JPS62937A - Electronic still camera - Google Patents

Abstract

PURPOSE:To prevent a camera shake during mirror conversion by using a plate type mirror as a reflecting mirror which guides light to a viewfinder and allowing it to rotate, swing, and slide on the same plane. CONSTITUTION:A discoid mirror 10 is made of a transparent material such as glass and provided with total reflecting surfaces 10a which have a reflection factor of 100% and transmission surfaces 10b which have a reflection factor of about 5% so that the surface of the disk is divided equally into four. The output shaft of a motor 11 is fixed in the center of the mirror disks 10 and installed at 45 deg. to an optical path, and photointerrupters 12 and 12 are provided at two positions of the outer peripheral part of the mirror disk 10 to detect the rotational position of the mirror disk 10. A photometric sensor 13 is provided on an optical path of light which is emitted from a photographic optical system, reflected by the disk 10, and mode incident on a viewfinder optical system and about 5% of reflected light is measured by the sensor 13. The disk 10 is rotationally symmetrical and formed slightly large, so when it rotates by 90 deg., it rotates on the same plane and the rotation is balanced, so even if there is a little remaining vibration at the stop of the disk, its influence upon a photographic image plane and a finder image can be ignored.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic still camera using a solid-state image pickup device, and more particularly to a finder of an electronic still camera and a mirror device for switching between a light beam and an imaging light beam.

[Prior Art] In a conventional single-lens reflex camera using 35 mm film, a total reflection quick return mirror 1 is used to control the viewfinder 3 and film 4, as shown in FIG.
The optical path is switched to That is, the screen captured by the photographic lens system 2 is normally guided toward the finder optical system 3 to aim as a bright finder image, and only when photographing, the quick return mirror 1 is raised so that the entire amount of light is projected onto the film 4 side. The shutter 5 performs exposure for the necessary time, and then returns to its original position to allow the entire amount of light to enter the finder optical system. It is possible to fix this mirror 1 and make it reflect 50%, for example, so that 50% of the light flux is incident on the finder optical system and the film, but the amount of light is insufficient for both the finder and the film, and the finder is dark. Conventionally, this method has rarely been used because it becomes difficult to obtain a clear image and also takes a long time to photograph.

Furthermore, as shown in FIG. 9, in conventional electronic still cameras, a solid-state image sensor 6 such as a CCD is used instead of film.
By simply using a , there is no need for a winding/rewinding device to move the film, but a magnetic disk 7 and a drive motor 8 to rotate it at high speed are required, making the electronic still camera itself bulky. It ends up. Although the image-receiving surface of the CCD, which is the solid-state image sensor 6, is about 1/4 smaller than that of 35+am film, the quick return mechanism quickly moves the mirror like the single-lens reflex camera shown in Figure 8 above. If you move the camera to
Even if the impact force is softened by using a tamper, etc., a loud noise is generated, which is inconvenient for quiet shooting. Furthermore, the mirror cannot follow high-speed photography such as 20 frames per minute, making quick photography impossible.

[Problems to be Solved by the Invention] As mentioned above, the quick return device of the conventional single-lens reflex camera has a great advantage in that the viewfinder field of view is the same as the photographing screen and a bright finder image can be observed. A large space is required for the mirror to flip up, and when the mirror stops, although it is softened by a damper, it makes a loud impact noise and generates vibrations, resulting in blurred photographs. Furthermore, it was impossible to shoot at high speeds such as 20 frames per minute.

Therefore, the present invention provides a small-sized mirror drive device that can be used as a finder device for an electronic still camera using a solid-state image sensor such as a CCp, which can also perform high-speed photography, and which produces less impact noise and vibration.

[Means and effects for solving the problem] In the present invention, the mirror that switches between the photographing optical path and the finder optical path is rotated, oscillated, or moved within the same plane. Since the reflective surface is larger than the required light flux, even if the mirror switching drive device is rough and the mirror stop position is slightly shifted or vibration remains, it will not affect photography or viewfinder observation. I don't give it either. In addition, since the mirror has good rotational balance, it has a structure that reduces the generation of noise such as collisions.

In addition, high-speed photography of 20 frames per minute, which was impossible with conventional single-lens reflex cameras, becomes possible, and the performance of electronic still cameras can be improved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIGS. 1A and 1B show a front view and a side view of the mirror. The disk-shaped mirror 10 is made of a transparent material such as glass, and has a total reflection surface 10a with a reflectance of 100% and a reflection surface 10a. The transmission surface 10b having a transmission rate of about 5% is divided into four parts and arranged. The output shaft of a motor 11 is directly fixed to the center of this mirror disk 10, and is installed at an angle of 45 degrees in the optical path. Furthermore, photointerrupters 12 and 12 are provided at two locations on the outer periphery of the mirror disk 10 to detect the rotational position of the mirror disk IO. on the other hand,
As shown in FIG. 1(B), a photometric sensor 13 is disposed on the optical path that is reflected from the photographing optical system by the mirror disk 10 and enters the finder optical system.

