Display Device Spacer Design Prevents Test Pad Short Circuits
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Solution Overview
Problem
Display devices face issues with short circuits during manufacturing testing due to damage from probing pins, leading to degradation of display quality.
Innovation Solution
The implementation of a display device design that includes spacers with varying heights and materials, specifically a first spacer supporting both substrates, a second spacer with reduced height not contacting the upper substrate, and a third spacer overlapping the test line and pad, preventing contact with the common electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a test apparatus is used to perform tests on circuit wiring during manufacturing, then manufacturing precision is improved, but the test apparatus may be damaged by probing pins causing short circuits between the test apparatus and common electrode
Solution Approach 1:
A third spacer is introduced as an intermediary protective element between the test line/test pad portion and the common electrode. This spacer acts as a physical barrier that prevents direct contact between the probing pin and the common electrode during testing, thereby eliminating the short circuit risk while allowing the test apparatus to function normally.
Solution Approach 2:
The solution adds a vertical dimension (height) to the spacer structure to solve the horizontal plane problem. By making the third spacer's height less than the cell gap, it creates a vertical clearance that prevents the probing pin from reaching the common electrode, thus solving the short circuit issue through dimensional design.
2Reliability
If spacers are used to maintain cell gap and prevent short circuits, then reliability is improved, but device complexity increases due to multiple spacers with different heights and materials
Solution Approach 1:
Different spacers are designed with different heights and material properties according to their specific functional requirements. The first spacer has height equal to the cell gap for full support, the second spacer has reduced height for partial support, and the third spacer has minimal height for protection only. This localized optimization allows each spacer to perform its specific function efficiently without unnecessary complexity.
Solution Approach 2:
The spacers are designed to serve multiple functions: the first spacer provides both support and protection, the second spacer provides support with reduced height, and the third spacer provides protection while allowing test access. This multi-functionality reduces the need for additional separate components, thereby managing complexity while maintaining reliability.
3Reliability
If the third spacer has height less than the cell gap to prevent contact with the second substrate, then short circuit prevention is improved, but the spacer must be precisely controlled in height
Solution Approach 1:
The third spacer is designed with a height that is intentionally less than the full cell gap, providing just enough protection to prevent short circuits without requiring precise control to match the exact cell gap dimension. This partial action approach simplifies manufacturing by allowing a range of acceptable heights rather than requiring exact precision.
Data Source
AI summary
A display device is capable of substantially preventing a short circuit between a common electrode and a test pad, the display device including: a first substrate and a second substrate; a thin film transistor disposed on the first substrate; a gate line and a data line connected to the thin film transistor; a test pad portion connected to the data line; a test line connecting the test pad portion and the data line; and a spacer disposed on the first substrate. The spacer includes: a first spacer disposed on the display area and supporting the first substrate and the second substrate; a second spacer disposed on the display area, the second spacer having a less height than a height of the first spacer; and a third spacer overlapping the test line and the test pad portion disposed on the non-display area, the third spacer not contacting the second substrate.