JP2020042197A - Lens device and imaging apparatus having the same - Google Patents

Abstract

To provide a lens device having two optical systems capable of forming an image on a single imaging device and capable of obtaining high-quality images with a wide-angle of view.SOLUTION: A lens device 100 has two optical systems 101, 102. Each of the two optical systems 101, 102 has two lens surfaces of a curvature different from each other in two directions perpendicular to the optical axis. Two images by two optical systems 101 and 102 are formed on a single imaging device. Since the image circle of each optical system is formed elliptical, two image circles can be formed on one rectangular imaging device; and thus, the efficiency of using the pixels of the imaging device can be increased.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens device, and is suitable for an imaging device such as a digital video camera, a digital still camera, a broadcast camera, a silver halide film camera, and a surveillance camera.

  2. Description of the Related Art In order to shoot a video used for a content that provides a sense of reality, such as virtual reality, an imaging device that can perform wide-angle and stereoscopic shooting is required.

  Patent Literature 1 discloses an imaging apparatus having a configuration in which three-dimensional imaging is enabled by forming an optical image by two optical systems on one imaging element.

JP 2012-3022 A

  However, the imaging device described in Patent Document 1 has a configuration in which only a part of an image circle formed by two optical systems is cut out and used to efficiently use an imaging surface to obtain a high-quality image. It has become. For this reason, it was difficult for the imaging device of Patent Document 1 to acquire a wide-angle image (video).

  An object of the present invention is to obtain a high-quality image with a wide angle of view in a lens device having two optical systems capable of forming an image on one image sensor.

  The lens device of the present invention has two optical systems, each of the two optical systems has two lens surfaces having different curvatures in two directions perpendicular to the optical axis. It is characterized in that two images can be formed on one image sensor.

  According to the present invention, a high-quality image with a wide angle of view can be obtained in a lens device having two optical systems capable of forming an image on one image sensor.

It is principal part sectional drawing of a lens apparatus. FIG. 2 is a diagram schematically illustrating an image circle formed by two optical systems on one image sensor. FIG. 2 is a cross-sectional view of the optical system according to the first embodiment. FIG. 3 is an aberration diagram of the optical system according to the first embodiment. FIG. 9 is a cross-sectional view of an optical system according to a second embodiment. FIG. 9 is an aberration diagram of the optical system according to the second embodiment. FIG. 10 is a cross-sectional view of the optical system according to a third embodiment. FIG. 10 is an aberration diagram of the optical system according to the third embodiment. FIG. 14 is a sectional view of an optical system according to a fourth embodiment. FIG. 14 is an aberration diagram of the optical system according to the fifth embodiment. It is a schematic diagram of an imaging device.

  Hereinafter, embodiments of a lens device of the present invention and an imaging device having the same will be described with reference to the accompanying drawings.

[Example 1]
FIG. 1 is a sectional view of a main part of the lens device according to the first embodiment.

  As shown in FIG. 1, the lens device 100 of the present embodiment has two optical systems 101 and 102. The optical systems 101 and 102 are held by a casing (not shown). In the present embodiment, the optical systems 101 and 102 are the same except for the reflection direction of a reflective member described later, and thus the optical system 101 will be described as a representative in the following description.

  The optical system 101 has two reflecting members 103 and 105. The first reflecting member 103 has a reflecting surface R1 that bends the optical path. The second reflecting member 105 has a reflecting surface R2 that bends the optical path. An aperture stop SP is provided between the first reflecting member 103 and the second reflecting member 105.

  In FIG. 1, IP denotes an image plane (a paraxial imaging position). An image sensor such as a CCD sensor or a CMOS sensor or a film is arranged on the image plane IP.

  An image (optical image) is formed on the image plane IP by the optical systems 101 and 102. That is, in the lens device 100 of the present embodiment, two optical images by the two optical systems are formed on one image sensor.

  FIG. 2A is a diagram schematically illustrating an image circle formed by the optical systems 101 and 102 of the lens device 100 according to the present embodiment. A rectangular area shown in FIG. 2A represents an effective area of the image sensor, and an ellipse represents an image circle. As shown in FIG. 2A, the shape of the image circle of the optical systems 101 and 102 of the present embodiment is not a circle but an ellipse.

  2 (a) and 2 (c), a description will be given of the technical effect of the lens device 100 of the present embodiment in which the shape of the image circle is elliptical.

  Consider a case where two images obtained by two optical systems are acquired by one image sensor. If the aspect ratio of the image sensor is 1: 2, the image sensor is divided into two square areas, and each image circle is inscribed in each square area, so that pixels can be used without waste. However, the aspect ratio of a general image sensor is 2: 3 or 3: 4. In this case, as shown in FIG. 2B, if the image circle diameters of the two optical systems are each set to half the length of the long side of the image sensor, an area not used for photographing on the image sensor (the gray area in FIG. 2B) (Area indicated by). For this reason, some of the pixels on the image sensor are wasted. On the other hand, as shown in FIG. 2C, when the image circle diameters of the two optical systems are each equal to the short side of the image sensor, the use efficiency of the pixels of the image sensor is improved, but the angle of view in the horizontal direction is reduced. Would. For this reason, an image (video) having a sufficiently wide angle of view cannot be obtained.

