JPH0830803B2 - Method for manufacturing display electrode substrate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a display electrode substrate used in an active matrix type display device.

2. Description of the Related Art FIG. 12 is a plan view showing an example of a surface structure during a manufacturing process of a display electrode substrate used in a conventional active matrix type color liquid crystal display device. In FIG. 12, a source bus line 1 is a signal line bus line, and a gate bus line 2 is a scanning line bus line. These are arranged on the transparent insulating substrate 7 at right angles to each other via an insulating layer. It is formed by arranging so as to cross over.

Thin film transistor (hereinafter, TFT)
3 is an element serving as a switching element of the display electrode substrate, and the TFT 3, the pixel electrode 4, and an auxiliary capacitance (not shown) are connected to the source bus line 1 and the gate bus line 2
Each of the cells surrounded by and is formed by arranging in a matrix, and the source electrode of the TFT3 is the source bus line 1, the gate electrode is the gate bus line 2, and the drain electrode is the pixel electrode 4 and the auxiliary. Each is connected to one end of the capacitor. A short circuit is provided outside the area where the source bus line 1, gate bus line 2, TFT3, pixel electrode 4, etc. are formed to prevent dielectric breakdown due to external static electricity during the manufacturing process of the display electrode substrate. A ring line 5 is formed, and each of the source bus line 1 and the gate bus line 2 is connected to the short ring line 5.

FIG. 13 is an enlarged vertical sectional view showing a part of an active matrix type color liquid crystal display device assembled using the display electrode substrate 6 described above.

In FIG. 13, the gate electrode 8 of the TFT 3 and the electrode 10 of the auxiliary capacitor 9 are formed on the transparent insulating substrate 7, and the gate insulating film 11 is formed thereon. In addition, the gate insulating film 11
An a-si (i) (intrinsic semiconductor amorphous silicon) layer 12 and an a-si (n ⁺ ) (n-type semiconductor non-quality silicon) layer 13 are formed in a portion corresponding to the upper gate electrode 8. The source electrode 14 and the drain electrode 15 are formed thereon, and the TFT 3 is constituted by this. Next, a part is laminated on the drain electrode 15 to form the pixel electrode 4, and the extension portion 4a thereof is laminated on the electrode 10 via the insulating film 11, and the extension portion 4a constitutes the auxiliary capacitor 9. ing. further,
A protective film 16 is formed over the entire surface and an alignment film 17a is formed on the upper surface thereof.

The counter substrate 18 is arranged so as to face the display electrode substrate 6 thus configured, and the liquid crystal layer 24 is interposed between the display electrode substrate 6 and the counter substrate 18. In the counter substrate 18, a color filter 20 is formed on a portion of the entire surface of the transparent insulating substrate 19 facing the display electrode substrate 6 facing the pixel electrode 4, and a light shielding film 21 is formed on the other portion. The counter electrode 22 is formed on the upper surface thereof, and the alignment film 17b is further formed thereon.

The color filter 20 is formed by a method using a printing technique, a method using a photo process and a dyeing technique, a method using a vacuum deposition technique, or the like. Apart from this, a method of forming a color filter by an electrodeposition method is also well known. In this electrodeposition method, a polyester resin in which a dye is dispersed is dissolved in a solvent such as water to prepare an electrodeposition solution, and the counter substrate 18 and the electrodeposition electrode are immersed in the electrodeposition solution so as to face the counter substrate. A DC voltage is applied between the counter electrode 22 of 18 and the electrodeposition electrode, whereby a dye is deposited on the counter electrode 22 of the counter substrate 18 to form a color filter.

Further, it has been attempted to deposit a dye on the pixel electrode 4 on the display electrode substrate 6 to form a color filter by using the above-mentioned electrodeposition method. That is, in this case, the TFT 3 on the display electrode substrate 6 is turned on, and a voltage is selectively applied to the source bus line 1 to which the picture element electrode 4 to be colored is connected, and the opposite picture element is formed. Elementary electrode 4
A color filter is formed by precipitating a dye on. In this method, a color filter is formed on the counter substrate 18.
Compared with the case where 20 is formed, there is an advantage that the pixel electrode 4 and the color filter are almost not displaced, a fine pattern is relatively easily formed, and the manufacturing cost is low.

However, in the case of the above-described conventional manufacturing method in which the color filter is formed on the picture element electrode 4 of the display electrode substrate 6 by the electrodeposition method, the source bus line 1 and the electrodeposition electrode are connected to the DC power source. In order to connect via the above, it is necessary to apply a silver paste, for example, and since the source bus lines 1 are numerous, the application work is troublesome.
If the peeling of the silver paste performed after electrodeposition is insufficient,
There is a problem that the display electrode substrate 6 is contaminated by the silver paste during the process.

