JP7454740B1 - Waveform simulator and ultrasound imaging device - Google Patents

Abstract

[Problem] To easily set a time gate for an object to be inspected that has a multi-layer structure with multiple inspection interfaces, when ultrasonic waves are irradiated to a laminate, the reflection from the desired interface is detected. To provide a waveform simulator that can obtain reflected waves. A waveform simulator 10 performs a first process of calculating a delay time from when a probe irradiates an ultrasonic wave to a laminate until the probe receives a reflected wave from a target interface, based on layer structure information. a first processing unit 1 that performs a second process of calculating the first transmittance from when the ultrasonic wave is output from the probe until it reaches the target interface; A third processing unit 3 performs a third process of calculating the reflectance of the reflection that occurs inside the target laminated portion, and a second processing unit 3 calculates the second transmittance of the reflected wave from the target interface to the probe. and a fourth processing section 4 that performs the fourth processing. [Selection diagram] Figure 1

Description

The present invention is a waveform simulator that simulates a reflected wave that is reflected back at a target interface that indicates the bottom surface of a target stacked section that indicates a desired stacked section when ultrasonic waves are irradiated to a stacked body having a plurality of layered structures. and an ultrasound imaging device.

Generally, in order to detect defects existing in an inspected object having a plurality of layered structures using ultrasonic waves, reflection characteristics due to differences in acoustic impedance are utilized. Ultrasound propagates through liquids and solid materials, and reflected waves (echoes) occur at the interfaces and gaps between materials with different acoustic impedances. Here, since the reflected waves from defects such as peeling and voids have higher intensity than the reflected waves from areas without defects, it is possible to visualize the reflected intensity at the bonding surface of each layer of the object to be inspected. , it is possible to obtain an image in which defects existing within the inspected body are highlighted.

Ultrasonic imaging equipment scans an ultrasound probe two-dimensionally in the horizontal direction, and uses amplitude information and time information within a time gate (time range of interest) of reflected waves from the inspection target area within the inspection target. Generate a video of the defect. If there is a defect in the inspection target and there is a reflected wave derived from the defect within the time gate, there will be a difference between the reflected wave of the defective inspection target and the reflected wave of a healthy inspection target without defects. It can be observed as a defect image.

The ultrasonic imaging apparatus of Patent Document 1 includes a time gate setting section, and the time gate setting section is configured to calculate a calculation model with no defect in which the defect to be inspected is not set, and with a defect in which the defect is set as a calculation model. A calculation model is input, and the ultrasonic waves propagating through the inspection target are calculated by numerical simulation for each of the calculation model without defects and the calculation model with defects. It is disclosed that the waveform of the ultrasound waveform and the waveform of the ultrasonic wave obtained by the defective calculation model are at least part of different time ranges from each other.

Japanese Patent Application Publication No. 2018-189550

In the device described in Patent Document 1, the propagation of ultrasonic waves can be determined by numerical simulation using an existing simulator, but in order to set the time gate, two types are required: a model without defects and a model with defects. In order to set the time gate without knowing where the defect was, it was necessary to repeat a process of thought and error.

In addition, although existing simulators can obtain the entire waveform of reflected waves, it is difficult to clearly grasp the relationship between structural information and the temporal position of the reflected waves, and it is easy to Unable to set time gate position.

Therefore, an object of the present invention is to enable easy setting of a time gate for an object to be inspected having a multilayer structure with a plurality of inspection interfaces, so that when ultrasonic waves are irradiated to a laminate, An object of the present invention is to provide a waveform simulator and an ultrasonic imaging device that can determine reflected waves reflected from a desired interface.

In order to solve the above problems, the waveform simulator of the present invention has a waveform simulator that, when an ultrasonic wave is irradiated to a laminate having a plurality of layer structures, is reflected at the target interface representing the bottom surface of the target laminated part representing the desired laminated part. A waveform simulator that simulates reflected waves that are returned from A first process of calculating a delay time from when a probe irradiates the ultrasonic wave to the laminated body until the probe receives the reflected wave from the target interface using the thickness and sound velocity of each laminated part. a first processing unit that calculates a first transmittance from when the ultrasonic wave is output from the probe until it reaches the target interface using the sound velocity and density of each of the laminated parts; a second processing unit that performs processing; and a third processing unit that performs a third process that calculates a reflectance of reflection of the ultrasonic wave generated inside the target laminated portion using the sound velocity and density of each of the laminated portions. and a fourth process of calculating a second transmittance of the reflected wave until it reaches the probe from the target interface using the sound speed and density of each of the laminated parts. It is characterized by comprising: and. Other aspects of the present invention will be explained in the embodiments described below.

According to the present invention, when a laminate is irradiated with ultrasonic waves, it is possible to easily set a time gate for an object to be inspected that has a multilayer structure with a plurality of inspection interfaces. The reflected waves reflected from the interface can be determined.

