Optical lens and system

Abstract

The utility model discloses an optical lens and a system. The optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged along the same optical axis in the light incidence direction. The focal power of each lens and the focal power of the optical lens meet a certain proportion, various aberrations of an optical system can be corrected, and meanwhile, the lenses are made of optical materials, including radiation-resistant optical materials, with the refractive index matched with the chromatic aberration, so that the influence of space radiation on the optical lens can be reduced while the imaging quality is improved.

Description

Technical Field

[0001] This utility model relates to the field of optomechanical design technology, and in particular to an optical lens and system. Background Technology

[0002] In applications such as deep space exploration and satellite positioning and navigation, star sensors play a crucial role in acquiring attitude information of spacecraft. The lens is a vital component of the star sensor for acquiring stellar images, and its quality directly impacts the sensor's performance. Furthermore, the effects of electrons, gamma rays, and ultraviolet radiation from space radiation on the transmittance of optical glass materials can degrade lens performance.

[0003] For spacecraft, due to the complex space environment and severe space light radiation, optical components and star sensors experience temperature differences due to space light radiation. At the same time, space light radiation corrodes optical glass materials, causing the color transmittance of the optical glass of star sensors exposed to long-term radiation to decrease, the lens to defocus, and further degrade the quality of the optical system, making it unable to work properly. Utility Model Content

[0004] The main purpose of this invention is to propose an optical lens and system that can effectively reduce the impact of space radiation on the optical system while ensuring imaging accuracy.

[0005] The technical solution adopted in this utility model is: an optical lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis in the direction of light incidence; wherein:

[0006] The ratio of the optical power ψ1 of the first lens to the optical power ψ of the optical lens satisfies 0.45≤ψ1 / ψ≤0.55; the ratio of the optical power ψ2 of the second lens to the optical power ψ of the optical lens satisfies 0.9≤ψ2 / ψ≤0.98; the ratio of the optical power ψ3 of the third lens to the optical power ψ of the optical lens satisfies -1.55≤ψ3 / ψ≤-1.48; the ratio of the optical power ψ4 of the fourth lens to the optical power ψ of the optical lens satisfies 0.9≤ψ4 / ψ≤0.96; the ratio of the optical power ψ5 of the fifth lens to the optical power ψ of the optical lens satisfies 1.3≤ψ5 / ψ≤1.35; and the ratio of the optical power ψ6 of the sixth lens to the optical power ψ of the optical lens satisfies -1.6≤ψ6 / ψ≤-1.45.

[0007] According to the above technical solution, the first lens is a radiation-resistant lens.

[0008] According to the above technical solution, the first lens has a refractive index of 1.5168 and a dispersion of 64.2; the second lens has a refractive index of 1.4378 and a dispersion of 94.52; the third lens has a refractive index of 1.7495 and a dispersion of 34.99; the fourth lens has a refractive index of 1.5928 and a dispersion of 68.34; the fifth lens has a refractive index of 1.883 and a dispersion of 40.85; and the sixth lens has a refractive index of 1.7407 and a dispersion of 27.76.

[0009] According to the above technical solution, along the direction of light incidence along the optical axis, the front surface of the first lens is a convex surface with a radius of curvature of 20.99, and the rear surface is a flat surface; the front surface of the second lens is a convex surface with a radius of curvature of 9.31, and the rear surface is a concave surface with a radius of curvature of 24.55; the front surface of the third lens is a concave surface with a radius of curvature of -39.17, and the rear surface is a concave surface with a radius of curvature of 13.35; the front surface of the fourth lens is a convex surface with a radius of curvature of 50.12, and the rear surface is a convex surface with a radius of curvature of -16.444; the front surface of the fifth lens is a convex surface with a radius of curvature of 13.366, and the rear surface is a flat surface; the front surface of the sixth lens is a concave surface with a radius of curvature of -19.893, and the rear surface is a concave surface with a radius of curvature of 19.85.

[0010] According to the above technical solution, the center thickness of the first lens is 4mm; the center thickness of the second lens is 3.2mm; the center thickness of the third lens is 1.9mm; the center thickness of the fourth lens is 3.3mm; the center thickness of the fifth lens is 1.6mm; and the center thickness of the sixth lens is 1.6mm.

