An optical system for stereoscopic circular imaging

Abstract

The present invention discloses an optical system for stereoscopic circular viewing angle imaging, and belongs to the field of optical imaging technology. The optical system includes an imaging chip, a reflector group, and multiple image capturing optical paths. The multiple image capturing optical paths are evenly distributed in a circular shape with the reflector group as the center of the circle. Each reflector in the reflector group corresponds to the light emitting direction of each image capturing optical path, and reflects the light of each image capturing optical path to the imaging chip. The image capturing optical path includes a first lens, a second lens, a third lens, an aperture, a glued sheet, and a fourth lens, which are sequentially arranged and connected with the optical axis as the rotation center. External light is incident from the first lens, emitted from the fourth lens, and projected to the imaging chip after being reflected by the reflector group. The sum of the field angles of the multiple image capturing optical paths is greater than 360°. The system can realize stereoscopic circular viewing angle imaging in a static state through an imaging chip, which can greatly save the imaging cost of stereoscopic circumferential images.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical imaging, and relates to an optical system for stereoscopic circular viewing angle imaging, and in particular to a fixed-focus system for omnidirectional imaging in the field of security or smart home. Background Art

[0002] With the rapid development of security and smart home fields, the requirements for image and video information collection are getting higher and higher. How to balance the contradiction between the cost of the collection system and the integrity of the collected information is very important. How to obtain full-view image information without blind spots within a certain spatial range has always been a problem that needs to be solved in the industry. In response to the above problems, there are two traditional approaches: 1. Combination of multiple camera modules; 2. PTZ rotation collection. The first method uses a pair of camera modules, so the hardware cost and maintenance cost of the product are relatively high. The second method, due to the use of PTZ rotation collection, is difficult to implement image collection. Summary of the invention

[0003] In order to solve the problem of how to achieve 360-degree stereoscopic imaging without blind spots under static conditions through a set of imaging systems, the present invention provides an optical system for stereoscopic circular viewing angle imaging, and the technical solutions adopted are as follows:

[0004] An optical system for stereoscopic circular viewing angle imaging, the optical system comprises an imaging chip 7, a reflector group 6, and multiple image capturing light paths; the multiple image capturing light paths are evenly distributed in a circle with the reflector group 6 as the center; each reflector in the reflector group 6 corresponds to the light emitting direction of each image capturing light path, and reflects the light of each image capturing light path to the imaging chip; the image capturing light path comprises a first lens 1, a second lens 2, a third lens 3, an aperture, a glued sheet 4, and a fourth lens 5 which are sequentially arranged and connected with the optical axis as the rotation center; external light is incident from the first lens 1, emitted from the fourth lens 5, and projected to the imaging chip after being reflected by the reflector group 6; the total field of view angle of the multiple image capturing light paths is greater than 360°.

[0005] Preferably, the number of the plurality of image capturing optical paths is four; the reflector group 6 comprises four reflectors corresponding to the four image capturing optical paths respectively.

[0006] Preferably, the optical spacing between the first lens 1 and the second lens 2 is 5.86±0.03mm; the optical spacing between the second lens 2 and the third lens 3 is 0.484±0.03mm; the optical spacing between the third lens 3 and the aperture is 7.012±0.003mm; the optical spacing from the aperture to the adhesive sheet 4 is 0.1±0.03mm; the optical spacing between the adhesive sheet 4 and the fourth lens 5 is 0.1±0.02mm; the optical spacing between the fourth lens 5 and the image plane is 11±0.1mm; the total optical length from the front curvature center of the first lens 1 to the image plane is 38mm. The image plane refers to the surface of the imaging chip 7.

[0007] Preferably, the object surface of the first lens 1 is a convex spherical surface with a curvature radius of 20 mm, and the image surface is a concave spherical surface with a curvature radius of 4.7 mm; the object surface of the second lens 2 is a concave spherical surface with a curvature radius of 14.6 mm, and the image surface is a concave spherical surface with a curvature radius of 6.3 mm; the object surface of the third lens 3 is a convex spherical surface with a curvature radius of 7.5 mm, and the image surface is a convex spherical surface with a curvature radius of 33 mm; the object surface of the fourth lens 5 is a convex spherical surface with a curvature radius of 18.4 mm, and the image surface is a convex spherical surface with a curvature radius of 14.3 mm.

