A close-up focusing system and lens
By introducing a liquid lens into the close-up focusing system, the speed and lifespan issues of traditional mechanical focusing methods have been solved, achieving fast focusing and lightweight design, thus improving the lifespan and portability of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- IOIP CHINA CO LTD
- Filing Date
- 2025-06-25
- Publication Date
- 2026-07-03
AI Technical Summary
Traditional optical systems suffer from problems such as slow response speed, high energy consumption, and short lifespan due to wear and tear of mechanical parts when focusing at close range.
A close-up focusing system is adopted, which includes a first lens, a first cemented plate, a liquid lens, a second lens, a third lens, and a second cemented plate. Fast focusing is achieved by adjusting the driving voltage of the liquid lens, avoiding mechanical movement.
It achieves rapid focusing, reduces mechanical wear, lowers energy consumption, and improves the lifespan and portability of the equipment.
Smart Images
Figure CN224457129U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical imaging technology, and in particular to a close-up focusing system and lens. Background Technology
[0002] Close-up photography requires achieving sharp images at short object distances and high optical magnification, which poses challenges to the focusing mechanism and response speed of the focusing system. Traditional optical systems mostly use mechanical focusing methods. In close-up photography, the mechanical structure must overcome inertia to move the lens group, which not only has problems with speed bottlenecks and high energy consumption, but also, in high-frequency focusing scenarios in close-up photography, mechanical components such as gears and guide rails are prone to wear due to friction, leading to a reduction in lifespan. Utility Model Content
[0003] This invention aims to overcome the problems of slow response speed, high energy consumption and short lifespan of existing focusing systems, and provides a close-up focusing system and lens.
[0004] To achieve the above objectives, the present invention provides a close-up focusing system, comprising a first lens, a first cemented film, a liquid lens, a second lens, a third lens, and a second cemented film, wherein the first lens, the first cemented film, the liquid lens, the second lens, the third lens, and the second cemented film are arranged sequentially along the optical axis from the object plane side to the image plane side.
[0005] In one embodiment, the optical distance between the first lens and the first adhesive sheet is between 1.13 mm and 1.17 mm, the optical distance between the first adhesive sheet and the liquid lens is between 2.98 mm and 3.02 mm, the optical distance between the liquid lens and the second lens is between 3.98 mm and 4.02 mm, the optical distance between the second lens and the third lens is between 0.08 mm and 0.12 mm, and the optical distance between the third lens and the second adhesive sheet is between 14.28 mm and 14.32 mm.
[0006] In one embodiment, the focal length of the first lens is 31.17 mm, the focal length of the first cemented sheet is 49.134 mm, the focal length of the second lens is 25.921 mm, the focal length of the third lens is -14.951 mm, and the focal length of the second cemented sheet is -41.50 mm.
[0007] In one embodiment, the first cemented sheet includes a first cemented lens and a second cemented lens, the first cemented lens being located on the object plane side of the second cemented lens; the second cemented sheet includes a third cemented lens and a fourth cemented lens, the third cemented lens being located on the object plane side of the fourth cemented lens.
[0008] In one embodiment, the object plane of the first lens is a convex spherical surface, and the image plane of the first lens is a concave spherical surface; the object plane of the first cemented lens is a convex spherical surface, and the image plane of the first cemented lens is a concave spherical surface; the object plane of the second cemented lens is a convex spherical surface, and the image plane of the second cemented lens is a concave spherical surface; the object plane of the second lens is a concave spherical surface, and the image plane of the second lens is a plane; the object plane of the third lens is a concave spherical surface, and the image plane of the third cemented lens is a convex spherical surface; the object plane of the third cemented lens is a concave spherical surface, and the image plane of the third cemented lens is a concave spherical surface; the object plane of the fourth cemented lens is a convex spherical surface, and the image plane of the fourth cemented lens is a convex spherical surface.
[0009] In one embodiment, the object plane radius of curvature of the first lens is 50 mm, and the image plane radius of curvature of the first lens is 80 mm; the object plane radius of curvature of the first cemented lens is 20 mm, and the image plane radius of curvature of the first cemented lens is 5 mm; the object plane curvature of the second cemented lens is the same as the image plane curvature of the first cemented lens, and the image plane radius of curvature of the second cemented lens is 8 mm; the object plane radius of curvature of the second lens is -10 mm, and the image plane radius of curvature of the second lens is ∞; the object plane radius of curvature of the third lens is 5 mm, and the image plane radius of curvature of the third lens is -40 mm; the object plane radius of curvature of the third cemented lens is -10 mm, and the image plane radius of curvature of the third cemented lens is 32 mm; the object plane curvature of the fourth cemented lens is the same as the image plane curvature of the third cemented lens, and the image plane radius of curvature of the fourth cemented lens is -15 mm.
