JPH0610717B2 - Camera focal length changing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a focal length changing device capable of switching a magnification of a camera.

[Background of the Invention]

A large number of patents and utility models have been filed for variable magnification cameras (variable magnification cameras) capable of performing long focus photography and short focus photography. In most of the variable magnification cameras that have been announced so far, the zoom mechanism and lens switching mechanism are arranged around the lens mirror surface, so the size of the camera is increased, and the magnification change operation is performed around the lens barrel. Therefore, there is a drawback in that the mechanism for shading becomes complicated and the cost becomes very high because of the large movement in the front-back direction.

Therefore, the present inventor has developed a technology for a compact and low-cost variable magnification camera that eliminates the drawbacks of the conventional variable magnification camera as described above, and has already proposed this new variable magnification camera.

6 (a) and 6 (b) show the structure of the variable magnification camera proposed by the present inventor, and FIG. 6 (a) shows the state of each part of the camera at the time of short-focus photography, FIG. 6 (b) shows a state at the time of long-focus photography.

In FIG. 6, 1 is a camera body and 2 is a back cover.
Inside the camera body 1, a battery chamber 1a, a spool chamber 1d,
A patrone chamber 1e is formed, and a long focus shooting aperture 1f and a short focus shooting aperture 1g are provided adjacent to each other along the traveling direction of the film F. The taking lens of the convex lens system composed of the lenses 17 to 19 is supported by the lens frame 16, and the lens frame 16 is fixed in the lens barrel portion 1c of the camera body 1. A front lens 22 that can move laterally in the lens barrel portion 1c is provided in front of the taking lens.
2 is fixed to the movable frame 21. Reference numeral 23 is a movable mirror used during long-focus shooting, 24 is a converter lens used during long-focus shooting, and 25 is a fixed mirror used also during long-focus shooting.

Movable mirror 23 and front lens 2 during short-focus photography
2 becomes the state as shown in FIG. 6 (a), and the photographing lenses 17-1
The subject light flux that has passed 9 is a short-focus shooting aperture 1g.
Image on. On the other hand, during long-focus photography, the movable mirror 23 and the front lens 22 are in the state shown in FIG. 6 (b), and the subject light flux is the front lens 22, the photographing lenses 17 to 19, the movable mirror 23, the converter lens 24, and the fixed mirror 2.
5. An image is formed on the aperture 1f through the Z-shaped optical path of the short focus shooting aperture 1f.

One of the characteristics of the variable power camera having the above-described structure is that the front lens 22 formed of a concave lens is provided in front of the taking lens to prevent the camera from becoming large during long-focus shooting. .

That is, in general, long focal length photography of a variable magnification camera is possible by installing only the converter lens 24 in the optical path behind the taking lenses 17 to 19, but in that case, the converter lens 24 is used as the focal position of the taking lenses 17 to 19, that is, the aperture. It is necessary to install it considerably ahead of the position equivalent to 1 g, but it is impossible to place the converter lens by interfering with the movable mirror 23 as is apparent in FIG. The taking lens 1 described above
It has been laid out at the focal positions of 7 to 19.

Therefore, at the time of long-focus photography, by inserting the concave lens 22 in front of the taking lenses 17 to 19 and shifting the combined focus position to the rear of the above-mentioned converter lens 24,
It was configured to focus on the long focus aperture 1f.

As described above, in the camera proposed by the present inventor,
A compact variable magnification camera can be realized by providing a concave lens type front lens 22 in addition to the movable mirror 23, the fixed mirror 25, and the converter lens 24, but the camera has the following drawbacks. Therefore, it was not always preferable as a practical machine.

(i) Both the front lens 22 and the converter lens 24 need to be a combination lens of two or three lenses or an aspherical lens in order to remove chromatic aberration.
It is not preferable to use a combination lens or an aspherical lens because the lens cost will be considerably high and the camera price will be high.

(ii) Since the thickness of the camera is increased by the thickness of the support mechanism of the front lens 22, portability is deteriorated.

