KR20040095106A - Reflection and penetration type array substrate - Google Patents

Abstract

PURPOSE: A transflective array substrate is provided to split a unit pixel into left and right parts to maximize optical characteristics of a reflection mode and a transmission mode. CONSTITUTION: A transflective array substrate includes a gate line(110) transmitting a scan signal, a data line(130) transmitting a data signal, the first gate electrode(112T) extended from the gate line, and the first switching element(TFT1) having the first data electrode(132T) extended from the data line. The transflective array substrate further includes the second gate electrode(112R) extended from the gate line, the second switching element(TFT2) having the second data electrode(132R) extended from the data line, the first pixel electrode(160T) connected to the first drain electrode(134T) to transmit artificial light that transmits a liquid crystal layer, the second pixel electrode(160R) connected to the second drain electrode(134R), and a reflecting plate(170) formed on the second pixel electrode to reflect natural light that transmits the liquid crystal layer.

Description

Reflective-transparent array substrates {REFLECTION AND PENETRATION TYPE ARRAY SUBSTRATE}

The present invention relates to a reflective-transmissive array substrate, and more particularly to a reflective-transmissive array substrate having left and right divided pixels.

In general, an array substrate employed in a reflection-transmissive liquid crystal display device has a reflector that reflects natural light in one pixel formed in a region defined by the gate line 10 and the data line 12, as shown in FIG. 14 and a transmission window 16 for transmitting the backlight (or artificial light) to turn on the backlight when the ambient light is dark to operate in the transmission mode, and to turn off the backlight when the ambient light is bright to operate in the reflection mode. .

Here, since the reflection efficiency and the transmission efficiency by the transmission mode are complementary to each other by the reflection mode, the optical characteristics of the reflection mode and the transmission mode cannot be fully satisfied in one pixel. However, in order to increase the efficiency, a multi-cell gap method or a multiple driving method has been proposed.

In the multi-cell gap method, the cell gaps of the reflection areas and the transmission areas are different from each other, so that the light path values when the light incident on the reflection areas is reflected and the light path values transmitted through the transmission areas are equally matched.

In addition, the multiple driving scheme maximizes the light efficiency by driving the reflection region and the transmission region at different voltages in the reflection-transmission mode of the multiple cell gap or the single cell gap.

However, in both schemes, since a boundary between a reflection area and a transmission area exists in one sub-pixel, there is a problem in that an afterimage occurs on the screen due to a light leakage phenomenon occurring throughout the frame at the boundary.

In addition, in the boundary between the reflection area and the transmission area, there is a problem in that a design margin must be secured in order to prevent a disclination phenomenon occurring at the beginning of the frame due to distortion of the liquid crystal alignment.

Accordingly, the present invention has been made in an effort to solve such a conventional problem, and an object of the present invention is to provide a reflection-transmissive array substrate for maximizing optical characteristics of a reflection mode and a transmission mode by dividing a unit pixel from side to side. will be.

1 is a view for explaining a general reflection-transmissive array substrate.

2 is a view for explaining a reflection-transmissive array substrate according to the present invention.

3A is a cross-sectional view taken along line AA ′ of FIG. 2, and FIG. 3B is a cross-sectional view taken along line BB ′ of FIG. 2.

FIG. 4 is a diagram for describing an equivalent circuit of the reflection-transmissive liquid crystal display device employing the reflection-transmission array substrate of FIG. 2.

5 is a view for explaining an example of pixel arrangement of a reflection-transmissive array substrate according to the present invention.

6 is a view for explaining another example of the pixel arrangement of the reflection-transmissive array substrate according to the present invention.

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

110: gate line 120: first gate insulating film

130: data line TFT1, TFT2: switching element

140: passivation film 150: organic film

160T: first pixel electrode 160R: second pixel electrode

170: reflector GL: gate line

DL: data line

The reflection-transmissive array substrate according to one feature for realizing the object of the present invention described above is a reflection-transmission array substrate that is employed in a liquid crystal display device for displaying an image using artificial light and natural light passing through the liquid crystal layer, A gate line transferring a scan signal; A data line carrying a data signal; A first switching element having a first gate electrode extending from the gate line and a first data electrode extending from the data line; A second switching element having a second gate electrode extending from the gate line and a second data electrode extending from the data line; A first pixel electrode connected to the first drain electrode of the first switching element and transmitting the artificial light; A second pixel electrode connected to a second drain electrode of the second switching element; And a reflector formed on the second pixel electrode to reflect the natural light.

According to such a reflection-transmissive array substrate, the unit pixel is divided into two sub-pixels from side to side based on the data line, and each of the divided sub-pixels has a switching element to maximize the optical characteristics of the reflection mode and the transmission mode. have.

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

2 is a view for explaining a reflection-transmissive array substrate according to the present invention.

