KR19990016123A - LCD and its manufacturing method - Google Patents

Abstract

The liquid crystal display device according to the present invention and its manufacturing method are the first to the first through the electrodeposition method on a pixel electrode of a TFT substrate equipped with a thin film transistor and a pixel electrode so as to be connected to a plurality of data lines and a gate line, respectively. Forming a three color filter layer sequentially and sequentially; and forming a transparent electrode on the first to third color filter layers, 1) forming a transparent electrode immediately without a protective layer deposition process. Simplification and cost reduction can be realized. 2) In the case of the polysilicon TFT, the driving waveforms of R, G, and B can be applied to the pixel electrode, so that the electrodeposition liquid is selectively added only to the transparent electrode to which the voltage is applied. It is possible to make it possible to be deposited, so that the first to third color filter layers can be formed without a separate photo mask required in the amorphous silicon TFT. .

Description

LCD and its manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device (hereinafter referred to as LCD) used in a note book PC and the like, and more particularly, to a color on a pixel electrode of a TFT substrate. An LCD having a color filter layer to be expressed and a method of manufacturing the same.

In recent years, new advanced imaging devices such as high definition TVs (hereinafter referred to as HDTVs) have been developed. Instead of CRTs, LCDs, ELDs (vacuum fluorescence displays) and VFDs (plasma) are used instead of CRTs. Research on flat panel displays such as display panels is being actively conducted.

Among them, LCD is a representative technology of flat panel display. It is not only capable of driving thin, low cost, low power consumption, but also good matching with integrated circuit, so that besides the display of lap top computer or pocket computer Its use is rapidly expanding as a vehicle loading and a color TV image.

The LCD having such characteristics has a structure in which a C / F (color filter) substrate, which is an upper substrate, and a TFT substrate, which is a lower substrate, are disposed to face each other, and a liquid crystal having dielectric anisotropy is inserted therebetween, thereby providing a pixel selection address. The LCD is driven by switching a TFT added to hundreds of thousands of pixels through an address line (for example, a data driver circuit and a gate driver circuit) to apply a voltage to the pixel.

In this case, the color filter layer formed on the upper substrate is manufactured by a dyeing method, a pigment dispersion method using a pigment, a printing method, an electrodeposition method, etc. Here, as an example, a conventional color filter manufacturing method using an electrodeposition method directly related to the present invention. Let's look at. The manufacturing method is largely divided into four steps, which will be described with reference to the process purity shown in FIGS. 1 to 4.

As a first step, a plurality of first transparent electrodes 12 on a C / F substrate (eg, a glass substrate) 10 subjected to a CP (cutting, polishing) process using a photolithography process as shown in FIG. 1. ).

As a second step, as shown in FIG. 2, R (red) patterns as first to third color filter layers 14, 16, and 18 on the transparent electrode 12 by electrodeposition. And G (green) pattern and B (blue) pattern are sequentially formed. At this time, the process of forming the first to third color filter layers 14, 16, and 18 using the electrodeposition method proceeds through the following steps (a) to (c).

As a process, first, a photosensitive film is deposited on the entire surface of the substrate 10 including the transparent electrode 12, and then the surface of the transparent electrode 12 of the portion where the first color filter layer 14 is to be formed using a photo mask. The photosensitive film is etched to expose it. Subsequently, the substrate 10 is immersed in an electrodeposition tank containing an electrolyte solvent so that the substrate on which the transparent electrode 12 is formed is connected to the anode electrode plate, and the polymer resin (chargeable soluble resin having charge) and the color pigment to which the charge regulator is added are added. After dissolving (dispersing) in the electrolyte solvent, a voltage is applied to the electrode in the electrodeposition tank to selectively deposit the electrodeposition liquid component only on the transparent electrode 12 whose surface is exposed as the first color filter layer 14. To form an R pattern with optimized red spectral properties.

(b) removing the patterned photoresist and depositing the photoresist over the entire surface of the patterned photoresist, and then exposing the surface of the transparent electrode 12 of the portion where the second color filter layer 16 is to be formed by using a photomask. The photoresist is etched, and the electrodeposition liquid component is selectively deposited only on the transparent electrode 12 whose surface is exposed in the same manner as in the process of (a). As the second color filter layer 16, optimized green spectral characteristics To form a G pattern.

(c) removing the patterned photoresist layer and depositing the photoresist layer on the entire surface of the photoresist layer, and then exposing the surface of the transparent electrode 12 of the portion where the third color filter layer 18 is to be formed by using a photomask. The photoresist was etched, and the electrodeposition liquid component was selectively deposited only on the transparent electrode 12 having the surface exposed in the same manner as in step (a). As a third color filter layer 18, an optimized blue spectral characteristic To form a B pattern.

