LED Side Reflection Layer for Narrow Viewing Angle and High Light Output
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Solution Overview
Problem
Light emitting diodes (LEDs) face challenges in achieving high output performance with narrow viewing angles and uniform color rendering, particularly due to size reduction leading to reduced light output and luminous efficacy, as well as issues with phosphor mixing and heat sensitivity.
Innovation Solution
The LED design incorporates a light blocking layer to define a smaller light emitting surface, uses ceramic plate phosphors for high temperature resistance, and arranges wavelength converters to prevent interference, ensuring efficient light conversion and reduced color deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the light emitting diode chip size is reduced to achieve narrow viewing angle, then the viewing angle is narrowed, but the light output is reduced
Solution Approach 1:
The patent applies local quality by introducing a side reflection layer specifically at the side surfaces of the LED chip. This localized structural modification reflects light that would otherwise be lost sideways back toward the light emitting surface, thereby enhancing light output without changing the overall chip size or viewing angle characteristics.
2Illumination intensity
If the current density is increased to compensate for reduced light output, then the light output is increased, but the luminous efficacy deteriorates due to drooping phenomenon
Solution Approach 1:
The patent converts the harmful effect of light loss at the side surfaces into a beneficial effect. The side reflection layer captures light that would otherwise be wasted and redirects it to the light emitting surface, effectively increasing light output without increasing current density, thus avoiding the drooping phenomenon and maintaining luminous efficacy.
3Ease of manufacture
If multiple kinds of phosphors are used to improve color rendering, then the color rendering properties are improved, but uniform mixing is difficult and color deviation occurs
Solution Approach 1:
The patent applies segmentation by dividing the phosphor application into separate, non-overlapping regions. Different kinds of phosphors are applied to different areas of the light emitting surface, preventing mixing issues and color deviation while still achieving improved color rendering properties through the combination of multiple phosphor types.
4Ease of manufacture
If phosphors are mixed with transparent resin to achieve mixed color, then the color mixing is achieved, but the resin is vulnerable to heat
Solution Approach 1:
The patent extracts the phosphors from the transparent resin matrix and applies them directly to the light emitting surface in separate regions. This eliminates the heat-vulnerable resin component while maintaining the color mixing function through spatial arrangement of different phosphors, thereby improving heat resistance.
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 allows for high output performance without increasing current density, maintaining luminous efficacy, and enhances color rendering properties while reducing color deviation and heat sensitivity.
Implementation Method 1
a side reflection layer covering the side surfaces of the substrate and the upper surface of the substrate along an edge of the upper surface of the substrate
Implementation Method 2
employ wavelength converters containing different kinds of phosphors
Data Source
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AI summary
A light emitting diode including a light blocking layer is disclosed. The light emitting diode includes: a substrate including an upper surface and side surfaces; a semiconductor stack disposed under the substrate and including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer interposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer; and a light blocking layer covering the upper surface and the side surfaces of the substrate to define a light emitting surface on the upper surface of the substrate. The size of a light emitting surface of the light emitting diode can be easily controlled using the light blocking layer.