LED Wavelength Conversion Layer for Uniform Color
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Light-emitting diodes (LEDs) with phosphor layers for wavelength conversion result in non-uniform color distribution when viewed from different angles due to varying mixing ratios of the remaining LED light and converted light, leading to inconsistent color appearance.
Innovation Solution
A light-emitting device design featuring a light-emitting element with a wavelength conversion layer, where the wavelength conversion layer has specific height and width configurations on the top and side surfaces to ensure uniform light mixing and conversion, maintaining consistent color across different angles of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a phosphor layer is covered on the LED for wavelength conversion, then the LED can emit converted light with different wavelength, but the mixed light has non-uniform color distribution in different angles of view
Solution Approach 1:
The patent applies local quality by creating different thickness regions in the wavelength conversion layer: a first thickness in the first area and a second thickness in the second area. This non-uniform thickness distribution allows different local regions to convert light differently, compensating for the angular dependence of light mixing and achieving uniform color distribution across different viewing angles.
Solution Approach 2:
The patent transitions from a two-dimensional planar phosphor layer to a three-dimensional structured wavelength conversion layer with varying thickness. By introducing the thickness dimension, the patent creates a depth profile that optimizes light conversion at different angles, resolving the color uniformity issue while maintaining conversion efficiency.
2Ease of manufacture
If the wavelength conversion layer has uniform thickness, then the manufacturing process is simple, but the color distribution becomes non-uniform in different angles of view
Solution Approach 1:
The patent implements local quality by specifying that the wavelength conversion layer has a first thickness in a first area and a second thickness in a second area, where the thicknesses differ. This localized thickness variation optimizes color consistency across different viewing angles while remaining manufacturable through standard semiconductor fabrication techniques.
3Quantity of substance
If the wavelength conversion layer thickness is increased, then more LED light is converted, but the mixing ratio of remaining LED light and converted light varies in different angles
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying thickness: the wavelength conversion layer has a first thickness in a first area and a second thickness in a second area. This allows different regions to contribute differently to the overall light conversion, maintaining uniform mixing ratios across angles while achieving high conversion quantities.
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 configuration of the wavelength conversion layer on the light-emitting device ensures a uniform color distribution across various angles of view, improving the color consistency and light extraction efficiency by optimizing the mixing ratio of the LED light and converted light.
Implementation Method 1
The phosphor is a photoluminescence and wavelength conversion material. It can absorb a first light from the LED and emit a second light different from the first light.
Data Source
AI summary
A light-emitting device includes a light-emitting element and a wavelength conversion layer. The light-emitting element has a top surface, a bottom surface, a side surface, and a first electrical contact formed on the bottom surface. The distance between the top surface and the bottom surface has a first height (h1). The wavelength conversion layer has a first area (A1) located on the top surface of the light-emitting element and a second area (A2) located on the side surfaces and surrounding the first area. The first area has a second height (h2). The second area has a third height (h3) and a second width (w2). The second height (h2) is greater than the second width (w2). The difference of the third height and the sum of the first height and the second height is less than 15 μm.