JPWO2018189818A1 - Lens system, imaging device, moving body and system - Google Patents

Abstract

The lens system includes, in order from the object side, a first lens group, an aperture stop, and a second lens group having positive refractive power. The first lens group may include, in order from the object side, a first-a lens group having negative refractive power, a reflecting member for bending an optical path, and a first-b lens group having positive refractive power. The first lens subunit, in order from the object side, is a negative first meniscus lens with its convex surface facing the object side, a second negative lens with its concave surface facing the image side, and a third negative lens. May be included. The first b lens group may include at least one positive lens. The second lens group may include four or more lenses including at least one cemented lens. The conditional expression −1.8 <f11 / f <−1.25 may be satisfied, where f is the focal length of the entire system and f11 is the focal length of the lens subunit aa.

Description

  The present invention relates to a lens system, an imaging device, a moving body, and a system.

A wide-angle lens having a two-group configuration is known.
Patent Document 1 Japanese Patent Application Publication No. 2012-18422 Patent Document 2 Japanese Patent Application Publication No. 2015-22142 Patent Document 3 Japanese Patent Application Publication No. 2015-43108

Problem to be solved

  There is a demand for a lens system having high resolution, a small size and a wide half angle of view.

General disclosure

The lens system according to an aspect of the present invention includes, in order from the object side, a first lens group, an aperture stop, and a second lens group having positive refractive power. The first lens group may include, in order from the object side, a first-a lens group having negative refractive power, a reflecting member for bending an optical path, and a first-b lens group having positive refractive power. The first lens subunit, in order from the object side, is a negative first meniscus lens with its convex surface facing the object side, a second negative lens with its concave surface facing the image side, and a third negative lens. May be included. The first b lens group may include at least one positive lens. The second lens group may include four or more lenses including at least one cemented lens. Assuming that the focal length of the entire system is f, and the focal length of the lens group 1a is f11, the conditional expression -1.8 <f11 / f <-1.25
Good to be satisfied.

Assuming that the refractive index of the first negative lens and the second negative lens for the d-line of the ith negative lens is Ni, and the Abbe number for the d-line of the ith lens is vi, the conditional expression N1> 1.8
N2> 1.7
v1> 30
v2> 30
(I is a natural number)
Good to be satisfied.

Assuming that the focal length of the second lens group is f2, the conditional expression 3.6 <f2 / f <5.6
Good to be satisfied.

Assuming that the radius of curvature of the image side surface of the first negative lens is R12 and the focal length of the first negative lens is f_1, the conditional expression 0.45 <R12 / | f_1 | <0.7
Good to be satisfied.

Assuming that the refractive index for the d-line of the reflecting member is Npr, the conditional expression Npr> 1.8
Good to be satisfied.

  At least one of the second negative lens and the third negative lens may have an aspheric shape.

  An imaging device according to an aspect of the present invention includes the above-described lens system and an imaging element.

  The moving body according to an aspect of the present invention moves with the lens system described above.

  The mobile may be an unmanned aerial vehicle.

  A system according to an aspect of the present invention includes the above lens system and a support mechanism that displaceably supports the lens system.

  According to the above lens system, a compact lens system having high resolution and a wide half angle of view is desired.

  The above summary of the invention does not enumerate all of the features of the present invention. A subcombination of these feature groups can also be an invention.

An example of a mobile system 10 comprising an unmanned aerial vehicle (UAV) 100 and a controller 50 is schematically illustrated. An example of a functional block of UAV100 is shown. The lens configuration of the lens system 300 in the first embodiment is shown together with the filter F and the image sensor 221. The spherical aberration and astigmatism of the lens system 300 are shown. The lens structure of the lens system 400 in 2nd Example is shown with the filter F and the image pick-up element 221. FIG. The spherical aberration and astigmatism of the lens system 400 are shown. The lens structure of the lens system 500 in 3rd Example is shown with the filter F and the image pick-up element 221. FIG. The spherical aberration and astigmatism of the lens system 500 are shown. The lens configuration of the lens system 600 in the fourth embodiment is shown together with the filter F and the image sensor 221. The spherical aberration and astigmatism of the lens system 600 are shown. FIG. 18 is an external perspective view showing an example of a stabilizer 3000.

  Hereinafter, the present invention will be described through the embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Further, not all combinations of features described in the embodiments are essential to the solution of the invention. It will be apparent to those skilled in the art that various changes or modifications can be added to the following embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the present invention.

  The claims, the description, the drawings, and the abstract contain matters which are subject to copyright protection. The copyright holder will not object to any copy of these documents as they appear in the Patent Office file or record. However, in all other cases, all copyrights are reserved.

  FIG. 1 schematically illustrates an example of a mobile system 10 comprising an unmanned aerial vehicle (UAV) 100 and a controller 50. The UAV 100 includes a UAV body 101, a gimbal 110, a plurality of imaging devices 230, and an imaging device 220. The imaging device 220 includes a lens device 160 and an imaging unit 140. The UAV 100 is an example of a moving body that moves with an imaging device. The moving body is a concept including UAVs, other aircraft moving in the air, vehicles moving on the ground, ships moving on the water, and the like.

