Measuring apparatus using an ultrasonic wave to provide flaking state detection for a specimen on the basis of freqency analysis of a wave reflected by the specimen

• US 5,351,544 A
• Filed: 11/18/1991
• Issued: 10/04/1994
• Est. Priority Date: 11/21/1990
• Status: Expired due to Fees

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Endo, Tomio, Aoki, Masahiro, Yamagishi, Takeshi
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MILLER, ROSE MARY
• Application Number:
  US07/793,615
• Time in Patent Office: 1,051 Days
• Field of Search: 73/602, 73/606, 73/588, 73/630, 73/609, 73/613
• US Class Current: 73/588
• CPC Class Codes: G01N 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/2697 Wafer or (micro)electronic parts
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/343 pulse waves, e.g. particular sequence of pulses, bursts
• CPC Class Codes: G01N 29/4454 Signal recognition, e.g. specific values or portions, signal events, signatures

Abstract

A measuring apparatus using an ultrasonic wave according to the invention transmits an ultrasonic wave pulse into a specimen, receives the echo reflected by the specimen and converts it into an electric signal. The components of the electric signal that represent the wave reflected by the specimen and contain data on the state of the specimen are extracted by a gate circuit. The components obtained by the gate circuit are converted into a power spectrum by a circuit for performing a Fourier transformation. The thickness of the specimen and/or the flaking state of the specimen can be determined from this power spectrum.

Claims

1. A measuring apparatus using an ultrasonic wave, comprising:

ultrasonic wave transmission/reception means for transmitting an ultrasonic wave pulse into a specimen, for receiving an echo wave from the specimen and for converting the echo wave, including reflected components reflected by the specimen, into an electric signal;

extracting means for extracting reflected signal components corresponding to the reflected components from the electric signal;

spectrum detecting means for detecting a power spectrum of the reflected signal components, extracted by said extracting means, on the basis of a Fourier-transformation; and

flaking detecting means for detecting peaks and troughs of the power spectrum, and for then detecting a flaking of the specimen in accordance with a cycle of the peaks and troughs of the power spectrum that is detected.

2. A measuring apparatus using an ultrasonic wave, comprising:

ultrasonic wave transmission/reception means for transmitting an ultrasonic wave pulse into a specimen, for receiving an echo wave from the specimen and for converting the echo wave, including reflected components reflected by the specimen, into an electric signal;

extracting means for extracting reflected signal components corresponding to the reflected components from the electric signal;

spectrum detecting means for detecting a power spectrum of the reflected signal components extracted by said extracting means; and

state detecting means for determining a state of the specimen along a depth thereof according to a frequency cycle of said power spectrum, said state detecting means including first differentiation means for differentiating said power spectrum, and flaking state determining means for determining a flaking state of the specimen according to a differentiation result of said first differentiation means.

3. An apparatus according to claim 2, wherein said flaking state determining means includes comparing means for comparing the differentiation result with a preset threshold value to determine the flaking state of said specimen.

4. An apparatus according to claim 3, wherein said comparing means outputs a detection signal for indicating an existence of a flaking portion in the specimen when the differentiation result is smaller than said threshold value.

5. An apparatus according to claim 4, wherein it further comprises:

scanning means for scanning said specimen by said ultrasonic wave pulse;

A/D conversion means for converting the reflected signal components extracted by said extracting means to digital data;

image memory means for storing the digital data representing the reflected signal components as ultrasonic wave image data for said specimen; and

display means for displaying said ultrasonic wave image data stored in said image memory means and data corresponding to the flaking state determined by said flaking state determining means.

6. A measuring apparatus using an ultrasonic wave, comprising:

ultrasonic wave transmission/reception means for transmitting an ultrasonic wave pulse into a specimen, for receiving an echo wave from the specimen and for converting the echo wave, including reflected components reflected by the specimen, into an electric signal;

extracting means for extracting reflected signal components corresponding to the reflected components from the electric signal;

spectrum detecting means for detecting a power spectrum of the reflected signal components extracted by said extracting means; and

state detecting means for determining a state of the specimen along a depth thereof according to a frequency cycle of said power spectrum, said state detecting means including characteristics detecting means for detecting frequency characteristics of said power spectrum detected by said spectrum detecting means which correspond to the frequency cycle and means for determining a thickness of the specimen as the state of the specimen along the depth thereof according to said frequency characteristics detected by said characteristics detecting means and a sonic velocity in said specimen.

7. An apparatus according to claim 6, wherein said characteristics detecting means includes differentiation means for differentiating said power spectrum to detect said frequency characteristics of said power spectrum.

8. An apparatus according to claim 6, wherein said characteristics detecting means includes Fourier transformation means for Fourier-transforming said power spectrum to detect said frequency characteristics of said power spectrum.

9. An apparatus according to claim 6, wherein said ultrasonic wave transmission/reception means includes an acoustic lens for converging said ultrasonic wave pulse to a spot on the specimen.

10. An apparatus according to claim 9, wherein said ultrasonic wave transmission/reception means further includes pulse transmission means for generating a pulse transmission signal and a transducer for converting said transmission signal coming from said pulse transmission means into an ultrasonic wave pulse, introducing it into said acoustic lens and converting the echo wave reflected by said specimen and received by said acoustic lens into said electric signal.

11. A measuring apparatus using an ultrasonic wave, comprising:

ultrasonic wave transmission/reception means for transmitting an ultrasonic wave pulse into a specimen, for receiving an echo wave from the specimen and for converting the echo wave, including reflected components reflected by the specimen, into an electric signal;

extracting means for extracting reflected signal components corresponding to the reflected components from the electric signal;

spectrum detecting means for detecting a power spectrum of the reflected signal components extracted by said extracting means;

state detecting means for determining a state of the specimen along a depth thereof according to a frequency cycle of said power spectrum;

detecting means for detecting envelopes in the reflected signal components extracted by said extracting means; and

time-width determining means for measuring a time-width of an envelope detection signal obtained by said detecting means; and

said state detecting means includes means for determining a flaking state of said specimen from said time-width.