Tilted Parabolic Optic for LED Light Guide Coupling
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Solution Overview
Problem
Adapting parabolic optics for LED light sources to efficiently focus light into light guides has proven difficult, especially with linear arrays, due to alignment issues and the need for specific exit apertures, which are not practicable with conventional compound parabolic concentrators.
Innovation Solution
A light assembly with a linear array of LEDs and a primary optic featuring a reflecting surface with a parabolic cross-section and a tilted bisector of parabolic cross-section, allowing for efficient light emission into light guides with a 20-degree angle in both directions perpendicular to the optical axis, and approximated by polygonal or linear segments tangent to a parabolic cross-section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional compound parabolic concentrator (CPC) is used with a linear array of LEDs, then the light collection is improved, but the alignment complexity and difficulty of achieving specific exit apertures increases
Solution Approach 1:
The patent merges the CPC reflector and the light guide into a single integrated component. The CPC reflector is formed as an integral part of the light guide assembly, eliminating the need for separate alignment of multiple components. This integration maintains effective light collection while significantly reducing alignment complexity and manufacturing difficulty.
2Illumination intensity
If each LED in a 2×3 chip array is used with an individual optic, then light concentration is improved, but the cost and manufacturing difficulty increases
Solution Approach 1:
The patent combines multiple individual LED optics into a single shared CPC reflector structure that serves the entire linear array of LEDs. This unified reflector design maintains effective light concentration for each LED while dramatically simplifying manufacturing by eliminating the need to produce and assemble multiple individual optic components.
Solution Approach 2:
The single CPC reflector structure serves multiple functions: it collects light from all LEDs in the linear array, concentrates the light, and directs it into the light guide. This multi-functional design replaces what would otherwise require multiple specialized components, reducing both manufacturing complexity and cost.
3Stability of the object's composition
If the entrance size is dictated by the physical dimensions of the LED array, then the LED array configuration is maintained, but the adaptability for different light guide sizes is reduced
Solution Approach 1:
The patent creates a dynamic, adjustable entrance aperture within the CPC reflector structure. The entrance size and shape can be modified independently of the LED array physical dimensions, allowing the same LED array configuration to adapt to different light guide sizes and requirements while maintaining stable LED positioning and electrical connections.
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
This configuration provides a 30% reduction in exit aperture width, enabling optimal coupling to light guides with larger tolerances and improved efficiency, reducing light loss and alignment complexities.
Implementation Method 1
An optic, which can a primary optic, is provided about the LEDs and has a reflecting surface associated therewith. The reflecting surface has a parabolic cross-section
Implementation Method 2
an optic with a parabolic surface generated by the standard formula, Z=1⁄4f·R2, such as those used in PAR lamps, is an efficient concentrator of light
Data Source
AI summary
A light assembly (100) for directing light into a light guide utilizes a light source (120) comprising a linear array of light emitting diodes (140). The linear array has two opposed long sides (160, 180) equally disposed about a longitudinal axis (162) and two opposed short sides (200, 220) and is positioned in a mounting plane (240). The array has an optical plane (250) lying in a plane perpendicular to the mounting plane (240). A primary optic (260) having a reflecting surface (270) is associated therewith, the reflecting surface (270) having a parabolic cross-section and a focal point (280) and a bisector of parabolic cross-section (282) wherein the focal point (280) is disposed at one of the long sides (160, 180) of the array (140) and the bisector of parabolic cross-section (282) has an axis (283) that is tilted with respect to the optical plane (250). In a preferred embodiment, the axis (283) of the bisector of parabolic cross-section (282) is tilted about 8 degrees. The construction provides an arrangement for feeding light from the array into a light guide.