  The UAV body 101 comprises a plurality of rotors. The UAV body 101 causes the UAV 100 to fly by controlling the rotation of a plurality of rotors. The UAV body 101 causes the UAV 100 to fly using, for example, four rotors. The number of rotors is not limited to four. The UAV 100 may be a fixed wing aircraft that does not have rotors.

  The imaging device 230 is a camera for imaging which captures an object included in a desired imaging range. The plurality of imaging devices 230 are sensing cameras that capture the periphery of the UAV 100 to control the flight of the UAV 100. The imaging device 230 may be fixed to the UAV main body 101.

  Two imaging devices 230 may be provided at the front, which is the nose of the UAV 100. Two further imaging devices 230 may be provided on the bottom of the UAV 100. The two front imaging devices 230 may be paired to function as a so-called stereo camera. The two imaging devices 230 on the bottom side may also be paired and function as a stereo camera. Three-dimensional spatial data around the UAV 100 may be generated based on the images captured by the plurality of imaging devices 230. The distances to the subject imaged by the plurality of imaging devices 230 may be specified by a stereo camera by the plurality of imaging devices 230.

  The number of imaging devices 230 included in the UAV 100 is not limited to four. The UAV 100 may include at least one imaging device 230. UAV 100 may include at least one imaging device 230 on each of the nose, aft, sides, bottom, and ceiling of UAV 100. The imaging device 230 may have a single focus lens or a fisheye lens. In the description related to the UAV 100, the plurality of imaging devices 230 may be simply referred to simply as the imaging devices 230.

  The controller 50 includes a display unit 54 and an operation unit 52. The operation unit 52 receives an input operation for controlling the attitude of the UAV 100 from the user. The controller 50 transmits a signal for controlling the UAV 100 based on the user's operation received by the operation unit 52. For example, the operation unit 52 receives an operation for specifying the focus position of the lens device 160. The controller 50 transmits a signal instructing change of the focus position to the UAV 100.

  The controller 50 receives an image captured by at least one of the imaging device 230 and the imaging device 220. The display unit 54 displays the image received by the controller 50. The display unit 54 may be a touch panel. The controller 50 may receive an input operation from the user through the display unit 54. The display unit 54 may receive a user operation or the like in which the user designates the position of the subject to be imaged by the imaging device 220.

  The imaging unit 140 generates and records image data of an optical image formed by the lens device 160. The lens device 160 may be provided integrally with the imaging unit 140. The lens device 160 may be a so-called interchangeable lens. The lens device 160 may be detachably provided to the imaging unit 140.

  The gimbal 110 has a support mechanism that movably supports the imaging device 220. The imaging device 220 is attached to the UAV body 101 via the gimbal 110. The gimbal 110 supports the imaging device 220 rotatably about the pitch axis. The gimbal 110 supports the imaging device 220 rotatably about a roll axis. The gimbal 110 supports the imaging device 220 rotatably around the yaw axis. The gimbal 110 may rotatably support the imaging device 220 about at least one of a pitch axis, a roll axis, and a yaw axis. The gimbal 110 may rotatably support the imaging device 220 about each of the pitch axis, the roll axis, and the yaw axis. The gimbal 110 may hold the imaging unit 140. The gimbal 110 may hold the lens assembly 160. The gimbal 110 may change the imaging direction of the imaging device 220 by rotating the imaging unit 140 and the lens device 160 around at least one of a yaw axis, a pitch axis, and a roll axis.

  FIG. 2 shows an example of a functional block of the UAV 100. The UAV 100 includes an interface 102, a control unit 104, a memory 106, a gimbal 110, an imaging unit 140, and a lens device 160.

  Interface 102 communicates with controller 50. The interface 102 receives various instructions from the controller 50. The control unit 104 controls the flight of the UAV 100 in accordance with the command received from the controller 50. The control unit 104 controls the gimbal 110, the imaging unit 140, and the lens device 160. The control unit 104 may be configured by a microprocessor such as a CPU or an MPU or a microcontroller such as an MCU. The memory 106 stores programs required for the control unit 104 to control the gimbal 110, the imaging unit 140, and the lens device 160.

  The memory 106 may be a computer readable recording medium. The memory 106 may include at least one of flash memory such as SRAM, DRAM, EPROM, EEPROM, and USB memory. The memory 106 may be provided in the housing of the UAV 100. It may be provided to be removable from the housing of the UAV 100.

  The gimbal 110 includes a control unit 112, a driver 114, a driver 116, a driver 118, a drive unit 124, a drive unit 126, a drive unit 128, and a support mechanism 130. The drive unit 124, the drive unit 126, and the drive unit 128 may be motors.

  The support mechanism 130 supports the imaging device 220. The support mechanism 130 movably supports the imaging direction of the imaging device 220. The support mechanism 130 rotatably supports the imaging unit 140 and the lens device 160 about the yaw axis, the pitch axis, and the roll axis. The support mechanism 130 includes a rotation mechanism 134, a rotation mechanism 136, and a rotation mechanism 138. The rotation mechanism 134 rotates the imaging unit 140 and the lens device 160 about the yaw axis using the drive unit 124. The rotation mechanism 136 uses the drive unit 126 to rotate the imaging unit 140 and the lens device 160 about the pitch axis. The rotation mechanism 138 uses the drive unit 128 to rotate the imaging unit 140 and the lens device 160 about the roll axis.

