Fabricating method of a liquid crystal display device comprising rubbing direction of alignment film substantially the same as the light absorption axis

• US 8,059,255 B2
• Filed: 06/23/2005
• Issued: 11/15/2011
• Est. Priority Date: 12/13/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Choi, Sang Ho, Choi, Su Seok
• Primary Examiner(s): Robinson; Mark
• Assistant Examiner(s): CHANG, CHARLES S
• Application Number:
  US11/159,232
• Publication Number:
  US 20060126000A1
• Time in Patent Office: 2,336 Days
• Field of Search: 349/172, 349/133, 349/49, 349/100
• US Class Current: 349/172
• CPC Class Codes: G02F 1/133711 by organic films, e.g. polymeric films
• CPC Class Codes: G02F 1/133726 made of a mesogenic material
• CPC Class Codes: G02F 1/133788 by light irradiation, e.g. linearly polarised light photo-polymerisation

Abstract

A liquid crystal display device includes an upper substrate including an upper polarizer having a first light absorption axis and an upper electrode, a lower substrate including a lower polarizer having a second light absorption axis substantially parallel to the first light absorption axis and a lower electrode, a ferroelectric liquid crystal layer formed on at least one of the upper substrate and the lower substrate, and a nematic system liquid crystal layer formed on the ferroelectric liquid crystal layer between the upper substrate and the lower substrate.

Claims

1. A fabricating method of a liquid crystal display device, comprising the steps of:

forming an upper polarizer having a first light absorption axis on an upper substrate;

forming a lower polarizer having a second light absorption axis on a lower substrate, the second light absorption axis being substantially parallel to the first light absorption axis;

forming an electrode on each of the upper substrate and the lower substrate;

forming an upper alignment film on the upper substrate;

forming a lower alignment film on the lower substrate;

forming a ferroelectric liquid crystal layer on at least one of the upper alignment film and the lower alignment film; and

forming a nematic system liquid crystal layer on the ferroelectric liquid crystal layer,

wherein the light absorption axes of the polarizers are substantially in parallel each other when the liquid crystal display device is viewed in a diagonal direction,

wherein a first rubbing direction of the upper alignment film and a second rubbing direction of the lower alignment film are substantially the same as the first and second light absorption axes,

wherein the liquid crystal display device drives in a normally white mode such that a transmissivity decreases as an external voltage to be applied to at least one of the electrodes increases,

wherein the step of forming the ferroelectric liquid crystal layer includes the steps of;

forming a ferroelectric liquid crystal solution by mixing a ferroelectric liquid crystal into a solvent, wherein the solution includes between about 93 wt % and 97 wt % of the ferroelectric liquid crystal and between about 3 wt % and 7 wt % of the solvent;

spreading the solution over at least one of the upper substrate and the lower substrate;

evaporating the solvent within the solution by heating the substrate; and

aligning a spontaneous polarization direction of the ferroelectric liquid crystal using any one of a step of exposing the ferroelectric liquid crystal to a medium having high or low polarity, and applying a magnetic field to the ferroelectric liquid crystal.

2. The fabricating method according to claim 1, wherein the step of forming the ferroelectric liquid crystal layer includes the steps of:

forming a ferroelectric liquid crystal solution by mixing a ferroelectric liquid crystal with a photopolymerization monomer;

spreading the solution over at least one of the upper substrate and the lower substrate;

aligning a spontaneous polarization direction of the ferroelectric liquid crystal; and

polymerizing the photopolymerization monomer by irradiating the solution with ultraviolet ray.

3. The fabricating method according to claim 2, wherein the solution includes between about 95 wt % and 99 wt % of the ferroelectric liquid crystal and between about 1 wt % and 5 wt % of the photopolymerization monomer.

4. The fabricating method according to claim 2, wherein the step of aligning the spontaneous polarization direction of the ferroelectric liquid crystal includes any one of a step of exposing the ferroelectric liquid crystal to a medium having high or low polarity, applying an electric field to the ferroelectric liquid crystal, and applying a magnetic field to the ferroelectric liquid crystal.

5. The fabricating method according to claim 1, wherein the step of forming the ferroelectric liquid crystal layer includes the step of:

forming a first ferroelectric liquid crystal layer on the upper substrate; and

forming a second ferroelectric liquid crystal layer on the lower substrate.

6. The fabricating method according to claim 5, further comprising the step of aligning a spontaneous polarization direction of the first ferroelectric liquid crystal layer opposite to a spontaneous polarization direction of the second ferroelectric liquid crystal layer.

7. The fabricating method according to claim 1, further comprising the step of aligning a spontaneous polarization direction of the ferroelectric liquid crystal layer towards the substrate on which it is formed.

8. The fabricating method according to claim 1, further comprising the step of aligning a spontaneous polarization direction of the ferroelectric liquid crystal layer towards the nematic system liquid crystal layer.