  For this reason, in this embodiment, the image circles of the two optical systems 101 and 102 are arranged side by side in a direction parallel to the long side of one rectangular image sensor, and each image circle has an elliptical shape. As a result, two image circles can be accommodated in one rectangular image sensor, and the efficiency of using pixels of the image sensor can be increased. As a result, a high-quality image (video) with a wide angle of view can be obtained.

  The optical system 101 of this embodiment is configured to have at least two lens surfaces having different curvatures in two different directions perpendicular to the optical axis in order to make the image circle oval. The lens surfaces having different curvatures in two different directions perpendicular to the optical axis include, for example, an anamorphic surface and a toric surface. The reason why two or more such lens surfaces are provided is to correct the deviation of the imaging position while changing the focal length in two different directions perpendicular to the optical axis. Note that the optical axis refers to the central axis of the optical system. Therefore, when the optical system 101 includes a reflecting member as in the present embodiment, the optical axis is bent in the optical system.

  In the lens device 100 of the present embodiment, with the above configuration, an image with a wide angle of view and high image quality can be obtained while an image can be formed on one image sensor.

  Next, the optical system 101 of the present embodiment will be described.

  FIG. 3 is a sectional view of the optical system 101 of the present embodiment. However, the optical path bent by the reflecting members 103 and 105 is shown in an expanded manner. FIG. 3A is a cross-sectional view of the XY section, and FIG. 3B is a cross-sectional view of the XZ section. Here, the axes X, Y, and Z correspond to the axes in FIG. That is, the Z axis is an axis in a direction in which the optical systems 101 and 102 are arranged (a direction perpendicular to both axial rays incident on the most object-side surfaces of the optical systems 101 and 102). The X-axis is an axis parallel to the on-axis ray incident on the most object-side surfaces of the optical systems 101 and 102, and the Y-axis is an axis perpendicular to the Z-axis and the X-axis. Hereinafter, a direction parallel to the Z axis is also referred to as a horizontal direction (first direction), and a direction parallel to the Y axis is also referred to as a vertical direction (second direction). Note that the on-axis light beam is a light beam that reaches the image plane through the optical axis in the optical system 101.

  The optical system 101 according to the present embodiment includes a plurality of lenses and reflecting members 103 and 105. In this embodiment, the first reflecting member 103 and the second reflecting member 105 are both prisms, but may be simple mirrors. When a prism is used as the reflecting member, the light incident surface and the light emitting surface may be flat or curved.

  In the present embodiment, an image sensor (length / width ratio: 2: 3) having a horizontal length of 36 mm and a vertical length of 24 mm is used. For this reason, the space on the image sensor that can be used by one optical system has a horizontal length of 18 mm and a vertical length of 24 mm. Here, a space of 0.25 mm is left, right, up and down in consideration of an optical axis shift due to a manufacturing error and image interference due to leakage light of an adjacent lens. Therefore, the horizontal length of the image circle of one optical system is 17.5 mm, and the vertical length is 23.5 mm.

  Further, the optical system 101 of the present embodiment is a fisheye lens having a maximum angle of view of 180 ° by conformal projection. Conformal projection is a projection method in which the relationship of y = fθ holds when the half image height is y, the half angle of view is θ, and the focal length is f.

  Here, assuming that the horizontal focal length of the optical system 101 is fz and the vertical focal length is fy, fz = 5.57 mm and fy = 7.48 mm from the relational expression of y = fθ and the size of the image circle. Is obtained. That is, an aspheric surface having different curvatures in two directions perpendicular to the optical axis may be introduced so that fy and fz have such values.

  In the present embodiment, the anamorphic surfaces are provided as aspheric surfaces AS having different curvatures in two directions perpendicular to the optical axis, that is, on a ninth surface, a sixteenth surface, a twenty-fifth surface, and a twenty-seventh surface in total. Both anamorphic surfaces have different curvatures in the horizontal and vertical directions.

  In the optical system 101 of the present embodiment, the object side to the first reflecting member 103 are formed by a negative meniscus lens having a convex surface on the object side, a negative meniscus lens having a convex surface on the object side, a biconcave lens, a biconcave lens, and a positive meniscus lens having a biconvex lens and the object side convex surface. It consists of a cemented lens and a biconvex lens. An aspherical surface is arranged on the object side of the second negative lens to correct astigmatism and distortion which are problems in a wide-angle lens. An anamorphic surface is arranged on the image side surface of the cemented lens.

  Further, between the first reflection member 103 and the second reflection member 105, from the object side, a cemented lens of a negative meniscus lens having a convex surface on the object side and a positive meniscus lens having a convex surface on the object side, and an aperture SP are arranged. The image side surface of the cemented lens is an anamorphic surface.

  In addition, from the object side, from the object side, a cemented lens of a biconvex lens and a negative meniscus lens having a convex surface on the image side, a biconvex lens, a negative meniscus lens having a convex surface on the object side, and an anamorphic lens having a convex surface on the image side from the object side. It is composed of a lens having an aspherical surface. An anamorphic surface is also arranged on the object side surface of the negative meniscus lens having a convex surface on the object side.