As a third step, as shown in FIG. 3, a predetermined portion on the substrate including the first to third color filter layers 14, 16 and 18 and the transparent electrode 12 is protected from external impact. In order to improve the smoothness and smoothness, an organic transparent resin (eg, acrylic, polyimide, polyacrylate, polyurethane, etc.) having high surface hardness and excellent light transmittance is formed to a predetermined thickness, and has a temperature of about 200 ° C. The protective layer 20 is formed by heating for about 1 hour in a bake oven.

As a fourth step, in order to apply a voltage for driving the liquid crystal as shown in Figure 4, by forming a second transparent electrode 22 on the protective layer 20 to a thickness of 1500Å or less, the upper substrate Complete the manufacture.

However, in the case of forming the first to third color filter layers 14, 16, and 18 by applying the above-mentioned process, since the etching process using three photo masks is required, the LCD manufacturing process itself is The disadvantage is that it is complex and tricky.

Accordingly, an object of the present invention is to provide an LCD and a method of manufacturing the same by forming a color filter layer expressing color on the pixel electrode of a TFT substrate during LCD manufacturing, thereby simplifying the process.

1 to 4 is a process flowchart showing a color filter manufacturing method of a TFT-LCD according to the prior art,

5 to 7 is a process flowchart showing a color filter manufacturing method of a TFT-LCD according to the present invention.

In order to achieve the above object, in the present invention, a TFT substrate having a TFT and a pixel electrode formed so as to be connected to a plurality of data lines and a gate line, respectively, first to third color filter layers formed on the pixel electrode sequentially and repeatedly; In addition, an LCD including a transparent electrode formed on a surface of the first to third color filter layers is provided.

In order to achieve the above object, in the present invention, the first to third color filter layers are formed on a pixel electrode of a TFT substrate equipped with a TFT and a pixel electrode so as to be connected to a plurality of data lines and a gate line, respectively. There is provided an LCD manufacturing method comprising a step of forming a second iteratively and a step of forming a second transparent electrode on the first to third color filter layers using an electrodeposition method.

In such a process, since the first to third color filter layers are formed on the same substrate (TFT substrate) as the data driving circuit and the gate driving circuit for driving the pixel electrode, the transparent electrode is directly formed without the protective layer deposition process. It is possible to form and to simplify the process. In addition, when the LCD is a polysilicon TFT in which a driving circuit is integrated, it is possible to selectively deposit the electrodeposition liquid component only on the second transparent electrode to which the voltage is applied, so that the first to third colors are not required without a separate photo mask. Filter layer formation becomes possible.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

The present invention simplifies the process by forming a color filter layer expressing color on the pixel electrode of a polysilicon TFT in which a driving circuit capable of selectively applying voltage to a liquid crystal or an amorphous silicon TFT in which the driving circuit is not integrated. As a technology that focuses on making it possible, this will be described as follows by referring to the fourth step with reference to the process purity shown in FIGS. 5 to 7.

As a first step, a thin film transistor T and a pixel electrode 102 made of ITO or SnO ₂ are formed on the TFT substrate 100 so as to be connected to a plurality of data lines and gate lines, respectively, as shown in FIG. 5. do.

As a second step, as illustrated in FIG. 6, first to third color filter layers 104, 106, and 108 are sequentially formed on the pixel electrode 102 by using electrodeposition. . In this case, the first to third color filter layer 104, 106, 108 forming process is represented in two ways depending on whether the TFT is an amorphous silicon or a polysilicon TFT. Same as

First, a case of an amorphous silicon TFT in which a driving circuit is not integrated will be described. In the case of the amorphous silicon TFT, each color filter layer is formed during the formation of the color filter layer using the electrodeposition method, and the respective driving waveforms for R, G, and B electrodeposition cannot be selectively applied on the pixel electrode 102. Since it is necessary to add a mask pattern forming process using a photo mask, the process proceeds somewhat more complicated than in the case of a polysilicon TFT. If this is divided into (a) ~ (c) process described as follows.

In the process (a), a photoresist film (not shown) is deposited on the entire surface of the substrate 10 including the pixel electrode 102 and the TFT (T), and then the photomask is used to form the first color filter layer. The photoresist is etched to expose the surface of the pixel electrode 102. Subsequently, the substrate 100 was connected to the positive electrode plate in the electrodeposition tank containing the electrolyte solvent, and the polymer resin (chargeable soluble resin having charge) and the color pigment to which the charge regulator was added were dissolved (dispersed) in the electrolyte solvent. Thereafter, a voltage is applied to an electrode in the electrodeposition tank to form a first color filter layer (R pattern) 104 having a red spectral characteristic selectively optimized only on the pixel electrode 102 where the surface is exposed. Remove it.

