How Phosphors Expand the Addressable Market for LEDs
Published: March 19, 2014 Category: Advanced Materials

The text of this article was drawn from the NanoMarkets report, “LED Phosphor Markets-2014” 

Phosphors are critical to the future of LEDs because they address the quality of LED lighting in fundamental ways:

  • Greater range of color – beyond combining blue LEDs with yellow phosphors to increase the quality of white light, there are opportunities for high-quality red phosphors to provide better color rendering.
  • Improved efficacy and lower cost – existing phosphors have been able to provide LEDs with 100 percent greater increase in LED efficacy and a 50 to 200 percent decline in price, and new phosphor materials may be able to do even better.

These characteristics of phosphors can help expand markets where LEDs are already gaining market share, such as general illumination, and also markets where performance concerns or consumer perception has limited the penetration of LEDs. Phosphor firms have an opportunity to make money out of this situation not just because they are an important enabling technology for LEDs but because existing phosphors are not necessarily up to the task at hand.  Some applications will require new phosphor materials with better performance.

Phosphors, LEDs and General Illumination

Advances in phosphors can grow the addressable market for LEDs in general illumination by providing solutions that help address the perception that LEDs are dull and cold.  This is one of the main reasons, why consumers avoid LEDs.

NanoMarkets expects reliable LEDs that can produce warm light and have long lifetimes will experience strong demand, and these will require phosphors that improve color rendering index (CRI) and efficacy. Without improvements enabled by phosphors, white LEDs will remain relatively unattractive, given their cooler color temperatures, allowing alternative lighting technologies to gain ground.

Phosphor suppliers and academic researchers are intensifying efforts to improve performance and are making progress toward enabling growth in this sector. They are going beyond traditional combination of blue LEDs and yellow phosphors to create white light that is more appealing in order to fully tap the market potential. For example:

GE is developing manganese-based red emitters with narrow line-width emission. These can overcome the problems that limit efficacy of existing broadband red emitters, namely emission in wavelengths beyond the visible spectrum.

New hybrid phosphors can help meet the demand for high brightness white LEDs. Europium(II)-dopes red nitrides combined with yellow cerium(III)-doped phosphors are promising.
Hybrid nitride/nitrogen oxide red/green phosphors are reliable and have high CRI, and production costs for these materials are decreasing.
Osram is combining blue LEDs with a green phosphor and combining it with a red or amber LED. This approach eliminates the requirement for the phosphor to produce red light, allowing Osram to use a green phosphor with high efficacy.

UV LEDs can be combined with red, green, and blue phosphors to produce white light. Mitsubishi claims a spectrum equivalent to sunlight using this approach.

Efforts like those described above, if successful and priced appropriately, may accelerate the pace at which consumers turn away from CFLs, halogens and the new breed of high-efficiency luminescent bulbs and embrace LEDs for general illumination.

LEDs and Television’s Problem:  How Phosphors Can Help

In general illumination phosphors present an opportunity to expand a nascent market for LEDs by making the quality of LED lighting more acceptable.  In the television market, phosphors can be the enabling technology to revive a mature market.

LED backlighting for televisions and other high-performance LCDs was the first applications for high-performance LEDs.  At first LED BLUs were a distinguishing feature for LCDs, but now all televisions and mobile displays use them.  So the market for BLUs is saturated.

However, NanoMarkets believes that a new breed of phosphors will be able to bring new life to the TV market by increasing the color gamut.  This could happen if phosphor suppliers can create narrower-emission phosphors.  Some of the phosphor materials in development for general illumination, especially red emitting phosphors, would also enable growth in the TV market.

In addition, new developments in phosphors could protect LED lit LCD displays from any competition that might appear from OLEDs.  However, suppliers will need to improve light uniformity across the color spectrum in order to succeed in the LCD space.

Niche Applications: Theatres and Museums

The high volume opportunities are clearly in applications like general lighting and displays, but some niche markets provide additional revenue opportunities that probably shouldn’t be ignored.

Consumer perception is critical in the theatre and studio lighting sector, and new phosphor materials may help pave the way for greater acceptance of LEDs in this sector.  The industry understands the energy and cost-savings potential with LEDs, but lighting designers feel that tungsten lights have an emotional appeal that LEDs do not.

Phosphor firms have the opportunity to make money by tailoring products for this segment. New phosphor solutions that provide precise control of blue, red, and far-red wavelengths may allow the theatre lighting industry to overcome its prejudice against LEDs and lead to increased penetration of LEDs in this sector.  Phosphors for this sector will have to be thermally stable and compatible with theatrical-grade dimming in order to succeed.

Cost is critical in the often cash-strapped theatre industry. LED suppliers will need to emphasize long-term cost savings – eliminating the need for frequent bulb replacement and lowering electric bills – in order to increase adoption rate. Of course, reducing up-front cost of LED bulbs wouldn’t hurt.

New phosphor materials can enable expansion into sectors that were previously off-limits to LEDs, such as museums. Blue light is absorbed rather than reflected by the yellows and browns of parchment, faded textiles, and ancient artifacts, which can cause damage. Innovative phosphor solutions, such as using violet or UV LEDs in combination with red, green, and blue phosphors to create white light, can help LEDs penetrate the museum lighting sector.

Companies are making inroads into getting LEDs into museums. For example, Osram announced that it will be retrofitting the lighting in the Sistine Chapel with LED-based fixtures in order to highlight the Michelangelo frescoes. LED-based lighting will enable higher luminance levels for iconic artwork while preserving the historically significant work and using 60 percent less energy.

Beyond the applications mentioned here, LEDs have the potential to have far-reaching effects in a broad range of diverse fields, and phosphor firms that develop new materials geared for specific applications in preparation for future demand may be rewarded.  We expect the greatest revenue growth by far in general illumination, from around $50 million in 2014 to over $250 million by 2021. LED phosphor revenues in other sectors are likely to be flat or decreasing over the same time period. But there are still opportunities to accelerate adoption of LEDs in these markets through the use of phosphors that can enable improved color control, better efficacy, and lower cost, allowing innovative firms to reap some benefit.

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