KR20040047392A - Transflective type liquid crystal display panel and method of manufacturing the same - Google Patents

Abstract

PURPOSE: A semi-reflective LCD(Liquid Crystal Display) panel and a manufacturing method thereof are provided to enhance the efficiency of reflection since a microlens with a complete shape can be also obtained at the boundary portion between a reflective region and a transmittance region due to the transmittance window of a polygonal closed curve shape. CONSTITUTION: A transparent electrode(300) is formed on an organic insulation film having a protrusion/depression structure. A reflective electrode(320) is formed on the transparent electrode(300) and has a transmittance window(310) for making the transparent electrode(300) expose as a polygonal closed curve shape. The reflective electrode(320) is divided by the first region members(340) and the second region members(350) which are formed within a boundary line(330) of a pixel with a relative high and low. The second region members(350) is surrounded by the first region members(340) as a closed curve shape.

Description

Semi-transmissive liquid crystal display panel and a method of manufacturing the same {TRANSFLECTIVE TYPE LIQUID CRYSTAL DISPLAY PANEL AND METHOD OF MANUFACTURING THE SAME}

The present invention relates to a transflective liquid crystal display device, and more particularly, to a transflective liquid crystal display panel for improving reflection efficiency and a method of manufacturing the same.

In today's information society, the role of electronic display devices becomes more and more important, and various electronic display devices are widely used in various industrial fields. In the electronic display field, new functions of electronic display devices that are suitable for the demands of the information society, which are being developed and diversified, are continuously being developed.

In general, an electronic display device refers to a device that transmits various information to a human through vision. In other words, an electronic display device may be defined as an electronic device that converts electrical information signals output from various electronic devices into optical information signals recognizable to a human's view, and has a role of bridging a bridge between humans and electronic devices. It can be defined as.

In such an electronic display device, when an optical information signal is displayed by a light emitting phenomenon, it is called an emissive display device, and when a light information signal is displayed by light modulation due to reflection, scattering, interference, etc. It is called a non-emissive display device. The light emitting display device, also called an active display device, includes a cathode ray tube (CRT), a plasma display panel (PDP), a light emitting diode (LED), and an electroluminescent display (elector luminescent). display; ELD). The light receiving display device may include a liquid crystal display (LCD), an electrophoretic image display (EPID), and the like.

Cathode ray tube (CRT), the oldest display device used in image display devices such as televisions and computer monitors, occupies the highest share in terms of display quality and economy, but heavy weight, large volume and placed consumption. It has many disadvantages such as power.

However, due to rapid advances in semiconductor technology, electronic display devices suitable for a new environment, that is, thin and light, low driving voltage and low power consumption, according to the miniaturization and low voltage and low power of various electronic devices, and small and light electronic devices There is an increasing demand for a flat panel display device having the characteristics of.

Among the various flat panel display devices currently developed, liquid crystal displays are thinner and lighter than other display devices, and are widely used in various electronic devices because they have low power consumption and low driving voltage and can display images close to cathode ray tubes. have. In addition, since the liquid crystal display device is easy to manufacture, its application range is further expanded.

The liquid crystal display device is a transmissive liquid crystal display device that displays an image using a backlight positioned on the back of the liquid crystal cell depending on the light source, a reflective liquid crystal display device using external natural light, and displays in a dark place where no indoor or external light source exists The device is classified into a transflective liquid crystal display device which operates in a transmissive display mode for displaying using the internal light source of the device itself and in a reflective display mode for reflecting and displaying external incident light in an outdoor high-illuminance environment.

Among the liquid crystal display devices currently used, an electrode is formed on each of two substrates, and a device having a thin film transistor (TFT) for switching a voltage applied to each electrode.

1 is a cross-sectional view of a transflective liquid crystal display device according to the related art having a thin film transistor, and illustrates an amorphous silicon thin film transistor-liquid crystal display device having a bottom-gate structure.

Referring to FIG. 1, a conventional transflective liquid crystal display device includes a first substrate 100, a second substrate 200 disposed to face the first substrate 100, and a liquid crystal layer 255 formed between the substrates. And a backlight assembly (not shown) disposed at the rear of the liquid crystal cell.

