IP Library Granted Patent US 7,995,172
Granted Patent B2
US 7,995,172 · App. 12/227,848 · Granted Aug 9, 2011

Semitransparent liquid crystal display

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Quick Facts
Patent No.
US 7,995,172
App. No.
12/227,848
Granted
Aug 9, 2011
Kind
B2
Abstract

An electrically-floating light shielding film is formed on a glass substrate, and a signal line is formed above the light shielding film via a gate insulating film. The light shielding film is formed along the signal line, and has a width larger than that of the signal line. On an interlayer insulating film that covers the signal line, transparent electrodes of neighboring pixels are formed, and a reflective electrode extending from the transparent electrode has a frame portion disposed along the signal line. The reflective electrode is formed the interlayer insulating film. The light shielding film does not overlap the transparent electrode in a plan-view perspective and overlaps the reflective portion in a plan-view perspective. The signal line does not overlap the reflective electrode in a plan-view perspective. Hence, a semitransparent liquid crystal display device that suppresses vertical crosstalk and as well maintains a high aperture ratio is obtained.

Claims (61)

1. A semitransparent liquid crystal display device, comprising:

signal lines and scanning lines disposed in a matrix form;

a pixel electrode formed in each of pixel regions defined by said signal lines and said scanning lines, said pixel electrode including a transparent electrode and a reflective electrode; and

a thin film transistor connected to each pixel electrode,

wherein said semitransparent liquid crystal display device comprises:

a transparent insulating substrate;

a first metal film and a scanning line formed on said transparent insulating substrate;

a first insulating film formed on said transparent substrate and covers said first metal film and said scanning line;

a signal line formed above said first metal film via said first insulating film;

a second insulating film formed on said first insulating film and covers said signal line;

a transparent electrode formed on said second insulating film;

a third insulating film formed to cover a portion of said transparent electrode and said second insulating film; and

a second metal film formed on said third insulating film,

wherein said first metal film does not overlap said transparent electrode in a plan-view perspective and overlaps, at its edge, said second metal film in a plan-view perspective,

wherein said signal line overlaps neither said second metal film nor said transparent electrode in a plan-view perspective, and overlaps, at least a portion thereof, said first metal film in a plan-view perspective, and

wherein a slit is formed in a portion of said first metal film.

2. The semitransparent liquid crystal display device according to claim 1 , wherein said first metal film comprises a metal film that has a light shielding property and is electrically-floating.

3. The semitransparent liquid crystal display device according to claim 2 , wherein said second metal film comprises a metal film having a light shielding property.

4. The semitransparent liquid crystal display device according to claim 2 , wherein a width of said signal line is less than a width of said first metal film.

5. The semitransparent liquid crystal display device according to claim 2 , wherein said first metal film extends along said signal line.

6. The semitransparent liquid crystal display device according to claim 2 , wherein said second metal film comprises said reflective electrode connected to said transparent electrode.

7. The semitransparent liquid crystal display device according to claim 2 , wherein a storage capacitance electrode that forms storage capacitance is formed on said transparent insulating substrate under said reflective electrode.

8. The semitransparent liquid crystal display device according to claim 1 , wherein said second metal film comprises a metal film having a light shielding property.

9. The semitransparent liquid crystal display device according to claim 1 , wherein a width of said signal line is less than a width of said first metal film.

10. The semitransparent liquid crystal display device according to claim 1 , wherein said first metal film extends along said signal line.

11. The semitransparent liquid crystal display device according to claim 10 , wherein said portion of said first metal film overlaps said signal line in a plan-view perspective.

12. The semitransparent liquid crystal display device according to claim 1 , wherein said second metal film comprises said reflective electrode that is connected to said transparent electrode.

13. The semitransparent liquid crystal display device according to claim 12 , wherein said second metal film comprises a frame portion of said reflective electrode, said frame portion being formed along a circumference of said transparent electrode.

14. The semitransparent liquid crystal display device according to claim 1 , wherein a storage capacitance electrode that forms storage capacitance is formed on said film transparent insulating substrate under said reflective electrode.

15. The semitransparent liquid crystal display device according to claim 1 , wherein said portion of said first metal film overlaps said signal line in a plan-view perspective.

16. A semitransparent liquid crystal display device, comprising:

signal lines and scanning lines disposed in a matrix form;

a pixel electrode formed in each of pixel regions defined by said signal lines and said scanning lines, said pixel electrode including a transparent electrode and a reflective electrode; and

a thin film transistor connected to each pixel electrode, wherein said semitransparent liquid crystal display device comprises:

a transparent insulating substrate;

a first metal film and a scanning line formed on said transparent insulating substrate;

a first insulating film formed on said transparent substrate and covers said first metal film and said scanning line;

a signal line formed above said first metal film via said first insulating film;

a second insulating film formed on said first insulating film and covers said signal line;

a transparent electrode formed on said second insulating film;

a third insulating film formed to cover a portion of said transparent electrode and said second insulating film; and

a second metal film formed on said third insulating film,

wherein said first metal film does not overlap said transparent electrode in a plan-view perspective and overlaps, at its edge, said second metal film in a plan-view perspective,

wherein said signal line overlaps neither said second metal film nor said transparent electrode in a plan-view perspective, and overlaps, at least a portion thereof, said first metal film in a plan-view perspective, and

wherein (parasitic capacitance between signal line and pixel electrode)/(liquid crystal capacitance+storage capacitance) is 0.05 or less.

17. A semitransparent liquid crystal display device, comprising:

signal lines and scanning lines disposed in a matrix form;

a pixel electrode formed in each of pixel regions defined by said signal lines and said scanning lines, said pixel electrode including a transparent electrode and a reflective electrode; and

a thin film transistor connected to each pixel electrode, wherein said semitransparent liquid crystal display device comprises:

a transparent insulating substrate;

a first metal film and a scanning line formed on said transparent insulating substrate;

a first insulating film formed on said transparent substrate and covers said first metal film and said scanning line;

a signal line formed above said first metal film via said first insulating film;

a second insulating film formed on said first insulating film and covers said signal line;

a transparent electrode formed on said second insulating film;

a third insulating film formed to cover a portion of said transparent electrode and said second insulating film; and

a second metal film formed on said third insulating film,

wherein said first metal film does not overlap said transparent electrode in a plan-view perspective and overlaps, at its edge, said second metal film in a plan-view perspective,

wherein said signal line overlaps neither said second metal film nor said transparent electrode in a plan-view perspective, and overlaps, at least a portion thereof, said first metal film in a plan-view perspective,

wherein said first metal film comprises a metal film that has a light shielding property and is electrically-floating, and

wherein (parasitic capacitance between signal line and pixel electrode)/(liquid crystal capacitance+storage capacitance) is 0.05 or less.

Assignments (2)
CHANGE OF NAME Recorded Nov 8, 2011
From: NEC LCD TECHNOLOGIES, LTD.
To: NLT TECHNOLOGIES, LTD.
Reel/Frame 027189/0669 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 8, 2009
From: ISHII, TOSHIYA
To: NEC LCD TECHNOLOGIES, LTD.
Reel/Frame 022101/0549 →