LED Light Source Chromaticity Adjustment via Surface Scattering
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Solution Overview
Problem
Existing LED light sources with wavelength-converted fluorescent materials face challenges in maintaining consistent chromaticity due to variations in the amount and dispersion of the fluorescent material, leading to difficulties in mass production and potential damage during chromaticity adjustment methods that involve altering the transparent resin layer.
Innovation Solution
The implementation of light scattering sections on the surface of the sealing material around the LED device, which scatter a portion of the emitted light to adjust chromaticity without altering the outer shape or damaging the LED light source, by forming projections and depressions in various patterns to control the light path and increase or decrease the wavelength-conversion rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the amount of fluorescent material in sealing material is increased to adjust chromaticity toward yellow, then chromaticity shifts toward yellow region, but chromaticity variation between individual LED light sources increases making mass production difficult
Solution Approach 1:
The patent applies parameter changes by modifying the thickness of the transparent resin layer rather than changing the amount of fluorescent material. By controlling the resin layer thickness parameter, the optical path length is adjusted, which changes the wavelength conversion rate and thus the chromaticity. This approach maintains chromaticity consistency while avoiding the manufacturing variability associated with fluorescent material dispersion.
2Manufacturing precision
If transparent resin layer is polished or coated to adjust chromaticity, then chromaticity can be adjusted, but the LED light source may be damaged or its outer shape altered
Solution Approach 1:
The patent uses a mold to create a replicated surface structure on the transparent resin layer. Instead of directly polishing or coating the LED light source (which could damage it), the desired surface pattern is copied from a master mold. This replicated structure provides the necessary light scattering effect for chromaticity adjustment while maintaining the integrity and outer shape of the original LED light source.
3Manufacturing precision
If fluorescent material dispersion is improved to reduce chromaticity variation, then chromaticity consistency improves, but manufacturing complexity increases
Solution Approach 1:
The patent changes the approach from controlling fluorescent material parameters (amount and dispersion) to controlling the transparent resin layer thickness parameter. This parameter change simplifies the manufacturing process because thickness control through molding is more straightforward than controlling fluorescent material dispersion. The solution moves the control variable to a parameter that is easier to manage in mass production while achieving the same chromaticity uniformity goal.
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 method allows for easy adjustment of chromaticity while preventing damage to the LED light source, maintaining its outer shape and ensuring consistent chromaticity across individual units, thereby facilitating mass production.
Implementation Method 1
a first fluorescent material is mixed in resin of sealing material 106. The fluorescent material absorbs and wavelength-converts a portion of the light emitted from LED device 101 to emit light from itself
Implementation Method 2
light scattering sections 107 are formed in a circle in a region 71 within a critical angle on a surface 108 of sealing material 106
Data Source
AI summary
There is provided an LED light source whose chromaticity can be adjusted easily without changing its outer shape and suffering damage in the process of chromaticity adjustment. An LED light source includes an LED device, a fluorescent material that absorbs and wavelength-converts a portion of light emitted from the LED device to emit light from itself, a sealing material that includes the fluorescent material and that is disposed around the LED device, and light scattering sections that are formed at a portion of a surface of the sealing material and scatter a portion of the light emitted from the LED device for adjusting chromaticity of the LED light source, and a chromaticity adjustment method for such LED light source.