lens, and a second positive lens 204; the light-incident surface of the first positive lens 201 is any one of a concave surface, a flat surface, or a convex surface, and the light-exiting surface is a convex surface; the light-incident surface of the second cemented lens is a concave surface, and the light-exiting surface is a convex surface; the light-incident surface of the second positive lens 204 is any one of a concave surface, a flat surface, or a convex surface, and the light-exiting surface is a convex surface.

[0084] In practical applications, based on the fact that the light-incident surface of the second cemented lens is concave and the light-outceasing surface is convex, the light-incident and light-outceasing surfaces of the first positive lens 201 and the second positive lens 204 in the second lens group 200 include at least the following situations: (1) The light-incident surface of the first positive lens 201 is concave and the light-outceasing surface is convex, and the light-incident surface of the second positive lens 204 is concave and the light-outceasing surface is convex; (2) The light-incident surface of the first positive lens 201 is concave and the light-outceasing surface is convex, and the light-incident surface of the second positive lens 204 is flat and the light-outceasing surface is convex; (3) The light-incident surface of the first positive lens 201 is concave and the light-outceasing surface is convex, and the light-incident surface of the second positive lens 204 is convex and the light-outceasing surface is convex; (4) The light-incident surface of the first positive lens 201 is flat and the light-outceasing surface is convex, and the light-incident and light-outceasing surfaces of the second positive lens 204 are both concave and convex; (5) The light-incident surface of the first positive lens 201 is a plane and the light-outcident surface is a convex surface, and the light-incident surface of the second positive lens 204 is a plane and the light-outcident surface is a convex surface; (6) The light-incident surface of the first positive lens 201 is a plane and the light-outcident surface is a convex surface, and the light-incident surface of the second positive lens 204 is a convex surface and the light-outcident surface is a convex surface; (7) The light-incident surface of the first positive lens 201 is a plane and the light-outcident surface is a convex surface. (8) The light-incident surface of the first positive lens 201 is convex, the light-outcident surface is convex, and the light-incident surface of the second positive lens 204 is concave, and the light-outcident surface is convex; (9) The light-incident surface of the first positive lens 201 is convex, the light-outcident surface is convex, and the light-incident surface of the second positive lens 204 is flat, and the light-outcident surface is convex;

[0085] Figure 1 The light-incident surface of the first positive lens 201 is concave and the light-outceasing surface is convex; the light-incident surface of the second cemented lens is concave and the light-outceasing surface is convex; the light-incident surface of the second positive lens 204 is concave and the light-outceasing surface is convex.

[0086] It should be emphasized that, based on the premise that the light-emitting surface of the first positive lens 201 is convex, there is no restriction on the type of the first positive lens 201. For example, the first positive lens 201 can be a biconvex lens, such as... Figure 1 As shown, in this case, both the incident and emitting surfaces of the first positive lens 201 are convex. In another scenario, the first positive lens 201 can also be a plano-convex lens, meaning the incident surface of the first positive lens 201 is planar and the emitting surface is convex. In yet another scenario, the first positive lens 201 can also be a positive meniscus lens, meaning the incident surface of the positive meniscus lens is concave and the emitting surface is convex.

[0087] Based on the premise that the light-incident surface of the second cemented lens is concave and the light-outceasing surface is convex, there are no restrictions on the number of lenses or the type of each lens in the second cemented lens. For example, the second cemented lens can be a cemented doublet lens or a cemented triplet lens, etc.

[0088] Taking the second cemented lens as an example of a cemented doublet lens, in one exemplary embodiment, the second cemented lens is provided with a biconvex lens 202 and a biconcave lens 203 sequentially arranged along the light-emitting side to the light-receiving side of the optical axis. In this case, the light-receiving surface of the second biconcave lens 203 is the same as the light-receiving surface of the second cemented lens, and the light-receiving surface of the biconvex lens 202 is the same as the light-receiving surface of the second cemented lens, and the light-receiving surface is convex. In this way, cementing the biconvex lens 202 and the biconcave lens 203 together reduces light energy loss and makes the structure of the second cemented lens more compact.

[0089] In the second lens group 200, the first positive lens 201 and the biconvex lens 202 in the second cemented lens are made of lenses with higher refractive index and lower dispersion, while the second biconcave lens in the second cemented lens is made of lenses with high dispersion and high refractive index. For example, the refractive index nd of the first positive lens 201 is >1.6, and the dispersion coefficient vd is >35; the refractive index nd of the biconvex lens 202 is >1.55, and the dispersion coefficient vd is >40; the refractive index nd of the second biconcave lens 203 is >1.65, and the dispersion coefficient vd is <35; the refractive index nd of the second positive lens 204 is >1.60, and the dispersion coefficient is not limited, for example, the dispersion coefficient vd is <40.

