Process state detector, semiconductor sensor and display device for displaying a process state used therefor

• US 6,016,706 A
• Filed: 12/19/1996
• Issued: 01/25/2000
• Est. Priority Date: 04/23/1992
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Yoshimi, Tobita, Tomoyuki, Nagasu, Akira
• Primary Examiner(s): Oen, William L.
• Application Number:
  US08/769,385
• Time in Patent Office: 1,132 Days
• Field of Search: 73/708, 73/720, 73/721, 73/726, 73/727, 338/3, 338/4, 374/143
• US Class Current: 73/727
• CPC Class Codes: G01L 19/02 Arrangements for preventing, or for compensating for, effects of inclination or acceleration of the measuring device; Zero-setting means for aneroid barometers G01L7/14
• CPC Class Codes: G01L 19/146 using flexible element between the transducer and the support
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: G01L 9/065 with temperature compensating means non electric temperature compensating means G01L19/04

Abstract

In a multiple function type differential pressure sensor including a semiconductor chip having a differential pressure detector for detecting a differential pressure, temperature detector for detecting a temperature, and static pressure detector for detecting a static pressure provided on a semiconductor substrate of a single chip, two or more pairs of differential pressure detectors means are incorporated, and a difference between outputs of the two or more pairs of differential pressure detectors is fetched out.

Claims

1. A process state detector comprising:

a first differential sensor including a first set of resistors and sensitive to one physical state of a process whereby a resistance value of said first set of resistors is changed, and

a second differential sensor including a second set of resistors and sensitive to said one physical state of said process whereby a resistance value of said second set of resistors is changed;

a resistance value difference monitor receiving as inputs the resistance value of said first set of resistors and the resistance value of said second set of resistors, said monitor adapted to monitor long-term accuracy of the differential sensors by monitoring said resistances of said first set of resistors and said resistances of said second set of resistors respectively and comparing the resistances thereof; and

a static pressure sensor, an output of said static pressure sensor and said difference monitor being used to compensate a differential pressure.

2. A process state detector according to claim 1, further including a differential pressure sensitive diaphragm, wherein said first set of resistors and said second set of resistors are provided at a portion adjacent to said differential pressure sensitive diaphragm where distortion occurs, and said static pressure sensor is provided at a thick part of the detector apart from said differential pressure sensitive diaphragm where it is not affected by the distortion.

5. A process state detector according to claim 1, wherein a number of said first set of resistors is four and a number of said second set of resistors is four.

7. A process state detector according to claim 1, wherein said monitor is adapted to compare said resistances based on detected values over a period of time.

8. A process state detector according to claim 2, wherein said monitor includes a memory and is adapted to compare values of said resistances stored over a period of time.

9. A process state detector according to claim 1, wherein said monitor include a memory storing data from said first and second differential sensors, said monitor adapted to compare said stored data.

10. A process state detector according to claim 9, wherein said monitor compares data stored over a period of time.

11. A process state detector according to claim 9, wherein said memory stores a multi dimensional map interrelating at least three elements.

12. A process state detector according to claim 11, wherein said at least three elements include differential pressure, static pressure and temperature.

3. A process state detector comprising:

a first differential sensor including a first set of resistors and sensitive to one physical state of a process whereby a resistance value of said first set of resistors is changed, and

a second differential sensor including a second set of resistors and sensitive to said one physical state of said process whereby a resistance value of said second set of resistors is changed;

a resistance value difference monitor receiving as inputs the resistance value of said first set of resistors and the resistance value of said second set of resistors, said monitor adapted to monitor long-term accuracy of the differential sensors by monitoring said resistances of said first set of resistors and said resistances of said second set of resistors respectively and comparing the resistances thereof; and

a temperature sensor, an output of said temperature sensor and said difference monitor being used to compensate a differential pressure.

4. A process state detector according to claim 3, further including a differential pressure sensitive diaphragm, wherein said first set of resistors and said second set of resistors are provided at a portion adjacent to said differential pressure sensitive diaphragm where distortion occurs, and said temperature sensor is provided at a thick part of the detector apart from said differential pressure sensitive diaphragm where it is not affected by the distortion.

6. A process state detector according to claim 3, wherein a number of said first set of resistors is four and a number of said second set of resistors is four.

13. A process state detector comprising:

a first differential pressure sensor sensitive to one physical state of a process providing a first output;

a second differential sensor sensitive to said one physical state of said process providing a second output;

a difference monitor receiving as inputs said first and second outputs;

an auxiliary sensor having a third output, said third output and the output of said difference monitor being used to compensate a differential pressure; and

said difference monitor receiving said first and second outputs as inputs and adapted to store and compare values of said first and second outputs obtained at different times.

14. A process state detector according to claim 13 wherein each of said first and second differential sensors include respectively a first set of resistors and a second set of resistors and said monitor receives as inputs a first resistance value obtained from said first set of resistors and a second resistance value obtained from said second set of resistors, said monitor adapted to store and compare said first and second resistance values.

15. A process state detector according to claim 14 wherein said first and second resistance values comprise the resistance values of single corresponding resistors in said first and second sets.

16. A process state detector according to claim 14 wherein said first and second resistance values comprise the resistance values of combined resistors in said first and second sets.

17. A process state detector according to claim 13 wherein said monitor is adapted to correct a differential pressure value for changes occurring over time.

18. A process state detector according to claim 13 wherein said monitor includes a programmed processor and a memory.

19. A process state detector according to claim 13 wherein said auxiliary sensor is a static pressure sensor or a temperature sensor.

20. A process state detector according to claim 13 including both a static pressure sensor and a temperature sensor.

21. A process state detector according to claim 13, wherein said memory stores a multidimensional map interrelating at least three elements.

22. A process state detector according to claim 20, wherein said memory stores a multidimensional map interrelating at least differential pressure, static pressure and temperature.