Large-field-angle projection lens and imaging device
By designing a large field-of-view projection lens containing six aspherical lenses and optimizing lens parameters, the distortion problem of the projection lens under a large field of view was solved, enabling the projection of large images and miniaturization, and improving imaging quality and brightness.
Patent Information
- Application Number
- CN202511972344.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-03-03
AI Technical Summary
Existing projection lenses exhibit significant peripheral image distortion in areas with a large projection range, limiting their usability and making it difficult to meet the demands for a wide field of view.
Design a large field-of-view projection lens containing six aspherical lenses, satisfying conditions such as HFOV > 75° and 1mm < f < 2mm. By optimizing lens parameters such as Abbe number, refractive index, and total optical length, the number and volume of lenses are reduced, the optical path is optimized, and light dissipation and chromatic aberration are reduced.
It achieves a large field of view for the projection lens, making it easier to project larger images and increasing the range of applications. Furthermore, through miniaturization and improved imaging quality, it reduces distortion and enhances brightness and image quality.
Smart Images
Figure CN121596513A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optics, specifically to a large field-of-view projection lens and imaging device. Background Technology
[0002] A projection lens, also known as a projector lens, is the core optical component of a projector. Based on projection distance, they are categorized into short-throw, medium-throw, long-throw, and special types such as reflective and fisheye lenses. They are widely used in education, engineering, and home applications. The core parameter is the throw ratio, which is the ratio of projection distance to screen width. Short-throw lenses have a throw ratio of less than 1, while ultra-short-throw lenses can reach 0.25, enabling the projection of large images from short distances.
[0003] Currently, existing projection lenses are typically suitable for conference scenarios, but they usually have a low transmittance. For projects that need to be projected onto a large area, the distortion around the edges of the projected image is significant, limiting the applicability of these lenses. Summary of the Invention
[0004] This invention addresses the existing technical problems by providing a large field-of-view projection lens and imaging device.
[0005] The technical solution provided by this invention is as follows:
[0006] A large field-of-view projection lens, wherein the large field-of-view projection lens is composed of a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, an aperture, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens, in sequence from the object plane side to the image plane side.
[0007] The large field-of-view projection lens satisfies the following condition:
[0008] HFOV > 75°;
[0009] 1mm < f < 2mm;
[0010] Where f is the field of view of the large field of view projection lens, and HFOV is the half field of view of the large field of view projection lens.
[0011] In this technical solution, by setting the above parameters and structure, a large field of view of the projection lens is achieved, which makes it easier for the projection lens to project a larger image and increases the application range of the large field of view projection lens.
[0012] Preferably, the wide field-of-view projection lens comprises at least six aspherical lenses.
[0013] In this technical solution, the number of lenses used in a large field-of-view projection lens is reduced by using a large number of aspherical lenses, thereby reducing the size of the miniaturized projection lens and achieving miniaturization of the projection lens.
[0014] Preferably, the large field-of-view projection lens satisfies the following condition:
[0015] TTL < 15mm;
[0016] Wherein, TTL is the total optical length of the large field-of-view projection lens.
[0017] Preferably, the third lens satisfies the following condition:
[0018] Vd3 < 25;
[0019] Vd3 is the Abbe number of the third lens.
[0020] In this technical solution, by limiting the Abbe number of the third lens, the thickness of the third lens is reduced, while the optical path is optimized, the dissipation of light received by the aperture is reduced, and the brightness of the large field-of-view projection lens is increased.
[0021] Preferably, the fifth lens satisfies the following condition:
[0022] Vd5 < 25;
[0023] Vd5 is the Abbe number of the fifth lens.
[0024] In this technical solution, the optical path of the large field-of-view projection lens is optimized by limiting the Abbe number of the fifth lens, thereby increasing the imaging quality of the large field-of-view projection lens.
[0025] Preferably, the first lens satisfies the following condition:
[0026] Nd1 > 1.75;
[0027] Nd1 is the refractive index of the first lens.
[0028] In this technical solution, by limiting the refractive index of the first lens, the angle of light that the large field-of-view projection lens can receive is greatly increased, thus achieving the effect of a large aperture for the large field-of-view projection lens.
[0029] Preferably, the large field-of-view projection lens satisfies the following condition:
[0030] D47 / T47 < 0.15;
[0031] D47 is the sum of the gaps between the fourth and seventh lenses, and T47 is the total optical length of the fourth to seventh lenses.