1 is a block diagram showing the configuration of a waveform simulator according to a first embodiment. FIG. FIG. 3 is a diagram showing an example of layer structure information. It is a figure showing a material database. FIG. 3 is a diagram showing an example of calculating delay time. FIG. 3 is a diagram showing an example of calculating a first transmittance. FIG. 3 is a diagram showing an example of calculating reflectance. FIG. 6 is a diagram showing an example of calculating a second transmittance. 7 is a flowchart showing processing of the waveform simulator according to the first embodiment. FIG. 2 is a diagram showing the configuration of an ultrasound imaging device according to a second embodiment. 7 is a flowchart showing processing of an ultrasound imaging apparatus according to a second embodiment. It is a figure which shows the example of the simulated reflected wave displayed on the display part. FIG. 3 is a diagram showing superimposed simulated reflected waves. FIG. 3 is a diagram showing an example of a propagation path in which reflection occurs only in a specific layer. FIG. 7 is a diagram showing waveform data calculated on a propagation path in which reflection occurs only in a specific layer. It is a figure which shows the example of a screen of a waveform simulator. FIG. 2 is a diagram showing a hardware configuration of a waveform simulator and the like.

Ultrasonic imaging equipment irradiates ultrasonic waves onto a semiconductor wafer or semiconductor package that has a multi-layer structure, which is the object to be inspected, and captures the reflected waves that the ultrasonic waves return from the laminate. It is a useful tool for checking the waveform of reflected waves from the target interface, which is the bottom of the target laminated part indicating the laminated part, and inspecting whether there are defects such as peeling or voids in the target interface.

When the laminate of the object to be inspected consists of many layers, the reflected waves are returned from each of the laminate parts that make up the laminate, so the waveform has a continuous waveform with multiple peaks. There is. Therefore, when looking at a waveform to be inspected, a gate is set to extract that waveform. For example, if the object to be inspected is a laminate with a five-layer structure, and the target laminated part is the third layer, and when looking at the reflected waves whose bottom surface is the target interface, surround the reflected waves from the target interface of the third layer. The gate will be set at a position that includes the peak part.

This gate setting work requires skill, and by making the work easier, work efficiency can be greatly improved.

When a laminate is irradiated with ultrasonic waves, the waveform simulator generates a simulated reflected wave that simulates the reflected wave from the target interface, and supports the task of setting an appropriate gate for the reflected wave from the target interface. However, it is possible to perform the work quickly without being affected by the skill level of the operator, and greatly improves the efficiency of inspecting the presence or absence of defects in the laminate.

<First embodiment>
FIG. 1 is a block diagram showing the configuration of a waveform simulator 10 according to the first embodiment.
The waveform simulator 10 includes an input section 9 that inputs layer structure information of the laminate, a material database 7 that stores information regarding materials, and a first processing section 1 (that performs a first process of calculating delay time). (see FIG. 4), a second processing section 2 (see FIG. 5) that performs the second process of calculating the first transmittance, and a third processing section 3 that performs the third process of calculating the reflectance. (see FIG. 6), a fourth processing section 4 (see FIG. 7) that performs a fourth process of calculating the second transmittance, a simulated signal generation section 5 that generates a simulated signal, and a simulated reflected wave. It is configured to include a waveform converter 6 that generates a waveform, and a waveform database 8 (storage unit) that stores delay times and simulated reflected waves.

The input layer structure information 22 includes the material name (material) of each laminated portion constituting the laminated body for which waveform simulation is performed, and the thickness of each laminated portion.

FIG. 2 is a diagram showing an example of the layer structure information 22. In the case of the laminated structure 21 in FIG. 2, the number of laminated layers is five (first layer L1, second layer L2, third layer L3, fourth layer L4, fifth layer L5), and the contains a liquid medium (usually water) that propagates the generated ultrasound waves through the laminate.

The layer structure information 22 includes layer names, material names, and thicknesses. In this figure, the material names of the respective laminated parts are expressed as material 1 and material 2, but in reality, epoxy resin, silicone, etc. are input. Note that the unit of thickness is mm.

FIG. 3 is a diagram showing the material database 7. As shown in FIG. The material database 7 stores sound speeds and densities regarding names of materials constituting the laminate. The waveform simulator 10 uses the sound speed and density of each laminated portion forming the laminated body in the process of generating a simulated reflected wave from the target interface. Therefore, the sound speed and density of various material names are stored in advance in the material database 7, and the sound speed and density of each laminated part are extracted from the material database using the material name of the layer structure information input from the input section 9 as a key. . Note that the unit of sound velocity is m/second, and the unit of density is g/cm ³ . Further, the material database 7 may include acoustic impedance, which will be described later.