[0010] In one embodiment, the center thickness of the first lens is between 0.78mm and 0.82mm, the center thickness of the first cemented lens is between 1.98mm and 2.02mm, the center thickness of the second cemented lens is between 0.78mm and 0.82mm, the center thickness of the third lens is between 1.18mm and 1.22mm, the center thickness of the third lens is between 0.98mm and 1.02mm, the center thickness of the third cemented lens is between 1.48mm and 1.52mm, and the center thickness of the fourth cemented lens is between 1.98mm and 2.02mm.
[0011] In one embodiment, the first lens and the first cemented lens are made of lanthanum flint glass, the second cemented lens and the third lens are made of crown glass, the second lens is made of heavy crown glass, the third cemented lens is made of barium crown glass, and the fourth cemented lens is made of flint glass.
[0012] In one embodiment, the close-up focusing system further includes an aperture stop, which is located in the same position as the liquid lens.
[0013] This invention also provides a lens, which includes the close-up focusing system described above.
[0014] In summary, this invention provides a close-up focusing system and lens. By placing a liquid lens between the first lens, the first cemented sheet, the second lens, the third lens, and the second cemented sheet, this invention achieves rapid focusing at a shorter object distance, meeting the high-speed requirements of modern close-up photography. Simultaneously, the use of the liquid lens makes the lens lighter, optimizing portability, and avoiding the physical and energy losses and mechanical deformation of traditional mechanical modules, thus improving the lifespan of the device.
[0015] To make the above-mentioned features and advantages of the utility model more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the close-up focusing system in this utility model.
[0017] Figure 2 This is a fan-shaped diagram of the close-up focusing system of this utility model in different fields of view at working wavelengths of 486nm, 588nm and 656nm.
[0018] Figure 3 The field curvature diagrams of the close-up focusing system of this utility model at operating wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm are shown.
[0019] Figure 4 This is a field curvature distortion diagram of the close-up focusing system of this utility model at working wavelengths of 486.1nm, 587.6nm and 656.3nm.
[0020] Figure 5 The graph shows the modulation transfer function of the close-up focusing system in this invention within the operating wavelength range (486.1nm-656.3nm).
[0021] Figure 6 This is a relative illumination diagram of the close-up focusing system of this utility model at a working wavelength of 587.6nm.
[0022] Figure 7 The diagram shows the circle of confusion of the close-up focusing system of this invention at working wavelengths of 486.1nm, 587.6nm, and 656.3nm.
[0023] Figure label:
[0024] First lens-1; First cemented sheet-2; Liquid lens-3; Second lens-4; Third lens-5; Second cemented sheet-6; Aperture stop-7;
[0025] First cemented lens - 21; Second cemented lens - 22; Third cemented lens - 61; Fourth cemented lens - 62. Detailed Implementation
[0026] To make the objectives and technical solutions of the present utility model clearer, the technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.
[0027] To address the challenges of focusing systems in close-up photography, including mechanical wear, focusing response speed, and high power consumption, and to avoid the shortcomings of mechanical focusing in close-up photography, this invention proposes a close-up focusing system and lens. In this invention, the surface of each lens closest to the focusing object plane is defined as the "object plane," and the surface of each lens closest to the imaging plane is defined as the "image plane." Figure 1 This is a schematic diagram of the optical path structure of the close-up focusing system in this utility model, as shown below. Figure 1 As shown, the focusing surface A of the close-up focusing system is on the left, with an initial focusing distance of 30mm; the imaging surface B is on the right, with an image distance of 6mm.
[0028] The close-up focusing system includes a lens, a liquid lens, and an aperture stop, which are arranged in sequence with the optical axis as the center of rotation. Specifically, the close-up focusing system includes a first lens 1, a first cemented plate 2, a liquid lens 3, an aperture stop 7, a second lens 4, a third lens 5, and a second cemented plate 6. From the object plane side to the image plane side, the first lens 1, the first cemented plate 2, the liquid lens 3, the aperture stop 7, the second lens 4, the third lens 5, and the second cemented plate 6 are arranged sequentially along the optical axis. The first cemented plate 2 includes a first cemented lens 21 and a second cemented lens 22, with the first cemented lens 21 located on the object plane side of the second cemented lens 22. The second cemented plate 6 includes a third cemented lens 61 and a fourth cemented lens 62, with the third cemented lens 61 located on the object plane side of the fourth cemented lens 62.
