DisplayMate evaluation of S4 versus iPhone 5 now up
First time that a mobile OLED has received an A rating from DisplayMate, and more importantly, there is the 20% improvement in power consumption which is what was forecast for adopting PANL's green (though he doesnt get into the details of the materials used).
A belated thanks to you for bringing the displaymate report to our attention. I had been checking his Mobile Displays page looking for it but he didn't bother to put a link to the report there for a whole week.
Just to be clear, is it your feeling that the 19% efficiency improvement (0.13/0.70, rounded to 20% in the text) reported for the S4 is indicative of the use of PHOLED green? I've been scratching my head on this one. Everyone seems to acknowledge that early this year Samsung planned to use PHOLED green and a non-Pentile matrix. When they (at the last minute?) decided to drop non-Pentile, what did they do about green? Here are some random thoughts
- If you check it against the chart on PANL's PHOLEDs - Power Consumption page the displaymate efficiency improvement result seems to be about half that predicted by PANL (I measure 27% power reduction, 37% efficiency improvement). This is the new chart PANL put up last summer, the first one to show that today's LCD is more power efficient than AMOLED with red PHOLED alone. I assume it includes the 29 cd/A red and 85 cd/A green introduced at that time.
- According to displaymate, the S2 display was 39% more efficient than the S1 and the S3 was 38% more efficient than the S2. All without any new PHOLED colors. If the S4 has PHOLED green there is no room for this trend of other improvements to continue. Is that reasonable?
- If the S4 has green there also isn't room for the 29 cd/A red. That red, a big improvement over the 24 cd/A red at the same coordinates they offered before, was announced by PANL at SID 2012. That was shortly after the S3 became available. I asked Steve A. last year if new red was in the S3 but he told me he couldn't answer that. I think that if S4 has green the numbers say then PANL must have given Samsung early access to new red.
- If the S4 has green, it raises the question of just how much efficiency was compromised by the use of a mixed host instead of pure PA
Did I miss a report that there was a version of this display that was non-Pentile? The 2nd hand reports I found of the original Anandtech info indicate that it was unknown whether that display was Pentile or not.
As for the power savings, here is a quote from a DB conference on Sep 12, 2012.
"What they get by adding green phosphorescence emitter is about another 15% to 20% less power utilization in the device. So it would then extend the battery but it is an incremental 15% to 20% power savings on the screen and your screen uses anywhere between 60% and 80% of your battery depending on your utilization."
If you look above the display power consumption table in the displaymate article, there is a graph that shows the spectral pattern for each of the displays. The reds are identical on the S3 and S4 but the green has definitely shifted. I cant say for certain that it is a phosphorescent green, but most signs point to yes. You are right though that all of the power savings would then come from green and it seems like there should have been further gains from other aspects of the system.
One other question would be whether the 29cd/A figure for red was achieved using a red host from PANL. We know that PANL has yet to sell that commercially.
- If the S4 has green, it raises the question of just how much efficiency was compromised by the use of a mixed host instead of pure PANL host. If mixed host cuts the green efficiency gain in half it would mean that Samsung would have an option to get more... but would have to pay the price to PANL.
Wake up to what? That after all the years and money, the best OLED display is now as good as the best LCD display from last year. Or is it that the OLED display is still less power efficient than the LCD display. Good thing Samsung put that giant battery in their phone. Apple won't go OLED until it actually is the best.