Compact panoramic ring optical system

Abstract

The compact panoramic annular optical system relates to the technical field of optical systems, and solves the problem of poor compactness of the existing structure. The system includes a panoramic head unit, an aperture diaphragm, a relay lens group and an image sensor arranged in sequence along the optical axis, the panoramic head unit is located on the left side of the aperture diaphragm, the panoramic head unit includes a rotationally symmetrical first Q-con aspheric surface and a rotationally symmetrical second Q-con aspheric surface, the first Q-con aspheric surface and the second Q-con aspheric surface have the same surface shape and are both convex to the left, the first Q-con aspheric surface is located on the left side of the panoramic head unit, including a circular reflection surface and an annular transmission surface, the circular reflection surface is located in the ring of the annular transmission surface, the second Q-con aspheric surface is located on the right side of the panoramic head unit, including a circular transmission surface and an annular reflection surface, and the circular transmission surface is located in the ring of the annular reflection surface. The present invention has a wide field of view, small distortion, easy processing and manufacturing, and a simpler and more compact structure.

Description

Technical Field

[0001] The invention relates to the technical field of optical systems, and in particular to a compact panoramic annular optical system. Background Art

[0002] The lens panoramic annular optical system is a catadioptric panoramic system, generally composed of a panoramic head unit and a relay lens group. The panoramic annular optical system uses a plane cylindrical projection method to image objects within a 360° range around the optical axis of the system and within a certain angle of the vertical field of view into a two-dimensional circular area through its special system. Due to the compact structure, wide field of view, and small distortion of the panoramic annular optical system, it is widely used in various fields.

[0003] With the development of panoramic annular optical systems, there are higher requirements for the simplification and compactness of the system structure. Taking into account the single surface shape of the traditional head unit, which will lead to the increase in the size of the head unit and the lack of compactness of the optical system, most methods currently add a glued surface to the panoramic head unit or add an aspheric surface to the relay system, which increases the complexity of the system, increases the size of the system, and is not easy to make the system compact. Summary of the invention

[0004] In order to solve the problem that the existing compact panoramic annular optical system has poor compactness and needs to be improved urgently, the present invention provides a compact panoramic annular optical system.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0006] A compact panoramic annular optical system comprises a panoramic head unit, an aperture stop, a relay lens group and an image sensor arranged in sequence along an optical axis, wherein the panoramic head unit is located on the left side of the aperture stop, and the panoramic head unit comprises a rotationally symmetrical first Q-con aspheric surface and a rotationally symmetrical second Q-con aspheric surface, the first Q-con aspheric surface and the second Q-con aspheric surface have the same surface shape and are both convex to the left, the first Qcon aspheric surface is located on the left side surface of the panoramic head unit, and comprises a circular reflection surface and an annular transmission surface, the circular reflection surface is located in the ring of the annular transmission surface, the second Q-con aspheric surface is located on the right side surface of the panoramic head unit, and comprises a circular transmission surface and an annular reflection surface, the circular transmission surface is located in the ring of the annular reflection surface;

[0007] The incident light beam enters the panoramic head unit through the annular transmission surface, is reflected by the annular reflection surface in turn, is reflected by the circular reflection surface, and then is emitted from the panoramic head unit through the circular transmission surface. The light beam emitted from the circular transmission surface is limited by the aperture stop in turn, converged by the relay lens group and corrected for aberration, and then imaged on the image sensor.

[0008] The beneficial effects of the present invention are:

[0009] The compact panoramic annular optical system of the present invention creatively introduces two rotationally symmetrical Q-con aspheric surfaces into the panoramic head unit through the design of the panoramic head unit. The compactness is improved by appropriately reducing the thickness and aperture of the Q-con aspheric surfaces when the system permits, thereby achieving the overall compactness of the panoramic annular optical system. The processing difficulty is reduced by making the first Q-con aspheric surface and the second Q-con aspheric surface have the same surface shape. The compact panoramic annular optical system of the present invention has the advantages of wide field of view, small distortion, easy processing and manufacturing, and further compactness. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic structural diagram of the compact panoramic annular optical system of the present invention.

[0011] Figure 2 It is a structural diagram of a panoramic head unit of the compact panoramic annular optical system of the present invention.

