Tape Carrier Package Alignment Mark for LCD Panel Bonding
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Solution Overview
Problem
The existing methods for attaching tape carrier packages (TCPs) to liquid crystal display (LCD) panels face misalignment issues due to accumulated alignment errors and thermal expansion, leading to decreased display quality, reduced fabrication yield, and increased production costs as the size of LCDs increases.
Innovation Solution
The introduction of a third alignment mark at the central portion of the tape carrier package's output leads, along with corresponding alignment marks on the liquid crystal panel, ensures accurate alignment and reliable connection during the tape automated bonding (TAB) process, even when the TCP expands, by providing additional alignment margins and improved attachment reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only two alignment marks are used on the TCP, then the structure remains simple, but misalignment occurs due to accumulated alignment errors and thermal expansion
Solution Approach 1:
The patent introduces a third alignment mark at the central portion of the TCP's output leads as a preliminary measure to prevent misalignment. This additional alignment mark is positioned beforehand to compensate for accumulated alignment errors and thermal expansion that occur during the TAB process, ensuring accurate alignment between the TCP and the liquid crystal panel before bonding occurs.
2Measurement precision
If the TCP width is reduced to increase LCD resolution, then display quality improves, but alignment precision becomes more difficult to maintain
Solution Approach 1:
The patent addresses the alignment precision challenge by adding an alignment mark in the central dimension (third alignment mark) in addition to the existing two alignment marks. This dimensional addition provides an extra reference point that maintains alignment precision even when the TCP width is reduced for higher display resolution, as the central alignment mark serves as an additional constraint against misalignment.
3Productivity
If the TCP expands during bonding, then the bonding process completes, but misalignment occurs reducing fabrication yield
Solution Approach 1:
The patent implements beforehand cushioning by positioning the third alignment mark at the central portion of the output leads, which serves as a compensatory reference point. When the TCP expands during the bonding process, this pre-positioned central alignment mark provides a buffer against misalignment, allowing the bonding process to complete successfully while maintaining alignment stability and preventing yield reduction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution prevents misalignment, enhances display quality, increases fabrication yield, and reduces production costs by ensuring precise alignment and reliable attachment of TCPs to the liquid crystal panel, even with reduced TCP widths and increased resolution.
Implementation Method 1
first and second TCP alignment marks arranged on opposing sides of the plurality of output leads, and a third TCP alignment mark at a central portion of the plurality of output leads
Data Source
AI summary
A tape carrier package (TCP) includes a film, a plurality of output leads and a plurality of input leads on the film, the plurality of output leads and the plurality of input leads being disposed on different sides, first and second TCP alignment marks arranged on opposing sides of the plurality of output leads, and a third TCP alignment mark at a central portion of the plurality of output leads.