KR20060032423A - Method manufacturing of color filter substrate and liquid crystal display having the same - Google Patents

Abstract

Disclosed are a manufacturing method of a color filter substrate for improving a production rate, and a liquid crystal display device having the same. The liquid crystal display device includes a first substrate, a second substrate, and a liquid crystal layer. The first substrate has a plurality of pixel portions having a reflection region and a transmission region, and the second substrate has a color pixel layer, and a step is formed corresponding to the reflection region and the transmission region. The liquid crystal layer is formed between the first substrate and the second substrate, the phase retardation layer is formed on the second substrate corresponding to the reflective region, and compensates for the phase difference of light passing through the liquid crystal layer. Thereby, production yield and transmittance can be improved by forming a phase retardation layer in a liquid crystal cell.

Phase delay layer, transmittance, retardation compensation

Description

TECHNICAL MANUFACTURING COLOR FILTER SUBSTRATE AND LIQUID CRYSTAL DISPLAY HAVING THE SAME

1 is a cross-sectional view illustrating a general reflection-transmissive liquid crystal display device.

2 is a cross-sectional view for describing a liquid crystal display device according to an exemplary embodiment of the present invention.

FIG. 3 is a diagram for schematically describing a molecular structure of a cholesteric liquid crystal, which is an example of the phase delay layer of FIG. 2.

4A to 4D are process diagrams for describing the method of manufacturing the color filter substrate of FIG. 2.

<Description of Symbols for Main Parts of Drawings>

100: array substrate 200: color filter substrate

201: transparent substrate 202: light shielding layer

203: Color layer 204: Insulation layer

206: phase delay layer 207: common electrode layer

The present invention relates to a method for manufacturing a color filter substrate and a liquid crystal display device having the same, and more particularly, to a method for manufacturing a color filter substrate for improving the production rate and a liquid crystal display device having the same.

In general, since reflective type LCDs use natural light incident from the outside, the display becomes dark due to a decrease in the amount of light in a dark place, so that the displayed image cannot be properly viewed. In addition, since a transmissive type LCD uses artificial light incident from a device such as a backlight, the transmissive type LCD can recognize the displayed image regardless of a bright or dark place, but the power consumption is increased by the amount of the light source. In particular, there is a disadvantage that it is not suitable for a portable display device operated by a battery.

In order to solve these drawbacks, there is a transflective liquid crystal display (Trans-Reflective type LCD) that uses the above-described reflective liquid crystal display and the transmissive liquid crystal display.

1 is a cross-sectional view illustrating a general reflection-transmissive liquid crystal display device.

Referring to FIG. 1, a general reflection-transmissive liquid crystal display device includes an array substrate 10 having a reflector plate 19 defining a reflecting region and a transmitting region 19a, and a color filter substrate facing the array substrate 10. (20), the liquid crystal layer 30 formed between the array substrate 10 and the color filter substrate 20, the upper? / 4 phase retardation film 40 disposed on the color filter substrate 20, and the upper polarizing plate ( Polarizer 50, a lower λ / 4 phase retardation film 60 disposed below the array substrate 10, and a lower polarizer 70.                         

In the conventional reflection-transmissive liquid crystal display device, the cost of the display panel is increased by using an expensive phase retardation film, and the production yield of the array substrate is reduced by forming a double step on the array substrate. In addition, in the transmissive mode, the incident light passes through the phase retardation film twice unnecessarily, so that the transmittance is lowered.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a manufacturing method of a color filter substrate for improving the production yield.

An object of the present invention is to provide a liquid crystal display device having the color filter substrate.

In the manufacturing method of the color filter substrate for a liquid crystal display device which accommodates a liquid crystal layer through the coalescing of the array substrate in which the pixel part which has the reflective area and the transmission area | region formed according to the Example for realizing the above objective of this invention is (a) forming a color pixel layer on the substrate, (b) forming an insulating layer on the color pixel layer, and (c) removing the insulating layer corresponding to the transmission area to remove the reflection area and transmission. Forming a step corresponding to the region, (d) forming a phase delay layer on the insulating layer corresponding to the reflective region, and (e) forming a common electrode layer on the substrate on which the phase delay layer is formed. Include.                     

