Cutting down on glare w/ a circular polarizer

netchris · 03-03-2007, 07:03 PM

These circular polarizers are designed basically as 1 way light filters.

Say the polarizer was placed on top of the touch screen (which from what I know about our touchscreens, it should work since they are pressure touchscreens and the polarizer wouldn't be putting any pressure on the screen). The light hits the polarizer, bounces off the LCD, and gets blocked on the way out. The light coming from the LCD shouldn't be any dimmer with the polarizer on top of it because the LCD's light is already polarized.

With too much direct light on the display, it will probably still be washed out, but at least there won't be any glare..

Sound like a good idea guys?

elserpiente · 03-03-2007, 07:28 PM

the link your pointing to is not working, i believe you are referring to: http://www.polarization.com/shop/catalog/index.html
and scrolling down to "Circular Polarizing Sheets".

They look promising, it would be interesting to see one of these applied on an lcd touchscreen.

netchris · 03-04-2007, 11:25 AM

Quote: Originally Posted by elserpiente

the link your pointing to is not working, i believe you are referring to: http://www.polarization.com/shop/catalog/index.html
and scrolling down to "Circular Polarizing Sheets".

They look promising, it would be interesting to see one of these applied on an lcd touchscreen.

Ah you're very right. I've re-done the link to correct the error.

I might try one of these. They also sell some with an adhesive which looks nice, but then if this doesn't work I don't want it to be stuck on my touchscreen. I'll have to ask the guys at polarization.com their opinion on the matter.

I still need to get some of this stuff for my clock face for one, so I suppose it won't be too hard to justify the cost.

RickS · 03-04-2007, 05:01 PM

I bought a sheet to check it out, will post pics if it works.

netchris · 03-05-2007, 05:47 PM

Quote: Originally Posted by RickS

I bought a sheet to check it out, will post pics if it works.

Awesome, glad to hear it! I hope it works well.

Did you get the one with the adhesive backing or without?

RickS · 03-05-2007, 06:13 PM

I got it with the adhesive...figured it would be interesting to see how it affects the TS.

Motorcity · 03-06-2007, 12:30 AM

I don't think it will work. On a resistive touch panel, the sensor needs to be unobstructed to correctly identify the touch location perameters. Adding an adhesive backed filter to the top of the touch screen will most likely render it useless. And good luck removig it from the panel once it is applied. Having this film applied directly on top will create a larger surface area that receives the touch, since the adhesive will bond the touch sensor more closely and not allow for as much free movement. So if you touch a point now, the touched area is the diameter of your finger tip. With the film added, the touch area becomes the size of a quarter, or even a half dollar. should make for a very inaccurate touch. If it even works at all.
Yes, it might actually work. Who knows? But given what I do know about these panels, I highly doubt it.
Good luck.

2k1Toaster · 03-06-2007, 12:40 AM

Well the back of the panel I think should be ok because you could calibrate it out I think.

I don't know how it really works this way because it really is just 2 panes of glass, but when I got my replacement TS I put it in backwards, and no matter where I touched I got nothing. I flipped it around, and voila, it worked. So I don't know if my TS was just haunted, but maybe the back of the glass is ok?

And if it doesn't work, a replacement panel is only like $50.

Motorcity · 03-06-2007, 12:56 AM

Your touch panel is not 2 panes of glass. There is 1 pc of glass substrate as a base, a spacer layer, and 2 ITO layers (the touch sensor part) bonded together. Resistive sensors only work one way. That is why you could not get it to work when it was backwards.
http://www.elotouch.com/Technologies...howitworks.asp

Adding that circular polarizer to the glass side (non touch) of the touch panel won't work since the polarizer would be backwards to the viewer, making the effects useless.

2k1Toaster · 03-06-2007, 12:59 AM

well it was 2 parts something, I just figured glass.

But why would it not work on the bottom side? If you keep it facing the same way, basically the adhesive side would not be stuck, as long as it is between you and the lcd, it should be fine right?

netchris · 03-06-2007, 01:33 AM

The most glare comes from the surface of the touchscreen so for the circular polarizer to cut down on the most glare it will have to be on the top of the touchscreen's surface. (so your finger will be touching the polarizer)

Quote: Originally Posted by Motorcity

Having this film applied directly on top will create a larger surface area that receives the touch, since the adhesive will bond the touch sensor more closely and not allow for as much free movement. So if you touch a point now, the touched area is the diameter of your finger tip. With the film added, the touch area becomes the size of a quarter, or even a half dollar.

While it's true that the 'sensed' touch will be larger than without the polarizer applied, it's totally dependent on the stiffness of the polarizer. It's a pretty bold statement to go ahead and say exactly how big the size of the sensed touch is going to be, if it's even significantly larger. From what I know about polarizers.. they aren't that stiff. From what I know about touchscreens, they work best when used with a fingernail, so even if the sensed touch size was 10x bigger than the surface area of your fingernail on the screen, It'll still be pretty accurate.

Quote: Originally Posted by Motorcity

Yes, it might actually work.

There's the attitude to have!

Honestly though, RickS bought a sheet and anything we say until we hear back from him is just pointless speculation. He's going to test it out and give us the REAL verdict on whether this is a viable option or not.

Quote: Originally Posted by 2k1Toaster

well it was 2 parts something, I just figured glass.

But why would it not work on the bottom side? If you keep it facing the same way, basically the adhesive side would not be stuck, as long as it is between you and the lcd, it should be fine right?

You could just get the polarizer without the adhesive..

Motorcity · 03-06-2007, 01:59 AM

Quote: Originally Posted by netchris

The most glare comes from the surface of the touchscreen so for the circular polarizer to cut down on the most glare it will have to be on the top of the touchscreen's surface. (so your finger will be touching the polarizer)
While it's true that the 'sensed' touch will be larger than without the polarizer applied, it's totally dependent on the stiffness of the polarizer. It's a pretty bold statement to go ahead and say exactly how big the size of the sensed touch is going to be, if it's even significantly larger. From what I know about polarizers.. they aren't that stiff. From what I know about touchscreens, they work best when used with a fingernail, so even if the sensed touch size was 10x bigger than the surface area of your fingernail on the screen, It'll still be pretty accurate.

You could just get the polarizer without the adhesive..

I was refering to the fact that the adhesive itself would be the largest contributing factor as to the increase of the "touch" area. It doesn't matter if the polarizer film is very flexable. The fact is that once applied to the touch panels' surface, The touch sensor and polarizer become bonded as one, and the flexibility of both will be reduced. Maybe not as dramatic as I mentioned, but you get the idea. Like you said, all speculation at this point. Hope to read more after a real world application and testing is performed.

parksgm · 03-06-2007, 02:08 AM

Interested. And subscribed.

netchris · 03-08-2007, 04:38 PM

Well I don't have a circular polarizer (yet) but I tried placing a sheet of printer paper over my touchscreen and it still felt my touch just fine through the paper.

RickS · 03-08-2007, 06:12 PM

Got the film yesterday but it was overcast. Wife's b-day today so nothing tonight either. Will have time tomorrow and it's supposed to be sunny. The film is a little heavier and has a bit more tint than I expected but the proof will be when I get it applied.

I decided on the adhesive because it needs to be held in somehow (though you could sandwich it between the TS and the bezel) and I've used screen protectors on my PDAs for years with no effect on the TS capability.

Will post pics tomorrow...

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