Denso Corporation

Nippondenso Co., Ltd.

Seiichirou Otake

Hiroaki Tanaka

Inao Toyoda

Yukihiro Kato

Kazuyoshi Nagase

Teruo Oda

Yoshifumi Watanabe

Toshio Ikuta

Shinji Ozaki

A pressure detecting device includes a semiconductor substrate () for outputting an electrical signal corresponding to an applied pressure received from a pressure transmitting member () having electrically conductive properties disposed on the front surface of the semiconductor substrate (). The substrate () and the pressure transmitting member () are accommodated in a housing (). A lead member () electrically independent of the housing () is accommodated in the housing () at the back surface side of the semiconductor substrate (), and the lead member () and an electrode () of the substrate () are electrically connected to each other through conductive adhesive material (). The housing () preferably includes a first portion (), a second portion () having smaller thermal conductivity than the first portion, and an electrically conductive partition portion ().

Pressure detecting device

A digital-to-analog converter includes an R-2R resistive ladder network having resistors connected in a ladder form in correspondence with a number of bits of a digital input signal. The R-2R resistive ladder network has an output terminal. A pair of positive and negative dc-power-supply terminals are connected to the R-2R resistive ladder network. Currents flowing between the R-2R resistive ladder network and one of the positive and negative dc-power-supply terminals are controlled in response to the bits of the digital input signal to generate an analog voltage signal at the output terminal of the R-2R resistive ladder network. The analog voltage signal depends on the digital input signal. A first resistor and a second resistor located outside the R-2R resistive ladder network are connected in series between the positive and negative dc-power-supply terminals. A third resistor located outside the R-2R resistive ladder network is connected between the output terminal of the R-2R resistive ladder network and the second resistor located outside the R-2R resistive ladder network. A conversion output terminal is connected to a junction between the second and third resistors located outside the R-2R resistive ladder network.

Digital-to-analog converter and sensor-characteristic adjustment circuit

A liquid-sealed type semiconductor pressure sensor with no filling orifice includes a connector housing which is made of high polymer compound material of high air permeability and which has a recess and connector pins, where a main housing which has a sealing diaphragm is secured to the connector housing airtightly and a pressure sensitive element is disposed in the recess and is electrically connected to external circuitry by connector pins. A pressure detecting chamber formed between the recess and the sealing diaphragm is filled with pressure transmitting medium, such as silicone oil, having high air solubility. To manufacture the sensor, the recess is filled with a fixed volume of the pressure transmitting medium, the main housing is placed on the connector housing, and a prescribed pressure is applied to the sensor to dissolve air trapped in the pressure detecting chamber during the previous step into the transmitting medium and to purge the rest through the high polymer compound materials used in the connector housing. As a result, a non-linear pressure rise in the pressure detecting chamber can be prevented.

Liquid-sealed semiconductor pressure sensor and manufacturing method

A pressure detector comprises a pressure sensitive element composed of a semiconductor substrate having at least four gauge resistances and outputting signal in response to a pressure. A pressure transmission member is provided on the surface having the gauge resistors of the pressure sensitive element, for transmitting the pressure to the pressure sensitive element. Taking a crystal face of (110) as the face orientation of the pressure sensitive element, a bridge circuit is constructed by disposing a pair of gauge resistors in the direction of &lt;110&gt; of the crystal axis, disposing another pair of gauge resistors in the direction of &lt;100&gt; of the crystal axis and by connecting them each other. The bridge circuit is located within a pressurized surface which the pressure transmission member presses. Further, temperature compensating resistors are disposed in the direction of &lt;100&gt; of the crystal axis so as to be located also within the area of the pressurized surface.

Growing community of inventors

Hazu-gun, Japan

Seiichirou Otake