ozstang,, will you have any left???

about (min) 4 inches sqaure??

I would like to test at trippy point with these type of polars

clive

mikelish: I forgot to mention that if you soak that overnight the rear PVA may be permeated. This will soften the rear PVA glue so you will need to be very careful.

Elken: I can't think of what key may be missing here. And I also don't see why calibrating with RGB B+W can be beat?

I just set up the cloth soak technique on a test panel. It is looking very good. I got the folded paper towel to 1mm to the edge of the polarizer, and no water appears to spill over the edge. It is also very easy to control and move around. One thing I should add is that you will need to spread the air bubbles out of the towel and that before you set it down you should let all extra water drip out. If this goes as well as it has so far, this should be highly doable. Not a drop has gone where I don't want it.

I should mention again that dunking a polarizer in water and using a cloth on just the anti-glare surface is not the same. First, using a cloth keeps the water away from other components, but more importantly it forces the water to enter through the top TAC. It then must permeate through that TAC until it hits the first layer of glue. This is the only layer we wish to soften. It is believed if we gave it significant time, that the water would then permeate through the PVA and finally into the next layer of TAC. My initial tests have shown that this takes much longer so is not a worry.

If you dunk a piece of polarizer, water will permeate through the rear TAC as well and at the edges to the whole laminate. Not good. Not at all what the cloth will result in. This will cause feathered weakness of the edges of the PVA, as well as a weakening of the rear bond of the PVA.

Mark.

Only if your panel is definitely a 45 degree panel. Some are 90. Some of the really fancy ones can be anywhere in between. I would definitely test a corner dunked into the projector to be sure what the ballpark is. There is only one truly correct axis.

Mark.

Mark it is easy,,, the polariztion,, is puerly about contrast...

you cant see the subtle change in rotation with colours,, just does not work...

you will have to trust me on this point,,, you have to remmeber that I have had this setup now since three weeks ago now. and been playing all sorts of variations,, IE: the sled has been reconfigured, at 10 times now,,

what i meant about keys is simply,, I have gone much further than just the stripping stage..

I have to detail it all properly, many false trails,,

and there is much more to the smarts board than on the surface too..

IE: actual panel control,,, one of my areas (skills) is to component level SMD electronics..


clive...

That is why I suggest that he work to achieve the best Black and white values he can. But I also posted the colors so if there is a discrepancy between the best black axis and the best white axis, that he can make a good intermediate choice by also seeing hue changes. Of course, this discrepancy would be caused by crystals that are over-twisting or under-twisting.

oztang65, if you have a sheet do not cut it down to triplet mounting. It is not as optimal. I can prove it. Hold two sheets up so they are crossed an no light gets through. Now tilt the polarizers around and you will see that light gets through at certain angles. Light focused on the triplet makes incidence at these angles.

Elken: no doubt you probably have a lot of good stuff in the works in terms of panel electronics. I can't wait to hear what you have discovered. I was only worried you were referring to secret knowledge of the latest removal technique.

Mark.

mm, you are saiyng some lcd are 90 degrees and some are 45 degrees (i guess you are saying the output polarization taking the base of the lcd as 0 degrees) in any case you are assuming the relative degrees between the rear and front polarizer to be 90 degrees, but i am not sure about it. I know there are some lcd called SUPERTWISTED that the relative degrees between rear polarizer and front polarizer is more than 90 degrees, this is for a better contrast technollogy.

But this should not be a problem to detect, since you know the 3dlens polarization angle (0 or 90) you can easilly work out both rear and front orientation on the lcd.

Just from quick observations, when holding up the polarisers to my LCD (the one I am now looking at while typing...) there is a noticable difference in the amount of light transmitted through each piece. The first, the POA1 gets very dark, almost completely black, but the POAT, (adhesive backed and labelled as 'Transmissive') is quite easy to see through (although still dim in comparison to a 'clear' picture).

It'll be interesting to see if the 'transmissive' one will be of any use at all??

I guess that's why they call it 'experimentation'...

