Active matrix type display apparatus

• US 5,598,180 A
• Filed: 03/04/1993
• Issued: 01/28/1997
• Est. Priority Date: 03/05/1992
• Status: Expired due to Term

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Suzuki, Kouji, Suzuki, Kouhei
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): WU, XIAO MIN
• Application Number:
  US08/029,323
• Time in Patent Office: 1,426 Days
• Field of Search: 340/784, 340/811, 340/805, 345/211, 345/212, 345/208, 345/209, 345/210, 345/98, 345/213, 345/100, 345/99, 345/94, 345/95, 345/96, 345/87, 359/54, 359/55
• US Class Current: 345/100
• CPC Class Codes: G09G 2310/0289 Details of voltage level shifters arranged for use in a driving circuit
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• 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 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

An active-matrix type liquid-crystal display comprising a matrix display panel including a glass substrate, pixel electrodes formed on the substrate, signal lines formed on the substrate, gate lines formed on the substrate, and switching elements formed on the substrate, signal-line drive ICs for applying signal voltages to the signal lines, and gate-line drive ICs for driving the switching elements. The display further comprises power-supply potential control circuits for changing the first and second power-supply potentials (VDD, VSS) of the signal-line drive ICs, each by a predetermined value, in accordance with the signal voltages to be applied to the pixel electrodes.

Claims

1. An active-matrix type display apparatus comprising:

a matrix display panel including a substrate having a major surface, a plurality of pixel electrodes arranged on said substrate in rows and columns, a plurality of signal lines formed on the major surface of said substrate and extending among the columns of said pixel electrodes, a plurality of gate lines formed on the major surface of said substrate, crossing said signal lines and extending among the rows of said pixel electrodes, a plurality of switching elements each connected between a corresponding one of said pixel electrodes and a corresponding one of said signal lines and controlled by a corresponding one of said gate lines, a common electrode opposite to said pixel electrodes and held at a constant potential, and liquid crystal filled between said substrate and said common electrode;

gate-line drive means for applying a gate-drive voltage to each of said gate lines;

power-supply means for generating a first power-supply potential and a second power-supply potential lower than the first power-supply potential, each of the first and second power-supply potentials having respective high and low levels, with the first and second power-supply potentials synchronously varying between their respective high and low levels at predetermined intervals while maintaining a predetermined potential difference therebetween; and

signal-line drive means applied by the first power-supply potential and the second power-supply potential to be operated, for applying a signal voltage which is inverted in polarity at the predetermined intervals to each of said signal lines.

2. The display apparatus according to claim 1, wherein said power-supply means generates the first and second power-supply potentials varying between the respective high and low levels for each field or each frame.

3. The display apparatus according to claim 1, wherein said power-supply means generates the first and second power-supply potentials with the low level of the first power-supply potential being set at the high level of the second power-supply potential.

4. The display apparatus according to claim 3, wherein said common electrode is kept at the constant potential equal to the low level of the first power-supply potential and the high level of the second power-supply potential.

5. The display apparatus according to claim 1, wherein said power-supply means includes switching means for switching the first and second power-supply potentials between the high and low levels for each field or each frame.

6. An active-matrix type display apparatus comprising:

a matrix display panel including a substrate having a major surface, a plurality of pixel electrodes arranged on said substrate in rows and columns, a plurality of signal lines having odd-numbered signal lines and even-numbered signal lines which are formed on the major surface of said substrate and extend among the columns of said pixel electrodes, a plurality of gate lines formed on the major surface of said substrate, crossing said signal lines and extending among the rows of said pixel electrodes, a plurality of switching elements each connected between a corresponding one of said pixel electrodes and a corresponding one of said signal lines and controlled by a corresponding one of said gate lines, a common electrode opposite to said pixel electrodes and held at a constant potential, and liquid crystal filled between said substrate and said common electrode;

a gate-line drive circuit for applying a gate-drive voltage to each of said gate lines;

