Guest Post: Eric Seigler, Nanolumens
When working with any sort of light-producing electrical product, be it a laptop, a desk lamp, or a commercial digital display, you need to be mindful of the product’s heat output.
If you’ve felt the warmth of a computer on your lap or the heat of an older lamp bulb, you’re already familiar with the fact that not all the energy that goes into these devices comes out in the form of light – some of it is lost to heat.
The amount of energy these products lose to heat is a function of their energy-efficiency. A perfectly efficient bulb or diode would convert 100% of its electrical energy to light for example, while a perfectly inefficient product would convert 0%. Large-format LED displays typically fall somewhere in the middle.
Though LED displays are the brightest commercial digital display solution on the market, these displays produce heat in just about every part of their design; at the diode level, at the driver chip level, at the power source, through the circuitry, everywhere.
This heat output is measured in British Thermal Units, or BTUs. One BTU is equal to the amount of heat needed to heat one pound of water by one degree Fahrenheit. This is equivalent to roughly 1,055 joules.
“But the BTUs!”
In order to reduce the amount of heat their diodes are subjected to, some manufactures install the power sources for their displays in a location separate from the display itself. That keeps the heat generated by those power sources away from the diodes, ostensibly to protect the diodes from any sort of performance degradation or lifespan erosion that may result from exposure to consistently higher levels of heat.
Diodes operate best in cool conditions; as their surrounding temperature rises, the accuracy of their colors can shift, their fail rate can increase, and their lifespan can shorten. Or at least, that’s the case in extreme conditions.
Diodes within a well-integrated display will never encounter the sorts of temperatures that will cause noticeable compromises in their performance or lifespan, and most integrators will incorporate air conditioning to keep the entire system cool anyway.
Though these manufacturers advertise that keeping the display power source separate is imperative to protect their diodes from the power source’s heat output, this policy is just a remnant of their prior work with LCD displays.
And even then, it had nothing to do with heat output!
LCD manufacturers incorporated remote power sourcing to make maintenance on these power sources easier to perform. If the power source was mounted next to the LCD display, technicians would have to remove an entire LCD panel just to get to it. Moving the power source elsewhere cut out this labor and this display downtime.
When these LCD manufacturers transitioned to the LED world, they kept up the habit, though there was really no need: LED boards can in most cases be popped on and off painlessly for internal maintenance, because they are designed to be front-serviceable.
So if a manufacturer tells you that you’ve got to have remote power sourcing for your LED display because otherwise the heat output will cause issues, don’t believe the company. There is no need for that extra legwork, and it’ll only create further complications.
Using remote power is a remnant of older technology and has no bearing on how LED displays currently work. Your diodes will be just fine if you mount your power sourcing the normal way.