In the manufacturing process of the display electrode substrate 6, the short ring wire 5 is used as described above for the purpose of countermeasures against static electricity.
(Fig. 12) is formed, and the source bus line 1 and the gate bus line 2 are usually connected to the short ring line 5. Therefore, in order to perform the above electrodeposition, all the source bus lines 1 must be connected. Not only must it be disconnected from the short ring line 5, but again after the electrodeposition, the source bus line 1 must be used again as a measure against static electricity in subsequent steps.
Had to be reconnected to the short ring wire 5, and the manufacturing process became very complicated.

Therefore, it is an object of the present invention to provide a method of manufacturing a display electrode substrate, which can form a color filter on a pixel electrode by an electrodeposition method in a simple process.

Means for Solving the Problems The present invention provides a pixel element and a color filter corresponding to a plurality of picture elements of each color of an active matrix type color display device on an insulating substrate, and a switching element connected to each picture element electrode. And a plurality of signal lines for transmitting signals to the pixel electrodes through the switching elements and a plurality of signal lines that extend across the signal lines and turn on the switching elements. And a short ring line having peripheral portions on the insulating substrate that extend in the direction intersecting the signal line and the scanning line, respectively, and further an alignment film is formed on the pixel electrodes. In the manufacturing method of 1., a plurality of common electrodes corresponding to the respective colors and extending in the direction intersecting the signal line are formed on the insulating substrate, and the common electrodes are connected to the common electrodes. A voltage is applied to the short ring line while the plurality of signal lines corresponding to the pole colors are commonly connected, the scanning line is connected to the short ring line, and the common electrode is disconnected from the short ring line. Under the condition that the switching element is turned on by applying a voltage, a voltage is applied to the common electrode for each color, and on the pixel electrode for displaying the color corresponding to the common electrode to which the voltage is applied, A color filter is sequentially formed for each color by an electrodeposition method using an electrodeposition liquid for each color, and after forming the color filter, the alignment film is formed with the common electrode connected to the short ring line. And a method for manufacturing a display electrode substrate.

According to the present invention, since a plurality of signal lines corresponding to the pixel electrodes on which color filters of the same color are to be formed are commonly connected to one common electrode, the one common electrode is selected during electrodeposition. A color filter of the same color is formed on the corresponding plurality of picture element electrodes only by applying a voltage thereto.

Moreover, since the connection between the short ring line and the signal line, which is formed for the purpose of countermeasures against static electricity, etc., may be made via the common electrode, the short ring line and the common electrode may be connected before and after the electrodeposition process. The work of disconnecting and connecting the common electrode to the short ring line prior to forming the alignment film can be performed by far fewer disconnecting and connecting operations than the large number of signal lines in the above-mentioned prior art. The workability is significantly improved.

Example FIG. 1 is a partially enlarged plan view showing the surface structure of the display electrode substrate 30 in the first step of the first embodiment of the method for manufacturing a display electrode substrate of the present invention, and FIG. 3 is a plan view schematically showing the entire surface structure of the display electrode substrate 30. FIG. In these and other drawings, hatching may be shown for convenience of illustration.

In FIGS. 1 and 9, glass, quartz glass,
A short ring line 32 is formed around the transparent insulating substrate 31 made of ceramics or the like for the purpose of preventing static electricity, and the short ring line 32 is also formed on the transparent insulating substrate 31.
One end of a plurality of gate bus lines 33, which are arranged in parallel with each other and form a scanning line, are connected to each other. In addition, the gate bus line 33 is provided on the upper side of the transparent insulating substrate 31.
Three common electrodes 34r, 34g, 34b arranged in parallel to
(Hereinafter, any common electrode is represented by reference numeral 34) is formed,
Both ends of these common electrodes 34 are also connected to the short ring line 32. The materials for the short ring line 32, the gate bus line 33, and the common electrode 34 are Mo, Al, Ti, and ITO.
A metal material such as (indium tin oxide) is used.

