KR20070078163A - Color filter panel, thin film transistor array panel and liquid crystal display thereof - Google Patents

Abstract

A color filter display panel, a TFT(Thin Film Transistor) display panel and an LCD(Liquid Crystal Display) by using the same are provided to reduce the manufacturing cost and the thickness of an LCD. A substrate includes a color filter. A lambda/4 plate is formed at the outside of the substrate and has a slow shaft. A polarization plate is attached at the outside of the lambda/4 plate and has an absorption shaft. The slow shaft of the lambda/4 has 147+10 or 147-10 degrees about the reference direction. The absorption shaft of the polarization shaft has 15+10 or 15-10 degrees about the reference direction. The lambda/4 plate and the polarization plate are attached by an adhesive. The lambda/4 plate is coated at the lower surface of the polarization plate and also formed by curing an alignment layer and a liquid crystal layer at the lower surface of the polarization plate.

Description

COLOR FILTER PANEL, THIN FILM TRANSISTOR ARRAY PANEL AND LIQUID CRYSTAL DISPLAY THEREOF}

1 is a layout view of a liquid crystal display according to an exemplary embodiment of the present invention.

2 and 3 are cross-sectional views of the liquid crystal display shown in FIG. 1 taken along lines II-II 'and III-III', respectively.

4 and 5 are enlarged cross-sectional views of polarizing plates and lambda / 4 plate portions of a color filter substrate according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating an angular relationship between a polarizing plate and a λ / 4 plate in a color filter display panel according to an exemplary embodiment of the present invention.

FIG. 7 is a diagram illustrating an angular relationship between a polarizing plate and a λ / 4 plate in a thin film transistor array panel according to an exemplary embodiment of the present invention.

8 is a result of measuring a viewing angle in a conventional transflective condition.

9 is a result of measuring the viewing angle in the transflective conditions according to the present invention.

10 is a simulation result of the liquid crystal display according to the present invention.

11 and 12 are reflection and transmittance curves according to voltages according to liquid crystals.

FIG. 13 is a view illustrating color coordinates according to FIGS. 11 and 12.

<Description of Drawing>

3: liquid crystal layer 12: lower polarizer

15, 25: λ / 4 plate 22: upper polarizing plate

23, 26: adhesive 24: protective film

100: thin film transistor array panel 110: lower insulating substrate

121: gate line 124: gate electrode

131: storage electrode line 140: gate insulating film

151 and 154: semiconductors 163 and 165: ohmic contact layer

171: data line 173: source electrode

175: drain electrode 180: lower protective film

187: organic insulating film 190: pixel electrode

192: transparent electrode 194: reflective electrode

195: transmission region

200: color filter display plate 210: upper insulating substrate

220: black matrix 230: color filter

250: planarization film

The present invention relates to a transflective liquid crystal display device.

The liquid crystal display is one of the most widely used flat panel display devices. The liquid crystal display includes two display panels on which field generating electrodes such as a pixel electrode and a common electrode are formed, and a liquid crystal layer interposed therebetween. Is applied to generate an electric field in the liquid crystal layer, thereby determining the orientation of liquid crystal molecules in the liquid crystal layer and controlling the polarization of incident light to display an image.

The liquid crystal display device is a transmissive liquid crystal display device for displaying an image using an illumination unit located on the back of the liquid crystal cell according to a light source, a reflective liquid crystal display device for displaying an image using natural external light, and a transmissive liquid crystal display device and a reflection type It combines the structure of a liquid crystal display device, and operates in a transmissive mode that displays an image using a built-in light source of the display device itself in a dark place where an indoor or external light source does not exist, and reflects external light in an outdoor high-light environment. It is divided into a transflective liquid crystal display device which operates in a reflection mode for displaying an image.

On the outer surfaces of the two display panels of the liquid crystal display device, a polarizing plate for transmitting only a specific polarization component to incident light is attached. Between the display panel and the polarizer, a λ / 2 plate and a λ / 4 plate are disposed as phase retardation films, which are respectively λ / 2 and λ / for two polarization components that are parallel to and perpendicular to the optical axis of the phase retardation film. Give a phase difference of four.

