Friday, April 20, 2018
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Cut & Paste Printed Resistors and Capacitors
Standard sheet of printed resistors and capacitors produced through an advanced screen-printing process.

Polymer thick film circuits were always considered an economical solution, but performance levels from the printed circuit technology were sub-par due to poor resolution and electrical conductivity. Traditional thick film circuits were intended for typical low-end items such as keyboard membrane switches and touch panels on microwaves. Technical advances with ink materials and printing equipment over the last few years have trickled down, and the wiring capabilities of the new thick film circuits are closer to those of traditional etched copper circuits.

DKN Research, an engineering firm specializing in micro electronics and packaging technology, has developed a new passive component series of printed resistors and capacitors built with fine silver thick film circuits on flexible film substrates for cut-and-paste applications. This is possible through an advanced screen-printing process using special silver inks, carbon inks, dielectric inks and related materials that include substrates and insulating materials as the fundamental technology for printable electronics.

Advanced Screen-Printing Technology
DKN Research developed an "Advanced Screen-Printing Technology" and can build functional thick film circuits by partnering with equipment and material manufacturers. The new technology can produce fine silver traces down to 30µ lines and spaces for double and multilayer circuits with 80µ via holes. The conductivity of the new silver traces is one order higher compared to traditional thick film circuits.

Surprisingly, the conductor traces are available for soldering, unlike traditional polymer thick film circuits where soldering is impossible. In addition, the new advanced screen-printing technology makes it possible to build embedded passive components and EL-based optical components on flexible substrates. The technology is valuable in building new electronic devices such as high-density touch panel switches, functional sensor modules, large size signboards, and flexible displays. The technology is also beneficial for building additional fine conductive traces on other circuit devices including multi-layer rigid boards, flexible circuits, ceramic circuits and monolithic IC chips.

Value-Added Components
Our company continues to develop broad ranges of printable passive components that are truly value-added using advanced screen-printing technology. Currently, a wide range of resistances is available in the form of printed resistors from 100Ω to 10MΩ, as well as a large capacitances of up to 5000pF as printed capacitors with fine line silver circuits built on flexible substrates. The look and performance from these printed components differ from traditional discrete components, so we are now marketing a set of printed resistors and capacitors built on polyimide film — a kind of "beginner's kit" for designers and engineers to experiment with. The set of resistors on the sheet range from 1kΩ to 100kΩ and capacitors from 100 to 1000pF, screen-printed on 4-in.2 silver conductor flexible circuits.

Users can measure the performance of these printed components built on the film, and cut out and use the appropriate items simply by using a knife or scissors. Each resistor or capacitor can be pasted on circuit boards using glue. Conductive glue, conductive sticky tape or low temperature soldering are recommended for making the components' electrical connections to other circuit board conductors. This is a fast, easy and convenient way for circuit designers and R&D engineers to build and test prototype circuits for new electronic devices.

The company inventories a broad range of materials, and can supply appropriate materials meeting specific application needs. We can conduct prototype and mid-volume fine-line thick film circuit production as a part of the engineering service with cooperating partner companies.

New Materials and Processes
Screen-printing is not a new technology in the printed circuit industry. However, the combinations of new paste materials and an advanced screen-printing process further increases the value of printable flexible electronics that cannot be made by the traditional photolithography process with copper foils. In addition, more functionality from the circuits will be generated with new materials in the future.

Furthermore, the screen-printing process is capable of building more layers including insulation materials, in addition to the resistance materials, dielectric materials for capacitance and screen-printed inductors. The screen-printing process is capable of generating via holes between the conductive layers without drilling and copper plating — providing great opportunities to produce low-cost solutions for embedded passives with multi-layer circuits. The latest trials for fluorescent materials have even produced flexible EL panels.

Contact: DKN Research LLC, 62 Adams St., Haverhill, MA 01830-6862 978-436-1417 E-mail: Web:

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