[0032] In this technical solution, by limiting the above parameters, the gap between the fourth and seventh lenses is greatly reduced, realizing the miniaturization of the large field-of-view projection lens, reducing the light dissipation between the fourth and seventh lenses, and increasing the imaging quality of the large field-of-view projection lens.
[0033] Preferably, the large field-of-view projection lens satisfies the following condition:
[0034] Φ1 / TTL>0.8;
[0035] Wherein, Φ1 is the outer diameter of the first lens.
[0036] In this technical solution, by limiting the outer diameter of the first lens, the range of light that the first lens can receive is increased, further increasing the brightness of the image formed by the large field-of-view projection lens.
[0037] Preferably, the large field-of-view projection lens satisfies the following condition:
[0038] X3 / f > 1.5;
[0039] Wherein, X3 is the thickness of the third lens along the principal optical axis.
[0040] In this technical solution, by limiting the thickness of the third lens, the astigmatism and chromatic aberration of the large field-of-view projection lens are further reduced, thereby increasing the imaging quality of the large field-of-view projection lens.
[0041] One of the objectives of this invention is to provide an imaging device, comprising: a wide field-of-view projection lens; and an imaging element configured to receive an image formed by the wide field-of-view projection lens.
[0042] Compared with the prior art, the large field-of-view projection lens and imaging device provided by the present invention have the following beneficial effects:
[0043] 1. It achieves a large field of view for the projection lens, making it easier to project larger images and increasing the application range of the large field of view projection lens.
[0044] 2. The gap between the fourth and seventh lenses has been greatly reduced, enabling the miniaturization of the large field-of-view projection lens, reducing light dissipation between the fourth and seventh lenses, and increasing the imaging quality of the large field-of-view projection lens.
[0045] 3. By limiting the thickness of the third lens, astigmatism and chromatic aberration of the large field-of-view projection lens are further reduced, thereby increasing the imaging quality of the large field-of-view projection lens. Attached Figure Description
[0046] The preferred embodiments will now be described in a clear and easy-to-understand manner, with reference to the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of a large field-of-view projection lens and imaging device.
[0047] Figure 1 This is a schematic diagram of the structure of a large field-of-view projection lens according to the present invention;
[0048] Figure 2 This is an aberration diagram of a large field-of-view projection lens according to the present invention;
[0049] Figure 3 This is a coma diagram of a large field-of-view projection lens according to the present invention;
[0050] Figure 4 This is a schematic diagram of another large field-of-view projection lens of the present invention;
[0051] Figure 5 This is an aberration diagram of another large field-of-view projection lens of the present invention;
[0052] Figure 6 This is a first coma diagram of another large field-of-view projection lens of the present invention;
[0053] Figure 7 This is the second coma diagram of another large field-of-view projection lens of the present invention.
[0054] Explanation of the reference numerals: L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; STO, aperture stop; CG1, first protective glass; CG2, second protective glass. Detailed Implementation
[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0056] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."
[0057] Example 1
[0058] like Figure 1 and Figure 4 As shown, a large field-of-view projection lens is composed of, from the object plane side to the image plane side, a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, an aperture stop STO, a fourth lens L4 with positive optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, and a seventh lens L7 with positive optical power.
[0059] The large field-of-view projection lens satisfies the following condition:
[0060] HFOV > 75°;
[0061] 1mm < f < 2mm;
[0062] Where f is the field of view of the large field of view projection lens, and HFOV is the half field of view of the large field of view projection lens.
[0063] By setting the above parameters and structure, a large field of view of the projection lens is achieved, which makes it easier for the projection lens to project larger images and increases the application range of the large field of view projection lens.
[0064] The large field-of-view projection lens contains at least six aspherical lenses.
[0065] By using a large number of aspherical lenses, the number of lenses used in a large field-of-view projection lens is reduced, the size of the miniaturized projection lens is reduced, and miniaturization of the projection lens is achieved.
[0066] The large field-of-view projection lens satisfies the following condition:
[0067] TTL < 15mm;
[0068] Wherein, TTL is the total optical length of the large field-of-view projection lens.
[0069] The third lens L3 satisfies the following condition:
[0070] Vd3 < 25;
[0071] Vd3 is the Abbe number of the third lens L3.
[0072] By limiting the Abbe number of the third lens L3, the thickness of the third lens L3 was reduced, while the optical path was optimized, reducing the dissipation of light received by the aperture STO and increasing the brightness of the large field-of-view projection lens.
[0073] The fifth lens L5 satisfies the following condition:
[0074] Vd5 < 25;
[0075] Vd5 is the Abbe number of the fifth lens L5.
