KR101307996B1 - Transflective liquid crystal display device and fabricating method thereof - Google Patents

Abstract

According to the present invention, in forming the reflecting portion and the transmitting portion of the transflective liquid crystal display in a single cell gap, the reflective electrode on the first substrate and the common electrode on the second substrate corresponding to the transmitting portion are formed separately. A semi-transmissive liquid crystal display device and a method for manufacturing the same, which are driven by applying an individual common voltage to a separated common electrode, comprising: a first substrate including a plurality of pixel regions divided into a reflection part and a transmission part; A reflector formed on a reflector of the first substrate; A pixel electrode formed in the pixel region of the first substrate on which the reflective plate is formed; A second substrate bonded to the first substrate; A black matrix formed on the second substrate at predetermined intervals; A unit color filter formed between the black matrices on the second substrate; An overcoat layer formed on the second substrate on which the black matrix and the unit color filter are formed; And a common electrode formed on the second substrate on which the overcoat layer is formed, and separated into two corresponding to the reflecting portion and the transmitting portion formed on the first substrate, respectively, and separately driven by receiving a separate common voltage. It is characterized by.

Transflective, Single Cell Gap, Common Voltage

Description

Transflective liquid crystal display device and manufacturing method therefor {TRANSFLECTIVE LIQUID CRYSTAL DISPLAY DEVICE AND FABRICATING METHOD THEREOF}

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

2 is a perspective view of a first substrate and a second substrate of the transflective liquid crystal display according to the present invention.

FIG. 3 is a cross-sectional view of the W unit pixel viewed along a cut plane I-I 'illustrated in FIG.

4 is a view illustrating a common electrode formation pattern on a second substrate illustrated in FIG. 2.

5A to 5E are views illustrating a manufacturing process of the color filter viewed along the cut plane II-II ′ of FIG. 2.

Explanation of symbols on the main parts of the drawings

131: second substrate 132: black matrix

133a: W color filter 134: overcoat layer

135: common electrode 136: second alignment layer

The present invention relates to a transflective liquid crystal display device and a method for manufacturing the same. More particularly, the reflective part and the transmissive part of the transflective liquid crystal display device are formed in a single cell gap. And forming a common electrode on a corresponding second substrate, respectively, and applying a separate common voltage to the separated common electrode to drive the same.

 In general, a liquid crystal display device bonds two substrates on which electric field generating electrodes are formed to face each other, injects a liquid crystal material between the two substrates, and then applies liquid crystals to the liquid crystal molecules by applying a voltage to the two electrodes. By moving, it is a device for expressing the image by adjusting the transmittance of light that varies accordingly. However, as mentioned above, the liquid crystal display device requires a separate light source because it is a light receiving device that cannot emit light by itself. Therefore, a backlight device is provided on the rear surface of the liquid crystal panel and the light emitted from the backlight is incident on the liquid crystal panel to adjust the amount of light according to the arrangement of the liquid crystals to display an image. In this case, the field generating electrode of the liquid crystal display device is formed of a transparent conductive material, the two substrates should also be made of a transparent substrate.

Such a liquid crystal display device corresponds to a transmission type liquid crystal display device. Since an artificial back light source such as a backlight is used, a bright image may be realized even in a dark external environment, but power consumption due to the backlight is increased.

It is nonetheless a reflection type liquid crystal display device designed to compensate for this disadvantage. This is a form in which light transmittance is adjusted according to the arrangement of liquid crystals by reflecting external natural or artificial light, which consumes less power than a transmissive liquid crystal display. However, since the reflective liquid crystal display device has a structure in which most of the light is dependent on external natural light or artificial light sources, the reflective liquid crystal display device consumes less power than the transmissive liquid crystal display device but cannot be used in a dark place.

Accordingly, a liquid crystal display device having both a reflection and a transmission has been proposed as a device capable of appropriately selecting and using two modes of reflection and transmission.