  In this embodiment, four anamorphic aspherical surfaces are arranged. In particular, the anamorphic aspherical surface used for the final lens has a large curvature difference, and the final lens has a horizontal focal length of -125.3 mm and a vertical focal length of 42.2 mm.

  In this embodiment, the projection system of the optical system 101 is conformal projection. However, another projection system may be used. In addition, in consideration of the interference of the image circle, etc., a space of 0.25 mm is secured on the upper, lower, left, and right sides of the image circle. However, it is possible to arbitrarily set whether or not to provide the space and how much the space is. .

  The distance (base length) of the optical axis of the two optical systems 101 and 102 on the lens surface closest to the object in the lens device 100 of this embodiment is 61.97 mm.

  FIG. 4 is an aberration diagram of the optical system 101 according to the present embodiment when focused on infinity. 4A is an aberration diagram in the horizontal direction, FIG. 4B is an aberration diagram in the vertical direction, and FIG. 4C is an aberration diagram in an oblique direction that forms an angle of 45 ° with the horizontal direction.

  In each aberration diagram, Fno is an F number, and ω is a half angle of view (°). In the spherical aberration diagram, the solid line represents the spherical aberration at the d-line (wavelength 587.6 nm), and the broken line represents the spherical aberration at the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line (ΔS) represents the astigmatism of the sagittal image plane at the d-line, and the broken line (ΔM) represents the astigmatism of the meridional image plane at the d-line. The distortion diagram shows the d-line distortion. The chromatic aberration diagram shows the chromatic aberration of the g-line. The same applies to the following aberration diagrams.

  Next, conditions that are preferably satisfied by the lens device 100 of the present embodiment will be described.

  It is preferable that the image circle of the optical system 101 has a shape in which the vertical length is longer than the horizontal length as in the present embodiment. That is, it is preferable to arrange the aspherical surfaces AS having different curvatures in two directions perpendicular to the optical axis so that the image circle is enlarged in the vertical direction (or reduced in the horizontal direction). This makes it possible to increase the efficiency of using pixels when an image is formed by the two optical systems 101 and 102 on one image sensor having a general shape.

  Further, the optical system 101 preferably has three or more aspheric surfaces having different curvatures in two directions perpendicular to the optical axis, such as an anamorphic surface. As a result, the degree of freedom in aberration correction can be improved, and as a result, sufficiently high optical performance can be obtained even in oblique directions.

  In addition, it is preferable that the optical system 101 be configured to include the stop SP, and to have at least one aspheric surface having different curvatures in two directions perpendicular to the optical axis on at least one light incident side and one light exit side of the stop SP. In the optical system 101 according to the present embodiment, the reflecting members 103 and 105 are disposed before and after the stop SP, and a lens on the opposite side of the stop with respect to the reflecting member has two axes perpendicular to the optical axis. The height at which external light passes through the lens is different. Therefore, by arranging aspheric surfaces having different curvatures in two directions perpendicular to the optical axis at such positions, it is possible to easily control the optical characteristics independently in the two directions.

  Further, it is preferable that the optical system 101 has at least two reflecting members that bend the optical path as in this embodiment.

  The lens apparatus 100 of the present embodiment has a configuration in which two optical systems 101 and 102 are horizontally arranged for one image sensor, thereby enabling stereoscopic imaging.

  In order to obtain a highly realistic three-dimensional image (video) with the lens device 100, it is preferable to increase the distance (base line length) between the optical axes on the incident side of the two optical systems 101 and 102 during shooting. If the base line length is too short, there is no parallax between the optical systems 101 and 102, and the stereoscopic effect may be insufficient. Generally, the distance between the human eyes is about 60 mm, and in order to capture a highly realistic image, it is preferable that the two optical systems have a base line length close to the distance between the human eyes.

  On the other hand, in the lens device 100 of the present embodiment, one image sensor acquires images by the two optical systems 101 and 102, but the size of a general image sensor is significantly smaller than 60 mm. For this reason, simply arranging the optical systems 101 and 102 with respect to the image sensor may result in an insufficient base line length. Therefore, as shown in FIG. 1, by bending the optical path at least twice, the base line length of the two optical systems 101 and 102 can be increased. As a result, it is possible to obtain an image (video) capable of obtaining a sufficient three-dimensional effect, and it is possible to obtain a high sense of realism. Note that the reflecting member may be the prism of the present embodiment or a simple mirror.

  If the base line length is too long, the parallax is too large, and when observing a shadow image, the stereoscopic effect is emphasized, and the possibility that the observer feels tired increases. In addition, as the deviation between the base line length and the distance between human eyes increases, the deviation from the three-dimensional sensation based on human bodily sensation and experience increases, causing a sense of incongruity. Therefore, the base line length is more preferably 40 mm or more and 70 mm or less.

