US4543457A — Microminiature force-sensitive switch

Claim 1

Independent Claim 108 words

A microminiature, force-sensitive, multi-state switch comprising a silicon wafer having a reduced-thickness, deflectable membrane adapted to move from a relaxed condition toward increasingly strained conditions upon the application of an increasingly greater force to the membrane, a stationary contact member disposed adjacent and spaced from the membrane, with the latter in its relaxed condition, said membrane and contact member forming a pair of confronting surfaces, a common terminal, a plurality of switch-state terminals, and electrical contact means associated with said confronting surfaces for connecting the common terminal first to one and then progressively to more of the switch-state terminals upon movement of the membrane toward increasingly strained conditions.

Claim 2

Dependent Claim 108 words

A microminiature, force-sensitive, multi-state switch comprising a silicon wafer having a reduced-thickness, deflectable membrane adapted to move from a relaxed condition toward increasingly strained conditions upon the application of an increasingly greater force to the membrane, a stationary contact member disposed adjacent and spaced from the membrane, with the latter in its relaxed condition, said membrane and contact member forming a pair of confronting surfaces, a common terminal, a plurality of switch-state terminals, and electrical contact means associated with said confronting surfaces for connecting the common terminal first to one and then progressively to more of the switch-state terminals upon movement of the membrane toward increasingly strained conditions.

Claim 3

Dependent Claim 59 words

The switch of claim 1, wherein said electrical contact means includes a plurality of spaced electrical contacts carried on one of the confronting surfaces, means connecting each contact conductively to a corresponding switch-state terminal, and conductor means carried on the other of said confronting surfaces, adapted to connect said common terminal to said contacts progressively upon such membrane movement.

Claim 4

Dependent Claim 31 words

The switch of claim 2, wherein said conductor means includes a conductive expanse carried on the surface of said other confronting surface, and means connecting said expanse to said common terminal.

Claim 5

Dependent Claim 29 words

The switch of claim 3, wherein said contacts are carried on the surface of the membrane, and said expanse is carried on the surface of said stationary contact member.

Claim 6

Dependent Claim 30 words

The switch of claim 1, wherein said membrane includes a diaphragm adapted to move to increasingly bulged positions upon the application of a force to one side of the diaphragm.

Claim 7

Dependent Claim 30 words

The switch of claim 5, for use in sensing the pressure of an external fluid, which further includes means forming a fluid-tight chamber covering the other side of said diaphragm.

Claim 8

Dependent Claim 30 words

The switch of claim 6, wherein said stationary contact member includes a plate which is sealed to side regions of said wafer which surround the diaphragm, to form said chamber.

Claim 9

Dependent Claim 49 words

The switch of claim 1, wherein said membrane extends between, and is formed integrally with, opposite side regions of said wafer, and the application of force to said membrane is adapted to produce membrane bulging which spreads outwardly from the membrane's central region as the membrane becomes more strained.

Claim 10

Dependent Claim 65 words

The switch of claim 8, wherein said electrical contact means includes a plurality of groups of electrical contacts, where each group including a pair of contacts carried on the surface of the membrane, substantially symmetrically with respect to the central region thereof, and the groups are arranged in progressively more outwardly disposed pairs, and means connecting each group of contacts to a corresponding switch-state terminal.

Claim 11

Dependent Claim 60 words

The switch of claim 9, wherein the membrane includes a diaphragm adapted, upon the application of force thereto, to form a central bulge which spreads increasingly outwardly, substantially symmetrically in all directions, upon application of an increased force to the diaphragm, and each group of electrical contacts includes a multiplicity of contacts arrayed symmetrically with respect to such force-produced bulging.

Claim 12

Dependent Claim 42 words

The switch of claim 1, wherein said silicon wafer includes a boron-doped silicon layer sandwiched between a silicon layer and a silicon epitaxial layer, and said membrane is composed of the boron-doped silicon layer and a reduced-thickness portion of the epitaxial layer.

Claim 13

Dependent Claim 32 words

The switch of claim 11, wherein said membrane includes a diaphragm having a thickness of between about 10 and 50 microns, and a side-to-side dimension of between about 0.5 to 2 millimeters.

