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Method of and apparatus for measuring properties of an object with acoustically induced electromagnetic waves

Foreign code F150008500
File No. B15-03EP1
Posted date Nov 5, 2015
Country EPO
Application number 13164251
Gazette No. 2630912
Gazette No. 2630912
Date of filing Aug 14, 2006
Gazette Date Aug 28, 2013
Gazette Date Jul 29, 2015
Priority data
  • P2005-325064 (Nov 9, 2005) JP
  • 06796418 (Aug 14, 2006) EP
Title Method of and apparatus for measuring properties of an object with acoustically induced electromagnetic waves
Abstract A measuring method and apparatus in which a measurable object (23) is irradiated with acoustically induced electromagnetic waves to measure an electric property from one or more characteristics selected from the group which consists of intensity, phase, and frequency characteristics of said electromagnetic waves.
The electric property of said measurable object (23) includes a change or changes in one or more of property values selected from the group which consists of electric field, dielectric constant, and spatial gradient of electric field or spatial gradient of dielectric constant of said measurable object; and concentration, mass, size, shape, and number of charges of charged particles which said measurable object (23) possesses; and interaction of said charged particles with a medium surrounding said charged particles.
Scope of claims [claim1]
1. An apparatus (21) for measuring a property of an object (23) with acoustically induced electromagnetic waves, characterized in that it comprises: an acoustic generator (25) for emitting an acoustic wave pulse (26) towards a measurable object (23); an anechoic chamber (22); a retainer table (24) for holding said object (23) disposed in said anechoic chamber (22) ; an antenna or coil (28) for receiving electromagnetic waves generated from a part (23a) of said measurable object (23) which is irradiated with said acoustic wave pulse (26) emitted by said acoustic generator (25); and a control, measure, and process unit (29, 30, 50, 52, 60, 65, 75, 76) for driving and controlling said acoustic generator (25) and for measuring and processing said electromagnetic waves received by said antenna or coil (28) so as to measure an electric property from one or more characteristics selected from the group which consists of intensity, phase, and frequency characteristics of said electromagnetic waves, the electric property of said measurable object (23) including a change or changes in one or more of property values selected from the group which consists of electric field, dielectric constant, and spatial gradient of electric field or spatial gradient of dielectric constant of said measurable object; and concentration, mass, size, shape, and number of charges of charged particles which said measurable obj ect possesses; and interaction of said charged particles with a medium surrounding said charged particles; characterised in that a time period for said acoustic wave pulse (26) to travel over a distance (d) between said acoustic generator (25) and said object (23) is longer than a duration of electromagnetic trailing noises produced by said acoustic generator (25).
[claim2]
2. An apparatus according to claim 1, wherein
said acoustic generator (25) comprises a plurality of acoustic generators or a plurality of acoustic generators fixed on a concaved surface whose normal is focused on a point, whereby acoustic wave pulses generated from said acoustic generators are controlled of their mutual phase by said control, measure, and process unit so as to be focused on a desired position of said measurable object (23), and
the focusing position of acoustic wave pulses is scanned over a two-dimensional surface or three-dimensional volume of said measurable object (23) or said acoustic generators are scanned mechanically around said measurable object (23) to scan the focusing position of acoustic wave pulses over a two-dimensional surface or three-dimensional volume of said measurable object (23).
[claim3]
3. An apparatus according to claim 1, wherein
said control, measure, and process unit includes means by which said electromagnetic waves received by said antenna or coil (28) are heterodyne- or phase-detected with a frequency of said acoustic wave pulses, and means by which an electromagnetic wave signal so detected is locked in with a pulse period frequency of said acoustic wave pulses and thereby detected.
[claim4]
4. An apparatus according to claim 1, wherein
said control, measure, and process unit comprises means for causing broadband ultrashort pulses to be generated from said acoustic generator (25), and means for measuring a frequency of said electromagnetic waves received by said antenna or coil (28).
