Projection optical system and electronic device
By combining positive and negative power lenses in a projection optical system, aberrations and spherical aberrations are eliminated, the field of view is expanded, and the distortion and chromatic aberration problems of projection optical systems are solved, achieving high-quality imaging.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 深圳市冰晟光电科技有限公司
- Filing Date
- 2025-05-29
- Publication Date
- 2026-05-29
Smart Images
Figure CN224303930U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical technology, and in particular to a projection optical system and electronic device. Background Technology
[0002] In the field of optical imaging, projectors 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] In related technologies, when designing a projection system for a projection lamp, a wide-angle lens, such as a fisheye lens, is usually used to give the projection lens a large projection angle in narrow spaces.
[0004] However, the optical projection systems in related technologies suffer from severe distortion and low image quality. Utility Model Content
[0005] Therefore, it is necessary to provide a projection optical system and electronic device that can reduce system distortion and improve the imaging quality of the projection optical system, addressing the aforementioned technical problems.
[0006] In a first aspect, this application provides a projection optical system, which includes, from the light-emitting side to the light-incident side, the following components:
[0007] A first lens with positive optical power;
[0008] A negative lens group with negative optical power; a negative lens group consists of multiple lenses with negative optical power;
[0009] A second lens with positive optical power;
[0010] A first cemented lens with positive optical power;
[0011] A second cemented lens with positive optical power;
[0012] A third lens with positive optical power;
[0013] Both the first and second cemented lenses include a sub-lens with positive optical power and a sub-lens with negative optical power.
[0014] In one embodiment, the first lens is a positive meniscus lens, and the incident surface of the first lens is concave, while the emitting surface of the first lens is convex; and / or,
[0015] The negative lens group includes three negative meniscus lenses, each with a concave incident surface and a convex exit surface; and / or,
[0016] The incident surface of the second lens is convex.
[0017] In one embodiment, the light-incident surface and the light-exit surface of the first cemented lens are different curved surfaces, and the light-incident surface and the light-exit surface of the second cemented lens are different curved surfaces.
[0018] In one embodiment, the light-incident surface of the first cemented lens is concave and the light-outcident surface is convex; or, the light-incident surface of the first cemented lens is convex and the light-outcident surface is concave; and
[0019] The light-incident surface of the second cemented lens is convex and the light-outcident surface is concave, or the light-incident surface of the second cemented lens is concave and the light-outcident surface is convex.
[0020] In one embodiment, both the light-emitting surface and the light-receiving surface of the third lens are convex.
[0021] In one embodiment, the ratio of the focal length of the rear lens group of the projection optics system to the focal length of the projection optics system is greater than 1.8; the rear lens group includes a first cemented lens, a second cemented lens, and a third lens.
[0022] In one embodiment, the refractive index of the first lens is greater than 1.6 and the dispersion coefficient is greater than 35.
[0023] The refractive index of the second lens is less than 1.65, and the dispersion coefficient is greater than 50.
[0024] The third lens has a refractive index greater than 1.5 and a dispersion coefficient greater than 30.
[0025] In one embodiment, the negative lens group includes a first negative meniscus lens, a second negative meniscus lens, and a third negative meniscus lens;
[0026] The first cemented lens includes a first sub-lens with positive optical power and a second sub-lens with negative optical power; the second cemented lens includes a third sub-lens with positive optical power and a fourth sub-lens with negative optical power.
[0027] In one embodiment, the first negative meniscus lens has a refractive index greater than 1.68 and a dispersion coefficient greater than 30.
[0028] The first negative meniscus lens has a refractive index greater than 1.6 and a dispersion coefficient greater than 35.
[0029] The first negative meniscus lens has a refractive index greater than 1.5 and a dispersion coefficient greater than 40.
[0030] The first sub-lens has a refractive index greater than 1.6 and a dispersion coefficient greater than 40.
[0031] The refractive index of the second sub-lens is greater than 1.5, and the dispersion coefficient is less than 45.
[0032] The refractive index of the third sub-lens is less than 1.75, and the dispersion coefficient is greater than 35.
[0033] The fourth sub-lens has a refractive index greater than 1.65 and a dispersion coefficient greater than 42.
[0034] Secondly, this application also provides an electronic device including a projection optical system according to any of the embodiments of the first aspect described above.
