Interesting opto device

[MarkAren]

Hi All,

An interesting item you may be able to help me identify.

http://www.geocities.com/markaren10/misc/opto1.jpg

14mm dia, 7mm high, 6 leads, clear lid, writing on the side "12188",
no manufacturers mark, logo or name.

The device is three layers;
- Pelitier device, pins 1 & 2 (bottom)
- Thermistor, pins 4 & 5
- Opto device, pins 3 & 6 (top)

Measure resistance between 4 & 5 (nominally 10k). Apply 500mA between
1 & 2. Resistance goes up or down depending upon direction of current.
So there is a method to temperature control the opto device. The whole
unit was mounted on a heatsink.

Opto device: 500k nominal resistance, changes to 400k with a very
bright light. It might be IR sensitive (?) Does not appear to generate
any voltage and have the same resistance either way around so
apparently not a semiconductor.

I assume that the opto device is cooled by the Peltier device (and
hence the need for the external heatsink).

Anyone seen anything like this before ?

Regards,

Mark

 

[K Ludger]

Hi All,

An interesting item you may be able to help me identify.

http://www.geocities.com/markaren10/misc/opto1.jpg

14mm dia, 7mm high, 6 leads, clear lid, writing on the side "12188",
no manufacturers mark, logo or name.

The device is three layers;
- Pelitier device, pins 1 & 2 (bottom)
- Thermistor, pins 4 & 5
- Opto device, pins 3 & 6 (top)

Measure resistance between 4 & 5 (nominally 10k). Apply 500mA between
1 & 2. Resistance goes up or down depending upon direction of current.
So there is a method to temperature control the opto device. The whole
unit was mounted on a heatsink.

Opto device: 500k nominal resistance, changes to 400k with a very
bright light. It might be IR sensitive (?) Does not appear to generate
any voltage and have the same resistance either way around so
apparently not a semiconductor.

I assume that the opto device is cooled by the Peltier device (and
hence the need for the external heatsink).

Anyone seen anything like this before ?

Regards,

Mark

Maybe its a Laser Diode (or high pwr LED?), thermistor for temp measurement
feedback, peltier to manage temp. Where did you find it?

 

[Michael Brown]

Hi All,

An interesting item you may be able to help me identify.

http://www.geocities.com/markaren10/misc/opto1.jpg

14mm dia, 7mm high, 6 leads, clear lid, writing on the side "12188",
no manufacturers mark, logo or name.

The device is three layers;
- Pelitier device, pins 1 & 2 (bottom)
- Thermistor, pins 4 & 5
- Opto device, pins 3 & 6 (top)

[...]
Maybe a long-wavelength (thermal) IR detector. One of those lead
titanate things or something. Out of an old Sidewinder maybe?

Yup, my money would be on an IR detector as well - lead selenide (PbSe) or
lead sulfide (PbS) is what you're thinking of, I think Both are
frequently used with cooling, and need monitoring of the temperature since
their peak sensitivity depends on temperature. Exactly what it's from is
difficult to say, since they're used all over the place, and 12188 doesn't
seem to give any useful hits.

 

[Nemo]

An interesting item you may be able to help me identify.

http://www.geocities.com/markaren10/misc/opto1.jpg ....
The device is three layers;
- Pelitier device, pins 1 & 2 (bottom)
- Thermistor, pins 4 & 5
- Opto device, pins 3 & 6 (top)

I suggest a germanium or GaInAs avalanche photodiode for ultrasensitive
infrared detection (astronomy, microanalysis etc - but lately the hot
market is single photon detection down optical fibres for quantum
encryption). Normally used cooled - sometimes with liquid N2 - have a
look at the J16TE series of widgets from Judson Technologies:

http://www.judsontechnologies.com/germanium.htm

These have an integrated TE cooler too. What I think you have is a
prototype version of one of their things, or a one-off remarkably like
it made by some researcher in a lab (there are various mad scientists
locked up in labs around the planet trying to improve the materials used
in these photodiodes for their PhD's).

Having identified the device, we need to apply Rule 34* to find out what
it's REALLY used for.

 

[Michael Brown]

I suggest a germanium or GaInAs avalanche photodiode

Unlikely ... looks nothing like the ones I've used. Both the connections to
the active part appear to be on the same side (left-right as opposed to
front-rear). Also, the facing surface is non-uniform. Since avalanche
photodiodes are usually made by evaporating some conductor onto the wafer
the front surface should be near mirror-like unless it has been damaged
through sparking. Finally, the OP said that it appears to be unpolarized and
non-photovoltaic, which doesn't really sound like a photodiode