JPH07104165A - Zoom lens device - Google Patents

Abstract

PURPOSE:To enable backfocusing from the front side of a zoom lens device and also to suppress the deviation of focus on an object image when a case expands and contracts due to temperature change. CONSTITUTION:Backfocusing is executed by rotating an adjusting screw 90 from the front side of the zoom lens device and moving a mobile lens group in a photographic optical axis direction. Also, the trailing end part of a shaft 62 is made to abut on the trailing end of the case by a pressing force of a leaf spring 82, then, the mobile lens group is positioned by regarding the trailing end of the case as a reference through a side cam cylinder 32. Thus, the positional deviation of the mobile lens group with reference to the focal surface of the trailing end of the case can be suppressed even when the case expands and contracts due to the temperature change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens device, and more particularly to a compact camera or a simplified camera-integrated VT.
The present invention relates to a zoom lens device applied to R.

[0002]

2. Description of the Related Art Conventionally, this type of zoom lens device has
There is an outer cam type in which a cam barrel (hereinafter, referred to as a "side cam barrel") is arranged beside a plurality of moving lens groups housed in a case. Such a zoom lens device is
A follower provided on the lens frame of the moving lens group is fitted into a plurality of cam grooves formed in the side cam barrel, and the side cam barrel is rotated to cause each moving lens group to have a predetermined relationship in the optical axis direction. And is moved back and forth to form a subject image on the focal plane located at the rear end of the case.

The front end of the side cam barrel is pivotally supported in a front through hole formed in the case, and the rear end of the side cam barrel is biased forward in the rear through hole formed in the case. It is pivotally supported via a spring. Further, a screw member is provided in the front through hole from the front side of the case, and by screwing this screw member into contact with the front end of the side cam cylinder, the side cam cylinder is finely adjusted against the biasing force of the spring. Moving. by this,
Move the lens frame back and forth to adjust the back focus.

[0004]

However, in the conventional zoom lens apparatus, since the front end of the side cam barrel is in contact with the case by the urging force of the spring, the case expands and contracts due to temperature change, and the case There is a drawback in that the position of the side cam barrel with respect to the rear end is displaced in the optical axis direction, and the positional relationship of each moving lens group with respect to the focal plane is destroyed, resulting in defocusing.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a zoom lens device which is not out of focus even if the case expands or contracts due to a change in temperature.

[0006]

In order to achieve the above-mentioned object, the present invention arranges a cam barrel having a plurality of cam grooves formed beside a plurality of movable lens groups housed in a case. At the same time, a follower provided on the lens frame of each moving lens group is fitted in each cam groove, and each moving lens group is moved back and forth in the optical axis direction with a predetermined relationship by rotating the cam barrel. In a zoom lens device for zooming, the cam barrel is coaxially housed to movably support the cam barrel in the optical axis direction, and a front end portion and a rear end portion of the zoom lens device pivot to the case. A shaft supported so that it can be rotated from the front side of the case by connecting the cam cylinder and the shaft to a biasing means that biases the shaft rearward to bring the rear end of the shaft into contact with the case. Adjustment to move the cam barrel in the optical axis direction with respect to the axis. A screw member, and the adjustment screw member is rotated to move each of the movable lens groups in the optical axis direction through the cam barrel so that the focal point of the movable lens group is the focal point of the rear end portion of the case. It is characterized by matching the surface.

[0007]

According to the present invention, the cam barrel is movably supported in the optical axis direction by the shaft coaxially housed in the cam barrel, and the front end portion and the rear end portion of the shaft are rotatable with respect to the case. To support. The urging means urges the shaft rearward so that the rear end of the shaft contacts the rear end of the case. The adjustment screw member connects the cam barrel and the shaft so that the cam barrel moves in the optical axis direction with respect to the shaft when the adjustment screw member is rotated, and the adjustment screw member is rotatably arranged from the front side of the case. I set it up. Therefore, since the rear end of the shaft is in contact with the rear end of the case by the urging force of the urging means, the movable lens group is positioned via the cam barrel with the rear end of the case as a reference. Further, the adjustment screw member is rotated from the front of the zoom lens device to move the movable lens group in the optical axis direction via the cam barrel to perform back focus adjustment.

[0008]

The preferred embodiments of the zoom lens device according to the present invention will be described in detail below with reference to the accompanying drawings. 1 is a perspective view of a zoom lens device according to the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a sectional view taken along line 3-3 of FIG. The zoom lens device 10 includes a case 12, and a first moving frame 24, a second moving frame 28, and a side cam barrel 32 are included in the case 12.
Is stored. The first moving frame 24 is arranged at the front end portion of the zoom lens device 10, and the second moving frame 28 is arranged behind the first moving frame 24. The side cam barrel 32 is provided on the right side of the first moving frame 24 and the second moving frame 28.
Are arranged.

The first moving frame 24 has a first photographing lens group 44.
Is attached to the second moving frame 28, and the second taking lens group 54 is attached to the second moving frame 28. First taking lens group 4
4 and the optical axis of the second taking lens group 54 are the taking optical axis 3
It is arranged coaxially with No. 4. First moving frame 24 and second
The moving frame 28 is attached to the case 12 via a guide rod (not shown).
It is movably supported in the direction of the photographing optical axis 34 (that is, the front-back direction of the zoom lens device 10).

