Advantages and disadvantages of several common types of membrane switches
Membrane switch is a key function, indicator components, instrument panel as one of the operating system. It is composed of panel, upper circuit, isolation layer and lower circuit. When the membrane switch is pressed, the contact of the upper circuit deforms downwards, and the contact plate of the lower circuit is turned on. After the finger is loosened, the contact of the upper circuit bounces back, the circuit is disconnected, and the loop triggers a signal.
Membrane switch has the advantages of strict structure, beautiful appearance, good sealing, anti-moisture and long service life. Membrane switch in the use of the crowd, the environment, the terminal equipment, the structure and process are also different. Advantages and disadvantages of several common types of membrane switches:
1. Metal Shrapnel (Pot Chip) Type: Using metal spring as conduction medium.
Advantages: The button feels good, the strength is even, the stroke accuracy is high; The operation can hear a crisp sound, can clearly know the operation, to avoid certain equipment buffer time, and repeat the operation; The use temperature can reach -20 ~ 80 ° C
Disadvantages: When the liner is not flat or pasted in the bending radian is too large, the shrapnel may cause short circuit, misoperation and non-rebound.
Recommendation: Use on a flat, can withstand the strength of the key liner, or directly use the thickened PCB board as the line layer.
2. Hot-pressing convex handle type: After printing the contact surface with thin film material, the bump is rolled to form resilience.
Advantages: high life, can reach more than 500,000 times; Feel better, travel and strength can be customized according to customer needs;
Disadvantages: mold cost is high, need to open convex bud mold; Use in a high temperature environment may cause the key force to weaken.
Suggestion: convex mold open metal mold, can ensure the consistency of the key strength and stroke.
3. Flat light touch type: The contact point is printed with thin film substrate, without secondary process.
Advantages: high key life, can reach one million times; The conduction contact area is large to ensure the conduction rate.
Disadvantages: no operation feel, easy to cause repeated operation or misoperation;
Recommendation: The key spacing as far as possible, otherwise it will increase the failure rate and reduce life.
4. Capacitive induction type: The use of electrical conductors to induce conduction.
Advantage: Can be like capacitive touch screen, in a certain distance sensing action; The induction distance can be customized according to the design.
Disadvantages: The qualified rate of finished products is low, the surrounding electromagnetic interference is more sensitive, the design requirements are very high; Requires relevant electronic components and chip support.
5. PCB line type: Replace the film line layer with a PCB.
Advantages: high precision PCB circuit, welding LED more solid and reliable, lower resistance value; The thickened PCB line layer can be used directly as a liner.
Disadvantages: PCB is hard material and cannot be bent.
Membrane switch is widely used in electronic communication, electronic measurement instruments, industrial control, medical equipment, automotive industry, intelligent toys, household appliances and other fields. For several types of common membrane switch is introduced here, want to know more membrane switch can be concerned about Huahongchuang.
