KR20050097227A - Ultra minimal roughness reflective layer for pixel designed thin film transistor and liquid crystal display - Google Patents

Abstract

The present invention relates to a thin film transistor and a liquid crystal display device having an ultra-fine rough reflection layer on the pixel unit. An ultrafine rough reflecting layer having an ultrafine rough surface is formed on the substrate. The ultrafine rough reflecting layer comprises an amorphous or partially crystalline indium-tin-oxide layer and a silicon containing rough layer to form an ultrafine rough surface. Subsequently, a reflective layer conforming to the shape of the rough layer is formed thereon to obtain an ultra fine rough reflective surface, thereby improving the reflection efficiency.

Description

Thin film transistors and liquid crystal displays designed with ultra-fine rough reflection layers for pixels {ULTRA MINIMAL ROUGHNESS REFLECTIVE LAYER FOR PIXEL DESIGNED THIN FILM TRANSISTOR AND LIQUID CRYSTAL DISPLAY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to flat panel displays, and more particularly, to reflective or transflective liquid crystal displays.

LCDs are widely used in electronic products such as digital clocks and calculators. In addition, with the development of manufacturing and design technology, thin film transistor liquid crystal display (TFT-LCD) has been applied to portable computers, personal digital assistants and color televisions, and is gradually replacing the conventional cathode ray tube display devices.

Currently, transmissive LCDs are mainly developed, and a light source generally called a back light of a transmissive LCD is located behind the display device. Therefore, a transparent conductive material such as indium tin oxide (ITO) is used as the pixel electrode. The backlight of the transmissive LCD consumes the most power. The most widely used fields of LCDs are portable computers and communication equipment, and batteries have been used as their main power supply means. Accordingly, reducing the power consumption of LCDs has become a major direction in the development of LCD products. When used in bright environments, the reflection of transmissive LCDs reduces contrast, resulting in blurry images.

In order to solve this problem, a reflective LCD has been developed. Since the light source of the reflective LCD is located outside the LCD, a reflective layer is needed to reflect the light. Usually, a pixel electrode is used as a reflection layer. As the pixel electrode, a reflective conductive material such as metal aluminum is used. The surface of the pixel electrode is not flat for better reflection. However, there still remains a problem that cannot be solved with reflective LCDs. That is, when the intensity of light from an external light source is not high enough, the reflective LCD cannot display a clear image. Thus, transflective LCDs are the goal of next-generation research and development. Since the pixel electrode of a reflective LCD is made of an aluminum plate filled with at least one opening, the backlight is turned on to serve as a light source when the external light intensity is not high enough.

Typically, the surface of the reflective layer consists of a discrete rough surface. The height difference of the rough surface is about 0.5 to 1.5 mu m. This height difference affects the arrangement of the liquid crystal molecules, resulting in poor image quality. 1 is a cross-sectional view of a conventional liquid crystal display (LCD). Referring to FIG. 1, the liquid crystal display includes an upper substrate 20 and a lower substrate 10. The liquid crystal layer is formed between the upper substrate 20 and the lower substrate 10. The reflective layer 12 made of resin is formed on the lower substrate 10. The difference in height at the surface of the reflective layer or rough layer 12 changes the cell gap. The cell gap in the protruding region 14 of the reflective layer 12 is smaller than the convex portion 16 of the rough layer 12. The reflection efficiency is related to the phase delay amount R of the liquid crystal cell, and the phase delay amount R of the liquid crystal cell is related to the change value? D of the cell gap and the birefringence index? N of the liquid crystal. The birefringence Δn of the liquid crystal is about 0.06 to 0.1. Therefore, if the change value Δd of the cell gap is 0.5 μm to 1.5 μm, the change value Δnd is 0.06 μm to 0.15 μm (that is, Δndj to Δndi).

The complete change in phase delay amount Δnd is the reflective twisted nematic mode (hereinafter referred to as RTN mode) and the mixed twisted nematic mode (hereinafter referred to as 'mixed mode'). In the case of 0.06m or less. This change value? Nd causes the reflection efficiency to reach 95% to 100% regardless of the twist angle value. However, the height difference existing in the conventional reflective layer enlarges the change value Δnd so that the reflection efficiency is lowered from the ideal value of 100% to 60%. This low reflection efficiency does not effectively reflect the ambient light to the user, making it impossible to display a clear image.

Therefore, the main object of the present invention is to use an ultrafine rough reflection layer in a liquid crystal display device. The ultra-fine rough reflection layer formed on the substrate may improve the reflection efficiency of the liquid crystal display device to 95% or more by reducing the change value of the phase delay amount.

Another object of the present invention is to provide an ultrafine rough reflecting layer that can be formed on any metal layer for a liquid crystal display. According to the present invention, the manufacturing process of the ultra-fine rough reflection layer is integrated into the manufacturing process of the thin film transistor. This integration not only optimizes the area of the ultrafine rough reflecting layer, but also reduces the manufacturing cost by reducing the use of photomasks.

