JPH0815713A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To complement the electrical resistance difference between liquid crystal driving power source lines and to obtain a uniform display by providing the liquid crystal driving power source lines of the small resistance of display electrode patterns with regulating resistors. CONSTITUTION:A rectangular display screen 18 of a liquid crystal display panel 14 is composed by sticking a glass substrate 15 for scanning and a glass substrate 16 for signals to each other. The signal side liquid crystal driving power source lines 19, 20 are formed in the regions exclusive of the display screen 18 of the glass substrate 16 for signals. Wiring patterns 26 are formed on a printed circuit board 23. A resistor chip 27 which is the regulating resistor is disposed on wiring patterns 26 between a part, i.e., IC chip 24, of the wiring patterns 26 and a connector 25. The wiring resistance difference generated in the display electrode patterns is corrected by the resistance chip 27 according to the liquid crystal display panel 14 provided with such printed circuit board 23. As a result, the contrast differences are no longer generated between the individual liquid crystal display panels 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix driving based on a voltage averaging method for a liquid crystal display panel having two rectangular display screens arranged side by side with a display electrode pattern made of a transparent conductive film. The present invention relates to a method for manufacturing a liquid crystal display device in which a signal side (segment side) liquid crystal drive power source line is provided.

[0002]

2. Description of the Related Art In a liquid crystal display device, a pair of rectangular plate-shaped glass substrates are prepared, a strip-shaped display electrode pattern made of, for example, indium tin oxide (ITO) is formed on both glass substrates, and each display is further formed. This can be obtained by forming an alignment film on the electrode pattern, interposing a liquid crystal layer between these alignment films, sealing the peripheral portion of the display region with a sealant, and then bonding the peripheral region. The pair of glass substrates are a scanning (common side) glass substrate and a signal (segment side) glass substrate, respectively.

In manufacturing the above liquid crystal display device,
With respect to the scanning glass substrate or the signal glass substrate on which the strip-shaped ITO display electrodes are arranged, the ITO layer is formed over the entire one main surface of each substrate and then etched to form a display electrode pattern.

A method for producing the signal glass substrate will be described below with reference to FIGS. First, FIG. 4 shows the master glass substrate 1 which is a source of the signal glass substrate, and FIG. 5 is a sectional view taken along the section line AA shown in FIG.

In order to improve mass productivity, two signal glass substrates 1a and 1b are obtained from this one master glass substrate 1. Also, this master glass substrate 1
Has an ITO layer 2 provided over the entire one main surface thereof, and a method of forming this ITO layer 2 will be described with reference to sputter deposition shown in FIG.

FIG. 1 shows the positional relationship between the sputter vapor deposition target 3 and the master glass substrate 1 for film formation, and 4 is a transport carrier on which the master glass substrate 1 is mounted. The sputter vapor deposition target 3 is a target made of ITO. The target 3 is struck by argon or the like to evaporate target atoms, and the carrier 4 is moved in the direction of arrow B with respect to the fixed target 3. , The entire surface of the master glass substrate 1 is vapor-deposited. In the actual manufacturing, the transport carrier 4 in which many master glass substrates 1 are arrayed passes through the fixed target 3, and along with this, the individual master glass substrates 1 are sequentially deposited.

After the ITO layer 2 is formed on the master glass substrate 1 by the sputter deposition having the above structure, the ITO layer 2 is formed.
The layer 2 was formed with a display electrode pattern as shown in FIG. 7 by a conventionally known etching technique. FIG. 2 is a plan view of the master glass substrate 1 having a pattern of display electrodes.
Corresponding to the signal glass substrates 1a and 1b, the same display electrode patterns 5a and 5b are provided above and below so that two liquid crystal display panels can be obtained.

In the above example, one master glass substrate 1 provided with the ITO layer 2 over the entire main surface is divided, and liquid crystal driving power supply lines are further provided on the individual signal glass substrates 1a and 1b. However, as another example, a case where the liquid crystal drive power supply line is provided before dividing the glass substrate will be described below.