  In response to the operation command of the gimbal 110 from the control unit 104, the control unit 112 outputs operation commands indicating the respective rotation angles to the driver 114, the driver 116, and the driver 118. The driver 114, the driver 116, and the driver 118 drive the drive unit 124, the drive unit 126, and the drive unit 128 in accordance with the operation instruction indicating the rotation angle. The rotation mechanism 134, the rotation mechanism 136, and the rotation mechanism 138 are respectively driven and rotated by the drive unit 124, the drive unit 126, and the drive unit 128, and change the postures of the imaging unit 140 and the lens device 160.

  The imaging unit 140 captures an image by the light passing through the lens system 300. The imaging unit 140 includes a control unit 222, an imaging element 221, and a memory 223. The control unit 222 may be configured by a microprocessor such as a CPU or an MPU or a microcontroller such as an MCU. The control unit 222 controls the imaging unit 140 and the lens device 160 in accordance with operation commands for the imaging unit 140 and the lens device 160 from the control unit 104. The control unit 222 outputs, to the lens device 160, a control command instructing the lens device 160 to move the focus position based on the signal received from the controller 50.

  The memory 223 may be a computer readable recording medium, and may include at least one of SRAM, DRAM, EPROM, EEPROM, and flash memory such as USB memory. The memory 223 may be provided inside the housing of the imaging unit 140. It may be provided to be removable from the housing of the imaging unit 140.

  The imaging element 221 is held inside the housing of the imaging unit 140, generates image data of an optical image formed through the lens device 160, and outputs the image data to the control unit 222. The control unit 222 stores the image data output from the imaging device 221 in the memory 223. The control unit 222 may output image data to the memory 106 via the control unit 104 and store the image data.

  The lens device 160 is a single focus lens. The lens arrangement 160 may be a full length fixed lens. The lens device 160 includes a control unit 162, a memory 163, a drive mechanism 161, and a lens system 300. The lens system 300 includes a first lens group 301, an aperture stop S, and a second lens group 302 in order from the object side to the image side. In the description of the present embodiment, the optical axis of the lens system 300 may be simply referred to as the “optical axis”. In the lens system 300, the first lens group 301 has an optical member that bends incident light. Thereby, the lens system 300 can be miniaturized. The "lens group" refers to a group of one or more lenses. The lens composed of a single lens is also called "lens group".

  The control unit 162 performs focusing according to a control command from the control unit 222 by displacing the focus lens provided in the lens system 300 along the optical axis. The image formed by the lens system 300 of the lens device 160 is captured by the imaging unit 140.

  The drive mechanism 161 displaces the focus lens provided in the lens system 300. The drive mechanism 161 includes, for example, an actuator and a holding member that holds the focus lens. Driving pulses are supplied from the control unit 162 to the actuator. The actuator is displaced by a drive amount corresponding to the supplied pulse. The focus lens is displaced by displacing the holding member in accordance with the displacement of the actuator. Thereby, focusing is performed. In the imaging device 220, magnified photography is performed by so-called electronic zoom. For example, the magnified image capturing is performed by cutting out a part of the image captured by the imaging element 221.

  The lens device 160 may be provided integrally with the imaging unit 140. The lens device 160 may be a so-called interchangeable lens. The lens device 160 may be detachably provided to the imaging unit 140.

  The imaging device 230 includes a control unit 232, a control unit 234, an imaging element 231, a memory 233, and a lens 235. The control unit 232 may be configured by a microprocessor such as a CPU or an MPU or a microcontroller such as an MCU. The control unit 232 controls the imaging device 231 in accordance with an operation command of the imaging device 231 from the control unit 104.

  The control unit 234 may be configured by a microprocessor such as a CPU or an MPU or a microcontroller such as an MCU. The control unit 234 may control the focus of the lens 235 in response to an operation command for the lens 235. The control unit 234 may control the aperture stop of the lens 235 in accordance with the operation command to the lens 235.

  The memory 233 may be a computer readable recording medium. The memory 233 may include at least one of flash memory such as SRAM, DRAM, EPROM, EEPROM, and USB memory.

  The imaging element 231 generates image data of an optical image formed through the lens 235 and outputs the image data to the control unit 232. The control unit 232 stores the image data output from the imaging device 231 in the memory 233.

  In the present embodiment, an example in which the UAV 100 includes the control unit 104, the control unit 112, the control unit 222, the control unit 232, the control unit 234, and the control unit 162 will be described. However, any one control unit may execute the processing performed by a plurality of the control unit 104, the control unit 112, the control unit 222, the control unit 232, the control unit 234, and the control unit 162. The processing performed by the control unit 104, the control unit 112, the control unit 222, the control unit 232, the control unit 234, and the control unit 162 may be performed by one control unit. In the present embodiment, an example in which the UAV 100 includes the memory 106, the memory 223, and the memory 233 will be described. Information stored in at least one of memory 106, memory 223, and memory 233 may be stored in memory 106, memory 223, and one or more other memories of memory 233.

