Special thanks to a CPF member who sent me the Nichia UV LEDs for testing.
I played around with them and took some shots to compare the 360nm Fox Group, 375nm Nichia and 400nm Radio Shack UV LEDs. First the specs:
Fox Group Part #: FG360-R5--WC015
Peak wave length: 361nm, half power points at +/- 5nm (approx)
Lifetime: retains over 90% output after 1200 hours at 20ma
Typical Vf at 20ma is 3.8
30ma max, 80ma pulse
Ordinary handling precautions: static sensitive, 5v max reverse, DO NOT look into operating LED!
Nichia NSPU510CS
Peak wave length: 375nm typ. Half points +/- 7.5nm
Lifetime: better than 1,000 hours at 15ma
Typical Vf at 20ma is 3.6
20ma max, 80ma pulse
Nichia NSHU591A (metal can LED)
Similar to other Nichia, but with 25ma max forward current.
It has a narrower beam with lower overall output.
Both Nichia LEDs contain a reverse bias protection diode.
The metal can diode emits a dim white light for some reason.
Radio Shack 276-014
wavelength: 395nm (minimum), 410nm (maximum)
Viewing angle: 30°
FW current: 20mA; FW supply: 3.2 (typical), 3.8V (maximum)
LED emitters L-R: Fox Group, Nichia, RS, Nichia metal can. The epoxy LEDs look like ordinary 5mm indicator LEDs. With a strong magnifier, I can see an extra bond wire and protection diode in the Nichia. Reverse bias drive confirms its existence.
Beam shot from white wall. The paint does not fluoresce from the UV light, but the camera's sensor does respond to the 375nm slightly and the 400nm LED strongly. Camera sensors include a UV filter, so wavelengths shorter than 400nm show weakly.
To the human eye, the 400nm LED shows as a dim violet color. This light is beyond the camera's gamut. Since the light gets through the blue filtered pixel, it is processed as blue and thus shows blue in the image.
Here the LEDs light up a strip of fluorescent orange construction paper. The Fox Group LED is the double spot on the left, Nichia center, RS Right. They each have different beam angles. RS claims 30 Deg, but I've gotten packages that were wide angle and some narrow. This one seems more like a 15 Degree beam.
All the LEDs lit up the security strip on a US $20 bill. This is the Nichia. It did the job by far the best. The Fox LED is too narrow and feeble. The RS LED is hard to see because of the interfering blue glow. With the RS LED, you can see the strip better when viewing the bill from the opposite side of the LED.
In this series of shots, I locked the camera's exposure meter and shot through different types of acrylic to see how it blocks the various bands of UV.
1st. This is with nothing in front of the LEDs. Same result with ordinary soda-lime glass. most radiation passes right through.
2nd. Standard clear acrylic (Plexi). Ordinary acrylic has a UV stabilizer and filter in it that blocks UV strongly at 360nm and shorter wave lengths. It passes some 375nm and lets all of the 400nm through.
3rd. Special UV blocking acrylic is used for covering art objects to prevent fading. There is also a UV blocking glass as well. As you can see, it blocks the 360, 375 almost totally and even blocks some of the 400nm. Result was the same when testing my haze-1 Tiffen camera lens filter. I did find out that some generic UV filters are fake! They did not block the radiation from these LEDs!
Conclusion:
These UV LEDs are sure fun to tinker with! I wish I had more materials to check how they glow under the UV.
Fox Group LED. This LED has a vary narrow beam that images the die. Output is low and the frequency of the UV probably also hinders its ability to make objects glow. I'd say it is designed for special scientific uses that need this wavelength.
Nichia. To me, these resemble an ordinary black light the most. They output very little visible light that would hinder photography and visual observance of glowing objects/minerals. They have excellent output at 375nm. These get my highest recommendation.
RS UV. These make day glow paints and construction papers glow bright. The problem is, because the human eye and camera (especially the camera) are so sensitive to its visible output, it hinders the observing of glowing paints and chemicals. Some substances/minerals may not glow that well with it anyway. OTOH it is probably the best choice for making fluorescent paints and construction paper projects glow brightly because these LEDs are relatively cheap.
Stay tuned! I have some super efficient white Nichia Raijin flux style LEDs on the way for fade testing (thanks to another CPF member for sending them). I will also have updates to the other fade tests coming.
