Full-spherical fisheye lens
By designing a specific lens combination and aperture structure, the global surface fisheye lens solves the problems of small field of view and unclear image quality of existing fisheye lenses, achieving a large field of view and high image quality, and is suitable for global surface projection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUZHOU SINOVA TECH
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-05
AI Technical Summary
Existing fisheye lenses have a maximum half field of view of less than 88° and project spherical images with unclear quality and complex optical structures.
Design a global fisheye lens, which includes a front lens group, a middle lens group and a rear lens group in sequence from the object side to the image side along the optical axis. The lens group is composed of glass spherical lenses of a specific type and arrangement, and an aperture is set to correct aberrations. Cemented lens groups and limiting structures are used between the lens groups to improve image quality.
It achieves a maximum half-field angle of 92°±0.5°, and the projected spherical image has clear picture quality. The optical structure is simple and suitable for mass production.
Smart Images
Figure CN224203504U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of fisheye lens technology, specifically to a global plane fisheye lens. Background Technology
[0002] Existing fisheye lenses typically consist of 5 to 6 spherical lenses of various shapes. While characterized by a simple optical structure, their maximum half-field of view (the maximum angle the lens can capture, i.e., the angle covered from the center point of the lens to the edge) cannot be large (usually less than 88°), and the projected spherical image quality is not very clear. With the continuous advancement of projection technology and the increasing demands on projection displays, there is a need to design a global fisheye lens with a large maximum half-field of view, high-resolution projected spherical images, and a relatively simple optical structure. Utility Model Content
[0003] This invention addresses the problems existing in the prior art by proposing a global surface fisheye lens that has a large maximum half-field of view, high image quality and clarity of the projected spherical image, and a relatively simple optical structure.
[0004] This utility model is achieved through the following technical solution:
[0005] A global fisheye lens, comprising a front lens group, an intermediate lens group, and a rear lens group in sequence along the optical axis from the object side to the image side;
[0006] The front lens group includes, in sequence along the optical axis from the object side to the image side, a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, and a fifth lens with negative optical power.
[0007] The intermediate lens group includes, in sequence along the optical axis from the object side to the image side, a sixth lens with negative optical power and a seventh lens with positive optical power;
[0008] The rear lens group includes, in sequence along the optical axis from the object side to the image side, an eighth lens with positive optical power, a ninth lens with negative optical power, a tenth lens with positive optical power, an eleventh lens with negative optical power, and a twelfth lens with positive optical power.
[0009] An aperture stop is provided between the seventh lens and the eighth lens.
[0010] Preferably, the first, second, and ninth lenses are concave-convex spherical lenses, the third and fifth lenses are biconcave spherical lenses, the sixth and eleventh lenses are plano-concave spherical lenses, and the fourth, seventh, eighth, tenth, and twelfth lenses are biconvex spherical lenses.
[0011] Preferably, the convex surface of the first lens faces the object side, the convex surface of the second lens faces the object side, the plane of the sixth lens faces the object side, the convex surface of the ninth lens faces the image side, and the plane of the eleventh lens faces the image side.
[0012] Preferably, there is a gap between any two adjacent lenses in the first, second, third, and fourth lenses; a gap between the fifth and sixth lenses; a gap between the seventh lens and the aperture stop; a gap between the aperture stop and the eighth lens; a gap between the ninth and tenth lenses; a gap between the eleventh and twelfth lenses; the fourth and fifth lenses are arranged close together; the sixth and seventh lenses are arranged close together; the eighth and ninth lenses are arranged close together; and the tenth and eleventh lenses are arranged close together.
[0013] Preferably, the center distance between the seventh lens and the aperture stop is greater than the center distance between the aperture stop and the eighth lens.
[0014] Preferably, the fourth and fifth lenses are two cemented lens groups; the sixth and seventh lenses are two cemented lens groups; the eighth and ninth lenses are two cemented lens groups; and the tenth and eleventh lenses are two cemented lens groups.
