CN111201466A

CN111201466A - Variable focal length lens system and imaging device

Info

Publication number: CN111201466A
Application number: CN201880066388.1A
Authority: CN
Inventors: 大竹基之; 松井拓未; C·威琦尔特; M·卡姆; 石冈学
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2017-10-17
Filing date: 2018-10-16
Publication date: 2020-05-26
Also published as: JPWO2019078221A1; WO2019078221A1; JP7140135B2

Abstract

The variable focal length lens system comprises the following components from an object side to an image plane side in sequence: a first lens unit configured by a lens having a rotationally symmetric shape; a second lens unit including a first freeform lens in which at least one lens surface is configured as a freeform surface; a third lens unit including a second freeform lens in which at least one lens surface is configured as a freeform surface; and a fourth lens unit having an aperture stop and constituted by a lens having a rotationally symmetric shape. The second lens unit and the third lens unit are movable in the Y-axis direction and in directions opposite to each other. The combined refractive power of the second lens unit and the third lens unit is variable, and the fourth lens unit is moved in the optical axis direction so that variation in the image plane position with variation in the combined refractive power is compensated.

Description

Variable focal length lens system and imaging apparatus

Technical Field

The present disclosure relates to a variable focal length lens system and an imaging apparatus.

Background

As a recording method in a camera, there is known a method of recording an object image by converting the light quantity of the object image formed on the plane of an imaging device by the imaging device into an electrical output of each photoelectric converter using a photoelectric converter such as a CCD (charge coupled device) or a CMOS (complex metal oxide semiconductor). With the progress of microfabrication technology in recent years, high speed of a Central Processing Unit (CPU), high integration of a recording medium, and the like have been achieved. Therefore, high-capacity image data that could not be processed before high-speed processing has been allowed. In particular, due to an increase in the speed of the CPU, aberration correction such as distortion or lateral chromatic aberration has been performed in the subject after shooting.

CITATION LIST

Patent document

Patent document 1: description of U.S. Pat. No.3305294

Patent document 2: japanese unexamined patent application publication No.2007-

Disclosure of Invention

It is desirable to develop a compact and high-performance zoom lens suitable for a camera.

It is desirable to provide a variable focal length lens system capable of achieving good imaging performance from the wide-angle end state to the telephoto end state with a small number of lenses, and an imaging apparatus including such a variable focal length lens system.

According to the variable focal length lens system of the embodiment of the present disclosure, in order from an object side to an image plane side, there are included: a first lens unit including a rotationally symmetric shaped lens; a second lens unit including a first free-form-surface lens in which at least one lens surface is a free-form surface; a third lens unit including a second free-form-surface lens in which at least one lens surface is a free-form surface; and a fourth lens unit having an aperture stop and including a rotationally symmetric shaped lens, wherein the first lens unit is coaxial with the fourth lens unit, and wherein a Z axis is an optical axis of the fourth lens unit, a Y axis is an axis on an image plane orthogonal to the Z axis, and an X axis is an axis on the image plane orthogonal to the Y axis and the Z axis, the second lens unit and the third lens unit are movable in a Y axis direction, and by moving in directions opposite to each other, so that a combined refractive power of the second lens unit and the third lens unit is variable, and the fourth lens unit is moved in the optical axis direction, so that a variation in an image plane position with a variation in the combined refractive power is compensated.

An imaging apparatus according to an embodiment of the present disclosure includes a variable focal length lens system and an imaging device that outputs an imaging signal based on an optical image formed by the variable focal length lens system. The variable focal length lens system is constituted by the above variable focal length lens system according to the embodiment of the present disclosure.

In the variable focal length lens system or the imaging apparatus according to the embodiment of the present disclosure, the first lens unit and the second lens unit each including a free-form surface are moved opposite to each other in a direction orthogonal to the optical axis, and thereby, the combined refractive power is changed. The fourth lens unit is moved in the optical axis direction so that the variation in the image plane position with the change in the combined refractive power is compensated.

Drawings

Fig. 1 is an explanatory diagram showing an outline of a variable focal length lens system according to an embodiment of the present disclosure.

Fig. 2 is a lens cross-sectional view showing a first configuration example of a variable focal length lens system according to the embodiment.

Fig. 3 is a point diagram of numerical example 1 in the wide-angle end state, in which specific numerical values are applied to the variable focal length lens system shown in fig. 2.

Fig. 4 is a point diagram in a telephoto end state of numerical example 1 in which specific numerical values are applied to the variable focal length lens system shown in fig. 2.

Fig. 5 is a diagram showing distortion in the wide-angle end state of numerical example 1 in which specific numerical values are applied to the variable focal length lens system shown in fig. 2.

Fig. 6 is a graph showing distortion in a telephoto end state of numerical example 1 in which a specific numerical value is applied to the variable focal length lens system shown in fig. 2.

Fig. 7 is a lens cross-sectional view showing a second configuration example of a variable focal length lens system according to the embodiment.

Fig. 8 is a point diagram of numerical example 2 in the wide-angle end state, in which specific numerical values are applied to the variable focal length lens system shown in fig. 7.

Fig. 9 is a point diagram in a telephoto end state of numerical example 2 in which specific numerical values are applied to the variable focal length lens system shown in fig. 7.

Fig. 10 is a diagram showing distortion of numerical example 2 in the wide-angle end state, in which specific numerical values are applied to the variable focal length lens system shown in fig. 7.

Fig. 11 is a graph showing distortion in a telephoto end state of numerical example 2 in which a specific numerical value is applied to the variable focal length lens system shown in fig. 7.

Fig. 12 is a lens cross-sectional view showing a third structural example of a variable focal length lens system according to the embodiment.

Fig. 13 is a point diagram of numerical example 3 in the wide-angle end state, in which specific numerical values are applied to the variable focal length lens system shown in fig. 12.

Fig. 14 is a point diagram in a telephoto end state of numerical example 3 in which specific numerical values are applied to the variable focal length lens system shown in fig. 12.

Fig. 15 is a diagram showing distortion in the wide-angle end state of numerical example 3 in which specific numerical values are applied to the variable focal length lens system shown in fig. 12.

Fig. 16 is a graph showing distortion in the telephoto end state of numerical example 3 in which a specific numerical value is applied to the variable focal length lens system shown in fig. 12.

Fig. 17 is a lens cross-sectional view showing a fourth configuration example of a variable focal length lens system according to the embodiment.

Fig. 18 is a point diagram showing numerical example 4 in the wide-angle end state, in which specific numerical values are applied to the variable focal length lens system shown in fig. 17.

Fig. 19 is a point diagram in a telephoto end state of numerical example 4 in which specific numerical values are applied to the variable focal length lens system shown in fig. 17.

Fig. 20 is a diagram showing distortion of numerical example 4 in the wide-angle end state, in which specific numerical values are applied to the variable focal length lens system shown in fig. 17.

Fig. 21 is a graph showing distortion in the telephoto end state of numerical example 4 in which a specific numerical value is applied to the variable focal length lens system shown in fig. 17.

Fig. 22 is a block diagram showing a configuration example of the imaging apparatus.

Fig. 23 is a block diagram showing an example of a schematic configuration of a vehicle control system.

Fig. 24 is a diagram for assistance in explaining an example of mounting positions of the vehicle exterior information detecting portion and the imaging portion.

Detailed Description

Some embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Note that the description is given in the following order.

1. Basic configuration of lens

2. Action and Effect

3. Examples of application to image forming apparatus

4. Numerical example of lens

5. Application example

6. Other examples

[1. basic configuration of lens ]

A variable focal length lens system (zoom lens) is known in which a plurality of movable lens groups are included, and by moving the plurality of movable lens groups in the optical axis direction, the focal length is changed while the image plane position is kept constant.

Further, a variable focal length lens system for moving a free-form surface lens having no rotational symmetry axis in a direction perpendicular to the optical axis to change the angle of view is also known (patent document 1 (U.S. patent No.3305294 specification) and patent document 2 (japanese unexamined patent application publication No. 2007-4063)).

However, patent document 1 describes only a conceptual configuration using a free-form surface lens, and does not describe the configuration of a specific variable focal length lens system.

Patent document 2 discloses a lens system in which two free-form-surface lenses are arranged at each of two positions to be divided into a zoom portion and a compensator portion, and the two free-form-surface lenses at each of the two positions are caused to move in different directions to change magnification.

