KR20030058787A - Reflector structure of liquid crystal display and fabricating method thereof - Google Patents

Abstract

PURPOSE: A reflective plate structure of a liquid crystal display and a method for manufacturing the same are provided to maximize a valid reflective area and an incline area, thereby improving the reflective efficiency. CONSTITUTION: A reflective plate(200) is formed on a substrate. A photosensitive film is formed on the reflective plate. The photosensitive film is exposed and developed to form patterns of the photosensitive film with pyramid type protrusions(203) having line widths and distances in the range of 0.5 μm- 5μm. The pyramid type protrusions are defined by crossing horizontal grooves(201) with vertical grooves(202). The reflective plate is etched through the patterns of the photosensitive film to transfer winding forms according to the patterns of the photosensitive film to the reflective plate. The residual patterns of the photosensitive film are removed.

Description

Reflector plate structure of liquid crystal display and manufacturing method therefor {REFLECTOR STRUCTURE OF LIQUID CRYSTAL DISPLAY AND FABRICATING METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective plate structure of a liquid crystal display device and a manufacturing method thereof, and more particularly, to a reflective plate structure of a liquid crystal display device and a method of manufacturing the same, which are suitable for improving the reflection efficiency of a reflective plate applied to a liquid crystal display device.

In general, a liquid crystal display device displays a desired image by individually supplying data signals according to image information to liquid crystal cells arranged in a matrix form, and adjusting a light transmittance of the liquid crystal cells. to be.

Accordingly, a liquid crystal display device includes: a liquid crystal panel in which liquid crystal cells forming a pixel unit are arranged in a matrix form; A driver integrated circuit (IC) for driving the liquid crystal cells is provided.

The liquid crystal panel is provided with a liquid crystal layer in which the thin film transistor array substrate and the color filter substrate are uniformly spaced apart from each other, and the liquid crystal is filled between the thin film transistor array substrate and the color filter substrate.

On the thin film transistor array substrate of the liquid crystal panel, a plurality of data wires for transmitting the data signal supplied from the data driver integrated circuit to the liquid crystal cells and a scan signal supplied from the gate driver integrated circuit for the liquid crystal cells are provided. A plurality of gate lines are orthogonal to each other, and liquid crystal cells are defined at each intersection of these data lines and the gate lines.

In this case, the gate driver integrated circuit sequentially supplies scan signals to a plurality of gate lines so that the liquid crystal cells arranged in a matrix form are sequentially selected one by one, and a data driver is provided in the selected one line of liquid crystal cells. The data signal is supplied from the integrated circuit.

Meanwhile, a common electrode and a pixel electrode are formed on opposite inner surfaces of the thin film transistor array substrate and the color filter substrate to apply an electric field to the liquid crystal layer. In this case, the pixel electrode is formed for each liquid crystal cell on the thin film transistor array substrate, while the common electrode is integrally formed on the entire surface of the color filter substrate. Therefore, by controlling the voltage applied to the pixel electrode in a state where a voltage is applied to the common electrode, it is possible to individually control the light transmittance of the liquid crystal cells.

As described above, in order to control the voltage applied to the pixel electrode for each liquid crystal cell, a thin film transistor used as a switching element is formed in each liquid crystal cell.

In liquid crystal cells in which a scan signal is supplied to a gate electrode of the thin film transistor through a gate wiring, a conductive channel is formed between the source electrode and the drain electrode of the thin film transistor, and thus is supplied to the source electrode of the thin film transistor through the data wiring. The data signal is supplied to the pixel electrode via the drain electrode of the thin film transistor. Accordingly, by selectively switching the thin film transistors to supply or cut off the voltage value of the data signal according to the image information for each liquid crystal cell, it is possible to control the light transmission of the liquid crystal cell.

As described above, a general liquid crystal display device does not emit light by itself and has a characteristic of displaying an image by adjusting light transmittance, so that a separate light source such as a back light or external natural light is required.

A liquid crystal display device using the backlight as a light source is generally a transmissive type, and a liquid crystal display device using external natural light as a light source is called a reflection type.

The transmissive liquid crystal display device is divided into a direct method in which a backlight is disposed on a bottom surface of the liquid crystal panel and an edge method disposed in one side or both sides of the liquid crystal panel. Currently, an edge method is mainly used.

However, the transmissive liquid crystal display is a very inefficient optical modulator in which only 3% to 8% of the light incident by the backlight is transmitted.

That is, assuming that the transmittance of the two polarizing plates is about 45%, that of the two glass substrates facing each other is about 94%, the thin film transistor array and the pixel transmittance are about 65%, and the color filter transmittance is about 27%. The total transmittance of the display device is about 7.4%.

As described above, since the amount of light actually penetrating the liquid crystal display is about 7% of the light incident by the backlight, in the case of the liquid crystal display which requires high brightness, the backlight should be very bright, resulting in large power consumption. .

Therefore, in order to supply sufficient power to the backlight, a large capacity of the power supply device has been designed and a large capacity battery which has a heavy weight has been used.