As a process, the photoresist film is deposited on the entire surface of the substrate 100 including the first color filter layer 104, and then the surface of the pixel electrode 102 of the portion where the second color filter layer is to be formed using a photo mask is exposed. The photoresist is etched so as to form a second color filter layer (G pattern) 106 having a selectively optimized green spectral characteristic only on the pixel electrode 102 where the surface is exposed in the same manner as in step (a). After that, the photosensitive film is removed.

(c) As a process, a photoresist film is deposited on the entire surface of the substrate 100 including the first and second color filter layers 104 and 106, and then the pixel of the portion where the third color filter layer is to be formed using a photo mask. The photoresist is etched so that the surface of the electrode 12 is exposed, and a third color filter layer B having a blue spectral characteristic selectively optimized only on the pixel electrode 102 on which the surface is exposed in the same manner as in step (a). Pattern) 108, and then the photoresist film is removed.

Next, a case in which the driving circuit is an integrated polysilicon TFT will be described. In the case of the polysilicon TFT, it is possible to selectively apply a voltage to the liquid crystal, and thus, when forming the color filter layer using the electrodeposition method, it is possible to selectively apply the R, G, and B driving waveforms on the pixel electrode 102, The first to third color filter layers 104, 106, and 108 may be sequentially formed without a mask pattern forming process using a photo mask. If this is divided into (a) ~ (c) process described as follows.

As a process (a), the pixel electrode 102 and the substrate 100 including the TFT (T) are connected to a positive electrode plate in an electrodeposition tank containing an electrolyte solvent, and a polymer resin (chargeable solubility with charge) is added. Resin) and colored pigments are dissolved (dispersed) in the electrolyte solvent, and then an R driving waveform is applied to the electrodes in the electrodeposition tank to selectively optimize only on the pixel electrode 102 of the portion where the first color filter layer is to be formed. A first color filter layer (R pattern) 104 having red spectral characteristics is formed.

(b) a second color filter layer having a green spectral characteristic selectively optimized only on the pixel electrode 102 of the portion where the second color filter layer is to be formed by applying a G driving waveform to the anode electrode plate in the electrodeposition tank ( G pattern) 106 is formed.

(c) a third color filter layer having a blue spectral characteristic selectively optimized only on the pixel electrode 102 of the portion where the third color filter layer is to be formed by applying the B driving waveform to the anode electrode plate in the electrodeposition tank ( B pattern).

As a third step, ITO having a thickness of 400-1600 kPa selectively on the first to third color filter layers 104, 106 and 108 using electrodeposition as shown in FIG. This process is completed by forming the transparent electrode 110 of SnO ₂ ) material.

At this time, the process of the third step is largely proceeded through the following (a) ~ (c) process. (A) process, the substrate 100 with the first to third color filter layers 104, 106, 108 is connected to the anode electrode plate in the electrodeposition bath containing the electrolyte solvent (b) process For example, after the transparent conductive material (electrodeposition liquid) is dispersed in the electrolyte solvent (c), the first, second, and third color filter layers 104 may be simultaneously applied to R, G, and B driving waveforms to the cathode electrode plate. ), 106 and 108 are selectively formed on the transparent electrode (110).

As a result, as shown in the cross-sectional view of FIG. 7, the TFT (T) and the pixel electrode 102 are formed on the TFT substrate 100 so as to be connected to a plurality of data lines and gate lines, respectively, and on the pixel electrode 102. First to third color filter layers 104, 106 and 108 are sequentially formed repeatedly, and transparent electrodes 110 are formed on the first to third color filter layers 104, 106 and 108. The color filter for LCD of this formed structure is manufactured.

As such, when the first to third color filter layers 104, 106, and 108 are formed on the TFT substrate 100, the transparent electrode 110 is formed immediately without forming a protective layer after the color filter layer is formed. In addition, in the case of the polysilicon TFT, the exposure process required for forming the color filter layer using the electrodeposition method can be skipped, thereby simplifying the process. In addition, since both the color filter layer and the data and gate driving circuits are formed on the TFT substrate 100, the video signal is applied to the R, G, and B patterns only with a minimum electrode terminal connection and a driving circuit disposed outside the LCD panel. It becomes possible.

As described above, according to the present invention, since 1) the first to third color filter layers are formed on the pixel electrode on the TFT substrate by electrodeposition, it is possible to form a transparent electrode immediately without the protective layer deposition process, thereby simplifying the process. And cost reduction, and 2) in the case of the polysilicon TFT, the driving waveforms of R, G, and B can be applied to the pixel electrode, so that the electrodeposition liquid component is selectively deposited only on the transparent electrode to which the voltage is applied. The first to third color filter layers can be formed without a separate photo mask required for the amorphous silicon TFT.

