Xenarc...Sunglasses...Problem

IntellaWorks · 06-07-2005, 10:58 AM

Thanks for taking the time to read my post. This maybe a weird problem however I think that it may be a possible design "flaw" in xenarc or any LCD screen for that matter.

I just finished the install of the xenarc 7" TSD lcd with a custom bezel in my truck. Things were fine and dandy for about two weeks because it rained here for 14 days straight lots of cloudy weather.(yuck)

The first sunny day I wore Polarized sun glasses (because I'm a fisherman at heart) When looking at my LCD through the glasses I could barely see the LCD screen. It wasn't that I couldnt see the screen because of the darker image my eyes get when looking through the glasses. But if anyone with polarized glasses has ever seen a "film" on the windsheild of on comming cars (especially vans). This is exactly what I see when looking at my LCD.

For those that have never seen this I'll describe what I see the best I can.

A multicolored film over the xenarc touchscreen that basically blocks any chance I have to see whats actually on the screen.

Using regular sunglasses, I can see the screen noproblem.

So what the crap ?

hanzacra · 06-07-2005, 11:01 AM

Don't wear polarized sunglasses in the car?

wizawuza · 06-07-2005, 11:04 AM

I think most displays are like that intellaworks. I have that problem as well. Heck, I can hardly read my radar detector when I'm wearing my polarized lenses (fortunately the sound coming out of that thing is all I really need).

I don't have sunglasses that wrap around too much, so I can still see the screen out of the corner of my eye without too much effort, so i just stick to that.. Sorry I don't have a better solution.

evandude · 06-07-2005, 11:06 AM

monochromatic LCD's use polarizing films as part of the LCD (that's how people do the inverted colors thing, swapping for a film with different polarization direction)

now I don't know enough about color displays, but perhaps they use a polarized film as well, and that would explain the issue.

not that it would help you much, but does the display look any different if you hold the glasses at a different angle? I would think that if you got the polarization lined up on the glasses and screen, it should look relatively normal... but then you'd probably be holding your head sideways

MatrixPC · 06-07-2005, 12:17 PM

I know this problem and it drive me nut.
Not only that but color Cell phone display also has the same problem.
And yet, LCD/Plasma TV also has this same problem too. That is the first thing that freak the hell out of me when I walk inside the house with a polarized sun glasses. WTF is wrong with my brand spanking new TV?

Bugbyte · 06-07-2005, 12:28 PM

Same problem for me. I just chalked it up to polarized sunglasses. The screen has some kind of polarization on it.

Jahntassa · 06-07-2005, 12:31 PM

Any LCD screen has a polarizing filter in it. This is simply the way it goes. Even with Computer monitor LCDs, watches... any of it. There's no way around it other than ditching the polarized glasses. Unless you can find the angle of polarization on your screen, and find someone willing to match it with your glasses..But, that'd be expensive, and probably quite hard to do..

IntellaWorks · 06-07-2005, 12:37 PM

So I'm really not going nuts here ? Seems like this is something that I just have to deal with, if thats the case then thats a major drawback for LCD touchscreens. Especially in cars, I guess I could wear normal sunglasses but darn it I really like my expensive high tech ones.

If you make an LCD screen that doesnt mess up while looking through polarized lenses you'd be a an instant millionaire... I'm sure the vehicle manufactures that have LCD's as the headunit stock are aware of this problem and if you make some sort of de-polarized glass or something (forgive me for my lack of technical terms with this subject) they'd probably put one in every vehicle.

Thanks for the responses folks !

DeltaFX · 06-07-2005, 12:40 PM

The screen has of course polarization. That's simply how it works.

Liquid crystals only work by changing the polarization of the light they transmit.

W/o Volt in the lcd:
Light comes from the cold cathod, pass thru a first polarizer (say vertical) then thru the liquid cristal. Light remains polarized verticaly, it wont pass thru the second polarizer (horizontal) : that pixel is black.

W/ volt in the lcd:
when passing thru the liquid crystal, light's polarization changes. It was vertical, now it is horizontal, and then can pass the second polarizer: that pixel is enlighted. (color is just a filter)

When you watch your screen, all photon are polarized but human eye do not see polarization. WIth your glasses, well.....

IntellaWorks · 06-07-2005, 12:48 PM

wow...

PatO · 06-07-2005, 07:01 PM

Some company made a notebook a while back with a unique "privacy" feature - they simply didn't add the top layer of polarizing film! (or something like that) It appeared to be a blank screen to anyone happening to glance at it, but put on polarized glasses and everything was clear!

So, get a razor blade out and peel off the polarizing filter! (remove the t.s. first, of course) And make sure your glasses are polarized in the same way the top layer is on your LCD (vertical or horizontal). Most glasses and camera lenses use circular polarization - which would cause really funky effects!

Troy McClure · 06-07-2005, 07:41 PM

Not entirely related to LCD screens but being an avid fisherman, turn your head 90 degrees, you'll get a whole different perspective when looking through the water. It also helps with the LCD screen.

If you're really into fishing and like to see EVERYTHING, try the Costa Del Mar Wave 580's. They cost a mint but I know I'll never go back.

This is one of the reasons I took the touchscreen off of my Lilliput. With the touchscreen on, it was almost impossible to see the screen wearing the glasses. Now that it is gone it's at least readable in bright sunlight and wearing the glasses.

Troy

zPilott · 06-07-2005, 09:53 PM

expounding on what troy said, with polarizing, there is one angle that will be completely opaque, and one that will be completely transparent (in ideal conditions). Polarizing is kind of like a grill that has a bunch of bars running parallel:
|||||
|||||
|||||
and a light wave (which is usually made up of light that is rotated in all directions) can only pass if it is perpendicular, or 90 degrees, to the grate.
When you have two polarized filters, you can see through both of them, if the slats are running the same way. If one is like the above, and another is like:
-----
-----
-----
you wont see anything.
because only light waves that are perpendicular can pass, if the grates are 90 degrees apart, no light can pass.

if it is like
/////
/////
/////
or
\\\\\
\\\\\
\\\\\
you can see through it, but it will be darker.