However, even when the battery of the large capacity is used, it is restricted to use the liquid crystal display for a long time while carrying the liquid crystal display, and the large capacity battery acts as an obstacle for improving the compactness and light weight of the liquid crystal display and the portability.

In order to solve the above problems, a reflection type liquid crystal display device having no backlight is proposed.

Since the reflective liquid crystal display does not use a backlight and only displays power required for the liquid crystal driving and driving circuits as the image is displayed using natural light, the amount of power consumed by the backlight can be greatly reduced.

Therefore, it is possible to use the liquid crystal display device for a long time while carrying it, to reduce the weight and portability of the liquid crystal display device, and to apply the entire unit pixel part as an opening part. The aperture ratio is superior to that of the device.

The reflective liquid crystal display is opaque in place of the transparent conductive pixel electrode provided in the transmissive liquid crystal display, and includes a reflective plate made of a metal material that reflects light. In this case, the reflector generates an electric field in the liquid crystal layer together with the common transparent electrode formed on the color filter substrate.

When an electric field is applied to the liquid crystal layer as described above, the liquid crystal rotates by dielectric anisotropy so that natural light or artificial light source incident from the outside is incident on the reflecting plate, and then transmits the light reflected from the reflecting plate toward the color filter substrate. The amount of is controlled by the voltage value of the data signal applied to the reflector.

The components of the reflective liquid crystal display as described above will be described in detail with reference to the accompanying drawings.

1 is a plan view of a unit pixel of a typical reflective liquid crystal display device.

Referring to Fig. 1, the gate wirings 4 are arranged in a row at regular intervals on the substrate, and the data wirings 2 are arranged in columns at regular intervals. Therefore, the gate wiring 4 and the data wiring 2 are arranged in matrix form. In this case, the unit liquid crystal cell is defined at each intersection of the data line 2 and the gate line 4, and includes a thin film transistor TFT and a reflector 14.

The gate electrode 10 of the thin film transistor TFT is formed by extending from a predetermined position of the gate line 4, and the source electrode 8 extends from the data line 2, thereby providing the gate electrode 10. And the predetermined area is overlapped.

The drain electrode 12 is formed at a position corresponding to the source electrode 8 based on the gate electrode 10, and the reflector 14 is formed through the drain contact hole 16 formed on the drain electrode 12. ) Is in electrical contact with the drain electrode 12.

The thin film transistor TFT may include a semiconductor layer for forming a conductive channel between the source electrode 8 and the drain electrode 12 by a scan signal supplied to the gate electrode 10 through the gate line 4. Not shown).

As such, the thin film transistor TFT forms a conductive channel between the source electrode 8 and the drain electrode 12 in response to the scan signal supplied from the gate wiring 4, and thus, the source electrode 8 through the data wiring 2. Is transmitted to the drain electrode 12.

Meanwhile, the reflective plate 14 connected to the drain electrode 12 through the drain contact hole 16 is substantially opaque and is formed of a metal material that reflects light. In this case, the reflector 14 generates an electric field in the liquid crystal layer together with a common transparent electrode (not shown) formed on the color filter substrate.

When the electric field is applied to the liquid crystal layer as described above, the liquid crystal rotates by dielectric anisotropy so that natural or artificial light sources incident from the outside are incident on the reflector 14, and then transmits the light reflected from the reflector 14 toward the color filter substrate. The amount of transmitted light is controlled by the voltage value of the data signal applied to the reflector 14.

The storage electrode 20 connected to the reflector 14 through the storage contact hole 22 is deposited on the gate wiring 4 to form a storage capacitor 18, and the storage electrode 20 and the gate wiring ( A gate insulating film (not shown) is deposited between 4) to form the thin film transistor TFT.

The storage capacitor 18 as described above is turned off after the voltage value of the scan signal is charged during the turn-on period of the thin film transistor to which the scan signal is applied to the gate wiring 4. The driving of the liquid crystal is maintained by supplying the charged voltage to the pixel electrode 14 during the turn-off period.

FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1, and a cross-sectional structure of a thin film transistor region of a general reflective liquid crystal display device will be described in detail with reference to the following.

First, the gate electrode 10 is patterned on the substrate 1, and a gate insulating film 30 is formed on the entire surface of the substrate 1 including the gate electrode 10. At this time, the gate electrode 10 is simultaneously patterned to extend at a predetermined position of the gate wiring 4 during the patterning of the gate wiring 4 as described above.

The active layer 36 is formed to cover the gate electrode 10 on the gate insulating layer 30, and the source electrode 8 is formed to be spaced apart from each other on the active layer 36. ) And the drain electrode 12 are patterned.

The active layer 36 is formed by stacking a semiconductor layer 32 made of amorphous silicon and an ohmic contact layer 34 made of n + amorphous silicon doped with phosphorus (P) at a high concentration. The ohmic contact layer 34 formed on the semiconductor layer 32 in a region where the source electrode 8 and the drain electrode 12 are spaced apart is removed in the process of patterning the source electrode 8 and the drain electrode 12.

On the other hand, the source electrode 8 and the drain electrode 12 extend from the top of the active layer 36 so as to be formed on the gate insulating film 30 as well.

