JPH06347685A - Zoom lens device - Google Patents

Abstract

PURPOSE:To simplify structure and to reduce the number of parts by unidirectionally energizing a moving lens group by the elastic force of the flexible printed board or the lead wire of an iris unit. CONSTITUTION:The moving lens group 30 is guided by a guide pole 22 so that it can be moved forward and backward. When a cam barrel is rotated in a state where the cam pin 44 of the lens group 30 is inserted in the cam groove of the cam barrel, the lens group 30 is moved forward and backward in the relation of a prescribed zoom ratio decided by the cam groove. The iris unit 58 is integrally fixed to the lens frame of the lens group 30. Then, the flexible printed board 62 of the unit 58 is fixed to a lens barrel main body 10 with a screw 63 in a state where it is bent in an almost U-shaped. As the result, since the lens group 30 is always unidirectionally energized by the elastic force of the printed board 62, backlash between the pin 44 of the lens group 30 and the cam groove of the cam barrel can be eliminated.

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 an outer cam type zoom lens device in which a cam barrel is arranged laterally of a moving lens group.

[0002]

2. Description of the Related Art Conventionally, in this type of zoom lens, as shown in FIG. 3, a pair of guide rods 1 and 2 are arranged in parallel with an optical axis 3, and a moving lens is attached to the pair of guide rods 1 and 2. The first lens group 4, the second lens group 5, and the third lens group 6, which are the groups, are attached so as to be movable back and forth via lens frames 7, 8, and 9, respectively. Then, the cam cylinder A formed in a rod shape
Is arranged parallel to the optical axis 3 on the side of the lens frames 7, 8 and 9, and the cam pins 7A formed on the lens frames 7, 8 and 9 are
Cam grooves B, C, and D in which 8A and 9A are formed in the cam barrel A
Fit in.

A cam shaft E and a gear F are integrally formed at the end of the cam barrel A, and a zoom motor H is connected to the gear F via a gear mechanism G composed of a plurality of gears. . Therefore, when the cam barrel A is rotated by the rotational driving force from the zoom motor H, the first lens group 4, the second lens group 5 and the third lens group 6 are moved along the cam grooves B, C and D. It moves back and forth in a predetermined relationship in the optical axis 3 direction. Thereby, zooming by the first lens group 4, the second lens group 5, and the third lens group 6 is performed.

Reference numeral I is a front lens, reference numeral J is an iris plate fixed to the movable lens frame 8, and reference numeral K is an iris motor for driving the iris plate J.

[0005]

However, in the conventional zoom lens apparatus, a spring is provided for removing play between the cam groove C of the cam barrel A and the cam pin 8A of the moving lens group, and urged in one direction. However, the structure is complicated and the number of parts is increased. The present invention has been made in view of such circumstances, and an object thereof is to provide a zoom lens device having a simple structure.

[0006]

In order to achieve the above-mentioned object, the present invention arranges a cam barrel having a plurality of cam grooves on the side of a plurality of movable lens groups, and at the same time, each of the cam grooves. In the zoom lens device, each cam follower provided in each movable lens group is fitted, and each movable lens group is moved back and forth in the optical axis direction with a predetermined relationship by rotating the cam barrel. An iris unit is fixed to one of the moving lens groups, and the moving lens group to which the iris unit is fixed is biased in one direction by elastic force of a flexible printed board or lead wire of the iris unit. .

[0007]

According to the present invention, since the movable lens group is biased in one direction by the elastic force of the flexible printed board of the iris unit, the structure is simplified and the number of parts is reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A zoom lens device according to the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, an inner focus type zoom lens device is shown.
0, four screws 12, 1 on the upper surface 10A of the lens barrel body 10
The cover 16, which is fixed via 2, 12, 12 and the positioning pins 14 and 14, is rotatably supported by the cover 16 and is positioned in the upper opening 10B of the lens barrel body 10 by mounting the cover 16 from above. The cam barrel 18 is shown.

A front lens 20 is provided on the front of the lens barrel body 10.
The master lens 34 is fixed to the rear part of the lens barrel body 10 via the rear frame 36. Rear frame 36 is screw 3
It is screwed to the lens barrel body 10 by 5, 35 and 35. In the space 11 between the front lens 20 and the master lens 34 in the lens barrel body 10, a guide rod 22, which will be described later,
24, 26, first moving lens group (variator lens) 2
8, second moving lens group (compensator lens) 30,
A focus lens group 32 is arranged, the space 11 in the lens barrel body 10 communicates with the upper opening 10B, and space is formed in the cam grooves 38, 40 of the cam barrel 18 located in the upper opening 10B as described later. The driven pin 42 of the first moving lens group 28 located in the portion 11 and the driven pin 44 of the second moving lens group 30 are fitted into each other, and the rotation of the cam barrel 18 causes the first and second moving lens groups 28 and 30 to move back and forth. Move. That is, the guide rod 24 is inserted into the guide hole 48 formed in the upper portion of the lens frame 46 of the first moving lens group 28, and the lens frame 4 is inserted.
A steadying guide rod 26 is located in a recess 50 formed in the lower portion of 6, and the first moving lens group 28 is a guide rod 24,
It is guided by 26 and can move back and forth. Similarly, the guide rod 22 is inserted into the guide hole 54 formed in the upper portion of the lens frame 52 of the second moving lens group 30, and the steady rest guide is provided in the recess 56 formed in the lower portion of the lens frame 52. The rod 26 is located, and the second movable lens group 30 is guided by the guide rods 22 and 26 so that it can move back and forth. Therefore, when the cam barrel 18 rotates with the cam pins 42 and 44 of the first and second moving lens groups 28 and 30 fitted in the cam grooves 38 and 40 of the cam barrel 18, the first and second moving lens groups 28 and The reference numeral 30 moves back and forth in a relationship of a predetermined zoom ratio determined by the cam grooves 38 and 40.