Referring to FIG. 2, the reflective-transmissive array substrate according to the present invention may include a first switching element TFT1 formed in one direction based on the gate line 110, the data line 130, and the gate line 110, and the gate. A second switching element TFT2 formed in the other direction based on the line 110, a first pixel electrode 160T electrically connected to the first switching element TFT1, and a second switching element TFT2 electrically connected to the second switching element TFT2. The reflective plate 170 is formed on the second pixel electrode 160R and the second pixel electrode 160R.

The gate line 110 extends in a horizontal direction on a substrate (not shown), and transmits a scan signal to the first switching element TFT1 and the second switching element TFT2, respectively.

The data line 130 extends in the vertical direction on the substrate, and transmits a data signal to the first switching element TFT1 and the second switching element TFT2, respectively.

The first switching element TFT1 includes a first gate electrode 112T extending from the gate line 110, a first data electrode 132T extending from the data line 130, and the first data electrode ( A first drain electrode 134T spaced apart from the 132T by a predetermined interval is electrically connected to the first pixel electrode 160T. Here, the illustration of the active layer or the semiconductor layer formed on the active layer is omitted.

The second switching element TFT2 may include a second gate electrode 112R extending from the gate line 110, a second data electrode 132R extending from the data line 130, and the second data electrode ( The second drain electrode 134R is spaced apart from the 132R by a predetermined distance, and is electrically connected to the second pixel electrode 160R. The illustration of the active layer or the semiconductor layer formed on the active layer is omitted.

The first pixel electrode 160T is connected to the first drain electrode 134T of the first switching element TFT1 to transmit artificial light provided from the bottom, and transmits a data signal through the first switching element TFT1. Are provided. The above-mentioned data signal causes a potential difference with the color filter substrate to be formed in the future, and the induced potential difference is applied across the liquid crystal layer to transmit the artificial light.

The second pixel electrode 160R is connected to the second drain electrode 134R of the second switching element TFT2 to receive a data signal via the second switching element TFT2, and the reflector 170 is formed of a second pixel electrode 160R. It is formed on the two pixel electrode 160R and reflects the natural light provided from the top. The data signal causes a potential difference with the color filter substrate to be formed in the future, and the induced potential difference is applied across the liquid crystal layer to transmit the above natural light.

As described above, instead of disposing a data line at the left end of a pixel as in a conventional unit pixel structure, the unit pixel is divided into two subpixels by passing a data line inside the unit pixel, and each of the divided subpixels. To form a switching element for driving.

One of the switching elements is a switching element connected to the transmission-only sub-pixel, and the other switching element is a switching element connected to the reflection-only sub-pixel. Of course, from the driving point of view, the source electrode of each switching element is connected to one data line, and the gate electrode is also connected to one gate line, so the above-mentioned transmission subpixel and reflection subpixel are unit pixels.

In addition, the area ratio of the transmission region and the reflection region can be adjusted to the position of the data line. For example, to increase the area of the transmissive region, the position of the data line is shifted to the right, and to increase the area of the reflective region, the position of the data line is shifted to the left.

In addition, the size of the switching element included in the unit pixel may be reduced to 1/2 of the size of the switching element before the division by applying the divided pixel structure that is divided left and right based on the data line.

3A is a cross-sectional view taken along line AA ′ of FIG. 2, and FIG. 3B is a cross-sectional view taken along line BB ′ of FIG. 2.

First, referring to FIG. 3A, in some regions of the substrate 105, a first gate electrode 112T, a first gate insulating layer 120 formed on the first gate electrode 112T, and a first active layer 122T are formed. And a first switching element TFT1 including a first semiconductor layer 124T, a first source electrode 132T, and a first drain electrode 134T, and a second gate electrode in another region on the substrate 105. 112R, a second gate insulating layer 120 formed on the second gate electrode 112R, a second active layer 122R, a second semiconductor layer 124R, a second source electrode 132R, and a second drain The second switching element TFT2 including the electrode 134R is formed.

A portion of the first drain electrode 134T and a portion of the second drain electrode 134R cover the first switching element TFT1 and the second switching element TFT2, respectively, and the first contact hole 152 and the second contact, respectively. The passivation layer 140 formed to be exposed through the hole 154, and the organic layer exposing a portion of the first drain electrode 134T and a portion of the second drain electrode 134R while covering the passivation layer 140. The film 150 is formed.

The first pixel electrode 160T is formed to correspond to the reflective region on the organic layer 150, and is connected to the first drain electrode 134T of the first switching element TFT1, and the second pixel electrode corresponds to the transmissive region. A 160R is formed to be connected to the second drain electrode 134R of the second switching element TFT2, and a reflecting plate 170 is formed on the second pixel electrode 160R. Here, the first and second pixel electrodes 106T and 160R are a kind of transmissive electrode that transmits light, and an ITO or IZO material is used, and the reflector plate 170 is a kind of reflecting electrode that reflects light. It is preferable to use an alloy or the like.

