Display Driver IC Pad Segmentation for Reliable Contact Testing
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Solution Overview
Problem
In display devices, electrical contact defects between components can reduce reliability, and existing test methods for detecting these defects often compromise test reliability due to insufficient contact between test pins and pads.
Innovation Solution
The display device incorporates a driver integrated circuit with pads divided into non-overlapping first and second areas, where the second area is larger and dedicated for test pin contact, and includes a dam structure to prevent solder interference, ensuring reliable contact with test pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pad area is made larger to improve contact reliability with test pins, then test reliability is improved, but the overall device area increases
Solution Approach 1:
The pad is divided into two distinct areas: a first pad area for contact with the contact pin of the driving chip, and a second pad area for contact with the test pin of the test device. This segmentation allows each area to be optimized for its specific function without compromising the other, resolving the contradiction between needing a large contact area for reliability and limiting the overall pad footprint.
Solution Approach 2:
Different regions of the pad are assigned different functions with different quality requirements. The first pad area is optimized for bonding with the driving chip contact pin, while the second pad area is optimized for testing with test pins. This local differentiation allows the pad to provide reliable contact for both purposes without requiring a uniformly large area.
2Manufacturing precision
If the contact pin width is reduced to improve alignment precision, then alignment precision is improved, but contact reliability with test pins deteriorates
Solution Approach 1:
By segmenting the pad into first and second areas, the contact pin can have a reduced width for precise alignment with the driving chip, while the second pad area provides a separate, adequately sized contact zone for the test pin. This eliminates the trade-off where reducing contact pin width would compromise test contact reliability.
Solution Approach 2:
The second pad area acts as an intermediary between the contact pin and the test pin. It provides a reliable contact interface for the test pin that is spatially separated from the contact pin, allowing the contact pin to be narrow for precision while maintaining reliable test contact through the intermediary second pad area.
3Ease of manufacture
If the pad structure is simplified to ease manufacturing, then ease of manufacture is improved, but test reliability deteriorates due to insufficient contact area
Solution Approach 1:
The pad is segmented into two functionally distinct areas that can be manufactured together as a single integrated structure. This segmentation provides adequate contact areas for both the driving chip contact pin and the test pin, maintaining test reliability while avoiding the need for complex separate structures.
Solution Approach 2:
The pad structure serves multiple functions: it provides contact for the driving chip through the first pad area and provides contact for testing through the second pad area. This multi-functionality allows a single pad structure to address both manufacturing simplicity and test reliability requirements without needing separate components.
Data Source
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AI summary
A display device includes a display panel including a plurality of pixels disposed in a display area, and a driver integrated circuit electrically connected to the plurality of pixels, where the driver integrated circuit includes a plurality of pads spaced apart from each other, and a driving chip including a plurality of contact pins electrically contacting the plurality of pads, respectively. Each of the plurality of pads includes a first pad area electrically contacting a corresponding contact pin among the plurality of contact pins, and a second pad area partitioned from the first pad area and not overlapping the corresponding contact pin in a plan view.