KR20070082636A - Display panel - Google Patents

Abstract

A display panel is provided to optimize a display characteristic and improve stability and productivity by forming a liquid crystal layer with a substantially uniform cell gap. An array substrate(100) is divided into a reflective area(RFA1,RFA2) and a transmissive area(TA), and includes a first organic layer formed in the reflective area with a first thickness and having an uneven pattern, and a second organic layer formed in the transmissive area with a second thickness different from the first thickness. A color filter substrate(200) faces the array substrate, and includes a color filter layer including an aperture(LH1) corresponding to the reflective area. A liquid crystal layer(300) is interposed between the array substrate and the color filter substrate, and has a cell gap of the transmissive area the same as or greater than a cell gap of the reflective area.

Description

Display panel {DISPLAY PANEL}

1 is a plan view of a display panel according to a first exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of the display panel according to the first exemplary embodiment cut along the line II ′ of FIG. 1.

3 is a cross-sectional view of a display panel according to a second exemplary embodiment of the present invention.

4 is a plan view of a display panel according to a third exemplary embodiment of the present invention.

FIG. 5 is a cross-sectional view of the display panel according to the third exemplary embodiment cut along the line II-II ′ of FIG. 4.

6 is a cross-sectional view of a display panel according to a fourth exemplary embodiment of the present invention.

7 and 8 are cross-sectional views illustrating patterning of a mask and an organic layer for forming a display substrate according to a first exemplary embodiment of the present invention.

9 and 10 are cross-sectional views illustrating patterning of a mask and an organic layer for forming a display substrate according to a second exemplary embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

100: array substrate SL1: first storage wiring

SL2: Second storage wiring RFA1, RFA2: Reflective area

TA: Transmission area RFE1, RFE2: Reflective electrode

PE: pixel electrode OL1, OL2, OL3: organic layer

CNT1, CNT2: Contact hole LH1, LH2: Opening

The present invention relates to a display panel, and more particularly, to a display panel that can optimize display characteristics and improve productivity.

In general, liquid crystal displays are classified into transmissive LCDs, reflective LCDs, and transflective LCDs according to a method of using light.

The transflective liquid crystal display device includes a liquid crystal display panel displaying an image by back light and external light and a backlight assembly providing back light to the liquid crystal display panel. The liquid crystal display panel includes a plurality of unit pixels for displaying an image, and each unit pixel includes a transmission region for displaying an image using back light and a reflection region for displaying an image by reflecting external light through a reflective electrode. Include. Light incident on the reflective region is reflected by the reflective electrode made of a metal material, and thus passes through the liquid crystal layer and the color filter layer twice. As a result, since a light path difference with the transmission region occurs, color purity and luminance of the display screen are uneven, resulting in a decrease in display quality.

Recently, in order to solve this problem, a double cell gap structure is used in which the liquid crystal cell gaps of the transmissive and reflective areas are different. However, problems such as a decrease in yield due to process difficulties and light loss due to a misalignment of the liquid crystal orientation of the stepped portion are solved. Holding In addition, a circuit solution for applying a voltage differently according to an external light environment has been proposed, but it is difficult to commercialize due to a burden on an additional circuit.

Accordingly, the technical problem of the present invention was conceived in this respect, and an object of the present invention is to provide a display panel for optimizing display characteristics and improving stability and productivity.

According to an exemplary embodiment of the present invention, a display panel is divided into a reflection area and a transmission area, and a first organic layer having a first thickness having an uneven pattern is formed in the reflection area, and the first display layer is formed in the transmission area. An array substrate including a second organic film having a second thickness different from one thickness, a color filter substrate including a color filter layer facing the array substrate and having an opening corresponding to the reflection area, and between the array substrate and the color filter substrate; And a liquid crystal layer interposed therebetween and having a cell gap greater than or equal to the cell gap of the reflective region. According to such a display panel, display characteristics can be optimized, and stability and productivity can be improved.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention.

1 is a plan view of a display panel according to a first exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view of the display panel according to the first exemplary embodiment cut along the line II ′ of FIG. 1.

