A lens for a projector

Abstract

The utility model relates to a lens of projector in the field of lens, including mirror body, be provided with lens group in mirror body, the lens group includes first lens and second lens, first lens and second lens are fixed and installed in mirror body from imaging side to image source side in proper order, first lens and second lens are all crescent lens, the light exit side surface of first lens and second lens is recessed to the light entrance side, the light entrance side surface of first lens and second lens is convex to the direction of incident light, the light exit side and light entrance side surface of first lens and second lens are all even aspheric surface, greatly simplified lens structure, reduced lens number and mirror body length, can project the bigger picture under shorter projection distance, namely have the excellent short focus performance.

Description

Technical Field

[0001] This utility model relates to the field of lenses, and in particular to a lens for a projector. Background Technology

[0002] As an important image display device, the performance of the projector's core optical component—the lens—directly determines the quality of the projected image and the device's portability. With technological advancements, the market demands projectors that are thinner, lighter, more portable, and capable of projecting larger images. Therefore, developing lenses with simple structures, high image quality, and short-throw projection capabilities has become a crucial direction for the industry.

[0003] Currently, projector lenses on the market typically employ complex optical structures to achieve good aberration correction and imaging effects, often requiring combinations of three or more lenses, such as... Figure 1 The existing technology shown consists of three lenses: a plano-convex lens 1, a biconcave lens 3, and a biconvex lens 2, arranged sequentially from the image source side to the imaging side. This results in an increase in lens size and weight, which is detrimental to the miniaturization and lightweight design of projectors. Although this structure achieves performance requirements to a certain extent, its three-lens design still has room for simplification, and its relatively long optical length limits its application in ultra-thin, portable devices. Furthermore, its projected image size is still limited, making it difficult to project a sufficiently large image over short distances. Utility Model Content

[0004] In order to overcome the shortcomings of existing technical solutions, this utility model provides a projector lens that can effectively solve the technical problem of large overall structure and insufficient image size.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A projector lens includes a lens body, and a lens group is disposed inside the lens body. The lens group includes a first lens and a second lens. The first lens and the second lens are fixedly installed inside the lens body from the imaging side to the image source side. Both the first lens and the second lens are meniscus lenses. The light-emitting side surfaces of the first lens and the second lens are concave towards the light-incident side, and the light-incident side surfaces of the first lens and the second lens are convex towards the incident light direction. Both the light-emitting side and the light-incident side surfaces of the first lens and the second lens are even-order aspherical surfaces.

[0007] Furthermore, the thickness of the middle part of the first lens and the second lens is greater than the thickness at the edge.

[0008] Furthermore, the refractive indices Nd1 and Nd2 of both the first and second lenses are in the range of 1.45. <Nd<1.6。

[0009] Furthermore, the first and second lenses have the same refractive index.

[0010] Furthermore, the Abbe numbers Vd1 and Vd2 of both the first and second lenses are in the range of 56.5. <Vd<58.5。

[0011] Furthermore, the Abbe numbers of the first and second lenses are the same.

[0012] Furthermore, the lens body includes a lens barrel and a front cover. The lens barrel has a hollow structure, and a positioning step is provided on the image source side of the inner wall of the lens barrel. The lens group is paired and installed into the lens barrel from the imaging side of the lens barrel. The image source side edge of the lens group contacts the positioning step. The front cover is closed to the imaging side of the lens barrel, and the inner wall of the front cover presses against the imaging side edge of the lens group.

[0013] Furthermore, the outer wall of the lens barrel is provided with external threads and a lens mount, and the inner wall of the lens mount and the front cover are screwed to the lens barrel through internal threads.

[0014] Furthermore, the first and second lenses are provided with retainers.

[0015] Compared with existing technologies, the advantages of this invention are: it consists of only two meniscus lenses, the first and second lenses, which greatly simplifies the lens structure and reduces the number of lenses and the length of the lens body compared to existing solutions that require at least three lenses. This not only reduces manufacturing costs but also enables the entire lens and even the projector to be miniaturized, thinned, and lightweight, meeting the stringent portability requirements of modern consumer electronics. By employing two meniscus lenses with concave light-emitting surfaces facing the light-incident surfaces and convex light-incident surfaces facing the incident light direction, combined with an aspherical design, it can project a larger image at a shorter projection distance, thus possessing excellent short-throw performance and effectively improving the product's applicability and user experience. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the prior art;

[0017] Figure 1 Numbers: 1-Planto-convex lens, 2-Biconvex lens, 3-Biconcave lens.

