Liquid crystal display cell and method of making the same

Disclosed is a liquid crystal display cell comprising first and second panels spaced apart from each other and extending parallel to each other, first and second conductive layers respectively disposed on and between the first and second panels, first and second orientation layers covering the first and second conductive layers, respectively, and a liquid crystal layer disposed between the first and second orientation layer. Each of the first and second orientation layers comprises a polymer material and a liquid crystal material dispersed within the polymer.

FIELD OF THE INVENTION 
The present invention relates to a liquid crystal display cell ("LCD") cell 
with an inventive orientation layer and a method for manufacturing the 
same. 
BACKGROUND OF THE INVENTION 
Generally, an LCD cell is structured such that liquid crystal molecules are 
injected between two plates, and by regulating power of an electric field, 
the amount of light transmission is controlled. 
As shown in FIG. 2, the conventional LCD cell is made by depositing 
conductive layers 3 on each of two glass plates 2, forming orientation 
layers 4 on each of the conductive layers 3, dispersing spacers 5 between 
the two glass plates 2, sealing an edge portion by using a sealant 8, and 
forming a liquid crystal layer by injecting liquid crystal molecules 7. 
The above LCD cell controls an arrangement of liquid crystal molecules 7 by 
providing the conductive layer 3 with an electric field through drive 
integrated circuits. 
Further, the liquid crystal orientation layer 4 is made of a polyamide 
layer deposited on the glass plates 2 through a printing process, and an 
orientation process is conducted by rubbing a surface of the polyamide 
layer with a soft cloth. 
In the conventional LCD cell formed as described above, because the 
orientation layer is formed by performing an orientation process requiring 
rubbing, static electricity is created and the LCD cell is contaminated by 
dust and other foreign substances transferred from the cloth. 
SUMMARY OF THE INVENTION 
The present invention has been made in an effort to solve the above 
problems. 
It is an object of the present invention to provide an LCD cell that does 
not require a rubbing process and, thus, solves the above-described static 
electricity and foreign substances problems. 
To achieve the object, in the present invention. An orientation layer of 
the LCD cell is made from a liquid crystal polymer material or other 
polymer materials where liquid crystal molecules are dispersed. Here, 
without utilizing a rubbing process, orientation of the liquid crystal 
molecules of the liquid crystal layer is performed by means of the 
interaction between the liquid crystal molecules dispersed in the polymer 
material of the orientation layer and the liquid crystal molecules of the 
liquid crystal layer.

DETAILED DESCRIPTION 
A preferred embodiment of the present invention will now be described in 
detail with reference to the accompanying drawing. 
As shown in FIG. 1, an LCD cell according to a preferred embodiment of the 
present invention is made by depositing a conductive layer 12 on upper and 
lower glass plates 10; depositing an orientation Layer 14, made from 
polymer materials in which liquid crystal molecules 15 are dispersed, on 
the conductive layer 12; distributing spacers 18 between the two glass 
plates 10; sealing outside edge portions using a sealant 16 except a 
portion through which liquid crystal molecules will be injected; and 
injecting liquid crystal molecules 22 to form a liquid crystal layer 20 
between the two glass plates 10. 
The liquid crystal molecules 15 dispersed in the polymer will be referred 
to as dispersive liquid crystal molecules hereinafter to distinguish them 
from the liquid crystal molecules 22 of the liquid crystal layer 20. The 
orientation layer 14 made from the polymer materials each containing the 
dispersive liquid crystal molecules 15 will be referred to as a liquid 
crystal orientation layer. 
Other polymer material constituting the dispersive liquid crystal 
orientation layer 14 may be selected from one of the following polymer 
materials: polyimide, polyamide or liquid crystal polymer(LCP). 
In the above, it is preferable that an amount of the dispersive liquid 
crystal molecules 15 dispersed in the polymer material is about 5-30 Wt %. 
That is, a polymer solution and a liquid crystal solution are respectively 
prepared by melting a polymer material and a liquid crystal material into 
solvents. Then, the polymer solution and the liquid crystal solution are 
mixed together. This mixed solution is deposited on the glass plates and 
then evaporated in a vacuum, thereby forming the liquid crystal 
orientation layer 14. 
The solvent is preferably selected from one of r-butyrolactone, 
cyclohexanone, tetrachloroethane, N-methyl pyrrolidinone (NMP), and other 
such solvents. 
