JPH06347682A - Mechanism for adjusting zoom lens device - Google Patents

Abstract

PURPOSE:To easily adjust the tracking of a lens by dividing a cam barrel into a barrel body on which a cam groove is formed and a cam shaft arranged in the barrel body and enabling the barrel body to move in a shaft direction with respect to the cam shaft. CONSTITUTION:The cam barrel is constituted of the barrel body 76 provided with the cam groove and the cam shaft 78 inserted into the barrel body 76. On one end of the shaft 78, three guide pieces 80 are formed at an interval of 120 deg.. The circumferential surfaces of the pieces 80 are brought into contact with the inside circumferential surface of the barrel body 76 and the aligning of the shaft 78 is executed. A spring hole 82 and a long hole 84 in a direction orthogonally crossing the shaft direction are formed on one guide piece 80. Besides, holes 86 and 88 are formed on the barrel body 76. By screwing a screw 90 in the hole 82 through the hole 86, the shaft 78 is fixed to the barrel body 76. Then, an eccentric pin 100 is inserted in the hole 84 through the hole 88. By loosening the screw 90 and turning the pin 100, the barrel body 76 is moved forward and backward and the tracking is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adjusting mechanism for a zoom lens device, and more particularly to an adjusting mechanism for 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 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. Optical axis 3
It moves back and forth with a certain relationship in the direction. This allows
Zooming is performed by the first lens group 4, the second lens group 5, and the third lens group 6.

Reference symbol I is a front lens, reference symbol J is an iris plate, and reference symbol K is an iris motor for driving the iris plate J.

[0005]

However, in the conventional zoom lens adjusting mechanism, since the front lens I is moved back and forth by the fine adjustment screw (not shown) during tracking adjustment, the lens frame that must be moved is It has the drawback of increasing. The present invention has been made in view of the above circumstances, and an object thereof is to provide an adjusting mechanism of a zoom lens device in which tracking adjustment of a lens is easy.

[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. The cam barrel is composed of a tubular body having the cam groove formed therein and a cam shaft provided in the tubular body and provided with a rotational force transmitting member, and finely moving the tubular body in a fine axial movement with respect to the cam shaft. It is characterized by having a mechanism.

[0007]

According to the present invention, the cam cylinder is divided into a cylinder body having a cam groove and a cam shaft having a power transmission member, and the cylinder body can be moved back and forth with respect to the cam shaft. Therefore, it is possible to perform the tracking adjustment by moving the cylinder during the tracking adjustment. As a result, since the front lens and the master lens can be fixed to each other, the structure is simplified, the number of parts is reduced, and the accuracy is easily obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The adjusting mechanism of the zoom lens device according to the present invention will be described in detail below with reference to the accompanying drawings. In FIG. 1, an inner focus type zoom lens device is shown, and four screws 1 are provided on a lens barrel body 10 and an upper surface 10A of the lens barrel body 10.
2, cover 12, which is fixed to the cover 16 via the positioning pins 14 and 14, is rotatably supported by the cover 16, and by mounting the cover 16 from above, the upper opening 10B of the lens barrel body 10 is provided. Cam cylinder 18 located at
It 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 535 and 35.
The front lens 20 and the master lens 34 in the lens barrel body 10
In the space portion 11 between the guide rods 22 and 2, which will be described later,
4, 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.

The lens frame 52 of the second moving lens group 30.
An iris unit 58 is integrally fixed to the. The iris unit 58 includes a diaphragm plate 60, an iris motor, a flexible printed board 62 and the like. 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 steady rest guide rod 26 is located in the recess 68 formed in the lower part of the lens frame 64. , Focus lens group 3
2 is guided by guide rods 24 and 26 and can be moved back and forth. In the lens frame 64 of the focus lens group 32,
The focus pieces 70 are connected, and the focus pieces 7
A screw nut 72 is formed at 0. This screw nut 7
A screw rod (not shown) of the focus motor 74 is fitted to the second lens 2, and the focus lens group 32 is moved back and forth by the rotation of the screw rod. That is, the focus motor 74 has the opening 10C formed on the side of the lens barrel body 10.
The screw rod of the focus motor 74 is fitted into the screw nut 72 of the focus lens group 32 by being inserted into the.

The cam barrel 18 is composed of 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. 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, 8 corresponding to the holes 82, 84 are formed in the cover 16.
7 are formed, and holes 86 and 88 corresponding to the holes 82 and 84 are also formed in the cylindrical body 76. Hole 8 as shown in FIG.
A screw 90 is screwed into the screw hole 82 through 5, 86 to fix the cam shaft 78 to the cylindrical body 76, and an eccentric pin is inserted into the long hole 84 through the holes 87 and 88 to loosen the screw 90. By rotating the eccentric pin, the cylinder 76 is moved back and forth to perform tracking adjustment. A gear 92 and a guide pin 94 are formed on the other end of the cam shaft 78.
Is fitted into the axial guide groove 96 of the cylindrical body 76, and
6 is guided in the axial direction.

A zoom motor 98 is attached to the end of the cover 16, and the zoom motor 98 is connected to a gear 92 via a gear transmission mechanism. When the zoom motor 98 is driven, the cam barrel 18 is rotated. The zoom lens device configured as described above is subjected to tracking adjustment as follows.

Tracking adjustment is made by focusing at infinity at the wide and tele ends. If adjustment is required, screw 9 as shown in Figure 2.
0 is loosened so that the barrel 76 of the cam barrel 18 can be moved with respect to the cam shaft 78 (that is, the lens barrel body 10). Next, the eccentric pin 100 is inserted into the long hole 84 through the hole 87 of the cover 16 and the hole 88 of the cylindrical body 76. In this state, the eccentric pin 100 is rotated clockwise or counterclockwise to move the cylindrical body 76 back and forth by a minute distance, and at the same time, the focus lens group 32 is moved to perform focusing. By repeating such an operation several times at the wide end and the tele end, the tracking adjustment is completed.

The fine adjustment mechanism is not limited to the eccentric pin and the elongated hole, and various types such as a combination of a biasing spring and a screw are applied.

[0015]

As described above, according to the adjusting mechanism of the zoom lens device of the present invention, the cam barrel is divided into the barrel body having the cam groove and the cam shaft disposed in the barrel body.
Since the cylindrical body is movable in the axial direction with respect to the cam shaft, the tracking adjustment of the lens can be easily performed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a zoom lens device to which an embodiment of an adjusting mechanism of a zoom lens device according to the present invention is applied.

FIG. 2 is a sectional view showing a main part of an adjusting mechanism of a zoom lens device according to the present invention.

FIG. 3 is a cross-sectional view showing an adjustment mechanism of 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 76 ... Cylindrical body 78 ... Cam barrel 84 ... Long hole 100 ... Eccentric pin

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. In the zoom lens device that rotates the cam barrel to move each movable lens group back and forth in the optical axis direction with a predetermined relationship, the cam barrel includes a tubular body in which the cam groove is formed, An adjusting mechanism for a zoom lens device, comprising: a cam shaft arranged inside a body and provided with a rotational force transmitting member; and a fine adjusting mechanism for finely moving a cylindrical body in the axial direction with respect to the cam shaft.