[0076] By limiting the Abbe number of the fifth lens L5, the optical path of the large field-of-view projection lens is optimized, thereby increasing the imaging quality of the large field-of-view projection lens.
[0077] The first lens L1 satisfies the following condition:
[0078] Nd1 > 1.75;
[0079] Nd1 is the refractive index of the first lens L1.
[0080] By limiting the refractive index of the first lens L1, the angle of light that the large field-of-view projection lens can receive is greatly increased, thus achieving the effect of a large aperture for the large field-of-view projection lens.
[0081] The large field-of-view projection lens satisfies the following condition:
[0082] D47 / T47 < 0.15;
[0083] D47 is the sum of the gaps between the fourth lens L4 and the seventh lens L7, and T47 is the total optical length of the fourth lens L4 to the seventh lens L7.
[0084] By limiting the parameters mentioned above, the gap between the fourth lens L4 and the seventh lens L7 is greatly reduced, realizing the miniaturization of the large field-of-view projection lens, reducing the light dissipation between the fourth lens L4 and the seventh lens L7, and increasing the imaging quality of the large field-of-view projection lens.
[0085] The large field-of-view projection lens satisfies the following condition:
[0086] Φ1 / TTL>0.8;
[0087] Wherein, Φ1 is the outer diameter of the first lens L1.
[0088] By limiting the outer diameter of the first lens L1, the range of light that the first lens L1 can receive is increased, further increasing the brightness of the image formed by the large field-of-view projection lens.
[0089] The large field-of-view projection lens satisfies the following condition:
[0090] X3 / f > 1.5;
[0091] Wherein, X3 is the thickness of the third lens L3 along the principal optical axis.
[0092] In this embodiment, by limiting the thickness of the third lens L3, the astigmatism and chromatic aberration of the large field-of-view projection lens are further reduced, thereby increasing the imaging quality of the large field-of-view projection lens.
[0093] Example 2
[0094] like Figures 1 to 3 As shown, a large field-of-view projection lens is composed of, from the object plane side to the image plane side, a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, an aperture stop STO, a fourth lens L4 with positive optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with positive optical power, a first protective glass CG1, and a second protective glass CG2.
[0095] The basic lens data of the large field-of-view projection lens in this embodiment are shown in Table 1, and the aspherical coefficients are shown in Table 2.
[0096] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.
[0097] In Table 2, K is the conic coefficient, and e is the scientific notation, for example, e-05 represents 10. -5 .
[0098] Table 1
[0099]
[0100]
[0101] Table 2
[0102]
[0103] In this embodiment, f = 1.23 mm, fno = 1.74, TTL = 13 mm, and HFOV = 85°;
[0104] Where f is the focal length of the miniaturized projection lens, fno is the aperture number of the miniaturized projection lens, HFOV is the half field of view of the miniaturized projection lens, and TTL is the total optical length of the miniaturized projection lens.
[0105] Vd3 = 21.54; Vd5 = 20.38;
[0106] Wherein, Vd3 is the Abbe number of the third lens L3, and Vd5 is the Abbe number of the fifth lens L5.
[0107] Nd1 = 1.8;
[0108] Wherein, Nd1 is the refractive index of the first lens L1.
[0109] Φ1=10.77mm, Φ1 / TTL=0.828;
[0110] Wherein, Φ1 is the outer diameter of the first lens L1.
[0111] X3 = 2mm, X3 / f = 1.63;
[0112] Wherein, X3 is the thickness of the third lens L3 along the principal optical axis.
[0113] D47=0.585mm, T47=4.212mm;
[0114] D47 / T47 = 0.139;
[0115] Wherein, D47 is the sum of the gaps between the fourth lens L4 and the seventh lens L7, and T47 is the total optical length of the fourth lens L4 to the seventh lens L7.
[0116] Example 3
[0117] like Figures 4 to 7 As shown, a large field-of-view projection lens is composed of, from the object plane side to the image plane side, a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, an aperture stop STO, a fourth lens L4 with positive optical power, a fifth lens L5 with negative optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with negative optical power, a first protective glass CG1, and a second protective glass CG2.
[0118] The basic lens data of the large field-of-view projection lens in this embodiment are shown in Table 3, and the aspherical coefficients are shown in Table 4.
[0119] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.
[0120] In Table 4, K is the conic coefficient, and e is the scientific notation, for example, e-05 represents 10. -5 .
