Capacitive Sensor 3D Wiring Reduces Dead Region
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Solution Overview
Problem
Conventional capacitive sensors have a dead region where no load can be detected, leading to increased size and weight, limited flexibility in design, and potential delamination or fracture due to poor flexibility of insulating layers, which restricts their use in applications requiring reduced size and weight.
Innovation Solution
A capacitive sensor with a three-dimensional wiring structure using an insulating layer with high elongation at break and low tension set, allowing the electrode and jumper wiring layers to be arranged non-planarly, reducing the dead region and enhancing flexibility and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wiring layers are formed on the same plane as electrode layers in conventional capacitive sensors, then electrical connection is simplified, but dead regions increase leading to larger sensor size and weight
Solution Approach 1:
The patent transitions from a planar two-dimensional wiring arrangement to a three-dimensional stacked arrangement. The jumper wiring layer is positioned on the opposite side of the insulating layer from the electrode layer, creating vertical separation. This dimensional change eliminates the need for peripheral dead regions, allowing the sensor active area to extend to the edges and reducing overall sensor size and weight.
2Reliability
If rigid insulating layers are used in three-dimensional wiring structures, then electrical insulation is improved, but flexibility decreases causing delamination or fracture under repeated extension and contraction
Solution Approach 1:
The patent changes the physical parameters of the insulating layer by selecting materials with high elongation at break (60% or more) and low tension set (less than 5%). This parameter change allows the insulating layer to maintain electrical insulation while simultaneously providing the flexibility needed to withstand repeated extension and contraction without delamination or fracture.
Solution Approach 2:
The patent employs composite material selection for the insulating layer, combining polymers such as polyurethane, polyester elastomer, or silicone rubber that inherently possess both insulating properties and high elasticity. This composite approach ensures both electrical insulation and mechanical flexibility are achieved together.
3Ease of manufacture
If conventional insulating layers with poor flexibility are used, then manufacturing is simplified, but durability decreases due to delamination or fracture from repeated deformation
Solution Approach 1:
The patent specifies critical material parameters for the insulating layer: elongation at break of 60% or more and tension set of less than 5%. These parameter changes ensure the insulating layer can endure repeated deformation cycles, significantly improving sensor durability while remaining compatible with conventional manufacturing processes like screen printing.
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
The solution results in a more compact, lightweight, and flexible capacitive sensor capable of detecting load distribution with improved durability and reduced risk of delamination, suitable for applications in limited spaces.
Implementation Method 1
The insulating layer has an elongation at break of 60% or more and a tension set of less than 5%
Implementation Method 2
Capacitance of the detection units is thus increased. The capacitive sensor 9 can thus measure load distribution based on a change in capacitance which is caused by a change in distance between the electrodes
Implementation Method 3
a dielectric layer 2 made of a material having a relatively high dielectric constant
Data Source
AI summary
Provided is a flexible, durable capacitive sensor that achieves high flexibility in designing wiring arrangement. A capacitive sensor includes a dielectric layer and a plurality of electrode units placed on both sides of the dielectric layer in the front-back direction. The electrode unit includes an insulating layer having through holes extending therethrough in the front-rear direction, electrode layers placed on one side of the insulating layer in the front-back direction, and jumper wiring layers placed on the other side of the insulating layer in the front-back direction and electrically connected to the electrode layers through the through holes. The insulating layer has an elongation at break of 60% or more, a tension set of less than 5%, and a volume resistivity of 1.0×1010 Ω·cm or more.