(iii) Since the front lens 22 and its support mechanism are located in front of the taking lens, the interlocking mechanism of the front lens 22, the movable mirror 23, and the finder section becomes large and complicated, resulting in high cost and heavy camera weight. Become.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and includes an incident optical path for entering light, a first guide optical path for guiding the light incident from the incident optical path to a first imaging surface, and A second guide light path for guiding the light incident from the incident light path to the second image forming surface, which is shorter than the first guide light path, and a selection for selecting the first guide light path and the second guide light path. Means, a first lens system provided in the incident optical path, and a first lens system that moves in response to the selection means selecting the second guide optical path and shortens the focal length of the first lens system. It is intended to provide a focal length changing device for a camera, which is provided with two lens systems and can be made thin, compact and lightweight, and can be constructed at a low cost.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIGS. 1 (a), 2 (a) and 3 (a) are schematic views showing the state of the variable magnification camera of this embodiment during short-focus photography,
FIG. 2B, FIG. 2B, and FIG. 3B are schematic views showing the state of the variable magnification camera of this embodiment at the time of long-focus shooting.

In FIG. 1, 101 is a camera body, and the camera body 101 includes a cartridge chamber 101a and a spool chamber 101.
b, a movable mirror receiving hole 101c, a short focus shooting aperture 101d, a long focus shooting aperture 101e, and a light shielding portion 101f for blocking a part of ineffective light flux to the long focus shooting aperture. Reference numeral 102 is a spool for winding the film housed in the spool chamber 101b, 103 is a roller plate for auto loading pressed against the outer peripheral surface of the spool 102, 104 and 105 are batteries,
Reference numeral 106 is a camera cover including a back cover. On the front side of the camera cover 106, an opening 106a for photographing is provided so as to penetrate therethrough. 107 is a condenser for a strobe device, 108 is a fixed mirror which constitutes one element of the optical path for long focus photography,
Is.

The movable mirror 109 that fits into the movable mirror hole 101c of the camera body 101 is fixed to one frame body portion 124A of the V-shaped movable frame 124 that rotates about an axis 124a (see also FIG. 4). Therefore, the movable mirror 109 is adapted to be fitted into the movable mirror hole 101c of the camera body 101 at the time of short-focus photographing (FIG. 1).

The movable frame 124 is configured by integrating two frame bodies 124A and 124B, which are arranged in a V shape with each other, as clearly shown in FIG. 4, and is provided with a shaft 124a. The movable mirror 1 is provided in the opening of the body portion 124A.
09 is fitted, while the opening 12 of the other frame body portion 124B is fitted.
4b is opened as a translucent opening. Frame body part 124
B and the longitudinal direction located on the tip side (parallel to the axis 124a)
The frame member 124d is arranged in the lateral direction (shaft 12) of the frame body portion 124B.
4a has a width wider than that of the frame member 124c in the direction perpendicular to 4a), and the frame member 124d is used as a light blocking member for blocking an ineffective light beam to the long focus shooting aperture 101e during long focus shooting. To be The frame member 124d
The thickness of the light blocking member (that is, the light blocking member) becomes thinner toward the tip of the frame portion 124B. Further, as will be described later, the opening 124b serves as a light-transmitting window for allowing light transmitted from the photographing lens (reflected light flux from the subject) to pass toward the movable mirror 109 during long-focus photographing.

A photographic lens composed of Tessar type lenses 116 to 118 is arranged facing the opening 106a of the camera cover 106, and the photographic lens is fixed in the lens barrel 115. This taking lens is a long-focus lens and is used alone during long-focus shooting. Lens barrel 1
Reference numeral 15 is connected to an autofocus mechanism that is not fixed and is movable in the front-back direction of the camera.

As shown in FIG. 5, the front end surface of the lens barrel 115 has a frame-shaped light-shielding mask 11 that shields both side edges of the lens 118.
9 is attached.

A shutter 113, which also serves as diaphragm blades, is arranged on the base plate 114 behind the lens barrel 115, and the shutter 113 is operated by a known exposure control device.

A movable frame 11 is provided behind the shutter 113 and the main plate 114.
A converter lens mounted at 0 is arranged.
This converter lens is a convex lens composed of lenses 111 and 112, and is inserted in the rear of the taking lens only in short-focus photographing.

2 and 3, the movable frame 124 of the movable mirror 109 is shown.
And a drive mechanism for driving the movable frame 110 of the converter lens.

As shown in FIGS. 2A and 2B, the shaft 11 of the movable frame 110 is
0a is aligned with the axis 122a of the sector gear 122, and the movable frame 110 and the sector gear 122 can rotate about the same axis. The movable frame 110 has a short arm 110b in addition to the part to which the lenses 111 and 112 are attached.
A spring 123 is applied to 10b to urge the movable frame 110 clockwise in the drawing. A pin 122c that engages with the movable frame 110 is provided on the surface of the sector gear 122 so as to project.