[0035] The aforementioned projection optical system and electronic device, wherein the projection optical system comprises, from the light-emitting side to the light-receiving side, the following components in sequence: a first lens with positive optical power; a negative lens group with negative optical power; the negative lens group comprising multiple lenses with negative optical power; a second lens with positive optical power; a first cemented lens with positive optical power; a second cemented lens with positive optical power; a third lens with positive optical power; and both the first cemented lens and the second cemented lens comprising sub-lenses with positive optical power and sub-lenses with negative optical power. Thus, by combining two cemented lenses and a third lens, the rear lens group of the projection optical system is obtained. The third lens converges light rays, while the first and second cemented lenses focus light rays of different wavelengths to eliminate spherical aberration and reduce projection distortion of the projection optical system at wide viewing angles. By combining positive and negative lens groups of different optical powers, the front lens group of the projection optical system is obtained. The combination of lens groups of different optical powers eliminates aberrations. The negative lens group composed of multiple negative lenses expands the field of view layer by layer, supporting the projection optical system to support a large projection angle in narrow spaces. In summary, the projection optical system provided by the embodiments of this application can support a large projection angle with small distortion, thereby improving the projection imaging quality. Attached Figure Description
[0036] 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.
[0037] Figure 1 This is a schematic diagram of the architecture of a projection optics system in one embodiment;
[0038] Figure 2 This is a schematic diagram of the uniformity curve of a projection optical system in one embodiment.
[0039] Figure 3 This is a schematic diagram of astigmatism and distortion of a projection optical system in one embodiment;
[0040] Figure 4 This is a schematic diagram of grid distortion in a projection optics system in one embodiment;
[0041] Figure 5 This is a schematic diagram of the chromatic aberration curve of a projection optical system in one embodiment.
[0042] Explanation of reference numerals in the attached figures:
[0043] 01: Projection optical system; 100: First lens;
[0044] 200: Negative lens group; 201: First negative meniscus lens;
[0045] 202: Second negative meniscus lens; 203: Third negative meniscus lens;
[0046] 300: Second lens; 400: Aperture stop;
[0047] 500: First cemented lens; 501: First sub-lens;
[0048] 502: Second sub-lens; 600: Second cemented lens;
[0049] 601: Third sub-lens; 602: Fourth sub-lens;
[0050] 700: Third lens; 800: Image generator. Detailed Implementation
[0051] 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.
[0052] 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.
[0053] 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.
[0054] In the field of optical imaging, projectors 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.
[0055] In related technologies, traditional wide-angle projection lenses, such as fisheye lenses, while having a large field of view, suffer from severe distortion (>15%) and significant edge illumination attenuation, making them unsuitable for the projection lamp industry. Furthermore, traditional wide-angle lenses suffer from insufficient chromatic aberration correction, resulting in color separation and fringing at the edges during white light projection, leading to low image quality. Therefore, this application provides a projection optical system that, through the combination of multiple standard spherical lenses, expands the field of view, achieves chromatic aberration correction, and ensures the image quality of the projection optical system.
[0056] Please see Figure 1 , Figure 1 The diagram shows the structure of the projection optical system 01, which, from the light-emitting side to the light-receiving side, includes: a first lens 100 with positive optical power; a negative lens group 200 with negative optical power; the negative lens group 200 includes multiple lenses with negative optical power; a second lens 300 with positive optical power; a first cemented lens 500 with positive optical power; a second cemented lens 600 with positive optical power; and a third lens 700 with positive optical power. Both the first cemented lens 500 and the second cemented lens 600 include sub-lenses with positive optical power and sub-lenses with negative optical power.
[0057] 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 800, a projection lens, and a color processing device to form an image and project it onto a screen. In this embodiment, the structure of the projection lens in the projection optics system 01 is described. The function of the projection optics system 01 is to process the light beam emitted from the light source and project it onto the screen to form a clear pattern.
[0058] Figure 1 In the projection optical system 01, the light beam projected onto the screen is from the light-emitting side, and the light beam emitted by the light source (image generator 800) is from the light-receiving side. The projection optical system 01 includes multiple sets of lenses and an aperture 400. The lens between the light-emitting side and the aperture 400 forms the front lens group, and the lens between the aperture 400 and the light-receiving side forms the rear lens group.
