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Types of carrying laminates | Print |

PCB based keyboard has several variants. To produce them, we use several types of copper laminates, depending on the future keyboard properties.

1. Laminate FR4 (epoxy-glass type)

It's typical laminate used for the production of printed circuits. In the very standard version(known to all PCB designers) it's 1,5-1,6mm thin and is covered with copper foil with a thickness of 0,018-0,035mm.

In the production of self-adhesive keyboards, materials with a 0,1-0,2mm thickness are used. The entire keyboard, along with the layers between and graphic foil can have 0,9-1,4mm, which allows to apply it, inter alia, to many standard casings - where facet depression is on the point of 1,0-1,5mm.

pin connectors and support at FR4 board
pin connectors and support at FR4 board
It's possible to use thick laminate 2,0 - 3,0mm, which allows to create stiff front panel. To this panel another plates with electronic elements will be mounted (LCD displays, back-lighted keys,sockets, power switches etc.)

Laminates FR4 basic advantage is the possibility to solder electronic elements and cable bunches. It allows easy montage and service.

2. Polyester-based laminate

ZIF/NonZIF joint made from poliester laminate
ZIF/NonZIF joint made from poliester laminate
Circuits implemented on the FR4 basis have a fundamental defect - they are not flexible. Even thin 0,1mm laminate is to fragile,to create elements that are bending durable. Solution here is 0,01mm laminate with 0,0017mm copper layer used by our company. That connection allows to produce elastic lead-outs that are similar to typical foil keyboards(used with ZIF joint/NonZIF and Crimpflex type) - unfortunately this material is not very temperature resistant when we solder. So it makes, electronic elements montage harder.

3. Polyimide-based lamiantes (Kapton)

flexible PCB made from polyimide
flexible PCB made from polyimide
The application of polyimide foil as a carrier for the copper layers eliminates the polyester weaknesses. It becomes possible to solder for example : LED, besides that material has high multiple bending resistance. Unfortunately cost of that material are relatively high, that's why it's used mainly for creating small elements - flexible bonds in a solutions, where key role has miniaturization and mentioned above bending resistance.

 
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