LED Display Electrode Layout for Transfer Misalignment Tolerance
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Solution Overview
Problem
The production of light-emitting display devices using LED elements is hindered by high substrate costs and difficulties in accurately transferring LED elements from semiconductor substrates to display device substrates, leading to increased defect rates and production costs.
Innovation Solution
A light-emitting device with an inverted tapered structure between its n-type and p-type electrodes, which minimizes defects in electrode connection even if the device is misaligned during transfer, and a display device utilizing this light-emitting device to improve processing stability and reduce defect rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LED elements are transferred from semiconductor substrates to display device substrates, then light-emitting display devices can be produced, but transfer accuracy decreases and defect rates increase
Solution Approach 1:
The invention segments the electrode connection structure into multiple functional layers: the light-emitting device with its native electrodes, an intermediate connection structure with connection electrodes, and the display device substrate with pixel electrodes. This segmentation allows each component to be optimized independently and facilitates accurate alignment during transfer processes, thereby improving transfer accuracy while maintaining productivity.
Solution Approach 2:
The invention implements preliminary action by pre-forming connection electrodes on the display device substrate before transferring the light-emitting devices. These connection electrodes are positioned in advance to match the expected locations of the light-emitting device electrodes, enabling accurate alignment and connection without requiring high-precision transfer of the light-emitting devices themselves, thus resolving the contradiction between productivity and manufacturing precision.
2Ease of manufacture
If substrate costs are reduced, then production costs decrease, but manufacturing complexity increases
Solution Approach 1:
The invention applies universality by designing a manufacturing approach where the connection structure serves multiple functions: it provides electrical connection between light-emitting devices and pixel electrodes, enables alignment reference during transfer, and facilitates module assembly. This multi-functional design simplifies the overall manufacturing process despite using cost-effective substrates, as the same structural elements fulfill multiple requirements without adding extra complexity.
Solution Approach 2:
The connection structure acts as an intermediary element between the light-emitting devices and the display device substrate. This intermediary layer simplifies manufacturing by providing a buffer zone for alignment tolerance and a standardized interface for connection, allowing the use of lower-cost substrates without compromising the overall manufacturing complexity or connection reliability.
3Reliability
If electrode connection stability is improved, then device reliability increases, but manufacturing precision requirements increase
Solution Approach 1:
The invention implements beforehand cushioning by designing the connection structure with built-in alignment tolerance and compensation mechanisms. The connection electrodes are formed with dimensions and positioning that accommodate expected transfer variations, providing a cushion against misalignment. This approach ensures stable electrode connection and high device reliability without requiring extremely high manufacturing precision in the transfer process.
Data Source
AI summary
A display device includes a substrate; a thin-film transistor including an active area, a source electrode, and a drain electrode disposed on the substrate; a passivation layer disposed on the thin-film transistor; a light-emitting device disposed on the passivation layer and including a first electrode, a second electrode, and a structure disposed between the first electrode and the second electrode; a planarization layer disposed on the passivation layer to cover a side surface of the light-emitting device; a pixel electrode electrically connected to the drain electrode of the thin-film transistor through a first contact hole in the passivation layer and the planarization layer, and electrically connected to the first electrode through a second contact hole in the planarization layer; and a common electrode electrically connected to the second electrode through a third contact hole formed in the planarization layer.