KR20070111199A - Diode substrate of transflective type and method for fabricating the same - Google Patents

Abstract

A transflective diode substrate and a manufacturing method thereof are provided to simplify a substrate structure or a manufacturing process of a transflective LCD by using a two-terminal type diode instead of a three-terminal type TFT(Thin Film Transistor) as a switching device. A pixel electrode(116) is formed on a substrate. An insulating pattern is formed on the substrate. Scan lines(114a,114b) are formed on the insulating pattern. A diode is connected to the pixel electrode and the scan line. An organic material pattern(138) covers a reflective area of the scan line, the diode and the pixel electrode. A reflection electrode(142) is overlapped with the organic material pattern.

Description

Semi-transmissive diode substrate and its manufacturing method {Diode Substrate of Transflective Type And Method for Fabricating The Same}

1 is a view schematically showing a transflective liquid crystal display panel according to the present invention.

FIG. 2 is a plan view illustrating a diode substrate of the transflective liquid crystal display panel shown in FIG. 1. FIG.

3 is a cross-sectional view of the transflective diode substrate shown in FIG. 2 taken along lines II ′ and II ′.

4A and 4B are a plan view and a sectional view for explaining a first mask process in the method of manufacturing a transflective diode substrate according to the present invention;

5A and 5B are a plan view and a cross-sectional view for explaining a second mask process in the method of manufacturing a transflective diode substrate according to the present invention.

6A and 6B are cross-sectional views illustrating in detail a second mask process according to the present invention.

7A and 7B are a plan view and a sectional view for explaining a third mask process in the method of manufacturing a transflective diode substrate according to the present invention;

8A and 8B are cross-sectional views illustrating in detail a third mask process according to the present invention.

9A and 9B are a plan view and a cross-sectional view for explaining a fourth mask process in the method of manufacturing a transflective diode substrate according to the present invention;

10A and 10B are cross-sectional views illustrating in detail a fourth mask process according to the present invention.

<Explanation of symbols for the main parts of the drawings>

112: lower substrate 114a, 114b: scan line

130: insulating film 138: organic film

142: reflective electrode 116: pixel electrode

152: transmission hole 132a, 132b: first electrode

134a, 134b: second electrode D1, D2: diode

144a and 144b: scan pad 146: scan pad electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a semi-transmissive diode substrate and a method of manufacturing the same, which can simplify the manufacturing process by using a diode as a switching element.

Liquid crystal displays are roughly classified into a transmission type for displaying an image using light incident from a backlight unit and a reflection type for displaying an image by reflecting external light such as natural light. The transmissive type has a high power consumption of the backlight unit, and the reflective type has a problem in that an image cannot be displayed in a dark environment because it depends on external light.

In order to solve this problem, a transflective liquid crystal display device capable of selecting a transmission mode using a backlight unit and a reflection mode using external light has been developed. Since the transflective liquid crystal display operates in a reflective mode when sufficient external light is sufficient, and in a transmissive mode using a backlight unit when insufficient external light, power consumption can be reduced compared to the transmissive type, and unlike the reflective type, it is not subject to external light constraints.

In general, a semi-transmissive liquid crystal panel includes a color filter substrate and a thin film transistor substrate bonded to each other with a liquid crystal layer interposed therebetween, and a backlight unit disposed behind the thin film transistor substrate. Each pixel of the transflective liquid crystal panel is divided into a reflection region in which a reflection electrode is formed and a transmission region in which the reflection electrode is not formed.

In such a semi-transmissive liquid crystal panel, the thin film transistor substrate includes a semiconductor process and requires a plurality of mask processes, and thus, the manufacturing process is complicated, thereby increasing the manufacturing cost of the liquid crystal panel.

Accordingly, an object of the present invention is to provide a semi-transmissive diode substrate and a method for manufacturing the same, which can simplify the manufacturing process by using a diode as a switching element.

In order to achieve the above object, the transflective diode substrate according to the present invention includes a pixel electrode formed on the substrate; An insulation pattern formed on the substrate; Scan lines formed on the insulating patterns; A diode connected to the pixel electrode and the scan line; An organic material pattern covering reflective regions of the scan line, the diode, and the pixel electrode; A reflective electrode overlapping the organic material pattern is provided.

The diode may include a first electrode connected to the pixel electrode; And a second electrode overlapping the first electrode with the insulating pattern interposed therebetween and connected to the scan line.

The scan line comprises a first scan line adjacent to a first side of the pixel electrode; And a second scan line adjacent to a second side of the pixel electrode, wherein the diode includes a first diode connected with the first scan line and a second diode connected with the second scan line.

The scan pad may further include a scan pad connected to the scan line, and the scan pad may include a scan pad electrode connected to the scan line and the insulating pattern overlapping a lower portion of the scan pad electrode.