[0059] The front lens group includes: a first lens 100 with positive optical power, a negative lens group 200, and a second lens 300 with positive optical power. The first lens 100 can be a biconvex lens, a plano-convex lens, or a concave-convex lens (meniscus). The negative lens group 200 includes multiple negative lenses. Figure 1 The negative lens group 200 is illustrated by including three negative lenses. Any one of the negative lenses in the negative lens group 200 can be a biconcave lens, a plano-concave lens, or a concave-convex lens (meniscus lens); the second lens 300 can be a biconvex lens, a plano-convex lens, or a concave-convex lens (meniscus lens).
[0060] The rear lens group includes: a first cemented lens 500 with positive optical power, a second cemented lens 600 with positive optical power, and a third lens 700 with positive optical power. It should be noted that, based on the fact that all cemented lenses include sub-lenses with positive and negative optical power, the first cemented lens 500 can be a first cemented doublet or a multi-cemented lens, such as a cemented triplet including two positive lenses and one negative lens. Similarly, the second cemented lens 600 can be a second cemented doublet or a multi-cemented lens, such as a cemented triplet including two positive lenses and one negative lens.
[0061] In actual projection scenarios, the light generated by the image generator 800 is relatively diffuse and cannot be directly projected onto the screen. Therefore, it is necessary to first converge the light generated by the image generator 800 before projection. In this embodiment, the third lens 700 in the rear lens group, as the lens closest to the image generator 800 in the optical projection system, refers to a convex lens with positive optical power, used to converge the light generated by the image generator 800.
[0062] In the projection optical system 01, the light generated by the image generator 800 enters the third lens 700, where the incident light is converged. The converged light (including light of different wavelengths) then passes through the air medium sequentially to the second cemented lens 600 and the first cemented lens 500. The two cemented lenses focus the light of different wavelengths to correct chromatic aberration. Then, the aperture 400 further restricts the range and focal length of the light emitted from the first cemented lens 500, reducing aberrations and improving image contrast and clarity. Furthermore, the second lens 300 converts the light processed by the aperture 400 into parallel light, achieving collimation of the point light source. The light emitted from the second lens 300 is then diffused in multiple stages by multiple negative lenses in the negative lens group 200. Finally, the first lens 100 converges the diffused light emitted from the negative lens group 200 to reduce spherical aberration, presenting an inverted and magnified image on the screen, thus improving the projection imaging quality.
[0063] In one embodiment, both the light-emitting surface and the light-receiving surface of the third lens 700 are convex. That is, the third lens 700 is a biconvex lens. The light generated by the image generator 800 is refracted twice by the two convex surfaces of the biconvex lens, concentrating the incident light within a controllable range so that more light can be projected onto the screen, thereby improving the light energy utilization and image quality of the projection system.
[0064] In addition, all lenses in the projection optical system 01 are standard spherical lenses to reduce the difficulty of lens processing, reduce the production cost of the projection optical system 01, and facilitate the mass production of the projection optical system 01.
[0065] In this embodiment, from the light-emitting side to the light-receiving side, the lens comprises: a first lens 100 with positive optical power; a negative lens group 200 with negative optical power; the negative lens group 200 includes multiple lenses with negative optical power; a second lens 300 with positive optical power; a first cemented lens 500 with positive optical power; a second cemented lens 600 with positive optical power; and a third lens 700 with positive optical power. Both the first cemented lens 500 and the second cemented lens 600 include sub-lenses with positive optical power and sub-lenses with negative optical power. Thus, by combining two cemented lenses and a third lens 700, the rear lens group of the projection optical system 01 is obtained. The third lens 700 converges light rays, and the first and second cemented lenses focus light rays of different wavelengths to eliminate spherical aberration and reduce projection distortion of the projection optical system 01 at wide viewing angles. By combining positive lenses and negative lens groups 200 of different optical powers, the front lens group of the projection optical system 01 is obtained. Aberrations are eliminated by combining lens groups of different optical powers. The negative lens group composed of multiple negative lenses expands the field of view layer by layer, enabling the projection optical system 01 to support a large projection angle in narrow spaces. In summary, the projection optical system 01 provided by the embodiments of this application can support a large projection angle with small distortion, thereby improving the projection imaging quality.
[0066] As can be seen from the foregoing embodiments, both the first lens 100 and the second lens 300 are convex lenses, and the negative lens group 200 includes multiple concave lenses, but there is no limitation on the specific types. Based on this, the types of the first lens 100, the negative lens group 200, and the second lens 300 will be further explained below through an embodiment.
