KR20020096395A - Reflection-penetration type liquid crystal display device and method for fabricating thereof - Google Patents

Abstract

PURPOSE: A transflective liquid crystal display device and a method for fabricating the same are provided to carry out the display with a minimum power consumption but with high luminance at a place where the light amount is lacked while carrying out the display by using the external light in the other places, thereby improving the display performance. CONSTITUTION: A transflective liquid crystal display device includes a first substrate, a light refraction pattern layer(135) formed on the first substrate by a first pitch interval and having a plurality of micro lenses(125) formed continuously for focussing light, thin film transistors(150) formed between front end parts of the micro lenses with drain electrodes, an organic insulating film(160) formed on the first substrate by a thickness of the first pitch or less and having openings for exposing the drain electrodes, transmission electrodes(170) electrically connected to the drain electrodes of the thin film transistors, reflecting electrodes(180) formed on the transmission electrodes and having opened windows(185) for passing the light focussed by the micro lenses, a second substrate facing the first substrate, and liquid crystal(220) implanted between the substrates.

Description

Reflective-transmissive liquid crystal display and its manufacturing method {REFLECTION-PENETRATION TYPE LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR FABRICATING THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection-transmissive liquid crystal display device and a method of manufacturing the same. More particularly, the present invention relates to a display in a reflection mode where light is abundant and to a transmission mode in a light shortage. The present invention relates to a reflection-transmissive liquid crystal display device which not only performs display but also enhances display brightness in a transmission mode.

Recently, with the development of the technology of the information processing apparatus, the development of the technology of the "display device" for interfacing so that the user can recognize the data processed by the information processing apparatus has been made.

Display devices that play such roles can be broadly classified into analog display devices and digital display devices.

An analog display device is typically a CRT type display device (Cathode Ray Tube type display device), a digital display device is typically a liquid crystal display (Liquid Crystal Display device).

All of them have excellent display performance, but in terms of weight and volume, the liquid crystal display device has much superior advantages over the CRT display device.

The liquid crystal display device having such an advantage is divided into three methods according to the method of using light.

The first method is a method of performing display using external light, and it is possible to display a liquid crystal display with extremely low power consumption. A liquid crystal display device that displays in this manner will be defined as a "reflection type liquid crystal display device."

In the second method, a display is performed by using artificial light generated by consuming electric energy charged in the liquid crystal display, and it is possible to display the liquid crystal display regardless of an external environment. A liquid crystal display device which displays in this manner will be defined as a “penetration type liquid crystal display device”.

However, the above-described reflective liquid crystal display device has a disadvantage in that it is impossible to display in a dark place where it is difficult to distinguish characters, images, and videos due to lack of light, and the transmissive liquid crystal display device can display in a dark place where the light amount is insufficient. This has a big disadvantage.

In the third method, display is performed by using external light where light is abundant, and by using artificial light produced by itself only where light is insufficient. It has an advantage that can be reduced. A liquid crystal display device which displays in this manner will be defined as a "reflection-penetration type liquid crystal display device."

3 shows a profile of a conventional reflective-transmissive liquid crystal display 20.

Referring to FIG. 3, a thin film transistor 7 is performed on the top surface of the first substrate 1 by a thin film transistor manufacturing process. Reference numeral 2 is a gate insulating film, 3 is a gate electrode, 6b is a source electrode, 6a is a drain electrode, and 4 and 5 are active patterns.

Thereafter, a transparent and thin organic insulating film 15 is applied to the upper surface of the thin film transistor 7 to a predetermined thickness.

In this case, an irregular concave-convex pattern is formed on the upper surface of the organic insulating layer 15 to scatter light to improve brightness, and a portion of the organic insulating layer 15 corresponding to the drain electrode 6a of the thin film transistor 7 is opened. .