FIG. 2 is a partially enlarged plan view showing the surface structure of the display electrode substrate 30 in the second step of this embodiment.
In the second step, as shown in FIG. 2, most of the gate bus line 33 and the common electrode 34 are covered with the gate insulating film 35, and a portion overlapping the common electrode 34 is selectively provided with a plurality of contact through holes. 36 is formed. Further, a semiconductor film is provided at a position corresponding to the gate bus line 33.
37 are arranged in a matrix. This semiconductor film
The reference numeral 37 is one member that constitutes a TFT that serves as a switching element of the display electrode substrate 36, and therefore the TFTs are also arranged and formed in a matrix. Among the through holes 36, the through hole 36 on the common electrode 34r is formed at a position corresponding to the 3m + 1th column (m is an integer) from the left end side of the arrangement of the semiconductor films 37, and the through hole 36 on the common electrode 34g is formed. The semiconductor film 37 is formed at a position corresponding to the 3m + second column of the array, and the through hole 36 on the common electrode 34b is formed at a position corresponding to the 3m + 3rd column of the semiconductor film 37 array.

As the gate insulating film 35, a material such as SiO ₂ , SiN _X , Ta ₂ O ₅ is used. Further, as the semiconductor film 37,
Although materials such as a-Si, cdSe, poly-Si, and Te can be used, a-Si is used here and a-Si doped with phosphorus or the like is used.
It has a two-layer structure of an (n ⁺ ) layer and an a-Si (i) layer in which phosphorus or the like is not injected.

FIG. 3 is a partially enlarged plan view showing the surface structure of the display electrode substrate 30 in the third step of this embodiment.
In this third step, as shown in FIG. 3, a plurality of source bus lines 38 forming signal lines are formed on the gate insulating film 35.
Are arranged in parallel with each other so as to be orthogonal to the gate bus lines 33, and one ends thereof are connected to the corresponding common electrodes 34 via the through holes 36, respectively.
Each of the semiconductor films 37 is located near the intersection of the source bus line 38 and the gate bus line 33. The source electrode of each TFT connected to the source bus line 38, the drain electrode of each TFT, and the drain Picture element electrode connected to the electrode
39 is also formed at this time, whereby each TFT 40 and the pixel electrode 39 corresponding thereto are arranged in a matrix. Source bus line 38, source electrode, drain electrode, pixel electrode 39
As the material of, a metal material such as Mo, Al, Ti, or ITO is used.

Through the above steps, the source bus line 38 connected to the source electrode of the TFT 40 is connected to the short ring line 32 via the common electrode 34, while the gate bus line 33 connected to the gate electrode of the TFT 40 is also shorted. Ring wire
Since it is connected to 32, it is possible to prevent the characteristic deterioration of the TFT 40 caused by static electricity or electrochemical reaction generated during the process.

FIG. 4 is a partially enlarged plan view showing the surface structure of the display electrode substrate 30 in the fourth step of this embodiment.
In the fourth step, the display electrode substrate 30 obtained in the third step is used.
First, a SiN _X film is formed by using the plasma CVD method, and then by using the photolithography method, as shown by hatching in FIG. 4, a short ring line 32, a common electrode 34 and a gate bus line 33. The protective film 41 is formed by patterning the SiN _X film into a shape excluding a part of the pixel electrode 39 and the pixel electrode 39. A contact hole 42 for connecting a source signal input terminal to the source bus line 38 is formed at a position on the source bus line 38 near the array portion of the common electrode 34 in the protective film 41.

Then, the connection portion 43 of each common electrode 34 with the short ring line 32 is cut and separated by the laser as shown in FIG.

FIG. 5 is an explanatory view schematically showing the electrodeposition step which is the fifth step of this embodiment. In this step, a color filter is formed on each pixel electrode 39 of the display electrode substrate 30 obtained in the fourth step. In FIG. 5, the electrodeposition tank 44
Polyester with hydrophilic groups such as carboxyl groups,
Electrodeposition in which an anionic polymer material such as a melamine resin mixture and a dye (here, a green dye of the three primary colors of red, green and blue) are mixed and dissolved or dispersed in a solvent such as an inorganic alkali or an organic amine. Liquid 45 is filled, and this electrodeposition liquid 45
The display electrode substrate 30 and the electrodeposition counter electrode 46 are immersed therein.

The positive electrode side of the DC power supply 47 is connected to the common electrode 34g of the display electrode substrate 30, and the negative electrode side of the DC power supply 47 is connected to the electrodeposition opposing electrode 46, respectively, while the short ring line 32 of the display electrode substrate 30, that is, the gate bus line side. Is connected to the positive electrode side of another DC power source 48, and the negative electrode side of the DC power source 48 is connected to the electrodeposition counter electrode 46.

The TFT40 is turned on when a positive voltage is applied to at least one of the gate and the source or between the gate and the drain.
The T40 is turned on, and the pixel electrodes connected to these TFTs 40 through the respective TFTs 40 (3m + 2nd row TFT40 in this case) corresponding to the source bus line 38 connected to the common electrode 34g. A positive voltage is applied to the counter electrode 46 for electrodeposition at 39.