[0011] According to the above technical solution, the light transmission aperture of the first lens is 11mm; the light transmission aperture of the second lens is 11mm; the light transmission aperture of the third lens is 10.2mm; the light transmission aperture of the fourth lens is 11mm; the light transmission aperture of the fifth lens is 11mm; and the light transmission aperture of the sixth lens is 8.9mm.

[0012] According to the above technical solution, along the direction of light incident along the optical axis, the distance between the rear surface of the first lens and the front surface of the second lens is 0.15mm; the distance between the rear surface of the second lens and the front surface of the third lens is 1.93mm; the distance between the rear surface of the third lens and the front surface of the fourth lens is 3.25mm; the distance between the rear surface of the fourth lens and the front surface of the fifth lens is 0.15mm; and the distance between the rear surface of the fifth lens and the front surface of the sixth lens is 1.5mm.

[0013] According to the above technical solution, the optical lens has a focal length of 20mm, a relative aperture of 1.8, a field of view of 200°, a light spectrum range of 450nm~850nm, and an optical length of less than or equal to 30mm.

[0014] According to the above technical solution, the optical lens includes a mechanical structure for fixing each lens.

[0015] Another aspect of this utility model provides an optical system, which includes the aforementioned optical lens, image plane and aperture stop, wherein the aperture stop is located on the front surface of the first lens in the optical lens along the direction of light incidence along the optical axis.

[0016] The beneficial effects of this invention are: this invention provides an optical lens and system, wherein the optical lens includes a lens group, and the optical power of each lens satisfies a certain proportion to the optical power of the optical lens, thereby eliminating various aberrations of the optical lens.

[0017] Furthermore, this invention incorporates a radiation-resistant lens as the first lens through which light enters, thereby reducing the impact of spatial radiation on the optical lens.

[0018] Furthermore, this invention incorporates multiple lenses with matched refractive indices and dispersions, thereby improving the imaging quality of the optical lens.

[0019] Furthermore, this invention designs the surface curvature radius, center thickness, light-transmitting aperture, and distance between each lens in the optical lens, so that the optical lens can better meet the thermal difference conditions, reduce the impact of temperature difference on the imaging of the optical lens, and achieve a heatless design.

[0020] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the optical lens structure according to an embodiment of the present invention;

[0023] Figure 2 This is a graph showing the energy circle radius curves of the optical system of this utility model at different field angles at 20°C.

[0024] Figure 3 This is a graph showing the energy circle radius curves of the optical system of this utility model at different field angles at -45°C.

[0025] Figure 4 This is a graph showing the energy circle radius curves of the optical system of this utility model at different field angles under 65°C.

[0026] Figure 5 This is a graph showing the percentage distortion of different wavelengths of light at 20°C as a function of the normalized field of view in the optical system of this utility model embodiment.

[0027] Figure 6 This is a chromatic aberration curve of the optical system of this utility model embodiment as a function of the field of view at 20°C.

[0028] Reference numerals in the attached figures: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Image plane; 8. Aperture stop. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0030] It should be noted that the illustrations provided in the embodiments of this utility model are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0031] In this utility model, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0032] Example 1

[0033] This embodiment provides an optical lens, including a lens group. The lens group includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6, with each lens arranged sequentially along the optical axis in the direction of light incidence.

[0034] To eliminate optical lens aberrations, this embodiment rationally allocates the optical power of each lens so that each lens satisfies a certain proportion to the overall optical power ψ of the optical lens. The optical power ψ0 of each lens is calculated as follows: ψ0 = (n' - n) / r = n' / f' = -n / f, where n' is the image-side refractive index of the lens, n is the object-side refractive index of the lens, r is the radius of the spherical surface, f' is the image focal length, and f is the object focal length.

[0035] The ratio of the optical power ψ1 of the first lens 1 to the optical power ψ of the optical lens satisfies 0.45≤ψ1 / ψ≤0.55.

[0036] The ratio of the optical power ψ2 of the second lens 2 to the optical power ψ of the optical lens satisfies 0.9≤ψ2 / ψ≤0.98.

[0037] The ratio of the optical power ψ3 of the third lens 3 to the optical power ψ of the optical lens satisfies -1.55≤ψ3 / ψ≤-1.48.

[0038] The ratio of the optical power ψ4 of the fourth lens 4 to the optical power ψ of the optical lens satisfies 0.9≤ψ4 / ψ≤0.96.