[0090] In this embodiment, a second lens group 200 is obtained by combining a first positive lens 201 with different optical powers and different types of second cemented lenses and second positive lenses 204. Through the synergistic effect of multi-level aberration correction, flexible optical path control, and compact structural design, a balance is achieved between imaging accuracy, system adaptability, and stability. It is suitable for imaging scenarios of complex optical systems with high requirements for image quality, size, and functional diversity.

[0091] In one exemplary embodiment, the third lens group 300 includes a third positive lens. Figure 1The third positive lens is used as a schematic diagram of a positive meniscus lens. The concave surface of the third positive meniscus lens is used as the light-incident surface, and the convex surface is used as the light-outceasing surface. The light beam is "expanded" through the diverging effect of the concave surface and then converged through the convex surface, so as to achieve more flexible focusing control.

[0092] In one specific embodiment, a projection lens 01 is provided. The projection lens 01 is divided into three lens groups, including seven spherical lenses, which, along the direction from the light-emitting side to the light-incident side of the optical axis, sequentially include:

[0093] Negative lens group: includes a cemented lens comprising a negative lens (e.g., a biconcave lens) and a positive lens (e.g., a positive meniscus lens).

[0094] The first positive lens group consists of four lenses, which can be a cemented lens consisting of a positive lens (e.g., a biconvex lens), a positive lens (e.g., a biconvex lens), and a negative lens (e.g., a biconcave lens), or a positive lens (e.g., a positive meniscus lens).

[0095] The second positive lens group includes a positive lens (e.g., a positive meniscus lens).

[0096] The parameters of each lens are as follows: First lens: refractive index nd>1.60, dispersion coefficient vd>35; Second lens: refractive index nd>1.68, dispersion coefficient vd>30; Third lens: refractive index nd>1.60, dispersion coefficient vd>35; Fourth lens: refractive index nd>1.55, dispersion coefficient vd>40; Fifth lens: refractive index nd>1.65, dispersion coefficient vd<35; Sixth lens: refractive index nd>1.60, dispersion coefficient not limited; Seventh lens: refractive index nd>1.65, dispersion coefficient not limited.

[0097] Table 1 shows the lens parameters of each lens in this embodiment, namely, radius of curvature (mm), spacing (mm), refractive index nd, dispersion coefficient vd, and light transmission radius (mm). In Table 1, surface numbers 1-12 represent the surface numbers of the optical elements arranged sequentially from the light-emitting side to the light-receiving side. The radius of curvature indicates the degree of curvature of the corresponding surface, and the spacing represents the distance along the optical axis from the corresponding surface to the next adjacent surface.

[0098] Table 1

[0099]

[0100] D1 represents the distance between the light-incident surface of the second lens and the light-outceasing surface of the third lens, which is the distance between the third group of lenses and the second group of lenses. D2 represents the distance between the light-incident surface of the sixth lens and the light-outceasing surface of the seventh lens, which is the distance between the second group of lenses and the first group of lenses.

[0101] The values ​​of D1 and D2 are shown in Table 2 for different field of view angles. Table 2 shows the parameter information of the projection lens under different field of view angles.

[0102] Table 2

[0103]

[0104] It should be emphasized that the lens parameters in Tables 1 and 2 above are only one parameter illustration of the projection optical system in the embodiments of this application. In actual applications, the radius of curvature, spacing, glass refractive index, and dispersion coefficient of each lens can be adjusted according to the actual application scenario.

[0105] In this embodiment, during the zoom phase, the negative lens group and the first positive lens group are moved. Through the coordinated operation of the negative lens group and the first positive lens group, the focal length is changed, thereby achieving the zoom function and adjusting the field of view (16°-40°). During the focusing phase, a dynamic compensation mechanism is employed to independently move the second positive lens group (movement range ±5mm). The image plane position is adjusted according to the projection distance to compensate for image plane shift caused by changes in projection distance, ensuring image clarity and chromatic aberration stability, thus achieving the focusing function without the need for an additional focusing structure. This three-lens linkage design ensures the stability of optical performance during zooming, giving the projection lens optical characteristics such as a large zoom ratio, low distortion, high illumination uniformity, and low chromatic aberration.