Thereafter, reflection / transmission electrodes 8 and 10 necessary for controlling the liquid crystal are formed on the upper surface of the organic insulating layer 15. Reference numeral 9 is an insulating film formed between the reflective / transmissive electrodes 8 and 10.

In this case, the reflective / transmissive electrodes 8 and 10 are composed of a double film of a transmissive electrode 8 that transmits light and a reflective electrode 10 that reflects light, and a part of the reflective electrode 10 is an opening 11. Light is transmitted through this portion.

In this case, ITO or IZO material is used as the transmissive electrode 8 of the reflective / transmissive electrodes 8 and 10, and aluminum or aluminum-neodymium alloy having excellent reflectance is mainly used as the reflective electrode 10.

Thereafter, the second substrate 14 having the common electrode 13 formed thereon is positioned on the upper surface of the first substrate 1, and the liquid crystal 12 is injected therebetween, whereby the reflection-transmissive liquid crystal display 20 is manufactured. .

However, such a conventional reflection / transmission liquid crystal display 20 passes through the opening 11 of the reflection / transmission electrodes 8 and 10 when performing display in the transmission mode, that is, from the bottom of the first substrate 1. When the display is performed using the light A, the directionality of the light is irregular so that the amount of light that can pass through the opening 11 after passing through the first substrate 1 is insufficient, resulting in a decrease in display brightness.

Accordingly, the present invention has been made in view of such a conventional problem, and a first object of the present invention is to provide a reflection-transmissive liquid crystal display device for improving display brightness and performing low power consumption display in a transmission mode.

A second object of the present invention is to provide a method of manufacturing a reflection-transmissive liquid crystal display device for improving display brightness in a transmission mode.

FIG. 1A illustrates a process of forming an adhesive layer on an upper surface of a first substrate as one of processes for forming a photorefractive pattern layer on a first substrate according to an embodiment of the present invention.

FIG. 1B is a process diagram illustrating coating of a photoreactive monomer on an upper surface of an adhesive layer as one of processes for forming a photorefractive pattern layer on a first substrate according to one embodiment of the present invention.

FIG. 1C is a process diagram illustrating photorefractive pattern formation and ultraviolet curing by patterning a photoreactive monomer as one of processes for forming a photorefractive pattern layer on a first substrate according to one embodiment of the present invention.

FIG. 1D is a process diagram illustrating the formation of a flat film on the light refraction pattern as one of the processes of forming the light refraction pattern layer on the first substrate according to one embodiment of the present invention.

FIG. 1E is a process diagram illustrating the formation of a thin film transistor on an upper surface of a photorefractive pattern layer according to an embodiment of the present invention.

FIG. 1F is a process diagram illustrating the formation of an organic insulating film having contact holes and irregularities formed on an upper surface of the photorefractive pattern layer according to one embodiment of the present invention.

FIG. 1G is a flowchart illustrating the formation of a transmission electrode and a reflection electrode on an upper surface of an organic insulating layer according to an exemplary embodiment of the present invention.

1H is a process diagram illustrating a reflection-transmissive liquid crystal display device in which a liquid crystal is injected after aligning a second substrate to a first substrate according to an embodiment of the present invention.

FIG. 2 is a graph illustrating a change in luminance depending on a distance between the microlens and the reflective electrode.

3 is a cross-sectional view illustrating a profile of a conventional reflection-transmissive liquid crystal display device.

Such a reflective-transmissive liquid crystal display device for realizing the first object of the present invention comprises: a first substrate; A light refracting pattern layer having a plurality of micro lenses formed on the first substrate at a first pitch interval and continuously formed to collect light; Thin film transistors formed between front ends of the micro lenses, and each having a drain electrode formed thereon; An organic insulating layer formed on an upper surface of the first substrate to a thickness less than or equal to a first pitch and having an opening exposing drain electrodes; Transmission electrodes formed to be electrically connected to drain electrodes of the thin film transistors; Reflective electrodes formed on the upper surfaces of the transmissive electrodes and having an aperture window through which the light collected by the microlenses passes; A second substrate provided opposite the first substrate; And a liquid crystal formed between the first substrate and the second substrate.