[claim5]
5. An apparatus according to any one of claims 1 to 4, wherein
said measurable object (23) is a nervous tissue representative of a brain or a muscle tissue of a living body,
said electric property is a charge distribution formed when neuron is activated, or a charge distribution formed when the muscle tissue is activated, and
a site of said activated neuron or a site of said activated muscle tissue is identified by said electric property.
[claim6]
6. An apparatus according to any one of claims 1 to S, wherein
said control, measure, and process unit includes a SQUID for detecting a magnetic field.
[claim7]
7. A method of measuring a property of an object (23) with acoustically induced electromagnetic waves comprising the steps of: irradiating a measurable object (23) with an acoustic wave pulse (26); receiving electromagnetic waves (27) generated from a part (23a) of said measurable object (23) which is irradiated with said acoustic wave pulse;, and measuring an electric property from one or more characteristics selected from the group which consists of intensity, phase, and frequency characteristics of said electromagnetic waves, the electric property of said measurable object including a change or changes in one or more of property values selected from the group which consists of electric field, dielectric constant, and spatial gradient of electric field or spatial gradient of dielectric constant of said measurable obj ect; and concentration, mass, size, shape, and number of charges of charged particles which said measurable obj ect possesses; and interaction of said charged particles with a medium surrounding said charged particles; characterized in that a time period for said acoustic wave pulse to travel over a distance (d) between a source of emission (25) of said acoustic wave pulse and said object (23) is longer than a duration of electromagnetic trailing noises produced by said emission source (25);
[claim8]
8. A method according to claim 7, wherein
the electromagnetic waves are measured of time dependence of their intensity detected subsequent to irradiation with said acoustic wave pulses to determine a relaxation characteristic of a property value for charged particles which said measurable object (23) possesses.
[claim9]
9. A method according to claim 7, wherein
said measurable object (23) is irradiated with said acoustic wave pulses so that a time period for said acoustic wave pulses to propagate over the distance (d) between said emission source (25) and said measurable object (23) is longer than a pulse duration of said acoustic wave pulses, and
said electromagnetic waves generated from said measurable object (23) are received by separating in time signals of said electromagnetic waves generated from said measurable object (23) from electromagnetic noises generated by the emission source (25) of said acoustic wave pulses.
[claim10]
10. A method according to any one of claims 7 to 9, wherein
said measurable object (23) is irradiated with acoustic wave pulses by focusing acoustic wave pulses from a plurality of sources of the acoustic wave pulses on a desired small part of the object (23), and
electromagnetic waves induced at said small part are measured with an antenna or coil (28) disposed to surround said object (23) whereby acoustic wave pulses are focused on a desired part and on the desired part from a desired direction, and electromagnetic waves radiated from a desired position and from the desired positions towards a desired direction are measured while their radiation bearing distribution is determined.
[claim11]
11. A method according to claim 10, wherein
said focusing of acoustic wave pulses is scanned over a two-dimensional surface or three-dimensional volume of said measurable object (23), and
an intensity of induced electromagnetic waves at each scanning position is measured using an antenna or coil (28) surrounding said measurable object (23) to determine a two-dimensional or three-dimensional distribution of changes in a property value of charged particles of said measurable object (23) by comparing said scanning position with the measured intensity of the electromagnetic waves.
[claim12]
12. A method according to claim 7 or claim 8, wherein
said acoustic wave pulses are applied in the form of broadband ultrashort pulses composed of a plurality of frequency components,
the frequency of said electromagnetic waves is measured, and
from the measured frequency of said electromagnetic waves, information is derived on depthwise position of charged particles generating the electromagnetic waves.
  • Applicant
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • Inventor
  • IKUSHIMA KENJI
  • KOMIYAMA SUSUMU
IPC(International Patent Classification)
Specified countries Contracting States: DE
Reference ( R and D project ) SORST Selected in Fiscal 2001
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