Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1997-07-23
2001-04-17
Malinowski, Walter J. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S148000
Reexamination Certificate
active
06219125
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an electrode plate, particularly an electrode plate provided with a specific metal electrode and a transparent electrode formed thereon and a production process of the electrode plate. The present invention also relates to a liquid crystal device including the electrode plate and a production process thereof.
On light-transmissive (glass) substrates of twisted nematic (TN)-type or super twisted nematic (STN)-type liquid crystal devices, there have generally been conventionally formed ITO (indium tin oxide) films as transparent electrodes. However such ITO films constituting the transparent electrodes have a fairly high resistivity, so that they have caused a problem of a voltage waveform deformation (or distortion) due to electrical signal delay along with increases in size and resolution of a display area in recent years. Particularly, in liquid crystal devices using a ferroelectric liquid crystal, this problem has become more noticeable since such devices have included a cell structure having a smaller cell gap (e.g., 1.0-2.0 &mgr;m).
In order to solve the problem, it may be possible to increase the thickness of the transparent electrodes, but the formation of such thick transparent electrodes requires increased time and cost and results in an inferior adhesiveness to the substrates.
In order to solve the above-mentioned problems, it has been proposed an electrode plate having structure in which a plurality of metal (e.g., A1) electrodes showing a low resistivity are formed on a glass substrate and a plurality of transparent electrodes of e.g., ITO film formed on the metal electrodes so as to be electrically connected therewith.
In recent years, there has also been proposed an electrode plate using metal electrodes of Cu showing a further low resistivity in order to provide a larger opening region (wider optical modulation region) and a higher response speed to a resultant liquid crystal device.
However, in the case where such an electrode plate using Cu electrodes showing a resistivity lower than A1 electrodes is used for providing a liquid crystal device having a larger opening region and an improved responsiveness, the resultant liquid crystal device is accompanied with problems such that an adhesiveness between Cu electrodes and a glass substrate is liable to be lowered and that Cu electrodes are liable to be corroded due to oxidation thereof.
Further, when a polymeric material (e.g., ultraviolet (UV)-curable resin) is filled in spacings between Cu electrodes shaped in a prescribed pattern by using a press (e.g., roller press) to form a flattened surface, a small amount of the polymeric material remains on the surface of Cu electrodes. As a result, each Cu electrode has failed to ensure a good and stable electrical connection with an associated transparent electrode of, e.g., indium tin oxide (ITO) in some cases.
SUMMARY OF THE INVENTION
In view of the above-mentioned problems, a principal object of the present invention is to provide an electrode plate capable of improving adhesive properties (adhesiveness) between metal (first) electrodes and a substrate having thereon the metal electrodes while suppressing an oxidation of the metal electrodes and capable of providing a stable electrical conduction of the metal electrodes to transparent (second) electrodes formed thereon, and a liquid crystal device including such an electrode plate.
Another object of the present invention is to provide processes for producing an electrode plate and a liquid crystal device as described above.
According to the present invention, there is provided an electrode plate, comprising: a light-transmissive substrate, a plurality of first electrodes disposed on the light-transmissive substrate and a plurality of second electrodes disposed on the first electrodes, wherein
each first electrode comprises a layer of metal nitride and is electrically connected with an associated second electrode, and
each second electrode comprises a transparent electrode.
According to the present invention, there is also provided a process for producing an electrode plate comprising a light-transmissive substrate, a plurality of first electrodes disposed on the light-transmissive substrate and a plurality of second electrodes disposed on the first electrodes; said process comprising the steps of:
forming on a light-transmissive substrate a plurality of first electrodes each comprising a layer of metal nitride, and
forming on the first electrodes a plurality of second electrodes each comprising a transparent electrode so as to be electrically connected with an associated first electrode.
According to the present invention, there is further provided a liquid crystal device, comprising: pair of plates and a liquid crystal disposed between he electrode plates; at least one of the plates comprising a light-transmissive substrate, a plurality of first electrodes disposed on the light-transmissive substrate and a plurality of second electrodes disposed on the first electrodes, wherein
each first electrode comprises a layer of metal nitride and is electrically connected with an associated second electrode, and
each second electrode comprises a transparent electrode.
According to another aspect of the present invention, there is still further provided a process for producing a liquid crystal device, comprising the steps of:
providing a pair of electrode plates at least one of which is produced by the process as described above,
disposing the electrode plates opposite to each other while leaving a gap therebetween, and
filling the gap with a liquid crystal.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
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Ishikura Junri
Kameyama Makoto
Tokunaga Hiroyuki
Yoshikawa Toshiaki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Malinowski Walter J.
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