In addition, a passivation film 38 made of SiNx is formed on the entire surface of the exposed substrate 1 including the source electrode 8 and the drain electrode 12 by chemical vapor deposition (CVD). Is deposited. A drain contact hole 16 exposing a part of the drain electrode 12 is formed on the passivation layer 38.

In addition, a reflective plate 14 is formed on the passivation layer 38, and the reflective plate 14 and the drain electrode 12 are electrically contacted through the drain contact hole 16.

FIG. 3 is a cross-sectional view taken along the line II-II 'of FIG. 1 and the cross-sectional structure of a storage capacitor region of a typical reflective liquid crystal display will be described in detail with reference to the following.

First, the gate wiring 4 is patterned on the substrate 1, and the gate insulating film 30 is formed on the entire surface of the substrate 1 including the gate wiring 4. In this case, the gate insulating layer 30 is simultaneously deposited during the deposition of the gate insulating layer 30 in the TFT region.

The storage electrode 20 is patterned on the gate insulating layer 30. In this case, the storage electrode 20 is patterned and formed at the same time during the patterning process of the source and drain electrodes 8 and 12 of the thin film transistor TFT.

The storage electrode 20 overlaps a portion of the gate line 4 with the gate insulating layer 30 therebetween to function as a storage capacitor 18.

In addition, a protective film 38 made of SiNx is deposited on the entire surface of the gate insulating layer 30 including the storage electrode 20 through chemical vapor deposition. A storage contact hole 22 exposing a portion of the storage electrode 20 is formed on the passivation layer 38. In this case, the passivation layer 38 is formed at the same time during the formation of the passivation layer 38 in the TFT region, and the storage contact hole 22 is formed at the same time during the formation of the drain contact hole 16 of the TFT. Is formed.

In addition, a reflective plate 14 is formed on the passivation layer 38, and the reflective plate 14 and the storage electrode 20 are electrically patterned through the storage contact hole 22.

FIG. 4 is a cross-sectional view taken along the line III-III 'of FIG. 1. Referring to this, an over-lap relationship between the data line 2, the gate line 4, and the reflector 14 is described as follows.

First, the gate wiring 4 is patterned on the entire upper surface of the substrate 1, and the gate insulating film 30 is deposited on the entire surface of the substrate 1 including the gate wiring 4.

The data line 2 is patterned on the gate insulating layer 30 to be spaced apart from the gate line 4.

A protective film 38 made of an inorganic insulating material such as SiNx is formed on the gate insulating film 30 including the data line 2.

The reflective plate 14 is patterned in an area where the data line 2 and the gate line 4 are spaced apart from each other on the passivation layer 38.

The above-described general reflection type liquid crystal display device has a relatively thin film when the reflecting plate 14 is extended to the upper portion of the protective film 38 having the data line 2 and the gate line 4 formed thereon in order to further improve the aperture ratio. ) And the reflective plate 14, the data line 2 and the gate line 4 are overlapped by the protective film 38 made of an inorganic dielectric material having a high dielectric constant, resulting in problems such as parasitic capacitance and the like. Falls out.

Therefore, recently, by applying an organic insulating film such as benzocyclobutene (BCB), spin-on-glass (SOG) or acryl, which has a low dielectric constant, as a protective film 38, Even if 14) overlaps with the data wiring 2 and the gate wiring 4, a liquid crystal display device having an improved aperture ratio by preventing signal characteristics from being lowered has been manufactured. The high-aperture reflective liquid crystal display device will be described in detail with reference to the accompanying drawings.

FIG. 5 is a plan view of a unit pixel of a typical high-aperture reflective liquid crystal display, and as shown therein, the reflector 14 is extended to overlap the edges of the data line 2 and the gate line 4. Except that, it is the same as the top view of FIG.

The reason why the reflector 14 may extend so as to overlap the edges of the data line 2 and the gate line 4 is that an organic insulating layer such as benzocyclobutene, spin-on-glass, or acrylic having a low dielectric constant is used. This is because, by forming a thick film and applying it as a protective film, mutual influence due to over-lap of the data line 2 and the gate line 4 and the reflector 14 can be prevented.

In addition, when an organic insulating layer such as benzocyclobutene, spin-on-glass, or acrylic is formed as a thick film and applied as a protective film, there is an additional effect that may contribute to planarization of the thin film transistor array substrate.

FIG. 6 is a cross-sectional view taken along the line IV-IV ′ of FIG. 5.

Referring to FIG. 6, the gate wiring 4 is patterned on the substrate 1, and the gate insulating film 30 is deposited on the entire surface of the substrate 1 including the gate wiring 4.

The data line 2 is patterned on the gate insulating layer 30 to be spaced apart from the gate line 4.

A thick film protective film 48 made of an organic insulating material such as benzocyclobutene, spin-on-glass, or acryl having a low dielectric constant is formed on the gate insulating film 30 including the data line 2. A thin film passivation layer 58 made of an inorganic insulating material such as SiNx is formed on the thick layer passivation layer 48.

