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Image pickup apparatus

  • US 4,554,587 A
  • Filed: 02/18/1983
  • Issued: 11/19/1985
  • Est. Priority Date: 02/22/1982
  • Status: Expired due to Term
First Claim
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1. An apparatus for picking up incident image light, comprising:

  • (a) an image sensing element having an image pickup surface for receiving and sensing incident image light;

    (b) diaphragm means, responsive to an aperture control signal and disposed along an optical path of the image light incident on said image sensing element, for setting an aperture size from and including a first aperture size corresponding to a fully opened diaphragm state to and including a second aperture size corresponding to a predetermined lower limit diaphragm state which is no smaller than 2% of said fully opened diaphragm state, thereby controllably changing the amount of said image light incident on said image sensing element;

    (c) filter means, disposed along said optical path of said image light incident on said image sensing element and having an electrochromic layer of an electrochromic material, for changing transmissivity of said electrochromic layer in accordance with said aperture control signal selectively applied thereto, thereby changing the amount of said image light incident on said image sensing element; and

    (d) exposure controlling means, selectively outputting said aperture control signal to said diaphragm means and said filter means to perform an exposure control operation with respect to said image sensing element, for only controlling said diaphragm means to set aperture size thereby performing said exposure control operation when illuminance of actual incident image light is smaller than a predetermined reference illuminance, and for controlling said diaphragm means to set and hold aperture size at said second aperture size and for controlling said filter means so as to change said transmissivity and thereby perform said exposure control operation when illuminance of actual incident image light is not less than said predetermined reference illuminance.

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