JPS62124537A - Two-focus camera - Google Patents

Abstract

PURPOSE:To simplify a two-focus switching mechanism and to reduce its cost and to obtain a sharp and stable picture in telephoto/wide-angle switching operation by providing a switching drive member which functions to operate a master lens moving mechanism and a converter lens moving mechanism by the same system. CONSTITUTION:When the focus is switched from the wide angle side to the telephoto side, a motor is driven with a telephoto/wide-angle signal from a camera body 1 to put a main driving part in operation, so that the switching drive member 4 rotates through the gear of a telephoto/wide-angle driving system. A moving frame 6 moves toward a body side with a nut 7 fixed to the moving frame at speed corresponding to the rotational speed of the switching drive member 4 and the pitch of a screw part 4c until it contacts the part C of a fixed ring 3. At the same time, the rotational operation of the gear part 4b of the switching drive member 4 is transmitted to a gear 16 by the intervention of a gear 15. The rotational operation of the gear 16 is transmitted to a converter lens frame 14 with the frictional force generated between the contacting surfaces of the gear and converter lens frame 14 with the pushing force of a slit plate 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bifocal camera, in particular a master lens,
The present invention also relates to a bifocal camera having a focus switching mechanism by moving a converter lens.

Conventionally, in bifocal cameras that switch between telephoto and wide-angle, the switching between telephoto and wide-angle is controlled from the camera body.
Transfer the master lens through the body! lJ mechanism and converter lens moving mechanism to displace the master lens in the direction of the light flux of the master lens, and to displace the converter lens from the inserted position into the light flux of the master lens and from the inserted position to the retracted position, respectively. A device having two independent drive transmission means is known.

However, using independent drive transmission means for the master lens moving mechanism and the converter lens moving mechanism results in a complicated structure and increased cost.

The purpose of the present invention is to simplify the conventional bifocal switching mechanism and to
Another object of the present invention is to provide a bifocal camera that can reduce the cost of the switching mechanism and provide a clear and stable image during telephoto and wide-angle switching operations.

I bottom The present invention will be explained below with reference to one illustrated embodiment.

In the present invention, the master lens moving mechanism is composed of, for example, a threaded portion of the switching drive member, a nut portion screwed into the threaded portion, a moving frame, a lens set board, a master lens frame, etc. The moving mechanism is
For example, it is composed of a gear portion of a switching drive member, a gear meshing with the gear portion, a converter lens frame, and the like.

Further, the slip mechanism provided in the converter lens moving mechanism is composed of, for example, a screw and a slip plate.

In FIG. 1, a lens substrate 2 is fixed to a camera body 1. As shown in FIG. A fixing ring 3 is fixed to the lens substrate 2, and a switching drive member 4 is rotatably fitted to the lens substrate 2. The switching drive member includes a gear portion 4] and a gear portion 4b.
, and a threaded portion 4C. The gear part 4a
is meshed with a gear 5 that transmits the rotational operation of a motor (not shown) installed on the main body side and driven by a telephoto/wide-angle signal. Further, the gear portion 4)) meshes with gears 15 and 16. The gear 16 contacts the rotatable and slidable converter lens frame 14, and is penetrated by a screw 18 fixed to a part of the fixing ring 3 together with the converter lens frame and the slip plate 17. Further, the gear 16 and the converter lens frame 14 are pressed by a slip plate 17. Further, the screw portion 4c is threaded into a nut portion 7 fixed to a part of the movable frame 6, which displaces the movable frame 6 to which the lens cellar 1 and substrate 9, which will be described later, are fixed, in the direction of the optical axis of the master lens. A shutter section 8 is fixed to the end of the movable frame 6 on the image plane side, and a lens set board 9 is fixed to the end of the movable frame 6 on the object side. Bin 9 on lens set board 9
A and bottle 9b are installed. The bottle 9a is always held by a compression spring 10.

It fits into a boss 11 that is pressed in the image plane direction indicated by the arrow in the figure. The boss 11 is fixed to a master lens frame 12, and a master lens group 13 is attached to the master lens frame. The boss 11 is built into the camera body 1,
It is driven by a lever 21 extending from a known AF drive section (not shown).

The focus is adjusted by adjusting the position of the master lens group 13. Also, the bottle 9b is the master lens frame 1.
2 into the notch 12a of the master lens frame 12.
The rotation is stopped.

In FIG. 2, the gear portion 4b of the switching drive member 4 and the gear 1
5. A gear 16 disposed coaxially with the converter lens frame 14 meshes with each other to form a gear train. The gear 16 and the converter lens frame 14 are arranged side by side on the axis of the screw 18.

The gear 16 and the converter lens frame 14 are provided on the screw 18 between the head of the screw and the gear 16.

