What makes our electronic paper displays different?
Earlier last week, I picked up a few interesting discussions on mobileread.com in regard to the iLiad display and how it is different from other electronic paper displays. But what makes our electronic paper display so different?
To get my facts straight, I had a chat with Dr. Alex Henzen, one of the founders and VP Research and Development and Patrick Janssen, Senior Optical Engineer.
To understand the difference we first need to take a closer look at the different components of an EPD and for simplicity sake we will separate the following components:
The Electronic Ink
The electronic ink is a transparent liquid with microscopic charged pigment particles captures inside micro-capsules. This electronic ink is processed into a sheet of plastic film for integration into electronic paper displays. The electronic ink used in the different e-readers on the market today is produced by the E Ink Corporation.
The Display
The FPL (Front Plane Laminate) is composed of a sheet of plastic film with the electronic ink material which is laminated to the active matrix back-plane, a layer of circuitry, much like the ones used in a TFT LCD display. The circuitry forms a pattern of pixels that can be controlled by a display driver. The manufacturer of the EPD for the different e-readers, including the iLiad is Prive View International. In case of iLiad, the TFT array is a proprietary design.
The Waveform
The electronic ink in the display needs to be driven. This driving algorithm is called a waveform. It is a wave or sequence of different voltages that repel or attract the white or black particles in order to pull either the white or black particles to the top. If the waveform only pulls the particles shortly white and black get mixed, which we perceive as grey.
The E-paper controller
The waveform is software that needs to be controlled by a chip or ASIC (Application Specific Integrated Circuit). This ASIC controls all the switches of the matrix and in simple terms tells the pixel when it is activated. This together with the waveform tells the electronic ink when and how it has to make black, grey or white. This is the beating heart of the electronic paper display. For the iLiad, iRex Technologies has developed the Delta ASIC which in contrary to the industries standard E-paper controller is able to handle 4 bits gray scales (16 gray scales).
Eye-Print
In order to optimize the performance of the EPD, iRex Technologies have developed the Eye-Print™ technology. The Eye-Print™ technology makes use of an advanced driving algorithm or waveform controlled by a custom build E-paper controller (ASIC), the Delta Chip, and the result is a seamless integration of the different components like the TFT panel, the electronic ink layer, the display controller and the user interface.
One of the main advantages of the E-Print technology is the ability to make an advanced and custom waveform that allows iRex Technologies to increase the number of grey levels that the display can handle but also the integration of other technologies like the WACOM Penabled™ technology that enables the writing functionality on the iRex electronic paper displays.
Another advantage is the ability to optimize the performance of the electronic ink material. Due to the complex creation process of the electronic material, which is a fusion of chemistry, physics and electronics, each batch is unique and can be slightly different in performance. Therefor each batch of electronic ink is analyzed by our optical engineers, who in turn develop a custom waveform for each batch that optimizes the performance of the material, resulting in a brighter display with better contrast and less ghosting.
Vizplex™
Earlier this year the E Ink Corporation has introduced the Vizplex™ Imaging Film. The key improvement of the Vizplex™ imaging film is a slightly faster response time. Currently iRex is in the process of testing the Vizplex™ material and developing a custom Eye-Print™ waveform for it.
In the coming weeks we will compare the display performance of the current iLiad with a Vizplex™ prototype and analyze the differences. So stay tuned.
illustrations - (c) 2007 www.kennisinbeeld.nl
14 Comments so far
I am quite interested to hear how the Vizplex compares to the older e-ink material.
Is your controller able to take advantage of the faster switchtimes without modification? Is it possible, that you could just simply exchenge the e-ink film? That could turn out to be very interesting.
One other nice thing about Vizplex is that it also comes in 10 inch size. Do you have plans for larger screens as well?
Some other company already announced such an upcoming model. Do you advise to wait for yours?
I couldn’t understand some parts of this article nnial 2007 - salvatore iaconesi - del.icio.us poetry, but I guess I just need to check some more resources regarding this, because it sounds interesting.
Electronic paper and e-book readers…
Just a little bit slow in catching up with this … but I was away last week at the Talis Insight Conference…
[…] that makes a device called the iLiad, an electronic paper device. Last week, Karel posted a nice overview of our display technology on our corporate blog. Fairly technical article, but I found it a nice, […]
Thank you for the article. This raises some interesting questions for me.
E-Ink claims that its current technology is 2 bits (4 levels) per pixel and Vizplex is 3 bits (8 levels). If iRex can get 4 bits out of two, can they get 6 bits out of 3 ? or only 5 bits out of 3?
And no where does anyone mention what is the limiting factor on DPI, is it the TFT substrate or the ink material? 160DPI is really nice but 200DPI was identified by IBM Research as the ‘knee’ of the curve in terms of eyestrain. > 200DPI and people percieve it as printed.
And finally, no mention of color. Not that I think color is the killer app but having color is another enabler for stuff like highlighting passages.
–Chuck
The number of bits depend on the waveform and ASIC and not the electronic ink (from E-Ink). In order to establish 4 bits, iRex Technologies has developed an advance waveform(Eye-Print)and a custom build ASIC (the delta chip). This is what makes the iLiad so different from other e-readers.
In a next article I will discuss other topics like color, flexible and Vizplex.
In the meantime please feel free to post any questions you have or information you like to see.
Yes larger screens pls.
I wonder if you are able to make a more compact model to compete with Amazon Kindle. I’d like to see HSDPA in there, touch-screen Browser like you’ve already got, foldable USB keyboard to input text quickly and more. Especially a bit lower price if possible would be nice.
Anyways, I have seen the iRex once in a tradeshow, and I released the video at http://techvideoblog.com/cebit/caro-irex-iliad-e-ink-e-book/ and it definately was one of the most amazing products I have ever seen and I cannot wait to own an e-book device based on some of your innovations such as the wacom, the open-source community, wireless and large surface, high resolution and better contrast.
Sorry if this message is a little bit off topic.
And following is corrected Hanlin eReader v9t link:
http://www.jinke.com.cn/compagesql/English/embedpro/prodetail.asp?id=36
Goody
Really good and really interesting post. I expect (and other readers maybe :)) new useful posts from you!
Good luck and successes in blogging!
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Oh! Perfect job!
Very good and helpful post.
I add your interesting blog in my iGoogle page!
We’ll expect many new interesting posts from you
It’s test.
I could’t post a message…