The reflective plate 14 is patterned on the thin film passivation layer 58 so as to overlap the edges of the data line 2 and the gate line 4.

Accordingly, the liquid crystal layer is extended to overlap with the data line 2 and the gate line 4 by the thick film protective film 48 made of the organic insulating material and the thin film protective film 58 made of the inorganic insulating material. The aperture ratio of the display device is improved.

On the other hand, the reason for forming the thin film protective film 58 of the inorganic insulating film material on the thick film protective film 48 of the organic insulating film material is that the opaque metal reflective plate 14 directly on the thick film protective film 48 of the organic insulating film material In the case of deposition, the chamber in which deposition proceeds is prevented from being contaminated by organic matter.

The reflective plate 14 applied to the reflective liquid crystal display device reflects the natural light or artificial light source incident from the outside back to the color filter substrate by driving the liquid crystal so that an image is displayed, so that the reflection efficiency of the reflective plate 14 is increased. It directly affects the brightness of the display device.

However, as described above, since the surface of the reflective plate 14 is flattened and the area reflecting light is practically limited, there is a problem that the luminance characteristic of the reflective liquid crystal display device is lowered.

Therefore, in order to improve the luminance characteristic of the liquid crystal display, a method of forming a bend on the surface of the reflector 14 has been proposed.

7A to 7F are exemplary views sequentially illustrating a method of forming a bend of a reflecting plate in a reflective liquid crystal display, and the method of forming a reflecting plate of a conventional reflective liquid crystal display will be described in detail with reference to the following.

First, as shown in FIG. 7A, a resist film 102 made of a photosensitive resin material is uniformly coated on the substrate 101, and then prebaking is performed.

As shown in FIG. 7B, light is selectively irradiated onto the resist film 102 through a mask 103 in which light and non-transmissive regions of light are patterned.

As shown in FIG. 7C, the resist film 102 to which the light is selectively irradiated is developed to form a pattern of the resist film 102. As shown in FIG. In this case, the pattern of the resist film 102 has a square profile that protrudes on the substrate 101 by development.

Then, as shown in FIG. 7D, postbaking is performed on the pattern of the resist film 102. At this time, post-baking is performed to fix the pattern of the resist film 102. The post-baking causes the upper edge of the pattern of the resist film 102 to shrink and the side surface to swell. The edges become smooth throughout and have a curved profile that is close to a circle.

As shown in FIG. 7E, an over-coated layer 104 is formed on the entire surface of the substrate 101 including the pattern of the resist film 102. At this time, the overcoat layer 104 is formed along the curvature of the resist film 102 formed on the substrate 101.

As shown in FIG. 7F, the reflective plate 105 is deposited on the overcoat layer 104 by metal sputtering. In this case, the reflector plate 104 is formed along the curvature of the overcoat layer 104.

However, even if the reflecting plate 105 is formed to bend as described above to improve the reflecting efficiency of light, the reflecting plate 105 having still more improved reflecting efficiency is required to realize high brightness of the reflective liquid crystal display device. .

Accordingly, the present invention has been made to solve the conventional problems as described above, the object of the present invention is to reflect the reflection plate structure of the liquid crystal display device applied to the liquid crystal display device and a manufacturing method thereof To provide.

1 is a plan view of a unit pixel of a typical reflective liquid crystal display device;

FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1;

3 is a cross-sectional view taken along the line II-II 'of FIG.

4 is a cross-sectional view taken along the line III-III 'of FIG. 1;

5 is a plan view of a unit pixel of a general high-aperture reflective liquid crystal display device;

FIG. 6 is a cross-sectional view taken along the line IV-IV 'of FIG. 5;

7A to 7F are exemplary views showing a conventional reflective plate manufacturing method in a sequential cross section in a typical reflective liquid crystal display device.

8 is an exemplary view showing a reflector plate structure of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 9 is a cross-sectional view taken along the line VV ′ of FIG. 8; FIG.

10A to 10G are exemplary views showing, in sequential cross section, a method of manufacturing a reflector structure of a liquid crystal display according to a first embodiment of the present invention.

11A and 11B are exemplary views of a test pattern for experimenting with the influence of the resist film pattern by postbaking in Fig. 10E.

12A to 12D are cross-sectional SEM views of test patterns according to respective heat treatment conditions in FIGS. 11A and 11B.

13 is an exemplary view showing a reflector plate structure of a liquid crystal display device according to a second embodiment of the present invention.

14A to 14E are exemplary views showing, in sequential cross-section, a method for manufacturing a reflector structure of a liquid crystal display according to a second embodiment of the present invention.

15 is an exemplary view showing a reflector structure of a liquid crystal display according to a third embodiment of the present invention.

16A to 16F are exemplary views showing, in sequential cross section, a method for manufacturing a reflector structure of a liquid crystal display according to a third embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

200: reflector plate 201: horizontal grooves

202: vertical grooves 203: pyramidal projection

First, the first embodiment of the reflective plate structure of the liquid crystal display device to achieve the object of the present invention as described above is a vertical intersection of the longitudinally spaced longitudinal grooves and the vertically spaced vertical grooves, The pyramid-shaped protrusions are provided in an area defined by the vertical intersection of the horizontal grooves and the vertical grooves.

