WO2016115951A1 - 一种摄像机球罩 - Google Patents

一种摄像机球罩 Download PDF

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Publication number
WO2016115951A1
WO2016115951A1 PCT/CN2015/097196 CN2015097196W WO2016115951A1 WO 2016115951 A1 WO2016115951 A1 WO 2016115951A1 CN 2015097196 W CN2015097196 W CN 2015097196W WO 2016115951 A1 WO2016115951 A1 WO 2016115951A1
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WIPO (PCT)
Prior art keywords
edge portion
spherical portion
spherical
annular surface
sagittal direction
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PCT/CN2015/097196
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English (en)
French (fr)
Inventor
何品将
王威
刘超
沈辰弋
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杭州海康威视数字技术股份有限公司
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Priority to EP15878619.4A priority Critical patent/EP3249463B1/en
Priority to US15/536,498 priority patent/US10104274B2/en
Publication of WO2016115951A1 publication Critical patent/WO2016115951A1/zh

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B17/00—Details of cameras or camera bodies; Accessories therefor
    • G03B17/56—Accessories
    • G03B17/565—Optical accessories, e.g. converters for close-up photography, tele-convertors, wide-angle convertors
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B17/00—Details of cameras or camera bodies; Accessories therefor
    • G03B17/02—Bodies
    • G03B17/08—Waterproof bodies or housings
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B17/00—Details of cameras or camera bodies; Accessories therefor
    • G03B17/56—Accessories
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B17/00—Details of cameras or camera bodies; Accessories therefor
    • G03B17/56—Accessories
    • G03B17/561—Support related camera accessories

Definitions

  • the present invention relates to the field of optical imaging, and more particularly to a camera dome, and an optical imaging system therewith.
  • Transparent domes are widely used in optical imaging to provide mechanical protection for cameras and lenses, while also requiring excellent optical performance to minimize adverse effects on imaging.
  • Transparent covers for security applications are typically manufactured using high performance optical plastics. In order to make maximum use of the interior space, some of the transparent domes will be in the shape of a super hemisphere.
  • Such camera domes are typically manufactured using an injection molding process. In order to ensure the release performance, the camera dome cannot be made into a complete spherical surface.
  • the central area of the camera dome is usually machined into a spherical surface, and the edge area is machined into a conical surface.
  • the inner surface and the outer surface are concentric spherical surfaces; in the edge region of the dome, the inner surface and the outer surface are tapered surfaces.
  • the conical surface and the spherical surface are connected by a tangent method, and the thickness is kept uniform, so that the processing is simple and the central portion has good image quality.
  • the inherent defect of such a dome is that the curvature of the conical surface is different in the direction of the midday and the sagittal direction, and the power in the two directions is also different.
  • the beam passes through the dome, its meridional direction and sagittal direction
  • the beam is not focused at the same point, which causes the image to appear blurred, resulting in significant astigmatism, affecting the imaging effect, especially in optical systems with long focal length and large aperture. Because of the astigmatism defects, the application of the camera dome is greatly limited.
  • Another technique is to use a blow molding process to make a completely concentric spherical camera dome.
  • a concentric spherical camera dome has a uniform power, because the radius of curvature of the meridional and sagittal directions is the same, the generation of astigmatism is avoided, and there is no problem of demolding.
  • the uniformity of the wall thickness of the dome cover is poor, and the image quality is poor, which is difficult to meet the requirements of the high definition imaging optical system.
  • Power is the ability of an optical component to converge or diverge light, usually the reciprocal of its focal length.
  • Astigmatism is a type of optical imaging aberration. After the beam passes through the optical element, the beams in the meridional and sagittal directions are not focused at the same point, causing blurring of the image, which is called astigmatism.
  • the meridional direction in this context refers specifically to the direction of the gyroscopic geometry along its generatrix.
  • the sagittal direction refers in this paper to the direction of the rotary geometry along the circumference of the rotation, and the sagittal direction is perpendicular to the meridional direction and the rotary axis.
  • the annular surface is a type of optical surface that is equivalent to the surface of a normal tire.
  • An important characteristic of the toroidal surface is that the meridional and sagittal directions have different radii of curvature.
  • the present invention provides a camera dome including a spherical portion at a center of the camera dome and an edge portion connected thereto, the inner surface and the outer surface of the edge portion being rotated a face, and a rotation axis of the edge portion is parallel to a rotation axis of the spherical portion, the inner surface of the inner surface is monotonously increased in a direction away from the spherical portion from a portion connected to the spherical portion,
  • the power in the meridional direction and the sagittal direction of the edge portion are the same as the power in the meridional direction and the sagittal direction of the spherical portion.
  • the meaning of “equal” includes “substantially equal” and “close”, for example, the difference between the difference between the two values and the larger of the two is less than 10%. In the case of the case, it is considered “equal”.