  FIG. 3 shows the lens configuration of the lens system 300 in the first embodiment, together with the filter F and the image sensor 221. The lens system 300 includes, in order from the object side, a first lens group 301, an aperture stop S, and a second lens group 302 having positive refractive power. An optical filter F is provided on the object side of the imaging element 221. The light passing through the lens system 300 and the filter F is incident on the imaging element 221.

  The lens system 300 has a two-group configuration. In the description of each embodiment, "Ln" indicates a lens. Here, n following L is an integer of 1 or more. n indicates that it is the n-th lens from the object side. In each embodiment, Ln is a symbol assigned to indicate that it is the nth lens from the object side. It does not mean that the lens assigned the symbol Ln in the description of each embodiment and the lens in the other embodiments assigned the same symbol Ln are the same lens.

  The first lens group 301 has positive refractive power. The first lens group 301 includes, in order from the object side, a first a lens group 311, a reflecting member Pr, and a first b lens group 312. The first sub lens group 311 has negative refractive power. The first b lens group 312 has positive refractive power. The reflecting member Pr bends the light path. The reflecting member Pr reflects the light incident from the side of the lens group 311a and emits the light to the side of the lens group 312b.

  The first sub lens group 311 includes, in order from the object side, three negative single lenses: a first negative lens L1, a second negative lens L2, and a third negative lens L3. The first negative lens L1 has a meniscus shape with a convex surface facing the object side. The second negative lens L2 has a concave surface on the image side. The third negative lens L3 has a concave surface on the image side. The first b lens group 312 includes at least one positive lens.

  The second lens group 302 includes four or more lenses including at least one cemented lens. In the first embodiment, the second lens group 302 includes five lenses including one cemented lens.

The conditional expression 1 is satisfied by setting the focal length of the entire lens system as f and the focal length of the lens group 1a as f11.
−1.8 <f11 / f <−1.25 (Conditional expression 1)

  Each of the first negative lens L1, the second negative lens L2, and the third negative lens L3 included in the first a lens group 311 is a single lens. The negative refractive power of the first lens group 311 can be increased by forming the first lens group 311 with three negative single lenses. Therefore, the lens system 300 can be miniaturized. Further, by sharing the negative refracting power among three, the occurrence of off-axis aberration can be suppressed.

  In addition, axial chromatic aberration and lateral chromatic aberration can be achieved by the first b lens group 312 including at least one positive lens and the second lens group 302 including four or more lenses including at least one cemented lens. Can be corrected.

  If the upper limit of conditional expression 1 is exceeded, the refractive power of the 1-a lens group 311 becomes strong, and correction of off-axis aberrations becomes difficult. When the value goes below the lower limit of conditional expression 1, the refractive power becomes weak and the lens system 300 becomes large. By satisfying conditional expression 1, miniaturization and high resolution can be realized. According to the lens system 300, it is possible to provide a small-sized lens system having a wide half angle of view, which has high resolving power.

For the first negative lens L1 and the second negative lens L2 included in the first a lens group 311, let i be a natural number of 1 or 2, and the refractive index for the d-line of the i th negative lens is Ni. It is preferable that conditional expression 2 to conditional expression 5 be satisfied, where the Abbe number for the d-line is vi.
N1> 1.8 (Conditional expression 2)
N2> 1.7 (Conditional expression 3)
v1> 30 (conditional expression 4)
v2> 30 (conditional expression 5)
Satisfying conditional expressions 2 to 5 can realize downsizing and good correction of chromatic aberration. When N1 falls below the lower limit of conditional expression 1 or N2 falls below the lower limit of conditional expression 2, the negative refractive power of the first negative lens L1 or the second negative lens L2 is reduced to realize miniaturization. You need to be strong. If the radius of curvature of the lens is reduced in order to intensify the negative refractive power, off-axis aberrations increase and aberration correction becomes difficult. In addition, when v1 falls below the lower limit of conditional expression 4 or v5 falls below the lower limit of conditional expression 5, lateral chromatic aberration becomes large, and it becomes difficult to correct the chromatic aberration with the lens in the subsequent stage.

Assuming that the focal length of the second lens group 302 is f2, it is preferable that conditional expression 6 be satisfied.
3.6 <f2 / f <5.6 (conditional expression 6)

  As the upper limit of conditional expression 6 is exceeded, the refractive power of the second lens group becomes weaker. Therefore, it is necessary to make the second lens group 302 larger, which leads to an increase in the size of the lens system 300. Below the lower limit of conditional expression 6, the refractive power of the second lens group 302 becomes too strong, making aberration correction difficult. By satisfying conditional expression 6, downsizing of the lens system 300 and ease of aberration correction can be realized in a well-balanced manner.