In the lens system described in patent document 2, the number of free-form-surface lenses is up to four. Since the free-form surface is difficult to process, it is difficult to obtain stable optical quality including manufacturing when the number of lenses increases. Further, since each free-form-surface lens moves independently, it becomes difficult to control the position of each free-form-surface lens as the number of lenses increases.

Therefore, it is desirable to develop a variable focal length lens system capable of achieving good image forming performance from the wide-angle end state to the telephoto end state by using a small number of free-form-surface lenses.

A variable focal length lens system according to embodiments of the present disclosure described below relates to a variable angle of view lens system, and is particularly suitable for a zoom lens system: the zoom lens has an angle of view of about 15 to 20mm (converted to 35mm), an open F-number of about 2.8 to 5.6, and a zoom ratio of about 2 in a wide-angle end state where the angle of view becomes widest.

Fig. 1 shows an outline of a variable focal length lens system according to the present embodiment. Fig. 2 shows a variable focal length lens system 1 according to a first configuration example of the present embodiment. Fig. 7 shows a variable focal length lens system 2 of a second configuration example. Fig. 12 shows a variable focal length lens system 3 of a third configuration example. Fig. 17 shows a variable focal length lens system 4 of a fourth configuration example. Numerical value examples in which specific numerical values are applied to these configuration examples will be described later. In fig. 1 and the like, Z1 denotes an optical axis. An optical member such as a cover glass CG protecting the imaging device may be arranged between each of the variable focal length lens systems 1 to 4 and the image plane Simg. In addition to the cover glass CG, various optical filters GF including a low-pass filter, an infrared cut filter, and the like may be provided.

Hereinafter, the configuration of a variable focal length lens system according to an embodiment of the present disclosure, which corresponds to the variable focal length lens systems 1 to 4 of the respective configuration examples shown in fig. 2 and the like, will be described as appropriate. However, the technique of the present disclosure is not limited to the illustrated configuration example.

The variable focal length lens system according to the present embodiment basically includes four lens units, in order from the object side to the image plane side, a first lens unit G1, a second lens unit G2, a third lens unit G3 and a fourth lens unit G4.

The first lens unit G1 includes a rotationally symmetric shaped lens. It is desirable that the first lens unit G1 include at least one negative lens and a positive lens disposed closer to the image plane side than the negative lens.

The second lens unit G2 includes a first free-form-surface lens L2 in which at least one lens surface is a free-form surface.

The third lens unit G3 includes a second free-form-surface lens L3 in which at least one lens surface is a free-form surface.

The fourth lens unit G4 has an aperture stop St, and includes a rotationally symmetric shape lens.

The first lens unit G1 and the fourth lens unit G4 are arranged coaxially with each other.

A typical zoom lens includes a rotationally symmetric shaped lens, such as a spherical lens or an aspherical lens, and is configured such that at least two movable lens groups move in the optical axis direction. More specifically, the configuration is such that one movable lens group moves, and the other movable lens group moves such that the accompanying image plane position variation is compensated.

On the other hand, in the variable focal length lens system disclosed in patent document 2 and the like, four free-form-surface lenses are provided, and all of the four free-form-surface lenses are shifted in a direction perpendicular to the optical axis. Further, the total refractive power of the lens system is changed by shifting two free-form surface lenses disposed on the object side in opposite directions, and the accompanying change in the image surface position is compensated for by shifting the other two free-form surface lenses disposed on the image side in opposite directions.

In contrast, in the variable focal length lens system according to the present embodiment, the two free-form-surface lenses, i.e., the first free-form-surface lens L2 and the second free-form-surface lens L3, are moved in opposite directions to each other, which are perpendicular to the optical axis Z1. This causes the combined refractive powers of the two free-form-surface lenses to vary, and causes the accompanying variation in image plane position to be compensated for by the fourth lens unit G4 moving in the optical axis Z1 direction, to keep the image plane position constant.

In the variable focal length lens system according to the present embodiment, the free-form surface lens is movable (displaceable) in a direction substantially perpendicular to the optical axis Z1, the shape thereof changes according to the distance of movement, and the refractive power also changes.

The fourth lens unit G4 may include a plurality of lenses each having a rotationally symmetric shape. In this case, in the fourth lens unit G4, the lenses may be disposed coaxially with each other.

Here, in the variable focal length lens system according to the present embodiment, since a free-form surface lens, i.e., a rotationally asymmetric lens is used, the X-axis, the Y-axis, and the Z-axis are defined. As shown in fig. 1, the optical axis of the fourth lens unit G4 is defined as the Z-axis. An axis perpendicular to the Z axis on the image plane Simg is defined as a Y axis. An axis perpendicular to the Y axis and the Z axis on the image plane Simg is defined as an X axis. The three axes, i.e., the X, Y, and Z axes, intersect at an origin on the image plane.

Fig. 1 shows an outline of a change in lens position state of each lens unit from a wide-angle end state to a telephoto end state. Fig. 2 and the like show lens sections in the Y-Z plane and the X-Z plane in the wide-angle end state and the telephoto end state, respectively, of each lens unit. In the variable focal length lens system according to the present embodiment, when the lens position state changes from the wide-angle end state to the telephoto end state, the second lens unit G2, the third lens unit G3, and the fourth lens unit G4 move. At this time, the second lens unit G2 and the third lens unit G3 move in a state where the interval in the optical axis Z1 direction does not change, but at the same time move by different movement distances in the Y-axis direction perpendicular to the optical axis Z1. The fourth lens unit G4 moves in the optical axis Z1 direction.

Note that the first lens unit G1 is fixed.

In the present embodiment, the shape of the free-form surface is expressed using an X-Y polynomial equation. The sag Zsag of the lens surface in the Z-axis is represented by Z in the following equation (a). C3, … …, C53 each represent the coefficients of an X-Y polynomial equation. H denotes a distance from the optical axis Z1, and is expressed as H ═ X (X)²+Y²)^1/2. Z represents the amount of sag, R represents the radius of curvature, and K represents the conic constant.

[ mathematics 1]

As shown in fig. 2 and the like, the first free-form-surface lens L2 and the second free-form-surface lens L3 each have a shape symmetrical with respect to the Y-Z plane, which is a shape in which the refractive power continuously changes in the Y-axis direction. That is, the odd-order terms of Y are present, but the odd-order terms of X are not.

In addition, the variable focal length lens system according to the present embodiment is expected to satisfy a predetermined conditional expression or the like described later.

[2. action and Effect ]

Next, the action and effect of the variable focal length lens system according to the present embodiment will be described. In addition, a desired configuration of the variable focal length lens system according to the present embodiment will be described.

The effects described in the present specification are exemplary and not restrictive, and other effects may be provided.

In the variable focal length lens system according to the present embodiment, four lens units are included as a whole, and the configuration of each lens unit is optimized by appropriately using a free-form surface. Therefore, good image forming performance from the wide-angle end state to the telephoto end state can be achieved with a small number of lenses.

In the variable focal length lens system according to the present embodiment, in the case where the variation in refractive power increases when the first and second free-form-surface lenses L2 and L3 are displaced, the zoom ratio (focal length in the telephoto end state/focal length in the wide-angle end state) increases, but the aberration increases.

Therefore, the variable focal length lens system according to the present embodiment is expected to satisfy the following conditional expressions (1) and (2).

Wherein,

is the refractive power of the first free-form-surface lens L2 in the X-axis direction in the wide-angle end state,

is the refractive power of the second free-form-surface lens L3 in the X-axis direction in the wide-angle end state, and "fw" is the total focal length of the lens system in the wide-angle end state.

Further, it is desirable that the variable focal length lens system according to the present embodiment satisfies the following conditional expressions (3) and (4).

Wherein,

is the refractive power in the X-axis direction of the first free-form-surface lens L2 in the telephoto end state,

is the refractive power of the second free-form-surface lens L3 in the telephoto end state in the X-axis direction, and "ft" is the total focal length of the lens system in the telephoto end state.

