JPH0763972A - Lens barrel - Google Patents

Abstract

PURPOSE:To obtain a lens barrel whose production cost can be reduced by integrating motor-driving members for zooming, and motor-driven component parts for focusing, reducing the cost of parts and simplifying assembly. CONSTITUTION:When power is supplied to the motor 11a for zooming of a motor (u) in order to operate a zoom gear 3c integrally molded with a cam barrel 3 to perform zooming, rotational force is transmitted from an output gear to the zoom gear 3c, and the cam barrel 3 is turned at a fixed position. This rotation range is regulated by a mount 1 and the zoom gear 3c. A rear group lens barrel 9 engaging with the inside cam lift 3b of the cam barrel 3 is fitted in three straight advance grooves 2a of a fixed barrel 2, and held and moved in the optical axis direction so that the projection 9a of the lens barrel 9 may slide without backlash in the cam lift 3b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel such as a zoom lens which is composed of a minimum number of parts.

[0002]

2. Description of the Related Art Conventionally, a lens barrel structure of a zoom lens for a liquid crystal projector has a lens barrel structure in which a cam barrel component uses a metal material, as in an embodiment described in Japanese Patent Application No. 4-216399. Was there.

[0003]

However, in the above-mentioned conventional example, since the cam barrel is a lens barrel structure using an Al material, the electric drive member is a separate part, or the electric drive structure for focusing is not used. Since it is difficult to set, and the structure becomes complicated, there is a lot of room to reduce the manufacturing cost including the product assembly and the component base.

The present invention has been made to solve the above problems, and makes it possible to integrate an electric drive member for zoom and an electric drive component for focusing, thereby reducing the cost of parts. It is also an object of the present invention to provide a lens barrel that can reduce manufacturing cost by simplifying assembly.

[0005]

In order to achieve the above object, the lens barrel of the present invention is a two-group zoom lens barrel comprising a front lens group and a rear lens group according to claim 1, wherein a mount and a front lens group are provided. A rear group lens holding frame that is movable only in the optical axis direction by a fixed portion coupled to the moving guide and an optical axis direction guide unit provided in the fixed portion, and a front group lens for focusing and zooming. A holding frame is provided in the fixed portion by a front group moving guide, which is capable of moving in the optical axis direction and has a front unit moving frame provided with a feeding means for focusing, and a predetermined range outside the fixed portion. There is a cam barrel that is rotatably held inside, and a projection having a lead inside the cam barrel and a projection from the rear lens group holding frame are fitted to each other to secure the rear lens group holding frame. Hold it, and by rotating the cam barrel, the rear lens group holding frame moves in the optical axis direction. And means for moving, the front group moving frame,
A cam barrel fitted with a protrusion on the outside of the cam barrel and held by radial fitting, and provided with means for moving the front group moving frame in the optical axis direction by the rotation of the cam barrel. In addition, according to claim 2, the cam cylinder is formed by integrally forming a component for electric drive, and further, according to claim 3,
In a cam cylinder and a mount formed of plastic, a drive member rotatable at a fixed position is thrust-regulated and radially fitted to the mount formed by plastic for focusing, and the drive member is moved in focus. It has a configuration in which it is key-connected to the device.

[0006]

According to the present invention, in order to minimize the number of parts constituting the zoom lens, the cam barrel is formed into a moldable component shape, and the front barrel guide 4 is attached to the fixed barrel which is radially fitted to the cam barrel. And a straight groove 2a for the rear group. Further, by forming a large gear 3c integrally with the cam barrel for the electric drive of the zoom, and enabling a lens barrel configuration in which the focus gear and the focus key can be integrated for the electric drive of the focus, all the components are made of plastic. It has become possible to significantly reduce the manufacturing cost by reducing the parts cost and improving the ease of assembly.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention and is a cross-sectional view that best shows the features of the present invention. In FIG. 1, L1 is a front lens group and L2 is a rear lens group, a two-group zoom lens. . Reference numeral 1 is a mount made of a plastic material attached to the liquid crystal projector main body, and a fixed barrel 2 is a fixed component having a light shielding means 2a against ghost on the mount side and coupled to the mount 1 with a screw. Axial guide groove 2
It has b and is fitted in diameter. In front of the fixed tube 2,
A straight advancing ring 4 having three guides 4a engaged with the projections of the straight advancing key 5b on the front group moving ring 5 and further having a rotation restricting projection is screwed.

A cam barrel 3 is radially fitted to the outer circumference of the fixed barrel 2, a front group moving ring 5 is radially fitted to the outer circumference of the cam barrel 3, a thrust-regulated projection 3a, and a rear portion is fitted to the inner circumference. A cam projection 3b for moving the group lens and a zoom gear 3c as a component for electric driving are provided on the rear outer peripheral portion, and the focus gear 7 is further provided.
Is provided with a protrusion 3d for preventing the swinging of the.

