Not all E Ink is the same - Kindle uses "La Perla", the next generation E Ink to 50% contrast
When considering an eReader, make sure that you are getting a device with the latest generation of E Ink technology, known as "La Perla". Kindle our all new uses of the Pearl, which is in the best possible experience with the reading of 50% better contrast and sharper text.
PopSci.com called the display of pearls "Best of What's New 2010" a winner, stating that "the most impressive achievement of the latest Kindle (among others, including a reduced size and a reduced price) is its E Ink screen Pearl, which is just an absolute pleasure to behold. "
How Electronic Ink Works
Electronic ink displays work in ink, like books and newspapers, but show the ink particles electronically. People who see the display for the first time do a double take because the screen looks like real paper.
No eye strain - reads like real paper, not a computer screen
Kindle electronic ink display is ideal for reading, since it does not create eyestrain as reading in the traditional backlit LCD tablets or laptops.
Text clearer and sharper screen
Electronic ink uses real ink to create a sharp text printing, as similar to what is seen in a physical book.
Dull, even in bright sunlight
Kindle screen reflects light like ordinary paper, eliminating the glare created by the backlit LCD screen tablet or smartphones. Kindle can be read as easily in bright sunlight as in your living room.
Increased battery life
Electronic ink displays do not require power to maintain a page of text, allowing you to read for up to a month with a single charge rather than hours on a tablet or smartphone. This low power consumption also means that the Kindle, unlike a laptop, never gets hot so you can comfortably read as long as you want.
Read before bed without affecting sleep
According to a recent article in the Los Angeles Times, the sleep experts say that reading on screen with backlight jealously guarded before bed inhibits the production of melatonin, which is critical for a night's sleep. "The final lesson is that insomnia and electronic devices that emit light should not [be] mixed before bedtime... Kindle is better for sleep."
Why E Ink is easy on the eyes than the LCD?
Here are some of the technical reasons: Read More Here