1 and 2, the display panel 500 includes an array substrate 100, a color filter substrate 200 formed to face the array substrate 100, an array substrate 100, and a color filter substrate 200. It includes a liquid crystal layer 300 interposed between.

The array substrate 100 includes a gate line GL, a source line, a storage line SL, and a switching element TFT. The gate lines GL are formed to extend in the first direction D1, and a plurality of gate lines GL are formed in parallel in the second direction D2. Here, the first direction D1 and the second direction D2 are preferably perpendicular.

The gate line GL is electrically connected to the gate electrode G of the switching element TFT, and applies a gate signal transmitted from the gate line GL to the gate electrode G of the switching element TFT. The gate electrode G is formed of the same metal layer as the gate line GL and extends from the gate line GL. The gate line GL may be formed of, for example, a metal such as chromium, aluminum, tantalum, molybdenum, titanium, tungsten, copper, or silver, or an alloy thereof, and may be formed of two or more layers having different physical properties. Can be.

The storage wiring extends in the first direction D1 and is formed in the pixel region P to have a predetermined width in the second direction D2. The storage wiring is made of the same metal material as the gate wiring GL and the gate electrode G, and is formed simultaneously with the gate wiring GL and the gate electrode G. The storage line includes a first storage line SL1 and a second storage line SL2 formed in parallel.

The first storage line SL1 is applied with the same voltage as the pixel electrode PE by a first storage capacitor formed together with the drain electrode D, and the second storage line SL2 is a storage electrode as a storage capacitor. The PE and the second storage line SL2 are directly connected to form a second storage capacitor, and apply a voltage divided by the first storage capacitor.

The source wiring DL is formed to extend in the second direction D2, and a plurality of source wirings DL are formed in parallel in the first direction D1. The source wiring DL is electrically connected to the source electrode S of the switching element TFT, and a data signal transmitted from the source wiring DL is applied to the source electrode S of the switching element TFT. The source electrode S and the drain electrode D are formed of the same metal layer as the source wiring DL, and the source electrode S extends from the source wiring DL.

In this case, as the plurality of gate lines GL and the plurality of source lines DL are formed to cross each other, the unit pixel P is defined. The switching element TFT and the pixel electrode PE are formed in the unit pixel P.

The switching element TFT includes a gate electrode G, a source electrode S, and a drain electrode D. FIG. The gate electrode G is branched from the gate line GL in the second direction D2 and is formed of the same metal material as the gate line GL. The source electrode S is branched from the source wiring DL in a direction opposite to the first direction D1. In addition, the drain electrode D is formed to be spaced apart from the source electrode S, and is electrically connected to the pixel electrode PE.

The unit pixel P is divided into a first reflection area RFA1, a second reflection area RFA2, and a transmission area TA. The first reflection area RFA1 is an electrical connection between the first storage line SL1, the drain electrode D, the pixel electrode PE, and the first reflection electrode RFE1 formed on the pixel electrode PE. One contact hole CNT1 is included. The second reflection area RFA2 electrically connects the second storage wire SL2, the second storage wire SL2, the pixel electrode PE, and the second reflection electrode RFE2 formed on the pixel electrode PE. And a second contact hole CNT2.

The color filter substrate 200 includes a black matrix pattern BM, a color filter CF, an opening LH, a planarization layer 220, and a common electrode CE. The black matrix pattern BM is disposed near the boundary of each pixel to separate the RGB of the unit pixel P, and passes through the liquid crystal in an area that is not controlled by the pixel electrode PE formed on the array substrate 100. Block out light.

The color filters CF are formed on the color filter substrate 200 to face the pixel regions P formed by crossing the gate lines GL and the source lines DL formed on the array substrate 100. . The color filters CF include a red color filter CF that emits red light included in white light, a green color filter CF that emits green light included in white light, and a blue light included in white light. It includes a blue (B) color filter (CF) for emitting. Color filters CF are repeatedly disposed in the opening of the black matrix pattern to form a color filter pattern.