I assume that 90° and 45° are purely in reference to the angle of the polarisation compared to the sheet rollout, or manufacturing, direction.

the adhesive one is worse specs at 3Dlens. I believe it is the glue's consecuencies. Did you thought the glue would be easier to reemplace, didn´t you? just paste and play.

mmm, I prefer the normal one (no glue). Anyway, you said you have to cut it at 45 degrees; you can take 2 samples from the wasted areas and check the crossed trasmitance when the glue is facing inside/outside and see if there is any improvement at all?

mark,

yes, I can confirm the water test on a test piece taken from the removed polarbear / a/g combo from a CMV-520D. After about a 2 hour dunk the a/g just came right off (at least what was left of it after my stripper attempt). There did appear to be some "grain" at that point. I left the sample in the water overnight and in the morning the polarizer slid right off the protective sheet. The water did nothing to the glue layer which attaches the polarizer to the glass of the LCD. Mineral spirits did little to nothing, except make everything stink. I find it funny that the first thing I tried was a papertowel soaked in water sitting directly ontop of the a/g (almost exactly as your current removal method), but after about an hour I gave up... the a/g wasn't even less brittle, so I went with the stripper... I wish now that I had just been more patient and confident with this method... maybe next time ! ... for now, completely stripped will give me more opportunity for testing purposes...

elken,
I would suggest testing every 30-60 minutes for the first few hours for your proposed test as is does not take long for the a/g to be able to remove. (of course I had already used stripper on this, so perhaps this is why mine came off so quickly, ie. < 2hrs)... ah, just re-read some posts there, seems nothing happend for you in water very quickly, but as mark suggested, perhaps something can happen withing a short time span, all I know is that the entire polarizer structure will come apart at some point, but I believe mark has already found this with his dunk test...

sonic,
No, I did no sanding at all... I see now that this may have been a better way to go.
The stripper I used was Savogran Heavy Duty SuperStrip.
Active Ingredents:
Toluene
Methanol (a.k.a. methyl alcohol)
Methylene Chloride

dantheman,
yup... probably should have been more patient with the stipping as well... at this point though I was sure that I was doing damage to the PVA through so many applications and scrapings.... as it turned out, I was not, I just needed to keep going. Hindsight is always great, but i'm used to it, I'm a trial-and-error kinda guy, and don't mind getting this experience first hand.... now, gotta check on the LCD to see if she's working ok...

what I don't know is how to get rid of all that nasty adhesive used to attach the polarizer to the LCD glass... that stuff does not come off with water, denatured alcohol, or mineral spirits.... or even stripper as far as I can tell... I may try some "goo gone" but need to check a test piece first...

thanks all.
cheers,
gs

"what I don't know is how to get rid of all that nasty adhesive used to attach the polarizer to the LCD glass... that stuff does not come off with water, denatured alcohol, or mineral spirits.... or even stripper as far as I can tell... I may try some "goo gone" but need to check a test piece first...
"

Im having problems getting this stuff off the polarizer, ive even tried goo gone (no effect)

The stuff I used is called "Oops"... how appropriate... and it worked quite well at removing the adhesive... just a few minutes and the stuff just kind rubbed off... still gooey, but removeable. A few wipes later and the adhesive was completely gone... this was only a 3x3" test piece, but I plan on using it on a larger one. Does not appear to effect the polarbear protective sheet.

"Oops" is marketed as "The All Purpose Remover"... I believe they also make paint removers, but this is not that one.
Active Ingredients:
Ethyl Alcohol
VM & P Naptha
Xylene
Monochloro Toluene

half of my glue stuck to the polarizer half to the glass, stripper on theglass and then cleaned it off with alcohol finally go it off the lcd but still haven't found anything to get it off the polarizer.....

Ill say it again.....try brake cleaner on a test panel it contanes nhexane
quote
"N-hexane is recommended for cleaning the adhesives used to attach front/rear polarizer. Reflectors made of organic substances could be damaged by chemicals such as acetone, toluene, ethanol and isopropylalcohol.

I am going to try it today to see what it does

http://www.lumenlab.com/forums/index.php?s...c=7882&st=1720#

Here's why I think Mark is cautioning against the "dunking" method.

Test piece is from a Sony PSOne 5" LCD . I removed the polar bear from the LCD. Then I put the polar bear in a bowl of water for 1 1/2 hours. I then used a razor blade to lift up the antiglare and I started pulling it off. It came off rather smoothly. But here is the results.



What I think happened is what Mark had said might happen. ALL the glue was loosened. So not only did the antiglare loosen from the polar bear , but the polar bear loosened from the plastic it is attached to . So when I started peeling back the antiglare some of the polar bear stayed with the plastic and some of it stayed with the antiglare.

Now we definately wouldn't want that to happen with our 15" and 17" LCDs.

So I'm with Mark on this one. NO DUNKING. Try his wet rag method first.

