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Life span of backlight on Parallax LCD? — Parallax Forums

Life span of backlight on Parallax LCD?

T ChapT Chap Posts: 4,223
edited 2008-11-20 17:39 in General Discussion
Should some effort go into conserving the backlight on the 2 x 16 LCD?

I am wanting 10+ years on the unit. It is possible to have it light up on any button activity, then go out after a while, but would prefer to let it stay lit for the life of the product.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-11-19 19:29
    Hello,

    The backlight is LED-based so it should have a very long lifetime. If you would like to only have the backlight come on at button press and timeout and turn off after activity that can be done too. In fact I have done this in a few projects. One other idea is one I used in my Digital Thermostat. If your project has a clock in it (such as DS1302) you could set it to only come on when it is normally dark. Ideally, if you want it on when it’s dark you could use a photocell to detect the light level and turn it on/off at appropriate levels. If you do this you will still want to add some delay on the toggle so people passing in front of the sensor don’t have it turning on/off. Take care.

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    Chris Savage
    Parallax Engineering
  • T ChapT Chap Posts: 4,223
    edited 2008-11-19 19:56
    Great, I didn't know it was LED based, maybe just leave it on then.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-11-19 20:04
    EL backlights (and even CCFL) require inverters to handle the require high voltage. Using the LED backlights keeps cost down and lifetime up, since the LED backlights wil outlast the EL or CCFL units.

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    Chris Savage
    Parallax Engineering
  • MinimumWageMinimumWage Posts: 72
    edited 2008-11-19 21:48
    Chris,

    On a related note - does the backlight eventually turn off if not "refreshed" by a software command to keep it on? I have one project with a 2x16 LCD running 24/7 and I noticed that the backlight eventually turns off, although the time period must be many hours (or days? - I've never been able to catch exactly how long.)

    Mike
  • $WMc%$WMc% Posts: 1,884
    edited 2008-11-20 01:20
    Hello All

    I have had this " ? " for A while about the "backlite"...I'm happy to here Its LED based. I have always truned the backlite on w/ any key press and then "time out" the backlite if no keys pressed for fear of burning out the backlite.....I feel better now that I've read this post about the backlite....Thanks for the Info Mr.Savage............

    ___________________________$WMc%_____________________
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-11-20 16:28
    Mike,

    No, there is no timeout on our displays…some displays, such as the Matrix Orbital units have a timeout that is user definable. I wonder if you’re having a code or hardware issue which is causing the problem.

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    Chris Savage
    Parallax Engineering
  • MinimumWageMinimumWage Posts: 72
    edited 2008-11-20 17:39
    Chris,

    Thanks for the update, I was just curious. I'll have to check into the cause further at some point. I can probably just add a command to turn the LCD on somewhere in the main code loop instead of just in the display initialization section. Truthfully it's never been enough of an issue to pull the assembly out of the system and troubleshoot it. The LCD is still perfectly readable without the backlight.

    Mike
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