JP2003222783A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which uses a wobbling lens for photographing by an automatic focus detection and is composed of zoom lenses in which an adjustment of a flange back is implemented by the wobbling lens and which is equipped with a wobbling drive mechanism used without detriment to operational capability of lenses even at an emergency in which a photographer falls when power supply is cut off and electrical drive of zoom lenses can not be effected. <P>SOLUTION: The device is of the configuration that a gear is laid at an end of a feed screw which composes a part of an electric drive mechanism of the wobbling lens and an operating part capable of rotating the wobbling lens at a predetermined speed is laid through a power transmission mechanism capable of switching an action arbitrarily and is usually covered with a guard frame. The guard is moved when an operator so desires and the power transmission mechanism and the operating part are connected, thereby enabling the wobbling lens to be driven manually. <P>COPYRIGHT: (C)2003,JPO

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 conventional zoom lens structure which is detachable from an image pickup apparatus, has an automatic focus detection means, and adjusts a flange back of a zoom lens system by using a wobbling lens is a special application as a prior application. Kaihei 9-4350
No. 3, JP-A-9-197261 or JP-A No. 11-127376, the structure of the zoom lens disclosed in JP-A No. 9-43503 is used as a conventional example. I will explain. The structure of the zoom lens in that case is shown in FIG.

In the figure, reference numeral 101 is a focusing 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 surface which varies with variable power. Lens group 102b. Reference numeral 103 is a diaphragm device for adjusting the amount of light, 104 is a lens group (wobbling lens) that is minutely driven in the optical axis direction, 105 is a relay lens, and 106 is a variable-magnification optical system (extender) that is removably arranged on the optical path. Lens), and has the effect of shifting the focal length range of the entire zoom lens system to the long focus side. A movable lens group 107 constitutes a part of the extender lens 106, and adjusts the back focus (flange back) of the entire system when the extender lens 106 is arranged in the optical path. 10
8 is a rear group relay lens. In the same figure, a zoom lens is constituted by the above-mentioned respective elements 101 to 108.

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. Reference numeral 111 denotes a focus lens group drive unit for electrically driving the focus lens group 101, 11
Reference numeral 2 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 drive unit for electrically driving the wobbling lens 104, Reference numeral 115 is a detection device for detecting insertion / removal of the extender, 116 is a calculation device, and 117 is a recording unit.

Further, FIGS. 7 and 8 show the detailed structure of the drive mechanism 114 of the wobbling lens 104.
FIG. 7 shows a cross-sectional configuration diagram in the optical axis direction, and FIG. 8 shows a view from the image sensor side. The wobbling lens 104 is a holding frame 1.
The holding frame 118 is fixed to the holding frame 118 at the positions of the fitting hole 118a and the fitting groove 118b provided in the holding frame 118 so as to prevent the wobbling lens 104 from falling.
A plurality of guide bars 119 (only one is shown in the figure) rigidly supported by a lens housing (not shown) are slidably held in the optical axis direction. The holding frame 118 is connected by a connecting member 122 to a feed screw 121 whose front and rear are held by bearings 120. The feed screw 121 is directly connected to a drive motor 123, and the feed screw 121 is rotated by the drive motor 123 based on a drive signal returned from the arithmetic unit 116 to drive the wobbling lens 104 in the optical axis direction. Is going.

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. More specifically, in a zoom lens provided with an insertable / retractable extender proposed in Japanese Patent Laid-Open No. 9-43503, there is a deviation between a flange back in which the extender is not inserted and a flange back in which the extender is inserted. (Shift amount)
And a correction means for matching the deviation of the flange back using a wobbling lens based on the recorded value, and the zoom lens attached to a video camera or the like proposed in JP-A-11-127376. When it 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 electrical settings.
Basically, all of the conventionally proposed wobbling lens mechanism systems are premised on electrically driving.

[0007]

If the wobbling 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. In general, this type of zoom lens is often used in harsh environments such as outdoors below freezing,
At this time, the power capacity allocated to the entire imaging device may be limited, so a stable shooting method should be selected over the shooting method using automatic focus detection, which does not know when the power supply will be cut off. In addition, the photographer often chooses not to intentionally perform automatic focus detection.

At this time, since the back focus (flange back) adjustment of the zoom lens system using the wobbling lens can be performed only by electric driving, there is no way to perform all manually. Furthermore, in an emergency when the power supply 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, but such a situation occurs during automatic focus detection control. In an emergency, the wobbling lens does not return to the position where the flange back shift is corrected, and there is no means to correct this shift. There is a situation in which the

The object of the present invention is to solve the above problems,
It is an object of the present invention to provide a zoom lens with a built-in wobbling lens that can be used in a required minimum amount in any usage environment.

[0010]

(1) An image pickup apparatus according to the present invention for solving the above-mentioned object has a zoom lens having a focus lens group, an aperture stop, and an extender lens that is removably mounted in the optical path. Thus, in an image pickup apparatus for forming an object image on the surface of an image pickup means, an operating member for driving the wobbling lens by a predetermined operation amount is manually added to a driving means of the wobbling lens forming the zoom lens. It has a feature of having a structure including an operation transmission mechanism.

