Geomagnetic sensor and geomagnetic sensor correction method, temperature sensor and temperature sensor correction method, geomagnetism detection device

• US 20060168832A1
• Filed: 02/02/2006
• Published: 08/03/2006
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Sato, Hideki, Omura, Masayoshi, Kaneko, Makoto, Yasui, Shoji
• Granted Patent: US 7,676,340 B2
• Time in Patent Office: Days
• US Class Current: 33/356
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses
• CPC Class Codes: G01K 7/01 using semiconducting elements having PN junctions G01K7/02, G01K7/16, G01K7/30 take precedence

Abstract

With regard to the geomagnetic sensor 1, the control logic circuit 11 conducts control of the geomagnetic sensor 1. When the geomagnetic sensor 1 is installed in a cell phone device, the control logic circuit 11 reads the measurement values pertaining to the ambient magnetic field from the geomagnetic sensor circuit 12, obtains the offset value from the pertinent measurement values, and stores it in the fuse memory 13. At times of measurement by the geomagnetic sensor 1, the control logic circuit 11 reads the offset value from the fuse memory 13, and corrects the measurement values of the geomagnetic sensor 12 using the pertinent value.

With regard to the temperature sensor 201, the control logic circuit 211 conducts control of the temperature sensor 201. During preparation of the temperature sensor 201, the control logic circuit 211 reads the result of measurement of the property pertaining to the ambient temperature from the temperature sensor circuit 212, obtains the initial value and correction value from the result, and stores the pertinent values in the fuse memory 213. At times of operation of the temperature sensor 201, the control logic circuit 211 reads the initial value and correction value from the fuse memory 213, and corrects the measurement values of the temperature sensor circuit 212 using the pertinent values.

The correction coefficients a11-a22 of the magnetic sensors are measured during LSI shipment inspection. The correction data D1-D4 obtained from these correction coefficients a11-a22 are written into the fuse memory 315. The control circuit 308 inputs the detection outputs Sx and Sy of the magnetic sensors 310 and 311 to the internal register during geomagnetism detection. The correction data D1-D4 is read from the fuse memory 315. Detection outputs Sx and Sy are corrected using formulas (309) to (312).

Claims

1. A geomagnetic sensor comprising:

a geomagnetism detection unit for detecting geomagnetism;

a fuse memory possessing a plurality of memory units, which enables a selective electrical cut-off or connection of each of said memory units, for storing prescribed data according to a state of the electrical cut-off or connection;

a correction data writing unit for inputting measurement values of said geomagnetism detection unit at a time of manufacture, for obtaining correction values that correct a temperature property of the measurement values of the geomagnetism detection unit based on said measurement values, and for writing said correction values into said fuse memory by conducting selective electrical cut-off or connection of each memory unit contained in said fuse memory according to said correction values;

a correction data reading unit for reading said correction values from said fuse memory at times of actual use after manufacture; and

a correction unit for inputting the measurement values of said geomagnetism detection unit at times of actual use, and for correcting the measurement values of said geomagnetism detection unit based on the correction values read by said correction data reading unit.

2. A geomagnetic sensor correction method for correcting the measurement values of a geomagnetic sensor according to claim 1 that is further provided with a temperature measurement unit for a detection of temperature by said geomagnetic sensor, the geomagnetic sensor correction method comprising:

a step in which a sensitivity property of said temperature measurement unit is obtained in advance, and stored in said fuse memory at a time of manufacture of said geomagnetic sensor;

a step in which the sensitivity property of said temperature measurement unit is corrected according to the sensitivity property data stored in said fuse memory; and

a step in which an offset of magnetic sensitivity is corrected according to the temperature of said geomagnetic sensor, and said corrected offset is stored in said fuse memory.

3. A geomagnetic sensor correction method for correcting the measurement values of a geomagnetic sensor according to claim 1, which possesses a step in which correction of measurement values is conducted based on measurement values in a zero magnetic field at the time of manufacture of said geomagnetic sensor.

