JPS6337662B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical sector scanning type ultrasonic diagnostic apparatus, and more particularly, to a probe section comprising a plurality of ultrasonic transducers supported on a common rotation axis at equal rotation angle intervals. The transducer is selectively driven in synchronization with the rotation while being rotated, and the ultrasonic beam is transmitted and received through an ultrasonic transmission window formed in a probe cover that covers the probe section, thereby dividing the transmitted and received ultrasonic beam into sectors. The present invention relates to an ultrasonic diagnostic apparatus of mechanical sector scanning type with a rotating probe section that scans in a circular motion.

Note that "ultrasound" usually refers to sound waves with a frequency exceeding the upper limit of the audible range, that is, a frequency of about 20 KHz or higher, but in this case it is not limited to ultrasonic waves in the narrow sense, but also refers to phenomena, etc. The expression ``ultrasonic waves'' includes sound waves of other frequencies that can be treated almost in the same way as the above-mentioned sound waves.

FIG. 1 shows the configuration of a probe rotating section in an example of this type of ultrasonic diagnostic apparatus. For example, as shown in the figure, four ultrasonic transducers are
T ₁ to _{T 4} are arranged and attached to the probe rotating support part H at angular intervals of θ=90° to form the probe part P, and an ultrasound transmission window W that approximately corresponds to the planned sector scanning angle is formed.
The probe part P and the probe cover C are housed in a probe cover C, and the space between the probe part P and the probe cover C is filled with an ultrasonic transmission medium M such as water or silicone. Then, the probe section P is rotated integrally, and each of the transducers _T1 to _T4 is selectively driven at a predetermined timing to transmit and receive ultrasonic waves. When the probe section P is rotationally driven in the direction of arrow D from the state shown in _FIG.
emits n ultrasonic pulses between angles θ corresponding to the ultrasonic transmission window W, and sequentially transmits them to the transducer.
Each transducer T _{1 to} T ₄ is driven to generate n ultrasonic pulses each time it faces the ultrasonic transmission window while rotating as T _{1 , T 2} , T ₃ , and T ₄ .

In this way, the transducer can be rotated while
Ultrasonic pulses are generated by selectively driving the transducers _T1 to _T4 , and this selectively driving the transducers _T1 to _T4 is performed by driving the probe part P such as an encoder provided in connection with the probe rotation support part H, etc. Since this is performed in synchronization with the rotational position detection output, in order to match the ultrasonic pulse generation position and the ultrasonic transmission window W position, the emission position of the first ultrasonic pulse of a series of ultrasonic pulses from each transducer is determined. It is necessary to match the position A shown in the figure. If this deviates, as shown in FIG. 2, the ultrasound beam group in the portion indicated by the broken line that deviates from the ultrasound transmission window W is cut off by the probe cover C and becomes ineffective. In extreme cases, it may even occur that all of the generated ultrasound pulse beams deviate from the ultrasound transmission window W.

FIG. 3 is a block diagram showing the circuit configuration of a conventional device, and FIGS. 4a to 4g are timing charts thereof.

In FIG. 3, the probe section P is mechanically directly connected to a motor 1 for rotationally driving it and an encoder 2 for detecting the rotational angular position, and is simultaneously rotated by the operation of the motor 1. From the encoder 2, there is a probe part P for detecting the rotation angle position.
One position detection pulse PP per revolution [Figure 4a]
and an ultrasonic emission timing pulse TP (FIG. 4b), and the position detection pulse PP is used as a clear pulse for the counter 3. The counter 3 divides the frequency of the timing pulse TP to form a frame synchronization pulse FS and the like. In addition, display sweep signals are generated by X-axis and Y-axis display sweep signal generation circuits 4 and 5 based on the count value output of the counter 3, etc., and the display sweep signals cause the display 6 to display a raster pattern corresponding to sector scanning. sectors are displayed. Further, gate pulse generation circuits 7 to 10 generate time-based gate signals for driving each transducer T ₁ to _{T 4} of the probe section P using the frame synchronization pulse FS, and these gate pulse generation circuits 7 to 10 Gate circuits (NAND gates in this case) 11 to 1 with the output of
4 selectively open each transducer T ₁ ~
Trigger pulses DP ₁ to 18 are applied to pulsers 15 to 18 for respectively driving T ₄ and generating ultrasonic pulses.
Give DP ₄ [Figure 4 d-g]. Since the probe part P is rotating, the outputs of the pulsers 15 to 18 are transmitted to the signal transmission part 1 consisting of rotating contacts, slip rings, etc.
9 to the transducer T ₁ of the probe section P
Given to T ₄ .

This is an overview of the configuration and operation of the conventional device.
The movers rotate on the same rotation axis, and the probe cover C does not rotate. For example, if the sector scanning angle is 90 degrees, the relative angle of the ultrasonic transmission window W of the probe cover C is normally set to around 110 degrees with some margin. In addition, the timing reference for the circuit system that drives transducers T ₁ to _{T 4} is encoder 2.
It is given by the rotation angle position detection pulse PP obtained from . Here, if the mounting position of the probe cover C, that is, the mounting direction with respect to the encoder 2, is shifted, the direction of the ultrasound beam group will no longer match the ultrasound transmission window, resulting in an ineffective portion as shown by the broken line in Fig. 2. arise. It is difficult to completely prevent this positional shift during installation because the probe cover C and encoder 2 are not mechanically connected. In addition, the presence or absence of this positional shift cannot normally be confirmed unless the ultrasonic beam is actually generated in an almost completely assembled state, and if a positional shift is discovered, the device must be disassembled and reinstalled and reassembled. Otherwise, it is not possible to correct positional deviations, the work is complicated, and accurate alignment is not easy. In the case of the above-mentioned positional deviation, the part that comes into contact with the subject is the ultrasound transmission window W of the probe cover C, so an image is displayed for the part corresponding to the broken line in Figure 2, that is, the invalid part. (raster only).

