In production of flexible keyboards we keep up the following constructional restrictions:

  • Distance between the two adjacent conducting layers must be not less than 0.5 mm;
  • Contact zone (the part of a button that must be pressed for device mode change) dimensions are 9x9 mm or 10x10 mm. The key’s shape and dimension does not matter but the pushing must be done in the central part of key or in the specially designated place. The restricted dimensions of the contact zone allow excluding a film deformation in the place of multiple pressings during the long term of keyboard’s service. The distance between the contact zones (keys) must be not less than 1.5 mm.
  • Minimal distance between edge of the front panel and key (not in the cable output area) is 1.5 mm.
  • Minimal distance between first row of keys and edge of the front panel in the cable output area is 10 mm.
  • Connecting cable with contacts as a rule has length 100-200 mm, 4-32 contacts, and 1 mm of minimal distance between conductive tracks; width of the conductor in connector area is determined by allowable signal power loss — the wider conductive track gives the lower resistance.
  • Allowable radius of connector’s bend in place of entering the cut-off point have to be not less than 5 mm.
  • Maximum size of front size is defined by allowable dimensions of stencil machine’s working area. The maximal dimensions of our front panels and keyboards are 490x650 mm.
  • Allowable quantity of keystrokes is not less than 1 million.
  • Time of bounce (tinkle) does not exceed 5 ms.
  • Abrasion exertion: 1 N.
  • Commutative voltage: minimal - 0.1 V, maximal - 25 V.
  • Commutative current: minimal - 0.05 A, maximal - 0.1 A.
  • For electroluminescent lighting of front panel elements: power supply is about 100 V (400-500 Hz) or 220 V (50 Hz).
  • Maximal contact resistance is 1.0 Ohm
  • Overall maximal contact resistance is 100 Ohm (it can be decreased according to customer’s request by increasing the width of conducting tracks).
  • Dielectric strength under the influence of electrostatic charges is defined by the film characteristics. For example, Lexan FR film (GE Structured Products www.structuredproducts.ge.com) used for standard process of keyboard’s outside has maximal dielectric strength 59 kV/mm.

Keyboards with tactile effect

The permanent use of some keys situated on the device panel usually gives rise to necessity for user to feel the subjective tactile effect while pressing the key. The tactile effect has come about through the dome shaping of the key in places where it has contact conductive groups in keyboard’s inner layers underneath.

The key may have any simple geometrical shape: circle, ellipse, square, rectangle. It is also possible to make a relief with any character on the key’s upper side.

The key height is in 0.3-0.6 mm range (it is possible to produce keys with up to 1 mm height with the use of special paints and thin films).

Key speed when pressed is equal to the form height (0.2-0.5) plus the distance between two conductive layers (0.2 mm).

Film thickness is 125 up to 300 µm.

Minimal pressing force is 3 N/sq.mm

Number of keystrokes depends on material.

The key shape dimension is not less than 8 mm. It complies with least diameter of the round key or minimal side length of square key.

Full colour printing is done on the reverse (bottom) side of front panel. Full colour drawing, inscriptions and symbols is applied to the reverse side of front film and therefore is not influenced by any environment conditions.