|05-25-2008, 01:37 PM||#1|
Join Date: Jun 2007
Sourcing eReader Devices ...plus contrast ratio numbers
I happened to run across an interesting looking reader in that I had not seen this one before. The search led me to good old Alibaba with a list of many sources for readers:
Of course the comparison matrix looks like the comparison matrix here or the one here looks like the one there...either way it at least is an good indication of the features/functions of the readers. One reader does indeed provide contrast ration numbers. Apparent the older version of the display was a 9:1 ration and the new (vizplex???) is all of 12:1 (about the level of newsprint). For reference most LCD laptop displays are at least 500:1 these days. further reference numbers are Plasma and LCD TV's are typically around 1000:1 with the higher the ratio the more contrast the display has.
Luminance (measure of brightness) for laptop displays begin around 200-nits and go up to lawd only knows where. Generally the higher this number the better viewing in brightly lit areas. Still no matter how high this number, in direct sunlight the sun will win as nothing we have can outshine the sun...who knew? But this is where the transreflective displays improve outdoor readability by using the sun itself to light display.
I bring this up because I have had a difficult time finding anywhere that lists the eink contrast ratio numbers. Obviously we, in general, do not need them too great because even a printed books should be no more than about 50:1 and I suspect most typical paperbacks are around 15:1-20:1 (might be a tad lower though.) Newspapers are around 10:1.
Those numbers put even the lower contrast ratio eink panels at about newsprint level.
This paper does a great job of putting all these numbers and their relative meanings into a language "the rest of us" can understand by eliminating the more engineering/physics level details. The title of the paper is "What is e-paper?" I found it extremely good and learn a lot about several facts of eink displays.
Here is another link with contrast info details showing an 8:1:
I think for many of use, like myself I need something over 15:1 with DEEP blacks not sort of washed out blacks. Others can manage just fine at lower ratios of newspapers.
Overall even the Sony 505 which uses the newest production Vizplex display would seem to be about 12:1 ratio but from my direct observation and use the display looks sort of "washed out" and a tad fuzzy. I am not sure if it is a matter of the DPI or that the contrast ratio is decreased with the protective and anti-reflective protector/treatment the device gets. The display, naked, would have a better view-ability until the protective layer is added. Anyone who has a PDA/PocketPC can tell you when you add one of those anti-reflective (often called anti-glare) screen protectors, the display loses some sharpness and seems to dim ever so slightly.
Anyway, I was just figuring the more details we have the easier it will be to evaluate these displays before plopping down $300-$700+ for one. TO me the display is the primary matter followed closely by formats read. Navigation is important but I can get used to all but the worst software out there. After that it's a matter of what features the device has to make reading an easier thing...you know like a dictionary, some form of wireless access to be able to research interesting facts or persons and even technology in a book simply by highlighting the text then using the correct search tool for the info we need.
Anyway, have fun this was an interesting way to spend the AM waiting for my joints to finally re-join my body in a team effort to move.
EDIT: Something I left out was the implication that even if a particular eink panel might have say a 12:1 contrast ration, by the time the protective layers are in place over the panel the resulting ration cna be significantly lower, say around 8:1-9:1 which is almost too low to read for any lenght of time and actually see the words easily.
Last edited by brecklundin; 05-25-2008 at 01:41 PM.
|05-26-2008, 06:14 AM||#5|
Join Date: Jun 2007
maybe it's a HanEctLinAco device? All I know is I wouldn't buy one. Still it's a nice place to look for what is being offered in the wholesale & Brand-X supply chain.
|05-26-2008, 06:02 PM||#6|
Join Date: Sep 2006
Device: PRS-500/505/700, Kindle, Cybook Gen3, Words Gear
Yes it's the same hardware as Jetbook.
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