Polygonal Light-Emitting Device Reduces Color Unevenness
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Solution Overview
Problem
The existing light-emitting devices with blue and green light-emitting elements exhibit unevenness in emission color due to the high straightness of blue and green light emission.
Innovation Solution
A light-emitting device design featuring an inner n-sided polygonal light-emitting element with a peak emission wavelength of 490 nm to 570 nm, surrounded by m outer light-emitting elements with a peak emission wavelength of 430 nm to 490 nm, and a first phosphor with a peak emission wavelength of 580 nm to 680 nm, where each lateral surface of the inner element faces corresponding outer elements, effectively mixing their light emissions to reduce color unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue and green light-emitting elements are used to achieve high color reproducibility, then color rendering is improved, but emission color uniformity deteriorates due to high straightness of light emission
Solution Approach 1:
A yellow phosphor layer is introduced as an intermediary between the blue and green light-emitting elements. This yellow phosphor converts a portion of the blue light into yellow light, which then mixes with the green light emission. The yellow phosphor acts as a mediator that softens the high straightness of the blue and green light emissions, thereby improving emission color uniformity while maintaining good color reproducibility through the combination of direct green emission and phosphor-converted yellow emission.
2Illumination intensity
If multiple light-emitting elements with different wavelengths are arranged together, then color reproducibility is improved, but device complexity increases
Solution Approach 1:
The patent combines blue and green light-emitting elements in a side-by-side arrangement with a yellow phosphor layer positioned to receive blue light and emit yellow light that mixes with green light. This merging approach achieves broad spectral coverage for improved color reproducibility while maintaining a relatively simple planar structure. The integration of the phosphor layer with the light-emitting elements creates a unified device architecture that delivers enhanced color performance without proportionally increasing structural complexity.
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 configuration significantly reduces color unevenness in the light-emitting device, allowing for improved color reproducibility and emission intensity, particularly suitable for liquid-crystal display applications.
Implementation Method 1
a first phosphor with a peak emission wavelength in a range of 580 nm to 680 nm covering the inner light-emitting element and the m outer light-emitting elements
Data Source
AI summary
A light-emitting device includes an inner light-emitting element having an n-sided polygonal shape (n is an integer of 3 or more) in a plan view with a peak emission wavelength in a range of 490 nm to 570 nm; m (m is an integer of 3 or more) outer light-emitting elements with a peak emission wavelength of 430 nm or greater and less than 490 nm; and a first phosphor with a peak emission wavelength in a range of 580 nm to 680 nm covering the inner light-emitting element and the m outer light-emitting elements. Each of n lateral surfaces of the inner light-emitting element faces a corresponding one of the m outer light-emitting elements in a top view.