In addition, a second embodiment of the reflective plate structure of the liquid crystal display device for achieving the object of the present invention as described above is formed on the substrate, pyramidal projections having a line width and a distance of 0.5㎛ ~ 1.5㎛ range A pattern of a photosensitive film provided with; And a protective film and a reflecting plate sequentially stacked along the pattern curvature of the photosensitive film.

The third embodiment of the reflective plate structure of the liquid crystal display device for achieving the object of the present invention as described above is characterized in that the hemispherical grooves of a predetermined size are arranged adjacent to each other.

In addition, the method of manufacturing a reflective plate structure of a liquid crystal display according to the first embodiment of the present invention includes the steps of forming a reflective plate on a substrate; Forming a photosensitive film on the reflective plate; Exposing and developing the photosensitive film to form a pattern of the photosensitive film such that pyramidal protrusions having a uniform line width and separation distance in a range of 0.5 μm to 1.5 μm are provided; Etching the reflecting plate through the pattern of the photosensitive film to transfer the bent shape according to the pattern of the photosensitive film onto the reflecting plate; And removing the remaining pattern of the photosensitive film.

In addition, the method of manufacturing a reflective plate structure of a liquid crystal display device according to a second embodiment of the present invention includes the steps of forming a photosensitive film on a substrate; Exposing and developing the photosensitive film to form a pattern of the photosensitive film such that pyramidal protrusions having a line width and a separation distance in a range of 0.5 μm to 1.5 μm are provided; And forming a protective film and a reflecting plate sequentially on the substrate along the pattern of the photosensitive film, thereby transferring the bent shape according to the pattern of the photosensitive film to the reflecting plate.

In addition, the method of manufacturing a reflector plate structure of a liquid crystal display device according to a third embodiment of the present invention includes the steps of forming a reflector plate on a substrate; Forming a photosensitive film on the reflective plate; Exposing and developing the photosensitive film to form a pattern of the photosensitive film so that a reflecting plate is exposed at a predetermined distance; Wet etching the exposed regions of the reflector through a pattern of the photosensitive film such that hemispherical grooves of constant size are arranged adjacent to each other on the surface of the reflector; And removing the remaining pattern of the photosensitive film.

Embodiments of the reflective plate structure and the method of manufacturing the same according to the present invention as described above will be described in detail with reference to the accompanying drawings.

8 is an exemplary view showing a reflector structure of a liquid crystal display according to a first embodiment of the present invention.

Referring to FIG. 8, in the reflective plate 200, vertical grooves 202 vertically spaced apart from horizontal grooves 201 are regularly spaced apart from each other. The pyramid-shaped protrusions 203 are provided in an area defined by the vertical intersection of the grooves 202.

The reflector 200 is formed of one material selected from Al, AlNd, Ag, or Ag alloy, and the pyramidal protrusions 203 may be formed to have a maximum height in a range of about 0.5 μm to 5 μm. .

9 is a cross-sectional view taken along the line VV ′ of FIG. 8.

Referring to FIG. 9, in the reflector 200, sawtooth-shaped protrusions 203 are formed adjacent to each other by grooves 202 having a 'V' shape.

As described above, the reflector 200 is formed of one material selected from Al, AlNd, Ag, or Ag alloy, and the sawtooth-shaped protrusions 203 (that is, the pyramid-shaped protrusions of FIG. 8) have a maximum height of 0.5. It has a range of about µm to 5 µm.

Meanwhile, a method of manufacturing a reflector structure of the liquid crystal display according to the first embodiment of the present invention will be described in detail with reference to the exemplary view showing the sequential cross-sectional configuration of FIGS. 10A to 10G.

First, referring to FIG. 10A, a reflector 200 is formed on a substrate 210. At this time, the reflective plate 200 is formed of a material selected from Al, AlNd, Ag or Ag alloy to a thickness of about 0,5㎛ to 5㎛.

As shown in FIG. 10B, a resist film 211 made of a photosensitive resin material is uniformly coated on the reflective plate 200, and then prebaking is performed. At this time, prebaking is performed to evaporate the moisture contained in the resist film 211.

As shown in FIG. 10C, exposure is selectively performed on the resist film 211 through a mask 212. FIG. In this case, although the conventional exposure apparatus has a resolution limit that can define a pattern of about 3 to 5 µm, the present invention provides a line width in the range of 0.5 µm to 1.5 µm lower than the limit resolution of the conventional exposure apparatus. The exposure is performed so that a pattern having a separation distance is defined.

Therefore, when the selectively exposed resist film 211 is developed as shown in FIG. 10D, the pattern of the remaining resist film 211 has a uniform line width and separation distance having a cross-sectional shape in the range of 0.5 µm to 1.5 µm. It has a sawtooth-shaped uneven structure. In practice, the pattern of the resist film 211 has a form similar to the pyramid-shaped protrusions 203 shown in the example of FIG.

