NTC Sensor Miniaturization via Segmented Parallel Wire Design
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Solution Overview
Problem
Conventional NTC thermistor temperature sensors with plastic coatings face challenges in miniaturization due to their size, which limits their integration into small electronic assemblies, and existing manufacturing methods do not allow for precise resistance tolerance and efficient thermal conductivity.
Innovation Solution
The NTC sensor design features a chip with two parallel wires, where the chip is positioned at contact points on the wires, forming mechanical and electrical connections using minimal solder or adhesive, allowing for a compact design with precise resistance control and thermal conductivity, and is encased in a polymer material for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional assembly and coating technologies are used to manufacture NTC thermistor temperature sensors with plastic coating, then the sensors can be produced with standard manufacturing processes, but the sensor dimensions are too large for integration into small electronic assemblies
Solution Approach 1:
The sensor is divided into functionally independent components: an NTC thermistor element, connecting wires with contact points, and a plastic housing. These segments can be manufactured separately using optimized processes and then assembled, allowing each component to be minimized in size independently while maintaining overall manufacturability
Solution Approach 2:
The connecting wires are arranged parallel to each other in a straight line configuration, changing the spatial arrangement from conventional radial or orthogonal layouts. This dimensional optimization allows the sensor head to achieve a maximum lateral dimension that is equal to or less than the sum of the lateral dimensions of the chip and wires, enabling insertion through small channels in compact electronic assemblies
2Volume of moving object
If the sensor head dimensions are minimized for compact assembly integration, then the sensor can be inserted through small insertion channels, but the connection strength between chip and wires may be compromised
Solution Approach 1:
Contact points are formed on the wires in advance during wire preparation, creating pre-formed connection interfaces. The chip is then positioned and connected to these pre-prepared contact points using minimal solder or adhesive, ensuring strong connections are established before final assembly, thereby maintaining connection strength while minimizing overall sensor head dimensions
Solution Approach 2:
A minimal amount of solder or conductive adhesive is used as an intermediary material to create strong mechanical and electrical connections between the chip and the wire contact points. This intermediary substance enables reliable bonding in the minimized sensor head configuration without requiring large connection areas or excessive material
3Volume of moving object
If minimal solder or adhesive is used for contacting the chip to the wires, then the sensor head dimensions are reduced, but the manufacturing precision required increases
Solution Approach 1:
Contact points are pre-formed on the wires at specific locations before chip attachment. The chip is designed with electrode positions that correspond to these pre-formed contact points, establishing predetermined connection locations. This preliminary preparation of contact interfaces significantly reduces the manufacturing precision required during final assembly, as the components are designed to mate at specific, pre-determined locations rather than requiring high-precision alignment during bonding
Solution Approach 2:
The wire contact points are designed with specific geometric parameters (such as flattened ends or exposed conductive sections) that change the physical characteristics of the connection interface. These parameter changes in the wire structure create self-aligning features that reduce the precision requirements for chip-to-wire bonding, enabling minimal solder or adhesive application while maintaining connection reliability
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 design enables the NTC sensor to be easily inserted into small assemblies with reduced space and cost, maintaining high precision and strength in connections while minimizing the sensor head dimensions, allowing for precise temperature measurement and resistance control.
Implementation Method 1
The electrical resistance of an NTC thermistor ceramic changes with changing temperatures. In particular, the resistance of the NTC thermistor decreases with increasing temperatures. NTC stands for Negative Temperature Coefficient.
Implementation Method 2
The connection or contact between the chip and the wires is made either by soldering or by applying a conductive adhesive.
Data Source
AI summary
In an embodiment a NTC sensor include a chip, two parallel wires, each wire having contact points, and contact-connections between the chip and the contact points of each of the wires, wherein a maximum lateral dimension of the NTC sensor in any direction perpendicular to a direction of extension of the wires is equal to or less than a sum of the lateral dimensions of the chip and the wires.