A liquid crystal display according to an embodiment for realizing another object of the present invention includes a first substrate, a second substrate, and a liquid crystal layer. The first substrate has a plurality of pixel portions having a reflection region and a transmission region, and the second substrate has a color pixel layer, and a step is formed corresponding to the reflection region and the transmission region. The liquid crystal layer is formed between the first substrate and the second substrate, the phase delay layer is formed on the second substrate corresponding to the reflecting portion, and compensates for the phase difference of light passing through the liquid crystal layer.

The liquid crystal display further includes a first polarizing plate for first polarizing light incident on the first substrate, and a second polarizing plate for second polarizing light emitted from the second substrate.

Preferably, a first cell gap of the liquid crystal layer corresponding to the reflective region and a second cell gap of the liquid crystal layer corresponding to the transmission region are different, and the first cell gap is smaller than the second cell gap.

Preferably, the second substrate further includes an insulating layer formed on the color layer corresponding to the reflective region, and the phase delay layer is formed on the insulating layer. Even more preferably the phase retardation layer is formed of a liquid crystalline polymer material.

According to the manufacturing method of the color filter substrate and the liquid crystal display device having the same, the production cost is reduced by reducing the phase retardation film, and the optical retardation is improved in the transmissive mode by forming the phase retardation film corresponding to the reflective region. You can.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention.                     

2 is a cross-sectional view for describing a liquid crystal display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the liquid crystal display includes an array substrate 100, a color filter substrate 200, a liquid crystal layer 300 interposed between the array substrate 100 and the color filter substrate 200. , A front polarizer 410, and a rear polarizer 420.

The array substrate 100 includes a gate wiring, a data wiring, and a thin film transistor connected to the data wiring and the scan wiring on the transparent substrate 101. Specifically, a gate wiring and a gate electrode of the thin film transistor TFT are formed on the transparent substrate 105 as a gate metal layer, and a gate insulating layer is formed on the gate metal layer. The channel layer of the thin film transistor TFT is formed. A source electrode and a drain electrode of the data line and the thin film transistor TFT are formed of source and drain metal layers, and a passivation layer is formed on the source and drain metal layers.

As described above, when the insulating layer 103 including the gate insulating layer and the passivation layer is formed on the transparent substrate 105, a contact hole is formed in the insulating layer 103 to expose a portion of the drain electrode. Form. A pixel electrode layer 105 patterned in pixel units P is formed on the insulating layer 103, and the pixel electrode layer 105 and the drain electrode are electrically connected by the contact hole.

A reflective plate 107 is formed on the pixel electrode layer 105 to partition the reflective region R and the transparent region T. That is, the region in which the reflector plate 107 is formed is the reflective region R, and the other region is the transmission region T. Preferably, a protective layer is formed on the pixel electrode layer 105 on which the reflective plate 107 is formed, and an alignment layer is formed on the array substrate on which the pixel electrode layer 105 and the reflective plate 107 are formed.

The color filter substrate 200 includes a color pixel layer 203, an insulating layer 204, a phase delay layer 206, and a common electrode layer 207 on the transparent substrate 201.

The color pixel layer 203 includes red, green, and blue color pixel layers R, G, and B corresponding to the pixel area P. FIG. Light holes 203h are formed in the red, green, and blue color pixel layers R, G, and B, respectively. The light hole 203h compensates for a difference in luminance between the transmission region T and the reflection region R. FIG.

The insulating layer 204 is patterned to have a step corresponding to the reflective region R and the transparent region T. FIG. That is, the insulating layer 204 of the transmission region T is etched, and the insulating layer 204 of the reflection region R is patterned to remain.

The phase retardation layer 206 is formed on the insulating layer 204 formed in the reflective region to retard the phase of light passing through the liquid crystal layer 300. The phase retardation layer 206 is a coatable liquid crystal polymer layer. Preferably, the UV curable liquid crystal polymer material is, for example, a cholesteric liquid crystal.

Even more preferably, the retardation value of the phase retardation layer 206 is 100 to 160 nm, and the sum of the thicknesses of the insulating layer 204 and the phase retardation layer 206 is 1.0 to 2.0 μm.

Specifically, the phase retardation layer 206 is formed of a UV curable liquid crystal polymer material, and is preferably a cholesteric liquid crystal as shown in FIG. 3. 3 is a view for schematically explaining the molecular structure of the cholesteric liquid crystal.                     

