15.4″ MacBook Pro: LED Backlight
Posted by: Jin on: June 25, 2007
As all of you know already, Apple introduced an updated version of its 15.4″ MacBook Pro. One of the main updates, from a display point of view, was the use of LEDs as the lighting technology for the LCD. The LED backlight implementation on Apple’s 15.4″ MacBook Pro seems to be the largest for notebook PCs. Typically we see LED backlights on much smaller notebooks such as Sony’s 11.1″ TR series.
The type of LEDs used in notebook LCDs are called white LEDs. These comprise of a blue LED chip with a yellow phosphor coating on the package. The two combine for white light. White LED prices have come down significantly but high quality ones still command a premium. White LEDs can save on power consumption as well compared to CCFLs. That’s why Apple has increased the time the 15.4″ MacBook Pro will last on the same batteries. I am sure firmware and software upgrades have helped somewhat. Another benefit of using LEDs versus CCFLs as the light source for LCD backlights is thinner LCDs. Of course, too thin means less durability without using expensive materials such as carbon fiber (Sony’s G series notebooks come to mind).
What’s ahead? It’s easier to implement LED backlights on smaller LCD screens. Apple is working on implementing LED backlights for all of its products (Steve Jobs said so in one of his monologues about the environment) and we can expect to see the smaller 13.3″ MacBooks with LED backlights sooner than the larger displays (iMac, 17″ MacBook Pro, Cinema displays).
4 Responses to "15.4″ MacBook Pro: LED Backlight"
June 28, 2007 at 11:18 am
Thanks for your comment torchh. The LED type used in the 15.4″ MacBook Pro is white LED. The white light is generated by a blue LED chip with a yellow phosphor coating. In terms of color gamut, white LED technology is about on par with typical CCFL technology at around 45% NTSC for notebook PC LCD panels. You are right in saying that with R-G-B separate LED chips the color gamut improves dramatically up to 100% NTSC and more. However, R-G-B LED backlights have, up to this point, required the backlight unit to be located behind the LCD and require some room. The notebook white LED “backlights” are actually located on the bottom side of the LCD and is a strip of white LEDs. Again, thanks for your comment!
[...] follows. I do recognize it is a gross exaggeration, but bear with me. Just a couple of weeks ago, Apple introduced an updated version of its 15.4″ MacBook Pro that incorporated a LED backlight instead of the usual CCFL backlight. Although we use the term backlight, on a notebook PC LCD [...]
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Excellent post.
June 27, 2007 at 9:58 pm
If done with this goal in mind, the most significant technical benefit of LED backlighting can be a better color gamut than that achieved with CCFL. The range of colors that the display can actually produce, called the color gamut, is a combination of the characteristics of the color filters in the LCD panel itself, and the backlighting. Most LCD displays–including anything Apple has made up to this point– have a color gamut that is significantly inferior to that of a good CRT display. If Apple has truly done it with “white” LEDs vs a combination of R/G/B LEDs (haven’t read enough to know which approach they took) they likely will not get all the improvement possible by using LEDs. I’ll wait for more informed readers–or someone who took the display module apart
–to advise what is inside. The entire LCD industry is headed in the direction of LED backlights, but it will take a few years to get there, so Apple still has some time to show their technical savvy in this area.