JP2003202489A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust the relative position of a hard printed board and a brush, as for a lens barrel wherein a prescribed electric signal is generated by making a code pattern formed on the hard printed board and the brush rub each other. <P>SOLUTION: As for the lens barrel provided with the hard printed board on which electric parts are loaded and an electric circuit and the code pattern are formed, and the brush which is attached to a rotating member rotating around an optical axis and which comes in slide contact with the code pattern, the hard printed board is formed so that the brush attaching position of the rotating member may be exposed. <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 optical device having a printed circuit board, and more particularly to a lens mirror mountable on a single-lens reflex camera or the like having an encoding pattern such as zoom on an electric component mounting board fixed inside. It is about the cylinder.

[0002]

2. Description of the Related Art In recent years, in interchangeable lens systems for single-lens reflex cameras, autofocusing has progressed, and devices having a lens driving motor and a control electric circuit inside a lens barrel have become common.

It is well known that a flexible printed circuit board provided with an encode pattern and an encode brush are provided in the lens barrel in order to detect changes in the lens position due to focusing or zooming.

A configuration as shown in FIG. 3 is known as an example using the configuration disclosed in Japanese Patent Publication No. 07-027097. FIG. 3 is a zoom lens having a four-group configuration, 1 is a mount having a claw portion 1a for connecting to the camera body,
Reference numeral 2 denotes a fixed cylinder connected to the mount 1 and having a guide groove (not shown) parallel to the optical axis.

A zoom operation ring 3 is rotatably supported on the fixed barrel 2, and has a cam groove (not shown) and a cam follower 3a on the inner circumference. A female helicoid ring 4 has a convex cam 4a that engages with the cam follower 3a, a convex portion (not shown) that engages with a guide groove (not shown) of the fixed barrel 2, and a helicoid 4b on the inner periphery. It is provided.

Reference numeral 5 is a first lens holding frame for holding the first lens unit L1, and a helicoid 5a screwed with the helicoid 4c is provided on the outer circumference. A second lens holding frame 6 holds the second lens group L2, and is fixed to the tip of a fourth lens holding frame 7 holding the fourth lens group L4.

A cam groove (not shown) is provided on the inner circumference of the fourth lens holding frame 7, and a guide groove (not shown) of the fixed barrel 2 and a cam groove (not shown) of the zoom operation ring 3 are provided on the outer circumference. (Shown)
A roller 7b that engages with is provided.

Reference numeral 8 is a third lens holding frame for holding the third lens unit L3, and is provided with a roller 8a for engaging with a cam groove (not shown) of the fourth lens holding frame 7. Reference numeral 9 denotes a third lens holding frame key, which is fixed to the inner circumference of the zoom operation ring 3.
The tip extending in the optical axis direction engages with the third lens holding frame 3 to rotate the third lens holding frame 3.

The encode brush 10 is connected to the rear end with screws or the like. Reference numeral 11 denotes a contact member that is attached to the mount 1 and serves as an electrical contact with the camera body, and is connected by a flexible printed board 13 and an annular disk-shaped hard printed board 12 on which electrical parts are mounted and which forms an electric circuit. Has been done.

The hard printed circuit board 12 is fixed to the fixed cylinder 2 with screws or the like (not shown), and is provided with an encode pattern 12a for detecting the rotation angle of the zoom operation ring 3 by sliding contact with the encode brush 10.

In the above-mentioned conventional example, the third lens holding frame key 9 attached to the zoom operation ring 3 is rotated by the zoom.
A hard printed circuit board 12 on which an encode brush 10 is attached and an encode pattern 12a is mounted on an electric component
By providing it on the top, the overall length of the lens barrel is shortened, the diameter of the lens barrel is suppressed from increasing, and the flexible printed circuit board is not used, so that the cost is also reduced.

[0012]

However, in the above-mentioned conventional example, it is necessary to attach the hard printed circuit board 12 having the encode pattern 12a after attaching the encode brush 10 to the third lens holding frame key 9, so that the encode brush is required. 10 and rigid printed circuit board 12
Due to errors such as the above, there were cases where encoding could not be performed accurately.

