JPH0812322B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a camera including a lens barrel that can be extended from a camera body and distance measuring means.

B. Conventional Technology Conventionally, as this type of camera, a variable focus camera is known in which the amount of extension of the lens barrel with respect to the camera body is changed to change the focal length of the taking lens.

In this varifocal camera, the distance measuring optical system is fixed to the camera body side, and the photographing optical system is fixed and held in the lens barrel that moves in the optical axis direction with respect to the camera body. According to the result, the photographing optical system is moved along the optical axis, thereby focusing. At the time of focusing, there are a system in which the distance measuring optical system and the photographing optical system are mechanically linked and a system in which they are electrically linked. In the mechanical interlocking method, for example, when a light emitting element of a distance measuring optical system is rotated by a motor to scan an object and reflected light from the object is received by, for example, a two-divided light receiving element, and the output of each light receiving element matches. Then, the driving of the motor is stopped to stop the feeding of the photographing optical system.

In the electrical interlocking method, the subject is scanned in the same manner as described above, the rotation angle of the light emitting element is detected when the outputs of the light receiving elements match, and the photographing optical system is moved by a predetermined amount according to the rotation angle. Only feed by the motor.

C. Problems to be Solved by the Invention However, a varifocal camera, for example, a bifocal camera, has a short focus when the main lens fixedly held in the lens barrel is close to the film surface. When the lens is extended together with the lens barrel and the sub-lens is inserted in the optical axis behind the lens barrel, a long focal point is obtained. Therefore, in the case of the mechanical interlocking system described above, a photographic optical system that moves linearly and a motor that rotates rotationally or The connection with the distance measuring optical system is complicated, and the number of parts is large and a relatively large space is required. This space is a great obstacle to downsizing the camera body in a camera in which the lens barrel can be extended.

An object of the present invention is to provide a camera in which the lens barrel can be extended and the camera body can be downsized.

D. Means for Solving the Problems Describing in association with FIG. 1 showing an embodiment, the camera of the present invention has a lens barrel 9 that can be extended from the camera body and a lens barrel with respect to the camera body. A lens holding cylinder which is housed in the lens barrel 9 so as to be able to be extended together with the lens 9 and whose position can be adjusted in the axial direction with respect to the lens barrel 9, and to which the focus adjusting lens 1 of the photographing optical system is attached on the inner circumference. 3 and a distance measuring means 30 for forming an optical image necessary for detecting the focus adjustment state of the photographing optical system,
The distance measuring means 30 is kept stationary together with the lens barrel 9 so as to move integrally with the lens barrel 9 with respect to the camera body and when adjusting the position of the lens holding barrel 3 with respect to the lens barrel 9. As described above, it is housed in the lens barrel 9 to achieve the above-mentioned object. In this case, the optical axis of the photographing optical system 1 may be decentered with respect to the central axis of the lens barrel 9.

In the camera of the present invention, the optical lens included in the distance measuring means 30.
Notches 32a and 34a can be formed in the peripheral edges of 32 and 34.

E. Action When the lens barrel 9 is moved, the distance measuring means 30 also moves integrally, and the relative distance between the lens barrel 9 and the distance measuring means 30 does not change.

F. Embodiment FIG. 1 to FIG. 4 show an embodiment of the present invention.

In FIG. 1 showing a cross section of a lens barrel portion, a main lens 1 having a three-group structure is held by a holding barrel 3 having a helicoid screw 3a formed on the outer peripheral surface thereof, and the holding barrel 3 is a helicoid of a shutter base 5. It is screwed to 51. The shutter 7 is held by the rear portion 52 of the main lens 1 on the shutter base 5, and the distance measuring optical system 30 described later is provided on the holding body 53 above the main lens 1.

