An optical receiving device based on free-form surface

Abstract

The present invention belongs to the field of optical antenna technology, specifically an optical receiving device based on free-form surfaces. The optical receiving device of the present invention comprises a first positive lens, a negative lens, a second positive lens, an aperture, and an infrared filter coaxially fixed in a lens barrel in sequence; wherein the second surface type of the first positive lens and the first surface type of the second positive lens are eighth-order XY polynomial free-form surfaces; the total length L of the optical receiving device system is 18-22 mm, the relative illumination of the optical receiving surface is greater than 0.95, the full field of view angle W is 70-72°, the focal length f is 6.5-7.5 mm, and the optical gain is 11.5-13.5. The optical receiving device of the present invention adopts an XY polynomial free-form surface design, which realizes an optical receiving characteristic of a large field of view of 70-72° and a high gain of 11.5-13.5 while ensuring a compact structure and a small number of lenses, and the lenses are all made of optical plastic materials, which can greatly reduce the difficulty of processing and save processing costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical antennas, and in particular relates to an optical receiving device based on a free-form surface. Background Art

[0002] Compared with traditional lighting methods, light-emitting diodes (LEDs) have advantages such as low power consumption, high brightness and long life. They have been widely used in various fields such as information display, visual transmission, and lighting. Visible light communication technology is an emerging wireless communication technology that uses LED light-emitting devices to emit high-speed, bright and flashing light signals that are imperceptible to the human eye to achieve information transmission. Compared with traditional radio frequency communication and other optical wireless communication methods, visible light communication is not limited by bandwidth, is not subject to electromagnetic interference from electronic devices, has high security and confidentiality, and LED lighting communication equipment is easy to install, so it has great development potential.

[0003] In visible light communication systems, the main research areas currently include communication channel models, modulation and demodulation technology, and optimization of light source layout, but there is little research on visible light receiving technology. A receiving antenna with superior optical performance can effectively improve the optical receiving power, optical gain, and signal-to-noise ratio. In the research of optical receiving antennas, there is a problem that the optical gain decreases with the increase of the field of view. The industry at home and abroad has proposed various design ideas for optical antennas. The research work is mainly to propose new antenna structures. However, the research results published so far still have large spot sizes, low optical gain, and poor uniformity, making it difficult to effectively utilize light energy. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, an object of the present invention is to provide an optical receiving device based on a free-form surface with compact structure, high optical gain, large field of view and good channel performance.

[0005] The optical receiving device based on the free-form surface provided by the present invention has a structure as shown in Figure 1 As shown, XY polynomial free-form surfaces are introduced in the design process to achieve optical receiving characteristics with large field of view and high gain while ensuring a compact structure and a small number of lenses. All lenses are made of optical plastic materials, which greatly reduces the processing difficulty and saves processing costs.

[0006] The optical receiving device based on free-form surface provided by the present invention comprises: a first positive lens 1, a negative lens 2, a second positive lens 3, a lens barrel 4, an aperture 7, and an infrared filter 8; the first positive lens 1, the negative lens 2, the aperture 7, the second positive lens 3, and the infrared filter are coaxially fixed on the inner wall of the lens barrel 4 in sequence; the first positive lens 1 and the negative lens 2 are separated by a lens spacer 5, and the aperture 7 is fixed to the inner wall of the lens barrel 4 through an aperture spacer 6; wherein, the first positive lens 1 comprises a first surface 11 facing the object plane and a second surface 12 facing the receiving surface; the negative lens 2 comprises a third surface 21 facing the object plane and a fourth surface 22 facing the receiving surface; the second positive lens 3 comprises a fifth surface 31 facing the object plane and a sixth surface 32 facing the receiving surface.

[0007] Furthermore, the focal length of the first positive lens 1 is between 0.060 and 0.070 mm. -1 The first surface 11 is a convex spherical surface with a curvature radius between 10.866-11.066 mm; the second surface 12 is an XY polynomial free-form surface with a curvature radius between -27.690 and -27.890 mm; the center thickness of the first positive lens 1 is between 2.659 and 2.859 mm.

[0008] Furthermore, the focal length of the negative lens 2 is between -0.143 and -0.163 mm. -1 The third surface 21 is a concave spherical surface with a curvature radius between -6.602 and -6.802 mm; the fourth surface 22 is a concave spherical surface with a curvature radius between 6.315 and 6.515 mm; and the center thickness of the first negative lens 2 is between 1.014 and 1.214 mm.

