JPH04351956A - Ultrasonic microscope - Google Patents

Abstract

PURPOSE:To provide an ultrasonic microscope capable of deducing a position of an acoustic lens accurately and of forming an accurate image without being influenced by inclination of a mobile body. CONSTITUTION:An ultrasonic microscope moves a mobile body holding an acoustic lens 13 in the prescribed direction while using a position dislocated from the central point as a point of action, and puts ultrasonic waves in respective positions on the surface of a sample S from the acoustic lens 13, and takes in respective reflected waves of the sample, and uses them as picture element data, and forms an image while using a position of the acoustic lens 13 in the case when the ultrasonic waves are put in as a picture element position. There are provided a moving distance detecting means to detect respective moving distances of both edge parts in the lengthwise direction of the mobile body, an inclination operation means to calculate inclination of a line connecting those both edge parts from the moving distances of the both edge parts of the moving body detected by means of this moving distance detecting means and a means to obtain positional dislocation of the acoustic lens 13 from the line inclination obtained by means of this inclination operation means.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic microscope capable of scanning a sample with ultrasonic waves to form an ultrasonic image of the sample.

0002

[Prior Art] Conventionally, a transmitted signal is converted into an ultrasonic wave by a transducer, this ultrasonic wave is made incident on a sample as a focused spherical wave by an acoustic lens, and the reflected wave from the sample is captured and converted into information at a single point. An ultrasound microscope is known that forms an ultrasound image by relatively two-dimensionally scanning a specimen and a specimen.

[0003] Such an ultrasonic microscope can use a lens scanner configured as shown in FIG. 6, for example, in order to relatively two-dimensionally scan an acoustic lens and a sample. This means that the Y stages 1a and 1b are arranged parallel to each other with a distance corresponding to the stroke of the acoustic lens 2, and the X stage 3 holding the acoustic lens 2 is placed on the Y stages 1a and 1b.
The two ends thereof are fitted into Y stages 1a and 1b so as to be slidable in the Y direction. And Y stage 1a,
X stage 3 is attached to feed screws 4a and 4b provided on 1b.
Both ends of the feed screw 4a are screwed together, and both feed screws 4a are screwed together.
, 4b are connected by a timing belt 5. One feed screw 4a has a motor 6 attached to one end and a Y
A Y encoder 7 is attached to detect the position in the direction. Similarly, the X stage 3 also has the X of the acoustic lens 2.
An X encoder (not shown) is provided to detect the directional position.

According to the lens scanner configured in this way, the driving force of the motor 6 is transmitted to both the feed screws 4a, 4b as the same amount of rotation in the same direction, and the X stage 3 is transmitted to both the feed screws 4a, 4b by the same amount of rotation. It moves in the Y direction using the threaded part as the point of action. Furthermore, the acoustic lens 2 can be moved in the X direction by the X stage 3.

During drawing, the X stage 3 is moved to an arbitrary position in the Y direction, and at that position the acoustic lens 2 is moved in the X direction to scan one line in the X direction. When one line scanning is completed, the X stage 3 is moved by one pixel in the Y direction, and one line scanning is performed again in the X direction. In this way, the sample is two-dimensionally scanned, and the reflected ultrasound waves at each point on the sample are stored as pixel data. At the same time, the encoder output of the Y encoder 7 and the X
Store the encoder output of the encoder. Then, using this encoder output as position coordinate data, an image is formed from the above pixel data.

[0006]

[Problems to be Solved by the Invention] By the way, the lens scanner described above has feed screws 4a at both ends of the X stage 3.
, 4b are screwed together, and the point of action when moving the X stage 3 in the Y direction is not located at the center, so when the X stage 3 moves, the longitudinal direction of the X stage 3 is
There is a possibility that it will be tilted by a predetermined angle with respect to the direction. When the X stage 3 is tilted, the position of the acoustic lens 2 will shift depending on the amount of tilt.

However, since the Y encoder 7 for detecting the position of the acoustic lens 2 in the Y direction is provided on one of the feed screws 4a, even if the X stage 2 is tilted, it cannot be detected. Can not. Therefore, there is a possibility that an image may be formed using coordinate data at a position that is different from the actual position, and there is a problem that it becomes impossible to form an accurate image.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to accurately determine the position of the acoustic lens even when the moving body supporting the acoustic lens is tilted. The purpose of the present invention is to provide an ultrasonic microscope that can form accurate images.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention moves a movable body holding an acoustic lens in a predetermined direction using a position shifted from its center point as a point of action, thereby improving the surface of a sample. In an ultrasound microscope that injects ultrasonic waves from the acoustic lens into each position and captures the reflected waves of each sample and uses them as pixel data to form an image using the acoustic lens position at the time of the ultrasonic incident as the pixel position, the movement of the ultrasonic microscope is performed. A movement amount detection means that detects the amount of movement of both ends of the body in the longitudinal direction, and an inclination of a line connecting the two ends is calculated from the amount of movement of both ends of the moving body detected by the movement amount detection means. The present invention is configured to include a tilt calculating means and a deviation amount calculating means for calculating the positional deviation of the acoustic lens caused by the tilt of the moving body based on the line slope data obtained by the tilt calculating means.