The color filters CF further include an opening LH. The opening LH is formed in the color filter CF extending in the first direction D1 and may have a different size depending on the degree of color implementation of the color filter CF. The opening LH is formed by patterning the color photoresist in the process of forming the color filter CF by the photolithography method.

Since the planarization layer 220 has a thickness difference between the black matrix BM and the color filter CF, the planarization layer 220 is formed to cover the black matrix BM and the color filter CF in a vertical line parallel to the base substrate 210. It is preferable.

The common electrode CE is formed to cover the black matrix BM and the color filter CF. The common electrode CE is transparent and conductive, for example, indium tin oxide (ITO), indium zinc oxide (IZO), and amorphous indium zinc oxide (a-ITO). ) Is formed.

The liquid crystal layer 300 is formed by interposing a plurality of liquid crystal molecules between the array substrate 100 and the color filter substrate 200. There are horizontal alignment, vertical alignment, and twisted alignment according to the initial alignment state of the plurality of liquid crystal molecules, and the plurality of liquid crystal molecules include the pixel electrode PE of the array substrate 100 and the common electrode of the color filter substrate 200. The plurality of liquid crystal molecules may have a constant molecular arrangement state by an alignment layer (not shown) formed on CE.

The liquid crystal display panel having the transmissive area TA and the reflective areas RFA1 and RFA2 in the pixel area P has a liquid crystal display panel of the transmissive area TA and the reflective areas RFA1 and RFA2 in the liquid crystal layer 300. Although there is a difference in the optical path, even if the thickness of the single liquid crystal layer 300 is formed by including the first capacitor and the second capacitor formed by the first storage line SL1 and the second storage line SL2, the transflective mode Can be implemented.

In this case, the second capacitor serves as an auxiliary capacitor for the first capacitor by applying the divided voltage and the voltage applied to the first reflection area RFA1 including the transmission area TA and the first capacitor.

Referring to FIG. 2, referring to the first embodiment of the present invention, the switching element TFT includes a gate electrode G, a source electrode S, and a drain electrode D. FIG. The gate insulating layer 120, the semiconductor layer 130, and the ohmic contact layer 140 are formed on the gate electrode G.

The reflective regions RFA1 and RFA2 include the storage lines SL1 and SL2, the gate insulating layer 120, the passivation layer 150, the organic layer OL1, and the pixel electrode PE. In the first reflective region RFA1, a drain electrode D is further formed on the gate insulating layer 120.

The first reflective region RFA1 includes a passivation layer 150 and a first contact hole CNT1 through which a portion of the organic layer OL1 is removed to expose the drain electrode D, and the second reflective region RFA2 A second contact hole CNT2 exposing the second storage line SL2 is electrically connected to the pixel electrode PE and the first reflective electrode RFE1 or the second reflective electrode RFE2. The transmission area TA includes a gate insulating layer 120, a passivation layer 150, an organic layer OL1, and a pixel electrode PE formed on the base substrate 110.

The first cell gap of the liquid crystal layer 300 is defined as the thickness between the first organic layer having the uneven pattern at the first thickness x and the common electrode CE formed in the opening LH1 of the color filter substrate 200. do. In addition, the second cell gap of the liquid crystal layer 300 is formed between the second organic layer having the flat pattern at the second thickness y and the common electrode CE formed on the color filter CF of the color filter substrate 200. It is defined as thickness.

The first organic layer is formed in the first and second reflective regions RFA1 and RFA2, and the liquid crystal layer 300 has a first cell gap a. In addition, the second organic layer is formed in the transmission area TA and the liquid crystal layer 300 has a second cell gap b. In this case, the second thickness y of the second organic layer is lower than the first thickness x of the first organic layer, so that the first cell gap a and the second cell gap b of the liquid crystal layer 300 are formed. You can do the same.

In the transflective mode, the liquid crystal and drive are first optimized to the transmissive region and the reflecting region is as close as possible to the optical characteristics of the transmissive region to optimize the display characteristics of the liquid crystal display panel. In this case, although the first cell gap a and the second cell gap b for optimizing the reflectance of the reflective region and the transmittance of the transmissive region at the same time may not have the same value, the thickness of the second organic layer may be determined. By forming lower than the thickness of the organic film, it is possible to realize a substantially single cell gap.

