Light-emitting Device Wall Light Leakage Reduction
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Solution Overview
Problem
Existing light-emitting devices face issues with light leakage from the upper surface of the wall, which affects the brightness and contrast of the peripheral regions surrounding the light-emitting element and wavelength conversion layer.
Innovation Solution
A light-emitting device configuration that includes a substrate, a light-emitting element, a wavelength conversion layer with protrusions and recesses, a light-transmissive plate with an air layer in between, and a wall made of light-reflective material surrounding the wavelength conversion layer and light-transmissive plate, where the upper surface of the wavelength conversion layer has protrusions and recesses, and the wall is designed to inhibit light leakage by attenuating the second light within the wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a wall containing light-reflective material surrounds the wavelength conversion layer, then light extraction efficiency is improved, but light leaks from the upper surface of the wall causing reduced contrast and brightness
Solution Approach 1:
A light-absorbing layer is introduced as an intermediary between the wavelength conversion layer and the wall containing light-reflective material. This intermediary layer absorbs the second light (converted wavelength) before it can propagate into the wall and leak from the upper surface, thereby eliminating the harmful light leakage while preserving the light extraction efficiency benefits of the reflective wall structure.
Solution Approach 2:
The harmful effect of light leakage is extracted and addressed by selectively removing the problematic light propagation path. The light-absorbing layer is positioned to specifically intercept and absorb the second light that would otherwise enter the wall and leak from its upper surface, separating the useful light extraction function from the harmful light leakage effect.
2Illumination intensity
If light-reflective material is used in the wall, then luminance is enhanced, but peripheral region contrast deteriorates due to light leakage
Solution Approach 1:
The light-absorbing layer serves as a mediator that allows the wall to maintain its light-reflective properties for enhancing luminance while simultaneously preventing light leakage that would degrade peripheral region contrast. The absorptive layer is strategically positioned to intercept only the light that would cause contrast deterioration.
3Illumination intensity
If the wall is made light-reflective to improve brightness, then light leakage occurs reducing image quality
Solution Approach 1:
The light-absorbing layer converts the potentially harmful light that would leak from the wall into a beneficial effect by absorbing it. The second light that reaches the light-absorbing layer is converted into heat or other non-radiative energy, preventing it from leaking and degrading image quality, while the wall's reflective properties continue to enhance brightness.
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 effectively reduces light leakage from the upper surface of the wall, enhances the luminance of the light-emitting device, and improves the contrast between the peripheral region and the region directly above the light-emitting element and wavelength conversion layer, while maintaining high light extraction efficiency.
Implementation Method 1
a wavelength conversion layer provided on the light-emitting element and containing a plurality of wavelength conversion particles adapted to convert a wavelength of a part of the first light and to emit a second light
Implementation Method 2
a wall containing a light-reflective material, the wall surrounding the wavelength conversion layer and the light-transmissive plate
Implementation Method 3
an air layer is provided between the wavelength conversion layer and the light-transmissive plate
Data Source
AI summary
A light-emitting device includes a substrate, a light-emitting element provided on the substrate, the light-emitting element being configured to emit a first light, a wavelength conversion layer provided on the light-emitting element and containing a plurality of wavelength conversion particles configured to convert a wavelength of a part of the first light and to emit a second light, a light-transmissive plate provided above the wavelength conversion layer, and a wall including a light-reflective material, the wall surrounding the wavelength conversion layer and the light-transmissive plate and being in contact with a lateral surface of the light-transmissive plate at an inner surface of the wall. An upper portion of the wavelength conversion layer includes protrusions and recesses defined by the plurality of wavelength conversion particles. The wavelength conversion layer and the light-transmissive plate define an air layer therebetween.