FOIL OVERLAYS
DECORATION AND PROTECTION
Keyboards with mechanical keys indicate several defectiveness in demanding environments especially when liquid and dust are present. An additional protection of the mechanical keys can be realized wih a graphic foil which is equipped with assembling adhesive. A product with this funtion is called a foil overlay. It is actually a decorative part of a membrane keyboard with all of its properties and funtions with the exception that in this case the electric function is done by mechanical keys of an appropriate quality placed on a PCB(Printed Circuit Board)
. The keys which are suitable for this realization are also called »short travel« keys.

GRAPHIC PART
Colour layers are printed from the bottom side of the graphic foil so that wearing out of information is not possible. An appropriate quality of a graphic foil enables the necessary maintenance and cleaning of devices and the use in most demanding environments.

ASSEMBLING ADHESIVE
The bottom side of a printed graphic foil is equipped with assembling adhesive the purpose of which is to fix the foil to the carrier. Thickness of the glue can be adjusted to the keyboyard construction in a way that the optimal contact between mechanical keys and the foil is achieved which enables a suitable key responsiveness. The adhesive is removed from the keys' positions and transparent windows' positions. The represented keyboard composition assures high IP standards as well.

FOIL OVERLAY CAN BE EMBOSSED
The ergonomy and usefullness of a mechanical keyboard equipped with a foil overlay can be additionaly perfected by selective embossing of a graphic foil in the area of keys. The graphic foil forming improves attractiveness and the appearance of the entire application at one time. The shape of the embossed surface is arbitrary.

FLAT TYPE
EMBOSSED TYPE
(frame or full embossing)
EMBOSSED TYPE
(poly-dome embossing)

EMBOSSING AS AN OPTION
The ergonomy and practicability of the keyboard can be additionaly perfected by selective embossing of keyboard's graphic foil's active surfaces – keys. By so doing the keys become more attainable and the switching feeling better. It also enhances the attractiveness and appearance of the entire application. The shape of the embossed areas is arbitrary.

TRANSPARENT SURFACES
The foil overlay as a product retains all the possibilities considering the integration of transparent surfaces of different quality. Selective adjustment of graphic foil's certain surfaces makes possible for the use of LCD and LED displayes. A perfect clearness and transparency of the keyboard can be achieved if needed as well as only semi - transparency in various colour shades.

CHANGEABLE INFORMATION
An insertion of information stripe pockets is an option. The pocket can be formed between a graphic foil and the carrier or within a foil overlay with an additional foil level.

MATERIALS FOR MAKING A GRAPHIC FOIL
When making a graphic foil or a membrane keyboard polycarbonate and polyester foils can be used as a basic substratum for the realization of the graphic part. An appropriate superficial foil treatment enables the resistance of a graphic foil against the superficial wearing out and it's chemical resistance. The upper surface of a graphic foil is clear or semi-transparent.

GRAPHIC MATERIAL CHARACTERISTICS
polycarbonate polyester
AVAILABLE THICKNESSES 0.175, 0.375 mm 0.15, 0.2, 0.28 mm
SURFACE FINISHES matte clear, matte, velvet
OPTICAL CLARITY excelent very good
PRINTABILITY excelent acceptable
CUTTING AND EMBOSSING excelent acceptable
LASER CUTTING acceptable excelent
CHEMICAL RESISTANCE acceptable excelent
OUTDOOR EXPOSURE STABILITY acceptable acceptable
ABRASION RESISTANCE acceptable excelent
LIFE TIME 50.000 - 200.000 cycles * 1,0 - 5,0 milion cycles **
THERMAL STABILITY excelent acceptable
THERMAL EXPANSION acceptable excelent
  * 50.000 cycles in embossed application, 200.000 cycles in flat applications
** 1,0 milion cycles in embossed application with metal domes,
    5,0 milion cycles in flat, non-tactile application


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