Patent Application
20090294771
1. Field of the Invention
The present invention relates to an array substrate and a method of manufacturing the array substrate. More particularly, the present invention relates to an array substrate capable of a defect inspection process after manufacturing the array substrate, and a method of manufacturing the array substrate.
2. Description of the Related Art
Liquid Crystal Displays (“LCDs”) are devices which display images by applying an electric field to a liquid crystal layer disposed between two panels, and regulating the strength of the electric field to adjust a transmittance of light which passes through the liquid crystal layer.
Conventional LCDs include a panel unit having pixels including switching elements and display signal lines, and a gate driving Integrated Circuit (“IC”) which transmits gate signals to gate lines among the display signal lines to turn on and off the switching elements of the pixels, a gray voltage generator which generates a plurality of gray voltages, a data driving IC which applies data voltages to data lines among the display signal lines, and a signal controller which controls the components.
The signal controller and the gray voltage generator are disposed on a printed circuit board (“PCB”) located outside of the panel assembly. The driving IC is mounted on a flexible Tape Carrier Package (“TCP”) located between the PCB and the panel assembly. Generally, two PCBs are provided. In this case, the two PCBs are disposed at upper and left sides of the panel assembly, and the upper and left side PCBs are referred to as gate and data PCBs, respectively. The gate driving IC is disposed between the gate PCB and the panel assembly, and the data driving IC is disposed between the data PCB and the panel assembly. The tape carrier package (“TCP”) is used to dispose both driving ICs. The gate and data driving ICs receive signals from the gate and data PCBs, respectively.
A Chip On Glass (“COG”) type device which attaches a driving IC directly onto the glass substrate using the anisotropic conducting film (“ACF”) without TCP is used to reduce costs. Generally, mobile thin film transistor (“TFT”) LCD devices and compact size TFT LCD devices are produced using the COG type devices.
In order to detect defects such as disconnections and short-circuits during the production of the display device, various test processes are performed. For example, an array test, a visual inspection (“VI”) test, a gross test, and a module test are performed. For these tests, end portions of the gate lines and the data lines are formed as pads having wide ends, in order to improve a contacting property to an external device. In the array test and VI test, the gate lines and the source lines are grouped by certain units (for example, 2G2D or 2G3D) and tested by applying test signals.
The present invention provides a substrate for a display panel of a display device to detect defect inspection more efficiently.
In an exemplary embodiment, the present invention provides a substrate for a display panel. The substrate including a base substrate, a plurality of first signal lines on the base substrate, the plurality of first signal lines extending in a first direction, a plurality of first signal pads on the base substrate corresponding to first end portions of the plurality of first signal lines, a first shorting bar on the base substrate corresponding to second end portions of the plurality of first signal lines which dissipates an electrostatic charge, the first shorting bar extending in a second direction different from the first direction. The substrate further includes a plurality of bridge lines on the base substrate disposed between the first signal line and the first shorting bar, which electrically connects the first signal line and the first shorting bar together.
According to an exemplary embodiment, the plurality of first signal lines includes a plurality of odd numbered first signal lines and a plurality of even numbered first signal lines electrically connected to the shorting bar.
According to an exemplary embodiment, the first shorting bar includes a first shorting bar line and a second shorting bar line each extended in a second direction parallel to each other, and the first shorting bar line and the second shorting bar line are connected to the plurality of odd and even numbered first signal lines, alternatively.
According to another exemplary embodiment, the plurality of first signal lines are formed on a different layer than the shorting bar, the shorting bar is formed simultaneously with gate metal layers.
According to an exemplary embodiment, the plurality of first signal lines corresponds to data lines that carry data signal into the panel.
According to an exemplary embodiment, the bridge lines are made of transparent conducting oxide including Indium Tin Oxide, Tin Oxide, and Indium Zinc Oxide.
According to an exemplary embodiment, the substrate further includes a first inspection contact hole which electrically connects the first signal line with the bridge line and a second inspection contact hole which electrically connects the shorting bar with the bridge line.
In another exemplary embodiment, the present invention provides a substrate for a display panel including a base substrate, a plurality of first signal lines on the base substrate, the plurality of first signal lines extending in a first direction, a plurality of first signal pads on the base substrate corresponding to first end portions of the plurality of first signal lines, a first shorting bar on the base substrate corresponding to second end portions of the plurality of first signal lines, which dissipates an electrostatic charge, the first shorting bar extending in a second direction different from the first direction, a plurality of bridge lines on the base substrate disposed between the first signal line and the first shorting bar which electrically connects the first signal and the first shorting bar, a plurality of data thin film transistor driving signal lines formed on the base substrate connected to a off voltage applying terminal, a data thin film transistor (“TFT”) for inspection having a source electrode coupled to the first signal line, a drain electrode coupled to any one of the first shorting bar and a gate electrode coupled to the data thin film transistor driving signal line.