[0121] Table 3
[0122] Face number Surface type radius of curvature / mm Center thickness / mm Refractive index Abbe number OBJ S1 spherical 8.553 1 1.80 46.57 S2 spherical 2.027 1.376 S3 aspherical -8.839 0.9 1.54 55.65 S4 aspherical 5.683 0.383 S5 aspherical 8.088 1.422 1.65 21.54 S6 aspherical -11.106 0.667 STO spherical INF -0.05 S8 aspherical 6.476 1.456 1.50 81.56 S9 aspherical -2.427 0.1 S10 aspherical 4.941 0.9 1.66 20.38 S11 aspherical 1.706 0.1 S12 aspherical 2.564 1.955 1.54 55.65 S13 aspherical -3.766 0.29 S14 aspherical 3.898 0.9 1.65 21.54 S15 aspherical 2.828 0.18 S16 spherical INF 0.21 1.52 64.14 S17 spherical INF 0.73 S18 spherical INF 0.21 1.52 64.2 S19 spherical INF 0.25 IMG
[0123] Table 4
[0124]
[0125]
[0126] In this embodiment, f = 1.72 mm, fno = 1.6, TTL = 12.979 mm, and HFOV = 85°;
[0127] Where f is the focal length of the miniaturized projection lens, fno is the aperture number of the miniaturized projection lens, HFOV is the half field of view of the miniaturized projection lens, and TTL is the total optical length of the miniaturized projection lens.
[0128] Vd3 = 21.54; Vd5 = 20.38;
[0129] Wherein, Vd3 is the Abbe number of the third lens L3, and Vd5 is the Abbe number of the fifth lens L5.
[0130] Nd1 = 1.8;
[0131] Wherein, Nd1 is the refractive index of the first lens L1.
[0132] Φ1=8.77mm, Φ1 / TTL=0.656;
[0133] Wherein, Φ1 is the outer diameter of the first lens L1.
[0134] X3=1.422mm, X3 / f=0.827;
[0135] Wherein, X3 is the thickness of the third lens L3 along the principal optical axis.
[0136] D47=0.49mm, T47=5.701mm;
[0137] D47 / T47 = 0.086;
[0138] Wherein, D47 is the sum of the gaps between the fourth lens L4 and the seventh lens L7, and T47 is the total optical length of the fourth lens L4 to the seventh lens L7.
[0139] Example 4
[0140] An imaging device, such as Figures 1 to 7 As shown, it includes: a large field-of-view projection lens as described in any of the above embodiments, and an imaging element configured to receive an image formed by the large field-of-view projection lens.
[0141] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A projection lens with a large field of view, characterized in that, The large field-of-view projection lens consists of a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, an aperture, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens, in sequence from the object plane side to the image plane side. The large field-of-view projection lens satisfies the following condition: HFOV > 75°; 1mm < f < 2mm; Where f is the field of view of the large field of view projection lens, and HFOV is the half field of view of the large field of view projection lens.
2. A large field-of-view projection lens according to claim 1, characterized in that: The large field-of-view projection lens contains at least six aspherical lenses.
3. A large field-of-view projection lens according to claim 1, characterized in that: The large field-of-view projection lens satisfies the following condition: TTL < 15mm; Wherein, TTL is the total optical length of the large field-of-view projection lens.
4. A large field-of-view projection lens according to claim 1, characterized in that: The third lens satisfies the following condition: Vd3 < 25; Vd3 is the Abbe number of the third lens.
5. A large field-of-view projection lens according to claim 1, characterized in that: The fifth lens satisfies the following condition: Vd5 < 25; Vd5 is the Abbe number of the fifth lens.
6. A large field-of-view projection lens according to claim 1, characterized in that: The first lens satisfies the following condition: Nd1 > 1.75; Nd1 is the refractive index of the first lens.
7. A large field-of-view projection lens according to claim 1, characterized in that: The large field-of-view projection lens satisfies the following condition: D47 / T47 < 0.15; D47 is the sum of the gaps between the fourth and seventh lenses, and T47 is the total optical length of the fourth to seventh lenses.
8. A large field-of-view projection lens according to claim 3, characterized in that: The large field-of-view projection lens satisfies the following condition: Φ1 / TTL>0.6; Wherein, Φ1 is the outer diameter of the first lens.
9. A large field-of-view projection lens according to claim 1, characterized in that: The large field-of-view projection lens satisfies the following condition: X3 / f > 0.8; Wherein, X3 is the thickness of the third lens along the principal optical axis.
10. An imaging device, characterized in that, include: A large field-of-view projection lens as described in any one of claims 1 to 9; An imaging element is configured to receive an image formed by the large field-of-view projection lens.