a first power-supply circuit for generating a first power-supply potential and a second power-supply potential lower than the first power-supply potential, each of the first and second power-supply potentials having respective high and low levels, with the first and second power-supply potentials synchronously varying between their respective first and second levels at predetermined intervals while keeping predetermined levels and maintaining a predetermined potential difference therebetween;

a second power-supply circuit for generating a third power-supply potential and a fourth power-supply potential lower than the third power-supply potential, each of the third and fourth power-supply potentials having respective high and low levels, with the third and fourth power-supply potentials synchronously varying between their respective high and low levels at predetermined intervals while keeping predetermined levels and maintaining a predetermined potential difference therebetween, the third and fourth power-supply potentials being inverted in polarity to the first and second power-supply potentials, respectively;

a first signal-line drive circuit connected to said first power-supply circuit and driven by the first power-supply potential and the second power-supply potential, for applying a signal voltage which is inverted in polarity at the predetermined intervals to each of the odd-numbered signal lines; and

a second signal-line drive circuit connected to said first power-supply circuit and driven by the third and fourth power-supply potentials, for applying a signal voltage which is inverted in polarity at the predetermined intervals to even-numbered signal lines.

7. The display apparatus according to claim 6, wherein said first power-supply circuit generates the first and second power-supply potentials varying between the respective high and low levels for each field or each frame and said second power-supply circuit generates the third and fourth power-supply potentials varying between the respective high and low levels for each field or each frame.

8. The display apparatus according to claim 6, wherein said first power-supply circuit generates the first and second power-supply potentials with the low level of the first power-supply potential being set at the high level of the second power-supply potential and said second power-supply circuit generates the third and fourth power-supply potentials with the low level of the third power-supply potential being set at the high level of the fourth power-supply potential.

9. The display apparatus according to claim 8, wherein said common electrode is kept at the constant potential equal to the low level of the first power-supply potential and the high level of the second power-supply potential.

10. The display apparatus according to claim 6, wherein each of said first and second power-supply circuits includes a switch circuit for switching the first and second power-supply potentials between the high and low levels for each field or each frame.

11. An active-matrix type display apparatus comprising:

a matrix display panel including a substrate having a major surface, a plurality of pixel electrodes arranged on said substrate in rows and columns, a plurality of signal lines formed on the major surface of said substrate and extending among the columns of said pixel electrodes, a plurality of gate lines formed on the major surface of said substrate, crossing said signal lines and extending among the rows of said pixel electrodes, a plurality of switching elements each connected between a corresponding one of said pixel electrodes and a corresponding one of said signal lines and controlled by a corresponding one of said gate lines, a common electrode opposite to said pixel electrodes, and liquid crystal filled between said substrate and said common electrode;

a plurality of gate-line drive circuits each applying a gate-drive voltage to each of respective ones of said gate lines;

a plurality of power-supply circuits each generating a first power-supply potential and a second power-supply potential lower than the first power-supply potential, each of the first and second power-supply potentials having respective high and low levels, with the first and second power-supply potentials synchronously varying between their respective high and low levels at predetermined intervals while maintaining a predetermined potential difference therebetween; and

a plurality of signal-line drive ICs each supplied and operated by the first power-supply potential and the second power-supply potential, for applying a signal voltage which is inverted in polarity at the predetermined intervals to each of said signal lines.

12. The display apparatus according to claim 11, wherein said power-supply circuits each generate the first and second power-supply potentials varying between the respective high and low levels for each field or each frame.

13. The display apparatus according to claim 11, wherein said power-supply circuits each generate the first and second power-supply potentials with the low level of the first power-supply potential being set at the high level of the second power-supply potential.

14. The display apparatus according to claim 13, wherein said common electrode is kept at the constant potential equal to the low level of the first power-supply potential and the high level of the second power-supply potential.

15. The display apparatus according to claim 11, wherein said power-supply circuits each include analog switches for switching the first and second power-supply potentials between the high and low levels for each field or each frame.