FIG. 4 is a diagram showing an example of calculating delay time. FIG. 4 is a diagram regarding the first process of calculating the delay time in the first processing unit 1. When the laminate is irradiated with ultrasound, the ultrasound propagates through each laminate and reaches the substrate. During this propagation process, a propagation delay occurs. The delay time of each laminated portion can be calculated using the following formula.
(Delay time) = (thickness of laminated part) / (velocity of sound in laminated part)
Since the propagation delay occurs in all the laminated parts, the delay time that occurs up to the interface of the nth laminated part can be calculated by the following formula.

Here, n is the number of laminated layers up to the target interface, k is an integer variable from 0 to n, V is the speed of sound, and D is the thickness.

Propagation delay is the delay that occurs before the ultrasonic wave emitted from the probe reaches the target interface, and the delay that occurs before the reflected wave reflected from the target interface returns and reaches the probe, so the final delay is The time can be calculated using the following formula.

FIG. 5 is a diagram showing an example of calculating the first transmittance. FIG. 5 is a diagram regarding the second process of calculating the first transmittance in the second processing unit 2. The ultrasonic waves are attenuated after being emitted from the ultrasonic probe 50 until they reach the target interface while passing through interfaces in front of the target interface. Therefore, for an ultrasonic wave that has not passed through a certain interface, the transmitted wave that has passed through that interface has an amplitude multiplied by the transmittance of that interface. As shown in FIG. 5, for example, the transmittance regarding the interface 1 between the first layer laminated portion and the second layer laminated portion can be calculated using the following formula.

(Transmittance) = (2Z2)/(Z1+Z2)
Here, Z indicates the acoustic impedance of each laminated part,
It can be calculated by Z=(sound velocity of laminated portion)×(density of laminated portion).
Here, Z1 is the acoustic impedance of the laminated portion of the first layer L1, and Z2 is the acoustic impedance of the laminated portion of the second layer L2. Note that Z1 may be expressed as Z ₁ and Zn may be expressed as Z _n .

Attenuation of the ultrasound occurs at each interface through which the ultrasound passes, including the surface of the first layer L1, from when the ultrasound is emitted from the ultrasound probe 50 until it reaches the target interface. Let Y be the amplitude of the ultrasonic wave emitted from 50, let Tk be the transmittance of each interface, let Yk be the ultrasonic wave that is attenuated after passing through each interface, and let the number of layers in the laminate be 3, then the amplitude of the transmitted wave is decreases as follows.

Y0=Y×T0
Y1=Y0×T1
Y2=Y1×T2
Y3=Y2×T3
Here, T0 is the transmittance of the surface of the first layer L1, and Y0 is the amplitude of the transmitted wave transmitted through the surface of the first layer L1.

Therefore, the final transmitted wave Y3 can be calculated as follows.
Y3=Y×T0×T1×T2×T3

Therefore, when the number of laminated layers in the laminate is three, if the overall transmittance of the ultrasonic waves emitted from the ultrasound probe 50 until it reaches the target interface (interface 3) is the first transmittance, then the surface, The first transmittance can be calculated via the interface 1 and the interface 2 using the following formula.
(First transmittance) = T0 x T1 x T2

When the number of layers in the laminate is n, the first transmittance can be calculated using the following formula.
(First transmittance)=T0×T1×...×(Tn-1) (Formula 3)

Therefore, the first transmittance of a laminate having n layers can be calculated using the following formula.
(First transmittance)=(2×Z1/(Z0+Z1))
×...×(2×Zn/((Zn-1)+Zn) (Formula 4)

FIG. 6 is a diagram showing an example of calculating reflectance. FIG. 6 is a diagram regarding the third process of calculating the reflectance in the third processing unit 3. When the ultrasonic waves reach the target laminated portion, reflection occurs between the target interface, which is the bottom surface of the target laminated portion, and the target upper surface, which is the top surface of the target laminated portion. In this embodiment, the reflection will be simply referred to as reflection, and the reflectance will be simply referred to as reflectance. The reflection will occur multiple times, but here it is assumed that it occurs five times. Note that the number of reflections may be changed as necessary.

As shown in Figure 6, there are three reflections from the target interface to the target top surface, and two reflections from the target top surface to the target interface, for a total of five reflections. In other words, the number of reflections from the target interface to the target top surface is one more than the number of reflections from the target top surface to the target interface.

When the acoustic impedance of the target laminated part is Z2, the acoustic impedance of the previous laminated part is Z1, and the acoustic impedance of the next laminated part is Z3, the ultrasonic wave is reflected from the target interface to the upper surface of the target. The first reflectance indicating the reflectance of the first reflection can be calculated by the following formula.
(First reflectance) = (Z3-Z2)/(Z3+Z2)

Further, the second reflectance, which indicates the reflectance of the second reflection of the ultrasonic wave from the upper surface of the object to the object interface, can be calculated by the following equation.
(Second reflectance) = (Z1-Z2)/(Z1+Z2)

As described above, the first reflection within the target laminated portion occurs three times and the second reflection occurs twice, so the overall reflectance can be calculated as follows.
(Reflectance) = (First reflectance) ³ × (Second reflectance) ²
=((Z3-Z2)/(Z3+Z2)) ³ ×((Z1-Z2)/(Z1+Z2)) ²