As shown in Figure 3, the director changes gradually along the helical axis. This helical structure is characteristic of the cholesteric phase with its rotation period p. And this spiral axis coincides with the optical axis. That is, when a chiral structure in which the mirror symmetry is broken in the molecular structure among the molecules forming the nematic phase is shown, the nematic phase of the spiral structure may be displayed, which is called cholesteric liquid crystal. Locally, the cholesteric liquid crystal is characterized in that the liquid crystal molecules are directed in one direction, such as nematic, but macroscopically has a spiral axis perpendicular to the director, and the director is constantly rotated about this axis.

Biaxial film by coating and orienting the cholesteric liquid crystal to a predetermined thickness on the insulating layer 204 of the reflective region (R) and fixing the alignment state of the cholesteric liquid crystal by irradiating UV light. A phase retardation layer having a) function or a uniaxial film function is formed.

For example, a biaxial film is formed by irradiating polarized UV light to the cholesteric liquid crystal, and a C-plate film is formed by irradiating non-polarized UV light to the cholesteric liquid crystal. The biaxial film has a refractive index characteristic in which the refractive index nx in the x direction, the refractive index ny in the y direction, and the refractive index nz in the z direction are different from each other.

Meanwhile, the uniaxial film is classified into an A-plate film and a C-plate film. The A-plate film has the same refractive index ny in the y direction and the refractive index nz in the z direction, but has a refractive index characteristic smaller than the refractive index nx in the x direction.

When the C-plate film has UV-curable liquid crystals having the refractive index characteristics of the A-plate film irregularly arranged on the xy plane and has a thickness, the UV-curable liquid crystal has a refractive index (nx) in the x direction and a refractive index in the y direction ( ny) is the same, but has a refractive index characteristic larger than the refractive index nz in the z direction.

The common electrode layer 207 is formed on the phase retardation layer 206 formed in the reflection region R and on the color pixel layer 203 of the transmission region T. The common voltage VCOM is applied to the common electrode layer 207 from the outside. In addition, an alignment layer is preferably formed on the common electrode layer 207.

The liquid crystal layer 300 is formed between the array substrate 100 and the color filter substrate 200, and the common electrode layer 207 of the pixel electrode layer 105 and the color filter substrate 200 of the array substrate 100. Answer by the potential difference applied between The liquid crystal layer 300 may adopt a twist nematic (TN) mode, a vertical alignment (VA) mode, or may employ an OCB (Optically Compensated Birefringence) mode. Preferably, the TN mode in which the twist angle of the liquid crystal molecules is in the range of 0 to 90 degrees is adopted. The liquid crystal layer 300 has the cell gap between the reflective region R and the liquid crystal layer corresponding to the transmission region T. Here, the first cell gap d1 of the reflective region R and the second cell gap d2 of the transmission region T satisfy a condition of d1 <d2. Preferably, the first cell gap d1 is 1.0 μm to 2.5 μm, and the second cell gap d2 is 2.0 μm to 5.0 μm.

In particular, when the anisotropic refractive index of the liquid crystal molecules constituting the liquid crystal layer 300 is Δn and the cell gap is d, the liquid crystal layer 300 of the reflective region R has a characteristic of Δnd1, and the transmission The liquid crystal layer 300 in the region T has a characteristic of Δnd2.

Optimal cell gaps for the reflective region R and the transmission region T depend on the liquid crystal molecules forming the liquid crystal layer 300 or the conditions of the optical film provided on both upper and lower sides of the liquid crystal layer 300. However, the cell gap d1 corresponding to the reflection area is smaller than the cell gap d2 corresponding to the transmission area. Preferably, the cell gap corresponding to the reflection area is about 1/2 of the cell gap corresponding to the transmission area.

The rear polarizer 410 is disposed below the array substrate 100 to provide first polarized artificial light provided from the rear surface to the array substrate 100.

The front polarizer 420 is disposed on the color filter substrate 200 to emit the second polarized light through the array substrate 100, the liquid crystal layer 300, and the color filter substrate 200.

4A to 4D are manufacturing process diagrams for describing a method of manufacturing the color filter substrate of FIG. 2.

Referring to FIG. 4A, a light blocking layer 202 is formed on the transparent substrate 201. The light blocking layer 202 is formed by forming a chromium (Cr) film and patterning it using a photoresist mask. The light blocking layer 202 is formed in a lattice shape on the transparent substrate 201 in correspondence with a gate line and a data line formed on an array substrate incorporating a color filter substrate.

