JP3727835B2 - Ultrasonic probe - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to an ultrasound probe and an ultrasound diagnostic apparatus that obtain an ultrasound tomographic image by scanning an ultrasound beam from an ultrasound transducer.
[0002]
[Prior art]
The ultrasonic probe scans an ultrasonic transducer electrically or mechanically to obtain an ultrasonic tomographic image.
[0003]
Hereinafter, a conventional configuration of the mechanical scanning ultrasonic probe will be described with reference to FIG.
[0004]
In FIG. 5, the ultrasonic probe is rotatable by being filled with an ultrasonic propagation medium such as butanediol in the housing 2 and the motor 3 with an encoder fixed to the frame 4 and the housing 2 in the housing 2. The ultrasonic transducer 5 for transmitting / receiving ultrasonic waves, the drive side gear 6 for transmitting the driving force of the motor 3 with encoder and rotating the ultrasonic transducer 5 and the follower, which are attached to the frame 4 so as to become It comprises a side gear 7, an oil seal 8, an encoder control circuit 9 for controlling the motor 3 with encoder, and a coaxial cable 10 for transmitting and receiving various signals from the ultrasonic diagnostic apparatus main body to the encoder control circuit 9. Further, as described in Japanese Patent Application Laid-Open No. 05-91594, a conventional ultrasonic diagnostic apparatus generally includes an internal circuit and a cable from external electromagnetic field noise in the ultrasonic probe housing 1. A shield plate 13 connected to the shield of the coaxial cable 10 is provided to block off or suppress unnecessary radiation from the internal circuit and cable.
[0005]
[Problems to be solved by the invention]
Recent circumstances surrounding the ultrasonic diagnostic apparatus include an increase in electromagnetic interference due to an improvement in reception sensitivity, and strengthening of EMC comprehensive regulations in Europe.
[0006]
Since the ultrasonic probe is connected to the ultrasonic diagnostic apparatus main body via a coaxial cable of about 2 m, the shield in the probe case is in a state of being floated with respect to the ground.
[0007]
In the above-described conventional configuration, when a charged human body touches the ultrasonic probe, electrostatic discharge occurs inside the probe due to insulation breakdown at the boundary between the probe housing and the housing. May occur. In this case, direct charge injection into the internal circuit can be avoided by the shield plate 13 connected to the shield of the coaxial cable. However, when a discharge current flows through the shield plate that is floating in potential with respect to the ground, the current path acts as a radiating antenna, and the radiated electromagnetic noise is picked up by the control circuit inside the probe, causing malfunction. Tie.
[0008]
The present invention solves the above-described problems, and an object thereof is to provide an ultrasonic probe that can prevent malfunction of an internal control circuit.
[0009]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a rotation driving means, an ultrasonic transducer that is rotatably supported by a frame, and transmits and receives ultrasonic waves, and a rotation driving means. An ultrasonic probe comprising: a motor for driving the encoder; an encoder control circuit for controlling the motor; and a shield plate having a concave and / or convex structure connected to a shield of a coaxial cable including the encoder control circuit A child.
[0010]
Furthermore, the present invention provides a rotation driving means in an ultrasonic probe housing, an ultrasonic transducer that is rotatably supported by a frame, transmits and receives ultrasonic waves, a motor for driving the rotation driving means, and a motor. An ultrasonic probe including an encoder control circuit for controlling, and a shield plate having a plurality of holes connected to a shield of a coaxial cable including the encoder control circuit.
