Introduction of FPC membrane key switch

Introduction of FPC membrane key switch

Metaldomearray is a PET sheet with contacts (including metal shrapnel, also called dome), which is used as a switch on circuit boards such as PCB and FPC, and plays an important role between the user and the instrument. The role of the tactile switch. Compared with traditional silicone keys, membrane keys have better feel and longer life, which can indirectly improve the production efficiency of various types of switches using conductive films. The contacts on the membrane button are located on the conductive parts of the PCB (mostly above the gold fingers on the circuit board). When the button is pressed by an external force, the center point of the contact is concave and contacts the circuit on the PCB, thereby forming a The circuit, the current passes through, the whole product can work normally.

Introduction of membrane keys

Membrane keys are the basic structure of "key + membrane", so the feel and characteristics of the keys depend on the design of the membrane keys. Considering the reliability of the separation and rebound of the switch contacts, the thickness of the film is generally selected at 0.-0.2mm as the best, too thin, the rebound is weak, and the contact separation is not sensitive. If the thickness is too thick, the response will be slow to increase the operation force. If the key body is larger, for example, when the diagonal length of a square key or the diameter of a circular key is larger than that of a circular key, use a film with a thickness of 0.15 or 0.2 mm. The film is slightly thicker and has a strong rebound. After the key body is pressed for many times, the film has a small tendency to relax, so as to ensure the normal operation of the contact. When the isolation layer is thinner, the thickness of the circuit substrate film should be thicker, and the too thin film is prone to self-passage of the contacts. Flat keys can use a slightly thicker film material, and the film used for circuit contact bubbling should generally use a 0.mm thick film, only when the diameter of the bubbling ball is large and the chord height of the ball top is small. In this case, a thicker film should be used. Membrane key is an essential structure in electronic key products. It is a built-in conductive film in metal spring sheet key products and conductive adhesive key products. The function of membrane keys is to play the conductive role of switches in key products. Conductive foils on circuit boards. The structure of the membrane button is very simple. After directly removing the contact cover and keycap, the membrane circuit and circuit board under the button can be seen.