초록 ▼

A pressure sensor of the type having a semiconductor diaphragm such as a silicon diaphragm which is formed with at least one diffused resistor in a surface region on one side thereof. A silicon block having the diaphragm is bonded to the inside of a box-like package such that the diffused resistor i

A pressure sensor of the type having a semiconductor diaphragm such as a silicon diaphragm which is formed with at least one diffused resistor in a surface region on one side thereof. A silicon block having the diaphragm is bonded to the inside of a box-like package such that the diffused resistor is exposed in a vacuum chamber defined in the package and that a fluid pressure can arrive at the back side of the diaphragm through a hole of the package. To minimize unwanted straining of the silicon diaphragm by thermal influences, the package is made of a material such as mullite whose linear expansion coefficient is close to that of silicon. To prevent an accidental change in the output characteristic of the sensor by the influence of an unintended external force, the package is supported above a base plate by pillar-like lead frames and confined in a space provided by fixing a cap to the base plate. A pressure introduction pipe is attached to either the base plate or the cap.

대표청구항 ▼

A pressure sensor comprising: (a) a probe assembly comprising (i) a pressure-sensitive element comprising a block of a crystalline semiconductor a portion of which takes the form of a diaphragm having front and back sides and at least one diffused resistor formed in a surface region on said front si

A pressure sensor comprising: (a) a probe assembly comprising (i) a pressure-sensitive element comprising a block of a crystalline semiconductor a portion of which takes the form of a diaphragm having front and back sides and at least one diffused resistor formed in a surface region on said front side of said diaphragm; (ii) a package made up of at least two structural members integrated into a lidded box-like structure, said structural members being each made of an electrically nonconductive material whose coefficient of linear expansion is nearly equal to the coefficient of linear expansion of said crystalline semiconductor, said block of said pressure-sensitive element being confined in the interior of said package and bonded to one of said at least two structural members such that said diaphragm is entirely spaced apart from the inside of said package and that a hermetically closed first space is defined between the inside of said package and said front side of said diaphragm, said space being kept at a predetermined pressure so as to serve as a reference pressure chamber, said one of said at least two structural members further including a first hole bored therethrough in such a position that a fluid pressure subject to measurement can be admitted into the interior of said package through said hole so as to arrive at said back side of said diaphragm; and (iii) a plurality of lead frames which are elongate metal members fixed to said package so as to each protrude from the outside of said package and electrically connected to said at least one diffused resistor said lead frames comprising means for supporting the weight of said package; (b) a base plate having a plurality of electrical terminals, said lead frames being respectively fixed to said base plate at said electrical terminals such that said package is supported by said lead frames in a state entirely spaced from said base plate; (c) a cap fixed to said base plate such that a second space is defined between said cap and said base plate and that said probe assembly is entirely confined in said second space and spaced from the inside of said cap, one of said cap and said base plate having a second hole bored therethrough so as to open into said second space; and (d) a pipe fixed to said one of said cap and said base plate such that the interior of said pipe communicates with said second space only through said second hole to introduce said fluid pressure into said second space.