  • an inner surface of the edge portion is a conical surface, and the conical surface is tangentially connected to an inner surface of the spherical portion;
  • an outer surface of the edge portion is an annular surface, and the outer surface of the annular surface and the spherical portion The faces are tangently connected.
  • the inner surface of the edge portion is a conical surface, and the bus bar of the conical surface is rotated outward by a correction angle with respect to a tangent line at the joint portion of the inner surface of the spherical portion, wherein the correction angle is greater than 0 degrees and Less than or equal to 3 degrees;
  • the outer surface of the edge portion is an annular surface that is tangentially connected to the outer surface of the spherical portion.
  • the curvature of the meridional direction of the annular surface is equal to the difference between the curvature of the conical surface and the annular surface in the sagittal direction.
  • an angle between the generatrix of the conical surface and the axis of rotation of the edge portion (B) is greater than or equal to 0.1 degrees and less than or equal to 30 degrees. Further preferably, it is 15 degrees or less.
  • an inner surface of the edge portion is an annular surface, and the annular surface is tangentially connected to an inner surface of the spherical portion; an outer surface of the edge portion is a conical surface, and the outer surface of the conical surface and the spherical portion The faces are tangently connected.
  • the generatrix of the conical surface is rotated inward by a correction angle with respect to a tangent to the outer surface of the spherical portion at the joint portion, wherein the correction angle is greater than 0 degrees and less than or equal to 3 degrees.
  • the curvature of the annular surface in the meridional direction is the same as the difference between the curvature of the annular surface and the conical surface in the sagittal direction.
  • the inner surface of the edge portion is a first annular surface, the first annular surface is tangentially connected to the inner surface of the spherical portion;
  • the outer surface of the edge portion is a second annular surface, the second annular surface The face is tangentially connected to the outer surface of the spherical portion.
  • the difference between the curvature of the first annular surface and the second annular surface in the meridional direction is the same as the difference between the curvature of the first annular surface and the second annular surface in the sagittal direction.
  • the present invention sets the power in the meridional direction and the sagittal direction of the edge portion of the camera dome to be the same as that of the spherical portion, the beam in the meridional direction and the sagittal direction of the dome can be focused to the same after the beam passes through the dome.
  • the astigmatism generated in the prior art due to the failure of the meridional direction and the sagittal direction to focus on the same point is eliminated, which provides favorable conditions for obtaining clear imaging.
  • the present invention also provides an optical imaging system comprising a camera dome as described above.
  • FIG. 1 is a schematic structural view of a camera dome according to the present invention.
  • a camera dome includes a spherical portion at the center of the camera dome and an edge portion coupled to the spherical portion.
  • An inner surface and an outer surface of the edge portion are a revolving surface, and an axis of rotation of the edge portion is parallel to a rotation axis of the spherical portion, the inner surface being away from the spherical surface from a connection with the spherical portion
  • the radius of gyration monotonously increases, and the powers in the meridional direction and the sagittal direction of the edge portion are the same as the powers in the meridional direction and the sagittal direction of the spherical portion.
  • the present invention sets the power in the meridional direction and the sagittal direction of the edge portion of the camera dome to be the same as that of the spherical portion, the beam in the meridional direction and the sagittal direction of the dome can be focused to the same after the beam passes through the dome.
  • the astigmatism generated in the prior art due to the failure of the meridional direction and the sagittal direction to focus on the same point is eliminated, which provides favorable conditions for obtaining clear imaging.
  • the camera dome (hereinafter simply referred to as a dome) has a rotationally symmetrical structure and has a rotary axis O.
  • the dome includes a central region and an edge region connected thereto.
  • the central region is formed by the spherical portion A, that is, the inner surface 1 and the outer surface 2 are both spherical, and the inner surface 1 and the outer surface 2
  • the spherical centers coincide, that is, the two spheres are concentric, so that after the beam passes through the spherical portion A, the beam in the meridional direction and the sagittal direction of the spherical portion A can be focused to the same point without astigmatism and the image is clear.
  • the edge region is located on the outer circumference of the central region, corresponding to the edge portion B.
  • the spherical portion A and the edge portion B have different powers in the meridional direction, so that the beams of the dome in the meridional direction and the sagittal direction are not focused at the same point, and astigmatism is generated.
  • the present invention sets the spherical portions A and the edge portions B to have the same or substantially the same power in the meridional direction and the sagittal direction to avoid the astigmatism problem of the prior art as much as possible. .
  • the power in the meridional direction of the edge portion B is the same as the power in the meridional direction of the spherical portion A
  • the power in the sagittal direction of the edge portion B is the same as the power in the sagittal direction of the spherical portion A.
