LEDs Get Brighter And Brighter Still

Dec. 13, 2007
Thanks to their higher outputs, the latests LEDs go beyond blinking buttons to easily assume roles in displays and general lighting applications.

Most components are on a quest to become the market’s smallest part or consume the least power. Yet LEDs strive to become the brightest, and with good reason. Nowadays, LEDs are called upon to do more than act as function and alert indicators. They can replace incandescent and fluorescent fixtures as well as automotive headlights and signals, plus tackle backlighting chores. So, the brighter the better.

Of particular importance are those designs and products that need to be readable at various angles and in high-ambient-light environments such as direct sunlight. Brighter LEDs also eliminate the need for numerous LEDs to do the same task, leading to more compact and less expensive designs. Of course, there is a wide variety of choices out there to do the job.

LEDtronics offers aqua green and red-green-blue (RGB) LEDs that promise to shine through the brightest blaze of sunshine. A discrete, 5-mm, standard-dome aqua-green LED, the LD200-0AG-15D relies on an indium-gallium-nitride (InGaN) diode employing an optical-grade epoxy to produce an illumination level of 28,000 mcd at a 20-mA drive current, making it highly visible even in direct sunlight.

The LD200-0AG-15D relies on a water-clear lens to provide a narrow 15° viewing angle, which may be desirable for various types of applications—for example, individual pixels in a large dot-matrix screen, full-color screens, moving signs, displays, mini lamps, standard bulbs, theatre décor lighting, pushbutton switches, telecommunications systems, medical equipment lighting, and backlighting.

While maintaining clear visibility in bright sunlight and delivering full-spectrum RGB illumination, the LEDtronics RGB-1007- 001 four-leg, through-hole LED sports a low profile measuring 4.9 by 6.5 mm with a wider viewing angle of 120°. Luminous intensities range from 230 to 750 mcd with operating currents between 20 and 25 mA depending on the color. The individual red, green, and blue diodes operate at wavelengths of 635, 520, and 470 nm, respectively. Overall, its average life span is 100,000-plus hours or roughly 11 years.

Building on the popular XLamp XR-E line, Cree offers green and blue LEDs that outshine their predecessors in the family. The latest green XLamp XRE LEDs are 70% brighter than the company’s previous green power LEDs, producing a maximum luminous flux of 87.5 lumens with a 350-mA drive current.

This advance rides on the heels of an equal brightness boost for the XR-E blue power LEDs, which are 70% brighter than previous versions too. Also operating with a 350-mA drive current, the blue components specify a maximum luminous flux of 42 lumens. Both enhancements enable the design of more efficient and cost-effective lighting systems that employ fewer LEDs.

Osram Opto Semiconductors has developed what it is calling the world’s brightest single-chip, surface-mount LED. Dubbed the Diamond Dragon, the super-bright device achieves up to 250 lumens (see the figure). Target applications include indoor and outdoor lighting plus automotive headlights and signal lighting.

The LED’s surface-mount package, which employs a silicone lens, specifies a low thermal resistance in the area of 2.5 K/W and a maximum junction temperature of 175°C. Both specs allow the device to be employed in applications where cooling the LED is not an easy task, such as small spotlights (bulb retrofits) and recessed down lights.

The LED can withstand high drive currents without the risk of damage, specified as 1.4 A typical with a maximum current of 2 A. Typical life span is in the arena of 50,000 hours. Additionally, this single-chip device employs the company’s ThinGaN chip technology along with chip-level conversion and accepts 5 to 8 W of input power.

The Diamond Dragon will be available in January in white with shades ranging from 2700K through 6500K as well as all standard monochromatic colors. In terms of product longevity, its footprint is backward-compatible with the company’s previous devices, ensuring an easy upgrade path for current Golden and Platinum Dragon users.

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