Stock material or miscellaneous articles – Structurally defined web or sheet – Continuous and nonuniform or irregular surface on layer or...
Reexamination Certificate
2002-06-20
2004-06-08
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Structurally defined web or sheet
Continuous and nonuniform or irregular surface on layer or...
C428S195100, C428S500000, C428S704000, C252S518100, C252S519140, C252S519340, C528S373000, C528S377000, C528S378000, C534S676000, C534S677000, C534S678000, C534S679000, C534S681000
Reexamination Certificate
active
06746751
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a material and a method for making a conductive pattern.
BACKGROUND OF THE INVENTION
Transparent ITO (indium-tin oxide) electrodes are used for the fabrication of flexible LC displays, electroluminescent devices and photovoltaic cells. These electrodes are made by vacuum sputtering ITO onto a substrate. This method involves high temperatures, up to 250° C., and therefore glass substrates are generally used. The range of potential applications is limited, because of the high fabrication costs, the low flexibility (pliability) and stretchability, due to the brittleness of the ITO layer and the glass substrate. Therefore interest is growing in all-organic devices, comprising plastic resins as a substrate and organic intrinsically conductive polymer layers as electrodes. Such plastic electronics allow the realization of low cost devices with new properties (Physics World, March 1999, p.25-39). Flexible plastic substrates can be provided with an intrinsically conductive polymer layer by continuous roller coating methods (compared to batch process such as sputtering) and the resulting organic electrodes enable the fabrication of electronic devices with higher flexibility and a lower weight.
The production and use of intrinsically conductive polymers such as polypyrrole, polyaniline, polyacetylene, polyparaphenylene, polythiophene, polyphenylenevinylene, polythienylenevinylene and polyphenylenesulphide are known in the art.
EP-A 440 957 discloses dispersions of polythiophenes, constructed from structural units of formula (I):
in which R
1
and R
2
independently of one another represent hydrogen or a C
1-4
-alkyl group or together form an optionally substituted C
1-4
-alkylene residue, in the presence of polyanions. Furthermore, EP-A-686 662 discloses mixtures of A) neutral polythiophenes with the repeating structural unit of formula (I),
in which R
1
and R
2
independently of one another represent hydrogen or a C
1-4
-alkyl group or together represent an optionally substituted C
1-4
-alkylene residue, preferably an optionally with alkyl group substituted methylene, an optionally with C
1-12
-alkyl or phenyl group substituted 1,2-ethylene residue or a 1,2-cyclohexene residue, and B) a di- or polyhydroxy- and/or carboxy groups or amide or lactam group containing organic compound; and conductive coatings therefrom which are tempered at elevated temperature, preferably between 100 and 250° C., during preferably 1 to 90 seconds to increase their resistance preferably to <300 ohm/square.
Coated layers of organic intrinsically conductive polymers can be structured into patterns using known microlithographic techniques. In WO-A-97 18944 a process is described wherein a positive or negative photoresist is applied on top of a coated layer of an organic intrinsically conductive polymer, and after the steps of selectively exposing the photoresist to UV light, developing the photoresist, etching the intrinsically conductive polymer layer and finally stripping the non-developed photoresist with an organic solvent, a patterned layer is obtained. A similar technique has been described in 1988 in Synthetic Metals, volume 22, pages 265-271 for the design of an all-organic thin-film transistor. Such methods are cumbersome as they involve many steps and require the use of hazardous chemicals.
WO 01/88958 published on Nov. 22, 2001 discloses a method of forming a pattern of a functional material on a substrate comprising: applying a first pattern of a first material to said substrate; and applying a second functional material to said substrate and said first material, wherein said first material, said second functional material, and said substrate interact to spontaneously form a second pattern of said second functional material on said substrate, to thereby form a pattern of a functional material a substrate.
Aspects of the Invention
It is an aspect of the present invention to provide a process for making a conductive pattern, which does not require the use of hazardous chemicals.
It is a further aspect of the present invention to provide a material having a conductive pattern without a development step.
It is a further aspect of the present invention to provide a material having a conductive element that can be processed to a conductive pattern by a simple, convenient method which involves a low number of steps and which does not require the use of hazardous chemicals.
Further aspects and advantages of the invention will become apparent from the description hereinafter.
SUMMARY OF THE INVENTION
A conductive pattern can be realized with the materials of the present invention, which are optionally conductivity enhanced, without image-wise heating or exposure and with optionally a single wet processing step, and optional conductivity enhancement. No etching liquids or organic solvents are required. Furthermore, a conductive pattern is realized in layers ≦500 nm thick without processing.
Aspects of the present invention are realized by a material having a conductive pattern, the material comprising a support and a conductive element, the conductive element being 500 nm thick or less and containing a polyanion and an intrinsically conductive polymer, characterized in that one surface of the conductive element is an outermost surface of the material and the other surface of the conductive element is contiguous with a patterned surface, the patterned surface consisting of at least two types of surface element, and those parts of the conductive element contiguous with a type A surface element exhibiting a surface resistance at least a factor of ten greater than those parts of the conductive element contiguous with a type B surface element.
Aspects of the present invention are also realized by a material for making a conductive pattern, the material comprising a support and a conductive element, the conductive element containing a polyanion and an intrinsically conductive polymer, characterized in that one surface of the conductive element is an outermost surface of the material, the other surface of the conductive element is contiguous with a patterned surface, the patterned surface consisting of at least two types of surface element, and those parts of the conductive element contiguous with one type of the surface elements are capable of being at least partially removed by a developer.
Aspects of the present invention are also realized by a method of making a conductive pattern on a support comprising the steps of: providing a material for making a conductive pattern as disclosed above; processing the material with a developer, thereby at least partially removing those parts of the conductive element contiguous with one type of the surface elements; and optionally treating the material to increase the electroconductivity of the material.
Further advantages and embodiments of the present invention will become apparent from the following description.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
The term “support” means a “self-supporting material” so as to distinguish it from a “layer” which may be coated on a support, but which is itself not self-supporting. It also includes any treatment necessary for, or layer applied to aid, adhesion to the differentiable element.
The term conductive means having a surface resistance or 10
11
&OHgr;/square or less and is a generic term including both the terms antistatic and electroconductive.
The term electroconductive means having a surface resistance below 10
6
&OHgr;/square. Antistatic materials have surface resistances in the range from 10
6
to 10
11
&OHgr;/square and cannot be used as an electrode.
The term conductive pattern means a pattern with elements which have different surface resistances.
The term intrinsically conductive polymer means organic polymers which have (poly)-conjugated &pgr;-electron systems (e.g. double bonds, aromatic or heteroaromatic rings or triple bonds) and whose conductive properties are not influenced by environmental factors such as relative humidity.
The term con
Lamotte Johan
Terrell David
Agfa-Gevaert
Jones Deborah
Leydig , Voit & Mayer, Ltd.
Xu Ling
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