Infrared cameras and IR sensors

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
7 replies · 3K views
fog37
Messages
1,566
Reaction score
108
Hello Forum,

Why are infrared (thermal) cameras, those that produce interesting thermographs of objects, mapping their surface temperature, so expensive?

IR sensors are ubiquitous and very inexpensive...What is the difference?

thanks,
fog37
 
Engineering news on Phys.org
fog37 said:
Hello Forum,

Why are infrared (thermal) cameras, those that produce interesting thermographs of objects, mapping their surface temperature, so expensive?

IR sensors are ubiquitous and very inexpensive...What is the difference?

thanks,
fog37

What IR sensors are ubiquitous and inexpensive? You mean like in a remote control? A camera needs an imaging array with many thousands or millions of IR sensors, not a single cheap sensor. The sensor in an infrared camera is similar to the imaging chip in a cell phone. Semiconductors are very expensive to develop but cheap to manufacture, so they are highly affected by volume. Also, infrared imaging arrays are made for technical reasons out of fancy, expensive materials (not silicon) so that is another reason for their cost.

Digital visible-light cameras used to be incredibly expensive but with volume the cost is very small. If infrared cameras were more popular and they sold in the 10s or 100s of millions believe me they would be very cheap too.
 
  • Like
Likes   Reactions: 1 person
analogdesign said:
What IR sensors are ubiquitous and inexpensive? You mean like in a remote control? A camera needs an imaging array with many thousands or millions of IR sensors, not a single cheap sensor. The sensor in an infrared camera is similar to the imaging chip in a cell phone. Semiconductors are very expensive to develop but cheap to manufacture, so they are highly affected by volume. Also, infrared imaging arrays are made for technical reasons out of fancy, expensive materials (not silicon) so that is another reason for their cost.

Digital visible-light cameras used to be incredibly expensive but with volume the cost is very small. If infrared cameras were more popular and they sold in the 10s or 100s of millions believe me they would be very cheap too.

and on top of all that, there's the electronics and firmware that does the processing of the information from the sensor to produce those interesting thermographs of objects, and mapping of their surface temperature etc

Dave
 
So, in principle, we could build a super-low resolution thermal camera using several infrared sensors, as long as they are sensitive to the infrared wavelengths (I guess around 10 micron) that the human body emits energy at.
 
You need an optical system that works for that wavelength. The infrared sensors in your remote control are big and it would be hard to get an image focused on an array of them.
 
I've also heard that "the lenses are made of Germanium which is more expensive per gram than Gold."