Electronics > Projects, Designs, and Technical Stuff
Adding CCFL light or LED backlight to a 6 digit/7 segment LCD display
hafrse:
Hello,
Is possible to add CCFL light or LED backlight to a 6 digit/7 segment LCD display which has no backligt from the beginning? I have seen some article about doing that many years ago (could not find now...) by removing the reflective shield layer from the backside , not sure if I should seprate that shield from a possible layer (polirization ?) between it and the LCD glas or other consideration that I should be aware off.
ATtached 2 images from the LCD display
Mnay thanks in advance!.
SeanB:
How about adding side illumination to the edges of the display instead. Not as even, but will work well enough for most applications, using only 2 thin SMD led chips per side. You can get the chips new, as modules you place next to the display, or grab them off an old flat screen LED backlit display easy enough, though often those are a multichip module per pack, often having around 9V forward drop, but really bright at 20mA. done that a few times to a LCD display to make it night readable, not even, but better than nothing, and pretty much the common method for these displays.
james_s:
It really depends on the display and whether there's room. Also it's difficult to get a nice smooth illumination, EL strip does work well though if you have space and power budget for the inverter.
Buriedcode:
You would probably have to remove the reflective coating on the back, which isn't easy as it'll be bonded well. Then you could use an off-the-shelf backlight panel (light pipe) for character LCD's. Example:
https://shop.pimoroni.com/products/white-led-backlight-module?variant=36999548170
https://www.aliexpress.com/w/wholesale-led-backlight-panel.html
I believe the polarizer is layers are on the front of the display, but there could be one on the back.
The downside of converting a reflective display to one with a backlight is, the contrast takes a hit when the backlight isn't on. Many displays are "transflective" which is a combination of the two - a partially reflective coating that allows some light through for the backlight. Your display *might* have that, but it is easily checked - if it lets any light through the back. EL strips are great if you have limited space (<2mm) but a hassle to drive when compared to a single LED lightpipe.
james_s:
On many displays the reflective coating is just a sticker that peels off easily, I helped a friend add a backlight to some GameBoys a while back. I suppose it could vary widely though.
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