DISCREET LED BACKLIGHTING

Discreet LED backlighting is created with strategically placed top fire and side fire LED’s as well incorporating a combination of reflecting and diffusing layers in the body of the membrane switch.

Advantages:

• Brightness.
• The most basic design.
• The product will be virtually the same thickness as a non-backlit keypad.
• Uniform lighting
• Overall life
• Cost

Disadvantages:

• The number of LED’s needed

FIBER OPTIC

Fiber Optic technology uses two or more layers of woven fiber-optic cloth forming a rectangular light-emitting area. The fibers coming off one end are then bundled into a circular ferrule and coupled to one or more LED light sources.

Advantages:

• Number of LED’s needed
• Overall life
• Uniform lighting

Disadvantages:

• Brightness
• Cost
• The thickness of the fiber optic panel affects the tactility of the membrane switch.

LIGHT GUIDE TECHNOLOGY

Light guide technology is based on transmitting light from an LED to a particular area or areas away from its location creating uniform backlighting. Light from the LED travels both inside and along the film. At the location where backlighting is desired, micro - dots are created at the bottom of the film so the the light traveling inside can be reflected towards the keypad icons. These dots consist of concaved hemispheres. To keep the lighting uniform, the farther away from the light source the backlit areas are the denser the dots are created.

Advantages:

• Minimizing the number of LED’s needed.
• The product remains fairly thin.
• Uniform lighting
• Overall Life

Disadvantages:

• Not as bright as discreet LED lighting
• Cost

ELECTROLUMINESCENT

Electroluminescent devices are fabricated using either organic or inorganic electroluminescent materials. The active materials are generally semiconductors of wide enough bandwidth to allow the exit of the light.

Advantages:

• None

Disadvantages:

• Life
• Brightness
• Affects the tactility of a MEMBRANE SWITCH
• The need for a dedicated electronic device or inverter