[B]When is an LCD screen LED back light white or white?[/B]
This week I have been researching the specifications for a new laptop. You can [URL="http://dpnow.com/forum2/showthread.php?t=13627"]read about this on the main forum[/URL]. I'm on of those that has to be absolutely sure of the specification before committing...
I eventually settled on a Dell laptop but I came upon an anomaly in the specifications. The screen was described as "[COLOR=Black]15.6in High Definition (720p) LED Display with TrueLife". I was looking at a laptop in Dell's Outlet shop which deals in refurbished models. On the main Dell online shop, brand new examples of this laptop have screens described as: "[/COLOR]15.6" (40 cm) High Definition (1366X768) [B][COLOR=Red]W[/COLOR][/B]LED with True-Life".
What's a "W" between friends? Unfortunately, I was aware of a recent development in LED backlight technology which is interesting and I started to wonder if the refurb laptop I was interesting actually had an inferior screen.
Basically, LCD screens (inlcuding TVs) used to have CCFL backlights - think of them as very specialised fluorescent tubes. In the last 3-4 yeards LED backlights have taken over because they last longer and don't use as much energy. It wasn't long ago that you couldn't get white LEDs. Then the first white LEDs were very expensive. Thankfully, prices have dropped and they are now very affordable and they are beginning to find their way into domestic lighting as alternatives to conventional tungsten filament bulbs and even low energy fluorescent lamps.
However, ordinary white LEDs aren't really 'white'. They are yellow LEDs that have a blue component to neutralise the yellow. They work well enough, but critical analysis can show a yellow spike in the colour response of such LEDs. More recently white LED backlights have been introduced that use red, green, and blue LEDs. These combine to produce a much more pure white light. On top of that the colour temperature of such backlights can be adjusted.
Some of Dell's higher-specifiation laptops feature RGB white LED backlighting - it's explicitly described as such in the specifications. So is 'WLED' another term for the improved RGB White LED? I contacted Dell via their online sales chat service but the answer was not conclusive. The chap was adamant, however, that if the spec didn't mention WLED then it wouldn't have a WLED screen. In other words, he was relying on the wording of the specifications rather than having absolute knowledge. Refurb Dell laptops are sold by third parties too and I found one such official Dell Partner reseller who was selling the same model refurbished laptop and the spec. DID mention 'WLED'.
I have concluded that the likelihood of Dell's term "WLED" meaning an RGB white backlight is remote because it's featured on low cost laptops. But a more relevant mystery is whether or not the one I was about to order had a 'WLED' backlight. The Dell sales rep said that because WLED was not mentioned, it would be only an LED backlight. But he could not explain to me what the difference was.
Anyway I have ordered the unit and so that's that. I just wish that screen technology could be more clearly described than it is. For example, the kind of panel used in a display can mean the difference between an average or poor display and a great display. Once manufacturer got great reviews for one of its monitor display models based on the fact it used a PVA panel. But many customers found that their units, which had the same model designation, had less good TN panels. So if you are buying a new laptop or monitor display - buyer beware!