Magnetic Sensor Gap Control via Selective Surface Grinding
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Solution Overview
Problem
Magnetic sensors face challenges in maintaining small gaps between the sensor chip and magnetism collecting member due to low machining accuracy, affecting detection sensitivity and increasing manufacturing costs when trying to control gap size and variability.
Innovation Solution
The magnetic sensor design includes selectively grinding or polishing only the first and second surfaces of the magnetism collecting member to enhance flatness, while keeping other surfaces unmodified, allowing for precise gap control without unnecessary cost increases, and using adhesives on specific surfaces for fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If all surfaces of the magnetism collecting member are ground or polished to enhance flatness, then the gap between the element formation surface and the magnetism collecting member is reduced, but the manufacturing cost increases
Solution Approach 1:
The patent applies grinding or polishing only to the first surface (contact surface with substrate) and second surface (contact surface with sensor chip) of the magnetism collecting member, while leaving the third surface (side surface) unprocessed. This selective surface treatment ensures high flatness where gaps would form and affect detection sensitivity, while avoiding unnecessary machining costs on surfaces where flatness is not critical.
2Stability of the object's composition
If the magnetism collecting member is held at 90° with the substrate, then stability is improved, but gap control between surfaces becomes difficult
Solution Approach 1:
The patent performs preliminary grinding or polishing of the first and second surfaces of the magnetism collecting member before assembly. By pre-processing these surfaces to achieve high flatness, the patent ensures that when the magnetism collecting member is held at 90° with the substrate, the gap between the element formation surface and the magnetism collecting member is minimized, thereby maintaining both stability and precise gap control.
Data Source
AI summary
An object of the present invention is to provide a magnetic sensor capable of, while suppressing an increase in manufacturing cost, controlling the gap size so as to make the gap between the element formation surface of the sensor chip and the magnetism collecting member as small as possible and to make variations among products fall within a certain range and a manufacturing method for such a magnetic sensor. A magnetic sensor includes a sensor chip 20a mounted on a substrate 2 such that the element formation surface 20a is perpendicular to the substrate 2 and a magnetism collecting member 30 mounted on the substrate 2 such that the surface 31 faces the substrate 2 and the surface 32 faces the element formation surface 20a. The surfaces 31 and 32 of the magnetism collecting member 30 have flatness higher than that of the other surfaces thereof.