Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2001-09-17
2003-12-09
Flynn, Nathan J. (Department: 2826)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S151000, C349S152000, C349S155000, C349S143000, C349S153000, C349S149000, C349S150000
Reexamination Certificate
active
06661490
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to an electro-optical device and an electronic apparatus, and more specifically, it relates to the technology suitable for a liquid crystal display device having an active element.
2. Description of the Related Art
Generally, a liquid crystal display panel constituting a liquid crystal display comprises a liquid crystal sealed between two substrates, a plurality of electrodes disposed on inner surfaces of the two substrates facing each other, and optical modulation modes according to the voltage applied between electrodes are realized for each pixel area formed of a pair of electrodes facing each other and the liquid crystal disposed therebetween.
The current mainstream liquid crystal display panels are active matrix liquid crystal display panels that produce the highest screen quality. In this active matrix liquid crystal display panel, a pixel electrode formed on each of the above pixel areas is connected to wires via an active element including a thin film transistor (TFT) and a thin film diode (TFD) having the non-linear current-voltage characteristic.
Some liquid crystal display panels have a semiconductor circuit to supply a predetermined electric potential to a plurality of electrodes in a liquid crystal sealed area formed on a substrate surface portion outside the liquid crystal sealed area that is sealed with a sealing material or the like. This semiconductor circuit is connected to an input terminal formed on a substrate end portion and a wire connected to the electrodes, and outputs a drive electric potential to a plurality of electrodes based on a power source electric potential and a control signal supplied to the input terminal. The semiconductor circuit comprises semiconductor ICs mounted on the surface of the substrates, or comprises a circuit pattern formed directly on the surface of the substrates using thin film deposition technology.
In the above active matrix liquid crystal display, a problem occurs, in that the active element easily causes a dielectric breakdown by the static electricity accumulated in a liquid crystal panel manufacturing process generally due to a low electrostatic withstand voltage of the active element, and thus the active element does not perform its function.
FIG. 8
shows a liquid crystal display panel
100
having a structure to prevent the dielectric breakdown of the above active element. In this liquid crystal display panel
100
, an element substrate
110
is bonded to an opposing substrate
120
via a sealing material not shown in the figure, and a liquid crystal is sealed inside the sealing material. A plurality of data lines
111
continuously disposed in a striped manner are formed on the surface of the element substrate
110
, and a plurality of pixel electrodes
112
are respectively connected to the data lines
111
via a MIM element not shown in the figure (a diode (two-terminal) element) having a “metal-insulator-metal” structure with a non-linear current-voltage characteristic.
A substrate expansion portion
110
a
expanding from an outer edge portion of the opposing substrate
120
is disposed on the element substrate
110
, the data line
111
is extended onto the surface of the substrate expansion portion
110
a,
and a connection portion
111
a connected to a semiconductor IC
115
indicated by a one-dot chain line in the figure is disposed on a tip of the data line
111
. A plurality of input terminals
113
are formed on the outer edge portion of the substrate expansion portion
110
a,
and the input terminal
113
is also connected to the semiconductor IC
115
.
On the other hand, a plurality of scanning lines
121
disposed parallel to each other and a plurality of opposing electrodes
122
parallel to each other extending in a direction orthogonal to the data lines
111
and connected to these scanning lines
121
are disposed on the opposing substrate
120
. The opposing electrode
122
is intersected with the pixel electrode, and the intersected portion forms the pixel area. An area with a plurality of pixel areas P shown in
FIG. 9
arrayed in a matrix is referred to as a liquid crystal drive area S. A connection portion
125
a
disposed on the tip of the scanning line
121
is connected to the semiconductor IC
125
mounted on the substrate expansion portion
120
a
of the opposing substrate
120
. A plurality of input terminals
123
connected to the above semiconductor IC
125
are formed on the outer edge portion of the substrate expansion portion
120
a.
In this liquid crystal display panel
100
, a dummy electrode
117
having a U-shape in plan view is disposed on the surface of the element substrate
110
. The dummy electrode
117
comprises a pair of dummy electrode units
117
a,
117
b
extending parallel to each data line
111
on both right and left sides of the liquid crystal drive area S, and a dummy electrode unit
117
c
passing between the connection portion
111
a
of the data line
111
and the input terminal
113
. The dummy electrode
117
is integrally formed so that the dummy electrode portions
117
a,
117
b,
117
c
are connected to each other.
In this liquid crystal display panel
100
, static electricity accumulated in the manufacturing process is transmitted along the dummy electrode
117
since the dummy electrode
117
is formed, and thus the static electricity is less easily transmitted to the data line
111
, and thus the dielectric breakdown of the MIM element can be reduced.
However, although the probability of a dielectric breakdown occurrence of the MIM element is reduced when the above dummy electrode
117
is formed, a pixel defect Q (a white defect attributable to a short circuit defect in a MIM element) can occur along the data line
111
on the dummy electrode unit
117
b
as shown in FIG.
9
. This pixel defect Q occurs in a portion close to the dummy electrode unit
117
c
when viewed in the extending direction of the data line
111
, and occurs in a more extensive range toward the opposite side of the dummy electrode unit
117
c
closer to the dummy electrode unit
117
b.
Such a pixel defect Q adversely affects the yield of the product because the defect cannot be discovered until a lighting inspection is carried out after the panel assembly process.
The present invention has been made in light of the above problems and the object of the present invention is to reduce the above pixel defects by providing an electro-optical device with countermeasures for the static electricity.
SUMMARY OF THE INVENTION
In order to solve the above problems, an electro-optical device according to the present invention comprises an electro-optical substance disposed between a first substrate and a second substrate, and is characterized in that the first substrate comprises a plurality of first wires extending in a predetermined direction, pixel electrodes connected to the first wires via an active element, an input terminal, and a semiconductor circuit connected to the first wires and the input terminal, the second substrate comprises opposing electrodes disposed facing the pixel electrodes and second wires connected to the opposing electrode at one side in a direction substantially orthogonal to the predetermined direction, an area where the pixel electrodes that face the opposing electrodes via the electro-optical substance is formed into a drive area, and the first substrate further comprises a dummy electrode having a dummy electrode unit extending along the first wires on the side opposite to the second wires in the drive area and a dummy electrode unit passing between the first wires and the input terminal formed continuously to each other.
The dummy electrode is not formed on the second wiring side of the drive area.
A second dummy electrode comprising a dummy electrode unit extending along the first wires on the second wire side of the drive area and a dummy electrode unit passing between the first wires and the input terminal formed continuously thereto is separated from the dumm
Erdem Fazli
Flynn Nathan J.
Harness & Dickey & Pierce P.L.C.
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