Hey All,
Im current talking to a person about optical coatings and sealants. He thinks that his company may be able to supply a solution for those folks less inclined to go with removal methods. He's going to fax me some information. Basically the idea would be to defeat the the AG layer with a self leveling, optically clear coating. It has a transmission efficiency of greater than 97% and can be applied using several techniques. Its also a non yellowing formula which can with stand temperature shifts between -60 and 250 degrees F. Its also UV resistant. Im figuring it might make a good alternative for those who are still on the fence. This particular coating is actually a bonding material, but the properties we are looking for right on the money. Cure time is estimated at 45-60 minutes and there is little or no outgassing, so less chance of bubbles or aberations.

I will try to keep you all posted.

Samuraijack

I had the exact same thing happen with a piece of polarizer as Jonjandran did. The rest of the polarizer actually just pulled off in little strings like the fibers in wood. I dunked a larger piece in water for 12 hours and the anti glare pulled off in one sheet. Right now I have a piece under a sponge to see how much luck I have with that. If the surface application works then this could be the best technique we have so far.

I can empathize with Mark's enthusiasm, however....

It still looks to me from the jonjan's and mark8261's results that the polarizer is much more sensitive to water than to stripper. Again, a solvent is a solvent. It doesn't matter if the solvent is enert to us or not. What matters is if the solvent is inert to the polarizers.

Everyone seems to be making the mistake of assuming that because water is inert to us and stripper is not, that water is easier on the polarizer than stripper. This does not seem to be the case.

I do not think one person who has gone the stripper method damaged their polarizer when they removed the a/g. However, from jonjan and mark8261's results we see that the polarizer can be damaged fairly easily with water, if the timing is off.

From my perspective the experimentation is great! Go at it. But don't make the assumption that water is better than stripper simply because you want it to be so. Look at the results OBJECTIVELY.

Edit: the wet rag method with stripper may well be more effective than the wet rag method with water, from what I have seen so far.

jonjandran 1.5 hours is a very short time, i left mine in for half the evening. it didnt peel up for me, it just slid right off .

Here is what I am talking about. In as little as 1.5 hours the polarizer was stripped clean - i.e. no more polarizer.

If you have to soak in a wet rag for about 12 hours for the water to soak through the a/g layer, then what happens if you accidentally comeback after about 14 hours. Will your polarizer quality be compromised?

If the stripper method requires a 4 hour soak at a minimum, but you come back after 5 hours, will your polarizer be comppromised. So far the data says no.

Is it easier to keep track of a project over 4 hours or over 12 hours? These are crucial parameters when determining the most effective method to use.

I guess in my post I failed to mention one important part. The polarizer that tore was only submerged in water for 2 hours. The one that peeled apart easily was in for 12 hours. If the anti glare can be removed with water from the surface via rag/ sponge etc. then I believe this method would preferrable to most. I have removed a polarizer from a dead panel, and although that went well, it would be a little more hairy when performed on a working panel. Sanding alone concerns me, and it also requires another expenditure. Water may not be the only way to skin a cat, but if it works it will solve many issues that we are facing.

1. No need to purchase the correct polarizer
2. No removal of glue (there was nothing left after the water dunk)
3. Controllable, no water has moved on surface outside my sponge area
4. No stress on the panel or control boards (possible stress from sanding or scraping)

It wont do anything for the removal of heat like Mark was looking for because the polarizer would still be attached to the panel. I think it is fine for people to experiment and find those other cat skinning ways, but I think it would be more widely excepted if it can be as less invasive as possible. The idea of the forum is to help each other collectively to make the best projector possible. My hats off to all who have taken those first steps to get to the point we are now. I cant wait to see whats on the horizon and will continue to read and support this thread as much as possible.

All just MY opinion and can take it as that.

Sorry folks, fell asleep for the night and missed the hallaballoo! Ethyl alcohol is a no-no with the PVA. The rest of the ingredients seem fine but I am inclined to believe you would get the same result with pure Naptha or Xylene (Xyol) alone.

Sanding, I believe, is the key to the stripper method. The top layer of the a/g is SiO2 (glass) particles bonded into the TAC. The stipper will work on dissolving the TAC, but has a difficult time permeating the SiO2 layer without sanding.

Phutton,

As much as I wish you weren't correct - I do. Caution is still the word of the day here, and the water dunk test is not a production ready technique as yet. BUT - it is one hell of an ingenious method and one that I give BIG BIG dibs to Mark for having discovered.

