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Over-door interphone system provided with a night-vision monitoring device

  • US 4,843,461 A
  • Filed: 02/06/1987
  • Issued: 06/27/1989
  • Est. Priority Date: 06/25/1985
  • Status: Expired due to Term
First Claim
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1. An over-door interphone system provided with a night-vision monitoring device comprising:

  • a master station unit located inside of a house;

    a remote station unit located outside of an entrance door of the house, said remote station unit being connected to the master station unit for telecommunication between a vistor and a dweller, said remote station unit includinga housing,a television camera mounted within the housing to comprise an optical unit including a solid state camera sensitive to infrared light and optical lens means disposed in front thereof,control circuit means mounted adjacent to the optical unit for controlling the optical unit,call switch means within the housing for calling the master station unit, andtelecommunication means within the housing for telephonic intercommunication between the master and remote station units;

    saidmaster station unit including a video display for monitoring an image of the visitor picked up by said television camera;

    an infrared light emitting illumination means located adjacent the remote station unit; and

    an illumination control means for providing a driving output to said infrared light emitting illumination means to actuate the same for producing the infrared light intermittently in synchronism with the operation of said television camera after determining that illuminance of an object image is lower than predetermined level.

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