The first substrate 100 may include a first insulating substrate 110, a thin film transistor 120 formed on the first insulating substrate 110, and a contact hole 140 exposing a portion of the thin film transistor 120. The organic insulating layer 150, the transparent electrode 160, and the reflective electrode 170 are formed.

The thin film transistor 120 includes a gate electrode 122, a gate insulating layer 124, an active pattern 126, an ohmic contact pattern 128, a source electrode 130, and a drain electrode 132. The transparent electrode 160 is formed of a backlight and transmits light incident through the first substrate 100, and at the same time, the pixel electrode connected to the thin film transistor 120 formed in one pixel area of the first substrate 100. Play a role. The reflective electrode 170 reflects light incident through the second substrate 200 and simultaneously serves as a pixel electrode. That is, the region where only the transparent electrode 160 exists is provided to the transmission window 180, and other portions thereof are provided to the reflection window reflecting external light incident through the second substrate 200.

Here, in order to increase the amount of reflection of light reflected by the reflective electrode 170 and to improve the viewing angle, a plurality of uneven surfaces 190 are formed on the surface of the organic insulating layer 150. In addition, since the transparent electrode 160 and the reflective electrode 170 have a uniform thickness on the organic insulating layer 150, the transparent electrode 160 and the reflective electrode 170 have the same surface structure as the organic insulating layer 150.

The second substrate 200 is formed of the second insulating substrate 210, the color filter layer 220 and the transparent common electrode 230 formed of the RGB pixels formed on the second insulating substrate 210 and expresses a predetermined color as light passes. ).

In addition, according to the alignment direction of the liquid crystal layer 255, the first polarizing plate 240 and the second polarizing plate 240 to make the external light transmission direction constant on the outer surfaces of each of the first substrate 100 and the second substrate 200 ( 250) is attached. In this case, the first polarizing plate 240 and the second polarizing plate 250 are linear polarizers installed such that the polarization axes are perpendicular to each other.

FIG. 2 is a plan view illustrating the first substrate of FIG. 1.

As illustrated in FIG. 2, the first substrate 100 of the liquid crystal display according to the related art is divided into a reflection area 260 and a transmission area 270. Here, the reflective region 260 is a region where the reflective electrode 170 is present, and the transparent region 270 is a quadrangle (or rectangle) and is formed by the transmission window 180 formed by removing the reflective electrode 170. 160) is an area where only there exists.

The reflective electrode 170 is formed on the organic insulating layer 150 having a plurality of irregularities, and is divided into concave portions 280 and convex portions 290 that are formed at a relatively high level in the boundary line 220 of the pixel. The recesses 280 have a relatively lower height than the convex portions 290, the convex portions 290 have a relatively higher height than the concave portions 280, and the recesses 280 define the convex portions 290. It is formed to surround the closed curve, the convex portions 290 function as a micro lens.

As described above, the transparent window 180 is formed by removing the reflective electrode 170 in a square (or rectangular) shape as shown in FIG. 2 without considering the protective film having the uneven structure when forming the transparent window.

Therefore, as in the case of 'A' which is a boundary portion between the reflective region and the transmissive region, part of the convex portions functioning as the microlens is removed, which causes a problem in that the reflection efficiency of the liquid crystal display device is lowered.

Accordingly, an object of the present invention is to provide a semi-transmissive liquid crystal display panel and a method for manufacturing the same, which can improve reflection efficiency.

Another object of the present invention is to provide a transflective liquid crystal display device having the transflective liquid crystal display panel.

1 is a cross-sectional view of a transflective liquid crystal display device according to the prior art.

FIG. 2 is a plan view illustrating the first substrate of FIG. 1.

3 is a plan view showing a TFT substrate having a reflective electrode according to the present invention.

4A to 4G are diagrams illustrating in detail a manufacturing process of the TFT substrate illustrated in FIG. 3.

5 is a plan view of a second mask pattern.

