LED Light-Shielding Layer Structure for High-Contrast Displays
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) in public information displays suffer from low contrast ratios due to light absorption by black encapsulation materials, reducing light efficiency and luminance.
Innovation Solution
A light-emitting element with a double-layer light-shielding layer, comprising a high reflectivity light reflective layer and a light absorption layer, is used to enhance light utilization efficiency by allowing direct emission of light through an opening in the light-shielding layer, while the absorption layer reduces ambient light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If black encapsulation material is used to block ambient light, then contrast ratio is improved, but light utilization efficiency deteriorates
Solution Approach 1:
The light-shielding function is segmented from the encapsulation material and implemented by a separate light-shielding layer with opening. This allows the encapsulation material to be transparent (not absorbing light) while the dedicated light-shielding layer blocks ambient light from specific directions, resolving the contradiction between light shielding and light transmission.
Solution Approach 2:
The light-shielding layer has an opening that allows light to pass through in specific regions while blocking it in other regions. The opening is positioned to allow emitted light to pass through while blocking ambient light from specific angles, creating local differences in light transmission properties to resolve the contradiction.
2Object-affected harmful factors
If light-shielding layer is added to block ambient light, then contrast ratio is improved, but device structure complexity increases
Solution Approach 1:
The light-shielding layer is merged with the encapsulation structure, forming an integrated component. The light-shielding layer with opening is combined with the lens-shaped encapsulation material, reducing the need for separate light-shielding components and simplifying the overall device structure while maintaining effective ambient light blocking.
3Loss of energy
If opening is provided in light-shielding layer for light emission, then light utilization efficiency is improved, but ambient light blocking capability deteriorates
Solution Approach 1:
The light-shielding layer has an opening that allows light to pass through in specific regions while blocking it in other regions. The opening is positioned and sized to allow emitted light to pass through while blocking ambient light from specific angles, creating local differences in light transmission properties to resolve the contradiction.
Solution Approach 2:
The solution moves from a two-dimensional planar light-shielding approach to a three-dimensional structure with the light-shielding layer wrapped around the lens-shaped encapsulation material. This dimensional change allows the opening to be positioned strategically to permit light emission while blocking ambient light from multiple directions.
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 increases light utilization efficiency and contrast ratio by concentrating light emission and minimizing ambient light interference, thereby improving the overall luminance and image quality in outdoor displays.
Implementation Method 1
the inner layer of the light-shielding layer is a light reflective layer which can increase the amount of light emitting through the opening
Implementation Method 2
the outer layer of the light-shielding layer is a light absorption layer, and therefore the reflective ratio of ambient light can be decreased
Data Source
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AI summary
A light emitting element (100) includes a package substrate (102), a first light-emitting diode chip (104, 104G, 104R, or 104B), an encapsulation material (106) and a light-shielding layer (108). The first light-emitting diode chip (104, 104G, 104R, or 104B) is disposed on the package substrate (102), the encapsulation material (106) is disposed on the first light-emitting diode chip (104, 104G, 104R, or 104B) and the package substrate (102), and the light-shielding layer (108) is disposed on the encapsulation material (106) and has a first opening (108a). In a top-view direction, the area (A1) of the first opening (108a) of the light-shielding layer (108) is less than the area (A2) of the light emitting element (100).