confusion between nm (Nanometer) of LED's

[gauravkothari23]

hi all...
i have a small confusion regarding nm or nanometer in UV LED.
i just want to ask more nm means more distance of light and more superior. actually i am ordering UV LED's for PCB developing.
i have checked that
420nm to 430nm = 6 $ (10 pcs)
395nm to 400nm = 6.50 $ (10 pcs)
3.80nm to 3.85nm = 8 $ (10 pcs)
365nm to 370nm = 21 $ (10 pcs)
why is it that.... more nm lesser the price, when more nm makes the LED more superior
i am bit confused... can you help me for the same.

 

[FvM]

nm is unit of light wavelength or light "color", not related to "distance".

Down to 380 nm is still visible light. Shorter wavelength LED is difficult to produce and thus more expensive.

Preference for a specific wavelength depends completely on the application. What's your application for UV LEDs?

 

[gauravkothari23]

nm is unit of light wavelength or light "color", not related to "distance".

Down to 380 nm is still visible light. Shorter wavelength LED is difficult to produce and thus more expensive.

Preference for a specific wavelength depends completely on the application. What's your application for UV LEDs?

i need UV LED's for PCB manufacturing and prototypes.

 

[FvM]

O.K., PCB exposure box. Shorter wavelength will be more effective for exposure, but only if you have no UV absorbing acryl glass window. Absolute LED intensity however matters, too. Need to compare the emitted light power.

Fluorescent UV tubes may be still the simpler method.