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Messages - dshero

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TFTs / Re: Backlight brightness with TFT displays (5" and 7")
« on: July 20, 2015, 10:48:39 AM »
Thanks for answering my 4th question. Can you please address the first 3 questions I had? Namely, why does the 5" backlight need more power than the 7" display backlight, which results in twice the brightness for the 5" display? And why does the 5" display need twice the brightness? If I go with the 5" display, can I reduce the current to the backlight and still get good results, or if I go with the 7" display, will it be bright enough with the specified backlight current?

TFTs / Backlight brightness with TFT displays (5" and 7")
« on: July 17, 2015, 10:31:52 AM »
I plan to design in a TFT display of yours into equipment that our company manufactures. I am looking at the following possible displays:
According to the backlight specs, the 5.0 needs 60 ma@19.2V yielding 400 cd/m^2 luminosity. The 7.0(L) needs 60 ma@16V yielding 160 cd/m^2, and the 7.0(V) needs 60 ma@16V yielding 220 cd/m^2. I have the following questions:
1) Why does the 5" display need more backlight power than the 7" displays?
2) The higher backlight power appears to produce about twice the brightness on the 5" than what is produced on the 7" displays. Does this mean the 5" is going to appear overly bright or the 7" displays dim?
3) I am a little concerned with power consumption, so am wondering if I go with the 5" display, can I reduce the backlight current and still get good results?
4) Our equipment (runs 24/7) has a life > 10 years. Since the backlight has a decent, but shorter life of maybe around 20,000+ hrs, we will need to increase the backlight life. We plan to do this by reducing the backlight power when the display is not being looked at (most of the time). We would like to reduce the backlight current to maybe 10% instead of turning it all of the way off so that the display is still partially viewable instead of totally off. I assume that this should greatly increase the life of the backlight, is this a correct assumption, or will we need to totally turn off the current to the backlight to increase its life?

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