[0015] Preferably, the global-angle fisheye lens also includes a first lens barrel and a second lens barrel, with a front lens group disposed at the end of the first lens barrel near the object side, a middle lens group disposed at the end of the second lens barrel near the object side, and a rear lens group disposed at the end of the second lens barrel near the image side. The end of the first lens barrel near the image side and the end of the second lens barrel near the object side are detachably connected by a connector.
[0016] In summary, this utility model has the following beneficial effects:
[0017] This utility model discloses a global fisheye lens, which, along the optical axis from the object side to the image side, sequentially includes a front lens group, a middle lens group, and a rear lens group. The front lens group, along the optical axis from the object side to the image side, sequentially includes a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, and a fifth lens with negative optical power. The middle lens group, along the optical axis from the object side to the image side, sequentially includes a sixth lens with negative optical power and a seventh lens with positive optical power. The rear lens group, along the optical axis from the object side to the image side, includes, in sequence, an eighth lens with positive optical power, a ninth lens with negative optical power, a tenth lens with positive optical power, an eleventh lens with negative optical power, and a twelfth lens with positive optical power. An aperture stop is provided between the seventh and eighth lenses. This fisheye lens structure can not only achieve a large maximum half field of view (92°±0.5°), but also project a spherical image with high clarity, and its optical structure is relatively simple.
[0018] Further or more detailed beneficial effects will be described in conjunction with specific embodiments in the detailed implementation. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of a global fisheye lens according to this utility model;
[0020] Figure 2 This is a light path diagram of a global fisheye lens according to this utility model;
[0021] Figure 3 These are real-world images captured using an existing fisheye lens.
[0022] Figure 4 This is a real-life image of a global fisheye lens according to this utility model. Detailed Implementation
[0023] The present invention will be further described in detail below with reference to the accompanying drawings.
[0024] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.
[0025] like Figure 1 As shown, this embodiment discloses a global surface fisheye lens, which includes a front lens group, an intermediate lens group and a rear lens group in sequence from the object side to the image side along the optical axis.
[0026] The front lens group, arranged sequentially along the optical axis from the object side to the image side, includes a first lens 1 with negative optical power, a second lens 2 with negative optical power, a third lens 3 with negative optical power, a fourth lens 4 with positive optical power, and a fifth lens 5 with negative optical power. The front lens group is the part of the lens closest to the subject being photographed, and its main task is to collect as much light as possible from different angles.
[0027] The intermediate lens group, arranged sequentially along the optical axis from the object side to the image side, includes a sixth lens 6 with negative optical power and a seventh lens 7 with positive optical power. The main function of the intermediate lens group is to further process the light rays transmitted from the front lens group.
[0028] The rear lens group, arranged sequentially along the optical axis from the object side to the image side, includes an eighth lens 8 with positive optical power, a ninth lens 9 with negative optical power, a tenth lens 10 with positive optical power, an eleventh lens 11 with negative optical power, and a twelfth lens 12 with positive optical power. Although most aberrations have been addressed in the front and intermediate lens groups during correction, the rear lens group can still further correct residual aberrations, such as chromatic aberration and spherical aberration. Through proper design, the rear lens group can perform final fine-tuning of these aberrations to achieve optimal imaging results.
[0029] An aperture stop 23 is provided between the seventh lens 7 and the eighth lens 8.
[0030] The total length of the fisheye lens in this embodiment (i.e., the length from the vertex of the outer surface of the first lens 1 to the vertex of the outer surface of the twelfth lens 12) can be 250mm; the object plane distance of the fisheye lens in this embodiment (i.e., the distance from the vertex of the outer surface of the first lens 1 to the object plane) can be 300mm.
[0031] Specifically, such as Figure 1 As shown, lens 1, lens 2, and lens 9 are concave-convex spherical lenses; lens 3 and lens 5 are biconcave spherical lenses; lens 6 and lens 11 are plano-concave spherical lenses; and lens 4, lens 7, lens 8, lens 10, and lens 12 are biconvex spherical lenses. All of these lenses—concave-convex, biconcave, plano-concave, and biconvex—are made of glass spherical lenses. Glass is easy to grind and has low processing costs, making it suitable for mass production.
