Membrane panel

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The panel layer is generally made of fine patterns and characters on the colorless transparent sheet such as pet and PC less than 0.25mm. Because the main function of the panel layer is to mark and press keys, the selected materials must have the characteristics of high transparency, high ink adhesion, high elasticity and folding resistance.

The main function of the cushion layer is to closely connect the panel layer and the circuit layer, so as to achieve the effect of sealing and connection. The thickness of this layer is generally required to be between 0.02-0.05mm, with high-strength viscosity and anti-aging; in production, the special membrane switch double-sided adhesive is generally selected, and some are required to be waterproof and high-temperature resistant, so the cushion layer must also use materials of different characteristics as per requirements.

This layer adopts polyester film (PET) with good performance as the carrier of switch circuit figure, and uses silver paste carbon paste or gold paste on it to make it have conductivity. Its thickness is generally within 0.05-0.175mm, and the most common is 0.125mm PET material.

It is between the upper circuit and the lower circuit layer and plays the role of sealing and connection. Generally, PET double-sided adhesive is used, with the thickness ranging from 0.05 to 0.2 mm. When selecting the material of this layer, the overall thickness, insulation, touch and sealing of the circuit key package of the product shall be fully considered.

The use of back glue is closely related to what kind of material the membrane switch is pasted with. The common double-sided adhesive, 3M adhesive, waterproof adhesive, etc. are often used.

From layer to layer
Main parameters
Non-elastic type
Mechanical parameters:
Keystroke force: 2N ± 20%
Stroke: 0.21mm ± 15%
Contact type: silver glue
Service life: 10 000 000
Environment parameters:
Operating temperature: – 25 ° C to + 65 ° C
Storage temperature: – 30 ° C to + 85 ° C
Protection: IP 65
Spring type
Mechanical parameters:
Keystroke force: 2.5N ± 20%
Stroke: 0.48mm ± 15%
Contact type: SS spring+silver glue
Service life: 10 000 000
Environment parameters:
Operating temperature: – 25 ° C to + 65 ° C
Storage temperature: – 30 ° C to + 85 ° C
Protection: IP 65
Raised key elastic type
Mechanical parameters:
Keystroke force: 1 to 4N ± 30%
Stroke: 0.5 to 1mm ± 15%
Contact type: silver glue
Service life: 10 000 000
Environment parameters:
Operating temperature: – 25 ° C to + 40 ° C
Storage temperature: – 30 ° C to + 70 ° C
Protection: IP 65
Electrical parameters
Normal working voltage: 24V
Maximum working voltage: 50V
Minimum working voltage: 1V
Normal working current: 30mA
Maximum controllable power: 500mW
Contact circuit resistivity: 1ohm / cm (1mm spacing)
Dielectric strength: 250vrms
Insulation impedance at 100V: > 100mohms
Maximum contact rebound: < 5ms
Compatible with TTL and COMS circuits