Variable focal length pinhole lens optical system and imaging method thereof
By designing the four -sets zoom transmitted photocarians, the continuous zoom of 4 to 16mm is achieved using the movement of the change group and the compensation group to solve the problem that the existing fixed focal length pinhole lens cannot be transformed. Effect.
Patent Information
- Application Number
- CN202110705553.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-06-24
- Publication Date
- 2025-01-28
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing fixed focal length pinhole lenses cannot achieve focal length change, resulting in fixed monitoring screen size and field of view angle, and it is impossible to amplify and analyze valuable information in real time.
Design a four -set zoom transmitted optical system. The continuous zoom of 4 to 16mm is achieved by the movement of the variable group and the compensation group, and a standard spherical lens is used to ensure imaging quality.
With the case without increasing the number of lenses, a 4x continuous zoom is achieved through a lens. The imaging quality is excellent, and it matches one -third of the CCD.
Smart Images
Figure CN113325559B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a variable focal length pinhole lens optical system and an imaging method thereof, belonging to the technical field of optics. Background Art
[0002] Currently, fixed focal length pinhole lenses are basically used in the market. However, due to the fixed focal length, the size of the monitored screen and the field of view are fixed, and it is impossible to magnify and analyze the captured valuable information in real time. The present invention is a variable focal length pinhole lens, which can achieve 4 times continuous zoom with one lens without increasing the number of lenses, and has excellent imaging quality. Summary of the invention
[0003] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a zoom pinhole lens optical system and an imaging method thereof, which can achieve 4-16mm continuous zooming through the movement of a zoom group and two compensation groups.
[0004] In order to solve the above technical problems, the technical solution of the present invention is: a zoom pinhole lens optical system, the optical system is a four-component zoom transmission structure, working in the visible light band, from the object side to the image side along the axial light incident from left to right coaxially arranged aperture, front fixed group A, variable power group B, compensation group C, compensation group D; the front fixed group A is provided with a positive focal length crescent lens A1, a positive focal length crescent lens A2 and a negative focal length crescent lens A3 composed of a double cemented positive lens group; the variable power group B is provided with a positive focal length biconvex lens B1 and a positive focal length double convex lens B2; the positive focal length double convex lens B3 is provided with a positive focal length double convex lens B4 and a positive focal length double convex lens B5; the positive focal length double convex lens B6 is provided with a positive focal length double convex lens B7; the positive focal length double convex lens B8 is provided with a positive focal length double convex lens B9; the positive focal length double convex lens B10 is provided with a positive focal length double convex lens B111; the positive focal length double convex lens B20 is provided with a positive focal length double convex lens B120 is provided with a positive focal length double convex lens B20 is provided with a positive focal length double convex lens B30 is provided with a positive focal length double convex lens B10 is provided with a positive focal length double convex lens B10 is provided with a positive focal length double convex lens B20 is provided with a positive focal length double convex lens B3 ... The compensation group C is sequentially provided with a biconcave lens C1 with negative power, a crescent lens C2 with positive power, a crescent lens C3 with positive power, a crescent lens C4 with negative power, a crescent lens C5 with negative power, and a crescent lens C6 with positive power; the compensation group D is sequentially provided with a double cemented positive lens group consisting of a biconvex lens D1 with positive power, a crescent lens D2 with negative power, and a crescent lens D3 with positive power.
[0005] Preferably, the focal length of the optical system is continuously variable from 4 to 16 mm.
[0006] Preferably, the focal length of the front fixed group A is f A '=35~37mm, the focal length of the zoom group B is f B '=20~21mm, the focal length of the compensation group C is f C ' = -121.5 ~ -124mm, the focal length of the compensation group D is f D ′=17~18mm.
[0007] Preferably, the distance between the aperture and the CCD image plane is fixed; the air gap between the aperture and the front fixed group A is fixed; the air gap between the front fixed group A and the zoom group B is variable from 0.3 to 18.9 mm; the air gap between the zoom group B and the compensation group C is variable from 4.05 to 28.96 mm, the air gap between the compensation group C and the compensation group D is variable from 0.3 to 2 mm, and the air gap between the compensation group D and the CCD image plane is variable from 17.19 to 21.82 mm; a continuously variable focal length of 4 to 16 mm can be obtained by changing the above-mentioned gaps.
[0008] Preferably, the light beam is imaged for the first time after passing through the aperture, the front fixed group A, and the zoom group B, and the primary image plane is located between the zoom group B and the compensation group C. The primary image plane is imaged for the second time after passing through the compensation group C and the compensation group D, and the secondary image plane is located on the CCD.
[0009] Preferably, the diaphragm is arranged at the front end of the lens, and the size of the diaphragm hole remains unchanged during the zooming process.
[0010] Preferably, the distance between the aperture and the CCD image plane remains unchanged during the zooming process.
[0011] Preferably, all lenses adopt standard spherical surfaces.