As described above, the manufacturing cost increases due to the use of two phase retardation films, and the overall thickness of the liquid crystal display device also increases.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a liquid crystal display device in which manufacturing cost is reduced, the thickness of the liquid crystal display device is reduced, and the characteristics of the liquid crystal display device are also improved.

In order to solve this problem, in the present invention, only the λ / 4 plate and the polarizing plate are formed on the outside of the display panel.

Specifically, the color filter display panel according to the present invention includes a substrate including a color filter, a λ / 4 plate formed on the outside of the substrate and having a slow axis, and a polarizing plate attached to the outside of the λ / 4 plate and having an absorption axis. Wherein the slow axis of the λ / 4 plate has 147 ± 10 degrees with respect to the reference direction, and the absorption axis of the polarizer has 15 ± 10 degrees with respect to the reference direction,

The λ / 4 plate has a Δnd value of 155 ± 20 nm for light having a wavelength of 550 nm,

The substrate, the λ / 4 plate and the polarizing plate are attached by an adhesive,

The λ / 4 plate is coated on the lower surface of the polarizing plate,

The λ / 4 plate is cured by including an alignment layer and a liquid crystal layer on the lower surface of the polarizing plate,

The outer surface of the polarizing plate further comprises a protective film formed through a hard coating or anti-reflection treatment,

The thin film transistor array panel according to the present invention includes a substrate including a thin film transistor, a λ / 4 plate having a slow axis and having a slow axis, and a polarizing plate attached to the outside of the λ / 4 plate and having an absorption axis, The slow axis of the λ / 4 plate has 114 ± 10 degrees with respect to the reference direction, the absorption axis of the polarizer has 75 ± 10 degrees with respect to the reference direction,

The λ / 4 plate has a Δnd value of 135 ± 20 nm for light having a wavelength of 550 nm,

The substrate, the λ / 4 plate and the polarizing plate are attached by an adhesive,

The λ / 4 plate is coated on the lower surface of the polarizing plate,

The λ / 4 plate is cured by including an alignment layer and a liquid crystal layer on the lower surface of the polarizing plate,

The outer surface of the polarizing plate further comprises a protective film formed through a hard coating or anti-reflection treatment,

A liquid crystal display device according to the present invention includes a color filter display panel, a thin film transistor array panel, and a liquid crystal formed therebetween, wherein the color filter display panel includes a first substrate including a color filter, and the first substrate. A first polarizing plate formed on an upper side and having a slow axis, and a first polarizing plate attached to an upper side of the first λ / 4 plate and having an absorption axis, wherein the slow axis of the first λ / 4 plate is in a reference direction It has a 147 ± 10 degrees with respect to the absorption axis of the first polarizing plate has a 15 ± 10 degrees with respect to the reference direction, the thin film transistor array panel is a second substrate including a thin film transistor, the lower side of the second substrate A second polarizing plate having a slow axis and a second polarizing plate attached to a lower side of the second lambda / 4 plate and having an absorption axis. The slow axis of the second λ / 4 plate has 66 ± 10 degrees with respect to the reference direction, and the absorption axis of the second polarizer has 105 ± 10 degrees with respect to the reference direction.

The first λ / 4 plate is 155 ± 20 nm at Δnd value for light of 550 nm wavelength, and the second λ / 4 plate is 135 ± 20 nm at Δnd value for light of 550 nm wavelength,

The first substrate, the first λ / 4 plate and the first polarizing plate are attached by an adhesive, and the second substrate, the second λ / 4 plate and the second polarizing plate are also attached by an adhesive.

The first and second λ / 4 plates are coated on the first and second polarizing plates, respectively.

The first and second λ / 4 plates are cured by including an alignment layer and a liquid crystal layer in the first and second polarizing plates, respectively.

The outer surface of the first and second polarizing plate further comprises a protective film formed through a hard coating or anti-reflection treatment,

The viewing angle of the liquid crystal is ± 40 degrees in the 1 o'clock direction.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

First, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

FIG. 1 is a layout view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIGS. 2 and 3 are each cut along the lines II-II 'and III-III' of the liquid crystal display shown in FIG. It is a cross section.

The liquid crystal display according to the present exemplary embodiment is vertically or horizontally aligned with respect to the surfaces of the two display panels 100 and 200, and the color filter panel 200 facing the thin film transistor array panel 100 and the color filter panel 200 facing the same. It consists of the liquid crystal layer 3 containing the liquid crystal molecule.