That being said, my experiments would disuade me from a complete dunking of the polarizer in water. In my test sample, munch like Jon's, the polarizer shredded after having been submerged in distilled H20 for 6 hours. There is no question in my mind that H20 is affecting the PVA -


[pic deleted]

[pic deleted]

Not to mention - my brain

Edit: Sorry. Just goofing off, didn't mean to offend Sonic.

Here, you can see the damage closer:

Click to view attachment

Since the piece was completely dunked, both the a/g polarizer and the rear-TAC polarizer bonds were compromised. More troublesome, is this shredding . This occured all the way through the sample in the same orientation as the end shreds. This, to me, implies the PVA is being compromised.

disturbing....

Sonic,

Are you...uh...flashing us.

whity tighties.

Sorry, these attachments are big, hence the multiple posts.

The polarizer/Rear-TAC piece:

Click to view attachment

The a/g piece:

Click to view attachment

Even after the sample dried overnight, I can see litterally hundreds of hairline cracks in the PVA, all parallel. If light is reflected off the surface, the polarizer appears to have an "accordion-like" texture on a microscopic level. I think this is what Mark was referring to as grain. It is very difficult to capture on film.

I think that this rag/saok methof might be applicable to other solvents such as Benzine, Naptha, and Xylene that are known to be PVA safe. The only question is -are these solvents able to permeate (or better yet, dissolve) the TAC??

The torn polarizer or the tighty whities?

What would worry me, is that amongst those two pictures, you noticed MY white tighties ....

As opposed to the white titties? Cause if those are yours too...Houston, we have a problem...

I noticed both...didn't want to offend.

However, if your girlfriend's fishing for compliments...

Somehow the key here has been lost. If you dunk a piece of polarizer it is not at all the same as the rag technique. The dunk technique was only a precursor to the experimentation. By all initial accounts I cannot get water to permeate the PVA.

The reason that the polarizers are shredding is because the rear TAC is also taking on water, and it permeates through to the rear bond. Not only that, there is water entering at the edges. This is why the edges are more compromised than the center.

My best hypothesis is the grain is water filling stress cracks from the peel up at the rear of the polarizer. They do not form if water never makes it through the PVA. Therefore they do not form with the rag technique. They do not seem to form if the polarizer is never bent.

These were all huge problems up until I finally was able to prove that water can permeate TAC. Having proved that, every one of these problems completely disappeared for the reasons mentioned in earlier posts.

You are absolutely right that the polarizer will be compromised irreparably by a full dunk. This is what I have been working to solve (I have seen every one of these issues many times now).

The rag does not allow the water to jump beyond a layer until it has permeated through the previous layer. That is the main point of the rag. It also is needed to keep water away from the electronics.

I am almost done an actual panel experiment. I will try ragging it for way to long. I am confident it will work out just fine. I almost threw out my permeation experiment because even after having the rag on the test piece for over 24 hours, no grain showed up. I assumed that to mean that the front bond was not being softened. But it was, and had probably softened at the 6 hour mark. That is a pretty massive window to work with (and I don't know how long it actually was). If this PVA is not permeable to water (as I have seen, but was not what was expected), then you have until the PVA biodegrades to remove the anti-glare.

Mark.

I don't think the point was missed.

We were just warning people not to dunk and encouraging more testing on the rag/sponge method.

The point wasn't missed at all. What I am saying is that there is a solvency effect with water and the polarizer. And I think it is rather significant. That doesn't mean that water can't be used successfully when the right procedure is followed. It just means that there is a higher chance of something going wrong or some small degredation of the polarizer occuring as compared to another chemical that is more inert to the polarizers.

It's good to have champions for the water technique. It means that water will be thoroughly tested. However, I just want to make sure that we don't get into the mindset that water is automatically safe for the polarizers simply because it is safe for us.

From a performance perspective, it should be analyzed objectively and relative to the performance of other chemicals. If all things turn out to be equal (or nearly equal), then the other characteristics of water should come into play, such as availability, price, etc.

sonic,
yea i would agree, that oops is not the "best", but it is what I had in-house, and although Ethyl alcohol is a no-no with PVA, there is the mounting sheet between the PVA and the adhesive that i'm attempting to remove. Water has done far more damage to the PVA layer than the oops has done. we're only talking about 30-60 seconds of application, then simply rubbing the adhesive off. Then taking a cloth damp with oops and wiping off any residual. after doing this, there is no signs of "grain" as is the case when working with water, wether dunking or spong (rag) method... both have compromised the PVA... that is my experience... although i'm not confident that something didn't go wrong with the rag water method whem working on one of my samples...