[0009] Furthermore, the focal length of the second positive lens 3 is between 0.141 and 0.161 mm. -1 The fifth surface 31 is an XY polynomial free-form surface with a radius of curvature between 16.006 and 16.206 mm; the sixth surface 32 is a convex spherical surface with a radius of curvature between -4.001 and -4.201 mm; and the center thickness of the second positive lens 3 is between 3.853 and 4.053 mm.

[0010] Furthermore, the distance between the center of the second surface 12 and the center of the third surface 21 is between 0.665-0.865 mm; the distance between the center of the fourth surface 22 and the center of the aperture 7 is between 2.052-2.252 mm; the distance between the center of the aperture 7 and the center of the fifth surface 31 is between 1.373-1.573 mm.

[0011] Furthermore, the order of the XY polynomial self-surface is eight-order, and the equation is described as:

[0012]

[0013] in: c is the curvature, k is the conic section coefficient, and the subscript E is the polynomial coefficient.

[0014] Furthermore, the conic curve coefficient of the second surface 12 is between 1.067 and 1.267; the conic curve coefficient of the fifth surface 31 is between -20.581 and -20.781; in the XY polynomial of the second surface 12, X 2 The coefficient of the term is -8.440×10 0 —-8.640×10 0 Between, Y 2 The coefficient of the term is -7.400×10 -1 —-7.600×10 -1 Between, X 4 The coefficient of the term is -2.000×10 5 —-2.200×10 5 , Y 4 The coefficient of the term is 5.454×10 4 -5.654×10 4 Between, X 2 Y 2 The coefficient of the term is -4.940×10 2 —-5.140×10 2 Between, X 6 The coefficient of the term is -1.228×10 8 —-1.428×10 8 Between, X 4 Y 2 The coefficient of the term is -1.086×10 8 —-1.286×10 8 Between, X 2 Y 4 The coefficient of the term is 7.982×10 7 -8.182×10 7 Between, Y 6 The coefficient is -4.605×10 5 —-4.805×10 5 Between, X 8 The coefficient of the term is -7.172×10 11 —-7.372×10 11 Between, X 8 Y 2 The coefficient of the term is -3.290×10 11 —-3.490×10 11 Between, X4 Y 4 The coefficient is -1.043×10 11 —-1.243×10 11 Between, X 2 Y 6 The coefficient of the term is -3.351×10 8 —-3.551×10 8 Between, Y 8 The coefficient of the term is -4.654×10 14 —-4.854×10 14 In the XY polynomial of the fifth surface 31, X 2 The coefficient of the term is 3.083×10 2 -3.283×10 2 Between, Y 2 The coefficient of the term is 5.521×10 2 -5.721×10 2 Between, X 4 The coefficient of the term is -1.997×10 5 —-2.197×10 5 , Y 4 The coefficient of the term is -6.581×10 5 —-6.781×10 5 Between, X 2 Y 2 The coefficient of the term is -3.102×10 5 —-3.202×10 5 Between, X 6 The coefficient of the term is -5.835×10 8 —-6.035×10 8 Between, X 4 Y 2 The coefficient of the term is 8.732×10 8 -8.932×10 8 Between, X 2 Y 4 The coefficient of the term is -5.674×10 9 —-5.874×10 9 Between, Y 6 The coefficient of the term is -1.170×10 8 —-1.370×10 8 Between, X 8 The coefficient is -4.507×10 11 —-4.707×10 11 Between, X 8 Y 2 The coefficient of the term is -1.615×10 13 —-1.815×1013 Between, X 4 Y 4 The coefficient of the term is -3.376×10 12 —-3.576×10 12 Between, X 2 Y 6 The coefficient of the term is 1.257×10 10 -1.457×10 10 Between, Y 8 The coefficient of the term is -1.666×10 16 —-1.866×10 16 between.

[0015] Furthermore, the total system length L of the optical receiving device is 18-22 mm, the relative illumination of the optical receiving surface is greater than 0.95, the full field angle W is 70-72°, the focal length f is 6.5-7.5 mm, and the optical gain is between 11.5-13.5.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] (1) Based on the limitations of traditional visible light communication optical receiving antennas, the present invention designs a receiving device based on an XY polynomial free-form surface, which effectively increases the field of view of the optical structure by about 35° while maintaining high optical gain.