Teeth 120b that mesh with teeth 122b of the sector gear 122
Is provided so as to be rotatable around the axis 120a thereof, and the movable frame 124 is arranged such that its axis 124a is aligned with the axis 120a of the sector gear 120. A spring 121 is hooked on the movable frame 124 to urge the movable frame 124 clockwise in the drawing. A pin 120c that engages with the movable frame 124 is provided on the surface of the sector gear 120 so as to move with the sector gear 120 via the pin 120c when the sector gear 120 is rotated counterclockwise in the drawing. The frame 124 and the frame 124 rotate together around the shaft 120a.

FIGS. 3 (a) and 3 (b) schematically show a drive mechanism for driving the sector gear 120. In the figure,
201 is a motor, 202 is a sun gear having a shaft 202a driven by the motor 201, and 204 is a shaft 202a.
An arm 203 is fixed to the armature 203, and a planetary gear 203 is rotatably supported near the tip of the arm 204.
4b is a finger formed on the tip of the arm 204, 2
Reference numeral 05 is a fork drive gear that transmits power to a fork (not shown) when meshed with the planetary gear 203, and 206 is a spool drive gear that transmits power to the spool 120 when meshed with the planetary gear 203.

On the other hand, the sector gear 120 is provided with a pin 120e protruding from its outer peripheral portion, and a known toggle spring 208 is locked to the pin 209 and the pin 120e projecting from the structural member of the camera. As is well known, when the toggle spring 208 is deformed by applying an external force from a certain first stable state, it generates a resistance force (positive resistance force) against the external force up to a certain state, but in a certain state. Is a spring that suddenly generates a negative resistance force (that is, a resistance force in the same direction as the external force) and rapidly reaches the second stable state. The resistance force changes from positive to negative. The state of conversion is called the dead point. In the state of FIG. 3 (a), the toggle spring 208 urges the sector gear 120 counterclockwise to abut against the stopper 211 and prevents the sector gear 120 from rotating clockwise. Figure (b)
In this state, the toggle spring 208 urges the sector gear 120 clockwise to bring the sector gear 120 into pressure contact with the other stopper 210.

On the shaft 120a of the sector gear 120, a short arm 120d protruding in the opposite direction to the sector gear main body is formed integrally with the shaft 120a, and the tip of this arm 120d is the finger 204a of the tip of the arm 204 of the planetary gear mechanism. And 204b between the fingers 204a and 2b
It is adapted to engage with either one of 04b.

Next, in the structure as described above, the movable mirror 109 and the converter lenses 111 and 11 in the camera of this embodiment are arranged.
The operation of No. 2 will be described in relation to the operation of the camera.

First, a case where a camera operator operates an operation member of the camera to switch the camera from long-focus shooting to short-focus shooting will be described. When an electrical command to switch the camera from long-focus shooting to short-focus shooting is issued from the information processing circuit in the camera, a viewfinder (not shown) is switched by a mechanism (not shown) and the short-focus shooting switch is turned on. The motor 201 is rotated clockwise in the state of FIG. 3 (b). For this reason, the sun gear 202 and the arm 204 are also rotated in the clockwise direction, so that the planetary gear 203 is separated from the fork drive gear 205 that has been meshed with the planetary gear 203 until then, and the arm 204 is moved to the position shown in FIG. ) Descends. When the arm 204 descends, the finger 20
4a and the arm 120d of the sector gear 120 are engaged with each other, the arm 120d is pushed down by the fingers 204a, so that the sector gear 120 rotates counterclockwise about its axis 120a while resisting the resistance of the toggle spring 208. Be moved. Then, when the dead point of the toggle spring 208 is passed, the sector gear 120 is driven by the force of the toggle spring 208.
Is rapidly rotated counterclockwise to reach the state of FIG. 3 (a), and the sector gear 120 contacts the stopper 211 and is positioned.

When the sector gear 120 is thus rotated counterclockwise, the pin 120c protruding from the sector gear 120 is also rotated counterclockwise, so that the movable frame 1 of the movable mirror 109 is rotated.
24 is also rotated counterclockwise around the shaft 124a thereof together with the sector gear 120 via the pin 120c. When the gear 120 comes into contact with the stopper 211 and stops, the movable frame 124 stops in the states shown in FIGS. 1 (a) and 2 (a), and the movable mirror hole 101c of the camera body 101 is stopped.
Is blocked by the movable mirror 109, while the movable mirror 10
By 9, the short focus shooting aperture 101d and the long focus shooting aperture 101e are completely separated.