For example, even when the reflectance and the transmittance are optimized, the first cell gap a is about 3.2 μm and the second cell gap b is about 3.4 μm. Since the difference between the second cell gap b and the second cell gap b is about 0.2 μm, a liquid crystal display panel having a cell gap of a substantially single liquid crystal layer 300 may be implemented.

3 is a cross-sectional view of a display panel according to a second exemplary embodiment of the present invention.

Referring to FIG. 3, the organic layers OL2 of the first and second reflection regions RFA1 and RFA2 are formed of a first organic layer having an uneven pattern of the first thickness x. In addition, the organic layer OL2 of the transmission area TA is formed of a second organic film having the concave-convex pattern similarly to the first organic film. In this case, the first thickness x of the first organic film and the second thickness z of the second organic film have the same thickness. That is, the uneven pattern having the same thickness is formed on the entire base substrate 110.

The first reflecting region RFA1 and the second reflecting region RFA2 may optimize the reflectance at which light is reflected by the uneven pattern, and the transmissive area TA may transmit transmittance through which light is transmitted by the uneven pattern. Can be optimized As described above, the reflectance and the transmittance may be simultaneously optimized, and the first cell gap c of the liquid crystal layer 300 may be formed to be equal to or slightly smaller than the second cell gap d.

For example, when the first cell gap is about 3.3 μm while the display characteristics of the transmissive area including the uneven pattern are optimized, the cell gap of the reflective area may also be optimized at about 3.3 μm. As a result, a liquid crystal display panel having a cell gap of the substantially single liquid crystal layer 300 may be implemented.

4 is a plan view of a display panel according to a third exemplary embodiment of the present invention, and FIG. 5 is a cross-sectional view of the display panel according to the third exemplary embodiment cut along the line II-II ′ of FIG. 4.

4 and 5, the display panel 600 includes an array substrate 100, a color filter substrate 200, and a liquid crystal layer 300, and the color filter substrate 200 has a plurality of opening holes. The opening LH2 is formed. The opening LH2 is formed by removing a part of the color filter CF, and the planarization layer 220 and the common electrode CE are formed on the opening LH2. In this case, the opening LH2 extends in the first direction D1, and a plurality of openings are formed in the second direction D2. As the opening LH2 is formed by removing a part of the color filter CF, a step is formed with the color filter CF.

At this time, even if the planarization layer 220 is formed to have a predetermined thickness on the entire surface of the base substrate 210, the planarization layer 220 is formed at a portion where the opening LH2 is formed by the step between the opening LH2 and the color filter CF. This can not be maintained at a constant thickness. In contrast, the plurality of openings may be formed in the opening LH2 to minimize the difference between the opening LH2 and the color filter CF.

Accordingly, even if the second thickness w of the second organic film of the transmissive area TA is higher than the first thickness x of the first organic film of the reflective areas RFA1 and RFA2 in the transflective mode, the plurality of the plurality of the plurality of second organic films may be formed. The opening LH2 including the opening holes of the first cell gap e and the second cell gap f of the liquid crystal layer 300 may be formed at the same or very small difference. For example, when the display characteristics of the transmissive region are optimal, the first cell gap e may be formed to about 3.4 μm, and the second cell gap f may be formed to about 3.3 μm. A liquid crystal display panel having a cell gap of 300 may be implemented.

6 is a cross-sectional view of a display panel according to a fourth exemplary embodiment of the present invention.

Referring to FIG. 6, the first thickness x of the first organic layer of the organic layer OL1 is lower than the second thickness y of the second organic layer including the uneven pattern, and the color filter substrate 200 is formed. The openings LH2 are formed to include the plurality of openings.

Alternatively, by simultaneously applying the second embodiment and the third embodiment, the first organic film of the organic layer OL2 is formed in the same manner as the second organic film including the uneven pattern, and the color filter substrate 200 The opening LH2 is formed to include the plurality of openings.