0010

[Operation] According to the present invention, which takes the above-mentioned measures, the amount of movement of both longitudinal ends of the movable body holding the acoustic lens is detected by the movement amount detection means, and the detection results are used by the inclination calculation means. The tilt of the moving object is detected from both movement amounts. Here, when the tilt of the moving body is detected, the amount of positional shift of the lens position caused by the tilt of the moving body is calculated by the shift amount calculating means. Therefore, since the amount of deviation of the acoustic lens position can be obtained, the true position of the acoustic lens can be determined, and accurate image formation can be realized.

[0011]

[Embodiment] An embodiment of the present invention will be described below. FIG. 1 shows functional blocks of an ultrasound microscope according to one embodiment.

In this ultrasound microscope, a transmission signal outputted from a transmitter 11 in response to a transmission trigger signal is converted into an ultrasound by a piezoelectric transducer 12, and the ultrasound is focused at one point by an acoustic lens 13 and is incident on a sample S. . The reflected ultrasound from the sample S enters the acoustic lens 13 again, is converted into an electrical reception signal by the piezoelectric transducer 12, and then enters the receiver 14. The receiver 14 extracts only a desired signal from the received signal, A/D converts it, and stores it in the image memory 15 as image data. CPU16
operates based on the flowcharts shown in FIGS. 2(a) to 2(c), and controls the lens scanner 17 to store image data obtained by two-dimensionally scanning the sample S with ultrasonic waves in the image memory 15. Further, the image data stored in the image memory 15 is subjected to line slope calculation processing and slope correction processing, which will be described later, based on the encoder output of the lens scanner 17, thereby correcting the pixel positions of the image data. The image data after the tilt correction process can be displayed on the CRT 18 if necessary. FIG. 3 shows the configuration of the lens scanner 17.

In the lens scanner 17, Y feed screws 22a and 22b made of ball screws are respectively arranged on two opposing sides in the Y direction of the upper end opening of the support frame 21, and a Y feed screw 22a, 22b is provided at one end of one Y feed screw 22a. The motor 23 is attached,
A Y encoder 124a is attached to the other end. Further, the other Y feed screw 22b has a Y encoder 24b attached to the other end.

A timing belt 25 is stretched between the Y feed screws 22a and 22b, so that the motor 23 applies the same amount of rotation to the Y feed screws 22a and 22b at the same timing. In addition, each Y feed screw 22a, 2
2b has a moving member 26 (the Y feed screw 22b side is not shown)
are screwed together.

An X stage 27 whose longitudinal direction is orthogonal to the Y direction is provided at the upper end opening of the support frame 10. This X stage 27 has each Y feed screw 2 at both ends thereof.
A moving member 26 screwed onto 2a and 22b is fixed respectively. Further, guide rails 28a, which are provided parallel to the Y direction along each of the Y feed screws 22a, 22b,
28b in a slidable manner.

The X stage 27 is provided with an X feed screw 29 along the X direction, which is its longitudinal direction. The X feed screw 29 has a motor 31 attached to one end and an X encoder 32 attached to the other end.

[0017] The X stage 27 also has an X
A linear ball guide is provided along the direction, and a lens holding member 33 is slidably attached to this linear ball guide. A moving member of an X feed screw is fixed to the lens holding member 33, and as the X feed screw 29 rotates, the lens holding member 33 itself moves in the X direction. The acoustic lens 13 is attached to this lens holding member 33. In addition, acoustic lens 1
One end of a signal cable is connected to the connector section 34 provided on the side surface of the receiver 3, and is connected to the transmitter 11 and receiver 14, respectively, via this signal cable. The operation of this embodiment configured as above will be explained with reference to FIG. 2.

The X stage 27 is fixed at an arbitrary position in the Y direction, and the X motor 31 is driven to move the acoustic lens 13 in steps to scan the sample S one line in the X direction. The pixel data obtained at each point in the X direction are sequentially stored in the image memory 15.

Next, the inclination α in the longitudinal direction of the X stage 27
is calculated based on the flowchart shown in FIG. 2(b). For example, a description will be given assuming that the X stage 27 is tilted as shown in FIG. Note that the reference numeral A is a threaded portion between one end of the X stage 27 and the Y feed screw 22a, and serves as one point of action of the X stage 27. Further, reference numeral B denotes a threaded portion between the other end of the X stage 27 and the Y feed screw 22b, and serves as the other point of action of the X stage 27.