[0067] Please continue reading. Figure 1 The first lens 100 is a positive meniscus lens, and the light-incident surface of the first lens 100 is concave, and the light-exit surface of the first lens 100 is convex; and / or, the negative lens group 200 includes three negative meniscus lenses, and the light-incident surface of each negative lens is concave, and the light-exit surface of each negative meniscus lens is convex; and / or, the light-incident surface of the second lens 300 is convex.
[0068] The first lens 100 is a positive meniscus lens, with its concave surface facing the aperture stop 400. The negative lens group 200 sequentially includes a first negative meniscus lens 201, a second negative meniscus lens 202, and a third negative meniscus lens 203, with the concave surfaces of all three lenses facing the aperture stop 400. The second lens 300 has its convex surface facing the aperture stop 400 and can be a positive meniscus lens, a concave-convex lens, or a biconvex lens. Light rays enter through the convex surface of the second lens 300, undergoing two refractions to correct aberrations. The combination of the first negative meniscus lens 201, the second negative meniscus lens 202, and the third negative meniscus lens 203 increases the focal length, achieving light diffusion. Finally, the positive meniscus lens converges the light rays emitted from the third negative meniscus lens 203, reducing spherical aberration.
[0069] Optionally, the first lens 100 is a positive meniscus lens, with its concave surface facing the aperture stop 400; in the negative lens group 200, the radii of curvature of the first negative meniscus lens 201, the second negative meniscus lens 202, and the third negative meniscus lens 203 become smaller and smaller; the second lens 300 is a plano-convex lens, with its convex surface facing the aperture stop 400.
[0070] Optionally, the first lens 100 is a positive meniscus lens, with its concave surface facing the aperture stop 400; in the negative lens group 200, the radii of curvature of the first negative meniscus lens 201, the second negative meniscus lens 202, and the third negative meniscus lens 203 become smaller and smaller; the second lens 300 is a positive meniscus lens, with its convex surface facing the aperture stop 400.
[0071] Optionally, the first lens 100 is a positive meniscus lens, with its concave surface facing the aperture stop 400; in the negative lens group 200, the radii of curvature of the first negative meniscus lens 201, the second negative meniscus lens 202, and the third negative meniscus lens 203 become progressively smaller; and the second lens 300 is a biconvex lens.
[0072] In this embodiment, a lens combination of "positive meniscus + three negative meniscus" is used. First, the light is diverged by a negative meniscus lens, and then converged by a positive meniscus lens to cover a wider angular range and expand the field of view. Furthermore, the spherical aberration produced by the positive lens and the negative lens can cancel each other out to some extent. Using a combination of positive and negative meniscus lenses can also eliminate spherical aberration to a certain degree.
[0073] In one embodiment, the light-incident surface and the light-exit surface of the first cemented lens 500 are different curved surfaces, and the light-incident surface and the light-exit surface of the second cemented lens 600 are different curved surfaces.
[0074] Both the first cemented lens 500 and the second cemented lens 600 include a positive lens and a negative lens. Thus, by combining the positive and negative lens groups 200, spherical aberration and chromatic aberration can be corrected on the one hand, and the number of "air-lens" interfaces can be reduced on the other hand, thereby reducing light reflection loss.
[0075] In this embodiment, there are no restrictions on the type and number of lenses in the first cemented lens 500 and the second cemented lens 600. The cementing process of the lenses in the first cemented lens 500 and the second cemented lens 600 can be carried out by using optical grade adhesives, or they can be directly bonded by relying on the molecular attraction of the polished surface to form cemented lenses.
[0076] In an exemplary embodiment, the first cemented lens 500 is a first cemented doublet lens, and the light-incident surface of the first cemented lens 500 is a plane and the light-outcident surface is a convex surface; or, the light-incident surface of the first cemented lens 500 is a concave surface and the light-outcident surface is a convex surface; or, the light-incident surface of the first cemented lens 500 is a convex surface and the light-outcident surface is a concave surface; or, the light-incident surface of the first cemented lens 500 is a convex surface and the light-outcident surface is a plane.
[0077] In an exemplary embodiment, the second cemented lens 600 is a second cemented lens, and the light-incident surface of the second cemented lens 600 is a plane and the light-outcident surface is a convex surface; or, the light-incident surface of the second cemented lens 600 is a concave surface and the light-outcident surface is a convex surface; or, the light-incident surface of the second cemented lens 600 is a convex surface and the light-outcident surface is a concave surface; or, the light-incident surface of the second cemented lens 600 is a convex surface and the light-outcident surface is a plane.