It is preferable to satisfy conditional expression 7 with the radius of curvature of the image side surface of the first negative lens L1 included in the 1a-th lens group 311 as R12 and the focal length of the first negative lens as f_1.
0.45 <R12 / | f_1 | <0.70 (Conditional expression 7)

  The conditional expression 7 defines the refractive power of the image side surface of the first negative lens L1. If the upper limit of conditional expression 7 is exceeded, the refractive power of the image side surface of the first negative lens L1 becomes too weak, and the lens system 300 becomes large. Below the lower limit of Conditional Expression 7, the refractive power of the image side surface of the first negative lens L1 becomes too strong, and the off-axis aberration becomes large. In addition, since the lens shape of the first negative lens L1 approaches a hemisphere, it becomes difficult to manufacture the first negative lens L1.

Assuming that the refractive index for the d-line of the reflecting member Pr is Npr, it is preferable that conditional expression 8 be satisfied.
Npr> 1.8 (Conditional expression 8)

  Conditional Expression 8 defines the refractive index at the d-line of the reflecting member Pr. Below the lower limit of conditional expression 8, enlargement of the first lens group 301 is caused, and miniaturization of the lens system 300 becomes difficult. By satisfying the conditional expression, the light path can be shortened.

  It is preferable that at least one of the second negative lens L2 and the third negative lens L3 included in the first a lens group 311 has an aspheric shape. In the lens system 300, the third negative lens L3 has an aspheric shape.

  Of the lenses included in the lens system 300, the heights of the on-axis ray and the off-axis ray of the three first negative lenses L1, the second negative lens L2, and the third negative lens L3 located on the object side The difference gets bigger. Making at least one of the two negative lenses L2 and L3 located on the image side among the first negative lens L1, the second negative lens L2 and the third negative lens L3 into an aspheric surface Thus, off-axis aberrations such as astigmatism and coma can be corrected effectively. Further, the cost can be reduced as compared with the case where the first lens on the object side, which has the largest effective diameter, is made aspheric.

  According to the above configuration of the lens system 300, it is possible to provide a small-sized lens system having a wide half angle of view, which has high resolving power. For example, a lens system having a half angle of view of 90 degrees or more can be provided. The UAV 100 may include two or more imaging devices having the same configuration as the imaging device 220 including the lens system 300, and may use two or more imaging devices as the omnidirectional camera.

  In the lens system 300 of the first embodiment, the third negative lens L3 is a biconcave lens having an aspheric shape on both sides. The reflecting member Pr is a prism that bends the light path by 90 °. An optical member other than a prism may be applied as a reflecting member.

  The second lens group 302 includes a cemented lens of a biconvex lens L4 and a biconcave lens L5, a cemented lens of a biconvex lens L8 and a biconcave lens L9, and a biconvex lens L10 having aspheric surfaces on both sides.

  Each lens is constituted by a glass lens. The linear expansion coefficient can be reduced by about one digit as compared with the case of using a plastic lens. Therefore, it is possible to suppress a change in optical characteristics when the temperature changes.

  Next, lens data and the like in each embodiment of the lens system will be described. Here, the meanings of symbols and the like used in the description of each embodiment of the lens system will be described. The plurality of surfaces of the lens system are identified by surface number i, where i is a natural number. The first surface of the lens viewed from the object side is taken as the first surface, and thereafter, the surface number is counted up in the order in which the light beam passes through the surface. “STO” in the plane number represents the aperture plane of the aperture stop S. “Di” indicates the distance on the optical axis between the i-th surface and the (i + 1) -th surface.

  "F" indicates the focal length. "Fno" indicates an F number. "R" shows a radius of curvature. In the radius of curvature, "INF" indicates that it is a plane. "N" shows a refractive index. "V" indicates the Abbe number. The refractive index n and the Abbe number v are values at the d-line (λ = 587.56 nm).

Table 1 shows lens data of lenses of the lens system 300. In Table 1, Di, n and v are shown in association with the surface number i.

In Table 1, the surface with * attached to the surface number is a surface having an aspherical shape. Table 2 shows the surface number of the surface having the aspheric shape and the aspheric parameters. In Table 2, "κ" indicates a conic constant (conic constant). “A”, “B”, “C”, and “D” are fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients, respectively. Also, assuming that i is an integer, “E−i” indicates an exponential expression with a base of 10 in the aspheric coefficients. In other words, "E-i" represents a ^{"10 -i".} For example, “−1.93744E-03” represents “−1.93744 × 10 ⁻³ ”.

If “x” is the distance in the optical axis direction from the vertex of the lens surface, “y” is the height in the direction perpendicular to the optical axis, and “c” is the paraxial curvature at the vertex of the lens, the aspheric shape is It is defined by the following formula:
x = cy ² / (1 + (1-(1 +)) c ² y ² ) ^1/2 ) + Ay ⁴ + By ⁶ + Cy ⁸ + Dy ¹⁰
In addition, "x" is also called sag amount. "Y" is also called image height. The paraxial curvature is the reciprocal of the radius of curvature.

Table 3 shows the focal length, the f-number, and the half angle of view of the lens system 300.

