Technical parameters and applications of button shrapnel

Introduction to the button shrapnel The metal shrapnel on the film button is located on the conductive part of the PCB board (mostly located above the gold fingers on the circuit board). When pressed, the center point of the shrapnel is concave and touches the circuit on the PCB, thus forming Through the loop, the current passes, and the entire product can work normally. The classification of button shrapnel can be divided into four categories according to the product structure: 　　1. Single-layer structure This is the simplest structure at the beginning. The metal shrapnel is located under Mylar (a layer of PET with glue). Vent holes to ensure the basic feel and use. 　　Second, the double-layer structure is different from the single-layer conductive film, it has an extra layer of Spacer (spacer), the shrapnel is better attached to the Mylar, and keeps it Good contact, have a better feel. In addition, the vent holes on the double-layer structure conductive film can more effectively prevent the PET layer from being scratched by the burrs of the shrapnel, and also prevent dust from entering the PET layer. Technical parameter height of the button shrapnel: 0.28-0.45 mm 　　 stroke: 0.13-0.30 mm 　　 force range: 100-400 gf 　　 force tolerance: ±30 gf　　 rebound: >30%　　 product life: >1 million times salt spray test: v35± 2°C, 5±0.1%, 48H　　Working temperature: -20°C-50°C　　Working humidity: <100%RH　　Contact resistance: <1 ohm　　Anti-static resistance: <3 ohm　　Tolerance range: ±0.05-±0.15mm Application of button shrapnel Button shrapnel is mainly used in the membrane switches of rigid boards such as printed circuit boards, such as mobile phones, cordless phones, Internet phones, CD/VCD/DVD, radios, digital cameras, MP3/MP4, game devices, electronic dictionaries, etc. , Give full play to the three advantages of strong conductivity of the shrapnel, stable rebound, and excellent hand feeling. The surface treatment includes gold plating, silver plating and nickel plating.