[Kindle 2 Teardown] E Ink, Epson Cooperate to Enhance Display Performances [Part 4]
After comparing the main boards of the new and old Kindles, Nikkei Electronics Teardown Squad set out to analyze the electronic paper.
The electronic paper used for the Kindles is manufactured by E Ink. As a so-called electrophoretic electronic paper, it is capable of black-and-white presentation and gradation expression with black and white particles moving up and down in microcapsules.
The electrophoretic method is used in many electronic paper devices being sold in various countries including the "LIBRIe," which Sony launched in Japan, "Sony Reader," which Sony Electronics Inc released in October 2006 in the US, and its successor.
What kind of differences are there between the electronic paper of the Kindle and that of the Kindle 2? We started by comparing their specifications. Both of the models have a screen size of 6 inches and a pixel count of 800 x 600. On the other hand, the number of tones increased from four to 16, and the response speed was enhanced by 20%, according to Amazon.com Inc.
We took out the electronic paper from the Kindles. It looked very simple because it did not have any back-lighting. Though the electronic paper was detached from the device, the information on the screen was retained, reminding us of the most remarkable characteristic of electronic paper, nonvolatility. The electronic paper was not flexible because it uses TFTs on a glass substrate.
The model numbers of the electronic paper modules used for the old and new Kindles were "3" and "4," respectively, indicating that the new electronic paper was one generation newer. We asked a person familiar with the industry about this change. He said, "the change from version 3 to 4 is not worth noting. It's a very slight improvement."
Then, how were the number of tones and the response speed (speed of turning pages) improved? We checked the controller ICs used for the electronic paper.
The controller IC of the new Kindle seemed to be the chip that was mounted on the main board and printed with the logos of Seiko Epson Corp and E Ink. On the other hand, that of the old Kindle was probably the one that was located under the SD memory card slot and printed with "Apollo."
"The controller IC co-developed by Seiko Epson and E Ink helps make the most of the E Ink's electronic paper, improving the display performances," the person familiar with the industry said. "The Apollo found in the old model is an controller IC that Royal Philips Electronics Inc developed for Sony's LIBRIe."
It seemed that the number of tones and the response speed were improved by replacing the controller IC.