[0078] In another embodiment, the light-incident surface and the light-exit surface of the first cemented lens 500 are both convex; the light-incident surface and the light-exit surface of the second cemented lens 600 are both convex.
[0079] In another embodiment, the light-incident surface of the first cemented lens 500 is concave, and the light-exit surface is convex; both the light-incident and light-exit surfaces of the second cemented lens 600 are convex. The incident light undergoes at least two refractions through the second cemented lens to obtain converging light. Then, the converging light is diverged by the concave light-incident surface of the first cemented lens 500, and the diverged light is then converged again by the convex light-exit surface of the first cemented lens 500. This allows light rays from different apertures to converge to the same point as much as possible, thereby improving image quality.
[0080] In this embodiment, the light-incident surface and the light-exit surface of the first cemented lens 500 are different curved surfaces, and the light-incident surface and the light-exit surface of the second cemented lens 600 are different curved surfaces. This is equivalent to not restricting the order of the positive and negative lenses in the first cemented lens 500 and the second cemented lens 600. While ensuring the projection quality of the projection optical system 01, it improves the flexibility of the lens combination in the projection optical system 01 and enriches the production process of the projection optical system 01.
[0081] In one embodiment, the light-incident surface of the first cemented lens 500 is concave and the light-outcident surface is convex, or the light-incident surface of the first cemented lens 500 is convex and the light-outcident surface is concave; and the light-incident surface of the second cemented lens 600 is convex and the light-outcident surface is concave, or the light-incident surface of the second cemented lens 600 is concave and the light-outcident surface is convex.
[0082] Optionally, the first cemented lens 500 is a first cemented doublet lens, which includes a plano-convex lens and a plano-concave lens sequentially from the light-emitting side to the light-receiving side. In this case, the light-receiving surface and the light-emitting surface of the first cemented doublet lens are as follows: Figure 1 As shown, the incident surface is concave and the exit surface is convex. The second cemented lens 600 is a second cemented doublet, which includes a negative meniscus lens and a positive meniscus lens sequentially from the exit side to the incident side. In this case, the incident surface of the second cemented doublet is convex and the exit surface is concave.
[0083] Optionally, the first cemented lens 500 is a first cemented doublet lens, comprising a plano-convex lens and a plano-concave lens sequentially from the light-emitting side to the light-receiving side. The light-receiving surface of the first cemented doublet lens is concave, and the light-emitting surface is convex. The second cemented lens 600 is a second cemented doublet lens, comprising a biconvex lens and a biconcave lens sequentially from the light-emitting side to the light-receiving side. In this case, the light-receiving surface of the second cemented lens 600 is concave, and the light-emitting surface is convex.
[0084] Optionally, the first cemented lens 500 is a first cemented doublet, comprising a plano-concave lens and a plano-convex lens sequentially from the light-emitting side to the light-receiving side. The light-receiving surface of the first cemented doublet is convex, and the light-emitting surface is concave. The second cemented lens 600 is a second cemented doublet, comprising a biconvex lens and a negative meniscus lens. In this case, the light-receiving surface of the second cemented lens 600 is concave, and the light-emitting surface is convex.
[0085] Optionally, the first cemented lens 500 is a first cemented doublet, comprising a plano-concave lens and a plano-convex lens sequentially from the light-emitting side to the light-receiving side. The light-receiving surface of the first cemented doublet is convex, and the light-emitting surface is concave. The second cemented lens 600 is a second cemented doublet, comprising a negative meniscus lens and a positive meniscus lens sequentially from the light-emitting side to the light-receiving side. In this case, the light-receiving surface of the second cemented doublet is convex, and the light-emitting surface is concave.
[0086] In this embodiment, the light-incident and light-out surfaces of the first cemented lens 500 and the second cemented lens 600 are not limited, thereby improving the flexibility of the lens combination in the projection optical system 01 while ensuring the projection quality of the projection optical system 01.
[0087] The foregoing embodiments have described the lens type and imaging principle in the projection optical system 01. Next, the component parameters in the projection optical system 01, such as the system focal length, lens refractive index, and dispersion coefficient, will be described.
[0088] In one embodiment, the ratio of the focal length of the rear lens group of the projection optical system 01 to the focal length of the projection optical system 01 is greater than 1.8; the rear lens group includes a first cemented lens 500, a second cemented lens 600, and a third lens 700.
