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Need Of Flexible Circuits Within the global world of electronics, necessity is the mother of all inventions, holds best applicable to the innovation, evolution and growth of flexible circuits in every types of electric and electronics gadgets. The flexible circuits have just recently come of age as an interconnection technology, although it had been originally developed around two decades ago.

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Simply speaking, a flexible circuit is "a patterned arrangement of printed wiring utilizing flexible base material with or without flexible cover levels."

Let us first realize the need of such circuits while the constraints posed by the earlier technology of printed circuit boards, which led to its invention.

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Increased application of electronic devices such as car stereos, heart pacemakers, disk drives, electronic cameras etc., requires greater flexibility of circuit designing and installation, to maximize space constraints. Since size of most devices is reducing exponentially, the need arose for designing circuits, that are functionally more compact and capable in proportions. Therefore came up flexible circuits to replace cumbersome wire attachments.
Miniaturization is the buzzword in the global 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 increase the reliability and functionality associated with circuits along with its flexibility. Versatile circuits are thus the clear answer to several spatial and orientation constraints earlier faced by fixed printed circuit boards.
How circuits that are flexible over the others?
Make -
1. a versatile circuit that is flexible consists of a flexible polymer film, which is laminated onto a slim sheet of copper that is etched to produce a circuit pattern. The bonus of the polymer film is that the circuits are designed and etched on both sides of the movie. Another polymer overcoat is added to insulate the circuit and supply protection that is environmental.
2. The polymer film useful for designing flexible circuits is KAPTON, which has several favourable characteristics and make it the bet that is best. These include heat resistance, dimensional stability, flexural capability. KAPTON's excellent stability that is thermal a better base for surface mounting than hard boards.
3. The flat nature of such circuits offer considerable weight and area savings as when compared with wire that is traditional. Thickness as little as 0.10mm and weight reductions of over 75% may be accomplished.
Uses -
1. Flexible circuits can be used in designing a few single or double-sided circuits with complex interconnections, shielding, and area mounted devices in a multi-layer design. These multi-layer designs can also be combined with rigid circuit panels to create a circuit that is rigid/flex of supporting products as required.
2. Flexible circuits also give designers a third measurement to work with. Because the title itself suggests, these circuits offer flexibility with which one can bend and shape around circuits along two or higher planes during installation. This property is used in complex and assemblies that are tight-fitting it would be impossible to accommodate several rigid boards and harnesses.
3. versatile circuits offer excellent means of reducing installation time of something due its properties of flawless integrate form and flexibility, therefore reducing wide range of assemble operations and evaluating time.
Thus, now the right time for extinction regarding the printed circuit boards is quickly approaching whereas growth of flexible circuits is about to achieve its peak. FORMS OF FLEXIBLE CIRCUITS
Flexible circuit is a pattern of conductors created on a bendable movie, often polymers, which acts as an insulating base material. The very best is covered with an insulating address layer. a flexible circuit is in fact a counterpart to a rigid printed circuit board.
There are four basic kinds of flexible circuits, varying in levels of complexity which can be used in various combinations to solve almost every interconnection design issue.
1. Single-sided versatile circuits -
This is the simplest of most types and provides maximum freedom for dynamic applications. These circuits that are simple also the absolute most easily adaptable to SMT (surface mount technology), TAB (Tape Automated Bonding), and other developments in circuit technology. It is called single sided because the circuit allows access from one side only. Its applications have been in the field of optical pick-up for computers, camera, camcorder, VCD players, vibration motors for mobile phones etc.
These are typically the absolute most least expensive, and produced in the volume that is greatest. Single-sided circuits find maximum application in appliances where dynamism is required like in case of printers and disk drive heads.
Single layer circuit is created using a method known as back baring or dual access. This technique enables access to the metal conductors from both sides regarding the circuit. This technique eliminates requirement of plate-through holes as required in multilayer circuits.
2. Double-sided circuits that are flexible
As the name suggests, these circuits have actually two conductive layers that are frequently available from both sides. Their features that are main component assembly on both sides. Although, their ability to flex reduces because of their thickness and complexity in design but their capability to interconnect between edges using plate-through hole helps to implement complex designs without compromising on flexibility.
This type of circuits are utilized when circuit density and layout cannot be routed on a layer that is single. Additionally utilized in shielding applications and surface mount assembly that is dense.
3. Multi-layer flexible circuits -
These circuits are ideal for complex, highly dense design requirements. Many conductors are interwoven into a package that is small. Freedom may be reduced somewhat, dependent on the number of layers in the look. Multilayer circuits will be the ideal technology to conquer design challenges like unavoidable crossovers, particular resistance requirements, eradication of crosstalk in sensitive and painful circuits, additional shielding of ground planes, and component density that is high.
4. Rigid-flex circuits -
These are mixture of rigid circuits and flex circuits. So the advantages are had by it of both. Rigid-flex circuits are a hybrid construction, consisting of rigid and versatile substrates laminated together into a single package and electrically interconnected by method of plate-through holes.
Rigid-flex boards are ordinarily multilayer designs, but double-sided (two-metal layer) constructions are feasible as well, and, in fact, have actually been chosen for certain microelectronic chip-packaging applications, such as in the construction of hearing helps.