* Description of the symbols for the main parts of the drawings *

300: transparent electrode 310: transmission window

320: reflective electrode 340: first region portions

350: second region portions

According to an aspect of the present invention, a transflective liquid crystal display panel includes a substrate; A protective film laminated to have a concave-convex pattern having first and second region portions on the substrate; A transparent electrode laminated on the organic insulating layer with a uniform thickness; In order to open a predetermined portion of the transparent electrode, and having a transmission window in the form of a polygonal closed curve corresponding to the concave-convex pattern, characterized in that it comprises a reflective electrode stacked on the transparent electrode.

In addition, a semi-transmissive liquid crystal display panel manufacturing method according to another feature for achieving the object of the present invention comprises the steps of forming a pixel on the substrate; Forming an organic insulating layer having an uneven pattern including first and second region portions on the substrate on which the pixel is formed; Forming a transparent electrode with a uniform thickness on the organic insulating film; Forming a reflective electrode layer with a uniform thickness on the transparent electrode: removing a predetermined portion of the reflective electrode layer by a mask pattern having an opening in the form of a polygonal closed curve corresponding to an uneven pattern including the first region portions and the second region portions Forming a reflective electrode characterized in that it comprises.

Here, the first region portions have a groove shape having a low height relative to the second region portions, and the second region portions have a protrusion shape having a high height relative to the first region portions.

According to another aspect of the present invention, a transflective liquid crystal display device includes a first substrate on which pixels are formed, a second substrate formed to face the first substrate, and a liquid crystal layer formed between the first substrate and the second substrate. Liquid crystal cell comprising a; A protective film and a transparent electrode sequentially stacked on the first substrate so as to have an uneven pattern formed by the first region portions and the second region portions; In order to open a predetermined portion of the transparent electrode, and having a transmission window in the form of a polygonal closed curve corresponding to the concave-convex pattern, characterized in that it comprises a reflective electrode stacked on the transparent electrode.

Hereinafter, a transflective liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a plan view showing a TFT substrate having a reflective electrode according to the present invention.

Referring to FIG. 3, a TFT substrate according to the present invention is formed on a transparent electrode 300 and a transparent electrode 300 formed on an organic insulating layer (not shown) having an uneven structure thereon, and has a polygonal closed curve shape. And a reflective electrode 320 having a transmission window 310 exposing the transparent electrode 300.

Here, the reflective electrode 320 is divided into first region portions 340 and second region portions 350 that are formed at a relatively high level in the boundary line 330 of the pixel, and the first region portions 340 are formed in the second region. The region portions 350 are formed to enclose a closed curve. The first region portions 340 are formed to have a groove shape having a relatively lower height than the second region portions 350, and the second region portions 350 are formed to have a shape of a protrusion having a relatively high height. It functions as a micro lens.

In addition, the transmission window 310 corresponds to a structure of the first area portions 340 and the second area portions 350 to form a line located between the first area portions 340 and the second area portions 350. Accordingly, a predetermined portion of the reflective electrode 320 is removed and formed. Here, an area where the transparent electrode 300 is exposed by the transmission window 310 is a transmission area, and an area where the reflection electrode 320 is present is a reflection area.

The transmission area is an area for displaying an image by the transparent electrode 300 that transmits light generated from a backlight (not shown) formed on the rear surface of the TFT substrate, and the reflection area is a reflection electrode for reflecting light incident from the outside ( 320 is an area for displaying an image.

As described above, the transmission window 310 is formed along a line positioned between the first area portions 340 and the second area portions 350 to form a second at the boundary portion B between the transmission area and the reflection area. The region portions 350 have a complete structure. Therefore, the microlens of a complete form is formed also in the boundary part of a transmission area and a reflection area.

Hereinafter, a process of manufacturing a liquid crystal display device having a TFT substrate shown in FIG. 3 will be described in detail with reference to the drawings.

4A to 4G are views illustrating a manufacturing process of the TFT substrate illustrated in FIG. 3 in detail, and FIG. 5 is a plan view illustrating a second mask pattern.

Referring to FIG. 4A, a first metal film (not shown) made of aluminum (Al), chromium (Cr), or molybdenum tungsten (MoW) may be formed on a first substrate 400 made of an insulating material such as glass or ceramic. After the deposition by the sputtering method, the first metal film is patterned to form a gate electrode 411.

