The present disclosure is directed to a gas sensor device that includes a plurality of gas sensors. Each of the gas sensors includes a semiconductor metal oxide (SMO) film, a heater, and a temperature sensor. Each of the SMO films is designed to be sensitive to a different gas concentration range. As a result, the gas sensor device is able to obtain accurate readings for a wide range of gas concentration levels. In addition, the gas sensors are selectively activated and deactivated based on a current gas concentration detected by the gas sensor device. Thus, the gas sensor device is able to conserve power as gas sensors are on when appropriate instead of being continuously on.

A gas sensor package includes a package substrate having a hole, the hole having an end that is opened at a first surface of the package substrate; a gas sensor disposed in the hole of the package substrate; a fixing plate disposed on the first surface of the package substrate, the fixing plate having a vent hole extending between a top surface and a bottom surface of the fixing plate, the bottom surface of the fixing plate facing toward the package substrate and the top surface of the fixing plate facing away from the package substrate, and the fixing plate overlapping the hole of the package substrate when viewed in a plan view; and a protective film attached to the fixing plate. The protective film overlaps the vent hole when viewed in a plan view.

A microhotplate comprising a membrane suspended over a substrate by a plurality of tethers connected between the substrate and the membrane. The membrane comprises a resistive heater comprising an electrically conductive material having a varying width from a peripheral portion of the membrane to a center of the membrane. The electrically conductive material comprises a first portion spiraling in a first direction and a second portion spiraling in a second direction and in electrical communication with the first portion at the center of the membrane. The microhotplate further comprises a first electrically conductive trace extending over a first tether and in electrical contact with a bond pad on the substrate and the first portion and a second electrically conductive trace extending over another tether and in electrical contact with another bond pad on the substrate and the second portion. Related chemical sensors and related methods of detecting at least one analyte are also disclosed.

The present disclosure is directed to a gas sensor device that includes a plurality of gas sensors. Each of the gas sensors includes a semiconductor metal oxide (SMO) film, a heater, and a temperature sensor. Each of the SMO films is designed to be sensitive to a different gas concentration range. As a result, the gas sensor device is able to obtain accurate readings for a wide range of gas concentration levels. In addition, the gas sensors are selectively activated and deactivated based on a current gas concentration detected by the gas sensor device. Thus, the gas sensor device is able to conserve power as gas sensors are on when appropriate instead of being continuously on.

A gas sensor with improved sensitivity. The gas sensor comprises an active sensor unit, a reference sensor unit and a temperature control circuit. The active sensor unit has an active detector. The reference sensor unit has a reference detector. The temperature control circuit is provided and configured to keep a detector at a predetermined temperature.

The invention is notably directed to a gas sensor. The gas sensor basically comprises a hotplate, a support structure, a gas selective filter, and a circuitry. The support structure is configured so as define (or contribute to define) a cavity. It further supports the hotplate. The gas selective filter is held by the support structure. This filter spans the cavity. The filter may notably be designed to filter gas molecules according to their sizes. The circuitry includes one or more integrated circuits. Beside the integrated circuits, various components are connected to the circuitry. Such components include a temperature sensor element, a gas sensing element, and a heater. The temperature sensor element is arranged on or in a part of the support structure. The temperature sensor element is configured to sense a temperature T.sub.f of the filter. The gas sensing element is arranged on or in the hotplate, so as to be sensitive to a target gas in the cavity. The heater is arranged on or in the hotplate, so as to be in thermal communication with the gas sensing element. The circuitry, as a whole, is configured to operate the sensing element, estimate a temperature T.sub.f of the filter, and regulate the heater. The circuitry operates the gas sensing element by supplying power to the heater for the latter to heat the gas sensing element and by processing signals received from the gas sensing element. The circuitry estimates the temperature T.sub.f of the filter based on signals received from the temperature sensor element. Thus, the circuitry can regulate an extent to which power is supplied to the heater based on the estimated temperature T.sub.f of the filter.

The present invention relates to methods for detecting gases in an environment using chemical and thermal sensing. In one embodiment, a method includes exposing a chemiresistor embedded within a sensor pixel to a gas in an environment; setting a heater embedded within the sensor pixel to a sensing temperature, the sensing temperature being greater than room temperature; measuring an electrical resistance of the chemiresistor in response to setting the heater to the sensing temperature; and in response to a difference between the electrical resistance of the chemiresistor and a reference electrical resistance being less than a threshold, supplying a fixed power input to the heater embedded within the sensor pixel and measuring a temperature of the sensor pixel relative to a reference temperature.

A portable communication device may include a gas sensor enclosed in an enclosure, a port to allow flow of air into and out of the enclosure, and a light source disposed on an internal surface of the enclosure. The light source is operable to facilitate generation of ozone gas within the enclosure. The enclosure may contain a heating element that allows baseline calibration of the gas sensor by thermally decomposing ozone gas molecules. The gas sensor includes a miniature gas sensor such as a metal-oxide (MOX) gas sensor.

A gas detector comprises: plural gas sensors provided with a metal-oxide semiconductor whose resistance changes based upon contact with a gas; and a driving circuit for operating the gas sensors. The gas detector stores the ratio between initial resistance in air of the metal-oxide semiconductor and initial resistance of the metal-oxide semiconductor in an atmosphere including a predetermined concentration of fron gas, for the plural gas sensors. The gas detector learns resistance in air of the metal-oxide semiconductor in a gas sensor in use, and detects occurrence of fron gas when resistance of the metal-oxide semiconductor of the gas sensor in use becomes lower than a value corresponding to the learned resistance in air divided by the ratio. The gas detector counts the period that a first gas sensor is used. When the first gas sensor has been used for a predetermined period, both the first gas sensor and a second gas sensor are used for a learning period to continue detection of fron by the first gas sensor and to learn the resistance in air of the metal-oxide semiconductor of the second gas sensor. After completion of the learning period, fron leakage is detected by the second gas sensor.

A monolithic gas-sensing chip assembly for sensing a gas analyte includes a sensing material to detect the gas analyte, a sensing system including a resistor-capacitor electrical circuit, and a heating element. A sensing circuit measures an electrical response of the sensing system to an alternating electrical current applied to the sensing system at (a) one or more different frequencies, or (b) one or more different resistor-capacitor configurations of the system. One or more processors control a low detection range of the system to the gas, a high detection range of the system to the gas, a linearity of a response of the system to the gas, a dynamic range of measurements of the gas by the system, a rejection of interfering gas analytes by the system, a correction for aging or poisoning of the system, or a rejection of ambient interferences that may affect the electrical response of the system.