  • the beam in the meridional direction and the sagittal direction of the entire dome of the super hemispherical structure can be focused to the same point, eliminating the prior art due to the meridional direction and the sagittal direction.
  • the astigmatism that can be focused on the same point provides advantages for clear imaging.
  • power refers to the ability of an optical element to converge or diverge light.
  • the same refractive index requirements of the spherical portion A and the edge portion B can be satisfied.
  • the power in the meridional direction of the edge portion B is the same as the power in the meridional direction of the spherical portion A, and the power in the sagittal direction of the edge portion B
  • the power in the sagittal direction of the spherical portion A is the same.
  • the power in the meridional direction of the edge portion B is approximately equal to the superposition of the power in the meridional direction of the inner surface 3 of the edge portion B and the outer surface 4, and the power in the sagittal direction of the edge portion B is approximately equal to the edge portion B.
  • the spherical portions A and the edge portions B can be made to have the same power in the meridional direction and the sagittal direction.
  • the following is through several embodiments. Explain the implementation of the second point.
  • the inner surface 3 of the edge portion B employs a conical surface which is tangentially connected or nearly tangential to the inner surface 1 of the spherical portion A so that a certain curvature can be introduced in the sagittal direction.
  • the outer surface 4 of the edge portion B is an annular surface which is tangentially connected to the outer surface 2 of the spherical portion A.
  • the annular surface has different curvatures in the meridional direction and the sagittal direction, so that both the meridional direction and the sagittal direction can be Introduce different curvatures.
  • the combined power is consistent with the power of the spherical portion A in the meridional direction and the sagittal direction, respectively, and the dome is optically equivalent to one super.
  • the sphere-shaped dome of the hemisphere so whether from the spherical portion A or the edge portion B, the beam can always be focused to the same point in the meridional direction and the sagittal direction, thereby avoiding the generation of astigmatism.
  • the curvature of the conical surface (inner surface 3) in the meridional direction is zero, the curvature in the sagittal direction is the reciprocal of the radius of gyration; the curvature in the sagittal direction of the annular surface (outer surface 4) is the reciprocal of the radius of gyration, in the meridional direction
  • the curvature is close to the difference between the curvature of the conical surface and the annular surface in the sagittal direction.
  • the inner surface 3 (conical surface) of the edge portion B is nearly tangentially connected to the inner surface 1 of the spherical portion A, meaning that the generatrix of the conical surface is tangent to the inner surface 1 of the spherical portion A at the joint portion.
  • the correction angle is greater than 0 degrees and less than or equal to 3 degrees.
  • the correction angle is 0.2 degrees. The reason for setting the above correction angle is due to the following considerations.
  • the horizontal principal ray deflection angle of the penetrating edge portion B changes, and when adjusted to a certain smaller value, the incident chief ray and the exiting chief ray of the edge portion B remain. parallel. At this point, correcting the angle will not affect the overall power and astigmatism of the dome, while at the same time compensating for the slightest light. Deviation, which achieves excellent imaging results.
  • the conical surface and the inner surface 1 of the spherical portion A are not completely tangent to each other, but can be close to the tangent connection.
  • the angle between the generatrix of the conical surface and the axis of rotation of the edge portion (B) is greater than or equal to 0.1 degrees and less than or equal to 30 degrees to facilitate demolding.
  • the larger the angle the easier it is to remove the film during processing; however, too large an angle causes the diameter of the edge portion to increase too fast, making the total volume of the dome too large. Therefore, it is preferable that the angle between the bus bar of the conical surface and the rotation axis of the edge portion (B) is 15 degrees or less.
  • the inner surface 3 of the edge portion B adopts an annular surface which is tangentially connected to the inner surface 1 of the spherical portion A, and the annular surface has different curvatures in the meridional direction and the sagittal direction, so that both the meridional direction and the sagittal direction can be Introduce different curvatures.
  • the outer surface 4 of the edge portion B is a conical surface which is tangentially connected or nearly tangent to the outer surface 2 of the spherical portion A so that a certain curvature can be introduced in the sagittal direction.
  • the combined power is consistent with the power of the spherical portion A in the meridional direction and the sagittal direction, respectively, and the dome is optically equivalent to one super.
  • the sphere-shaped dome of the hemisphere so whether from the spherical portion A or the edge portion B, the beam can always be focused to the same point in the meridional direction and the sagittal direction, thereby avoiding the generation of astigmatism.
  • the curvature in the meridional direction of the annular surface (inner surface 3) is close to the difference between the curvature of the annular surface and the conical surface in the sagittal direction, and the curvature in the sagittal direction is the reciprocal of the radius of gyration.
  • the curvature of the conical surface (outer surface 4) in the meridional direction is zero, and the curvature in the sagittal direction is the reciprocal of the radius of gyration.
