Hi, looking for a sensor that I can use to map out the light spread of a 405nm UV LED.
Had a look in the usual places for hobby sensors and come across units like the VEML6075, VEML6070, SI1145, and ML8511 but not found anything that range is over 390nm.
Are there LDRs tuned for specific wavelengths?
that I can use to map out the light spread of a 405nm UV LED.
What is "light spread"?
Can you give a better explanation for what you are trying to do?
There are no LDRs tuned to different wavelengths, however an LED is a color sensitive light detector.
jremington:
What is "light spread"?Can you give a better explanation for what you are trying to do?
Sure, Im trying to calibrate a resin printer that uses a 405nm LED to project light through an LCD screen to cure photoreactive resin
As the LED is in the center of the screen the light levels are lower as its spreads to the edge of the screen, resulting in longer cure ties for the resin in at the edges.
This can be mitigated using a "mask" the measurement of the spread of light at various points on the LCD and via software darkening points with higher UV levels to give a median level across the whole LCD.
The closer the sensors range is to the LED (in tis case 405nm) the better the results of the mask and the better print quality across the full range of the printer.
Hope that helps explain a little better?
Try a 355nm UV LED as detector.
Agree, 355 nm LED used in zero bias (photovoltaic) mode will give quantitative intensity measurements at 405 nm.
Best to use a rail-to-rail op amp that includes ground in the input range, otherwise just about any op amp with a bipolar power supply will work. See this overview.
why not use a 405 nm LED for sensing? There seem to be many options, including through-hole.</dumb question>
DaveEvans:
...why not use a 405 nm LED for sensing?
According to the article in post#1.
"LEDs detect a much narrower band of light, having a peak sensitivity at a wavelength slightly shorter than the peak wavelength they emit."
Leo..
Could I use one of these LM393 sensor boards and just switch out the LED/LDR with a 355 nm LED? (just wondering as I have a couple here to hand)
Wawa:
According to the article in post#1.
"LEDs detect a much narrower band of light, having a peak sensitivity at a wavelength slightly shorter than the peak wavelength they emit."
Leo..
Thanks.