[0018] Figure 2 This is a perspective view of the present utility model;

[0019] Figure 3 This is a schematic diagram of the structure of this utility model;

[0020] Figure 4 This is the optical path diagram of this utility model;

[0021] Figure 5 This is a parameter diagram of the first lens in this utility model;

[0022] Figure 6 This is a parameter diagram of the second lens in this utility model;

[0023] Figure 2-6 Number: 1-First lens, 2-Second lens, 3-Lens barrel, 301-Positioning step, 4-Front cover, 5-Lens mount, 6-LCD screen, 7-Fresnel lens, 8-Screen. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] The following is combined with Figures 2-6 A detailed description of a projector lens according to this utility model is provided:

[0026] In the description of this utility model, it should be understood that the term "imaging side" refers to the side of the lens facing the projection screen, and "image source side" refers to the side of the lens facing the display screen such as LCD or DLP. "Incident light side" and "exit light side" refer to a single lens; the surface where light first arrives is the incident light side, and the surface that leaves after refraction is the exit light side.

[0027] A projector lens includes a lens body and a lens group disposed inside the lens body. The lens group includes a first lens 1 and a second lens 2. The first lens 1 and the second lens 2 are fixedly installed inside the lens body from the imaging side to the image source side. The first lens 1 and the second lens 2 are both meniscus lenses. The light-emitting side surfaces of the first lens 1 and the second lens 2 are concave towards the light-incident side, and the light-incident side surfaces of the first lens 1 and the second lens 2 are convex towards the incident light direction. The light-emitting side and the light-incident side surfaces of the first lens 1 and the second lens 2 are both even-order aspherical surfaces.

[0028] It is composed of only two meniscus lenses, the first lens 1 and the second lens 2. Compared with the solution requiring at least three lenses in the prior art, the lens structure is greatly simplified, and the number of lenses and the length of the lens body are reduced. This not only reduces the production and manufacturing cost, but also enables the entire lens and even the entire projector to achieve miniaturization, thinning and light weight, meeting the stringent requirements of modern consumer electronics for portability. By adopting two meniscus lenses whose light-exiting side surfaces are concave toward the light-entering side and whose light-entering side surfaces are convex toward the incident light direction, and in combination with the aspheric design, the lenses can project a larger image at a shorter projection distance, that is, they have excellent short-focus performance, which effectively improves the applicable space of the product and user experience. Both the light-exiting side and light-entering side surfaces of the first lens 1 and the second lens 2 adopt even-order aspheric design, which can accurately and efficiently correct various aberrations such as spherical aberration, astigmatism, field curvature and distortion. Thus, while simplifying the structure, the high-definition, low-distortion high-quality imaging effect is ensured for both the edge and the center of the image, and a perfect balance between optical performance and structure simplification is achieved.

[0029] The first lens 1 and the second lens 2 are both made of PMMA. PMMA material has the advantages of high light transmittance, low cost, light weight and easy injection molding of aspheric surfaces, which is very suitable for large-scale production of the present solution.

[0030] The first lens 1 and the second lens 2 are assembled and connected by a holder. The central thickness of the first lens 1 and the second lens 2 is greater than the edge thickness, which ensures the structural strength of the lenses and the stability of optical performance.

[0031] Further, the refractive indices Nd1 and Nd2 of the first lens 1 and the second lens 2 both range from 1.45<Nd<1.6. Preferably, the refractive indices of the two lenses are the same, so that the required light deflection capability can be achieved by using common optical plastics, and the total length of the optical system is effectively controlled. Meanwhile, the consistent refractive index simplifies the material procurement and production process, which is conducive to quality control and cost reduction.

[0032] Further, the Abbe numbers Vd1 and Vd2 of the first lens 1 and the second lens 2 both range from 56.5<Vd<58.5, and preferably the Abbe numbers of the two lenses are the same. This effectively selects a low-dispersion material, which can significantly reduce the chromatic aberration of the lens and improve the color purity and clarity of the projected image. The consistent high Abbe number design is the key to ensuring that the two-piece lens can still obtain excellent color performance under the simplified structure

[0033] The lens body includes a lens barrel 3 and a front cover 4. The lens barrel 3 is a hollow structure, and a positioning step 301 is provided on the image source side of the inner wall of the lens barrel 3. The lens group is paired and installed into the lens barrel 3 from the imaging side, with the image source side edge of the lens group contacting the positioning step 301. The front cover 4 is closed onto the imaging side of the lens barrel 3, and the inner wall of the front cover 4 presses against the imaging side edge of the lens group. This ensures accurate positioning and stable installation of the lens group. This structure has a simple assembly process, can effectively control the relative positional accuracy between the lenses, ensures the stability and consistency of the optical system, and is also easy to disassemble and maintain.

[0034] The outer wall of the lens barrel 3 is provided with external threads and a lens mount 5. The lens mount 5 and the inner wall of the front cover 4 are screwed to the lens barrel 3 through internal threads.