[0089] Focal length is a quantitative indicator that measures the convergence or divergence of light; it refers to the distance between the focal point of a lens and the optical center of the lens. A smaller focal length results in a wider field of view, but may introduce distortion; a larger focal length results in a narrower angle of view and a sharper image. Based on these characteristics, the focal length of a lens can be adjusted according to the application scenario to achieve a balanced adjustment of the lens's imaging effect and field of view.
[0090] The focal length of the subsequent lens group is The focal length of projection optical system 01 is Indication, calculation A larger ratio indicates a relatively longer focal length for the rear lens group and a relatively shorter overall focal length for the projection optical system 01. This fully leverages the characteristic of short-focal-length projection systems to project larger images from shorter distances, maximizing the projection size within a limited space, making it suitable for space-constrained environments. Furthermore, because the overall focal length of the system is relatively short, the field of view of the projection optical system 01 increases accordingly, while keeping the imaging chip size and other conditions constant. This allows for coverage of a larger projection area, enabling the presentation of a wider image on the screen and enhancing the projection experience. In this embodiment of the application, The ratio is greater than 1.8, and can be 1.9, 2.0, 2.1, etc., to balance the aberrations of the projection optical system 01 with the system length.
[0091] In one embodiment, the first lens 100 has a refractive index greater than 1.6 and a dispersion coefficient greater than 35; the second lens 300 has a refractive index less than 1.65 and a dispersion coefficient greater than 50; and the third lens 700 has a refractive index greater than 1.5 and a dispersion coefficient greater than 30.
[0092] The refractive index characterizes the degree of refraction of light as it propagates through a lens and the lens's ability to influence light. A higher refractive index results in greater refraction of light within the lens. In this embodiment, the first lens 100, the second lens 300, and the third lens 700 are all positive lenses, and their refractive indices reflect their ability to converge light. Specifically, the first lens 100 and the third lens 700 serve as two edge lenses corresponding to the lens group 01 of the projection optical system, requiring strong light-converging capabilities. Correspondingly, the refractive index of the first lens 100 is greater than 1.6, for example, 1.7 or 1.8; and the refractive index of the third lens 700 is greater than 1.5, for example, 1.57 or 1.6. Furthermore, the rear lens group refracts the emitted light to the optical elements of the negative lens group 200 through the aperture 400 and the second lens 300. Since the rear lens group as a whole can be compared to a convex lens that converges light, it is equivalent to already converging the light. Therefore, for the second lens 300, there is no need to excessively converge the light. In this embodiment, the refractive index of the second lens 300 is less than 1.65, for example, 1.6 or 1.49.
[0093] The dispersion coefficient characterizes the dispersion properties of a lens material for different colors of light. A smaller dispersion coefficient indicates a smaller difference in refractive index for different wavelengths of light, resulting in less noticeable dispersion of different colors of light after passing through the lens, less chromatic aberration during imaging, and a clearer image. Conversely, a larger dispersion coefficient indicates a greater difference in refractive index for different colors of light, leading to more pronounced dispersion and potential issues such as colored edges or blurring during imaging. In this embodiment, the first lens 100 has a dispersion coefficient greater than 35, for example, 40 or 46; the second lens 300 has a dispersion coefficient greater than 50, for example, 60 or 70; and the third lens 700 has a dispersion coefficient greater than 30, for example, 35 or 40. This embodiment provides data references for the design of the first lens 100, second lens 300, and third lens 700 in the projection optical system 01, based on both the refractive index and dispersion coefficient of the lenses.
[0094] In one embodiment, the negative lens group 200 includes a first negative meniscus lens 201, a second negative meniscus lens 202, and a third negative meniscus lens 203; the first cemented lens 500 includes a first sub-lens 501 with positive optical power and a second sub-lens 502 with negative optical power; and the second cemented lens 600 includes a third sub-lens 601 with positive optical power and a fourth sub-lens 602 with negative optical power.
[0095] In the negative lens group 200, the radius of curvature of the first negative meniscus lens 201 is greater than that of the second negative meniscus lens 202, and the radius of curvature of the second negative meniscus lens 202 is greater than that of the third negative meniscus lens 203. The first cemented lens 500 is a cemented doublet lens, which includes a first sub-lens 501 (positive meniscus lens) and a second sub-lens 502 (plano-concave lens) from the light-emitting side to the light-receiving side. The first cemented lens 500 is a cemented doublet lens, which includes a third sub-lens 601 (biconvex lens) and a fourth sub-lens 602 (negative meniscus lens) from the light-emitting side to the light-receiving side.
