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Switch Engineering

Switch Types

A switch is a device used to changeover electrical current flow within a circuit. Switches are first classified by the method of operation (manual or detect) and then by their function. Mitsumi manufacturers two types of switch products: slide type and tactile type.

Tactile Switch Structure

Function of each part:

  • Housing: molded insert comprised of an electrode terminal and resin
  • Dome: stamped part to generate contact signal and tactile feeling
  • Cover tape: cutout part that prevents contamination
  • Button: molded part that makes contact with the dome
  • Cover: stamped piece to secure the assembly
  • Actuator: cutout piece that makes contact with the dome
  • Cover film: cutout film sealed with laser welding

Slide Switch Structure

Function of each part:

  • Housing: molded insert comprised of an electrode terminal and resin
  • Slider: molded part with a knob to adjust the position
  • Cover: stamped piece to secure the assembly
  • Contact: stamped part to connect the terminal to the housing and generate a signal
  • Coil spring: part that returns the slider to the original position

Operating Mechanism

Tactile Switch
Slide Switch

*Displays non-shorting type. For shorting type, signal is both A and B ON.

 

 
A switch is activated when the mechanism is engaged and the circuit connection is completed. The mechanism can operate in various ways using a button, slider or even a rotating wheel. Mitsumi manufacturers tactile switches with buttons or domes, and slide switches for with a self return option. An engineer can help recommend the best solution for your application.

Tactility

Tactility is shown as F-S curve below that is used to graphically display the click feel of a switch.

Definition of each parameter:

  • Operating Force (OF1): maximum point of the curve before RF1
  •  Returning Force (RF2): minimum point of the curve between OF1 and OF2
  •  Travel: distance from start to RF1
  •  Click Ratio (CR): defined by formula (OF1-RF1)/OF1 x 100%

Waterproof Technology for Tactile Switch

A three step process is used to waterproof our tactile switches.

Laser Welding

First we apply laser welding to the cover seal in order to seal the top side of the housing.

Laser Ablation

Next, we use laser ablation to create dimples on the terminal. This rough texture promotes stronger adhesion for the resin between the top of the terminal and bottom of the housing.

Air Leak Test

Finally, instead of using typical IP68 test procedures such as water submersion, we integrate an 100% air leak test in the production line. Water submersion is not practical for products in mass production. By performing the air leak test, we can verify waterproofness while maintaining fast-paced production schedules.

Design & Development for Switch Sheet

Need a more customized solution? Our engineers can work directly with your team to recommend and design a switch product best suited for your application. The tactile switch sheets have a flexible design with optional features such as waterproof structure, stable click-feel and silent operation. These switch sheets are an economical solution for high volume applications that require longer cycle performance – specifically consumer electronics.

This simple structure consists of a metal dome with cover tape directly adhered to a PCB or FPC. The design is flexible and allows for customization. Customers can specify the dome diameter, cover tape color and thickness, dome layout and outline of the cover tape. Additionally, waterproof and silent operation designs are available.