摘要:
A thermal air flow sensor that produces less measurement error is provided. The thermal air flow sensor includes: a semiconductor substrate; a heating resistor, resistance temperature detectors, and an electrical insulator that includes a silicon oxide film, wherein the heating resistor, the resistance temperature detectors, and the electrical insulator are formed on the semiconductor substrate; and a diaphragm portion formed by removing a portion of the semiconductor substrate. The heating resistor and the resistance temperature detectors are formed on the diaphragm portion. The thermal air flow sensor further includes a silicon nitride film formed as the electrical insulator above the heating resistor and the resistance temperature detectors. The silicon nitride film has steps conforming to the patterns of the heating resistor and the resistance temperature detectors. The silicon nitride film has a multilayer structure.
摘要:
There is provided a fluid measurement device that is high in measurement precision. The fluid measurement device has a circuit unit into which a first signal S1 output from a first detection element and a second signal S2 output from a second detection element are to he input, wherein the circuit unit includes signal processing means that outputs a third signal S3 according to the first signal and the second signal, state deciding means that decides a state of the first signal, and control means that controls an amount of change that a change of the first signal imparts to the third signal in accordance with a result of decision by the state deciding means.
摘要:
An object of the present invention is to provide a thermal type flow rate sensor that offers high sensitivity and improved reliability. A sensor element according to the present invention includes a semiconductor substrate, a cavity portion formed on the semiconductor substrate, a heating resistor formed on the cavity portion via an electrically insulating film, a heating temperature sensor for detecting heating temperature of the heating resistor, and a driving circuit for controlling the heating temperature of the heating resistor using the temperature detected by the heating temperature sensor. The heating temperature sensor comprises temperature-sensitive resistors having resistance values varying according to temperature and disposed upstream and downstream of a direction of flow of a fluid to be measured relative to the heating resistor and on upper and lower sides in a direction perpendicular to the direction of flow of the fluid to be measured relative to the heating resistor.
摘要:
The invention provides a flow sensor structure for sealing the surface of an electric control circuit and a part of a semiconductor device via a manufacturing method capable of preventing occurrence of flash or chip crack when clamping the semiconductor device via a mold. The invention provides a flow sensor structure comprising a semiconductor device having an air flow sensing unit and a diaphragm formed thereto, and a board or a lead frame having an electric control circuit for controlling the semiconductor device disposed thereto, wherein a surface of the electric control circuit and a part of a surface of the semiconductor device is covered with resin while having the air flow sensing unit portion exposed. The invention further provides flow sensor structure in which surfaces of a resin mold, a board or a pre-mold component surrounding the semiconductor device are continuously not in contact with three walls of the semiconductor device orthogonal to a side on which the air flow sensing unit portion is disposed, or a manufacturing method for absorbing the dimensional variation of the semiconductor device by the deformation of springs or deformation of an elastic film in the thickness direction.
摘要:
An intake air temperature sensor capable of detecting an intake air temperature highly accurately and at high speed. The intake air temperature sensor of the present invention includes: a secondary passage 7 taking in an intake airflow; a flow rate detecting element 13 disposed in the secondary passage 7; an intake air temperature detecting element 4 provided outside the secondary passage; a temperature sensor 9 detecting a temperature of a fitting section of the intake air temperature detecting element 4; a circuit board 11 disposed in a casing; and an integrated circuit 10 applying a correction process to an output of the intake air temperature detecting element 4 on the basis of signals output from the temperature sensor 9 and a flow rate detecting element 13.
摘要:
In relation to a humidity sensor sensitive to water and contamination, a sensor implementation structure that achieves both protection performance against water and contaminants and measurement performance such as humidity responsiveness is provided. A sensor structure has a mass airflow measurement element that measures a mass airflow flowing in an intake pipe, a humidity sensing element that senses humidity of air flowing in the intake pipe, a housing structural component having a connector that carries out input/output to/from outside and a terminal component of the connector, and a bypass passage that is composed by using part of the housing structural component and takes in part of the air that flows in the intake pipe, the mass airflow measurement element being mounted in the bypass passage; wherein space is provided in the housing structural component in the vicinity of the bypass passage, the humidity sensing element is mounted in the space.
摘要:
A thermal flow sensor includes a heater temperature controller that realizes stable startup characteristics and prevents degradation of a sensor element and can also accommodate a smaller heater. The sensor also includes a semiconductor substrate; a cavity portion provided in the semiconductor substrate; a dielectric film provided on the semiconductor substrate; a thin layer area formed as a result of the dielectric film covering the cavity portion; a heating resistor provided in the thin layer area on the dielectric film; a first temperature-sensitive resistor provided in the thin layer area on the dielectric film; a heating controller; a second temperature-sensitive resistor provided near the heating resistor; and a flow rate detector that detects a flow rate of a fluid on the basis of temperature of the second temperature-sensitive resistor. The heating controller controls the temperature of the heating resistor on the basis of first and second reference temperatures.
摘要:
The present invention provides a highly-sensitive thermal-type flow-rate sensor with enhanced reliability. Provided is a thermal-type flow-rate sensor including: a passage into which a measurement-target fluid is introduced; and a sensor element which is provided in the passage and which measures the flow rate of the measurement-target fluid. The sensor element 1 includes: a semiconductor substrate; a hollow portion formed in the semiconductor substrate; and a heating resistor formed on an electric insulating film above the hollow portion. The sensor element measures the flow rate of the measurement-target fluid by radiating heat from the heating resistor to the measurement-target fluid. When Lh is the length of the heating resistor in a direction perpendicular to a flowing direction of the measurement-target fluid and Wd is the shortest distance to an upstream-side edge of the heating resistor from an edge of the hollow portion (an outer peripheral edge of a diaphragm) in the flowing direction of the measurement-target fluid, Wd≧0.4×Lh is satisfied in a relation between Lh and Wd.
摘要:
In a thermal air flow sensor according to the invention, a hollow formed in a detecting element is communicated with a circuit chamber, in which driving circuit parts of the detecting element are mounted, or an intake duct exterior. Thereby, pressure in the hollow balances with pressure on the outside. Also, since the circuit chamber is provided to be isolated from a detection chamber, in which a detecting part of the detecting element is arranged, that is, a passage chamber, through which air being a measuring object flows, air flowing in the passage chamber can be restrained from flowing into the hollow to have an influence on flow output characteristics.