In another exemplary embodiment, the present invention provides a display panel including a first base substrate, a plurality of first signal lines on the first base substrate, the plurality of first signal lines extending in a first direction, a plurality of first signal pads on the first base substrate corresponding to first end portions of the plurality of first signal lines, a first shorting bar on the base substrate corresponding to second end portions of the plurality of first signal lines, which dissipates an electrostatic charge, the first shorting bar extending in a second direction different from the first direction, a plurality of bridge lines on the base substrate disposed between the first signal line and the first shorting bar which electrically connects, a second base substrate opposite the first substrate, and a medium dam layer formed on the second substrate that fully overlaps the bridge lines of the first base substrate.
The above and/or other aspects, features, and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:
The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.
It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first thin film could be termed a second thin film, and, similarly, a second thin film could be termed a first thin film without departing from the teachings of the disclosure.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower”, can therefore, encompasses both an orientation of “lower” and “upper,” depending of the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Embodiments of the present invention are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present invention.
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
As shown in
Input pads 20, 33 are in contact with flexible films which are made of organic material transmit control signals, power signals, and data signals into the driving IC. Furthermore the driving IC drives at least one of the gate line 2 and data line 3. The gate driving IC 25 is connected to the gate line 2 so as to output a gate driving signal, and the data driving IC 35 is connected to the data line 3 so as to output a data signal.
Output pads 20, 30 provide driving signals one of the scan signals and data signals generated by the driving IC with the signal line and one of the gate line 2 and data line 3.
In the array test, according to an exemplary embodiment of the present invention, the odd numbered data lines and even numbered data lines alternate with each other, so that each of the odd numbered data lines is adjacent to each of the even numbered data lines, so that an electrical short defect may be detected between the odd numbered data lines and the even numbered data lines. Therefore, the even numbered gate lines are grouped and the odd numbered lines are grouped. The same process described above may also be applied to the VI process.
The above mentioned array test method is also applied to the gate line as the same method.
After the array test, shorting bar 50a, 50b in a gate pad region is disconnected from the gate line 2 for normal operation of the TFT LCD. According to an exemplary embodiment, glass cutting using a diamond cutting process through the glass cutting line is performed after the array test. Alternatively, according to another exemplary embodiment, an edge grinding process followed by the diamond glass cutting process may be performed.
In the event that the driver IC is directly mounted on the LCD panel, an inspection process is performed before the data driver is mounted on the LCD panel so as to inspect whether or not the LCD panel is operating normally. In detail, the shorting bar 50 is formed above the pad region of the TFT array substrate in order to conduct the defect inspection process including line defect, pixel defect, and so on. The shorting bar is finally disconnected from the signal line by laser trimming on a fixed width for driving individual driving signals into the signal line before attaching the driver IC. The driving IC is attached to the disconnected region. According to an exemplary embodiment, as the size of the TFT LCD device becomes smaller the space between the pad and the signal line becomes smaller, and defects in the signal line are generated due to the effect of the laser trimming process. During the laser trimming process, poor product reliability is caused by the production of polluted particles and the corrosion of metal lines through the cutting plane.
As shown in
Data driving ICs 35 are disposed directly on an upper side of the panel as a COG type device, sharing the power signal with each driving IC as a cascade type. In the current exemplary embodiment, COG type devices have driving ICs attached directly onto the glass substrate using the ACF. The COG type device also has flexible printing circuits (“FPCs”) that correspond to a single data driving IC 35. By sharing the specific signal (for example, power signal etc.), however, we can reduce the number of FPCs. Referring back to
Gate driving ICs 25, are mounted on a TCP 26 which is located between the PCB (not shown) and the panel assembly. Through TCP 26, a gate driving signal is transmitted into the panel assembly.
