Capacitive Sensor Element Redundant Conductive Strips
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Solution Overview
Problem
The existing capacitive sensor elements face challenges in achieving accurate alignment of conductive layers during assembly, which is costly and limits mass production due to stringent tolerance requirements for reliable signal reading, especially in touch screens like smartphones and iPads.
Innovation Solution
The capacitive sensor element design features conductive strips and connections on a single plane, with redundant stripe electrodes that can tolerate registration inaccuracies, allowing for greater positioning flexibility and cost-effective mass production by using a roll-to-roll printing process with transparent conductive materials and dielectric insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrically conductive layers are laid accurately one on top of the other with tolerance less than 200 μm, then the connections reliably contact the plugs for accurate signal reading, but the assembly process becomes expensive and difficult for mass production
Solution Approach 1:
The patent changes the critical parameter from layer alignment position to conductive strip spacing. By designing the conductive strips with specific spacing and dimensions, the system becomes tolerant to positional variations during assembly, allowing larger tolerance limits while maintaining reliable signal reading.
Solution Approach 2:
The patent applies different properties to different parts of the conductive layers. The connections are positioned in a plane with the insulating layer not separating the layers over the whole surface, creating local variations in structure that enable tolerance to registration inaccuracies while maintaining reliable electrical contacts.
2Stability of the object's composition
If the insulating layer separates the two electrically conductive layers over the whole surface, then galvanic separation is ensured, but the connections cannot be positioned in one plane for tolerance compensation
Solution Approach 1:
The patent segments the insulating layer's coverage, allowing it to separate the conductive layers in most areas while leaving specific regions exposed. This segmentation enables connections to lie in one plane for tolerance compensation while maintaining galvanic separation where the insulating layer is present.
Solution Approach 2:
The insulating layer acts as an intermediary that is selectively applied or removed in specific regions. It provides galvanic separation where needed while allowing direct contact or planar alignment of connections in other regions, mediating between the requirements for electrical isolation and positioning flexibility.
Data Source
AI summary
The invention relates to a capacitive sensor element with a plurality of sensor fields, as they correspond for example to the arrangement on a touch screen. This capacitive sensor element comprises at least one multilayer body made up of two structured electrically conductive layers and an insulating layer in between. The invention provides a layout with redundant conductive strips for an arrangement of crossing conductive strips, through which the requirement for register accuracy in the two-layer lamination of layer electrodes is reduced, in particular with respect to connecting the connections to the plugs in the edge area of a module using a corresponding sensor element.