Active solid-state devices (e.g. – transistors – solid-state diode – Non-single crystal – or recrystallized – semiconductor... – Amorphous semiconductor material
Reexamination Certificate
2002-06-03
2004-08-10
Tran, Thien F (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Non-single crystal, or recrystallized, semiconductor...
Amorphous semiconductor material
C257S072000, C257S347000
Reexamination Certificate
active
06774398
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin film transistor array panel, in particular to a visual inspection means and a method of performing visual inspection in a thin film transistor array panel having a gate driving circuit integrated therein.
2. Description of the Related Art
A thin film transistor array panel is used as a circuit panel for driving each of pixels independently in a liquid crystal display (LCD) or an organic electroluminescence (EL) display, etc. In the thin film transistor panel, a scan signal wire or a gate wire for transferring a scan signal and an image signal wire or a data wire for transferring an image signal are formed. Also, a thin film transistor connected to the gate wire and the data wire, a pixel electrode connected to the thin film transistor, a gate insulating layer for covering and insulating the gate wire and a passivation layer for covering and for insulating the thin film transistor and the data wire are formed therein. The thin film transistor comprises a semiconductor layer forming a channel together with a gate electrode that is a part of the gate wire, a source electrode and a drain electrode that is a part of the data wire, the gate insulating layer and the passivation layer. The thin film transistor is a switching element that transmits the image signal transmitted through the data wire to the pixel electrode depending on the scan signal transmitted through the gate wire.
An LCD is a representative of display devices using such a thin film transistor panel, and especially a middle-small type LCD, such as a reflection type or semi-transmittance type mostly, employs a COG (chip on glass) type. In this case, visual inspection (VI) or gross test (GT) is done before a COG IC mounting process so as to save expensive COG ICs, polarizers and a compensating film and to increase the yield. It is difficult to apply GT to a practical process since the test requires an expensive equipment and furthermore a long processing time. In addition, a currently available VI is performed after forming a wire for inspection to connect gate lines and data lines between the COG terminals or to its opposite side to perform the VI, then a diamond-cutting is done together with a panel or a laser-cutting is done to divide the wire for inspection. In this case, in such a cutting process, pollutant particles are generated or the wire is corroded through a cut side thereof, and thereby degrading the reliability.
In the meanwhile, TFT panels can be manufactured by a method in which a driving integrated circuit is directly formed on the thin film transistor, either partially or as a whole. As such example, there are a poly silicon thin film transistor panel (Poly TFT Panel) and an amorphous driving integrated circuit panel (a-si IC Panel). In the method of directly forming the driving IC on the TFT panel as a whole, GT can be performed by the TFT itself. However, the method of directly forming only a portion of the driving IC on the TFT panel needs an expensive equipment to perform GT.
Furthermore, it is hard to employ a laser-cutting after inspection since the driving IC formed on the TFT works as impediments on laser-cutting and, due to forming the TFT panel and a color filter panel in a same size, a space for laser-cutting is not easy to obtain.
SUMMARY OF THE INVENTION
The present invention increases the reliability of a liquid crystal display by solving the problems.
The present invention provides a means for performing a visual inspection in a thin film transistor having a driving integrated circuit.
The present invention also provides methods for performing visual inspection in a thin film transistor having a driving integrated circuit.
In one aspect, the present invention provides a thin film transistor panel comprising a logic circuit for VI connected between a gate driving circuit and a gate line to apply a gate inspection signal.
In detail, a thin film transistor panel includes an insulating substrate having a display area and a surrounding area, a first signal line formed on the insulating substrate, a second signal line formed on the insulating substrate and insulated with and intersecting the first signal line to define the display area, a plurality of driving signal lines formed on the surrounding area of the insulating substrate and connected to a V
off
voltage applying terminal, a plurality of inspection signal lines formed on the surrounding area of the insulating substrate, a first thin film transistor for inspection having a drain electrode coupled to the first signal line, a source electrode coupled to any one of the inspection signal lines and a gate electrode coupled to any one of the driving signal lines, and a second thin film transistor for inspection having a drain electrode coupled to the second signal line, a source electrode coupled to any one of the inspection signal lines and a gate electrode coupled to any one of the driving signal lines.
The inspection signal line connected to the second thin film transistor for inspection comprises a first inspection signal line and a second inspection signal line. The second thin film transistor for inspection may be alternatingly connected to the first inspection signal line and the second inspection signal line. The first inspection signal line connected to the first thin film transistor for inspection comprise third and fourth inspection signal lines. The first thin film transistor for inspection may be alternatingly connected to the third inspection signal line and the fourth inspection signal line.
In addition, the inspection signal line connected to the second thin film transistor for inspection comprises first, second and third inspection signal lines. The second thin film transistor for inspection may be connected to the first, second and third inspection signal lines in turn. The inspection signal line connected to the first thin film transistor for inspection comprises fourth and fifth inspection signal lines. The first thin film transistor for inspection is alternatingly connected to the fourth and fifth inspection signal lines.
The driving signal line connected to the second thin film transistor for inspection comprises first, second and third driving signal lines. The second thin film transistor for inspection may be connected to the first, second and third driving signal lines in turn.
A detailed structure of a thin film transistor panel having a thin film transistor for inspection is as below.
The thin film transistor panel includes an insulating substrate having a display area and a surrounding area, a gate line formed on the insulating substrate, a data driving signal line formed on the surrounding area of the insulating substrate, a data inspection signal line formed on the surrounding area of the insulating area, a gate insulating layer formed on the gate lines, the data driving signal lines and the data inspection signal lines, a semiconductor pattern formed on the gate insulating layer, at least a portion thereof overlapping the data driving signal lines, first and second ohmic contact layers formed on the first semiconductor pattern and exposing therebetween a portion of the first semiconductor pattern corresponding to the data driving signal lines, a data line formed on the gate insulating layer and intersecting the gate lines to define the display area, at least a portion thereof being formed on the second ohmic contact layer, a first electrode for inspection formed on the gate insulating layer, at least a portion thereof being formed on the first ohmic contact layer, a passivation layer formed on the data lines and the first electrode for inspection, and a first connection portion formed on the passivation layer and connecting the data inspection signal lines and the first electrode for inspection.
The thin film transistor panel may further include a gate driving signal line formed on the surrounding area of the insulating substrate, a gate inspection signal line formed on the surrounding area of the insulating substrate
Jang Yong-Kyu
Jeon Jin
Lee Won-Kyu
Cantor & Colburn LLP
Tran Thien F
LandOfFree
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