[0035] This embodiment provides a lens for an ultra-short throw projector.

[0036] The lens mainly consists of a lens body and a lens group disposed within the lens body.

[0037] The lens body includes a lens barrel 3 and a front cover 4. The lens barrel 3 is a hollow cylindrical structure with one open end, and an annular positioning step 301 is machined on the image source side of its inner wall. The front cover 4 is an annular component with internal threads machined on its inner wall. The outer wall of the lens barrel 3, near the imaging side, has external threads that mate with the aforementioned internal threads, as well as a lens mount 5 for fixing the entire lens to the projector body.

[0038] The lens group consists of two lenses, a first lens 1 and a second lens 2, which are coaxially arranged within the lens barrel 3 from the imaging side to the image source side. Both the first lens 1 and the second lens 2 are meniscus lenses, and both are made of PMMA material through precision injection molding. Their common material parameters are: refractive index Nd = 1.491756, Abbe number Vd = 57.44. The thickness of both lenses in the middle is greater than their edge thickness, exhibiting a typical meniscus shape.

[0039] During installation, insert the lens assembly through the imaging side opening of the lens barrel 3, so that the edge of the second lens 2 on the image source side abuts against the positioning step 301. Screw the front cover 4 into the external thread of the lens barrel 3. By tightening the front cover 4, the inner wall of the cover presses the imaging side edge of the first lens 1, thereby firmly pressing the entire lens assembly into the lens barrel 3.

[0040] The imaging side of the first lens 1: This is the light-emitting side surface, which is concave towards the image source side.

[0041] The radius of curvature R = 23.7004 mm, and the conicity K = 0.575303.

[0042] Even-order aspheric coefficients:

[0043] A2 = 6.10692E-03;

[0044] A4 = -3.83143E-05;

[0045] A6 = 3.76488E-07;

[0046] A8 = -7.10794E-09;

[0047] A10 = 9.05394E-11;

[0048] A12 = -4.63147E-13;

[0049] A14 = 1.09530E-15;

[0050] A16 = -9.88844E-19.

[0051] Sagittal values ​​corresponding to different aperture sizes:

[0052] When the aperture is 0.00000E+00, the sagitta is 0.00000E+00;

[0053] When the aperture is 2.00000E+00, the sagitta is -6.07735E-02;

[0054] When the aperture is 4.00000E+00, the sagitta is -2.52297E-01;

[0055] When the aperture is 6.00000E+00, the sagitta is -5.99176E-01;

[0056] When the aperture is 8.00000E+00, the sagitta is -1.13337E+00;

[0057] When the aperture is 1.00000E+01, the sagitta is -1.84728E+00;

[0058] When the aperture is 1.00000E+01, the sagitta is -2.57509E+00;

[0059] Image source surface of the first lens 1: This is the incident light side surface, which bulges in the direction of incident light.

[0060] The radius of curvature R = 12.8513 mm, and the conic coefficient K = -0.717382.

[0061] Even-order aspheric coefficients:

[0062] A2 = 1.52691E-02;

[0063] A4 = -9.15033E-06;

[0064] A6 = 1.66101E-07;

[0065] A8 = -1.25705E-09;

[0066] A10 = 1.20169E-11;

[0067] A12 = 6.29305E-14;

[0068] A14 = -6.62362E-16;

[0069] A16 = 1.45001E-18.

[0070] Sagittal values ​​corresponding to different aperture sizes:

[0071] When the aperture is 0.00000E+00, the sagitta is 0.00000E+00;

[0072] When the aperture is 2.00000E+00, the sagitta is -9.49529E-02;

[0073] When the aperture is 4.00000E+00, the sagitta is -3.84250E-01;

[0074] When the aperture is 6.00000E+00, the sagitta is -8.78614E-01;

[0075] When the aperture is 8.00000E+00, the sagitta is -1.58528E+00;

[0076] When the aperture is 1.00000E+01, the sagitta is -2.46590E+00;

[0077] When the aperture is 1.00000E+01, the sagitta is -3.31085E+00.

[0078] The imaging side of the second lens 2: This is the light-emitting side surface, which is concave towards the image source side.

[0079] The radius of curvature R = 20.8664 mm, and the conic coefficient K = -9.95989e+39

[0080] Even-order aspheric coefficients:

[0081] A2 = -2.41146E-02;

[0082] A4 = 4.21324E-05;

[0083] A6 = 4.40767E-08;

[0084] A8=7.04056E-09;

[0085] A10 = -8.22675E-11;

[0086] A12 = 2.79707E-13;

[0087] A14 = 9.94755E-16;

[0088] A16 = -5.76814E-18.

