JP2000187146A - Lens drive mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a lens drive mechanism and to reduce the cost thereof. SOLUTION: This lens drive mechanism having a lens group 1 is equipped with a holding frame 2 including the lens group advancing/retreating in an optical axis direction, a guide member 3 guiding the holding frame so as to advance/retreat in the optical axis direction, a rotation checking member 4 checking the rotation of the holding frame in a direction orthogonal to an optical axis with the guide member as center, a driving device for driving and controlling the lens group in the optical axis direction, and the members 5 and 6 for transmitting driving force from the driving device to the holding frame holding the lens group, and advances/retreats the lens group 1 in the optical axis direction. The driving force transmitting member 6 is provided with elastic shapes 6b and 6c generating elastic force in two directions, that is, the optical axis direction and the direction orthogonal to the optical axis as an elastic member for removing backlash in a thrust direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving mechanism.

[0002]

2. Description of the Related Art As a conventional lens driving mechanism, one having a configuration shown in FIG. 3 is known. In the figure, 1 is a lens group, 2 is a lens frame, 3 is a guide bar, 4 is a U bar, 5
Is a stepping motor screw, 6 is a rack, 7
Denotes a rack spring, and 2d denotes a sleeve portion of the lens frame 2.
The lens driving mechanism shown in FIG. 3 includes a transmission member (a screw 5 and a rack 6) that transmits a force from an actuator to move the lens group 1 in the optical axis direction, and a transmission member and a lens group formed between the transmission member and the lens group. An elastic member (rack spring) 7 is provided to remove backlash in the thrust direction.

[0003]

However, in the above conventional example, since the elastic member for removing the play in the thrust direction is provided, the driving force transmitting member provided between the actuator and the lens group becomes large. This was an obstacle to downsizing the lens.

[0004] The present invention has been made in view of the problems in the above conventional example, and has as its object to reduce the size of a lens driving mechanism.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an elastic member provided on a driving force transmitting member for removing thrust play generated between the driving force transmitting member and a lens group. Are provided to replace the conventional driving force transmitting member and the elastic member, thereby realizing miniaturization.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows the configuration of a lens driving mechanism according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an objective lens group that advances and retreats in the optical axis direction, 2 denotes a lens frame including the lens group 1, 3 denotes a guide bar that guides the lens frame 2 in the optical axis direction, and 4 denotes a guide bar that guides the lens frame 2 in the optical axis direction. A U-bar 5 for preventing rotation in any direction in a plane orthogonal to the optical axis (hereinafter, referred to as an orthogonal direction to the optical axis) with respect to 3, and 5 for moving the lens frame 2 forward and backward in the optical axis direction. Screw of stepping motor to generate driving force, 6 is screw 5
Is a rack that converts a rotational force in a direction orthogonal to the optical axis of the optical axis into a force that advances and retreats in the optical axis direction.

[0007] Assembling is performed by attaching the mounting shaft 6d of the rack 6 to the sleeve 2d of the lens frame 2 in a state where the rack 6 is tilted 90 degrees to the right.
Is lowered to the position of the V-shaped portion 2a through a slit provided at the upper portion of the rack 6, and then rotated about 90 degrees to the left to engage the teeth of the screw 5 with the tooth-shaped portion 6a of the rack 6 from above.

In this lens drive mechanism, the tooth-shaped portion 6a of the rack 6 comes into contact with the screw 5, so that the elastic portion 6c of the rack 6
d, a rotational force in a direction perpendicular to the optical axis is generated, and the rotational force causes the mounting shaft 6d, which is the center of rotation of the rack 6, to be biased toward the V-shaped portion 2a of the lens frame 2, and the lens frame 2 The V-shaped sleeve hole 2b is
, And the U-groove 2 c is biased to the U-bar 4. Also, rattling in the optical axis direction generated at the contact portion between the screw 5 and the tooth-shaped portion 6a of the rack 6 due to the rotational force generated by the elastic portion 6c of the rack 6 is removed, and the U-shaped elastic portion of the rack 6 is removed. The play in the optical axis direction generated between the rack 6 and the lens frame 2 due to the force generated by the portion 6b can be removed.

As is apparent from a comparison between FIG. 1 and FIG.
Rack 6 which is a driving force transmitting member of the lens driving mechanism of FIG.
The occupied length A in the optical axis direction is 1/2 of that in FIG.
It is smaller.

(Second Embodiment) FIG. 2 shows the structure of a lens driving mechanism according to another embodiment of the present invention. The lens driving mechanism shown in the figure is different from that shown in FIG. 1 in that the position of the screw 5 and therefore the mounting direction of the rack 6 are changed, and the direction of the slit for passing the mounting shaft 6d of the rack 6 through the sleeve portion 2d is also changed. It is shifted 90 degrees to the right. Otherwise Figure 1
Are configured and act similarly.

[0011]

As described above, according to the present invention,
The extremely simplified lens barrel structure can reduce assembly costs, component costs, and accuracy control costs.Also, by eliminating thrust and radial play, image quality degradation and image shaking can be avoided, while miniaturizing the lens. Can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a lens driving mechanism according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a lens driving mechanism according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram of a lens driving mechanism according to a conventional example.

[Explanation of symbols]

1: lens group, 2: lens frame, 2a: V-shaped portion, 2
b: sleeve hole, 2c: V groove, 2d: sleeve
3: Guide bar, 4: U bar, 5: screw of stepping motor, 6: rack, 6a: tooth shape portion, 6
b, 6c: elastic part, 6d: mounting shaft, 7: rack spring.

Claims (2)

[Claims] 1. A holding frame including a lens group that moves in a direction of an optical axis in an optical system, a guide member that guides the holding frame to move in a direction of the optical axis, and an optical axis that moves the holding frame around the guide member. A rotation suppressing member for suppressing rotation in the orthogonal direction, a driving device for drivingly controlling the lens group in the optical axis direction, and a member for transmitting a driving force from the driving device to a holding frame holding the lens group. Wherein the driving force transmitting member has an elastic shape that generates elastic force in two directions, an optical axis direction and a direction orthogonal to the optical axis. 2. The elastic member according to claim 1, wherein the driving force transmitting member has an approximately U-shaped elastic shape portion that generates elastic force in two directions, an optical axis direction and a direction orthogonal to the optical axis. A lens driving mechanism.