The shutter base 5 is integrally fixed to the inside of the cylindrical lens barrel 9, and the helicoid screw 91 engraved on the outer periphery of the lens barrel 9 is provided on the outer periphery of the lens barrel 9. Lens barrel 9 screwed with 11 helicoid screw 111
The rotation of the lens itself is blocked by a rotation blocking member provided upright on the camera body (not shown), and the movement in the direction of the optical axis is free. Therefore, when the lens barrel feed tube 11 rotates, the lens mirror correspondingly moves. The tube 9 moves along the optical axis. That is, it moves between the retracted position (Fig. 1) during short focus shooting and the protruding position (Fig. 2) during long focus shooting. In addition, 10
Indicates a cover.

Further, the cylindrical portion of the shutter base 5 to which the holding cylinder 3 is screwed
54 is an interlocking ring that is rotatable around the optical axis of the main lens 1.
13 is extrapolated. As shown in Fig. 4, the interlocking ring
A motor 15 having a gear 151 formed on 13 and meshing with a gear 131 is held by the shutter base 5. Further, a cylindrical cam 132 is connected to the interlocking ring 13.

In FIG. 4, a cam follower 171 of a lever 17, which is rotatable about a rotation center O1, is in contact with and engaged with a cam 132. A pin 172 is provided upright on the other end of the lever 17, and an engaging portion of the lever 19 which is rotatable about a rotation center O2.
191 is engaged with pin 172. Where the interlocking ring 1
3, the motor 15, the levers 17 and 19 constitute the scanning means 40.
In addition, the interlocking ring 13 is an engaging arm 13 protruding from the front of the camera.
As shown in FIG. 3, the holding cylinder 3 is engaged with the engaging arm 211 of the back adjusting ring 21 screwed to the front surface 3b of the holding cylinder 3, and the rotation of the motor 15 is performed via the interlocking ring 13. 3 is transmitted. Therefore, the interlocking ring 13, the motor 15, and the back adjusting ring 21 constitute the driving means 50 of the photographing optical system.

As shown in FIGS. 1 and 4, the distance measuring optical system 30 is
The light receiving element 31 fixedly held on the shutter substrate 5, a condenser lens 32 for converging reflected light described later on the light receiving element 31, a light emitting element 33 fixed to one end of the lever 19, and a light emitting element 33 And a light projecting lens 34 for emitting the emitted light toward a subject.

As shown in FIG. 3, a condenser lens 32 and a light projecting lens
34 is a pair of notches 32a,
with a. By providing these cutouts 32a, 34a,
The holding body 53 is downsized, and the increase in diameter of the lens barrel 9 is suppressed. In FIG. 4, both the condenser lens 32 and the light projecting lens 34 are drawn in a circular shape for simplification.

Further, as is clear from FIGS. 1 and 3, the main lens 1 is attached with its optical axis decentered below the central axis of the lens barrel 9. As a result, the storage space for the distance measuring optical system 30 can be expanded while preventing the lens barrel 9 from increasing in diameter.

The light receiving element 31 and the light emitting element 33 are an automatic focus detection circuit.
The light emitting element 33 is connected to 41, is controlled to emit modulated light, and distance measurement is performed based on the output signal of the light receiving element 31. The detection circuit 41 is an arithmetic processing unit (hereinafter, CPU) 42.
The CPU 42 is connected to the motor drive circuit 43 to control the motor 15. In addition, these detection circuit 41, CPU4
2, electric elements such as the motor drive circuit 43 are also integrally held by the shutter base 5.

The operation of the embodiment thus configured will be described.

In short-focus photography, as shown in FIG. 1, the lens barrel 9 is at the retracted position in the barrel feed barrel 11, and the focal length is determined by the main lens 1. When a shutter button (not shown) is pressed halfway, a motor drive circuit 43 operates in response to a command from the CPU 42, the motor 15 starts rotating, and the detection circuit 41 causes the light emitting element 33 to emit modulated light. In FIG. 4, when the motor 15 rotates counterclockwise, the interlocking ring 13 rotates clockwise and the lever 17 rotates counterclockwise. Lever 17
When lever 19 is rotated clockwise in conjunction with
Also rotates clockwise, and the subject is scanned by the modulated light through the light projecting lens 34. Then, the rotation of the motor 15 is transmitted to the back adjusting ring 21 via the engaging arms 133 and 211, and the holding barrel 3 rotates, whereby the main lens 1 is extended to the shutter base 5.