[0018] (2) The present invention optimizes the parameters of the XY polynomial free-form surface to obtain an optical receiving device with high optical gain, large field of view, good channel performance, a spot diameter of only 3 mm, and energy distribution uniformity greater than 95%.

[0019] (3) The optical receiving device based on the free-form surface designed by the present invention uses only three lenses, has a compact structure, is easy to install, and the lenses are all made of optical plastic materials, which greatly reduces the processing difficulty and saves processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of an optical receiving device based on a free-form surface according to the present invention.

[0021] Figure 2 Schematic diagram of the relative illumination of the receiving surface of the optical receiving device based on the free-form surface in Example 1 of the present invention.

[0022] Figure 3 Schematic diagram of the light spot of the receiving surface of the optical receiving device based on the free-form surface in Example 1 of the present invention; wherein, (a) is the two-dimensional light spot diagram of the receiving surface; (b) is the lateral received light illumination curve of the receiving surface; and (c) is the three-dimensional light spot diagram of the receiving surface.

[0023] Figure 4 Schematic diagram of the assembly model of the optical receiving device based on the free-form surface in Example 1 of the present invention.

[0024] Figure 5 Schematic diagram of relative illumination of a receiving surface of an optical receiving device based on a free-form surface in Embodiment 2 of the present invention.

[0025] Figure 6 Schematic diagram of the light spot of the receiving surface of the optical receiving device based on the free-form surface in Example 2 of the present invention; wherein, (a) is the two-dimensional light spot diagram of the receiving surface; (b) is the lateral received light illumination curve of the receiving surface; and (c) is the three-dimensional light spot diagram of the receiving surface.

[0026] Figure 7 It is a schematic diagram of an assembly model of an optical receiving device based on a free-form surface in Example 2 of the present invention.

[0027] Numbers in the figure: 1 is the first positive lens, 2 is the first negative lens, 3 is the second positive lens, 4 is the lens barrel, 5 is the lens spacer, 6 is the aperture spacer, 7 is the aperture, 8 is the infrared filter, 11 is the first surface, 12 is the second surface, 21 is the third surface, 22 is the fourth surface 22, 31 is the fifth surface, and 32 is the sixth surface 32. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0029] Example 1

[0030] like Figure 1 As shown, an optical receiving device based on a free-form surface includes: a first positive lens 1, a first negative lens 2, a second positive lens 3, a lens barrel 4, a lens spacer 5, an aperture spacer 6, an aperture 7, and an infrared filter 8. The first positive lens 1 includes a first surface 11 facing the object surface and a second surface 12 facing the receiving surface; the first negative lens 2 includes a third surface 21 facing the object surface and a fourth surface 22 facing the receiving surface; the second positive lens 3 includes a fifth surface 31 facing the object surface and a sixth surface 32 facing the receiving surface; the lens spacer 5 is mainly used to fix and separate the first positive lens 1 and the first negative lens 2; the aperture spacer 5 is mainly used to fix the aperture 7.

[0031] The focal length of the first positive lens 1 is 0.065 mm. -1 The first surface 11 is a convex spherical surface with a curvature radius of 10.966 mm; the second surface 12 is an XY polynomial free-form surface with a curvature radius of -27.790 mm; and the center thickness of the first positive lens 1 is 2.759 mm.

[0032] The focal length of the first negative lens 2 is 0.153 mm. -1 The third surface 21 is a concave spherical surface with a curvature radius of -6.702 mm; the fourth surface 22 is a concave spherical surface with a curvature radius of 6.415 mm; and the center thickness of the first negative lens 2 is 1.114 mm.

[0033] The focal length of the second positive lens 3 is 0.151 mm. -1 The fifth surface 31 is an XY polynomial free-form surface with a curvature radius of 16.106 mm; the sixth surface 32 is a convex spherical surface with a curvature radius of -4.101 mm; and the center thickness of the second positive lens 3 is 3.953 mm.

[0034] The distance between the center of the second surface 12 and the center of the third surface 21 is 0.765 mm; the distance between the center of the fourth surface 22 and the center of the aperture 7 is 2.152 mm; the distance between the center of the aperture 7 and the center of the fifth surface 31 is 1.473 mm.

[0035] The order of the XY polynomial self-surface is eight, and the equation is described as:

[0036]

[0037] in: c is the curvature and k is the conic section coefficient.