First, the thin film transistor array panel 100 will be described.

A plurality of gate lines 121 and a plurality of storage electrode lines 131 are formed on an insulating substrate 110 made of transparent glass or plastic.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes a plurality of gate electrodes 124 protruding upward and end portions 129 having a large area for connection with another layer or an external driving circuit. A gate driving circuit (not shown) for generating a gate signal may be mounted on a flexible printed circuit film (not shown) attached to the substrate 110 or directly mounted on the substrate 110, It may be integrated into the substrate 110. When the gate driving circuit is integrated on the substrate 110, the gate line 121 may extend to be directly connected to the gate driving circuit.

The storage electrode line 131 receives a predetermined voltage and almost extends in parallel with the gate line 121. Each storage electrode line 131 is positioned between two adjacent gate lines 121 and is close to a lower side of the two gate lines 121. The storage electrode line 131 includes a storage electrode 137 extending up and down. However, the shape and arrangement of the storage electrode line 131 may be modified in various ways.

Side surfaces of the gate line 121 and the storage electrode line 131 are inclined with respect to the surface of the substrate 110, and the inclination angle is preferably about 30 ° to about 80 °.

A gate insulating layer 140 made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate line 121 and the storage electrode line 131.

A plurality of linear semiconductors 151 made of hydrogenated amorphous silicon (hereinafter referred to as a-Si) or polysilicon are formed on the gate insulating layer 140. The linear semiconductor 151 mainly extends in the longitudinal direction and includes a plurality of projections 154 extending toward the gate electrode 124. The linear semiconductor 151 has a wider width in the vicinity of the gate line 121 and the storage electrode line 131 and covers them widely.

A plurality of linear and island ohmic contacts 161 and 165 are formed on the semiconductor 151. The ohmic contacts 161 and 165 may be made of a material such as n + hydrogenated amorphous silicon in which n-type impurities such as phosphorus are heavily doped, or may be made of silicide. The linear ohmic contact 161 has a plurality of protrusions 163, and the protrusion 163 and the island-type ohmic contact 165 are paired and disposed on the protrusion 154 of the semiconductor 151.

Side surfaces of the semiconductor 151 and the ohmic contacts 161 and 165 are also inclined with respect to the surface of the substrate 110, and the inclination angle is about 30 ° to 80 °.

A plurality of data lines 171 and a plurality of drain electrodes 175 are formed on the ohmic contacts 161 and 165 and the gate insulating layer 140.

The data line 171 transmits a data signal and mainly extends in the vertical direction to cross the gate line 121 and the storage electrode line 131. Each data line 171 includes a plurality of source electrodes 173 extending toward the gate electrode 124 and an end portion 179 having a large area for connection with another layer or an external driving circuit. A data driving circuit (not shown) for generating a data signal is mounted on a flexible printed circuit film (not shown) attached to the substrate 110, directly mounted on the substrate 110, or mounted on the substrate 110. Can be integrated. When the data driving circuit is integrated on the substrate 110, the data line 171 may be extended to be directly connected to the data driving circuit.

The drain electrode 175 is separated from the data line 171 and faces the source electrode 173 around the gate electrode 124. Each drain electrode 175 includes one wide end and the other end having a rod shape. The wide end overlaps the sustain electrode 137, and the rod-shaped end is partially surrounded by the bent source electrode 173.

One gate electrode 124, one source electrode 173, and one drain electrode 175 together with the protrusion 154 of the semiconductor 151 form one thin film transistor (TFT). A channel of the transistor is formed in the protrusion 154 between the source electrode 173 and the drain electrode 175.

The side of the data line 171 and the drain electrode 175 may also be inclined at an inclination angle of about 30 ° to about 80 ° with respect to the surface of the substrate 110.

The ohmic contacts 161 and 165 exist only between the semiconductor 151 below and the data line 171 and the drain electrode 175 thereon, and lower the contact resistance therebetween. Although the linear semiconductor 151 is narrower than the data line 171 in most places, as described above, the width of the linear semiconductor 151 is widened at the portion where it meets the gate line 121 to smooth the profile of the surface, thereby disconnecting the data line 171. prevent. The semiconductor 151 has a portion exposed between the source electrode 173 and the drain electrode 175 and not covered by the data line 171 and the drain electrode 175.

