Light Emitting Device Voltage Distribution and ESD Protection
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Solution Overview
Problem
Existing stacked semiconductor light emitting devices face challenges in improving quality and reducing manufacturing costs due to the distribution of circuit elements across multiple substrates, with existing solutions not effectively addressing voltage differences and electrostatic discharge resistance.
Innovation Solution
A light emitting device is designed with a first substrate having a higher maximum voltage and a protective circuit to safeguard unit circuits, while a second substrate with a lower maximum voltage includes control circuits, optimizing voltage distribution and incorporating protective circuits to enhance electrostatic discharge resistance without requiring new manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If circuit elements are distributed across multiple substrates in a stacked configuration, then device integration is improved, but voltage distribution and electrostatic discharge resistance become problematic
Solution Approach 1:
The patent divides the circuit elements into different substrates based on voltage requirements. High-voltage circuits (power supply circuits, protective circuits) are placed on a first substrate, while low-voltage circuits (control circuits, display driving circuits) are placed on a second substrate. This segmentation allows each substrate to be optimized for its specific voltage range, improving electrostatic discharge resistance while maintaining high device integration through the stacked configuration.
Solution Approach 2:
The patent introduces protective circuits as intermediary elements between the high-voltage power supply circuits and the low-voltage control circuits. These protective circuits act as mediators that protect the low-voltage circuits from voltage spikes and electrostatic discharge originating from the high-voltage side, thereby resolving the reliability issue while maintaining the benefits of multi-substrate integration.
2Ease of manufacture
If high-voltage circuits are integrated with low-voltage circuits on the same substrate, then manufacturing process is simplified, but electrostatic discharge resistance deteriorates
Solution Approach 1:
Instead of integrating all circuits on a single substrate, the patent segments the circuits into high-voltage and low-voltage groups and places them on separate substrates. This segmentation physically isolates the high-voltage circuits that are more susceptible to electrostatic discharge, thereby improving electrostatic discharge resistance while still using standard manufacturing processes for each substrate type.
Solution Approach 2:
The patent applies local quality by giving different substrates different voltage characteristics and protective measures. The first substrate is designed with high-voltage tolerance and includes protective circuits, while the second substrate is designed for low-voltage operation. This localized optimization allows each substrate to be manufactured using appropriate processes while improving overall electrostatic discharge resistance.
3Reliability
If protective circuits are added to safeguard unit circuits, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the protective circuits with the power supply circuits on the same first substrate. By combining these functions, the patent reduces the overall device complexity compared to having separate protective circuits for each unit circuit. The protective function is integrated into the power supply substrate, providing comprehensive protection while maintaining a manageable circuit structure.
Solution Approach 2:
The protective circuits on the first substrate serve multiple functions: they protect against electrostatic discharge, regulate voltage levels, and provide stable power supply to the second substrate. This multi-functionality reduces the need for additional dedicated protective circuits, thereby improving reliability without significantly increasing device complexity.
Data Source
AI summary
A light emitting device in which a light emitting element layer including a plurality of light emitting elements, a first substrate including at least a part of each of a plurality of unit circuits respectively connected to the plurality of light emitting elements, and a second substrate including at least a part of a control circuit configured to control the plurality of unit circuits are stacked. The device includes a first protective circuit arranged in the first substrate, and configured to protect the plurality of unit circuits, wherein a maximum voltage in the first substrate is higher than a maximum voltage in the second substrate.