  When two reflecting members for bending the optical path are provided in the optical system 101, the two reflecting members are preferably provided between two aspheric surfaces having different curvatures in two directions perpendicular to the optical axis of the two surfaces. As described above, it is preferable that the aspherical surfaces having different curvatures in the two directions perpendicular to the optical axis be arranged at positions where the light of each angle of view is separated (toward the object side or the image side of the optical system 101). On the other hand, in order to reduce the size of the reflection member, it is preferable to arrange the reflection member at a position where light rays concentrate. Therefore, by arranging the two reflecting members and the two aspheric surfaces as described above, it is possible to simultaneously achieve high optical performance and downsizing of the lens device 100.

When the entire angle of view of the optical system 101 is AV, it is preferable that the following conditional expression is satisfied.
150 ° <AV <190 ° (1)

  Equation (1) defines the angle of view of the optical system 101 necessary to obtain a higher realistic image (video). If the value exceeds the upper limit value of conditional expression (1), an image (video) having a sufficient angle of view can be obtained, but the size of the optical system increases, which is not preferable. If the lower limit of conditional expression (1) is not reached, the angle of view becomes too small. For example, when observing an image (video) obtained using the lens device 100 on a head-mounted display, there is an area without an image in the peripheral portion. Will increase. In this case, it is not preferable because high realism cannot be obtained.

It is more preferable that the numerical value range of the conditional expression (1) be in the range of the following conditional expression (1a), and it is even more preferable that the numerical value range of the conditional expression (1b) be in the following range.
155 ° <AV <187 ° (1a)
160 ° <AV <185 ° (1b)

When the horizontal focal length of the optical system 101 is fh and the vertical focal length is fv, it is preferable that the following conditional expression (2) is satisfied. Here, the horizontal focal length is a focal length in a direction perpendicular to both axial rays incident on the most object-side surfaces of the optical system 101 and the optical system 102. The horizontal focal length is defined as a straight line perpendicular to an axial ray incident on the most object-side surfaces of the optical systems 101 and 102, and a focal point in a direction perpendicular to the axial ray. Distance.
0.55 <fh / fv <0.90 (2)

  When the value goes below the lower limit of conditional expression (2), the difference between the focal length in the vertical direction and the focal length in the horizontal direction increases, and it becomes difficult to sufficiently increase the optical performance in the oblique direction. Further, in order to enhance the optical performance in the oblique direction, a large number of anamorphic surfaces, toric surfaces and the like are required. When the value exceeds the upper limit of conditional expression (2), the image circle becomes too close to a circle, and the pixels on the image sensor cannot be used sufficiently effectively.

It is more preferable that the numerical value range of the conditional expression (2) is in the range of the following conditional expression (2a), and it is more preferable that the numerical value range of the conditional expression (2b) is in the following range.
0.60 <fh / fv <0.88 (2a)
0.70 <fh / fv <0.86 (2b)

  Next, another embodiment having a different configuration of the optical system will be described.

  As in the first embodiment, the lens device of the second embodiment is used for an image sensor (aspect ratio 2: 3) having a horizontal length of 36 mm and a vertical length of 24 mm. Therefore, similarly to the first embodiment, the focal length of the optical system of the second embodiment is fz = 5.57 mm and fy = 7.48 mm.

  FIG. 5 is a cross-sectional view of the optical system 101 in the lens device according to the second embodiment. The optical system according to the second embodiment differs from the first embodiment in the configuration particularly from the second reflecting member 105 to the image plane. In the second embodiment, a cemented lens of a biconvex lens and a negative meniscus lens having a convex surface on the image side, a biconvex lens, a negative meniscus lens having a convex surface on the object side, and two cylindrical lenses are provided between the second reflecting member 105 and the image surface from the object side. Has been arranged. An anamorphic surface is arranged on the object side surface of the negative meniscus lens having a convex surface on the object side.

  In the first embodiment, an anamorphic surface having a large difference in curvature is used for the final lens. However, it is generally difficult to mold a surface having a large difference in curvature on one surface. Therefore, in Example 2, two cylindrical surfaces having a curvature only in the horizontal direction and a cylindrical surface having the curvature only in the vertical direction were used. In the case of an anamorphic lens, it is possible to make a curvature difference on one surface in the horizontal and vertical directions, so that the number of lenses can be reduced. However, the cost can be reduced because the cylindrical lens is easy to process. When a cylindrical lens is used, the number of lenses increases. Therefore, the degree of freedom in design can be further improved by selectively using an anamorphic lens and a cylindrical lens. In the second embodiment, the anamorphic lens and the cylindrical lens are combined, but it is also possible to realize only with the cylindrical lens.

  In addition, the base line length in the lens device of Example 2 is 61.97 mm.

  In the second embodiment, two cylindrical lenses are joined, but they may be separated.

  FIG. 6 is an aberration diagram of the optical system 101 according to the second embodiment when focused on infinity. 6A is an aberration diagram in the horizontal direction, FIG. 6B is an aberration diagram in the vertical direction, and FIG. 6C is an aberration diagram in a direction forming an angle of 45 ° with the horizontal direction.

