new kind of clocks?

[Kasper]

anyone seen this
http://www.ebay.com/itm/260601924906?ss ... 1438.l2649

would this be possible to make into a watch?

can someone explain? is this a new kind or something old?

[abem]

This is something from the 1970s and earlier. It uses a vacuum fluorescent display which you may remember from the hand held video games of the late 70s and early 80s (if you are a certain age):
http://en.wikipedia.org/wiki/Vacuum_fluorescent_display

The only problem is that VFDs use a lot of voltage - 9 to 15 volts. I'm not an electrical engineer but I have never seen one used in a watch or other small portable device, so I'm guessing that the power consumption and voltage are prohibitive (although given a large enough watch it would work as in the nixie watch). Perhaps someone here with a background in rustling electrons can give a better answer.

Neat clock display, though. There certainly could be watches with such neat and colorful displays although they would probably have to use OLEDs or backlit LCDs. They haven't materialized, not for technical reasons but since nobody thinks there is a market.

-abe.

[Kasper]

thanks Abe for the neat explanation...i forgot about wiki.

Early on, the main disadvantage of such displays was their use of significantly more power (0.2 watts) than a simple LCD

now i was wondering how much watts does a led watch needs when pushing a button ?
i cannot find anything about it in wiki about leds.

[rewolf]

now i was wondering how much watts does a led watch needs when pushing a button ?

50-100mW (0.05-0.1W)

That VFD could be put into a watch, but it has some disadvantages:
a) very large: "VFD size is 50x68x9mm" + electronic + battery + housing
b) power consumption - VFD is nothing but a flat vacuum "tube" with all its well-known disadvantages.
The one in question requires:
- Filament heating 2.4Volt AC, 453mA, that is 1.1Watts for "heating" alone, yet nothing displayed.
- Grid/anode voltage 30V, ~1mA per lit segment, that is another 0.5W for 15 segments lit.
All in all the display alone takes 1.6W, that is, from a 3V Lithium "photo" battery (like CR123A or CR2) it would draw around 0.6A and drain this battery within an hour or two