The method for manufacturing a transflective diode substrate according to the present invention includes forming a pixel electrode and a first electrode connected to the pixel electrode on the substrate using a first mask; A second pattern overlapping the insulating pattern on the substrate and the first electrode, the scan line overlapping the insulating pattern, and the first electrode and the insulating pattern interposed therebetween by using a second mask; Forming a diode comprising an electrode; Forming an organic material pattern covering a reflection area of the scan line, the diode, and the pixel electrode by using a third mask; Forming a reflective electrode overlapping the organic material pattern using a fourth mask.

The scan line comprises a first scan line adjacent to a first side of the pixel electrode; And a second scan line adjacent to the second side of the pixel electrode.

The forming of the scan line and the second electrode using the second mask may include forming a scan pad electrode connected to the scan line simultaneously with the scan line and the second electrode.

Using the second mask may further form the insulating pattern having the same pattern as the scan pad electrode.

Other objects and advantages of the present invention in addition to the above object will be apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 1 to 10B.

Referring to FIG. 1, the transflective liquid crystal panel according to the present invention includes a color filter substrate 110 and a diode substrate 120 bonded to each other with a liquid crystal 124 interposed therebetween. Each pixel of the transflective liquid crystal panel is divided into a reflection region in which the reflection electrode 142 is formed and a transmission region in which the reflection electrode 142 is not formed.

The color filter substrate 110 has a black matrix 104, a color filter 106 and data lines 108 formed on the upper substrate 102. The black matrix 104 is formed in a matrix form on the upper substrate 102. The black matrix 104 divides an area of the upper substrate 102 into a plurality of cell areas in which the color filter 106 is to be formed, and prevents light interference and external light reflection between adjacent cells. The color filter 106 is formed to be divided into red (R), green (G), and blue (B) in the cell region divided by the black matrix 104, and thus red (R), green (G), and blue (B). Each color transmits light. The data line 108 forms an electric field facing the pixel electrode 116 when the liquid crystal 124 is driven.

The diode substrate 120 is formed in the scan lines 114a and 114b on the lower substrate 112, the diodes D1 and D2 and the pixel electrodes 116 formed in each pixel cell region, and the reflective regions of the pixel cells, and the pixels are formed on the lower substrate 112. A reflective electrode 142 overlapping with the electrode 116 is provided.

FIG. 2 is a plan view illustrating a transflective diode substrate according to an exemplary embodiment of the present invention shown in FIG. 1, and FIG. 3 illustrates lines I-I 'and II-II' of the transflective diode substrate illustrated in FIG. It is sectional drawing cut along the figure.

As described above with reference to FIG. 2, the semi-transmissive diode substrate according to the present invention shown in FIGS. 2 and 3 includes the pixel electrode 116, the scan lines 114a and 114b, the reflective electrode 142, and the diode D1. And D2), and further include scan pads 144a and 144b connected to the scan lines 114a and 114b. In the transflective diode substrate, each pixel cell region is divided into a reflection region in which the reflection electrode 142 is formed and a transmission region in which the reflection electrode 142 is not formed.

The pixel electrode 116 is formed on the lower substrate 112 and is connected to the diodes D1 and D2 through the first electrodes 132a and 132b extending from the pixel electrode 116. The pixel electrode 116 generates a potential difference with the data line of the color filter substrate. Due to the potential difference, the liquid crystal having dielectric anisotropy rotates to adjust the transmittance of the light passing through the liquid crystal layer of each of the reflection region and the transmission region, so that the luminance varies according to the video signal.

The reflective electrode 142 is formed in the reflective region of each pixel cell to reflect external light. Since the reflective electrode 142 has an embossed shape along the shape of the organic material pattern 138 thereunder, the embossed shape scatters external light, thereby increasing reflection efficiency.

In this case, the transmission hole 152 penetrating the organic material pattern 138 is formed in the transmission region so that the length of the optical path through the liquid crystal layer is the same in the reflection region and the transmission region. Accordingly, the length of the optical path through which the transmitted light TL passing through the transmission area passes through the liquid crystal layer and the length of the optical path through the liquid crystal layer become equal to the length of the reflected light RL passing through the reflective area. The transmission efficiency of the transmission mode becomes equal.

The scan lines 114a and 114b are connected to a driver (not shown) through the scan pads 144a and 144b. In addition, the insulating pattern 130 directly overlaps the scan lines 114a and 114b. In addition, the scan lines 114a and 114b are connected to the diodes D1 and D2 through the second electrodes 134a and 134b extending from the scan lines 114a and 114b.

The scan pads 144a and 144b include a scan pad electrode 146 extending from the scan lines 114a and 114b and an insulating pattern 130 superimposed under the scan pad electrode 146.