An iris unit 58 is integrally fixed to the lens frame 52 of the second moving lens group 30.
The iris unit 58 is composed of an iris plate 60, a flexible printed board 62, and the like. The flexible printed board 62 of the iris unit 58 has screws 63, 63 in a state of being bent into a substantially U shape as shown in FIG.
It is fixed to the lens barrel body 10 by. As a result, the second movable lens group 30 is biased leftward in FIG.

The guide rod 24 is inserted into the guide hole 66 formed in the upper part of the lens frame 64 of the focus lens group 32, and the concave portion 6 formed in the lower part of the lens frame 64.
A steadying guide rod 26 is located at 8, and the focus lens group 32 is guided by the guide rods 24 and 26 to be movable back and forth. Lens frame 6 of focus lens group 32
The focus piece 70 is connected to the focus piece 4, and a screw nut 72 is formed on the focus piece 70. The screw nut 72 is fitted with a screw rod (not shown) of the focus motor 74, and the focus lens group 32 is moved back and forth by the rotation of the screw rod. That is, the focus motor 74 is inserted into the opening 10C formed on the lateral side of the lens barrel body 10 so that the focus motor 7 is
4 is a screw nut 72 of the focus lens group 32.
Mate with.

The cam barrel 18 comprises a barrel 76 having cam grooves 38 and 40, and a cam shaft 78 inserted into the barrel 76. Guide pieces 80, 80, 80 are formed at 120 ° intervals at one end of the cam shaft 78.
When the cam shaft 78 is inserted into the cylindrical body 76, the peripheral surfaces of 0 and 80 come into contact with the inner peripheral surface of the cylindrical body 76 to center the cam shaft 78. Therefore, at least three guide pieces 80, 80, 80 are required. A screw hole 82 and a long hole 84 in a direction orthogonal to the axial direction are formed in one guide piece 80 of the cam shaft 78, while holes 85 and 87 corresponding to the holes 82 and 84 are formed in the cover 16. The cylindrical body 76 is also formed with holes 86 and 88 corresponding to the holes 82 and 84. A screw 90 is screwed into the screw hole 82 through the holes 85 and 86 to allow the cam shaft 7 to move.
8 is fixed to the cylindrical body 76, and the long hole 8 is formed through the holes 87 and 88.
An eccentric pin is inserted in 4 and the eccentric pin is rotated to move the cylinder 76 back and forth to perform tracking adjustment. A gear 92 and a guide pin 94 are formed at the other end of the cam shaft 78, and the guide pin 94 is fitted into an axial guide groove 96 of the tubular body 76 to guide the tubular body 76 in the axial direction and the tubular body 76. And rotate together.

A zoom motor 98 is attached to an end portion of the cover 16, the zoom motor 98 is connected to a gear 92 via a gear transmission mechanism, and when the zoom motor 98 is driven, the cam barrel 18 is rotated. According to the zoom lens device configured as described above, the second movable lens group 30 is always urged in one direction by the elastic force of the flexible printed board 62 of the iris unit 58. The play between the cam pin 44 and the cam groove 40 of the cam barrel 18 can be removed.

In the above embodiment, the flexible printed board 6 is used.
Although the elastic force of 2 was used, it is not limited to this,
You can also use a lead wire that has a restoring force.

[0015]

As described above, according to the zoom lens device of the present invention, the flexible printed board or the lead wire of the iris unit fixed to the moving lens group in order to urge the moving lens group in one direction. Since the elastic force is used, the structure is simplified and the number of parts is reduced.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a main part of a zoom lens device according to the present invention.

FIG. 3 is a cross-sectional view showing a conventional zoom lens device.

[Explanation of symbols]

 10 ... Lens barrel 18 ... Cam barrel 28 ... First moving lens group 30 ... Second moving lens group 32 ... Focus lens group 38, 40 ... Cam groove 58 ... Iris unit 62 ... Flexible printed board 76 ... Cylindrical body 78 ... Cam axis

Claims (1)

[Claims] 1. A cam barrel in which a plurality of cam grooves are formed is arranged laterally of a plurality of moving lens groups, and each cam follower provided in each moving lens group is fitted into each of the cam grooves. Then, in a zoom lens device for rotating each of the movable lens groups back and forth in the optical axis direction by rotating the cam barrel, an iris unit is fixed to one of the movable lens groups, and the iris unit is A zoom lens device characterized in that the fixed moving lens group is biased in one direction by the elastic force of a flexible printed board or a lead wire of the iris unit.