A passivation layer 180 is formed on the data line 171, the drain electrode 175, and the exposed semiconductor 151. The passivation layer 180 includes a lower layer 180q made of an inorganic insulator such as silicon nitride or silicon oxide and an upper layer 180q made of an organic insulator. The upper passivation layer 180q may preferably have a dielectric constant of 4.0 or less, may have photosensitivity, and irregularities may be formed on a surface thereof. In addition, an opening 195 (transmission window) exposing a part of the lower passivation layer 180q is formed in the upper passivation layer 180q. However, the passivation layer 180 may have a single layer structure made of an inorganic insulator or an organic insulator.

In the passivation layer 180, a plurality of contact holes 182 and 185 exposing the end portion 179 and the drain electrode 175 of the data line 171 are formed, respectively, and the passivation layer 180 and the gate insulating layer are formed. A plurality of contact holes 181 exposing the end portion 129 of the gate line 121 are formed at 140.

A plurality of pixel electrodes 191 and a plurality of contact assistants 81 and 82 are formed on the passivation layer 180.

Each pixel electrode 191 is formed on the upper passivation layer 180q and includes a transparent electrode 192 and a reflective electrode 194 thereon. The transparent electrode 192 is made of a transparent conductive material such as ITO or IZO, and the reflective electrode 194 is made of a reflective metal such as aluminum, silver, chromium or an alloy thereof.

The reflective electrode 194 is positioned in the opening of the upper passivation layer 180q and has a transmission window 195 exposing the transparent electrode 192. The reflective electrode 194 exists only on a portion of the transparent electrode 192 to expose another portion of the transparent electrode 192, and the exposed portion of the transparent electrode 192 is positioned in the opening of the upper passivation layer 180q.

The pixel electrode 191 is physically and electrically connected to the drain electrode 175 through the contact hole 185 and receives a data voltage from the drain electrode 175. The pixel electrode 191 to which the data voltage is applied is generated between the two electrodes 191 and 270 by generating an electric field together with the common electrode 270 of the color filter panel 200 to which the common voltage is applied. The direction of the liquid crystal molecules of the liquid crystal layer 3 is determined. The polarization of light passing through the liquid crystal layer 3 varies according to the direction of the liquid crystal molecules determined as described above. The pixel electrode 191 and the common electrode 270 form a capacitor (hereinafter, referred to as a "liquid crystal capacitor") to maintain an applied voltage even after the thin film transistor is turned off.

The transflective liquid crystal display device including the thin film transistor array panel 100, the color filter display panel 200, the liquid crystal layer 3, and the like is a transmission area TA defined by the transparent electrode 192 and the reflective electrode 194, respectively. And a reflection area RA. Specifically, the portion located below the transmission window 195 becomes the transmission area TA, and the portion located below the reflection electrode 194 becomes the reflection area RA.

In the transmissive area TA, light incident on the rear surface of the liquid crystal display device, that is, the thin film transistor array panel 100, passes through the liquid crystal layer 3 and exits the front surface, that is, toward the color filter display panel 200. In the reflective area RA, the light enters the liquid crystal layer 3, enters the liquid crystal layer 3, is reflected by the reflective electrode 194, passes through the liquid crystal layer 3, and exits to the front surface. At this time, the bending of the reflective electrode 194 allows the light to be reflected and dispersed.

Since the upper passivation layer 180q is not present in the transmission area TA, the thickness or the cell gap of the liquid crystal layer 3 in the reflection area RA becomes half of the cell gap in the transmission area TA. .

The pixel electrode 191 and the drain electrode 175 extended portion 177 connected thereto overlap the storage electrode line 131 including the storage electrode 137. A capacitor formed by the pixel electrode 191 and the drain electrode 175 electrically connected to the pixel electrode 191 overlapping the storage electrode line 131 is called a storage capacitor, and the storage capacitor enhances the voltage holding capability of the liquid crystal capacitor.

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 and the external device.

Next, the color filter display panel 200 will be described.

A light blocking member 220 is formed on an insulating substrate 210 made of transparent glass, plastic, or the like. The light blocking member 220 is also referred to as a black matrix, and defines a plurality of opening regions facing the pixel electrode 190 and prevents light leakage between the pixel electrodes 190.

