Products > Thermal Imaging

what surface do you use for evaluating lights?

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coppercone2:
they do say something about PWM IR being visible at 1/2 the frequency, i.e. 1000nm = green.

could I have seen a PWM IR led at 830nm that look like 415 or something like that? maybe 50% duty cycle PWM if that is true about the eye seeing blinky ir

Been meaning to try that. it would require ssome advanced technology like AC wave forms and pressing buttons

i knew it was a good idea to take this twisted pair of wire and put it in a wire storage box with zip ties instead of throwing the 2 foot segment away. now i might try this..just solder it on and plug into audio amp.i think i can do it

coppercone2:
hmm I plugged it into a hp DC power amp and while it blinks at 1hz if I set it up high to like 200Hz or KHz it looks dimmer (less red) but no green for the 1000 or 800

maybe I will hook it up to my new fluidic cooler mini lab system later and try it at a power level harder then what my palm can sink

or maybe they meant low power levels in total darkness to see it. because they say frequency of blinking lets ppl see the light in remote controls or something in strange colors

IR_Geek:

--- Quote from: DaJMasta on April 15, 2024, 04:04:00 am ---...

If you're trying to capture all the light from your source and accurately pass it to a spectrometer or similar for measurement, look at integrating spheres - not cheap, but basically a matte reflective material all over a spherical interior surface with some mechanism to hold/power a device in the middle.

--- End quote ---

DajMasta has it nailed.   That peaks in the NIR band and what you are seeing is the edges of the spectrum.   Depending on a persons ability, they will see slightly different coloring.   Also there is the photopic (cones) vs scotopic (rods) that our eyes see for color (bright) and b/w (low light).     There should be a data sheet showing the full spectrum.   An example from Mouser ... https://www.mouser.com/datasheet/2/723/XLamp_XPE2-3402122.pdf    on page 14 there is a chart showing all the spectrums from that lineup of LED's.  I included a screenshot from page 14.  Note the spread of wavelengths for each LED.   

The purple you remember is probably from a camera looking at the LED

_Wim_:

--- Quote from: DaJMasta on April 15, 2024, 04:04:00 am ---...look at integrating spheres - not cheap, but basically a matte reflective material all over a spherical interior surface with some mechanism to hold/power a device in the middle.

--- End quote ---

Quite possible to DIY also for not that high of a cost, see

Styrofoam hollow spheres that can be bought at a crafts store also work as quite an acceptable sphere. What kind of spectrometer you want to use it with?

coppercone2:
I found video of a 740 nm laser, its red, pretty sure that guy can see it. but alot of manufacturers claim that 750nm is the end of visible range. the laser diode should be really narrow band, but its a little expenisve

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