[0032] The convex surface of the first lens 1 faces the object side, the convex surface of the second lens 2 faces the object side, the plane of the sixth lens 6 faces the object side, the convex surface of the ninth lens 9 faces the image side, and the plane of the eleventh lens 11 faces the image side.
[0033] Among them, the absolute value of the object-side convex surface curvature radius of the first lens 1 is greater than the absolute value of the image-side concave surface curvature radius of the first lens 1; the absolute value of the object-side convex surface curvature radius of the second lens 2 is greater than the absolute value of the image-side concave surface curvature radius of the second lens 2; the absolute value of the object-side concave surface curvature radius of the third lens 3 is greater than the absolute value of the image-side concave surface curvature radius of the third lens 3; the absolute value of the object-side convex surface curvature radius of the fourth lens 4 is greater than the absolute value of the image-side convex surface curvature radius of the fourth lens 4; and the absolute value of the object-side concave surface curvature radius of the fifth lens 5 is less than the absolute value of the image-side concave surface curvature radius of the fifth lens 5. The absolute value of the object-side convex surface curvature radius of the second lens 2 is greater than the absolute value of the image-side concave surface curvature radius of the first lens 1; the absolute value of the object-side concave surface curvature radius of the third lens 3 is greater than the absolute value of the image-side concave surface curvature radius of the second lens 2; the absolute value of the object-side convex surface curvature radius of the fourth lens 4 is greater than the absolute value of the image-side concave surface curvature radius of the third lens 3; and the absolute value of the object-side concave surface curvature radius of the fifth lens 5 is equal to the absolute value of the image-side convex surface curvature radius of the fourth lens 4.
[0034] The absolute value of the object-side convex surface radius of curvature of the seventh lens 7 is less than the absolute value of the image-side convex surface radius of curvature of the seventh lens 7; the absolute value of the image-side concave surface radius of curvature of the sixth lens 6 is equal to the absolute value of the object-side convex surface radius of curvature of the seventh lens 7.
[0035] The absolute value of the object-side convex surface radius of curvature of the eighth lens 8 is greater than the absolute value of the image-side convex surface radius of curvature of the eighth lens 8; the absolute value of the object-side concave surface radius of curvature of the ninth lens 9 is less than the absolute value of the image-side convex surface radius of curvature of the ninth lens 9; the absolute value of the object-side convex surface radius of curvature of the tenth lens 10 is greater than the absolute value of the image-side convex surface radius of curvature of the tenth lens 10; the absolute value of the object-side convex surface radius of curvature of the twelfth lens 12 is greater than the absolute value of the image-side convex surface radius of curvature of the twelfth lens 12. The absolute value of the object-side concave surface radius of curvature of the ninth lens 9 is equal to the absolute value of the image-side convex surface radius of curvature of the eighth lens 8; the absolute value of the object-side convex surface radius of curvature of the tenth lens 10 is greater than the absolute value of the image-side convex surface radius of curvature of the ninth lens 9; the absolute value of the object-side concave surface radius of curvature of the eleventh lens 11 is equal to the absolute value of the image-side convex surface radius of curvature of the tenth lens 10.
[0036] Furthermore, there is a gap between any two adjacent lenses in the first lens 1, second lens 2, third lens 3, and fourth lens 4; there is a gap between the fifth lens 5 and the sixth lens 6; there is a gap between the seventh lens 7 and the aperture stop 23; there is a gap between the aperture stop 23 and the eighth lens 8; there is a gap between the ninth lens 9 and the tenth lens 10; there is a gap between the eleventh lens 11 and the twelfth lens 12; the fourth lens 4 and the fifth lens 5 are placed close together; the sixth lens 6 and the seventh lens 7 are placed close together; the eighth lens 8 and the ninth lens 9 are placed close together; and the tenth lens 10 and the eleventh lens 11 are placed close together.
