A compact optical system for a parallel light pipe

Abstract

The application discloses a compact collimator optical system, and belongs to the field of optics; the optical system is sequentially provided with a primary mirror, a secondary mirror, a plane mirror, a target plate and a light source along an optical axis; the primary mirror and the secondary mirror are both quadric surfaces, the primary mirror is a concave surface, and the secondary mirror is a convex surface; the focal length of the optical system is 1500mm-3000mm, the aperture is 200mm-400mm, and the field of view is 0.2-0.5 degrees. The light path is folded multiple times through the secondary mirror and the plane mirror, the compact collimator optical system is designed, the optical system has few optical elements, the structure is compact, the volume and the weight of the optical system are effectively reduced, and the optical system can be applied to a 0.4-14 mu m full-waveband portable collimator optical system.

Description

Technical Field

[0001] This invention belongs to the field of optics, specifically relating to a compact collimator optical system. Background Technology

[0002] Currently, collimators used in outdoor environments generally suffer from the disadvantages of being large in size and heavy in weight, making them inconvenient to carry and transport.

[0003] Existing technologies disclose aperture expansion devices for optical axis detection systems of multispectral handheld observers, used to expand the usable aperture of small-diameter collimators. However, these devices, consisting of double pentaprisms and guide rails, can only maintain the beam direction in the meridional direction; the beam direction in the sagittal direction requires precise adjustment of the pentaprism's orientation and the use of high-precision guide rails and sliders. Existing portable broadband multi-axis collimation calibration devices use off-axis parabolic collimator optical systems. Although a single planar folding mirror is used to fold the light path, the overall optical path volume remains large.

[0004] Therefore, this invention designs a compact collimator optical system with fewer optical components, a compact structure, small size, and light weight. Summary of the Invention

[0005] The technical problem to be solved:

[0006] To overcome the shortcomings of existing technologies, this invention provides a compact collimator optical system. By using secondary mirrors and plane mirrors to fold the light path multiple times, a compact collimator optical system design is achieved. The optical system has fewer optical components and a compact structure, effectively reducing the size and weight of the optical system. It can be applied to portable collimator optical systems covering the entire 0.4μm to 14μm wavelength range.

[0007] The technical solution of the present invention is: a compact collimator optical system, wherein a primary mirror, a secondary mirror, a plane mirror, a target plate and a light source are arranged sequentially along the optical axis; both the primary mirror and the secondary mirror are quadratic surfaces, the primary mirror being concave and the secondary mirror being convex; the focal length of the optical system is 1500mm to 3000mm, the aperture is 200mm to 400mm, and the field of view is 0.2° to 0.5°.

[0008] A further technical solution of the present invention is: the main mirror has a central through hole for placing a plane mirror; the back of the plane mirror does not protrude from the back of the main mirror.

[0009] A further technical solution of the present invention is: the secondary mirror has a central through hole, the outer diameter of which does not exceed 1 / 3 of the diameter of the primary mirror, and the inner diameter of the central through hole does not exceed 1 / 3 of the outer diameter of the secondary mirror.

[0010] A further technical solution of the present invention is that the focal plane of the target plate and the optical system coincide, and the target plate is a replaceable structure; the length of the target plate to the back of the primary mirror does not exceed 1 / 5 of the focal length of the collimator optical system.

[0011] A further technical solution of the present invention is that the light source is a broadband composite light source with a working wavelength of 0.4μm to 14μm.

[0012] A further technical solution of the present invention is that the primary mirror, the secondary mirror and the plane mirror are all made of low-expansion glass, and their reflective surfaces are coated with a wide-band metallic reflective film.

[0013] A further technical solution of the present invention is as follows: the specific parameters of each optical element of the optical system are as follows:

[0014] 1 Main mirror -629.44 -214.3 20 quartz quadric surface 2 secondary mirror -254.168 224.3 10 quartz quadric surface 3 plane mirror ∞ 264.3 10 quartz flat 4 target plate ∞ - - quartz flat

[0015] A further technical solution of the present invention is that the quadratic surface coefficients of the primary mirror and the secondary mirror are -1.04 and -2.5984, respectively.