[0012] Figure 3 This is the MTF diagram of the complex light diffraction of the compact panoramic annular optical system of the present invention.

[0013] Figure 4 It is a point diagram of the compact panoramic annular optical system of the present invention.

[0014] In the figure: 1. annular transmission surface, 2. annular reflection surface, 3. circular reflection surface, 4. circular transmission surface, 5. first annular light absorption surface, 6. second annular light absorption surface, 7. third annular light absorption surface, 8. aperture stop, 9. first double glued lens, 10. second double glued lens, 11. field lens, 12. image sensor, 13. panoramic head unit, 14. relay lens group. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0016] Compact panoramic ring optical system, such as Figure 1 , including a panoramic head unit 13, an aperture stop 8, a relay lens group 14 and an image sensor 12 arranged in sequence along the optical axis. Specifically, the panoramic head unit 13, the aperture stop 8, the relay lens group 14 and the image sensor 12 are arranged in sequence from left to right, and left and right are only described as two different directions. Figure 2The panoramic head unit 13 includes a first Q-con aspheric surface and a second Q-con aspheric surface, and both the first Q-con aspheric surface and the second Q-con aspheric surface are rotationally symmetric surfaces. The surface shapes of the first Q-con aspheric surface and the second Q-con aspheric surface are the same, and all parameters for determining the surface shapes are the same. The first Q-con aspheric surface is located on the left side surface of the panoramic head unit 13, and the first Q-con aspheric surface bulges to the left. The first Q-con aspheric surface includes a circular reflection surface 3 and an annular transmission surface 1. The circular reflection surface 3 is located in the ring of the annular transmission surface 1, and the distance between the inner edge of the annular transmission surface 1 and the optical axis is greater than or equal to the distance between the outer edge of the circular reflection surface 3 and the optical axis. The second Q-con aspheric surface is located on the right side surface of the panoramic head unit 13, and the second Q-con aspheric surface bulges to the left. The second Q-con aspheric surface includes a circular transmission surface 4 and an annular reflection surface 2. The circular transmission surface 4 is located in the ring of the annular reflection surface 2, and the distance between the inner edge of the annular reflection surface 2 and the optical axis is greater than or equal to the distance between the outer edge of the circular transmission surface 4 and the optical axis.

[0017] The optical path transmission process of the panoramic annular optical system is as follows: the incident light beam is incident into the panoramic head unit 13 through the annular transmission surface 1, and in the panoramic head unit 13, it is reflected by the annular reflection surface 2 and the circular reflection surface 3 in turn, and then emitted from the panoramic head unit 13 through the circular transmission surface 4; the light beam emitted from the circular transmission surface 4 is imaged on the image sensor 12 after being limited by the aperture diaphragm 8, converged by the relay lens group 14, and aberration corrected.

[0018] The first Q-con aspheric surface and the second Q-con aspheric surface have different calibers, and the caliber of the first Q-con aspheric surface is larger than that of the second Q-con aspheric surface. The first Q-con aspheric surface and the second Q-con aspheric surface have different calibers, but the surface shape formula is the same, that is, the sagittal expression of the first Q-con aspheric surface and the second Q-con aspheric surface is the same, and the sagittal expression z(ρ) is:

[0019]

[0020] Where {ρ, θ, z} is the cylindrical coordinate system coordinate of the first Q-con aspheric surface or the second Q-con aspheric surface, ρ 2 =x 2 +y 2 , ρ represents the semi-aperture, {x, y, z} are the rectangular coordinates of the first Q-con aspheric surface or the second Q-con aspheric surface, the straight line where the optical axis is located coincides with the z-axis, k is the cone coefficient, Qcon aspheric surface represents the first Q-con aspheric surface or the second Q-con aspheric surface, c is the vertex curvature radius of the Q-con aspheric surface, u is the normalized coordinate, -1≤u=ρ / ρ max ≤1,ρ max represents the maximum value of ρ, is an orthogonal polynomial, a m for The coefficient of m is any integer in [0, M], and M is an integer greater than 0. The first Q-con aspheric surface and the second Q-con aspheric surface are identical except for the caliber, which facilitates processing and improves processing efficiency.

