Retardation film having a homeotropic alignment liquid crystal film and method for preparing the same

Abstract

The present invention relates to a retardation film having a homeotropic alignment liquid crystal film, a polarizing film, an IPS (In-Plane Switching) mode liquid crystal display and a method for preparing the same. More particularly, the present invention relates to a homeotropic alignment liquid crystal film prepared from a liquid crystal mixed solution containing a poly-merizable reactive liquid crystal monomer so as to improve a viewing angle characteristic of an ISP mode liquid crystal display and reduce a color shift; a retardation film prepared by integrating an oriented retardation film and a method for preparing the same; a polarizing film having the retardation film located between a polarizing element or plate and a liquid crystal cell and a method for preparing the same; and an IPS mode liquid crystal display having the polarizing film. There is an advantage in that since a homeotropic alignment liquid crystal film with a retardation of a thickness direction is prepared using a liquid crystal mixed solution containing a reactive liquid crystal monomer, a retardation film according to the present invention is not required for high-temperature heat treatment and cooling processes so that it can be applied to a high-speed continuous process. Further, there is an advantage in that a retardation film having an oriented retardation film integrated with the homeotropic alignment liquid crystal film is arranged between a polarizing element or polarizing plate of an IPS mod liquid crystal display and a liquid crystal cell so that a contrast ratio can be increased up to about 1520%, and a color shift characteristic can be also improved.

Description

technical field [0001] The invention relates to a retardation film, a polarizing film, an IPS (In-Plane Switching) mode liquid crystal display with a vertical alignment liquid crystal film and a preparation method thereof. More specifically, the present invention relates to a homeotropically aligned liquid crystal film prepared from a liquid crystal mixed solution containing a polymerizable reactive liquid crystal monomer to improve viewing angle characteristics and reduce color shift of an ISP mode liquid crystal display; prepared by integrating an alignment retardation film A retardation film and a preparation method thereof; a polarizing film having a retardation film positioned between a polarizing element or a polarizing plate and a liquid crystal cell and a preparation method thereof; and an IPS mode liquid crystal display having a polarizing film. Background technique [0002] In general, a narrow viewing angle is one of the most important disadvantages of liquid crys...

AI Technical Summary

Problems solved by technology

[0011] However, the retardation films obtained by the methods disclosed in Japanese Patent Laid-Open Nos. 2001-166133 and 2000-227520 have limitations in their thickness-direction extension, and there is a problem that retardation in the thickness direction cannot be widely controlled.

In addition, since the method of shrinking the retardation film by adding the shrinkage force of the heat-shrinkable film to the film has a problem that the thickness of the retardation film becomes thicker in the range of about 50 to 100 μm, so that the need for thickness reduction cannot be sufficiently satisfied.

[0012] In addition, the method of forming a homeotropic liquid crystal film using a branched liquid crystal polymer disclosed in Japanese Patent Laid-Open No. 2003-149441 has the following problem: Since the heat treatment temperature for making the homeotropic liquid crystal film have a liquid crystal phase, that is, the glass transition temperature (Tg ) is generally in the range of 60-300°C, more particularly in the range of 70-200°C, so a high-temperature heat treatment process is required; since the time consumed in the heat treatment is also in the range of 20 seconds to 30 minutes, it is difficult to use this method. in a high-speed continuous process; since a cooling operation such as air cooling, water cooling, etc. is required to fix the alignment of a vertically aligned liquid crystal film after completion of heat treatment, it is difficult to apply this method to a continuous process; and a liquid crystal polymer compound containing a liquid crystal polymer has Low solubility in compatible solvents

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