A plurality of color filters 230 are also formed on the substrate 210 and are arranged to almost fit into the opening area surrounded by the light blocking member 220. The color filter 230 may extend in the vertical direction along the pixel electrode 190 to form a stripe. Each color filter 230 may display one of primary colors such as three primary colors of red, green, and blue. The color filter 230 is formed to have a different thickness with respect to the transmission area TA and the reflection area RA. The transmissive area TA passes through the color filter 230 only once when the light passing through the transparent electrode 192 passes, but the reflective area RA includes a total of 2 when the light enters the color filter panel 200 and exits the reflected light. Passes through the first color filter 230. As a result, colors displayed in the transmission area TA and the reflection area RA may be different from each other. In order to prevent this, the color filter 230 of the transmission area TA may be replaced by the color filter 230 of the reflection area RA. It is thicker than that. In addition to the method of forming the thickness of the color filter 230 differently, the transmission area TA may also be formed by forming a region (light hole) in which the color filter is not formed in the color filter 230 of the reflective region RA. Colors in the reflective area RA can be matched.

The planarization layer 250 is formed on the color filter 230 and the light blocking member 220, and a common electrode 270 is formed thereon. The common electrode 270 is preferably made of a transparent conductive conductor such as ITO or IZO.

An alignment layer (not shown) for aligning the liquid crystal layer 3 is coated on the inner surfaces of the display panels 100 and 200, and the λ / 4 plate is provided on the outer surfaces of the display panels 100 and 200, respectively. 15 and 25 and polarizing plates 12 and 22 are provided.

The upper polarizing plate 22 and the lower polarizing plate 12 each have an absorption axis, and the upper λ / 4 plate 25 and the lower λ / 4 plate 15 have a slow axis, and the angular relationship between the absorption axis and the slow axis is shown in FIGS. It demonstrates in detail in FIG.

The liquid crystal display may further include a plurality of spacers (not shown) that hold the thin film transistor array panel 100 and the color filter panel 200 to form a gap therebetween.

The liquid crystal display may further include a sealant (not shown) that couples the thin film transistor array panel 100 and the color filter panel 200. The sealing material is located at the edge of the color filter display panel 200.

The cross-sections of the polarizing plates 12 and 22 and the λ / 4 plates 15 and 25 attached to the outside of the thin film transistor array panel 100 and the color filter display panel 200 of the liquid crystal display as described above will be described in detail. And FIG. 5. In FIG. 4 and FIG. 5, the color filter display panel 200 is described, and the λ / 4 plate and the polarizer are attached to the outside of the thin film transistor array panel 100 in the same order.

4 and 5 are enlarged cross-sectional views of a polarizer and a λ / 4 plate portion according to an embodiment of the present invention.

4 and 5 illustrate different embodiments according to the present invention. First, referring to FIG.

A film is attached to the outside of the color filter display panel 200 in the order of the λ / 4 plate 25 and the polarizing plate 22, and the color filter display plate 200, the λ / 4 plate 25 and the polarizing plate 22 are adhesive. Are attached to each other by (23, 26).

On the other hand, a protective film 24 is formed outside the polarizing plate 22 to protect the polarizing plate 22. In general, the polarizing plate 22 has a structure in which Tri Acetate Cellulose (TAC) is attached to both sides of PVA (Polyvinyl Alcohol). The protective film 24 is formed by hard coating or antireflection treatment on one side of the TAC.

As such, when only the λ / 4 plate 25 is formed between the polarizing plate 22 and the color filter display panel 200, the thickness is reduced as compared with the conventional one.

In FIG. 4, the adhesive 26 has a thickness of 25 μm, the λ / 4 plate 25 thereon is 40 μm, the adhesive 23 thereon is 20 μm, and the polarizer 22 thereon is 105 μm. The thickness of the film excluding the protective film 24 is about 190 μm.

However, when the λ / 2 plate is additionally formed, the λ / 2 plate and the adhesive layer attaching the λ / 2 plate should be further formed, so that the thickness of the λ / 2 plate is 45 μm and the adhesive 20 μm is added, resulting in a total thickness of 65 μm. . Applying this to the color filter panel and the thin film transistor array panel, the total 130㎛ is thicker.