Claim 14

Dependent Claim 153 words

A microminiature switch for digitizing or monitoring changes in an external condition, such as pressure, temperature or acceleration, said switch comprising a silicon wafer having a reduced-thickness deflectable membrane adapted to move between a relaxed condition and a continuum of increasingly strained conditions in response to greater-value changes in such external condition, a stationary contact member disposed adjacent and spaced from the deflectable membrane, with the latter in its relaxed condition, said membrane and said contacting member defining a pair of confronting surfaces, a common terminal, a plurality of switch-state terminals, a plurality of spaced electrical contacts carried on one of said surfaces, means connecting each contact conductively to a corresponding switch-state terminal, and conductor means carried on the other of said surfaces, adapted to connect said common terminal first to one, then progressively to more of said switch-state contacts upon movement of the membrane from its relaxed condition toward increasingly strained conditions.

Claim 15

Dependent Claim 153 words

A microminiature switch for digitizing or monitoring changes in an external condition, such as pressure, temperature or acceleration, said switch comprising a silicon wafer having a reduced-thickness deflectable membrane adapted to move between a relaxed condition and a continuum of increasingly strained conditions in response to greater-value changes in such external condition, a stationary contact member disposed adjacent and spaced from the deflectable membrane, with the latter in its relaxed condition, said membrane and said contacting member defining a pair of confronting surfaces, a common terminal, a plurality of switch-state terminals, a plurality of spaced electrical contacts carried on one of said surfaces, means connecting each contact conductively to a corresponding switch-state terminal, and conductor means carried on the other of said surfaces, adapted to connect said common terminal first to one, then progressively to more of said switch-state contacts upon movement of the membrane from its relaxed condition toward increasingly strained conditions.

Claim 16

Dependent Claim 30 words

The switch of claim 13, wherein said membrane includes a diaphragm whose increasingly strained conditions take the form of increased bulging in the diaphragm outwardly from a central region thereof.

Claim 17

Dependent Claim 42 words

The switch of claim 14, for use in digitizing or monitoring changes in the pressure of an external fluid in contact with one side of the diaphragm, which further includes means forming a fluid-tight chamber covering the other side of the diaphragm.

Claim 18

Dependent Claim 41 words

The switch of claim 14, for use in digitizing or monitoring changes in acceleration force, which further includes a mass attached to the diaphragm to effect such bulging in response to changes in an acceleration force in the direction of bulging.

Claim 19

Dependent Claim 27 words

The switch of claim 14, for use in digitizing or monitoring changes in temperature, wherein said membrane includes a metal layer formed on a reduced-thickness silicon layer.

Claim 20

Dependent Claim 49 words

The switch of claim 13, wherein said membrane includes an elongate beam having opposed fixed and free end regions, and which is adapted to contact the stationary contact member at its free end region initially and progressively more toward its fixed end region upon movement toward increasingly strained conditions.

Claim 21

Dependent Claim 31 words

The switch of claim 18, for use in digitizing or monitoring changes in switch acceleration forces, which further includes a series of mass elements carried on the beam's free end region.

Claim 22

Dependent Claim 29 words

The switch of claim 18, for use in digitizing or monitoring changes in temperature, wherein the beam is composed of a metal layer formed on a reduced-thickness silicon layer.

Claim 23

Dependent Claim 164 words

A microminiature switch for digitizing or monitoring changes in an external pressure, comprising a silicon wafer having a flexible, reduced-thickness diaphragm adapted to move from a relaxed condition toward increasingly bulged conditions upon the application of a pressure-related force to one side of the said diaghram, a contact plate disposed adjacent and spaced from the other side of the diaphragm, and sealed to side regions of the wafer bordering the diaphragm, to form a fluid-tight chamber covering said other side of the diaphragm, the diaphragm and the plate defining a pair of confronting surfaces within said chamber, a common terminal, a plurality of switch-state terminals, a plurality of spaced electrical contacts carried on one of said confronting surfaces, means connecting each contact conductively to a corresponding switch-state terminal, and conductor means carried on the other confronting surfaces, adapted to connect said common terminal first to one and then progressively to more of the switch-state terminals upon movement of the diaphragm toward increasingly strained conditions.

