JPH0433458B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to ultrasonic waves used in ultrasonic diagnostic equipment that oscillates ultrasonic waves, detects and analyzes the reflected waves, and images the movements and structures of internal organs within the human body. It's about scanners.

Conventional configurations and their problems Ultrasonic scanners include so-called mechanical scanners that scan ultrasonic waves by rotating an ultrasonic transducer that emits ultrasonic waves and senses reflected waves, and electronic scanners that use piezoelectric elements in an array. There is.

FIG. 1a is a plan view of a conventional ultrasonic mechanical scanner, and FIG. 1b is a side view thereof. In the scanner shown in FIG. 1, a drum 2 on which three ultrasonic transducers 1 are attached on the circumference is housed in an ultrasonic cell 4 filled with an ultrasonic propagation substance 3, and the drum 2 is moved by a pulley 5.
motor 7 via rotary encoder 6
The ultrasonic transducer 1 is rotated by the ultrasonic transducer 1 to perform rotational scanning. That is, ultrasonic waves 9 are transmitted from the ultrasonic transducer 1 into the subject 8, the reflected signal from within the subject 8 is received again by the ultrasonic transducer 1, and the signal is processed by the receiver, after which the ultrasonic tomography The image is displayed and the inside of the subject 8 is inspected.

FIG. 2 shows a schematic configuration of the signal processing and image display. Ultrasonic transducer 1 attached to drum 2
rotates at high speed in the direction of arrow A, and transmits and receives ultrasonic waves 9 toward the subject 8 at equal angular intervals from the position A to the position B. Analyzer 1 analyzes the received ultrasonic waves.
3, and the beam is scanned on the cathode ray tube 14 as shown in the figure to form an image inside the subject 8. The output pulses of the rotary encoder 6 are used as a chopper for transmitting and receiving the ultrasonic waves and as a detector for the rotational scanning position.

Such an ultrasonic scanner has the following problems. First, since the components of the ultrasonic cell 4, rotary encoder 6, and motor 7 are relatively large, their characteristics cannot be utilized as a mechanical scanner aiming at miniaturization. Second, since rotational scanning position detection is performed by the rotary encoder 6 via the pulley 5, the rotational angle error during transmission directly becomes a rotational scanning position detection error, resulting in image distortion.

Purpose of the Invention The present invention solves the conventional problems as described above, enables inspection of a subject from all angles, prevents rotation angle errors, and improves image precision.
The object of the present invention is to provide an ultrasonic scanner that is miniaturized.

Configuration of the Invention The ultrasonic scanner of the present invention has a configuration in which an ultrasonic transducer for transmitting and receiving ultrasonic waves is rotated at high speed via a pulley, and a magnetization pattern provided over the entire circumference of the side surface of the pulley is The rotation angle of the ultrasonic transducer is detected by counting with a magnetoresistive element provided on the housing side facing the pulley.

DESCRIPTION OF EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 3a is a plan view of an ultrasonic scanner according to an embodiment of the present invention, and FIG. 3b is a right side view thereof. In the ultrasonic scanner shown in FIG. 3, a drum 16 on which three ultrasonic transducers 15 are attached on the circumference is housed in an ultrasonic cell 18 filled with an ultrasonic propagating substance 17, and the drum 16 is connected to a pulley 19. It is rotated by an intervening motor 20 to perform rotational scanning of the ultrasonic transducer 15. Ultrasonic waves 22 are transmitted from the ultrasonic transducer 15 into the subject 21, the reflected signal from within the subject 21 is received again by the ultrasonic transducer 15, and the signal is processed by the receiver, after which an ultrasound tomographic image is generated. indicate. Detection of the rotational scanning position in signal processing and imaging of the received reflected ultrasound waves is performed using a magnetic storage medium 2 on the side of the pulley 19 that transmits the rotation of the drum 16.
3 is formed, and a magnetization pattern obtained by dividing the circumference at equal intervals is written on the magnetic storage medium 23 to form a magnetic scale 24, which is detected by a magnetoresistive element head 25 opposed to the magnetic scale 24 without contact. Do by doing. The magnetization pattern is written with the pulley 19 attached to the shaft of the drum 16. The required rotational scanning position signal is a two-phase signal with a 90° phase shift and an origin signal with a pulse division number of 200 per rotation. In order to form the magnetic scale 24 that satisfies these requirements, the pulley 19 must be sized to have a diameter of 10 mm.
A millimeter is sufficient.

