Electronic image pickup apparatus

Details Electronic image pickup apparatus Electronic image pickup apparatus

1998-09-08

2003-12-16

Christensen, Andrew (Department: 2615)

Television

Camera, system and detail

C348S272000, C348S340000, C348S362000, C396S443000, C396S448000

Reexamination Certificate

active

06665005

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an electronic image pickup apparatus, such as an electronic camera, comprising a color image pickup element for generating a color image signal, a zooming lens for changing the magnification of an image of the color image pickup element on a photoelectric conversion surface, and a zooming lens frame for supporting the zooming lens.
In general, a color image pickup element in an electronic image pickup apparatus, such as an electronic camera, has a color filter provided near the surface of the element. When the color filter is exposed to external light for a long time, the color tone is deteriorated, that is, so-called discoloration occurs. Therefore, the color of the photographed image is imbalanced.
A silver salt film camera does not suffer from the aforementioned problem of discoloration, since it employs a system in which the shutter is closed when the power is OFF (normally close system). However, an electronic image pickup camera, e.g., a digital camera, perform photometry, focus detection and photographing monitor on the basis of light incident on an image pickup element. Therefore, the mechanical shutter is open for a long time, and closed only at the photographing moment. The electronic image pickup apparatus employs a system in which the shutter is open when the shutter is not driven (normally open system), so that the power can be saved.
Thus, in the electronic image pickup apparatus, since the time in which the shutter is open is considerably longer as compared to the case of a silver salt film camera, the problem of discoloration of the color filter arises.
To solve the problem, various means have been proposed to mechanically shield the image pickup element from external light in the non-photographing time. For example, Jpn. Pat. Appln. KOKOKU Publication No. 62-43636 discloses a mechanism for inserting a light shield plate for use in white balance adjustment into an image pickup lens in cooperation with a power operation member.
Recently, however, automatic white balance adjustment has become a main current. Therefore, to use a light shielding plate for white balance adjustment also as a shutter plate for preventing discoloration of the color filter as disclosed in the above publication, the light shielding plate for the white balance adjustment, which is actually unnecessary, must be incorporated in the apparatus. This is considerably disadvantageous in space and cost. Further, since the mechanism disclosed in the above publication is a system for mechanically moving the light shielding plate in cooperation with the power operation member, a number of restrictions in mechanism and arrangement are imposed. For this reason, it is difficult to apply such a plate to a compact device, for example, a digital camera.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide an electronic image pickup apparatus having means for surely preventing, with a simple structure, discoloration of the color filter attached to the image pickup element, while the shutter plate for exposure control can be shut without operating the shutter driving source, when a photographing operation is completed.
To achieve the above object, the electronic image pickup apparatus of the present invention has the following constitution. The features of the present invention other than the following will be clarified in the description of the embodiments.
An electronic image pickup apparatus of the present invention comprises a shutter having: a shielding member which can be inserted into or removed from an optical path of an optical system for forming an image of an object on a light receiving surface of an image pickup element; an inserting/removing mechanism for inserting or removing the shielding member into or from the optical path; a driver for driving the inserting/removing mechanism; and a manipulator for operating the inserting/removing mechanism by a driving system other than the driver.


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