For example, COG (chip on glass)
In the method, two signal glass substrates are obtained from one master glass substrate in order to improve mass productivity. The master glass substrate has an ITO layer and a Cr layer over the entire one main surface. A laminated body in which an Al layer is sequentially formed is provided, and this laminated body is formed by sputter deposition as described with reference to FIG.

That is, the target 3 for sputter deposition is IT
A target composed of O, Cr or Al,
Argon or the like is struck on the target 3 to evaporate the target atoms and form the above laminated body on the master glass substrate.

After this sputter deposition, a wiring pattern as shown in FIG. 8 is formed on the laminated body by a conventionally known etching technique. This figure is a plan view of the master glass substrate 6 having a wiring pattern, and the same display electrode patterns 7a and 7b are provided on the upper and lower sides so that two liquid crystal display panels can be obtained. In the figure, the wiring pattern in the white area is made of ITO layer, and the wiring pattern in the black area is IT.
It is composed of a laminated body of an O layer, a Cr layer and an Al layer.

Next, FIG. 9 shows a circuit diagram of a voltage averaging method for driving the liquid crystal display device. This voltage averaging method is a method of averaging the voltages at half-selected points and non-selected points during matrix driving, and is generally adopted in today's liquid crystal display devices. The condition that the display contrast is the best by the driving bias number a (a = √N
+1) has been decided.

As shown in FIG. 9, 8 is an operational amplifier for stabilizing the potential in resistance division, 9 is a capacitor, and two selection potentials V0 and V5 are provided in order to obtain 6 bias voltages by resistance division. By inserting five resistors (4 R and 1 (a-4) R) in series between and, four non-selection potentials V1, V2, V3, V4 are obtained, Each of these potentials (V0, V1, V2, V3, V4,
V5) is supplied to the liquid crystal driver as a liquid crystal driving voltage.

Further, according to the above voltage averaging method, when the number of scanning electrodes increases to, for example, about 400, parallel scanning of 1/200 duty drive is required to improve contrast and the like. Therefore, the display electrode is divided at the center of the screen, and both divided screens are separately scanned.

Thus, in the drive circuit having the above structure,
The electrodes COM for scanning (common side) have V0, V1 and V
4 and V5 are applied, and V0, V2, V3 and V5 are applied to the other signal (segment side) electrode SEG,
Further, V0 and V5 are on-voltages, while V2 and V3 are off-voltages. Further, since an AC voltage is applied for scanning and signals, when V0 and V2 are applied as positive, V3 and V5 are applied as negative. Since the display electrodes are divided at the center of the screen, there are two types of electrodes SEG, SEG-U located above and SEG-D located below.

[0016]

[Problems to be Solved by the Invention]
When the ITO layer 2 and the above-mentioned laminated body are formed by the sputter deposition of, as shown in FIG. 5, in the master glass substrates 1 and 6, the thickness of the ITO layer 2 and the end portion of the laminated body is larger than the thickness of the central portion. The display electrode patterns 5a and 5b and the display electrode patterns 7a and 7b are reduced in size.
The thickness of the electrode pattern of
There is a wiring resistance difference between the two divided display screens of each display electrode pattern 5a, 5b (or each display electrode pattern 7a, 7b), and as a result, a contrast difference occurs between the two divided display screens. However, there is a problem that a uniform display cannot be obtained.

Therefore, it is an object of the present invention to eliminate the contrast difference on the liquid crystal display due to the wiring resistance difference of the display electrode pattern, and to obtain a uniform display with high quality and high reliability. It is to provide a method of manufacturing a device.