In the drawing, the surface of the organic film 150 is unevenly processed, so that the unevenness corresponding to the transmissive region acts as a kind of micro-transmissive lens to scatter artificial light, and the unevenness corresponding to the reflective region causes the reflecting plate 170 to be a micro reflective lens. It has been shown to scatter natural light by forming it to operate. However, those skilled in the art may planarize the surface of the protective film described above.

On the other hand, in the reflection-transmissive array substrate having the divided pixel structure according to the present invention, it is preferable to adopt a front gate method, as shown in Figure 3b to maximize the transmission efficiency.

As shown in FIG. 3B, a passivation film 140 is formed on the transmissive region side front gate line 114T and the reflective region side front gate line 114R that are divided by data lines on the substrate 105, and the passivation layer formed thereon. A separate first metal layer 147T and a second second metal layer 147R are formed on the transmissive region side of the film 140.

The transmissive region side storage capacitor is defined by the transmissive region side front gate line 114T and the first metal layer 147T, and the reflective region is defined by the reflective region side front gate line 114R and the second metal layer 147R. Side storage capacitors are defined. That is, when viewed from the plane of the array substrate, the capacitance of the storage capacitor may be defined by a region where the front gate line and the metal layer overlap and the distance between the front gate line and the metal layer.

On the passivation layer 140 and the first and second metal layers 147T and 147R, an organic film 150 having a concave-convex surface is formed, and the first pixel electrode 160T corresponding to the transmissive region has a third contact hole. The first pixel layer 147T is connected to the first metal layer 147T via 116T, and the second pixel electrode 160R corresponding to the reflective region is connected to the second metal layer 147R via the fourth contact hole 116R. .

As described above, in the reflection-transmissive array substrate having the divided pixel structure according to the present invention, as shown in FIG. 4 below, by using the front gate line as the electrode for the storage capacitor, the transmission efficiency can be maximized.

In addition, when the divided pixel structure is applied according to the present invention, it is necessary to design the switching element to have a different additional capacitance according to the divided sub pixel area since the size of the switching element is reduced to 1/2 compared to the size of the switching element before the division. Of course, by adjusting the overlapping region of the front gate line and the metal layer corresponding to the transmissive region, and the overlapping region of the front gate line and the metal layer corresponding to the reflective region, the storage capacitance and reflection only corresponding to the transmissive sub-pixel are adjusted. The storage capacitance corresponding to the sub pixel can be adjusted differently.

FIG. 4 is a diagram for describing an equivalent circuit of the reflection-transmissive liquid crystal display device employing the reflection-transmission array substrate of FIG. 2.

Referring to FIG. 4, the reflection-transmissive liquid crystal display according to the present invention extends in a horizontal direction, is arranged in a vertical direction, and transmits a scan signal for controlling on / off of connected switching elements TFT1 and TFT2. A plurality of data lines Dp that transfer image signals to the pixel electrodes via the plurality of gate lines Gg-1 and Gq, and extend in the vertical direction, arranged in the horizontal direction, and connected to the switching elements TFT1 and TFT2. -1, Dp, Dp + 1).

A first switching element TFT1 is connected to an arbitrary gate line Gq and an arbitrary data line Dp, and a liquid crystal capacitor Clc and a storage capacitor Cst are connected to a drain electrode of the first switching element TFT1. A first pixel electrode (or transmissive sub-pixel) 160T connected to operate as a kind of transmissive electrode is defined. Here, one end of the storage capacitor Cst is connected to the drain electrode of the first switching element TFT1 and the other end has a front gate method connected to the previous gate line Gq-1.

A second switching element TFT2 is connected to an arbitrary gate line Gq and an arbitrary data line Dp, and a liquid crystal capacitor Clc and a storage capacitor Cst are connected to a drain electrode of the second switching element TFT2. A second pixel electrode (or reflection dedicated sub-pixel) 160R connected to operate as a kind of reflective electrode is defined. Here, one end of the storage capacitor Cst is connected to the drain electrode of the second switching element TFT2 and the other end has a front gate method connected to the previous gate line Gq-1.

As described above, the transmission region and the reflection region can be driven using different switching elements for the liquid crystal display device employing the single cell gap structure or the liquid crystal display device employing the multiple cell gap structure.

That is, since the transmittance characteristic relative to the voltage corresponding to the transmissive region and the transmittance characteristic relative to the voltage corresponding to the reflective region are usually different, it can be driven at a voltage that is optimal for the transmissive or reflective mode.