Therefore, when formed in accordance with the present invention is 130㎛ thinner than the conventional liquid crystal display device, there is an advantage that the cost of λ / 2 plate is also reduced.

In addition, the embodiment formed as shown in FIG. 5 is also possible. 5 is an embodiment in which the λ / 4 plate is not formed as a separate film but formed by coating on one side of the polarizing plate 22.

The λ / 4 plate 25-1 coated on one side of the polarizing plate 22 is coated through the following process.

An alignment film (not shown) is formed on one side of the polarizing plate 22 and a liquid crystal layer (not shown) is formed thereon, and then cured to form a liquid crystal, which is cured while being aligned along the alignment direction of the alignment film (not shown). λ / 4 plate.

In addition, the protective film 24 is formed on the surface of the polarizing plate 22 where the λ / 4 plate 25-1 is not coated by hard coating or antireflection treatment.

On the other hand, the adhesive 26 is an adhesive for attaching to the color filter display panel 200.

The thickness of the embodiment formed as shown in FIG. 5 is as follows.

The polarizing plate 22 has a thickness of 105 μm, the coated λ / 4 plate 25-1 below is 5 μm, and the adhesive 26 below has a thickness of 25 μm, so that a total of 135 μm is excluded except for the protective film 24. 4, the thickness of 55 μm is reduced than that of the embodiment of FIG. 4, and the total thickness of the total liquid crystal display is 110 μm less than that of the embodiment of FIG. 4, and the total thickness of 240 μm is smaller than that of the conventional liquid crystal display. Has the advantage of being reduced.

4 and 5 are preferably formed in an angular relationship as shown in FIGS. 6 and 7. This is because the conventional liquid crystal display improves color compensation and display characteristics by using not only the λ / 4 plate but also the λ / 2 plate, but the λ / 2 plate is removed in the present invention. 6 is a case of a color filter display panel, and FIG. 7 is a case of a thin film transistor array panel.

First, the color filter display panel is as follows.

FIG. 6 is a diagram illustrating an angular relationship between a polarizing plate and a λ / 4 plate in a color filter display panel according to an exemplary embodiment of the present invention.

Θp is the direction of the absorption axis of the polarizing plate 22, and θr is the direction of the slow axis of the λ / 4 plate 25.

The absorption axis of the polarizing plate 22 indicates a direction that absorbs light in the corresponding direction and does not pass through, and the slow axis of the λ / 4 plate 25 is a direction that causes the light in the corresponding direction to proceed slowly, thereby changing the phase.

FIG. 6 shows the angle when the color filter display panel 200 is formed on the lower side and viewed from above with the λ / 4 plate 25 and the polarizing plate 22 formed thereon. 6 is an angle measured based on the X-axis 3 o'clock direction.

As shown in FIG. 6, the absorption axis of the polarizing plate 22 is formed at 15 degrees, and the slow axis of the λ / 4 plate 25 is formed at 147 degrees. Here, the value of the phase difference Δnd of the λ / 4 plate 25 is 155 based on the wavelength of 550 nm light. However, the above-described values may have a range of values as below when considering the error. The absorption axis of the polarizing plate 22 is formed at 15 ± 10 degrees, and the slow axis of the λ / 4 plate 25 is formed at 147 ± 10 degrees, where the phase difference Δnd of the λ / 4 plate 25 is a wavelength of 550 nm light. It is 155 ± 20nm on the basis of.

This angle is an experimental result for the liquid crystal having a cell gap of 4.1 µm and a liquid crystal Δn value of 0.067 with respect to the viewing angle of 1 o'clock. Considering the error in the liquid crystal, the applicable viewing angle of the liquid crystal is ± 40 degrees at 1 o'clock, the twist angle of the liquid crystal is 0 to 20 degrees, and the twist angle of the liquid crystal is determined by the alignment angle of the alignment layer of the upper and lower display panels. It is decided.

Meanwhile, the thin film transistor array panel will be described below.

FIG. 7 is a diagram illustrating an angular relationship between a polarizing plate and a λ / 4 plate in a thin film transistor array panel according to an exemplary embodiment of the present invention.

