KR100713886B1 - A transflective liquid crystal display and method for fabricating the same - Google Patents

Abstract

The present invention discloses a transflective liquid crystal display and a method of manufacturing the same. The disclosed invention comprises an array substrate, a color filter substrate disposed with a predetermined cell gap with the array substrate, and a liquid crystal layer filled therebetween, wherein the array substrate forms a horizontal electric field with a reflector forming a vertical electric field. A resin film formed over the reflecting portion and the transmitting portion, the reflecting plate disposed on the resin film on the reflecting portion, and a lower alignment film formed over the resin film on the reflecting plate and the transmitting portion; The color filter substrate is disposed above the array substrate, the color filter substrate is formed on a first color pigment layer and a transparent electrode stacked on a surface facing the reflecting portion of the array substrate, and is formed on a portion facing the transmissive portion. A second color pigment layer thicker than the color pigment layer, and an upper alignment film formed on the transparent electrode and the second color pigment layer.

Description

A transflective liquid crystal display and method for fabricating the same

1 is a cross-sectional view of a liquid crystal display device having a configuration in which a step is formed on an array substrate in a liquid crystal display device according to an embodiment of the prior art;

2 is a cross-sectional view showing a liquid crystal display device having a step formed on a color filter substrate in a liquid crystal display device according to another embodiment of the prior art;

3 is a diagram illustrating a structure of a transflective liquid crystal display device according to the present invention and polarization states of respective portions (a) is a state when voltage is off, and (b) is a state when a threshold voltage is applied. ,

4 is an embodiment in which the polarization displacement of each mode is drawn on the Poangcurry sphere in order to easily see the movement of the polarization in the cell in the transflective liquid crystal display according to the present invention, and FIG. Is a diagram illustrating the shift of polarization at the voltage off in

Figure 4 (b) is a view showing the polarization mobility of the reflection / transmission portion when the voltage is on.

[Description of Drawing Reference]

101: array substrate 103: resin film

105: reflector plate (reflective electrode) 107: lower alignment film

109: phase delay film 111: lower polarizing plate

121: liquid crystal layer 131: color filter substrate (upper substrate)

133a: first color pigment layer 133b: second color pigment layer

135 transparent electrode 137 upper alignment layer

139: upper polarizing plate

The present invention relates to a transflective liquid crystal display and a method for manufacturing the same. More specifically, in relation to the mode design of the transflective liquid crystal display, a transverse electric field mode is used as a transmission mode, and an ECB mode is used as a reflection mode. The present invention relates to a transflective liquid crystal display device and a method for manufacturing the same, which simplify the manufacturing process and widen the viewing angle by making the cell gaps on both the transmissive part and the reflective part equal.

The semi-transmissive liquid crystal display device has a reflection mode driving by ambient light and a transmission mode driving by a back light source.

In this respect, examples of existing transflective LCD structures for different gap formation of the reflecting and transmitting portions are described in FIGS. 1 and 2. 1 illustrates an example of Korean Patent 10-2000-0018321 as one embodiment of the prior art, and the prior patent has a configuration in which a step is formed on an array substrate. In addition, Fig. 2 shows a structure in which a step is formed on the color filter side as another embodiment of the prior art.

Referring to Figures 1 and 2 with respect to the configuration of the prior art as follows.

1 is a cross-sectional view of a liquid crystal display device having a configuration in which a step is formed on an array substrate in a liquid crystal display device according to an embodiment of the prior art, and FIG. 2 is a liquid crystal display device according to another embodiment of the prior art. Is a cross-sectional view showing a liquid crystal display device having a step formed on a color filter substrate.

The liquid crystal display according to the exemplary embodiment of the prior art includes an upper substrate 11 and a lower substrate 31 arranged at regular intervals and a liquid crystal layer 23 filled in a space therebetween. Here, the upper substrate 11 is the upper polarizing plate 15 laminated on the first transparent glass substrate 13 and the color pigment layer 17 and the first protective layer laminated on the rear surface of the first transparent glass substrate 13. It is composed of a layer 19 and a first common electrode 21.

In addition, the first protective layer 19 has a groove (not shown) of a predetermined depth in the center to maintain a constant step with the edge portion.

The lower substrate 31 includes a pixel electrode 35 stacked on the second transparent glass substrate 33, a second protective layer 37 stacked on the pixel electrode 35 at a predetermined interval, and The lower common polarizing plate 41 and the light guide plate are stacked on the second common electrode 39 and the lower surface of the second transparent glass substrate 33.

Here, the cell gap between the central portion of the first common electrode 19 and the pixel electrode 35 facing the first common electrode 19 is “2d”, and the edge portion of the first common electrode 19 is opposite to the edge portion of the first common electrode 19. The cell gap between the second common electrodes 39 is "d".