[0029] The total optical length of the close-up focusing system, i.e., the total optical length from object plane A to image plane B, is 70 mm. The optical distance between the first lens 1 and the first cemented sheet 2 can be between 1.13 mm and 1.17 mm, preferably 1.15 mm; the optical distance between the first cemented sheet 2 and the liquid lens 3 can be between 2.98 mm and 3.02 mm, preferably 3.00 mm; the liquid lens 3 and the aperture stop 7 can be in the same position; the optical distance between the liquid lens 3 and the second lens 4 can be between 3.98 mm and 4.02 mm, preferably 4.00 mm; the optical distance between the second lens 4 and the third lens 5 can be between 0.08 mm and 0.12 mm, preferably 0.10 mm; and the optical distance between the third lens 5 and the second cemented sheet 6 can be between 14.28 mm and 14.32 mm, preferably 14.30 mm.
[0030] Each lens group can be made of Chengdu Guangming colorless glass. Specifically, the first lens 1 is made of lanthanum flint glass (h-laf3b); the first cemented lens 21 is made of lanthanum flint glass (h-laf3b); the second cemented lens 22 is made of crown glass (h-k9l); the second lens 4 is made of heavy crown glass (h-zk3); the third lens 5 is made of crown glass (h-k9l); the third cemented lens 61 is made of barium crown glass (h-bak7); and the fourth cemented lens 62 is made of flint glass (h-f4). The liquid lens 3 is Corning-A39H.
[0031] The focal length of the first lens 1 is 31.17 mm, the focal length of the first cemented sheet 2 is 49.134 mm, the focal length of the second lens 4 is 25.921 mm, the focal length of the third lens 5 is -14.951 mm, and the focal length of the second cemented sheet 6 is -41.50 mm.
[0032] Furthermore, the curvature of the left side of each lens is defined as the object surface curvature of the lens, and the curvature of the right side is defined as the image surface curvature. The curvature is positive when the convex surface faces the focusing object surface A, and negative when the convex surface faces the imaging surface B.
[0033] The object plane of the first lens 1 is a convex spherical surface with a radius of curvature of 50 mm, and the image plane of the first lens 1 is a concave spherical surface with a radius of curvature of 80 mm. The object plane of the first cemented lens 21 is a convex spherical surface with a radius of curvature of 20 mm, and the image plane of the first cemented lens 21 is a concave spherical surface with a radius of curvature of 5 mm. The object plane of the second cemented lens 22 is a convex spherical surface with the same curvature as the image plane of the first cemented lens 21, and the image plane of the second cemented lens 22 is a concave spherical surface with a radius of curvature of 8 mm. The object plane of the second lens 4 is a concave spherical surface with a radius of curvature of -10 mm. The second lens 4 has a planar image plane with an image plane radius of curvature of ∞; the third lens 5 has a concave spherical object plane with an object plane radius of curvature of 5 mm and an image plane with a convex spherical object plane with an image plane radius of curvature of -40 mm; the third cemented lens has a concave spherical object plane with an object plane radius of curvature of -10 mm and an image plane with a concave spherical object plane with an image plane radius of curvature of 32 mm; the fourth cemented lens 62 has a convex spherical object plane with the same object plane curvature as the image plane curvature of the third cemented lens 61, and an image plane with a convex spherical object plane with an image plane radius of curvature of -15 mm. The surface profile tolerance for all curvatures is f / 3-5, with a local f / 3-0.5 tolerance (detected using an interferometer).
[0034] The center thickness of the first lens 1 can be between 0.78mm and 0.82mm, preferably 0.80mm; the center thickness of the first cemented lens 21 can be between 1.98mm and 2.02mm, preferably 2.00mm; the center thickness of the second cemented lens 22 can be between 0.78mm and 0.82mm, preferably 0.80mm; the center thickness of the second lens 4 can be between 1.18mm and 1.22mm, preferably 1.20mm; the center thickness of the third lens 5 can be between 0.98mm and 1.02mm, preferably 1.00mm; the center thickness of the third cemented lens 61 can be between 1.48mm and 1.52mm, preferably 1.50mm; and the center thickness of the fourth cemented lens 62 can be between 1.98mm and 2.02mm, preferably 2.00mm. It should be noted that the shape parameters of each lens can be flexibly adjusted as needed and are not limited to the parameters listed above.