4. A temperature sensor comprising:

a temperature detection unit for detecting temperature;

a fuse memory possessing a plurality of memory units, which enables a selective electrical cut-off or connection of each of said memory units, for storing prescribed data according to a state of the electrical cut-off or connection;

a correction data writing unit for inputting measurement values of said temperature detection unit at a time of manufacture, for obtaining initial values that correct the measurement values of said temperature detection unit based on said measurement values, for obtaining correction values that correct a temperature property of said temperature detection unit based on said measurement values, and for writing said initial values and said correction values into said fuse memory by conducting selective electrical cut-off or connection of each memory unit contained in said fuse memory according to said initial values and said correction values;

a correction data reading unit for reading said initial values and correction values from said fuse memory at times of actual use after manufacture; and

a correction unit for inputting the measurement values of said temperature detection unit at times of actual use, and for correcting the measurement values of said temperature detection unit based on the initial values and correction values read by said correction data reading unit.

5. A temperature sensor correction method for correcting measurement data in a temperature sensor comprising a temperature detection unit for detecting temperature, a control unit for processing measurement values of said temperature detection unit, and a fuse memory for enabling a selective electrical cut-off by a flow of electric current, and for storing correction data used in correction by said correction unit according to a state of the electrical cut-off, the temperature sensor correction method comprising:

a step in which the measurement values of said temperature detection unit are inputted by said control unit at a time of manufacture, initial values that correct a variation in measurement values of said temperature detection unit are obtained based on said measurement values, correction values that correct a variation in sensitivity of said temperature detection unit are obtained based on said measurement values, and said initial values and said correction values are written into said fuse memory by conducting an electrical cut-off of said fuse memory according to said initial values and said correction values;

a step in which said initial values and correction values are read from said fuse memory by said control unit at times of actual use after manufacture; and

a step in which the measurement values of said temperature detection unit are inputted by said control unit at said times of actual use, and the measurement values of said temperature detection unit are corrected based on the initial values and correction values read by said correction data reading unit.

6. A temperature sensor correction method according to claim 5, wherein the aforementioned correction data writing step comprises:

processing that subtracts a preset logic value pertaining to a first temperature of the temperature detection unit from the measurement value pertaining to the first temperature of said temperature detection unit, and calculates said correction value;

processing that divides the value obtained by subtracting the measurement value pertaining to the first temperature of said temperature detection unit from the measurement value pertaining to a second temperature of said temperature detection unit by the value obtained by subtracting said first temperature from said second temperature; and

processing that writes said initial values and said correction values into said fuse memory by a selective electrical cut-off or connection of each memory unit contained in said fuse memory according to said initial values and said correction values.

7. A geomagnetism detection device comprising a geomagnetism detection element for detecting transverse axial components of geomagnetism and a nonvolatile memory element of a thermal metamorphic type for storing correction information of detection outputs of the pertinent geomagnetism detection element, wherein said correction information consists of axial sensitivity correction coefficients and interaxial correction coefficients as well as values expressed as ratios relative to an axial sensitivity correction coefficient of either axis.

8. A geomagnetism detection device according to claim 7, wherein said nonvolatile memory element stores a minimum amount of correction information pertaining to axial sensitivity correction coefficients other than said axial sensitivity correction coefficient of either axis.

9. A geomagnetism detection device according to claim 8, which uses a differential value obtained by subtracting a preset standard value from a ratio of the pertinent axial sensitivity correction coefficient relative to an axial sensitivity correction coefficient, as correction information pertaining to an axial sensitivity correction coefficient other than said axial sensitivity correction coefficient of either axis.

10. A geomagnetism detection device according to claim 7 to claim 9 provided with a correction computation circuit for conducting correction computation of the detection output of said geomagnetism detection element, wherein this correction computation circuit multiplies the axial sensitivity correction coefficient by the detection output to conduct correction, and adds to it a correction term obtained by multiplying the axial sensitivity correction coefficient by the detection output of the other axis.