Still another object of the present invention is to provide an ultrafine rough reflective layer made of an inorganic material for a liquid crystal display device. The reflective layer made of an inorganic material may be used at a higher temperature than the reflective layer made of an organic material. Therefore, the reflective layer is not deformed by the subsequent thermal process and the reflection efficiency is not affected.

It is still another object of the present invention to provide an ultrafine rough reflective layer for a liquid crystal display device. Both the amorphous indium-tin-oxide (ITO) layer and the silicon containing rough layer form a rough bottom layer with a rough surface. At this time, the reflective layer follows the shape of the rough lower layer having an ultrafine rough surface. The reflective layer also has an ultrafine rough surface. Thus, the ultrafine rough reflecting layer not only has an ultrafine convex-concave region but also improves the reflection angle of the reflected light.

In order to achieve the above object, the present invention provides an ultra-fine reflective layer structure. The ultrafine reflective layer structure is formed on a substrate of the liquid crystal display device to reflect ambient light. This structure consists of an amorphous or polycrystalline indium-tin-oxide layer, a silicon containing rough layer and a reflective layer. The amorphous indium-tin-oxide layer is formed over the substrate and the silicon containing rough layer is formed over the amorphous indium-tin-oxide layer. The silicon-containing rough layer has a rough surface. The height difference of a part of rough layer is 100 nm or less. The reflective layer is formed on the rough surface and follows the shape of the rough layer. Therefore, the ultrafine reflective surface is also formed on the reflective layer.

On the other hand, the present invention provides a structure of a thin film transistor liquid crystal display device. This structure is formed on a substrate and has a pair of gate conductive lines and a pair of source conductive lines. The gate conductive line pair is perpendicular to the source conductive line pair. The display device is formed between two pairs of conductive lines. Transistors are formed at edges of the display device and are connected to adjacent gate conductive lines and adjacent source conductive lines. The ultrafine reflective layer is formed in another area of the display device to reflect the ambient light. The height difference of some regions of the ultrafine rough surface is 100 nm or less.

The ultrafine reflecting layer according to the present invention has an ultrafine rough surface. The height difference in some regions of the ultrafine rough surface is 100 nm or less, which is much smaller than the height difference of the conventional reflective layer. The ultra-fine rough reflection layer effectively reduces the change in the amount of phase delay, thereby improving the reflection efficiency of the liquid crystal display device to 95% or more. In addition, the small grain of the rough surface increases the angle of the reflected light to extend the viewing angle. The reflective layer made of an inorganic material may be used at a higher temperature than the reflective layer made of an organic material. Therefore, the reflective layer is not deformed by the subsequent thermal process and the reflection efficiency is not affected.

 Other objects and features of the present invention in addition to the above object will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 2 to 8B.

The present invention provides a liquid crystal display having an ultra minimal reflective layer. The ultrafine reflective layer is composed of an amorphous indium-tin-oxide (a-ITO) and a rough layer containing silicon. An ultrafine rough surface is formed on this rough layer. Then, a reflective layer made of an inorganic material is formed on the rough layer, which reflects the shape of the rough layer. The reflective layer also has a very fine rough surface. The reflective layer made of an inorganic material may be used at a higher temperature than the reflective layer made of an organic material. On the other hand, the reflective layer having the fine rough surface not only has original reflection characteristics but also reduces the change in the cell gap, thereby improving the reflection efficiency of the liquid crystal display device to 95% or more. In particular, the manufacturing process of the reflective layer having the fine rough surface is integrated into the manufacturing process of the conventional thin film transistor, thereby reducing the use of the photomask in the manufacturing process. Accordingly, the present invention can reduce the manufacturing cost.

Reflective layers having a fine rough surface according to the present invention are used in liquid crystal display devices, in particular in reflective or transflective liquid crystal display devices. The structure proposed in the present invention is illustrated as one preferred embodiment without limiting the technical spirit and scope of the present invention. Those skilled in the art will be able to apply the present invention to various kinds of liquid crystal display devices through the embodiments of the present invention. The application of the present invention is not limited to the examples as follows.

The manufacturing process of the reflecting layer which has a fine rough layer is demonstrated. 2A and 2B are schematic cross-sectional views of an ultrafine reflective layer in accordance with a preferred embodiment of the present invention. Referring to FIG. 2A, a substrate 100 is provided. The substrate 100 is a glass substrate used for a liquid crystal display device.

First, an amorphous indium-tin-oxide layer (a-ITO) 210 is formed on the substrate 100. In addition, a polycrystalline indium-tin-oxide layer may be used. The amorphous indium-tin-oxide layer is formed by a CVD process such as plasma growth CVD using indium oxide and tin oxide. The indium tin oxide layer is controlled to form an amorphous crystal structure by the conditions in the process.

