Starlight-level high-definition optical lens

Abstract

The application discloses a starlight-level high-definition optical lens and belongs to the technical field of optical lenses. The optical lens comprises a first lens, a diaphragm, a second lens, a third lens, a fourth lens and a photosensitive chip which are sequentially arranged along an optical axis from an object plane to an image plane. The first lens, the third lens and the fourth lens are plastic aspheric lenses, and the second lens is a glass spherical lens. The focal lengths of the first lens, the second lens, the third lens and the fourth lens are negative, positive, positive and negative in sequence. The optical lens has an FNo. of 1.6, a resolution of 80% of 4 million pixels or more, and the night vision is confocal and the purple light halo is weakened. Moreover, the optical lens has a low cost.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, specifically a starlight-level high-definition optical lens. Background Technology

[0002] With the development of 5G and the emergence of the Internet of Things (IoT), new industries have sprung up, such as intelligent sensors, mobile terminals, industrial systems, building control systems, smart home facilities, and video surveillance systems. Technological reforms in the security and medical fields, such as real-time online monitoring, location tracking, alarm linkage, dispatching and command, contingency plan management, remote control, security, remote maintenance, online upgrades, statistical reports, decision support, and management and service functions like a centralized Cockpit Dashboard, are also emerging. New technological demands are constantly appearing, with black-light-level high-definition lenses, infrared confocal lenses, cost reduction, and improved lens stability becoming increasingly sought-after goals. However, current optical lenses on the market have shortcomings in high and low temperature performance, night vision, and protection against purple halos, and are also relatively expensive. Summary of the Invention

[0003] In view of this, the present invention provides a starlight-level high-definition optical lens to address the shortcomings of the prior art.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a starlight-level high-definition optical lens, comprising a first lens, an aperture, a second lens, a third lens, a fourth lens, and a photosensitive chip arranged sequentially along the optical axis from the object plane to the image plane. The first lens, the third lens, and the fourth lens are all plastic aspherical lenses, and the second lens is a glass spherical lens. The focal lengths of the first lens, the second lens, the third lens, and the fourth lens are negative, positive, positive, and negative, respectively.

[0005] Furthermore, the first lens has a radius of curvature of 19.71 mm on the object plane side and 2.88 mm on the image plane side, a center thickness of 1.37 mm, and an air gap of 6.5 mm between it and the second lens; the first lens has a refractive index of 1.545 and a dispersion coefficient of 55.99.

[0006] Furthermore, the second lens has a radius of curvature of 11.95 mm on the object plane side and -8.91 mm on the image plane side, a center thickness of 2.52 mm, and an air gap of 2.94 mm between it and the third lens; the second lens has a refractive index of 1.593 and a dispersion coefficient of 68.63.

[0007] Furthermore, the radius of curvature of the third lens near the object plane is 4.54 mm, the radius of curvature near the image plane is -3.32 mm, the center thickness is 2.42 mm, and the air gap between it and the fourth lens is 0.14 mm; the refractive index of the third lens is 1.535, and the dispersion coefficient is 55.71.

[0008] Furthermore, the radius of curvature of the fourth lens near the object plane is -2.22 mm, the radius of curvature near the image plane is -8.34 mm, the center thickness is 0.76 mm, and the air gap between the fourth lens and the photosensitive chip is 5.13 mm; the refractive index of the fourth lens is 1.636, and the dispersion coefficient is 23.97.

[0009] Furthermore, the first lens is made of APL5014CL, the second lens is made of FK69, the third lens is made of K26R, and the fourth lens is made of EP5000.

[0010] Furthermore, the starlight-level high-definition optical lens has an FNo. of 1.6.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] 1) By using four lens elements and combining the parameter correction of plastic aspherical lenses with glass lenses, the lens still achieves an FNo. of 1.6, reaching starlight level, while reducing costs;

[0013] 2) Through precise coordination of structure and optics: 1. The use of plastic aspherical surfaces in the third and fourth lenses ensures controllable high and low temperature offsets, while the use of optical glass lenses in the second lens further adjusts the temperature drift, ensuring no temperature drift in the center field of view of the optical system; 2. By adjusting and changing the shape of the lenses, aberrations in high and low temperature states are corrected, ensuring clear imaging across the entire field of view of the optical system; achieving no defocusing at high and low temperatures (high temperature +80℃, low temperature -40℃);