[0037] The center distance between the seventh lens 7 and the aperture 23 is greater than the center distance between the aperture 23 and the eighth lens 8. By appropriately selecting the position of the aperture 23, aberrations related to the aperture 23 (such as coma, astigmatism, distortion, and axial chromatic aberration) can be corrected to improve the image quality of the lens.
[0038] Furthermore, the fourth lens 4 and the fifth lens 5 are two cemented lens groups; the sixth lens 6 and the seventh lens 7 are two cemented lens groups; the eighth lens 8 and the ninth lens 9 are two cemented lens groups; and the tenth lens 10 and the eleventh lens 11 are two cemented lens groups. Cemented lens groups, also known as achromatic or distortion-correcting lens groups, are formed by cementing two single lenses together. Their performance in polychromatic (white light) imaging is significantly improved compared to single-lens systems. Achromatic lens groups, composed of two lenses made of different materials cemented together, correct the dispersion of the glass. Distortion-correcting lens groups, through a combination of materials and curvature, correct the optical distortion of projected light.
[0039] like Figure 2 As shown, light enters through the object-side convex surface of the first lens 1 and then exits through the image-side concave surface of the first lens 1. The opposing surfaces of the first lens 1 and the second lens 2 are in contact at their periphery. Light rays exiting from the first lens 1 enter through the object-side convex surface of the second lens 2 and then exit through the image-side concave surface of the second lens 2. The opposing surfaces of the second lens 2 and the third lens 3 are in contact at their periphery. Light rays exiting from the second lens 2 enter through the object-side concave surface of the third lens 3 and then exit through the image-side concave surface of the third lens 3. The opposing surfaces of the third lens 3 and the fourth lens 4 are in contact at their periphery. Light rays exiting from the third lens 3 enter through the object-side convex surface of the fourth lens 4 and then exit through the image-side convex surface of the fourth lens 4. The opposing surfaces of the fourth lens 4 and the fifth lens 5 are in close contact. Light rays exiting from the fourth lens 4 directly enter through the object-side concave surface of the fifth lens 5 and then exit through the image-side concave surface of the fifth lens 5. The front lens group is mainly used to collect as much light as possible from different angles and to make the light tend to converge toward the central optical axis.
[0040] Light rays emitted from the fifth lens 5 enter through the object-side plane of the sixth lens 6 and exit through the image-side concave surface of the sixth lens 6. The opposing surfaces of the fifth lens 5 and the seventh lens 7 are set in close contact, and light rays emitted from the fifth lens 5 directly enter through the object-side convex surface of the seventh lens 7 and exit through the image-side convex surface of the seventh lens 7. The intermediate lens group is mainly used to receive all the light rays emitted from the front lens group and converge the light rays.
[0041] Light rays emitted from the seventh lens 7 enter from the object side of the aperture 23 and exit from the image side of the aperture 23. The aperture 23 is primarily used to adjust the amount of light passing through. Furthermore, the aperture 23 can correct aberrations associated with it (e.g., coma, astigmatism, distortion, and axial chromatic aberration) to improve the image quality of the lens.
[0042] Light rays emitted from aperture 23 enter through the object-side convex surface of the eighth lens 8 and exit through the image-side convex surface of the eighth lens 8. The opposing surfaces of the eighth lens 8 and the ninth lens 9 are in close contact; light rays emitted from the eighth lens 8 enter directly through the object-side concave surface of the ninth lens 9 and exit through the image-side convex surface of the ninth lens 9. The opposing surfaces of the ninth lens 9 and the tenth lens 10 are in contact at the center position; light rays emitted from the ninth lens 9 enter through the object-side convex surface of the tenth lens 10 and exit through the image-side convex surface of the tenth lens 10. The opposing surfaces of the tenth lens 10 and the eleventh lens 11 are in close contact; light rays emitted from the tenth lens 10 enter directly through the object-side concave surface of the eleventh lens 11 and exit through the image-side plane of the eleventh lens 11. The eleventh lens 11 and the twelfth lens 12 are not in contact; light rays emitted from the eleventh lens 11 enter through the object-side convex surface of the twelfth lens 12 and exit through the image-side convex surface of the twelfth lens 12. The rear lens group is mainly used to receive the light emitted by the aperture 23 and to make these light rays tend to converge toward the central optical axis, so that all the light rays can be projected onto the imaging surface of the required range.
