Off-Axis Flashlight
Off-Axis Flashlight .
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| Optical layout | Engineering mockup. | LED visible over entire diameter |
The HinesLab Off-Axis Flashlight…
The goal of this project was to maximize the efficiency of LED flashlights. A 60° field-of-illumination LED is positioned just below the barrel, and is aimed at the off-axis parabola, which reflects all of the light in a focused beam. No light is wasted. If desired, a diffusing lens can be used to create a soft glow around the central bright spot.
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-wattage 60° (vs 120°) LED.
– – – or – – –
- Maintain the same brightness with a less-expensive, lower-wattage 60° (vs 120°) LED for longer battery life, or redesign using smaller, lighter-weight batteries.
Conventional flashlights…
Conventional flashlights use a circular parabolic reflector, surrounding a 120° LED. Only the LED’s side-field illumination (around the edge) is captured by the rim of the parabolic reflector, which misses the brightest part of the LED in the center.
Original lab notebook entry:
This is a technology announcement and license offer. Please contact Steve Hines with questions.