[0038] The conic coefficient of the second surface 12 is 1.167; the conic coefficient of the fifth surface 31 is -20.681; in the XY polynomial of the second surface 12, X 2 The coefficient of the term is -8.540×10 0 , Y 2 The term coefficient is -7.500×10 -1 , X 4 The term coefficient is -2.100×10 5 , Y 4 The term coefficient is 5.554×10 4 , X 2 Y 2 The term coefficient is -5.040×10 2 , X 6 The term coefficient is -1.328×10 8 , X 4 Y 2 The term coefficient is -1.186×10 8 , X 2 Y 4 The term coefficient is 8.082×10 7 , Y 6The term coefficient is -4.705×10 5 , X 8 The coefficient of the term is -7.272×10 11 , X 8 Y 2 The coefficient of the term is -3.390×10 11 , X 4 Y 4 The term coefficient is -1.143×10 11 , X 2 Y 6 The coefficient of the term is -3.451×10 8 , Y 8 The term coefficient is -4.754×10 14 In the XY polynomial of the fifth surface 31, X 2 The term coefficient is 3.183×10 2 , Y 2 The term coefficient is 5.621×10 2 , X 4 The term coefficient is -2.097×10 5 , Y 4 The coefficient of the term is -6.681×10 5 , X 2 Y 2 The coefficient of the term is -3.102×10 5 , X 6 The coefficient of the term is -5.935×10 8 , X 4 Y 2 The coefficient of the term is 8.832×10 8 , X 2 Y 4 The coefficient of the term is -5.774×10 9 , Y 6 The term coefficient is -1.270×10 8 , X 8 The term coefficient is -4.607×10 11 , X 8 Y 2 The term coefficient is -1.715×10 13 , X 4 Y 4 The coefficient of the term is -3.476×10 12 , X 2 Y 6 The term coefficient is 1.357×10 10 , Y 8 The term coefficient is -1.766×10 16 .

[0039] like Figure 2As shown, within the 70.4° field of view of the optical receiving device in Example 1, the relative illumination of the optical receiving surface is greater than 0.95.

[0040] like Figure 3 As shown, Example 1 uses the optical receiving device based on the free-form surface to collect light information, and the resulting optical receiving surface light spot size is only 3 mm, and the light spot energy distribution is uniform.

[0041] like Figure 4 The figure shows the assembly model diagram of the optical receiving device in Example 1. The total length L of the system is 19.020 mm, the focal length f is 6.9 mm, the optical gain is 11.69, the optical receiving power is 0.5617 dBm, and the signal-to-noise ratio is 84.7054 dB.

[0042] The first positive lens 1 can be made of COC material, and the negative lens 2 and the second positive lens 3 can be made of PMMA material. The optical receiving device uses only three lenses, has a compact structure, is easy to install, and the lenses are all made of optical plastic material, which greatly reduces the processing difficulty and saves processing costs, and can be widely used in the field of visible light communication.

[0043] Example 2

[0044] like Figure 1 As shown, an optical receiving device based on a free-form surface includes: a first positive lens 1, a first negative lens 2, a second positive lens 3, a lens barrel 4, a lens spacer 5, an aperture spacer 6, an aperture 7, and an infrared filter 8. The first positive lens 1 includes a first surface 11 facing the object surface and a second surface 12 facing the receiving surface; the first negative lens 2 includes a third surface 21 facing the object surface and a fourth surface 22 facing the receiving surface; the second positive lens 3 includes a fifth surface 31 facing the object surface and a sixth surface 32 facing the receiving surface; the lens spacer 5 is mainly used to fix and separate the first positive lens 1 and the first negative lens 2; the aperture spacer 5 is mainly used to fix the aperture 7.

[0045] The focal length of the first positive lens 1 is 0.068 mm. -1 The first surface 11 is a convex spherical surface with a curvature radius of 11.058 mm; the second surface 12 is an XY polynomial free-form surface with a curvature radius of -27.770 mm; and the center thickness of the first positive lens 1 is 2.769 mm.

[0046] The focal length of the first negative lens 2 is -0.163 mm -1 The third surface 21 is a concave spherical surface with a curvature radius of -6.802 mm; the fourth surface 22 is a concave spherical surface with a curvature radius of 6.486 mm; and the center thickness of the first negative lens 2 is 1.164 mm.

[0047] The focal length of the second positive lens 3 is 0.158 mm -1 The fifth surface 31 is an XY polynomial free-form surface with a curvature radius of 16.186 mm; the sixth surface 32 is a convex spherical surface with a curvature radius of -4.188 mm; and the center thickness of the second positive lens 3 is 4.053 mm.

