TAB Tape Design for Curved LCD Bonding Stability
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Solution Overview
Problem
Conventional tape automated bonding (TAB) tapes on curved liquid crystal display (LCD) panels face issues with falling off due to tensile forces, leading to potential failure of the LCD panel.
Innovation Solution
Designing TAB tapes with specific size ratios and dimensions, including a longitudinal length of the driving chip less than or equal to half of the TAB tape's length excluding outer leads, and a transverse length of the driving chip less than or equal to half of the TAB tape's transverse length, to distribute the tensile force effectively, calculated through mathematical simulations and verified by experiments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If TAB tape is used on curved LCD panel, then driving chip can be mounted to enlarge display area, but tensile force causes bonded tape to fall off
Solution Approach 1:
The patent applies parameter changes by optimizing the length-to-width ratio of the TAB tape and adjusting the bonding area parameters. Specifically, the tape length is set to be 4 times or more the distance from the bending point to the bonding end, and the bonding area is designed to be 0.5 times or more the chip area, ensuring reliable bonding while maintaining the curved display structure.
Solution Approach 2:
The patent addresses the bonding stability issue by introducing dimensional considerations in the tape geometry. By specifying that the tape length should be at least 4 times the distance from the bending point to the bonding end, and the bonding area should be at least half the chip area, the design distributes tensile forces across multiple dimensions, preventing tape detachment on curved surfaces.
2Shape
If TAB tape is bent in two directions on curved panel, then curved display shape is achieved, but great tensile force acts on bonding surfaces
Solution Approach 1:
The patent resolves the force issue by changing geometric parameters of the TAB tape. The length is designed to be 4 times or more the distance from the bending point to the bonding end, and the bonding area is set to 0.5 times or more the chip area. These parameter adjustments distribute the tensile force generated by dual-directional bending, preventing bonding surface failure while maintaining the desired curved shape.
3Reliability
If bonding area is increased to prevent tape from falling off, then bonding stability improves, but device complexity increases
Solution Approach 1:
The patent achieves improved bonding stability without excessive complexity by optimizing specific parameters: the tape length is set to 4 times or more the distance from the bending point to the bonding end, and the bonding area is designed to be 0.5 times or more the chip area. This parameter-based approach provides reliable bonding through mathematical relationships rather than complex structural designs.
Data Source
AI summary
Provided is a method of manufacturing a curved display device, wherein a tape automated bonding (TAB) tape, which includes a base film, a driving chip formed at an upper portion of the base film, a plurality of one-side outer leads formed to bond an output terminal of the driving chip and a terminal of a liquid crystal display (LCD) substrate by an outer lead bonding (OLB) method, and a plurality of the other-side outer leads formed to bond an input terminal of the driving chip and a terminal of a printed circuit board, is designed so that from the end of the OLB bonding part to the part at which the film begins to bend is greater than or equal to the longitudinal length (E) of the driving chip ((4F−D/2)≥E).