Liquid crystal display unit having large image area and high resolution

• US 5,159,476 A
• Filed: 12/28/1989
• Issued: 10/27/1992
• Est. Priority Date: 12/28/1988
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hayashi, Yuji
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): CLARK, SHEILA V
• Application Number:
  US07/458,397
• Time in Patent Office: 1,034 Days
• Field of Search: 350/334, 350/333, 350/332, 350/335, 340/784, 359/54, 359/59, 359/53
• US Class Current: 349/39
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode

Abstract

A liquid crystal display unit is provided wherein address lines for two mutually adjacent odd and even rows of pixels arrayed in a matrix are in common, and two vertical pixels on each column can be displayed simultaneously to enable display of an image corresponding to one frame. Capacitor forming electrode wires are supplied with a fixed potential are disposed between omitted rows of address lines eliminated due to the common use thereof, whereby the storage capacitors are of a sufficiently high value, even with a high resolution display, to enhance the image quality of the liquid crystal display unit. Since a fixed potential is applied to the capacitor forming electrode wire which forms the storage capacitor, the capacitor does not apply a load to the address line and thereby consistently insures a fast operation. As a result, improvements can be achieved relating to large image area and high resolution. Furthermore, each pixel includes a switching transistor which is composed of a thin film transistor having a high carrier mobility and is formed under a single line so that even when the on-resistance of the transistor is lowered, the aperture ratio of the pixel is still enhanced to obtain a high resolution.

Claims

1. A liquid crystal display device, comprising:

a plurality of pixels arrayed in a matrix, each pixel having;

a transparent pixel electrode, and

a switching device for driving each of the pixels, said switching device being formed under a signal line;

a plurality of signal lines, each signal line being comprised of the signal line for supplying a signal voltage to each of an electrode of the switching device, and extending over a portion of the transparent pixel electrode; and

a plurality of address lines connected to rows of said pixels in said matrix.

2. A liquid crystal display unit as claimed in claim 1, wherein said switching device of each pixel is a thin film transistor.

3. A liquid crystal display unit as claimed in claim 2, wherein said thin film transistor of each pixel has a drain region, said drain region of each transistor being electrically connected to a portion of a corresponding one of said pixel electrodes under a respective one of said signal lines.

4. A liquid crystal display unit as claimed in claim 2, wherein said thin film transistor of each pixel has a gate region, said gate region of each transistor being disposed under a corresponding one of said address lines.

5. A liquid crystal display unit as claimed in claim 2, wherein said thin film transistor of each pixel has a source region, said source region of each of said transistors being disposed under and connected electrically to a corresponding one of said signal lines.

6. A liquid crystal display unit as claimed in claim 1, wherein one of said signal lines is disposed along side each column of said matrix of pixels.

7. A liquid crystal display unit as claimed in claim 1, wherein one of said address lines is disposed along side each row of said matrix of pixels.

8. A liquid crystal display unit as claimed in claim 2, wherein said thin film transistor of each pixel is an ultrathin film transistor having a high mobility.

13. A device as claimed in claim 1, further comprising a storage capacitor having a pair of terminals, one terminal being connected to the respective switching device.

14. A device as claimed in claim 13, wherein said storage capacitor is formed between each of a portion of the transparent pixel electrode and a portion of one of the plurality of address lines.

9. A liquid crystal display device, comprising:

a plurality of pixels arranged in a matrix, each pixel comprising;

a picture element electrode,

a storage capacitor for holding a signal voltage to be applied to the picture element electrode and

a switching transistor connected to the picture element electrode and a switching transistor connected to the picture element electrode, said switching transistor having a gate electrode, a gate insulating layer, and a semiconductor thin film defining a source, channel, and drain regions of the transistors;

first signal lines connected to supply a first signal to each of odd rows of said pixels in said matrix;

second signal lines connected to supply a second signal to each of even rows of said pixels in said matrix;

address lines connected to select alternate rows of said pixels in said matrix; and

electrode leads disposed between two adjacent address lines, each electrode lead defining one of electrodes of the storage capacitor and being connected commonly to the adjacent rows of the pixels.

10. A liquid crystal display unit as claimed in claim 9, wherein said electrode leads receive a fixed potential.

11. A liquid crystal display device as claimed in claim 9, wherein said switching transistor is formed under the first or second signal lines.

12. A liquid crystal display device as claimed in claim 9, wherein said storage capacitor is formed by the electrode lead, an extension of the gate insulation film, and an extension of the semiconductor thin film.

15. A liquid crystal display device, comprising:

a plurality of pixels arranged in a matrix, each pixel comprising a picture electrode, a switching transistor electrically connected to the picture element electrode, and a storage capacitor for holding a signal voltage to be applied to the picture element electrode;

address lines associated with rows of the pixels in the matrix; and

signal lines associated with columns of the pixels in the matrix, each signal line being formed over the switching transistor, wherein said picture element electrode and said signal line associated with it are situated in overlapping relationship with one another.

16. A liquid crystal display device as claimed in claim 15, wherein said signal line extends over a portion of the picture element electrode.

17. A liquid crystal display device, comprising:

a plurality of pixels arranged in a matrix, each pixel comprising a picture electrode, a switching transistor electrically connected to the picture element electrode, and a storage capacitor for holding a signal voltage to be applied to the picture element electrode;

address lines associated with rows of the pixels in the matrix; and

signal lines associated with columns of the pixels in the matrix, each signal line being formed over the switching transistor, said signal lines comprising a first signal line for supplying a first signal to odd-numbered rows of the pixels, and a second signal line for supplying a second signal to even-numbered rows of the pixels, said first and second signal lines being disposed in both sides of the pixels.

18. A liquid crystal display device, comprising:

a plurality of pixels arranged in a matrix, each pixel comprising a picture electrode, a switching transistor electrically connected to the picture element electrode, and a storage capacitor for holding a signal voltage to be applied to the picture element electrode;

address lines associated with rows of the pixels in the matrix; and

signal lines associated with columns of the pixels in the matrix, each signal line being formed over the switching transistor,

said switching transistor comprising a semiconductor thin film which defines source, channel, and drain regions of the transistor;

an electrode lead disposed between two adjacent address lines, each electrode lead defining one electrode of the storage, said storage capacitor being formed between said electrode lead and an extension of the semiconductor thin film of the switching transistor, said switching transistor comprising an insulating film deposited on the semiconductor thin film, said insulating film defining a dielectric material for the storage capacitor.