Optical display panel structure

A liquid crystal display cell includes two opposing substrates at least one of which is made of a highly polymerized transparent compound film. The transparent film is extended from the liquid crystal display cell. Wiring patterns are formed on the thus extended portion of the transparent film. Semiconductor circuit elements for driving the liquid crystal display cell are mounted on the extended portion of the transparent film and electrically connected to the wiring patterns.

BACKGROUND OF THE INVENTION 
The present invention relates generally to an optical device and, more 
particularly, to a structure for an optical display panel such as a liquid 
crystal display panel. 
Recently, an optical display panel such as a liquid crystal display panel, 
has been proposed with an improved terminal connection structure. See, for 
example, copending U.S. patent application, Ser. No. 188,562, filed on 
Sept. 18, 1980 by F. Funada et al. entitled "ELECTRODE TERMINAL ASSEMBLY 
ON A MULTI-LAYER TYPE LIQUID CRYSTAL PANEL". 
A United Kingdom counterpart was filed, also on Sept. 18, 1980, as patent 
application No. 8030273 and a West German counterpart was filed on the 
same day as Patent Application No. P 30 35 268.2. The disclosure of each 
of these patent applications is incorporated herein by reference. 
A purpose of recent development efforts as shown by each of these patent 
applications is to provide an electrode lead scheme that is easy to 
manufacture and handle, the scheme including a very large number of 
terminals for connecting an optical cell such as a liquid crystal display 
device, to a power source. 
However, the prior art electrode lead structures inclusive of each of the 
above-identified patent applications could not provide excellence with 
respect to, for example, the small mass or thinness of the optical cell. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an 
improved optical display panel such as a liquid crystal display. 
It is another object of the present invention to provide such an improved 
optical display panel with a very large number of terminals, the panel 
being very compact and very thin. 
Other objects, advantages, features and further scope of applicability of 
the present invention will become apparent from the detailed description 
given hereinafter. It should be understood, however, that the detailed 
description and specific examples, while indicating preferred embodiments 
of the invention, are given by way of illustration only, since various 
changes and modifications within the spirit and scope of the invention 
will become apparent to those skilled in the art from the following 
detailed description. 
To achieve the above objects, pursuant to a preferred embodiment of the 
present invention, at least one substrate of a liquid crystal display 
panel is made of a transparent highly polymerized compound film. The 
transparent highly polymerized compound film is extended from the panel 
section to support the semiconductor circuit elements. Electrodes for the 
liquid crystal display panel are formed on the transparent highly 
polymerized compound film in the panel section and electrically connected 
to the semiconductor circuit elements via wiring patterns formed directly 
on the transparent highly polymerized compound film.