A helicoid screw 5c for focusing movement is attached to the outer periphery of the front lens group moving ring 5 to form a helicoidal connection with the focus ring 6, and the front lens barrel 8 is screwed to the focus ring 6. The focus ring 6 has three stationary rotation rings 7 key-connected to each other, which are radially fitted to the outer periphery of the mount 1 and are engaged with a circumferential groove whose thrust is restricted. The rotation of the focus ring 6 is restricted by the focus stopper 10. Zoom motor 11
a, the motor u for the focusing motor 11b is constituted by the main plate 12 (separated into upper and lower sides in the sectional view), and is fixed to the mount by screws.

Next, in the above structure, the zoom gear 3c formed integrally with the cam barrel 3 is zoomed in. For this reason, the power of the zoom motor 11a of the motor u is turned on so that a rotational force is applied from the output gear to the zoom gear 3c. When transmitted, the cam barrel 3 rotates at a fixed position. This rotation range is
It is defined by the mount 1 and the zoom gear 3c. The rear group lens barrel 9 fitted to the inner cam lift 3b of the cam barrel 3 is fitted into the three straight-moving grooves 2a of the fixed barrel 2,
In addition, the projection 9a from the rear lens barrel 9 is slidably held by the cam lift 3b and moves in the optical axis direction.

Simultaneously with the rotation of the rear group lens barrel 9, the projection 3a on the outer periphery of the cam barrel 3 and the cam 5a on the inner side of the front group moving ring 5 are provided.
The front group moving ring 5
The front group moving ring 5 moves in the optical axis direction by the straight-moving key 5b and the guide guide 4a of the straight-moving ring 4. A helicoid screw 5c is provided on the outer peripheral portion of the front group moving ring 5, and the front group lens barrel 8 is coupled to the helicoid screw 5c. The front group moving ring 5 is helicoidally connected to the focus ring 6.

As described above, the movement in the optical axis direction for focusing can be performed manually. In the electric drive of the focus, the rotational force from the output shaft of the focus motor 11b of the motor u is the focus gear 7a.
Be transmitted to. Stationary rotating ring 7 to which rotational force is transmitted
Is coupled to the key 7b at three points with the focus ring 6, and the rotational force is transmitted to perform focusing. The stationary rotating ring 7 is a protrusion 7 fitted in the circumferential groove of the mount 1.
In order to prevent thrust regulation and rocking, it is engaged with the mount c and is radially fitted to the mount 1, and rocking is prevented by the outer peripheral projection 3d of the cam barrel. At that time, the focus rotation is restricted by the stopper screw 10 provided with a cutout in the stationary rotation ring 7.

[0013]

As described above, by changing the material of the cam barrel from metal (Al) to plastic, it is possible to integrally form a large gear for electrically driving the zoom. Furthermore, by enabling a lens barrel configuration that allows the focus gear and focus key of the electric drive components of the focus to be integrally molded, the lens barrel components can be made of all plastics, which reduces the cost of components and ease of assembly. It was possible to make an improvement, and the manufacturing cost could be significantly reduced.

By using the all plastic material, it is possible to reduce the coupling of parts by screw coupling, reduce the load torque of the lens barrel for focus / zoom, and facilitate the setting of the electrically driven actuator.

[Brief description of drawings]

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

FIG. 2 is a schematic view of the AA cross section of FIG.

FIG. 3 is a perspective view of a stationary rotating ring.

[Explanation of symbols]

 L1 front lens group L2 rear lens group 1 mount 2 fixed tube 2a light-shielding line 2b guide groove 3 cam tube 3a cam tube projection 3b rear group cam lift 3c zoom gear 3d outer circumferential projection 4 straight advance ring 5 front group moving ring 5a front group cam lift 5b straight advance key 6 Focus ring 7 Stationary rotation ring 7a Focus gear 7b Key 7c Fitting protrusion 8 Front group lens barrel 9 Rear group lens barrel 10 Stopper screw 11a Motor (for focus) 11b Motor (for zoom) 12 Main plate

Claims (3)

[Claims] 1. In a two-group zoom lens barrel including a front group and a rear group, a fixed part coupled to a mount and a front-group moving guide, and an optical axis guide means provided on the fixed part A rear lens group holding frame movable only in the axial direction and a front lens group holding frame for focusing / magnifying are provided in the fixed portion by a front lens group moving guide, which enables movement in the optical axis direction, Further, there is a front group moving frame provided with a feeding means for focusing, and a cam barrel rotatably held within a predetermined range outside the fixed portion, and a projection having a lead inside the cam barrel. And means for moving the rear group lens holding frame in the optical axis direction by fitting the projection from the rear group lens holding frame, holding the rear group lens holding frame, and rotating the cam barrel. The front group moving frame fits with the protrusion on the outside of the cam barrel,
And it is held by a radial fit, and by the rotation of the cam barrel,
A lens barrel comprising a cam barrel provided with means for moving the front lens group moving frame in the optical axis direction. 2. The lens barrel, wherein the cam barrel is integrally formed with a component for electric drive. 3. A drive member, which is rotatable at a fixed position during electric drive for focusing, is thrust-regulated and diameter-fitted to the cam barrel and a mount formed of plastic, and
The lens barrel is characterized in that the driving member is keyed to a device for focusing movement.