Here, since the free-form surface does not have a rotational symmetry axis, the definition of the refractive power will be described. In the present embodiment, the light beam passing on the optical axis of the fourth lens unit G4 after passing through the first free-form-surface lens L2 and the second free-form-surface lens L3 is an on-axis ray. The power of the on-axis rays is the paraxial power of the first free-form-surface lens L2 and the second free-form-surface lens L3. Then, skew ray tracing (skew ray tracing) is performed. Therefore, the refractive powers are also calculated in the X-axis direction and the Y-axis direction, respectively.

The above-described conditional expressions (1) to (4) are conditional expressions that specify the powers of the first free-form-surface lens L2 and the second free-form-surface lens L3, and in the case where the powers exceed the respective upper limit values, various aberrations in the wide-angle end state and the telephoto end state become large. In particular, in the wide-angle end state, distortion occurring in the periphery of the screen becomes large. At this time, although correction may be performed by combining distortion correction by signal processing in the imaging apparatus, the image quality deteriorates. More specifically, since the number of recording pixels in the imaging device is determined, the resolution is reduced due to the stretching effect. Further, in the telephoto end state, decentering coma aberration occurring at the center of the screen becomes large.

In the variable focal length lens system according to the present embodiment, if the refractive index difference between the X-axis direction and the Y-axis direction of the first free-form-surface lens L2 and the second free-form-surface lens L3 increases, the focal length difference between the X-axis direction and the Y-axis direction increases.

Therefore, the variable focal length lens system according to the present embodiment is expected to satisfy the following conditional expressions (5) and (6).

Wherein,

is a combined refractive power in the X-axis direction of the first free-form-surface lens L2 and the second free-form-surface lens L3 in the wide-angle end state,

is a combined refractive power in the Y-axis direction of the first free-form-surface lens L2 and the second free-form-surface lens L3 in the wide-angle end state,

is the combined refractive power in the X-axis direction of the first free-form-surface lens L2 and the second free-form-surface lens L3 in the telephoto end state,

is the combined refractive power in the Y-axis direction of the first and second free-form-surface lenses L2 and L3 in the telephoto end state, "fw" is the total focal length of the lens system in the wide-angle end state, and "ft" is the total focal length of the lens system in the telephoto end state.

When any one of the upper limit value and the lower limit value of conditional expression (5) and conditional expression (6) is exceeded, the viewing angle difference between the X-axis direction and the Y-axis direction becomes large, which is not preferable.

In the variable focal length lens system according to the present embodiment, it is desirable that the fourth lens unit G4 be moved in the optical axis direction in accordance with the object distance to compensate for the shift in the focal position (to perform focusing).

In particular, in order to achieve high performance, if the difference in focal length between the X-axis direction and the Y-axis direction is small, the shift of the focal position in the X-axis direction and the Y-axis direction is small even if the object position changes from the infinity point to the close-distance point. When the difference in focal length between the X-axis direction and the Y-axis direction becomes large, the focal position shifts. Therefore, the variable focal length lens system according to the present embodiment is expected to satisfy the following conditional expressions (7) and (8).

Wherein,

is a combined refractive power in the X-axis direction of the first free-form-surface lens L2 and the second free-form-surface lens L3 in the telephoto end state, and

is a combined refractive power in the Y-axis direction of the first free-form-surface lens L2 and the second free-form-surface lens L3 in the telephoto end state.

When any one of the upper limit value and the lower limit value of the above-described conditional expressions (7) and (8) is exceeded, even if the focus positions in the X-axis direction and the Y-axis direction are adjusted at the infinity point, the shift of the focus position becomes large at the shortest photographing point.

The variable focal length lens system according to the present embodiment is expected to satisfy the following conditional expressions (9) and (10) for balancing between size reduction and performance enhancement.

1.2＜Δ2/ft＜2.5……(9)

0.8＜Δ3/ft＜1.6……(10)

Where "Δ 2" is a moving distance of the second lens unit L2 in the Y-axis direction when the lens position state changes from the wide-angle end state to the telephoto end state, "Δ 3" is a moving distance of the third lens unit L3 in the Y-axis direction when the lens position state changes from the wide-angle end state to the telephoto end state, and "ft" is a total focal length of the lens system in the telephoto end state.

When any of the upper limit values of conditional expressions (9) and (10) is exceeded, the moving distance of the second lens unit L2 and the moving distance of the third lens unit L3 become too large, and the volume of the entire lens system becomes large. In contrast, when any one of the lower limit values of conditional expressions (9) and (10) is exceeded, the moving distance becomes small, which makes it difficult to correct the aberration occurring in the free-form surface and to sufficiently achieve high performance.

In the variable focal length lens system according to the present embodiment, it is preferable that the first lens unit G1 include a lens of a rotationally symmetric shape, and include at least one negative lens, and a positive lens disposed closer to the image plane side than the negative lens. This makes it easier to achieve favorable image forming performance in a wide-angle area.

In the variable focal length lens system according to the present embodiment, the performance is further improved by setting the aperture stop St closest to the object side in the fourth lens unit G4. More specifically, since the off-axis light flux passing through the two free-form-surface lenses becomes close to the optical axis Z1, the amount of occurrence of off-axis aberration is small, and high performance can be achieved.

In the variable focal length lens system according to the present embodiment, in order to favorably correct chromatic aberration in the wide-angle end state, it is desirable to use a glass material having high anomalous dispersibility in the fourth lens unit G4.

In the variable focal length lens system according to the present embodiment, the position shift of an image is allowed by moving one lens unit (fourth lens unit G4) out of the lens units included in the lens system, or by moving a part of lens elements in one lens unit (fourth lens unit G4) in a direction substantially perpendicular to the optical axis Z1 as a shift lens group.

The shift lens group may be used in combination with a detection system, a calculation system, and a drive system, and may be used as an image blur compensation camera that compensates for image blur caused by hand shake or the like occurring at the time of shutter release.

In this case, the detection system detects the shift angle of the camera and outputs image blur information. The computing system outputs lens position information required to compensate for image blur based on the image blur information. The shift lens group is a lens system corrected so as to reduce variation in performance when shifting the shift lens group. The driving system supplies a driving amount to the shift lens group based on the lens position information.

In addition, in the variable focal length lens system according to the present embodiment, as the optical filter GF, a low-pass filter may be further provided to prevent moire from occurring on the image plane side, or an infrared cut filter may be further provided according to the spectral sensitivity characteristic of the imaging device on the image plane side.

[3. example applied to image Forming apparatus ]

Next, an example in which the variable focal length lens systems 1 to 4 are applied to an imaging apparatus will be described.

Fig. 22 illustrates a configuration example of an imaging apparatus 100 to which any one of the variable focal length lens systems 1 to 4 according to the present embodiment is applied. The imaging apparatus 100 is, for example, a digital still camera, and includes a camera block 10, a camera signal processor 20, an image processor 30, an LCD (liquid crystal display) 40, an R/W (reader/writer) 50, a CPU (central processing unit) 60, an input section 70, and a lens driving control section 80.

The camera block 10 has an imaging function. The camera block 10 includes an optical system and an imaging device 12. The optical system includes an imaging lens 11. The imaging device 12 is a CCD (charge coupled device), a CMOS (complementary metal oxide semiconductor), or the like. The imaging device 12 converts an optical image formed by the imaging lens 11 into an electric signal to output an imaging signal (image signal) based on the optical image. Any one of the variable focal length lens systems 1 to 4 according to the configuration examples illustrated in fig. 2, 7, 12, and 17, respectively, may be applied to the imaging lens 11.

The camera signal processor 20 performs various signal processes on the image signal output from the imaging device 12. Various signal processing includes analog-to-digital conversion, noise removal, image quality correction, conversion into a luminance signal, and conversion into a color difference signal.

The image processor 30 performs processing of recording and reproducing image signals. The image processor 30 performs compression encoding and expansion decoding processing of the image signal based on a predetermined image data format, such as conversion processing of a data specification of resolution, and the like.

The LCD 40 has a function of displaying various types of data such as an operation state performed by a user on the input section 70, a photographed image, and the like. The R/W50 writes the image data encoded by the image processor 30 into the memory card 1000, and reads the image data recorded on the memory card 1000. The memory card 1000 is, for example, a semiconductor memory that is attachable to and detachable from a slot coupled with the R/W50.