A CCD unit 30 is mounted behind the first moving frame 24 and the second moving frame 28. The side cam barrel 32 disposed on the right side of the first moving frame 24 and the second moving frame 28 is disposed parallel to the photographing optical axis 34, and a shaft 62 described later is fitted in the side cam barrel 32. There is. A gear 64 is integrally formed with the shaft 62, and the gear 64 is meshed with a gear 68 of a motor 66.

Further, cam grooves 70 and 72 are formed on the outer peripheral surface of the side cam barrel 32, and driven pins (not shown) of the first moving frame 24 are respectively formed in the cam grooves 70 and 72.
The driven pin 74 of the second moving frame 24 is movably fitted therein. Therefore, the driving force from the motor 66 is applied to the gear 6
When transmitted via 8 and 64, the side cam barrel 32 rotates. In this case, the first moving frame 24 and the second moving frame 28 are
It moves back and forth along the cams 70 and 72 in a direction toward each other (tele side direction) and a direction away from each other (wide side direction) on the photographing optical axis 34. As a result, the photographing magnification of the subject image changes.

Further, a plate 80 is formed at the front end of the side cam barrel 32, and an opening hole 80A is formed in the plate 80 coaxially with the side cam barrel 32.
The front end portion 62A of the shaft 62 described above is fitted into the opening hole 80A. A front end pin 62B is coaxially formed at the front end of the front end portion 62A, and the front end pin 62B is fixed to the fixed frame 22.
Is fitted into the opening hole 22A. The tip pin 62B slightly protrudes from the fixed frame 22, and the tip pin 6 protruding
2B is in contact with the leaf spring 82. The leaf spring 82 is fixed to the fixed frame 22 via a screw 84. The tip pin 62B is biased rearward by the leaf spring 82.

A rear end pin 62C is provided at the rear end of the shaft 62.
Are formed coaxially, and the rear end pin 62C is fixed frame 2
It is fitted in the second concave portion 22B. The recess 22B is a CCD
It is formed at the rear end of the fixed frame 22 near the focal plane of the unit 30. The tip pin 62B of the shaft 62 is attached to the leaf spring 8
Since it is pressed by 2, the rear end pin 62C of the shaft 62 contacts the bottom of the recess 22B. As a result, the shaft 62 is positioned with reference to the bottom of the recess 22B. Also, axis 6
2 rotates about the axis, but in the front-back direction (arrow A-
Movement in the B direction) is restricted.

A flange 62D is formed at the rear end of the shaft 62, and the rear end of the side cam barrel 32 is slidably supported by the flange 62D. An elongated hole 32A is formed at the rear end of the side cam barrel 32 so as to extend in the axial direction. A screw 86 is fitted in the long hole 32A, and the screw 86 is screwed to the flange 62D. As a result, the side cam barrel 32 moves in the front-rear direction (direction of arrow AB) independently of the shaft 62, and the side cam barrel 32 also moves.
Rotates integrally with the shaft 62 about the axis.

A stopper 88 is formed at the front end of the shaft 62, and an adjusting screw 90 is screwed to the stopper 88. The adjusting screw 90 is the opening hole 80B of the plate 80.
It is rotatably supported by. Further, a compression spring 92 is arranged between the stopper 88 and the plate 80,
The compression spring 92 is connected to the side cam barrel 32 via the plate 80.
Is urged in the forward direction (direction of arrow A). Therefore, the plate 80 of the side cam barrel 32 is brought into contact with the head of the adjusting screw 90. Further, by biasing the side cam barrel 32 in the forward direction (direction of arrow A) with the compression spring 92, the adjustment screw 9
The looseness between 0 and the stopper 88 is removed.

Further, an adjusting opening hole 22C is formed in front of the adjusting screw 90 of the fixed frame 22.
The adjusting screw 90 can be rotated from the front via 2C. When the adjusting screw 90 is rotated clockwise, the side cam barrel 32 moves in the direction of arrow B against the urging force of the compression spring 92, and when the adjusting screw 90 is rotated counterclockwise, the side cam barrel 32 moves. The compression spring 92 moves in the arrow A direction in which the biasing force acts.

In this case, as described above, the side cam barrel 3
2 to the first moving frame 2 via the cam groove 70 and the cam groove 72.
4. Since the second moving frame 28 is connected, when the side cam barrel 32 moves in the front-back direction, the first moving frame 24 and the second moving frame
The moving frame 28 and the side cam barrel 32 move back and forth along the photographing optical axis 34. Therefore, by rotating the adjusting screw 90 clockwise or counterclockwise, the first,
The back focus of the second lens group 44, 54 is adjusted, and the focus of the first and second lens group 44, 54 is set to the image sensor 3.
Aligned to the 0 focal plane.