[0014] 3) Through optical simulation and multiple adjustments to structural tolerances, the resolution is improved to 80%, reaching over 4 million pixels;

[0015] 4) By matching lens structure and selecting materials, night vision confocal focus and purple halo reduction are achieved. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0017] Figure 2 This is a chromatic aberration diagram according to an embodiment of the present invention;

[0018] Figure 3 This is a diagram showing the astigmatism and distortion curves of an embodiment of the present invention;

[0019] Figure 4 This is a vertical axis color difference curve diagram according to an embodiment of the present invention;

[0020] Figure 5 This is an MTF curve diagram of an embodiment of the present invention.

[0021] In the diagram: 1-first lens, 2-second lens, 3-third lens, 4-fourth lens, 5-aperture, 6-photosensitive chip. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0023] Example:

[0024] Reference Figure 1 The starlight-level high-definition optical lens includes a first lens 1, an aperture 5, a second lens 2, a third lens 3, a fourth lens 4, and a photosensitive chip 6 arranged sequentially along the optical axis from the object plane to the image plane. The first lens 1, the third lens 3, and the fourth lens 4 are all plastic aspherical lenses, and the second lens 2 is a glass spherical lens. The focal lengths of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 are negative, positive, positive, and negative, respectively.

[0025] The mirror parameters of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 are shown in the table below:

[0026] lens Surface serial number Surface type radius of curvature / mm Center thickness or air gap / mm Refractive index Dispersion coefficient Material First lens 1 even aspherical surface 19.71 1.37 1.545 55.99 APL5014CL 2 even aspherical surface 2.88 6.5 Second lens 3 spherical 11.95 2.52 1.593 68.63 FK69 4 spherical -8.91 2.94 Third lens 5 even aspherical surface 4.54 2.42 1.535 55.71 K26R 6 even aspherical surface -3.32 0.14 Fourth lens 7 even aspherical surface -2.22 0.76 1.636 23.97 EP5000 8 even aspherical surface -8.34 5.13

[0027] The aspherical coefficients of the first lens 1, the third lens 3, and the fourth lens 4 are shown in the table below:

[0028] Surface serial number k a2 a3 a4 a5 a6 a7 a8 1 -91.84 -2.31E-03 9.90E-05 -2.09E-06 1.71E-08 0.00E+00 0.00E+00 0.00E+00 2 -0.39 -4.79E-03 4.46E-04 -8.44E-05 9.28E-06 -3.98E-07 0.00E+00 0.00E+00 5 -16.4 1.95E-02 -4.25E-03 7.05E-04 -7.02E-05 2.14E-06 8.79E-08 -1.77E-08 6 0.026 1.57E-03 4.41E-03 -1.03E-03 1.35E-04 -1.29E-05 7.45E-07 -1.42E-08 7 -2.29 8.20E-03 8.74E-04 -2.08E-04 -3.47E-05 1.57E-05 -2.02E-06 1.00E-07 8 -8.61 2.20E-02 -4.35E-03 1.39E-03 -3.27E-04 4.43E-05 -2.47E-06 8.47E-09

[0029] Aspherical surfaces all satisfy the following equation:

[0030]

[0031] Where: c is the curvature corresponding to the radius, y is the radial coordinate, the unit of the radial coordinate is the same as the unit of the lens length, and k is the conic quadratic coefficient;

[0032] When k < -1, the surface profile of the lens is a hyperbola;

[0033] When k=-1, the surface profile of the lens is a parabola;

[0034] When -1 < k < 0, the surface curve of the lens is an ellipse;

[0035] When k=0, the surface profile of the lens is circular;

[0036] When k > 0, the surface curve of the lens is an oblate shape;

[0037] a2~a8 represent the coefficients corresponding to each radial coordinate.

[0038] Reference Figure 2 The spherical aberration is corrected to within ±0.02mm. The spherical aberration correction is better within the spectral bandwidth, which can increase the cleanliness of the actual image captured by the lens.

[0039] Reference Figure 3 Because of the use of glass aspherical lenses and high refractive index lenses, astigmatism and field curvature can be corrected to a suitable range, so that the resolving power in the meridional direction can be close to the resolving power in the sagittal direction.