On the other hand, the liquid crystal display device according to another embodiment of the prior art, as shown in Figure 2, is composed of an upper substrate 51 and the lower substrate 71 and the liquid crystal layer 61 filled between them.

Here, the transparent resin layer 53 is formed on one side of the lower surface of the upper substrate 51, and the color filter layer 55 is formed on the lower surface of the upper substrate 51 including the transparent resin layer 53.

In addition, a transistor unit 73 is formed on one side of the lower substrate 71, and a storage capacitor electrode 75 is formed on the other side of the lower substrate 71 facing the transparent resin layer 53. The insulating layer 77 and a transparent electrode 79 are formed on the lower substrate 71 including the transistor unit 73 and the capacitor electrode 75 with a predetermined distance therebetween.

In addition, a reflective electrode 81 is formed at a portion of the transparent electrode 79 at a position opposite to the transparent resin layer 53. Here, the cell gap between the portion of the color filter 55 and the transparent electrode 79 formed in a region other than the portion of the transparent resin layer 53 is "2d", and the portion of the color filter 55 on the transparent resin layer 53 The cell gap between the reflecting electrodes 79 is "d".

According to the prior art as described above, due to the coexistence of reflection and transmission, the pigment thickness of each of the reflection part and the transmission part of the color filter must be designed differently, and the cell gap must also be doubled in the same driving mode. This is a problem caused by the light having to consider two passes along the reflection in the reflector.

Moreover, this cell structure is very difficult in the manufacturing process because the thicknesses of the surface of the film in the cell must be made very different.

Therefore, in order to avoid this, many studies such as the selection of a driving mode and a manufacturing method have been conducted, but it is difficult to avoid problems such as reflection and transmission mode reversal problems and large amounts of phase delay films.

Accordingly, the present invention has been made in order to solve the above problems of the prior art, select the mixed drive mode that can achieve the difficulty of the manufacturing process according to the driving conditions of the reflection, transmission, and at the same time to achieve a minimum film use and a transflective wide viewing angle Accordingly, an object of the present invention is to provide a transflective liquid crystal display device and a method of manufacturing the same, which can realize a low-cost low-power type and portable display.

A semi-transmissive liquid crystal display device according to the present invention for achieving the above object, in the transflective liquid crystal display device, comprising an array substrate, a color filter substrate having a predetermined cell gap with the array substrate and a liquid crystal layer filled therebetween. The array substrate is divided into two regions of a reflecting portion forming a vertical electric field and a transmitting portion forming a horizontal electric field, wherein the resin film is formed on the reflecting portion and the transmitting portion and disposed on a resin film on the reflecting portion. A reflecting plate, and a lower alignment film formed over the reflecting plate and the resin film on the transmission portion; The color filter substrate is disposed on an upper side opposite to the array substrate, the first color pigment layer and a transparent electrode stacked on a surface facing the reflecting portion of the array substrate, and formed on a portion facing the transmissive portion and formed on the first color. And a second color pigment layer thicker than the pigment layer, and an upper alignment layer formed on the transparent electrode and the second color pigment layer.

In addition, the method for manufacturing a transflective liquid crystal display device according to the present invention includes the steps of: preparing an array substrate and a color filter substrate having a predetermined cell gap with the array substrate; Dividing the array substrate into two regions of a reflecting portion forming a vertical electric field and a transmitting portion forming a horizontal electric field; Forming a resin film over the reflecting portion and the transmitting portion of the array substrate; Forming a reflector on the resin film of the reflector; Forming a lower alignment layer on the reflecting plate and the resin layer of the transmission unit; Arranging a color filter substrate on an opposite side of the array substrate, the first color pigment layer and a transparent electrode stacked on a surface of the array substrate facing the reflector; Forming a second color pigment layer thicker than the first color pigment layer in a portion facing the transmission part; Forming an upper alignment layer on the transparent electrode and the second color pigment layer; And filling the liquid crystal layer between the array substrate and the color filter substrate.

(Example)

Hereinafter, a transflective liquid crystal display device and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

In the transflective liquid crystal display according to the present invention, as shown in FIG. 3, the array substrate 101 is divided into two regions, a reflecting portion B for forming a vertical electric field and a transmissive portion A for forming a horizontal electric field. The resin layer 103, the transparent electrode 105, and the lower alignment film 107 are formed in both regions.

In addition, the color filter substrate 131 is arranged on the upper side facing the array substrate 101, the light blocking film (not shown) on one surface of the color filter substrate (not shown) facing the alignment layer 137 of the array substrate 101 Is patterned, and first and second color pigment layers 133a and 133b and an upper transparent electrode 135 are formed thereon.

