Nonimaging Flashlight Lens for Circular Beam Output
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Solution Overview
Problem
Existing nonimaging light assemblies for flashlights lack improved beam characteristics, particularly in compact flashlights, where there is a need for a high intensity core beam surrounded by a smoothly transitioning lower intensity surround beam.
Innovation Solution
A nonimaging light assembly featuring a light source and a symmetrical lens with a refractive first rear surface, an aspheric refractive second rear surface, and a total-internal reflection (TIR) side surface, optimized using the NICOS software to produce a light beam with a concentrated core and divergent surround, resulting in a substantially circular cross-section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional light assembly with simple lens is used, then the device complexity is low, but the beam characteristics are insufficient (cannot produce high intensity core beam with smoothly transitioning surround beam)
Solution Approach 1:
The lens is divided into multiple functional surfaces: a first rear surface, a second rear surface, a side surface, and a front surface. Each surface is optimized to perform specific light manipulation functions, enabling the complex beam pattern (high intensity core with surround beam) through segmented optical processing rather than a single complex surface
Solution Approach 2:
Different regions of the lens have different optical properties and functions. The first rear surface handles light from the LED chip center, the second rear surface handles light from other angles, the side surface provides TIR for specific ray paths, and the front surface shapes the final beam. This local specialization enables sophisticated beam control while keeping each individual surface relatively simple
2Shape
If a square LED light source is used, then the manufacturing simplicity is high, but the output beam cross-section is not circular
Solution Approach 1:
The lens structure is deliberately designed with asymmetric surface configurations relative to the square LED chip. The first rear surface, second rear surface, side surface, and front surface are positioned and shaped to compensate for the square geometry of the LED, transforming the asymmetric square light emission into a symmetric circular beam cross-section through careful optical design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution generates a high intensity core beam surrounded by a smoothly transitioning lower intensity surround beam, enhancing the beam characteristics of flashlights and achieving a circular cross-section output from a square light emitting diode source.
Implementation Method 1
an aspheric total-internal reflection (TIR) side surface for total-internally reflecting and concentrating light received by the second rear surface
Implementation Method 2
a refractive first rear surface intersecting the optical axis for receiving a first portion of the light emanating from the light source positioned along the optical axis
Data Source
AI summary
A nonimaging light assembly for flashlights, including a light source and a lens symmetrical about an optical axis for receiving light from the light source and producing therefrom a light beam having concentrated and divergent components resulting in a high intensity core beam surrounded by a smoothly transitioning lower intensity surround beam. In a preferred embodiment utilizing a light emitting diode as the light source, the combined light beam produced by the light assembly has a substantially circular cross section.