A Silicone keypad is designed to provide electrical contact and tactile feedback. The tactile feedback indicates and confirms that an electrical contact has been established.
The haptic or the tactile feel is influenced by three factors:
Force
Stroke
Snap
Abatek controls the above three elements by influencing the membrane geometry. The total assembly and actuators have significant impact on the haptic. To fully control all those elements it is necessary to run an own high precision tool making shop and production.
Huge experience in the keypad industry has over many years resulted in exciting solutions and great customer relationships. Mastering all aspects reflecting the desired force/way specification AND controlling the crucial assembly makes Abatek THE partner of absolute trust.
Mainly measured in Newton [N], sometimes in gram [gr]. F describes the necessary force to actuate a button/key. Almost every actuating force from >0.5 N can be achieved.
Stroke
Way/Travel (Stroke) S.
Measured in millimetre [mm]. It describes the way a key physically needs to travel until the contact pill touches the PCB.
In the HMI world three different stroke are known:
Physical stroke in section view
Stroke in F/W graph / Stroke to contact
Electrical stroke
Specifying the distance for example in the section view instead of the F/W graph can result in a malfunction in the assembly. This because the compression of the silicone is not considered in the physical stroke.
The electrical contact - on the other hand - depends stongly on the pill technology used and its technical specification. See contact technology
Snap
Snap.
Measured in percent [%]. The Snap and its tactile feeling defines the desired characteristic of the switch. It is a result of actuation force (F1) and contact force.
F2 (F1-F2)/F1*100 %
The Snap designed for a silicone keypad typically ranges from 0 % to 50 %. The tolerance for a Snap specification is the absolute deviation value of ±10.
Return Force
Return Force.
The return force is relevant tacking the key back to its starting point. Therefore a return force of at least 0.35 N is required.
Life Cycle
Life Cycle.
For most keypads a life cycle of 100'000 cycles is demanded. Abatek with its material knowledge and over 5'000 successfully projects will ensure that best cost-performance ratio is achieved.
The Abatek short stroke solution “ClickPad” replaces traditional micro switches.
The Abatek ClickPad system is an unique integration of the optimal metal dome into the keypad.
It offers the world’s best solution in terms of force, snap, acoustics, life cycle, preload, lighting, sealing, price etc.
In assembly the ClickPad can achieve a stroke between 0,4 – 2,0 mm and is characterized by a distinctive snap feel at the peak force despite the short stroke. Additionally it gives you the option to adjust the sound without losing the sharp tactile feel.
Measured in Newton [N]. It defines the necessary force to actuate the button/key. Every actuating force from 2.5 N to 12 N can be achieved.
Stroke
Way/Travel (Stroke) S.
Measured in millimetre [mm]. The stroke of a ClickPad is a combination of 3 factors:
1. Stroke defined by gap between actuator pin and metal dome. 2. Stroke defined by silicone compression 3. Stroke defined by metal dome Stroke in assembly s2 can be selected between 0.5 mm to 2.0 mm
Snap
Snap.
Measured in percent [%]. The Snap and its tactile feeling defines the desired characteristic of the switch. It is a result of actuation force (F1) and contact force.
F2 (F1-F2)/F1*100 %
The Snap designed for a ClickPad typically ranges from 25 % to 65 %.
Return force
Return Force.
The return force is relevant tacking the key back to its starting point
Applications like window lifter, steering wheel toggle, sunroof, camera, etc. require a 2 step solution. Version one has one electrical contact in combination with a spring function. Version two has two electrical contacts in one - see animation. Each particular actuation force and snap can be defined individually.
Redundancy
Secure the contact.
In order to secure the electrical contact in safety relevant application a redundant contact can be implemented.
High Force & Snap
High Force - High Snap - High Life Cycle.
Where a robust keypad with high tactile feel is required - for example levers in heavy-duty applications - Abatek offers a keypad with high actuation force together with a high snap without compromising on a high life cycle.
