LED Light Source Wavelength Bin Combination for Color Consistency
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Solution Overview
Problem
Existing LED-based light sources for white light emitting devices experience significant color and color temperature variations due to the dominant wavelength of excitation light, leading to inconsistent light output, especially when using phosphor materials for wavelength conversion.
Innovation Solution
The use of a combination of LEDs from different wavelength bins within a single package to generate excitation light with a selected dominant wavelength, reducing the variation in the emitted light's dominant wavelength and enabling more consistent white light production by combining LEDs from bins with varying dominant wavelengths, thereby minimizing color shifts and improving color rendering index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single wavelength bin LED is used, then manufacturing precision is easier to achieve, but color consistency deteriorates due to dominant wavelength variation
Solution Approach 1:
The patent combines multiple LEDs from different wavelength bins (e.g., 440-445nm, 445-450nm, 450-455nm) within a single package to create a composite light source. This merging approach averages out the dominant wavelength variations of individual LEDs, achieving superior color consistency (within 2 MacAdam ellipses) while maintaining ease of manufacturing through standardized wavelength bin selection.
2Ease of manufacture
If LEDs from broader wavelength bins are used, then cost decreases, but color precision deteriorates
Solution Approach 1:
The patent enables the use of LEDs from broader, less expensive wavelength bins by combining multiple such LEDs in a package. The composite spectral output of multiple broader-bin LEDs achieves narrower effective wavelength variation than a single LED from a tight bin, thus improving color precision while maintaining cost effectiveness through the use of standard commercial LED bins.
3Reliability
If phosphor material is positioned remotely, then thermal degradation is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the light emitting system into distinct functional modules: multiple LED chips mounted on a substrate, and a separate photoluminescence wavelength conversion component positioned remotely. This segmentation allows the phosphor material to be thermally isolated from the LED heat sources while maintaining optical coupling, thus improving phosphor stability without requiring complex integrated structures.
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 results in a more consistent light output with a dominant wavelength variation within a fraction of the original bin range, achieving light consistency within two MacAdam ellipses and enhancing the Color Rendering Index, while allowing the use of less expensive LEDs from broader wavelength bins.
Implementation Method 1
at least one photoluminescence material that is operable to convert, through a process of photoluminescence, at least a portion of the excitation light to light of a different wavelength
Implementation Method 2
LED-based (Light Emitting Diode-based) light sources
Data Source
AI summary
An LED-based light source for generating light having a selected dominant wavelength λds comprises a package housing a plurality of LEDs consisting of LEDs from first and second wavelength bins. The first wavelength bin comprises LEDs having a dominant wavelength λd1 that is within a first wavelength range and the second wavelength bin comprises LEDs having a dominant wavelength λd2 that is within a second wavelength range. The first wavelength bin can comprise LEDs having a dominant wavelength that is shorter than the selected dominant wavelength while the second wavelength bin comprises LEDs having a dominant wavelength that is longer than the selected dominant wavelength. The wavelength bins and number of LEDs are selected such that in operation the dominant wavelength of the combined light emitted by the source is the selected dominant wavelength. Lighting arrangements and light emitting devices incorporating such light sources are disclosed.