  In the optical system according to the third embodiment, unlike the first and second embodiments, an image sensor (aspect ratio 9:16) having a horizontal length of 24 mm and a vertical length of 14 mm is used. For this reason, the space on the image sensor that can be used by one optical system has a horizontal length of 12 mm and a vertical length of 14 mm. Here, a space of 0.25 mm is left, right, up and down in consideration of an optical axis shift due to a manufacturing error and image interference due to leakage light of an adjacent lens. Therefore, the horizontal length of the image circle of one optical system is 11.5 mm, and the vertical length is 13.5 mm.

  The optical system according to the third embodiment is a fisheye lens having a maximum angle of view of 180 ° in conformal projection. Therefore, from the relational expression of y = fθ and the size of the image circle, the focal length of the optical system of this embodiment is obtained as fz = 3.66 mm and fy = 4.30 mm.

  FIG. 7 is a sectional view of the optical system 101 in the lens device according to the third embodiment. In the optical system 101 according to the third embodiment, from the object side to the first reflecting member 103, a negative meniscus lens having a convex surface on the object side, a negative meniscus lens having a convex surface on the object side, a cemented lens of a biconvex lens and a biconcave lens, and a negative lens having a convex image side are provided. It consists of a meniscus lens and a biconvex lens. An aspherical surface is arranged on the object side of the second negative lens to correct astigmatism and distortion which are problems in a wide-angle lens. The object side surface of the cemented lens and the object side surface of the biconvex lens disposed on the object side of the first reflecting member 103 are anamorphic surfaces.

  In the optical system 101 according to the third embodiment, an aperture stop SP and a cemented lens of a negative meniscus lens having a convex surface on the object side and a convex lens are arranged between the first reflection member 103 and the second reflection member 105 from the object side. . The image side surface of the cemented lens is an anamorphic surface.

  In the optical system according to the third embodiment, a cemented lens of a biconvex lens and a biconcave lens, a biconvex lens, a negative meniscus lens having a convex surface on the object side, and a convex lens on the image side are located between the second reflective element and the image plane from the object side. A positive meniscus lens having an anamorphic surface on the side is arranged. An aspherical surface is arranged on the object side surface of the cemented lens, and spherical aberration and coma are corrected well.

  The base line length in the lens device according to the third embodiment is 50.00 mm.

  FIG. 8 is an aberration diagram of the optical system 101 according to the third embodiment when focused on infinity. 8A is an aberration diagram in the horizontal direction, FIG. 8B is an aberration diagram in the vertical direction, and FIG. 8C is an aberration diagram in a direction forming an angle of 45 ° with the horizontal direction.

  FIG. 9 is a cross-sectional view of the optical system 101 in the lens device according to the fourth embodiment. In the fourth embodiment, unlike the first to third embodiments, a mirror is used as a reflecting member instead of a prism. The imaging device used in the lens device of the fourth embodiment is the same as that of the third embodiment, but the base line length is slightly different, and is 49.96 mm.

  FIG. 10 is an aberration diagram of the optical system 101 of Example 4 upon focusing on infinity. 10A is an aberration diagram in the horizontal direction, FIG. 10B is an aberration diagram in the vertical direction, and FIG. 10C is an aberration diagram in a direction forming an angle of 45 ° with the horizontal direction.

  Next, Numerical Embodiments 1 to 4 corresponding to the optical systems of Embodiments 1 to 4 will be described. Each numerical example represents an infinity in-focus condition. In each numerical example, the surface number is the order of the optical surface when counted from the object side. r is the radius of curvature of the i-th optical surface (i-th surface) counted from the object side, and d is the distance between the i-th surface and the (i + 1) -th surface. nd and νd are the refractive index and Abbe number of the lens with respect to the d-line.

In each numerical example, an asterisk (*) is added to the aspheric lens surface after the surface number. In the surface data, the radius of curvature is indicated by ANA for the anamorphic surface and the radius of curvature is indicated by CYL for the cylindrical surface. In addition, “e ± P” in each aspheric coefficient means “× 10 ^{± P} ”.

  Hereinafter, a method of expressing an aspherical shape will be described.

First, an aspherical surface whose curvature does not change depending on the direction (an aspherical surface whose contour lines are concentric circles) will be described. The displacement amount from the surface vertex in the optical axis direction is x, the height from the optical axis in the direction perpendicular to the optical axis direction is h, the paraxial radius of curvature is R, the conic constant is k, and the aspheric coefficients are A4 and A6. A8 and A10. At this time, such an aspherical shape is represented by the following equation.
^{x = (h 2 / R)} / [1+ {1- (1 + k) (h / R) 2} 1/2] + A4 × h 4 + A6 × h 6 + A8 × h 8 + A10 × h 10

  Next, the anamorphic surface will be described. When the optical axis is x, the vertical direction is y, and the horizontal direction is z, the anamorphic surface is a surface for both a surface relative coordinate system xy plane and an xz plane with respect to a quadratic surface-based general aspheric surface. An aspheric surface that is symmetric, but not always rotationally symmetric. Alternatively, the cut surface of the curved surface in a plane parallel to the xy plane is a plane that changes according to the value of z. Such an anamorphic surface can be represented by the following equation.