[0035] The close-up focusing system operates at a focusing distance of 25mm-35mm, has an optical magnification of 1.868, a system aperture of F#9, and an imaging plane diameter of 6.8mm. The close-up focusing system operates in a visible light environment, with a working wavelength of 486nm-650nm.
[0036] Furthermore, this utility model also provides a lens, which includes the close-up focusing system described above. The specific structure of the close-up focusing system can be found in the above description. The lens can be used to observe surface features of printed materials, surface features of medical aesthetic skin, surface textures of cultural relics, and detailed features of precision instruments.
[0037] As shown in Table 1, the close-up focusing system changes its diopter by adjusting the driving voltage of the liquid lens 3, thereby changing the focusing distance of the close-up focusing system. Specifically, the correspondence between the voltage and diopter of the liquid lens 3 and the focusing distance of the close-up focusing system can be found in Table 1.
[0038]
[0039] Figure 2 The diagram shows the light fan patterns of the close-up focusing system in different fields of view at operating wavelengths of 486nm, 588nm, and 656nm. In the light fan patterns, the X-axis represents the position of the entrance pupil, and the Y-axis represents the deviation from the position of the principal ray transmitted onto the imaging plane. Figure 2 The set of aberrations generated by different fields of view is shown, and the difference between meridional and sagittal aberrations can be seen in each field of view.
[0040] Figure 3 The field curves of the close-up focusing system described in this utility model are shown at working wavelengths of 486.1nm, 587.6nm, and 656.3nm. Figure 3 Different curves represent different wavelengths. It can be seen that the image plane curvature is controlled within ±0.0872mm, which is negligible. This indicates that the field curvature correction of the close-up focusing system described in this embodiment is good.
[0041] Figure 4 This figure shows the distortion of the close-up focusing system described in this invention at operating wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm. The horizontal axis represents the magnitude of distortion, the vertical axis represents the field of view, and the curves represent the F-Tan(θ) distortion corresponding to different wavelengths of light at different fields of view on the image plane. Figure 4 As can be seen, within the entire field of view of the close-up focusing system, the distortion is controlled within ±0.2241%, and the position of the largest distortion occurs at the edge of the entire image field of view, indicating that the distortion of the close-up focusing system is well corrected.
[0042] Figure 5This is a graph showing the modulation transfer function (MTF) of the close-up focusing system described in this invention within the operating wavelength range (486.1nm-656.3nm). The image modulation of the lens at different spatial frequencies in the meridional or sagittal planes under each field of view is represented by the horizontal axis (spatial frequency) and the vertical axis (OTF modulus). Different lines represent different fields of view and differences in meridional or sagittal planes. Figure 5 It is indicated that, within the range of 0 to 130 cycles / mm, the optical modulation transfer function curves from the center to the edge of the field of view are relatively concentrated and all show a uniform and smooth downward trend. At the same time, the close-up focusing system has good imaging quality and good detail resolution in both high-frequency and low-frequency conditions.
[0043] Figure 6 This is a relative illumination diagram of the close-up focusing system described in this utility model at a working wavelength of 587.6nm. The horizontal axis represents the field of view, and the vertical axis represents the relative illumination. Figure 6 This indicates the illumination distribution in different areas of the imaging surface after light passes through the close-up focusing system, reflecting the attenuation of illuminance in different fields of view. From Figure 6 As can be seen, the image illuminance at the edge can reach more than 95% of the illuminance at the center, and the image illuminance is almost attenuated.
[0044] Figure 7 The diagram shows the circle of confusion of the close-up focusing system described in this invention at working wavelengths of 486.1 nm, 587.6 nm, and 656.3 nm. Figure 7 This illustrates the diffusion of all entrance pupil rays converging onto the image plane in different visual regions; different curves represent different wavelengths. From Figure 7 It can be seen that the geometric blur radius of almost all fields of view within the design wavelength range can converge to within the Airy disk, indicating that the aberration correction of the close-up focusing system is good.