FIG. 7 illustrates a state where the thin film transistor array panel 100 is formed on the upper side, and the λ / 4 plate 15 and the polarizer 12 are formed thereunder and viewed from the bottom to the top. In addition, the angle in FIG. 7 is an angle measured based on the X-axis 3 o'clock direction in FIG. 7.

As shown in FIG. 7, the absorption axis of the polarizing plate 12 is formed at 75 degrees, and the slow axis of the λ / 4 plate 15 is formed at 114 degrees. Here, the value of the phase difference Δnd of the λ / 4 plate 25 is 135 based on the wavelength of 550 nm light. However, the above-described values may have a range of values as below when considering the error. The absorption axis of the polarizing plate 22 is formed at 75 ± 10 degrees, and the slow axis of the λ / 4 plate 25 is formed at 114 ± 10 degrees, where the phase difference Δnd of the λ / 4 plate 25 is a wavelength of 550 nm light. It is 135 ± 20nm on the basis of.

This angle is the result for the liquid crystal having a cell gap of 4.1 mu m and a Δn value of the liquid crystal of 0.067 with respect to the viewing angle of 1 o'clock. Considering the error in the liquid crystal, the twist angle of the applicable liquid crystal is 0 to 20 degrees, and the viewing angle is ± 40 degrees at 1 o'clock.

The angle shown in FIG. 7 is different from the angle shown in FIG. 6 and the reference angle after the liquid crystal display is formed. 6 and 7 are measured based on the direction in which the display panels 100 and 200 are viewed by the polarizers 12 and 22, and the angles thereof must be changed. When the angle in FIG. 7 is modified to the angle viewed from the side of the color filter display panel after forming the liquid crystal display device and coincides with the angle in FIG. 6, the angle of FIG. 7 described above is changed as follows.

That is, as shown in FIG. 7, the absorption axis of the polarizing plate 12 is formed at 105 degrees, and the slow axis of the λ / 4 plate 15 is formed at 66 degrees. However, the above-described values may have a range of values as below when considering the error. The absorption axis of the polarizing plate 22 is formed at 105 ± 10 degrees, and the slow axis of the λ / 4 plate 25 is formed at 66 ± 10 degrees. This angle coincides with the reference direction shown in FIG. 6 when the liquid crystal display is formed.

When the above angular relationship is used, the characteristics of the liquid crystal display device are improved as in the case of additionally mounting a conventional λ / 2 plate. Hereinafter, the characteristics of the liquid crystal display device according to the present invention will be described.

8 is a result of measuring the viewing angle in the conventional transflective conditions, Figure 9 is a result of measuring the viewing angle in the transflective conditions according to the present invention.

FIG. 8 is a λ / 2 plate and a λ / 4 plate, and FIG. 9 is a λ / 4 plate. The viewing angle is measured by the liquid crystal display device formed in the angular relationship of FIGS. 6 and 7. The figure shown on the left is the viewing angle in transmission mode, and the figure shown on the right is the viewing angle in reflection mode. As compared with FIG. 8 and FIG. 9, it can be seen that the liquid crystal display device according to the present invention using only the λ / 4 plate also shows the viewing angle of the conventional liquid crystal display device.

Looking at Figure 9 in more detail as shown in FIG.

10 is a simulation result of the liquid crystal display according to the present invention. It shows luminance curve, color coordinate, and viewing angle according to voltage from the left side, and shows the reflection mode and the transmission mode separately. Even using the λ / 4 plate as shown in Figure 10 it can be seen that it shows a sufficient V-T curve, color coordinates and viewing angle.

11 and 12 are luminance curves according to voltages measured while changing cell gaps of liquid crystals, and FIG. 11 illustrates a transmission mode and FIG. 12 illustrates a reflection mode. FIG. 13 is a diagram illustrating color coordinates at this time.

11 and 12, as the cell gap of the liquid crystal changes, its transmission / reflection characteristics change. At this time, the reflection mode is more sensitive to the cell gap than the transmission mode, and considering the reflection mode, it is most preferable that the cell gap is 3.7 mu m.