Claim 24

Dependent Claim 164 words

A microminiature switch for digitizing or monitoring changes in an external pressure, comprising a silicon wafer having a flexible, reduced-thickness diaphragm adapted to move from a relaxed condition toward increasingly bulged conditions upon the application of a pressure-related force to one side of the said diaghram, a contact plate disposed adjacent and spaced from the other side of the diaphragm, and sealed to side regions of the wafer bordering the diaphragm, to form a fluid-tight chamber covering said other side of the diaphragm, the diaphragm and the plate defining a pair of confronting surfaces within said chamber, a common terminal, a plurality of switch-state terminals, a plurality of spaced electrical contacts carried on one of said confronting surfaces, means connecting each contact conductively to a corresponding switch-state terminal, and conductor means carried on the other confronting surfaces, adapted to connect said common terminal first to one and then progressively to more of the switch-state terminals upon movement of the diaphragm toward increasingly strained conditions.

Claim 25

Dependent Claim 28 words

The switch of claim 21, wherein the conductor means includes a conductive expanse carried on said other confronting surface, and means connecting said expanse to the common terminal.

Claim 26

Dependent Claim 31 words

The switch of claim 22, wherein the contacts are carried on the confronting surface of the diaphragm, and the conducting expanse is carried on the confronting surface of said contact plate.

Claim 27

Dependent Claim 70 words

The switch of claim 21, wherein the diaphragm is adpated to bulge symmetrically from a central bulge region outwardly upon the application of a greater pressure-related force, said contacts include a plurality of groups of contacts, the contacts in each group are arranged substantially symmetrically with respect to the center of the diaphragm, and said connecting means includes means connecting the contacts in each group to the corresponding switch-state terminal.

Claim 28

Dependent Claim 23 words

The switch of claim 23, wherein each group of contacts includes a multiplicity of contacts arrayed symmetrically about the center of the diaphragm.

Claim 29

Dependent Claim 101 words

A passive, microminiature diaphragm switch comprising a silicon wafer having a reduced-thickness, deflectable diaphragm adapted to move from a relaxed condition toward increasing bulged conditions upon the application of an increasingly greater force to the diaphragm, a stationary contact member disposed adjacent and spaced from the diaphragm, with the latter in its relaxed condition, the diaphragm and contact member defining a pair of confronting surfaces, a pair of switch terminals, and electrical contact means associated with said confronting surfaces for connecting said pair of switch terminals conductively when the diaphragm is moved from its relaxed condition to a preselected bulged condition.

Claim 30

Dependent Claim 101 words

A passive, microminiature diaphragm switch comprising a silicon wafer having a reduced-thickness, deflectable diaphragm adapted to move from a relaxed condition toward increasing bulged conditions upon the application of an increasingly greater force to the diaphragm, a stationary contact member disposed adjacent and spaced from the diaphragm, with the latter in its relaxed condition, the diaphragm and contact member defining a pair of confronting surfaces, a pair of switch terminals, and electrical contact means associated with said confronting surfaces for connecting said pair of switch terminals conductively when the diaphragm is moved from its relaxed condition to a preselected bulged condition.

Claim 31

Dependent Claim 50 words

The switch of claim 26, which is responsive to a selected change in fluid pressure applied to one side of the diaphragm, wherein the stationary contact member is sealed to edge regions of the wafer bordering the diaphragm to form a fluid-tight chamber covering the other side of the diaphragm.

Claim 32

Dependent Claim 40 words

The switch of claim 26, wherein the silicon wafer includes a boron-doped silicon layer sandwiched between a silicon layer and a silicon epitaxial layer, and the diaphragm includes the boron-doped silicon layer and a reduced-thickness portion of the epitaxial layer.

Claim 33

Dependent Claim 29 words

The switch of claim 28, wherein the diaphragm has a thickness of between about 10 and 50 microns and a side-to-side dimension of between about 0.5 and 2 millimeters.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-09-23	1989-03-25	1989-09-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-09-23	1993-03-25	1993-09-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-09-23	1997-03-25	1997-09-24	$7700.00	Window Closed / Lapsed

Microminiature force-sensitive switch

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