Next, a general transflective liquid crystal display device will be described in detail with reference to the accompanying drawings. 1 is a partial cross-sectional view of a general transflective liquid crystal display device. As shown in the figure, the first substrate 11 and the second substrate 31 are arranged at a predetermined interval. First, a gate electrode 12 is formed on the first substrate 11 below the gate. The insulating film 13 is formed. Of course, before the gate insulating layer 13 is formed, a gate wiring connected to the gate electrode 12 is further formed below.

Next, the active layer 14 and the ohmic contact layers 15a and 15b are sequentially formed on the gate insulating layer 13, and the source and drain electrodes 16a and 16b are formed again on the ohmic contact layers 15a and 15b. The source and drain electrodes 16a and 16b are formed together with the gate electrode 12 to form a thin film transistor. Of course, here as before, a data line (not shown) of a material such as the source and drain electrodes 16a and 16b is additionally formed on the gate insulating layer 13, and the data line is connected to the source electrode 16a and the gate The pixel area is defined by crossing the wiring.

Subsequently, a first passivation layer 17 made of an organic material is formed on the source and drain electrodes 16a and 16b to cover the thin film transistor. In addition, a reflective plate 18 made of an opaque conductive material is formed in the pixel area on the first passivation layer 17, and a second passivation layer 19 is formed thereon. Here, the second protective layer 19 has a contact hole 19a exposing the drain electrode 16b together with the first protective layer 17.

A pixel electrode 20 made of a transparent conductive material is formed in the pixel area on the second protective layer 19, and the pixel electrode 20 is connected to the drain electrode 16b through the contact hole 19a. . The pixel electrode 20 here serves as a transmission electrode, of course. When the above process is completed, the first alignment layer 21 is subsequently formed.

On the other hand, a black matrix 32 is first formed on the second substrate 31, and then red, green, blue, and white colors are formed between the black matrices. The filters 33a and 33b are sequentially formed repeatedly. Here, one color as well as color filters 33a and 33b correspond to one pixel electrode 20, and the black matrix 32 covers edges of the thin film transistor and the pixel electrode 20.

An overcoat layer 34 is formed on the color filters 33a and 33b to protect and planarize the color filters 33a and 33b, and acrylic and polyimide resins are usually used.

Next, a common electrode 35 made of a transparent conductive material is formed on the overcoat layer 34, and a second alignment layer 36 is formed on the common electrode 35.

The liquid crystal layer 40 is positioned between the first and second alignment layers 21 and 36. The liquid crystal used here is usually a twisted nematic liquid crystal, and the liquid crystal molecules of the liquid crystal layer 40 41 is arranged uniformly with a pretilt angle with respect to the substrate.

However, in the case of such a transflective mode, a dual cell gap is applied to match the characteristics of the reflective part and the transparent part, but the problem of requiring high difficulty of the process as well as the light leakage problem of the stepped part is caused.

Accordingly, the present invention applies a single cell gap to a transflective liquid crystal display device. In particular, two common electrodes are integrated by patterning common electrodes on a second substrate so as to correspond to reflecting and transmissive portions formed on the first substrate. The purpose is to improve the above problems by forming an electrode and applying a common voltage to the common electrode individually.

And, achieving the above object can be further embodied through the present invention. That is, the transflective liquid crystal display according to the present invention comprises: a first substrate having a plurality of pixel regions divided into a reflecting portion and a transmitting portion; A reflector formed on a reflector of the first substrate; A pixel electrode formed in the pixel region of the first substrate on which the reflective plate is formed; A second substrate bonded to the first substrate; A black matrix formed on the second substrate at predetermined intervals; A unit color filter formed between the black matrices on the second substrate; An overcoat layer formed on the second substrate on which the black matrix and the unit color filter are formed; And a common electrode formed on the second substrate on which the overcoat layer is formed, and separated into two in correspondence with the reflecting portion and the transmitting portion formed on the first substrate, respectively, and separately driven by receiving a separate common voltage. It is characterized by.