  • the outer surface 4 (conical surface) of the edge portion B is nearly tangentially connected to the outer surface 2 of the spherical portion A, meaning that the generatrix of the conical surface is inwardly tangential to the outer surface 2 of the spherical portion A at the joint portion.
  • Rotate a correction angle Preferably, the correction angle is greater than 0 degrees and less than or equal to 3 degrees.
  • the correction angle is greater than 0 degrees and less than or equal to 3 degrees.
  • the correction angle is 0.2 degrees. The reason for setting the above correction angle is due to the following considerations.
  • the conical surface and the inner surface 1 of the spherical portion A are not completely tangent to each other, but can be close to the tangent connection.
  • the inner surface 3 of the edge portion B adopts a first annular surface which is tangentially connected to the inner surface 1 of the spherical portion A.
  • the first annular surface has different curvatures in the meridional direction and the sagittal direction, so that the meridional direction can be Different curvatures are introduced in both the sagittal direction.
  • the outer surface 4 of the edge portion B is a second annular surface which is tangentially connected to the outer surface 2 of the spherical portion A, so that different curvatures can also be introduced in both the meridional direction and the sagittal direction.
  • the combined power is consistent with the power of the spherical portion A in the meridional direction and the sagittal direction, respectively, and the dome is optically equivalent to one super.
  • the sphere-shaped dome of the hemisphere so whether from the spherical portion A or the edge portion B, the beam can always be focused to the same point in the meridional direction and the sagittal direction, thereby avoiding the generation of astigmatism.
  • the curvature of the first annular surface (inner surface 3) in the sagittal direction is the reciprocal of the radius of gyration
  • the curvature of the second annular surface (outer surface 4) in the sagittal direction is the reciprocal of the radius of gyration.
  • the difference between the curvatures of the first annular surface and the second annular surface in the meridional direction is close to the difference between the curvatures of the two in the sagittal direction.