The CPU60 functions as a control processor that controls each circuit block provided in the image forming apparatus 100. The CPU60 controls each circuit block based on an instruction input signal from the input section 70 and the like. The input section 70 includes various switches on which a user performs a predetermined operation or the like. The input section 70 includes, for example, a shutter release button for performing a shutter operation, a selection switch for selecting an operation mode, and the like. The input section 70 is configured to output an instruction input signal to the CPU60 based on an operation performed by the user. The lens driving controller 80 controls driving of the lens disposed in the camera block 10. The lens drive controller 80 controls a motor and the like, not shown, based on a control signal from the CPU 60. A motor, not shown, drives each lens of the imaging lens 11.

The operation of the image forming apparatus 100 is described below.

In the standby state of photographing, under the control of the CPU60, an image signal photographed by the camera block 10 is output to the LCD 40 via the camera signal processor 20, and is displayed as an image passing through the camera. Further, for example, when an instruction input signal for zooming, focusing, or the like is input from the input section 70, the CPU60 outputs a control signal to the lens drive controller 80, and a predetermined lens of the imaging lens 11 is moved based on the control performed by the lens drive controller 80.

When a shutter, not shown, of the camera block 10 is operated by an instruction input signal from the input section 70, a photographed image signal is output from the camera signal processor 20 to the image processor 30, and is subjected to compression encoding processing to be converted into digital data having a predetermined data format. The converted data is output to the R/W50 and written to the memory card 1000.

Note that, for example, in a case where the shutter release button of the input section 70 is half-pressed, or in a case where it is fully pressed for recording (shooting), the lens drive controller 80 moves a predetermined lens of the imaging lens 11 based on a control signal from the CPU60, thereby performing focusing.

In the case of reproducing image data recorded on the memory card 1000, predetermined image data is read from the memory card 1000 through the R/W50 in accordance with an operation performed on the input section 70. The predetermined image data is subjected to the expansion decoding process by the image processor 30. Thereafter, the reproduced image signal is output to the LCD 40, and the reproduced image is displayed.

It is to be noted that, in the above-described embodiments, an example in which the imaging apparatus is applied to a digital still camera or the like is described; however, the application range of the imaging apparatus is not limited to the digital still camera, and it is applicable to other various imaging apparatuses. For example, it can be applied to a digital single-lens reflex camera, a digital non-reflex camera, a digital video camera, a surveillance camera, and the like. Further, it can be widely applied to a camera unit of a mobile phone having a built-in camera, a digital input-output device such as an information terminal having a built-in camera, and the like. Further, it can be applied to a lens-interchangeable camera.

Examples of the implementation

[4. numerical example of lens ]

Next, specific numerical examples of the variable focal length lens systems 1 to 4 according to the present embodiment will be described. Here, numerical examples in which specific numerical values are applied to the variable focal length lens systems 1 to 4 having the configuration examples shown in fig. 2, 7, 12, and 17, respectively, will be described.

Note that the meanings of the following symbols and the like described in tables, explanations and the like are as follows. "surface number" denotes the number of the i-th surface numbered from the object side to the image surface. "radius of curvature" means the value of the paraxial radius of curvature (mm) of the ith surface. "face separation" means the on-axis separation (center thickness of lens or air separation) between the ith face and the (i +1) th face. "refractive index" means a value of a refractive index with respect to e-line (wavelength of 546nm) of a lens or the like from the i-th surface. The "abbe number" represents a value of abbe number of a lens or the like from the i-th surface with respect to the e-line.

In the "surface shape" column, the kind of the surface shape of each lens surface is indicated. The variable focal length lens systems 1 to 4 according to the present embodiment include an aspherical surface represented by the following equation (B) in addition to a free-form surface represented by the X-Y polynomial equation of the above equation (a). Note that in equation (B), H represents a distance from the optical axis Z1, and is expressed as H ═ X (X)²+Y²)^1/2Z denotes a sag amount, R denotes a curvature radius, K denotes a conic constant, and A, B, C and D each denote an aspherical surface coefficient.

[ mathematics 2]

In each table showing each numerical example, "E-n" represents an exponential expression with a base 10, that is, "negative nth power of 10", for example, "0.12345E-05" represents "0.12345 × (negative fifth power of 10)".

[ Structure common to numerical examples ]

Each of the variable focal length lens systems 1 to 4 of numerical examples 1 to 4 applied below has a configuration satisfying < 1. basic configuration of lens > as described above.

That is, each of the variable focal length lens systems 1 to 4 basically includes four lens units, a first lens unit G1, a second lens unit G2, a third lens unit G3, and a fourth lens unit G4 in order from the object side to the image plane side. The first lens unit G1 includes a rotationally symmetric shaped lens. The second lens unit G2 includes a first free-form-surface lens L2 in which at least one lens surface is a free-form surface. The third lens unit G3 includes a second free-form-surface lens L3 in which at least one lens surface is a free-form surface. The fourth lens unit G4 has an aperture stop St, and includes a rotationally symmetric shape lens.

As shown in fig. 1, in each of the variable focal length lens systems 1 to 4, when the lens position state changes from the wide-angle end state to the telephoto end state, the second lens unit G2, the third lens unit G3, and the fourth lens unit G4 move. At this time, the second lens unit G2 and the third lens unit G3 move without changing the interval in the optical axis Z1 direction, but at the same time move by different moving distances in the Y-axis direction perpendicular to the optical axis Z1. The fourth lens unit G4 moves in the optical axis Z1 direction.

[ numerical example 1]

In the variable focal length lens system 1 shown in fig. 2, the first lens unit G1 includes a meniscus negative lens L11 having a concave surface facing the image plane side, a negative lens L12 having a concave surface facing the image plane side, and a positive lens L13 having a concave surface facing the object side.

The second lens unit G2 includes a first free-form-surface lens L2 having a shape symmetrical with respect to the optical axis Z1 in the X-Z section and an asymmetrical shape in the Y-Z section.

The third lens unit G3 includes a second free-form-surface lens L3 having a shape symmetrical with respect to the optical axis in the X-Z section and an asymmetrical shape in the Y-Z section.

The fourth lens unit G4 includes an aperture stop St and three lenses, i.e., a biconvex lens L41, a biconcave lens L42, and a biconvex lens L43.

The aperture stop St is disposed between the third lens unit G3 and the fourth lens unit G4. When the lens position state changes, the respective lenses of the fourth lens unit G4 other than the aperture stop St move integrally.

The second lens unit G2 and the third lens unit G3 are movable by different movement distances in the Y-axis direction, and the fourth lens unit G4 is moved in the optical axis direction so that the accompanying image plane position variation is compensated.

Table 1 describes basic lens data of numerical example 1 in which specific numerical values are applied to the variable focal length lens system 1. As described in table 1, in numerical example 1, the lens surfaces (seventh surface to tenth surface) of the second lens unit G2 and the third lens unit G3 are each a free-form surface (X-Y polynomial surface). In numerical example 1, the lens surfaces (third surface to sixth surface) of the lenses L12 and L13 included in the first lens unit G1 are each an aspherical surface. The lens surfaces (twelfth to seventeenth surfaces) of the lenses L41, L42, and L43 included in the fourth lens unit G4 are each aspherical. Table 2 and table 3 describe the coefficients of the free-form surface and the aspherical surface.

As the focal length changes, the values of the face spacings D11 and D17 each change. As data when the focal length is changed, table 4 includes a total focal length of the lens system in the X-axis direction, a total focal length of the lens system in the Y-axis direction, a value of D11, a value of D17, a shift amount of the first free-form-surface lens L2 in the Y-axis direction, and a shift amount of the second free-form-surface lens L3 in the Y-axis direction.

In addition, as data when the focal length is changed, table 5 includes the total focal length of the lens system in the X-axis direction and the Y-axis direction, the focal length of the first free-form-surface lens L2 in the X-axis direction and the Y-axis direction, and the focal length of the second free-form-surface lens L3 in the X-axis direction and the Y-axis direction. In addition, the combined focal lengths of the first free-form-surface lens L2 and the second free-form-surface lens L3 in the X-axis direction and the Y-axis direction are also included in table 5.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

[ Table 5]

Further, values relating to the respective conditional expressions in the above numerical example 1 are shown below. In numerical example 1, the value of each conditional expression is within a numerical range.

