Thinkpads Forum

In my laptop, I've set the lcd to turn off after 15 min of inactivty. If the LCD repeatedly gets turned on/off because of it in a day, is it bad for it ?

No, it won't hurt it.

I'm of a different opinion.... Since the CCFL is a fluorescent lamp I would assume it will be affected like its bigger cousins:

http://members.misty.com/don/f-lamp.html
http://www.eere.energy.gov/consumer/you ... opic=12280
http://www.lightingdesignlab.com/articl ... escent.htm
http://www.consumerenergycenter.org/myt ... ights.html
http://www.newton.dep.anl.gov/askasci/e ... g99369.htm

(Googled "fluorescent lamp frequent on off")

While the general consensus is that it's hard to say whether or not it's more energy efficient to leave a FL on for some indeterminate time vs. turning them off, frequent on-off cycles does appear to lessen the life. Going to the other extreme, I would also not leave the lamp on 24/7. Having the CCFL shut off after 15 minutes and then waking up the system right away may not be good for the lamp. However, you probably don't do that too much. I'd assume that the laptop shuts off the display and maybe you don't get back to it for a few hours, so it's really not being turned off and on every 15 minutes.

rkawakami wrote:I'm of a different opinion.... Since the CCFL is a fluorescent lamp I would assume it will be affected like its bigger cousins:

http://members.misty.com/don/f-lamp.html
http://www.eere.energy.gov/consumer/you ... opic=12280
http://www.lightingdesignlab.com/articl ... escent.htm
http://www.consumerenergycenter.org/myt ... ights.html
http://www.newton.dep.anl.gov/askasci/e ... g99369.htm

(Googled "fluorescent lamp frequent on off")

While the general consensus is that it's hard to say whether or not it's more energy efficient to leave a FL on for some indeterminate time vs. turning them off, frequent on-off cycles does appear to lessen the life. Going to the other extreme, I would also not leave the lamp on 24/7. Having the CCFL shut off after 15 minutes and then waking up the system right away may not be good for the lamp. However, you probably don't do that too much. I'd assume that the laptop shuts off the display and maybe you don't get back to it for a few hours, so it's really not being turned off and on every 15 minutes.

Don't worry about your LCD lamp. Turn it off as much as you need. Modern LCD lamps are controlled by sophisticated electronics (which resides in the inverter board). To start the lamp you need to ionize the inner gas. In old lamps an inductor and bimetall is used to induce a shock ionization. Not good, because of wear and tear of the electrodes. That's why old lamps in supermarkets sometimes flicker (they are dying). LCD lamps use radioactive substances to pre-ionize the gas. Don't worry about on/off cycles. In fact, once the gas is ionized you can use the lamps as stroboskopes (have a look at some discotheques).
Your main worry is the coating of the lamp. The 3 differents coatings decay differently and your lamp will experience different temperature induced color variations, such as reddish and yellowish colors. Your lamp usually will become useless with wrong color temperature, before the electrodes might wear out. Besides, a new lamp costs only $20,-
which is peanuts...

If you worry about turning it on and off frequently, why not dim it down instead. I do that whenever I am away for longer than a few minutes.