MANUAL AND AUTOMATIC PROBE CALIBRATION

• US 20010020123A1
• Filed: 11/30/1999
• Published: 09/06/2001
• Est. Priority Date: 06/07/1995
• Status: Active Grant

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: DIAB, MOHAMED KHEIR, KIANI-AZARBAYJANY, ESMAIEL, LEPPER, JAMES M. Jr., RAGSDALE, CHARLES ROBERT
• Granted Patent: US 6,397,091 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: G01J 2003/2866 Markers; Calibrating of scan
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0254 Spectrometers, other than colorimeters, making use of an integrating sphere
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/0275 making use of sensor-related data, e.g. for identification of sensor parts or optical elements
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01N 2021/3144 for oxymetry
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 21/3151 using two sources of radiation of different wavelengths G01N21/33 - G01N21/39 take precedence
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G01N 2201/0627 : Use of several LED's for spectral resolution

Abstract

The method and apparatus of the present invention provides a system wherein light-emitting diodes (LEDs) can be tuned within a given range by selecting their operating drive current in order to obtain a precise wavelength. The present invention further provides a manner in which to calibrate and utilize an LED probe, such that the shift in wavelength for a known change in drive current is a known quantity. In general, the principle of wavelength shift for current drive changes for LEDs is utilized in order to allow better calibration and added flexibility in the use of LED sensors, particularly in applications when the precise wavelength is needed in order to obtain accurate measurements. The present invention also provides a system in which it is not necessary to know precise wavelengths of LEDs where precise wavelengths were needed in the past. Finally, the present invention provides a method and apparatus for determining the operating wavelength of a light emitting element such as a light emitting diode.

Claims

1. An medical sensor comprising:

a light emitting element configured to generate light of a selected wavelength, said light emitting element in communication with a first signal line;

an information element, said information element in communication with said first signal line; and

a detector responsive to light which originated from said light emitting element.

2. The medical sensor of

claim 1

, wherein said light emitting element is activated by a signal on said first signal line.

3. The medical sensor of

claim 2

, wherein said light emitting element is active with a signal on said first signal line at or above a first voltage level.

4. The medical sensor of

claim 3

, wherein said information element is configured to provide information on said first signal line when a voltage level below said first voltage level is present on said first signal line.

5. The medical sensor of

claim 4

, wherein said information element is coupled in parallel with said light emitting element.

6. The medical sensor of

claim 4

, wherein said sensor comprises an oximeter sensor.

7. The medical sensor of

claim 1

, wherein said information element is an impedance network.

8. The medical sensor of

claim 1

, wherein said information element is a memory device.

9. The medical sensor of

claim 1

, wherein said information element is a resistor.

10. The medical sensor of

claim 1

, wherein said information indicates the selected wavelength value.

11. The medical sensor of

claim 1

, wherein medical sensor is an oximeter sensor, said information element indicates that the medical sensor is of a predetermined type.

12. The oximeter sensor of

claim 11

, wherein said information element is a security element which indicates that the medical sensor is an authorized sensor.

13. An oximeter sensor comprising:

a first signal line;

a light emitting element configured to generate light of a selected wavelength, said light emitting element in communication with said first signal line for receiving a drive current;

an information element having information about said oximeter sensor, said information element in communication with said first signal line, said information element adapted to provide said information on said first signal line; and

a detector responsive to light which originated from said light emitting element.

14. The oximeter sensor of

claim 13

, wherein said light emitting element is activated by a signal on said first signal line.

15. The oximeter sensor of

claim 14

, wherein said light emitting element is active with a signal on said first signal line at or above a first voltage level.

16. The oximeter sensor of

claim 15

, wherein said information element is configured to provide information on said first signal line when a voltage level below said first voltage level is present on said first signal line.

17. The oximeter sensor of

claim 16

, wherein said information element is coupled in parallel with said light emitting element.

18. The oximeter sensor of

claim 13

, wherein said information element is an impedance network.

19. The oximeter sensor of

claim 13

, wherein said information element is a memory device.

20. The oximeter sensor of

claim 13

, wherein said information element is a resistor.

21. The oximeter sensor of

claim 13

, wherein said information indicates the selected wavelength value.

22. The oximeter sensor of

claim 13

, wherein said information element indicates that the medical sensor is of a predetermined type.

23. The oximeter sensor of

claim 22

, wherein said information element is a security element which indicates that the medical sensor is an authorized sensor.

24. A medical monitor comprising:

a sensor comprising;

a first signal line;

a light emitting element configured to generate light of a selected wavelength, said light emitting element associated with said first signal line for receiving a drive current; and

an information element having information about said oximeter sensor, said information element adapted to provide said information on said first signal line; and

a detector responsive to light which originated from said light emitting element; and

a processor in communication with said first signal line and in communication with said detector, said processor responsive to information on said first signal line from said information element and providing control for said light emitting element via said first signal line.

25. The medical monitor of

claim 24

, wherein said processor comprises an oximeter processor.

26. The medical monitor of

claim 24

, wherein said information is indicative of the selected wavelength of said light emitting element.

27. The medical monitor of

claim 24

, wherein said information is indicative of the type of said sensor.

28. The medical monitor of

claim 25

, wherein said information is indicative of the company that provides said sensor.

29. The medical monitor of

claim 25

, wherein said light emitting element is active at or above a first voltage level and inactive below said first voltage level.

30. The medical monitor of

claim 29

, wherein said information element is configured to provide said information on said first signal line when a voltage level below said first voltage level is present on said first signal line.

31. The medical monitor of

claim 24

, wherein said information element is an impedance network.

32. The medical monitor of

claim 24

, wherein said information element is a memory device.

33. The medical monitor of

claim 24

, wherein said information element is a resistor.

34. An identification system for a medical sensor for use with a medical monitor, the medical monitor having a first signal line which provides control for said medical sensor and which receives information about said medical sensor, said medical sensor having a light emitting element configured to receive control signals on said first signal line, said identification system comprising:

an information element coupled to said first signal line, said information element configured to provide information to said medical monitor on said first signal line.

35. The identification system of

claim 35

, and wherein said light emitting element is active at or above a first voltage and inactive below said first voltage, said information element responsive to a voltage below said first voltage to provide said information on said first signal line.

36. The identification system of

claim 36

, wherein said light emitting element is responsive to a voltage at or above said first voltage on said first signal line to emit light of a selected wavelength.

37. The identification system of

claim 37

, wherein said information is information about said selected wavelength.

38. The identification system of

claim 37

, wherein said information is indicative of the type of the medical sensor.

39. The identification system of

claim 37

, wherein said medical sensor is an oximeter sensor.

40. The identification system of

claim 40

, wherein said information element is an impedance element.

41. The identification system of

claim 41

, wherein said information element is a resistor.