  • the inner surface 3 and the outer surface 4 of the edge portion B may also be curved surfaces of other shapes.
  • the bus bar of the inner surface is composed of a first straight line segment and a first circular arc line
  • the bus bar of the outer surface is composed of a second circular arc line and a second straight line segment.
  • the busbar of the inner surface is composed of a plurality of arc lines of different radii
  • the busbars of the outer surface are also composed of arc lines of different radii.
  • the "main ray” mentioned above refers to light passing through the center of the sphere of the dome and horizontally.
  • proximity means approximately or substantially equal.
  • the present invention also provides an optical imaging system comprising at least the dome of the above embodiments, and other portions of the optical imaging system are prior art and will not be described again.

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Abstract

一种摄像机球罩，包括位于中心的球面部分(A)及与之连接的边缘部分(B)，所述边缘部分(B)的内表面(3)和外表面(4)为回转面，且其回转轴线平行于所述球面部分(A)的回转轴线，所述内表面(3)在从与所述球面部分(A)连接处向远离所述球面部分(A)的方向上，回转半径单调增大，所述边缘部分(B)的子午方向和弧矢方向的光焦度均与所述球面部分(A)相同。由于该球罩将摄像机球罩边缘部分(B)的子午方向和弧矢方向的光焦度设置成与球面部分(A)的相同，因此光束通过球罩后，球罩的子午方向和弧矢方向的光束能够聚焦到同一点上，消除了现有技术中由于子午方向和弧矢方向未能聚焦到同一点所产生的像散，为获得清晰的成像提供有利条件。

Description

一种摄像机球罩 技术领域
本发明涉及光学成像领域，特别是涉及一种摄像机球罩，及具有其的光学成像系统。
背景技术
透明球罩广泛应用于光学成像领域，主要为摄像机和镜头提供机械保护，同时需要具备优良的光学性能，以将对成像的不利影响减至最小。安防领域用的透明罩通常使用高性能的光学塑料制造。为了最大限度地利用内部空间，部分透明球罩会做成超半球的形状。
此种摄像机球罩通常采用注塑工艺制造。为了保证脱模性能，摄像机球罩不能做成完全的球面。通常将摄像机球罩的中心区域加工成球面，边缘区域加工成圆锥面。此类球罩的中心区域，为了保证良好的光学性能，内表面和外表面均采用同心球面；在球罩的边缘区域，内表面和外表面则都采用圆锥面。圆锥面和球面部分通过相切的方式连接，厚度保持均匀，从而具有加工简单，中心部分像质良好的特点。
但此类球罩的固有缺陷在于圆锥面因子午方向和弧矢方向的曲率不同，两个方向上的光焦度也随之产生差异，光束通过球罩后，其子午方向和弧矢方向的光束未聚焦在同一点上，使得成像出现模糊，产生显著像散，影响成像效果，在长焦距大口径的光学系统上尤为严重。因为存在像散的缺陷，摄像机球罩的应用场合受到很大限制。
另外一种技术是利用吹塑工艺，来制造完全是同心球面型的摄像机球罩。此种同心球面型的摄像机球罩具有一致的光焦度，因为子午和弧矢方向的曲率半径相同，避免了像散的产生，同时也不存在脱模的问题。但受吹塑工艺技术特点的限制，此种球罩的壁厚均匀度不佳，成像质量很差，难以满足高清成像光学系统的要求。
因此希望有一种技术方案来克服或至少减轻现有技术的上述缺陷中的一 个或多个。
发明内容
术语解释
光焦度是指光学元件会聚或者发散光线的能力，通常为其焦距的倒数。
像散是光学成像像差的一种。光束通过光学元件后，其子午和弧矢方向的光束未聚焦在同一点上，使得成像出现模糊，此种像差称为像散。
子午方向在本文中特指回转几何体沿其母线的方向。
弧矢方向在本文中特指回转几何体沿旋转圆周的方向，弧矢方向垂直于子午方向和回转轴。
环形面是光学曲面的一种，形状相当于普通轮胎表面。环形面的重要特性为子午和弧矢方向具有不同的曲率半径。
本发明的目的在于提供一种摄像机球罩来克服或至少减轻现有技术的上述缺陷中的一个或多个。
