Active matrix display device having additional capacitors connected to switching elements and additional capacitor common line

• US 5,159,477 A
• Filed: 11/20/1990
• Issued: 10/27/1992
• Est. Priority Date: 11/22/1989
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shimada, Takayuki, Takafuji, Yutaka, Matsushima, Yasuhiro
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): TRAN, MINH LOAN
• Application Number:
  US07/615,949
• Time in Patent Office: 707 Days
• Field of Search: 357/23.7, 357/4, 357/51, 340/784, 350/333, 350/332, 350/334, 350/336, 359/54, 359/59, 359/87, 359/88
• US Class Current: 349/39
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode

Abstract

An active matrix display device having low resistance additional capacitor common lines and additional capacitors in which each of the additional capacitors has a first electrode connected to a switching element and a second electrode connected to the additional capacitor common line, and the additional capacitor common line is made of the same material as the signal lines, so that the possibility of signal delay on the additional capacitor common lines is reduced.

Claims

1. An active matrix display device comprising a pair of insulating substrates, pixel electrodes arranged in a matrix pattern on an inner side of one of the pair of substrates, switching elements connected to the respective pixel electrodes, signal lines connected to the respective switching elements for supplying a video signal thereto, at least one additional capacitor for retaining charge in each pixel electrode, and additional capacitor common lines connected to the additional capacitor,

said each additional capacitor having a first electrode connected to a drain electrode of said switching element and a second electrode connected to the additional capacitor common line, thereby securing connection between said switching element and the additional capacitor, said each additional capacitor common line being made of the same material as said signal lines.

2. An active matrix display device according to claim 1, wherein a drive circuit for supplying a video signal to said signal line is formed on said inner side of said substrate.

3. An active matrix display device according to claim 2, wherein a video signal is held by the additional capacitor connected to said corresponding signal lines.

4. An active matrix display device comprising a pair of insulating substrates, pixel electrodes arranged in a matrix pattern on an inner side of one of the pair of substrates, switching elements connected to the respective pixel electrodes, signal lines connected to the respective switching elements for supplying a video signal thereto, additional capacitors for retaining charge in each pixel electrode, and additional capacitor common lines connected through contact holes to one electrode of the additional capacitor,

said each additional capacitor having a first electrode connected to a drain electrode of said each switching element and a second electrode connected to said each additional capacitor common line so as to secure connection between said each switching element and each additional capacitor, said each additional capacitor common line being provided below each pixel electrode in a parallel relation to said signal line.

5. An active matrix display device according to claim 4, wherein a drive circuit for supplying a video signal to said signal line is formed on said inner side of said substrate.

6. An active matrix display device according to claim 5, wherein a video signal is held by the additional capacitors connected to said corresponding signal lines.

7. An active matrix display device comprising a pair of substrates, pixel electrodes arranged in a matrix pattern on an inner side of one of the pair of substrates, the inner side of the substrate being covered with an insulating layer having a first, second, and third contact holes with respect to each pixel electrode, switching elements connected to the respective pixel electrodes, signal lines connected to the respective switching elements for supplying a video signal thereto, an additional capacitor for retaining charge in the pixel electrode, the additional capacitor being located below the corresponding pixel electrode, a semiconductor layer covered with a gate insulating film and connected to the pixel electrodes and the signal line through the first and second contact holes, and an additional capacitor common line connected to the additional capacitor through the third contact hole;

said each additional capacitor having a first electrode connected to a drain electrode of said switching element and a second electrode connected to the additional capacitor common line, thereby securing connection between said switching element and the additional capacitor, said each additional capacitor common line being made of the same material having a relatively low resistivity as said signal lines so as to avoid a delay of signal transmission.