Therefore, when the n-th laminated part is the target laminated part, it can be calculated using the following formula.
(Reflectance)=((Zn+1)-Zn))/((Zn+1)+Zn)) ³
×((Zn-1)-Zn))/((Zn-1)+Zn)) ² (Formula 5)

FIG. 7 is a diagram showing an example of calculating the second transmittance. FIG. 7 is a diagram regarding the fourth process of calculating the second transmittance in the fourth processing unit 4. In the propagation path from when the ultrasonic wave reaches the target interface to when the reflected wave returns to the probe and is input to the probe, the ultrasonic wave travels along the propagation path from the target interface to the target interface. It is attenuated at each interface through which it passes before reaching the probe. Therefore, in the same way as the first transmittance, by calculating the second transmittance indicating the transmittance from the target interface to the probe and multiplying it by the reflected wave reflected at the target interface, the reflected wave reaching the probe can be calculated. The amplitude of can be calculated.

When the number of layers in the laminate is n and the acoustic impedance of each layer is Zk (k is a positive integer from 0 to n), the second transmittance can be calculated by the following formula.
(Second transmittance)=(2×Z0/(Z0+Z1))
×・・・×(2×(Zn-1)/((Zn-1)+Zn) (Formula 6)

The above describes the processing from the first processing unit 1 to the fourth processing unit 4. As a result of these processes, the process in which the ultrasonic waves emitted from the ultrasonic probe 50 are reflected at the target interface, return to the ultrasonic probe 50, and are input thereto is processed in the waveform simulator as follows.

FIG. 8 is a flowchart showing the processing (S100) of the waveform simulator 10 according to the first embodiment. Refer to FIG. 1 as appropriate. The waveform simulator 10 first inputs laminated structure information of a laminated body to be subjected to waveform simulation from the input unit 9 (S101). Specifically, information regarding the material and thickness of each of the laminated parts from the first layer to the nth layer is input.

Next, the first processing to the fourth processing are executed in the first processing section 1 to the fourth processing section 4 for each of the laminated parts constituting the laminate, and the delay of each laminated part is The time and simulated reflected waves are calculated and stored in the waveform database 8.

The process will be explained in detail.
The waveform simulator 10 inputs layer structure information (S101), sets a parameter n (number of laminated layers), and assigns 1 as its initial value (S102). The waveform simulator 10 sets the laminated part corresponding to the parameter n as the target laminated part, uses the material of the target laminated part included in the input layer structure information as a search key, and extracts the sound velocity and density of the material from the material database (S103 ). The waveform simulator 10 executes the first to fourth processes in the first to fourth processing units 1 to 4 using the sound velocity, density, and thickness of these target laminated parts (S104). ~S107), the delay time, first transmittance, reflectance, and second transmittance are calculated for the target laminated portion.

Next, the waveform simulator 10 generates a simulated signal using the simulated signal generation unit 5 (S108). The simulated signal corresponds to the ultrasound emitted from the probe in an actual ultrasound imaging device. As the simulated signal, it is preferable to use a sinc function as a waveform having a waveform close to that of the actual ultrasonic wave. Note that the sinc function is an elementary function obtained by dividing the sine function by its variable.

The waveform simulator 10 inputs the first transmittance, reflectance, second transmittance, and simulated signal calculated by the above processing to the waveform converter 6, and converts the first transmittance, reflectance, and second transmittance. The amplitude change rate is calculated by multiplying the simulated signal by the amplitude change rate (S109), and the simulated reflected wave is calculated by multiplying the simulated signal by the amplitude change rate (S110). The waveform simulator 10 stores the delay time and the simulated reflected wave in the waveform database in association with the value of n of the target laminated portion (S111).
(Simulated reflected wave) = Y x (first transmittance) x (reflectance) x (second transmittance)
Here, Y is a simulated signal generated by the simulated signal generation section.

While incrementing n, the waveform simulator 10 executes all processes from the first process on all the laminated parts included in the input layer structure information, and stores the delay time and simulated reflected waves in the waveform database 8. Repeat until stored (S112, S113).

When actually using an ultrasonic imaging device to set gates for reflected waves from the respective interfaces constituting the laminate, it is sufficient to perform the work as in the second embodiment. Before starting actual work, a waveform simulation is performed using a waveform simulator, and the delay time and simulated reflected waves for each layer are stored in a waveform database. In actual work, the delay time and simulated reflected wave for each laminated section stored in the waveform database are called up, and a time gate is set around the simulated signal.

In this manner, by using the waveform simulator 10, it is possible to easily and accurately set time gates for each laminated portion without being affected by the skill level of the worker.