Shorting bar 50a, 50b is used for inspection purposes and is connected to a third end opposite the second end of the data line 3. As the resolution of the TFT LCD panel increases, however, the wiring in the pad region becomes complex due to the high level of integration required. Therefore, there is little or no room for piling up shorting bars in the pad region. In an exemplary embodiment of the invention, array test shorting bar 50a, 50b is connected to a third end opposite the second end of the data line 3, located on the opposite side of a data fan out region. By positioning the shorting bar 50a, 50b at this location, it is possible to have high manufacturing yield without defects during an array test. The shorting bar includes an odd shorting bar 50a which is connected to odd data lines 3 and even shorting bar 50b which is connected to even data lines 3. Both of the odd and even shorting bars 50a and 50b are arranged parallel to each other at a fixed interval. In other exemplary embodiments of the invention, shorting bar 50a, 50b is arranged in the data pad region near the fan out region as shown in
Referring to
After the end of array testing, bridge line 60 is disconnected from the data lines 3 through a glass cutting operation to ensure correct operation of the TFT LCD panel. In the event that the data lines 3 and shorting bar 50a, 50b are made of the same metal layers, the cutting edge plane is easily corroded after a laser trimming operation due to the exposure to moisture. Using the bridge line 60, however, the metal corrosion problem could be solved owing to the ITO metal characteristics having strong resistance to corrosion. That is, the cutting line (depicted in
Thus, shorting bar 50a, 50b that is connected to data line 3 through the bridge line 60 made of transparent conducting oxide such as ITO and IZO prohibits the occurrence of static electricity during the manufacturing method of a TFT LCD. Shorting bar 50a, 50b which enables wiring defect testing after manufacturing the TFT array panel allows for easy inspection. After the wiring defect inspection process, the bridge line 60, which links data line 3 to shorting bar 50a, 50b, is scribed using a diamond cutting operation to disconnect shorting bar 50a, 50b with data line 3 electrically for normal operation of the TFT LCD panel.
As shown in
Further, as shown in
In an exemplary embodiment of the invention, the separate color filter array panel 150 which is opposite the TFT array panel 160 with a fixed gap thickness of approximately 5 μm, includes a black matrix 130 made of an organic or metal film, common transparent electrode 140, for example, ITO, IZO, and medium dam layer 80 having a thickness smaller than a cell gap.
The TFT array panel 160 having a completed wiring defect test and color filter array panel 150 which includes a column spacer as a buffer layer in the bridge line region are assembled. And, in accordance with the cutting line the TFT LCD panel is seperated into unit panels using a diamond cutting operation.
Thus, referring now back to
Referring to
Data driving ICs 35 are disposed directly on an upper side of the panel as a COG type sharing the power signal with each of the driving ICs as a cascade type. Gate driving ICs 25 are mounted on a TCP 26 which is located between the PCB 36 and the panel assembly.
Shorting bar 50a, 50b for inspection is connected to a third end opposite the second end of the data line 3. In the current exemplary embodiment of the invention, array test shorting bar 50a, 50b is connected to a third end opposite the second end of the data line 3, which is the opposite side of the data fan out region. With this configuration it is possible to have high manufacturing yield without defects during array testing. The shorting bar includes odd shorting bar 50a which is connected to odd data lines 3 and even shorting bar 50b which is connected to even data lines 3. Both the odd and even shorting bars 50a and 50b in some exemplary embodiments of the present invention are arranged parallel to each other at a fixed interval.
The metal layer including data lines 3 are different from shorting bars 50a, 50b which are connected to the data lines 3. Therefore, the ITO bridge line 60 links the data lines 3 with the shorting bar 50a, 50b for array testing. After the array testing is completed, the ITO bridge line 60 is disconnected with data lines 3 using a scribing operation to ensure correct operation of the TFT LCD panel. Using the ITO bridge line 60, however, the metal corrosion problem could be solved owing to the ITO metal characteristics having strong resistance to corrosion. The gate metal layer includes Cr, MoW, Cr/Al, Cu, Al(Nd), Mo/Al, Mo/Al(Nd), Cr/Al(Nd).
A data TFT 70 for inspection is connected to a third end opposite the second end of the data line 3 in series with the ITO bridge line 60. The data TFT 70 is also connected to a shorting bar 50a, 50b and data TFT driving signal line 75. The data line 3, shorting bar 50a, 50b, and the data driving signal line 75 are connected to a source electrode, drain electrode, and gate electrode of the data TFT 70, respectively. The data TFT driving signal line 75 is connected to a data Voff pad 76. All the gate electrodes of the data TFTs 70 are connected to the data Voff pad 76. The Voff pad 76 is kept constant as Voff voltages in a later process. After the array test, the shorting bars 50a, 50b are disconnected with data lines 3 by a diamond-cutting operation in ITO bridge line 60 region for normal TFT LCD operation. The possibility of incoming static electricity into the panel, however, still exists through the cutting edge of the metal wiring. Thus, the data TFTs 70 are always in an off state (i.e., a disconnection state). The data TFTs 70 function as a fail safe for unpredictable inflow of static electricity that causes abnormal operation of a TFT LCD.
While the present invention has been shown and described with reference to some exemplary embodiments thereof, it should by understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-52202 | Jun 2008 | KR | national |