As a result, the green dye in the electrodeposition liquid 45 moves to the display electrode substrate 30 column together with the anionic polymer and adheres on the positive potential pixel electrode 39, and is connected to the common electrode 34g via the TFT 40. A green color filter is formed on all of the picture element electrodes 39. At this time, the pixel electrodes 39 connected to the other common electrodes 34r, 34b are not colored because they have no positive potential.

Further, since the protective film 41 is formed on the gate bus line 33, the source bus line 38, and the TFT 40, the bus lines 33, 38 and the TFT 40 are not colored, and therefore, they are colored. This will surely prevent the adverse effects such as an increase in the resistance value of the bus line and deterioration of the characteristics of the TFT 40.

After the coloring is completed, the display electrode substrate 30 is pulled out of the electrodeposition liquid 45, washed with water, and then heat-cured to complete the formation of the green color filter.

Next, the display electrode substrate 30 is immersed in a red electrodeposition liquid, that is, an electrodeposition liquid using a red dye as the above-mentioned dye,
The red color filter is formed similarly to the case of forming the green color filter. In this case, the common electrode 34r is selected as the common electrode 34 set to the positive potential. Therefore, at this time, the pixel electrodes 39 (3m + 1 column of pixel electrodes 39) connected to the common electrode 34r via the source bus line 38 and the TFT 40 are colored red. In this case, since the colored layer of the pixel electrode 39 previously colored green becomes an insulator, red is not further colored thereon. After the completion of coloring, washing and heat curing are carried out in the same manner as in the case of forming the green color filter, whereby the red color filter is formed.

Similarly, a blue color filter is formed on the remaining pixel electrodes 39 (3m-row pixel electrodes 39) by applying a positive voltage to the common electrode 34b using a blue electrodeposition liquid.
Although the case where each color filter is formed in the order of green, red, and blue is shown here, the order may be changed according to the properties of the dye material.

FIG. 6 is a partially enlarged plan view showing the surface structure of the display electrode substrate 30 in the fifth step of this embodiment.
In this step, in order to prevent the occurrence of defects such as characteristic deterioration of the TFT 40 due to static electricity or an electrochemical reaction generated in the subsequent steps, as shown by symbol A in FIG.
The separation points of the short ring line 32 of 34 are respectively joined again. In this case, a method such as max deposition by sputtering is used.

FIG. 7 is a partially enlarged plan view showing the surface structure of the display electrode substrate 30 in the seventh step of this embodiment.
In this step, an alignment film is formed on the surface of the display electrode substrate 30 on which the color filter is formed in the sixth step,
The gate bus line 33 and the source bus line 38 are separated from the short ring line 32. The disconnection of the source bus line 38 is carried out by separating each common electrode 34 from the short ring line 32 by a laser or the like as shown by reference numeral B in FIG. At this time, in order to separate the source bus lines 38 from each other, the common electrodes 34 are provided for each portion between the adjacent source bus lines 38, as indicated by a symbol C.
Is also disconnected.

In order to disconnect the source bus line 38 from the short ring line 32 and to disconnect the source bus lines 38 from each other, for example, the portion of the display electrode substrate 30 where the common electrode 34 is formed is indicated by the one-dot chain line in FIG. It may be cut off and removed.

The display electrode substrate 30 thus obtained is assembled into an active matrix type color liquid crystal display device by interposing a liquid crystal layer between these substrates which are arranged to face the counter substrate on which the counter electrode is formed.

FIG. 10 is a partially enlarged plan view showing the surface structure of the display electrode substrate 30 in the intermediate step of the second embodiment of the method for manufacturing a display electrode substrate of the present invention.

As shown in FIG. 10, in this embodiment, three common electrodes are used.
34 are connected to the short ring line 32 via the TFT 49, respectively, and the process of joining / disconnecting the common electrode 34 and the short ring line 32 in the first embodiment is replaced by turning on / off the TFT 49. Its on / off control is TFT4
This is performed by the voltage applied to the gate electrode 49a of 9. In this case, the gate insulating film 35 and the protective film 4 covering the TFT 40 in the screen
1 is patterned so as to extend to the above-mentioned junction cutting TFT 49. Since these TFTs 49 can be formed by the same process as the process of forming the TFT 40 in the screen, the manufacturing process is not particularly complicated.

FIG. 11 is a plan view schematically showing the surface structure of the entire display electrode substrate 30 in the process in the middle of the third embodiment of the method for manufacturing a display electrode substrate of the present invention.