In addition, a method of manufacturing a reflection-transmissive liquid crystal display device for realizing a second object of the present invention includes: i) a light having a plurality of micro lenses continuously formed at a first pitch interval on a first substrate to collect light; Forming a refractive pattern layer; Ii) forming thin film transistors formed between the tips of the micro lenses, each having a drain electrode formed thereon; Iii) forming an organic insulating film having a thickness less than or equal to a first pitch on an upper surface of the first substrate, and forming contact holes to expose drain electrodes on the organic insulating film; Iii) forming transmissive electrodes in electrical connection with the drain electrodes; Iii) forming reflective electrodes on the upper surface of the transmissive electrodes, the apertured window through which the light collected by the micro lens passes; Iii) providing a second substrate to face the first substrate; And iii) injecting liquid crystal between the first substrate and the second substrate.

According to the present invention, where the amount of light is insufficient, it is possible to perform the display by consuming electric energy, and where the amount of light is rich, the display is performed using external light to perform the display with minimum power consumption, as well as the amount of light is insufficient. It greatly improves display performance by greatly improving the brightness required when performing display in the same place.

Hereinafter, a reflection-transmissive liquid crystal display device and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1H, a reflective-transmissive liquid crystal display device 100 is a transparent substrate through which light can pass, and in one embodiment, a glass substrate having a high light transmittance. Hereinafter, reference numeral 100 will be defined as a first substrate.

On the upper surface of the first substrate 100 defined as described above, the light refraction pattern layers 135 which collect light at first intervals are formed.

The light refraction pattern layers 135 serve to significantly increase the brightness of the light by allowing the direction of the light to be corrected while passing the non-directional light.

The photorefractive pattern layers 135, which perform such a role, are composed of an adhesive layer 110, a micro lens 125, and a flat film 140.

More specifically, the adhesive layer 110 is an organo-silane adhesive thinly coated on the upper surface of the first substrate 100.

On the upper surface of the adhesive layer 110, microlenses 125 for condensing light are formed in parallel with each other at first pitch intervals.

In detail, the microlens 125 has a shape in which the tip and the valley are continuously repeated by the inclined surface in the form of a rod prism having a bottom surface attached to the adhesive layer 110.

In this case, the first pitch coincides with the pixel pitch, and the optical refractive index of the microlens 125 is about 1.48 to 1.56.

Meanwhile, the flat film 140 is formed over the entire surface of the first substrate 100 in the state where the microlens 125 is formed on the upper surface of the adhesive layer 110.

The planar film 140 is to change the exit angle of the light passing through the microlens 125 to condense the light and to manufacture the thin film transistor 150 on the microlens 125. .

The flat film 140 is formed by spin-coating a solution obtained by dissolving a soluble amorphous fluoropolymer (Teflon AF, trade name) in a fluorinated solvent (3M: Fluorinert, trade name). .

In this case, the flat film 140 has a refractive index of 1.31 to 1.35 that is different from that of the microlens 125.

In this case, the light condensing function of the light may be further improved by allowing the microlens 125 and the flat film 140 to have different refractive indices.

The thin film transistor 150 is formed on the top surface of the flat film 140 of the light refraction pattern layer 135 having the above configuration.

In this case, the thin film transistor 150 may correspond to a valley corresponding to the tip of the micro lens 125 and the micro reds 125 of the flat film 140 so as not to disturb the flow of the light condensed by the micro lens 125 in one embodiment. It is formed in the portion corresponding to.

In one embodiment, the thin film transistor 150 includes a gate electrode 142, a gate insulating layer 144, a channel layer 146, a source electrode 147, and a drain electrode 148.

