Light Emitting Device Chromaticity Control via Three-Source Segmentation
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Solution Overview
Problem
Existing light-emitting devices struggle to achieve a wide range of chromaticity due to the locus of chromaticity moving on a straight line in the 1931 CIE chromaticity diagram when current levels are adjusted, limiting the expression of chromaticity points beyond this line.
Innovation Solution
A light-emitting device comprising three light sources with peak emission wavelengths in the ranges of 430-480 nm, 430-480 nm, and 490-570 nm, connected in parallel, and encapsulated with phosphors, allowing for independent adjustment of current levels to each source to achieve a wide range of chromaticity and color temperature, including 2000 K to 7500 K, by positioning the third light source's chromaticity point above the line defined by the first two sources in the 1931 CIE chromaticity diagram.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two light sources with peak emission wavelengths in the range of 430 nm to 480 nm are used, then the chromaticity can be adjusted along a straight line in the 1931 CIE chromaticity diagram, but the chromaticity other than on the substantially straight line is difficult to be expressed
Solution Approach 1:
The light-emitting device is divided into three separate light sources instead of using a single light source or two light sources. Each light source has a specific peak emission wavelength range (430-480 nm for first and second, 490-570 nm for third), allowing independent control of chromaticity components to achieve broader chromaticity coverage
Solution Approach 2:
By adding the third light source with peak emission wavelength in the range of 490 nm to 570 nm, the chromaticity adjustment moves from a one-dimensional straight line (with two light sources) to a two-dimensional area in the 1931 CIE chromaticity diagram, enabling expression of chromaticity points that were previously inaccessible
2Adaptability or versatility
If multiple light sources with different peak emission wavelengths are added to expand chromaticity range, then the chromaticity coverage is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent specifies precise peak emission wavelength ranges for each light source (430-480 nm for first and second, 490-570 nm for third) to optimize chromaticity coverage. By controlling the spectral parameters of each light source within these ranges, the device achieves broad chromaticity coverage while maintaining manufacturability through standardized wavelength specifications
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 device can emit light with a wide range of chromaticity and color temperatures, enabling the reproduction of desired chromaticity points beyond the straight line locus, providing high-quality emission colors with minimal color difference at the same temperature.
Implementation Method 1
an encapsulant containing a phosphor and covering the first light source, the second light source, and the third light source
Data Source
AI summary
A light-emitting device includes: a first light source including a first light-emitting element having a peak emission wavelength in a range of 430 nm to 480 nm; a second light source including a second light-emitting element having a peak emission wavelength in a range of 430 nm to 480 nm; a third light source; and an encapsulant containing a phosphor. In a 1931 CIE chromaticity diagram, the light-emitting device has: a first chromaticity point when only the first light source is operated, a second chromaticity point different from the first chromaticity point when only the second light source is operated, and a third chromaticity point when only the third light source is operated, the third chromaticity point having a y-value larger than a y-value on a straight line passing the first chromaticity point and the second chromaticity point.