[0048] The distance between the center of the second surface 12 and the center of the third surface 21 is 0.865 mm; the distance between the center of the fourth surface 22 and the center of the aperture 7 is 2.252 mm; and the distance between the center of the aperture 7 and the center of the fifth surface 31 is 1.573 mm.

[0049] The order of the XY polynomial self-surface is eight, and the equation is described as:

[0050]

[0051] in: c is the curvature and k is the conic section coefficient.

[0052] The conic coefficient of the second surface 12 is 1.267; the conic coefficient of the fifth surface 31 is -20.692; in the XY polynomial of the second surface 12, X 2 The term coefficient is -8.560×10 0 , Y 2 The term coefficient is -7.590×10 -1 , X 4 The term coefficient is -2.156×10 5 , Y 4 The coefficient of the term is 5.584×10 4 , X 2 Y 2 The coefficient of the term is -5.140×10 2 , X 6 The term coefficient is -1.428×10 8 , X 4 Y 2 The term coefficient is -1.286×10 8 , X 2 Y 4 The term coefficient is 7.982×10 7 , Y 6 The term coefficient is -4.605×10 5 , X 8 The coefficient of the term is -7.172×10 11 , X 8 Y 2 The coefficient of the term is -3.490×10 11 , X 4Y 4 The term coefficient is -1.243×10 11 , X 2 Y 6 The coefficient of the term is -3.551×10 8 , Y 8 The coefficient of the term is -4.654×10 14 In the XY polynomial of the fifth surface 31, X 2 The term coefficient is 3.083×10 2 , Y 2 The term coefficient is 5.521×10 2 , X 4 The term coefficient is -2.197×10 5 , Y 4 The term coefficient is 6.781×10 5 , X 2 Y 2 The coefficient of the term is -3.202×10 5 , X 6 The coefficient of the term is -5.835×10 8 , X 4 Y 2 The coefficient of the term is 8.732×10 8 , X 2 Y 4 The coefficient of the term is -5.874×10 9 , Y 6 The term coefficient is -1.370×10 8 , X 8 The term coefficient is -4.507×10 11 , X 8 Y 2 The term coefficient is -1.615×10 13 , X 4 Y 4 The coefficient of the term is -3.376×10 12 , X 2 Y 6 The term coefficient is 1.457×10 10 , Y 8 The term coefficient is -1.866×10 16 .

[0053] like Figure 5 As shown, within the 70.4° field of view of the optical receiving device in Example 2, the relative illumination of the optical receiving surface is greater than 0.93.

[0054] like Figure 6 As shown, the optical receiving device based on the free-form surface described in Example 2 is used to collect light information, and the resulting optical receiving surface light spot size is only 3 mm, and the light spot energy distribution is uniform.

[0055] like Figure 7 The figure shows the assembly model diagram of the optical receiving device in Example 2. The total length L of the system is 22 mm, the focal length f is 7.5 mm, the optical gain is 12.58, the optical receiving power is 0.5822 dBm, and the signal-to-noise ratio is 83.8416 dB.

[0056] The first positive lens 1 can be made of COC material, and the negative lens 2 and the second positive lens 3 can be made of PMMA material. The optical receiving device uses only three lenses, has a compact structure, is easy to install, and the lenses are all made of optical plastic material, which greatly reduces the processing difficulty and saves processing costs, and can be widely used in the field of visible light communication.