The present invention was developed against the background of the above circumstances, and it facilitates adjustment of the timing of driving the transducer of the probe section and the relative relationship between the ultrasonic transmission window of the probe cover, and improves the direction of the ultrasonic beam and the ultrasonic wave transmission window. It is an object of the present invention to provide an ultrasonic diagnostic apparatus that can eliminate positional deviation of a transmission window.

In other words, the present invention is characterized by electrically delaying the rotational angle synchronization signal obtained by detecting the rotational angle position of the probe section in order to selectively drive the transducer, and adjusting the delay time within a predetermined range. The purpose of this invention is to provide a variable delay means that makes it possible.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 and FIGS. 6 a to 6 l are a block diagram showing the configuration of one embodiment of the present invention and a timing chart for explaining the operation, respectively. In these FIGS. 5 and 6 a-l, the same parts and signals as in FIGS. 3 and 4 a-g are given the same reference numerals, and detailed explanation thereof will be omitted.

That is, the configuration shown in FIG. 5 has a variable delay circuit 20 inserted between the encoder 2 and counter 3 in FIG. It is assumed that the delay time can be arbitrarily adjusted within the range from zero to a time T corresponding to one period of the rotation angle position detection pulse PP.

In such a configuration, if the delay time Td of the variable delay circuit 20 is adjusted, the delayed rotational angle position detection pulse PPd [Fig. 6h] is given to the counter 3 as a clear signal. The output frame synchronization pulse FS etc. is delayed by the time Td, and therefore the trigger pulses DP ₁ to DP ₄ given to the pulsers 15 to 18 [Fig. 6 i to l]
The outputs of the display sweep signal generation circuits 4 and 5 can be electrically shifted by the delay time Td.

In this way, by adjusting the delay time Td, the ultrasonic beam direction can be electrically moved arbitrarily in the rotational direction, and the direction of the ultrasonic transmission window W when the probe cover C is attached can be changed. Even if the ultrasonic beam direction is in such a direction, the ultrasonic beam direction can be made to coincide with the position of the transmission window W.

In addition, to detect the installation position deviation of the probe cover C, for example, insert the entire probe with the probe cover C attached into a circular acrylic water tank filled with water, operate it, and observe the echo image obtained. Then, in the direction where the ultrasonic beam is being emitted and is not facing the ultrasonic transmission window W, the ultrasonic wave is cut off by the probe cover C, so the echo image of the acrylic aquarium is not displayed and only the raster image is displayed. Is displayed. Since the angle of this portion corresponds to the angle of positional deviation, positional deviation can be eliminated by setting the delay time Td accordingly. Since the adjustment of the delay time Td is an electrical operation, the delay time of the variable delay circuit 20 is adjusted so that all the echo images of the acrylic aquarium are displayed on the display raster while observing the echo image of the acrylic aquarium mentioned above. By adjusting Td, the positional deviation can be detected and adjusted extremely easily and reliably.

As described in detail above, according to the present invention, it is possible to easily adjust the relative relationship between the timing of driving the transducer of the probe section and the ultrasound transmission window of the probe cover, and to adjust the relative relationship between the ultrasound beam direction and the ultrasound transmission window. It is possible to provide an ultrasonic diagnostic apparatus that can eliminate positional deviation.

Note that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing the structure of the probe peripheral portion of the ultrasound diagnostic apparatus according to the present invention, FIG. 2 is a diagram for explaining the positional shift of the ultrasound transmission window of the probe cover, and FIG. 3 4 is a block diagram showing a circuit configuration of an example of a conventional device; FIGS. 4a to 4g are timing charts for explaining the operation of the same example; FIG. 5 is a block diagram showing a circuit configuration of an embodiment of the present invention; FIGS. 6a to 6l are timing charts for explaining the operation of the same embodiment. P...Probe part, H...Probe rotation support part, _T1 to _T4 ...Ultrasonic transducer, C...
...Probe cover, W...Ultrasonic transmission window, 1...
Motor, 2... Encoder, 3... Counter,
4, 5...Display sweep generation circuit, 6...Display device, 7-10...Gate pulse generation circuit, 11-
14...Gate circuit, 15-18...Pulser, 1
9...Signal transmission section, 20...Variable delay circuit.

Claims (1)

[Claims] 1. A probe cover with an ultrasonic transmission window formed thereon;
A probe section that is rotatably provided on the probe cover and that supports a plurality of ultrasonic transducers at equal rotation angle intervals on a common rotation axis, and a motor that rotationally drives this probe section. and an encoder that detects the rotation angle of the probe section, and selectively drives the transducer in synchronization with the rotation while rotating the probe section to transmit an ultrasound beam from the ultrasound transmission window. In a mechanical sector scanning type ultrasonic diagnostic device with a rotating probe unit that scans transmitted and received ultrasound beams in sectors by transmitting and receiving, the rotational angle synchronization signal based on the rotational angle position signal obtained by the encoder can be adjusted within a scheduled range. An ultrasonic diagnostic apparatus characterized in that a variable delay means is provided to delay the transducer and to delay the display sweep signal.