That is, the display characteristics of the transmissive region and the reflective region are optimized, and the organic layer OL1 and OL2 of the array substrate 100 and the opening LH2 of the color filter substrate 200 are deformed so that the liquid crystal layer 300 can be formed. The first cell gap g and the second cell gap h may be formed at the same or very slight difference.

7 and 8 are cross-sectional views illustrating patterning of a mask and an organic layer for forming a display substrate according to a first exemplary embodiment of the present invention.

Referring to FIG. 7, the array substrate 100 may form a first metal layer (not shown) on the base substrate 110, and pattern the first metal layer with a mask (not shown) to form the gate electrode G and the first substrate. A gate pattern including the first storage line SL1 and the second storage line SL2 is formed. A gate insulating layer 120 is formed on the gate pattern. The gate insulating layer 120 is made of, for example, a silicon nitride film (SiNx) or a silicon oxide film (SiOx).

Subsequently, the semiconductor layer 130 and the ohmic contact layer 140 are formed, and the semiconductor layer 130 and the ohmic contact layer 140 are patterned by a mask (not shown). The semiconductor layer 130 is made of, for example, amorphous silicon (a-Si). The ohmic contact layer 140 is made of, for example, amorphous silicon (n + a-Si) doped with a high concentration of n-type impurities. A second metal layer (not shown) is formed on an entire surface of the base substrate 110 including the semiconductor layer 130 and the ohmic contact layer 140, and the source metal S is formed by using a mask (not shown). ) And the drain electrode D formed to be spaced apart from the source electrode S.

The passivation layer 150 is coated on the entire surface of the base substrate 110 including the source pattern, and the organic layer 160 is formed on the passivation layer 150. In this case, the mask 400 is disposed on the organic layer 160 to pattern the organic layer 160. The first mask 400 is a half tone mask including a transflective region 410, slit regions 420a, 420b, and 420c and opening regions 430a and 430b.

The transflective region 410 is formed to correspond to the switching element TFT and the transmissive region TA of the array substrate 100, and the slit regions 420a, 420b, and 420c correspond to the first and second reflective regions RFA1, The opening regions 430a and 430b are formed to correspond to the RFA2, and the opening regions 430a and 430b are formed to correspond to the first and second contact holes CNT1 and CNT2. At this time, the slit regions 420a, 420b, and 420c form a slit by repeating arrangement of the semi-transmissive region and the blocked region.

When the amount of light passing through the opening areas 430a and 430b is 100%, the amount of light passing through the transflective area 410 is relatively less than the amount of light passing through the opening areas 430a and 430b and is blocked. The amount of light passing through the region (not shown) is relatively higher, for example, about 50%. At this time, the amount of light passing through the slit areas 420a, 420b, and 420c is relatively less than the amount of light passing through the transflective area 410 and is greater than the amount of light passing through the blocking area, for example, 30%. It is enough.

Referring to FIG. 8, the organic layer 160 corresponding to the opening regions 430a and 430b is completely exposed and removed, and the organic layer 160 corresponding to the semi-transmissive region 410 has a predetermined thickness and is partially removed. The organic layer 160 remains flat. In addition, the organic layer 160 corresponding to the slit regions 420a, 420b, and 420c is patterned into an organic layer having an uneven pattern as the organic layer 160 repeatedly corresponds to the semi-transmissive and blocked regions. The transflective region 410 of the first mask 400 is formed on the transmissive region TA of the array substrate 100 to have a thickness y that is lower than the thickness x of the uneven pattern and has a flat pattern. The organic layer OL1 may be formed.

Meanwhile, the organic layer as described above may be patterned through two processes of the first mask and the second mask. The organic layer 160 of the first and second reflection areas RFA1 and RFA2 and the transmission area TA are left through the first mask including the blocking area and the opening area. Subsequently, the organic layer 160 may be patterned using the second mask including the slit region and the opening region.

2 and 8, a portion of the passivation layer 150 is removed using the patterned organic layer OL1 as a mask to form first and second contact holes CNT1 and CNT2. Subsequently, the pixel electrode PE is formed on the entire surface of the base substrate 110. The pixel electrode PE is transparent and conductive, for example, indium tin oxide (ITO), indium zinc oxide (IZO), and amorphous indium zinc oxide (a-ITO). ) Is formed.