[0043] The fisheye lens of this embodiment has a large maximum half field of view (up to 92°±0.5°) for emitted light, and the image quality of the spherical image it projects is high. Figure 3 These are real-world images captured by an existing fisheye lens. Figure 4 These are actual images captured by the fisheye lens in this embodiment. A comparison shows that the spherical image projected by the fisheye lens in this embodiment has higher image quality and clarity, and its optical structure is relatively simple. The maximum half-field of view is half the maximum angle the lens can capture, that is, the angle covered from the center point of the lens to the edge. Since the maximum half-field of view of the fisheye lens in this embodiment can reach 92 degrees, a single fisheye lens can achieve hemispherical projection. Therefore, by setting two fisheye lenses back-to-back, the images of the front and rear hemispheres can be captured separately. Then, by stitching the images of the two hemispheres together using existing software algorithms, a global projection can be achieved.
[0044] In addition, such as Figure 1As shown, the global fisheye lens of this embodiment also includes a first lens barrel 13 and a second lens barrel 14. A front lens group is disposed at the object-side end of the first lens barrel 13, an intermediate lens group is disposed at the object-side end of the second lens barrel 14, and a rear lens group is disposed at the image-side end of the second lens barrel 14. The image-side end of the first lens barrel 13 and the object-side end of the second lens barrel 14 are detachably connected via a connector 24. Specifically, the first lens 1, second lens 2, third lens 3, fourth lens 4, and fifth lens 5 are disposed at the object-side end of the first lens barrel 13; the sixth lens 6 and seventh lens 7 are disposed at the object-side end of the second lens barrel 14; and the eighth lens 8, ninth lens 9, tenth lens 10, eleventh lens 11, and twelfth lens 12 are disposed at the image-side end of the second lens barrel 14. The connector 24 can be a screw. The arrangement of the first lens barrel 13 and the second lens barrel 14 facilitates the installation of the intermediate lens group, thereby facilitating the assembly of the entire intermediate lens group.
[0045] The global fisheye lens of this embodiment also includes a first limiting member 15 connected to the first lens barrel 13 and used to limit the first lens 1 in the length direction of the first lens barrel 13; a second limiting member 16 connected to the first lens barrel 13 and used to limit the second lens 2 in the length direction of the first lens barrel 13; a third limiting member 17 connected to the first lens barrel 13 and used to limit the fourth lens 4 in the length direction of the first lens barrel 13; a fourth limiting member 18 connected to the second lens barrel 14 and used to limit the sixth lens 6 in the length direction of the second lens barrel 14; a fifth limiting member 19 connected to the second lens barrel 14 and used to limit the aperture stop 23; a sixth limiting member 20 connected to the second lens barrel 14 and used to limit the ninth lens 9 in the length direction of the second lens barrel 14; a seventh limiting member 21 connected to the second lens barrel 14 and used to limit the eleventh lens 11 in the length direction of the second lens barrel 14; and an eighth limiting member 22 connected to the second lens barrel 14 and used to limit the twelfth lens 12 in the length direction of the second lens barrel 14.
[0046] The first limiting component 15, the second limiting component 16, the third limiting component 17, the fourth limiting component 18, the fifth limiting component 19, the sixth limiting component 20, the seventh limiting component 21, and the eighth limiting component 22 are used to securely assemble the lens. Common structural components, such as retaining rings, can be used to fix the lens inside the lens barrel; other structural forms are not limited. The aforementioned structural components can be made of aluminum. The focusing method uses a whole-group adjustment, thus avoiding the problems of complex lens structure and difficult focusing caused by partial focusing.