Subsequently, silicon nitride is deposited on the entire surface of the first substrate 400 on which the gate electrode 411 is formed by plasma-enhanced chemical vapor deposition (hereinafter referred to as PECVD) to form a gate insulating film 412. Form.

As an active layer (not shown) on the gate insulating film 412, for example, an amorphous silicon film is deposited by a PECVD method, and as an ohmic contact layer (not shown), for example, n ⁺ doped An amorphous silicon film is deposited by the PECVD method. At this time, the amorphous silicon film and the n ⁺ doped amorphous silicon film are deposited in-situ in the same chamber of the PECVD facility. Subsequently, the ohmic contact layer and the active layer are sequentially patterned to form an active pattern 413 consisting of an amorphous silicon film on the gate insulating film 412 on the gate electrode 411 and an ohmic contact layer pattern consisting of an n ⁺ doped amorphous silicon film. 414 is formed.

After depositing a second metal film (not shown) such as chromium (Cr) on the entire surface of the resultant by a sputtering method, the second metal film is patterned to form a source electrode 415 and a drain electrode 416. Subsequently, the exposed ohmic contact layer pattern 414 between the source electrode 415 and the drain electrode 416 is removed by a reactive ion etching (RIE) method.

As a result, the TFT 410 including the gate electrode 411, the active pattern 413, the ohmic contact layer pattern 414, the source electrode 415, and the drain electrode 416 is formed on the first substrate 400. .

Referring to FIG. 4B, a photosensitive organic insulating layer 420 such as an acrylic resin is coated on the entire surface of the first substrate 400 on which the TFT 410 is formed by a spin-coating method or a slit-coating method. Since the organic insulating layer 420 suppresses the generation of parasitic capacitance between the data wirings due to the low dielectric constant, the pixel electrode may be formed to overlap the gate line and the data line, thereby implementing a liquid crystal display having a high aperture ratio. .

Referring to FIG. 4C, a first mask 430 having a predetermined pattern is formed on the organic insulating layer 420. In this case, the first mask 430 includes an exposure area A and a drain in which the first openings 432 corresponding to the first area portions 340 are formed in order to form irregularities of a predetermined pattern on the organic insulating layer 420. The contact hole forming region B has a second opening 434 for exposing a portion of the electrode 416.

Subsequently, the organic insulating layer 420 is exposed and then developed using a tetramethyl-ammonium hydroxide (TMAH) developer. Then, the uneven pattern 422 is formed while the exposed region is removed in the organic insulating layer 420, and the contact hole 424 is formed in the contact hole forming region to expose the drain electrode 416.

Referring to FIG. 4D, the organic insulating layer 420 is hard-baked for the purpose of reflow, outgassing, and solvent removal. Thereafter, curing is performed at a temperature of about 200 ° C. or more for at least 1 hour to cure and stabilize the organic insulating layer 420. At this time, the curing step is performed to further enhance the hard-baking effect.

At this time, the hard-baking process and the curing process in the furnace or oven 440 are performed at 200 ° C. for at least 1 hour, respectively, so that the uneven pattern 422 may be reflowed through the reflow of the organic insulating layer 420. Adjust the tilt That is, the uneven pattern 422 of the organic insulating layer 420 includes a concave portion 422a having a relatively low height and a convex portion 422b having a relatively high height.

Referring to FIG. 4E, a transparent conductive film such as ITO or IZO is deposited on the organic insulating layer 420 and the contact hole 424 to a uniform thickness to form a transparent electrode 450. The transparent electrode 450 is connected to the drain electrode 416 of the TFT 410 through the contact hole 424. In this case, since the transparent electrode 450 is stacked on the organic insulating layer 420 with a uniform thickness, the transparent electrode 450 has the same surface structure as the organic insulating layer 420.

Referring to FIG. 4F, a reflective electrode layer 460 is formed on the transparent electrode 450 by depositing a metal layer having a high reflectance such as aluminum with a uniform thickness. Subsequently, referring to FIG. 4G, a second mask 470 having a predetermined pattern is formed in the transmissive region on the reflective electrode layer 460.

