Light Emitting Device with TIR Redirecting Elements
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Solution Overview
Problem
Volume emitting LEDs in arrays face challenges such as non-Lambertian emission profiles, reduced design freedom due to close packing, and cross-talk leading to efficiency loss and color shift, making them non-compliant with standards like the Zhaga standard and resulting in suboptimal beam quality.
Innovation Solution
A light emitting device with a substrate and an optical structure featuring light redirecting elements, such as V-shaped grooves, that utilize total internal reflection to redirect light emitted by volume emitting LEDs, improving Lambertian emission and allowing for wider spacing without efficiency loss or color shift, while maintaining high beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If volume emitting LEDs are closely packed to achieve good beam quality, then beam quality is improved, but design freedom is reduced and cross-talk increases causing efficiency loss and color shift
Solution Approach 1:
The patent introduces an optical structure with light redirecting elements (such as V-shaped grooves) as an intermediary between the volume emitting LEDs and the exit surface. This mediator redirects the non-Lambertian light from closely packed LEDs into a Lambertian emission pattern, allowing close packing for beam quality while avoiding cross-talk issues through the optical redirection mechanism
2Illumination intensity
If volume emitting LEDs are closely packed to achieve good beam quality, then beam quality is improved, but cross-talk increases causing efficiency loss and color shift
Solution Approach 1:
The optical structure is segmented into multiple light redirecting elements (such as V-shaped grooves) that are distributed across the surface. Each segment independently redirects light from nearby LEDs, creating discrete optical zones that prevent cross-talk between adjacent LEDs while maintaining overall beam quality
3Adaptability or versatility
If volume emitting LEDs are spaced wider to maintain design freedom, then design freedom is improved, but cross-talk decreases causing efficiency loss and color shift
Solution Approach 1:
The optical structure with light redirecting elements serves as an intermediary that allows LEDs to be spaced at optimal distances for design freedom while the optical elements ensure that light is properly redirected and contained, preventing efficiency loss that would otherwise require closer spacing
4Productivity
If volume emitting LEDs are used in arrays, then productivity is improved, but emission profile becomes non-Lambertian reducing compliance with standards
Solution Approach 1:
The patent changes the optical parameters of the light emission by introducing light redirecting elements with specific geometries (such as V-shaped grooves with particular angles). This parameter change transforms the emission profile from non-Lambertian to Lambertian, enabling array configurations to comply with standards like Zhaga while maintaining high productivity
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 achieves a highly Lambertian emission profile, enhances design freedom, reduces cross-talk, and maintains constant beam quality even with wider LED spacing, ensuring compliance with standards like the Zhaga standard with minimal efficiency loss.
Implementation Method 1
a second section comprising a plurality of light redirecting elements adapted for redirecting light emitted by the plurality of volume emitting LEDs towards said surface of the optical structure by means of total internal reflection (TIR)
Data Source
AI summary
A light emitting device (1) comprising a plurality of volume emitting LEDs (21-29) adapted for, in operation, emitting light, a substrate (3) on which said plurality of volume emitting LEDs is arranged, and an optical structure (4) comprising a surface (41) adapted for forming a light exit surface of the light emitting device, a first section (5) arranged such as to extend over said plurality of volume emitting LEDs opposite to the substrate, and a second section (6) comprising a plurality of light redirecting elements (61-68) adapted for redirecting light emitted by the plurality of volume emitting LEDs towards said surface of the optical structure by means of total internal reflection (TIR), the plurality of light redirecting elements (61-68) extending between adjacent volume emitting LEDs of the plurality of volume emitting LEDs and terminating adjacent to the substrate (3).