[0018]

According to a first aspect of the invention, a transparent conductive film is formed on a master glass substrate by sputter deposition, and the transparent conductive film is etched to form two rectangular display screens in parallel. A plurality of liquid crystal display panels are provided with display electrode patterns of a predetermined shape, and liquid crystal driving power supply lines for matrix driving based on a voltage averaging method using a plurality of bias voltages by resistance division are provided in the rectangular shape. On both outer sides of the opposite side of the shape display screen,
Provided so as to be electrically conductive with the display electrode pattern,
Next, the master glass substrate is divided corresponding to each liquid crystal display panel, each liquid crystal display panel is constituted by the divided individual glass substrates, and then the liquid crystal for arranging the liquid crystal drive power source on the liquid crystal display panel. In the method of manufacturing a display device, an adjustment resistor is connected to a liquid crystal driving power supply line which is arranged in one of the two rectangular display screens of the liquid crystal display panel having a smaller electric resistance value between opposite sides of the rectangular display screen. Then
It is characterized in that it includes a resistance adjusting step for balancing the electric resistance value between the opposite sides of the other rectangular display screen.

According to a second aspect of the present invention, a plurality of liquid crystal display panels in which two rectangular display screens are arranged side by side by forming a transparent conductive film on a master glass substrate by sputtering deposition and etching the transparent conductive film. A display electrode pattern of a predetermined shape is provided to form each individually, and then the master glass substrate is divided corresponding to each liquid crystal display panel, and then a plurality of bias voltages by resistance division are applied to the divided individual glass substrates. Liquid crystal driving power supply lines for matrix driving based on the voltage averaging method using is provided on both outer sides of the opposite sides of the rectangular display screen so as to be electrically connected to the display electrode pattern, and In a method of manufacturing a liquid crystal display device, which comprises a liquid crystal display panel, and thereafter a liquid crystal driving power source is arranged on the liquid crystal display panel, the two liquid crystal display panels Of the shape display screen, the adjustment resistance is connected to the liquid crystal drive power supply line that is arranged on the side of the rectangular display screen with the smaller electric resistance between the opposite sides, and the electrical resistance between the opposite sides of the other rectangular display screen is connected. It is characterized in that it includes a resistance adjusting step for balancing with a resistance value.

[0020]

According to the method of manufacturing the liquid crystal display device of these two inventions, the liquid crystal driving power supply lines provided on both outer sides of the opposite sides of the display screen for matrix driving based on the voltage averaging method are provided with two rectangles. In a liquid crystal display panel configured with a display screen composed of a shape display screen, by going through a resistance adjusting step of balancing with an electric resistance value,
That is, in order to reduce or eliminate the electric resistance difference between the rectangular display screens, an adjustment resistor is provided in the liquid crystal drive power supply line of the rectangular display screen having the smaller wiring resistance. The wiring resistance difference generated in the display electrode pattern is complemented by the electric resistance difference between the liquid crystal driving power supply lines, and as a result, the contrast difference between the liquid crystal display panels does not occur.

[0021]

Embodiments of the invention of claim 1 will be described in detail below.
In this embodiment, the scanning glass substrate is a band-shaped ITO.
The display electrodes are arranged, and it is obtained by forming an ITO layer over the entire one main surface of the substrate and then etching. Regarding the other signal glass substrate, an ITO layer, a Cr layer and an Al layer are sequentially laminated over one main surface of the substrate and then etched to form display electrodes of the ITO layer in the display region. At the same time, a connection wiring in which an ITO layer, a Cr layer and an Al layer are laminated is provided in the non-display area. In producing the scanning glass substrate and the signal glass substrate, the same steps as those described with reference to FIGS. 4 to 8 are adopted.

In this embodiment, instead of the conventional circuit diagram shown in FIG. 9, a circuit diagram of the voltage averaging method is shown in FIG. 1, and FIG. 2 shows a printed circuit board provided in a liquid crystal display panel based on this circuit. FIG. 3 shows a liquid crystal display panel which is an essential part, and is further formed by bonding the scanning glass substrate and the signal glass substrate together.