(9)Δ2/ft＝1.757

(10)Δ3/ft＝1.523

Fig. 3 is a point diagram of numerical example 1 in the wide-angle end state. Fig. 4 is a dot sequence diagram of numerical example 1 in a telephoto end state. Fig. 5 shows distortion of numerical example 1 in the wide-angle end state. Fig. 6 shows distortion in the telephoto end state of numerical example 1. Note that distortion represents aberration by an equal solid angle projection method.

As can be seen from the respective aberration diagrams, in numerical example 1, it is clear that the respective aberrations are favorably corrected in an appropriate balance in the wide-angle end state and the telephoto end state, and excellent image forming performance is provided.

[ numerical example 2]

In the variable focal length lens system 2 shown in fig. 7, the first lens unit G1 includes a meniscus negative lens L11 having a concave surface facing the image plane side, a negative lens L12 having a concave surface facing the image plane side, and a positive lens L13 having a concave surface facing the object side.

The fourth lens unit G4 includes an aperture stop St and three lenses, a biconvex lens L41, a biconcave lens L42, and a biconvex lens L43.

Table 6 describes basic lens data of numerical example 2 in which specific numerical values are applied to the variable focal length lens system 2. As described in table 6, in numerical example 2, the lens surfaces (seventh surface to tenth surface) of the second lens unit G2 and the third lens unit G3 are each a free-form surface (X-Y polynomial surface). In numerical example 2, the lens faces (third face to sixth face) of the lenses L12 and L13 included in the first lens unit G1 are each an aspherical face. The lens surfaces (twelfth to seventeenth surfaces) of the lenses L41, L42, and L43 included in the fourth lens unit G4 are each aspherical. Tables 7 and 8 describe the coefficients of the free-form surface and the aspherical surface.

As the focal length changes, the values of the face spacings D11 and D17 each change. As data when the focal length is changed, table 9 includes a total focal length of the lens system in the X-axis direction, a total focal length of the lens system in the Y-axis direction, a value of D11, a value of D17, a shift amount of the first free-form-surface lens L2 in the Y-axis direction, and a shift amount of the second free-form-surface lens L3 in the Y-axis direction.

In addition, as data when the focal length is changed, table 10 includes the total focal length of the lens system in the X-axis direction and the Y-axis direction, the focal length of the first free-form-surface lens L2 in the X-axis direction and the Y-axis direction, and the focal length of the second free-form-surface lens L3 in the X-axis direction and the Y-axis direction. In addition, table 10 includes the combined focal lengths of the first and second free-form-surface lenses L2 and L3 in the X-axis direction and the Y-axis direction.

[ Table 6]

[ Table 7]

[ Table 8]

[ Table 9]

[ Table 10]

Further, values relating to the respective conditional expressions in the above numerical example 2 are shown below. In numerical example 2, the value of each conditional expression is within a numerical range.

(9)Δ2/ft＝1.744

(10)Δ3/ft＝1.100

Fig. 8 is a point diagram of numerical example 2 in the wide-angle end state. Fig. 9 is a dot sequence diagram in the telephoto end state of numerical example 2. Fig. 10 shows distortion of numerical example 2 in the wide-angle end state. Fig. 11 shows distortion in the telephoto end state of numerical example 2. Note that distortion represents aberration by an equal solid angle projection method.

As can be seen from the respective aberration diagrams, in numerical example 2, it is clear that the respective aberrations are favorably corrected in an appropriate balance in the wide-angle end state and the telephoto end state, and excellent image forming performance is provided.

[ numerical example 3]

In the variable focal length lens system 3 shown in fig. 12, the first lens unit G1 includes a meniscus negative lens L11 having a concave surface facing the image plane side, a negative lens L12 having a concave surface facing the image plane side, and a positive lens L13 having a concave surface facing the object side.

Table 11 describes basic lens data of numerical example 3 in which specific numerical values are applied to the variable focal length lens system 3. As described in table 11, in numerical example 3, the lens surfaces (seventh surface to tenth surface) of the second lens unit G2 and the third lens unit G3 are each a free-form surface (X-Y polynomial surface). In numerical example 3, the lens faces (third face to sixth face) of the lenses L12 and L13 included in the first lens unit G1 are each an aspherical face. The lens surfaces (twelfth to seventeenth surfaces) of the lenses L41, L42, and L43 included in the fourth lens unit G4 are each aspherical. Tables 12 and 13 describe coefficients of the free-form surface and the aspherical surface.

As the focal length changes, the values of the face spacings D11 and D17 each change. As data when the focal length is changed, table 14 includes a total focal length of the lens system in the X-axis direction, a total focal length of the lens system in the Y-axis direction, a value of D11, a value of D17, a shift amount of the first free-form-surface lens L2 in the Y-axis direction, and a shift amount of the second free-form-surface lens L3 in the Y-axis direction.

In addition, as data when the focal length is changed, table 15 includes the total focal length of the lens system in the X-axis direction and the Y-axis direction, the focal length of the first free-form-surface lens L2 in the X-axis direction and the Y-axis direction, and the focal length of the second free-form-surface lens L3 in the X-axis direction and the Y-axis direction. In addition, table 15 includes the combined focal lengths of the first and second free-form-surface lenses L2 and L3 in the X-axis direction and the Y-axis direction.

[ Table 11]

[ Table 12]

[ Table 13]

[ Table 14]

[ Table 15]

Further, values relating to the respective conditional expressions in the above numerical example 3 are shown below. In numerical example 3, the value of each conditional expression is within a numerical range.

(9)Δ2/ft＝1.685

(10)Δ3/ft＝1.187

Fig. 13 is a point diagram of numerical example 3 in the wide-angle end state. Fig. 14 is a dot sequence diagram in the telephoto end state of numerical example 3. Fig. 15 shows distortion in the wide-angle end state of numerical example 3. Fig. 16 shows distortion in the telephoto end state of numerical example 3. Note that distortion represents aberration by an equal solid angle projection method.

As can be seen from the respective aberration diagrams, in numerical example 3, it is clear that the respective aberrations are favorably corrected in an appropriate balance in the wide-angle end state and the telephoto end state, and excellent image forming performance is provided.

[ numerical example 4]

In the variable focal length lens system 4 illustrated in fig. 17, the first lens unit G1 includes a meniscus negative lens L11 having a concave surface facing the image plane side, a negative lens L12 having a concave surface facing the image plane side, and a positive lens L13 having a concave surface facing the object side.

Table 16 describes basic lens data of numerical example 4 in which specific numerical values are applied to the variable focal length lens system 4. As described in table 16, in numerical example 4, the lens surfaces (seventh surface to tenth surface) of the second lens unit G2 and the third lens unit G3 are each a free-form surface (X-Y polynomial surface). In numerical example 4, the lens faces (third face to sixth face) of the lenses L12 and L13 included in the first lens unit G1 are each an aspherical face. The lens surfaces (twelfth to seventeenth surfaces) of the lenses L41, L42, and L43 included in the fourth lens unit G4 are each aspherical. Tables 17 and 18 describe coefficients of free-form surfaces and aspherical surfaces.

As the focal length changes, the values of the face spacings D11 and D17 each change. As data when the focal length is changed, table 19 includes a total focal length of the lens system in the X-axis direction, a total focal length of the lens system in the Y-axis direction, a value of D11, a value of D17, a shift amount of the first free-form-surface lens L2 in the Y-axis direction, and a shift amount of the second free-form-surface lens L3 in the Y-axis direction.

In addition, as data at the time of focal length change, the table 20 includes the total focal length of the lens system in the X-axis direction and the Y-axis direction, the focal length of the first free-form-surface lens L2 in the X-axis direction and the Y-axis direction, and the focal length of the second free-form-surface lens L3 in the X-axis direction and the Y-axis direction. In addition, table 20 includes the combined focal lengths of the first and second free-form-surface lenses L2 and L3 in the X-axis direction and the Y-axis direction.

[ Table 16]

[ Table 17]

[ Table 18]

[ Table 19]

[ Table 20]

Further, values relating to the respective conditional expressions in the above numerical example 4 are shown below. In numerical example 4, the value of each conditional expression is within a numerical range.

(9)Δ2/ft＝1.620

(10)Δ3/ft＝1.154

Fig. 18 is a point diagram of numerical example 4 in the wide-angle end state. Fig. 19 is a dot sequence diagram in the telephoto end state of numerical example 4. Fig. 20 shows distortion of numerical example 4 in the wide-angle end state. Fig. 21 shows distortion in the telephoto end state of numerical example 4. Note that distortion represents aberration by an equal solid angle projection method.