I played around with them and took some shots to compare the 360nm Fox Group, 375nm Nichia and 400nm Radio Shack UV LEDs. First the specs:
Fox Group Part #: FG360-R5--WC015
Peak wave length: 361nm, half power points at +/- 5nm (approx)
Lifetime: retains over 90% output after 1200 hours at 20ma
Typical Vf at 20ma is 3.8
30ma max, 80ma pulse
Ordinary handling precautions: static sensitive, 5v max reverse, DO NOT look into operating LED!
Nichia NSPU510CS
Peak wave length: 375nm typ. Half points +/- 7.5nm
Lifetime: better than 1,000 hours at 15ma
Typical Vf at 20ma is 3.6
20ma max, 80ma pulse
Nichia NSHU591A (metal can LED)
Similar to other Nichia, but with 25ma max forward current.
It has a narrower beam with lower overall output.
Both Nichia LEDs contain a reverse bias protection diode.
The metal can diode emits a dim white light for some reason.
Radio Shack 276-014
wavelength: 395nm (minimum), 410nm (maximum)
Viewing angle: 30°
FW current: 20mA; FW supply: 3.2 (typical), 3.8V (maximum)
LED emitters L-R: Fox Group, Nichia, RS, Nichia metal can. The epoxy LEDs look like ordinary 5mm indicator LEDs. With a strong magnifier, I can see an extra bond wire and protection diode in the Nichia. Reverse bias drive confirms its existence.
Beam shot from white wall. The paint does not fluoresce from the UV light, but the camera's sensor does respond to the 375nm slightly and the 400nm LED strongly. Camera sensors include a UV filter, so wavelengths shorter than 400nm show weakly.
To the human eye, the 400nm LED shows as a dim violet color. This light is beyond the camera's gamut. Since the light gets through the blue filtered pixel, it is processed as blue and thus shows blue in the image.
Here the LEDs light up a strip of fluorescent orange construction paper. The Fox Group LED is the double spot on the left, Nichia center, RS Right. They each have different beam angles. RS claims 30 Deg, but I've gotten packages that were wide angle and some narrow. This one seems more like a 15 Degree beam.
All the LEDs lit up the security strip on a US $20 bill. This is the Nichia. It did the job by far the best. The Fox LED is too narrow and feeble. The RS LED is hard to see because of the interfering blue glow. With the RS LED, you can see the strip better when viewing the bill from the opposite side of the LED.
In this series of shots, I locked the camera's exposure meter and shot through different types of acrylic to see how it blocks the various bands of UV.
1st. This is with nothing in front of the LEDs. Same result with ordinary soda-lime glass. most radiation passes right through.
2nd. Standard clear acrylic (Plexi). Ordinary acrylic has a UV stabilizer and filter in it that blocks UV strongly at 360nm and shorter wave lengths. It passes some 375nm and lets all of the 400nm through.
3rd. Special UV blocking acrylic is used for covering art objects to prevent fading. There is also a UV blocking glass as well. As you can see, it blocks the 360, 375 almost totally and even blocks some of the 400nm. Result was the same when testing my haze-1 Tiffen camera lens filter. I did find out that some generic UV filters are fake! They did not block the radiation from these LEDs!
Conclusion:
These UV LEDs are sure fun to tinker with! I wish I had more materials to check how they glow under the UV.
Fox Group LED. This LED has a vary narrow beam that images the die. Output is low and the frequency of the UV probably also hinders its ability to make objects glow. I'd say it is designed for special scientific uses that need this wavelength.
Nichia. To me, these resemble an ordinary black light the most. They output very little visible light that would hinder photography and visual observance of glowing objects/minerals. They have excellent output at 375nm. These get my highest recommendation.
RS UV. These make day glow paints and construction papers glow bright. The problem is, because the human eye and camera (especially the camera) are so sensitive to its visible output, it hinders the observing of glowing paints and chemicals. Some substances/minerals may not glow that well with it anyway. OTOH it is probably the best choice for making fluorescent paints and construction paper projects glow brightly because these LEDs are relatively cheap.
Stay tuned! I have some super efficient white Nichia Raijin flux style LEDs on the way for fade testing (thanks to another CPF member for sending them). I will also have updates to the other fade tests coming.
Last edited:
