Advanced Imaging


Advanced Imaging Magazine

Updated: January 12th, 2011 10:01 AM CDT

Cool and Bright

Indoors and out, LEDs provide more light with less heat
The MicroLens light guide
© Global Lighting Technologies
The MicroLens light guide from Global Lighting Technologies lights nine discreet areas of this thermostat: the main LCD area, characters and directional symbols at the top and sides of the unit (A-F), and keypad buttons at the top and bottom (G-H).
Smart Force Linear Driver
© Endicott Research Group
The Smart Force Linear Driver from Endicott Research Group is used with the company’s LED rails. The driver is less than 8mm in height.
white LED  by OSRAM Opto Semiconductors
© OSRAM Opto Semiconductors
OSRAM Opto Semiconductors has added a new white LED to its Golden Dragon® ARGUS® family.
amorphous-silicon thin-film-transistor liquid crystal display
© NEC Electronics America
One of NEC Electronics America’s four new amorphous-silicon thin-film-transistor (TFT) liquid crystal display (LCD) modules featuring super-transmissive natural light TFT technology.
NEC 2.7 -inch display for mobile applications
© NEC Electronics America
One of NEC’s three new 2.7-inch displays for mobile applications. They offer high luminance and high contrast ratios.
A 4.3
© DuPont Displays
A 4.3" WQVGA OLED display printed by DuPont Displays using its own materials and containment technology. The LTPS backplane was supplied by CMO/CMEL Corporation. DuPont Displays

By Barry Hochfelder

Goethe said, "Someday perhaps the inner light will shine forth from us, and then we'll need no other light."

The brilliant German polymath's beer stein probably was half-full when he made that observation, but that day, regretfully, is no where in sight, not even in the imagination of a Faustian deal. So we'll still need to rely on natural light and the light that we create.

In 1802 Sir Humphry Davy created the first incandescent light by passing current through a thin strip of platinum. It was not, however, bright enough nor did it last long enough to be practical, but it was the first in a long line of efforts that ended with Thomas Edison's creation of the first practical incandescent lamp 77 years later. Since then we've seen fluorescent bulbs, neon bulbs and others. The latest rage is the light-emitting diode. LEDs are making inroads both indoors and outdoors, where, instead of just overpowering ambient light, it actually recycles it.

One spur is the European directive to eliminate hazardous substances, which pushes CCFLs out of the picture because of mercury content. Most experts agree that LEDs are the next best solution.

Other reasons? There is no exposure to voltage with LEDs. CCFLs strike at the start can exceed 1,200 volts AC and typically 600-800 AC run voltage. LEDs can drop to benign voltage of 20 volts DC. They eliminate arc-over conditions, which is important for medical applications where they have to be concerned with arcing or leakage that could harm the caregiver or patient. LEDs have perfected switching time at 100 nanoseconds, compared to 5 milliseconds for CCFLs.

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