Terminology of Silicone Rubber keypad

Terminology

Actuation Force (F¹)

The minimum force required to compress the switch to touch the circuit board so the action could be recognized.

Air Channel

Air path between switches to ensure the key can return to normal position after actuation. Normally design symmetrically for air release.

Base

The sheet material forming the "apron" for all switches on the keypad. The base ties or connects all switches on the keypad.

Bezel

The front panel (usually to be plastic or metal) that "egg crates" all rubber keypad switches and typically covers the base material of the keypad so it cannot be touched by human hands.

Click Ratio

The difference between the actuation force (F¹) and the contact force (F²) of a switch divided by the actuation force.

(F¹-F²)÷F¹×100%

This "ratio" is extremely important when life is calculated and positive tactile feel is required in a keypad.

Conductive Pill

The current-carrying contact (silicone rubber impregnated with amorphous carbon) under each key completes electrical connection with the printed circuit board when the switch is actuated.

Contact Force (F²)

The force a switch typically realizes when contact is made with the printed circuit board.

Durometer

Durometer means the hardness of switches and the base material (unless the keypad is a dual durometer keypad). The higher the durometer means the harder the material.

Stroke

Also called travel distance. It means the distance from bottom of conductive pill (contact) to top surface of printed circuit board.

Resistivity

Resistivity shows how strongly a given material opposes the flow of electric current. The unit is normally expressed as ohm-centimeters.

Web

The web area is the thin hinge between key and base that creates tactile feeling and stroke.

05/31/2023