In addition, the manufacturing method of the transflective liquid crystal display device according to the present invention comprises the steps of providing a first substrate; Providing a second substrate; Forming a black matrix on the second substrate; Forming a color filter between the black matrices on the second substrate; Forming an overcoat layer on the second substrate; Depositing a transparent electrode on the second substrate; Applying a photoresist on the second substrate; Exposing and developing the photomask on the second substrate; And etching a portion of the transparent electrode on the second substrate.

Then, with reference to the drawings with respect to the above configuration and manufacturing method will be described in detail. 2 is a perspective view of a first substrate and a second substrate of the transflective liquid crystal display device according to the present invention, in which R, G, B, and W are one dot. As shown in the drawing, the reflector F having the reflector 118 formed on the lower side corresponding to the pixel region P on the first substrate 111 and the transmissive part from which the conductive material of the reflector 118 is partially removed ( T) is formed. Further, on the second substrate 130, a color filter 133a formed between the black matrix 132 and the black matrix 132, an overcoat layer 134, a common electrode 135, and the like formed thereon are formed. .

FIG. 3 is a cross-sectional view of a W (white) unit pixel viewed along a cut plane I-I 'after bonding the first substrate 111 and the second substrate 131 of FIG. 2 according to the present invention. As shown in the figure, the thin film transistor formed on the lower first substrate 111 may include a gate electrode 112 to which a scan signal is applied, an active layer 114 to transmit a data signal in response to the scan signal, and A gate insulating film 113 that electrically isolates the active layer 114 and the gate electrode 112, a source electrode 116a formed on both sides of the active layer 114 to apply a data signal, and data; And a drain electrode 116b for applying a signal to the reflective electrode. In addition, a first protective film 117 and a second protective film 119 for protecting the thin film transistor including the source / drain electrodes 116a and 116b are additionally included. Of course, the first protective film 117 is included here. ) And a contact hole 119a and a first alignment layer 121 exposing the reflective plate 118 and the drain electrode 116b formed between the second protective layer 119 and the second passivation layer 119.

On the other hand, the color filter 133a formed on the second substrate 131 between the black matrix 132 formed corresponding to the thin film transistor and the black matrix 132 on the second substrate 131, and also the color filter. Two layers corresponding to the reflective part F and the transmission part T respectively formed on the first substrate 111 in correspondence with the overcoat layer 134 formed over the 133a and the pixel area on the first substrate 111. It is composed of an integrated common electrode 135. After that, of course, the second alignment layer 136 is formed.

FIG. 4 shows that the unit color filter formed on the second substrate 131 is composed of two common electrodes 135 integrated with the reflecting portion F and the transmitting portion T on the first substrate 111. Indicates. Accordingly, as can be seen in the drawing, the two common electrodes 135 have a first group of common electrodes and a first substrate, with the reflecting portions F on the first substrate 111 as a group. 111 and a common group of the corresponding second group are formed using the transmissive portions T on the 111 as a group, and the first common voltage Vcom1 is applied to the common group of the first group through silver (Ag) dots, In the second group of common electrodes, the second common voltage Vcom2 is separately applied in the same manner.

Herein, the common electrode 135 formed of two groups divides the common electrode 135 in correspondence with the reflecting portion F and the transmitting portion T on the first substrate 111, so that the common electrode 135 is separated from the outside. Of course, the individual voltage is driven by applying the common voltage of. In this regard, Korean Laid-Open Patent Publication No. 2006/0029366 exemplifies a circuit configuration capable of applying different common voltages to a common electrode. In this regard, applying an individual common voltage to a divided common electrode as in the present invention It will be more persuasive.

Now, a method of manufacturing a color filter substrate according to the present invention will be described in detail with reference to FIGS. 5A to 5E along the cut plane II-II ′ of FIG. 2. 5A shows a process of forming a black matrix. First, after cleaning the second substrate 130 such as a glass substrate, and deposited on the second substrate 131 by chromium / chromium oxide (Cr / CrOx) used as a black matrix material by sputtering, and then The Cr / CrOx layer is selectively patterned through an exposure and development process using a photolithography process technology to form a plurality of black matrices 132a and 132b having a predetermined space.