The scan lines 114a and 114b described above may be formed as one line. In addition, the scan lines 114a and 114b are adjacent to the first side of the pixel electrode 116 as shown in the figure to form dual first and second diodes D1 and D2 for each pixel cell. It may be formed as a double line including one scan line 114a and a second scan line 114b adjacent to the second side of the pixel electrode 116.

The diodes D1 and D2 are connected to the first electrodes 132a and 132b connected to the pixel electrode 116 and the scan lines 114a and 114b, and have the insulating pattern 130 interposed therebetween. 132b and second electrodes 134a and 134b overlapping each other. As a result, the diodes D1 and D2 adopt a sandwich structure of a conductor / insulator / conductor and thus have diode switching characteristics. Such diodes D1 and D2 are turned on when a voltage equal to or greater than a threshold voltage is applied through the scan lines 114a and 114b to apply a voltage to the corresponding pixel. When the diodes D1 and D2 of the pixel are turned off after the voltage is applied, the voltage applied to the pixel is applied to the pixel electrode 116 and the pixel electrode 116 until the next driving voltage is applied. ) Is filled in the liquid crystal cell (clc) composed of data lines opposed to each other with the liquid crystal layer interposed therebetween.

The diodes D1 and D2 used as the switching elements may be formed of a first diode D1 and a second diode D2 symmetrically connected to the first and second scan lines 114a and 114b. have. The first diode D1 and the second diode D2 receive a signal having polarities opposite to each other through the first and second scan lines 114a and 114b to drive the pixel. Diodes have asymmetrical characteristics in which the voltage varies depending on the polarity. However, as the dual diodes D1 and D2 receiving opposite polarity signals are connected to one pixel, the voltage is stably applied to the pixel electrode 116. Accordingly, it is possible to improve the problem of the contrast ratio and the uniformity of the image quality due to the asymmetry of the diode whose voltage varies depending on the polarity.

Semi-transmissive diode substrate according to an embodiment of the present invention having such a configuration is formed in a four mask process as follows.

4A and 4B illustrate a plan view and a cross-sectional view for describing a first mask process in a method of manufacturing a transflective diode substrate according to an exemplary embodiment of the present invention.

4A and 4B, the pixel electrode 116 and the first electrodes 132a and 132b connected thereto are formed on the lower substrate 112 by a first mask process.

Specifically, a transparent conductive material such as ITO, TO, IZO, or the like is deposited on the lower substrate 112 through a deposition method such as a sputtering method. The stacked transparent conductive material is patterned by a photolithography process and an etching process using a first mask to form the pixel electrode 116 and the first electrodes 132a and 132b connected thereto.

5A and 5B illustrate a plan view and a cross-sectional view for describing a second mask process in the method of manufacturing a transflective diode substrate according to an embodiment of the present invention, and FIGS. 6A and 6B specifically illustrate the second mask process. The cross-sectional views for explanation are shown.

5A and 5B, the scan lines 114a and 114b and the scan pad electrode 146 on the lower substrate 112 on which the pixel electrode 116 and the first electrodes 132a and 132b are formed in the second mask process. ) And second electrodes 134a and 134b and insulating patterns 130 are formed below them. Accordingly, the diodes D1 and D2 including the first electrodes 132a and 132b, the insulating patterns 130, and the second electrodes 134a and 134b, the scan pad electrodes 146, and the insulating patterns 130 below them. Scan pads 144a and 144b are formed.

Referring to FIGS. 6A and 6B, the second mask process will be described in detail. The silicon nitride having a high silicon (Si) content on the pixel substrate 116 and the lower substrate 112 on which the first electrodes 132a and 132b are formed is described. An inorganic insulating material 170 such as (SiNx: H) is deposited. The scan metal material 172 such as Mo, Ti, Cu, Al (Nd), or the like is deposited on the inorganic insulating material 170 through a deposition method such as a sputtering method.

After the photoresist is applied on the scan metal material 172, the photoresist pattern 202 is formed as shown in FIG. 6A by exposing and developing the photoresist in a photolithography process using a second mask. The scan metal material 172 and the inorganic insulating material 170 are sequentially patterned by an etching process using the photoresist pattern 202, so that the scan lines 114a and 114b, the scan pad electrode 146, and the second electrode ( 134a and 134b and insulating patterns 130 below them are formed.

The photoresist pattern 202 remaining in the strip process is removed as shown in FIG. 6B.

7A and 7B illustrate a plan view and a cross-sectional view for describing a third mask process in the method of manufacturing a transflective diode substrate according to an embodiment of the present invention, and FIGS. 8A and 8B illustrate the third mask process in detail. The cross-sectional views for explanation are shown.

7A and 7B, an organic material pattern 138 having an embossed surface in the reflective region is formed by a third mask process.

Referring to FIGS. 8A and 8B, the third mask process will be described in detail using a deposition method such as spin coating on the scan lines 114a and 114b, the scan pad electrodes 146, and the second electrodes 134a and 134b. A photosensitive organic material 176, such as acrylic, is deposited.