  FIG. 4 shows the spherical aberration and the astigmatism of the lens system 300. In spherical aberration, the solid line indicates the d-line (587.56 nm), the broken line indicates the g-line (435.84 nm), and the dashed-dotted line indicates the c-line (656.27 nm). In astigmatism, a solid line indicates a d-line sagittal image plane, and a broken line indicates a d-line meridional image plane. It is clear from the aberration diagrams that the lens system 300 in the first example has various aberrations corrected well and has excellent imaging performance.

  FIG. 5 shows the lens configuration of the lens system 400 in the second embodiment, along with the filter F and the image sensor 221. The lens system 400 includes, in order from the object side, a first lens group 401, an aperture stop S, and a second lens group 402. An optical filter F is provided on the object side of the imaging element 221. The first lens group 401 and the second lens group 402 correspond to the first lens group 301 and the second lens group 302 in the lens system 300, respectively.

  In the lens system 400 of the second embodiment, the first lens group 401 has a positive refractive power. The first lens group 401 includes, in order from the object side, a first a lens group 411, a reflecting member Pr, and a first b lens group 412. The first sub lens group 411 includes a negative meniscus lens L1 having a convex surface on the object side, a negative meniscus lens L2 having a convex surface on the object side, and a biconcave lens L3 having aspheric surfaces on both surfaces. The first b lens group 412 includes a cemented lens of a biconvex lens L4 and a biconcave lens L5.

  The reflecting member Pr is a prism that bends the light path by 90 °, and has a configuration similar to that of the reflecting member Pr in the lens system 300. An optical member other than a prism may be applied as a reflecting member. In FIG. 5, for the purpose of aligning and clearly showing the directions of the lenses included in the lens system 400, the reflecting member Pr is abbreviated as a square, and the optical axes before and after the reflecting member Pr are the same in the drawing. It is shown in line with. The lens configuration of each of the following embodiments is similarly described.

  The second lens group 402 includes a positive lens L6 having an aspheric surface on both sides, a cemented lens of a biconvex lens L7 and a biconcave lens L8, and a positive lens L9 having an aspheric shape on both surfaces.

  Each lens is constituted by a glass lens. By using a glass lens, the linear expansion coefficient can be reduced by about one digit as compared with the case of using a plastic lens. Therefore, it is possible to suppress a change in optical characteristics when the temperature changes.

Table 4 shows lens data of lenses of the lens system 400. In Table 4, Di, n and v are shown in association with the surface number i.

In Table 4, the surface with * attached to the surface number is a surface having an aspherical shape. Table 5 shows the surface number of the surface having an aspheric shape and the aspheric parameters. In Table 5, “κ” indicates a conic constant (conic constant). “A”, “B”, “C”, and “D” are fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients, respectively. Also, assuming that i is an integer, “E−i” indicates an exponential expression with a base of 10 in the aspheric coefficients. In other words, "E-i" represents a ^{"10 -i".} For example, "-8.53826E-04" represents "-8.53826 ^10-4 ".

Table 6 shows the focal length, the f-number, and the half angle of view of the lens system 400.

  FIG. 6 shows spherical aberration and astigmatism of the lens system 400. In spherical aberration, the solid line indicates the d-line (587.56 nm), the broken line indicates the g-line (435.84 nm), and the dashed-dotted line indicates the c-line (656.27 nm). In astigmatism, a solid line indicates a d-line sagittal image plane, and a broken line indicates a d-line meridional image plane. It is clear from the respective aberration diagrams that the lens system 400 is well corrected for various aberrations and has excellent imaging performance.

  FIG. 7 shows the lens configuration of the lens system 500 in the third embodiment, together with the filter F and the image sensor 221. The lens system 500 includes, in order from the object side, a first lens group 501, an aperture stop S, and a second lens group 502. An optical filter F is provided on the object side of the imaging element 221. The first lens group 501 and the second lens group 502 correspond to the first lens group 301 and the second lens group 302 in the lens system 300, respectively.

  In the lens system 500 of the third embodiment, the first lens group 501 has a positive refractive power. The first lens group 501 includes, in order from the object side, a first a lens group 511, a reflecting member Pr, and a first b lens group 512. The first sub lens group 511 includes a negative meniscus lens L1 having a convex surface on the object side, a negative meniscus lens L2 having a convex surface on the object side, and a biconcave lens L3 having an aspheric surface on both surfaces. The first b lens group 512 includes a cemented lens of a biconvex lens L4 and a negative meniscus lens L5. The reflecting member Pr is a prism that bends the light path by 90 °. An optical member other than a prism may be applied as a reflecting member. The second lens group 502 includes a positive lens L6 having an aspheric surface on both sides, a cemented lens of a biconvex lens L7 and a biconcave lens L8, and a biconvex lens L9 having an aspheric shape on both surfaces.

  Each lens is constituted by a glass lens. By using a glass lens, the linear expansion coefficient can be reduced by about one digit as compared with the case of using a plastic lens. Therefore, it is possible to suppress a change in optical characteristics when the temperature changes.

Table 7 shows lens data of lenses of the lens system 500. In Table 7, Di, n and v are shown in association with the surface number i.

