LED Backlights: Good for the Environment, but Can They Also Be Good Business?
by Sweta Dash
Much of the discussion surrounding the use of light-emitting diodes (LEDs) as backlights in flat-panel displays (FPDs) has centered on the technology's ability to be mercury-free and consume low amounts of power – making them a viable "green" alternative to the backlights being used today. But can LEDs also be used to drive higher sales or higher profit margins?
Liquid-crystal-display (LCD) panel suppliers are increasing efficiency, reducing power consumption, and reducing objectionable lamp materials. Up until now, LED-backlight-based LCD panels have mostly served the high-performance high end of the display market, in the process garnering higher profit margins that have also kept the adoption rate at a low level.
But as the cost difference between LED and cold-cathode fluorescent-lamp (CCFL) based backlights are going down, the efficiency of LED chips are increasing, giving it potential to reach the mainstream market. Because the panel price of LED-based LCDs will have some premium over CCFL-based products, which will allow higher revenue growth to suppliers, the competition will grow stronger in future years so that their advantage may decline. What this means in the short term is that LED backlights are not only green, but they may potentially bring more revenue to the LCD market in the near future for notebook applications.
High Adoption Rates
Notebook computers are expected to enjoy the highest LED adoption rate among the three major large-sized-LCD application markets. By 2012, we expect LED backlights for notebooks to reach a 90% adoption rate – that's up from a penetration rate of about 4.7% in the fourth quarter of 2007 and forecasted adoption rates of 18% by the fourth quarter of 2008 and 42% by the fourth quarter of 2009. This will be driven by their slim form factors, lower weight, and instant-on capability, as well as their lower power consumption and mercury-free attributes.
Therefore, notebook-PC OEMs and LCD-panel suppliers are aggressively going after this LED-backlight market in order to take advantage of the high-growth revenues predicted for LED backlights and to capitalize on the "green" movement occurring throughout the world.
TMD was the dominant supplier of LED-based notebook panels in 2007. But Samsung, LG Display, AUO, CPT, and CMO all introduced LED-based notebook panels in the second half of 2007. TMD has been an early adopter of LED backlights because the company mostly focuses on 10–13.3-in. panel sizes for notebook computers. By the end of 2007, more than 50% of its notebook panels have LED backlights. At SID's Display Week 2008, numerous vendors showed LED-based notebook panels in various sizes. For example, Samsung showed 12.1-, 13.3-, and 15.4-in. notebook panels with LED backlights at Display Week 2008.
Most of these panels use high-efficiency LED chips. In general, high-efficiency LED chips can cost 10% more, but are generally 20% brighter. Also, high-efficiency LEDs do not require higher currents which helps in thermal management, reducing the need for heat sinks. In terms of lifetime, LED-backlight-based notebooks are getting 70k hours.
Despite the higher adoption rates of LED backlights, the yield rate of LED panels is still quite low. The LED penetration rate will be hampered by high costs. Panel makers have planned to increase the thickness of LED light-guide designs and use VESA-like technology to boost the yield rate and reduce the mechanical requirements.
White LEDs: The Low-Cost Answer?
The white-LED-backlight notebook-panel price gap vis-à-vis CCFL backlights will narrow to within $10 in the future, iSuppli believes. In general, branded-notebook vendors are requesting thinner light-guide plates for LED backlight units to be used in ultra-thin panels. But the lower production-yield rates for these thinner light guides are affecting the overall LED penetration rate for notebooks. CCFL light guides require a thickness of 2.0–2.2 mm, but for LEDs the requirements are 0.7–0.9 mm for ultra-thin notebooks, making it difficult to produce these in volume. Panel suppliers are asking that the thickness be increased to 1 mm, which will help to increase the yield rate. The current yield rate is estimated to be only 60%, but the adoption of thicker light guides could increase it to 75%. LEDs used in notebook backlighting currently have a brightness of more than 1800 mcd, and some LED suppliers have boosted the brightness to more than 2000 mcd in 2008.
The Japan Institute of Material Science has developed a prototype of a white LED composed of red and green phosphors and a blue LED chip. Used for an LCD-panel backlight, the white LED can have a 99% color gamut, which is considerably higher than the current level of 72% color gamut of a conventional LED.
In terms of price positioning, RGB LED backlights are still much more expensive than CCFL-backlit notebook panels, with $50–$80 price premiums, while white LEDs are targeted to be less than $25 higher than CCFLs in 2008. A 13.3-in. white-LED-based notebook panel uses 20% less power and is 40% thinner and 20% lighter than conventional products. Apple's new MacBook Air notebook weighs only 3 pounds, with a maximum thickness of only 0.76 in.; it features a 13.3-in. LED-backlight-based LCD panel. Samsung recently introduced a new 15.4-in. LED-backlit panel that features 10 times (10,000:1) the contrast ratio of a typical notebook PC display.
Conclusion
The opportunity is ripe for manufacturers and LCD-panel makers to take advantage of not only helping the environment, but making a profit along the way. LED backlighting presents vendors across the value chain with a way to revolutionize the FPD market without taking much of a hit in regards to sales and revenues. iSuppli expects that the notebook market will be the first market to utilize LEDs in a majority of its products, but as the technology becomes more ubiquitous, it is expected that we will see products adopt this technology across the board. •