According to the liquid crystal display panel 14 of FIG. 3, the scanning glass substrate 15 and the signal glass substrate 16 including the wiring pattern 7b are bonded together to form a rectangular display screen 18, and the signal glass substrate is further formed. A plurality of driving ICs 17 are arranged around the periphery of 16. In a region other than the display screen 18 of the signal glass substrate 16, a signal side liquid crystal drive power supply line 19 corresponding to SEG-U, a signal side liquid crystal drive power supply line 20 corresponding to SEG-D, and further corresponding to COM. A scan side liquid crystal drive power supply line 21 is formed.

FIG. 1 shows a circuit diagram of a voltage averaging method for driving the liquid crystal display panel 14 of the embodiment. The same parts as those in FIG. 9 are designated by the same reference numerals. As shown in FIG. 1, in order to obtain six bias voltages by resistance division, two selection potentials V0
Between V and V5 are 5 resistors (4 R and 1 (a-
4) By further inserting R) in series, four non-selection potentials V1, V2, V3, and V4 are obtained, and these potentials (V
0, V1, V2, V3, V4, V5) are supplied to the liquid crystal driver as liquid crystal drive voltages. Each of these potentials has the same function as in FIG. Further, the circuit of FIG. 1 is different from the circuit of FIG. 9 in the signal side liquid crystal drive power supply line (SEG-U).
A resistor 22 is provided in the.

In the liquid crystal display panel 14 having the signal glass substrate 16 including the wiring pattern 7b, when the resistor 22 is provided, the signal side liquid crystal drive power source line (SE) is used.
A resistance chip is provided on the wiring which is electrically connected to G-U).
For example, an adjusting resistor is provided in a printed circuit board arranged in parallel with the liquid crystal display panel 14 based on this circuit.

FIG. 2 shows the printed circuit board 23, on which a drive signal is output to the IC chip 24 constituting the operational amplifier 8 shown in the circuit diagram of FIG. 1 and the liquid crystal display panel 14. Therefore, the connector 25 is mounted, and other various electronic components are mounted. Also,
A wiring pattern 26 is also formed on the printed board 23, and a part of the wiring pattern 26, that is, the IC chip 2 is formed.
A resistance chip 27 (for example, 10 to 30Ω) that is an adjustment resistor is provided on the wiring pattern 26 between the connector 4 and the connector 25.

Thus, according to the liquid crystal display panel 14 provided with the printed circuit board 23 having the above-mentioned structure, the wiring resistance difference generated in the display electrode pattern can be corrected by the resistance chip 27, whereby the individual liquid crystal displays are displayed. Panel 14
There is no difference in contrast.

In the above embodiment, the step of dividing the master glass substrate after forming the liquid crystal driving power supply line is performed. However, in the embodiment of the invention of claim 2,
After the master glass substrate is divided, a step of forming the liquid crystal driving power supply line is adopted. However, details of the embodiment in such a case will be omitted.

Further, regarding the embodiment of the above-mentioned claim 1,
For a means for transmitting a driving voltage to the display electrode pattern,
When using a wiring pattern on a glass substrate (COG)
However, in the other claim 2, instead of using the wiring pattern on the glass substrate, TAB or the like is used for the means for transmitting the driving voltage, and the I
A liquid crystal display device equipped with a C chip is exemplified.

Also in the liquid crystal display panel thus obtained, by providing a printed board similar to the printed board 23 having the above structure, the wiring resistance difference generated in the display electrode pattern can be corrected by the same resistance chip. As a result, the contrast difference between individual liquid crystal display panels does not occur.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the scope of the present invention. For example, instead of the resistor chip 27, a surface mount type variable resistor may be used. Alternatively, although the COG type liquid crystal display device is described in the embodiment, the same operational effect can be obtained even in a liquid crystal display device of another type, for example, a liquid crystal display device in which a driving IC is mounted on an FPC as in claim 2. can get.

