Flexible Circuit Pad Layout for Display Panel Alignment Correction
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Solution Overview
Problem
The existing display devices face challenges in ensuring reliable connections between flexible circuit films and display panels due to misalignment caused by process errors, such as contraction or expansion of the flexible circuit film during manufacturing, leading to inconsistencies in the pitch between connection pads and panel pads.
Innovation Solution
Incorporating measurement pads and dummy pads on the flexible circuit film, which are inclined with respect to a reference line, to accurately measure and correct the pitch, ensuring proper alignment with the display panel's pads by using these pads to determine the Y-axis correction value, thereby minimizing misalignment and enhancing connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flexible circuit film is used to electrically connect the display panel, then the connection between the flexible circuit film and the display panel is established, but misalignment occurs between the connection pads and the display pads due to process errors such as contraction or expansion of the flexible circuit film
Solution Approach 1:
The patent applies preliminary action by pre-defining measurement pads and dummy pads on the flexible circuit film before the bonding process. These pads are used to measure the actual pitch of the connection pads and calculate correction values in advance, allowing the alignment issue to be compensated for before the actual connection is made. This prevents misalignment caused by process errors rather than attempting to fix it after the fact.
Solution Approach 2:
The patent employs parameter changes by introducing inclination angles for the measurement pads and dummy pads relative to the reference line. By setting specific inclination angles (e.g., 30 degrees), the pads can measure pitch variations more accurately and compensate for the contraction or expansion of the flexible circuit film. This changes the geometric parameters of the pad layout to achieve better alignment tolerance.
2Measurement precision
If measurement pads and dummy pads are added to the flexible circuit film, then the pitch measurement and alignment correction capability is improved, but the structure of the flexible circuit film becomes more complex
Solution Approach 1:
The measurement pads and dummy pads serve multiple functions: they are used for measuring the pitch of connection pads, calculating correction values, and compensating for process errors. By making these pads multi-functional, the patent reduces the need for separate dedicated measurement structures, thereby minimizing the increase in overall complexity while achieving precise pitch measurement.
Solution Approach 2:
The patent uses a limited number of measurement pads (typically two) and dummy pads positioned strategically around the connection pads. Rather than adding comprehensive measurement structures across the entire flexible circuit film, only the minimum necessary pads are added to achieve accurate pitch measurement and correction, thus avoiding excessive complexity.
Data Source
AI summary
A display device is provided and includes a display panel including a display area that displays an image and a pad area disposed at least at a side of the display area, and a flexible circuit film electrically connected to the pad area. The flexible circuit film includes connection pads, a first measurement pad, and a second measurement pad. The connection pads are arrayed in a first direction and inclined with respect to a reference line extending in a second direction different from the first direction, the first measurement pad is disposed adjacent to a first side of the connection pads, and the second measurement pad is disposed adjacent to a second side of the connection pads. The connection pads are between the first measurement pad and the second measurement pad.