[0096] In this embodiment, the types and quantities of lenses in the three lens combinations—negative lens group 200, first cemented lens 500, and second cemented lens 600—are further restricted to ensure lens consistency during mass production of the combined lens. Next, the range of refractive index and dispersion coefficient values for each lens in the combined lens is explained: In one embodiment, the refractive index of the first negative meniscus lens 201 is greater than 1.68, and the dispersion coefficient is greater than 30; the refractive index of the first negative meniscus lens 201 is greater than 1.6, and the dispersion coefficient is greater than 35; the refractive index of the first negative meniscus lens 201 is greater than 1.5, and the dispersion coefficient is greater than 40; the refractive index of the first sub-lens 501 is greater than 1.6, and the dispersion coefficient is greater than 40; the refractive index of the second sub-lens 502 is greater than 1.5, and the dispersion coefficient is less than 45; the refractive index of the third sub-lens 601 is less than 1.75, and the dispersion coefficient is greater than 35; the refractive index of the fourth sub-lens 602 is greater than 1.65, and the dispersion coefficient is greater than 42.
[0097] In this embodiment, data references are provided for the design of each lens in the three types of lens combinations in the projection optical system 01, namely the negative lens group 200, the first cemented lens 500, and the second cemented lens 600, from the two dimensions of the refractive index and dispersion coefficient of the lens. This is to standardize the design and assembly logic of each lens in the projection optical system 01, and at the same time improve the projection quality of the projection optical system 01.
[0098] In one embodiment, a projection optical system is provided, comprising, from the light-emitting side to the light-incident side: a positive meniscus lens (concave surface facing the aperture stop); a negative meniscus lens (concave surface facing the aperture stop); a negative meniscus lens (concave surface facing the aperture stop); a negative meniscus lens (concave surface facing the aperture stop); a plano-convex lens (convex surface facing the aperture stop); a first cemented doublet lens, comprising a plano-convex lens (convex surface facing the aperture stop) and a plano-concave lens (concave surface being the light-incident surface); a second cemented doublet lens, comprising a biconvex lens and a negative meniscus lens; and a biconvex lens.
[0099] Table 1 shows the lens parameter information of each lens in the projection optical system of 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 1-19 represent the surface numbers of the optical elements arranged sequentially from the light-emitting side to the light-receiving side of the projection optical system. Among them, the radius of curvature represents 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.
[0100] Table 1
[0101]
[0102] It should be emphasized that the lens parameters in Table 1 above are only one example of parameters in the projection optical system 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.
[0103] Furthermore, to verify the imaging quality of the projection optical system provided in the embodiments of this application, a uniformity comparison experiment, astigmatism and distortion map experiment, grid distortion experiment and chromatic aberration comparison experiment were conducted using the projection optical system built with the parameters in Table 1 above.
[0104] Please see Figure 2 , Figure 2 This is a schematic diagram of the uniformity curve of a projection optical system. Figure 2 In the diagram, the horizontal axis represents the field of view angle (°), and the vertical axis represents uniformity. From... Figure 2 It can be seen that the illuminance uniformity of the projection optical system provided in this application embodiment is >80% (center to edge).
[0105] Please see Figure 3 , Figure 3 This is a schematic diagram of astigmatism and distortion in a projection optical system. Figure 3 Figure (a) shows a schematic diagram of aberrations for light rays of different wavelengths. The horizontal axis represents the distance aberration (mm) between the meridional and sagittal beam image points on the optical axis, and the vertical axis represents the field of view (°). Figure (b) shows a distortion diagram, with the horizontal axis representing the distortion rate (%) and the vertical axis representing the field of view (°). From Figure 3 It can be seen that the distortion of the projection optical system provided in this application embodiment is <2%. Please refer to [link / reference]. Figure 4 , Figure 4 This is a schematic diagram of grid distortion in a projection optical system. Figure 4 It can be seen that when imaging the grid, the image is relatively complete and the distortion is small.