[0032]

As described above, according to the manufacturing method of the present invention, a transparent conductive film is formed on a master glass substrate by sputter deposition, and the transparent conductive film is etched to form a plurality of liquid crystal display panels. In order to eliminate the resistance difference that occurs in the process of providing a display electrode pattern of a predetermined shape, an adjustment resistor is provided in the liquid crystal drive power supply line with the smaller wiring resistance of the display electrode pattern, which allows each liquid crystal display panel to be adjusted. Among them, the contrast difference complements the electric resistance difference between the liquid crystal driving power source lines, and as a result, a high quality and highly reliable liquid crystal display device capable of obtaining a uniform display can be provided.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an example.

FIG. 2 is a plan view showing a main part of a printed circuit board provided in the liquid crystal display panel of the embodiment.

FIG. 3 is a plan view of a liquid crystal display panel of an example.

FIG. 4 is a plan view of a master glass substrate.

5 is a cross-sectional view taken along the section line AA shown in FIG.

FIG. 6 is an explanatory diagram of sputter deposition.

FIG. 7 is a plan view of a master glass substrate having a wiring pattern.

FIG. 8 is a plan view of a master glass substrate having a wiring pattern.

FIG. 9 is a conventional electric circuit diagram.

[Explanation of symbols]

 1 Master Glass Substrate 2 ITO Layer 3 Sputter Deposition Target 5a, 5b, 7a, 7b Display Wiring Pattern 16 Signal Glass Substrate 19, 20 Signal Side Liquid Crystal Driving Power Supply Line 22 Resistor 23 Printed Circuit Board 27 Resistor Chip

Claims (2)

[Claims] 1. A predetermined number for forming a plurality of liquid crystal display panels in which two rectangular display screens are juxtaposed by forming a transparent conductive film on a master glass substrate by sputtering deposition and etching the transparent conductive film. A liquid crystal driving power supply line for matrix driving based on a voltage averaging method using a plurality of bias voltages by resistance division is provided on both outer sides of opposite sides of the rectangular display screen, while providing a display electrode pattern of a shape. It is provided so as to be electrically connected to the display electrode pattern, and then the master glass substrate is divided corresponding to each liquid crystal display panel, and the individual liquid crystal display panel is configured with the divided individual glass substrates. In the method of manufacturing a liquid crystal display device in which a liquid crystal driving power source is later arranged on the liquid crystal display panel, it is caused by the film thickness unevenness in the display electrode pattern. The uneven resistance value caused by the adjustment resistance is adjusted in the liquid crystal driving power supply line which is arranged in one of the two rectangular display screens of the liquid crystal display panel having a smaller electric resistance value between the opposite sides of the rectangular display screen. And a resistance adjusting step for balancing the electric resistance value between the opposite sides of the other rectangular display screen, the manufacturing method of the liquid crystal display device. 2. A transparent conductive film is formed on a master glass substrate by sputter deposition, and the transparent conductive film is etched to form a plurality of liquid crystal display panels having two rectangular display screens arranged side by side. A shape display electrode pattern is provided, then the master glass substrate is divided corresponding to each liquid crystal display panel, and then the voltage average using multiple bias voltages by resistance division is applied to each divided glass substrate. A liquid crystal driving power supply line for matrix driving based on the chemical conversion method is provided on both sides of opposite sides of the rectangular display screen so as to be electrically connected to the display electrode pattern, thereby forming an individual liquid crystal display panel. However, after that, in the method of manufacturing a liquid crystal display device in which a liquid crystal drive power source is arranged on the liquid crystal display panel, uneven film thickness may occur in the display electrode pattern. The uneven resistance value caused by the adjustment resistance is adjusted in the liquid crystal drive power supply line which is arranged in one of the two rectangular display screens of the liquid crystal display panel having a smaller electric resistance value between the opposite sides of the rectangular display screen. And a resistance adjusting step for balancing the electric resistance value between the opposite sides of the other rectangular display screen, the manufacturing method of the liquid crystal display device.