[0040] Reference Figure 4 The relative chromatic aberration of f-ray, d-ray, and c-ray relative to the vertical axis is within 2μm, which can meet our lens resolution quality requirements.

[0041] Reference Figure 5 This lens has excellent resolution, and its spatial frequency of 160 cycles / mm provides high sharpness within the center field of view and the 0.7 field of view.

[0042] The technical effects and principles achieved by the starlight-level high-definition optical lens in this invention are as follows:

[0043] 1. Implement starlight function (FNo. reaches 1.6):

[0044] The increased aperture of the lens mainly leads to an increase in spherical aberration and coma. By using the aberrant dispersion coefficient material of the second lens (2), the spherical aberration and chromatic aberration of the optical system are reduced; the third lens (3) and the fourth lens (4) can effectively correct spherical aberration and coma by using aspherical lenses, resulting in smaller residual spherical aberration and coma of the lens.

[0045] 2. Achieve focus retention at high and low temperatures:

[0046] Based on a thorough understanding of optical glass materials, appropriate materials are selected for some positive and negative focal spherical lenses to control the temperature drift of the optical system within a reasonable range. At the same time, a stable mechanical structure is selected to cooperate with the use, thereby achieving focus stability at high and low temperatures.

[0047] 3. Achieve a resolution of over 4 million pixels:

[0048] By using the second lens (2) with an anomalous dispersion coefficient material, and the third lens (3) and the fourth lens (4) with aspherical lenses, spherical aberration and coma can be corrected very effectively, and residual aberrations of the optical system can be further corrected, thereby achieving ideal resolution.

[0049] 4. Achieve night vision confocal focus and purple halo requirements:

[0050] By using the second lens (2) with a material with large dispersion difference, the chromatic aberration is initially corrected. The first lens (1) uses a low dispersion material to further reduce the transverse chromatic aberration of the optical system. The third lens (3) and the fourth lens (4) use materials with large dispersion difference to further optimize the chromatic aberration, thereby ensuring that light of different wavelengths converges together.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the claims of the present invention.

Claims

1. A starlight-level high-definition optical lens, characterized in that: It consists of a first lens (1), an aperture (5), a second lens (2), a third lens (3), a fourth lens (4) and a photosensitive chip (6) arranged sequentially along the optical axis from the object plane to the image plane. The first lens (1), the third lens (3) and the fourth lens (4) are all plastic aspherical lenses, and the second lens (2) is a glass spherical lens. The focal lengths of the first lens (1), the second lens (2), the third lens (3) and the fourth lens (4) are negative, positive, positive and negative, respectively. The first lens (1) has a radius of curvature of 19.71 mm on the side near the object plane, a radius of curvature of 2.88 mm on the side near the image plane, a center thickness of 1.37 mm, and an air gap of 6.5 mm between it and the second lens (2). The first lens (1) has a refractive index of 1.545 and a dispersion coefficient of 55.

99. The second lens (2) has a radius of curvature of 11.95 mm on the side near the object plane, a radius of curvature of -8.91 mm on the side near the image plane, a center thickness of 2.52 mm, and an air gap of 2.94 mm between it and the third lens (3). The refractive index of the second lens (2) is 1.593, and the dispersion coefficient is 68.

63. The third lens (3) has a radius of curvature of 4.54 mm on the object side and -3.32 mm on the image side, a center thickness of 2.42 mm, and an air gap of 0.14 mm between it and the fourth lens (4); the refractive index of the third lens (3) is 1.535 and the dispersion coefficient is 55.

71. The fourth lens (4) has a radius of curvature of -2.22 mm on the object side and -8.34 mm on the image side, a center thickness of 0.76 mm, and an air gap of 5.13 mm between it and the photosensitive chip (6). The refractive index of the fourth lens (4) is 1.636 and the dispersion coefficient is 23.

97.

2. The starlight-level high-definition optical lens according to claim 1, characterized in that: The first lens (1) is made of APL5014CL, the second lens (2) is made of FK69, the third lens (3) is made of K26R, and the fourth lens (4) is made of EP5000.

3. The starlight-level high-definition optical lens according to claim 2, characterized in that: The starlight-level high-definition optical lens has an FNo. of 1.6.

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