Then, as shown in Fig. 10E, postbaking is performed on the pattern of the resist film 211. At this time, post-baking is carried out for 1 to 5 minutes at a temperature of about 120 ° C to 160 ° C in order to fix the remaining pattern of the resist film 211.

Comparing Fig. 10E to Fig. 7D, the pattern of the resist film 211 according to the present invention is hardly affected by postbaking. This will be described later in detail with reference to the experimental results.

As shown in FIG. 10F, the reflective plate 200 is etched through the pattern of the resist film 211. In this case, the etching of the reflector 200 is preferably performed by applying dry etching having a directional direction until a groove having a maximum depth of about 0.5 μm to 5 μm is formed from the surface of the reflector 200.

As the pattern of the resist film 211 is gradually etched according to the etching, the etching of the reflective plate 200 exposed is performed, so that the sawtooth-shaped uneven structure of the pattern of the resist film 211 is transferred to the reflecting plate 200. . In practice, the reflector 200 includes the pyramidal protrusions 203 shown in the exemplary diagram of FIG. 8.

Then, as shown in Fig. 10G, the remaining pattern of the resist film 211 is removed.

Reflective plate 200 according to the first embodiment of the present invention as described above and the method of manufacturing the reflector plate 200 by maximizing the effective reflecting area and the inclined surface area, which is advantageous for the condensing and diffuse reflection of natural light or artificial light source incident from the outside Having a structure improves reflection efficiency.

Therefore, when the reflecting plate according to the first embodiment of the present invention is applied as a reflecting electrode of a liquid crystal display device such as a reflection type or a transmissive reflection type, the luminance characteristic and the viewing angle characteristic of the liquid crystal display apparatus can be improved.

Hereinafter, the reason why the pattern of the resist film 211 according to the present invention is hardly affected by postbaking will be described in detail with reference to the experimental results.

First, as shown in FIGS. 11A and 11B, 100 patterns 300 having a 1 μm line width and a separation distance on a Cr coated substrate (not shown) and a pattern having a 2 μm line width and a distance ( 400) 100. In this case, as the Cr coated substrate is applied, it is possible to easily determine whether residues and scums are generated in the patterns 300 and 400 having a line width and a distance of 1 μm and 2 μm. In addition, the application, exposure and development of the resist film for forming the patterns 300 and 400 having a line width and a distance of 1 μm and 2 μm were applied in a conventional process.

Then, heat treatment is performed on the patterns 300 and 400 having the line width and the distance of 1 μm and 2 μm through the conditions shown in Table 1 below.

Temperature condition (℃) First heat treatment unit Second heat treatment unit Heat treatment condition 1 120 130 Heat treatment condition 2 130 140 Heat treatment condition 3 140 150 Heat treatment condition 4 150 160

In addition, cross-sectional SEM (scanning electron microscope) of patterns 300 and 400 having a line width and a separation distance of 1 μm and 2 μm according to the heat treatment conditions 1 to 4 were observed, which are shown in FIGS. 12A to 12D.

First, when the heat treatment condition 1 is applied to the patterns 300 and 400 having a 1 μm and 2 μm line width and a distance therebetween, as shown in FIG. 12A, all of the patterns 300 and 400 having a 1 μm and 2 μm line width and a spaced distance are shown. Profile deformation is very fine.

When the heat treatment condition 2 and the heat treatment condition 3 are applied to the patterns 300 and 400 having the 1 μm and 2 μm line widths and the distance therebetween, as shown in FIGS. 12B and 12C, the patterns having the 1 μm line width and the separation distance ( Although 300 is still fine in profile deformation, the pattern 400 having a 2 μm line width and a separation distance exhibits prominent profile deformation. That is, the pattern 400 having a line width and a separation distance of 2 μm gradually contracts the upper edge by heat treatment condition 2 and heat treatment condition 3, and swells the sides of the pattern 400 so as to smooth the edge as a whole and deforms the profile close to the hemispherical shape.

In addition, when the heat treatment condition 4 is applied to the patterns 300 and 400 having the 1 μm and the 2 μm line widths and the separation distance, the pattern 300 having the 1 μm line width and the separation distance still has profile deformation as shown in FIG. 12D. Although fine, the pattern 400 having a 2 μm line width and a separation distance has a hemispherical shape due to the sharp deformation of the profile.

Therefore, since the exposure of the pattern of the resist film 211 shown in FIG. 10E has a line width and a separation distance in the range of 0.5 µm to 1.5 µm, profile deformation is caused by post-baking as can be seen from the above experimental results. It rarely occurs.

On the other hand, the planar configuration of the reflecting plate structure of the liquid crystal display according to the second embodiment of the present invention is similar to that of the first embodiment of the present invention, but is differentiated in its cross-sectional configuration.

That is, referring to the exemplary view of FIG. 13, a pattern of a photoresist resist film 502 having a pyramidal shape protrusion having a line width and a separation distance in a range of 0.5 μm to 1.5 μm is formed on a substrate 501. And a protective film 503 and a reflecting plate 500 stacked along the pattern curvature of the resist film 502.