The modulated light emitted to the subject is reflected and enters the two-divided light receiving element 31 via the condenser lens 32. The outputs from the pair of light receiving elements 31 are input to the detection circuit 41 and subjected to known signal processing, and the point where the outputs of the respective light receiving elements 31 match is determined to be the in-focus position and a determination signal is output to the CPU 42. It Then, the CPU outputs a motor stop signal to the motor drive circuit 43 to stop the motor 15. As a result, the extension of the holding tube 3 is stopped, and the main lens 1 is controlled to a position according to the distance to the subject and focused.

Next, the lens barrel 9 in which the lens barrel feed barrel 11 rotates by a driving means (not shown) projects toward the front of the camera along the optical axis, and the sub lens 23 is inserted into the rear optical axis of the main lens 1, As shown in FIG. 2, long-focus photography becomes possible. As can be seen from FIG. 2, the main lens 1 and the distance-measuring optical system which together with the projection of the lens barrel 9 constitute the photographing optical system.
Since the driving means 50 including the scanning means 40, the scanning means 40, and the motor 15 move forward integrally, the relative positional relationship among these respective elements and systems does not change. In the case of long-focus shooting, distance measurement and focus adjustment are performed in the same manner as short-focus shooting. In both cases of short-focus shooting and long-focus shooting, the amount of extension of the main lens 1 with respect to the shooting distance is optically designed to be the same. As a result, the same cam can be used.

Although the distance measurement optical system and the photographing optical system are mechanically interlocked with each other to perform the focus adjustment in the above, the present invention can be applied to those electrically interlocked with each other. Various arrangements of the distance measuring optical system and the photographing optical system are conceivable, and the distance measuring optical system and the photographing optical system can be laterally displaced or diagonally displaced. Further, the present invention can be applied not only to the two focal points but also to a camera that can be used by switching focal lengths of three focal points or more.

G. Effect of the Invention According to the present invention, since the relative distance between the distance measuring means and the lens barrel does not change even when the lens barrel is extended from the camera body, the configuration of the distance measuring means and its surroundings is simplified, and the camera body is simplified. Can be downsized. Since the structure of the distance measuring means and its periphery is simple, even if the distance measuring means is housed in the lens barrel, the size of the lens barrel is slightly increased. In particular, if the optical axis of the photographing optical system is decentered from the central axis of the lens barrel, then the size of the lens barrel is minimized.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention and are longitudinal sectional views of the front part of the lens barrel. FIG. 1 shows a short focus, FIG. 2 shows a long focus, and FIG. Is a front view seen from the line III-III in FIG. 1, and FIG. 4 is a perspective view around the distance measuring optical system 30,
It is a figure including a block diagram of a focus detection control system. 1: Main lens, 3: Holding barrel 5: Shutter base, 9: Lens barrel 11: Lens barrel feed barrel, 13: Interlocking ring 21: Back adjustment ring, 30: Distance measuring optical system 31: Light receiving element, 33: Light emission Element 40: scanning means, 50: driving means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G03B 13/34 G03B 3/10 G02B 7/04 A

Claims (3)

[Claims] 1. A lens barrel that can be extended from a camera body, and the lens in a state in which the lens barrel can be integrally extended to the camera body and the position of the lens barrel can be adjusted in the axial direction. A lens holding cylinder housed in a lens barrel and having a focus adjusting lens of a photographing optical system attached to an inner circumference thereof, and a distance measuring unit for forming an optical image necessary for detecting a focus adjusting state of the photographing optical system. In the camera, the distance measuring means is moved integrally with the lens barrel with respect to the camera body, and is integrated with the lens barrel when adjusting the position of the lens holding barrel with respect to the lens barrel. A camera characterized in that the camera is housed in the lens barrel so as to be kept stationary. 2. The camera according to claim 1, wherein an optical axis of the photographing optical system is decentered with respect to a central axis of the lens barrel. 3. A notch formed in a peripheral edge of an optical lens included in the distance measuring means.
The camera described in the section.