<Second embodiment>
In the second embodiment, an ultrasound imaging apparatus 100 incorporating the waveform simulator 10 of the first embodiment will be described.
FIG. 9 is a diagram showing the configuration of an ultrasound imaging apparatus 100 according to the second embodiment.
The ultrasound imaging apparatus 100 includes a waveform simulator 10 including a material database 7 and a waveform database 8 , an ultrasound probe 50 , a probe driving section 40 that drives the ultrasound probe 50 , and a control device 30 . The control device 30 includes an input section 9, a scan control section 31 that scans and controls the probe drive section 40, a gate information input section 32, a transmission/reception control section 33 that exchanges signals with the probe, and a gate setting section 34. , an image generation section 35 , and a display section 36 . Note that the input unit 9 is shared by the ultrasound imaging device and the waveform simulator.

The ultrasonic imaging device 100 irradiates an inspection range of a target object with ultrasonic waves at irradiation points set at predetermined intervals via an ultrasonic probe 50, obtains the reflected waves, and extracts the reflected waves from among the reflected waves. Extract the interface echo that shows the waveform of the joint interface to be inspected, convert the signal intensity of the interface echo to a positive integer value (0 to 255), and generate pixelated information at all irradiation points or at specific locations. An image of the bonding interface is generated based on the generated pixelization information of the irradiation point to find defects.

The ultrasound probe 50 includes an encoder 51 that detects the scanning position of the ultrasound probe 50, and a piezoelectric element 52 that mutually converts electrical signals and ultrasound signals. The piezoelectric element 52 is, for example, a single focus type ultrasonic sensor.

The control device 30 includes an input section 9, a scan control section 31 that scans and controls the probe drive section 40, a gate information input section 32, a transmission/reception control section 33 that exchanges signals with the probe, and a gate setting section 34. , an image generation section 35 , and a display section 36 . Note that the input unit 9 is shared by the ultrasound imaging device 100 and the waveform simulator 10.

The probe driving section 40 controls the scanning position of the ultrasound probe 50 using a mechanical control section 41 , an X-axis scanner 42 , a Y-axis scanner 43 , and a Z-axis scanner 44 . Receive scanning position information.

The piezoelectric element 52 has electrodes attached to both sides of a piezoelectric film, and is made of zinc oxide (ZnO), ceramics, fluorine-based copolymer, or the like. The piezoelectric element 52 transmits ultrasonic waves from the piezoelectric film when a voltage is applied between both electrodes. Further, the piezoelectric element 52 converts the echo wave (received wave) received by the piezoelectric film into a received signal that is a voltage generated between the two electrodes.

Water 61 is poured into the water tank 60, and a subject 62 is placed submerged in the water 61. Water 61 in the water tank 60 is a propagation medium necessary for efficiently propagating the ultrasonic waves emitted from the opening surface at the lower end of the ultrasonic probe 50 (ultrasonic probe) into the interior of the subject 62. It is a liquid substance. The object 62 is, for example, a semiconductor wafer or a semiconductor package having a plurality of layer structures.

The ultrasonic probe 50 is immersed in water 61 filled in a water tank 60 and is disposed so as to face the upper part of the subject 62 in the Z direction at a predetermined distance.

The ultrasonic probe 50 can be freely moved in the XYZ directions by the probe drive unit 40. For example, the ultrasound probe 50 scans the subject 62 in the X-axis direction from the starting point (one end point) to the end point (the other end point) at a predetermined speed while irradiating the subject 62 with ultrasound. When the ultrasonic probe 50 reaches the end point, the probe is moved a predetermined amount in the Y-axis direction and scans in the X-axis direction from the viewpoint to the end point in the opposite direction at a predetermined speed.

Based on this movement, the ultrasonic probe 50 scans a predetermined measurement range on the surface of the subject 62, transmits ultrasonic waves, and generates reflected echo waves at a plurality of preset measurement points within the measurement range. can be received, and defects in the internal structure included in the measurement range can be visualized and inspected.

The ultrasound imaging device 100 is an ultrasound imaging device that includes a waveform simulator 10 and a display section 36, and inputs layer structure information of the laminate from the input section 9 and provides the layer structure information to the waveform simulator 10. Then, the delay times and simulated reflected waves of all the laminated parts constituting the laminated body are calculated based on the layer structure information, stored in the waveform database 8, and displayed on the display part 36 by the display number selection part 38 (FIG. 11). Obtain the display number selected in (Reference), use the display number as a search key to extract the delay time and simulated reflected wave of the laminated part corresponding to the display number, and display it on the display unit 36 with the horizontal axis as the time axis and the vertical axis as the time axis. The simulated reflected wave is displayed at a position delayed by the delay time on a two-dimensional plane set with the amplitude axis being .