为实现上述目的，本发明提供一种摄像机球罩，所述摄像机球罩包括位于所述摄像机球罩中心的球面部分及与之连接的边缘部分，所述边缘部分的内表面和外表面为回转面，且所述边缘部分的回转轴线平行于所述球面部分的回转轴线，所述内表面在从与所述球面部分连接处向远离所述球面部分的方向上，回转半径单调增大，所述边缘部分的子午方向和弧矢方向的光焦度均与所述球面部分的子午方向和弧矢方向的光焦度相同。需要指出的是，在本发明中，“相等”的含义包括“大致相等”和“接近”，举例而言，在两个值的差与两者中较大值的比值的绝对值小于10％的情况下，认为是“相等的”。
优选地，所述边缘部分的内表面为圆锥面，该圆锥面与所述球面部分的内表面相切连接；所述边缘部分的外表面为环形面，该环形面与所述球面部分的外表面相切连接。
优选地，所述边缘部分的内表面为圆锥面，该圆锥面的母线相对于所述球面部分的内表面在连接部位处的切线向外旋转一个修正角度，其中所述修正角度大于0度且小于等于3度；所述边缘部分的外表面为环形面，该环形面与所述球面部分的外表面相切连接。
优选地，所述环形面的子午方向的曲率等于所述圆锥面和所述环形面在弧矢方向的曲率之差。
优选地，所述圆锥面的母线和所述边缘部分(B)的回转轴线的之间的夹角大于等于0.1度，小于等于30度。进一步优选地，小于等于15度。
优选地，所述边缘部分的内表面为环形面，该环形面与所述球面部分的内表面相切连接；所述边缘部分的外表面为圆锥面，该圆锥面与所述球面部分的外表面相切连接。
优选地，所述圆锥面的母线相对于所述球面部分的外表面在连接部位处的切线向内旋转一个修正角度，其中所述修正角度大于0度且小于等于3度。
优选地，所述环形面的子午方向的曲率与所述环形面和所述圆锥面在弧矢方向的曲率之差相同。
优选地，所述边缘部分的内表面为第一环形面，该第一环形面与所述球面部分的内表面相切连接；所述边缘部分的外表面为第二环形面，该第二环形面与所述球面部分的外表面相切连接。
优选地，所述第一环形面和所述第二环形面在子午方向的曲率之差与所述第一环形面和所述第二环形面在弧矢方向的曲率之差相同。
由于本发明将摄像机球罩边缘部分的子午方向和弧矢方向的光焦度设置成与球面部分的相同，因此光束通过球罩后，球罩的子午方向和弧矢方向的光束能够聚焦到同一点上，消除了现有技术中由于子午方向和弧矢方向未能聚焦到同一点所产生的像散，为获得清晰的成像提供有利条件。
本发明还提供一种光学成像系统，所述光学成像系统包括如上所述摄像机球罩。
附图说明
图1为本发明所提供摄像机球罩的结构示意图。
附图标记：
Figure PCTCN2015097196-appb-000001
Figure PCTCN2015097196-appb-000002
具体实施方式
为使本发明实施的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行更加详细的描述。在附图中，自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。所描述的实施例是本发明一部分实施例，而不是全部的实施例。下面通过参考附图描述的实施例是示例性的，旨在用于解释本发明，而不能理解为对本发明的限制。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。下面结合附图对本发明的实施例进行详细说明。
在本发明的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明保护范围的限制。
根据本发明的摄像机球罩包括位于摄像机球罩中心的球面部分及与球面部分连接的边缘部分。所述边缘部分的内表面和外表面为回转面，且所述边缘部分的回转轴线平行于所述球面部分的回转轴线，所述内表面在从与所述球面部分连接处向远离所述球面部分的方向上，回转半径单调增大，所述边缘部分的子午方向和弧矢方向的光焦度均与所述球面部分的子午方向和弧矢方向的光焦度相同。
由于本发明将摄像机球罩边缘部分的子午方向和弧矢方向的光焦度设置成与球面部分的相同，因此光束通过球罩后，球罩的子午方向和弧矢方向的光束能够聚焦到同一点上，消除了现有技术中由于子午方向和弧矢方向未能聚焦到同一点所产生的像散，为获得清晰的成像提供有利条件。
如图1所示，摄像机球罩(下文中简称为球罩)采用回转对称的结构形式，具有回转轴O。球罩包括中心区域和与之连接的边缘区域。中心区域由球面部分A形成，即内表面1和外表面2都采用球面，并且内表面1和外表面2 的球心重合，即两球面同心，因此光束通过球面部分A后，球面部分A的子午方向和弧矢方向的光束能够聚焦到同一点上，无像散，成像清晰。边缘区域位于中心区域的外周，对应于边缘部分B。现有技术中球面部分A和边缘部分B在子午方向光焦度不相同，因此使得球罩在子午方向和弧矢方向的光束未能聚焦在同一点，而产生像散。
鉴于此，本发明将球面部分A和边缘部分B在子午方向和弧矢方向的光焦度均设置成相同或大致相同，以尽量避免现有技术的像散问题。。
具体地，边缘部分B的子午方向的光焦度与球面部分A的子午方向的光焦度相同，边缘部分B的弧矢方向的光焦度与球面部分A的弧矢方向的光焦度相同。
因此，光束通过本发明所提供的球罩后，整个超半球结构的球罩的子午方向和弧矢方向的光束能够聚焦到同一点上，消除了现有技术中由于子午方向和弧矢方向未能聚焦到同一点所产生的像散，为获得清晰的成像提供有利条件。