DETAILED DESCRIPTION OF THE INVENTION 
Now with specific reference to FIG. 1, an optical display panel embodying 
the present invention includes a film 21 composed of a highly polymerized 
compound such as a polyethyleneterephthalate film, for example, "DIAFOIL" 
manufactured by Mitsubishi Plastic Industries Ltd., a polycarbonate film 
manufactured by, for example, Toray Industries Company, a 
polyvinyllidenefluoride film manufactured by, for example, Asahi Glass 
Co., Ltd., and a tetrafluoroethylene hexafluoropropylene copolymer film 
manufactured by, for example, Asahi Glass Co., Ltd. Each of these 
compounds is transparent, flexible with an appropriate degree of rigidity, 
and thermally stable. The film 21 supports an optical display panel such 
as a matrix type liquid crystal display panel, and a driver circuit 
therefor. 
FIG. 2 shows a step of a manufacturing process employed to complete the 
display assembly as shown in FIG. 1, wherein a semiconductor circuit 
element is coupled or adhered to a conductive coating by thermal bonding. 
Returning to FIG. 1 with greater particularity, the film 21 composed of a 
highly polymerized transparent compound is provided as a substrate for a 
control circuit unit 13 and for a liquid crystal display panel 1. The film 
21 supports a plurality of transparent electrodes 6 functioning as the 
column electrodes of the liquid crystal display panel 1 manufactured by a 
process whereby conductive and patterned electrodes made of, e.g., 
In.sub.2 O.sub.3 are formed. The conventional orientation procedures such 
as rubbing or slant evaporation are applied thereon after an insulating 
film, such as SiO.sub.2, is formed. 
A wiring pattern 22 is provided for connecting the transparent electrodes 6 
to a driver circuit comprising one or more active or passive elements such 
as an IC. A suitable conductive coating composition is deposited on the 
film 21 by screen printing or the like. The thus deposited coating film is 
dried to form the pattern 22. Preferred examples of the conductive coating 
composition are made by mixtures of the following substances: 
1. Metallic or non-metallic conductive materials: Powdered Ag, Au, or C 
2. Fixer: 
Chloroprene-rubber; 
Chlorosulfonate-rubber; 
Polyurethane; or 
Vinyl acetate ethylene copolymer 
3. Binder: 
Dimethylformamide; 
Dimethylacetamide; 
Diethyl carbitol; 
Butyl carbitol; 
Carbitol; 
Turpentine oil; 
Pine oil; 
Ethylene glycol; 
Glycerol; 
Butyl acetate; 
Cellosolve; or 
Cellosolve acetate 
Usually, the powdered carbon particles are used. To provide a low 
resistivity for the electrode, a first layer can be printed containing 
powdered silver particles and a second layer can be printed thereover 
containing the powdered carbon particles. 
A conventional transparent counter substrate 26, formed from conventional 
transparent material carries patterned electrodes 6', as row electrodes, 
which have insulating films thereon through the application of liquid 
crystal orientation techniques. On the other surface of the substrate 26, 
a polarizer 2' and a reflection plate 8 are disposed. Then, the substrate 
26, as a counter substrate, is positioned opposite to the film 21 with an 
appropriate distance therebetween to provide a cavity closed laterally by 
a sealing element 4. The element 4 is disposed around the periphery of the 
cavity to define the liquid crystal display cell. 
Another polarizer 2 is disposed on the film 21 at the other side from the 
substrate 26. Liquid crystal material 7 is injected within the cavity 
between the film 21 and the substrate 26. Thus, a liquid crystal display 
panel 1 of the matrix electrode type is formed comprising the film 21, the 
substrate 26, the transparent electrodes 6 and 6', the polarizers 2 and 
2', the sealing element 4, the reflection plate 8, and the liquid crystal 
mixture 7. 
To provide an accurate separation between the film 21 and the substrate 26, 
powdered glass fiber particles may be dispersed within the display area of 
the cavity; however they must be removed before the liquid crystal mixture 
7 is injected by vacuum injection. If it is possible that the liquid 
crystal molecular orientation treated layer may be removed or damaged 
mechanically while printing the wiring pattern 22, it may be necessary to 
coat the orientation treated layer with a film of "SILITECT", manufactured 
by Controlyne Inc., or to dispose an appropriate film on the display area 
of the display 1. These protective films should be removed after printing 
the wiring pattern 22. 
Instead of the above manufacturing process, another process may be applied, 
e.g., one comprising steps of making the liquid crystal display panel 
assembly 1 by patterning the electrodes, evaporating the insulating 
layers, and treating the liquid crystal molecule orientation process, and 
the final step of printing the wiring pattern. 
An IC 15 inclusive of passive and active circuit elements forming a driver 
circuit is connected to the wiring pattern 22 formed on the film 21 by the 
following steps, with reference to FIG. 2. A cushioned material 23 such as 
a rubber plate is disposed on a supporting table 25. The film 21 is 
disposed on the cushioned material 23. On the film 21, the wiring pattern 
22 is disposed on which the IC 15 is arranged appropriately. A thermal 
head 24 having a cushioned material 23' such as a rubber at its tip, 
presses, with an appropriate temperature such as about 150.degree. to 
180.degree. Centigrade, leads coupled to the IC 15 against the wiring 
pattern 22. Electrical connection between the leads and the wiring pattern 
22 is facilitated with the help of resin within the wiring pattern, which 
is readily adhered to the pattern 22. Thus, the driver circuit 13 is 
completed. 
This arrangement is featured in that the film 21 functions as a transparent 
substrate for the column electrodes 6 of the liquid crystal display panel 
1 and that, because of the flexibility of the film 21, the display panel 1 
and the driver circuit unit 13 may be opposed to each other by a U-shaped 
folding of the film 21. The total mass of this display assembly is made 
thin and compact. The wiring pattern 22 is thus composed of conductive 
coating film. 
FIG. 3 shows another preferred example of a liquid crystal display panel in 
plan view. In this example, a circuit substrate 27 such as a ceramic plate 
or the like is adhered to the film 21. One or more IC's 15 are disposed on 
the film 21 for providing column signals to the matrix type liquid crystal 
display 1. Connection terminals 28 between the circuit substrate 27 and 
wirings disposed on the film 21, the wirings being coupled to the IC's 15 
as previously described, are provided which are bonded together by the 
above-mentioned thermal bonding with pressure. An insulating coating can 
be printed on the film 21. In case where another circuit substrate is 
connected to the circuit elements on the film 21 as, shown in FIG. 3, to 
print the insulating coating in addition to the above stated conductive 
coating makes their connection stronger and easier than to print only the 
conductive coating because of the cooperation by the conductive and the 
insulating coatings. As shown in FIG. 3, counter substrate 26 
corresponding to the like-numbered element in FIG. 1 extends from the 
portion of film 21 which forms the first substrate of display 1. In 
forming the finished device, portion 26 is positioned opposite display 
area 1 of film 21, as shown in FIG. 1. 
In this example, the conductive coating preferably includes a thermoplastic 
resin such as chloroprene-rubber and phenol resin, aluminum powder, and a 
binder made of toluene ethyl acetate. 
A multi-layer wiring technique can be applied to the highly polymerized 
transparent film 21 to minimize the wiring pattern size within the purview 
of the invention. 
In the foregoing embodiments, the highly polymerized compound film 21 is 
used for the front substrate of the liquid crystal display panel. 
Accordingly, there is a possibility that an interference color pattern is 
observed due to the cooperation of the sandwiching polarizers and the 
film. Of course, the interference is not observed in the dynamic 
scattering mode liquid crystal display, wherein the polarizers are not 
employed, 
FIG. 4 shows a preferred arrangement to minimize the occurrence of 
interference color patterns. When the film substrate 21 is rounded between 
the polarizers 2 and 2', there are four directions 31 at which little 
interference is observed. If the direction 31 is parallel with the 
polarizing direction of the polarizers, the interference color pattern is 
never observed. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications are 
intended to be included within the scope of the invention as defined by 
the following claims.