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Old 12-06-2017, 19:07   #227 (permalink)
onlinebaba
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Quote:
Originally Posted by bajinchi View Post
Hi Guys,

I was lucky to get here, as I was looking information related with OCA equipment and I just read this thread.

Actually I do LOCA repairs, struggling a lot with LCDs with BACKLIGHT but the work can be done.

So, trying to help here, I found this 3M document about OCA, that maybe can help to fix the bubbles problem showing up after their removal.


I can´t post the PDF as I have less than 10 posts, so google this and it should be the first hit:

Optically Clear CEF TB qxd - 3M


And now the highlights I think are important here to solve this out:


Step 1: Baking

Samples can be baked at 85°C for 2-5 hours, depending on the plastic thickness; the thicker the plastic, the longer it takes to remove moisture

Are you guys “baking” the OCA before using them to remove moisture from it? Or it can be from the recently cleaned LCD and the moisture came from it? Or both? Or his step can´t be applied to the OCA sheet as it can melt?



Step 2: Lamination

In the document is made by hand with a roller…



Step 3: Autoclave

Temperature: 30-60°C

Pressure: 70-100 PSI

Duration: 20-60 minutes


I thought that there is vacuum inside the autoclave, not pressure… am I correct?

cellularman89 in process #8 do this at 55ºC by 20 minutes at 6MPA (no idea what MPA is…yet) Maybe a new setting to try?


Step 4: Durability

This step is meant for customers who would like to determine the effect of long term device exposure to high temperature and high humidity. Most moisture absorbing substrates (e.g. PC and PMMA) fail this process because they outgas at high temperature and high humidity creating bubble in the assembly. Step 1 above is implemented to improve outgassing problem.
Here is a typical accelerated process condition.

Temperature: 60°C
Humidity: 90% R. H.
Duration:12-72 hours


This should be to have in consideration if bubbles appear after the de-bubbling process? Weird... but it points back to Step #1 of the document...



Maybe someone with these tools can help to try this new settings described in this document recommendations and let us know if it helps?



Thank you guys.
Dear you read out 3m oca life testing parameters, and in other hand it's a UV oca, it's need uv after autoclave and it's hard Oca, after put in uv it's become very hard to remove
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