[0039] The ratio of the optical power ψ5 of the fifth lens 5 to the optical power ψ of the optical lens satisfies 1.3≤ψ5 / ψ≤1.35.

[0040] The ratio of the optical power ψ6 of the sixth lens 6 to the optical power ψ of the optical lens satisfies -1.6≤ψ6 / ψ≤-1.45.

[0041] Furthermore, in this embodiment, the first lens 1 is configured as a radiation-resistant lens to reduce spatial radiation entering the lens group.

[0042] Furthermore, to optimize the imaging effect, this embodiment selects glass materials with different refractive indices and dispersions as lens materials, wherein:

[0043] The first lens 1 has a refractive index of 1.5168 and a dispersion of 64.2. In this embodiment, radiation-resistant glass K709 is selected, which can reduce the influence of space radiation on the optical lens.

[0044] The second lens 2 has a refractive index of 1.4378 and a dispersion of 94.52. In this embodiment, H-FK95N glass is selected.

[0045] The third lens 3 has a refractive index of 1.7495 and a dispersion of 34.99. In this embodiment, H-LAF4GT glass is used.

[0046] The fourth lens 4 has a refractive index of 1.5928 and a dispersion of 68.34. In this embodiment, H-ZPK5 glass is selected.

[0047] The fifth lens 5 has a refractive index of 1.883 and a dispersion of 40.85. In this embodiment, H-ZLAF68C glass is used.

[0048] The sixth lens 6 has a refractive index of 1.7407 and a dispersion of 27.76. In this embodiment, H-ZF50 glass is selected.

[0049] Furthermore, in order to achieve athermalization of the optical lens while eliminating aberrations, the athermalization condition also needs to be met. That is, based on aberration theory and the design principle of athermalized optics, chromatic aberration, secondary spectrum, and thermal aberration corrections must be achieved simultaneously. Based on the above theory, the following mathematical model is established in this embodiment:

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] in, The total optical power of the optical lens; Let i be the number of lenses in the optical lens; i indicates that the lens is the 6th lens arranged along the incident direction of the optical axis in the optical lens. Block lens; For the first Optical power of a block lens; For paraxial rays to pass through the first The height of the block lens; This is the front focal length of the optical system. This is the back focal length of the optical system; The focal length of the optical system; and For the first The normalization coefficient of the block lens in the operating wavelength band. For the first Thermal coefficient of the block lens; For the first The refractive index of the material of the block lens; For the first The coefficient of thermal expansion of the material used in the block lens.

[0056] Based on the above mathematical model, in order to ensure clear imaging of the optical lens within the operating temperature range of -45℃ to +65℃, other parameters of the optical lens in this embodiment are designed, including the radius of curvature of the front and rear surfaces of each lens in the lens group, the center thickness, the aperture, and the distance between each lens, wherein:

[0057] The first lens 1 is a plano-convex lens, with its object side being a convex surface with a radius of curvature of 20.99, its image side being a plane, its center thickness being 4mm, and its light-transmitting aperture being 11mm.

[0058] The second lens 2 is a meniscus lens, with its object side being a convex surface with a radius of curvature of 9.31 and its image side being a concave surface with a radius of curvature of 24.55. Its center thickness is 3.2 mm and its light-transmitting aperture is 11 mm.

[0059] The third lens 3 is a biconcave lens, with its object side being a concave surface with a radius of curvature of -39.17 and its image side being a concave surface with a radius of curvature of 13.35. Its center thickness is 1.9 mm and its light-transmitting aperture is 10.2 mm.

[0060] The fourth lens 4 is a biconvex lens, with its object side being a convex surface with a radius of curvature of 50.12 and its image side being a convex surface with a radius of curvature of -16.444. Its center thickness is 3.3 mm and its light-transmitting aperture is 11 mm.

[0061] The fifth lens 5 is a plano-convex lens with a convex object side with a radius of curvature of 13.366, a flat image side, a central thickness of 1.6 mm, and a light-transmitting aperture of 11 mm.

[0062] The sixth lens 6 is a biconcave lens, with its object side being a concave surface with a radius of curvature of -19.893 and its image side being a concave surface with a radius of curvature of 19.85. Its center thickness is 1.6 mm and its light-transmitting aperture is 8.9 mm.

[0063] The image shown on the side of the image above is the final image formed by the optical lens.

