Who sells LED display polarising sheet?

Try Edmund scientific - they will have it. You really want a circular polariser if it is to prevent glare. A red filter also helps somewhat.

I don't think you are going to like the price.

--
Regards, 
Martin Brown

I knew I had some, and found it in a box mysteriously labelled "Chinese Parts".

I found a bit of the stuff but no packet.

I was sure it came from RS but no luck searching 'LED filter'.

So I Googled 'red led display filter' and found that it did come from RS but their own search can't find it. Unfortunately discontinued.

Farnell do it but at crazy prices:

Might be worth contacting the source directly:

This might help:

\an\pdf\an_1015.pdf

MK

Info on circular polarizers:

"Understanding Polarizing Filters"

--
The best designs occur in the theta state. - sw

On a sunny day (Wed, 6 Jan 2021 15:03:00 +0000) it happened Michael Kellett wrote in :

If you go to ebay.com and type red LED filter sheet in the search window, I find 6$66 per roll for 40x60 cm, free shipping of course, and pick your color.

The OP needs to make sure he puts it on the right way--the quarter-wave plate side faces inward.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com

That stuff is certainly cheap (and it might well do for the OP's purpose) but it's not the real thing. (Unless "Lighting Effect Colour Filter Gel Sheet Change Colour LED for Home Party Stage" is a new branch of optical physics that I'd missed !

The stuff I have is very brittle and difficult to cut - so "Filter Gel Sheet" might be easier to use if you just want something vaguely red.

MK

We need a better definition of 3 segment red LED and OP's purpose. These simple filter paper would not be able to change the colour of a red LED. If the OP want to make 3 discrete LED to look more like a single segment, then a diffuser might work better.

That is interesting you can see my post to this thread but I cannot.

Some sort of server glitch or other happened to (wx)Macsyma thread too. I couldn't see any of the followups there from AOIE

--
Regards, 
Martin Brown

Actually, i see your post as the first post on Google group, but never see the OP's post.

Giganews seems to display the threads correctly...but it isn't free.

You get what you pay for I guess...

John :-#)#

somewhat.

fi

Your posts don't show up in google groups either:

I have no clue why they show up in XNews but not google groups.

I'd try switching to Eternal September:

I had very good luck with it for many years until I found my own ISP also covered newsgroups.

I'd also consider switching your news client to XNews. There are many links on the web. Configuration and setup is easy:

This is a lean, fast, no bloat news client. I studied all the available ones years ago and settled on XNews. It has never let me down.

I believe in picking good software that is reliable and performs well, but is past the date where authors keep revising it. This eliminates surprises and time wasted troubleshooting wierd problems.

For example, I run Win XP and never have to bother about updates. I run it on VirtualBox 4.04 which runs on Ubuntu 10.04. This version of Ubuntu was released on April 4, 2010. It will never change.

I run LTspice version IV. No problems with wierd updates.

I also run Win 7 on Virtualbox. It will never change.

Xnews will also never change, so it is an ideal candidate for reliable performance.

--
The best designs occur in the theta state. - sw

On a sunny day (Wed, 6 Jan 2021 15:58:23 +0000) it happened Michael Kellett wrote in :

True, not sure what the red filter in front of say red 7 segment displays is made of. But this should increase contrast if placed directly against a red 7 segment display Further away it will likely be diffused. What I have seen in front of such displays did not look very special... Staying with ebay, you can of course searh for similar, red plastic transparant sheet gives a LOT of hits

It is not 100 % true 'if it is not on ebay then it does not exist' but really close! :-)

Do you really need it? LEDs are a lot brighter than they used to be. Jack up the current a bit and use plain dark red or neutral plastic.

3 segment?

standard for gels used in theater lighting. Rosco has been the standard for decades.

.

Available in Theater Supply stores, and many Photo Supply houses as well.

One thing to be awae of is that theater gels typically transmit IR quite efficiently, so they won't melt and catch fire when positioned in front of a 500-watt incandescent lamp.

Joe Gwinn

Am 06.01.2021 um 14:59 schrieb Peter:

A nice custom supplier in europe is

with a wide variety of product segments.

I have a sample kit from the electronica exhibition (long time ago) with

14 different colored filteres named e.g. S103, S110, S221, S466 etc. all 4x13cm, maybe still available.

They seem not to provide cots parts however there are IMHO no mechanical standards.

--
Mike Randelzhofer, OHO-Elektronik

Its not about color filters, it's about reflected glare control.

Even old nixie-tube displays were improved by a circular polarizer; the idea is that illumination of the face of the display lowers the contrast of a dim light source, by back-reflecting of ambient light. So, a polarizer and quarter-wave delay (makes circular polarized light from ambient) which reflects back (in opposite-helicity polarization) becomes 90 degree linear polarized on the second pass through the quarter-wave plate, and is blocked by the polarizer.

This was very effective on nixies, LED displays, and CRTs, but completely useless with LCD displays (that have polarizers built-in, and wouldn't benefit from an extra layer of any sort).

On a sunny day (Wed, 6 Jan 2021 14:06:21 -0800 (PST)) it happened whit3rd wrote in :

OK, makes sense, Yes LCDs, try looking at your LCD watch with Polaroid sunglasses... I have some ASUS 3D glasses that use polarization switching..

man that is so long ago.... Ebay also has polarized sheets, do not see any red ones and those are probably linear polarized. I have some ebay Fresnel sheets that you can use as magnifier, or to focus the sun there is so much...

Yes; that is film. I was after something stiff, to bridge a window in the front panel.

Yes; it is to form a window in the metal panel.

A cheap solution I have used in decades past was just a piece of 3mm red perspex, which is ok for "lab instrument" kind of app but it doesn't do anything for sunlight readability which needs a proper polariser.