When the formation process of the above black matrix 132a and 132b is completed, each color filter is formed as shown in FIG. 5B. Although the drawing shows only the forming step of R for convenience, substantially R, G, and B And forming the color filters of W respectively. In detail, the first color pigment of R is applied on the black matrices 132a and 132b, and then a separate mask is applied to repeat the exposure and development processes to form the color filter 133a of R. Subsequently, G, B, and W color filters are formed in the same manner.

Subsequently, in order to protect and planarize the color filter 133a in the previous step, as shown in FIG. 5C, the overcoat layer 134 is formed using an acrylic resin or a polyimide resin. However, as will be appreciated, this process may be omitted when forming a black matrix that also serves as a column spacer in the initial process.

Then, the common electrode 135a is deposited on the entire surface of the second substrate 131, where the common electrode 135a has good permeability and conductivity, and has excellent chemical and thermal stability, such as indium tin oxide (ITO). Transparent metal materials are deposited by sputtering. Then, the photoresist 138 is applied to the entire surface of the second substrate 131 again, and exposure and development are performed by a photolithography process technology in which the mask 139 is applied. Of course, the common electrode portion to be etched later corresponds to the transmission region of the mask 139.

In addition, FIG. 5D forms two common electrodes which are integrated and separated, respectively, through an etching process. In other words, the formation may correspond to the reflection part F and the transmission part T formed on the first substrate 111. Of course, the second alignment layer 136 is formed on the common electrode 135, although not shown in the drawings.

Meanwhile, the method of forming color filters up to now depends on how the reflective part F and the transmissive part T are configured on the first substrate 111, and correspondingly, R, G, and the like on the second substrate 131. The configuration may also look slightly different depending on how the sub color filter is arranged to form a dot based on B and W, but the configuration and forming method become the same, so the scope of the present invention is such that It will extend to the W + transflective liquid crystal display including the area and a manufacturing method thereof.

As a result of the configuration up to now, the transflective liquid crystal display device according to the present invention, in applying a single cell gap, by separately patterning the common electrode corresponding to the reflection portion and the transmission portion formed on the first substrate so as to correspond to each of the common voltage Applying individually, this will solve the light leakage problem and the troublesome process that occurred in the dual gap.

Claims (4)

A first substrate having a plurality of pixel regions divided into a reflecting portion and a transmitting portion; A reflector formed on a reflector of the first substrate; A pixel electrode formed in the pixel region of the first substrate on which the reflective plate is formed; A second substrate bonded to the first substrate; A black matrix formed on the second substrate at predetermined intervals; A unit color filter formed between the black matrices on the second substrate; An overcoat layer formed on the second substrate on which the black matrix and the unit color filter are formed; And The transflective layer is formed on the second substrate on which the overcoat layer is formed, and is divided into two parts corresponding to each of the reflective part and the transmission part formed on the first substrate, and includes a common electrode separately driven by receiving a separate common voltage. LCD display device. The method of claim 1, wherein the first substrate A gate electrode formed on the first substrate; A gate insulating film formed on the first substrate on which the gate electrode is formed; A semiconductor layer formed on the gate electrode on which the gate insulating film is formed; Source and drain electrodes formed on the semiconductor layer; A first passivation layer formed on the first substrate on which the source and drain electrodes are formed; A reflector formed on a reflector on the first passivation layer; A second protective film formed on the first substrate on which the reflective plate shape is formed; And And a pixel electrode formed in the pixel region on the second passivation layer. The common electrode of claim 1, wherein the common electrode includes a single group of common electrodes of the first group corresponding to the reflective parts of the first substrate, and a single group of transmissive parts of the first substrate. A transflective liquid crystal display device comprising a second group of common electrodes. The method of claim 3, wherein the first common voltage is applied to the first group of common electrodes through silver (Ag) dots, and the second common voltage is applied to the second group of common electrodes through other silver dots. A semi-transmissive liquid crystal display device.

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