LCD Switches and LED Switches Information
LCD switches and LED switches use an integrated liquid crystal display (LCD) or light emitting diodes (LED) to display text and graphics. They can be programmed to perform specific functions and provide choices for the selected operation. For example, a control panel with five rows of LCD programmable switches may contain a top row of 15 switches, each with a specific function. Pressing any of the switches in the top row changes the text or graphics on the other 100 switches, which are arranged in four rows of 25. Using this matrix, operators can access 1500 options in just two keystrokes. For their part, designers can reduce the size of the control panel and the number of switches per panel. They can also use an LCD programmable switch or an LED programmable switch to provide operators with feedback through backlighting. Some LCD and LED programmable switches can be programmed to show different colors. Others can be programmed to blink on and off, alerting operators to conditions that require attention. LCD switches and LED switches carry switch specifications and LCD or LED specifications. Switch specifications for LCD and LED programmable switches include electrical capacity or resistive load, contact resistance, insulation resistance, dielectric strength, mechanical endurance, electrical endurance, operating force, total travel, and operating temperature. LCD specifications for LCD programmable switches cover display operation mode, display condition, viewing angle, driving method, viewing area, pixel format, and pixel size. LED specifications for LED programmable switches include LED type, peak wavelength, viewing angle, optical power output, luminous intensity, forward current, and forward voltage. For an LCD switch or an LED switch with backlighting, color choices include red, green, blue, yellow, white, amber, purple, and violet. Supply voltage, supply current, input voltage, and output voltage are additional parameters to consider. For LCD drive integrated circuits (IC), timing characteristics include clock operation frequency, latch pulse frequency, clock pulse width, setup times, hold times, and rise and fall times. LCD switches and LED switches are made of materials such as glass-fiber reinforced polybutylene teraphthalate (PBT), a plastic used as an insulator in the electrical and electronics industries. Terminals are made of gold, brass, or beryllium copper and may be sealed with epoxy to prevent the ingress of dust, debris, and other contaminants. A rubber dome protects sensitive LCD switch components and provides tactile feedback to operators. Some LCD switches and LED switches feature wide viewing areas and support hundreds of different colors. Others support animated sequences and are designed for a minimum of one-million actuations. Typically, LCD programmable switches are used in medical equipment, electronic products, power plants, gaming machines, military applications, and flight simulators. LED switches are also used in many different applications.