Next, a silicon-containing rough layer 220 is formed on the a-ITO layer 210. The silicon-containing rough layer 220 is made of amorphous silicon, polysilicon, silicon nitride (SiN _x ), silicon oxide (SiO _x ), or silicon oxynitride (SiON _x ). Typically, the silicon-containing rough layer 220 is formed by a CVD process. The crystal structure of the a-ITO layer 210 extends into the silicon-containing rough layer 220 to become a silicon-containing rough layer 220 having a very fine rough surface 222. It is very important to adjust the level of roughness of the ultrafine rough surface 222 while forming the silicon-containing rough layer 220. The size of the protruding grains on the ultrafine rough surface 222 of the silicon containing rough layer 220 is controlled by changing the process conditions. As shown in Fig. 2A, the average length L of the protruding grains is about 10 nm to 800 nm and the height H is about 5 nm to 100 nm. The acute angle α of the protruding grains is adjusted within approximately 1 to 60 degrees.

Referring to FIG. 2B, a reflective layer 230 is formed on the silicon-containing rough layer 220. The a-ITO layer 210, the silicon-containing rough layer 220, and the reflective layer 230 constitute the ultrafine reflective layer 200. The reflective layer 230 is formed of a material having excellent reflective properties. In general, the reflective layer 230 is formed of a metal material such as aluminum (Al), silver (Ag), or a composition thereof. The reflective layer 230 follows the shape of the silicon-containing rough layer 220. Thus, an ultrafine rough surface, which is the same as that of the silicon containing rough layer 220, is formed over the reflective layer 230. The acute angle of the protruding grains of the ultrafine rough surface of the reflective layer 230 is adjusted to approximately 1 to 60 degrees, and the preferred acute angle is approximately 3 to 20 degrees. Good reflection efficiency is obtained in this acute angle range.

As shown in FIG. 3, a bump layer 110 is formed between the substrate 100 and the ultrafine reflective layer 200. The bump layer 110 is formed of a metal material such as aluminum (Al), chromium (Cr), and MoCr. Alternatively, inorganic materials such as silicon nitride or silicon oxide and organic materials such as resins and photoresists may be used to form the bump layer. For example, when the bump layer 110 is made of MoCr, an aluminum layer is first formed over the MoCr layer, and then a photoresist layer having bumps over the aluminum layer is formed. Wet etching is used to etch the photoresist and MoCr layers to form slanted metal bumps. The height difference of the bump layer 110 is adjusted to about 30 to 1600nm. The inclination angle of the bump layer 110 is adjusted to about 2 to 75 degrees. The bump layer 110 controls the reflection efficiency in a specific direction. In addition, the bump layer 110 has a large dispersion angle. Accordingly, the bump layer 110 evens the reflection efficiency to avoid a sudden change in the reflection efficiency according to the viewing angle. In other words, the bump layer 110 has a function of preventing sparking.

In addition, the bump layer 110 may be formed of a resin. An ultrafine reflective layer 200 is formed on the bump layer 110. When the resin is used to form the bump layer 110, a sparking prevention function can be obtained. Both the bump layer 110 and the ultrafine reflective layer 220 are made of a material that can withstand high temperatures. The process is performed at a temperature of about 400 to 500 degrees with respect to the bump layer 110 and the ultrafine reflective layer 200. This type of high temperature process does not deform the bump layer 110 and the ultrafine reflective layer 200. Thus, the present invention provides a stable structure that can avoid the effects of subsequent processes.

The bump layer 110 has at least two designs. In a first design, the transmissive region is distributed over most of the bump layer 110. The reflective area is then patterned in the transmissive area. The pattern of the reflection area consists of a round pattern of discrete distribution. Subsequently, the bump layer 110 and the ultrafine reflective layer 200 are formed using the technique described above. In a second design, the reflective area is distributed over most of the bump layer 110. Then, the transmission area is patterned in the reflection area. The pattern of transmissive regions consists of a round pattern of discrete distribution. However, other types of patterns such as rectangular patterns of discrete distributions, elliptical patterns of discrete distributions, and the like may be used as the transmission area pattern. Subsequently, the bump layer 110 and the ultrafine reflective layer 200 are formed using the technique as described above. Reflective areas are formed according to a discrete round pattern.

4 is a view comparing the change value Δnd of the reflection efficiency and the phase delay amount with respect to the reflective layer according to the present invention and the prior art. The conventional reflective layer has a sharp change in cell gap. Due to the drastic change in the cell gap, the reflection efficiency is reduced. In addition, the small twist angle of the liquid crystal molecules causes low reflection efficiency. On the other hand, the ultrafine reflective layer of the present invention evens out abrupt changes in the cell gap. Therefore, the liquid crystal display device can maintain a high reflection efficiency of approximately 90% regardless of the magnitude of the twist angle of the liquid crystal. The liquid crystal molecules used in the structure of the present invention are positive liquid crystal molecules. Usually, the birefringence Δn of the liquid crystal is about 0.055 to 0.12, the amount of phase delay R Δn × d _T is about 260 nm to 345 nm and the amount of phase delay R Δn × d _R is about 205 nm to 345 nm. Alternatively, the liquid crystal molecules used in the structure of the present invention may be negative liquid crystal molecules. Usually, the birefringence Δn of the liquid crystal is about 0.055 to 0.135, the phase delay amount (R) Δn × d _T is about 325 nm to 510 nm and the phase delay amount (R) Δn × d _R is about 205 nm to 345 nm.

