Tiled Display Pad Structure for Inspection Speed and Seam Control
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Solution Overview
Problem
Large-sized display devices face increased defective rates of light emitting elements, leading to decreased productivity and reliability, and the seams between connected display devices cause a sense of discontinuity, reducing image immersion.
Innovation Solution
A display device design with inspection pad parts and pad parts of varying widths, allowing for efficient inspection and reduced bonding material use, and a tiled display device configuration that minimizes non-display areas to prevent seam recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If display devices are manufactured in a great size, then the screen size is increased, but the defective rate of light emitting elements increases and productivity decreases
Solution Approach 1:
The display device is divided into multiple sub-display devices arranged in a matrix pattern on a single substrate. Each sub-display device functions as an independent display unit with its own pixel array, allowing the overall display to achieve a large screen size while maintaining manageable manufacturing complexity and acceptable yield rates for each individual sub-unit.
2Area of stationary object
If display devices are manufactured in a great size, then the screen size is increased, but the defective rate of light emitting elements increases and reliability decreases
Solution Approach 1:
By segmenting the display into multiple independent sub-display devices, the reliability risk is distributed across units. If defects occur in one sub-display device, other sub-display devices can continue to function, maintaining overall system reliability while achieving a large total screen area.
3Area of stationary object
If multiple display devices are connected to form a tiled display, then the screen size is increased, but boundary portions create a sense of discontinuity and image immersion decreases
Solution Approach 1:
Multiple sub-display devices are integrated onto a single substrate and electrically connected through conductive structures formed within the substrate. This merging approach creates a unified display structure where the sub-display devices function as one continuous display surface, eliminating the visual discontinuity that would result from physically separate connected devices.
Solution Approach 2:
The connection structures between sub-display devices are positioned in the vertical dimension (within the substrate thickness) rather than in the horizontal plane. This allows electrical connections to pass through the substrate without creating visible boundary lines on the display surface, maintaining image continuity while enabling multiple sub-displays to be electrically connected.
4Productivity
If inspection pad parts with smaller width are used, then inspection efficiency is improved and defective products are quickly identified, but manufacturing precision requirements increase
Solution Approach 1:
Different regions of the substrate are assigned different functions with appropriate structural characteristics. Inspection pad parts are designed with smaller dimensions optimized for electrical testing, while data pad parts have larger dimensions for bonding connections. This local differentiation allows inspection pad parts to be optimized for inspection efficiency while the overall design accounts for manufacturing capabilities through proper spatial distribution and functional specialization.
Data Source
AI summary
A display device includes a first substrate including a first contact hole, a first barrier insulating layer disposed on the first substrate and including second contact holes, pad parts inserted into some contact holes of the second contact holes, inspection pad parts inserted into other contact holes of the second contact holes, fan-out lines formed of a first metal layer on the first barrier insulating layer and being integral with the pad parts, a display layer disposed on the fan-out lines, and a flexible film disposed below the first substrate and inserted into the first contact hole to be electrically connected to the pad parts. A width of each of the pad parts is greater than a width of each of the second contact holes, and a width of each of the inspection pad parts is smaller than the width of each of the second contact holes.