Hmmm... problem with my E30bx?

[cvanc]

From the "Is this normal" department...

Roughly every 20 seconds the screen freezes and I hear a soft click.  It seems to do this all the time.

Normal?  Thanks.

[Fraser]

Welcome to the world of microbolometer based thermal cameras 

Yes this is normal. The microbolometer based cameras carry out what is called Flat Field Correction (FFC) using a 'flag' that is introduced into the optical path. The flag is at a known temperature and is 'flat' in terms of Delta T. The camera uses these facts to compensate for any individual drift in the output of the microbolometer pixels over time. When a thermal camera is first started, it is not unusual for there to be quite regular FFC events. After a settling time, the period between FFC events usually extends to around 120 seconds. The click you hear is the solenoid operating the flag and the frozen screen is the last image collected from the microbolometer before the flag was activated. The FFC event is usually quite short and you learn to accept it as just a part of the cameras 'needs' in order to operate. Some cameras do not use an FFC flag and rely on other methods to tame the drift in the microbolometer pixel outputs. But that is another story for another day 

Fraser

[Fraser]

If you want to see the inside of a typical modern microbolometer camera, take a look at this thread:

https://www.eevblog.com/forum/thermal-imaging/thermal-camera-teardown-the-flir-tau-320-by-fraser/

I attach an image of the FFC shutter in front of a microbolometer

Fraser

[cvanc]

Welcome to the world of microbolometer based thermal cameras 

Yes this is normal.

Alrighty then.  I'll worry if it stops doing it 

[nidlaX]

Welcome to the world of microbolometer based thermal cameras 

Yes this is normal.

Alrighty then.  I'll worry if it stops doing it 

Indeed, it's a common fault in microbolometer modules of all kinds to have the FFC shutter mechanism fail for whatever reason.

[cvanc]

I actually used the camera for a project yesterday and it was powered on for a couple hours.  I can verify the shutter cycling happens less and less frequently as the camera warms up (or cools down?  Is there a Peltier in there?).

When first turned on the shutter cycles roughly twice every minute; once it's been on for a while it slows way down to once every few minutes (I didn't bother to time the exact interval).

Thanks all for the input and assistance.

[Fraser]

Cvanc,

IIRC the Exx series uses a temperature stabilised microbolometer, the Ex series do not have temperature stabilisation. The Exx operates in an active die temperature stabilisation mode, whereas the Ex operates in a passive die temperature compensation mode. Two very different approaches.

Temperature stabilisation usually takes the form of either heater or a Peltier TEC. The Peltier TEC  is common in high performance Microbolometers and enables the OEM to squeeze maximum performance out of the sensor thanks to its die temperature stability. The down sides are the current consumption of the Peltier element when working hard, and also potential vacuum contamination over time via outgassing from the integrated Peltier element within the vacuum chamber.

The microbolometer is 'uncooled' and is actually operated at around +32C. This temperature is achieved via a heater, Peltier Element or natural thermal equilibrium within the die that incorporates the ROIC (as occurs in the Ex series microbolometer).

Fraser