The ultrafine reflecting layer according to the present invention can be used for any kind of thin film transistor, and the manufacturing process of the ultrafine reflecting layer can be integrated into the manufacturing process of the thin film transistor. The manufacturing process of the amorphous thin film transistor will be described later. In addition, the manufacturing process of the ultra-fine reflecting layer according to the present invention may be integrated into the manufacturing process of other devices such as polysilicon thin film transistor having a structure similar to the thin film transistor. Meanwhile, the amorphous silicon thin film transistor may have various other types of structures. For example, a storage capacitor may be formed on the common electrode or the gate electrode. The technique described below relates to an amorphous silicon thin film transistor in which a storage capacitor is formed on a common electrode. However, the same technique may be applied to the amorphous silicon thin film transistor in which the storage capacitor is formed on the gate electrode. Similarly, the technique described below is applied to the N-type thin film transistor, but may be applied to the P-type thin film transistor or the complementary thin film transistor.

An ultrafine reflective layer having a high reflection efficiency is disposed between any two layers to form a common layer having a metal conductive layer. Hereinafter, each embodiment of the present invention will be described.

[First Embodiment]

First, an ultrafine reflective layer is formed on the lower layer so that a common layer having the first metal conductive line layer according to the first embodiment is formed. 5A is a schematic plan view of an ultrafine reflective layer and a first conductive line layer according to a first embodiment of the present invention. FIG. 5B is a schematic cross-sectional view of the ultrafine reflective layer and the first conductive line layer cut along the line I-I of FIG. 5A according to the first embodiment of the present invention. 5A and 5B, first, a gate conductive line 510a connected to the gate electrode 510 and the gate electrode 510 is formed on the substrate 500 when the thin film transistor is manufactured. During the manufacture of the gate electrode 510, the storage capacitor 700 is formed at a position corresponding to the gate electrode 510. An ultrafine reflective layer 600 is disposed between the storage capacitor 700 and the gate electrode line 510a. The manufacturing process of the ultrafine reflective layer 600 is as described above. In the manufacture of the ultra-micro reflective layer 600, a specific gap must exist to avoid the generation of a coupled capacitor between the storage capacitor 700 and the gate electrode line 510a. After completion of the process, a first dielectric layer 512 is formed over the entire substrate 500. This first dielectric layer 512 is incorporated into the rough layer of the ultrafine reflective layer 600 (ie, silicon containing rough layer 220). This integration eliminates the need for a photomask process.

Next, forming a source electrode and a drain electrode is performed. An amorphous silicon layer 514 is formed at a position corresponding to the gate electrode 510. Subsequently, two doped polysilicon layers 516 are formed symmetrically around the amorphous silicon layer 514. The second metal conductive line is manufactured in the following process. First, metal layers are formed on the two doped polysilicon layers 516 to form vertical conductive lines connected to the drain electrode 518, the source electrode 520, and the source electrode 520. A second dielectric layer having a contact window 530 is formed on the drain electrode 518, the source electrode 520, the amorphous silicon layer 514, and the first dielectric layer 512. Finally, the transparent electrode 540 is formed in the region where the transistor is not present. The transparent electrode 540 is made of indium tin oxide (ITO). The transparent electrode 540 is connected to the drain electrode 518 through the contact window 530. In the case of a display device having a size of 700 × 210 μm, the aperture ratio of the ultrafine reflective layer 600 to the display device is approximately 75% due to the storage capacitor 700. If the storage capacitor 700 is formed near the gate electrode, the aperture ratio of the ultrafine reflective layer 600 to the display device may be increased to about 80%. A bump layer may be formed under the ultrafine reflective layer to improve the glare prevention function.

Second Embodiment

The ultrafine reflecting layer according to the present invention is formed in the second layer in addition to the lower layer, thereby forming a common layer having a conductive line located in the second layer. 6A is a schematic plan view of an ultrafine reflective layer and a second metal conductive line layer according to a second embodiment of the present invention. FIG. 6B is a schematic cross-sectional view of the ultrafine reflective layer and the second conductive line layer cut along the line II-II of FIG. 6A according to the second embodiment of the present invention. 6A and 6B, first, a gate conductive line 510a connected to the gate electrode 510 and the gate electrode 510 is formed on the substrate 500 when the thin film transistor is manufactured. During the manufacture of the gate electrode 510, the storage capacitor 700 is formed at a position corresponding to the gate electrode 510. The first dielectric layer 512 is formed over the entire substrate 500. This first dielectric layer 512 is integrated into the rough layer of the ultrafine reflective layer 610 (ie, silicon containing rough layer 220). This integration eliminates the need for a photomask process.

