Wavelength Conversion Wall Structure to Suppress Light Leakage
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Solution Overview
Problem
Conventional light emitting devices experience light leakage from the top surface of the wall, which reduces efficiency and contrast.
Innovation Solution
A light emitting device design featuring a substrate, a light emitting element, a wavelength conversion layer, and a wall with a light reflective material, where the wall has an opening portion exposing the wavelength conversion layer and is structured to suppress light leakage by controlling the angle of the corner portions between the top surface and inner surface of the wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the wall completely surrounds the wavelength conversion layer, then light leakage is prevented, but light extraction efficiency decreases due to light propagating into the wall and leaking from the top surface
Solution Approach 1:
The wall is divided into a first portion surrounding the wavelength conversion layer and a second portion provided over the first portion, creating a stepped structure. This segmentation allows different regions of the wall to serve different functions: the first portion contains propagating light while the second portion with the opening exposes the wavelength conversion layer for efficient light extraction.
Solution Approach 2:
The wall structure implements local quality by having different configurations in different regions. The first portion has a configuration optimized for containing light, while the second portion features an opening portion that exposes the wavelength conversion layer for optimal light extraction. The corner portion angle (90-180 degrees) is specifically designed to prevent light leakage locally while maintaining overall efficiency.
2Ease of manufacture
If the wall top surface is positioned at the same level as the wavelength conversion layer top surface, then manufacturing is simplified, but light leakage occurs from the top surface
Solution Approach 1:
The wall structure extends in the vertical dimension by positioning the top surface of the wall higher than the top surface of the wavelength conversion layer. This dimensional change creates a stepped configuration that effectively prevents light leakage from the top surface while maintaining manufacturing feasibility through the two-stage wall formation process.
3Productivity
If the corner portion angle is less than 90 degrees, then light propagation into the wall is reduced, but light leakage increases from the top surface
Solution Approach 1:
The corner portion angle is specifically designed to be in the range of 90 degrees or greater and less than 180 degrees. This parameter optimization balances two competing requirements: maintaining sufficient angle to prevent light leakage from the top surface while keeping the angle small enough to limit light propagation into the wall, thereby achieving both light containment and extraction efficiency.
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 design effectively suppresses light leakage from the top surface of the wall, enhancing the contrast and light extraction efficiency of the light emitting device.
Implementation Method 1
a wall that contains a light reflective material, surrounds the wavelength conversion layer
Implementation Method 2
a wavelength conversion layer that is provided on the light emitting element and converts a wavelength of a part of the first light to emit second light
Data Source
AI summary
A light emitting device includes: a substrate; a light emitting element; a wavelength conversion layer; and a wall surrounding the wavelength conversion layer, having an opening portion exposing at least a part of a top surface of the wavelength conversion layer, and containing a light reflective material. The surface of the wall includes a top surface provided at a higher position than the top surface of the wavelength conversion layer, and an inner surface forming the opening portion. The wall includes a first portion surrounding the wavelength conversion layer, and a second portion provided over the first portion and surrounding the first portion. The opening portion is hollow. An angle of a corner portion between the top surface and the inner surface of the wall is in a range of 90 degrees or greater and less than 180 degrees.