Ry, Rz: Reference radii of curvature in the Y and Z directions Ky, Kz: Conical constants C1 to C8, C1p to C8p: Aspherical coefficients related to y and z

  Next, the cylindrical surface will be described. As an optical element that changes the curvature in the horizontal direction and the vertical direction, there is a toric surface. Among the toric surfaces, a surface having a curvature in only one of the Y direction and the Z direction is a cylindrical surface. When the bus formula X is represented by the coordinate system X, Y, Z in the cross section of the surface of such a surface, it is as follows.

R: reference curvature radius in the bus direction Ky: conic constant in the bus direction B2 to B16: aspheric coefficient according to the bus equation Y

  When the sagittal equation S is represented by the coordinate system X, Y, Z in the sagittal section, the following is obtained.

r: reference radius of curvature in the sagittal direction Kz: conical constant in the sagittal direction D2 to D16: aspheric coefficient according to the sagittal equation Z

Using the generatrix system X and the sagittal system S, the toric surface can be represented by the following equation.
x = X + Scos θ
y = Y-Ssin θ

[Numerical Example 1]
Unit: mm

Surface data Surface number rd nd νd Effective diameter
1 32.469 1.75 2.00100 29.1 38.31
2 11.638 9.95 22.68
3 * 41.489 0.95 1.85400 40.4 19.28
4 13.154 7.04 16.52
5 -21.899 1.00 1.69680 55.5 15.10
6 41.414 1.01 15.18
7 -285.328 0.80 1.84666 23.9 15.24
8 14.008 4.18 1.85025 30.1 15.89
9 * ANA 0.21 16.29
10 47.107 3.56 2.00069 25.5 16.58
11 -27.234 1.00 16.70
12 ∞ 16.00 1.51633 64.1 15.51
13 ∞ 1.50 10.15
14 14.666 1.00 2.00069 25.5 9.01
15 13.132 1.84 1.55332 71.7 8.64
16 * ANA 1.95 8.48
17 (aperture) 1.00 1.00 8.26
18 ∞ 13.40 1.51633 64.1 8.13
19 ∞ 0.50 10.37
20 * 18.737 3.92 1.58313 59.4 11.25
21 -9.708 1.50 1.80610 33.3 11.48
22 -199.058 0.10 12.56
23 38.792 3.36 1.43875 94.7 12.97
24 -19.630 0.15 13.40
25 * ANA 0.75 1.85478 24.8 13.55
26 17.422 3.05 13.32
27 * ANA 2.62 1.80400 46.6 13.54
28 -26.269 15.92 15.01
Image plane ∞

Aspheric surface 3rd surface
K = 0.00000e + 000 A 4 = -4.22996e-006 A 6 = -1.02464e-007 A 8 = 3.41693e-010 A10 = -3.73367e-012

Side 20
K = 0.00000e + 000 A 4 = -5.44196e-005 A 6 = 1.93654e-007 A 8 = -6.59703e-010 A10 = 1.25172e-011

Anamorphic surface data surface 9
Ry = 7.68429e + 001 Rz = 1.98978e + 002 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

16th page
Ry = 6.49486e + 001 Rz = 2.22931e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Side 25
Ry = 3.00175e + 001 Rz = 2.99452e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Surface 27
Ry = -1.99087e + 001 Rz = -1.10875e + 002 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Various data
Vertical direction Horizontal direction Oblique 45 ° focal length 7.44 5.57 6.61
F-number 4.00 2.81 3.48
Half angle of view 90 ° 90 ° 90 °
Half height 11.75 8.75 10.38
Total lens length 100.00 100.00 100.00
BF 15.92 15.92 15.92

[Numerical example 2]
Unit: mm

Surface data Surface number rd nd νd Effective diameter
1 30.884 1.75 2.00100 29.1 37.35
2 11.363 9.12 22.14
3 * 31.829 0.95 1.85400 40.4 19.09
4 11.281 7.23 15.91
5 -20.245 1.00 1.72916 54.7 14.64
6 47.372 0.80 14.82
7 1825.982 0.80 1.84666 23.9 14.90
8 11.998 4.56 1.85025 30.1 15.57
9 * ANA 0.89 15.95
10 50.335 3.56 2.00069 25.5 16.57
11 -26.276 0.99 16.71
12 ∞ 16.00 1.51633 64.1 15.50
13 ∞ 1.50 10.19
14 12.789 1.00 2.00100 29.1 9.24
15 10.258 2.08 1.55332 71.7 8.87
16 * ANA 1.71 8.68
17 (aperture) ∞ 1.00 8.46
18 ∞ 13.40 1.51633 64.1 8.32
19 ∞ 0.53 10.26
20 * ANA 4.14 1.58313 59.4 10.98
21 -7.927 1.00 1.80610 33.3 11.28
22 -49.161 1.07 12.59
23 305.611 3.85 1.43875 94.7 13.52
24 -12.634 0.15 14.15
25 * ANA 0.75 2.00 100 29.1 14.14
26 27.122 2.29 13.95
27 * CYL 1.18 1.80400 46.6 14.01
28 ∞ 1.30 1.80 400 46.6 14.62
29 * CYL 15.42 15.01
Image plane ∞