[0047] The global fisheye lens in this embodiment also includes a lens connector 25 connected to the outer peripheral wall of the second lens barrel 14. The lens connector 25 is used to connect and fix the global fisheye lens to the external mounting bracket to prevent the connection from becoming loose during use.
Claims
1. A global fisheye lens, characterized in that, Along the optical axis, from the object side to the image side, the lenses consist of a front lens group, an intermediate lens group, and a rear lens group in sequence. The front lens group includes, in sequence along the optical axis from the object side to the image side, a first lens (1) with negative optical power, a second lens (2) with negative optical power, a third lens (3) with negative optical power, a fourth lens (4) with positive optical power, and a fifth lens (5) with negative optical power. The intermediate lens group includes, along the optical axis from the object side to the image side, a sixth lens (6) with negative optical power and a seventh lens (7) with positive optical power. The rear lens group includes, in sequence along the optical axis from the object side to the image side, an eighth lens (8) with positive optical power, a ninth lens (9) with negative optical power, a tenth lens (10) with positive optical power, an eleventh lens (11) with negative optical power, and a twelfth lens (12) with positive optical power. An aperture stop (23) is provided between the seventh lens (7) and the eighth lens (8).
2. The global-angle fisheye lens according to claim 1, characterized in that, The first lens (1), the second lens (2), and the ninth lens (9) are concave-convex spherical lenses, the third lens (3) and the fifth lens (5) are biconcave spherical lenses, the sixth lens (6) and the eleventh lens (11) are plano-concave spherical lenses, and the fourth lens (4), the seventh lens (7), the eighth lens (8), the tenth lens (10), and the twelfth lens (12) are biconvex spherical lenses.
3. The global-angle fisheye lens according to claim 2, characterized in that, The convex surface of the first lens (1) faces the object side, the convex surface of the second lens (2) faces the object side, the plane of the sixth lens (6) faces the object side, the convex surface of the ninth lens (9) faces the image side, and the plane of the eleventh lens (11) faces the image side.
4. The global-angle fisheye lens according to claim 3, characterized in that, There is a gap between any two adjacent lenses in the first lens (1), second lens (2), third lens (3), and fourth lens (4); there is a gap between the fifth lens (5) and the sixth lens (6); there is a gap between the seventh lens (7) and the aperture stop (23); there is a gap between the aperture stop (23) and the eighth lens (8); there is a gap between the ninth lens (9) and the tenth lens (10); there is a gap between the eleventh lens (11) and the twelfth lens (12); the fourth lens (4) and the fifth lens (5) are closely attached; the sixth lens (6) and the seventh lens (7) are closely attached; the eighth lens (8) and the ninth lens (9) are closely attached; the tenth lens (10) and the eleventh lens (11) are closely attached.
5. The global-angle fisheye lens according to claim 4, characterized in that, The center distance between the seventh lens (7) and the aperture stop (23) is greater than the center distance between the aperture stop (23) and the eighth lens (8).
6. The global fisheye lens according to claim 4, characterized in that, The fourth lens (4) and the fifth lens (5) are two cemented lens groups; the sixth lens (6) and the seventh lens (7) are two cemented lens groups; the eighth lens (8) and the ninth lens (9) are two cemented lens groups; the tenth lens (10) and the eleventh lens (11) are two cemented lens groups.
7. The global fisheye lens according to claim 1, characterized in that, The global fisheye lens also includes a first lens barrel (13) and a second lens barrel (14). The front lens group is disposed at the object-side end of the first lens barrel (13), the middle lens group is disposed at the object-side end of the second lens barrel (14), and the rear lens group is disposed at the image-side end of the second lens barrel (14). The image-side end of the first lens barrel (13) and the object-side end of the second lens barrel (14) are detachably connected by a connector (24).