DIY Ledpanel lights from old TVs, discuss.

[Björn Benckert]

Bumped into some videos about this on youtube and decided to run by the recycling place close to where I live and snatch a few old screens and test. Have only fiddled with one old computerscreen so far but I really like the light it produce. Its very straight, has a long falloff and the nicest of soft shadows stuff looks like good 3d renders when using a large plane as lamp.

In short: You can rip apart any led tv, remove the front lcd element. Behind it there is a stack of diffusers and the backlight element that works as a 90 deg spread for the light that comes from a led strip sitting on the side.

The whole thing can usually be powerd with 12 volts and has a 5v ”on” cable and a 2.5-5v dimmer cable.

Possibly not the strongest of film light panels, but imagine making one of a qled 75” or such. Or replacing the tv led strip with somthing stronger. The backlights in these kind of screens are pretty hightech optics, if they where developed for the film industry Im sure they would cost a few fortunes each but as its old household stuff its simply possible to fetch at the junkyard.

Anyone else been testing this, old tv led panels used as light source?
Anyone know a good really strong led strip that can be used together with LG back light elements?


The led element removed.

led tv backlight by Björn Benckert, on Flickr


mixed light, but still look at the shadows...

led tv backlight by Björn Benckert, on Flickr

led tv backlight by Björn Benckert, on Flickr

led tv backlight by Björn Benckert, on Flickr


led tv backlight by Björn Benckert, on Flickr


Really directional output so from an angle there is hardly any light.
led tv backlight by Björn Benckert, on Flickr

 

[Karim D. Ghantous]

This is genius. Why didn't I think of this? I have access to disused LCDs so I will give it a try.

 

[Blair S. Paulsen]

Now, let's mix in an app that puts a test pattern on the screen that you snap with your smartphone. This "profile" is used to create an inverse LUT to null out the various biases of used LCD panels. In addition to neutralizing white output, the inverse pre-LUT (I prefer the term dynamic compliance) should also significantly improve the accuracy of whatever color one might select...

Cheers - #19

 

[Kwan Khan]

Done this long ago...
This new video will help... Enjoy

 

[Björn Benckert]

Now, let's mix in an app that puts a test pattern on the screen that you snap with your smartphone. This "profile" is used to create an inverse LUT to null out the various biases of used LCD panels. In addition to neutralizing white output, the inverse pre-LUT (I prefer the term dynamic compliance) should also significantly improve the accuracy of whatever color one might select...

Cheers - #19

As I understand most of they are seriously white. ie. K5600 as they got plenty of difficulty to calibrate the actual LCD element so the manufacturers make sure to try to make the backlight as clean and flat as possible. And you cant put a pattern on the screen as the screen element that makes up graphics is removed. Basically its just what lights up the graphics thats in use. A LCD TV in its normal state does not give much light. But when you remove the LCD which is like a black hardly possible to see through glass... whats behind there shine quite a bit of light and a very evenly, like more evenly than the most expansive led fixtures I seen.

The thing is there is so many old screens being tossed away. At the recycle center where I went they had two containers filled... Imagine just how many good quality 12V led strips are being trashed.

 

[William Long]

This is brillant! I'm off to the tip! )

 

[Björn Benckert]

This is brillant! I'm off to the tip! )

Love to see. So post your findings. Im too deep under the snow at the moment so dont have the time. But would love to see a face lit by something like a 65” display and shot with a proper red cam. I can only think the result would be smashing.

 

[Blair S. Paulsen]

Absolutely love this kind of up-cycling. Thanks for clarifying that the screen mask is removed. Perhaps the easy way to get a handle on actual output characteristics is to aim the source at a known reflective surface like an accurate gray or white card (be aware that most white paper is bleached and reads blue). Capture that with your camera and analyze the result. If, as Björn suggests, the output from the LED edge lights is 5600K with minimal tint - even better!

Cheers - #19

 

[Björn Benckert]

Absolutely love this kind of up-cycling. Thanks for clarifying that the screen mask is removed. Perhaps the easy way to get a handle on actual output characteristics is to aim the source at a known reflective surface like an accurate gray or white card (be aware that most white paper is bleached and reads blue). Capture that with your camera and analyze the result. If, as Björn suggests, the output from the LED edge lights is 5600K with minimal tint - even better!

Cheers - #19

Yes, you could just aim camera straight at it expose it lit at mid gray and color pick it in rcxp to see temp. And normally they also come with a stack of color and diffusion filters which can be removed and or also easy enough to put any kind of gel in that stack.

 

[Jeffery Anderson]

did you build a row of LED strips in the back or just place them around the edges?
(as seen in the video, they are just on the edges)

 

[Björn Benckert]

did you build a row of LED strips in the back or just place them around the edges?
(as seen in the video, they are just on the edges)

When you rip of the led pannel of a led TV there is a few sheets of diffusers. And then there is the backlight panel. Basically a plastic sheet that is hit with light normally from one side and it distribute the led strip light evenly over the whole panel. So no real need to add led stripes the one sitting in the screen is enough as it is.

 

[Jeffery Anderson]

When you rip of the led pannel of a led TV there is a few sheets of diffusers. And then there is the backlight panel. Basically a plastic sheet that is hit with light normally from one side and it distribute the led strip light evenly over the whole panel. So no real need to add led stripes the one sitting in the screen is enough as it is.

the video tells you to add LED strips(95+CRI), to get the correct color temp, which would be 5600K

in the video, he places the strips around the outside, so they face inward, not filling the back of the panel with strips

I just wondered if someone made one with stips on the back and sides to get for power output/Lumens from the lamp and if that had any drawbacks.