JPH11190867A - Light control device and camera - Google Patents

Abstract

(57) [Problem] In a camera capable of performing both moving image shooting and still image shooting, it is necessary to provide separate light amount adjusting devices for moving images and still images. SOLUTION: In a light quantity adjusting device for adjusting the size of an aperture opening by moving a plurality of aperture blades 1 and 2 relatively, the size of the aperture opening can be continuously adjusted for each aperture blade. Form a fully-closed diaphragm when the first relative positional relationship is established and form a fully-closed diaphragm when the second relative positional relationship is established.
b and fixed diaphragm portions 1-a and 1-b that form a small diaphragm when the diaphragm blades have a third relative positional relationship.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light amount adjusting device used for a video camera, a digital still camera or the like.

[0002]

2. Description of the Related Art A video camera such as a video camera includes:
A moving image light amount adjusting device that continuously changes the aperture from an open state to a fully closed state is used. On the other hand, a still image capturing camera such as a digital still camera switches between two positions between an open state and a small aperture state (for example, F8),
Further, a still image light amount adjusting device capable of performing a shutter operation may be used.

[0003]

However, since the functions required for light quantity adjustment are different between a moving image and a still image, a camera that can perform both a moving image and a still image cannot be used for a moving image and a still image. It was necessary to provide separate light amount adjusting devices.

Accordingly, an object of the present invention is to provide a light amount adjusting device that can be used for both moving images and still images.

[0005]

In order to achieve the above object, according to the present invention, in a light quantity adjusting device for adjusting the size of an aperture opening by relatively moving a plurality of aperture blades, a continuous light is applied to each aperture blade. A continuously variable diaphragm unit that enables adjustment of the size of the diaphragm opening, forms an open diaphragm when the diaphragm blades have a first relative positional relationship, and forms a fully closed diaphragm when the diaphragm blades have a second relative positional relationship. And a fixed aperture section that forms a small aperture when these aperture blades have a third relative positional relationship.

[0006] When the light amount adjusting device configured as described above is attached to a camera capable of shooting moving images and still images,
A plurality of aperture blades are continuously driven between a first relative positional relationship and a second relative positional relationship during moving image shooting, and the plurality of aperture blades are switched between a first and a third relative positional relationship during still image shooting. For example, only one light amount adjusting device is required.

In photographing a still image, a plurality of aperture blades may be switched from the first or third relative positional relationship to the second relative positional relationship to perform a shutter operation.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a light amount adjusting device according to a first embodiment of the present invention. In this figure, 1 is a first aperture blade, and 2 is a second aperture blade. These aperture blades 1 and 2 have elongated holes 1-c and 2-c respectively fitted with shaft portions 6a and 6b formed at the end of a drive arm 6 that swings about a swing axis O. Have been. Guide grooves 1-d and 2-d into which guide pins 4 and 5 formed on a base plate (not shown) are fitted are formed on both the aperture blades 1 and 2, respectively. Therefore, when the drive arm 6 is oscillated about the oscillating axis O by an actuator such as a motor (not shown), the aperture blades 1 and 2 are vertically guided while being guided by the guide pins 4 and 5. Moving.

The two diaphragm blades 1 and 2 respectively have continuously variable diaphragm portions 1-b and 2-b which enable continuous adjustment of the diaphragm aperture between the open state and the fully closed state, and a small diaphragm ( For example, F
8) are formed with fixed throttle portions 1-a and 2-a. Reference numeral 3 denotes a fixed open opening formed in the base plate.

Next, the operation of the light quantity adjusting device thus configured will be described. First, as shown in FIG. 1A, when the drive arm 6 swings to the position of the angle A, the diaphragm blades 1 and 2 form an open diaphragm by the continuously variable diaphragm portions 1-b and 2-b. Position relationship (the first
(Relative positional relationship).

Further, as shown in FIG. 1B, when the drive arm 6 swings to the position of the angle B, the two diaphragm blades 1 and 2 move.
Is a positional relationship (a second relative positional relationship referred to in the claims) in which a fully open aperture is formed by the continuously variable aperture portions 1-b and 2-b.

As shown in FIG. 1C, when the drive arm 6 swings to the position of the angle C, the two diaphragm blades 1 and 2 move.
Is a positional relationship in which the fixed aperture portions 1-a and 2-a overlap to form a small aperture (third relative positional relationship in the claims).
become.

Here, when the drive arm 6 is continuously driven between the angle A and the angle B, the size of the aperture opening is changed by the continuously variable aperture portions 1-b and 2-b of both the aperture blades 1 and 2. It can be changed continuously.

When the drive arm 6 is driven in a two-position switching manner between the angle A and the angle C, the fully-opened aperture formed by the continuously variable aperture portions 1-b and 2-b of the aperture blades 1 and 2 is fixed. It is possible to perform stepwise switching with the small aperture formed by the aperture portions 1-a and 2-a.