As can be seen from the respective aberration diagrams, in numerical example 4, it is clear that the respective aberrations are favorably corrected in an appropriate balance in the wide-angle end state and the telephoto end state, and excellent image forming performance is provided.

[5. application example ]

The techniques according to embodiments of the present disclosure may be applied to various products. For example, the techniques according to embodiments of the present disclosure may be implemented in the form of a device mounted on any kind of moving body. Examples of the moving body include automobiles, electric automobiles, hybrid electric automobiles, motorcycles, bicycles, personal mobile devices, airplanes, unmanned planes, ships, robots, construction machines, and agricultural machines (tractors).

Fig. 23 is a block diagram showing an example of a schematic configuration of a vehicle control system 7000 which is an example of a mobile body control system to which the technique of the embodiment of the present invention can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected to each other via a communication network 7010. In the example shown in fig. 23, the vehicle control system 7000 includes a drive system control unit 7100, a vehicle body system control unit 7200, a battery control unit 7300, an outside-vehicle information detection unit 7400, an inside-vehicle information detection unit 7500, and an integrated control unit 7600. The communication network 7010 that connects the plurality of control units to each other may be, for example, an in-vehicle communication network conforming to any standard, such as a Controller Area Network (CAN), a Local Interconnect Network (LIN), a Local Area Network (LAN), FlexRay (registered trademark), or the like.

Each control unit includes: a microcomputer that performs arithmetic processing according to various programs; a storage section that stores a program executed by the microcomputer, parameters for various operations, and the like; and a drive circuit that drives various controlled devices. Each control unit further comprises: a network interface (I/F) for communicating with other control units via a communication network 7010; and a communication I/F for communicating with devices, sensors, and the like inside and outside the vehicle by wired communication or radio communication. The functional configuration of the integrated control unit 7600 shown in fig. 23 includes a microcomputer 7610, a general communication I/F7620, an exclusive communication I/F7630, a positioning section 7640, a beacon receiving section 7650, an in-vehicle apparatus I/F7660, a sound/image output section 7670, an in-vehicle network I/F7680, and a storage section 7690. The other control units similarly include a microcomputer, a communication I/F, a storage section, and the like.

The drive system control unit 7100 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 7100 has a function of a control device for controlling: a driving force generating device (such as an internal combustion engine, a driving motor, etc.) for generating a driving force of the vehicle, a driving force transmitting mechanism for transmitting the driving force to wheels, a steering mechanism for adjusting a steering angle of the vehicle, a braking device for generating a braking force of the vehicle, etc. The drive system control unit 7100 may have a function as a control device of an Antilock Brake System (ABS), an Electronic Stability Control (ESC), or the like.

The drive system control unit 7100 is connected to a vehicle state detection section 7110. The vehicle state detecting section 7110 includes, for example, at least one of a gyro sensor that detects an angular velocity of an axial rotational motion of a vehicle body, an acceleration sensor that detects an acceleration of the vehicle, and a sensor for detecting an operation amount of an accelerator pedal, an operation amount of a brake pedal, a steering angle of a steering wheel, an engine speed, a rotational speed of a wheel, or the like. The drive system control section 7100 performs arithmetic processing using a signal input from the vehicle state detection section 7110, and controls the internal combustion engine, the drive motor, the electric power steering apparatus, the brake apparatus, and the like.

The vehicle body system control unit 7200 controls the operations of various devices provided to the vehicle body according to various programs. For example, the main body system control unit 7200 functions as a control device of a keyless entry system, a smart key system, a power window device, or various lamps such as a headlamp, a backup lamp, a brake lamp, a turn signal, a fog lamp, or the like. In this case, a signal of a radio wave transmitted from a mobile device as a substitute for a key or various switches may be input to the main body system control unit 7200. The main body system control unit 7200 receives these input radio waves or signals, and controls a door lock device, a power window device, a lamp, and the like of the vehicle.

The battery control unit 7300 controls the secondary battery 7310 as a power source for driving the motor according to various programs. For example, information on the battery temperature, the battery output voltage, the amount of charge remaining in the battery, and the like is provided from a battery device including the secondary battery 7310 to the battery control unit 7300. Battery control unit 7300 performs arithmetic processing using these signals, and performs control for adjusting the temperature of secondary battery 7310 or control of a cooling device or the like provided to the battery device.

Vehicle exterior information detecting section 7400 detects information outside the vehicle including vehicle control system 7000. For example, the vehicle exterior information detecting section 7400 is connected to at least one of the imaging section 7410 and the vehicle exterior information detecting section 7420. The imaging section 7410 includes at least one of a time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The off-vehicle information detecting section 7420 includes, for example, at least one of an environment sensor for detecting the current atmospheric condition or weather condition and a surrounding information detecting sensor for detecting another vehicle, an obstacle, a pedestrian, and the like on the periphery of the vehicle including the vehicle control system 7000.

For example, the environmental sensor may be at least one of a raindrop sensor that detects rain, a fog sensor that detects fog, a sunshine sensor that detects the degree of sunshine, and a snow sensor that detects snowfall. The peripheral information detection sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR device (light detection and ranging device, or laser imaging detection and ranging device). The imaging section 7410 and the vehicle exterior information detecting section 7420 may be provided as separate sensors or devices, or may be provided as a device in which a plurality of sensors or devices are integrated.

Fig. 24 is a diagram showing an example of the arrangement positions of the imaging section 7410 and the vehicle exterior information detecting section 7420. The

imaging portions

7910, 7912, 7914, 7916, and 7918 are arranged, for example, at least one of positions on a front nose, side mirrors, a rear bumper, and a rear door of the vehicle 7900 and a position on an upper portion of a windshield within the vehicle interior. The imaging portion 7910 provided on the front head and the imaging portion 7918 provided on the upper portion of the windshield inside the vehicle mainly obtain an image of the front of the vehicle 7900. The

imaging portions

7912 and 7914 provided on the side view mirror mainly obtain images of the side of the vehicle 7900. The imaging portion 7916 provided on the rear bumper or the rear door mainly acquires an image of the rear of the vehicle 7900. The imaging portion 7918 provided at the upper portion of the windshield inside the vehicle is mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, and the like.

Incidentally, fig. 24 describes an example of the shooting ranges of the

respective imaging portions

7910, 7912, 7914, and 7916. The imaging range a indicates an imaging range of the imaging portion 7910 set to the anterior nose. The imaging ranges B and C represent imaging ranges provided to the

imaging portions

7912 and 7914 of the side view mirror, respectively. The imaging range D indicates an imaging range of the imaging portion 7916 provided on the rear bumper or the rear door. For example, by superimposing the image data imaged by the

imaging portions

7910, 7912, 7914, and 7916, a bird's eye view image of the vehicle 7900 viewed from above can be obtained.

The vehicle exterior

information detecting portions

7920, 7922, 7924, 7926, 7928, and 7930 provided at the front, rear, side, and corners of the vehicle 7900 and the upper portion of the windshield inside the vehicle may be, for example, ultrasonic sensors or radar devices. The vehicle exterior

information detecting portions

7920, 7926 and 7930 provided at the front end of the vehicle 7900, the rear bumper, the rear door of the vehicle 7900 and the upper portion of the windshield inside the vehicle may be LIDAR devices, for example. These vehicle exterior information detecting portions 7920 to 7930 are mainly used for detecting a preceding vehicle, a pedestrian, an obstacle, and the like.

The description is continued with reference to fig. 23. The vehicle exterior information detecting section 7400 causes the imaging section 7410 to image an image outside the vehicle and receives the imaged image data. Further, the vehicle exterior information detecting section 7400 receives detection information from the vehicle exterior information detecting section 7420 connected to the vehicle exterior information detecting section 7400. When the vehicle exterior information detecting section 7420 is an ultrasonic sensor, a radar device, or a LIDAR device, the vehicle exterior information detecting section 7400 transmits ultrasonic waves, electromagnetic waves, or the like, and receives information of the received reflected waves. The vehicle exterior information detecting section 7400 may perform processing for detecting an object such as a person, a vehicle, an obstacle, a sign, or a character on a road surface or processing for detecting a distance to the object based on the received information. The vehicle exterior information detecting section 7400 may perform environment recognition processing for recognizing rainfall, fog, road surface conditions, and the like based on the received information. The vehicle exterior information detecting section 7400 may calculate the distance to the vehicle exterior object based on the received information.