[0064] Furthermore, the distances and positional relationships between the lenses are as follows: Figure 1 As shown: the distance between the first lens 1 and the second lens 2 along the optical axis is 0.15 mm; the distance between the second lens 2 and the third lens 3 along the optical axis is 1.93 mm; the distance between the third lens 3 and the fourth lens 4 along the optical axis is 3.25 mm; the distance between the fourth lens 4 and the fifth lens 5 along the optical axis is 0.15 mm; the distance between the fifth lens 5 and the sixth lens 6 along the optical axis is 1.5 mm. The above distances are the distances along the optical axis between the closest surfaces of the two lenses.

[0065] Furthermore, the optical lens in this embodiment is also provided with an aluminum alloy mechanical structure for fixing the lens group.

[0066] Based on the above design of the lens parameters in the lens group of the optical lens, this embodiment finally obtains an optical lens with a focal length of 20mm, a relative aperture of 1.8, a field of view of 200°, and an optical length of less than or equal to 30mm.

[0067] Example 2

[0068] This embodiment provides an optical system, the structure of which is as follows: Figure 1 As shown, it includes the optical lens, image plane 7 and aperture stop 8 described in Example 1.

[0069] The structure and optical parameters of the optical lens have been described in Example 1 and will not be repeated here.

[0070] The aperture stop 8 is located on the object side of the first lens 1 in the optical lens, and the image plane 7 is 5.4 mm away from the image side of the sixth lens 6 in the optical lens.

[0071] The imaging quality of the optical system in this embodiment was tested.

[0072] First, at 20℃, -45℃, and 65℃, different field of view angles were selected to measure the proportion of energy within the enclosing circle to the total energy of the energy circle as the radius of the enclosing circle increases, and the obtained test data were plotted as curves.

[0073] Among them, the energy circle radius curves at different field angles at 20℃ are as follows: Figure 2 As shown, the energy circle radius curves at different field of view angles at -45℃ are as follows: Figure 3 As shown, the energy circle radius curves at different field angles at 65℃ are as follows: Figure 4 As shown.

[0074] Observing the graph, data from different field angles at 20℃, -45℃, and 65℃ show that as the radius of the enclosing circle gradually increases and approaches the maximum radius of the energy circle (8),... The proportion of energy within the enclosing circle to the total energy of the energy circle gradually increases and approaches 1.0, indicating that the optical system of this embodiment has a high degree of concentration in imaging at operating temperatures of high temperature 65℃, normal temperature 20℃, and low temperature -45℃.

[0075] Next, the imaging accuracy of this optical system was tested. At 20°C, different field-of-view angles were selected, and the percentage of distortion in the image produced by the optical system was measured as the normalized field of view changed. The test data were then plotted as a curve, as shown below. Figure 5 As shown.

[0076] Observing the graphs, the data from different field angles show that as the normalized field of view increases, the percentage of distortion in images formed by different wavelengths of light is between 0.4% and 1.6%, indicating that the distortion in the images formed by this optical system is small and the imaging accuracy is high.

[0077] To further test the imaging accuracy of this optical system, the magnitude of the transverse chromatic aberration of the image formed by this optical system was measured at 20°C as the field of view increased, and the obtained data were plotted as a curve, as shown in the figure. Figure 6 As shown.

[0078] Observing the graphs, the data shows that as the field of view increases and eventually approaches 10°, the transverse chromatic aberration of the image formed by this optical system first increases and then decreases, with a maximum value of approximately 1.45. This indicates that the transverse chromatic aberration of the image produced by this optical system is small, resulting in high image sharpness.

[0079] Based on the above tests, the optical system of this embodiment has good light focusing effect at high temperature, normal temperature and low temperature, is suitable for spatial light radiation environment with temperature difference, and has high imaging quality.

[0080] In summary, this utility model provides an optical lens and system that rationally allocates the material and optical power of each lens in the lens, and designs the lens parameters according to the thermal difference conditions, which can effectively reduce various aberrations of the optical system, including chromatic aberration and distortion, and reduce the influence of spatial radiation light on the optical system.

[0081] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this utility model.

