JP2003156672A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manually perform flange back adjustment and macro operation in a zoom lens performing automatic focus control by the driving of a wobbling lens. SOLUTION: A housing to which a motor for driving the wobbling lens is attached is constituted to move in the optical axis direction, and the wobbling lens is moved together with the driving motor through a cam from the outside of the zoom lens.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device,
In particular, it is suitable for a television camera or a video camera with respect to the improvement of the focus adjustment mechanism of the zoom lens having the automatic focus detection means.

[0002]

2. Description of the Related Art A flange back adjustment of a zoom lens system is carried out by using a wobbling lens (having almost the same movement as the second focus lens of the present invention) which is detachable from an image pickup device and has an automatic focus detecting means. FIG. 5 shows a conventional zoom lens structure to be used.

In the figure, reference numeral 101 is a focus lens group, and 102 is a variable power lens group for correcting a lens group 102a which moves on the optical axis to perform variable power and an image plane which varies with variable power. Lens group 102b. 1
Reference numeral 03 is a diaphragm device for adjusting the amount of light, 104 is a relay lens, and 105 is a variable-magnification optical system (extender lens) arranged so that it can be inserted into and removed from the optical path, and changes the focal length range of the entire zoom lens system. Have an effect. A movable lens group 106 adjusts the back focus (flange back) of the entire system when the extender lens group 105 is arranged in the optical path. Reference numeral 107 is a rear group relay lens, and 108 is a lens group (wobbling lens) that is finely driven in the optical axis direction. In the figure, each of the above elements 101 to
A zoom lens 108 is formed.

Reference numeral 109 is an image sensor, and 110 is a video signal processing circuit, which obtains a video signal based on a signal from the image sensor 109. 111 is a focus lens group 101
A focus lens group drive unit for electrically driving the
Reference numeral 112 is a drive unit for electrically driving the variable power lens group 102, 113 is a drive unit for electrically driving the diaphragm 103, 114 is a detection device for detecting insertion / removal of the extender, and 115 is a first unit. A drive unit for electrically driving the second focus lens 108, 116 is an arithmetic unit, 1
Reference numeral 17 is a recording unit.

Further, FIG. 6 shows a sectional view in the optical axis direction of the detailed structure of the drive mechanism 115 for the wobbling lens 108. The wobbling lens 108 is fixed to a holding frame 119, and the holding frame 119 has a plurality of guide bars 120 rigidly supported by a lens housing 118 by fitting holes so as to prevent the wobbling lens 108 from falling.
It is held slidably only in the optical axis direction by (only one is shown in the figure). The holding frame 119 is the lens housing 1
A feed screw 122 held by a bearing 18 is connected to a connecting member 121. The feed screw 122 is directly connected to a drive motor 123, and the feed screw 122 is rotated by rotating the drive motor 123 based on a drive signal returned from the arithmetic unit 116,
By moving the connecting member 121, the wobbling lens 108 is moved in the optical axis direction.

Conventionally, in an image pickup apparatus for performing focusing control using this type of automatic detection apparatus, flange back correction is performed using a wobbling lens mechanism. Specifically, in a zoom lens proposed in Japanese Patent Application Laid-Open No. 9-43503, a gap between a flange back in a state in which the extender is not inserted and a flange back in the case in which the extender is inserted is displaced. (Shift amount) is stored, and the deviation of the flange back is corrected based on the calculated value using a wobbling lens, or the zoom lens proposed in Japanese Patent Laid-Open No. 11-127376 is mounted on a video camera or the like. When the power was turned on, it was used as a means for automatically adjusting the flange back of the zoom lens system that uses a wobbling lens as part of the initialization flow of the electrical setting values.
All of these are premised on being accompanied by electric drive.

[0007]

If the wobbling lens (second focus lens) mechanism as described above is used for purposes other than the automatic focus detection of the image pickup apparatus, there are the following problems. Generally, this kind of zoom lens
It is often used in a harsh environment such as below freezing, and at this time the power capacity allocated to the entire imaging device may be limited, and it is automatically performed without knowing when the power will be cut off. In many cases, the photographer intentionally does not perform automatic focus detection in order to select a stable photographing method rather than a photographing method using focus detection.

At this time, the back focus (flange back) of the zoom lens system using the second focus lens
Adjustment is possible only by electrical drive,
There is no way to do everything manually. Furthermore, in an emergency such as when the power to the zoom lens is cut off, a known zoom lens without an automatic focus detection device can be used for shooting without any problem, whereas this may occur during automatic focus detection control. In such an emergency, the second focus lens may not be returned to the position where the flange back displacement is corrected, and there is no means for correcting this displacement, so the subject is not captured in the subsequent shooting. There will be a situation where the focus cannot be adjusted to.

