WO1999036789A1 - Dispositif reagissant a l'acceleration - Google Patents

Dispositif reagissant a l'acceleration Download PDF

Info

Publication number
WO1999036789A1
WO1999036789A1 PCT/GB1999/000019 GB9900019W WO9936789A1 WO 1999036789 A1 WO1999036789 A1 WO 1999036789A1 GB 9900019 W GB9900019 W GB 9900019W WO 9936789 A1 WO9936789 A1 WO 9936789A1
Authority
WO
WIPO (PCT)
Prior art keywords
field effect
effect transistor
region
acceleration
conduction
Prior art date
Application number
PCT/GB1999/000019
Other languages
English (en)
Inventor
Brian Johnson
Original Assignee
First Inertia Switch Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by First Inertia Switch Limited filed Critical First Inertia Switch Limited
Priority to AU20639/99A priority Critical patent/AU2063999A/en
Publication of WO1999036789A1 publication Critical patent/WO1999036789A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/12—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by alteration of electrical resistance
    • G01P15/124—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by alteration of electrical resistance by semiconductor devices comprising at least one PN junction, e.g. transistors

Definitions

  • the conventional inertia switch comprises an inertia body whose position varies according to the acceleration experienced by the device. When the acceleration passes a given threshold, the inertia body moves to make or break the connection between electrical contacts of the switch.
  • Such a switch has a plurality of components which have to be assembled in the correct relative positions and their relative movement and electrical connections may become hindered by dirt and corrosion during the life of the switch.
  • the present invention aims to overcome such problems by providing an inertia body which is mounted on a base by a solid state member which has a relatively weak region, the member forming a field effect transistor (FET) .
  • FET field effect transistor
  • the member bends about the relatively weak region and changes the conduction of the field effect transistor. This change of conduction can be sensed by an electrical circuit; the field effect transistor may in effect form an electrical switch which can be used in the same way as a conventional inertia switch.
  • Biasing means may be provided for the field effect transistor in order to vary the relationship of the output signal to the experienced acceleration.
  • the member preferably comprises a main body portion of one conductivity type, the region of weakness comprising the opposite conductivity type.
  • the region of weakness may comprise a groove formed in the wall of the member.
  • the member may be cylindrical, in which case the groove may be an annular groove.
  • the base can be fixed on a printed circuit board whose circuit senses the conduction change of the FET.
  • a field effect transistor is much superior to a piezo-electric device since the latter does not have a d.c. response.
  • the piezo-electric device generates a charge in response to an applied force and the charge is dissipated by measurement.
  • the transistor is a switch whose conductivity state can be continuously monitored.
  • Figure 2 is an equivalent electrical circuit of the device of Figure 1 and Figure 3 shows a possible mounting arrangement.
  • a cylindrical semiconductor member 11 extends between a reference base 12 and an inertia body 13. At an intermediate region in the member an annular groove 14 is formed. In the region 15 adjacent the annular groove, the semiconductor member is P-type, the remainder 16 of the semiconductor member being N-type. Electrical connections (not shown in Figure 1) are made to the semiconductor member to suitable biasing voltages and an output terminal .
  • the semiconductor member forms a field effect transistor 21 as shown in Figure 2, provided with biasing voltage V, the gate terminal 22 of the field effect transistor being connected to a potentiometer 23 connected across the main biasing voltage 24 in order to adjust the sensitivity of the field effect transistor.
  • the semiconductor switch According to the bending of the member 11 due to the acceleration forces on the inertia body, the semiconductor switch will change its conductivity state at an acceleration depending on the setting of the potentiometer 23.
  • the conductivity of the transistor is sensed at terminal TO and can be processed in a conventional manner to form a circuit which responds to the acceleration experienced by the inertia body.
  • Figure 3 shows a micromachined silicon chip 31 as a detail which can then be mounted in a transistor-type case 33 on a printed circuit board 34 acting as an active beam itself mounted in cantilever fashion on a body being accelerated.
  • the body 36 has a shoulder 35 over which one edge of the printed circuit board is bolted.
  • the silicon chip has three terminals 37 which are connected to appropriate points 38 on the printed circuit board in conventional manner.
  • the proof mass or inertia body on its semiconductor supporting arm which is formed with the annular groove as described with reference to Figure 1.
  • the device is most sensitive to acceleration in the vertical direction as seen in Figure 3, indicated by the arrow 39 pointing upwards towards the printed circuit board.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Pressure Sensors (AREA)

Abstract

L'invention concerne un dispositif réagissant à l'accélération, lequel comprend un corps à inertie (13) monté sur une base (12) via un élément transistorisé (11) qui comporte une zone relativement faible (14), cet élément (11) formant un transistor à effet de champ.
PCT/GB1999/000019 1998-01-13 1999-01-05 Dispositif reagissant a l'acceleration WO1999036789A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU20639/99A AU2063999A (en) 1998-01-13 1999-01-05 Acceleration responsive device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9800676.0 1998-01-13
GBGB9800676.0A GB9800676D0 (en) 1998-01-13 1998-01-13 Acceleration responsive device

Publications (1)

Publication Number Publication Date
WO1999036789A1 true WO1999036789A1 (fr) 1999-07-22

Family

ID=10825223

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/000019 WO1999036789A1 (fr) 1998-01-13 1999-01-05 Dispositif reagissant a l'acceleration

Country Status (3)

Country Link
AU (1) AU2063999A (fr)
GB (1) GB9800676D0 (fr)
WO (1) WO1999036789A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0194953A1 (fr) * 1985-03-01 1986-09-17 Metravib S.A. Capteur intégré de grandeurs mécaniques à effet capacitif et procédé de fabrication
US4772928A (en) * 1985-04-27 1988-09-20 Messerschmitt-Bolkow-Blohm Gmbh Electric transducer for measuring mechanical quantities
US5103279A (en) * 1990-10-18 1992-04-07 Motorola, Inc. Field effect transistor with acceleration dependent gain

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0194953A1 (fr) * 1985-03-01 1986-09-17 Metravib S.A. Capteur intégré de grandeurs mécaniques à effet capacitif et procédé de fabrication
US4772928A (en) * 1985-04-27 1988-09-20 Messerschmitt-Bolkow-Blohm Gmbh Electric transducer for measuring mechanical quantities
US5103279A (en) * 1990-10-18 1992-04-07 Motorola, Inc. Field effect transistor with acceleration dependent gain

Also Published As

Publication number Publication date
GB9800676D0 (en) 1998-03-11
AU2063999A (en) 1999-08-02

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