When the turn-on power is applied to the gate electrode 142 in a state in which the predetermined power is applied to the source electrode 147, the thin film transistor 150 is supplied with the power applied to the source electrode 147 to the channel layer 146. Through the drain electrode 148 to be output.

In the state where the thin film transistor 150 is formed, the organic insulating layer 160 is formed over the entire surface of the first substrate 100.

A contact hole 165 is formed at a position at which the drain electrode 148 of each of the thin film transistors 150 is exposed in the organic insulating layer 160, and external light is reflected in the remaining portion except the contact hole 165. The unevenness 167 is formed to sufficiently diffuse.

Meanwhile, a transmissive electrode 170 made of an ITO material or an IZO material is formed on an upper surface of the organic insulating layer 160 to be connected to the drain electrode 148 of the thin film transistor 150 exposed through the contact hole 165.

An upper surface of the transmissive electrode 170 is formed with a reflective electrode 180 made of a material having excellent reflectivity, such as aluminum and aluminum alloy.

In this case, an opening 185 is formed in a portion of the reflective electrode 180 that corresponds to the microlens 125 of the light refractive pattern layer 135 described above.

In this structure, light supplied by the microlens 125 of the light refraction pattern layer 135 is transmitted through the opening 185 of the reflective electrode 180, and external light is reflected by the reflective electrode 180. Be sure to

In this case, the luminance of the light collected from the microlens 125 of the light refraction pattern layer 135 is changed by the distance between the reflective electrode 180 and the microlens 125 of the light refraction pattern layer 135.

That is, the distance between the reflective electrode 180 and the microlens 125 is important in order to maximize the luminance of the light collected from the microlens 125 of the light refraction pattern 135.

2, the width of the microlens 125 and the distance formed by the reflective electrode 180 are the same, where each microlens 125 is located as shown in graph a. Produces the maximum luminance.

However, when the distance between the microlens 125 and the reflective electrode 180 is greater than the pitch of the microlens 125, the luminance is rapidly lowered as shown in graph b.

That is, as the distance between the reflective electrode 180 and the microlens 125 increases, the light collected by the microlens 125 is emitted to the outside through the opening 185 of the reflective electrode 180, and then the luminance is increased. Deteriorated, it means that the distance made by the reflective electrode 180 from the surface of the microlens 125 should be equal to or smaller than the width of the microlens 125.

The first substrate 100 having the above configuration is aligned with the second substrate 210 on which the common electrode 190 and the RGB pixel 200 are formed, and the first substrate 100 and the second substrate 210 are aligned with each other. Between the liquid crystal 220 is injected to produce a reflection-transmissive liquid crystal display device 230.

Hereinafter, a method of manufacturing the reflection-transmissive liquid crystal display device 230 according to an embodiment of the present invention will be described in more detail with reference to FIGS. 1A to 1H.

1A to 1D, a process of forming the light refraction pattern layer 135 on the first substrate 100 is described.

Referring to FIG. 1A, an organo-silane adhesive layer 110 is thinly coated on an upper surface of the first substrate 100 having excellent light transmittance.

Thereafter, as illustrated in FIG. 1B, a predetermined amount of a photo-curable monomer 120 is coated on the upper surface of the organo-silane adhesive layer 110. At this time, the photocurable monomer 120 is exposed to light so as not to be cured.

Thereafter, as shown in FIG. 1C, the photocurable monomer 120 is positioned on the upper surface of the photocurable monomer 120 in a state in which a transparent mold 130 having a pattern in which a profile is formed by continuously connecting a plurality of rod prisms is formed. Press to form the photocurable monomer 120 on the upper surface of the organo-silane adhesive layer 110 to have a rod prism shape.

Subsequently, as illustrated in FIG. 1C, ultraviolet rays are injected from the upper surface of the transparent mold 130 toward the photocurable monomer 120 formed to have a rod prism shape. As a result, the photocurable monomer 120 is cured while maintaining the state. Hereinafter, the photocurable monomer 120 cured in a predetermined form will be defined as a micro lens 125.