[0008] More preferably, the adhesive sheet 4 is formed by bonding two lenses, wherein the object surface of the first lens is a convex spherical surface with a curvature radius of 39 mm, and the image surface is a concave spherical surface with a curvature radius of 4 mm; the object surface of the second lens is a convex spherical surface with a curvature radius of 4 mm, and the mirror surface is a convex spherical surface with a curvature radius of 8.5 mm.

[0009] Preferably, it is characterized in that the surface tolerance of all curvatures is aperture 3-4, and the local aperture is 0.3-0.5.

[0010] Preferably, the focal length of the system is 2.6 mm, and the image plane diameter is 4.4 mm.

[0011] Preferably, the first lens 1 and the second lens 2 are made of heavy lanthanum flint glass; the third lens 3 is made of heavy flint glass; the first lens of the laminate is made of heavy phosphorus crown glass, and the second lens is made of heavy flint glass; the fourth lens is made of heavy flint glass.

[0012] More preferably, all lenses used are made of Chengdu Guangming colorless glass, wherein the first lens 1 is made of heavy lanthanum flint glass with a brand name of H-ZLAF891, the second lens 2 is made of heavy lanthanum flint glass with a brand name of H-ZLAF55D; the third lens 3 is made of heavy flint glass with a brand name of H-ZF72A; the first lens of the laminated sheet 4 is made of heavy phosphorus crown glass with a brand name of H-ZPK5, the second lens is made of heavy flint glass with a brand name of H-ZF62; the fourth lens 5 is made of heavy flint glass with a brand name of H-ZK21.

[0013] Preferably, the working environment is a visible light and near-infrared environment, and the working band is 485nm-850nm.

[0014] The object plane of the entire optical path structure is on the left, the initial focusing object distance is infinity, and the image plane is on the right, with an image distance of 11mm.

[0015] The present application defines that the left curvature of each lens is the object surface curvature of the lens, and the right curvature is the image surface curvature, and the curvature is positive when the convex surface faces the object surface and negative when the convex surface faces the image surface.

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

[0017] This application uses an imaging chip to expose and image a circular perspective image at one time through a special optical system. This does not increase the cost of the imaging hardware and can achieve circular perspective image capture in a static state. Through development in this way, more complete image information capture can be achieved at a lower cost in many security or smart homes and even smart robots in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a light path diagram (aperture stop omitted) of a single image capturing light path (plus a corresponding reflector) of an optical system in a preferred embodiment of the present invention.

[0019] Figure 2 This is a light path diagram of four image capture light paths in an optical system in a preferred embodiment of the present invention.

[0020] Figure 3 Based Figure 2 Schematic diagram of the three-dimensional structure of the middle reflector group.

[0021] Figure 4 A fan diagram of an optical system in a preferred embodiment of the present invention.

[0022] Figure 5 Graph showing distortion and field curvature of an optical system in a preferred embodiment of the present invention.

[0023] Figure 6 This is a graph showing the modulated optical transfer function of an optical system in a preferred embodiment of the present invention.

[0024] Figure 7 This is an image plane illumination curve diagram of an optical system in a preferred embodiment of the present invention.

[0025] Figure 8 It is a schematic diagram of a diffusion diagram of an optical system in a preferred embodiment of the present invention.

[0026] In the figure: 1, first lens; 2, second lens; 3, third lens; 4, adhesive sheet; 5, fourth lens; 6, reflector group; 61, transverse reflector; 62, longitudinal reflector; 7, imaging chip. DETAILED DESCRIPTION

[0027] Unless otherwise specified, the materials, methods and instruments used in the following examples are conventional materials, methods and instruments in the art and can be obtained by ordinary technicians in the art through commercial channels.