上述“光焦度”指的是光学元件会聚或者发散光线的能力。光焦度的计算公式为:光焦度＝n’/f’＝(n’-n)*C，式中，n和n’分别是表面两侧的折射率(空气一侧为1)，C为表面的曲率，f’为焦距。也就是说，光焦度与表面两侧的折射率n、n’和表面的曲率C相关，由此，边缘部分B的光焦度的控制可以延伸出两方面的要求：
其一、通过将球面部分A和边缘部分B使用相同的制作材料，便可以满足球面部分A和边缘部分B的折射率相同的要求。
其二、通过控制球面部分A和边缘部分B的曲率，使边缘部分B的子午方向的光焦度与球面部分A的子午方向的光焦度相同，边缘部分B的弧矢方向的光焦度与球面部分A的弧矢方向的光焦度相同。而边缘部分B的子午方向的光焦度近似等于边缘部分B的内表面3和外表面4的子午方向的光焦度的叠加，边缘部分B的弧矢方向的光焦度近似等于边缘部分B的内表面3和外表面4的弧矢方向的光焦度的叠加。
在满足第一点的要求的基础上，再满足第二点，便可以实现球面部分A和边缘部分B在子午方向和弧矢方向的光焦度均相同。下面通过若干实施例来 说明第二点的实现方式。
实施例1：
边缘部分B的内表面3采用圆锥面，该圆锥面与球面部分A的内表面1相切连接或者接近相切连接，从而可以在弧矢方向引入一定的曲率。边缘部分B的外表面4为环形面，该环形面与球面部分A的外表面2相切连接，环形面在子午方向和弧矢方向具有不同的曲率，从而可以在子午方向和弧矢方向均引入不同的曲率。通过将内表面3和外表面4组合起来，组合后的光焦度在子午方向和弧矢方向分别与球面部分A的光焦度一致，此时的球罩在光学特性上等效于一个超半球的球面面型的球罩，因此无论从球面部分A，还是边缘部分B，光束在子午方向和弧矢方向始终能够聚焦到同一点上，避免了像散的产生。
圆锥面(内表面3)的子午方向的曲率为零，弧矢方向的曲率为其回转半径的倒数；环形面(外表面4)的弧矢方向的曲率为其回转半径的倒数，子午方向的曲率接近圆锥面和环形面在弧矢方向的曲率之差。通过将圆锥面和环形面在子午方向和环形面的光焦度叠加后，可以看出，边缘部分B的光焦度则与球面部分A保持大致相同，即所述边缘部分的子午方向和弧矢方向的光焦度均与所述球面部分相同，从而较好地消除了像散。
边缘部分B的内表面3(圆锥面)与球面部分A的内表面1接近相切连接，是指该圆锥面的母线相对于所述球面部分A的内表面1在连接部位处的切线向外旋转一个修正角度。有利的是，所述修正角度大于0度且小于等于3度。例如，在一个实施例中，所述修正角度为0.2度。之所以设置上述的修正角度是出于下述考虑。
在实际应用时，对于圆锥面与球面部分A的内表面1相切连接的技术方案，检测到：水平方向主光线通过边缘部分B的内表面3和外表面4时，会产生大约0.03°左右的偏差。如果用在长焦距的光学成像系统上，该偏差对成像会产生一些不利的影响。通过设置所述修正夹角，可以补偿该偏差。由于内表面3是圆锥面，因此改变修正角度即是微量修正圆锥面的圆锥度。随着内表面3的圆锥度的变化，穿透边缘部分B的水平主光线偏角随之改变，当调节到某个特定较小的值时，边缘部分B的入射主光线和出射主光线保持平行。此时，修正夹角既不会影响球罩整体的光焦度和像散特性，同时又能补偿光线的轻微 偏角，从而实现了优良的成像效果。
需要说明的是，一旦存在上述“修正夹角”，则上述圆锥面与球面部分A的内表面1之间无法完全相切，但是能够接近相切连接。
有利的是，所述圆锥面的母线和所述边缘部分(B)的回转轴线的之间的夹角大于等于0.1度，小于等于30度，从而便于脱模。角度越大，在加工中越容易实现脱膜；但角度太大会导致边缘部分的口径增加过快，从而使得球罩的总体积过大。因此，优选的是，所述圆锥面的母线和所述边缘部分(B)的回转轴线的之间的夹角小于等于15度。
实施例2：
边缘部分B的内表面3采用环形面，该环形面与球面部分A的内表面1相切连接，环形面在子午方向和弧矢方向具有不同的曲率，从而可以在子午方向和弧矢方向均引入不同的曲率。边缘部分B的外表面4为圆锥面，该圆锥面与球面部分A的外表面2相切连接或者接近相切连接，从而可以在弧矢方向引入一定的曲率。通过将内表面3和外表面4组合起来，组合后的光焦度在子午方向和弧矢方向分别与球面部分A的光焦度一致，此时的球罩在光学特性上等效于一个超半球的球面面型的球罩，因此无论从球面部分A，还是边缘部分B，光束在子午方向和弧矢方向始终能够聚焦到同一点上，避免了像散的产生。
环形面(内表面3)的子午方向的曲率接近环形面和圆锥面在弧矢方向的曲率之差，弧矢方向的曲率为其回转半径的倒数。圆锥面(外表面4)的子午方向的曲率为零，弧矢方向的曲率为其回转半径的倒数。通过将环形面和圆锥面在子午方向和环形面的光焦度叠加后，可以看出，边缘部分B的光焦度则与球面部分A保持相同，从而消除了像散。
边缘部分B的外表面4(圆锥面)与球面部分A的外表面2接近相切连接，是指该圆锥面的母线相对于所述球面部分A的外表面2在连接部位处的切线向内旋转一个修正角度。优选地，所述修正角度大于0度且小于等于3度。有利的是，所述修正角度大于0度且小于等于3度。例如，在一个实施例中，所述修正角度为0.2度。之所以设置上述的修正角度是出于下述考虑。
在实际应用时，对于圆锥面与球面部分A的外表面2相切连接的技术方案，水平方向主光线通过边缘部分B的内表面3和外表面4时，会产生大约 0.03°左右的偏差。如果用在长焦距的光学成像系统上，该偏差对成像会产生一些不利的影响。设置上述修正夹角可以补偿该偏差。随着该修正夹角的变化，穿透边缘部分B的光线偏角随之改变，当调节到某个特定较小的值时，边缘部分B的入射主光线和出射主光线保持平行。此时，修正夹角既不会影响球罩整体的光焦度和像散特性，同时又能补偿光线的轻微偏角，从而实现了优良的成像效果。