In the meantime, a manufacturing method of the transflective liquid crystal display device having the above configuration will be described.

First, the reflective portion A of the array substrate 101 patterns the resin layer 103 to have an all-convex rough surface.

Subsequently, the reflective electrode is coated on the transparent electrode 105 to form a pixel electrode, and the transmission part B patterns the pixel electrode to form a lateral electric field mode horizontal electric field with the lower common electrode.

Subsequently, the alignment layer 107 is coated on the pixel electrode and rubbed for alignment, but the rubbing direction is about 90 ° to the horizontal electric field direction.

On the other hand, the color filter substrate 131 is arranged on the upper side facing the array substrate 101, the light blocking film (not shown) on one surface of the color filter substrate (not shown) facing the alignment layer 137 of the array substrate 101 After patterning), the first and second color pigment layers 133a and 133b and the upper transparent electrode 135 are stacked thereon. In this case, the thickness of the second color pigment layer 133b positioned in the transmission portion B is about twice as high as that of the first color pigment layer 133a positioned in the reflection portion A.

In addition, the transparent electrode 135 is formed only on the low first color pigment layer 133a of the reflecting portion A generated thereby, and is transparent so that there is no difference in thickness between the reflecting portion A and the transmitting portion B. A film (not shown) is formed.

Next, the upper alignment layer 137 is coated and rubbed on the transparent layer (not shown), and parallel to the rubbing direction of the lower alignment layer 107 on the side of the array substrate opposite to the other side of the color filter substrate 131. An upper polarizing plate 139 is attached to the upper polarizing plate 139, and its transmission axis lies between the rubbing direction and the horizontal electric field of the array substrate 101, respectively, to form 45 °.

The transflective liquid crystal display according to the present invention forms a normally black state by driving the ECB mode in the reflector A. FIG.

Here, in the reflection mode, even when the liquid crystal 121 stands at an arbitrary pretilt angle, the ECB mode is easy to drive and has little afterimage in view of the fact that the left and right and up and down sides are symmetrically transmissive.

In addition, in the transmission part B, since the viewing angle is dependent, a field fringe sequance (FFS) mode is used in the transmission area, which is a wide viewing angle and can easily serve as a 1/4 wavelength phase plate due to liquid crystal distortion.

3 shows an example of the structure of the transflective liquid crystal display according to the present invention and polarization states of respective parts, (a) shows a state when voltage is off, and (b) shows a state when a threshold voltage is applied. .

As shown in FIG. 3 (a), in the normal state without voltage, both the reflecting portion A and the transmitting portion B have 45 ° of the liquid crystal alignment due to the transmission axis direction of the upper polarizer 139 and the rubbing of the upper substrate. Therefore, by the quarter-wave phase delay cell, the reflection portion A changes the horizontal polarization to the left circular polarization, and after reflection, the right circular polarization becomes vertical linear polarization again to form dark.

In addition, the transmissive portion B is the light incident from the lower side of the right circular polarization made of a quarter phase film 109 is vertically polarized by the cell to form a dark.

On the other hand, as shown in (b) of FIG. 3, when the driving voltage Vo is applied, the reflector A has the liquid crystal 121 completely standing up so that the light transmitted through the transmission axis of the upper polarizer 139 remains in its polarized form. It is transmitted and reflected, and exits the transmission axis of the upper axis polarizing plate 139 again.

In addition, the transmissive part B realizes height because the right circularly polarized light enters the liquid crystal 121 and undergoes a phase delay according to the twisted liquid crystal array and becomes horizontal linearly polarized light.

4 is an embodiment in which the polarization displacement of each mode is drawn on the Poangcurry sphere in order to easily see the movement of the polarization in the cell in the transflective liquid crystal display according to the present invention, and FIG. The polarization shift at the time of the voltage off in the above description is explained. When the reflection is performed, the light horizontally polarized by the upper polarizing plate becomes the left circularly polarized light rotated by 90 ° by the biaxial 45 ° tilted liquid crystal, and the right circularly polarized light by mirror reflection. Is rotated 90 degrees by the mirror-symmetrical 45-degree liquid crystal (-) 2 axis to become a vertical linearly polarized light, which is all absorbed by the upper polarizer.

In addition, the light incident to the right circularly polarized light by the quarter-wave phase film 109 from the lower side during transmission becomes vertical linearly polarized light by experiencing a negative polarization liquid crystal as in the case of reflection, and thus is applied to the upper polarizer 139. Are absorbed by all.