11. A geomagnetism detection device according to claim 10 provided with a correction computation circuit for conducting correction computation of the detection outputs of said geomagnetism detection element, wherein this correction computation circuit conducts correction computation after adding said standard value to said differential value, and restoring the axial sensitivity correction coefficient.

12. A geomagnetism detection device according to claim 10, wherein said correction computation circuit conducts computation by substituting a preset alternate value for correction coefficients that are unobtainable from said correction data.

20. A geomagnetism detection device according to claim 8 provided with a correction computation circuit for conducting correction computation of the detection output of said geomagnetism detection element, wherein this correction computation circuit multiplies the axial sensitivity correction coefficient by the detection output to conduct correction, and adds to it a correction term obtained by multiplying the axial sensitivity correction coefficient by the detection output of the other axis.

21. A geomagnetism detection device according to claim 9 provided with a correction computation circuit for conducting correction computation of the detection output of said geomagnetism detection element, wherein this correction computation circuit multiplies the axial sensitivity correction coefficient by the detection output to conduct correction, and adds to it a correction term obtained by multiplying the axial sensitivity correction coefficient by the detection output of the other axis.

22. A geomagnetism detection device according to claim 11, wherein said correction computation circuit conducts computation by substituting a preset alternate value for correction coefficients that are unobtainable from said correction data.

13. A geomagnetism detection device comprising:

a geomagnetism detection element for detecting geomagnetism of each transverse axial component; and

a nonvolatile memory element of a thermal metamorphic type for storing one piece or a plurality of pieces of correction data for correcting said detected geomagnetism values,

wherein each piece of said correction data is expressed as a value of a ratio of an axial sensitivity correction coefficient, or interaxial correction coefficient, or a differential value obtained by subtracting a preset standard value from an axial sensitivity correction coefficient relative to the axial sensitivity correction coefficient of either axis.

14. A geomagnetism detection device according to claim 13, wherein at least one piece of said correction data is a value of the ratio of an axial sensitivity correction coefficient other than one pertaining to said either axis relative to the axial sensitivity correction coefficient of said either axis.

15. A geomagnetism detection device according to claim 13, wherein at least one piece of said correction data is a value of the ratio of a differential value obtained by subtracting a prescribed standard value from an axial sensitivity correction coefficient pertaining to other than either of said axes, relative to said axial sensitivity correction coefficient of either axis.

16. A geomagnetism detection device according to claim 13 provided with a correction computation circuit for correcting the values of geomagnetism for each transverse axial component detected by said geomagnetism detection element,

wherein said correction computation circuit obtains a corrected geomagnetism value by computing the sum of a multiplication value obtained by multiplying the geomagnetism value of a specified axial component by an addition value obtained by adding a prescribed value to the ratio of the axial sensitivity correction coefficient of said specified axial component, or of a differential value obtained by subtracting a prescribed standard value from the axial sensitivity correction coefficient of said specified axial component, relative to said axial sensitivity correction coefficient of either axis, and a multiplication value obtained by multiplying the geomagnetism value of the other axial component by the value of the ratio of said interaxial correction coefficient relative to the axial sensitivity correction coefficient of either of said axial components.

17. A geomagnetism detection device according to claim 13 provided with a correction computation circuit for correcting the values of geomagnetism for each transverse axial component detected by said geomagnetism detection element,

wherein said correction computation circuit obtains a corrected geomagnetism value by calculating a multiplication value obtained by multiplying the geomagnetism value of a specified axial component by an addition value obtained by adding a prescribed value to the ratio of the axial sensitivity correction coefficient of said specified axial component, or of a differential value obtained by subtracting a prescribed standard value from the axial sensitivity correction coefficient of said specified axial component, relative to said axial sensitivity correction coefficient of either axis.

18. A geomagnetism detection device according to claim 13, wherein said nonvolatile memory element of the thermal metamorphic type is a fuse memory.

19. A geomagnetism detection device according to claim 13, wherein said prescribed standard value is said axial sensitivity correction coefficient of either axis.