[0021] Light rays with an angle range of X° to y° with the optical axis can be incident from the annular transmission surface 1 into the panoramic head unit 13, 42≥X>0, Y≥82, and the half field angle of the panoramic head unit 13 can be greater than 90°; in this embodiment, X=42, Y=82, and the half field angle range is 42°~82°. In this embodiment, the first Q-con aspherical surface also includes a first annular light absorption surface 5 located between the circular reflective surface 3 and the annular transmission surface 1, the outer edge of the first annular light absorption surface 5 is connected to the inner edge of the annular transmission surface 1, and the inner edge of the first annular light absorption surface 5 is connected to the outer edge of the circular reflective surface 3. The panoramic head unit 13 also includes a second annular light absorbing surface 6 located on the right side of the panoramic head unit 13, the annular reflective surface 2 is located in the ring of the second annular light absorbing surface 6, the distance between the outer edge of the annular reflective surface 2 and the optical axis is less than or equal to the distance between the inner edge of the second annular light absorbing surface 6 and the optical axis, specifically, the outer edge of the annular reflective surface 2 is connected to the inner edge of the second annular light absorbing surface 6, that is, the second annular light absorbing surface 6 and the second Q-con aspherical surface together serve as the right side surface of the panoramic head unit 13. The panoramic head unit 13 also includes a third annular light absorbing surface 7, the annular transmission surface 1 and the second annular light absorbing surface 6 are both located in the ring of the third annular light absorbing surface 7, specifically: the tangent plane of the third annular light absorbing surface 7 is parallel to the optical axis, and the third annular light absorbing surface 7 connects the annular transmission surface 1 and the second annular light absorbing surface 6. The above-mentioned first annular light absorbing surface 5, second annular light absorbing surface 6 and third annular light absorbing surface 7 are all used to absorb stray light.

[0022] The distance between two Q-con aspheric surfaces with the same parameters except the aperture is 20 mm, the radius of curvature c = 11.52 mm, the cone coefficient k = -0.82, and the maximum semi-aperture ρ max =26mm, the coefficients of each orthogonal polynomial are: a0=-9.97, a1=1.15, a2=0.397, a3=0.285, a4=0.248, a5=-0.396, the only difference between the two Q-con aspheric surfaces is that the aperture of the Q-con aspheric surface is 40.8mm, and the aperture of the second Q-con aspheric surface is 11.3mm.

[0023] The relay lens group has the functions of convergence and aberration correction. The relay lens group 14 includes a first double-cemented lens 9, a second double-cemented lens 10 and a field lens 11 arranged in sequence from left to right along the optical axis. The first double-cemented lens 9, the second double-cemented lens 10 and the field lens 11 all have a convergence effect on the light beam incident thereon from the left. The light beam emitted from the circular transmission surface 4 is sequentially limited by the aperture diaphragm 8, converged by the first double-cemented lens 9, converged by the second double-cemented lens 10, and converged by the field lens 11, and then imaged on the image sensor 12. The relay lens group 14 uses two double-cemented lenses and the field lens 11, which not only ensures the overall compactness and simplicity, but also reduces the chromatic aberration and other aberrations of the lens. The image sensor 12 can use but is not limited to CCD or CMOS.

[0024] Use Figure 1 With the structure shown, the above-mentioned Q-con aspheric parameters and the half field angle range of 42° to 82°, the optical system size (length from left to right) can be made less than 55mm. Figure 3 The half-field MTF diagram of the polychromatic light diffraction of the optical system of the present invention, T represents the meridian direction, S represents the sagittal direction, Figure 4 The point diagram corresponding to the wavelengths of 486.133nm, 587.562nm, and 656.273nm beams. The RMS radii corresponding to the five fields of view with small to large incident angles are 3.136um, 2.783um, 2.969um, 3.314um, and 2.956um, respectively. Figure 3 and Figure 4 It can be seen that the compact panoramic annular optical system of the present invention has excellent imaging quality and can meet the image quality requirements of the prior art.

[0025] The function of the panoramic head unit 13 of the present invention is mainly to refract and reflect the light of a large field of view and converge it to the relay lens group 14. In order to make the panoramic annular optical system compact, two Q-con aspheric surfaces with the same surface shape and rotational symmetry are brought into the panoramic head unit 13. The thickness and caliber of the Q-con aspheric surface are appropriately reduced to improve compactness under the system's permission, and in order to reduce costs, plastic materials such as polymethyl methacrylate (PMMA) can be used. Therefore, the compact panoramic annular optical system of the present invention realizes the compactness of the panoramic annular optical system as a whole through the design of the panoramic head unit 13, and has the advantages of wide field of view, small distortion, easy processing and manufacturing, and further compactness.

