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Image display and its control method

  • US 7,876,294 B2
  • Filed: 03/05/2003
  • Issued: 01/25/2011
  • Est. Priority Date: 03/05/2002
  • Status: Active Grant
First Claim
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1. An image display apparatus comprising:

  • a pixel having a drive transistor and a pixel display element which are electrically connected in series between a first power line and a second power line, a holding capacitor electrically connected to a gate electrode of said drive transistor, and a selection transistor electrically connected between a signal line and the gate electrode of said drive transistor; and

    a controller for turning on said selection transistor thereby to write gradation pixel data in said holding capacitor from said signal line, discharging charges of the gradation pixel data written in said holding capacitor through said drive transistor for a predetermined time less than a frame time, and thereafter floating the gate electrode of said drive transistor thereby to hold the charges of the gradation pixel data stored in said holding capacitor;

    a display panel having a plurality of signal lines to which corresponding gradation pixel data are applied and a plurality of scanning lines to which scanning signals are applied, said pixel at positioned each of points of intersection between said signal lines and said scanning lines;

    a signal line driver for applying said gradation pixel data to said signal lines based on a pixel input signal; and

    a scanning line driver for applying said scanning signals to said scanning lines;

    wherein said selection transistor has a first drain electrode, a first source electrode, and a first gate electrode, said drive transistor has a second drain electrode, a second source electrode, and a second gate electrode, said holding capacitor holds a voltage between said second gate electrode and said second source electrode, and said pixel display element has a first electrode and a second electrode;

    wherein said first drain electrode/said first source electrode is connected to said signal line, said first source electrode/said first drain electrode is connected to said second gate electrode said first ate electrode is connected to said scanning line, and said selection transistor performs on/off control of a conduction state between said signal line and said second gate electrode based on said scanning signal;

    wherein said first power line is connected to said second drain electrode, said second source electrode is connected to said first electrode, and said drive transistor passes an output current controlled based on a voltage held by said holding capacitor from said second source electrode to said first electrode; and

    wherein said second power line is connected to said second electrode and said pixel display element displays a pixel at a gradation based on said output current of said drive transistor; and

    a plurality of resetting signal lines to which resetting signals are applied; and

    a resetting signal line driver for applying said resetting signals to said resetting signal lines;

    wherein said pixel has a resetting transistor having a third drain electrode, a third source electrode, and a third gate electrode, and a parasitic capacitor is formed between said first electrode and said second electrode;

    wherein said third drain electrode/said third source electrode is connected to said second source electrode, said third source electrode/said third drain electrode is connected to said second power line, said third gate electrode is connected to said resetting signal line, and said resetting transistor performs on/off control of a conduction state between said second source electrode and said second power line based on said resetting signal; and

    wherein said control means turns on said resetting transistor thereby to discharge said holding capacitor and said parasitic capacitor, and thereafter turns on said selection transistor.

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