Segmented Light Guide for High-CRI Spot Lighting
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Solution Overview
Problem
Current lighting devices struggle to produce white light with high intensity and high color rendering index (CRI) for high-end spot lighting applications, due to limitations in available materials and the need for significant amounts of red light, which can be difficult to achieve with existing phosphors and transparent red materials.
Innovation Solution
A segmented light guide with photo-luminescent materials that convert light into specific wavelength ranges, allowing for the mixing of different wavelengths within the guide to produce white light, where each segment is 'pumped' with light from a light source, and includes a configuration that reflects incident light back into the guide to minimize losses and reduce the required amount of direct red light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional phosphors and transparent red materials are used to generate white light, then the color rendering index (CRI) can be improved, but the intensity and luminous flux are insufficient for high-end spot lighting applications
Solution Approach 1:
The light guide is divided into multiple segments along its length, with each segment containing phosphors that convert light to specific wavelength ranges. This segmentation allows different portions of the light guide to emit different colors, enabling precise control over the spectral composition and intensity of the output light, thereby achieving high CRI white light with sufficient intensity without requiring excessive red light
2Illumination intensity
If a segmented light guide with wavelength-converting phosphors is used, then white light with high CRI and high intensity can be produced, but the device complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated light guide structure. The light guide simultaneously performs light transmission, wavelength conversion through embedded phosphors in segmented regions, and light emission. This merging of functions achieves high brightness white light with high CRI while avoiding the need for separate optical components and complex assembly, thereby managing device complexity
3Force
If red light is significantly increased to improve CRI, then the color rendering index can be improved, but the material limitations and difficulty in achieving high intensity are worsened
Solution Approach 1:
Different segments of the light guide are assigned different phosphor compositions tailored to emit specific wavelength ranges. This local quality approach allows each segment to be optimized for its specific function, using materials best suited for that wavelength range, thereby achieving high CRI through coordinated emission from multiple segments rather than relying on any single material with limited performance
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 approach enables the production of white light with high brightness and high CRI, reducing the need for excessive red light and overcoming material limitations, thus achieving a high luminous flux in a compact form.
Implementation Method 1
The light guide comprises a plurality of segments, where each segment is configured to convert at least a part of light input therein into light having a selected wavelength range
Implementation Method 2
which can subsequently be extracted from a light exit surface of the light guide, leading to a high intensity gain
Data Source
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AI summary
A lighting device (20, 40) is disclosed. The lighting device (20, 40) comprises a segmented light guide (19), comprising a plurality of segments (21, 22), where each segment (21, 22) may be 'pumped' with light via respective first light in-coupling surfaces located on a lateral surface of the light guide (19), and where each of the segments (21, 22) is configured to convert at least a part of light input therein into light having a selected wavelength range. The light guide (19) extends in an axial direction between a first base surface (25) at one end (23) of the light guide (19) and a second base surface (26) at another end (24) of the light guide (19), the first base surface (25) and the second base surface (26) being located on different ones of the segments (21, 22). At least a portion of the first base surface (25) comprises a second light in-coupling surface for coupling of light into the light guide (19) and at least a portion of the second base surface (26) comprises a light out- coupling surface for coupling of light out of the light guide (19). The lighting device (20, 40) comprises at least one first light-emitting element (29) configured to emit light of a first wavelength range and being optically coupled to the second light in-coupling surface such that light emitted by the at least one first light-emitting element (29) is coupled into the light guide (19) via the second light in-coupling surface, wherein the at least one first light- emitting element (29) is configured so as to reflect at least part of incident light thereon having a wavelength within at least one of the selected wavelength ranges back into the light guide (19).