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Backlighting Options
Making User Interface Intuitive
Strategically placing lights inside an input device to illuminatethe backs of keys and functions is a technique, referred to asbacklighting. It makes keys and legends easier to read andproducts much more marketable. Careful consideration of
the trade-offs between the different backlighting applications,the product in design, and environmental requirements areall crucial elements to the product’s performance, reliability,
and fitness for use.Simply stated, a backlit
keypad is illuminated so that theforeground appears sharper in contrast with the background.The objective of backlighting technology is to achieve anoptimum balance between light output, power dissipation,
reliability, and operating life. A thorough understanding ofthe four main backlighting methods will help you select theright backlighting solution for your input device.
Backlighting Technologies
The objective of backlightingtechnology is to achieve an
optimum balance betweenlight output, power dissipation,reliability, and operating life.
Electroluminescence uses semiconductor crystals, known asphosphors, to convert electrical energy directly into lightenergy. As a solid-state phenomenon, it is the most efficientmethod known for converting electrical energy to light. Thehigh efficiency of this conversion minimizes power consumptionand losses due to heat or infrared emissions. Electroluminescent
devices consequently consume relatively little power andremain within two degrees of ambient temperature undernormal operation.Electroluminescent lamps are thin, flexible, durable, and canwithstand environmental strains. They provide for balanced
area lighting as well as uniform brightness. The extremelythin profile makes these lamps ideal for a wide variety ofapplications and allows design engineering the freedom to
put the light source directly where it is needed.Several factors to consider when a design suggests the use ofelectroluminescent lamps are as follows: electroluminescentlamps require high voltage and can create significant emissionswhen compared with alternative light sources. And the life ofelectroluminescent lamps is less than the use of light emittingdiodes. However, overall electroluminescent lamps provide our Electroluminescent Lamps (EL)