[0012] An imaging method for a zoom pinhole lens optical system is performed according to the following steps: light rays pass through an aperture, a crescent lens A1, a crescent lens A2, a crescent lens A3, a biconvex lens B1, a crescent lens B2, a biconvex lens B3, a crescent lens B4, a biconcave lens C1, a crescent lens C2, a crescent lens C3, a crescent lens C4, a crescent lens C5, a crescent lens C6, a biconvex lens D1, a crescent lens D2, and a crescent lens D3 from left to right in sequence, and then an image is formed on a CCD.
[0013] Compared with the prior art, the present invention has the following beneficial effects: all lenses of the present invention adopt standard spherical surfaces, and under the condition of ensuring excellent imaging quality, the focal length can be continuously changed from 4mm to 16mm by changing the air interval between the front fixed group A and the zoom group B, the air interval between the zoom group B and the compensation group C, the air interval between the compensation group C and the compensation group D, and the air interval between the compensation group D and the CCD image plane. It matches with a one-third inch CCD. The imaging quality is excellent.
[0014] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is an optical system diagram of the present invention with a focal length of 4 mm.
[0016] Figure 2This is an optical system diagram of the present invention with a focal length of 10 mm.
[0017] Figure 3 This is an optical system diagram of the present invention with a focal length of 16 mm.
[0018] Figure 4 This is a transfer function evaluation diagram of the CCD image plane position with a focal length of 4 mm in the implementation of the present invention.
[0019] Figure 5 This is a transfer function evaluation diagram of the CCD image plane position with a focal length of 10 mm in the implementation of the present invention.
[0020] Figure 6 This is a transfer function evaluation diagram of the CCD image plane position with a focal length of 16 mm in the implementation of the present invention.
[0021] In the figure: A1 crescent lens A1, A2 crescent lens A2, A3 crescent lens A3, B1 biconvex lens B1, B2 crescent lens B2, B3 biconvex lens B3, B4 crescent lens B4, C1 biconcave lens C1, C2 crescent lens C2, C3 crescent lens C3, C4 crescent lens C4, C5 crescent lens C5, C6 crescent lens C6, D1 biconvex lens D1, D2 crescent lens D2, D3 crescent lens D3, A front fixed group A, B zoom group B, C compensation group C, D compensation group D. DETAILED DESCRIPTION
[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0023] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.
[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0025] like Figures 1 to 6As shown, this embodiment provides a zoom pinhole lens optical system, which is a four-component zoom transmission structure, working in the visible light band, and the diaphragm, front fixed group A, variable power group B, compensation group C, and compensation group D are coaxially arranged in sequence along the axial light incident from left to right from the object side to the image side; the front fixed group A is sequentially provided with a double cemented positive lens group consisting of a positive focal power crescent lens A1, a positive focal power crescent lens A2, and a negative focal power crescent lens A3; the variable power group B is sequentially provided with a positive focal power biconvex lens B1 and a positive focal power crescent lens B2; The compensation group C is sequentially provided with a biconcave lens C1 with negative power, a crescent lens C2 with positive power, a crescent lens C3 with positive power, a crescent lens C4 with negative power, a crescent lens C5 with negative power, and a crescent lens C6 with positive power; the compensation group D is sequentially provided with a double cemented positive lens group consisting of a biconvex lens D1 with positive power, a crescent lens D2 with negative power, and a crescent lens D3 with positive power.
[0026] In the embodiment of the present invention, the focal length of the optical system is continuously variable from 4 to 16 mm.
[0027] In the embodiment of the present invention, the focal length of the front fixed group A is f A '=36.06mm, the focal length of the zoom group B is f B '=20.72mm, the focal length of the compensation group C is f C ' = -122.53mm, the focal length of the compensation group D is f D ′=17.17mm.
[0028] In the embodiment of the present invention, the distance between the aperture and the CCD image plane is fixed; the air interval between the aperture and the front fixed group A is fixed and is 5.74 mm; the air interval between the front fixed group A and the zoom group B is variable from 0.3 to 18.9 mm; the air interval between the zoom group B and the compensation group C is variable from 4.05 to 28.96 mm, the air interval between the compensation group C and the compensation group D is variable from 0.3 to 2 mm, and the air interval between the compensation group D and the CCD image plane is variable from 17.19 to 21.82 mm; a continuously variable focal length of 4 to 16 mm can be obtained by changing the above intervals.
[0029] In an embodiment of the present invention, the light beam is imaged for the first time after passing through the aperture, the front fixed group A, and the zoom group B, and the primary image plane is located between the zoom group B and the compensation group C. The primary image plane is imaged for the second time after passing through the compensation group C and the compensation group D, and the secondary image plane is located on the CCD.
[0030] In the embodiment of the present invention, the diaphragm is arranged at the front end of the lens to facilitate concealed shooting. The size of the diaphragm hole remains unchanged during the zooming process and is a pinhole with a diameter of 2 mm.
[0031] In the embodiment of the present invention, the distance between the aperture and the CCD image plane remains unchanged during the zooming process, and continuous optical zooming is achieved by moving the zoom group B, the compensation group C, and the compensation group D.
[0032] In the embodiment of the present invention, all lenses adopt standard spherical surfaces.