As described above, in the transflective liquid crystal display, only the λ / 4 plate is formed between the polarizing plate and the display plate, and the λ / 2 plate and the λ / 4 plate are formed by setting the directions of the absorption axis of the polarizing plate and the slow axis of the λ / 4 plate. It is possible to provide a liquid crystal display device having excellent or the same characteristics as the conventional transflective liquid crystal display device used together and having a thin thickness and a reduced production cost thereof.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, in the transflective liquid crystal display, only the λ / 4 plate is formed between the polarizing plate and the display plate, and the absorption axis of the polarizing plate and the slow axis of the λ / 4 plate are set to set the λ / 2 plate and the λ / 4 plate. It is possible to provide a liquid crystal display device having a thinner thickness and a lower production cost while having the same or better characteristics than the conventional transflective liquid crystal display device used together.

Claims (19)

A substrate comprising a color filter, Λ / 4 plate formed on the outside of the substrate and having a slow axis, A polarizer attached to the outside of the λ / 4 plate and having an absorption axis, The slow axis of the λ / 4 plate has a 147 ± 10 degrees with respect to the reference direction, the absorption axis of the polarizing plate has a 15 ± 10 degrees with respect to the reference direction. In claim 1, The λ / 4 plate is 155 ± 20 nm in Δnd value for light having a wavelength of 550 nm. In claim 1, And said substrate, said λ / 4 plate and said polarizing plate are attached by an adhesive. In claim 1, And the λ / 4 plate is coated on the lower surface of the polarizing plate. In claim 4, The λ / 4 plate is cured by including an alignment layer and a liquid crystal layer on the lower surface of the polarizing plate. In claim 1, The outer surface of the polarizing plate further comprises a protective film formed by hard coating or anti-reflection treatment. A substrate comprising a thin film transistor, Λ / 4 plate formed on the outside of the substrate and having a slow axis, A polarizer attached to the outside of the λ / 4 plate and having an absorption axis, The slow axis of the λ / 4 plate has 114 ± 10 degrees with respect to the reference direction, and the absorption axis of the polarizer has 75 ± 10 degrees with respect to the reference direction. In claim 7, The λ / 4 plate is 135 ± 20 nm in Δnd value for light having a wavelength of 550 nm. In claim 7, The substrate, the λ / 4 plate and the polarizing plate are attached by an adhesive. In claim 1, The λ / 4 plate is coated on the lower surface of the polarizing plate. In claim 10, The λ / 4 plate is cured by including an alignment layer and a liquid crystal layer on the lower surface of the polarizing plate. In claim 7, The outer surface of the polarizing plate further comprises a protective film formed by hard coating or anti-reflection treatment. In a liquid crystal display device comprising a color filter display panel, a thin film transistor array panel and a liquid crystal formed therebetween, The color filter display plate A first substrate comprising a color filter, A first lambda / 4 plate formed on the first substrate and having a slow axis; A first polarizer attached to an upper side of the first λ / 4 plate and having an absorption axis, The slow axis of the first λ / 4 plate has 147 ± 10 degrees with respect to the reference direction, the absorption axis of the first polarizer has 15 ± 10 degrees with respect to the reference direction, The thin film transistor array panel A second substrate including a thin film transistor, A second λ / 4 plate formed under the second substrate and having a slow axis; A second polarizer attached to a lower side of the second λ / 4 plate and having an absorption axis, The slow axis of the second λ / 4 plate has 66 ± 10 degrees with respect to the reference direction, and the absorption axis of the second polarizing plate has 105 ± 10 degrees with respect to the reference direction. In claim 13, The first λ / 4 plate is 155 ± 20 nm at Δnd value for light of 550 nm wavelength, and the second λ / 4 plate is 135 ± 20 nm at Δnd value for light of 550 nm wavelength. In claim 13, The first substrate, the first λ / 4 plate, and the first polarizing plate are attached by an adhesive, and the second substrate, the second λ / 4 plate and the second polarizing plate are also attached by an adhesive. Display device. In claim 13, The first and second λ / 4 plates are coated on the first and second polarizing plates, respectively. The method of claim 16, The first and second λ / 4 plates are cured by including an alignment layer and a liquid crystal layer in the first and second polarizing plates, respectively. In claim 13, A liquid crystal display device further comprising a protective film formed on the outer surface of the first and second polarizing plates through hard coating or anti-reflection treatment. In claim 13, The viewing angle of the liquid crystal is ± 40 degrees in the 1 o'clock direction.

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