Aspheric surface 3rd surface
K = 0.00000e + 000 A 4 = -5.07333e-006 A 6 = -4.82533e-008 A 8 = -6.26578e-010 A10 = 2.40628e-013

Side 20
K = 0.00000e + 000 A 4 = -6.39729e-005 A 6 = -2.19476e-007 A 8 = 1.03158e-008 A10 = -1.36032e-010

Anamorphic surface data surface 9
Ry = 6.71518e + 001 Rz = 1.52064e + 002 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

16th page
Ry = 5.53025e + 001 Rz = 2.27955e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Side 25
Ry = 3.62715e + 001 Rz = 5.60441e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

27th cylindrical surface data
Ry = -2.85985e + 001 Ky = 0.00000e + 000 b2 = 0.00000e + 000 b4 = 0.00000e + 000
Rz = 0.00000e + 000 Kz = 0.00000e + 000 d2 = 0.00000e + 000 d4 = 0.00000e + 000


No. 29
Ry = 0.00000e + 000 Ky = 0.00000e + 000 b2 = 0.00000e + 000 b4 = 0.00000e + 000
Rz = -4.80410e + 001 Kz = 0.00000e + 000 d2 = 0.00000e + 000 d4 = 0.00000e + 000

Vertical direction Horizontal direction Oblique 45 ° focal length 7.44 5.57 6.59
F-number 4.00 2.84 3.43
Half angle of view 90 ° 90 ° 90 °
Half height 11.75 8.75 10.35
Total lens length 100.00 100.00 100.00
BF 15.42 15.42 15.42

[Numerical example 3]
Unit: mm

Surface data Surface number rd nd νd Effective diameter
1 22.368 1.01 2.00069 25.5 22.50
2 7.440 5.23 14.00
3 * 88.279 0.55 1.88300 40.8 13.16
4 12.948 3.35 11.80
5 * ANA 2.32 1.66565 35.6 10.35
6 -32.318 0.46 1.95375 32.3 9.66
7 11.873 1.82 8.96
8 -13.855 0.60 1.49700 81.5 8.95
9 -97.656 1.13 9.19
10 * ANA 1.90 1.85478 24.8 9.57
11 -19.338 0.57 9.57
12 ∞ 9.19 1.51633 64.1 9.03
13 ∞ 5.58 6.28
14 (aperture) ∞ 1.18 5.78
15 8.242 0.57 1.86501 42.0 6.04
16 6.103 1.78 1.55332 71.7 5.83
17 * ANA 1.45 5.71
18 ∞ 7.70 1.51633 64.1 5.38
19 ∞ 0.28 6.68
20 * 11.414 2.29 1.58313 59.4 7.00
21 -6.095 0.80 1.88300 40.8 7.02
22 42.134 0.10 7.53
23 10.769 2.31 1.43875 94.7 7.99
24 -13.767 0.15 8.14
25 29.747 0.60 1.85478 24.8 8.10
26 8.965 1.82 7.92
27 * ANA 1.27 1.55332 71.7 8.13
28 -10.667 9.00 8.70
Image plane ∞

Aspheric surface 3rd surface
K = 0.00000e + 000 A 4 = -3.87079e-005 A 6 = 1.19360e-006 A 8 = -5.13558e-008 A10 = 8.23504e-010 A12 = -5.50361e-012

Side 20
K = 0.00000e + 000 A 4 = -2.50009e-004 A 6 = 4.19879e-006 A 8 = -3.30062e-007 A10 = 8.71597e-009

Anamorphic surface data 5
Ry = 1.93881e + 001 Rz = 3.05440e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

10th page
Ry = 3.48218e + 001 Rz = 2.87789e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

17th
Ry = -1.24783e + 002 Rz = 1.03123e + 003 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Surface 27
Ry = -1.46567e + 001 Rz = -3.73717e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Various data
Vertical direction Horizontal direction Oblique 45 ° focal length 4.30 3.66 4.00
F-number 3.98 3.52 3.77
Half angle of view 90 ° 90 ° 90 °
Half image height 6.75 5.75 6.27
Total lens length 65.00 65.00 65.00
BF 9.00 9.00 9.00

[Numerical example 4]
Unit: mm

Surface data Surface number rd nd νd Effective diameter
1 22.133 1.01 2.00069 25.5 21.69
2 7.658 5.20 14.00
3 * -541.567 0.55 1.88300 40.8 12.92
4 12.447 3.35 11.53
5 * ANA 3.03 1.66565 35.6 10.21
6 -12.472 0.46 1.95375 32.3 9.52
7 14.268 2.21 8.96
8 -13.889 0.60 1.88 300 40.8 8.98
9 -35.493 0.20 9.35
10 * ANA 1.93 1.85478 24.8 9.61
11 -12.370 5.51 9.70
12 ∞ 11.07 6.91
13 (aperture) ∞ 0.34 6.47
14 9.958 0.57 1.88 300 40.8 6.60
15 6.570 2.01 1.55332 71.7 6.42
16 * ANA 5.00 6.37
17 ∞ 5.18 6.01
18 * 9.645 1.71 1.58313 59.4 8.05
19 -29.083 0.80 1.88300 40.8 8.02
20 9.637 0.07 7.90
21 8.520 2.59 1.43875 94.7 8.12
22 -13.699 0.14 8.26
23 50.144 0.60 1.85478 24.8 8.17
24 10.831 1.61 8.06
25 * ANA 1.27 1.55332 71.7 8.22
26 -10.667 9.00 8.75
Image plane ∞

