JPH06201980A - Lens driving device - Google Patents

Abstract

PURPOSE:To provide a compact lens driving device and to apply it to various camera units by disposing an actuator for a variable power optical system between a diaphragm and an image pickup surface being a CCD and disposing an actuator for focusing between a forefront lens and the diaphragm. CONSTITUTION:A stepping motor 9 for driving a variable power lens is fixed to a diaphragm unit 18, and a screw bar 9a being the output shaft of the motor 9 is meshed with the screw part 7a of a rack 7 without backlash. A stepping motor 15 for driving a focusing lens is fixed to the unit 18. Furthermore, the unit 18 for adjusting light quantity, which is integrally fixed to a lens barrel 1, has a driving part 19, and the driving part 19 actuates a diaphragm blade 20, so that the light quantity projected to the CCD 21 is adjusted. Namely, the actuator for the variable power optical system (stepping motor) 9 is disposed between the diaphragm and the image pickup surface, and the actuator for focusing (stepping motor) 15 is disposed between the forefront lens and the diaphragm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving device for an image pickup light amount system, such as a still camera and a camera.

[0002]

2. Description of the Related Art A conventional video lens unit equipped with a lens driving device of this type includes a lens barrel unit for holding an optical system, an actuator for driving a lens and an interlocking mechanism, a diaphragm for adjusting the amount of light, and a diaphragm driving mechanism for moving. It is composed of a sensor mechanism for detecting the position of the lens, an electrical mounting portion for making an electrical connection, and the like. In the configuration layout, the actuator and the interlocking mechanism are attached to the outside of the lens barrel unit holding the optical system.

[0003]

However, in the above-mentioned conventional example, since the actuator for driving the lens and the interlocking mechanism are arranged outside the lens barrel unit, the overall shape of the lens unit becomes large.

On the other hand, in recent years, rear focus zooming has been attempted in order to reduce the size of the lens unit, but the actuator and the interlocking mechanism that largely extend outside the lens barrel unit have the shape of the photographing device. Since the layout needs to be done together, it is difficult to obtain the optimum layout of the lens unit, and the lens unit of the image pickup apparatus is made large due to the layout limitation of the lens unit. Further, since the layout of the lens unit is suitable for each photographing device unit, there is a problem that the lens unit has no generality and it is difficult to divert it to another photographing device.

An object of the present invention is to obtain a lens driving device which solves the above problems.

[0006]

According to the present invention, a variable power optical system actuator is provided between a diaphragm and an image pickup surface,
By arranging the focus adjustment actuator between the front lens and the diaphragm, the actuator for driving the lens and the diaphragm can be downsized and can be arranged in the dead space inside the lens barrel. The shape can be reduced and the structure can be generalized. As a result, it can be applied to various camera units without increasing the shape thereof.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a transparent perspective view of a rear focus zoom lens for video which best illustrates the features of the present invention. In the figure, 1 is a lens barrel,
2 is a first group lens fixed to the front end of the lens barrel 1, 3
Is a second lens group for zooming held by the moving frame 4,
The moving frame 4 is movably fitted and supported by a guide bar 5 arranged parallel to the optical axis via a sleeve portion 4a. Reference numeral 6 denotes a guide bar 6 arranged in parallel with the optical axis, that is, the guide bar 5, and the moving frame 4 is provided on the guide bar 6.
The U-shaped groove 4b is engaged to prevent the movable frame from rotating in the direction perpendicular to the optical axis. Reference numeral 7 denotes a rack that moves integrally with the moving frame 4 in the optical axis direction without rattling, and has a structure in which a rack screw portion 7a can move around a support shaft 8 for the moving frame 4.

A zooming lens driving stepping motor 9 is fixed to the diaphragm unit 18, and a screw rod 9a which is an output shaft of the stepping motor 9 meshes with the screw portion 7a of the rack 7 without play. An afocal lens 10 is fixed to the diaphragm unit 18.

Reference numeral 11 denotes a fourth lens group for focus adjustment which is held by the movable frame 12, and the movable frame 12 is the movable frame 4 described above.
Guide bars 13, 14 arranged in parallel to the optical axis in the same manner as
It is movably supported by. This guide bar 13,1
Reference numeral 4 is fixed to the diaphragm unit 18 and the lens barrel 1.

A stepping motor 15 for driving the focus adjustment lens is fixed to the diaphragm unit 18. 1
Reference numeral 6 denotes a rack that moves integrally with the moving frame 12 in the optical axis direction without rattling, and has a structure in which a rack screw portion 16a can move around a support shaft 17 for the moving frame 12, and the rack screw portion 16a is provided with the stepping motor 15 described above. The screw rod 15a, which is the output shaft, is engaged with each other without play.