Next, forming a source electrode and a drain electrode is performed. An amorphous silicon layer 514 is formed in the gate electrode 510. Subsequently, two doped polysilicon layers 516 are formed symmetrically around the amorphous silicon layer 514, such as an N-doped polysilicon layer. The second metal conductive line is manufactured in the following process. First, metal layers are formed on the two doped polysilicon layers 516 to form vertical conductive lines connected to the drain electrode 518 (shown in FIG. 5A), the source electrode 520, and the source electrode 520. Finally, an ultrafine reflective layer 610 is formed in the display device formed between the two conductive lines 510a and the conductive lines connected to the source electrode 520. The manufacturing method is the same as the manufacturing method of the ultra-fine reflecting layer 200 described above. The drain electrode 518 is directly coupled with the ultrafine reflective layer 610 to extend the reflective region as shown in FIG. 6A. This isolation design has desirable electrical properties.

Next, a second dielectric layer 522 having a contact window 530 is formed on the drain electrode 518, the source electrode 520, the amorphous silicon layer 514, and the ultrafine reflective layer 610. Finally, the transparent electrode 540 is formed in the region where the transistor is not present. The transparent electrode 540 is made of indium tin oxide (ITO). The transparent electrode 540 is connected to the drain electrode 518 through the contact window 530. The ultrafine reflective layer 610 is located in the second conductive line layer and thus is not affected by the storage capacitor. However, a gap must still exist in the vertical conductive line connected to the source electrode to avoid generation of the coupling capacitor. In the case of a display device having a size of 700 × 210 μm, the aperture ratio of the ultrafine reflective layer 610 to the display device is approximately 80% due to the gap. A bump layer may be formed under the ultrafine reflective layer to improve the glare prevention function.

Third Embodiment

The ultrafine reflective layer according to the present invention is formed in the third layer, thereby forming a common layer having a transparent electrode named E in the third embodiment of the present invention. 7A is a schematic plan view of an ultrafine reflective layer and a third metal conductive line layer according to a third embodiment of the present invention. FIG. 7B is a schematic cross-sectional view of the ultrafine microreflective layer and the third conductive line layer cut along the line III-III of FIG. 7A according to the third embodiment of the present invention. 7A and 7B, first, a gate conductive line 510a connected to the gate electrode 510 and the gate electrode 510 is formed on the substrate 500 when the thin film transistor is manufactured. During the manufacture of the gate electrode 510, the storage capacitor 700 is formed at a position corresponding to the gate electrode 510. After completion of the process, a first dielectric layer 512 is formed over the entire substrate 500.

Next, a source electrode and a drain electrode are formed. An amorphous silicon layer 514 is formed at a position corresponding to the gate electrode 510. Subsequently, two doped polysilicon layers 516 are formed symmetrically around the amorphous silicon layer 514, such as an N-doped polysilicon layer. The second metal conductive line is manufactured by the following process. First, metal layers are formed on the two doped polysilicon layers 516 to form vertical conductive lines connected to the drain electrode 518, the source electrode 520, and the source electrode 520. A second dielectric layer 522 having a contact window 530 is formed on the drain electrode 518, the source electrode 520, the amorphous silicon layer 514, and the first dielectric layer 512. Finally, the transparent electrode 540 is formed in the region where the transistor is not present. The transparent electrode 540 is made of indium tin oxide (ITO). The transparent electrode 540 is connected to the drain electrode 518 through the contact window 530. Finally, an ultrafine reflective layer 620 is formed in the display device formed between the two gate conductive lines 510a and the conductive lines connected to the source electrode 520. The manufacturing method is the same as the manufacturing method of the ultra-fine reflecting layer 200 described above.

The lower layer of the ultrafine reflective layer 620 is combined with the transparent electrode 540 to form an a-ITO layer. This manufacturing method eliminates the need for the processing steps of the transparent electrode 540. However, the metal reflective layer (corresponding to the reflective layer 230) should be connected to the drain electrode 518 to serve as a display electrode. In addition, a rough layer of ultrafine reflective layer 620 (ie, silicon containing rough layer 220) may be used to remove dielectric layer 522 and replace dielectric layer 522. The ultrafine reflective layer 620 is located in the upper conductive line layer and thus is not affected by the first conductive line layer and the second conductive layer. The ultrafine reflective layer 620 occupies a maximum area according to the above-described structure.

In the case of a display device having a size of 700 × 210 μm, the aperture ratio of the ultrafine reflective layer 620 to the display device is approximately 88% because the boundary of the ultrafine reflective layer 620 is aligned with the conductive line around the reflective layer 620. do. If the ultrafine reflective layer 620 is formed in the third conductive line layer, the desired process integration can be achieved because the interference from the peripheral conductive line is reduced. In addition, if the upper layer of the ultrafine reflective layer 620 is made of a conductive material, the upper layer may be used to replace the conventional ITO layer with an opening electrode.