[0106] Furthermore, to verify the imaging quality of the projection lens provided in the embodiments of this application, three sets of projection lenses were set up at field angles of 40°, 22.5° and 16° respectively, and four sets of experiments were conducted on each set of projection lenses for uniformity, astigmatism and distortion, grid distortion and chromatic aberration.

[0107] in, Figures 2-4 These are schematic diagrams of the three sets of projection lens structures under field of view angles of 40°, 22.5°, and 16°, respectively.

[0108] Figure 5 This is a schematic diagram of the uniformity curve corresponding to a 40° field of view. Figure 6 This is a schematic diagram of the uniformity curve corresponding to a 22.5° field of view. Figure 7 This is a schematic diagram of the uniformity curve corresponding to a 16° field of view. Figures 5-7 In the graph shown, the horizontal axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis, and the vertical axis represents the uniformity. From Figures 5-7As shown in the schematic diagram, in a scene with a field of view of 40°, the illuminance uniformity of the projection lens provided in this application embodiment is >80% (center to edge); in a scene with a field of view of 22.5°, the illuminance uniformity of the projection lens provided in this application embodiment is >90% (center to edge); and in a scene with a field of view of 16°, the illuminance uniformity of the projection lens provided in this application embodiment is >92% (center to edge).

[0109] Figure 8a This is a schematic diagram of astigmatism corresponding to different wavelengths of light under a 40° field of view. The horizontal axis represents the distance aberration (mm) between the meridional narrow beam image point and the sagittal narrow beam image point on the optical axis, and the vertical axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis. Figure 8b This is a schematic diagram showing the distortion of light at different wavelengths under a 40° field of view. The horizontal axis represents the distortion rate (%), and the vertical axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis. Figure 8a and Figure 8b As can be seen, with a field of view of 40°, the distortion of the projection lens provided in this application is less than 2%.

[0110] Figure 9a This is a schematic diagram of astigmatism corresponding to different wavelengths of light under a field of view of 22.5°. The horizontal axis represents the distance aberration (mm) between the meridional narrow beam image point and the sagittal narrow beam image point on the optical axis, and the vertical axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis. Figure 9b This is a schematic diagram showing the distortion of light at different wavelengths under a 22.5° field of view. The horizontal axis represents the distortion rate (%), and the vertical axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis. Figure 9a and Figure 9b As can be seen, with a field of view of 22.5°, the distortion of the projection lens provided in this application is less than 1%.

[0111] Figure 10a This is a schematic diagram of astigmatism corresponding to different wavelengths of light under a 16° field of view. The horizontal axis represents the distance aberration (mm) between the meridional narrow beam image point and the sagittal narrow beam image point on the optical axis, and the vertical axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis. Figure 10b This is a schematic diagram showing the distortion of light at different wavelengths under a 16° field of view. The horizontal axis represents the distortion rate (%), and the vertical axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis. Figure 10a and Figure 10b As can be seen, with a field of view of 16°, the distortion of the projection lens provided in this application is less than 1%.

[0112] Figure 11 This is a schematic diagram of the mesh distortion corresponding to a 40° field of view. Figure 12 This is a schematic diagram of the mesh distortion corresponding to a 22.5° field of view. Figure 13 This is a schematic diagram of the mesh distortion at a 16° field of view. From Figures 11-13 As can be seen from the schematic diagram, when the projection lens provided in this application image the grid, the image is relatively complete and the distortion is small.

[0113] Figure 14 This is a schematic diagram of the chromatic aberration curve corresponding to a 40° field of view. Figure 15 This is a schematic diagram of the chromatic aberration curve corresponding to a 22.5° field of view. Figure 16 This is a schematic diagram of the chromatic aberration curve corresponding to a 16° field of view. Figures 14-16 In the curve graph shown, the horizontal axis represents color difference ( The vertical axis represents the radial distance (mm) from the measurement point to the intersection of the optical axis. From... Figures 14-16 As can be seen from the schematic diagram, the chromatic aberration of the projection lens provided in the embodiments of this application is... (C / F light) <30nm.

[0114] The experimental data above demonstrate that the projection optical system provided in this application reduces field of view, distortion, illuminance uniformity, and chromatic aberration, thereby improving system distortion and image quality, and can be widely used in the field of projection lamps. Furthermore, the standard spherical lenses in the projection optical system provided in this application further reduce processing difficulty and save production costs.