In the above LCD cell, before injecting liquid crystal molecules into the 
LCD cell, the cell is heat-treated at a temperature higher than an 
isotropic temperature of the dispersive liquid crystal orientation layer 
14 so that the dispersive liquid crystal molecules can display liquid 
crystal qualities in the cooling process of the cell. Preferably, the 
liquid crystal molecules 22 are injected into the LCD cell during the 
cooling process so that the orientation of the liquid crystal molecules 22 
of the liquid crystal layer 20 is created by means of the interaction 
between the dispersive liquid crystal molecules 15 and the liquid crystal 
molecules 22. The orientation of the dispersive liquid crystal molecules 
15 is determined by the interaction between a dielectric constant of a 
longitudinal axis direction of each of the dispersive liquid crystal 
molecules 15 and a dielectric constant of a longitudinal axis direction of 
the liquid crystal molecules 22 of the liquid crystal layer 20. That is, 
when the dispersive liquid crystal molecules 15 display liquid crystal 
qualities during the cooling process, the liquid crystal molecules 22 of 
the liquid crystal layer 20 perform orientation by means of the 
interaction by a dipole moment according to the dispersive liquid crystal 
molecules 15 and the dielectric constant of the longitudinal axis 
direction, while a pretilt angle is formed according to the extent of this 
interaction. 
To make the above-described LCD cell, various tests were performed. 
Materials used in the tests were as follows: 
1. Polymer for the liquid crystal orientation layer: polyimide sold under 
the trademarks "SE5291", and liquid crystal polymers sold under the 
trademark "LCP94", "LCP95", "LCP100" and "LCP105". 
2. Liquid crystal materials sold under the trademarks "ZLI1132", "ZLI2293", 
and "ZLI3086". 
3. Solvents: Cylohexanone, NMP, r-butyrolactone, and tetrachloroethane. 
4. Wt % of the polymer melted in the solvent: 2 Wt % 
5. Wt % of the liquid crystal material dispersed in the polymer: 5 Wt % 
Test Results 
The following were the test results of the fusible extent of the liquid 
crystal materials and the polymer material in the solvents: 
1. In NMP, SE5291 and LCP95 showed high fusibility, ZLI1132 showed normal 
fusibility, and ZLI3086 showed normal fusibility after forming a clump. 
2. In r-butyrolactone, SE5291 and LCP95 showed high fusibility, and ZLI1132 
showed normal fusibility. 
3. In cyclohexanone and tetrachlorethane, all liquid crystal and polymer 
materials showed high fusibility. 
The following were the test results of the extent of the orientation and 
the pretilt angle when the liquid crystal orientation layer 14 was formed 
with SE5291 and the dispersive liquid crystal molecules. 
1. Using NMP as a solvent and ZLI1132 as the dispersive liquid crystal 
molecules 15 in the liquid crystal orientation layer 14 formed on the 
upper and lower glass plates 10: 
(a) When ZLI1132 was used as the liquid crystal molecules 22 forming the 
liquid crystal layer 20, orientation was not performed; 
(b) When ZLI 2293 was used, orientation was normal and the pretilt angle 
was 0.37.+-.0.42.degree.; and 
(c) When ZLI3086 was used, orientation was not performed. 
2. Using NMP as a solvent and ZLI1132 as the dispersive liquid crystal 
molecules 15 in the dispersive liquid crystal orientation layer 14 formed 
on the liquid crystal orientation layer 14 formed on the upper glass plate 
10, and ZLI3086 as the dispersive liquid crystal molecules 15 in the 
dispersive liquid crystal orientation layer 14 formed on the lower glass 
plate 10: 
(a) When ZLI1132 was used as the liquid crystal molecules 22 forming the 
liquid crystal layer 20, orientation was not performed; 
(b) When ZLI2293 was used, orientation was relatively good and the pretilt 
angle was 0.78.+-.0.14.degree.; and 
(c) When ZLI3086 was used, orientation was performed as normal and the 
pretilt angle was 0.40.+-.0.21.degree.. 
3. Using NMP as a solvent and ZLI3086 as the dispersive liquid crystal 
molecules 15 in the dispersive liquid crystal orientation layer 14 formed 
on the upper and lower glass plates 10: 
(a) When ZLI3086 was used as the liquid crystal molecules 22 of the liquid 
crystal layer 20, orientation was not performed; 
(b) When ZLI2293 was used, orientation was performed as normal and the 
pretilt angle was 0.36.+-.0.14.degree.; and 
(c) When ZLI3086 was used, orientation was not performed. 
4. Using cyclohexanone as a solvent, ZLI1132 as the dispersive liquid 
crystal molecules 15 in the liquid crystal orientation layer 14 formed on 
the upper glass plate 10, and ZLI3086 as the dispersive liquid crystal 
molecules 15 in the dispersive liquid crystal orientation layer 14 formed 
on the lower glass plate 10: 
(a) When ZLI1132 was used as the liquid crystal molecules forming the 
liquid crystal layer 20, orientation was not achieved; 
(b) When ZLI2293 was used, orientation was achieved as in a normal state 
and the pretilt angle was 0.36.+-.0.24.degree.; and 
(c) When ZLI3086 was used, orientation was not performed. 