[0011]
With these configurations, the present invention can suppress radiated electromagnetic noise generated when a discharge current due to external electrostatic noise flows through the shield plate inside the probe, and prevent malfunction of the internal control circuit.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
Fig.1 (a) is sectional drawing which shows the ultrasonic probe in the 1st Embodiment of this invention. In FIG. 1A, an ultrasonic probe is an ultrasonic probe housing 1, a motor 3 with an encoder fixed to a frame 4, and a housing 2 filled with an ultrasonic propagation medium such as butanediol. And an ultrasonic transducer 5 for transmitting and receiving ultrasonic waves attached to the frame 4 so as to be rotatable, a drive side gear 6 for transmitting the driving force of the motor 3 and rotating the ultrasonic transducer 5, and It comprises a driven gear 7, an oil seal 8, an encoder control circuit 9 for controlling the motor 3, and a coaxial cable 10 for transmitting and receiving various signals from the ultrasonic diagnostic apparatus body to the encoder control circuit 9. Further, a shield plate 11 having a convex structure is provided on the inner surface side connected to the shield of the coaxial cable 10 in order to cut off the internal circuit and cable from external electromagnetic field noise, or to suppress unnecessary radiation from the internal circuit and cable. ing.
[0014]
The shield plate is not limited to a metal plate, but may be a conductive plastic or a thin plate having a conductive film.
[0015]
FIG. 1B is a perspective view of a shield plate having a convex structure on the inner surface side of the present invention. The shield plate of the present invention is obtained by applying a conductive paint having a square shape with a side of about 1 cm and a height of about several millimeters at an interval of about 1 cm.
[0016]
Next, the operation of the first embodiment of the present invention will be described.
[0017]
The surface of the ultrasonic transducer 5 of the housing 2 is applied to the subject, and the motor 3 is driven by supplying a control signal from the ultrasonic diagnostic apparatus main body to the encoder control circuit 9, whereby the drive side gear 6 and the driven side are driven. The ultrasonic probe is rotated through the rotation driving means by the gear 7. Further, the ultrasonic vibration 5 is excited by the high voltage pulse signal from the ultrasonic diagnostic apparatus main body, the ultrasonic wave is radiated to the subject, and the ultrasonic echo signal from the subject is received. A tomogram can be displayed on the screen.
[0018]
Note that the motor 3 may be an integral unit with an encoder or a separate unit.
[0019]
A waveform simulating typical electrostatic noise generated when a human body charged with electric charges touches an ultrasonic probe is shown in FIG. 3 (in accordance with the electrostatic discharge test standard IEC61000-4-2). The radiated electromagnetic wave noise generated when the discharge current due to the electrostatic noise flows through the shield plate includes a high frequency component as shown in FIG. 4, and when the line length through which the discharge current flows is 1/4 wavelength and 1/16 wavelength from the antenna efficiency. Strong emission will cause circuit malfunction.
[0020]
As a rule of thumb, it is considered that a countermeasure can be realized if the line length through which the discharge current flows can be divided by a length of 1/50 wavelength or less. The highest frequency of the harmonic component in FIG. 4 is 615 MHz. By providing the convex structure on the shield plate at an interval of about 1 cm, which is 1/50 wavelength of this frequency, the line length through which the discharge current flows can be cut short, and the antenna efficiency of electromagnetic radiation can be reduced. As a result, noise can be suppressed and malfunction of the internal control circuit can be prevented.
[0021]
A similar effect can be expected by providing a recess (concave structure) on the inner surface of the shield plate instead of the convex structure on the inner surface side. Furthermore, the shield plate of the present invention may be a combination of a convex structure and a concave structure. Further, the shape of the convex structure or the concave structure may be a polygon or a circle other than the quadrangular shape, and the interval may be 1 cm or less. Further, it goes without saying that the shield plate may be a cylindrical shape or the like instead of the prismatic shape, and the holes do not need to be arranged in an orderly manner.
[0022]
FIG. 2A is a cross-sectional view showing an ultrasonic probe according to the second embodiment of the present invention. In FIG. 2A, the ultrasonic probe is rotated by being filled with an ultrasonic propagation medium such as butanediol in the housing 2 and the motor 3 fixed to the ultrasonic probe housing 1, the frame 4, and the housing 2. An ultrasonic vibrator 5 for transmitting and receiving ultrasonic waves attached to the frame 4 so as to become a drive side gear 6 and a driven side gear for transmitting the driving force of the motor 3 and rotating the ultrasonic vibrator 5. 7, an oil seal 8, an encoder control circuit 9 for controlling the motor 3, and a coaxial cable 10 for transmitting and receiving various signals from the ultrasonic diagnostic apparatus main body to the encoder control circuit 9. Furthermore, the present invention provides a shield plate 12 having a hole connected to the shield of the coaxial cable 10 in order to shield the internal circuit and cable from external electromagnetic field noise, or to suppress unnecessary radiation from the internal circuit and cable. It has.