[0028] In the following description of the present invention, it should be noted that terms such as "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and "vertical" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and therefore, should not be understood as limiting the present invention.

[0029] In the following description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In addition, in the following description of the present invention, unless otherwise specified, “plurality”, “multiple groups”, and “multiple roots” mean two or more.

[0031] In the following embodiments, all lenses are made of Chengdu Guangming colorless glass, and are represented by Chengdu Guangming's brand. In order to ensure the subsequent industrial production, all brands are currently recommended for mass production. The imaging chip used is SONY's IMX334CMOS chip.

[0032] The present invention will be further described in detail below in conjunction with the accompanying drawings, but the following detailed description is not to be construed as limiting the present invention.

[0033] Figure 1 This is a light path diagram (without the aperture) of a single image capturing light path (plus the corresponding reflector) of an optical system in a preferred embodiment of the present invention. Figure 1It can be seen that the optical axis of the optical path is the first lens 1, the second lens 2, the third lens 3, the glue sheet 4, the fourth lens 5 and the reflector group 6 which are sequentially arranged and connected with each other as the rotation center. The light is reflected by the reflector group 6 and then projected onto the imaging chip 7. Among them, a stop (not shown) is also provided between the third lens 3 and the glue sheet 4.

[0034] Figure 2 This is a light path diagram of four image capturing light paths in an optical system in a preferred embodiment of the present invention. Figure 2 It can be seen that in this optical path system, there are a total of four image capture optical paths, and the four image capture optical paths are evenly distributed in a circular array with the reflector group 6 as the center, so as to fully capture image information in a 360-degree circular direction in four directions.

[0035] Figure 3 for Figure 2 Schematic diagram of the three-dimensional structure of the reflector group. Figure 3 It can be seen that the reflector group has a total of 4 reflectors, which are arranged in a rectangular shape. Among them, the two reflectors arranged diagonally are transverse reflectors 61, and the other two reflectors arranged diagonally are longitudinal reflectors 62. The four reflectors respectively reflect the four light rays upward to the imaging chip. Specific implementation method 1

[0037] This embodiment adopts Figure 1-3 The optical system is constructed by the optical path setting method shown. The main parameters of the optical system are the curvature, center thickness, aperture, optical spacing between lenses and the material of each lens, as follows:

[0038] The object plane of the entire optical path structure is on the left, the starting focusing object distance is infinity, the image plane is on the right, and the image distance is 11mm. We define the left curvature of each lens as the object surface curvature of the lens, and the right curvature as the image surface curvature. The curvature is positive when the convex side faces the object plane, and negative when the convex side faces the image plane.

[0039] The curvature surface data of each lens are as follows:

[0040] The object surface of lens 1 is a convex spherical surface with a curvature radius of 20mm, and the image surface is a concave spherical surface with a curvature radius of 4.7mm; the object surface of lens 2 is a concave spherical surface with a curvature radius of -14.6mm, and the image surface is a concave spherical surface with a curvature radius of 6.3mm; the object surface of lens 3 is a convex spherical surface with a curvature radius of 7.5mm, and the image surface is a convex spherical surface with a curvature radius of -33mm; the object surface of the first piece of laminated sheet 1 is a convex spherical surface with a curvature radius of 39mm, and the image surface is It is a concave spherical surface with a curvature radius of -4mm. The object surface of the second piece of laminated sheet 1 is a convex spherical surface, and its curvature is consistent with the image surface curvature of the first piece of laminated sheet 1. The image surface is a convex spherical surface with a curvature radius of -8.5mm. The object surface of lens 4 is a convex spherical surface with a curvature radius of 18.4mm, and the image surface is a convex spherical surface with a curvature radius of -14.3mm. The surface tolerance of all curvatures is aperture 3-4, and the local aperture is 0.3-0.5 (detected by interferometer).

[0041] The material data of each lens is as follows:

[0042] All lenses are made of Chengdu Guangming colorless glass and are indicated by Chengdu Guangming's brand names. In order to ensure subsequent industrial production, all brands are currently recommended for mass production.