5 is a view for explaining an example of pixel arrangement of a reflection-transmissive array substrate according to the present invention.

Referring to FIG. 5, from an observer's point of view, a reflection-only sub-pixel (hatched) R (p-1, q), R is located in the left region of every data line DLp-1, DLp, DLp + 1, DLp + 2. (p-1, q + 1), R (p, q), R (p, q + 1) ...), and in the right region, the transmissive sub-pixels T (p-1, q), T (p-1, q + 1), T (p, q), T (p, q + 1) ...) are formed. Of course, the reverse is also possible.

A separate floating metal line FL is further formed between the reflective sub-pixel and the transmissive sub-pixel to block the occurrence of declining through the interface between the transmissive region and the reflective region. The floating metal line FL may be formed when the data line is formed, or may be defined by forming a separate metal layer between pixel electrodes spaced apart at regular intervals between the transmission area and the reflection area.

In particular, even when applied to a liquid crystal display device having a multi-cell gap structure that implements a cell gap corresponding to a reflective region and a cell gap corresponding to a transmissive region differently, the generated declining can be blocked using the floating metal line. .

In addition, even after the multi-cell gap structure is applied to the liquid crystal display device employing the single cell gap structure, the generated afterimage may be blocked by using the floating metal line.

In the above, it is illustrated that the reflection-only subpixel is formed in the left or right region and the transmission-only subpixel is formed in the right or left region based on an arbitrary data line. However, those skilled in the art can arrange various combinations of reflection-only subpixels and transmission-only subpixels.

6 is a view for explaining another example of the pixel arrangement of the reflection-transmissive array substrate according to the present invention.

Referring to FIG. 6, a transmissive sub-pixel is formed in the left region of the odd-side data lines DLp-1 and DLp + 1 from an observer's point of view, and the right-side of the odd-side data lines DLp-1 and DLp + 1. A reflection dedicated sub pixel is formed in an area, a reflection dedicated sub pixel is formed in a left area of the even-side data lines DLp and DLp + 2, and a light is transmitted through the right area of the even-side data lines DLp and DLp + 2. A dedicated sub pixel is formed.

A separate floating metal line FL may be further formed between the transmission-only sub-pixel and the reflection-only sub-pixel to block the occurrence of declining through the interface between the transmission area and the reflection area. The floating metal line FL may be formed when the data line is formed, or may be defined by forming a separate metal layer between pixel electrodes spaced apart at regular intervals between the transmission area and the reflection area.

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

As described above, according to the present invention, by dividing a unit pixel into two sub-pixels from side to side on the basis of a data line, and by providing a switching element in each of the divided sub-pixels, a transmissive region and a different switching element are used. The reflection area can be driven, and the size of the switching element can be relatively reduced, thereby increasing the area of the transmission area to maximize the optical characteristics of the reflection mode and the transmission mode.

In addition, in the liquid crystal display device employing the multi-cell gap structure, as the cell gap of the transmissive region increases, the liquid crystal capacitance decreases and the size of the additional capacitance decreases, thereby further reducing the size of the switching element.

In addition, considering that the transmissive region and the reflective region have different transmittance characteristics relative to voltage, not only the liquid crystal display device employing a single cell gap structure but also the liquid crystal display device employing a multi-cell gap structure have different transmission and reflection areas. Since it can be driven using a switching element, it is possible to drive a multi-voltage method.

Claims (5)

In a reflection-transmissive array substrate employed in a liquid crystal display device displaying an image using artificial light and natural light passing through the liquid crystal layer, A gate line transferring a scan signal; A data line carrying a data signal; A first switching element having a first gate electrode extending from the gate line and a first data electrode extending from the data line; A second switching element having a second gate electrode extending from the gate line and a second data electrode extending from the data line; A first pixel electrode connected to the first drain electrode of the first switching element and transmitting the artificial light; A second pixel electrode connected to a second drain electrode of the second switching element; And And a reflection plate formed on the second pixel electrode and reflecting the natural light. The display device of claim 1, wherein the first pixel electrode is defined as a transmissive region, and the second pixel electrode is defined as a reflective region. And the ratio of the transmission area to the reflection area is defined according to the position of the data line. The reflective-transmissive array substrate of claim 1, wherein the first pixel electrode is defined as a first liquid crystal capacitor and a first storage capacitor, and the first storage capacitor is connected to a front gate line. The reflective-transmissive array substrate of claim 1, wherein the second pixel electrode is defined as a second liquid crystal capacitor and a second storage capacitor, and the second storage capacitor is connected to a front gate line. The method of claim 1, wherein different data signals are applied to the first and second pixel electrodes in consideration of a voltage-transmittance characteristic corresponding to a transmission region and a voltage-transmission characteristic corresponding to a reflection region. Transmissive Array Substrate.