FIG. 4a is an enlarged view of the pulley 19 and the magnetoresistive element head 25, and FIG. 4b is an enlarged view of the pulley 19.
The relative relationship between the magnetic scale 24 provided above and the magnetoresistive elements A, B, and Z is shown in FIG. 4c, and the output waveforms of the magnetoresistive elements A, B, and Z are shown in FIG. A magnetic storage medium 23 is formed on the pulley 19, and a magnetization pattern is written and recorded to form a magnetic scale 24. The magnetoresistive element head 25 forms the magnetoresistive medium into a rectangular shape, with A and B located at positions A and B shifted by 1/4 of the magnetization pattern pitch P on the outer track, and an origin on the inner track. The resistance values of the magnetoresistive elements A, B, and Z change at equal intervals as shown in FIG. 4c as the magnetization pattern rotates. By detecting this change in resistance value with a bridge circuit, converting the output signal into pulses and counting them based on the Z signal, the absolute rotational position can be determined, and at the same time, it becomes a signal source for equally spaced choppers.

The ultrasonic scanner of this embodiment provides the following effects. First, since the drive pulley itself functions as a rotary encoder, almost no space is required to mount the rotary encoder, and the size can be reduced to about half of the conventional size. This makes it possible to diagnose the inside of the subject from all angles and greatly improves operability. Second, since the rotation scanning position can be detected directly without using a pulley, very accurate detection is possible, and a highly accurate image can be obtained.

Effects of the Invention As is clear from the above embodiments, the present invention provides a magnetic circuit scale consisting of magnetization patterns recorded at regular intervals around the entire side surface of a pulley that rotates coaxially with a drum provided with an ultrasonic vibrator. , is equipped with a magnetoresistive effect element provided opposite to the magnetic circuit scale, and detects the rotational position of the drum by counting the magnetization pattern, so there is little influence from noise, etc., and it is less susceptible to temperature changes and changes over time. In addition, since there is no need for circuit adjustments for position detection, the rotational scanning position can be detected accurately without errors, high-precision images can be obtained, and the object can be inspected from all angles. This has the effect that the device can be made smaller.

[Brief explanation of drawings]

Figures 1a and b are a plan view and a right side view illustrating the configuration of a conventional ultrasonic scanner, and Figure 2 is a schematic configuration diagram of the signal processing/image display system of the ultrasonic scanner.
Figures 3a and 3b are a plan view and a right side view of an ultrasonic scanner according to an embodiment of the present invention, Figure 4a is an enlarged view of the pulley and the magnetoresistive element head, and Figure 4b is a magnetic scale and FIG. 4c, which is a diagram for explaining the relative positional relationship of the magnetoresistive elements, is a diagram showing the output waveform of the magnetoresistive element. 15... Ultrasonic vibrator, 16... Drum, 17
... Ultrasonic propagation material, 18 ... Ultrasonic cell, 19
... Pulley, 20 ... Motor, 21 ... Subject, 22 ... Ultrasonic wave, 23 ... Magnetic storage medium, 2
4... Magnetic scale, 25... Magnetoresistive element head.

Claims (1)

[Claims] 1 A drum equipped with an ultrasonic vibrator that transmits and receives ultrasonic waves, a magnetic circuit scale consisting of a magnetization pattern recorded at regular intervals over the entire circumference of the side surface, and a pulley coaxially fixed to the drum. and a magnetoresistive element provided on a housing facing the magnetic circuit scale, and detects the rotational position of the drum by counting the magnetization pattern.