Underwater laser polarization imaging lens

Abstract

The application relates to an underwater laser polarization imaging lens and relates to the field of optical equipment, which comprises a curved window, a linear polaroid, a wave plate, a double Gauss optical assembly and a detector distributed along the light incidence direction, the curved window is a concave-convex lens with the convex surface facing the outside of the lens, the linear polaroid is a flat plate lens arranged obliquely, the wave plate is a 1 / 4 wave plate, and the double Gauss optical assembly is composed of six groups of lenses distributed at intervals to converge the circularly polarized light converted by the wave plate to the detector, and the application has the advantages that the problems of poor underwater imaging effect and short imaging distance of common imaging lenses are solved.

Description

Technical Field

[0001] This invention relates to the field of optical equipment technology, and in particular to an underwater laser polarization imaging lens. Background Technology

[0002] Underwater environments are characterized by their vast range, complex conditions, and high degree of concealment, making effective monitoring extremely challenging. Currently, underwater detection technologies are mainly divided into acoustic and optical detection. Acoustic detection suffers from difficulties in target identification, relatively poor real-time performance, and is highly susceptible to noise interference. Optical detection offers advantages such as intuitive imaging, clear details, and good real-time performance; however, light is severely affected by absorption and scattering during underwater propagation, significantly limiting the distance for underwater optical imaging and causing image quality degradation issues such as reduced brightness, decreased contrast, image blurring, and reduced resolution.

[0003] Therefore, to address the above shortcomings, it is necessary to provide an underwater laser polarization imaging lens. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The technical problem to be solved by the present invention is that ordinary optical imaging technology is usually difficult to obtain ideal imaging results in underwater environments.

[0006] (II) Technical Solution

[0007] To address the aforementioned technical problems, this invention provides an underwater laser polarization imaging lens, comprising a curved window, a linear polarizer, a waveplate, a double Gaussian optical assembly, and a detector, all distributed along the incident direction of the light. The curved window is a concave-convex lens with the convex surface facing outwards from the lens. The linear polarizer is an inclined flat plate lens, the waveplate is a quarter-waveplate, and the double Gaussian optical assembly consists of six sets of spaced lenses to converge the circularly polarized light converted by the waveplate onto the detector.

[0008] As a further explanation of the present invention, preferably, the dual high-speed optical assembly includes a first positive lens, a second positive lens, a first negative lens, an aperture stop, a second negative lens, a third positive lens, and a fourth positive lens distributed along the incident light direction. The first positive lens has a convex surface on the side near the incident light; the second positive lens has a convex surface on the side near the incident light and a concave surface in the middle of the side near the outgoing light; the first negative lens has a convex surface on the side near the incident light and a concave surface in the middle of the side near the outgoing light; both sides of the second negative lens have concave surfaces in the middle; both sides of the third positive lens have convex surfaces; and the fourth positive lens has a convex surface on the side near the incident light.

[0009] As a further explanation of the invention, preferably, the laser is incident perpendicularly from the curved window to reduce dispersion.

[0010] As a further explanation of the present invention, preferably, the lens adopts a heatless design.

[0011] (III) Beneficial Effects

[0012] The above-described technical solution of the present invention has the following advantages:

[0013] This invention, through its calorimetric design, ensures imaging quality over a wide temperature range by matching the expansion coefficients of the lens and the supporting structure. At the same time, it reduces beam dispersion, enabling better convergence of beams in different spectral bands. It is applicable to laser imaging of various wavelengths and provides excellent imaging quality. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the lens assembly of the present invention.

[0015] In the figure: 1. Curved window; 2. Linear polarizer; 3. Waveplate; 4. Double Gaussian optical assembly; 41. First positive lens; 42. Second positive lens; 43. First negative lens; 44. Aperture; 45. Second negative lens; 46. Third positive lens; 47. Fourth positive lens; 5. Detector. Detailed Implementation

[0016] 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 embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] An underwater laser polarization imaging lens, such as Figure 1 As shown, it includes a curved window 1, a linear polarizer 2, a waveplate 3, a double Gaussian optical assembly 4, and a detector 5, all distributed along the incident direction of light. The curved window 1 is a concave-convex lens with the convex surface facing outwards. The linear polarizer 2 is a flat plate lens arranged at an angle. The waveplate 3 is a quarter-wave plate. The double Gaussian optical assembly 4 consists of six sets of spaced lenses to converge the circularly polarized light converted by the waveplate 3 onto the detector 5.