As shown in FIG. 11, in this embodiment, the resistance of the source bus line 37 and the wiring structure do not affect the quality of the coloring and workability in the electrodeposition process and the workability of the display electrode substrate. Three common electrodes 34 are formed on each of the lower sides. In this case, in the electrodeposition step, for example, after first applying a voltage to the common electrode 34 on the upper side to perform the electrodeposition process,
The display electrode substrate 30 is turned upside down and immersed in the electrodeposition liquid, and a voltage is applied to the common electrode 34 located on the lower side to perform electrodeposition treatment, whereby the entire surface of the display electrode substrate 30 is processed. The color filter can be formed uniformly over the entire area.

As described above, according to the method of manufacturing the display electrode substrate of the present invention, a plurality of signal lines corresponding to the pixel electrodes on which the color filters of the same color are to be formed are connected to one common electrode, and the electric current is reduced. Since one of the common electrodes is selected and a voltage is applied to the common electrode at the time of deposition, a color filter can be formed on the pixel electrode by a simple process, and an electrodeposition liquid for each color can be used. When forming the color filter by the deposition method, the common electrode is in a state of being cut off from the short ring line, and after forming this color filter, at the time of forming the alignment film on at least the pixel electrode, measures against static electricity are required. Since the number of common electrodes is much smaller than the number of signal lines in the work of connecting the short ring line and the common electrode to each other for the purpose of the short circuit in the above-mentioned prior art. The work of disconnecting and connecting the ring line and a large number of signal lines is significantly simplified.

[Brief description of drawings]

FIG. 1 is a partially enlarged plan view showing a surface structure of a display electrode substrate in a first step of a method of manufacturing a display electrode substrate which is an embodiment of the first embodiment of the present invention, and FIG. Second
5 is a partially enlarged plan view of the surface structure in the step, FIG. 3 is a partially enlarged plan view of the surface structure in the third step, and FIG. 4 is a partially enlarged plan view of the surface structure in the fourth step.
FIG. 6 is an explanatory view schematically showing the fifth step, FIG. 6 is a partially enlarged plan view of the surface structure in the sixth step, and FIG. 7 is a partially enlarged plan view of the surface structure in the seventh step.
FIG. 9 is a partially enlarged plan view of the surface structure in another aspect of the seventh step, FIG. 9 is a plan view schematically showing the surface structure of the entire display electrode substrate in the first step, and FIG. 10 is a second view of the present invention. FIG. 11 is a plan view showing a partially enlarged surface structure of the display electrode substrate in the intermediate step of the method for manufacturing a display electrode substrate which is the embodiment of the present invention, and FIG. 11 is a display electrode substrate which is the third embodiment of the present invention. FIG. 12 is a partially enlarged plan view showing the surface structure of the display electrode substrate in the middle of the manufacturing method of FIG. 12, and FIG. 12 is a partially enlarged view of the surface structure of the display electrode substrate obtained by the conventional manufacturing method. FIG. 13 is a plan view showing, in an enlarged manner, a part of an active matrix type color liquid crystal display device assembled by using the display electrode substrate. 31 …… Transparent insulating substrate, 32 …… Short ring wire, 33 ……
Gate bus line, 34r, 34g, 34b …… Common electrode, 39 ……
Electrodeposition liquid, 46 …… Counter electrode for electrodeposition, 47,48 …… DC power supply

Claims (1)

[Claims] 1. A pixel array and a color filter corresponding to a plurality of picture elements of each color of an active matrix type color display device, and a switching element connected to each picture element electrode are arranged in a matrix on an insulating substrate. And a plurality of signal lines for transmitting a signal to the pixel electrode through the switching element, a plurality of scanning lines extending crossing the signal line and for turning on the switching element, and insulating. In a method of manufacturing a display electrode substrate, a short ring line having a portion extending in a direction intersecting a signal line and a scanning line is formed in a peripheral portion of the substrate, and an alignment film is formed on a pixel electrode. A plurality of common electrodes corresponding to the respective colors and extending in the direction intersecting the signal line are formed on the substrate, and a plurality of common electrodes corresponding to the colors of the common electrodes are formed on each common electrode. When the signal lines are connected in common, the scanning line is connected to the short ring line, and the common electrode is cut off from the short ring line, a voltage is applied to the short ring line to turn on the switching element. Under the above conditions, a voltage is applied to the common electrode for each color, and the electrodeposition liquid for each color is used on the pixel electrode for displaying the color corresponding to the common electrode to which the voltage is applied. A method of manufacturing a display electrode substrate, wherein a color filter is sequentially formed for each color by an electrodeposition method, and after forming the color filter, an alignment film is formed with a common electrode connected to a short ring line.