Contrast looks best at 170 degrees angle?

CommanderROR · 08-12-2006, 06:45 AM

I made a strange observation with my Iliad:

If I put it on a table and look at it froma n angle of nearly 180 degrees, the background is very white and the text is very black. This position would then be an optimal reading position, but of course you can't really read very well from that angle.

My idea is, that the improvement in contrast is due to a "thicker" layer of "display particles" between the eye and the backplate. If this is correct, then maybe a thicker eink display could display better than the current ones? Or is it the particle density?

Does anyone else notice this? i've been wondering about if for a while now and finally decided to ask the community about it...let me know what you think.

ath · 08-12-2006, 08:38 AM

Quote:

Originally Posted by CommanderROR

If I put it on a table and look at it froma n angle of nearly 180 degrees, the background is very white and the text is very black. This position would then be an optimal reading position, but of course you can't really read very well from that angle.

180 degrees from where? Incident light?

CommanderROR · 08-12-2006, 11:18 AM

170 degrees in relation to my line of sight...put it flat on a table and sit on a low chair...then you have it.

arivero · 08-12-2006, 12:00 PM

Brewster angle.

ath · 08-12-2006, 12:22 PM

Quote:

Originally Posted by CommanderROR

170 degrees in relation to my line of sight...

Uh ... ? You look at it at 170 degrees angle from your line of sight? (The mind boggles ...)

Quote:

put it flat on a table and sit on a low chair...then you have it.

That means something like 80 degrees from the normal, the 'straight on line,' of the screen. (170 degrees would be looking at it from below ... ) Perhaps I'm too literal-minded ...

Anyway, I see no difference between straight on, and sideways, myself. Could depend on the light source ... but doesn't seem so: I've tried daylight, fluorescent light and incandescent light -- I see no clear difference.
But of course that can't show up on the poll ...
(I evaluate the 'white' of my screen to approximately 65-70, if 0 = pure paper white, and 100 = ink black. That doesn't seem altogether good ...)

arivero · 08-12-2006, 02:36 PM

From the wikipedia, the Brewster angle is expected to be about 56 degrees off from the perpendicular. But it is not glass but plastic, and they are using some anti-reflection trick (or they should).

CommanderROR · 08-12-2006, 03:06 PM

you are right about the angles...I "calculated" my angle a bit incorrectly...

actually it's close to 90 degrees from normal...almost parallel from you "eye-line"

ist that clearer? I've never been good with angles...:-)

ElaHuguet · 08-12-2006, 03:49 PM

I agree with you, Commander, I think there's a BIG difference depending on light, flourescent makes it look a lot whiter (so does sunlight), and angle; in the kitchen, I left it on the counter and sat on a stool, and also noticed how good it looked.

CommanderROR · 08-12-2006, 05:14 PM

thanks Ela...^^

Finally somebody shares my belief...:-)

yokos · 08-14-2006, 07:10 AM

@ CommanderROR: I can't answer your poll, because my answer is not chooseable - i see no difference in contrast.

I tried very hard but I can't find any difference in contrast if I change watching angle. test setting: daylight on cloudy day.

donkaarlos · 08-14-2006, 01:39 PM

Hi,
I would think that part of the reason that contrast is higher, when looking from an angle is simply that "printed area dot density" increases, while in "unprinted" areas there are "no dots" that could look denser from an angle. The smooth surface and the slight gloss of the screen might increase the effect.

With printed samples similar effect can be seen. Try it your self or look at the enclosed picture. With the e-ink structure the effect might be stronger as the colour particals actually form a "3D dot" bellow the screen surface, instead of the 2D print surface. From sideview you might see the surface and a hint of the dot depth?

donkaarlos · 08-14-2006, 03:07 PM

Quote:

Originally Posted by CommanderROR

My idea is, that the improvement in contrast is due to a "thicker" layer of "display particles" between the eye and the backplate. If this is correct, then maybe a thicker eink display could display better than the current ones? Or is it the particle density?

My guess would be anyway, that increasing thickness wouldn't help ... increasing partical color contrast and partical density bellow the screen surface would help. With a given partical size and density one should be able to calculate, what is the layer thickness that can be seen from top. Increasing layer thickness beyond that would not help. One would guess that they have done a great deal of contrast and density optimisation work, when developing the display?

