Thread: iPad
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Old 05-12-2010, 06:10 AM   #66
Grimaud
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Une intervention que j'ai lu ailleurs
Quote:
I did most of my work in the CRT era, and I am not totally current on the latest in LCD technology. There are a lot of factors that combine to create eyestrain when viewing a screen, and they can be different for different people.

The average human blink rate is 19 times a minute. When reading a screen, it can go down to 4 times a minute. Also, it has been shown that the exposed ocular surface area increases. This means the eyes start to dry out, leading to vision and fatigue issues.

Another factor is the nature of print vs. computer displays which is not touched upon in this blog post.

A printed page iproduces a square wave image. A VDT display is a guassian image (not the same thing as the guassian filter in photoshop). This means that each pixel is a little brighter in the center, and tapers off in luminosity like a bell curve toward the edge of the pixel. It takes more focusing effort to focus on a guassian image, and when looking at a guassian display, a "lag of accommodation" is created. The net effect is that instead of focusing on the screen, you are focusing behind the screen, and have to use extra focusing effort to keep the screen clear. This constant refocusing occurs thousands of times a second, and leads to a sort of "ocular repetitive motion"(I am oversimplifying this). This was first discovered and published in a paper by Murch in 1982.(referenced in the link above).

As far as I know, LCD screens are guassian image displays. My guess is that E-Ink produces a square wave image, and that is why many readers find the Kindle more comfortable to read. I don't know what the iPAD display shows. As far as refresh rate, that was relevant in the older CRT displays, but irrelevant for LCD monitors.
Et le lien dont il parle : http://www.aoa.org/x5380.xml (la partie qui le donnait était en réponse à quelqu'un d'autre qui disait ne pas trouver d'études sur le sujet). Je n'ai pas eu le temps de lire cette page en détail par contre, histoire de vérifier si ce qu'il explique est réel.

Pour en revenir à l'iPad, soit Apple a un des soucis de stocks, soit la demande est forte, soit les deux : aujourd'hui, la livraison est prévue pour le 7 juin, pour ceux qui font leur précommande.

Last edited by Grimaud; 05-12-2010 at 06:12 AM.
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