Like the first embodiment of the present invention, the reflective plate 500 is formed of one material selected from Al, AlNd, Ag, or Ag alloy.

In addition, since the reflective plate 500 is formed along the pattern curvature of the resist film 502 having the pyramid-shaped protrusions having a line width and a separation distance in the range of 0.5 μm to 1.5 μm, similar to the first embodiment of the present invention. It will have a flat configuration.

A method of manufacturing a reflective plate structure of a liquid crystal display according to the second exemplary embodiment of the present invention as described above will be described in detail with reference to the sequential cross-sectional views of FIGS. 14A to 14E.

First, as shown in FIG. 14A, a resist film 502 made of photosensitive resin is uniformly applied onto the substrate 501, and then prebaking is performed. At this time, prebaking is performed to evaporate the moisture contained in the resist film 501.

As shown in Fig. 14B, exposure is selectively performed on the resist film 502 through a mask 510. Figs. In this case, the conventional exposure equipment has a limit resolution capable of defining a pattern of about 3 μm to 5 μm, but the present invention has a line width and a separation distance in the range of 0.5 μm to 1.5 μm lower than the limit resolution of the conventional exposure device. Exposure is performed to define a pattern.

Therefore, when the selectively exposed resist film 502 is developed as shown in Fig. 14C, the pattern of the remaining resist film 502 has a uniform line width and separation distance having a cross-sectional shape in the range of 0.5 mu m to 1.5 mu m. It has a sawtooth-shaped uneven structure. In practice, the pattern of the resist film 502 has a form similar to the pyramidal protrusions 203 shown in the exemplary diagram of FIG.

Then, as shown in FIG. 14D, post-bake is performed on the pattern of the resist film 502. FIG. At this time, post-baking is usually performed for 1 to 5 minutes at a temperature of about 120 ° C to 160 ° C in order to fix the remaining pattern of the resist film 502. It can be seen that almost no profile deformation of the resist film 502 having a line width and a separation distance in the range of 1.5 mu m occurs.

As shown in FIG. 14E, the protective film 503 and the reflecting plate 500 are sequentially formed on the substrate 501 along the pattern of the resist film 502, thereby forming a bent shape according to the pattern of the resist film 502. Is transferred to the reflector plate 500. In this case, the protective film 503 is formed to prevent contamination of the reaction chamber as the opaque metal reflective plate 500 is deposited directly on the resist film 502, which is typically an organic film.

The reflective plate 500 is formed along the pattern curve of the resist film 502 having the pyramid-shaped protrusions having a line width and a separation distance in a range of 0.5 μm to 1.5 μm, and thus reflecting plate according to the first embodiment of the present invention. It has a planar configuration similar to (200).

Accordingly, the reflective plate 500 according to the second embodiment of the present invention maximizes the effective reflecting area and the inclined surface area as in the first embodiment of the present invention, which is advantageous for the light collection and diffuse reflection of natural or artificial light sources incident from the outside. Having a structure improves reflection efficiency.

Therefore, when the reflecting plate according to the first embodiment of the present invention is applied as a reflecting electrode of a liquid crystal display device such as a reflection type or a transmissive reflection type, the luminance characteristic and the viewing angle characteristic of the liquid crystal display apparatus can be improved.

On the other hand, the reflective plate structure of the liquid crystal display according to the third embodiment of the present invention is characterized in that the hemispherical grooves of a predetermined size are arranged adjacent to each other.

That is, referring to the exemplary view of FIG. 15, in the reflective plate 600, hemispherical grooves 601 having a constant size are arranged adjacent to each other.

Like the first and second embodiments of the present invention, the reflecting plate 600 is formed of one material selected from Al, AlNd, Ag, or Ag alloy, and the hemispherical grooves 601 have a maximum depth of 0.5 μm to 5 μm. It is formed to have a range of a degree.

16A to 16F are exemplary views showing, in sequential cross section, a method of manufacturing a reflecting plate of a liquid crystal display according to a third exemplary embodiment of the present invention.

First, as shown in FIG. 16A, the reflective plate 600 is formed on the substrate 610. At this time, the reflective plate 600 is formed of a material selected from Al, AlNd, Ag or Ag alloy to a thickness of about 0.5㎛ to 5㎛.

As shown in FIG. 16B, a resist film 611 made of a photosensitive resin material is uniformly coated on the reflective plate 600, and then prebaking is performed. At this time, prebaking is performed to evaporate the moisture contained in the resist film 611.

As shown in Fig. 16C, exposure is selectively performed on the resist film 611 through a mask 612.

As shown in Fig. 16D, the selectively exposed resist film 611 is developed to form a pattern of the resist film 611 so that the reflecting plate 600 is exposed at a predetermined distance, and then postbaking is performed. At this time, post-baking is carried out for 1 to 5 minutes at a temperature of about 120 ° C to 160 ° C in order to fix the remaining pattern of the resist film 611. At this time, whether or not the resist film 611 is deformed by postbaking does not significantly affect the third embodiment of the present invention. That is, the deformation of the resist film 611 may or may not occur.