[0026] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A compact panoramic annular optical system, comprising a panoramic head unit (13), an aperture stop (8), a relay lens group (14) and an image sensor (12) arranged in sequence along an optical axis, wherein the panoramic head unit (13) is located on the left side of the aperture stop (8), It is characterized in that The panoramic head unit (13) comprises a first Q-con aspheric surface that is rotationally symmetrical and a second Q-con aspheric surface that is rotationally symmetrical. The first Q-con aspheric surface and the second Q-con aspheric surface have the same surface shape and are both convex to the left. The first Q-con aspheric surface is located on the left side surface of the panoramic head unit (13) and comprises a circular reflection surface (3) and an annular transmission surface (1). The circular reflection surface (3) is located in the ring of the annular transmission surface (1). The second Q-con aspheric surface is located on the right side surface of the panoramic head unit (13) and comprises a circular transmission surface (4) and annular reflection surface (2). The circular transmission surface (4) is located in the ring of the annular reflection surface (2). An incident light beam enters a panoramic head unit (13) through an annular transmission surface (1), is reflected by an annular reflection surface (2) and a circular reflection surface (3) in sequence, and then is emitted from the panoramic head unit (13) through a circular transmission surface (4). The light beam emitted from the circular transmission surface (4) is sequentially limited by an aperture diaphragm (8), converged by a relay lens group (14), and corrected for aberration before forming an image on an image sensor (12).

2. The compact panoramic annular optical system according to claim 1, It is characterized in that The vector height expression of the first Q-con aspheric surface and the second Q-con aspheric surface is the same, and the vector height expression z(ρ) is: Where, {ρ, θ, z} is the cylindrical coordinate system coordinate of the first Q-con aspheric surface or the second Q-con aspheric surface, ρ 2 =x 2 +y 2 , {x, y, z} are the rectangular coordinates of the first Q-con aspheric surface or the second Q-con aspheric surface, k is the cone coefficient, c is the radius of curvature of the aspheric vertex, u is the normalized coordinate, is an orthogonal polynomial, a m are orthogonal polynomial coefficients, m takes values ​​of all integers in [0, M], and M is an integer greater than 0.

3. The compact panoramic annular optical system according to claim 1, It is characterized in that The angle between the light incident on the annular transmission surface (1) and the optical axis is in the range of X° to Y°, where X≤42 and Y≥82.

4. The compact panoramic annular optical system according to claim 1, It is characterized in that The aperture of the first Q-con aspheric surface is larger than the aperture of the second Q-con aspheric surface.

5. The compact panoramic annular optical system according to claim 1, It is characterized in that The first Q-con aspherical surface further comprises a first annular light absorbing surface (5) located between the circular reflecting surface (3) and the annular transmitting surface (1), wherein the first annular light absorbing surface (5) connects the circular reflecting surface (3) and the annular transmitting surface (1).

6. The compact panoramic annular optical system according to claim 1, It is characterized in that The panoramic head unit (13) further comprises a second annular light absorbing surface (6) located on the right side of the panoramic head unit (13), and the annular reflecting surface (2) is located in the ring of the second annular light absorbing surface (6).

7. The compact panoramic annular optical system as claimed in claim 6, It is characterized in that The panoramic head unit (13) further comprises a third annular light absorbing surface (7), wherein the third annular light absorbing surface (7) connects the annular transmission surface (1) and the second annular light absorbing surface (6), and the annular transmission surface (1) and the second annular light absorbing surface (6) are both located in the ring of the third annular light absorbing surface (7).

8. The compact panoramic annular optical system as claimed in claim 1, It is characterized in that The relay lens group (14) comprises a first double-cemented lens (9), a second double-cemented lens (10) and a field lens (11) which are arranged in sequence from left to right along the optical axis. The first double-cemented lens (9), the second double-cemented lens (10) and the field lens (11) all have a converging effect on a light beam incident thereon from the left side.

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