The vehicle exterior information detecting section 7400 may perform image recognition processing for recognizing a person, a vehicle, an obstacle, a sign, characters on a road surface, or the like, or processing for detecting a distance to the person, the vehicle, the obstacle, the sign, the characters on the road surface, or the like, based on the received image data. The vehicle exterior information detecting section 7400 may perform processing such as distortion correction or position alignment on the received image data, and synthesize the image data captured by the plurality of different imaging sections 7410 to generate a bird's-eye view image or a panoramic image. The vehicle exterior information detecting section 7400 may also perform viewpoint conversion processing using image data captured by the imaging section 7410 including a different imaging section.

The in-vehicle information detection portion 7500 detects information of the inside of the vehicle. The in-vehicle information detecting section 7500 is connected to, for example, a driver state detecting section 7510 that detects the state of the driver. The driver state detection portion 7510 may include a camera that images the driver, a biosensor that detects biological information of the driver, a microphone that collects sound inside the vehicle, and the like. The biosensor is provided, for example, in a seat surface, a steering wheel, or the like, and detects biological information of an occupant seated in the seat or a driver holding the steering wheel. The in-vehicle information detecting section 7500 can calculate the degree of fatigue or concentration of the driver or determine whether the driver is dozing, based on the detection information input from the driver state detecting section 7510. The in-vehicle information detection portion 7500 may also perform processing such as noise cancellation processing on a sound signal obtained by collection of sound.

The integrated control unit 7600 controls the overall operation within the vehicle control system 7000 according to various programs. The integrated control unit 7600 is connected to the input portion 7800. The input portion 7800 is realized by a device capable of an input operation by a passenger, such as a touch panel, a button, a microphone, a switch, a lever, or the like, for example. The integrated control unit 7600 can be supplied with data obtained by voice recognition of voice input via a microphone. The input portion 7800 may be a remote control device using infrared rays or other radio waves, for example, or an external connection device supporting the operation of the vehicle control system 7000, such as a mobile phone, a Personal Digital Assistant (PDA), or the like. The input portion 7800 may be, for example, a camera. In this case, the occupant can input information by a gesture. Alternatively, data obtained by detecting movement of a wearable device worn by the occupant may be input. Further, the input portion 7800 may include, for example, an input control circuit or the like that generates an input signal based on information input by an occupant or the like using the above-described input portion 7800, and outputs the generated input signal to the integrated control unit 7600. The occupant or the like inputs various data or gives instructions for processing operations to the vehicle control system 7000 through the operation input portion 7800.

The storage portion 7690 may include a Read Only Memory (ROM) that stores various programs executed by the microcomputer and a Random Access Memory (RAM) that stores various parameters, operation results, sensor values, and the like. In addition, the storage portion 7690 can be realized by a magnetic storage device such as a Hard Disk Drive (HDD), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like.

The general communication I/F7620 is a widely used communication I/F that mediates communication with various devices existing in the external environment 7750. The universal communication I/F7620 may implement a cellular communication protocol such as a global system for mobile communications (GSM (registered trademark)), worldwide interoperability for microwave access (WiMAX (registered trademark)), long term evolution (LTE (registered trademark)), LTE-advanced (LTE-a), etc., or another wireless communication protocol such as a wireless LAN (also referred to as wireless fidelity (Wi-Fi (registered trademark)), bluetooth (registered trademark), etc. the universal communication I/F7620 may be connected to a device (e.g., an application server or a control server) existing on an external network (e.g., the internet, a cloud network, or a company private network) via a base station or an access point, for example, and in addition, the universal communication I/F7620 may be connected to a terminal (e.g., a driver, a terminal) existing in the vicinity of the vehicle using a point-to-point (P2P) technology, for example, A terminal of a pedestrian or a shop, or a Machine Type Communication (MTC) terminal).

The dedicated communication I/F7630 is a communication I/F supporting a communication protocol developed for use in a vehicle. The dedicated communication I/F7630 may implement a standard protocol, such as, for example, Wireless Access (WAVE) in a vehicular environment, which is a combination of Institute of Electrical and Electronics Engineers (IEEE)802.11p as a lower layer and IEEE 1609 as a higher layer, Dedicated Short Range Communication (DSRC), or a cellular communication protocol. The dedicated communication I/F7630 generally performs V2X communication, the concept of which includes one or more of vehicle-to-vehicle communication (vehicle-to-vehicle), road-to-vehicle communication (vehicle-to-infrastructure), vehicle-to-home communication (vehicle-to-home), and pedestrian-to-vehicle communication (vehicle-to-pedestrian).

For example, the positioning portion 7640 performs positioning by receiving Global Navigation Satellite System (GNSS) signals from GNSS satellites (for example, GPS signals from Global Positioning System (GPS) satellites), and generates position information including latitude, longitude, and altitude of the vehicle. Incidentally, the positioning portion 7640 may recognize the current position by exchanging signals with a wireless access point, or may obtain position information from a terminal such as a mobile phone, a Personal Handyphone System (PHS), or a smart phone having a positioning function.

The beacon receiving section 7650 receives, for example, radio waves or electromagnetic waves transmitted from a radio station installed on a road or the like, thereby obtaining information on the current position, congestion, closed road, necessary time, and the like. Incidentally, the function of the beacon reception section 7650 may be included in the dedicated communication I/F7630 described above.

The in-vehicle device I/F7660 is a communication interface that mediates a connection between the microcomputer 7610 and various in-vehicle devices 7760 existing in the vehicle. The in-vehicle device I/F7660 can establish a wireless connection using a wireless communication protocol such as wireless LAN, bluetooth (registered trademark), Near Field Communication (NFC), or Wireless Universal Serial Bus (WUSB). In addition, the in-vehicle apparatus I/F7660 may establish a wired connection via a connection terminal (and a cable as necessary) not shown in the drawings through a Universal Serial Bus (USB), a high-definition multimedia interface (HDMI (registered trademark)), a mobile high-definition link (MHL), or the like. The in-vehicle device 7760 may include, for example, at least one of a mobile device and a wearable device owned by an occupant and an information device carried into or attached to the vehicle. The in-vehicle device 7760 may further include a navigation device that searches for a route to an arbitrary destination. The in-vehicle device I/F7660 exchanges control signals or data signals with these in-vehicle devices 7760.

The in-vehicle network I/F7680 is an interface as a communication medium between the microcomputer 7610 and the communication network 7010. The in-vehicle network I/F7680 transmits and receives signals and the like in accordance with a predetermined protocol supported by the communication network 7010.

The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 according to various programs based on information obtained via at least one of the general-purpose communication I/F7620, the special-purpose communication I/F7630, the positioning section 7640, the beacon receiving section 7650, the in-vehicle apparatus I/F7660, and the in-vehicle network I/F7680. For example, the microcomputer 7610 may calculate a control target value for the driving force generation device, the steering mechanism, or the brake device based on the obtained information on the inside and outside of the vehicle, and output a control command to the drive system control unit 7100. For example, the microcomputer 7610 may execute cooperative control aimed at realizing functions of an Advanced Driver Assistance System (ADAS) including collision avoidance or impact mitigation of the vehicle, following driving based on a following distance, vehicle speed maintaining driving, warning of a vehicle collision, warning of a vehicle lane departure, and the like. In addition, the microcomputer 7610 can execute cooperative control intended for automatic driving by controlling the driving force generation device, the steering mechanism, the brake device, and the like, based on the obtained information about the surroundings of the vehicle, which allows the vehicle to travel autonomously without depending on the operation of the driver, and the like.

The microcomputer 7610 may generate three-dimensional distance information between the vehicle and an object such as a surrounding structure, a person, or the like, based on information obtained via at least one of the general communication I/F7620, the special communication I/F7630, the positioning portion 7640, the beacon receiving portion 7650, the in-vehicle apparatus I/F7660, and the in-vehicle network I/F7680, and generate local map information including information on a surrounding environment of a current location of the vehicle. In addition, the microcomputer 7610 can predict a danger such as a collision of a vehicle, an approach of a pedestrian or the like, an entrance into a closed road, or the like, based on the obtained information, and generate a warning signal. The warning signal may be, for example, a signal for generating a warning sound or illuminating a warning lamp.