The gate setting operation by the ultrasound imaging device 100 will be explained.
FIG. 10 is a flowchart showing processing S120 of the ultrasound imaging apparatus 100 according to the second embodiment. FIG. 11 is a diagram showing an example of a simulated reflected wave displayed on the display unit 36.
The ultrasound imaging apparatus 100 inputs layer structure information of the laminate to be inspected from the input unit 9 (S121). Based on the input layer structure information, a waveform simulation is performed to calculate the delay times and simulated reflected waves of all the laminated parts and store them in the waveform database 8 (S122).

The ultrasound imaging apparatus 100 acquires the display number of the laminated section to be the target laminated section from the display number selection section 38 in the display section 36, and displays a simulated reflected wave corresponding to the display number (S123). Then, the worker sets the gate in the display section 36, stores the gate information in the gate information storage section 70 (S124), and ends the process.

FIG. 11 shows a diagram in which the third layer of simulated reflected waves is displayed on the display section. A display number indicating which laminated part the target laminated part is is acquired from the display number selection part 38 displayed on the display part 36. Using the acquired display number as a search key, the delay time and simulated reflected wave corresponding to the display number are extracted from the waveform database 8. In FIG. 11, an example is shown in which the target laminated section is input as the third one from the display number selection section. A two-dimensional plane 37 with a time axis set on the horizontal axis and an amplitude axis set on the vertical axis is set on the display unit 36, and a simulated reflected wave is displayed at the position of the extracted delay time. Note that a simulated signal 39 generated by the simulated signal generation section 5 is shown on the left side of FIG. 11 for reference.

The worker traces the peripheral part of the simulated reflected wave displayed on the display unit 36, including the peak value of the simulated reflected wave, using the pointing device connected to the ultrasound imaging device 100. As the gate setting section 34 of the stacked section corresponding to , the temporal position and shape are stored in the gate information storage section 70 in association with the display number.

By performing these processes on all the laminated parts, gate information for all the laminated parts can be stored in the gate information storage section.

When actually inspecting a laminate, the worker extracts gate setting information from the gate information storage unit 70 using the number of the target laminate, that is, the display number, as a search key, and displays the gate information of the target laminate to be inspected. A gate is set in section 36. In this way, a highly accurate gate can be easily set for the target interface without being affected by skill level.

As described above, simulated reflected waves corresponding to all the laminated parts included in the input layer structure information are calculated and stored in the waveform database 8, and gate information corresponding to all the laminated parts is calculated. and stored in the gate information storage section 70. The ultrasound imaging device 100 calls all of the simulated reflected waves and the corresponding gate information in response to instructions from the worker, and superimposes all of the simulated reflected waves into a single image, taking into account the delay time of each simulated reflected wave. Two simulated reflected waves are constructed and displayed in a two-dimensional space set on the display section 36. Note that when displaying the superimposed simulated reflected waves in a two-dimensional space, the worker displays them according to instructions so that each simulated reflected wave can be distinguished from other simulated reflected waves. The method for distinguishing may be by color coding or by displaying thick lines and thin lines alternately. In this case, a method for distinguishing between images is built into the ultrasound imaging device in advance. FIG. 12 shows a diagram showing superimposed simulated reflected waves, and in this example, each simulated reflected wave is distinguished by shading.

The timing for displaying the superimposed simulated reflected waves can be processed by receiving instructions from the worker, or automatically at the timing when the simulated reflected waves and gate information corresponding to all laminated parts are stored. You may.

<Waveform simulator screen example>
The features of the waveform simulator 10 will be further explained.
FIG. 13A is a diagram showing an example of a propagation path where reflection occurs only in a specific layer. FIG. 13B is a diagram showing waveform data calculated on a propagation path where reflection occurs only in a specific layer. The waveform simulator 10 of this embodiment can show, for example, a plurality of propagation paths in which reflection occurs only in a specific layer. When considering reflection at interface 1 in FIG. 13A, path 1 is a case of one reflection at interface 1. Path 2 is a case where the light is reflected at interface 1, reflected at interface 0, and further reflected at interface 1. Path 3 is a case where the light is reflected at interface 1, reflected at interface 0, further reflected at interface 1, reflected at interface 0, and then reflected at interface 1. Therefore, if the operator wants to know the expected reflection waveform of only a specific layer, it can be displayed as shown in FIG. 13B.

FIG. 14 is a diagram showing an example screen of the waveform simulator 10. The waveform simulation screen includes a layer structure input screen, a simulation waveform display section, and the like. In the case of the comparative example (method of Patent Document 1), only the entire waveform (thin line) indicated by reference numeral 81 is displayed, so it was unclear from which interface the reflection occurred. On the other hand, according to the waveform simulator 10 of the present embodiment, for example, if the operator wants to know the reflected wave of the interface 1, the specific interface waveform 82 (thick line, actually a green line) can be displayed. I can do it. Therefore, for example, the operator can easily set the time gate in accordance with the reflected wave of the interface 1. Furthermore, when displaying the simulated reflected wave, it is displayed on the two-dimensional plane in the color specified on the layer structure input screen. Therefore, the operator can easily determine which interface the reflected wave is from.

