Light Emitting Unit with Metal Layer for Crosstalk Reduction
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Solution Overview
Problem
Existing LED display technologies face issues with light propagation through resin, leading to degradation of red LEDs, crosstalk, color temperature changes, and reduced color reproduction due to blue and green light incidence, affecting the optical output and viewing angle dependence.
Innovation Solution
A light emitting unit with a semiconductor layer structure including a first and second conductive layer, an active layer, a first insulation layer, and a metal layer, where the metal layer is electrically separated from the electrodes and covers the side surface of the light emitting elements to reflect internal light and prevent incidence on adjacent elements, reducing the impact of light propagation within the resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If light emitting elements are mounted on a wiring substrate to form an LED display, then the display achieves fast response speed and no viewing angle dependence, but the production process becomes complex and difficult to achieve high production rate
Solution Approach 1:
The invention divides the display into independent light emitting units, each containing multiple light emitting elements (red, green, blue LEDs) arranged in a specific pattern. Each unit is self-contained with its own resin layer, allowing for simplified mounting and assembly processes while maintaining the performance benefits of individual LED control
Solution Approach 2:
Multiple light emitting elements of different colors (red, green, blue LEDs) are combined within a single light emitting unit structure, with all elements embedded in a common resin layer. This merging approach simplifies the overall display construction by reducing the number of separate components that need to be mounted and connected
2Reliability
If blue light propagates through the resin to reach red LED, then the red LED material (polyimide) degrades, but blocking the light requires additional structures that increase device complexity
Solution Approach 1:
The resin layer serves as an intermediary medium that optically isolates the light emitting elements. By carefully selecting resin materials with appropriate optical properties (such as refractive index matching or absorption characteristics), the resin prevents harmful blue light from reaching red LED elements while still allowing the desired light to propagate effectively
Solution Approach 2:
The resin layer is designed with specific local optical properties tailored to the particular arrangement of light emitting elements. The resin's optical characteristics are optimized for the local configuration of red, green, and blue LEDs within each unit, providing targeted protection where needed while maintaining overall light emission efficiency
3Object-affected harmful factors
If green light propagates through the resin and reaches red LED, then the red LED is excited and emits light, causing crosstalk and color temperature changes, but preventing this requires additional light blocking measures
Solution Approach 1:
The resin layer acts as an optical intermediary that prevents unwanted light interactions between different colored LEDs. By selecting resin materials with appropriate absorption spectra, the resin blocks green light from exciting red LED elements while maintaining the desired optical performance for the primary light emission paths
Solution Approach 2:
The optical parameters of the resin (such as absorption coefficient, refractive index) are specifically selected and optimized to change the propagation characteristics of different wavelengths. The resin is designed to absorb or block specific wavelengths (green light) while allowing other wavelengths to pass through, thereby preventing crosstalk without requiring additional physical barriers
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 minimizes the negative effects of light propagation on the resin, such as degradation and crosstalk, while maintaining the pressure resistance of the light emitting elements and enhancing color reproduction and viewing angle stability.
Implementation Method 1
the light propagating toward the inside of the lamination surface may be reflected by the metal layer installed at the side surface of the light emitting element to disturb light incidence to an adjacent light emitting element
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A light emitting unit including plural kinds of light emitting elements with different light emitting wavelengths, wherein, among the light emitting elements, at least one kind of light emitting element includes a semiconductor layer configured by laminating a first conductive layer, an active layer and a second conductive layer and having a side surface exposed by the first conductive layer, the active layer and the second conductive layer; a first electrode electrically connected to the first conductive layer; a second electrode electrically connected to the second conductive layer; a first insulation layer contacting at least an exposed surface of the active layer in the surface of the semiconductor layer; and a metal layer contacting at least a surface, which is opposite to the exposed surface of the active layer, in the surface of the first insulation layer, and electrically separated from the first electrode and the second electrode.