IRISS VPFR Infrared Window

HOW CAN MY INFRARED CAMERA SEE THROUGH A GRILL?
Upon first inspection of the VPFR infrared window I asked myself this same question that everyone else does. How am I going to get a clear Infrared image with a grill in the way? The manufactures states that an infrared camera will focus past the grill, I was a little sceptical at first but found that an IR camera will indeed focus past the reinforced grill.

The only issue that I found with the grill was that some cameras that were fitted with a wide angle lens had trouble totally focusing past the grill. This is commonly referred to as a “ghosting” effect. This “ghosting” effect became more prevalent when manipulating the camera on an angle to increase the field of view (FOV). I found this to be a non issue when using a standard 24° lens or a telephoto lens.

DURABILITY
I was most impressed with the certifications that the VPFR range of windows meets. This is truly an industrial grade infrared window meeting UL 50V, IEEE C37 20.2.a.3.6: Impact and load, UL 746C: Impact and flammability, UL 508A; ANSI UL 508A, IP65 / NEMA 4 and Lloyds of London Type Approval. There is no crystal window in the world that can match the VPFR for durability.

The fact that IRISS offers an unconditional lifetime warranty is testament to the durability of the product and offers piece of mind when considering the purchase of infrared windows.

POYLMER vs. CRYSTAL – TRANSMISSION RATES

IRISS Infrared Window

The argument of polymer vs. Crystal windows is something that continues to rage on. The main augments are with the grill, the fact that you cannot do a visual inspection through the VPFR polymer window and the transmission rates.

First of all after using the VPFR series infrared windows on many types of cameras and lens sizes I found that the only time a “ghosting” effect was present was with a few wind angle lenses, everything else focuses right past the grill like it is not even there.

The advantage that a crystal window has over polymer is that you can perform a visual inspection as well as an IR inspection. This is something that manufactures of crystal windows promote. But how much are you really going to see through a 2, 3 or 4 inch hole in a dark cabinet? Infrared windows are not really designed for visual inspection but crystal does have that marketing advantage.

When performing an IR inspection through an optic the most important thing is knowing the transmission rate. IRISS offer a lifetime guarantee against transmission drift with the VPFR range. If there was one reason that you would by the polymer window over crystal is this reason.

Crystal may be able to offer transmission rates of up to 98% but this is in the shortwave of the spectrum. How many people are using shortwave? In the long wave the transmission rate of the polymer which is between 50-60%. Once you reach the long wave of the spectrum the transmission of crystal falls away sharply after 9?m making the information quite misleading. IR polymer can be used from 0.15-22?m where as crystal (CaF2) is good from 0.13-10?m.

Crystal (CaF2) is a material that deteriorates over time. What is the point of doing an IR inspection through an optic if you don’t have a fixed transmission rate? There is no possible way you could collect accurate data. At the end of the day predictive maintenance is about recording accurate data consistently and the VPFR polymer windows provide this.

CONCLUSION:
The VPFR range of infrared inspection window from IRISS is a very realistic alternative to crystal. The clear advantages are; It is the worlds only industrial grade infrared window that meets higher standards than crystal windows, is cheaper than crystal and has a fixed transmission rate. Even though a visual inspection is not possible through a polymer optic having a fixed rate of transmission is the only way to accurately collect data, something that NO crystal window can offer.