On the other hand, Figure 4 (b) shows the polarization mobility of the reflection / transmissive portion when the voltage is on, the liquid crystal 121 is all standing vertically when the voltage of the reflector (A) is on state As it passes through as it is, there is no change in polarization. In the transmissive portion B, a liquid crystal 121 forms a pseudo TN mode in which the liquid crystal 121 is twisted by 90 ° under the mutual influence of the alignment due to the alignment film 137 and the electric field. Since the light coincides with the horizontal direction of the transmission axis of the upper polarizing plate 139, a considerable amount is transmitted.

As described above, the structure of the transflective liquid crystal display according to the present invention increases the efficiency of the reflection angle by coating a resin on the array substrate and forming a convex pattern.

On the other hand, as another embodiment of the present invention, by forming a diffusion plate on the black matrix of the color filter substrate, it is possible to widen the bandwidth of the reflection angle.

As described above, according to the transflective liquid crystal display device and the manufacturing method thereof according to the present invention, since the cells of the reflecting portion and the transmitting portion all have the same or slightly different cell gap so as to be a quarter-wavelength phase delay cell, The manufacturing process according to rubbing is easy and transverse driving mode uses transverse electric field mode, so it can be applied to a wide range of display fields such as large TVs requiring wide viewing angles, displays requiring high contrast for the surrounding environment, and low-power displays. .

In addition, since the materials are the same except that the 1/4 wavelength retardation film is required as compared to the conventional transmissive liquid crystal display devices, the cost can be reduced compared to the transflective liquid crystal display devices requiring much of the phase film.

On the other hand, the present invention is not limited to the above-described specific preferred embodiments, and various changes can be made by those skilled in the art without departing from the gist of the invention claimed in the claims. will be.

Claims (11)

In the transflective liquid crystal display device, It comprises an array substrate and the color filter substrate and a liquid crystal layer filled between the array substrate and a predetermined filter cell gap, The array substrate is divided into two regions, a reflecting portion forming a vertical electric field and a transmitting portion forming a horizontal electric field. A resin film formed on the reflecting portion and the transmitting portion, A reflector disposed on the resin film on the reflector, and A lower alignment film formed over the reflecting plate and the resin film on the transmission portion; The color filter substrate is disposed above the array substrate, the first color pigment layer and the transparent electrode stacked on a surface facing the reflecting portion of the array substrate, A second color pigment layer formed at a portion facing the transmission portion and thicker than the first color pigment layer, and And a top alignment film formed on the transparent electrode and the second color pigment layer. The film according to claim 1, wherein a quarter phase film is attached to the other surface of the array substrate opposite to the bottom alignment film surface, and a lower polarizing plate having a transmission axis at 45 ° is attached to the fast axis of the film. Semi-transmissive liquid crystal display device. The semi-transmissive liquid crystal display device according to claim 1, wherein the liquid crystal filled between the array substrate and the color filter substrate is a positive liquid crystal. The semi-transmissive liquid crystal display device according to claim 1, wherein the thickness of the second color pigment layer is twice the thickness of the first color pigment layer. The transflective liquid crystal display device according to claim 1, wherein the surface of the reflecting plate is irregular. The transflective liquid crystal display device according to claim 1, wherein a diffusion plate is further attached on the transparent electrode on the color filter substrate. In the manufacturing method of the transflective liquid crystal display device, Preparing an array substrate and a color filter substrate having a predetermined cell gap with the array substrate; Dividing the array substrate into two regions of a reflecting portion forming a vertical electric field and a transmitting portion forming a horizontal electric field; Forming a resin film over the reflecting portion and the transmitting portion of the array substrate; Forming a reflector on the resin film of the reflector; Forming a lower alignment layer on the reflecting plate and the resin layer of the transmission unit; Arranging a color filter substrate on an opposite side of the array substrate, the first color pigment layer and a transparent electrode stacked on a surface of the array substrate facing the reflector; Forming a second color pigment layer thicker than the first color pigment layer in a portion facing the transmission part; Forming an upper alignment layer on the transparent electrode and the second color pigment layer; And A method of manufacturing a transflective liquid crystal display device, comprising: filling a liquid crystal layer between the array substrate and the color filter substrate. 8. The method of claim 7, further comprising sequentially attaching a quarter phase film to the other surface opposite to the lower alignment layer surface of the array substrate and a lower polarizing plate having a transmission axis at 45 ° to the fast axis of the film. A semi-transmissive liquid crystal display device manufacturing method characterized in that. 8. The method of claim 7, wherein the liquid crystal filled between the array substrate and the color filter substrate is a positive liquid crystal. The method of manufacturing a transflective liquid crystal display device according to claim 7, wherein the thickness of the second color pigment layer is twice the thickness of the first color pigment layer. 8. The method of claim 7, wherein the surface of the reflector is formed in an uneven shape.

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