For example, they are rotatably and slidably fitted with a slip plate 17, which is a wave-shaped washer, interposed therebetween, and are pressed by the slip plate. A converter lens group 20 is attached to the converter lens frame 14. Further, a portion A is formed in a part of the fixing ring 3, with which the converter lens frame 14 comes into contact.

In FIG. 3, the guide bottle 1 fixed to the lens substrate 2
9 passes through the notch 3a of the fixed ring 3 and fits into the moving frame hole 6a.

Hereinafter, the operation will be explained based on this configuration. When switching the focus from the wide-angle to the telephoto position, a motor (not shown) is rotated by the telephoto/wide-angle signal from the camera body 1, which activates the main body drive part, and the switching is performed via the gear 5 of the telephoto/wide-angle drive system! S@The moving member 4 rotates. The movable frame 6 is moved toward the object side at a speed corresponding to the rotational speed of the switching drive member 4 and the pitch of the threaded portion 4C by the nuts 1-7 fixed to the movable frame until it contacts the 0 part of the fixed ring 3. Moving. At the same time, the rotational movement of the gear portion 4b to the switching drive member is transmitted to the gear 16 via the gear 15. The rotational movement of the gear 16 is controlled by a slip plate 1 on the contact surface between the gear and the converter lens frame 14.
The frictional force generated by the pressing force 7 is transmitted to the converter lens frame 14.

The converter lens frame rotates in conjunction with the rotation of the gear 16 until it comes into contact with part A of the fixing ring 3. Moving frame 6
When it comes into contact with the 0 part of the fixed ring 3, the load on the telephoto and wide-angle drive system increases, and a load detection device using a known TL star gear or clutch stops the main body drive part (not shown), and the switching drive member 4 stops. Rotation stops. The converter lens frame 14 is in contact with the fixed ring section A before the shifter frame 6 contacts the 0 section of the fixed ring 3, and the rotation operation has been completed. The converter lens group 20 has moved to a position where it is inserted into the light beam of the master lens group 13.

The converter lens moving mechanism includes a converter lens frame 14
However, until the switching drive member 4 stops rotating while it is in contact with the A portion of the moving frame 6, it slips due to the above-mentioned slip mechanism.

When the focus is switched from the telephoto to the wide-angle position, the motor (not shown) on the main body rotates in the reverse direction, and the movable frame 6 moves to the B part of the fixed ring, contrary to the case where the focus is switched from the wide-angle to the far position. The master lens group 20 moves to a position removed from the light beam of the master lens group 13. Similarly to the above-described switching from the wide-angle to the telephoto position, when the movable frame 6 contacts the B part of the fixed ring 3, a known load detection device of the main body detects that the main body rIjA (not shown)
! l] portion stops, and the rotation of the switching drive member 4 stops. Converter lens transfer! The IJ mechanism is slipped by the slip mechanism until the switching drive member 4 stops rotating with the converter lens frame 14 in contact with the D portion of the fixed ring 3.

According to the present invention, a switching drive member having a function of operating the master lens moving mechanism and the converter lens moving mechanism in the same system is provided.

It has become possible to significantly simplify the conventional bifocal switching mechanism and reduce the cost of the product, and by providing a slip mechanism in the converter lens moving mechanism and a part on the fixed ring where the converter lens frame comes into contact, the master The optical axis precision of the lens and converter lens is improved and optical performance is stabilized. In addition, during telephoto and wide-angle shooting, the movable frame is mounted on the end of the fixed ring, which stabilizes the lens position and film surface position, and has the effect of improving focus and control precision.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view at a wide-angle position of a bifocal camera showing an embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional side view of the bifocal camera of the present invention at a telephoto position. l...Camera body, 2...Lens board, 3...
...Fixing ring, 4...Switching drive member, 4b...
・Gear part, 4c...Screw part, 6...Movement frame, 1
3... Master lens group, 14... Converter lens frame, 17... Slip plate, 20... Converter lens group

Claims (1)

[Claims] 1. A bifocal lens characterized by being provided with a master lens moving mechanism, a converter lens moving mechanism, and a switching drive member for driving the master lens moving mechanism and the converter lens moving mechanism in the same system. camera. 2. 2 as set forth in claim 1, characterized in that the converter lens moving mechanism is provided with a slip mechanism.
focus camera. 3. The bifocal camera according to claim 1, wherein the master lens moving mechanism is provided with a guide section. 4. A master lens moving mechanism, a converter lens moving mechanism, a switching drive member for driving the master lens moving mechanism and the converter lens moving mechanism in the same system, and an abutting portion that comes into contact with the converter lens frame. A bifocal camera.