Also, when the photographer takes a picture without using the automatic focus detection control from the beginning, similarly, the flange back cannot be adjusted.

The object of the present invention is to solve the above-mentioned problems,
Another object of the present invention is to provide a second focus lens drive mechanism built-in zoom lens which can be used comfortably in any environment.

[0011]

An image pickup apparatus according to the present invention for solving the above-mentioned problems takes an image by a zoom lens having a first focus lens group, an aperture stop, and an extender lens which can be inserted into and removed from an optical path. In an image pickup apparatus for forming an object image on the surface of the means, an electric drive and the same operation as the electric drive are performed on the drive means of the second focus lens constituting the zoom lens, which is equivalent to a known zoom lens. It has a feature that it has a structure including a manual operation part that can be performed in step 1 and a manual operation transmission mechanism.

[0012]

1 is a schematic view of a zoom lens system in which a second focus lens driving mechanism according to an embodiment of the present invention is incorporated. FIG. 2 is a simple sectional view of the second focus lens drive mechanism in the optical axis direction.

The structure of the entire zoom lens system for performing the focusing operation by the automatic focus detection according to the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 is a first focus lens group. The first focus lens group 1 is driven on the optical axis by the first focus lens drive unit 11, and thereby the focusing operation is performed. Reference numeral 2 denotes a variable power lens group, which is composed of a lens group 2a that moves on the optical axis to perform variable power, and a lens group 2b that corrects an image plane that changes due to variable power. Reference numeral 3 is an aperture stop. Reference numeral 4 is a front group relay lens. Reference numeral 5 denotes a variable power optical system (extender lens) arranged in the optical path so as to be removable, and changes the focal length range of the entire zoom lens system. A movable lens group 6 constitutes a part of the extender lens 5, and is used for adjusting the back focus (flange back) of the entire zoom lens system when the extender lens 5 is arranged in the optical path. Reference numeral 7 is a fixed rear group relay lens. Reference numeral 8 denotes a lens group (second focus lens) that is driven in the optical axis direction, and is moved in the optical axis direction by an electric drive unit 15 or a manual drive unit 18, which will be described later in detail.

In the present embodiment, each of the elements 1 to 8 constitutes a zoom lens. Reference numeral 9 is an image sensor, and 10 is a video signal processing circuit, which obtains a video signal based on a signal from the image sensor 9. 11 is the first focus lens group 1
For driving the variable power lens group 2, 13 for driving the aperture stop 3, 14 for extender detection means,
Reference numeral 15 is an electric drive unit for electrically driving the second focus lens 8, and 16 is a calculation unit, which performs calculation for controlling various types of drive of the entire zoom lens. 1
Reference numeral 7 denotes a recording unit, which is used for recording the shift amount of the origin position of the second focus lens for correcting the change in the shift amount of the flange back when the extender is inserted into and removed from the optical path. ing. Reference numeral 18 denotes a manual operation unit for manually operating the second focus lens 8, which has a configuration in which both manual and electric operation can be performed according to an operator's shooting situation.

In the present invention, the second focus lens 8
Is based on the data output from the calculation unit 16, mainly using a signal obtained by the image pickup unit 9 when the second focus lens 8 is slightly moved back and forth in the optical axis direction. It is used for control of moving the focus lens group 8 to perform automatic focus detection. Further, the first force lens group 1 is fixed at an arbitrary position within the operation range during the automatic focus detection operation (in many cases, an infinite end).

Next, the mechanism of the electric drive section 15 and the manual drive section 18 of the second focus lens 8 according to the present invention will be described in detail with reference to FIG.

The second focus lens 8 is fixed to a holding frame 21 that holds the second focus lens, and the holding frame 21 prevents deterioration of optical performance due to tilting of the second focus lens 8. Further, a plurality of guide bars 22 (only one in the figure) rigidly supported by the zoom lens housing 19 are slidably supported by fitting holes in the optical axis direction.

The holding frame 21 is connected to a feed screw 24 rotatably supported by the movable casing 20 by a connecting portion 23. The feed screw 24 is directly connected to a drive motor 25, and the drive motor 25 rotates the feed screw 24 based on a drive signal returned from the arithmetic unit 16 so that the light of the second focus lens 8 is emitted. Driven in the axial direction.

