KR20050114862A - Single gap transflective liquid crystal display - Google Patents

Abstract

 The present invention relates to a semi-transmissive liquid crystal display device having a single gap. In a liquid crystal display device using a fringe electric field, the cell gaps of the reflective and transmissive areas are the same using the built-in phaser, and the image quality is excellent in both areas and the viewing angle characteristics are excellent. A semi-transmissive liquid crystal display device can be manufactured.

Description

Single Gap Transflective Liquid Crystal Display

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transflective liquid crystal displays (hereinafter referred to as LCDs), and more particularly to transflective LCDs having a single cell gap in the transmissive and reflective regions using built-in phaser. The transmissive LCD has excellent image quality, but because it uses an internal light source, power consumption is high and outdoor visibility is very low. Therefore, a reflective LCD has been proposed to improve this disadvantage. Reflective LCD uses external light source, so it consumes less power and has excellent outdoor visibility. However, as the intensity of the ambient light becomes weaker, the display quality deteriorates. Therefore, a transflective LCD has been proposed as a necessity of a device that can be appropriately selected and used according to the surrounding environment. FIG. 1 is a cross-sectional view of a transflective LCD which has been proposed in the related art. 1 (a) is a cross-sectional view of the semi-transmissive LCD using the step of the lower substrate, Figure 1 (b) is a cross-sectional view of the semi-transmissive LCD using the step of the color filter of the upper substrate. As shown in FIG. 1A, the upper substrate has an upper glass substrate 2 under the upper polarizing plate 1, and a color filter 3 under the upper glass substrate 2. The lower substrate has a lower glass substrate 7 on the lower polarizer 8, a thin film transistor 9 on the lower glass substrate 7, an insulator 10 on the thin film transistor 9, The transparent electrode 6 and the reflective electrode 5 are placed on the insulator 10. As shown in FIG. 1B, the upper glass substrate 2 is placed under the upper polarizing plate 1, and the color filter 3 is placed under the upper glass substrate 2. The lower substrate has a lower glass substrate 7 on the lower polarizer 8, a thin film transistor 9 on the lower glass substrate 7, and an insulator 10 on the thin film transistor 9. The transparent electrode 6 and the reflective electrode 5 are placed on the insulator 10. Therefore, the conventional transflective LCD has to form a step in order to form a double cell gap between the reflection area and the transmission area. The formation of such steps requires complex manufacturing processes and increases manufacturing costs.

On the contrary, the purpose of the present invention is to produce a semi-transmissive LCD using a fringe electric field, in which the reflection region and the transmission region are single gaps and the image quality is excellent in both regions.

In order to achieve the above object, the present invention uses the patterned built-in phaser to set the optimal optical cell structure of the reflective region while maintaining the same cell gap in the reflective and transmissive regions, and then the optimal optical cell structure of the transmissive region. Suggested.

Example 1

Example 1 is a single-gap semi-transmissive LCD using a fringe electric field containing a built-in retarder patterned under the liquid crystal cell. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 shows a normally black (NB) mode single gap half showing an initial dark state according to the first embodiment of the present invention. A cross-sectional view of a transmissive LCD.

As shown, the upper substrate has an upper glass substrate 2 below the upper polarizer 1. The lower substrate has a lower glass substrate 9 positioned on the lower polarizer 10. On the lower glass substrate 9, a planar electrode is coated with a reflective electrode 8 in a reflective region and a transmissive electrode 7 in a transmissive region. On top of the planar electrodes 7 and 8 is coated a patterned built-in retarder 6 which delays the phase of the light component in the reflective region and does not delay the phase in the transmissive region. An insulator 4 is placed on the upper part of the built-in phaser 6, and a slit-like transparent slit having a pixel electrode width of about 0.1 μm to 6 μm and a gap between pixel electrodes of about 1 μm to 6 μm above the insulator 4. The electrode 5 is placed. The liquid crystal 3 is positioned on the transparent electrode 5.