In such a case, the position of the hard printed circuit board 12 was conventionally adjusted, but if the amount of adjustment is exceeded, the hard printed circuit board 12 is once removed and the position of the encode brush 10 is adjusted. It had to be adjusted, which was very time-consuming.

[0014]

In order to achieve the above-mentioned object, in the present invention, electric parts are mounted, and an electric circuit and a code pattern are formed in a plane perpendicular to the optical axis. A rigid printed circuit board, a movable member rotatable about an optical axis, and a brush attached to the movable member and in contact with the code pattern, wherein the code pattern is in sliding contact with the brush,
In the lens barrel that generates a signal according to the code pattern, the rigid printed circuit board is formed such that a mounting portion of the brush of the movable member is exposed, whereby the rigid printed circuit board 12 is provided. The position of the encode brush 10 can be adjusted without removing the lens barrel, and a lens barrel having good workability can be provided.

The area of the rigid printed board 12 is characterized in that the shape of the rigid printed board formed so that the attachment portion of the brush of the movable member is exposed is a hole shape. Therefore, it is possible to provide the lens barrel in which the position of the encode brush 10 can be adjusted without lowering the design freedom of the electric circuit.

Further, since the hole shape is a through hole that electrically connects both surfaces of the rigid printed circuit board, unnecessary through holes can be reduced and the position of the encode brush 10 can be adjusted. It becomes possible to provide a possible lens barrel.

[0017]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a lens barrel showing an embodiment of the present invention. FIG. 2 is a view as seen from the direction of arrow A in FIG. 1 with the mount 1 removed.

FIG. 1 shows a zoom lens having a four-group structure, 1 being a mount having a claw portion 1a for connecting to a camera body,
A fixed cylinder 2 is connected to the mount 1 with screws or the like (not shown), and has a plurality of guide grooves (not shown) parallel to the optical axis.

A zoom operation ring 3 is rotatably supported on the fixed barrel 2, and has a cam groove (not shown) and a cam follower 3a on the inner circumference. A female helicoid ring 4 has a convex cam 4a that engages with the cam follower 3a and a convex portion (not shown) that engages with a guide groove (not shown) provided on the fixed barrel 2 on the outer periphery. A helicoid 4b is provided.

Reference numeral 5 is a first lens holding frame for holding the first lens unit L1, and a helicoid 5a screwed with the helicoid 4b is provided on the outer circumference. A second lens holding frame 6 holds the second lens group L2, and is fixed to the tip of the fourth lens holding frame 7 holding the fourth lens group L4 by adhesion or the like.

A cam groove (not shown) is provided on the inner circumference of the fourth lens holding frame 7, and a guide groove (not shown) of the fixed barrel 2 and a cam groove (not shown) of the zoom operation ring 3 are provided on the outer circumference. (Shown)
A roller 7b that engages with is provided.

Reference numeral 8 is a third lens holding frame for holding the third lens unit L3, and is provided with a roller 8a for engaging with a cam groove (not shown) of the fourth lens holding frame 7. Reference numeral 9 denotes a third lens holding frame key, which is fixed to the inner circumference of the zoom operation ring 3.
The tip extending in the optical axis direction engages with the third lens holding frame 3 to rotate the third lens holding frame. Also, at the rear end,
The encode brush 10 made of metal is connected by screws or the like.

Reference numeral 11 denotes a contact member which is attached to the mount 1 and serves as an electrical contact with the camera body. The rigid printed circuit board 12 and the flexible printed circuit board are annular disk-shaped and have electric parts mounted thereon to form an electric circuit. It is connected by 13.

The hard printed circuit board 12 is fixed to the fixed cylinder 2 with screws or the like (not shown), and is provided with an encode pattern 12a for detecting the rotation angle of the zoom operation ring 3 by slidingly contacting the encode brush 10.

The hard printed circuit board 12 is provided with holes 12b and 12c at a position where the encode brush 10 attached to the third lens holding frame key 9 is opposed so that a part of the encode brush 10 is exposed. .

In the above structure, when the zoom operation ring 3 is rotated to perform a zoom operation, a predetermined electric signal is generated due to conduction / non-conduction between the encode pattern 12a provided on the hard printed board 12 and the encode brush 10. Then, the rotation angle of the zoom operation ring, that is, the position of each lens group can be detected.