[0016] A further technical solution of the present invention is that the elevation of the quadratic surface satisfies the following expression:

[0017]

[0018] Where z is the sag at height h, R is the vertex radius of curvature, and k is the conic section constant.

[0019] A further technical solution of the present invention is that the structural material of the optical system is carbon fiber or indium steel, which has a thermal expansion coefficient close to that of the reflector, thus expanding its adaptability to temperature environments.

[0020] Beneficial effects

[0021] The beneficial effects of this invention are as follows: The compact collimator optical system proposed in this invention adopts a total reflection optical system design, which achieves a compact design with a wide wavelength range of 0.4μm to 14μm. It can be applied to the optical system of portable collimators, reducing the system size and weight, and has broad application prospects.

[0022] Figure 2 Simulation analysis shows that the MTF (Mean Transmission Factor) of each field of view is close to the diffraction limit. The MTF curve of the specific embodiment of the compact collimator optical system is close to the diffraction limit, ensuring good imaging quality and meeting the requirements for collimator use. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the optical path of a specific embodiment of the compact collimator optical system described in this invention.

[0024] Figure 2 The MTF curve is shown in a specific embodiment of the present invention.

[0025] Explanation of reference numerals in the attached diagram: 1. Primary mirror, 2. Secondary mirror, 3. Plane mirror, 4. Target plate, 5. Light source. Detailed Implementation

[0026] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0027] Existing collimators used in outdoor environments generally suffer from large size and heavy weight, causing inconvenience in carrying and transporting them. This invention provides a compact collimator optical system, in which a primary mirror 1, a secondary mirror 2, a plane mirror 3, a target plate 4, and a light source 5 are arranged sequentially along the optical axis of the incident direction. Both the primary mirror 1 and the secondary mirror 2 are quadratic surfaces, with the primary mirror 1 being concave and the secondary mirror 2 being convex. The primary mirror 1, the secondary mirror 2, and the plane mirror 3 are all made of low-expansion glass, such as quartz or microcrystalline glass.

[0028] Specifically, the light rays at the center of the primary mirror 1 of the optical system are blocked by the secondary mirror, and the blocking diameter does not exceed 1 / 3 of the diameter of the primary mirror (1). A circular hole is machined in the blocking area at the center of the primary mirror 1.

[0029] Specifically, the plane mirror 3 of the optical system is located inside the central circular hole of the main mirror 1, and the back of the plane mirror 3 does not protrude from the back of the main mirror 2.

[0030] Specifically, a circular hole is machined at the center of the secondary mirror 2 of the optical system so that light can pass through directly, and the diameter of the circular hole does not exceed 1 / 3 of the diameter of the secondary mirror 2.

[0031] Specifically, the target plate 4 of the optical system coincides with the focal plane of the optical system. The target plate 4 is a portable and replaceable target plate that can be replaced according to usage requirements.

[0032] Specifically, the light source 5 of the optical system is a broadband composite light source with an operating wavelength of 0.4μm to 14μm.

[0033] Specifically, the optical system has a focal length of 1500mm to 3000mm, an aperture of 200mm to 400mm, and a field of view of 0.2° to 0.5°.

[0034] Specifically, the length from the target plate 4 to the back of the primary mirror 1 in the optical system does not exceed 1 / 5 of the focal length of the collimator optical system.

[0035] Specifically, the reflective surfaces of the primary mirror 1, secondary mirror 2, and plane mirror 3 of the optical system are all coated with a wide-band metallic reflective film, such as an aluminum film, a silver film, or a gold film.

[0036] Specifically, the optical system is constructed using carbon fiber or indium steel, which have a thermal expansion coefficient close to that of the mirror, thus expanding its adaptability to temperature environments.

