Green LED is bright enough for large projector

Mar 17, 2011
Green LED is bright enough for large projector

Osram Opto Semiconductors has developed an extremely bright, green light-emitting diode (LED) that makes LED projectors in office environments possible. Projectors in conference rooms have to be very bright for viewers to easily see the large images even in daylight. So far, LED light sources have therefore been used primarily in pocket projectors, cell phones, or home cinema systems. The new diode, which is based on the Ostar product platform, shines twice as brightly as before and its luminous area is very uniform. Beginning in mid-2011 it will be used to open up the office projector market. The first components are now being delivered to customers.

Projectors superimpose images in the three primary colors red, green, and blue in rapid succession. Conventional devices use a special halogen lamp behind a rotating color wheel. LED projectors do without a color wheel because the diodes emit red, green, and blue light directly. What’s more, LEDs generate brilliant images with high contrast and high color saturation. They require less power and have a service life of about 30,000 hours, more than seven times as long as conventional lamps. In the past, however, LEDs have not been bright enough for office projectors, which have to supply about 2,000 lumens of light. The brightest pocket projectors now provide between 50 and 100 lumens.

The brightness of an LED depends to a large extent on the output of the green LED, because green light accounts for more than two thirds of the white light produced in such projectors. The new diode emits 410 lumens of light at a wavelength of 520 nanometers, which is twice as bright as lamps used in the past. This means it is now possible to build systems of multiple LEDs that have a brightness of 2,000 lumens, enough for office projectors with image diagonals of up to several meters. The component is based on the latest chip technology for high-performance LEDs. Blue light is transformed into green light by means of phosphor converters. This allows the developers to achieve twice as much light as with directly generated green light.

The Osram subsidiary Osram Opto Semiconductors, which is owned by Siemens Industry, is the only manufacturer to offer LED solutions for projectors in every performance class — from home cinema systems with an image diagonal of over 79 inches to tiny units that can be integrated directly into cell phones or MP4 players. Highly efficient lighting is part of the Siemens Environmental Portfolio, which generated around €28 billion in sales for the company in fiscal year 2010.

Explore further: Faster computation of electromagnetic interference on an electronic circuit board

add to favorites email to friend print save as pdf

Related Stories

Osram LEDs for Mini Projectors

Mar 04, 2010

New, particularly high-performance light-emitting diodes (LEDs) from Osram make it possible to build mini projectors. These LEDs produce enough light to project images measuring over one meter in diagonal ...

Brightest LED Puts Light Bulbs in the Shade

Jun 14, 2005

Osram has developed the world’s brightest white light-emitting diode. Known as Ostar Lighting, this LED supplies 200 lumens, thus literally putting light bulbs and neon lamps in the shade. Previously, the brightest LED ...

Red light-emitting diode sets new efficiency record

Aug 16, 2010

Osram Opto Semiconductors has raised the efficiency of its high-performance red light-emitting diode (LED) by 30% under laboratory conditions. This record-setting efficiency was achieved through optimization of the chips. ...

Saving greenhouse power with deep-red LED light

Feb 14, 2011

The Siemens subsidiary Osram Opto Semiconductors has developed a powerful light-emitting diode (LED) for use in the cultivation of plants. It emits a deep-red light at a wavelength of 660 nanometers, which ...

Recommended for you

A smart prosthetic knee with in-vivo diagnoses

Apr 22, 2014

The task was to develop intelligent prosthetic joints that, via sensors, are capable of detecting early failure long before a patient suffers. EPFL researchers have taken up the challenge.

Old tires become material for new and improved roads

Apr 22, 2014

(Phys.org) —Americans generate nearly 300 million scrap tires every year, according to the Environmental Protection Agency (EPA). Historically, these worn tires often end up in landfills or, when illegally ...

Students take clot-buster for a spin

Apr 21, 2014

(Phys.org) —In the hands of some Rice University senior engineering students, a fishing rod is more than what it seems. For them, it's a way to help destroy blood clots that threaten lives.

User comments : 0

More news stories

Is nuclear power the only way to avoid geoengineering?

"I think one can argue that if we were to follow a strong nuclear energy pathway—as well as doing everything else that we can—then we can solve the climate problem without doing geoengineering." So says Tom Wigley, one ...

Cyber buddy is better than 'no buddy'

A Michigan State University researcher is looking to give exercise enthusiasts the extra nudge they need during a workout, and her latest research shows that a cyber buddy can help.