It seems it is not the water that is damaging the PVA. It seems to be the lack of glue on the rear TAC, and the peeling of these test pieces. That is, the evidence does not seem so much to be the PVA breaking down, but rather that the PVA loosing bond to it's protective backing and thus cracking apart.

I am not sure of this, but certainly the experimentation points more in that direction than in the water damages PVA direction. I remain open to both, but I just want to make sure people realize this is actually going very well so far. The fact that TAC is permeable is a huge break . I just didn't get the things are going well feeling from those posts.

As mentioned, I tried a cloth for over 24 hours, and the PVA was not even permeated. The rear bond was not compromised and none of these issues were seen even slightly.

I have another test piece of exposed PVA on it's backing that has been soaking for 3 days. Not surprisingly the PVA peels up in strands if you are not careful. However, the PVA seems just as strong as strands pulled from a short soaked piece.

Transmittance remain seemingly perfect, and as long as the section is not flexed, it remains solid. It does, however, suffer from the grain issue as expected (both sides met with water).

To add to the data: it seems the grain does not evaporate away. I have given a test piece almost 2 days now in warmth and they do not seem to go away.

Mark.

Hmmmmmm.....I guess that solves the long debate about "Boxers or Briefs"...

Sorry Sonic! I just COULD NOT resist...!

It is entirely possible that it is not the water that is damaging the PVA, but it is the stressing of the polarizer due to the peel off-process. Since the rag method doesn't involve stressing the polarizer by a peel off - it may very well not induce the grain that a total dunk does.

Mark, your contribution to this thread is immeasurable. Without your early optimism and technical prowess (not to mention sheer brilliance), this thread would never have evolved in the way it has. I have every confidence that you will come to a workable solution to this problem! I have not tried the rag test as yet - it is next on the list

What worried me about the dunk tests are all concerns that you have been grappling with for some time. Mainly, this grain / shredding effect on the polarizer.
We need to know if this is ocurring due to weakening of the PVA or the stress of peeling. We should not be disuaded by these results, but we need to get conculsive proof as to why this is happening. The problem with just visually examining the polarizer after the a/g TAC has been removed via the rag method, is that it is still bonded to the rear TAC. That may be masking PVA damage if there is any, becase the pieces would physically be held in place by the rear TAC.

Elken's current FULL dunk test will reveal more because his polarizer will not have been stressed at all. If his TAC layers slide off with an integral polarizer - you are most certainly correct. But this is an x-factor that we MUST find out about in order to declare the efficacy of this method.

Sonic: I absolutely agree. We need to figure out what those grain lines are to be confident in such a technique. The reason I am pursuing other solvents is because I do not want the PVA to be compromised in any way (scrapers, chemical/permanent physical change).

I should add that the grain lines and separation also appears on dunking (not ragging) with every other solvent I have tried. Even the known PVA safe mineral spirits.If the underside of the TAC gets wet at all the rear bond will be compromised. Can you say wether any water had gotten into the edges, or under the rear TAC?

I had a couple tests go wonky. One of my tests fell over while I was out and soaked in the spilt water. #*@!. The other was 2 layers of paper towel sandwiching the polarizer but not overhanging. I dampened the top one and left. Turned out I added too much water and it leaked into the rear towel. I may not have noticed this as it wasn't really that damp, but it was enough to permeate and mess up the result. @*#!.

The final test I am fairly confident did not go wrong. The very small section of rag sat in the middle of the polarizer square and the whole thing sat on a hard surface. I had to cut down the polarizer to the size of the dampened area before I had any idea if it had worked.

Mark.

Ahhh - VERY pertinent information. This does indicate that it is stress inducing the polarizer damage. The rag method may very well be the way to go ...

This is exciting - can't wait for more results!

indeed, I believe this is exactly what happened. I had duct taped the test piece to cardboard. Although the duct taped acted a water seal pretty well, the cardboard got saturated and wet underneath my sample, so indeed this would have caused the PVA layer to fail... due to whatever reason, there were the "grain lines" that were very evident.

Am i correct in saying that the layers go something like this...

LCD glass >> adhesive >> polarizer >> adhesive >>> anti-glare coating ??

and furthermore, the polarizer is something like this...

protective sheet >>> TAC >>> PVA >>> TAC >>> protective sheet
OR
protective sheet >>> TAC >>> PVA >>> TAC >>> antiglare ???

