Off-Axis Flashlight

Right-Angle Flashlight     .

Optical layout	Engineering mockup.  The production model uses a molded parabolic reflector.	LED visible over entire diameter

The Right-Angle Flashlight

      The goal was to maximize the efficiency of flashlights.  The field-of-illumination from the LED is aimed at the off-axis parabola, which reflects all of the light in a focused beam.  No light is wasted.  

       If you look directly into the front of the flashlight (with the light off, for your safety) you will see that the entire diameter reflects the LED.  There is no central dead spot from the LED as with conventional flashlights.  

      The improved efficiency of the off-axis flashlight allows the manufacturer to increase the brightness using the same LED, or provide the same brightness with a less-expensive LED.  

Conventional flashlights…

      Conventional flashlights use a parabolic reflector, surrounding the LED.  Only the LED’s side-field is reflected by the rim of the parabolic reflector, which misses the brightest part of the LED in the center.  

Original lab notebook entry:

Notebook #2,  p. 70