(2) In an image pickup apparatus for forming an object image on the surface of an image pickup means by a zoom lens having a focus lens group, a variable power lens group, and an extender lens which is removably mounted in the optical path, the zoom is performed. The transmission mechanism, which is configured as an electric drive unit of the wobbling lens that constitutes the lens, is characterized by having a structure capable of switching the connection with the manually operated operation member.

The present invention will be described in detail based on the illustrated embodiment.

[0013]

1 is a schematic view of a zoom lens system incorporating a wobbling lens mechanism according to an embodiment of the present invention. 2 is a cross-sectional view of a main part of the wobbling mechanism in the optical axis direction (however, the transmission mechanism is rearranged for easy visual recognition), and FIG. 3 is a view from the rear of FIG.

First, the configuration of the entire zoom lens system for performing a focusing operation by automatic focus detection according to the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a focusing lens group. The focusing lens group 1 includes a focusing lens driving unit 1 based on a focusing signal from the calculation unit 17.
It is driven on the optical axis by 1, and a focusing operation is performed by this. 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 the image plane that changes with variable power. Reference numeral 3 is an aperture stop. Reference numeral 4 denotes a lens group (wobbling lens) that is minutely driven in the optical axis direction, and is moved in the optical axis direction by an electric drive unit 14 or a manual drive unit 18 which will be described later in detail.

In this embodiment, the wobbling lens 4 is used.
Mainly uses a signal obtained by the image pickup means 9 when the wobbling lens 4 is moved in the optical axis direction.
Reference numeral 6 is used to obtain the moving direction of the focusing lens group 1 and input it to the driving unit 11, and the driving unit 11 moves the focusing lens group 1 to perform automatic focus detection, while the wobbling lens 4 is used. It is used to adjust the flange back of the entire zoom lens system (correction of deviation when inserting an extender lens of equal magnification and arbitrary magnification).

Reference numeral 5 denotes a fixed front lens group relay lens during zooming. Reference numeral 6 denotes a variable power optical system (extender lens) arranged in the optical path so that it can be inserted and removed, and shifts the focal length range of the entire zoom lens system to the long focus side. A movable lens group 7 constitutes a part of the extender lens 6 and is used for adjusting the back focus (flange back) of the entire zoom lens system when the extender lens 6 is arranged in the optical path. 8 is a rear group relay lens.

In this 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 a drive unit for moving the focus lens group 1 in the optical axis direction, 12 is a drive unit for driving the variable power lens group 2, 13 is a drive unit for driving the diaphragm 3, and 14 is a wobbling lens. An electric drive unit for electrically driving 4 (detailed configuration will be described later in detail), and 15 is an extender detection unit for detecting an insertion / removal state in the optical path of the extender lens 6. Reference numeral 16 denotes a calculation unit, which performs calculation for controlling various types of drive of the entire zoom lens. Reference numeral 17 denotes a recording unit, for correcting a change in the shift amount of the flange back at the same magnification when the extender is inserted into and removed from the optical path,
It is used to record the shift amount of the origin position of the wobbling lens.

The electric drive unit 14 is provided with a manual drive unit 18 which constitutes a manual drive mechanism, which will be described in detail later, so that both drive systems can be switched according to the photographing situation of the operator. .

Next, the mechanism of the electric drive unit 14 and the manual drive unit 18 of the wobbling lens 4 according to the present invention will be described in detail with reference to FIGS.

As shown in FIGS. 2 and 3, the wobbling lens 4 is fixed to a holding frame 19 that holds the wobbling lens 4, and the holding frame 19 deteriorates in optical performance due to the wobbling lens 4 tilting. So as to prevent the fitting hole 19a and the fitting groove 19b provided in the holding frame 19.
In this position, a plurality of guide bars 20 (only one is shown in the figure) rigidly supported by a zoom lens housing (not shown) are slidably supported in the optical axis direction.

The holding frame 19 has front and rear bearings 21.
The feed screw 22 gripped by is connected to the connecting member 23. The feed screw 22 is directly connected to a drive motor 24, and the drive motor 24 rotates the feed screw 22 based on a drive signal returned from the arithmetic unit 16, so that the wobbling lens 4 is moved in the optical axis direction. It is driving.

A gear 26 is fixed by a fixing screw 25 to the opposite end of the feed screw 22 which is directly connected to the drive motor 24. The gear 26 includes a transmission mechanism (gear train) 27 set to a predetermined reduction ratio.
a and 27b are respectively supported by shafts 28a and 28b rigidly supported by a lens housing (not shown).

The gear 27 which is the transmission mechanism 27
At b, a knob 30 constituting a spring 29 loaded so that a force is applied in a direction away from the transmission mechanism 27 is fixed to a shaft 31 rigidly supported by a zoom lens housing (not shown).