[0089] Sagittal values ​​corresponding to different aperture sizes:

[0090] When the aperture is 0.00000E+00, the sagitta is 0.00000E+00;

[0091] When the aperture is 2.00000E+00, the sagitta is -9.57798E-02;

[0092] When the aperture is 4.00000E+00, the sagitta is -3.74487E-01;

[0093] When the aperture is 6.00000E+00, the sagitta is -8.03945E-01;

[0094] When the aperture is 8.00000E+00, the sagitta is -1.30745E+00;

[0095] When the aperture is 1.00000E+01, the sagitta is -1.74318E+00;

[0096] When the aperture is 1.00000E+01, the sagitta is -1.82907E+00.

[0097] The image source surface of the second lens 2: This is the light-incident side surface, which bulges in the direction of incident light.

[0098] The radius of curvature R = 171.546 mm, and the conic coefficient K = -11827.5.

[0099] Even-order aspheric coefficients:

[0100] A2 = -2.69326E-02;

[0101] A4 = -5.08021E-05;

[0102] A6 = 1.96127E-06;

[0103] A8 = -3.13538E-08;

[0104] A10 = 3.68756E-10;

[0105] A12 = -2.73506E-12;

[0106] A14 = 1.14158E-14;

[0107] A16 = -1.97435E-17.

[0108] Sagittal values ​​corresponding to different aperture sizes:

[0109] When the aperture is 0.00000E+00, the sagitta is 0.00000E+00;

[0110] When the aperture is 2.00000E+00, the sagitta is -1.17343E-01;

[0111] When the aperture is 4.00000E+00, the sagitta is -4.62637E-01;

[0112] When the aperture is 6.00000E+00, the sagitta is -1.02193E+00;

[0113] When the aperture is 8.00000E+00, the sagitta is -1.75149E+00;

[0114] When the aperture is 1.00000E+01, the sagitta is -2.55733E+00;

[0115] When the aperture is 1.00000E+01, the sagitta is -3.20072E+00.

[0116] Projection effect example:

[0117] In one application scenario, the image emitted by an LCD screen 6 with a height of 55.12mm is first collimated by a Fresnel lens 7 with a focal length of F70. The distance between the Fresnel lens 7 and the image source side of the second lens 2 is 63.97mm, and the distance between the LCD screen 6 and the Fresnel lens is 6mm. After the light is modulated by this lens, a clear and bright large-size projected image with a height of 859.84mm can be presented on a screen 8 at a distance of 997.1mm from the imaging side of the first lens 1.

[0118] When the lens is adjusted towards the LCD screen 6, the farther the projection distance, the larger the projection size.

[0119] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A lens for a projector, comprising a lens body and a lens group disposed within the lens body, characterized in that: The lens group includes a first lens and a second lens. The first lens and the second lens are fixedly installed in the lens body from the imaging side to the image source side. Both the first lens and the second lens are meniscus lenses. The light-emitting side surfaces of the first lens and the second lens are concave towards the light-incident side, and the light-incident side surfaces of the first lens and the second lens are convex towards the incident light direction. Both the light-emitting side and the light-incident side surfaces of the first lens and the second lens are even-order aspherical surfaces.

2. The lens of a projector according to claim 1, characterized in that: The thickness of the middle part of the first lens and the second lens is greater than the thickness at the edge.

3. The lens of a projector according to claim 1, characterized in that: The refractive indices Nd1 and Nd2 of both the first and second lenses are in the range of 1.

45. <Nd<1.6。 4. The lens of a projector according to claim 3, characterized in that: The first and second lenses have the same refractive index.

5. A lens for a projector according to any one of claims 1-4, characterized in that: The Abbe numbers Vd1 and Vd2 of both the first and second lenses are in the range of 56.

5. <Vd<58.5。 6. The lens of a projector according to claim 5, characterized in that: The Abbe numbers of the first and second lenses are the same.

7. A lens for a projector according to any one of claims 1-4, characterized in that: The lens body includes a lens barrel and a front cover. The lens barrel has a hollow structure. A positioning step is provided on the image source side of the inner wall of the lens barrel. The lens group is paired and installed into the lens barrel from the imaging side. The image source side edge of the lens group contacts the positioning step. The front cover is closed to the imaging side of the lens barrel. The inner wall of the front cover presses against the imaging side edge of the lens group.

8. The lens of a projector according to claim 7, characterized in that: The outer wall of the lens barrel is provided with external threads and a lens mount, and the inner wall of the lens mount and the front cover are screwed to the lens barrel through internal threads.

9. A lens for a projector according to any one of claims 1-4, characterized in that: The first and second lenses are provided with retainers.

Images