This latter one seems to be what i'm experiencing... once the antiglare is removed there is not much protecting the PVA except for the "backing" protective sheet and TAC holding the PVA flat... Any idea's on this, I know it was tossed around for a while, but not sure exactly what was determined, or whether it may be manufacurer dependent ??

Yeah, those are most certainly NOT mine.


And in her defense, the flash made them whiter than they actually are ...

The briefs were her's too

EDIT: j/k Sorry Tracy

However, if the grain lines do still appear, then they can be attributed to the water having permeated the rear TAC (if his substrate glue is permeable) and at the edges. This will also cause a compromise of the PVA to rear TAC bond.

Likewise, if his substrate glue is not permeable, then if we do not see the grain lines, it may not be because the PVA is unaffected by solvent. It could be that water never had significant time to react with the PVA as it could not enter through the sealed rear TAC.

What we need is a section of never bent 3dlens.com polarizer immersed in water. If grains appear we know the grains are caused directly by the water. It will take further experimentation to tell if it is the glue, or the PVA that is causing the grain.

I have pieced together a bit more of the picture of what may have happened. In our case, the grain only seems to form at the rear of the PVA. I believe this is because as you peel the polarizer up the rear side of the PVA must elongate the most, and thus that is the side that will fracture.

Mark.

I know there were idea's passed around about using photographic polarizers. Had anyone tested one of these ? Elken ? I remember reading about it, but wasn't sure if anyone had actually tried it.

This is what I had in mind... something like this.

Thoughts ??

ps. this would be used prior to the triplet with the LCD panel reversed.

That's all it takes. Only the presence of water, and it seems to suck straight in to the stuff.It seems:

TAC,
Adhesive of some sort,
PVA,
Adhesive of some sort,
TAC,
Acrylic adhesive,
Panel (glass substrate surface),
Acrylic adhesive,
Rear TAC,
Adhesive of some sort,
PVA (polarization plastic),
Adhesive of some sort (same as rear TAC),
TAC and integrated anti-glare.

It's that last one that is the key. You cannot remove the anti-glare without taking the integrated TAC with it. Thus what you are left with is the exposed surface of PVA.

Mark.

Unfortunately all the camera polarizers I have tried are not of the efficiency needed. The polarization grid is just spaced too far apart. I believe this is because film will not be sensitive to the purple that comes through, and thus in print the polarizer may as well have been of a much higher extinction.

I believe they get much better transmittance out of wider spacing.

It is possible that the color filters in our panels are filtering out purple, and that the same effect will be seen on projection. However, I think Elken has proven that this is not the case. Our color filters take to wide a cross section of the color they represent.

The other problem is that (while the debate is still open) I feel triplet mounting is not ideal. The polarizers seem to lose efficiency with many angles other than normal incidence.

Mark.

Okay, my already feeble brain is in overload. I don't understand this. Elken is submergine his entire panel in water. Why should there be any grain induced in the PVA in the absence of peel stress?

Mark, I'm not certain, but isn't the rear polarizer also sheathed in TAC layers like this:

TAC
Adhesive
Polarizer
Adhesive
TAC
Adhesive
Glass Substrate
Adhesive
TAC
Adhesive
Polarizer (Analyzer)
Adhesive
TAC w/ integrated a/g

??

There may not be. We still don't know if panel stress is causing the grain. What I am saying is if Elken does not stress a polarizer and grain still appears, it could also be caused by the rear TAC adhesive, and not the PVA. The theory there is that if water dissolves out the rear adhesive, the slightly wavy surface of the PVA is becoming visible due to the internal reflection and refraction.

I am also saying that a complete submersion resulting in zero grain is also not going to definitively point the finger at stress. This is because the substrate adhesive could be sealing off the rear glue from water. And if the rear adhesive is the cause of the grain, the grain will not appear.

edit: I simplified the rear polarizer layers just as I simplified the panel layers (glass substrate, color filters, mask etc.) as they are not really of importance... yet? . I added the new layers anyway.

Mark.

hey mark... if you remember someone posted earlier about some squares of polarizer from surplus shed, I just got some and while they are not suitable for projection(some scuffs etc) .... want me to throw one in water? nary a sign any glue has ever been near them and they seem to be only the polarizer(they seem cut from a bigger sheet, one one edge of one the is a small strip of clear plastic(as opposed to the grey of the polarizer)....