Stretchable interconnects for flexible electronic surfaces

A conductive paste and method of fabricating thereof. The conductive paste comprises conductive particles dispersed in an organic medium, the natural medium comprising: (a) a solvent; and (b) a binder comprising a polyester. The conductive paste typically comprises silver and may contain several other additives. A stretchable conductive coating can be formed by curing the conductive paste.

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BACKGROUND

 
Capacitive touchscreen displays, such as those existing in smart telephones, rely on the electrical properties of your body to discover when and where on a screen the user is not touching. Because of this, capacitive displays can be controlledwith very mild touches of a finger and generally can’t be used with a mechanical stylus or even a gloved hand. For a capacitive device, the capacitive display is made from an insulating layer that can also be translucent, such as plastic or glass. If theinsulating layer is transparent, then a thin trace of transparent conductive material is utilized to form electrical patterns on the inside of the insulating material layer. When a user touches the monitor with his finger, then some of this fee is transferred to theuser, so the fee on the capacitive layer decreases. This reduction is measured in circuits located at each corner of the screen. The computer calculates, from the comparative differences accountable at each corner, where the touch event tookplace then relays that data to the touch-screen driver program.
 

 
Flexible electronic equipment, also known as flexible circuits, result from assembling electronic circuits by mounting electronics on flexible substrates. The flexibility of the circuit is usually limited not only by the flexibility of thesubstrate, but also by the flexibility of the electronic devices, circuit lines and interconnections mounted on the substrate.
 

 
Conductive layers, circuit wiring and interconnections may be formed using a conductive paste, usually comprising conductive particles dispersed in an organic medium. Present conductive pastes are not suitable for selective structuring atthe micron-sized degree, as required, as an instance, in microelectronics manufacture. In addition, these pastes do not exhibit adequate resistance to environmental effects such as, for instance, extremes of temperature. Conventional conductive pastes maycomprise an epoxy resin. In these pastes, the hardening agent is hard and flaky, a therefore the pastes are not suitable for manufacturing flexible circuits. The electrically conductive pastes are also likely to form a gel after being kept in storage fora long time. Other conventional polymeric pastes have the disadvantage of non-flexibility. As a result, a functional circuit made of conventional electrically conductive paste is likely to crack. Conventional conductive pastes, such as, as an instance,those containing silver nanoparticles or metal complex particles can’t generally be sintered at reduced temperature. Accordingly, as soon as a circuit or conductive layer or interconnection is formed on a substrate using such conventional pastes, damage to thesubstrate may happen.
 

 
There is a demand to get a conductive paste effective at forming a flexible conductive layer, circuit cable and/or interconnection at reduced temperature, which is capable of being stretched with no considerable crack formation or substantial loss inelectrical continuity. There is also a necessity to produce solderable flexible paste for applications such as, by way of example, decorative LED lighting.
 

 
The present invention seeks to undertake at least some of the issues related to the prior art or at least to supply a commercially suitable alternative solution thereto.
 

 
The current invention provides a conductive paste containing conductive particles dispersed in an organic medium, the organic medium containing: a solvent; along with a binder containing a polyester.
 

 
Each aspect or embodiment as described herein may be used with any other aspect(s) or embodiment(s) unless clearly indicated to the contrary. Specifically, any features indicated as being beneficial or preferred may be used with anyother characteristic indicated as being beneficial or preferred.
 

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