In order to perform accurate detection, it is necessary to adjust the relative positions of the hard printed board 12 and the encode brush 10 during assembly. First, the zoom operation ring 3 is rotated so that the sliding contact portion of the encode brush 10 is on the side of the encode pattern 12a where the check pattern is provided.

Normally, the zoom operation ring 3 is fixed so as not to rotate unintentionally during the adjustment in the tele or wide state. In such a state, first, the position of the hard printed board 12 is moved and adjusted while confirming the electrical continuity of the encode pattern 12a.

However, after this adjustment, the rigid printed circuit board 12 is
It is conceivable that the hard printed circuit board 12 may move due to friction with the screws when the screws are fixed to the fixed barrel 2. In addition, there may be a case where adjustment is impossible within the adjustment range of the rigid printed circuit board 12.

In such a case, the rigid printed board 1
After fixing 2, insert a tool having a clip-like end from the hole 12c, hold the encode brush 10, and then insert a tool such as a screwdriver from the hole 12b.
The position of the encode brush 10 can be adjusted by loosening the screw fixing the encode brush 10 to the third lens holding frame key 9.

After the adjustment, when tightening the screw fixing the encode brush 10 to the third lens holding frame key 9, if the encode brush 10 is held by a tool inserted through the hole 12c, friction with the screw will occur. Thus, the encoding brush 10 can be fixed without moving.

If the hole 12b is formed as a through hole that electrically connects the surfaces of the hard printed board 12 to each other,
Since the inner periphery of the hole 12b is plated, the risk of dust and the like due to unintentional sliding on the hard printed circuit board 12 during driver insertion and rotation is reduced, and the number of through holes can be reduced.

[0033]

As described above, according to the present invention, a hard printed board on which electric components are mounted and electric circuits and code patterns are formed in a plane perpendicular to the optical axis, A movable member rotatable about an optical axis and a brush attached to the movable member and in contact with the code pattern are provided, and a signal corresponding to the code pattern is generated by the brush slidingly contacting the code pattern. In the lens barrel that generates, the rigid printed circuit board is formed so that the mounting portion of the brush of the movable member is exposed, and thus the position of the brush can be adjusted without removing the rigid printed circuit board. It is possible to provide a lens barrel that can be adjusted and has good workability.

Further, the shape of the rigid printed circuit board formed so that the mounting portion of the brush of the movable member is exposed is a hole shape, so that the area of the rigid printed circuit board is reduced. It is possible to provide a lens barrel in which the position of the brush can be adjusted without sacrificing the degree of freedom in designing the electric circuit while ensuring the maximum.

Further, since the hole shape is a through hole that electrically connects both surfaces of the rigid printed circuit board, unnecessary through holes can be reduced and the position of the brush can be adjusted. It is possible to provide a lens barrel.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lens barrel that is an embodiment of the present invention.

FIG. 2 is a view on arrow A shown in FIG. 1, which is an embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional lens barrel.

[Explanation of symbols]

1 mount 2 fixed cylinder 3 Zoom operation ring 4 Female helicoid ring 5 First lens holding frame 6 Second lens holding frame 7 Fourth lens holding frame 8 Third lens holding frame 9 Third lens holding frame key 10 Encoding brush 11 Contact member 12 Rigid printed circuit board 13 Flexible printed circuit board

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Suzuki             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H044 AJ04 DE06 EC07

Claims (3)

[Claims] 1. A hard printed board on which electric parts are mounted and an electric circuit and a code pattern are formed in a plane perpendicular to the optical axis, and a movable member rotatable about the optical axis. A brush that is attached to the movable member and is in contact with the code pattern, and the brush is in sliding contact with the code pattern,
In the lens barrel that generates a signal according to the code pattern, the rigid printed circuit board is formed so that a mounting portion of the brush of the movable member is exposed. 2. The lens mirror according to claim 1, wherein a shape of the rigid printed circuit board that is formed so that the attachment portion of the brush of the movable member is exposed is a hole shape. Cylinder. 3. The lens barrel according to claim 2, wherein the hole shape is a through hole that electrically connects both surfaces of the rigid printed circuit board.