The following were the test results of the extent of orientation and the 
pretilt angle measured when: a) forming the liquid crystal orientation 
layer 14 through the use of the LCP95 and liquid crystal molecules, b) 
using cyclohexanon as a solvent, c) using ZLI 1132 as the dispersive 
liquid crystal molecules 15 in the liquid crystal orientation layer 14 
formed on the upper glass plate 10, using ZLI3086 as dispersive liquid 
crystal molecules 15 in the liquid crystal orientation layer 14 formed on 
the lower glass plate 10, and d) using ZLI2293 as the liquid crystal 
molecules 22 forming the liquid crystal layer 20. 
1. When injecting the liquid crystal molecules 22 at 82.9 and annealing 
LCP95 for two hours at 93.degree. and letting it go through a sudden 
cooling process, orientation was normal and the pretilt angle appears at 
0.degree.. 
2. When injecting the liquid crystal molecules 22 at 92.90 and annealing 
LCP95 for two hours at 9.degree. and letting it cool at room temperature 
for three hours, orientation was relatively good and the pretilt angle 
appears at 0.degree.. 
3. When injecting the liquid crystal molecules 22 at 46.7.degree. and 
annealing LCP95 for two hours at 93.degree. and letting it cool for three 
hours at room temperature, orientation was relatively good and the pretilt 
angle appears at 0.degree.. 
4. When injecting the liquid crystal molecules 22 at room temperature, and 
annealing LCP95 for two hours at 93.degree. and letting it cool for three 
hours at room temperature, orientation was normal and the pretilt angle 
appears at 0.degree.. 
When the liquid crystal orientation layer 14 was formed through the use of 
LCP95+liquid crystal molecules, there appears in a dark background a 
straight line pattern defect in the direction to which liquid crystal 
molecules are injected and in the vertical direction, but orientation 
seems to be performing. If observed again after a period of 50 hours, the 
overall orientation and the pretilt angle are maintained but transparent 
curve lines are somewhat smoothed. 
The following were the test results of the extent of orientation and the 
pretilt angle measured when forming the orientation layer with LCP94, 
LCP100 and LCP105 without dispersive liquid crystal materials and using a 
tetrachloroethane as a solvent. 
1 Using LCP94 
(a) When ZLI1132 was used as, the liquid crystal molecules 22, orientation 
was not performed; 
(b) When ZLI2293 was used, orientation was not performed normally at first 
but not after five days; and 
(c) When ZLI3086 was used, orientation was not achieved. 
2. Using LCP100: 
(a) When ZLI1132 is used as: the liquid crystal molecules 22, orientation 
was not performed; 
(b) When ZLI2293 was used, orientation was formed normally and the pretilt 
angle appears at 0.degree.; and 
(c) When ZLI3086 was used, orientation is not achieved. 
3. Using LCP105: 
(a) When ZLI1132, ZLI2293 and ZLI3086 were used as the liquid crystal 
molecules 22, orientation was not performed. 
Also, when using LCP94, LCP100 and LCP105, which do not disperse the liquid 
crystal molecules, line patterns appeared having lines in parallel, 
vertical, and liquid crystal molecules injecting directions as when 
forming the dispersive liquid crystal orientation layer 14 using 
LCP95+liquid crystal molecules. However, in the remaining areas liquid 
crystal orientation is performed by the interaction between the dispersive 
liquid crystal orientation layer 14 and the liquid crystal molecules. 
As shown in the various experiments above, the best results are achieved 
when using LCP95 as the orientation layer; forming the dispersive liquid 
crystal orientation layer, formed on the upper and lower glass plates, by 
means of using liquid crystal molecules in which there is a large 
difference in the dielectric constant in the longitudinal axis direction 
(for example, ZLI1132 having a dielectric constant of the longitudinal 
axis direction of 15 and ZLI2293 of 2.9); and using ZLI2293 as the liquid 
crystal molecules forming the liquid crystal layer. 
In the LCD cell of the present invention formed as in the above, as the 
orientation process is not performed by means of rubbing but by means of 
cooling slowly after dispersing and heating liquid crystal molecules on 
the orientation layer, the creation of static electricity and the 
possibility of contamination from a cloth, as used in the orientation 
process of the prior art, are prevented. 
While this invention has been described in connection with what is 
presently considered to be the most practical and preferred embodiment, it 
is to be understood that the invention is not limited to the disclosed 
embodiments, but on the contrary, is intended to cover various 
modifications and equivalent arrangements included within the spirit and 
scope of the appended claims.