In Table 7, the surface with * attached to the surface number is a surface having an aspherical shape. Table 8 shows the surface number of the surface having an aspheric shape, and the aspheric parameters. In Table 8, “κ” indicates a conic constant (conic constant). “A”, “B”, “C”, and “D” are fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients, respectively. Also, assuming that i is an integer, “E−i” indicates an exponential expression with a base of 10 in the aspheric coefficients. In other words, "E-i" represents a ^{"10 -i".} For example, “−6.39797E-04” represents “−6.39797 × 10 ⁻⁴ ”.

Table 9 shows the focal length, the f-number, and the half angle of view of the lens system 500.

  FIG. 8 shows the spherical aberration and the astigmatism of the lens system 500. In spherical aberration, the solid line indicates the d-line (587.56 nm), the broken line indicates the g-line (435.84 nm), and the dashed-dotted line indicates the c-line (656.27 nm). In astigmatism, a solid line indicates a d-line sagittal image plane, and a broken line indicates a d-line meridional image plane. From each aberration diagram, it is clear that the lens system 500 has various aberrations well corrected and has excellent imaging performance.

  FIG. 9 shows the lens configuration of the lens system 600 in the fourth embodiment, together with the filter F and the image sensor 221. The lens system 600 includes a first lens group 601, an aperture stop S, and a second lens group 602 in order from the object side. An optical filter F is provided on the object side of the imaging element 221. The first lens group 601 and the second lens group 602 correspond to the first lens group 301 and the second lens group 302 in the lens system 300, respectively.

  The first lens group 601 has positive refractive power. The first lens group 601 includes, in order from the object side, a first a lens group 611, a reflecting member Pr, and a first b lens group 612. The first sub lens group 611 includes a negative meniscus lens L1 having a convex surface on the object side, a negative meniscus lens L2 having a convex surface on the object side, and a negative lens L3. The first b lens group 612 includes a cemented lens of a biconvex lens L4 and a biconcave lens L5. The reflecting member Pr is a prism that bends the light path by 90 °. An optical member other than a prism may be applied as a reflecting member. The second lens group 602 includes a positive lens L6 having an aspheric surface on both sides, a cemented lens of a biconvex lens L7 and a biconcave lens L8, and a biconvex lens L9 having an aspheric shape on both surfaces.

  Each lens is constituted by a glass lens. By using a glass lens, the linear expansion coefficient can be reduced by about one digit as compared with the case of using a plastic lens. Therefore, it is possible to suppress a change in optical characteristics when the temperature changes.

Table 10 shows lens data of lenses of the lens system 600. In Table 10, Di, n and v are shown in association with the surface number i.

In Table 10, the surface with * attached to the surface number is a surface having an aspherical shape. Table 11 shows the surface number of the surface having an aspheric shape, and the aspheric parameters. In Table 11, “κ” indicates a conic constant (conic constant). “A”, “B”, “C”, and “D” are fourth-order, sixth-order, eighth-order, and tenth-order aspheric coefficients, respectively. Also, assuming that i is an integer, “E−i” indicates an exponential expression with a base of 10 in the aspheric coefficients. In other words, "E-i" represents a ^{"10 -i".} For example, “2.89955E-04” represents “2.89955 × 10 ⁻⁴ ”.

Table 12 shows the focal length, the f-number, and the half angle of view of the lens system 600.

  FIG. 10 shows spherical aberration and astigmatism of the lens system 600. In spherical aberration, the solid line indicates the d-line (587.56 nm), the broken line indicates the g-line (435.84 nm), and the dashed-dotted line indicates the c-line (656.27 nm). In astigmatism, a solid line indicates a d-line sagittal image plane, and a broken line indicates a d-line meridional image plane. It is clear from the respective aberration diagrams that the lens system 600 is well corrected for various aberrations and has excellent imaging performance.

Table 13 shows the numerical values according to the conditional expressions in the first to sixth examples.

Table 14 shows the focal lengths according to the conditional expression 1, the conditional expression 6 and the conditional expression 7 in the first embodiment to the sixth embodiment.

  According to the lens system described above, it is possible to provide a compact lens system having a high resolution and a wide half angle of view.

  FIG. 11 is an external perspective view showing an example of the stabilizer 3000. The stabilizer 3000 is another example of a moving body. For example, the camera unit 3013 included in the stabilizer 3000 may include an imaging device having a configuration similar to that of the imaging device 220. The camera unit 3013 may include a lens device having the same configuration as the lens device 160.

  The stabilizer 3000 includes a camera unit 3013, a gimbal 3020, and a handle 3003. The gimbal 3020 rotatably supports the camera unit 3013. The gimbal 3020 has a pan axis 3009, a roll axis 3010, and a tilt axis 3011. The gimbal 3020 rotatably supports the camera unit 3013 about the pan axis 3009, the roll axis 3010, and the tilt axis 3011. The gimbal 3020 is an example of a support mechanism.

  The camera unit 3013 is an example of an imaging device. The camera unit 3013 has a slot 3014 for inserting a memory. The gimbal 3020 is fixed to the handle 3003 via the holder 3007.

