Touch Panel Warping Prevention via Nonparallel Resin Flow
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Solution Overview
Problem
Touch panels used in high-temperature environments, such as car navigation systems, experience warping and nonuniform sensitivity due to parallel resin flowing directions of the plastic cover and film sensor, leading to appearance and functional issues.
Innovation Solution
Laminating the plastic cover and film sensor with resin flowing directions that are nonparallel, preferably at right angles, to prevent warping under high-temperature conditions, ensuring the touch panel and casing remain joined.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the resin flowing direction of the film sensor and the resin flowing direction of the plastic cover are parallel to each other, then the manufacturing process is simplified and alignment is easier, but the input device warps greatly under high-temperature environment
Solution Approach 1:
The patent applies asymmetry by deliberately setting the resin flowing directions of the plastic cover and film sensor at nonparallel angles (specifically 45-135 degrees relative to each other). This asymmetric arrangement prevents the synchronized thermal expansion that occurs with parallel alignment, thereby suppressing warping under high-temperature conditions while maintaining manufacturing feasibility.
Solution Approach 2:
The patent changes the critical parameter of resin flowing direction angle from the conventional parallel (0 degrees) configuration to a nonparallel configuration (45-135 degrees). This parameter change fundamentally alters the thermal response characteristics of the laminated structure, preventing warping without significantly complicating the manufacturing process.
2Stability of the object's composition
If the resin flowing direction of the film sensor and the resin flowing direction of the plastic cover are nonparallel to each other, then warping under high-temperature environment is suppressed, but the manufacturing complexity increases
Solution Approach 1:
The patent applies asymmetry by deliberately setting the resin flowing directions of the plastic cover and film sensor at nonparallel angles (specifically 45-135 degrees relative to each other). This asymmetric arrangement prevents the synchronized thermal expansion that occurs with parallel alignment, thereby suppressing warping under high-temperature conditions while maintaining manufacturing feasibility.
Solution Approach 2:
The patent changes the critical parameter of resin flowing direction angle from the conventional parallel (0 degrees) configuration to a nonparallel configuration (45-135 degrees). This parameter change fundamentally alters the thermal response characteristics of the laminated structure, preventing warping without significantly complicating the manufacturing process.
3Stability of the object's composition
If film base materials are laminated with crossing film forming directions, then anisotropy of the film base materials is reduced, but the relationship with other members is not optimized for high-temperature stability
Solution Approach 1:
The patent changes the critical parameter of resin flowing direction angle from the conventional parallel (0 degrees) configuration to a nonparallel configuration (45-135 degrees). This parameter change fundamentally alters the thermal response characteristics of the laminated structure, preventing warping without significantly complicating the manufacturing process.
Solution Approach 2:
The patent applies local quality by optimizing the resin flowing direction relationship specifically at the interface between the film sensor and plastic cover. This localized optimization of directional alignment prevents warping at this critical junction, thereby ensuring overall high-temperature reliability of the input device.
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 configuration effectively suppresses warping and maintains the appearance and function of the touch panel, preventing peeling and nonuniform sensitivity distribution, even in high-temperature environments.
Implementation Method 1
The touch panels described in PTLs 1 and 2 have a configuration in which the film base material forming directions (lengthwise directions) cross at right angles to reduce the anisotropy of the film base materials. However, in these touch panels, the relationship between the film forming directions of the plurality of film base materials composed of the same material and having the same thickness is specified, but the directions of arrangement of the film base materials in relation to other members are not studied. Furthermore, PTLs 1 and 2 do not describe problems in the case where the touch panels are used under a high-temperature environment.
Implementation Method 2
PTLs 1 and 2 describe a touch panel made of a film base material, which is less prone to thermal deformation during manufacturing. The touch panel has a configuration in which two film base materials with a transparent conductive layer composed of the same material and having the same thickness are laminated so that the film forming directions form 90 degrees.
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3~4
AI summary
A touch panel 1 is configured such that a plastic cover 11 and a film sensor 12 are laminated so that the resin flowing direction MD1 of the plastic cover 11 and the resin flowing direction MD2 of the film sensor 12 are not parallel to each other in plan view in the laminating direction (Z1-Z2). The touch panel 1 is prevented from being degraded in design and becoming nonuniform in sensitivity because of the occurrence of warping, thereby maintaining its appearance and function well under a high-temperature environment.