Originally Posted by HardCaliber
I was wondering the same thing about the bulb life-span. Sony is promoting it was having a long-life, but isn't this unproven tech? It's a "hot" bulb and heat is often a cause of things wearing out over time.
I'm just curious because the Bravia VE5 is way up on my short list of what to buy soon. I saw a demo unit at BB yesterday and I thought it was a stunning picture. The best my admittedly untrained eye has seen.
After investigating a bit about the bulbs, it seems that the terms are pretty misleading. From what I've read, hot cathodes are filled with low-pressure gas and heated by the Tungsten coil (which releases electrons to light the bulb). It is not the gas that runs out, but traditionally the Tungsten filament that breaks after being worn down by its own heat.
New hot cathode filaments are actually covered, rather than bare (and are also often removed from direct interaction with the gas), reducing the amount of energy needed to heat the gas and emit light. Since they are covered, the disintegration of the Tungsten is also lessened.
A cold cathode is coated on its interior with material that can create electrons by being struck with fast-moving ions, lighting the bulb. Yet, to do this requires a large amount of voltage and although the initial energy used does not heat the cathode (thus, cold cathode), sustained lighting creates a large amount of heat.
This is speculation, but if Sony's smaller hot cathode is designed as an indirect, covered filament, it should have a long lifetime.