How does the Indiglo nite-lite in my watch work? I’d guess it’s the same princple as the backlight on a Palm Pilot or a laptop, but I don’t know how those work either.
Indiglo watches utilize what is known as an Electro Luminescent Panel to provide the backlighting for nighttime viewing.
Without getting into the physics of the matter:
When AC is applied to two electrodes to the thin panel, a visible glow is produced. The normal range of voltages required to produce light is on the order of 90 to 300 volts.
The frequency (roughly the number of times per second that the signal changes polarity)of operation is often higher than the 60Hz (1Hz = 1 Cycle Per Second)of the AC that we use to power things like lights, toasters, etc. 2Khz to 20KHz is not uncommon.
Not all notebooks or palmtops utilize ELP technology for backlighting purposes, but I have seen some that do, so your evaluation of the sinilarity of the technology employed may indeed be correct.
For those devices that do use ELPs, the voltage necessary for ELP operation is generated by a circuit module known as an inverter. It’s the job of the inverter to convert the DC voltages of the battery to an AC waveform of the correct voltage and frequency.
ELPs can be manufactured on a rigid ceramic substrate (base or foundation) or can be fabricated using flexible materials (polymers and metalized coatings). The latter are currently more common.
Common ¢ for all ages…
“Well, there was that thing with the Cheese-Wiz…but I’m feeling much better now!” – John Astin, Night Court