[0043] Lens 1 is made of heavy lanthanum flint glass (H-ZLAF89L); lens 2 is made of heavy lanthanum flint glass (H-ZLAF55D); lens 3 is made of heavy flint glass (H-ZF72A); the first lens of the laminate 1 is made of heavy phosphorus crown glass (H-ZPK5), and the second lens is made of heavy flint glass (H-ZF62); lens 4 is made of heavy flint glass (H-ZK21);

[0044] refer to Figure 1 The system consists of 5 groups of 6 glass lenses and 1 plane reflector. The system aperture of the entire optical system is set between lens 3 and laminate 1. The total optical length of the system (from the center of the front curvature of the first lens to the image plane) is 38mm. The optical spacing from lens 1 to lens 2 is 5.86mm with a tolerance of ±0.03mm; the optical spacing from lens 2 to lens 3 is 0.484mm with a tolerance of ±0.03mm; the optical spacing from lens 3 to the aperture is 7.012mm with a tolerance of ±0.03mm; the optical spacing from the aperture to laminate 1 is 0.1mm with a tolerance of ±0.03mm; the optical spacing from laminate 1 to lens 4 is 0.1mm with a tolerance of ±0.02mm; the optical spacing from lens 4 to the image plane is 11mm with a tolerance of ±0.01mm.

[0045] The focal length of the system is 2.6mm, the image plane is 4.4mm in diameter, and it adopts a fixed-focus optical design. The system works in visible light and near-infrared environments, and the working band is between 485nm-655nm and 850nm.

[0046] In order to verify the image acquisition effect of the above optical system, the phase difference, distortion and field curvature, modulation optical transfer function, image plane illumination and confusion circle of the optical system were tested. The test results are as follows: Figure 4-8 shown.

[0047] Figure 4 FIG. 1 is a fan diagram of an optical system in a preferred embodiment of the present invention. Figure 4 As can be seen, the aberration set generated by 10 different fields of view is displayed, and the difference in meridian and sagittal aberrations can be seen in each field of view. As can be seen from the figure, the curve distribution of each view is very concentrated, indicating that the astigmatism is not large and the peripheral field of view is clear.

[0048] Figure 5 Figure 2 is a diagram of the distortion and field curvature of the optical system in a preferred embodiment of the present invention. Figure 5 It can be seen that this figure shows the field curvature and distortion of the system. The left side is the field curvature (image curvature). It can be seen from the figure that each curve represents a different wavelength. The maximum deviation of the image curvature will not be 0.05mm, which can be ignored. The right figure shows the optical distortion. The maximum distortion is less than 35%, which meets the design requirements.

[0049] Figure 6 FIG. 1 is a graph showing the modulated optical transfer function of an optical system in a preferred embodiment of the present invention. Figure 7 It can be seen that a form of expression that reflects the imaging quality of the entire imaging system, the horizontal axis is line pairs / mm, and the vertical axis is frequency. Different lines represent different fields of view and differences in meridians or sagittals.

[0050] Figure 7 FIG. 1 is an image plane illumination curve diagram of an optical system in a preferred embodiment of the present invention. Figure 7 It can be seen that the illumination at the center and edge of the imaging plane can reach more than 95% of the illumination at the center. The figure shows the attenuation of the light energy on the image plane from the center to the edge when the wavelength is 0.587μm, that is, the brightness uniformity of the image plane. Because the relative illumination of each field of view in this application changes very little, the curve is close to a straight line, and the value is almost 1.

[0051] Figure 8 FIG. 1 is a schematic diagram of a diffusion diagram of an optical system in a preferred embodiment of the present invention. Figure 8 It can be seen that all the pupil light rays in different field of view converge to the diffusion of the image plane.

