The Breitling Watch Source Forums

I've been digging around to see how temperature compensation works in quartz movements. I figured I'd open it up to the forum and see if there is somebody who can help.

There are a series of patents available. Here are just a few:

http://www.freepatentsonline.com/3792377.pdf

http://www.freepatentsonline.com/4321698.pdf

Most of the patents are from the 70's and 80's and, as you know if you are familiar with patents, they are purposefully written as cryptically as possible.

My question is if anyone has an explanation of how modern companies, like Breitling, accomplish temperature compensation for their ultra-precise quartz movements. Any and all input is welcome. If I find anything that's more useful, I'll post it right here too!

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“The only reason for time is so that everything doesn't happen at once.” - Albert Einstein

OK, here goes.........

A quartz watch works by measuring the frequency with which the crystal vibrates when subjected to electric current. The crystal generally vibrates at 32,768Hz (although other frequencies are available) and the watch will therefore tick once for every 32,768 vibration cycles.

However, the rate of vibration is affected by temperature, and generally crystals are only going to be accurate at around 27 celsius. The rate of variation isn't much, but it adds up! The good news is that the variance can be predicted - i.e. the variance can be calculated based on the actual temperature.

Breitling's SuperQuartz, and virtually all other modern compensated quartz technologies are thermo-compensated. This involves a temperature sensor and some funky computing to adjust the rate at which the watch ticks.

For example, if the temperature is a constant 20 celsius then the computer chip can look up the rate at which the quartz slows down with a drop of 7 degrees and make the watch tick more frequently than every 32,768 cycles to compensate for the slower vibrations and prevent the watch from losing time.

In the real world only one tiny adjustment is necessary every few minutes.

So comprehensive, it's worth reading twice! (Dial-up playing up again, Roff? )

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Driver8

Site Moderator

Oops, now corrected.

I actually posted it three times and only deleted one

I'm blaming admin for this one - hit submit and nothing happened!

Thanks Roff.

Interesting. Essentially it's a "look-up" table to account for known variation at various temperatures. Not too complicated but clearly effective. This is the gist of what it's the literature but I wasn't sure of there was some more elaborate method currently employed.

I had thoughts of Peltier cells being used to regulate the quartz temperature to maintain the 32 kHz. I suppose this would be more "correction" than "compensation". Goes to show you that the simplest answer is usually the best one.

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“The only reason for time is so that everything doesn't happen at once.” - Albert Einstein

A while ago I stumbled across this very lengthy article on thermocompensation techniques on another forum...I still have yet to read all the way through it, but it's very interesting: http://forums.watchuseek.com/showthread.php?t=2087.

In fact, it's pretty much a compendium of everything you ever wanted to know about the quartz movement.

According to the article, the Breitling superquartz movements use the same technique as the ETA thermoline line, which is "digital count adjustment" where a thermistor is used to measure temperature and adjust for the thermal variation of the quartz vibration. There are other methods, though, that attempt to control the actual vibration of the crystal itself and make it less sensitive to temperature.

Another fascinating tidbit: Both Omega and Citizen produced watches over 30 years ago that rivaled and beat (respectively) modern thermocompensated movements. These were "megaquartz" models that used specially cut super-high-quality quartz crystals that vibrated between 2.4 and 4 MHz (as opposed to the 32kHz of a normal quartz movement).

The problem is that the Omega cost $2000 and the Citizen cost $15,000 in 1970 dollars. The Omega was accurate to 12 seconds per year and the Citizen to 3 seconds per year. The difference in accuracy between the Omega and the Citizen was kind of a moot point, IMHO, because both required yearly battery changes.

///M

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There is a very fine line between "hobby" and "mental illness." --Dave Barry

Of course they do...they are thermolines

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-RJ

Yes, I know that, but not everyone reading my post necessarily does.

///M

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There is a very fine line between "hobby" and "mental illness." --Dave Barry

You do know that if you lose 3 or 12 seconds per year, that is spread over the entire year and not just on the final (=battery change time) day?

Just joking - very interesting find. I enjoyed to read the post.

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Collection: http://s540.photobucket.com/albums/gg32 ... mview=grid

Thanks for the link Mofongo, massive that it is I'll take the time to get through it one of these days

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Happines is Good Health and a Bad Memory.
"Ingrid Bergman"

Wait Citizen make good watches????

I was always told they are expensive for what they were (and i regularly see them in the $300-$600 price range)...

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Yes citizen MADE one of the expensive watches at that time "Which is the Citizen megaquartz "2,500,000" million yen in the 1970's. along with with omega but their inventions did not last long because the general public cannot afford to pay for it. Although the crystals they used were unique and rare at that time. That is where revolution came in and now we all have sapphire crystals if not most of it on our watches.