LEDs business
rhombus4
but some high-end models still cost
several thousand dollars.
The current success in LED-based
TV is being led by the Korean
electronics giant Samsung, and
Steele says that this company is
expecting fast growth of this part of
its business. Prices of its sets are far
less than those of Sony – a 40-inch
model can be picked up for just
under $1500, and some retailers are
selling a 46-inch version for less than
$2000. This means that prices are
still more than those for LCD TVs
with cold cathode fluorescent
(CCFL) backlights, but the additional
premium to pay for this technology
has fallen to just $700-800, and it is
projected to fall even further later this
year and into 2010.
Steele points out that Samsung has
entered this market aggressively, and
backed the launch of its TVs with a
marketing campaign that is reportedly Steele says that Samsung may sell adjustments to the driving conditions Sharp is one of
worth tens of millions of dollars. He as many as 2 million sets in 2009. of the device. This is complex, and it the leading
explains that this effort has been However, he tempers that by adding adds to the production cost of the manufacturers
motivated by Samsung’s decision to that it is difficult to provide an display. of LED-backlit
eventually exit the market for CCFL- accurate estimate of the company’s TVs in Japan.
backlit LCD TVs, which is sales for this year. Although In the past, TV manufacturers have Like Sony and
tremendously competitive and Samsung has shipped many sets to shied away from using white LEDs, Panasonic, it
operates on very small profit retailers, some are just sitting on due to their limited color gamut. has no in-
margins. LED backlit TVs promise to shelves and gathering dust. This is Traditionally, the white light output house chip
generate higher profits for the not surprising given the backdrop of from the LED results from combining production.
company, and help to promote the a nasty recession, and shops that are the blue emission from the chip with CREDIT: Sharp
Samsung brand. full of discounts on all forms of TV. that produced from excitation of a
However, if Samsung decides to yellow-emitting phosphor. This means
Why buy an LED TV? reduce the price difference of its sets that the emission in the red region of
The primary benefits of buying LED- over those built with CCFL the visible spectrum is relatively dim.
based TVs have shifted over the last backlights during the Christmas But this weakness can be overcome
couple of years. Originally the holiday season, then it could sell by using white LEDs that combine a
strength of this form of TV was substantial numbers of TVs in the blue emitting chip with red and
superior picture quality. Samsung, for final few weeks of 2009. green-emitting phosphors. “The
example, boasted of deeper blacks stability of the phosphor is
and outstanding contrast ratios in its Samsung has reduced the cost of its important,” explains Steele, because
2008 models that employed a direct LED backlights by using white LEDs, any variations in output will lead to
backlight approach. rather than a combination of red, changes in the color balance of the
green and blue ones. Color mixing white-emitting display.
However, in 2009 it is promoting the three sources is more complicated,
stylish thinness of its LED backlit according to Steele, because the Back lit or edge lit?
sets, which have moved to an edge- output from each type of chip shifts Steele says that Samsung’s first
lit approach. Both types of with time, and this alters the color design of LED-backlight TV included
architecture eliminate mercury in the balance. So a feedback mechanism a two-dimensional array of emitters.
backlights, and Samsung claims that is employed to constantly maintain This enables local dimming of the
the switch from CCFLs to LEDs can the optimum white light output, which screen, leading to excellent contrast
also reduce power consumption by involves measurements of the ratios. However, Samsung has
up to 40 percent. spectral output, followed by subsequently switched to an edge-lit
October 2009 www.compoundsemiconductor.net 39
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