The Math Behind the Dwarvin System

You may be wondering if you could just use a regular LED to light fiber optics. The answer is yes, if you only want a pin point of light at the end of a fiber. However, this will not enable the lighting of buildings or street lights.

Why is this?

  • Light is measured in Lumens. The lower the Lumens the less intense the light. The higher the Lumens, the more intense and brighter the light.
  • A typical 20mA LED puts out about 10 lumens beamed out over 135 degrees from the lens (meaning it is not in any way focused). The singular LED light itself is typically about 5mm away from the surface area of the lens. At this small distance, the beam of light from the singular LED covers an area of 460 mm2.
  • A 1.5mm diameter optical fiber is only able to pick up 0.4% of the light at its illuminated end (the actual source of light). The area of the 1.5mm diameter optical fiber (1.8 mm2) divided by the area of the light source (460 mm2) = 0.004 (0.4%) of light at the point of pickup.
  • This means (0.004 (light pickup) times 10 lumens = 0.04 Lumens at the output end of the fiber optic (pretty weak).
  • The Dwarvin Lamplighter™ Box puts out 200+ lumens which is focused through internal optics into a 6mm diameter beam, which has a corresponding surface area of 32 mm2.
  • The area of the 1.5mm diameter optical fiber (1.8 mm2) divided by the area of the Lamplighter focused light (32 mm2) = 0.056 (5.6%) of light at the point of pickup.
  • This means (0.056 (light pickup) times 200 (lumens) = 112 Lumens at the output end of the fiber optic (significantly brighter!).
  • So, if we take 112 Lumens divided by 0.4 Lumens we see that optical fibers lit with the Lamplighter is 280 TIMES brighter than an optical fiber used with a 20mA LED.
  • Again, in terms of light collection from the Lamplighter box, this amounts to 10 lumens of light collection.
  • This is 250 times brighter than one can get from a 20mA LED going into a single fiber!
  • On top of this, a single fiber provides as much light as a single 20mA LED, but without any wiring

So, to answer the original question, you can illuminate a fiber optic with a standard LED, however, optical fibers transfer much more light when the source of light is focused. Which is the real advantage of using the Lamplighter products over standard LED’s to illuminate fiber optics.