Magnetic sensor with encapsulated magnetically sensitive component and magnet

• US 5,631,557 A
• Filed: 02/16/1996
• Issued: 05/20/1997
• Est. Priority Date: 02/16/1996
• Status: Expired due to Fees

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Davidson, Robert M.
• Primary Examiner(s): O'Shea, Sandra L.
• Assistant Examiner(s): PHILLIPS, ROGER
• Application Number:
  US08/602,187
• Time in Patent Office: 459 Days
• Field of Search: 324/207.2-207.26, 324/174, 324/251, 324/252, 204/32.1, 338/32 R, 338/32 H
• US Class Current: 324/174
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01P 1/026 for speed measuring devices, e.g. pulse generator
• CPC Class Codes: G01P 3/488 delivered by variable reluctance detectors

Abstract

A magnetic sensor is provided in which a flexible substrate is used to support a magnetically sensitive component and other electronic components relative to the position of a permanent magnet. A thermoset material is used as an encapsulant to form a solid magnetic sensor in which the magnetically sensitive component, the permanent magnet and a portion of the flexible substrate are encapsulated within the thermoset material after it solidifies. A portion of the flexible substrate extends from an end of the solidified encapsulant to permit electrical connection to other components and devices.

Claims

1. A magnetic sensor, comprising:

a flexible substrate having a plurality of electrically conductive runs attached thereto;

a magnetically sensitive component attached to said flexible substrate, said magnetically sensitive component being connected in electrical communication with at least one of said plurality of electrically conductive runs;

a permanent magnet attached in a fixed position relative to said magnetically sensitive component, said magnetically sensitive component being disposed within the magnetic field of said permanent magnet proximate a magnetic pole of said permanent magnet, said flexible substrate being rigidly attached to said permanent magnet independently of the encapsulation provided by said quantity of solidified thermoset material and at a location, relative to said permanent magnet, determined by an active calibration procedure by which said flexible substrate is moved relative to said permanent magnet until said magnetically sensitive component provides a predetermined output signal, said permanent magnet being plated with a material to facilitate said flexible substrate being rigidly attached to said permanent magnet by solder;

a quantity of solidified thermoset material disposed around said permanent magnet, said magnetically sensitive component and a first portion of said plurality of electrically conductive runs, a second portion of said plurality of electrically conductive runs extending from said quantity of solidified thermoset material, said permanent magnet and said magnetically sensitive component being encapsulated within said quantity of solidified thermoset material; and

a hole through said flexible substrate, said solder extending through said hole to a surface of said permanent magnet from a surface of said flexible substrate which is facing away from said permanent magnet.

2. The sensor of claim 1, wherein:

said magnetically sensitive component comprises at least one magnetoresistive element.

3. The sensor of claim 1, wherein:

said magnetically sensitive component comprises a Hall effect element.

4. The sensor of claim 1, wherein:

said permanent magnet comprises neodymium, boron and iron.

5. The sensor of claim 1, wherein:

a plurality of electronic components is connected in electrical communication with preselected ones of said plurality of electrically conductive runs.