The mirror disk 10 is designed so that the photometry sensor 13 can measure about 5% of the reflected light even during photographing.

In addition, a photo interrupter 12.1 which is a position sensor
2 may be provided at positions A and B in FIG. 1(A).

In this example configured in this way, the mirror disk 10 is rotationally symmetrical and made slightly larger, so when it rotates 90 degrees, it rotates within the same plane, so the rotation is balanced, and when stopped Even if a small amount of vibration remains, the effect on the photographic screen and viewfinder image can be ignored, and the conventional problems can be solved.

Next, a second embodiment of the present invention will be described based on FIGS. 12(A) and 12(B). The mirror disk 20 is made of a transparent material such as glass, similar to that shown in FIG. 1, and is divided into two parts: a total reflection surface 20a and a transmission surface 20b. The center of this mirror disk 20 is supported by a bearing 26, and is arranged at an angle of 45 degrees to the optical path. Also,
The mirror disk 20 is rotated by the meshing engagement between a gear 20c provided on the outer periphery of the mirror disk 20 and a small gear 25 provided on the output shaft of the motor 24.

In this example as well, the rotational position of the mirror disk 20 is controlled by two photointerrupters 22. Further, since the reflective surface of the mirror disk 20 is larger than that of the first embodiment, and there is a margin for the reflective surface 20a, the positioning performed when the mirror is stopped can be made more roughly.

Furthermore, since drive control can be performed without disposing a motor or the like near the optical system, the overall configuration of the electronic camera becomes easier.

In the above two examples, the mirror discs are rotated within the same plane, but in the third embodiment shown in FIG. 3, the mirrors are oscillated within the same plane. That is, a total reflection mirror 30 is provided on a battledore-shaped support frame 31, and is arranged at an angle of 45 degrees in the optical path with the support shaft 35 as the center of rotation.

This mirror support frame 31 is provided with a gear 32 around a support shaft 35, which meshes with a gear 34 attached to the output shaft of a motor 33, and when the motor 33 rotates, the mirror 30
is designed to switch the optical path by swinging in and out of the optical path.

In this example, the above 1. Compared to the second embodiment, it requires less space and is more compact.

Next, a fourth embodiment of the present invention will be described based on FIG. Whereas in the third embodiment, the mirror is swung by a motor, in this example the mirror is swung by a solenoid. That is, the battledore-shaped mirror 40 is supported so as to swing about a support shaft 41 as a center of rotation, and is arranged on a machine frame (not shown) so as to form an angle of 45 degrees to the optical path. A balancer 4 is located on the opposite side of the mirror 40 across this support shaft 41.
2 are integrally attached. This balancer 42
A stopper arm 44 supported by a pivot 43 comes into contact with the stopper arm 44, and a stopper spring 45 whose one end is fixed to the machine frame is applied to urge the stopper arm 44 clockwise.

Further, a buffering oil damper 46 is disposed between the stopper arm 44 and the machine frame.

An operating rod 48 which is pin-coupled to the plunger of a solenoid 47 is connected to the arm portion of the mirror 40.
A return spring 49 is hung on the opposite side of 7 between it and the machine frame. Therefore, when the solenoid 37 is actuated, the mirror 40 swings clockwise and moves out of the optical path. When the power to the solenoid is cut off, the mirror 40 is returned to the optical path by the return spring 49, but at this time the balancer 42 comes into contact with the stopper arm and stops. This stopper arm 43 is provided with a damper 46 to soften the impact force.

In the case of this example, the response is better than that of the third embodiment, and the drive control of the mirror is easier.

Next, a fifth embodiment of the present invention will be described based on FIG. This example also applies to the third example above. Similar to the fourth embodiment, the mirror is oscillated. That is, the battledore-shaped mirror 50 has its center of rotation around a support shaft 51 provided on its arm, and is disposed at an angle of 45 degrees on a machine frame (not shown).

On the opposite side of the mirror 50 across the support shaft 51, an arm 52 extending in an arc shape from side to side is integrally provided, and each arm has a magnet at its tip and also serves as a balancer. Voice coils 53 are disposed to be inserted around the magnet portions at the tips of the arms 52 on both sides.