[0033] In the embodiment of the present invention, the technical indicators of the zoom pinhole lens optical system are as follows:
[0034] Spectral range: 400nm~700nm;
[0035] Effective relative aperture: 1:2~1:8;
[0036] Focal length: 4-16mm;
[0037] Field of view: 21.2°~73.7°;
[0038] Total optical length: 131.5mm.
[0039] In the embodiment of the present invention, the optical system parameters of the zoom pinhole lens are as follows:
[0040]
[0041]
[0042]
[0043] In an embodiment of the present invention, Figure 4 When the focal length of the present invention is 4 mm, at 100 lp / mm (line pairs / millimeter), the full field MTF (modulation transfer function) is greater than 0.4; Figure 5 When the focal length of the present invention is 10mm, at 100lp / mm (line pairs / mm), the full field MTF (modulation transfer function) is greater than 0.4. Figure 6 When the focal length of the present invention is 16 mm, at 100 lp / mm (line pairs / millimeter), the full-field MTF (modulation transfer function) is greater than 0.3, matching a CCD with a pixel size of 5×5 microns and one-third of an inch.
[0044] An imaging method for a zoom pinhole lens optical system is performed according to the following steps: light rays pass through an aperture, a crescent lens A1, a crescent lens A2, a crescent lens A3, a biconvex lens B1, a crescent lens B2, a biconvex lens B3, a crescent lens B4, a biconcave lens C1, a crescent lens C2, a crescent lens C3, a crescent lens C4, a crescent lens C5, a crescent lens C6, a biconvex lens D1, a crescent lens D2, and a crescent lens D3 from left to right in sequence, and then an image is formed on a CCD.
[0045] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.
Claims
1. A variable focal length pinhole lens optical system, characterized in that: The optical system is a four-component zoom transmission structure, working in the visible light band, and is composed of an aperture, a front fixed group A, a zoom group B, a compensation group C and a compensation group D which are coaxially arranged from the object side to the image side; the front fixed group A is composed of a double-cemented positive lens group consisting of a positive focal length crescent lens A1, a positive focal length crescent lens A2 and a negative focal length crescent lens A3 which are arranged in sequence; the zoom group B is composed of a double-cemented positive lens group consisting of a positive focal length biconvex lens B1 and a positive focal length crescent lens B2 which are arranged in sequence, a positive focal length biconvex lens B3 and a negative focal length The compensation group C is composed of a double-cemented positive lens group composed of a crescent lens B4 with a negative focal power; the compensation group C is composed of a negative focal power biconcave lens C1, a positive focal power crescent lens C2, a positive focal power crescent lens C3, a negative focal power crescent lens C4, a negative focal power crescent lens C5, and a positive focal power crescent lens C6 arranged in sequence; the compensation group D is composed of a double-cemented positive lens group composed of a positive focal power biconvex lens D1, a negative focal power crescent lens D2, and a positive focal power crescent lens D3 arranged in sequence; the focal length of the optical system is continuously variable from 4 to 16 mm; the focal length of the front fixed group A is f A ′=35~37mm, the focal length of the zoom group B f B ′=20~21mm, the focal length of the compensation group C f C ′=-121.5~-124mm, the focal length of the compensation group D f D ′=17~18mm; the distance between the aperture and the CCD image plane is fixed; the air interval between the aperture and the front fixed group A is fixed; the air interval between the front fixed group A and the zoom group B is variable at 0.3~18.9mm; the air interval between the zoom group B and the compensation group C is variable at 4.05~28.96mm, the air interval between the compensation group C and the compensation group D is variable at 0.3~2mm, and the air interval between the compensation group D and the CCD image plane is variable at 17.19~21.82mm; a continuously variable focal length of 4~16mm can be obtained by changing the above intervals.
2. The zoom pinhole lens optical system according to claim 1, characterized in that: The light beam is imaged for the first time after passing through the aperture, the front fixed group A, and the zoom group B. The primary image plane is located between the zoom group B and the compensation group C. The primary image plane is imaged for the second time after passing through the compensation group C and the compensation group D. The secondary image plane is located on the CCD.
3. The zoom pinhole lens optical system according to claim 1, characterized in that: The aperture is set at the front end of the lens, and the size of the aperture hole remains unchanged during the zoom process.
4. The zoom pinhole lens optical system according to claim 1, characterized in that: During the zoom process, the distance between the aperture and the CCD image plane remains unchanged.
5. The zoom pinhole lens optical system according to claim 1, characterized in that: All lenses are standard spherical.
6. An imaging method of a variable focal length pinhole lens optical system according to any one of claims 1 to 5, characterized in that: Proceed in the following steps: the light passes from left to right through the aperture, crescent lens A1, crescent lens A2, crescent lens A3, biconvex lens B1, crescent lens B2, biconvex lens B3, crescent lens B4, biconcave lens C1, crescent lens C2, crescent lens C3, crescent lens C4, crescent lens C5, crescent lens C6, biconvex lens D1, crescent lens D2, and crescent lens D3, and then forms an image on the CCD.
Citation Information
Patent Citations
Zoom pinhole lens optical system
CN215340523U