Terms related to FPC flexible electronic circuit boards

- Dec 31, 2019-

Terms related to FPC flexible electronic circuit boards

FPC is a flexible electronic circuit board. A flexible circuit board is a kind of highly reliable and excellent flexible printed circuit board made of polyimide or polyester film as the substrate. Abbreviated as soft board or FPC, it has the characteristics of high wiring density, light weight and thin thickness.


PCFPC is mainly used in many products such as mobile phones, laptops, PDAs, digital cameras, LCM, etc. The following introduces the common terms related to FPC.


1, Access Hole (through hole, bottom hole)

Often refers to the coverlay of the flexible board's exterior (a through-hole that must be punched out first), which is used to fit the surface of the flexible board circuit as a solder mask. However, it is necessary to deliberately expose the hole ring hole wall or square welding pads required for welding to facilitate the welding of parts. The so-called "Access Hole" originally means that the surface layer has a through-hole, so that the outside world can "close" to the solder joints on the surface of the board under the surface protection layer. Some multilayer boards also have such exposed holes.


2, Acrylic acrylic

Rhenium is a common name for polyacrylic resin. Most of its flexible boards use its film as the adhesive film.


3, Adhesive glue or adhesive

Substances that can make the two interfaces adhere, such as resin or paint.


4. Anchoring Spurs

On the middle plate or single plate, in order to make the hole ring welding pads have stronger adhesion on the surface of the plate, a few fingers can be attached to the extra open space outside the hole ring to make the hole ring more Consolidate to reduce the possibility of floating from the surface. As shown in the figure, it is a schematic diagram of the force claws that can be seen under the "surface protective layer" of the soft board.



Is a characteristic of the dynamic flex board (for example, the print heads of computer disk drives), the quality of which should reach one billion times of "flexibility test".


6. Bonding Layer

Often refers to the film layer of multi-layer board, or TAB tape, or the board of flexible board, the adhesive layer between its copper skin and polyurethane (PI) substrate.


7. Coverlay / Cover Coat

The outer layer of the soft board is not easy to be welded with the green paint used for the hard board, because it may fall off when it is bent. Need to use a soft "acrylic" laminated on the surface of the board, which can be used as a solder mask and can protect the outer layer of the circuit, and enhance the resistance and durability of the flexible board, this special " The "outer membrane" is specifically referred to as a surface protective layer or a protective layer.


8.Dynamic Flex (FPC)

Refers to a flexible circuit board that needs to be used for continuous motion, such as the flexible board in the read-write head of a disk drive. In addition, there is "Static FPC", which refers to soft boards that have no action after being assembled properly.


9. Film Adhesive adhesive film, adhesive film

Refers to a dry sheeting adhesive layer, which can include a sheet of reinforcing fiber cloth, or a thin layer of only adhesive material without reinforcing material, such as the adhesive layer of FPC.


10, Flexible Printed Circuit, FPC soft board

Rhenium is a special circuit board that can make three-dimensional space changes during downstream assembly. Its substrate is flexible polyimide (PI) or polyester (PE). This soft board is also like a hard board, and can be made with plated through holes or surface adhesive pads for through hole insertion or surface adhesion. The surface of the board can also be covered with a soft cover layer for protection and soldering purposes, or a soft solder-proof green paint can be printed on it.


11.Flexural Failure

 Break or damage caused by repeated bending and bending actions is called Flexural Failure.


12, Kapton polyimide soft material

This is the trade name of DuPont's products. It is a kind of "polyimide" sheet-like insulating soft material, which can be made into a flexible board (FPC) substrate after being attached with rolled copper foil or electroplated copper foil .


13. Membrane Switch

The transparent polyester film is used as the carrier, and the silver paste (SilverPastes or silver paste) is printed on the thick film circuit by screen printing method. It is then combined with a hollowed out gasket and combined with a protruding panel or PCB. And become a "touch" switch or keyboard. This small "button" device is often used in handheld calculators, electronic dictionaries, and remote controls for some home appliances.


14.Polyester Films

Referred to as PET sheet, the most common is MylarFilms, a product of DuPont, which is a material with good electrical resistance. In the circuit board industry, the transparent protective layer on the surface of the imaging dry film and the coverlay on the surface of the flexible board (FPC) are PET films, and they can also be used as the substrate of the silver paste printed film circuit (MembraneCircuit). In the electronics industry, it can also be used as the insulation layer of cables, transformers, coils, or tubular containers of multiple ICs.


15.Polyimide (PI)

Gadolinium is an excellent resin polymerized by Bismaleimide and Aromaticdiamine. It was first known as the powdered resin product Kerimid 601 introduced by the French company "Rhone-Poulenc". DuPont made it into a sheet called Kapton. This PI sheet has excellent heat resistance and electrical resistance. It is an important raw material for flexible board (FPC) and automatic tape and tape (TAB). It is also an important sheet for high-grade military hard boards and super computer motherboards. This material The Chinese translation is "Polypyramine".


16. Reel to Reel reel (disc) linkage operation

Some electronic parts and components can be produced by a roll (reel) retractable process, such as TAB, IC's metal frame (Lead Frame), some flexible boards (FPC), etc. Convenient, complete its online automatic operation to save time and labor costs for one-piece operation.

Previous:3D flexible circuits will help lighten medical equipment Next:Application circuit for improving power supply reliability