On the other hand, when the sector gear 120 rotates counterclockwise from the state of FIG. 3 (b) to the state of FIG. 3 (a) as described above,
Since the sector gear 122 in the state of FIG. 2 (b) rotates clockwise about its own shaft 122a,
The movable frame 110, which is connected by the force of the sector gear 122 and the spring 123, is also rotated clockwise about its own shaft 110a and finally reaches the state of FIG. 2 (a).
Therefore, the converter lenses 111 and 112 attached to the movable frame 110 are also changed from the state of FIG. 1 (b) and FIG. 2 (b) to the state of FIG.
The converter lenses 111 and 112 are positioned behind the photographing lenses 116 to 118 by switching to the states of (a) and FIG. 2 (a) (that is, the short-focus photographing state).

On the other hand, as described above, the arm 204 descends and the planetary gear 2
When 03 meshes with the spool drive gear 206, the rotation of the motor 201 is transmitted to the spool drive gear 206 via the sun gear 202 and the planetary gear 203, so that the spool 102 is rotated and the film is unwound from the film spool. Then, it is positioned on the short focus imaging aperture 101d.

After the preparation for the short focus shooting is made as described above, the shooting can be performed.

Switching from short-focus photography to long-focus photography is performed in the reverse operation. That is, the motor 201 is operated by the command from the information processing circuit or the operation of the manual button or the like.
When rotated counterclockwise in the state of (a), the arm 204 of the planetary gear mechanism rotates counterclockwise around the shaft 202a in the state of FIG. 3 (a), and the finger 204b rotates the arm 120d of the sector gear 120. And the sector gear 120 is rotated clockwise through the arm 120d. Therefore, the movable frame 124 connected by the force of the sector gear 120 and the spring 121 also rotates clockwise about the shaft 124a thereof, so that the movable frame 124 and the movable mirror 109 are moved from the state of FIG. 1 (a). The state shifts to the state shown in FIG. 1 (b) and FIG. 2 (b). Further, since the sector gear 122 is driven counterclockwise around the shaft 122a, the movable frame 110 connected to the sector gear 122 by the force of the spring 123.
Also rotates counterclockwise about its axis 110a and finally shifts to the state of FIG. 1 (b) and FIG. 2 (b).

When the movable frame 124 reaches the state of FIG. 1 (b), the movable frame 1
The frame body portion 124B (FIG. 4) on the front end side of 24 is substantially horizontal, and the frame member 124d, that is, the light shielding member 124d and the opening 124b are positioned substantially horizontally behind the taking lens. The frame member 124d is the camera body 101.
Since it is arranged at a position close to the movable mirror hole 101c, the light flux A that obliquely enters the photographing lens is
Therefore, the non-effective light flux does not enter the long-focus imaging aperture 101e.

At the same time that the movable frame 124 moves from the state of FIG. 1 (a) to the state of FIG. 1 (b), the movable frame 110 also moves from the state of FIG. 1 (a) to the state of FIG. 1 (b). Therefore, during long-focus shooting, the converter lenses 111 and 112 are excluded to the outside of the optical path (on the back side of the movable mirror 109), and the light flux of the subject is taken by the shooting lenses 116 to 118 and the aperture 124 of the movable frame 124.
b through the movable mirror 109 and the fixed mirror 108
The long-focus photographing aperture 101e is reached through the shaped optical path, and as a result, long-focus photographing can be performed. In this case, in the camera of the present invention, both side edges of the frame-shaped light-shielding mask 119 attached to the front end surface of the lens barrel 115 have the fifth edge.
As shown in the drawing, since the lens 118 is extended so as to cover both side edges, the effective luminous flux passing through the taking lenses 116 to 118 is limited to the angle range of θ shown in FIG. 1 (b). The ineffective light flux that tries to reach the long-focus imaging aperture 101e without passing through the movable mirror 109 can be reduced also in the photographing lens, and as a result, the frame member 124d serving as a light shielding member for the ineffective light flux. In combination with the use of (1), it is possible to completely prevent the ineffective light flux from reaching the aperture for long-focus imaging without going through the normal optical path during long-focus imaging.

As described above, in the camera of the present embodiment, the taking lens is the lens for long-focus photography, and at the time of long-focus photography, the light-shielding mask 119 at the tip of the lens barrel and the frame member (light-shielding member) 124d behind the taking lens are used for long-length photography. Since the ineffective light flux is prevented from entering the aperture for focus shooting, a convex converter lens that works in conjunction with the movable mirror 109 is inserted behind the shooting lens during short focus shooting. It is not necessary to provide such a front lens, and as a result, it is possible to realize a variable magnification camera which is thin and lightweight, has good portability, and is inexpensive to manufacture.