First, Y encoders 24a and 24b are attached to the other ends of both Y feed screws 22a and 22b, respectively.
Read the positions of each point of action A and B detected in . Next, the position coordinate Y2 of the point of action B is subtracted from the position coordinate Y1 of the point of action A. Then, this subtracted value (Y1-Y2) is divided by the length L of one line, and this divided value (Y1-Y2)/L is set as the slope α. The calculated slope data α is stored for each scanning line. Once the image data and tilt data α have been obtained for all lines, the image data is read out and the tilt correction process shown in FIG. 2(c) is performed.

This is calculated by multiplying the position m of the pixel to be corrected in the X direction by the slope α of the line to which the pixel belongs,
Find the amount of deviation Δy=m×α. Next, the pixel position of the pixel is corrected in the Y direction by the amount of deviation Δy. As a result, the position data of the pixel becomes position data in which the amount of shift caused by the inclination of the X stage 27 is corrected. In addition,
The position m in the X direction is position data detected by the X encoder 32 when the acoustic lens 13 is moved step by step in the X direction. This position data is stored in association with each pixel. Such correction processing is performed for all pixels, the image data in the image memory 15 is rewritten to the data after the correction processing, and the processing is completed.

As described above, according to this embodiment, the X stage 2
A Y encoder 24a, 24b is provided on each of the Y feed screws 22a, 22b that drive the X stage 27, and the amount of movement of both ends of the X stage 27 is detected separately, and the inclination α of the X stage 27 is determined from the detection result. Furthermore, since the pixel position of the image data is corrected by calculating the amount of deviation from the tilt α, even if the X stage 27 is tilted, the error due to the tilt can be removed from the pixel position data, resulting in extremely accurate images. can be formed. Furthermore, since the pixel position and the acoustic lens position match, the accurate acoustic lens position can also be determined from the amount of deviation.

In the above embodiment, a pair of Y encoders provided on the Y feed screw are used to detect the amount of movement of both ends of the X stage 27, but other position detection means may also be used. can. FIG. 4 is a diagram showing a modification of the above embodiment. Note that the same parts as those of the lens scanner 17 shown in FIG. 3 are given the same reference numerals.

In this modification, Y guide rails 41a, 4
1b and linear scales 42a and 42b, respectively, and the X stage 27 is slidably fitted to the Y guide rails 41a and 41b. In addition, in the modified example, a configuration is shown in which the Y feed screw 22a is screwed into only one end of the X stage 27 and driven. In addition, the linear scale 42
The position data of the X stage 27 detected by a and 42b is handled in the same way as the encoder signal in the above embodiment.

According to this modification, the X stage 27
Since the amount of movement of both ends of the X stage 27 can be detected, the error caused by the inclination of the X stage 27 can be removed from the pixel position data as in the previous embodiment, and an image can be formed accurately. Moreover, linear scale 42
Since a and 42b can directly detect the amount of movement of the X stage 27, measurement accuracy can be improved compared to an encoder that detects the position via a ball screw. Furthermore, in this modification, the X stage 27 is driven only by the ball screw 22a on one side, so the configuration of the apparatus can be simplified.

[0026]

Effects of the Invention As detailed above, according to the present invention, even if the moving body supporting the acoustic lens is tilted, the position of the acoustic lens can be accurately determined and an accurate image can be formed. We can provide an ultrasonic microscope that can perform

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of an ultrasound microscope according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the operation of the ultrasound microscope according to one embodiment.

FIG. 3 is a perspective view of a lens scanner portion of an ultrasound microscope according to an embodiment.

FIG. 4 is a perspective view of a lens scanner portion of an ultrasound microscope according to a modification of the embodiment.

FIG. 5 is a schematic diagram showing the tilt state of the X stage.

FIG. 6 is an exploded perspective view of a lens scanner portion of a conventional ultrasound microscope.

[Explanation of symbols]

13...acoustic lens, 15...image memory, 16...CPU,
17...Lens scanner, 24a, 24b...Y encoder.

Claims (1)

[Claims] 1. A movable body holding an acoustic lens is moved in a predetermined direction with a position offset from its center point as a point of action, and ultrasonic waves are applied from the acoustic lens to each position on the sample surface. In an ultrasonic microscope that captures reflected waves from a sample and uses them as pixel data to form an image using the acoustic lens position when ultrasonic waves are incident as the pixel position, movement that detects the amount of movement of both ends of the moving body in the longitudinal direction, respectively. an amount detecting means, an inclination calculating means for calculating the slope of a line connecting both ends of the moving object from the amount of movement of both ends of the moving object detected by the moving amount detecting means; An ultrasonic microscope characterized by comprising: a displacement calculation means for calculating a positional displacement of a lens based on the line inclination data obtained by the inclination calculation means.