Defect detection device and defect detection method

A defect detection method for detecting a defect of an inspection target, the defect detection method comprising:

• a static image obtaining step, irradiating the inspection target with coherent light, imaging the inspection target by using a camera, and obtaining an image when the inspection target is static;
• an ultrasonically vibrated image obtaining step, ultrasonically vibrating the inspection target by using an ultrasonic vibration device while irradiating the inspection target with the coherent light, imaging the inspection target by using the camera, and obtaining an image when the inspection target is ultrasonically vibrated;
• and
• a defect detection step, detecting the defect of the inspection target based on a deviation between the image when the inspection target is static and the image when the inspection target is ultrasonically vibrated that are obtained by the camera,
• wherein in the static image obtaining step, an image comprising an interference pattern at a time of being static generated through interference of the coherent light reflected by a surface of the inspection target is obtained,
• in the ultrasonically vibrated image obtaining step, an exposure time of the camera is set longer than a period of ultrasonic vibration of the inspection target, and an image comprising an interference pattern at a time of ultrasonic vibration generated through interference of the coherent light reflected by the surface of the inspection target is obtained by using the camera, and
• in the defect detection step, a vibration occurrence pixel is specified based on a deviation between an image comprising an interference pattern when the inspection target is static and an image comprising an interference pattern when the inspection target is ultrasonically vibrated that are obtained by the camera, a region in which the vibration occurrence pixel that is specified is densely arranged in a predetermined number or more is set as a defective region, and the defect is detected.

A defect detection device, detecting a defect of an inspection target, the defect detection device comprising:

• an ultrasonic vibration device, ultrasonically vibrating the inspection target;
• a driving unit, supplying high frequency power to the ultrasonically vibration device;
• a current sensor, detecting a current of the high frequency power supplied from the driving unit to the ultrasonic vibration device;
• a control unit, adjusting a frequency of the high frequency power supplied from the driving unit to the ultrasonic vibration device;
• a coherent light source, irradiating the inspection target with coherent light;
• a camera, having an imaging element imaging the inspection target irradiated with the coherent light to obtain an image;
• and
• a detection unit, detecting the defect of the inspection target based on a deviation between an image at a time when the inspection target is static and an image at a time when the inspection target is ultrasonically vibrated that are obtained by using the camera,
• wherein when the detection unit detects the defect of the inspection target, the control unit changes the frequency of the high frequency power supplied from the driving unit to the ultrasonic vibration device, and when the frequency of the high frequency power is changed, the control unit adjusts a voltage of the high frequency power supplied from the driving unit to the ultrasonic vibration device, so that the current detected by the current sensor falls within a predetermined range.

A defect detection device, detecting a defect of an inspection target, the defect detection device comprising:

• an ultrasonic vibration device, ultrasonically vibrating the inspection target;
• a driving unit, supplying high frequency power to the ultrasonically vibration device;
• a control unit, adjusting a frequency of the high frequency power supplied from the driving unit to the ultrasonic vibration device;
• a coherent light source, irradiating the inspection target with coherent light;
• a camera, having an imaging element imaging the inspection target irradiated with the coherent light to obtain an image;
• and
• a detection unit, detecting the defect of the inspection target based on a deviation between an image at a time when the inspection target is static and an image at a time when the inspection target is ultrasonically vibrated that are obtained by using the camera,
• wherein the control unit comprises a map in which a change of a voltage of the high frequency power supplied from the driving unit to the ultrasonic vibration device with respect to the frequency of the high frequency power supplied from the driving unit to the ultrasonic vibration device is defined in advance, so that a current of the high frequency power supplied from the driving unit to the ultrasonic vibration device falls within a predetermined range, and
• when the frequency of the high frequency power supplied from the driving unit to the ultrasonic vibration device is changed, the voltage of the high frequency power supplied from the driving unit to the ultrasonic vibration device is adjusted based on the map.

A defect detection device, detecting a defect of an inspection target, the defect detection device comprising:

• an ultrasonic vibration device, formed by a plurality of ultrasonic speakers that are directive and disposed on a periphery of the inspection target, the ultrasonic speakers are installed to a casing, so as to concentrate a plurality of ultrasonic waves generated by the respective ultrasonic speakers on the inspection target, and ultrasonically vibrate the inspection target;
• a plurality of driving units, respectively supplying high frequency power to the ultrasonic speakers;
• a current sensor, each detecting a current of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers;
• a control unit, adjusting a frequency of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers,
• a coherent light source, irradiating the inspection target with coherent light;
• a camera, having an imaging element imaging the inspection target irradiated with the coherent light to obtain an image;
• and
• a detection unit, detecting the defect of the inspection target based on a deviation between an image at a time when the inspection target is static and an image at a time when the inspection target is ultrasonically vibrated that are imaged by using the camera,
• wherein when the detection unit detects the defect of the inspection target, the control unit changes the frequency of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers, and when the frequency of the high frequency power is changed, the control unit adjusts a voltage of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers, so that the current detected by each of the current sensors falls within a predetermined range.

A defect detection device, detecting a defect of an inspection target, the defect detection device comprising:

• an ultrasonic vibration device, formed by a plurality of ultrasonic speakers that are directive and disposed on a periphery of the inspection target, the ultrasonic speakers are installed to a casing, so as to concentrate a plurality of ultrasonic waves generated by the respective ultrasonic speakers on the inspection target, and ultrasonically vibrate the inspection target;
• a plurality of driving units, respectively supplying high frequency power to the ultrasonic speakers;
• a control unit, adjusting a frequency of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers,
• a coherent light source, irradiating the inspection target with coherent light;
• a camera, having an imaging element imaging the inspection target irradiated with the coherent light to obtain an image;
• and
• a detection unit, detecting the defect of the inspection target based on a deviation between an image at a time when the inspection target is static and an image at a time when the inspection target is ultrasonically vibrated that are imaged by using the camera,
• wherein the control unit comprises a map in which a change of a voltage of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers with respect to the frequency of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers is defined in advance, so that each current of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers falls within a predetermined range, and
• when the frequency of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers is changed, the voltage of the high frequency power supplied from each of the driving units to each of the ultrasonic speakers is adjusted based on the map.