An array substrate 100 is fabricated by forming a first reflection electrode RFE1 and a second reflection electrode RFE2 on the pixel electrode PE in the first reflection region RFA1 and the second reflection region RFA2, respectively. The first and second reflective electrodes RFE1 and RFE2 are formed of a transparent and conductive material, such as the pixel electrode PE.

9 and 10 are cross-sectional views illustrating patterning of a mask and an organic layer for forming a display substrate according to a second exemplary embodiment of the present invention. Referring to FIG. 9, the organic layer 160 is formed on the entire surface of the base substrate 110 including the passivation layer 150, and the slit regions 510a, 510b, 510c and the opening region (top) of the organic layer 160. A halftone mask 500 including 520a and 520b is disposed.

The opening regions 520a and 520b are formed to correspond to the first contact hole CNT1 and the second contact hole CNT2, and the slit regions 510a, 510b and 510c are the first and second reflection regions RFA1 and RFA2. ) And the transmission area TA. Accordingly, the organic layer 160 of the first contact hole CNT1 and the second contact hole CNT2 is completely removed, and the organic layer 160 corresponding to the slit regions 510a, 510b, and 510c has an uneven pattern OL2. Is patterned as: Accordingly, the first and second reflective regions RFA1 and RFA2 and the transmission region TA have the organic layer OL2 having the uneven pattern having a thickness.

Referring to FIG. 10, a portion of the passivation layer 150 is removed using the patterned organic layer OL2 as a mask to form first and second contact holes CNT1 and CNT2. Subsequently, the pixel electrode PE is formed on the entire surface of the base substrate 110, and the first and second reflective electrodes RFE1 and RFE2 are formed to manufacture the array substrate 100.

As described in detail above, in the transflective mode liquid crystal display panel including the first storage capacitor and the second storage capacitor, the second thickness of the second organic layer of the transmission area TA of the array substrate 100 is reflected. Difference between the first cell gap of the reflection areas RFA1 and RFA2 and the second cell gap of the transmission area TA by lowering the first thickness of the first organic film of RFA1 and RFA2 or by forming an uneven pattern with the same thickness. Can be minimized. In addition, the plurality of opening holes may be formed in the opening LH2 of the color filter substrate 200 to minimize the difference between the first cell gap of the reflection areas RFA1 and RFA2 and the second cell gap of the transmission area TA. have.

According to such a display panel, the cell gap of the transmissive region of the array substrate and the cell gap of the reflective region are minimized to realize the cell gap of a single liquid crystal layer, thereby optimizing display characteristics, and achieving stability and productivity of the display panel. Can improve.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (6)

An array substrate having a first organic film having a first thickness having a concavo-convex pattern formed in the reflective region, and a second organic film having a second thickness different from the first thickness in the reflective region; A color filter substrate facing the array substrate, the color filter substrate including a color filter layer having an opening corresponding to the reflection area; And And a liquid crystal layer interposed between the array substrate and the color filter substrate and having a cell gap greater than or equal to the cell gap of the reflective region. The method of claim 1, wherein the array substrate is First storage wiring; A second storage interconnection formed in parallel with the first storage interconnection; A switching element connected to the gate line and the source line and including a drain electrode overlapping the first storage line; A transparent electrode electrically connected to the drain electrode; A first reflective electrode formed on the transparent electrode to cover the first storage wiring, defining the reflective region and electrically connected to the drain electrode; And And a second reflective electrode formed on the transparent electrode so as to cover the second storage wire and defining the reflective area and electrically connected to the second storage wire. The display panel of claim 2, wherein a flat pattern etched by a predetermined thickness is formed on the second organic layer, and the second thickness is smaller than the first thickness. The display panel of claim 2, wherein the uneven pattern is formed on the second organic layer, and the second thickness is the same as the first thickness. The display panel of claim 2, wherein the opening of the color filter substrate includes a plurality of opening holes. The display panel of claim 5, wherein the second thickness of the second organic layer is thicker than the first thickness.

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