Flexible electronics
Encyclopedia
Flexible electronics, also known as flex circuits, is a technology
for assembling electronic circuit
s by mounting electronic devices on flexible
plastic
substrates, such as polyimide
, PEEK
or transparent conductive polyester
film. Additionally, flex circuits can be screen printed silver circuits on polyester
. Flexible electronic assemblies may be manufactured using identical components used for rigid printed circuit board
s, allowing the board to conform to a desired shape, or to flex during its use. These flexible printed circuits (FPC) are made with a photolithographic technology. An alternative way of making flexible foil circuits and/or flexible flat cables (FFCs) is laminating very thin (0.07 mm) copper strips in between two layers of PET. These PET layers, typically 0.05 mm thick, are coated with an adhesive which is thermosetting, and will be activated during the lamination process. FPCs and FFCs have several advantages in many applications:
s, a common application of flex circuits is in computer keyboard manufacturing; most keyboards made today use flex circuits for the switch matrix.
In LCD
fabrication, glass is used as a substrate. If thin flexible plastic or metal foil is used as the substrate instead, the entire system can be flexible, as the film deposited on top of the substrate is usually very thin, on the order of a few micrometres.
Organic light-emitting diode
s (OLEDs) are normally used instead of a back-light for flexible displays, making a flexible organic light-emitting diode
display.
s have been developed for powering satellite
s. These cells are lightweight, can be rolled up for launch, and are easily deployable, making them a good match for the application.
On the other hand, Copper indium gallium diselenide (CIGS) solar cells are lightweight, flexible, and durable, which make them ideal for portable power (including solar jackets). CIGS is 1.5 to 2x greater in performance than comparable thin-film flexible solar materials.
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
for assembling electronic circuit
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
s by mounting electronic devices on flexible
Flexible
Flexible may refer to:* Flexible electrical cable, also known as a power cord* Flexible electronics* Flexible response* Flexible mold* Flextime* Flexible-fuel vehicle* Flexible rake receiver* Flexible spending account, a tax-advantaged savings account...
plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
substrates, such as polyimide
Polyimide
Polyimide is a polymer of imide monomers. The structure of imide is as shown. Polyimides have been in mass production since 1955...
, PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
or transparent conductive polyester
LED Headliner
The Dictionary of Automotive Terms defines headliners "as fabric or vinyl upholstery on the interior of the roof of a vehicle". Wikipedia's definition is a bit more informative: "A headliner is a composite material that consists of a face fabric with nonwoven or foam backing that is adhered to the...
film. Additionally, flex circuits can be screen printed silver circuits on polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
. Flexible electronic assemblies may be manufactured using identical components used for rigid printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
s, allowing the board to conform to a desired shape, or to flex during its use. These flexible printed circuits (FPC) are made with a photolithographic technology. An alternative way of making flexible foil circuits and/or flexible flat cables (FFCs) is laminating very thin (0.07 mm) copper strips in between two layers of PET. These PET layers, typically 0.05 mm thick, are coated with an adhesive which is thermosetting, and will be activated during the lamination process. FPCs and FFCs have several advantages in many applications:
- Tightly assembled electronic packages, where electrical connections are required in 3 axes, such as cameras (static application).
- Electrical connections where the assembly is required to flex during its normal use, such as folding cell phones (dynamic application).
- Electrical connections between sub-assemblies to replace wire harnesses, which are heavier and bulkier, such as in cars, rocketRocketA rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...
s and satellites. - Electrical connections where board thickness or space constraints are driving factors.
Applications
Flex circuits are often used as connectors in various applications where flexibility, space savings, or production constraints limit the serviceability of rigid circuit boards or hand wiring. In addition to cameraCamera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
s, a common application of flex circuits is in computer keyboard manufacturing; most keyboards made today use flex circuits for the switch matrix.
In LCD
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
fabrication, glass is used as a substrate. If thin flexible plastic or metal foil is used as the substrate instead, the entire system can be flexible, as the film deposited on top of the substrate is usually very thin, on the order of a few micrometres.
Organic light-emitting diode
Organic light-emitting diode
An OLED is a light-emitting diode in which the emissive electroluminescent layer is a film of organic compounds which emit light in response to an electric current. This layer of organic semiconductor material is situated between two electrodes...
s (OLEDs) are normally used instead of a back-light for flexible displays, making a flexible organic light-emitting diode
Flexible organic light-emitting diode
A flexible organic light emitting diode is a type of organic light-emitting diode incorporating a flexible plastic substrate on which the electroluminescent organic semiconductor is deposited. This enables the device to be bent or rolled while still operating...
display.
Photovoltaic cells
Flexible solar cellSolar cell
A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....
s have been developed for powering satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s. These cells are lightweight, can be rolled up for launch, and are easily deployable, making them a good match for the application.
On the other hand, Copper indium gallium diselenide (CIGS) solar cells are lightweight, flexible, and durable, which make them ideal for portable power (including solar jackets). CIGS is 1.5 to 2x greater in performance than comparable thin-film flexible solar materials.
See also
- Amorphous siliconAmorphous siliconAmorphous silicon is the non-crystalline allotropic form of silicon. It can be deposited in thin films at low temperatures onto a variety of substrates, offering some unique capabilities for a variety of electronics.-Description:...
- Copper indium gallium selenideCopper indium gallium selenideCopper indium gallium selenide is a I-III-VI2 semiconductor material composed of copper, indium, gallium, and selenium. The material is a solid solution of copper indium selenide and copper gallium selenide...
(CIGS) - Flexible circuitFlexible circuitThe industry standard IPC-T-50 "Terms and Definitions for Printed Boards" defines a flexible circuit as:"A patterned arrangement of printed wiring utilizing flexible base material with or without flexible cover layers."...
- Flexible keyboard
- KaptonKaptonKapton is a polyimide film developed by DuPont which can remain stable in a wide range of temperatures, from -273 to +400 °C...
- Polyimide Film
- Rollable electronics
- Printed electronicsPrinted electronicsPrinted electronics is a set of printing methods used to create electrical devices on various substrates. Printing typically uses common printing equipment or other low-cost equipment suitable for defining patterns on material, such as screen printing, flexography, gravure, offset lithography and...
- Roll-to-roll
- Solar vehicleSolar vehicleA solar vehicle is an electric vehicle powered completely or significantly by direct solar energy. Usually, photovoltaic cells contained in solar panels convert the sun's energy directly into electric energy. The term "solar vehicle" usually implies that solar energy is used to power all or part...
- Stretchable electronicsStretchable electronicsStretchable electronics, also known as elastic electronics or elastic circuits, is a technology for building electronic circuits by depositing stretchable electronic devices and circuits onto stretchable substrates or embed them completely in a stretchable material such as silicones or polyurethanes...
- Thin filmThin filmA thin film is a layer of material ranging from fractions of a nanometer to several micrometers in thickness. Electronic semiconductor devices and optical coatings are the main applications benefiting from thin film construction....