El Chupacabra · 08-28-2006, 06:48 AM

I noticed that while it was next to me on the table and I was uploading documents from the computer. It has an astonishing contrast.

pdam · 09-21-2006, 11:06 AM

Obviously at 170 degrees - mainly so you can say to the jealous person on the train next to you - "look you can still view it at an angle of 170 degrees - cool or what!"

View Poll Results: When does the contrast look best?
Seen from directly in front!	0	0%
Viewed from a slight angle!	4	36.36%
Somewhere between 160 and 180 degrees!	7	63.64%
Voters: 11. You may not vote on this poll

08-12-2006, 06:45 AM	#1
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	Contrast looks best at 170 degrees angle? I made a strange observation with my Iliad: If I put it on a table and look at it froma n angle of nearly 180 degrees, the background is very white and the text is very black. This position would then be an optimal reading position, but of course you can't really read very well from that angle. My idea is, that the improvement in contrast is due to a "thicker" layer of "display particles" between the eye and the backplate. If this is correct, then maybe a thicker eink display could display better than the current ones? Or is it the particle density? Does anyone else notice this? i've been wondering about if for a while now and finally decided to ask the community about it...let me know what you think.

08-14-2006, 07:10 AM	#10
yokos Pac-Man caught my iLiad. Posts: 807 Karma: 3595 Join Date: Apr 2006 Location: Germany; next to Baltic Sea Device: Boox Max Lumi, iRex iLiad (RIP)	@ CommanderROR: I can't answer your poll, because my answer is not chooseable - i see no difference in contrast. I tried very hard but I can't find any difference in contrast if I change watching angle. test setting: daylight on cloudy day. Last edited by yokos; 08-14-2006 at 07:24 AM.

08-14-2006, 01:39 PM	#11
donkaarlos Junior Iliad User Posts: 59 Karma: 10 Join Date: Jul 2006 Location: Finland Device: Irex Iliad GONE - kindle & Kyobo	Hi, I would think that part of the reason that contrast is higher, when looking from an angle is simply that "printed area dot density" increases, while in "unprinted" areas there are "no dots" that could look denser from an angle. The smooth surface and the slight gloss of the screen might increase the effect. With printed samples similar effect can be seen. Try it your self or look at the enclosed picture. With the e-ink structure the effect might be stronger as the colour particals actually form a "3D dot" bellow the screen surface, instead of the 2D print surface. From sideview you might see the surface and a hint of the dot depth? Attached Thumbnails

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08-12-2006, 11:18 AM	#3
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	170 degrees in relation to my line of sight...put it flat on a table and sit on a low chair...then you have it.

08-12-2006, 12:00 PM	#4
arivero Guru Posts: 607 Karma: 2157 Join Date: Oct 2005 Device: NCR3125, Nokia 770,...	Brewster angle.

08-12-2006, 02:36 PM	#6
arivero Guru Posts: 607 Karma: 2157 Join Date: Oct 2005 Device: NCR3125, Nokia 770,...	From the wikipedia, the Brewster angle is expected to be about 56 degrees off from the perpendicular. But it is not glass but plastic, and they are using some anti-reflection trick (or they should).

08-12-2006, 03:06 PM	#7
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	you are right about the angles...I "calculated" my angle a bit incorrectly... actually it's close to 90 degrees from normal...almost parallel from you "eye-line" ist that clearer? I've never been good with angles...:-)

08-12-2006, 03:49 PM	#8
ElaHuguet iLiad freak Posts: 339 Karma: 243 Join Date: Apr 2006 Location: Mallorca, Spain Device: iRex iLiad	I agree with you, Commander, I think there's a BIG difference depending on light, flourescent makes it look a lot whiter (so does sunlight), and angle; in the kitchen, I left it on the counter and sat on a stool, and also noticed how good it looked.

08-12-2006, 05:14 PM	#9
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	thanks Ela...^^ Finally somebody shares my belief...:-)

08-28-2006, 06:48 AM	#13
El Chupacabra Enthusiast Posts: 33 Karma: 10 Join Date: Aug 2006 Device: iLiad / Nokia 6630	I noticed that while it was next to me on the table and I was uploading documents from the computer. It has an astonishing contrast.

09-21-2006, 11:06 AM	#14
pdam Groupie Posts: 199 Karma: 100 Join Date: Aug 2006 Device: iLiad, iPaq, Psion5&7, Blackberry	Obviously at 170 degrees - mainly so you can say to the jealous person on the train next to you - "look you can still view it at an angle of 170 degrees - cool or what!"

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