需要说明的是，一旦存在上述“修正夹角”，则上述圆锥面与球面部分A的内表面1之间无法完全相切，但是能够接近相切连接。
实施例3：
边缘部分B的内表面3采用第一环形面，第一环形面与球面部分A的内表面1相切连接，第一环形面在子午方向和弧矢方向具有不同的曲率，从而可以在子午方向和弧矢方向均引入不同的曲率。边缘部分B的外表面4为第二环形面，该第二环形面与球面部分A的外表面2相切连接，从而也可以在子午方向和弧矢方向均引入不同的曲率。通过将内表面3和外表面4组合起来，组合后的光焦度在子午方向和弧矢方向分别与球面部分A的光焦度一致，此时的球罩在光学特性上等效于一个超半球的球面面型的球罩，因此无论从球面部分A，还是边缘部分B，光束在子午方向和弧矢方向始终能够聚焦到同一点上，避免了像散的产生。
第一环形面(内表面3)的弧矢方向的曲率为其回转半径的倒数，第二环形面(外表面4)的弧矢方向的曲率为其回转半径的倒数。第一环形面和第二环形面在子午方向的曲率之差接近两者在弧矢方向的曲率之差。通过将第一环形面和第二环形面在子午方向和环形面的光焦度叠加后，可以看出，边缘部分B的光焦度则与球面部分A保持相同，从而消除了像散。
实质上，边缘部分B的内表面3和外表面4还可以是其它形状的曲面。例如，内表面的母线由第一直线段及第一圆弧线组成，外表面的母线由第二圆弧线及第二直线段组成。再例如，内表面的母线由多段不同半径的圆弧线组成，外表面的母线也由不同半径的圆弧线组成。在此不再一一列举，只要保证内表面3和外表面4的总光焦度与球面部分A在子午方向和弧矢方向上分别相同即可。
上述提及的“主光线”指的是通过球罩的球心、且方向为水平的光线。
上述提及的“接近”的意思是近似或基本相等。
本发明还提供一种光学成像系统，其至少包括上述各实施例中的球罩，所述光学成像系统中的其它部分均为现有技术，在此不再展开描述。
最后需要指出的是：以上实施例仅用以说明本发明的技术方案，而非对其限制。尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的精神和范围。

Claims (10)

  1. 一种摄像机球罩，其包括位于所述摄像机球罩中心的球面部分(A)及与所述球面部分(A)连接的边缘部分(B)，其特征在于：所述边缘部分(B)的内表面和外表面为回转面，且所述边缘部分(B)的回转轴线平行于所述球面部分的回转轴线，所述内表面在从与所述球面部分连接处向远离所述球面部分的方向上，回转半径单调增大，所述边缘部分(B)的子午方向和弧矢方向的光焦度均与所述球面部分(A)的子午方向和弧矢方向的光焦度相同。
  2. 如权利要求1所述的摄像机球罩，其特征在于：所述边缘部分(B)的内表面(3)为圆锥面，该圆锥面与所述球面部分(A)的内表面(1)相切连接；所述边缘部分(B)的外表面(4)为环形面，该环形面与所述球面部分(A)的外表面(2)相切连接。
  3. 如权利要求1所述的摄像机球罩，其特征在于：所述边缘部分(B)的内表面(3)为圆锥面，该圆锥面的母线相对于所述球面部分(A)的内表面(1)在连接部位处的切线向外旋转一个修正角度，其中所述修正角度大于0度且小于等于3度；所述边缘部分(B)的外表面(4)为环形面，该环形面与所述球面部分(A)的外表面(2)相切连接。
  4. 如权利要求2或3所述的摄像机球罩，其特征在于：所述环形面的子午方向的曲率等于所述圆锥面和所述环形面在弧矢方向的曲率之差。
  5. 如权利要求2或3所述的摄像机球罩，其特征在于：所述圆锥面的母线和所述边缘部分(B)的回转轴线之间的夹角大于等于0.1度，小于等于30度。
  6. 如权利要求1所述的摄像机球罩，其特征在于：所述边缘部分(B)的内表面(3)为环形面，该环形面与所述球面部分(A)的内表面(1)相切连接；所述边缘部分(B)的外表面(4)为圆锥面，该圆锥面与所述球面部分 (A)的外表面(2)相切连接。
  7. 如权利要求6所述的摄像机球罩，其特征在于：所述圆锥面的母线相对于所述球面部分(A)的外表面(2)在连接部位处的切线向内旋转一个修正角度，其中所述修正角度大于0度且小于等于3度。
  8. 如权利要求7所述的摄像机球罩，其特征在于：所述环形面的子午方向的曲率与所述环形面和所述圆锥面在弧矢方向的曲率之差相同。
  9. 如权利要求1所述的摄像机球罩，其特征在于：所述边缘部分(B)的内表面(3)为第一环形面，该第一环形面与所述球面部分(A)的内表面(1)相切连接；所述边缘部分(B)的外表面(4)为第二环形面，该第二环形面与所述球面部分(A)的外表面(2)相切连接。
  10. 如权利要求9所述的摄像机球罩，其特征在于：所述第一环形面和所述第二环形面在子午方向的曲率之差与所述第一环形面和所述第二环形面在弧矢方向的曲率之差相同。
PCT/CN2015/097196 2015-01-22 2015-12-11 一种摄像机球罩 WO2016115951A1 (zh)

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EP3249463A1 (en) 2017-11-29
CN105873383B (zh) 2018-10-26
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