# Infrared cameras and IR sensors

1. Aug 19, 2014

### fog37

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

2. Aug 20, 2014

### analogdesign

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.

3. Aug 20, 2014

### davenn

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

4. Aug 20, 2014

### fog37

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.

5. Aug 20, 2014

### Okefenokee

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.

6. Aug 20, 2014

### Pseudo Zing

I've also heard that "the lenses are made of Germanium which is more expensive per gram than Gold."

7. Aug 20, 2014

### AlephZero

It's true that IR lenses can be made from germanium, but the current price of Ge is less than $2 per gram, compared with over$40 per gram for gold.

8. Aug 20, 2014

### Baluncore

During the last few weeks this thermal camera for the iPhone 5/5S has become available.
Resolution is 80 x 60 pixels.
Price is between US$450 and US$550 on eBay.
http://www.flir.com/flirone/