Stacked Light-Emitting Element With Light-Shielding Portion
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Solution Overview
Problem
Existing light-emitting elements face issues with emission variability due to crystal defects in low-temperature polysilicon and low carrier mobility, and drive circuit malfunctions caused by light striking CMOS transistors, limiting high-speed operation and proper emission.
Innovation Solution
A light-emitting element is designed with a stacked configuration of a light-emitting diode layer and a drive circuit layer, where a light-shielding portion is used to prevent light from reaching the drive circuits, and electrodes connect the layers electrically, allowing for shared conductivity regions and isolation structures to demarcate pixels, ensuring effective light emission and high-speed driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If low-temperature polysilicon (LTPS) is used for drive circuits, then integration with compound semiconductors is enabled, but crystal defects at grain boundaries cause threshold value variability and emission variability among pixels
Solution Approach 1:
The invention divides the drive circuit into multiple independent pixel units, each with its own transistor and light-emitting element. By isolating the drive circuits into discrete pixel regions with isolation structures, the variability caused by LTPS crystal defects is confined to individual pixels rather than affecting the entire display, thereby maintaining emission uniformity across all pixels.
Solution Approach 2:
The invention applies different material properties and structural characteristics to different regions: LTPS is used specifically in the drive circuit regions where high-speed switching is needed, while isolation structures are placed in specific locations to contain defects. This localized application allows the system to exploit the advantages of LTPS while mitigating its disadvantages through region-specific design.
2Adaptability or versatility
If amorphous silicon or low-temperature polysilicon is used for TFT integrated circuits, then stacking on compound semiconductors is enabled, but low carrier mobility limits high-speed driving capability
Solution Approach 1:
The invention changes the material parameter from amorphous silicon to low-temperature polysilicon, which has higher carrier mobility. This parameter change enables high-speed driving capability while maintaining the stacking capability with compound semiconductors, as LTPS can still be processed at compatible temperatures and integrated with the light-emitting elements.
3Area of stationary object
If drive circuits are placed close to light-emitting elements for compact integration, then miniaturization is achieved, but light may strike the drive circuits causing malfunction
Solution Approach 1:
The invention segments the device into distinct functional regions: light-emitting regions and drive circuit regions. Isolation structures are placed between these regions to physically separate them, preventing light from striking the drive circuits while maintaining compact integration. This segmentation allows miniaturization without compromising circuit operation stability.
Solution Approach 2:
The invention introduces isolation structures as intermediary elements between the light-emitting elements and drive circuits. These isolation structures act as mediators that block light propagation to the drive circuits while allowing electrical connections to be maintained, thus enabling compact integration without light-induced malfunctions.
4Ease of manufacture
If laser recrystallization technique is used for LTPS, then transistor formation is enabled, but special equipment is required increasing device complexity
Solution Approach 1:
The invention changes the processing temperature parameter to enable low-temperature polysilicon formation without requiring laser recrystallization equipment. By using processing temperatures below 650°C, the invention achieves transistor fabrication capability while avoiding the need for special laser equipment, thus reducing device complexity.
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 solution enables more appropriate light emission and high-speed driving by preventing light-induced malfunctions in drive circuits and reducing emission variability, achieving stable and efficient operation of the light-emitting element.
Implementation Method 1
a first member having a light-emitting diode layer formed therein
Data Source
AI summary
A light-emitting element in which a first member having a light-emitting diode layer formed therein, and a second member having a drive circuit layer formed therein, are stacked and bonded to each other, wherein the light-emitting diode layer and the drive circuit layer are electrically connected by an electrode; the second member includes a light-shielding portion different from the electrode; the light-shielding portion is disposed so as to cover at least part of a first pixel and a second pixel demarcated by an isolation structure provided in the light-emitting diode layer; and a layer that forms the light-emitting diode layer in the first pixel and a layer that forms the light-emitting diode layer in the second pixel are shared.