[0057] The implementation methods of the present invention are not limited to the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An optical receiving device based on a free-form surface, characterized in that: The lens comprises a first positive lens (1), a first negative lens (2), a second positive lens (3), a lens barrel (4), an aperture (7), and an infrared filter (8); the first positive lens (1), the negative lens (2), the aperture (7), the second positive lens (3), and the infrared filter are coaxially fixed to the inner wall of the lens barrel (4) in sequence; the first positive lens (1) and the negative lens (2) are separated by a lens spacer (5), and the aperture (7) is fixed to the inner wall of the lens barrel (4) through an aperture spacer (6); the first positive lens (1) comprises a first surface (11) facing the object surface and a second surface (12) facing the receiving surface; the negative lens (2) comprises a third surface (21) facing the object surface and a fourth surface (22) facing the receiving surface; the second positive lens (3) comprises a fifth surface (31) facing the object surface and a sixth surface (32) facing the receiving surface; The focal length of the first positive lens (1) is between 0.060 and 0.070 mm. -1 The first surface (11) is a convex spherical surface with a radius of curvature between 10.866 mm and 11.066 mm; the second surface (12) is an XY polynomial free-form surface with a radius of curvature between -27.690 mm and -27.890 mm; the center thickness of the first positive lens (1) is between 2.659 mm and 2.859 mm; The invention is characterized in that the focal length of the negative lens (2) is between -0.143 and -0.163 mm. -1 The third surface (21) is a concave spherical surface with a curvature radius between -6.602 and -6.802 mm; the fourth surface (22) is a concave spherical surface with a curvature radius between 6.315 and 6.515 mm; the center thickness of the first negative lens (2) is between 1.014 and 1.214 mm; The focal length of the second positive lens (3) is between 0.141 and 0.161 mm. -1 The fifth surface (31) is an XY polynomial free-form surface with a radius of curvature between 16.006 and 16.206 mm; the sixth surface (32) is a convex spherical surface with a radius of curvature between -4.001 and -4.201 mm; the center thickness of the second positive lens (3) is between 3.853 and 4.053 mm; The order of the XY polynomial self-surface is eight, and the equation is described as: in: c is the curvature, k is the conic section coefficient, and the subscript E is the polynomial coefficient.

2. The optical receiving device based on a free-form surface according to claim 1, characterized in that: The conic curve coefficient of the second surface (12) is between 1.067 and 1.267; the conic curve coefficient of the fifth surface (31) is between -20.581 and -20.781; in the XY polynomial of the second surface (12), X 2 The coefficient of the term is -8.440×10 0 —-8.640×10 0 Between, Y 2 The coefficient of the term is -7.400×10 -1 —-7.600×10 -1 Between, X 4 The coefficient of the term is -2.000×10 5 —-2.200×10 5 , Y 4 The coefficient of the term is 5.454×10 4 -5.654×10 4 Between, X 2 Y 2 The coefficient of the term is -4.940×10 2 —-5.140×10 2 Between, X 6 The coefficient of the term is -1.228×10 8 —-1.428×10 8 Between, X 4 Y 2 The coefficient of the term is -1.086×10 8 —-1.286×10 8 Between, X 2 Y 4 The coefficient of the term is 7.982×10 7 -8.182×10 7 Between, Y 6 The coefficient of the term is -4.605×10 5 —-4.805×10 5 Between, X 8 The coefficient of the term is -7.172×10 11 —-7.372×10 11 Between, X 8 Y 2 The coefficient of the term is -3.290×10 11 —-3.490×10 11 Between, X 4 Y 4 The coefficient is -1.043×10 11 —-1.243×10 11 Between, X 2 Y 6 The coefficient of the term is -3.351×10 8 —-3.551×10 8 Between, Y 8 The coefficient of the term is -4.654×10 14 —-4.654×10 14 In the XY polynomial of the fifth surface (31), X 2 The coefficient of the term is 3.083×10 2 -3.283×10 2 Between, Y 2 The coefficient of the term is 5.521×10 2 -5.721×10 2 Between, X 4 The coefficient of the term is -1.997×10 5 —-2.197×10 5 , Y 4 The coefficient of the term is -6.581×10 5 —-6.781×10 5 Between, X 2 Y 2 The coefficient of the term is -3.102×10 5 —-3.202×10 5 Between, X 6 The coefficient of the term is -5.835×10 8 —-6.035×10 8 Between, X 4 Y 2 The coefficient of the term is 8.732×10 8 -8.932×10 8 Between, X 2 Y 4 The coefficient of the term is -5.674×10 9 —-5.874×10 9 Between, Y 6 The coefficient of the term is -1.170×10 8 —-1.370×10 8 Between, X 8 The coefficient is -4.507×10 11 —-4.707×10 11 Between, X 8 Y 2 The coefficient of the term is -1.615×10 13 —-1.815×10 13 Between, X 4 Y 4 The coefficient of the term is -3.376×10 12 —-3.576×10 12 Between, X 2 Y 6 The coefficient of the term is 1.257×10 10 -1.457×10 10 Between, Y 8 The coefficient of the term is -1.666×10 16 —-1.866×10 16 between.

3. The optical receiving device based on a free-form surface according to claim 2, characterized in that: The total system length L of the optical receiving device is 18-22 mm, the relative illumination of the optical receiving surface is greater than 0.95, the full field angle W is 70-72°, the focal length f is 6.5-7.5 mm, and the optical gain is between 11.5-13.5.

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