[Example 4]

The above three embodiments relate to a reflective liquid crystal display device. The ultrafine reflective layer can also be used in a transflective liquid crystal display device. In the fourth embodiment, the ultrafine reflecting layer according to the present invention is used in the transflective liquid crystal display, and the ultrafine reflecting layer is formed in the second layer to form a common layer having the conductive lines located in the second layer. 8A is a schematic plan view of an ultrafine reflective layer used in a transflective liquid crystal display according to a fourth embodiment of the present invention. FIG. 8B is a schematic cross-sectional view cut along the line IV-IV of FIG. 8A. FIG. 8A and 8B, a gate conductive line 510a connected to the gate electrode 510 and the gate electrode 510 is first formed on the substrate 500 in a process similar to that of the second embodiment in manufacturing the thin film transistor. . During the manufacture of the gate electrode 510, the storage capacitor 700 is formed at a position corresponding to the gate electrode 510. The first dielectric layer 512 is formed over the entire substrate 500.

Next, a source electrode and a drain electrode are formed. An amorphous silicon layer and a doped polysilicon layer are sequentially formed over the first dielectric layer 512. The second metal conductive line is formed by the following process. First, a metal layer is formed on the doped polysilicon layer 516 to form a vertical conductive line 520a connected to the drain electrode 518 (shown in FIG. 5A), the source electrode 520, and the source electrode 520, respectively. . Finally, an ultrafine reflective layer 610a is formed in the display device formed between the two gate metal lines 510a and the conductive line 520a connected to the source electrode. The manufacturing method is the same as the manufacturing method of the ultra-fine reflecting layer 200 described above. The drain electrode 518 is directly coupled with the ultrafine reflective layer 610a to extend the reflective region as shown in FIG. 8A.

In this design method, a specific gap exists between the ultrafine reflective layer 610a and the gate electrode line 510a. Further, there is another specific gap between the ultrafine reflective layer 610a and the vertical source electrode conductive line 520a. The reflective region R (ie, the ultrafine reflective layer) is located at the center and surrounded by the transmission region T. Ambient light is reflected by the ultrafine reflective layer 610a to form the reflected light L _R. The back light passes through the transmission region _T to form transmitted light L _T. The ratio of the transmitted light L _T to the reflected light L _R can be modified according to the switching operation of the light source. In addition, the ratio of the transmission area to the reflection area can be modified by adjusting the area of the ultrafine reflection layer 610a.

As described above, a transmission pattern is designed on the ultrafine reflection layer 610a to form a transmission region. The transmission pattern consists of a round pattern of discrete distributions, a rectangular pattern of discrete distributions, an oval pattern of discrete distributions, and the like. The transmission region and the reflection region each have a first region and a second region. The ratio of the first region to the second region is approximately 10% to 420%. The transmission efficiency can be modified by adjusting the ratio of the first region to the second region.

The electrode openings formed in the upper electrode and the lower electrode form a multi-domain structure by appropriately disposing a vertical alignment form with the negative liquid crystal to exhibit an electric field effect.

In the structure described above, a cover layer is not formed on the thin film transistor. Thus, a black matrix can be used as the cover layer to avoid unnecessary reflected light.

According to the above-described preferred embodiment, the ultra-fine reflecting layer can be used in a reflective or semi-transmissive liquid crystal display device such as TFT-LCD, poly-Si TFT-LCD, STN-LCD, TFD-LCD and the like.

As described above, according to the present invention, the reflection efficiency may be improved by the microfine reflective layer. In addition, the reflective layer having ultra fine grains reduces the height difference of its surface to avoid sudden changes in the cell gap, thereby improving the reflection efficiency. Meanwhile, the reflective layer made of an inorganic material may be used at a higher temperature than the reflective layer made of an organic material. Therefore, the reflective layer is not deformed or influenced by the reflection efficiency by the subsequent thermal process. In addition, a bump layer may be used for the structure. The bump layer has a large dispersion angle. Therefore, it is possible to improve the anti-glare function by making the reflection efficiency even so as to avoid a sudden change in the reflection efficiency according to the viewing angle.

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.

1 is a schematic cross-sectional view of a conventional liquid crystal display device in which a rough surface having a large height difference is formed on a glass substrate and its reflection efficiency is lowered due to the large height difference.

2A and 2B are schematic cross-sectional views of an ultrafine reflective layer in accordance with one embodiment of the present invention.

3 is a schematic cross-sectional view of an ultrafine reflective layer in accordance with another embodiment of the present invention.

4 is a diagram comparing the change value Δnd of the reflection efficiency and the phase delay amount with respect to the reflective layer according to the present invention and the related art.

5A is a schematic plan view of an ultrafine reflective layer and a first metal layer according to the present invention.

5B is a schematic cross-sectional view of an ultrafine reflective layer and a first metal layer in accordance with the present invention.

6A is a schematic plan view of an ultrafine reflective layer and a second metal layer in accordance with the present invention.

6B is a schematic cross-sectional view of an ultrafine reflective layer and a second metal layer in accordance with the present invention.

7A is a schematic plan view of an ultrafine reflective layer and a third metal layer in accordance with the present invention.

7B is a schematic cross sectional view of an ultrafine reflective layer and a third metal layer in accordance with the present invention.

8A is a schematic plan view of an ultrafine reflective layer formed in a transflective liquid crystal display according to the present invention.

