Polygonal Chiplets for Flexible Display Substrates
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Solution Overview
Problem
Existing display devices face limitations in flexibility and performance due to the use of thin-film transistors, which are prone to cracking and non-uniformity, and prior alternative pixel-control devices are not readily flexible.
Innovation Solution
The use of distributed, independent chiplets with crystalline substrates and complex shapes like plus signs, hexagonal, or octagonal configurations, integrated with a flexible substrate and cover, to improve flexibility and performance by reducing the size and increasing the number of connection pads without increasing the total area, allowing for better bending and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thin-film transistors are used for pixel control, then device complexity is reduced and ease of manufacture is improved, but flexibility deteriorates due to cracking and non-uniformity
Solution Approach 1:
The control circuit is segmented into multiple independent chiplets distributed across the substrate rather than using a continuous thin-film transistor layer. Each chiplet is a discrete component that can be independently manufactured and positioned, eliminating the cracking and non-uniformity issues inherent in thin-film transistor structures while maintaining ease of manufacture through modular assembly.
2Reliability
If more connection pads are added to chiplets, then electrical performance and connectivity are improved, but device complexity and area increase
Solution Approach 1:
Multiple connection pads are merged into a single integrated connection structure on each chiplet. The connection pad is designed as a unified element that provides multiple electrical connections simultaneously, reducing the number of separate pads needed while maintaining comprehensive electrical connectivity and performance.
Solution Approach 2:
Each connection pad is designed to serve multiple functions: it provides electrical connection, mechanical anchoring, and stress distribution. This multi-functionality reduces the need for separate specialized components, thereby reducing overall device complexity while maintaining electrical performance.
3Reliability
If chiplet size is reduced to increase number of connection pads, then flexibility is improved, but manufacturing precision requirements increase
Solution Approach 1:
The chiplets are pre-assembled and tested on smaller substrate sections before final integration into the complete display device. This preliminary assembly allows for verification of connection pad alignment and electrical connectivity at reduced scale, ensuring that manufacturing precision requirements are met without requiring extremely tight tolerances during final assembly.
Data Source
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AI summary
A display device 5 includes a substrate 10 having a display area 11; an adhesion layer 18 formed on the substrate surface; a plurality of chiplets 20 adhered to the substrate 10 and distributed within the display area 11, each chiplet 30 having one or more connection pads 24, wherein each chiplet has more than four sides; a plurality of pixels 15 formed over the adhesion layer 13 in the display area 11, each pixel 15 having a bottom electrode 12 electrically connected to a connection pad 24 of one chiplet 20, one or more layers of light-emitting material 14 formed over the bottom electrode 12, and a top electrode 16 formed over the one or more layers of light-emitting material 14; and a cover 70 located over the top electrode 16 and adhered to the substrate 10.