JPH071253B2 - Ultrasonic detector - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an ultrasonic detection device for obtaining internal information of a substance by measuring a change of the substance surface caused by ultrasonic waves.

[Prior art]

Conventionally, there is an ultrasonic microscope as a non-destructive apparatus for observing the inside of a material. As shown in FIG. 2, this ultrasonic microscope 1 focuses ultrasonic waves generated by applying an electric signal of several 100 MHz to several GHz to a transducer 2 by means of an acoustic lens 3, and the surface of the DUT 4 is measured. Is to be incident on. At this time, the ultrasonic wave is reflected / scattered on the surface of the DUT 4, and the surface information of the DUT 4 can be obtained by converting the ultrasonic wave returning to the transducer 1 into an electric signal. FIG. 3 shows a conventional scanning acoustic microscope 5. In this scanning ultrasonic microscope 5, the transducer 2 is brought into close contact with the back side of the DUT 4 via the liquid 6, and
Ultrasonic waves are applied to the laser beam 7 on the surface of the DUT 4 opposite to the transducer 2 and the mirror 8A.
The reflected wave from the surface of the DUT 4 is extracted via the lens 9 and the mirror 8B. At this time, ultrasonic waves are scattered and diffracted due to defects inside the DUT 4, which changes the surface state of the DUT 4, and the surface of the DUT 4 is changed by the mirror 8A.
It is possible to know the state inside the DUT 4 by deflecting and scanning.

[Problems to be Solved by the Invention]

The conventional ultrasonic microscope 1 shown in FIG. 2 has to move by moving the DUT 4 and the acoustic lens 3 relative to each other, and in the case of the scanning ultrasonic microscope 5 shown in FIG. However, since the mirror 8A deflects and scans the laser beam, there is a problem that real-time observation is impossible. The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an ultrasonic detection device capable of obtaining internal information of an object to be measured in real time.

[Means for Solving the Problems]

The present invention is a vibrating means for ultrasonically vibrating an object to be measured,
A mirror attached to the surface to be measured of the object to be measured, a light source for irradiating the mirror, an image forming system for forming an image of the light from the light source reflected by the mirror, and the image forming system. The above object is achieved by constructing an ultrasonic detection device including an image sensor arranged in a plane orthogonal to the reflection optical axis at the image forming position of the mirror. Further, in the ultrasonic wave detecting device, the above-mentioned object is achieved by arranging, in the image forming system, a 0th-order light cutting means for cutting a 0th-order light component in the reflected light from the mirror.

[Action and effect]

In the present invention, since the image sensor is provided at the image forming position of the reflected light from the surface of the object to be ultrasonically vibrated, the two-dimensional distribution of the ultrasonic waves reflected on the surface of the object to be measured can be known in real time. In addition, it is possible to perform nondestructive measurement inside the object to be measured.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. The ultrasonic detection device 10 according to the embodiment of the present invention is the object to be measured 12
A transducer 14 attached to the back surface (lower surface in the figure) of the DUT 12 for ultrasonically vibrating,
On the upper surface 12A of the DUT 12 in the drawing, the liquid 1
6, a glass plate 20 mounted in parallel with the surface 12A and having a mirror 18 formed on the liquid 16 side, and a half mirror 22 from the surface side of the glass plate 20 to the mirror 18. Laser light source 24 for irradiating the laser light with a laser beam, an image forming system 26 for forming an image of the scattered light reflected and scattered by the mirror 18 from the laser light source 24, and the image forming system 26 The image sensor 28 is arranged in a plane orthogonal to the reflected optical axis at the image forming position of the mirror 18. The imaging system 26 includes the half mirror 22 and an image sensor.
A lens 30 and a knife edge 32 are disposed between the lens 30 and the half mirror 22 from the half mirror 22 side. The knife edge 32 is focused by a lens 30,
It is arranged at the position of the focal point 34 of the reflected light from the mirror 18,
Next light, that is, straight light is cut off so that only scattered light reaches the image sensor 28. The liquid 16 interposed between the DUT 12 and the transducer 14 is for acoustically coupling the two and reducing the reflection of ultrasonic waves. Next, the operation of the apparatus of the above embodiment will be described. When the object to be measured 12 is ultrasonically vibrated by the transducer 14, the ultrasonic wave propagates through the liquid 16 and reaches the mirror 18 of the glass plate 20. If there is a defect or the like inside the DUT 12, the propagated ultrasonic waves scatter and diffract there, and as a result, the surface state of the surface 12A of the DUT 12 is changed. Since the glass plate 20 is acoustically coupled to the DUT 12 through the liquid 16, the two-dimensional intensity of the ultrasonic waves incident on the glass plate 20 is a defect inside the DUT 12. And so on. Therefore, by being excited by ultrasonic waves, the mirror 18
Fine irregularities corresponding to the internal information of the object to be measured 12 are generated on the surface of the. The laser light emitted from the laser light source 24, reflected by the half mirror 22, transmitted through the glass plate 20, and reaches the mirror 18 is scattered by the fine unevenness formed on the mirror 18. The laser light scattered and reflected by the mirror 18 passes through the half mirror 22, is condensed by the lens 30, and forms an image on the image sensor 28. At this time, the straight-advancing light is blocked by the knife edge 32 arranged at the converging point 34, and only the scattered light reaches the image sensor 28. The image of the mirror surface formed on the image sensor 28 is
It corresponds to the fine irregularities on the surface of the mirror 18. In other words, an image corresponding to the ultrasonic intensity distribution on the surface of the mirror 18 can be formed. Therefore, by reading this image two-dimensionally by the image sensor 28, the glass plate
It is possible to measure the two-dimensional intensity of ultrasonic waves incident on 20. Therefore, in this embodiment, the internal information of the DUT 12 can be two-dimensionally observed in real time by the image sensor 28 without scanning the laser beam. In the above embodiment, the knife edge 32 is used as a means for cutting the 0th-order light, but this cuts the straight light to leave only the scattered light, so that the image contrast on the image sensor 28 is improved. This is an improvement, and other 0th-order light cutting means may be provided. For example,
There are spatial filters, etc. Further, if the contrast of the image on the image sensor 28 is such that the 0th order light cutting means need not be provided, it is not necessary to provide the 0th order light cutting means such as a knife edge. Further, in the above-described embodiment, the DUT 12 is adapted to be ultrasonically vibrated by the transducer 14. However, if this is required, the DUT 12 can be ultrasonically vibrated. Therefore, the oscillating means may also be used to oscillate the object to be measured 12 with ultrasonic waves by irradiating the object to be measured 12 with a light pulse.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an ultrasonic detecting apparatus according to the present invention, FIG. 2 is a perspective view showing an outline of a conventional ultrasonic microscope, and FIG. 3 is an outline of yet another conventional ultrasonic microscope. FIG. 10 ... Ultrasonic wave detector, 12 ... Object to be measured, 12A ... Surface, 14 ... Transducer, 18 ... Mirror, 24 ... Laser light source, 26 ... Imaging system, 28 ... Image sensor, 32 …
… Knife edge.

Claims (2)

[Claims] 1. Exciting means for ultrasonically vibrating an object to be measured,
A mirror attached to the surface to be measured of the object to be measured, a light source for irradiating the mirror, an image forming system for forming an image of the light from the light source reflected by the mirror, and the image forming system. And an image sensor arranged in a plane orthogonal to the reflection optical axis at the image forming position of the mirror. 2. The ultrasonic detecting apparatus according to claim 1, wherein the image forming system is provided with 0th-order light cutting means for cutting a 0th-order light component in reflected light from the mirror.