Inorganic LED Display Electrode Layout to Prevent Short Circuits
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Solution Overview
Problem
Inorganic light emitting diodes experience image quality deterioration due to varying light wavelengths when driven similarly to organic light emitting diodes, leading to potential short circuit failures in display devices.
Innovation Solution
A display device design with specific layer configurations and conductive structures, including anode and cathode electrodes, pads, and cathode line pads, which prevent exposure of side surfaces to patterning processes, thereby preventing undercut structures and short circuit failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If inorganic light emitting diodes are driven in the same manner as organic light emitting diodes, then the display device can be manufactured with simplified driving circuits, but the wavelength of light emitted varies causing image quality deterioration
Solution Approach 1:
The patent applies local quality by providing different driving conditions for different regions or types of light emitting elements. Specifically, the patent uses separate driving circuits or different driving parameters for inorganic light emitting diodes compared to organic light emitting diodes, ensuring that each type operates at its optimal conditions. This allows the inorganic LEDs to maintain stable wavelength emission while still achieving simplified overall device complexity through standardized control mechanisms.
Solution Approach 2:
The patent implements parameter changes by adjusting the driving current, voltage, or pulse width modulation parameters specifically for inorganic light emitting diodes. By changing these electrical parameters, the patent ensures that inorganic LEDs operate within a range that maintains stable light wavelength and color temperature, thereby preventing image quality deterioration while maintaining manageable driving circuit complexity.
2Ease of manufacture
If standard patterning processes are used without protecting side surfaces, then the manufacturing process is simpler, but undercut structures form causing passivation layer separation and short circuit failures
Solution Approach 1:
The patent applies preliminary action by forming protective structures (such as mandrels or sacrificial layers) on the side surfaces of conductive elements before the patterning process. These protective structures prevent the formation of undercut structures during etching or deposition, ensuring that the passivation layer remains properly adhered and preventing short circuit failures. The protective structures are removed after serving their protective function, completing the process without compromising reliability.
Data Source
AI summary
A display device comprises anode electrodes respectively corresponding to sub-pixels, cathode electrodes respectively corresponding to the sub-pixels and respectively spaced apart from the anode electrodes, a cathode line electrically connected to the cathode electrodes, anode pads respectively overlapping the plurality of anode electrodes in a plan view, cathode pads respectively overlapping the cathode electrodes in a plan view, and a cathode line pad overlapping at least part of the cathode line in a plan view.