Wednesday, December 18, 2013

New Technology makes it to the store

So I was in Walmart's today, looking around while they filled my prescriptions.  Wandered over the the television display.  They are all flat screen, and this year, is the year of no bezel.  The fronts of the TV's are all screen, no ring of plastic around the edge (the bezel).  And they are bigger.  55 inch for $800.  And the labels all say LED (light emitting diode) rather than LCD (liquid crystal display).  This is a forward step technology wise.  The LED screens are a little brighter and a little more vivid than my LCD Sony (state of the art a few years ago).  LED's emit light by them selves, and are very efficient, say 80% of the juice in comes out as light.  An LCD doesn't make it's own light, it acts as a shutter, blocking or passing a light source behind it, (the backlight).  I'm not sure just how backlights worked, but I expect LED's to use less juice than the backlight uses. 
   The surprise to me, was this major technological step forward got all the way to retail shelves before I heard of it.  No mention of this appeared in any websites, trade rags, or blogs that I read.  Or if it did I missed it.


DCE said...

David, one correction: LED refers to the backlight. The TV's are still LCD panels, but the original CCFL (Cold Cathode Fluorescent) backlights have been replaced with LEDs. There are a number of advantages to LED backlights including thinner TV's (the CCFLs are much thicker), better brightness control, and for some models, better contrast ratios if adaptive dimming is used (some LED backlights have sectional dimming which allows for darker blacks - the LED intensity is decreased on parts of the screen where the scene is black). The LED backlights may also last longer than CCFLs, particularly since there are no high voltage supplies (CCFL requires anywhere from 1300 Vac to 1800 Vac to operate while LEDs will run anywhere from 36 to 48 Vdc). LEDs also provide more light per watt than CCFLs so they use less power for a given brightness.

True LED TV's are out there now, but are few and far between. They use OLED (Organic Light Emitting Diode) technology. Sony was the first out of the gate a few years ago with an 11" OLED TV (it was really a technology demonstrator), but production problems and OLED longevity issues kept them from going into full production until recently. (I believe SamSung has demonstrated a 55" and 100" OLED TV's recently.) At the moment they aren't cheap, with the 55" TV going for ~$5,000. OLED TV's are a lot better than the LCD's for two reasons, one which you have already mentioned: 1. They can be brighter because they emit light rather than blocking or transmitting light like LCDs. 2. They have a much wider viewing angle than LCD TV's, meaning there is no optimal viewing angle like LCD's.

My company has been experimenting with OLED displays for our test equipment because they draw a lot less power than the LCD displays we've been using aa well as having better contrast. The only downside to them is they aren't as viewable as some LCD's in sunlight, a definite problem for our test equipment.

Cell phones have been using OLED displays for years, but due to their small size and limited lifetime of the cell phone itself, OLED longevity wasn't an issue.

Dstarr said...

I stand corrected. Your knowledge of the subject clearly outstrips mine.

DCE said...

It's a common mistake. Even some of my engineering colleagues thought the same thing. Frankly, I think the TV manufacturers have been allowing that misconception to remain out there because it benefits them, at least in a marketing sense.