led light range

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northernbob
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led light range

Post by northernbob » Thu Feb 22, 2018 2:21 am

anyone worked with modern leds?

i know they can produce light in any part of the visible spectrum, but can they be used to go beyound say 700nm eg 750 or higher?

this is near IR range.

going below 450nm is dangerous, so have to go up over....

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myelin
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Re: led light range

Post by myelin » Thu Feb 22, 2018 2:26 am

Probably not on topic for the 8-bit hardware board... maybe move this to miscellaneous < off-topic?
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richard_fry
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Re: led light range

Post by richard_fry » Thu Feb 22, 2018 3:48 am

Not that I've used them, but 'Far Red' LEDs are above 700nm typically around 730nm
Had a quick google...
RapidLED list a Far Red LED on their website.
ProlightOpto list a 'Cherry Red' LED which is typ 730nm =/- 10nm
LED Engin list a Far red LED with wavelength 723-745nm
Other than that, GlobalSources / Alibaba do show LEDs up to 780nm

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1024MAK
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Re: led light range

Post by 1024MAK » Thu Feb 22, 2018 1:45 pm

There are roughly three LED types:-
  • Single colour LEDs, where the colour (wavelength) is determined by the materials used to make the semiconductor material, these are the traditional IR, red, orange, yellow, green and more recently the blue LEDs,
  • LEDs which emit a single colour (typically blue) light which is then is changed to another colour by putting a suitable phosphor coating between the LED chip and the outer case, with these, as long as there is a suitable phosphor, you can have any colour you like, most white LEDs are this type,
  • multichip LEDs, where there red, green and blue LED chips in the same package. Then a control chip switches these LEDs to produce the wanted colour.
The single colour LEDs includes LEDs which emit IR light. These are used in remote controls for example and other applications where visible light is not wanted or needed.

Wikipedia has a nice table with the relevant colours and wavelengths here :wink:

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