That is, in more detail, according to the above-described embodiments, a camera that can achieve the following effects is provided.

(a) Since it is not necessary to provide a front lens, the camera is thin and easy to carry.

(b) Since a large-sized interlocking mechanism that interlocks the front lens with the movable mirror and the finder mechanism is not required, the camera can be made lightweight and the manufacturing cost can be reduced.

(c) Since the light blocking member 124d for blocking the ineffective light flux at the time of long-focus shooting is integrally formed with the movable mirror support frame 124, it is not necessary to provide a complicated interlocking mechanism for the light blocking member. It is possible to prevent an increase in manufacturing cost and an increase in manufacturing cost. In addition, the movable regions of the converter lenses 111 and 112 and the movable mirror 109
Since it overlaps with the movable area of, the camera can be prevented from becoming large due to the movable converter lens.

In the above embodiments, the photographing lens 116 is opened from the opening 106a.
~ 118 arranged optical path corresponds to the incident optical path of the present invention,
The optical path from the movable mirror 109 to the long-focus imaging aperture 101e via the fixed mirror 108 corresponds to the first guiding optical path of the present invention, and the optical path from the converter lenses 111 and 112 to the short-focus imaging aperture 101d. Corresponds to the second guiding optical path of the present invention, the movable mirror 109 corresponds to the selecting means of the present invention, the taking lenses 116 to 118 correspond to the first lens system of the present invention, and the converter lenses 111 and 112 correspond to. It corresponds to the second lens system of the present invention.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a focal length changing device for a camera which can be made thin, compact and lightweight, and can be constructed at a low cost, and its effectiveness is extremely high.

[Brief description of drawings]

FIG. 1 (a) is a schematic diagram showing the state of the camera of the embodiment of the present invention during short-focus shooting, and FIG. 1 (b) shows the state of long-focus shooting with the camera of FIG. 1 (a). Schematic diagram shown, second
FIGS. 2 (a) and 3 (a) are schematic views showing the state of the main part mechanism at the time of short-focus photography in the camera of FIG. 1, and FIGS. 2 (b) and 3 (b) are FIG. FIG. 4 is a schematic view showing a state of a main part mechanism at the time of long-focus photographing in the camera of FIG. 4, FIG. 4 is a perspective view showing a movable frame of a movable mirror equipped in the camera of FIG. 1, and FIG. Front view of light-shielding mask installed in camera, 6th
FIG. 6 (a) shows a state of the camera proposed by the present inventor during short-focus shooting, and FIG. 6 (b) shows a state of long-focus shooting with the camera of FIG. 6 (a). Fig. 1 ... Camera body, 2 ... Back cover, 1f ... Aperture for long focus shooting, 1g ... Aperture for short focus shooting, 17-19 ... Shooting lens, 22 ... Front lens, 23 ... Movable mirror, 24 ... Converter lens, 25 ... Fixed mirror, 101 ... Camera body, 102 ... Spool, 101a ... Patrone chamber, 101b ... Spool chamber, 106 ... Camera cover, 104, 105 ... Battery, 116- Reference numeral 118 ... Shooting lens, 115 ... Lens barrel, 111, 112 ... Converter lens, 110 ... Movable frame, 109 ... Movable mirror, 101d ... Short focus shooting aperture, 101e ... Long focus shooting aperture , 113 ... Shutter also used as diaphragm blades, 124 ... Movable frame, 124d ... Frame member (light-shielding member), 119 ... Light-shielding mask , 120, 122 ... sector gear, 121, 123 ... spring, 120c, 122c ... pin, 120d ... arm, 201 ... motor, 202 ... sun gear, 203 ... planet gear, 204 ... arm, 205 ... Fork drive gear, 206 ... Spool drive gear, 204a, 204b ... Finger, 208 ... Toggle spring, 210, 211 ... Stopper.

Claims (1)

[Claims] 1. An incident optical path for entering light, a first guide optical path for guiding the light incident from the incident optical path to a first image forming surface, and a light for entering the incident optical path. A second guide optical path shorter than the first guide optical path for guiding the second image forming surface, a selection unit for selecting the first guide optical path and the second guide optical path, and the incident optical path. A first lens system and a second lens system that moves in response to the selection means selecting the second guiding optical path to shorten the focal length of the first lens system. A focal length changing device for a camera.