Claims (13)

A TFT substrate provided with a thin film transistor and a pixel electrode so as to be connected to a plurality of data lines and a gate line, respectively; First to third color filter layers sequentially formed on the pixel electrode sequentially and repeatedly; And a second transparent electrode formed on a surface of the first to third color filter layers. The liquid crystal display device of claim 1, wherein the pixel electrode and the transparent electrode are made of any one selected from ITO and SnO ₂ . The liquid crystal display device according to claim 1, wherein the transparent electrode has a thickness of 400 to 1600 kW or less. The liquid crystal display device of claim 1, wherein the thin film transistor is formed of any one selected from amorphous silicon and polysilicon thin film transistor. Forming a first to third color filter layers sequentially and repeatedly on the pixel electrode of the TFT substrate provided with the thin film transistor and the pixel electrode so as to be connected to the plurality of data lines and the gate line, respectively; And forming a transparent electrode on the first to third color filter layers. The method of claim 5, wherein the pixel electrode and the transparent electrode are formed of one selected from ITO and SnO ₂ . The method of claim 5, wherein the transparent electrode is formed to a thickness of 400 ~ 1600Å or less. The method of claim 5, wherein the thin film transistor is formed of any one selected from an amorphous silicon thin film transistor and a polysilicon thin film transistor. The process of claim 5, wherein the first to third color filter layers are sequentially formed on the pixel electrode by the electrodeposition method, respectively. Forming a photoresist film on a substrate including the pixel electrode and the thin film transistor so that the surface of the pixel electrode of the portion where the first color filter layer is to be formed is exposed; Optimized red spectral characteristics on the pixel electrode with the surface exposed by connecting the substrate to a positive electrode plate in an electrodeposition bath containing an electrodeposition liquid (an electrolyte solvent in which a polymer resin and a colored pigment are dispersed) and applying a voltage to the electrode Forming a first color filter layer having a, Removing the photosensitive film; Forming a photoresist film on a substrate including the pixel electrode and the thin film transistor so that the surface of the pixel electrode of the portion where the second color filter layer is to be formed is exposed; Optimized green spectral characteristics on the pixel electrode exposed to the surface by connecting the substrate to a positive electrode plate in an electrodeposition bath containing an electrodeposition liquid (an electrolyte solvent in which a polymer resin and a colored pigment are dispersed) and applying a voltage to the electrode Forming a second color filter layer having: Removing the photosensitive film; Forming a photoresist film on a substrate including the pixel electrode and the thin film transistor so that the surface of the pixel electrode of the portion where the third color filter layer is to be formed is exposed; Optimized blue spectral characteristics on the pixel electrode exposed to the surface by connecting the substrate to a positive electrode plate in an electrodeposition bath containing an electrodeposition liquid (an electrolyte solvent in which a polymer resin and a colored pigment are dispersed) and applying a voltage to the electrode Forming a third color filter layer having: A method of manufacturing a liquid crystal display device, comprising the step of removing the photosensitive film. The process of claim 5, wherein the first to third color filter layers are sequentially formed on the pixel electrode by the electrodeposition method, respectively. Connecting a substrate on which a thin film transistor and a pixel electrode are formed to an anode electrode plate in an electrodeposition tank containing an electrodeposition liquid (an electrolyte solvent in which a polymer resin and a coloring pigment are dispersed); Applying a red driving waveform to the anode electrode plate in the electrodeposition tank to form a first color filter layer having a red spectral characteristic selectively optimized only on the pixel electrode of the portion where the first color filter layer is to be formed; Applying a green driving waveform to the anode electrode plate in the electrodeposition tank to form a second color filter layer having a selectively optimized green spectral characteristic only on the pixel electrode of the portion where the second color filter layer is to be formed; Applying a blue driving waveform to the anode electrode plate in the electrodeposition tank to form a third color filter layer having a blue spectral characteristic selectively optimized only on the pixel electrode of the portion where the third color filter layer is to be formed. Liquid crystal display device manufacturing method. The method of claim 5, wherein the transparent electrode is formed by electrodeposition. 12. The method of claim 11, wherein the transparent electrode is a step of connecting the substrate on which the first to third color filter layers are formed on the anode electrode plate in the electrodeposition tank containing the electrodeposition liquid (the electrolyte solvent in which the transparent conductive material is dispersed), and the electrodeposition tank. A method of manufacturing a liquid crystal display device, comprising the step of forming a transparent electrode by applying a voltage to an anode electrode plate therein. The method of claim 12, wherein the red, green, and blue driving waveforms are simultaneously applied to the anode electrode plate.