[0052] Although the present invention has been disclosed as above in the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. An optical system for stereoscopic circular imaging, characterized in that: The invention comprises an imaging chip (7), a reflector group (6), and a plurality of image capturing optical paths; the plurality of image capturing optical paths are evenly distributed in a circular shape with the reflector group (6) as the center; each reflector in the reflector group (6) corresponds to the light emitting direction of each image capturing optical path, and reflects the light of each image capturing optical path to the imaging chip; the image capturing optical path comprises a first lens (1), a second lens (2), a third lens (3), an aperture, a bonding sheet (4), and a fourth lens (5) which are sequentially arranged and connected with the optical axis as the rotation center; external light is incident from the first lens (1), emitted from the fourth lens (5), and projected to the imaging chip after being reflected by the reflector group (6); the total field of view angle of the plurality of image capturing optical paths is greater than 360°; The optical spacing between the first lens (1) and the second lens (2) is 5.86±0.03mm; the optical spacing between the second lens (2) and the third lens (3) is 0.484±0.03mm; the optical spacing between the third lens (3) and the aperture is 7.012±0.003mm; the optical spacing from the aperture to the adhesive sheet (4) is 0.1±0.03mm; the optical spacing between the adhesive sheet (4) and the fourth lens (5) is 0.1±0.02mm; the optical spacing between the fourth lens (5) and the image plane is 11±0.1mm; the total optical length from the front curvature center of the first lens (1) to the image plane is 38mm; The object surface of the first lens (1) is a convex spherical surface with a curvature radius of 20 mm, and the image surface is a concave spherical surface with a curvature radius of 4.7 mm; the object surface of the second lens (2) is a concave spherical surface with a curvature radius of 14.6 mm, and the image surface is a concave spherical surface with a curvature radius of 6.3 mm; the object surface of the third lens (3) is a convex spherical surface with a curvature radius of 7.5 mm, and the image surface is a convex spherical surface with a curvature radius of 33 mm; the object surface of the fourth lens (5) is a convex spherical surface with a curvature radius of 18.4 mm, and the image surface is a convex spherical surface with a curvature radius of 14.3 mm; The glued sheet (4) is formed by laminating two lenses, wherein the object surface of the first lens is a convex spherical surface with a curvature radius of 39 mm, and the image surface is a concave spherical surface with a curvature radius of 4 mm; the object surface of the second lens is a convex spherical surface with a curvature radius of 4 mm, and the mirror surface is a convex spherical surface with a curvature radius of 8.5 mm.

2. The optical system for stereoscopic circular viewing angle imaging according to claim 1, characterized in that: The plurality of image capturing optical paths are four in number; the reflector group (6) comprises four reflectors corresponding to the four image capturing optical paths respectively.

3. The optical system for stereoscopic circular viewing angle imaging according to claim 1, characterized in that: The surface tolerance for all curvatures is aperture 3-4, and the local aperture is 0.3-0.

5.

4. The optical system for stereoscopic circular viewing angle imaging according to claim 1, characterized in that: The focal length of the system is 2.6 mm, and the image plane diameter is 4.4 mm.

5. The optical system for stereoscopic circular viewing angle imaging according to claim 1, characterized in that: The first lens (1) and the second lens (2) are made of heavy lanthanum flint glass; the third lens (3) is made of heavy flint glass; the first lens of the laminate is made of heavy phosphorus crown glass, and the second lens is made of heavy flint glass; the fourth lens is made of heavy flint glass.

6. The optical system for stereoscopic circular viewing angle imaging according to claim 5, characterized in that: All lenses used are made of Chengdu Guangming colorless glass, wherein the first lens (1) is made of heavy lanthanum flint glass with a brand number of H-ZLAF891, and the second lens (2) is made of heavy lanthanum flint glass with a brand number of H-ZLAF55D; the third lens (3) is made of heavy flint glass with a brand number of H-ZF72A; the first lens of the laminated sheet (4) is made of heavy phosphorus crown glass with a brand number of H-ZPK5, and the second lens is made of heavy flint glass with a brand number of H-ZF62; the fourth lens (5) is made of heavy flint glass with a brand number of H-ZK21.

7. The optical system for stereoscopic circular viewing angle imaging according to claim 1, characterized in that: The working environment is visible light and near-infrared environment, and the working band is 485nm-850nm.

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