<Hardware configuration>
FIG. 15 is a diagram showing the hardware configuration of the waveform simulator 10 and the like. The computer 1200 shown in FIG. 15 includes the input section 9 shown in FIG. 1, the processing sections (first processing section 1, second processing section 2, third processing section 3, and fourth processing section 4), This is one of the implementation forms of the generation unit 5, waveform conversion unit 6, material database 7, and waveform database 8. Note that each part may be realized by a plurality of computers 1200.

The computer 1200 includes a memory 1201, a processor 1202, a storage device 1203 such as an HD (Hard Disk), a communication unit 1204 such as an NIC (Network Interface Card), a user interface unit 1205, and the like. Note that a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) can be considered as an example of a processor, but any other semiconductor device may be used as long as it is a main body that executes predetermined processing.

Then, the program stored in the storage device 1203 is loaded into the memory 1201, and the loaded program is executed by the processor 1202. As a result, the functions of each processing section, the simulated signal generation section 5, the waveform conversion section 6, the material database 7, and the waveform database 8 shown in FIG. 1 are realized. The computer 1200 may have a display, a touch panel, a mouse, and a keyboard as a user interface unit 1205.

The waveform simulator 10 of this embodiment described above mainly has the following features.
(1) A waveform simulator that simulates the reflected waves that are reflected back at the target interface, which indicates the bottom surface of the target stacked section, which indicates the desired stacked section, when ultrasonic waves are irradiated to a stacked body having a multilayer structure. Then, the layer structure information including the material and thickness of each laminated part constituting the laminate is inputted, and based on the layer structure information 22 and the material database 7, ultrasonic waves are transmitted from the probe (ultrasonic probe 50) to the laminate. a first processing unit 1 that performs a first process of calculating the delay time from when the ultrasonic wave is irradiated to the probe until the probe receives the reflected wave from the target interface; and after the ultrasonic wave is output from the probe and reaches the target interface. a second processing unit 2 that performs a second process to calculate the first transmittance until the ultrasonic wave is reflected inside the target laminated part; and a fourth processing unit 4 that performs a fourth process of calculating a second transmittance until the reflected wave reaches the probe from the target interface.

(2) The waveform simulator according to (1) above, which includes a simulated signal generation section 5 that generates a simulated signal corresponding to an ultrasonic wave, and has a delay time in all laminated parts and a first waveform in all laminated parts. a simulated reflected wave calculated by calculating the transmittance, the reflectance, and the second transmittance, multiplying these values to calculate an amplitude change rate for the simulated signal, and multiplying the simulated signal by the amplitude change rate; is stored in the storage unit (waveform database 8).

According to the present embodiment, when a laminate is irradiated with ultrasonic waves, a desired The reflected wave reflected from the interface can be found. Therefore, the operator can easily set a highly accurate gate (time gate) for the target interface without being affected by the level of skill.

As mentioned above, when a laminate is irradiated with ultrasonic waves, the waveform simulator generates a simulated reflected wave that simulates the reflected wave from the target interface, and applies an appropriate gate to the reflected wave from the target interface. The present invention supports the setting work and allows the work to be performed quickly without being affected by the skill level of the operator, greatly improving the efficiency of inspecting the presence or absence of defects in the laminate.

1 First processing section 2 Second processing section 3 Third processing section 4 Fourth processing section 5 Simulated signal generation section 6 Waveform conversion section 7 Material database 8 Waveform database (storage section)
9 Input section 10 Waveform simulator 21 Laminated structure 22 Layer structure information 30 Control device 31 Scanning control section 32 Gate information input section 33 Transmission/reception control section 34 Gate setting section 35 Image generation section 36 Display section 37 Two-dimensional plane 38 Display number selection section 39 Simulated signal 40 Probe drive section 41 Mechanical control section 42 X-axis scanner 43 Y-axis scanner 44 Z-axis scanner 50 Ultrasonic probe (probe)
51 Encoder 52 Piezoelectric element 60 Water tank 61 Water 62 Subject 70 Gate information storage section 100 Ultrasonic imaging device L1 1st layer L2 2nd layer L3 3rd layer L4 4th layer L5 5th layer S100 Processing (waveform simulator processing)
S120 Processing (processing of ultrasound imaging device)
Z acoustic impedance Zn, Z _n acoustic impedance of the nth layer

Claims (10)

