Product category - tactile dome switches mounted to a printed circuit board with graphic overlays

Graphic overlays are a thin clear plastic sheet, typically polycarbonate or polyester, screen printed on the rear side with graphic ink to form the graphic features, colors, legends and icons.  The front side of the graphic overlay has a protective layer of clear UV hardcoat that provides a finish that ranges from gloss to velvet texture and is mechanically hard and chemically resistant.  The graphic overlay is finished with a layer of pressure sensitive acrylic adhesive on the rear side and die cut outside edges and holes, if needed.  Many graphic overlays are also embossed to raise the key-field over each dome switch or form a raised ring around the key-field.  This style of keyboard may also include an solid metal EMI/ESD shield and mounting hardware such as studs, standoffs or brackets.  Some graphic overlay keyboard assemblies come with another layer of pressure sensitive adhesive on the rear side of the printed circuit board for mounting to the OEM application. 

A very thin 0.015 inch printed circuit board is mounted to the front of a metal plate allowing soldered LEDs and connectors used in a high-powered satellite up-link transmitter.

A thick 0.092 inch printed circuit board provides rigidity for the dome switches, 21 surface mounted LEDs and SMT high density connector used in a outdoor enclosure for satellite ground support equipment.

This keyboard is used on a mobile military power distribution panel and contains a back-lighted overlay where all graphic overlay features that are not black are illuminated using a fiber optic panel mounted between the graphic overlay and the PCB with tactile dome switches. The keyboard contains both an EMI/ESD shield as well as a transparent RF shield on the clear rigid display window.

Keyboard illumination is provided by a single bright white LED is mounted at the end of the fiber optic bundle. Keyboard mounting is accomplished with conductive pressure sensitive adhesive on the rear side to make a good electrical connection between the wrap-around EMI shield on the keyboard and the conductive mounting surface. Electrical connection is made with solid copper flat flex cable (FFC).

This electronic keyboard uses the same style of printed circuit board with dome switches on the front side but is mounted within the thickness of the metal support plate with a graphic overlay mounted to the front of the support plate.

A second printed circuit board with electronics and a high-resolution graphic display is mounted to the rear side.  Additional hardware including power switch, cooling fans and handles complete this assembly.

Product category - tactile dome switches mounted to a printed circuit board with molded silicone rubber boot without electronics

Molded silicone rubber boots can form the entire front of a keyboard or just selective keytop areas where the keytop areas protrude though a housing or bezel.  The silicone rubber boot is the pushing mechanism or actuator that pushes against the tactile dome to close a switch.  As the rubber boot is not part of the electrical switch operation and does not generate any of the tactile feel, the hardness of the silicone rubber is stiffer and doesn't have to flex much.  The harder rubber eliminates most keytop wobble and tearing found in conventional soft conductive rubber keypads commonly found in cell phones, TV and cable TV remote controls.  The silicone rubber boots can be selectively back lighted on individual keys or low level illuminated for night time use.  Molded rubber boots have a protective coating with finishes ranging from matte to gloss. The major difference between our silicone rubber boot construction compared to conventional conductive rubber keypads is our keyboard tactile dome switches are environmentally sealed and offer consistent very low contact resistance, very low contact bounce and no ambiguous feel to the user.

The keyboard shown in the this photo is shipped to our customer as shown and then mounted into the metal housing as shown in the two photos to the right.  The PCB is 0.092 inches thick  and provides rigidity needed to press the rubber boot against the metal housing to form a water-proof seal.

Each keytop is back lighted with bright, day-light readable LEDs that illuminate the center circular area on the keytops.  The construction is completely water and dust-proof and EMI shielded for a mobile military application.

The rear of the keyboard is shown mounted to the rear side of the metal housing using conventional screws and lock washers.  LEDs and I/O connector are soldered to the printed circuit board forming high reliability connections suitable for robust environments.

This keyboard has a silicone rubber boot protruding through openings in a metal mounting plate and graphic overlay on the front of the plate.  Four of the keytops are translucent silicone rubber and are back lighted with bi-color LEDs.  As the LEDs change color, the rubber keytop changes color indicating a different operating mode for this application.

The tactile dome switches and printed circuit board assembly is mounted to the rear side of the metal plate.  Although small, this keyboard is very tough and rugged.  Soldered LEDs and miniature surface mount connector are used for long dependable life.  Additional mechanical hardware is included for mounting a LCD display.

This small keyboard is less than 2 inches wide and mounts to the front of a hand-held test instrument.  The silicone rubber boot wraps around the edges of the printed circuit board so when the keyboard is mounted in a closely fit pocket with a slight recess in the instrument's case, the keyboard is finished off without any gaps. The printed circuit board is only 0.015 inches thick to conserve on the instrument's overall thickness.  The rubber boot features raised and stylized keytop areas and three translucent indicator areas that are back lighted with LEDs.  Electrical connections are made with a surface mounted FFC connector on the rear side.  This keyboard is mounted to the instrument's housing using pressure sensitive adhesive on the rear side.

Product category - tactile dome switches mounted to a printed circuit board with molded silicone rubber boot and with electronics

This product category is the same as above but includes electronics or displays. The rear side of the keyboard's printed circuit board is available real estate for adding electronics without the need for an additional printed circuit board. This technique provides a simple means of interfacing the keyboard to external electronics by use of a single small connector. Standard serial interfaces such as USB, PS/2, I²C, and RS-232/422 are available. Custom interfaces also include bus-compatible or customer-specified configurations. Again, all of the options and features of the tactile dome switches mounted to a printed circuit board with molded silicone rubber boots described above are available.

This keyboard is completely sealed when mounted in a water-proof laptop computer and is used outdoors where it can be subjected to aircraft fuel, saltwater, strong UV sunlight as well as normal dust and dirt. This keyboard is fully PC compatible with PS/2 and USB interfaces and includes a built-in MS-mouse compatible pointing device. The keyboard's encoding electronics for the switches and mouse are on the rear side of the printed circuit board the keyboard and is fully EMI/ESD shielded to protect the keyboard and computer electronics from strong RF fields.

This keyboard's applications is an industrial process controller.  The printed circuit board with dome switches and electronics along with a molded rubber boot are mounted to the rear of the metal housing with rubber keytops protruding through the front of the enclosure. One of the rubber boot's keytops is a pivoted oval navigation control with for dome switches below the control. Two of the other keytops are translucent and back lighted with bi-color LEDs to control the color of the entire key to indicate operation modes  The front surface of the metal housing is styled with true intersecting planes forming a double-sloped surface.

The rear side shows a single printed circuit board containing the tactile domes, control electronics, indicators and connector. The difference in front housing surface angles is accommodated by a sloped molded rubber boot instead of using two printed circuit boards mounted at different angles and a jumper cable.  Although small, this keyboard is very tough and rugged.  Soldered LEDs and miniature surface mount connector are used for long dependable life.  Additional mechanical hardware is mounting a LCD display.

This electronic keyboard incorporates the printed circuit board with dome switches on the front side and surface mounted electronics on the rear side. The printed circuit board and LCD graphic display are mounted to the rear of the metal support plate and a molded plastic decorative mounted to the front of the metal support plate. The multi-colored rubber keytops protrude through the metal plate and plastic nose piece. The electronic circuitry contains the switch matrix encoding, LED and LCD display drivers into a serial I²C interface. The keyboard mounts to the front of a 19 inch rack-mounted chassis and forms the entire front of the chassis. This entire keyboard assembly is a good example of a "bolt-on, plug-in" final assembly. This application is a satellite receiver at the front-end of a local cable TV provider.