Next, the organic material pattern 138 is formed by patterning the photosensitive organic material 176 by a photolithography process using a third mask. The photosensitive organic material 176 is removed in a transmission region corresponding to the transmission portion P1 of the third mask. In addition, the photosensitive organic material 176 is removed from the pad area corresponding to the transmissive part P1 of the third mask to expose the scan pad electrode 146. In addition, in the third mask, the remaining portion P2 except for the transmissive portion P1 has a structure in which the blocking portion and the diffractive exposure portion (or semi-transmissive portion) are repeated, and thus the photosensitive organic material 176 corresponds to the blocking portion. Thus, the patterned pattern has a structure in which the recessed portion and the recessed portion are recessed in correspondence with the projected portion and the diffractive exposure portion. Subsequently, by firing the photosensitive organic material 176 where the protrusions and the groove portions are repeated, an organic material pattern 138 having an embossed surface in the reflection region is formed.

9A and 9B illustrate a plan view and a cross-sectional view for describing a fourth mask process in a method of manufacturing a transflective diode substrate according to an embodiment of the present invention, and FIGS. 10A and 10B specifically illustrate a fourth mask process. The cross-sectional views for explanation are shown.

9A and 9B, the reflective electrode 142 is formed on the organic material pattern 138 by the fourth mask process.

Referring to FIGS. 10A and 10B, the fourth mask process is described in detail. A reflective metal 180 having a high reflectance such as AlNd or the like is deposited on the organic material pattern 138 by an increasing method such as sputtering. After the photoresist is applied on the reflective metal 180, the photoresist pattern 204 is formed as shown in FIG. 10A by exposing and developing the photoresist by a photolithography process using a fourth mask. The reflective metal 180 is patterned by an etching process using the photoresist pattern 204 to form the reflective electrode 142 on the organic material pattern 138.

Through the etching process described above, the reflective metal 180 of the transmission region is removed to form the transmission hole 152. In addition, the reflective metal 180 is removed from the pad area where the scan pad 144a is formed through the etching process to expose the scan pad electrode 146.

The photoresist pattern 204 remaining in the strip process is removed as shown in FIG. 10B.

As described above, the present invention can simplify the substrate structure or manufacturing process of the liquid crystal display panel by using a two-terminal diode as a switching element, compared to a three-terminal thin film transistor.

As described above, the semi-transmissive diode substrate and the manufacturing method thereof according to the present invention can simplify the substrate structure or the manufacturing process of the semi-transmissive liquid crystal display device by using a two-terminal diode as a switching element as compared to the three-terminal thin film transistor. have.

In addition, the semi-transmissive diode substrate and the method of manufacturing the same according to the present invention do not have a structure in which the data line and the scan line are intersected on one substrate, and thus there is an advantage in that short-circuit failure does not occur between two lines.

In addition, the present invention can increase the utilization of the diode switching device by applying the diode switching device to the substrate of the transflective liquid crystal display panel.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (8)

A pixel electrode formed on the substrate; An insulation pattern formed on the substrate; Scan lines formed on the insulating patterns; A diode connected to the pixel electrode and the scan line; An organic material pattern covering reflective regions of the scan line, the diode, and the pixel electrode; A semi-transmissive diode substrate comprising a reflective electrode overlapping the organic material pattern. The method of claim 1, The diode A first electrode connected to the pixel electrode; And a second electrode overlapping the first electrode with the insulating pattern interposed therebetween and connected to the scan line. The method of claim 1, The scan line is A first scan line adjacent to a first side of the pixel electrode; A second scan line adjacent to a second side of the pixel electrode; And the diode comprises a first diode connected with the first scan line and a second diode connected with the second scan line. The method of claim 1, Further comprising a scan pad connected with the scan line, The scan pad may include a scan pad electrode connected to the scan line and the insulating pattern overlapping a lower portion of the scan pad electrode. Forming a pixel electrode and a first electrode connected to the pixel electrode on the substrate using the first mask; A second pattern overlapping the insulating pattern on the substrate and the first electrode, the scan line overlapping the insulating pattern, and the first electrode and the insulating pattern interposed therebetween by using a second mask; Forming a diode comprising an electrode; Forming an organic material pattern covering a reflection area of the scan line, the diode, and the pixel electrode by using a third mask; And forming a reflective electrode overlapping the organic material pattern using a fourth mask. The method of claim 5, The scan line is A first scan line adjacent to a first side of the pixel electrode; And a second scan line adjacent to the second side of the pixel electrode. The method of claim 5, Forming the scan line and the second electrode by using the second mask And a scan pad electrode connected to the scan line simultaneously with the scan line and the second electrode. The method of claim 7, wherein Using the second mask And forming the insulating pattern having the same pattern as that of the scan pad electrode.

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