8B is a schematic cross-sectional view of an ultrafine reflective layer formed in a transflective liquid crystal display according to the present invention.

Claims (50)

Formed in a pixel unit of a liquid crystal display for reflecting ambient light, the liquid crystal device having a first substrate, a second substrate, and a liquid crystal layer formed between the first substrate and the second substrate, wherein the pixel unit is a transmission region. And an ultrafine reflective layer structure configured to have a reflective region, An amorphous indium-tin-oxide layer located on the first substrate; A silicon-containing rough layer on the amorphous indium-tin-oxide and having an ultrafine rough surface having a height difference of 10 nm or less in the region; And a reflective layer on the silicon-containing rough layer and having a surface identical to that of the ultra-fine rough surface in accordance with the shape of the silicon-containing rough layer. The method of claim 1, The structure is an ultra-fine reflecting layer structure, characterized in that used as a TFT-LCD, a-Si TFT-LCD, poly-Si TFT-LCD, STN-LCD or TFD-LCD to be a reflective layer. The method of claim 1, And the material of the silicon-containing rough layer is selected from silicon nitride, silicon oxide and silicon oxynitride. The method of claim 1, The ultrafine rough reflecting surface structure of the ultrafine reflecting layer, characterized in that it comprises a plurality of protruding regions. The method of claim 4, wherein Ultrafine micro reflective layer structure, characterized in that the acute angle of the ultra-fine rough surface is 1 to 60 degrees. The method of claim 1, The material of the reflective layer is an ultrafine reflective layer structure, characterized in that consisting of a metal or multiple layers with a high reflection efficiency. The method of claim 1, The material of the reflective layer is an ultrafine reflective layer structure, characterized in that selected from aluminum (Al), silver (Ag) and compositions thereof. The method of claim 1, And a bump layer disposed between the first substrate and the amorphous indium-tin-oxide layer and having a height difference of 30 to 1600 nm between the surfaces thereof. The method of claim 8, Ultra-fine micro reflective layer structure, characterized in that the acute angle of the bump layer surface is 2 to 75. The method of claim 8, The material of the bump layer is ultra-fine reflective layer structure, characterized in that selected from metal materials, inorganic materials or organic materials. The method of claim 8, The material of the bump layer is ultra-fine reflective layer structure, characterized in that selected from aluminum (Al), chromium (Cr), MoCr, silicon nitride or silicon oxide. The method of claim 8, The material of the bump layer is an ultrafine reflective layer structure, characterized in that the resin or an organic photoresist. The method of claim 1, The liquid crystal is characterized in that the positive type having 0.055 to 0.12 in birefringence index Δn, 260nm to 450nm of the phase delay amount (R) Δn × d _T, and 205nm to 345nm phase delay amount _(R) Δn × d R of the liquid crystal An ultrafine reflective layer structure. The method of claim 1, The liquid crystal is a negative type liquid crystal having a birefringence Δn of 0.055 to 0.135, a phase delay amount (R) Δn × d _T of 325 nm to 510 nm, and a phase delay amount (R) Δn × d _R of 150 nm to 410 nm. An ultrafine reflective layer structure. The method of claim 1, And the transmissive region has a first spacing between cells and the reflective region has a second spacing between cells, and the distance between the first and the second spacing is less than 0.6 μm. The method of claim 1, And wherein said transmissive region has a first region and said reflective region has a second region, wherein a ratio of said first region to said second region is between 10% and 420%. The method of claim 1, The ultrafine reflecting layer structure, characterized in that the pattern of the transmission region is a round pattern, rectangular pattern or elliptical pattern. Formed in a pixel unit of a liquid crystal display for reflecting ambient light, the liquid crystal device having a first substrate, a second substrate, and a liquid crystal layer formed between the first substrate and the second substrate, wherein the pixel unit is a transmission region. And a method for forming an ultrafine reflective layer adapted to have a reflective region, Forming an amorphous indium-tin-oxide layer overlying the first substrate; Forming a silicon-containing rough layer having an ultrafine rough surface having a height difference in the region of 10 nm or less on the amorphous indium-tin-oxide; And forming a reflective layer on the silicon-containing rough layer, the reflective layer having a same surface as the ultra-fine rough surface in accordance with the shape of the silicon-containing rough layer. The method of claim 18, The amorphous indium-tin-oxide layer is formed by a CVD method. The method of claim 18, And the amorphous indium tin oxide layer is formed by PECVD. The method of claim 18, And the material of the silicon-containing rough layer is selected from silicon nitride, silicon oxide and silicon oxynitride. The method of claim 18, Acute angle of the ultra-fine rough surface is an ultra-fine reflective layer forming method, characterized in that 1 to 60 degrees. The method of claim 18, The material of the reflective layer is an ultrafine reflective layer forming method, characterized in that made of a metal or multiple layers having a high reflection efficiency. The method of claim 18, The material of the reflective layer is selected from aluminum (Al), silver (Ag), and compositions thereof. The method of claim 18, And forming a bump layer between the first substrate and the amorphous