[0106] Please see Figure 5 , Figure 5 This is a schematic diagram of the chromatic aberration curve of a projection optical system. Figure 5 In the diagram, the vertical axis represents the field of view (°), and the horizontal axis represents the chromatic difference (nm). Figure 5 It can be seen that the projection optical system provided in the embodiments of this application... (C / F light) <15nm. The experimental data above show that the projection optical system provided in this application has the following characteristics: field of view: 90° (diagonal); distortion: <2%; illuminance uniformity: >80% (center to edge); chromatic aberration: Δλ (C / F light) <15nm. This reduces system distortion and improves the imaging quality of the projection optical system, making it widely applicable in the field of projection lamps. Furthermore, the standard spherical lens in the projection optical system provided in this application further reduces processing difficulty and saves production costs.
[0107] This application also provides an electronic device including the aforementioned projection optical system. The electronic device further includes a light source, the light beam provided by which passes sequentially through a third lens, a second cemented lens, a first cemented lens, a second lens, a negative lens group, and a first lens, and is finally projected onto a corresponding position to form a projection pattern. This application combines two cemented lenses and a third lens to obtain the rear lens group of the projection optical system. Utilizing the chromatic aberration correction capability of the cemented lenses, it reduces projection distortion of the projection optical system at wide viewing angles; by combining the positive and negative lens groups, it expands the field of view, enabling the projection optical system to support a large projection angle in narrow spaces and improving image quality.
[0108] 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.
[0109] 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 optical system, characterized in that, The projection optical system comprises, from the light-emitting side to the light-incident side, the following: A first lens with positive optical power; A negative lens group with negative optical power; the negative lens group comprises multiple lenses with negative optical power; A second lens with positive optical power; A first cemented lens with positive optical power; A second cemented lens with positive optical power; A third lens with positive optical power; Both the first cemented lens and the second cemented lens include a sub-lens with positive optical power and a sub-lens with negative optical power.
2. The projection optical system according to claim 1, characterized in that, The first lens is a positive meniscus lens, and the incident surface of the first lens is concave, while the emitting surface of the first lens is convex; and / or, The negative lens group includes three negative meniscus lenses, and the incident surface of each negative lens is concave, and the exit surface of each negative meniscus lens is convex; and / or, The light-incident surface of the second lens is convex.
3. The projection optical system according to claim 1 or 2, characterized in that, The light-incident surface and the light-exit surface of the first cemented lens are different curved surfaces, and the light-incident surface and the light-exit surface of the second cemented lens are different curved surfaces.
4. The projection optical system according to claim 3, characterized in that, The first cemented lens has a concave incident surface and a convex exit surface, or the first cemented lens has a convex incident surface and a concave exit surface; and... The light-incident surface of the second cemented lens is convex and the light-outcident surface is concave, or the light-incident surface of the second cemented lens is concave and the light-outcident surface is convex.
5. The projection optical system according to claim 1 or 2, characterized in that, Both the light-emitting surface and the light-receiving surface of the third lens are convex.
6. The projection optical system according to claim 1 or 2, characterized in that, The ratio of the focal length of the rear lens group of the projection optical system to the focal length of the projection optical system is greater than 1.8; the rear lens group includes the first cemented lens, the second cemented lens, and the third lens.
7. The projection optical system according to claim 1 or 2, characterized in that, The first lens has a refractive index greater than 1.6 and a dispersion coefficient greater than 35. The refractive index of the second lens is less than 1.65, and the dispersion coefficient is greater than 50. The third lens has a refractive index greater than 1.5 and a dispersion coefficient greater than 30.
8. The projection optical system according to claim 1 or 2, characterized in that, The negative lens group includes a first negative meniscus lens, a second negative meniscus lens, and a third negative meniscus lens; The first cemented lens includes a first sub-lens with positive optical power and a second sub-lens with negative optical power; the second cemented lens includes a third sub-lens with positive optical power and a fourth sub-lens with negative optical power.
9. The projection optical system according to claim 8, characterized in that, The first negative meniscus lens has a refractive index greater than 1.68 and a dispersion coefficient greater than 30. The first negative meniscus lens has a refractive index greater than 1.6 and a dispersion coefficient greater than 35. The first negative meniscus lens has a refractive index greater than 1.5 and a dispersion coefficient greater than 40. The first sub-lens has a refractive index greater than 1.6 and a dispersion coefficient greater than 40. The refractive index of the second sub-lens is greater than 1.5, and the dispersion coefficient is less than 45. The refractive index of the third sub-lens is less than 1.75, and the dispersion coefficient is greater than 35. The fourth sub-lens has a refractive index greater than 1.65 and a dispersion coefficient greater than 42.
10. An electronic device, characterized in that, Includes the projection optical system as described in any one of claims 1-9.