For this reason, when this light amount adjusting device is attached to a camera capable of both moving image shooting and still image shooting, the driving arm 6 is continuously driven between the angle A and the angle B in the moving image shooting mode. Control (aperture mode for moving images), and set the drive arm 6 to the angle A
By performing control (still image aperture mode) for switching between two positions between the angle C and the angle C, it is possible to appropriately adjust the amount of incident light to the image sensor or the like according to the shooting mode.

Further, the drive arm 6 is set at the angle A or the angle C.
If the two-position switching control (still image shutter mode) is performed so as to drive the shutter to the angle B, the operation of switching from the fully-opened or small-aperture state to the fully-closed state at a stretch, that is, the shutter operation can be performed. Can be used as a shutter when shooting.

Next, the operation of the camera for capturing moving images and still images provided with the light amount adjusting device of the present embodiment will be described with reference to the flowchart of FIG. This flowchart explains the operation of a camera using a CCD of the all-pixel readout system. That is, the operations in the moving image aperture mode and the still image aperture mode (two-position switching) are described.

First, information as to whether the future shooting is moving image shooting or still image shooting is fetched. Next, a determination is made as to whether a moving image or a still image exists. Here, in the case of the moving image aperture mode, the moving image is photographed while the aperture continuously adjusts the light amount based on the luminance information of the CCD.

On the other hand, in the case of the aperture mode for a still image, when the shutter button is pressed halfway, the CCD accumulation time and aperture value are determined based on the luminance information of the CCD, and the aperture is automatically adjusted. Further, when the full-pressing of the shutter button is detected by, the CCD pixel information is read out after the predetermined CCD accumulation time passes by, and the still image shooting is ended by.

Next, the operation of a camera using a CCD of the sequential reading system will be described with reference to the flowchart of FIG. That is, the moving image aperture mode and the still image shutter aperture mode (shutter operation) will be described.

First, information on whether the shooting to be performed is moving image shooting or still image shooting is fetched. Next, a determination is made as to whether a moving image or a still image exists. Here, in the case of the moving image aperture mode, the moving image is photographed while the aperture continuously adjusts the light amount based on the luminance information of the CCD.

On the other hand, in the case of the shutter aperture mode for a still image, when the shutter button is half-pressed, the CCD accumulation time and the aperture value are determined based on the luminance information of the CCD, and the aperture is automatically adjusted. Further, when the full press of the shutter button is detected by, the aperture is closed and the CCD pixel information is read out after the diameter of the predetermined CCD accumulation time has passed by, and the still image shooting is terminated by.

[0023]

As described above, according to the present invention,
With a simple configuration, it is possible to realize a light amount adjusting device capable of performing both a light amount adjusting operation suitable for moving image shooting and a light amount adjusting operation suitable for still image shooting. In particular, in the light amount adjusting device of the present invention, the configuration of the aperture blades is devised to have both the moving image shooting aperture function and the still image shooting aperture function, so that the number of components (the number of parts) does not increase. It is economical. Therefore, a camera that performs moving image shooting and still image shooting can be configured compactly and inexpensively, and the amount of light suitable for moving image shooting and still image shooting can be adjusted by performing simple control.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an operation of a light quantity adjusting device according to a first embodiment of the present invention.

FIG. 2 is an operation flowchart of a camera provided with the light amount adjusting device (when the CCD uses an all-pixel reading method).

FIG. 3 is an operation flowchart of a camera provided with the light amount adjusting device (when the CCD uses a sequential reading method).

[Explanation of symbols]

 1, 2 diaphragm blades 1-a, 2-a fixed diaphragm unit 1-b, 2-b continuously variable diaphragm unit 6 drive arm

Claims (3)

[Claims] 1. A light amount adjusting device for adjusting the size of an aperture opening by relatively moving a plurality of aperture blades, wherein the size of the aperture opening can be continuously adjusted on each of the aperture blades, and A continuously variable diaphragm unit that forms an open diaphragm when the first relative positional relationship is established and forms a fully closed diaphragm when the second relative positional relationship is established, and the diaphragm blades are in a third relative positional relationship. A light amount adjusting device, characterized in that a fixed stop portion that sometimes forms a small stop is formed. 2. A light amount adjusting device according to claim 1, further comprising:
In a camera capable of shooting moving images and still images, the plurality of aperture blades are continuously driven between the first relative positional relationship and the second relative positional relationship during moving image shooting, and the plurality of aperture blades are driven during still image shooting. A camera, wherein an aperture blade is driven to switch between the first and third relative positional relationships. 3. A still image capturing operation, wherein the plurality of aperture blades are driven to switch from the first or third relative positional relationship to the second relative positional relationship to perform a shutter operation. 3. The camera according to 2.