3 illustrates the optical cell structure of FIG. 2. Angle means the angle in the counterclockwise direction with respect to the X axis. Fig. 3 (a) shows the optical cell structure of the reflection area and Fig. 3 (b) shows the optical cell structure of the transmission area. As shown in Fig. 3 (a), the upper polarizing plate 1 is 12 ° with respect to the X axis, the rubbing direction of the liquid crystal is 12 °, and the unpatterned built-in phaser 6 is twisted 57 °, respectively. The electrode 8 is located below it. The rubbing direction of the liquid crystal is 1 ° to 45 ° for liquid crystals with negative dielectric anisotropy and 45 ° to 90 ° for liquid crystals with positive dielectric anisotropy. As shown in FIG. 3 (b), the upper polarizing plate 1 is 12 degrees with respect to the X axis, the rubbing direction of the liquid crystal is 12 degrees, and the lower polarizing plate 10 is 102 degrees, respectively.

4 illustrates reflectance and transmittance according to voltage application when the incident wavelength of the transflective LCD of FIG. 2 is 550 nm. The light efficiency is high in both the reflective and transmissive regions. The driving voltages of the reflective and transmissive regions are 2.5V and 5.0V, respectively.

FIG. 5 shows viewing angle characteristics of a reflection area and a transmission area of the transflective LCD of FIG. 2. FIG. 5 (a) shows the viewing angle characteristic of the reflective region when the incident wavelength is 550 nm. The region having the contrast ratio (hereinafter referred to as CR) of 5 or more is 80 ° up and down, left and right, but 100 It is 50 degrees in diagonal direction. 5 (b) shows the viewing angle characteristics of the transmission region, and the CR is almost 10 or more in almost all regions.

FIG. 6 is a cross-sectional view of a single-gap semi-transmissive LCD using a semi-transmissive film, in which the lower electrode is a transparent electrode in the transmissive region, and the entire flat electrode is a transparent electrode instead of the flat electrode in the reflective region, Is showing. The upper substrate has an upper glass substrate 2 below the upper polarizer 1. The lower substrate has a transflective film 8 positioned on the lower polarizing plate 9, and a lower glass substrate 7 positioned over the transflective film 8. The transparent flat electrode 6 is coated on the lower glass substrate 7. A patterned built-in phaser 5 is placed on the transparent flat electrode 6, an insulator 4 is placed on the built-in phaser 5, and a pixel electrode width of 0.1 μm to 6 μm is placed on the insulator 4. The slit-shaped transparent electrode 8 of 1 micrometer-about 6 micrometers is arrange | positioned at the interval between pixel electrodes. The liquid crystal 3 is positioned on the transparent electrode.

FIG. 7 illustrates a cross-sectional view of a single gap transflective LCD using a transflective film on a lower substrate and a transparent flat electrode and a pixel electrode disposed on the lower substrate in Example 1; The upper substrate has an upper glass substrate 2 below the upper polarizer 1, and a transparent flat electrode 3 is coated below the upper glass substrate 2. An insulator 4 is disposed below the transparent flat electrode 3, and a pixel electrode width of about 0.1 μm to 6 μm is disposed below the insulator 4, and a gap between pixel electrodes is about 1 μm to 6 μm. The electrode 5 is placed. The lower substrate has a transflective film 9 positioned on the lower polarizer 10, and the lower glass substrate 8 positioned over the transflective film 9. A patterned embedded phaser 7 is placed on the lower glass substrate 8, and a liquid crystal 6 is positioned on the embedded phaser 7.

Example 2

Unlike the first embodiment, the second embodiment of the present invention uses a non-patterned resonator that is not patterned in the liquid crystal cell and uses a retarder that is not patterned and has a λ / 4 characteristic under the lower glass substrate. It is a single-gap semi-transmissive LCD using a fringe electric field containing a quarter wave plate (QWP). Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 8 is a cross-sectional view of an NB mode single gap transflective LCD using a fringe electric field including an unpatterned embedded phaser according to a second embodiment of the present invention. As shown, the upper substrate is located on the upper polarizing plate 1 and the upper glass substrate 2. In the lower substrate, the QWP 10 is positioned on the lower polarizer 11, and the lower glass substrate 9 is positioned on the QWP 10. The planar electrode is coated on the lower glass substrate 9 by the reflective electrode 8 in the reflective region and the transmissive electrode 7 in the transmissive region. An unpatterned built-in phaser 6 is coated on the flat electrodes 7 and 8. An insulator 4 is placed on the upper part of the built-in phaser 6, and a slit-like transparent slit having a pixel electrode width of about 0.1 μm to 6 μm and a gap between pixel electrodes of about 1 μm to 6 μm above the insulator 4. The electrode 5 is placed. The liquid crystal 3 is positioned on the transparent electrode.