Subsequently, the transparent mold 130 is stripped and only the microlenses 125 remain on the top surface of the organo-silane adhesive layer 110.

Thereafter, as shown in FIG. 1D, a soluble amorphous fluoropolymer (Teflon AF, trade name) is dissolved in a fluorinated solvent (Fluorinert, 3M) on the first substrate 100. Spin coat the solution.

Thereafter, the solvent is volatilized to obtain a hard flat thin film. Hereinafter, the hard flat thin film will be defined as a "flat film" and will be referred to by reference numeral 140.

The thin film transistor 150 is fabricated on the upper surface of the light refraction pattern layer 135 manufactured as described above, as shown in FIG. 1E.

In this case, the thin-film transistor 150 is formed on the upper surface of the light refraction pattern layer 135 because the reflective-transmissive liquid crystal display device according to an embodiment of the present invention is an active type, but in the case of a passive reflective-transmissive liquid crystal display device, The thin film transistor 135 is formed outside.

In the method of manufacturing the thin film transistor 135, first, a gate thin film is formed on the top surface of the flat film 140, and then the gate thin film is patterned to form the gate electrode 142.

Subsequently, the gate insulating layer 144, the active pattern 146, and the source / drain metal are sequentially deposited on the top surface of the gate electrode 142, and then the source / drain metal is patterned to form the source electrode 147 and the drain electrode 148. ) Is formed.

In this case, the thin film transistor 150 having such a configuration does not overlap with the micro lens 125 of the light refractive pattern layer 135 that is already formed.

To this end, the thin film transistor 150 is formed on the upper surface of the flat film 140 corresponding to the valley between the microlens 125 of the light refraction pattern layer 135 and the tip of the adjacent microlens 125.

Thereafter, as illustrated in FIG. 1F, an organic insulating layer 160 is coated on the entire surface of the first substrate 100 over the entire surface.

In this case, the coating thickness of the organic insulating layer 160 is closely related to the brightness of light, and thus, a more specific coating thickness of the organic insulating layer 160 will be described together with the reflection electrode and the transmission electrode which will be described later in detail.

A contact hole 165 is formed in the organic insulating layer 160 formed on the first substrate 100 to expose the drain electrode 148 of the thin film transistor 150 disposed under the organic insulating layer 160.

Meanwhile, when forming the contact hole 165, the concave-convex 167 is formed on the upper surface of the organic insulating layer 160 so that external light can be sufficiently diffused when the display is performed in the reflective mode.

Thereafter, as illustrated in FIG. 1G, a transmissive electrode 170 is formed of an ITO material or an IZO material on the upper surface of the organic insulating layer 160 on which the contact holes 165 and the unevenness 167 are formed, and the transmissive electrode 170 is formed. The reflective electrode 180 is formed on the upper surface of the aluminum and aluminum alloy material again.

In this case, the reflective electrode 180 reflects the external light to perform the display, and the transmissive electrode 170 transmits the light supplied from the lower portion of the first substrate 100 to the organic insulating layer 160 to perform the display. To help.

To this end, a portion of the reflective electrode 180 is opened to expose a portion of the transmissive electrode 170 positioned below the reflective electrode 180 from the reflective electrode 180.

In this case, the opening of the reflective electrode 180 is aligned with the microlens 125 of the light refraction pattern layer 135 that is already formed so that the light collected from the microlens 125 is formed in the reflective electrode 180. 185).

In this case, after the light is collected from the microlens 125, the luminance of the light emitted through the opening 185 formed in the reflective electrode 180 is equal to the separation distance between the reflective electrode 180 and the microlens 125. Is determined by.

Specifically, as shown in graph a of FIG. 2, the gap between the reflective electrode 180 and the microlens 125 must be equal to or smaller than the pitch of the microlens 125 so that the opening 185 of the reflective electrode 180 is formed. The brightness of the light emitted from the? Can be maximized.

