kramer5150
Flashaholic
Curious... why are no LED manufacturers developing lower Vf emitters? Wouldn't lower Vf emitters help improve 1AA performance?
Lowering Vf?
- Thread starter kramer5150
- Start date
Help Support Candle Power Flashlight Forum
RelativeEng
Newly Enlightened
- Joined
- Jul 27, 2009
- Messages
- 22
Changing forward voltage is not as easy as you think. The Vf of a diode is based on the semiconductor and the doping agent used to make it. The electromotive force (voltage) required to bridge between the two regions is what dictates this Vf. Remember, you are "forcing" an electron from a higher orbit of an atom to a lower orbit. It is when this "drop" occurs that a photon (light) is released.
If you wanted to lower the Vf of a die, you would have to change the materials involved relative atomic mass. This is why the forward voltage of white LEDs and color LEDs are different. The relative atomic mass is more proportionate which requires less voltage to conduct. This lower drop emitts a lower energy which you see as a different wavelength (color).
If you wanted to lower the Vf of a die, you would have to change the materials involved relative atomic mass. This is why the forward voltage of white LEDs and color LEDs are different. The relative atomic mass is more proportionate which requires less voltage to conduct. This lower drop emitts a lower energy which you see as a different wavelength (color).
lolzertank
Enlightened
Unless we start using NIR LEDs with phosphor to make white light, it's actually impossible to drop the Vf to 1xAA levels. Right now, LED manufacturers usually use 450-460nm blue light which is then converted into white light. Unfortunately, that also means the minimum possible Vf is about 2.75V for the reasons RelativeEng mentioned.