[0023]
FIG. 2B is a perspective view of the shield plate 12 having a hole of the present invention. In the shield plate of the present invention, square holes each having a side of about 1 cm are arranged at intervals of about 1 cm.
[0024]
Also in the second embodiment, similarly to the first embodiment, the line length through which the discharge current of electrostatic noise flows is determined by the wavelength of the harmonic component by the hole-processed structure (hole) provided in the shield plate. It can be broken much shorter and the antenna efficiency of electromagnetic radiation can be reduced. As a result, noise can be suppressed and malfunction of the internal control circuit can be prevented.
[0025]
It goes without saying that the shield plate may be a cylindrical shape instead of the prismatic shape, and the shape of the hole may be other shapes such as a polygon or a circle other than the quadrangular shape, and the interval. May be 1 cm or less. Furthermore, the holes need not be orderly aligned.
[0026]
【The invention's effect】
As described above, the present invention provides a rotation driving means, an ultrasonic transducer that is rotatably supported by a frame and transmits / receives ultrasonic waves, and a rotation driving means for driving the rotation driving means. By providing a motor, an encoder control circuit for controlling the motor, and a shield plate having a concave and / or convex structure connected to a shield of a coaxial cable including the encoder control circuit, a shield inside the probe It is possible to provide an ultrasonic probe that suppresses radiated electromagnetic noise generated when a discharge current due to external electrostatic noise flows through the plate and prevents malfunction of the internal control circuit.
[Brief description of the drawings]
FIG. 1A is a structural diagram of an ultrasonic probe according to a first embodiment of the present invention. FIG. 1B is a schematic diagram showing a convex shield plate according to the first embodiment of the present invention. FIG. 2A is a structural diagram of an ultrasonic probe according to a second embodiment of the present invention. FIG. 2B is a schematic diagram showing a shield plate having a hole drilling structure according to the second embodiment of the present invention. FIG. 3 is an explanatory diagram showing a typical electrostatic noise waveform. FIG. 4 is an explanatory diagram showing a frequency analysis result of electrostatic noise. FIG. 5 is a structural diagram of a conventional ultrasonic probe.
DESCRIPTION OF SYMBOLS 1 Ultrasonic probe housing 2 Housing 3 Motor 4 Frame 5 Ultrasonic vibrator 6 Drive side gear 7 Drive side gear 8 Oil seal 9 Encoder control circuit 10 Coaxial cable 11 Shield plate 12 Shield plate 13 Shield plate

Claims (2)

In the ultrasonic probe housing, a rotation driving means, an ultrasonic transducer that is rotatably supported by a frame and transmits / receives ultrasonic waves, a motor for driving the rotation driving means, and for controlling the motor An ultrasonic probe comprising an encoder control circuit, a shield plate, and a coaxial cable, wherein the shield plate is a harmonic of a discharge current due to static electricity for dividing a path length through which the discharge current due to static electricity flows. An ultrasonic probe having a concave and / or convex structure arranged at an interval of 1/50 wavelength of a wave component and having a shield of the coaxial cable connected to the shield plate . In the ultrasonic probe housing, a rotation driving means, an ultrasonic transducer that is rotatably supported by a frame and transmits / receives ultrasonic waves, a motor for driving the rotation driving means, and for controlling the motor An ultrasonic probe comprising an encoder control circuit, a shield plate, and a coaxial cable, wherein the shield plate is a harmonic of a discharge current due to static electricity for dividing a path length through which the discharge current due to static electricity flows. An ultrasonic probe having holes disposed at intervals of 1/50 wavelength of a wave component, and wherein the shield of the coaxial cable is connected to the shield plate.

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