9 illustrates the optical cell structure of FIG. 8. Angle means the angle in the counterclockwise direction with respect to the X axis. Fig. 9 (a) shows the optical cell structure of the reflection area and Fig. 9 (b) shows the optical cell structure of the transmission area. As shown in Fig. 9A, the upper polarizer 1 is 12 ° with respect to the X axis, the rubbing direction of the liquid crystal is 12 °, and the built-in retarder 6 is 57 °, respectively, and the reflective electrode 8 is twisted. It is located below it. As shown in Fig. 9 (b), the upper polarizer 1 is 12 degrees with respect to the X axis, the rubbing direction of the liquid crystal is 12 degrees, the QWP is 147 degrees, and the lower lower polarizer 10 is 102 degrees, respectively. .

FIG. 10 shows reflectance and transmittance according to voltage application when the incident wavelength of the transflective LCD of FIG. 8 is 550 nm. The driving voltages of the reflective and transmissive regions are 2.5V and 5.0V, respectively.

FIG. 11 illustrates viewing angle characteristics of a reflection area and a transmission area of the transflective LCD of FIG. 8. Fig. 11 (a) shows the viewing angle characteristic of the reflection region when the incident wavelength is 550 nm. The region where CR is 5 or more is 160 ° in the vertical direction, left and right, but 50 ° in the 100 ° diagonal direction. FIG. 11 (b) shows the viewing angle characteristic of the transmissive region, in which the region where CR is 10 or more is 60 degrees in the 45 degree diagonal direction, but the CR is 10 or more in almost all areas.

FIG. 12 is a cross-sectional view of a single gap transflective type using a semi-transmissive film in which the lower pixel electrode is composed of a transparent electrode in a transmissive region and an entire planar electrode instead of a flat electrode, which is a reflective electrode, in a reflective region. Giving. The upper substrate has an upper glass substrate 2 below the upper polarizer 1. In the lower substrate, the lower QWP 10 is positioned on the lower polarizer 11, and the transflective film 9 is positioned on the lower QWP 10. The lower glass substrate 8 is positioned above the semi-transmissive film 9, and the transparent flat electrode 7 is placed above the lower glass substrate 8. An unpatterned phaser 6 is coated on the transparent flat electrode 7, an insulator 4 is placed on the built-in phaser 6, and a pixel electrode width of 0.1 μm is placed on the insulator 4. The slit-shaped transparent electrode 5 of about -6 micrometers and the space | interval between pixel electrodes is 1 micrometer-about 6 micrometers. The liquid crystal 3 is positioned above the transparent electrode 5. FIG. 13 shows a single-gap semi-transmissive LCD in which a transparent flat electrode and a pixel electrode positioned at the bottom thereof are positioned on an upper substrate and a semi-transmissive film is used on the lower substrate. The cross section of the The upper substrate has an upper glass substrate 2 below the upper polarizer 1, and a transparent flat electrode 3 is coated below the upper glass substrate 2. An insulator 4 is disposed below the transparent flat electrode 3, and a pixel electrode width of about 0.1 μm to 6 μm is disposed below the insulator 4, and a gap between pixel electrodes is about 1 μm to 6 μm. The electrode 5 is placed. The lower substrate has a lower QWP 10 positioned on the lower polarizer 11, a transflective film 9 positioned on the lower QWP 10, and a lower glass substrate 8 positioned on the transflective film 9. do. An unpatterned phaser 7 is placed on the lower glass substrate 8, and a liquid crystal 6 is positioned on the embedded phaser 7.

Therefore, the semi-transmissive LCD according to the present invention has the effect of eliminating manufacturing complexity and manufacturing a transflective LCD device using a fringe electric field by using a single gap. Single-gap transflective LCDs will make a significant contribution to yield and image quality improvement over conventional dual-gap transflective LCDs.

Figure 1a is a semi-transmissive LCD using a step of the lower substrate.

Figure 1b is a semi-transmissive LCD using the step of the upper color filter.

Fig. 2 is a sectional view of the transflective LCD in NB mode according to the first embodiment.

