They need to have an adhesive side. I dont think glue works. Also other ideas with double sided tapes etc is problematic, because they will introduce additional interference to the polarized light. Im also not aware of a "consistant" source for these polarizers (especially if you dont want to buy professional grade optical equipment). Sometimes cheap polarizers from the marketplace of your choice work well, but may be out of stock a few month later.

So I would say I need a 0° polarizer, right ? To be noted : with that monochromatic Toshiba T1900 laptop there is an option in the bios to reverse the grayscale, current picture is in non reversed mode.

vbug wrote on 2026-03-21, 17:06:

So I would say I need a 0° polarizer, right ? To be noted : with that monochromatic Toshiba T1900 laptop there is an option in the bios to reverse the grayscale, current picture is in non reversed mode.

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That looks good! Try moving the 0 degree one around to see what looks best - you can work out the precise angle from the lines on your original broken down polariser. For instance on a TFT where the angle is always 45 degrees, you'll see lines at that angle on an LCD with bad front polariser.

The DSTN displays used all sorts of strange angles, I think -5 or -10 degrees. To see what I mean, this one's a colour DSTN but still it's not 0/45/90: https://bjheins.wordpress.com/2015/04/01/fix- … ba-486-laptops/

Thanks, I'll try that, actually I'm wondering if I should use a 0° or a 90° one, look at the color of the screen border, white with the 0° and black with the 90°, so I don't remember what is the original color of that border. But I'm not sure I can compare with the original polarizer, it was completely destroyed, I only keep a very little piece but it is opaque due to the glue, and I don't remember what was the original side for that little piece.

Took me HP Omnibook 425 out the other day only to discover the monochrome LCD display has a nice dark circle in the middle. Are these things easy to swap out? i've never messed with a display before. The laptop is in excellent condition and i'm nervous about taking it apart and making a bad situation worse.

Not familiar with this specific model but this type of repair is rarely in the "easy" category. Besides the display assemby you will be deailing with the removal of different types of adhesives (scraping, wahing with ethanol etc.). One of the key challanges is to put on the new polarizer (after you found the right one - a big part of this tread). Even small specs of dust caught under the new film can be a big annoyance. So a dust free (or reduced) working environment is a plus.