Dual-Sided LED Electrode Layout for Inverted Transfer Reliability
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Solution Overview
Problem
The challenge lies in accurately and efficiently transferring light-emitting diode (LED) devices from a semiconductor substrate to a display device substrate while minimizing defects and misorientation, which affects the reliability and productivity of the display device due to the complexity and cost of the transfer process, particularly with the use of expensive semiconductor substrates and the vulnerability of organic light-emitting devices to moisture and oxygen.
Innovation Solution
A light-emitting device design with n-type and p-type semiconductor layers disposed on both sides of an active layer, along with electrodes on both top and bottom surfaces, allows for electrical connection even when inverted, reducing defects and damage from abnormal currents, and includes a configuration where the first and second semiconductor layers operate independently to block or allow current based on bias states, ensuring reliable light emission and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If LED devices are transferred from semiconductor substrate to display device substrate, then the display device can achieve thinner shape and flexibility, but the transfer process complexity and cost increase
Solution Approach 1:
A transfer substrate is introduced as an intermediary component between the semiconductor substrate and the display device substrate. The LED devices are first formed on the semiconductor substrate, then transferred to the transfer substrate, and finally mounted on the display device substrate. This intermediary transfer substrate simplifies the overall transfer process and reduces complexity by breaking down the direct transfer into manageable stages.
2Length of moving object
If LED devices are transferred from semiconductor substrate to display device substrate, then the display device can achieve thinner shape and flexibility, but the risk of defects and misorientation increases
Solution Approach 1:
The LED devices are pre-formed on the semiconductor substrate with proper orientation and configuration before transfer. The transfer substrate is prepared in advance with appropriate structures to receive and hold the LED devices. This preliminary preparation ensures that when the transfer occurs, the devices maintain their correct orientation and reduce the risk of misorientation defects.
Solution Approach 2:
The transfer substrate serves as a protective intermediary that handles the LED devices during transfer, minimizing direct handling and reducing the risk of defects. It provides a stable platform that maintains device integrity throughout the transfer process from semiconductor substrate to display device substrate.
3Device complexity
If electrodes are disposed only on top surface of LED device, then the structure is simpler, but the device is vulnerable to damage from abnormal currents and misorientation
Solution Approach 1:
The electrode structure is segmented into multiple independent electrodes disposed on both the top and bottom surfaces of the LED device. This segmentation allows different electrodes to serve different functions - some for normal operation and others for protection against abnormal currents. The separated electrodes can independently respond to different electrical conditions, enhancing overall device reliability.
Solution Approach 2:
Protective electrodes are disposed on both top and bottom surfaces in advance to cushion against potential abnormal currents before they can cause damage. These electrodes are positioned to intercept and dissipate abnormal electrical energy, providing beforehand protection against electrical surges, reverse bias damage, and other abnormal conditions that may occur during device operation or transfer.
4Reliability
If multiple electrodes are disposed on both top and bottom surfaces of LED device, then protection against abnormal currents is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The formation of multiple electrodes on both top and bottom surfaces is merged into integrated processing steps. The electrodes are formed using combined deposition and patterning processes that simultaneously create multiple electrode structures rather than forming them separately. This merging of manufacturing steps reduces the overall complexity despite the increased number of electrodes, making the process more efficient and easier to manufacture.
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 design enhances the reliability and longevity of light-emitting devices by ensuring electrical connections are maintained even during misorientation, reduces defects in the transfer process, and protects against abnormal currents, thereby improving the productivity and reliability of the display device.
Implementation Method 1
a first light-emitting diode (LED) device, including: an n-type semiconductor layer; a p-type semiconductor layer; an active layer, wherein the n-type semiconductor layer and the p-type semiconductor layer are disposed on both sides of the active layer
Data Source
AI summary
A light-emitting device and a display device using the same are disclosed. The light-emitting device improves the reliability of a process of disposing light-emitting devices. The light-emitting device is configured to ensure electrical connections even if the light-emitting device is inverted while being disposed on a substrate. The light-emitting device includes an n-type semiconductor layer and a p-type semiconductor layer. N-type electrodes and p-type electrodes are disposed on both sides of top and bottom surfaces of the light-emitting device. Contact holes are provided to electrically connect one of the n-type electrodes to the n-type semiconductor layer and one of the p-type electrodes to the p-type semiconductor layer. When the light-emitting device is inverted while being disposed on a substrate, the light-emitting device operates ordinarily, thereby reducing the defect rate of a display device.