Lighting Apparatus Reducing Discomfort Glare via Segmented Color Temperature
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Solution Overview
Problem
High correlated color temperature light radiation from luminaires, such as those used in road lighting, causes discomfort glare, and existing solutions that cut off light at high incident angles can adversely affect luminaire performance.
Innovation Solution
A lighting apparatus and method that distribute light radiation with a first portion at a lower correlated color temperature (≤3000K) at a wider incident angle range (70-90 degrees) and a second portion at a higher correlated color temperature (4000K-6500K) at a narrower angle range (<70 degrees), reducing discomfort glare by increasing adaptation luminance and maintaining sufficient luminous intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high correlated color temperature light radiation is used to provide sufficient luminous intensity, then illumination performance is improved, but discomfort glare increases
Solution Approach 1:
The light radiation is segmented into two distinct portions based on incident angle: a first portion at high incident angles (70-90 degrees) with lower correlated color temperature (≤3000K) and a second portion at lower incident angles (<70 degrees) with higher correlated color temperature (4000K-6500K). This segmentation allows each portion to serve different functions - the first portion increases adaptation luminance to reduce glare while the second portion provides sufficient illuminance for visual tasks.
Solution Approach 2:
Different quality characteristics (correlated color temperatures) are assigned to different spatial regions (incident angle ranges) of the light radiation. The high incident angle region receives warmer light (≤3000K) optimized for glare reduction, while the low incident angle region receives cooler light (4000K-6500K) optimized for illumination performance. This local quality differentiation resolves the contradiction by optimizing each region for its specific function.
2Object-affected harmful factors
If light radiation is cut off at high incident angles to reduce discomfort glare, then glare perception is reduced, but luminaire performance deteriorates
Solution Approach 1:
Instead of cutting off light radiation at high incident angles as in conventional solutions, this invention inverts the approach by specifically directing light radiation with optimized correlated color temperature (≤3000K) to the high incident angle range (70-90 degrees). This inverted strategy maintains luminaire performance by preserving the light distribution while transforming the quality characteristic to achieve glare reduction.
Solution Approach 2:
The correlated color temperature parameter is changed as a function of incident angle. By varying the correlated color temperature parameter across different incident angle ranges - warmer temperatures (≤3000K) for high angles and cooler temperatures (4000K-6500K) for lower angles - the invention achieves both glare reduction and maintained luminaire performance without cutting off any light radiation.
3Object-affected harmful factors
If light radiation with low correlated color temperature is used to increase adaptation luminance, then discomfort glare is reduced, but luminous intensity for illumination decreases
Solution Approach 1:
The illumination function is segmented between two portions of light radiation with different correlated color temperatures. The first portion (≤3000K) at high incident angles serves primarily to increase adaptation luminance and reduce glare, while the second portion (4000K-6500K) at lower incident angles provides the luminous intensity needed for illumination. This segmentation allows both functions to be fulfilled without compromise.
Solution Approach 2:
The invention merges two distinct light radiation portions with different correlated color temperatures into a single integrated lighting system. By combining the glare-reducing effect of warm light at high angles with the illumination-providing effect of cool light at lower angles, the system achieves both comfort and performance simultaneously, rather than requiring separate lighting systems.
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
Significantly reduces discomfort glare perception while maintaining effective illumination, as demonstrated by the deBoer rating improvement from 5.00 to 6.00, and is compatible with existing luminaire designs.
Implementation Method 1
converting the first portion of the light radiation by light filtering or luminescent process
Data Source
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AI summary
There is provided a lighting apparatus and a method for reducing discomfort glare. The method comprises a step of providing a first portion of light radiation in a first incident angle range; and another step of providing a second portion of light radiation in a second incident angle range consecutive to the first incident angle range. The first incident angle range is greater than the second incident angle range viewed from a vertically downward direction of a light source emitting the light radiation, and the correlated color temperature of the first portion of light radiation is lower than that of the second portion of light radiation.