indium-tin-oxide layer, the bump layer having a height difference of 30 to 1600 nm between the surface of the first substrate and the amorphous indium-tin-oxide layer. The method of claim 25, The acute angle of the bump layer surface is 2 to 75, characterized in that the ultra-fine reflective layer forming method. The method of claim 25, The material of the bump layer is an ultrafine reflective layer forming method, characterized in that selected from a metallic material, an inorganic material or an organic material. The method of claim 25, And the material of the bump layer is selected from aluminum (Al), chromium (Cr), MoCr, silicon nitride or silicon oxide. The method of claim 25, The bump layer is formed of a resin or an organic photoresist. The method of claim 18, The liquid crystal is characterized in that the positive type having 0.055 to 0.12 in birefringence index Δn, 260nm to 450nm of the phase delay amount (R) Δn × d _T, and 205nm to 345nm phase delay amount _(R) Δn × d R of the liquid crystal Ultrafine micro reflective layer forming method. The method of claim 18, The liquid crystal is a negative type liquid crystal having a birefringence Δn of 0.055 to 0.135, a phase delay amount (R) Δn × d _T of 325 nm to 510 nm, and a phase delay amount (R) Δn × d _R of 150 nm to 410 nm. Ultrafine micro reflective layer forming method. The method of claim 1, And wherein the transmissive region has a first spacing between cells and the reflective region has a second spacing between cells, and the distance between the first and the second spacing is less than or equal to 0.6 μm. The method of claim 1, Wherein said transmissive region has a first region and said reflective region has a second region, and wherein the ratio of said first region to said second region is between 10% and 420%. The method of claim 18, The pattern of the transmissive region is an ultrafine reflective layer forming method, characterized in that the round pattern, rectangular pattern or elliptical pattern. A pixel unit structure of a liquid crystal display device having a first substrate, a second substrate, and a liquid crystal layer formed between the first substrate and the second substrate and positioned on the first substrate, A pair of gate electrode conductive lines disposed parallel to each other; A pair of source electrode conductive lines disposed parallel to each other and perpendicular to the pair of gate electrode conductive lines, and a display device formed between the gate electrode conductive line and the source electrode conductive line; A transistor positioned at an edge of the display device and connected to the adjacent gate electrode conductive line and the adjacent source electrode conductive line; And an ultrafine reflecting layer positioned on said display for reflecting ambient light and having an ultrafine rough surface. 36. The method of claim 35 wherein And the ultra-fine reflective layer is formed of an amorphous indium-tin-oxide (ITO) layer. 36. The method of claim 35 wherein And the material of the silicon-containing rough layer is selected from silicon nitride, silicon oxide and silicon oxynitride. 36. The method of claim 35 wherein The acute angle of the ultrafine rough surface is 1 to 60 degrees, the pixel unit structure of the liquid crystal display device. 36. The method of claim 35 wherein The material of the reflective layer is a pixel unit structure of a liquid crystal display device, characterized in that made of a metal or multiple layers having a high reflection efficiency. 36. The method of claim 35 wherein The material of the reflective layer is selected from aluminum (Al), silver (Ag) and compositions thereof. 36. The method of claim 35 wherein And a bump layer disposed between the first substrate and the amorphous indium-tin-oxide layer, the bump layer having a height difference of 30 to 1600 nm between the surface of the first substrate and the amorphous indium-tin-oxide layer. The method of claim 41, wherein The acute angle of the bump layer surface is 2 to 75, the pixel unit structure of the liquid crystal display device. The method of claim 41, wherein The material of the bump layer is a pixel unit structure of the liquid crystal display device, characterized in that selected from a metallic material, an inorganic material or an organic material. The method of claim 41, wherein And the material of the bump layer is selected from aluminum (Al), chromium (Cr), MoCr, silicon nitride, or silicon oxide. The method of claim 41, wherein The material of the bump layer is a pixel unit structure of a liquid crystal display device, characterized in that the resin or an organic photoresist. 36. The method of claim 35 wherein The liquid crystal is characterized in that the positive type having 0.055 to 0.12 in birefringence index Δn, 260nm to 450nm of the phase delay amount (R) Δn × d _T, and 205nm to 345nm phase delay amount _(R) Δn × d R of the liquid crystal A pixel unit structure of a liquid crystal display device. 36. The method of claim 35 wherein The liquid crystal is a negative type liquid crystal having a birefringence Δn of 0.055 to 0.135, a phase delay amount Δn × d _T of 325 nm to 510 nm, and a phase delay amount R of Δn × d _R of 150 nm to 410 nm. A pixel unit structure of a liquid crystal display device. The method of claim 1, Wherein the transmissive region has a first spacing between cells and the reflective region has a second spacing between cells, and a distance between the first and the second spacing is 0.6 μm or less. Structure. 36. The method of claim 35 wherein And wherein the transmissive region has a first region and the reflective region has a second region, and the ratio of the first region to the second region is 10% to 420%. 36. The method of claim 35 wherein And the pattern of the transmissive region is a round pattern, a rectangular pattern or an elliptical pattern.