Method for driving liquid crystal display device

• US 6,031,514 A
• Filed: 04/28/1997
• Issued: 02/29/2000
• Est. Priority Date: 04/28/1993
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hashimoto, Seiji, Ishii, Takayuki, Sugawa, Shigetoshi, Shigeta, Kazuyuki, Sono, Koichi, Yoshida, Daisuke, Kondo, Shigeki
• Primary Examiner(s): Hjerpe, Richard A.
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Application Number:
  US08/841,823
• Time in Patent Office: 1,037 Days
• Field of Search: 345/87, 345/92, 345/93, 345/94, 345/95, 345/96, 345/97, 345/98, 345/99, 345/100
• US Class Current: 345/94
• CPC Class Codes: G09G 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3677 suitable for active matrices only

Abstract

For enabling a liquid display drive with a low voltage and a high speed, each pixel is provided with a liquid crystal cell 5, a switching transistor 7 and an additional capacitance 9, and the additional capacitances are electrically commonly connected for a block of plural pixels. After the image signal is supplied to the pixels corresponding to the block, the potential of desired one of the common electrode lines 52, 52'"'"', to which the additional capacitances 9 corresponding to the block are connected, is varied and retained at thus varied value.

Claims

1. A driving method for a liquid crystal display device having a plurality of pixel electrodes, each corresponding to one of a plurality of pixels, a common electrode arranged opposite the pixel electrodes and disposed commonly to all the pixels, and liquid crystal sandwiched between each pixel electrode and the common electrode, each pixel being provided with a switching transistor for receiving a signal which is inverted at a desired interval, and an additional capacitance, having first and second electrodes for retaining the signal voltage, wherein for each of arbitrary blocks of pixels, the first electrode of each additional capacitance and the common electrode are commonly but mutually separately connected electrically, while the second electrode of each additional capacitance and the pixel electrodes are respectively connected to the switching transistors, said method comprising the steps of:

supplying the signal to the second electrodes of the additional capacitances and the common electrode through the switching transistors while a desired potential is supplied to the second electrodes of the additional capacitances; and

supplying a potential different from the desired potential to the second electrodes of the additional capacitances,

wherein any signal amplitude inverted at the desired interval overlaps with a voltage of the common electrode.