[0082] The order of the steps in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0083] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An optical lens characterized in that, Comprise first lens (1), second lens (2), third lens (3), fourth lens (4), fifth lens (5) and sixth lens (6) arranged in turn along the direction of light incidence of optical axis;Wherein: The ratio of the refractive power ψ1 of the first lens (1) and the refractive power ψ of the optical lens satisfies 0.45≤ψ1 / ψ≤0.55;The ratio of the refractive power ψ2 of the second lens (2) and the refractive power ψ of the optical lens satisfies 0.9≤ψ2 / ψ≤0.98;The ratio of the refractive power ψ3 of the third lens (3) and the refractive power ψ of the optical lens satisfies-1.55≤ψ3 / ψ≤-1.48;The ratio of the refractive power ψ4 of the fourth lens (4) and the refractive power ψ of the optical lens satisfies 0.9≤ψ4 / ψ≤0.96;The ratio of the refractive power ψ5 of the fifth lens (5) and the refractive power ψ of the optical lens satisfies 1.3≤ψ5 / ψ≤1.35;The ratio of the refractive power ψ6 of the sixth lens (6) and the refractive power ψ of the optical lens satisfies-1.6≤ψ6 / ψ≤-1.

45.

2. The optical lens of claim 1, wherein, The first lens (1) is a radiation resistant lens.

3. The optical lens of claim 1, wherein, The refractive index of the first lens (1) is 1.5168, and the dispersion is 64.2;The refractive index of the second lens (2) is 1.4378, and the dispersion is 94.52;The refractive index of the third lens (3) is 1.7495, and the dispersion is 34.99;The refractive index of the fourth lens (4) is 1.5928, and the dispersion is 68.34;The refractive index of the fifth lens (5) is 1.883, and the dispersion is 40.85;The refractive index of the sixth lens (6) is 1.7407, and the dispersion is 27.

76.

4. The optical lens of claim 1, wherein, In the direction of light incidence along the optical axis, the front surface of the first lens (1) is a convex surface with a curvature radius of 20.99, and the back surface is a plane;The front surface of the second lens (2) is a convex surface with a curvature radius of 9.31, and the back surface is a concave surface with a curvature radius of 24.55;The front surface of the third lens (3) is a concave surface with a curvature radius of-39.17, and the back surface is a concave surface with a curvature radius of 13.35;The front surface of the fourth lens (4) is a convex surface with a curvature radius of 50.12, and the back surface is a convex surface with a curvature radius of-16.444;The front surface of the fifth lens (5) is a convex surface with a curvature radius of 13.366, and the back surface is a plane;The front surface of the sixth lens (6) is a concave surface with a curvature radius of-19.893, and the back surface is a concave surface with a curvature radius of 19.

85.

5. The optical lens of claim 1, wherein, The center thickness of the first lens (1) is 4mm;The center thickness of the second lens (2) is 3.2mm;The center thickness of the third lens (3) is 1.9mm;The center thickness of the fourth lens (4) is 3.3mm;The center thickness of the fifth lens (5) is 1.6mm;The center thickness of the sixth lens (6) is 1.6mm.

6. The optical lens of claim 1, wherein, The first lens (1) has an aperture of 11 mm; the second lens (2) has an aperture of 11 mm; the third lens (3) has an aperture of 10.2 mm; the fourth lens (4) has an aperture of 11 mm; the fifth lens (5) has an aperture of 11 mm; and the sixth lens (6) has an aperture of 8.9 mm.

7. The optical lens of claim 1, wherein, In the direction of light ray incidence along the optical axis, the distance between the rear surface of the first lens (1) and the front surface of the second lens (2) is 0.15 mm; the distance between the rear surface of the second lens (2) and the front surface of the third lens (3) is 1.93 mm; the distance between the rear surface of the third lens (3) and the front surface of the fourth lens (4) is 3.25 mm; the distance between the rear surface of the fourth lens (4) and the front surface of the fifth lens (5) is 0.15 mm; and the distance between the rear surface of the fifth lens (5) and the front surface of the sixth lens (6) is 1.5 mm.

8. The optical lens of claim 1, wherein, The optical lens has a focal length of 20 mm, a relative aperture of 1.8, a field of view of 200°, a spectral range of 450 nm to 850 nm, and an optical length of less than or equal to 30 mm.

9. The optical lens of claim 1, wherein, The optical lens comprises a mechanical structure for fixing the lenses.

10. An optical system characterized by, The optical lens, the image plane (7), and the aperture stop (8) according to any one of claims 1-9, wherein the aperture stop (8) is located in front of the first lens (1) in the optical lens in the direction of light ray incidence along the optical axis.

Images