Display device driver IC

• US 6,489,940 B1
• Filed: 07/28/1999
• Issued: 12/03/2002
• Est. Priority Date: 07/31/1998
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Aoki, Tadashi
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Osorio, Ricardo
• Application Number:
  US09/362,054
• Time in Patent Office: 1,224 Days
• Field of Search: 345/87, 345/90, 345/91, 345/93, 345/98, 345/94, 345/204, 345/100
• US Class Current: 345/93
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/3681 suitable for passive matrices only
• CPC Class Codes: G09G 3/3692 suitable for passive matrices only

Abstract

A driver IC (integrated circuit) for a display device allowing simple designing and production and yet capable of obviating display quality difference is provided. The driver IC includes a plurality of drive signal output terminals arrange to have variable drive capacities which vary depending on loads of respective signal electrodes of the display device to which the output terminals are connected so as to supply the respective signal electrodes of the display device with drive signal waveforms having identical time constant. The driver IC preferably includes a number of juxtaposed transistors corresponding to but larger in number than the drive signal output terminals, wherein the respective drive signal output terminals are connected to prescribed numbers of transistors so as to have different drive capacities depending on loads of the signal electrodes of the display device to which the output terminals are connected.

Claims

1. A driver IC for supplying drive signals to a plurality of signal electrodes of a display device for driving the display device, wherein said driver IC comprises a plurality of drive signal output terminals arranged to have variable drive capacities which vary depending on loads of respective signal electrodes of the display device to which the output terminals are connected so as to supply the respective signal electrodes of the display device with drive signal waveforms having identical time constant, and comprising a number of juxtaposed transistors corresponding to but larger in number than the drive signal output terminals, wherein the respective drive signal output terminals are connected to prescribed numbers of transistors so as to have different drive capacities depending on loads of the signal electrodes of the display device to which the output terminals are connected.

2. The driver IC according to claim 1, wherein the transistors are each formed of a plurality of layers, and the prescribed numbers of transistors are connected to the respective drive signal output terminals by providing a connection wire for connecting at least one layer of the transistors.

3. The driver IC according to claim 2, wherein the connection wire is provided by a pattern change for formation of a wire associated with said at least one layer.

4. The driver IC according to claim 1, wherein a portion of the drive signal output terminals are each connected to two or more transistors to be provided with an increased drive capacity.

5. The driver IC according to claim 1, wherein all the drive signal output terminals are each connected to two or more transistors to be provided with an increased drive capacity.

6. The driver IC according to claim 1, wherein the number of the drive signal output terminals is effectively decreased.

7. The driver IC according to claim 1, wherein the load of each signal electrode comprises a resistance of the signal electrode and capacitances of liquid crystal pixels formed along the signal electrode.