Since the shaft 62 is positioned by the urging force of the leaf spring 82 with reference to the bottom of the recess 22B, the first and second lens groups 44, 54 are positioned with reference to the bottom of the recess 22B. It Therefore, the first and second lens groups 4
4, 54 are positioned with reference to the vicinity of the focal plane of the image sensor 30 as a reference. 1 and 2, 96 is a finder, and the finder 96 includes a finder eyepiece 98, an eyepiece 100, a first prism 102, and a second prism 1.
04 (see FIG. 1) and the opening 106. The finder 90 displays the subject light incident on the opening 106 as the first light.
The subject light guided to the second prism 104 via the prism 102, and the subject light guided to the second prism 104 forms a subject image on the finder eyepiece 98 via the eyepiece lens 100.

Next, the operation of the zoom lens device configured as described above will be described. First, a driver is inserted into the adjustment screw 90 from the front of the zoom lens device 10 through the opening 22C, and the driver is operated to rotate the adjustment screw 90 in the clockwise direction and the counterclockwise direction. Adjustment screw 9
When 0 rotates in the clockwise direction and the counterclockwise direction, the side cam barrel 32 moves in the front-rear direction (arrow AB direction), and the first moving frame 24 and the second moving frame 28 together with the side cam barrel 32. It moves in the direction of arrow AB along the photographing optical axis 34. In this case, the driver is operated so that the focal points of the first and second lens groups 44 and 54 are aligned with the focal plane of the image sensor 30, and the adjusting screw 90 is rotated clockwise and counterclockwise. Then, when the focal points of the first and second lens groups 44 and 54 are aligned with the focal plane of the image sensor 30, the adjusting screw 9
0 rotation is stopped and the side cam barrel 3 is screwed with a screw (not shown).
2 and the shaft 62 are fixed. This completes the back focus adjustment.

In this case, since the shaft 62 is positioned with reference to the bottom of the recess 22B, the first and second lens groups 44 and 54 are positioned with reference to the bottom of the recess 22B via the side cam barrel 32. It's Therefore, even if the case expands or contracts due to a change in temperature, it is possible to suppress the positional deviation of the first and second lens groups 44 and 54 with respect to the focal plane of the image sensor 30. In this way, the positional relationship between the first and second lens groups 44 and 54 with respect to the focal plane of the image sensor 30 can be maintained in a state in which the back focus is adjusted, so that the subject image is not out of focus.

Further, since the adjusting screw 90 can be operated by the driver from the front of the zoom lens device 10, the viewfinder 90 is attached to the zoom lens device 10,
Even if the rear of the zoom lens device 10 is covered with the finder 90, the back focus can be adjusted.

[0022]

As described above, according to the zoom lens device of the present invention, since the rear end of the shaft is in contact with the rear end of the case by the urging force of the urging means, the movable lens group is It is positioned with the rear end of the case as a reference via the cam barrel. Therefore, even if the case expands or contracts due to a change in temperature, it is possible to suppress the positional deviation of the moving lens group with respect to the focal plane at the rear end of the case. In this way, when the case expands or contracts due to a change in temperature, the positional relationship of the moving lens group with respect to the focal plane can be maintained in a state in which the back focus is adjusted, so that the subject image is not out of focus.

Further, the back focus is adjusted by rotating the adjusting screw member from the front of the zoom lens device and moving the movable lens group in the optical axis direction through the cam barrel, so that the viewfinder is attached to the zoom lens device. Installed,
Even if the rear of the zoom lens device is covered with the viewfinder, the back focus can be adjusted.

[Brief description of drawings]

FIG. 1 is a perspective view of a zoom lens device according to the present invention.

2 is a sectional view taken along line 2-2 of FIG.

3 is a sectional view taken along line 3-3 of FIG.

[Explanation of symbols]

 10 ... Zoom lens device 12 ... Case 24, 28 ... Lens frame 32 ... Side cam barrel (cam barrel) 34 ... Shooting optical axis (optical axis) 44, 54 ... Lens group (moving lens group) 62 ... Axis 70, 72 ... Cam Groove 74 ... Follower 82 ... Leaf spring (biasing means) 90 ... Adjusting screw (adjusting screw member) 92 ... Compression spring (elastic member)

Claims (2)

[Claims] 1. A cam barrel having a plurality of cam grooves is arranged beside a plurality of moving lens groups housed in a case, and each cam groove is provided on a lens frame of each moving lens group. In the zoom lens device for zooming by fitting the follower and rotating the cam barrel, the moving lens groups are moved back and forth in the optical axis direction in a predetermined relationship. A shaft that is housed coaxially, supports the cam barrel so as to be movable in the optical axis direction, and has a front end portion and a rear end portion that are rotatably supported by the case, and biases the shaft rearward. Urging means for contacting the rear end of the shaft with the case, the cam barrel and the shaft are coupled, and the cam barrel is rotated from the front side of the case to move the cam barrel in the optical axis direction with respect to the shaft. An adjusting screw member that moves, and A zoom lens device, wherein each of the movable lens groups is moved in the optical axis direction via a cam barrel so that the focal point of the movable lens group is aligned with the focal plane of the rear end portion of the case. 2. The zoom according to claim 1, further comprising an elastic member which is arranged between the cam barrel and the shaft and biases the cam barrel in one of the optical axis directions. Lens device.