Aspheric surface 3rd surface
K = 0.00000e + 000 A 4 = -2.23635e-005 A 6 = -2.64819e-006 A 8 = 1.14414e-007 A10 = -2.21145e-009 A12 = 1.60687e-011

18th page
K = 0.00000e + 000 A 4 = -3.29467e-004 A 6 = -3.46300e-007 A 8 = -1.21812e-007 A10 = 7.38789e-010

Anamorphic surface data 5
Ry = 1.80168e + 001 Rz = 2.79689e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

10th page
Ry = 9.68203e + 001 Rz = 6.42260e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000
-30.72407233039867 -36.35972406285578
16th page
Ry = -3.07241e + 001 Rz = -3.63597e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Side 25
Ry = -1.53830e + 001 Rz = -3.27992e + 001 Ky = 0.00000e + 000 Kz = 0.00000e + 000
c1 = 0.00000e + 000 c1p = 0.00000e + 000 c2 = 0.00000e + 000 c2p = 0.00000e + 000

Various data
Vertical direction Horizontal direction Oblique 45 ° focal length 4.30 3.66 3.99
F-number 3.98 3.66 3.91
Half angle of view 90 ° 90 ° 90 °
Half image height 6.75 5.75 6.27
Total lens length 66.01 66.01 66.01
BF 9.00 9.00 9.00

  Table 1 below shows various values in each example.

[Imaging device]
Next, an embodiment of the imaging apparatus of the present invention will be described. FIG. 11 is a schematic diagram of an imaging device (digital still camera) 200 of the present embodiment. The imaging device 200 includes a camera body 250 having one imaging element 260 and a lens device 210 including an optical system 220 similar to any one of the first to fourth embodiments. The lens device 210 and the camera body 250 may be configured integrally, or may be configured to be detachable. Note that FIG. 11 shows only one optical system because two optical systems are arranged side by side in the depth direction.

  The image circle formed by the two optical systems of the lens device 210 is designed so as to fit within the imaging area (area where pixels are arranged) of the imaging element 260.

  The imaging device 200 of the present embodiment includes the lens device 210, thereby enabling stereoscopic imaging with a wide angle of view and high image quality.

  The lens apparatus of each of the above-described embodiments is not limited to the digital still camera shown in FIG. 11, but can be applied to various image pickup apparatuses such as a broadcast camera, a silver halide film camera, and a surveillance camera.

  Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes can be made within the scope of the gist.

REFERENCE SIGNS LIST 100 Lens device 101, 102 Optical system AS Lens surfaces having different curvatures in two directions perpendicular to the optical axis

Claims (12)

It has two optical systems,
Each of the two optical systems has two lens surfaces having different curvatures in two directions perpendicular to the optical axis,
A lens device, wherein two images by the two optical systems can be formed on one image sensor.   The two directions are a first direction perpendicular to an axial ray incident on the most object side surface of each of the two optical systems, and a first direction perpendicular to the first direction and the axial ray. The lens device according to claim 1, wherein the second direction is a vertical direction. Each of the two optical systems is
3. The lens device according to claim 1, wherein the lens device has three or more lens surfaces having different curvatures in two directions perpendicular to the optical axis. Each of the two optical systems is
Has an aperture,
The lens according to claim 1, further comprising a lens surface having different curvatures in at least one surface on each of a light incident side and a light emission side of the stop in two directions perpendicular to the optical axis. 5. Lens device. Each of the two optical systems is
The lens device according to any one of claims 1 to 4, further comprising at least two reflecting members for bending an optical path.   The lens device according to claim 5, wherein the reflection member is disposed between two lens surfaces having different curvatures in two directions perpendicular to the optical axis. Each of the two optical systems is
When all angles of view are AV,
150 ° <AV <190 °
The lens device according to any one of claims 1 to 6, wherein the following conditional expression is satisfied.   The lens device according to any one of claims 1 to 7, wherein the lens surfaces having different curvatures in two directions perpendicular to the optical axis include an anamorphic surface.   The lens device according to any one of claims 1 to 8, wherein the lens surfaces having different curvatures in two directions perpendicular to the optical axis include a cylindrical surface. Each of the two optical systems is
The focal length in a first direction perpendicular to the axial rays incident on the most object-side surface of each of the two optical systems is fv, and both are perpendicular to the first direction and the axial rays. When the focal length in the second direction is fh,
0.55 <fh / fv <0.90
The lens device according to claim 1, wherein the following conditional expression is satisfied.   An imaging apparatus comprising: the lens device according to claim 1; and an imaging element configured to capture an optical image formed by the two optical systems.   The image pickup apparatus according to claim 11, wherein the image circles of the two optical systems fall within an image pickup area of the image pickup device.

Images