LED display covers

Thread Starter

Wendy

Joined Mar 24, 2008
22,842
I was recently ordered a module that has blue LED displays, it is on a slow boat from China. Thinking of using this to filter the display through. Before I spend any money though, I would like to discuss any other options/ideas members might have? I am always open to new ideas.
 

AnalogKid

Joined Aug 1, 2013
10,057
Back in the 1970's, when LED displays were ***the*** hot thing, a red panel over red displays was very common. Then came research, and it turned out that the edges of the digits are more distinct behind a panel that is the color of the package around the segments - grey. IIRC, some of the research came from HP.

It might not matter, because the eye's lowest resolution is in blue. Relative to green, orange, or yellow, the edges of blue displays will be less crisp.

ak
 

bassbindevil

Joined Jan 23, 2014
422
The photos in the Amazon feedback show a transparent orange (though not very dense).

I'd figure that matching the filter colour to the display colour would give the best contrast. For red LED displays, I bought a piece of red transparent acrylic at a local plastics dealer. It looked very dark, but red passes through with very little attenuation. Unless you're in a small town, the Yellow Pages under "plastic" should find you a place that sells stuff like acrylic sheets and plastic resins and stuff. It could be worth checking the dumpster behind a commercial sign shop, or going through the front door and asking nicely.
 

Thread Starter

Wendy

Joined Mar 24, 2008
22,842
I am basically housebound, the only way I can get things like that is through mail order or Amazon or Walmart.
 

Thread Starter

Wendy

Joined Mar 24, 2008
22,842
I've always thought it would be tacky to have a project with an LED numerical read out and just have it hang out there where you can see the innards and dust can get to it and everything. My personal workmanship is pretty sloppy nowadays, but I do try.
 

Ya’akov

Joined Jan 27, 2019
5,663
I was recently ordered a module that has blue LED displays, it is on a slow boat from China. Thinking of using this to filter the display through. Before I spend any money though, I would like to discuss any other options/ideas members might have? I am always open to new ideas.
I would expect this sheet to be a more appropriate color for a blue LED display. Keep in mind, though, the effect will be to make the display perceptually white behind blue plastic.
 

Thread Starter

Wendy

Joined Mar 24, 2008
22,842
Since they are blue LEDs, I would expect the color to stay blue. Just like red LEDs stay red behind red plastic. The one I was looking at was slightly cheaper.
 

Ya’akov

Joined Jan 27, 2019
5,663
Since they are blue LEDs, I would expect the color to stay blue. Just like red LEDs stay red behind red plastic. The one I was looking at was slightly cheaper.
They will be blue in fact, but they would be perceptually white. That is, to a viewer it will seem like white LEDs behind a blue filter, and if you take a photo the auto white balance will make them white in the photo if they are the brightest thing in the photo.
 

Thread Starter

Wendy

Joined Mar 24, 2008
22,842
They will be blue in fact, but they would be perceptually white. That is, to a viewer it will seem like white LEDs behind a blue filter, and if you take a photo the auto white balance will make them white in the photo if they are the brightest thing in the photo.
I disagree but we shall see.
 

Jon Chandler

Joined Jun 12, 2008
192
I have found clear smoke gray acrylic works great for 7-segment displays of all colors. The gray provides excellent contrast while allowing the color of the LEDs to show through.

For challenging light situations, even direct sunlight, 3M Vikuiti film is stellar. It's kind of like a polarizer, sort of like tiny venetian blind slats embedded in it. Looking at it straight-on, it's the same effect as smoked acrylic. but light coming from off-axis is blocked from hitting the display. Vikuiti film is kind of expensive at nearly $20 a sheet, and may only in available in a box of ten sheets.

Fortunately, a very similar product is available at a much lower price. Computer monitor privacy screens are essentially the same material.
 
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