[0018] like Figure 1 As shown, the curved window 1 is the head lens of the lens. Light rays incident on its front surface and light rays exiting from its rear surface are nearly perpendicular to the tangent direction at the location of the light ray. Light rays of different wavelengths can maintain basically perpendicular incident and exit perpendicularly from the rear surface. By using the curved window 1, beam dispersion can be reduced. Less dispersion allows beams of different spectral bands to converge better, making it suitable for laser imaging of multiple wavelengths.

[0019] like Figure 1 As shown, the linear polarizer 2 is a polarizing device placed at a Brewster angle to the optical axis (horizontal direction), which can convert the incident laser echo into linearly polarized light with its polarization direction in the vertical direction. The waveplate 3 is placed at a 45° angle to the vertical direction to convert the linearly polarized light into circularly polarized light.

[0020] like Figure 1 As shown, the dual high-speed optical assembly 4 includes a first positive lens 41, a second positive lens 42, a first negative lens 43, an aperture 44, a second negative lens 45, a third positive lens 46, and a fourth positive lens 47 distributed along the incident light direction. The first positive lens 41 has a convex surface near the incident light; the second positive lens 42 has a convex surface near the incident light and a concave surface in the middle of the side near the outgoing light; the first negative lens 43 has a convex surface near the incident light and a concave surface in the middle of the side near the outgoing light; the second negative lens 45 has concave surfaces in the middle of both sides; the third positive lens 46 has convex surfaces on both sides; and the fourth positive lens 47 has a convex surface near the incident light.

[0021] By optimizing the dual high-speed optical assembly 4 composed of six lenses, using lens material, radius of curvature, lens thickness, and air gap as optimization variables, vertical aberration can be corrected. At the same time, by reasonably arranging the spacing of the lenses, a larger number of turns with an F number of 2 can be achieved under a certain field of view, resulting in more light intake and improved detection distance.

[0022] like Figure 1 As shown, the distance between the rear end face of the lens in contact with detector 5 and detector 5 is 17.526 mm, allowing light passing through the dual high-speed optical components 4 to converge onto the surface of detector 5 for imaging. Combined with the thermal-free design of the lenses, the lens can operate in the 486mm–656mm wavelength band and maintain a relatively stable back focus within a temperature range of -20℃ to +60℃. Polarization imaging lenses utilize polarization characteristics to solve the problems of low signal-to-noise ratio and short effective range in underwater imaging with ordinary lenses, effectively improving target recognition capabilities, increasing detection range, and expanding the underwater imaging monitoring range, thus possessing significant technical application value.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An underwater laser polarization imaging lens, characterized in that: The system includes a curved window (1) distributed along the incident direction of light, a linear polarizer (2), a waveplate (3), a double Gaussian optical assembly (4), and a detector (5). The curved window (1) is a concave-convex lens with the convex surface facing outwards. The linear polarizer (2) is a tilted flat lens. The waveplate (3) is a quarter-wave plate. The double Gaussian optical assembly (4) includes a first positive lens (41), a second positive lens (42), a first negative lens (43), an aperture (44), a second negative lens (45), a third positive lens (46), and a fourth positive lens (47) distributed along the incident direction of light. The positive lens (41) has a convex surface on the side near the incident light; the second positive lens (42) has a convex surface on the side near the incident light, and the middle part of the second positive lens (42) near the outgoing light is concave; the first negative lens (43) has a convex surface on the side near the incident light, and the middle part of the first negative lens (43) near the outgoing light is concave; the middle parts of both sides of the second negative lens (45) are concave; the third positive lens (46) has convex surfaces on both sides; the fourth positive lens (47) has a convex surface on the side near the incident light. The six sets of lenses are spaced apart to converge the circularly polarized light converted by the waveplate (3) to the detector (5).

2. The underwater laser polarization imaging lens according to claim 1, characterized in that: The laser is incident perpendicularly from the curved window (1) to reduce dispersion.

3. The underwater laser polarization imaging lens according to claim 2, characterized in that: The lens employs a heat-free design.

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