Apparatus for ultrasonic examination

An apparatus for locating internal inhomogeneities in an otherwise homogeneous object, having a substantially plane or slightly curved surface, utilizing the pulse-echo method of ultrasonic examination comprising:

• a probe which can be guided freely in two-dimensional movement across the surface of the object and can be freely rotated about an axis which is at a right angle to the plane of the surface, wherein the probe transmits ultrasonic pulses and receives reflected ultrasonic pulses in a path forming a predetermined angle, other than 90.degree., with the surface;
• an ultrasonic circuit means coupled to the probe for producing and processing the ultrasonic pulses which are transmitted and received by the probe;
• an acoustic emitter means for producing an audible sound signal;
• a first control circuit means coupled to the ultrasonic circuit means and the acoustic emitter means for converting the received reflected ultrasonic pulses to a signal which continuously varies in intensity, frequency, or duration so that the acoustic emitter means produces an audible sound signal which varies in a continuous manner with the amplitude of the received reflected ultrasonic pulse;
• an elongated holder affixed to the probe;
• a positioned transducer slidably mounted on and movable relative to the holder in a direction along a straight line parallel to the projection of the pulse path on the surface;
• an indicating means mounted on the positioned transducer for indicating the point on the surface which represents the projection of the inhomogeneity on the surface;
• a two-position switch means for connecting the acoustic emitter means to said first control circuit means when said switch is in a first position;
• and
• a second control circuit means coupled to said acoustic emitter means when said switch means is in a second position, said second circuit means being coupled to said ultrasonic circuit means and said positioned transducer for converting the received reflected ultrasonic pulses to a signal which continuously varies in intensity, frequency, or duration so that the acoustic emitter means produces an audible sound signal which varies in a continuous manner with the amplitude of the received reflected ultrasonic pulse when and only when said indicating means is located at a distance from said probe which has a given ratio to a total forward and return transit time of said ultrasonic pulses and reflected ultrasonic pulses, respectively.