Therefore, when the coil 53 is energized, the mirror 50
swings clockwise around the support shaft 51 and is removed from the optical path. When the power is turned off, the repulsion of the magnet disappears and the device returns to its original state.

In this example as well, control is well-balanced and responsiveness can be improved.

Next, a sixth embodiment of the present invention will be described based on FIG. In this example, the mirrors are slid on the same surface. That is, the mirror 60 is held by a support frame 61, and two guide shafts are inserted through the support frame 61.
It is arranged at an angle of 45 degrees in the optical path. A coil 64 is supported on one support member 63 of the guide shaft 62, and an operating rod 65 extending from the mirror support frame 61 is supported within the coil 64.
is inserted. The tip of the operating rod 65 is made of a magnet.

Therefore, when the coil 64 is energized, the magnet of the operating rod 65 is drawn to the right, and the mirror 60 slides out of the optical path. Note that it is also possible to provide a rack on the operating rod, and to engage the pinion attached to the output shaft of the motor with the rack so that the rack slides. Furthermore, it is of course possible to configure the mirror 60 to slide not only in the six directions of left and right arrows, but also in the vertical direction of arrow B.

In this example, the mirror only moves in a straight line, so the area required overall is smaller than in other examples, and even if the mirror does not stop exactly, the reflective surface of the mirror 60 can be made larger with a little margin. This can be covered by setting e.

Next, a seventh embodiment of the present invention will be described based on FIG. The mirror disk 1 in this example is divided into four parts, as in the first embodiment shown in FIG. The difference from the first embodiment is that the counter disk 71 comes into contact with the mirror disk 1 to eliminate the influence on the camera body caused by sudden rotation or stopping of the mirror disk 1. That is, the counter disc 7
1 is supported by arm 72. This arm 72 is the support shaft 7
3, it is attached to the machine frame (not shown).

A compression spring 74 is hung between the arm 72 and the machine frame, and rotates clockwise about the support shaft 73 to bring the circumferential surface of the counter disk 71 into contact with the circumferential surface of the mirror disk 1. Let them come into contact with you. Rubber 75, which is an elastic friction member, is attached to the circumferential surface of the counter disk 71 and frictionally engages with the mirror disk 1. Therefore, when rotating the mirror disk 1 by rotating the motor 11 to move the reflective surface 1a in and out of the optical path,
It is possible to reduce the shock caused by the reaction on the camera body due to the sudden rotation stop of the mirror disc 1. Also, by rotating this counter disc 71 with the motor 76,
It is also possible to weaken the reaction.

[Effects of the Invention] In this invention, the reflecting mirror that guides the viewfinder is a plate-shaped mirror, and is configured to rotate, swing, or slide within the same plane, so that the impact received by the camera body during mirror conversion is reduced. There is no noise, and therefore no camera shake occurs. Furthermore, since the mirror only moves within the same plane, even if vibrations remain when the mirror is stopped, it can be used without affecting both the photographed image and the viewfinder image. Furthermore, since it is easy to balance the rotation, a simple control drive system is required. In addition, since the mirror can be moved at high speed, high-speed photography of 20 frames per minute, which is unimaginable with conventional single-lens reflex cameras, is also possible.

[Brief explanation of drawings]

FIGS. 1(A) and (B) are front and side views of a mirror disk showing one embodiment of the present invention, and FIGS. 2(A) and (B) show a second embodiment of the present invention. FIG. 3 is a front view of a mirror drive device showing a third embodiment of the present invention, and FIG. 4 is a front view of a mirror drive device showing a fourth embodiment of the present invention. 5 is a front view of a mirror drive device showing a fifth embodiment of the present invention; FIG. 6 is a front view of a mirror drive device showing a sixth embodiment of the present invention; FIG. 7 is a front view of a mirror drive device showing a sixth embodiment of the present invention; FIG. 8 is a sectional view of the optical system of a conventional single-lens reflex camera; FIG. 9 is a front view of a mirror driving device showing a seventh embodiment of the present invention; FIG. 9 is a cross-sectional view of the optical system of a conventional electronic camera and a recording device. FIG. 10.20.30.40.50.80・・・・・・・・・
・Mirror Bon 2 Zu Ka 3 Z Ka 5 Senpen Cuff Scheme 80

Claims (1)

[Claims] An electronic still camera comprising an optical system that forms an image of a subject on a photoelectric conversion surface of an image sensor, and a plate-shaped mirror that is inserted into the optical system and guides light incident on the image sensor to a finder. . An electronic still camera, wherein the mirror is configured to be displaced in a direction along its own reflective surface at a predetermined timing.