Gas Sensor Electrode Pad Arrangement for Short-Circuit Prevention
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Solution Overview
Problem
Conventional gas sensors with multiple electrode pads on a single surface face challenges in ensuring adequate spacing, leading to short-circuits and increased size due to overlapping connections, which hinders length reduction and reliability of electric connections.
Innovation Solution
A sensor element design featuring three electrode pads, where two are arranged in a widthwise direction and a single pad on the tip or rear end is positioned to avoid overlap, with a connection portion connected to a through hole conductor adjacent to its side surface, ensuring adequate spacing and reducing overall length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If three electrode pads are arranged in widthwise direction on one surface, then connection terminals can be connected to electrode pads, but distances between electrode pads cannot be sufficiently ensured, causing short-circuits
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of electrode pads on the surface to a three-dimensional configuration using through-hole conductors that extend through the thickness direction of the sensor element. This allows connection portions to be positioned on the rear surface while maintaining adequate spacing on the front surface, effectively adding a depth dimension to resolve the spacing conflict.
Solution Approach 2:
The through-hole conductors are embedded within the sensor element body, with connection portions nested on the rear surface. This nesting approach allows multiple connection points to be compactly arranged without increasing the footprint on the front surface, maintaining both connectivity and spacing.
2Ease of operation
If electrode pads are arranged in longitudinal direction along axis O, then connection can be established, but entire length Lx of electrode pads becomes long, preventing length reduction of sensor element
Solution Approach 1:
The invention moves the connection portions from the front surface to the rear surface of the sensor element by utilizing through-hole conductors extending in the thickness direction. This dimensional transition allows the electrode pads to be positioned closer together on the front surface without increasing the longitudinal length, as the connections are established through the depth of the element rather than along its length.
3Ease of operation
If connection portion is formed on through hole conductor, then electrode connection is enabled, but stepped portion is generated making it difficult for connection terminal to be surely abutted, reducing connection reliability
Solution Approach 1:
The patent introduces a planarization layer as an intermediary between the stepped connection portion and the connection terminal. This intermediate layer fills the stepped portion to create a flat surface, ensuring reliable abutment of the connection terminal while maintaining the benefits of the through-hole conductor configuration.
4Length of moving object
If distance between through hole conductor and electrode pad is reduced to decrease length Lx, then compactness is improved, but conductive paste may short-circuit with electrode pad
Solution Approach 1:
The invention repositions the connection portions to the rear surface of the sensor element through through-hole conductors, utilizing the thickness dimension to separate the connection areas. This allows the front surface electrode pads to be positioned closer together without risking short-circuits, as the conductive paths are separated in the depth direction rather than requiring large lateral spacing.
Data Source
AI summary
A sensor element includes: three electrode pads provided on the first main surface, and electrically connected to a connection terminal, the three electrode pads including; a pad group including two electrode pads which are arranged in a widthwise direction of the sensor element, and a single pad which is not overlapped with the pad group when viewed in a widthwise direction, the single pad including a main body portion which has a width greater than a clearance between the two electrode pads of the pad group, which is electrically connected to the connection terminal, and a connection portion which is connected to a conductor formed within a through hole extending within the sensor element in a thickness direction, and which is adjacent to a side surface of the main body portion.