  The handle portion 3003 has a gimbal 3020 and various buttons for operating the camera unit 3013. The handle portion 3003 includes a shutter button 3004, a recording button 3005, and an operation button 3006. By pressing the shutter button 3004, a still image can be recorded by the camera unit 3013. By pressing the recording button 3005, a moving image can be recorded by the camera unit 3013.

  The device holder 3001 is fixed to the handle 3003. The device holder 3001 holds a mobile device 3002 such as a smartphone. The mobile device 3002 is communicably connected to the stabilizer 3000 via a wireless network such as WiFi. Thus, the image captured by the camera unit 3013 can be displayed on the screen of the mobile device 3002.

  Also in the stabilizer 3000, when the camera unit 3013 includes the lens system having the same configuration as that of the lens system included in the lens device 160, it is possible to obtain an image with high resolution at a wide angle of view. In addition, the camera unit 3013 can be miniaturized.

  As described above, the UAV 100 and the stabilizer 3000 have been described as an example of the moving object. An imaging device having the same configuration as the imaging device 220 may be attached to a mobile other than the UAV 100 and the stabilizer 3000.

  In the above, the imaging device attached to a mobile body was demonstrated. However, the imaging device having the same configuration as the imaging device 220 is not limited to the imaging device attached to the moving body. The same configuration as the imaging device 220 can be applied to a non-lens interchangeable camera such as a so-called compact digital camera. The same configuration as the lens device 160 can be applied to the interchangeable lens of a lens interchangeable type camera such as a single-lens reflex camera. The same configuration as the lens device 160 can be applied to a video camera or the like. The same configuration as the lens device 160 can be applied to the configuration of various lens devices for imaging.

  The order of execution of each process such as operations, procedures, steps, and steps in the apparatuses, systems, programs, and methods shown in the claims, the specification, and the drawings is particularly "before", "before" It can be realized in any order, unless explicitly stated as etc. and the output of the previous process is not used in the later process. With regard to the operation flow in the claims, the specification, and the drawings, even if it is described using “first,” “next,” etc. for convenience, it means that it is essential to carry out in this order. is not.

10 Mobile System 50 Controller 52 Operation Unit 54 Display Unit 100 UAV
DESCRIPTION OF SYMBOLS 101 UAV main body 102 interface 104 control part 106 memory 110 gimbal 112 control part 114, 116, 118 driver 124, 126, 128 drive part 130 support mechanism 134, 136, 138 rotation mechanism 140 imaging part 160 lens apparatus 161 drive mechanism 162 control part 163 memories 220 and 230 imaging device 221 imaging device 222 control unit 223 memory 231 imaging device 232 control unit 233 memory 234 control unit 235 lens 300, 400, 500, 600 lens system 301, 401, 501, 601 first lens group 302, 402, 502, 602 Second lens group 311, 411, 511, 611 1a lens group 312, 412, 512, 612 1b lens group Pr Reflecting member 3000 Stabilizer 3001 Device holder 30 2 the mobile device 3003 Possession 3004 shutter button 3005 Record button 3006 operation button 3007 holder 3009 pan axis 3010 roll axis 3011 tilt axis 3013 a camera unit 3014 slot 3020 gimbal

Claims (10)

A first lens unit, an aperture stop, and a second lens unit having a positive refractive power, in order from the object side;
The first lens group includes, in order from the object side, a lens group 1a having negative refractive power, a reflecting member for bending an optical path, and a lens group 1b having positive refractive power.
The first lens group a, in order from the object side,
The first negative lens having a meniscus shape with the convex surface facing the object side, the second negative lens with the concave surface facing the image side, and the third negative lens, three negative single lenses,
The first b lens group includes at least one positive lens,
The second lens group includes four or more lenses including at least one cemented lens,
Assuming that the focal length of the entire system is f and the focal length of the first a lens group is f11, the conditional expression -1.8 <f11 / f <-1.25
Satisfying lens system. Assuming that the refractive index of the first negative lens and the second negative lens with respect to the d-line of the ith negative lens is Ni, and the Abbe number of the ith lens with the d-line is vi, the conditional expression N1> 1.8
N2> 1.7
v1> 30
v2> 30
(I is a natural number)
The lens system according to claim 1, which satisfies Assuming that the focal length of the second lens group is f2, the conditional expression 3.6 <f2 / f <5.6
The lens system according to claim 1 or 2, which satisfies Assuming that the radius of curvature of the image side surface of the first negative lens is R12 and the focal length of the first negative lens is f_1, the conditional expression 0.45 <R12 / | f_1 | <0.7
The lens system according to claim 1 or 2, which satisfies The conditional expression Npr> 1.8 where the refractive index for the d-line of the reflecting member is Npr.
The lens system according to claim 1 or 2, which satisfies The lens system according to claim 1, wherein at least one of the second negative lens and the third negative lens has an aspheric shape. A lens system according to claim 1 or 2;
An imaging device comprising an imaging element.   A movable body that moves with the lens system according to claim 1. The mobile according to claim 8, wherein the mobile is an unmanned aerial vehicle. A lens system according to claim 1 or 2;
A support mechanism for displaceably supporting the lens system.

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