As illustrated in FIG. 5, the second mask has an opening 472 in the form of a polygonal closed curve corresponding to the uneven pattern 422 of the organic insulating layer 420 and the transparent electrode 450.

That is, the second mask 470 is an opening for removing a predetermined portion of the reflective electrode layer 460 along a line between the first region portions 340 and the second region portions 350 connected to each other in FIG. 3. Has 470.

Subsequently, when the reflective electrode layer 460 is exposed and developed using a developing solution, the transparent electrode 450 is formed to expose the transparent electrode 450 while the reflective electrode layer 460 is removed from the portion corresponding to the transparent region. Reflective electrode 490 is formed. This completes the TFT substrate.

In the TFT substrate completed through such a manufacturing process, since the transmission window 480 is formed in the shape of a polygonal closed curve, the second region portions 350 serving as the microlenses are completely completed at the boundary portion B between the transmission region and the reflection region. Take form. At this time, since the second region portions 350 have a perfect shape at the boundary portion between the transmission region and the reflection region, the TFT substrate has the same step at the boundary portion between the transmission region and the reflection region.

Although the present invention has been described with an example of configuring the transmission window in the form of a polygonal closed curve, it is obvious that the transmission window can be configured in a curved shape.

As described above, the present invention configures a transmission window having a polygonal closed curve in consideration of the uneven pattern of the organic insulating layer and the transparent electrode.

Therefore, the present invention can obtain a micro lens of a complete form even at the boundary between the reflection area and the transmission area by the transmission window of the polygonal closed curve shape, and the reflection efficiency is improved.

In addition, the present invention can obtain a micro lens of a complete form at the boundary portion between the reflection region and the transmission region, there is an effect that can minimize the light leakage afterimage phenomenon that may occur due to the step.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (10)

Board; A protective film stacked on the substrate to have an uneven pattern including first and second region portions; A transparent electrode laminated on the protective film with a uniform thickness; And a reflective electrode stacked on the transparent electrode, the transmissive window having a polygonal closed curve shape corresponding to the uneven pattern to open a predetermined portion of the transparent electrode. The transflective liquid crystal display panel of claim 1, wherein the passivation layer is an organic insulating material. The transflective liquid crystal display panel of claim 1, wherein the first region portions are connected to each other, and the first region portions surround the second region portions in a closed curve shape. The method of claim 1, wherein the first region portions have a groove shape having a low height with respect to the second region portions, and the second region portions have a protrusion shape having a high height with respect to the first region portions. Transflective liquid crystal display panel. The transflective liquid crystal display panel of claim 1, wherein the transmission window is formed along a line positioned between the first region portions and the second region portions. A liquid crystal cell comprising a first substrate on which pixels are formed, a second substrate facing the first substrate, and a liquid crystal layer formed between the first substrate and the second substrate; A protective film and a transparent electrode sequentially stacked on the first substrate so as to have a concave-convex pattern formed by first and second region portions; And a reflective electrode stacked on the transparent electrode, the transmission window having a polygonal closed curve shape corresponding to the uneven pattern to open a predetermined portion of the transparent electrode. The method of claim 6, wherein the first region portions have a groove shape having a low height with respect to the second region portions, and the second region portions have a protrusion shape having a high height with respect to the first region portions. Transflective liquid crystal display device. The transflective liquid crystal display of claim 6, wherein the transmission window is formed along a line positioned between the first region portions and the second region portions. Forming a pixel on the substrate; Forming an organic insulating layer having an uneven pattern including first and second region portions on the substrate on which the pixel is formed; Forming a transparent electrode with a uniform thickness on the organic insulating film; Forming a reflective electrode layer with a uniform thickness on the transparent electrode: Forming a reflective electrode by removing a predetermined portion of the reflective electrode layer by a mask pattern having an opening having a polygonal closed curve shape corresponding to an uneven pattern including the first region portions and the second region portions. The manufacturing method of the transflective liquid crystal display panel made into. The method of claim 9, wherein the reflective electrode has a transmission window in which a predetermined portion of the reflective electrode layer is removed along a line positioned between the first region portions and the second region portions by an opening of the mask pattern. The manufacturing method of the transflective liquid crystal display panel made into.