Wavelength Conversion Layer Wall Geometry for Light Leakage Control
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Solution Overview
Problem
Conventional light emitting devices face challenges in suppressing light leakage from the top surface of the wall, which affects the efficiency and contrast of the emitted light.
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 a hollow opening portion exposing the top surface of the wavelength conversion layer, and the angle of the corner portion between the top surface and the inner surface of the wall is between 90 degrees and 180 degrees, enhancing light reflection and reducing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the wall completely surrounds the wavelength conversion layer, then light leakage is reduced, but light extraction efficiency decreases due to excessive reflection into the wall
Solution Approach 1:
The wall is segmented into a first wall portion and a second wall portion, with the second portion having a smaller inner diameter than the first portion. This segmentation allows different regions of the wall to serve different functions: the first portion reflects light while the second portion with the opening allows light extraction, thus resolving the contradiction between preventing light leakage and maintaining light extraction efficiency.
Solution Approach 2:
An opening portion is extracted from the second wall portion, exposing the top surface of the wavelength conversion layer. This extraction creates a dedicated light extraction path that separates the light reflection function (performed by the wall portions) from the light extraction function (performed through the opening), thereby resolving the energy loss contradiction.
2Ease of manufacture
If the corner portion angle is less than 90 degrees, then manufacturing is easier, but light leakage occurs at the corner
Solution Approach 1:
The corner portion angle is specifically designed to be 90 degrees or more and less than 180 degrees, optimizing the balance between manufacturing ease and light leakage prevention. This parameter change ensures that light incident on the inner surface is reflected effectively without leaking, while still being manufacturable using conventional processes.
3Device complexity
If the wall top surface is at the same level as the wavelength conversion layer, then device structure is simplified, but light leakage from wall top surface occurs
Solution Approach 1:
The wall top surface is positioned at a different height (vertical dimension) than the wavelength conversion layer top surface, with the wall top surface being higher. This dimensional change creates a geometric configuration where the corner portion can effectively reflect light away from the wall top surface, preventing light leakage while maintaining relatively simple device structure.
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, improving the light extraction efficiency and contrast between the peripheral region and the region directly above the light emitting element and wavelength conversion layer.
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.