A waveform simulator that simulates a reflected wave that is reflected and returned at a target interface indicating the bottom surface of a target stacked section indicating a desired stacked section when ultrasonic waves are irradiated to a stacked body having a plurality of layered structures, comprising:
Layer structure information including the material and thickness of each of the laminated parts constituting the laminate is input, and based on the layer structure information and material database, the thickness and sound velocity of each of the laminated parts are used to transmit the ultrasonic wave from the probe. a first processing unit that performs a first process of calculating a delay time from irradiating the laminate with a sound wave until the probe receives the reflected wave from the target interface;
a second processing unit that performs a second process of calculating a first transmittance from when the ultrasonic wave is output from the probe until it reaches the target interface using the sound velocity and density of each of the laminated parts; and,
a third processing unit that performs a third process of calculating a reflectance of reflection of the ultrasonic wave generated inside the target laminated portion using the sound speed and density of each of the laminated portions ;
a fourth processing unit that performs a fourth process of calculating a second transmittance until the reflected wave reaches the probe from the target interface using the sound speed and density of each of the laminated parts ; A waveform simulator characterized by: The waveform simulator according to claim 1,
comprising a simulated signal generation unit that generates a simulated signal corresponding to the ultrasound,
The delay time in all the laminated parts, the first transmittance, the reflectance, and the second transmittance in all the laminated parts are calculated, and these values are multiplied to obtain the simulated signal. A waveform simulator comprising: calculating a rate of change in amplitude for a given amplitude change rate, and storing a simulated reflected wave calculated by multiplying the rate of change in amplitude by the simulated signal in a storage unit. The waveform simulator according to claim 2,
In the first process, extracting V, which is the sound velocity of each laminated portion, from the material database using the material of each laminated portion as a search key,
When the thickness of each laminated part in the layer structure information is D, the number of laminated layers of the laminated body up to the target interface is n, and k is a variable from 0 to n,
A waveform simulator characterized in that the delay time is calculated by: The waveform simulator according to claim 2,
In the second process, extracting the acoustic impedance Z of each of the laminated parts from the material database using the material of each of the laminated parts as a search key,
When the number of layers of the laminate up to the target interface is n, and the acoustic impedance of the liquid medium is Z ₀ ,
(first transmittance)
=(2(Z ₁ )/(Z ₀ +Z ₁ ))×・・×(2Z _n /(Z _n−1 +Z _n ))
A waveform simulator, characterized in that the first transmittance is calculated by: The waveform simulator according to claim 2,
In the third process, when the target laminated portion is nth, the acoustic impedance of the n-1st, nth, and n+1th laminated portions is searched for the material of each of the laminated portions. When the acoustic impedance Z of each of the laminated parts is extracted from the material database, and the number of reflections occurring inside the target laminated part is 5,
(The above reflectance)=((Z _n+1 )−Z _n ))/((Z _n+1 )+Z _n ) ³
×((Z _n−1 )−Z _n )/((Z _n−1 )+Z _n ) ²
A waveform simulator, characterized in that the reflectance is calculated by: The waveform simulator according to claim 2,
In the fourth process, extracting the acoustic impedance Z of each of the laminated parts from the material database using the material of each of the laminated parts as a search key,
When the number of layers of the laminate up to the target interface is n, and the acoustic impedance of the liquid medium is Z ₀ ,
(Second transmittance)
=(2(Z ₀ )/(Z ₀ +Z ₁ ))×・・×(2(Z _n-1 )/(Z _n-1 +Z _n ))
A waveform simulator, characterized in that the second transmittance is calculated by: The waveform simulator according to any one of claims 2 to 6,
An ultrasound imaging device comprising a display section,
The layer structure information of the laminate is inputted from an input section, the layer structure information is given to the waveform simulator, and the delay time of all the laminate parts constituting the laminate is determined based on the layer structure information. The simulated reflected wave is calculated and stored in a waveform database, the display number selected in the display number selection section displayed on the display section is obtained, and the laminated layer corresponding to the display number is obtained using the display number as a search key. The delay time and the simulated reflected wave of the section are extracted, and the simulated wave is displayed at a position delayed by the delay time on a two-dimensional plane set on the display section with the horizontal axis as the time axis and the vertical axis as the amplitude axis. An ultrasound imaging device characterized by displaying reflected waves. The ultrasound imaging device according to claim 7,
The ultrasound imaging apparatus further includes a pointing device, sets a gate in a range traced on the display section by the pointing device, uses the position and shape of the gate as gate information, and displays the laminated section corresponding to the display number. An ultrasound imaging device characterized in that gate information is stored in a gate information storage unit in association with a gate information storage unit. The ultrasound imaging device according to claim 8,
The simulated reflected waves corresponding to all the laminated parts included in the layer structure information are stored in the waveform database, the gate information is stored in the gate information storage section, and the simulated reflected waves corresponding to all the laminated parts included in the layer structure information are stored in the waveform database. The simulated reflected waves and the delay time are called, the simulated reflected waves of all the laminated parts are superimposed to form one simulated reflected wave, and the reflected waves of each laminated part are combined with the reflected waves of the other laminated parts. An ultrasonic imaging device characterized by displaying the reflected waves on the two-dimensional plane in distinction from the reflected waves. The ultrasound imaging device according to claim 7,
An ultrasound imaging apparatus characterized in that when displaying the simulated reflected wave, the simulated reflected wave is displayed on the display unit in a color specified on a layer structure input screen.

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