At this time, when the distance between the reflective electrode 180 and the microlens 125 is larger than the width of the microlens 125, the luminance is reduced as shown in the graph b.

In this case, the distance between the reflective electrode 180 and the microlens 125 is related to the thickness of the organic insulating layer 160, so that the luminance of the light emitted from the opening 185 of the reflective electrode 180 is the maximum as described above. The thickness of the organic insulating layer 160 is adjusted to be precise.

Subsequently, as illustrated in FIG. 1H, the second substrate 210 having the RGB pixel 200 and the common electrode 190 is assembled on the top surface of the first substrate 100.

Subsequently, the reflection-transmissive liquid crystal display 230 is manufactured by injecting a liquid crystal 220 that adjusts light transmittance between the first substrate 100 and the second substrate 210 according to the intensity of the electric field.

As described in detail above, it is possible to perform the display by consuming electric energy in a place where the amount of light is insufficient, and to perform the display with the minimum power consumption by performing the display using external light in a place where the amount of light is abundant. When performing the display in a place where the amount of light is insufficient, greatly improve the display performance by improving the display performance, as well as has the effect of performing a high-quality display with low power consumption.

Claims (8)

A first substrate; A light refracting pattern layer having a plurality of micro lenses formed on the first substrate at a first pitch interval and continuously formed to collect light; Thin film transistors formed between the front end portions of the micro lenses and having drain electrodes formed thereon; An organic insulating layer formed on an upper surface of the first substrate to have a thickness less than or equal to the first pitch and having an opening exposing the drain electrodes; Transmission electrodes formed to be electrically connected to drain electrodes of the thin film transistors; Reflective electrodes formed on upper surfaces of the transmissive electrodes and having an opening window through which light collected by the microlenses passes; A second substrate provided to face the first substrate; And And a liquid crystal formed between the first substrate and the second substrate. The method of claim 1, wherein a flat film is formed on an upper surface of the light refractive pattern layer, the light refractive pattern layer has a refractive index of 1.48-1.56, the flat film has a refractive index of 1.31-1.35 Transmissive liquid crystal display device. The reflection-transmissive liquid crystal display device according to claim 1, wherein the separation distance between the reflective electrode and the light refraction pattern layer is the same as the first pitch. The reflection-transmissive liquid crystal display device according to claim 1, wherein an interval between the light refraction pattern layer and an aperture window are the same. Iii) forming a light refracting pattern layer on the first substrate having a plurality of micro lenses formed on the first substrate at a first pitch interval to condense light; Ii) forming thin film transistors formed between the tips of the micro lenses, each having a drain electrode formed thereon; Iv) forming an organic insulating layer having a thickness less than or equal to the first pitch on an upper surface of the first substrate, and forming contact holes to expose the drain electrodes in the organic insulating layer; Iii) forming transmissive electrodes to be electrically connected with the drain electrodes; Iii) forming reflective electrodes on the upper surfaces of the transmissive electrodes, the apertured window through which the light collected by the micro lens passes; Iii) providing a second substrate to face the first substrate; And Iii) injecting a liquid crystal between the first substrate and the second substrate. The method of claim 5, wherein the forming of the light refractive pattern layer comprises: applying an adhesive layer to the first substrate; Applying a photoreactive monomer having a first refractive index to an upper surface of the adhesive layer; Pressing the photoreactive monomer such that the profile has a prism shape and a first pitch; Scanning the cured photoreactive monomer with light to form a first photorefractive pattern; And And forming a flat film having a second refractive index on the upper surface of the first light refraction pattern. The method of claim 5, wherein the separation distance between the reflective electrode and the light refraction pattern layer is the same as the first interval. The method of manufacturing a reflection-transmissive liquid crystal display device according to claim 5, wherein the formation position of the opening window coincides with the formation position of the light refraction pattern layer.