Originally Posted by rmz76
Very interesting article even if it is a bit over two and a half years old. It describes two methods of achieving white through LED technology.
1. ...White light can be obtained from an LED source by applying a phosphorous material coating on top of a blue or an ultraviolet emitter. The actual phosphorous material composition, its thickness, and its placement are currently the subject of extensive studies by all the major LED manufacturers.
2. ... There is another way to obtain white light from LEDs by accurately mixing the light from three color emitters: red, green and blue (RGB) in the right proportion to obtain not only a white light, but also the desired color temperature.
The LED technology developed by Luminous found in the Samsung models is based on method 2, but I bet this article is the root of this whole rumor about phospher coating on the LEDs used in these sets, because some LEDs do operate that way... just not the LEDs developed by Luminous for this application.
Regarding the uneven wear of the LEDs, the article notes research was being done at that time, it's possible current LEDs used are immune. Let's assume they are effected, perhaps that explains why Samsung has only rated these televisions for 60,000 hours when the LEDs themselves are rated at 100,000 hours? This is a very interesting discussion. I've asked Luminous for comment.
Let's assume the LEDs found in the Samsung models may be susceptible to color drift over time aren't we really blowing this out of proportion? In 2007 the author notes this will happen 'sometime within 50,000 hours' modern LEDs are rated for longer life than those found in the 1st generation Samsungs and they are capable of producing better contrast (this was discussed when Samsung introduced the 67" model in 2008) it's plausable the problem still exist, but let's say around half of the 60,000 hour point (30,000 hours/15 years) the drift is to a point that the set can no longer be calibrated to standard and the set needs service.
Well, the LEDs cost about $130 each (there are three of course). Service manual on the Samsung's include detailed instructions on how to replace the LEDs. Parts + labor should be less than $600 which.... Which would still be about 1/4 of the cost paid to buy the set new, but in 15 years who know's what we'll have as an option in the market....
Consider the cost of bulb replacement for non-LED displays (and the inevitable color wheel replacement cost) over a 30,000 hour period, consider phosphor wear issues with Plasma (includng potential burn-in as a result) and the backlight weakening issues with LCD. There is no perfect technology, but I believe when you add everything up LED DLP comes pretty close.
I don't think you are getting that the color drift in the RGB cluster is basically linear and starts day one. It isn't like you use it for 10 years and then suddenly have color drift. It gradually happens each time the LED is lit. There is a different amount of drift on each of the three LED's, so your color scale becomes inaccurate and must be recalibrated. One manufacturer of LED's says 1% color drift per year, but didn't define what a year was (is it 24 hours x 365 days, or something less). If it is 1% per year with normal viewing habits, then at D6500k, 1% is 65K. On most consumer sets, you will only get +/- 50K (25K if you are lucky) on a pro calibration, so adding another 65K to that may put it in the realm of visible to the naked eye (D64 or D66). Of course, if they meant 9000 hours by their one year statement, then an average user may not need to recalibrate for many years.
It is also temperature sensitive. So say you calibrate your brand new set. Well, a year from now, you have some dust accumulate, the fans wear and slow down a bit and internal temperature increases, or whatever. Now they have drifted from the previous calibration, simply because of a rise in heat that can be caused by several factors, including aging of the LED's.
Another factor that can effect color accuracy is voltage level. If your power supply weakens with time, it can change the operating voltage of the LED, which will alter the output of each color, potentially to different degrees for each color. This can lead to poor color mixing and inaccurate color temp. On a lamp based set, the bulb would output less light, but the colors would still be mixed in the same proportion, so you still have color accuracy (as far as mixing colors), just not the right color temp.
I don't think bulb replacement on non-LED sets is as big a deal as you make it sound. Both my previous DLP sets got 8000+ hours on the bulb, so that is 3-4 bulb changes in 30,000 hours, which is about the same price as swapping out the three LED's. Color wheel can be an issue. I had one that did fail and another that was still running along. Even if you have to replace it once in 30000 hours, that is only another $250. So LED vs Lamp Based DLP, there may not be much of a difference between the two, as far as maintenance.
Like you said, no tech is perfect. I just don't think LED DLP is any better in that department than LCD, Plasma, or lamp based DLP.