About Printed Circuit Boards
More complex user interfaces require higher-density, more miniaturized components. In these situations, printed circuit boards (PCBs) and printed circuit board assemblies (PCBAs) are often brought into play. A wide range of layers and thicknesses are available, allowing engineers to address a wide range of design requirements. When combined with custom-molded, silicone-rubber keypads, the result is a unique and reliable user experience.
- High Component Density
- Multi-Layer Electronics Available
- Enhanced Electrical Performance
- More Design Control
- Rigid Design
- Requires Manufacturing Expertise
- Not Flexible
- Typically Thicker
- Requires Gerber Files and a B.O.M.
- Typically More Complex Design
Printed circuit board assemblies (PCBAs) can be single or multiple layers (up to 16 layers typical).
Using PCBAs in the membrane switch assembly affords many advantages to design engineers. Unlike a simple membrane switch featuring a tail that plugs into a device’s motherboard (which are always starved for real estate), PCBA-based switches provide another platform for electronics.
These secondary boards can be used to offload a portion of the circuitry to the switch, with the top layers of the board reserved for the interface and the bottom layers reserved for the product. Conversely, the PCBA in the switch can house all of the necessary electronics, eliminating the need for a motherboard altogether.
The typical base material for PCBAs is FR4, CEM-1 or CEM-4. A wide range of thicknesses are available, ranging from .020” to .13”. Depending on the materials and thicknesses selected, PCBAs can help provide back panel support, in addition to providing a base structure for components and circuitry.
Minimum trace width for gold .003”, and for hot air leveling .006”. Plating thickness dependent on material can either be 1 micron to 25 microns. Plating options include copper, carbon, nickel or gold.
These keypads help to deliver unique tactile feedback and a distinctive visual appearance. They can be custom-molded in different shapes, patterns, and colors to support user-friendly backlighting options.
Silicone-rubber keypads are ideal for industrial environments, where a bold look and a more rugged, robust interface is required. With the correct design features, they allow you to completely seal a product from moisture, dust, and other environmental conditions, and they can also provide a level of vibration resistance.