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The Backlight Page

David Knaack's EL Backlight Page

I did some expirimenting. If you go to a local hardware store such as Ace Hardware, you can get plexiglass. Ask for small scraps and find a piece that will cover the screen nice. You may want them to cut it for you, so you get a good edge.

Use sand paper and sand one or both surfaces. This will reflect the light up as it hits the edges. The mirror needs to be placed on the back of the plexiglass and the plexiglass then against the back of the LCD.

The LCD will be tight, and it may be necesary to NOT TIGHTEN the two LCD screen screws all the way. Remember that the back of the case pushes the screen too. You will also need to remove the foam from the inside of the back cover to make room.

Backlight hardware

As for the LEDs, I used 6 hight brightness Yellow LEDs for mine. The greens might have been better, but they didn't come bright enough. Many LED backlights often are yellow, so maybe the yellow is best. It seems so. I put them in groups of two in parralel, with alternating serial connections like this...

Backlight Schematic

I expirimented with values, but forgot what was best. You could also replace the resistor with a variable resistor to adjust for just slightly dim or totaly dark conditions.

I will also warn again about being careful with those plastic wire ribbons on the LCD. THEY CAN NOT BE FIXED!!! Also, don't crack your LCD. Try to get EXTRA thin plexiglass. 2 mm thickness is about the MAXIMUM!

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