3A is an optical cell structure diagram in the reflective region of FIG.

3B is an optical cell structure diagram in the transmission region of FIG.

4 is a reflectance and transmittance curve according to the application of the voltage of FIG.

FIG. 5A is an equal contrast curve in the reflective region of FIG. 2. FIG.

5B is an equal contrast curve in the transmission region of FIG. 2.

6 is a cross-sectional view of a transflective LCD using the transflective film of Example 1. FIG.

7 is a cross-sectional view of a transflective LCD with electrodes placed on top of Example 1;

Fig. 8 is a sectional view of the transflective LCD in NB mode according to the second embodiment.

9A is an optical cell structure diagram in the reflective region of FIG.

9B is an optical cell structure diagram in the transmissive region of FIG.

10 is a reflectance and transmittance curve according to the application of the voltage of FIG.

FIG. 11A is an equal contrast curve in the reflective region of FIG. 7; FIG.

FIG. 11B is an equal contrast curve in the transmission region of FIG. 7. FIG.

12 is a cross-sectional view of a transflective LCD using the transflective film of Example 2. FIG.

Fig. 13 is a sectional view of a transflective LCD with electrodes placed on top of Example 2;

Claims (3)

An upper polarizer; An upper substrate positioned below the upper polarizer; The cell gap of the transmission region and the reflection region is the same below the upper substrate, and the lower liquid crystal layer In the reflection area, the phase of the light component is delayed and in the transmission area, the phase is delayed. A patterned built-in phaser that does not connect; The pixel electrode width under the embedded phaser is about 0.1 to 6 μm, and between pixel electrodes. A pixel electrode which is a slit-shaped transparent electrode having an interval of about 1 to 6 μm; An insulating layer under the pixel electrode; Below the insulating layer is a reflective electrode in the reflective region and a transmissive electrode in the transmissive region. A common electrode having a planar shape composed of; A driving circuit under the lower substrate; A lower substrate positioned below the common electrode; A single gap fringe electric field comprising a lower polarizer plate positioned below the drive circuit. NB mode transflective LCD using; Instead of a planar electrode consisting of a reflective electrode in the reflective area and a transmissive electrode in the transmissive area Single-gap fringe electricity using planar electrodes and transflective films, all of which are transmissive electrodes NB-mode transflective LCD with cabinet. An upper polarizer; An upper substrate positioned below the upper polarizer; The cell gap of the transmission region and the reflection region is the same below the upper substrate, and the lower liquid crystal layer A built-in phaser that is not patterned in; The pixel electrode width under the embedded phaser is about 0.1 to 6 μm, and between pixel electrodes. A pixel electrode which is a slit-shaped transparent electrode having an interval of about 1 to 6 μm; An insulating layer under the pixel electrode; Below the insulating layer is a reflective electrode in the reflective region and a transmissive electrode in the transmissive region. A common electrode having a planar shape composed of; A driving circuit under the lower substrate; A lower substrate positioned below the common electrode; A lower phase film QWP is positioned below the lower substrate; A single gap fringe electric field including a lower polarizer under the lower phase film QWP. NB mode transflective LCD using; Instead of a planar electrode consisting of a reflective electrode in the reflective area and a transmissive electrode in the transmissive area Single-gap fringe electricity using planar electrodes and transflective films, all of which are transmissive electrodes NB-mode transflective LCD with cabinet. An upper polarizer; An upper substrate positioned below the upper polarizer; Common in planar form, consisting of a transmissive electrode located below the upper substrate An electrode; An insulating layer under the common electrode; The width of the pixel electrode under the insulating layer is about 0.1 to 6 μm, and the interval between the pixel electrodes is A pixel electrode which is a transparent electrode having a slit shape of about 1 to 6 μm; The liquid crystal layer has the same cell gap between the transmission region and the reflection region below the upper pixel electrode. A built-in phaser patterned in the lower portion; A lower substrate positioned below the embedded retarder; A transflective film positioned below the lower substrate; A single gap fringe electric field including a lower polarizer plate is formed below the transflective film. NB mode transflective LCD; Unpatterned built-in phaser and semi-transmissive instead of patterned built-in phaser Using a single-gap fringe electric field with a lower phase film (QWP) NB mode transflective LCD.