[0115] Secondly, this application also provides a projection optical system, including: a light source, a collimating device, a film device, and a projection lens of any of the foregoing embodiments, wherein the light source, collimating device, film device, and projection lens are sequentially arranged at the same level. In the projection optical system, the light source provides initial light energy to generate light with specific wavelength, intensity, and beam characteristics (such as directionality and polarization state); the collimating device converts the divergent light (spherical wave) emitted by the light source into parallel light (plane wave), reducing the diffusion loss of light energy during propagation; the film device selectively blocks or modulates the phase of the incident parallel light through geometric patterns (such as circuit patterns, text, images, etc.) in the light-transmitting and light-blocking areas, loading pattern information; the projection lens projects the pattern of the film device onto a target plane (such as a photoresist coating or projection screen) through a lens system to achieve "reduced" or "scaled" imaging, and uses a simple projection lens to achieve projection imaging.

[0116] In one exemplary embodiment, this application also provides an electronic device including a projection optical system. The projection optical system provides initial light energy through a light source, generating light with specific wavelength, intensity, and beam characteristics (such as directionality and polarization state). A collimating device converts the divergent light (spherical wave) emitted by the light source into parallel light (plane wave), reducing light energy diffusion loss during propagation. A film device selectively blocks or modulates the phase of the incident parallel light through geometric patterns (such as circuit patterns, text, images, etc.) in the light-transmitting and light-blocking areas, loading pattern information. A projection lens projects the pattern from the film device onto a target plane (such as a photoresist coating or projection screen) through a lens system, achieving "reduced" or "scale-matched" imaging. In this embodiment, the electronic device can be a projector, lithography machine, smart glasses, 3D scanner, etc., suitable for different application scenarios.

[0117] Those skilled in the art will understand that Figures 1-4 The structure shown is only a block diagram of a portion of the structure related to the present application. The specific optical structure may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0118] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0119] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A projection lens, characterized in that, The projection lens includes a first lens group with negative optical power, a second lens group with positive optical power, and a third lens group with positive optical power. The first lens group, the second lens group, and the third lens group are arranged sequentially along the light-emitting side to the light-incident side of the optical axis; The first lens group and the second lens group are movably disposed in a groove along the optical axis, and are used to adjust the focal length of the projection lens by adjusting the distance between the first lens group and the second lens group; the third lens is fixedly disposed in the groove and has the ability to move bidirectionally within a preset range along the optical axis, so as to adjust the focus of the projection lens.

2. The projection lens according to claim 1, characterized in that, The first lens group has a concave light-incident surface and a concave light-outcident surface; the second lens group has a light-incident surface that is concave, planar, or convex, and a convex light-outcident surface; the third lens group has a light-incident surface that is concave, planar, or convex, and a convex light-outcident surface.

3. The projection lens according to claim 2, characterized in that, The first lens group includes a first cemented lens, and the first cemented lens is provided with a first biconcave lens and a positive meniscus lens in sequence along the light-emitting side to the light-incident side of the optical axis.

4. The projection lens according to any one of claims 1-3, characterized in that, The second lens group includes a first positive lens, a second cemented lens, and a second positive lens; The light-incident surface of the first positive lens is any one of a concave surface, a flat surface, or a convex surface, and the light-outceasing surface is a convex surface; The light-incident surface of the second cemented lens is concave, and the light-outceasing surface is convex. The light-incident surface of the second positive lens is any one of a concave surface, a flat surface, or a convex surface, and the light-outceasing surface is a convex surface.

5. The projection lens according to claim 4, characterized in that, The second cemented lens is provided with a biconvex lens and a second biconcave lens in sequence along the light-emitting side to the light-incident side of the optical axis.

6. The projection lens according to any one of claims 1-3, characterized in that, The third lens group includes a third positive lens.

7. The projection lens according to any one of claims 1-3, characterized in that, The third lens group moves within a range of -5mm to 5mm in the groove.

8. The projection lens according to any one of claims 1-3, characterized in that, When projecting through the projection lens, the movement distance of the third lens group in the groove is adapted to the distance between the first lens group and the second lens group.

9. A projection optical system, characterized in that, The projection optical system includes a light source, a collimating device, a film device, and a projection lens as described in any one of claims 1-8, wherein the light source, the collimating device, the film device, and the projection lens are arranged sequentially at the same level.

10. An electronic device, characterized in that, Includes the projection optical system as described in any one of claims 9.

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