Need Of Flexible Circuits

In the world of electronics, necessity is the mother of all inventions, holds best applicable to the invention, evolution and development of flexible circuits in all types of electrical and electronics gadgets. The flexible circuits have just recently come of age as an interconnection technology, although it was originally developed around two decades ago.

In short, a flexible circuit is “a patterned arrangement of printed wiring utilizing flexible base material with or without flexible cover layers.”

Let us first understand the necessity of such circuits and the constraints posed by the earlier technology of printed circuit boards, which led to its invention.

Increased application of electronic devices such as car stereos, heart pacemakers, disk drives, digital cameras etc., requires greater flexibility of circuit designing and installation, to maximize space constraints. Since size of all gadgets is reducing exponentially, the need arose for designing circuits, which are functionally more capable and compact in size. Therefore came up flexible circuits to replace bulky wire attachments.

Miniaturization is the buzzword in the world of circuit designing. Great emphasis is there in reducing the size of the circuits without compromising on the performance. This required the engineer to improve the functionality and reliability of the circuits along with its flexibility. Flexible circuits are thus the solution to several spatial and orientation constraints earlier faced by fixed printed circuit boards.

How flexible circuits score over the rest?

Make –

1. A flexible circuit is made up of a flexible polymer film, which is laminated onto a thin sheet of copper that is engraved to produce a circuit pattern. The advantage of the polymer film is that the circuits can be designed and etched on both sides of the film. Another polymer overcoat is added to insulate the circuit and provide environmental protection.

2. The polymer film used for designing flexible circuits is KAPTON, which has several favourable characteristics and make it the best bet. These include heat resistance, dimensional stability, flexural capability. KAPTON’s excellent thermal stability provides a better base for surface mounting than hard boards.

3. The flat nature of such circuits offer considerable weight and space savings as compared to traditional wire harnesses. Thickness as low as 0.10mm and weight reductions of over 75% can be achieved.

Uses –

1. Flexible circuits can be used in designing several single or double-sided circuits with complex interconnections, shielding, and surface mounted devices in a multi-layer design. These multi-layer designs can also be combined with rigid circuit boards to create a rigid/flex circuit capable of supporting devices as needed.

2. Flexible circuits also give designers a third dimension to work with. As the name itself indicates, these circuits provide flexibility with which one can bend and shape around circuits along two or more planes during installation. This property can be used in complex and tight-fitting assemblies where it would be impossible to accommodate several rigid boards and harnesses.

3. Flexible circuits provide excellent means of reducing assembly time of a product due its properties of flawless integrate form and flexibility, thereby reducing number of assemble operations and testing time.

Thus, now the time for extinction of the printed circuit boards is fast approaching whereas development of flexible circuits is about to reach its pinnacle.

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