Reference numeral 18 is a diaphragm unit for integrally adjusting the amount of light, which is integrally fixed to the lens barrel 1, and has a drive unit 19, which drives the diaphragm blades 20 and the CCD.
Adjust the amount of light that hits 21.

The diaphragm unit 18 includes screw rods 9a and 15
It has recesses 18a and 18b through which a and the like pass, and these recesses 18a and 18b are provided in the peripheral portion that does not hinder the operation of the diaphragm blade 20. In addition, the above diaphragm unit 1
8 is a fitting portion 18c of the guide bars 5, 6, 13, and 14,
18d (the fitting portions for the guide bars 13, 14 are not shown), and the guide bars 5, 6, 13, 14 are provided.
Is fitted and fixed without play.

Reference numeral 22 denotes a photo interrupter fixed to the lens barrel 1, and a sensor for detecting passage of the light shielding plate 4C on the moving frame 4. Reference numeral 23 is also a photo interrupter fixed to the lens barrel 1, and the moving frame 1
It is a sensor that detects the passage of the light shielding plate 12C attached to the No. 2 sensor.

Next, the operation of the embodiment having the above configuration will be described. The light that has entered the first lens group 2 passes through the second lens group 3 for zooming, and then the afocal lens fixed to the diaphragm unit 18, which is a light quantity adjusting means, and the fourth lens group 1 for focus adjustment.
1, the image is formed on the CCD 21 which is the image pickup element, and the image is output as an electronic signal by a well-known electric circuit.

For the variable magnification adjustment, the screw frame 9a, which is the output shaft of the stepping motor 9, is rotated by a well-known electric circuit to move the moving frame 4 along the guide bars 5 and 6 through the rack 7 in the optical axis direction. Move and adjust the magnification.

Similarly, for the focus adjustment, the screw rod 1 which is the output shaft of the stepping motor 15 is formed by a well-known electric circuit.
By rotating 5a, the movable frame 12 is moved along the guide bars 13 and 14 in the optical axis direction via the rack 16 to perform focus adjustment.

Further, since the stepping motors 9 and 15 are used as these actuators, it is necessary to reset the initials. Therefore, in this embodiment, the photo interrupters 22 and 23 are used, the moving positions of the moving frames 4 and 12 are detected by the respective light shielding plates 4C and 12C, and the reference positions when the stepping motors 9 and 15 perform pulse control are set. I have found it.

This reset operation may be performed when the power of the camera set is turned on. Further, since the optical system of the present embodiment is a rear focus zoom, it is necessary to move the second lens group 3 and the fourth lens group 11 at the same time during the zooming operation. This may be arithmetically controlled by a microcomputer (not shown) so as to be placed on the cam locus of the variable-magnification optical system of the rear focus zoom.

[0019]

As described above, according to the present invention,
Since the variable-magnification optical system actuator is arranged between the diaphragm and the image pickup surface which is the CCD, and the focus adjustment actuator is arranged between the front lens and the diaphragm, it is possible to obtain a compact lens drive device without difficulty. It is possible and versatile enough to be applied to various camera units. Further, since the actuators are centrally attached in the vicinity of the diaphragm unit, not only the electrical mounting can be easily performed, but also the actuator unit can be collectively managed, which is a great effect.

[Brief description of drawings]

FIG. 1 is a transparent perspective view showing a lens driving device according to an embodiment of the present invention.

[Explanation of symbols]

1 Lens barrel 2, 3, 10, 11 Lens 4 Moving frame 9 Stepping motor (actuator for variable magnification optical system) 12 Moving frame 15 Stepping motor (focusing actuator) 18 Aperture unit 19 Aperture drive actuator 21 CCD (imaging) surface)

Claims (6)

[Claims] 1. A lens characterized in that a variable power optical system actuator is arranged between a diaphragm unit and an image pickup surface, and a focus adjusting actuator is arranged between a front lens and the diaphragm unit. Drive. 2. The lens driving device according to claim 1, wherein the focus adjusting actuator, the variable magnification optical system actuator and the diaphragm driving actuator are integrally fixed to a diaphragm unit. 3. The drive shaft of the variable power actuator and the drive shaft of the focus adjustment actuator are parallel to the optical axis and are arranged outside the operating range of the diaphragm blades. Lens drive device. 4. The lens driving device according to claim 1, wherein the diaphragm unit has a structure for mounting a fixed lens. 5. The lens driving device according to claim 1, wherein the diaphragm unit has a structure for fixing a guide bar for holding the moving frame. 6. The lens driving device according to claim 1, wherein the diaphragm unit has a structure for positioning and holding a lens barrel on the front side of the diaphragm unit and a lens barrel on the imaging side.