Here, the essential parts of the zoom lens including the electric drive unit 14 for the wobbling lens and the manual drive unit 18 (particularly in the vicinity of the knob 30) are shown in FIGS.
FIGS. 5a and 5 show configurations of the wobbling lens electric drive unit 14 and the manual drive unit 18 in the states of FIGS.
Shown in b. As shown in FIG. 4 a, the wobbling lens electric drive unit 14 and the manual drive unit 18 are externally provided with a box portion 32.
It is housed inside, and has a structure that the operator does not touch it carelessly during normal use. Further, as shown in FIGS. 4b and 4c, the knob 30 can be touched by opening a protective lid 33 that can be opened and closed by a hinge (not shown).

As shown in FIGS. 4b and 5a, the knob 3
0 is the transmission mechanism (gear) 2 by the spring 29 in a normal use state as a lens for automatic focus detection.
It is always charged in a positional relationship where it does not come into contact with 7b, and even if the operator operates the knob 30 by mistake,
Manual power is not transmitted to the feed screw 22,
It has a structure that does not cause damage or malfunction of the mechanical system.

Here, in an emergency case where the power is not supplied to the zoom lens from the main body of the video camera or another power source, the operator operates the wobbling lens 4 to perform a correction operation such as a flange back adjustment. 4b, first, the protective lid 33 is opened so that the knob 30 can be operated, as shown in FIG. 4b. Next, FIG.
As shown in FIG. 5c and FIG. 5b, the knob 30 is slid in the direction of the transmission mechanism 27 (the gear 27b in the figure) (the operation direction is clearly shown at a position visible to the operator during operation). 30 and the transmission mechanism 27 are connected,
It is possible to drive the feed screw 22 via the transmission mechanism 27. The wobbling lens 4 can be manually operated by this mechanism.

With the mechanism described above, a wobbling lens that adjusts the flange back of the zoom lens even when the photographer encounters an emergency situation in which all the electric drive of the zoom lens for automatic focus detection is impossible. By adopting a structure that can be driven manually, focus manual operation which is the minimum necessary operation of the zoom lens,
In addition to manual zoom operation and manual aperture operation, flange back manual adjustment is also possible, and the zoom lens can be used for photographing purposes.

[0029]

As described above, in the image pickup apparatus according to the present invention, in the zoom lens used mainly for the purpose of photographing by the automatic focus detection, the flange back correction is also performed by operating the built-in wobbling lens. Even if the photographer falls into a situation in which the electric power cannot be supplied to the zoom lens for some reason and all the electric drive cannot be performed, by providing an operation unit capable of manually operating the wobbling lens, Makes it possible to perform a shooting action by using the original role of the zoom 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 rear view of FIG.

FIG. 4a is a main part of an external view of a product using the present embodiment.

FIG. 4b is an external view when a part of the components is moved in FIG. 4a.

FIG. 4c is an external view when a part of the components shown in FIG. 4b is activated.

5a is a cross-sectional development view of the main part of the present embodiment inside FIG.

FIG. 5b is a sectional development view when a part of the mechanism in FIG. 5a is activated.

FIG. 6 is a configuration diagram showing a cross section of a main part of a conventional product in the optical axis direction.

FIG. 7 is a sectional view showing a main part of a conventional mechanism for the present invention.

FIG. 8 is a rear view of FIG.

[Explanation of symbols]

1,101 Focusing lens group 2,102 variable power lens group 2a, 102a variable power lens group 2b, 102b Image plane correction lens group 3,103 diaphragm device 4,104 wobbling lens 5,105 Front group relay lens group 6,106 extender lens group 7,107 Movable lens group 8,108 Rear lens group 9,109 Image sensor 10,110 Video signal processing circuit 11,111 Focus lens group drive unit 12,112 Variable magnification lens group drive unit 13,113 Aperture drive unit 14,114 Wobbling lens electric drive 15,115 Extender switching detector 16,116 arithmetic unit 17,117 recording section 18 Wobbling lens manual drive 19 Wobbling lens holding frame 20 Guide bar 21 bearing 22 Lead screw 23 Connection member 24 Electric drive motor 25 fixing screw 26 gears 27a, 27b Transmission mechanism 28a, 28b axis 29 spring 30 knob 31 axis 32 case box 33 Protective lid

Continued front page    F-term (reference) 2H044 DA00 DA01 DA02 DB01 DB02                       DB08 EC01                 5C022 AB23 AB26 AB44 AB66 AC42                       AC54 AC74

Claims (2)

[Claims] 1. A focus lens group for focus adjustment,
Using a zoom lens group that is driven to change its position along the optical axis for zooming, and a signal obtained by the image pickup means when moved along the optical axis behind the zoom lens group. In an image pickup apparatus for forming an object image on the surface of an image pickup means by a zoom lens having a wobbling lens group for driving the focus lens group and performing focus adjustment, an electric drive means for electrically driving the wobbling lens. And an image pickup device having a manual drive means for manually driving the wobbling lens. 2. The image pickup apparatus according to claim 1, further comprising a switching unit capable of switching between the manual driving unit for the wobbling lens and the electric driving unit for the wobbling lens.