The movable casing 20 is slidably supported in the optical axis direction by a plurality of guide bars 22 (only one is shown in the figure) rigidly supported by the zoom lens casing 19 through fitting holes. ing. Reference numeral 26 is attached to the movable housing 20, and the rotation of the flange back ring 27 and the macro ring 29 by a manual operation drives the movable housing 20 in the optical axis direction from a cam 29a provided on the inner diameter of the macro ring 29. The interlocking pin for transmitting the force for supporting the flange back ring 2
It is a stopper for stopping the rotation of 7, and when adjusting the flange back manually, loosen the stopper 28 and operate the flange back ring 27. Thirty
Is a macro pin for fixing the macro ring 29 to the flange back ring 27 in the rotational direction. When performing manual macro photography, the macro pin 30 is removed from the flange back ring 27.

Here, in the case where the operator manually shoots without using the automatic focus detection, or when the operator is forced to shoot in a state in which power is not supplied to the zoom lens from the video camera body or another power supply. , Operator is second
When the focus lens 8 is operated to perform flange back adjustment and the like or macro photography, the operator loosens the stopper 28 and the macro pin 30 and then operates the flange back ring 27 and the macro ring 29. The second focus lens 8 can be driven manually only by itself. At this time, the movement amount A of the second focus lens 8 by the electric drive shown in FIG. 3 and the operation amount A ′ of the second focus lens 8 by the manual drive shown in FIG. Since A = A ', the same image can be obtained on the image pickup device 9.

[0021]

As described above, the image pickup apparatus according to the present invention is a known zoom lens system in which the operator does not perform automatic focus detection even when the operator does not electrically drive the zoom lens for automatic focus detection. This makes it possible to shoot with the same work as the lens.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a cross section of a main part of a product using an embodiment in an optical axis direction.

FIG. 2 is a cross-sectional view of the essential parts of the detailed mechanism of the present invention in FIG.

FIG. 3 is a cross-sectional view of the present invention during electric driving.

FIG. 4 is a sectional view of the present invention during manual driving.

FIG. 5 is a configuration diagram showing a cross section of a main part of a conventional product in the optical axis direction.

FIG. 6 is a cross-sectional view of an extracted essential part of a conventional mechanism for the present invention.

[Explanation of symbols]

1, 101 (first) focus lens group 2, 102 variable power lens group 2a, 102a variable power lens group 2b, 102b image plane correction lens group 3, 103 aperture stop device 4, 104 front lens group relay lens group 5, 105 Extender lens group 6,106 Movable lens group 7,108 Rear group relay lens group 8,108 Second focus lens (wobbling lens) 9,109 Image sensor 10,110 Video signal processing circuit 11,111 (First) focus Lens group driving device 12,112 Variable magnification lens group driving device 13,113 Aperture driving part 14,114 Extender switching detection part 15,115 Second focus lens (wobbling lens) electric driving part 16,116 Arithmetic device 17,117 Recording Section 18 Second focus lens manual drive section 19, 118 Lens housing 20 Movable housing 21,119 Second focus lens (wobbling lens) holding frame 22,120 Guide bar 23,121 Connecting member 24,122 Feed screw 25,123 Electric drive motor 26 Interlocking pin 27 Flange back ring 28 Stopper 29 Macro ring 29a Movable housing drive cam 30 Macro pin

Front page continuation (51) Int.Cl. ⁷ identification code FI theme code (reference) G02B 7/28 G02B 7/11 K G03B 13/36 G03B 3/00 A H04N 5/225 G02B 7/04 A F term ( Reference) 2H011 AA03 BA31 CA16 CA18 CA21 2H044 BE02 BE11 DA01 DB01 DB02 DE01 2H051 AA08 BA41 BA60 CD16 FA30 FA33 FA63 FA70 FA71 5C022 AB23 AB66 AC42 AC54 AC74

Claims (2)

[Claims] 1. A first focus lens group for focus adjustment, a zoom lens group whose position is driven along the optical axis for zooming, and a zoom lens group behind the zoom lens group. An image pickup apparatus for forming an object image on a surface of an image pickup means by a zoom lens group having a second focus lens group for performing focus adjustment using a signal obtained by the image pickup means when moved along an axis, Electric drive means for electrically driving the second focus lens group;
It has a manual drive means for manually operating the second focus lens group from the outside of the image pickup device, and when the second focus lens group is manually operated, an electric drive means for the second focus lens group and An image pickup apparatus, wherein the second focus lens group moves integrally in the optical axis direction. 2. The second focus lens group can perform not only focus adjustment but also flange back adjustment and macro photography by driving in the optical axis direction, and manual operation of the second focus lens group is not possible. The image pickup apparatus according to claim 1, wherein the image pickup apparatus can be operated by the same operation as a known image pickup apparatus.