Devices and method of measuring a mass

• US 7,140,255 B2
• Filed: 08/13/2004
• Issued: 11/28/2006
• Est. Priority Date: 08/19/2003
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Ishikawa, Seiji, Okada, Naotake, Ohsugi, Yukihisa
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US10/918,206
• Publication Number:
  US 20050039532A1
• Time in Patent Office: 837 Days
• Field of Search: 736/49, 73/18.2, 737/78, 738/01, 736/62, 735/70, 735/040.4, 735/041.2, 735/10
• US Class Current: 73/649
• CPC Class Codes: G01G 3/16 measuring variations of frequency of oscillations of the body
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/0426 Bulk waves, e.g. quartz crystal microbalance, torsional waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves

Abstract

A device 1 for measuring a mass comprises a vibrator 2, driving means 3A, 3B, 3C, 3D for exciting a basic vibration in the vibrator 2, detecting means 4A, 4B for detecting a displacement of vibration in the vibrator 2 and an adsorption film 5 capable of adsorbing a substance for detection. The mass is measured based on a difference between a detected value of the displacement of vibration obtained from the detecting means 4A, 4B when the mass is not measured and a detected value of the displacement of vibration obtained from the detecting means 4A, 4B when the mass is measured.

Claims

1. A device for measuring a mass of a substance, comprising a vibrator, a driving means for exciting a basic vibration in said vibrator, a detecting means for detecting a displacement of vibration in said vibrator, and an adsorption film capable of adsorbing a substance for detection,

wherein said mass of said substance adsorbed on said adsorption film is measured based on a difference between a detected value of said displacement of vibration obtained from said detecting means when said mass is not measured and a detected value of said displacement of vibration obtained from said detecting means when said mass is measured, and

wherein dislocation of said basic vibration is substantially symmetrical with respect to the central axis of said vibrator.

2. The device of claim 1, wherein said detected value from said detecting means is substantially zero when said mass is not measured.

3. The device of claim 1, wherein said basic vibration is of thickness-twist vibration mode of said vibrator.

4. The device of claim 1, wherein said vibrator comprises at least one pair of bending vibration arms, and wherein said basic vibration comprises bending vibration of said bending vibration arms.

5. A device for measuring a mass of a substance, comprising a vibrator, a driving means for exciting a basic vibration in said vibrator, a detecting means for detecting a displacement of vibration in said vibrator, and an adsorption film capable of adsorbing a substance for detection,

wherein said mass of said substance adsorbed on said adsorption film is measured based on a difference between a detected value of said displacement of vibration obtained from said detecting means when said mass is not measured and a detected value of said displacement of vibration obtained from said detecting means when said mass is measured,

wherein said driving means comprises a driving electrode and said detecting means comprises a detecting electrode, and

wherein a width “

L”

of said driving electrode is 0.2 times or more and 4.0 times or less of a width “

M”

of said detecting electrode.

6. The device of claim 5, wherein said detected value from said detecting means is substantially zero when said mass is not measured.

7. The device of claim 5, wherein said basic vibration is of thickness-twist vibration mode of said vibrator.

8. The device of claim 5, wherein said vibrator comprises at least one pair of bending vibration arms, and wherein said basic vibration comprises bending vibration of said bending vibration arms.

9. A device for measuring a mass of a substance, comprising a vibrator a driving means for exciting a basic vibration in said vibrator, a detecting means for detecting a displacement of vibration in said vibrator, and an adsorption film capable of adsorbing a substance for detection,

wherein said mass of said substance adsorbed on said adsorption film is measured based on a difference between a detected value of said displacement of vibration obtained said detecting means when said mass is not measured and a detected value of said displacement of vibration obtained from said detecting means when said mass is measured,

wherein said driving means comprises a driving electrode and said detecting means comprises a detecting electrode, and

wherein an area “

N”

of said driving electrode is 0.1 times or more and 3.0 times or less of an area “

O”

of said detecting electrode.

10. The device of claim 9, wherein said detected value from said detecting means is substantially zero when said mass is not measured.

11. The device of claim 9, wherein said basic vibration is of thickness-twist vibration mode of said vibrator.

12. The device of claim 9, wherein said vibrator comprises at least one pair of bending vibration arms, and wherein said basic vibration comprises bending vibration of said bending vibration arms.

13. A method of measuring a mass of a substance using a device for measuring a mass comprising a vibrator, a driving means for exciting a basic vibration in said vibrator, a detecting means for detecting a displacement of vibration in said vibrator, and an adsorption film capable of adsorbing a substance for detection:

said method comprising the step of;

obtaining said mass of said substances adsorbed on said adsorption film based on a difference between a detected value of said displacement of vibration obtained from said detecting means when said mass is not measured and a detected value of said displacement of vibration obtained from said detecting means when said mass is measured,

wherein dislocation of said basic vibration is substantially symmetrical with respect to the central axis of said vibrator.

14. The method of claim 13, wherein said detected value from said detecting means is substantially zero when said mass is not measured.

15. The method of claim 13, wherein said basic vibration is of thickness-twist vibration mode of said vibrator.

16. The method of claim 13, wherein said vibrator comprises at least one pair of bending vibration arms, and wherein said basic vibration comprises bending vibration of said bending vibration arms.

17. A method of measuring a mass of a substance using a device for measuring a mass comprising a vibrator, a driving means for exciting a basic vibration in said vibrator, a detecting means for detecting a displacement of vibration in said vibrator, and an adsorption film capable of adsorbing a substance for detection:

said method comprising the step of;

obtaining said mass of said substances adsorbed on said adsorption film based on a difference between a detected value of said displacement of vibration obtained from said detecting means when said mass is not measured and a detected value of said displacement of vibration obtained from said detecting means when said mass is measured,

wherein said driving means comprises a driving electrode and said detecting means comprises a detecting electrode, and

wherein a width “

L”

of said driving electrode is 0.2 times or more and 4.0 times or less of a width “

M”

of said detecting electrode.

18. The method of claim 17, wherein said detected value from said detecting means is substantially zero when said mass is not measured.

19. The method of claim 17, wherein said basic vibration is of thickness-twist vibration mode of said vibrator.

20. The method of claim 17, wherein said vibrator comprises at least one pair of bending vibration arms, and wherein said basic vibration comprises bending vibration of said bending vibration arms.

21. A method of measuring a mass of a substance using a device for measuring a mass comprising a vibrator, a driving means for exciting a basic vibration in said vibrator, a detecting means for detecting a displacement of vibration in said vibrator, and an adsorption film capable of adsorbing a substance for detection:

said method comprising the step of;

obtaining mass of said substances adsorbed on said adsorption film based on a difference between a detected value of said displacement of vibration obtained from said detecting means when said mass is not measured and a detected value of said displacement of vibration obtained from said detecting means when said mass is measured,

wherein said driving means comprises a driving electrode and said detecting means comprises a detecting electrode, and

wherein an area “

N”

of said driving electrode is 0.1 times or more and 3.0 times or less of an area “

O”

of said detecting electrode.

22. The method of claim 21, wherein said detected value from said detecting means is substantially zero when said mass is not measured.

23. The method of claim 21, wherein said basic vibration is of thickness-twist vibration mode of said vibrator.

24. The method of claim 21, wherein said vibrator comprises at least one pair of bending vibration arms, and wherein said basic vibration comprises bending vibration of said bending vibration arms.