Subsequently, a photosensitive red resist is applied, exposed and developed on the transparent substrate 201 on which the light shielding layer 202 is formed to form a red pixel layer 203R in a predetermined selected region. In the same manner, the green and blue resists are applied, exposed and developed to form the green color layer 203G and the blue color layer 203B in a predetermined selected area. A light hole 203h is formed in the color layer 203 to compensate for the luminance of the reflective region R with respect to the transmission region T. The light hole 203h is formed corresponding to the reflective region R of the array substrate 100.

Referring to FIG. 4B, a thick insulating layer 204 is formed on the color pixel layer 203, and the insulating layer 204 corresponding to the transmission region T is removed using the photoresist pattern 210 as a mask. do. As a result, the transmission region T and the reflection region R are formed to have a step difference, and the step difference is a cell gap of the liquid crystal layer of the transmission region T and a cell gap of the liquid crystal layer of the reflection region R. Form differently.

Referring to FIG. 4C, a UV curable liquid crystalline polymer material such as cholesteric liquid crystal is coated and oriented on the insulating layer 204 of the reflective region T. The alignment state is fixed through irradiation of UV light to form a phase delay layer 206 having a phase difference function.

If the UV light is polarized UV light, the phase retardation layer 206 has a biaxial film function, and if the UV light is non-polarized UV light, the phase retardation layer 206 has a C-plate film function. As a result, a phase delay layer 206 is formed on the insulating layer 204 of the reflective region R. FIG.

Referring to FIG. 4D, the common electrode layer 207 is formed by forming a transparent conductive layer such as ITO on the front surface of the color filter substrate 200 on which the phase delay layer 206 is formed. Although not shown, an alignment layer is formed on the common electrode layer 207 so that the liquid crystals are arranged in a predetermined direction.

Through the process of FIGS. 4A to 4D described above, the color filter substrate 200 is completed, and the color filter substrate 200 is opposed to the array substrate 100, and the liquid crystal is disposed between the color filter substrate 200 and the array substrate 200. The liquid crystal panel is completed by injecting the layer 300.

As described above, according to the present invention, an insulating layer having a step is formed on the color filter substrate of the liquid crystal panel corresponding to the transmission region and the reflection region, and a phase delay layer is formed on the insulation layer of the reflection region.

As a result, the phase difference of the light passing through the liquid crystal layer can be compensated even if a separate retardation film is not disposed on the back or front surface of the liquid crystal panel. In addition, it is possible to reduce the manufacturing cost and the assembly process by removing the retardation film attached to the liquid crystal panel separately. Moreover, the transmittance | permeability in the transmission mode can be improved.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (8)

In the manufacturing method of the color filter substrate for liquid crystal display devices which accommodates a liquid crystal layer through coalescence with the array substrate in which the several pixel part which has a reflection area and a transmission area was formed, (a) forming a color pixel layer on the substrate; (b) forming an insulating layer on the color pixel layer; (c) removing the insulating layer corresponding to the transmission area to form a step corresponding to the reflection area and the transmission area; (d) forming a phase delay layer over the insulating layer corresponding to the reflective region; And (e) forming a common electrode layer on the substrate having the phase delay layer formed thereon. The method of claim 1, wherein the phase delay layer is formed of a liquid crystalline polymer material. A first substrate having a plurality of pixel portions having a reflection region and a transmission region; A second substrate having a color pixel layer and having a step corresponding to the reflection area and the transmission area; A liquid crystal layer formed between the first substrate and the second substrate; And And a phase delay layer formed on the second substrate corresponding to the reflector and compensating for a phase difference of light passing through the liquid crystal layer. The display apparatus of claim 3, further comprising: a first polarizer configured to first polarize light incident on the first substrate; And And a second polarizing plate which secondly polarizes the light emitted from the second substrate. The liquid crystal display of claim 3, wherein the first cell gap of the liquid crystal layer corresponding to the reflective region and the second cell gap of the liquid crystal layer corresponding to the transmission region are different. The liquid crystal display of claim 5, wherein the first cell gap is smaller than the second cell gap. The liquid crystal display of claim 3, wherein the phase delay layer is formed of a liquid crystalline polymer material. The method of claim 3, wherein the second substrate further comprises an insulating layer formed on the color pixel layer corresponding to the reflective region, And the phase delay layer is formed on the insulating layer.

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