The sound/image output portion 7670 transmits an output signal of at least one of a sound and an image to an output device capable of visually or audibly notifying information to an occupant of the vehicle or the outside of the vehicle. In the example of fig. 23, as the output devices, an audio speaker 7710, a display portion 7720, and a dashboard 7730 are illustrated. The display portion 7720 may, for example, include at least one of an on-board display and a flat-view display. The display portion 7720 may have an Augmented Reality (AR) display function. The output device may be a device other than these devices, and may be another device such as an earphone, a wearable device such as a glasses-type display worn by a passenger or the like, a projector, a lamp, or the like. In the case where the output device is a display device, the display device visually displays results obtained by various processes performed by the microcomputer 7610 or information received from another control unit in various forms such as text, images, tables, charts, and the like. In addition, in the case where the output device is an audio output device, the audio output device converts an audio signal composed of reproduced audio data, sound data, or the like into an analog signal, and outputs the analog signal acoustically.

Incidentally, in the example shown in fig. 23, at least two control units connected to each other via the communication network 7010 may be integrated into one control unit. Alternatively, each individual control unit may comprise a plurality of control units. Furthermore, the vehicle control system 7000 may comprise a further control unit, which is not shown in the figure. In addition, some or all of the functions performed by one of the above-described control units may be distributed to another control unit. That is, as long as information is transmitted and received via the communication network 7010, predetermined arithmetic processing may be performed by any control unit. Similarly, a sensor or a device connected to one of the control units may be connected to another control unit, and a plurality of the control units may transmit and receive detection information to and from each other via the communication network 7010.

In the vehicle control system 7000 described above, the variable focal length lens system and the imaging apparatus of the present disclosure are applicable to the imaging section 7410 and any of the

imaging sections

7910, 7912, 7914, 7916, and 7918.

[ 6] other embodiments ]

The technique of the present invention is not limited to the above-described embodiments and examples, and various modifications can be made.

For example, the shape and the value of each part described in the above numerical example are each merely examples of implementation of the present technology, and the technical scope of the present technology should not be construed as being limited by these examples.

Further, in the above embodiments and implementation examples, the configuration basically including four lens units has been described; however, a configuration may be provided that further includes a lens having substantially no optical power.

Further, for example, the present technology may be provided with the following configuration. According to the present technology having the following configuration, four lens units are included as a whole, and the configuration of each lens unit is optimized by appropriately using a free-form surface. Therefore, good image forming performance from the wide-angle end state to the telephoto end state can be achieved with a small number of lenses.

(1)

A variable focal length lens system comprising, in order from an object side to an image plane side:

a first lens unit including a rotationally symmetric shaped lens;

a second lens unit including a first free-form-surface lens in which at least one lens surface is a free-form surface;

a third lens unit including a second free-form-surface lens in which at least one lens surface is a free-form surface; and

a fourth lens unit having an aperture stop and including a lens of a rotationally symmetric shape, wherein

The first lens unit is coaxial with the fourth lens unit, and,

wherein a Z-axis is an optical axis of the fourth lens unit, a Y-axis is an axis orthogonal to the Z-axis on the image plane, and an X-axis is an axis orthogonal to the Y-axis and the Z-axis on the image plane,

the second lens unit and the third lens unit are movable in the Y-axis direction, and by moving in directions opposite to each other, so that the combined refractive power of the second lens unit and the third lens unit is variable, and the fourth lens unit is moved in the optical axis direction so that variation in the image plane position with variation in the combined refractive power is compensated for.

(2)

The variable focal length lens system according to (1), wherein the following conditional expression is also satisfied,

wherein

Is the refractive power of the first free-form-surface lens in the X-axis direction in the wide-angle end state,

is a refractive power of the second free-form-surface lens in the X-axis direction in the wide-angle end state, and fw is a total focal length of the lens system in the wide-angle end state.

(3)

The variable focal length lens system according to (1) or (2), wherein the following conditional expression is also satisfied,

wherein,

is the refractive power of the first free-form-surface lens in the X-axis direction in the telephoto end state,

is the refractive power of the second free-form surface lens in the X-axis direction in the telephoto end state, and ft is the power in the telephoto end stateThe total focal length of the lens system in this state.

(4)

The variable focal length lens system according to any one of (1) to (3), wherein the following conditional expression is also satisfied,

wherein,

is a combined refractive power in the X-axis direction of the first free-form-surface lens and the second free-form-surface lens in the wide-angle end state,

is a combined refractive power in the Y-axis direction of the first free-form-surface lens and the second free-form-surface lens in the wide-angle end state,

is a combined refractive power of the first free-form-surface lens and the second free-form-surface lens in the X-axis direction in the telephoto end state,

is a combined refractive power in the Y-axis direction of the first and second free-form-surface lenses in the wide-angle end state, fw is a total focal length of the lens system in the wide-angle end state, and ft is a total focal length of the lens system in the telephoto end state.

(5)

The variable focal length lens system according to any one of (1) to (4),

when the object distance is moved from the infinity position to the close point, the fourth lens unit is moved in the optical axis direction, and

the following conditional expression is also satisfied,

wherein,

is a combined refractive power in the X-axis direction of the first and second free-form-surface lenses in the telephoto end state, and

is a combined refractive power of the first free-form-surface lens and the second free-form-surface lens in the Y-axis direction in the telephoto end state.

(6)

The variable focal length lens system according to any one of (1) to (5), wherein the following conditional expression is also satisfied,

1.2＜Δ2/ft＜2.5……(9)

0.8＜Δ3/ft＜1.6……(10)

where Δ 2 is a moving distance of the second lens unit in the Y-axis direction when the lens position state changes from the wide-angle end state to the telephoto end state, Δ 3 is a moving distance of the third lens unit in the Y-axis direction when the lens position state changes from the wide-angle end state to the telephoto end state, and ft is a total focal length of the lens system in the telephoto end state.

(7)

The variable focal length lens system according to any one of (1) to (7), wherein the first lens unit includes a positive lens and at least one negative lens, the positive lens being disposed closer to the image plane side than the negative lens.

(8)

An image forming apparatus comprising:

a variable focal length lens system; and

an imaging device that outputs an imaging signal based on an optical image formed by the variable focal length lens system,

a variable focal length lens system includes, in order from an object side to an image plane side,

a first lens unit including a lens of a rotationally symmetric shape,

a second lens unit including a first free-form-surface lens in which at least one lens surface is a free-form surface,

a third lens unit including a second free-form-surface lens in which at least one lens surface is a free-form surface, an

The first lens unit is coaxial with the fourth lens unit, and,

(9)

The variable focal length lens system according to any one of the above (1) to (7), further comprising a lens having substantially no refractive power.

(10)

The imaging apparatus according to the above (8), wherein the variable focal length lens system further includes a lens having substantially no refractive power.

This application claims priority from japanese patent application No.2017-201276, filed by the japanese patent office on 2017, 10, 17, the entire contents of which are incorporated herein by reference.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may be made in accordance with design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A variable focal length lens system comprising, in order from an object side to an image plane side:

a first lens unit including a rotationally symmetric shaped lens;

The first lens unit is coaxial with the fourth lens unit, and,

2. The variable focus lens system of claim 1, wherein the following conditional expression is further satisfied,

wherein

3. The variable focus lens system of claim 1, wherein the following conditional expression is further satisfied,

wherein,

is the refractive power of the second free-form-surface lens in the X-axis direction in the telephoto end state, and ft is the total focal length of the lens system in the telephoto end state.

4. The variable focus lens system of claim 1, wherein the following conditional expression is further satisfied,

wherein,

5. The variable focus lens system of claim 1,

the following conditional expression is also satisfied,

wherein,

6. The variable focus lens system of claim 1, wherein the following conditional expression is further satisfied,

1.2＜Δ2/ft＜2.5……(9)

0.8＜Δ3/ft＜1.6……(10)

7. The variable focus lens system of claim 1, wherein the first lens unit comprises a positive lens and at least one negative lens, the positive lens being disposed closer to the image plane side than the negative lens.

8. An image forming apparatus comprising:

a variable focal length lens system; and

a first lens unit including a lens of a rotationally symmetric shape,

The first lens unit is coaxial with the fourth lens unit, and,