[0045] In summary, this invention provides a close-up focusing system and lens. By placing a liquid lens 3 between the first lens 1, the first cemented sheet 2, the second lens 4, the third lens 5, and the second cemented sheet 6, this invention achieves rapid focusing at a shorter object distance, meeting the high-speed requirements of modern close-up photography. Simultaneously, the use of the liquid lens 3 makes the lens lighter, optimizing portability, and avoiding the physical and energy losses and mechanical deformation of traditional mechanical modules, thus improving the lifespan of the device.
[0046] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.
Claims
1. A close-up focusing system, characterized by comprising: It includes a first lens, a first cemented sheet, a liquid lens, a second lens, a third lens, and a second cemented sheet, arranged sequentially along the optical axis from the object plane side to the image plane side.
2. A close focus system as claimed in claim 1, characterized in that The optical spacing between the first lens and the first cemented sheet is between 1.13mm and 1.17mm, the optical spacing between the first cemented sheet and the liquid lens is between 2.98mm and 3.02mm, the optical spacing between the liquid lens and the second lens is between 3.98mm and 4.02mm, the optical spacing between the second lens and the third lens is between 0.08mm and 0.12mm, and the optical spacing between the third lens and the second cemented sheet is between 14.28mm and 14.32mm.
3. A close focus system as claimed in claim 2, characterized in that The focal length of the first lens is 31.17 mm, the focal length of the first cemented sheet is 49.134 mm, the focal length of the second lens is 25.921 mm, the focal length of the third lens is -14.951 mm, and the focal length of the second cemented sheet is -41.50 mm.
4. A close focus system as claimed in claim 1, characterized in that The first cemented sheet includes a first cemented lens and a second cemented lens, with the first cemented lens located on the object plane side of the second cemented lens; the second cemented sheet includes a third cemented lens and a fourth cemented lens, with the third cemented lens located on the object plane side of the fourth cemented lens.
5. A close focus system as claimed in claim 4, characterized in that The object plane of the first lens is a convex spherical surface, and the image plane of the first lens is a concave spherical surface; the object plane of the first cemented lens is a convex spherical surface, and the image plane of the first cemented lens is a concave spherical surface; the object plane of the second cemented lens is a convex spherical surface, and the image plane of the second cemented lens is a concave spherical surface; the object plane of the second lens is a concave spherical surface, and the image plane of the second lens is a plane; the object plane of the third lens is a concave spherical surface, and the image plane of the third cemented lens is a convex spherical surface; the object plane of the third cemented lens is a concave spherical surface, and the image plane of the third cemented lens is a concave spherical surface; the object plane of the fourth cemented lens is a convex spherical surface, and the image plane of the fourth cemented lens is a convex spherical surface.
6. A close focus system as claimed in claim 5, characterized in that The first lens has an object plane radius of curvature of 50 mm and an image plane radius of curvature of 80 mm; the first cemented lens has an object plane radius of curvature of 20 mm and an image plane radius of curvature of 5 mm; the second cemented lens has the same object plane curvature as the first cemented lens and an image plane radius of curvature of 8 mm; the second lens has an object plane radius of curvature of -10 mm and an image plane radius of curvature of ∞; the third lens has an object plane radius of curvature of 5 mm and an image plane radius of curvature of -40 mm; the third cemented lens has an object plane radius of curvature of -10 mm and an image plane radius of curvature of 32 mm; the fourth cemented lens has the same object plane curvature as the third cemented lens and an image plane radius of curvature of -15 mm.
7. A close focus system as claimed in claim 6, characterized in that The center thickness of the first lens is between 0.78mm and 0.82mm, the center thickness of the first cemented lens is between 1.98mm and 2.02mm, the center thickness of the second cemented lens is between 0.78mm and 0.82mm, the center thickness of the second lens is between 1.18mm and 1.22mm, the center thickness of the third lens is between 0.98mm and 1.02mm, the center thickness of the third cemented lens is between 1.48mm and 1.52mm, and the center thickness of the fourth cemented lens is between 1.98mm and 2.02mm.
8. A close focus system as claimed in claim 4, wherein, The first lens and the first cemented lens are made of lanthanum flint glass, the second cemented lens and the third lens are made of crown glass, the second lens is made of heavy crown glass, the third cemented lens is made of barium crown glass, and the fourth cemented lens is made of flint glass.
9. A close focus system as claimed in claim 1, wherein, The close-up focusing system also includes an aperture stop, which is located in the same position as the liquid lens.
10. A lens characterized by comprising: The lens includes a close-up focusing system as described in any one of claims 1-9.