As shown in FIG. 16E, the exposed regions of the reflector 600 are wet etched so that hemispherical grooves 601 having a predetermined size are arranged adjacent to each other on the surface of the reflector 600. At this time, since the wet etching has an isotropic characteristic, the region where the reflecting plate 600 is covered by the pattern of the resist film 611 is also affected by the etching. As a result, the hemispherical grooves 601 having a constant size are formed in the reflecting plate 600. Is formed.

Then, as shown in Fig. 16F, the remaining pattern of the resist film 611 is removed.

In order to allow the hemispherical grooves 601 of a predetermined size to be arranged adjacent to each other on the surface of the reflecting plate 600, the following matters should be considered.

The line width and the separation distance of the pattern of the resist film 611 exposing the surface of the reflecting plate 600 at regular distances should be controlled appropriately, which should be considered in the exposure process of the resist film 611.

In addition, the wet etching conditions for etching the exposed region of the reflective plate 600 by the pattern of the resist film 611 should be appropriately adjusted. That is, by adjusting the wet etching conditions to change the depth of the hemispherical grooves 601, hemispherical grooves 601 can be adjacent to each other. It is preferable to set the condition of the wet etching so that the maximum depth of the hemispherical grooves 601 has a range of about 0.5 μm to 5 μm.

According to the reflective plate structure and the manufacturing method according to the third embodiment of the present invention as described above, unlike the first and second embodiments of the present invention, the reflective plate 600 does not have projections of pyramidal shape, but the hemispherical grooves 601. As a result, the effective reflecting area and the inclined surface area are maximized as in the first and second embodiments, resulting in a structure that is advantageous for condensing and diffuse reflection of natural or artificial light sources incident from the outside, thereby improving reflection efficiency. .

As described above, the reflective plate and the manufacturing method of the liquid crystal display according to the present invention provide a reflective plate provided with a pyramidal protrusion or hemispherical groove.

The reflection plate provided with the pyramid-shaped protrusions or hemispherical grooves maximizes the effective reflection area and the inclined surface area, thereby improving the reflection efficiency by having a structure that is advantageous for the light collection and diffuse reflection of natural or artificial light sources incident from the outside.

Therefore, when the reflecting plate according to the present invention is applied as a reflecting electrode of a liquid crystal display device such as a reflection type or a transmissive reflection type, it is possible to improve the luminance characteristic and the viewing angle characteristic of the liquid crystal display device.

Claims (11)

A reflector structure of a liquid crystal display device, characterized in that the pyramid-shaped projections having a line width and a separation distance in the range of 0.5㎛ ~ 1.5㎛. The reflective plate structure of claim 1, wherein the pyramidal protrusions are formed by extending a metal material forming a reflective plate. The photosensitive film of claim 1, wherein the pyramidal protrusions have a pattern of a photosensitive film having pyramidal protrusions having a line width and a distance therebetween in a range of 0.5 μm to 1.5 μm; And a protective film and a reflecting plate sequentially stacked along the pattern curvature of the photosensitive film. A reflector structure of a liquid crystal display device, characterized in that hemispherical grooves of constant size are arranged adjacent to each other. The reflection plate structure according to any one of claims 1 to 4, wherein the reflection plate is made of Al, AlNd, Ag, or Ag alloy. The reflective plate structure of claim 1, wherein the pyramidal protrusions have a maximum height in a range of 0.5 μm to 5 μm. Forming a reflecting plate on the substrate; Forming a photosensitive film on the reflective plate; Exposing and developing the photosensitive film to form a pattern of the photosensitive film having pyramidal protrusions having a line width and a separation distance in a range of 0.5 μm to 1.5 μm; Etching the reflecting plate through the pattern of the photosensitive film to transfer the bent shape according to the pattern of the photosensitive film onto the reflecting plate; And removing the remaining pattern of the photosensitive film. The method of claim 11, wherein the etching of the reflective plate is performed dry. Forming a photosensitive film on the substrate; Exposing and developing the photosensitive film to form a pattern of the photosensitive film having pyramidal protrusions having a line width and a separation distance in a range of 0.5 μm to 1.5 μm; And sequentially forming a protective film and a reflecting plate along the pattern of the photosensitive film on the substrate, thereby transferring a bent shape according to the pattern of the photosensitive film to the reflecting plate. The method of claim 9, wherein the forming of the photosensitive film on the reflective plate comprises: applying the photosensitive film on the reflective plate; A method of manufacturing a reflector of a liquid crystal display device, comprising prebake on the photosensitive film. The process of claim 7 or 9, wherein the photosensitive film is exposed and developed to form a pattern of the photosensitive film having projections in the form of pyramids having a line width and a separation distance in a range of 0.5 µm to 1.5 µm. Selectively exposing through; Developing the selectively exposed photosensitive film to form a pattern of the photosensitive film having pyramidal protrusions having a line width and a separation distance in a range of 0.5 μm to 1.5 μm; A method of manufacturing a reflector of a liquid crystal display device, characterized in that the step of performing a post-baking on the pattern of the photosensitive film.