[0037] The above technical solution will be further explained below with reference to the accompanying drawings and specific examples.

[0038] The main design specifications of a compact collimator optical system are shown in the table below.

[0039] Table 1 Design Specifications for Wideband Catalytic Reflective Imaging Optical Systems

[0040] Operating band 0.4μm~14μm caliber 200mm focal length 1500mm Field of view 0.4° Total length from target plate to the back of primary mirror ≤300mm

[0041] Reference Figure 1 As shown in the diagram, this embodiment presents an optical path diagram of a compact collimator optical system. Along the optical axis of the incident direction, a primary mirror 1, a secondary mirror 2, a plane mirror 3, a target plate 4, and a light source 5 are arranged sequentially. The optical system operates in the wavelength range of 0.4 μm to 14 μm, has an entrance pupil diameter of 200 mm, a focal length of 1500 mm, a field of view of 0.4°, and a total length from the target plate to the back of the primary mirror of only 264.3 mm. Specific parameters of each optical component of the optical system are shown in Table 2.

[0042] Table 2 Optical System Parameters for Optical Path 1

[0043] 1 Main mirror -629.44 -214.3 20 quartz quadric surface 2 secondary mirror -254.168 224.3 10 quartz quadric surface 3 plane mirror ∞ 264.3 10 quartz flat 4 target plate ∞ - - quartz flat

[0044] Table 3. Coefficients of Quadruple Surfaces

[0045] Main mirror -1.04 secondary mirror -2.5984

[0046] The sagitta of the above quadratic surface satisfies the following expression:

[0047]

[0048] Where z is the sag at height h, R is the vertex radius of curvature, and k is the conic section constant.

[0049] Reference Figure 2 The simulation analysis shown indicates that the MTF curve of the specific embodiment of the compact collimator optical system is close to the diffraction limit, which can ensure good imaging quality of the optical system and meet the requirements for the use of collimators.

[0050] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A compact collimator optical system, characterized in that: The optical system is arranged in sequence along the optical axis, consisting of a primary mirror, a secondary mirror, a plane mirror, a target plate, and a light source; both the primary mirror and the secondary mirror are quadratic surfaces, with the primary mirror being concave and the secondary mirror being convex; the focal length of the optical system is 1500mm to 3000mm, the aperture is 200mm to 400mm, and the field of view is 0.2° to 0.5°. The primary mirror has a central through hole for placing a plane mirror; the back of the plane mirror does not protrude from the back of the primary mirror. The secondary mirror has a central through hole, the outer diameter of which does not exceed 1 / 3 of the diameter of the primary mirror, and the inner diameter of the central through hole does not exceed 1 / 3 of the outer diameter of the secondary mirror. The specific parameters of each optical element in the optical system are as follows:

2. The compact collimator optical system according to claim 1, characterized in that: The target plate and the focal plane of the optical system coincide, and the target plate is a replaceable structure. The length of the target plate from the back of the primary mirror does not exceed 1 / 5 of the focal length of the collimator optical system.

3. The compact collimator optical system according to claim 2, characterized in that: The light source is a broadband composite light source with an operating wavelength of 0.4μm to 14μm.

4. The compact collimator optical system according to claim 3, characterized in that: The primary mirror, secondary mirror, and plane mirror are all made of low-expansion glass, and their reflective surfaces are coated with a wide-band metallic reflective film.

5. The compact collimator optical system according to claim 4, characterized in that: The quadratic surface coefficients of the primary mirror and the secondary mirror are -1.04 and -2.5984, respectively.

6. The compact collimator optical system according to claim 5, characterized in that: The quadratic surface elevation satisfies the following expression: Where z is the sag at height h, R is the vertex radius of curvature, and k is the conic section constant.

7. A compact collimator optical system according to any one of claims 1-6, characterized in that: The optical system is constructed using carbon fiber or indium steel, which have a coefficient of thermal expansion similar to that of the mirror, thus expanding its adaptability to different temperature environments.

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