Automatic focusing device and method of ultrasonic scanning microscope

Abstract

The invention provides an automatic focusing device and method for an ultrasonic scanning microscope, and the device comprises a motion platform module, a distance measurement module, and an ultrasonic probe module. The motion platform module comprises a scanning shaft, a focusing shaft and a stepping shaft, the scanning shaft is arranged in the X-axis direction, the stepping shaft is arranged in the Y-axis direction, the focusing shaft is arranged in the Z-axis direction, and the motion platform module is used for focusing the ultrasonic module probe; the distance measuring module is mounted on the scanning shaft or the focusing shaft and is used for measuring the surface height of the measured workpiece; and the ultrasonic probe module is mounted on the focusing shaft and is used for transmitting and receiving ultrasonic waves to detect the detected workpiece. According to the invention, the distance measuring module is adopted to obtain the height change of the surface of the measured workpiece, the heights of the focusing shaft and the ultrasonic probe module are automatically adjusted in real time, the probe and the measured workpiece are always kept on the optimal focal plane, automatic focusing is realized, and the ultrasonic scanning image quality is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of ultrasonic scanning detection, and in particular to an automatic focusing device and method for an ultrasonic scanning microscope. Background Art

[0002] Traditional ultrasonic microscope inspection equipment needs to perform a focusing process first, adjust the distance between the probe and the workpiece to the optimal focal plane height, and then scan. During the entire scanning process, the probe height remains unchanged and is no longer adjusted.

[0003] The traditional equipment and methods of focusing before scanning are not very suitable when the inspection surface of the workpiece is tilted, warped, or arched beyond the focal depth range of the probe. During the scanning process, the probe has the best focal height only near the focus point, and other positions are out of focus, which causes the quality of the scanned image to deteriorate, affecting the accuracy of the ultrasonic scanning test results. Summary of the invention

[0004] In view of the defects in the prior art, the purpose of the present invention is to provide an automatic focusing device and method for an ultrasonic scanning microscope.

[0005] To achieve the above object, according to one aspect of the present disclosure, there is provided an automatic focusing device for an ultrasonic scanning microscope, comprising:

[0006] Motion table module, distance measurement module, ultrasound probe module;

[0007] The motion stage module includes a scanning axis, a focusing axis and a stepping axis, wherein the scanning axis is arranged along the X-axis direction, the stepping axis is arranged along the Y-axis direction, the focusing axis is arranged along the Z-axis direction, the scanning axis is perpendicular to the stepping axis and arranged on the stepping axis, the focusing axis is perpendicular to the scanning axis and arranged on the scanning axis, and the motion stage module is used to adjust the positions of the ranging module and the ultrasound probe module and focus the ultrasound module probe;

[0008] The distance measuring module is installed on the scanning axis or the focusing axis, and the distance measuring module is used to measure the surface height of the workpiece being measured;

[0009] The ultrasonic probe module is mounted on the focusing axis, the ultrasonic probe module and the distance measuring module are arranged in parallel with each other, and the ultrasonic probe module is used to transmit and receive ultrasonic waves to detect the workpiece to be measured.

[0010] Optionally, the scanning axis, the focusing axis, the ranging module and the ultrasonic probe module move along the Y-axis direction on the stepping axis;

[0011] The focusing axis, the ranging module and the ultrasonic probe module move along the X-axis direction on the scanning axis;

[0012] If the distance measuring module is installed on the focusing axis, the distance measuring module moves along the Z-axis direction on the focusing axis;

[0013] The ultrasonic probe module moves along the Z-axis direction on the focusing axis.

[0014] Optionally, it further includes a first connecting plate and a second connecting plate, the focusing axis is fixed to the scanning axis through the first connecting plate, the ultrasound probe module is fixed to the second connecting plate, and the ultrasound probe module is installed on the focusing axis through the second connecting plate.

[0015] Optionally, a third connecting plate is further included, the ranging module is fixed on the third connecting plate, and the ranging module and the third connecting plate are installed on the scanning axis through the first connecting plate.

[0016] Optionally, a water tank module is further included, wherein the water tank module is arranged at the bottom of the motion platform module, and the water tank module is used to place the workpiece to be measured.

[0017] According to a second aspect of the present disclosure, there is provided an automatic focusing method for an ultrasonic scanning microscope, comprising:

[0018] According to the preset scanning mode, the motion stage module is used to drive the distance measurement module to perform a pre-scanning operation to determine each scanning position and height comparison table of the upper surface of the workpiece to be measured;

[0019] According to the preset scanning mode, the motion stage module is used to drive the ultrasonic probe module to perform a formal scanning operation, and the target height of the focus axis is determined according to a comparison table of each scanning position and height of the upper surface of the workpiece to be measured and an optimal focal plane spacing;

[0020] sending the target height of the focus axis to a motion control system;

[0021] Using the motion control system to control the focus axis of the motion stage module to move to a target height of the focus axis;

[0022] At the target height of the focusing axis, the ultrasonic probe module is used to detect the workpiece.

[0023] Optionally, the preset scanning modes include: a two-round scanning mode, a line-by-line scanning mode and a parallel scanning mode.

[0024] Optionally, the motion stage module is used to drive the distance measurement module to perform a pre-scanning operation to determine each scanning position and height comparison table of the upper surface of the workpiece to be measured, including:

[0025] The moving stage module is used to drive the distance measuring module to perform the pre-scanning operation on the upper surface of the workpiece to be measured according to the scanning trajectory corresponding to the preset scanning mode, read the position coordinates of the scanning axis and the stepping axis, and determine the two-dimensional coordinates of each scanning position on the upper surface of the workpiece to be measured and the distance between the distance measuring module and the upper surface of the workpiece to be measured corresponding to each scanning position;

[0026] Determine the actual height of the upper surface of the workpiece to be measured corresponding to each scanning position according to the distance between the distance measuring module corresponding to each scanning position and the upper surface of the workpiece to be measured and the height of the distance measuring module;

[0027] According to the two-dimensional coordinates of each scanning position on the upper surface of the workpiece to be measured and the actual height of the upper surface of the workpiece to be measured corresponding to each scanning position, a comparison table of each scanning position and height of the upper surface of the workpiece to be measured is determined.

[0028] Optionally, according to the preset scanning mode, the motion stage module is used to drive the ultrasonic probe module to perform a formal scanning operation, and according to each scanning position and height comparison table of the upper surface of the workpiece to be measured and the optimal focal plane spacing, the target height of the focus axis is determined, including:

[0029] The motion stage module is used to drive the ultrasonic probe module to perform the formal scanning operation on the upper surface of the workpiece to be measured according to the scanning trajectory corresponding to the preset scanning mode, read the position coordinates of the scanning axis and the stepping axis, and determine the two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured;

[0030] Determine the height corresponding to each formal scanning position on the upper surface of the workpiece to be measured according to the two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured and the comparison table between each scanning position and height on the upper surface of the workpiece to be measured;

[0031] The target height of the focus axis is determined according to the height corresponding to each formal scanning position of the upper surface of the workpiece to be measured and the optimal focal plane distance.

[0032] Optionally, determining the target height of the focus axis according to the height corresponding to each formal scanning position of the upper surface of the workpiece to be measured and the optimal focal plane distance includes:

[0033] The height corresponding to each formal scanning position on the upper surface of the workpiece to be measured is summed with the optimal focal plane distance to determine the target height of the focus axis.

[0034] Compared with the prior art, the embodiments of the present disclosure have at least one of the following beneficial effects:

[0035] Through the above technical solution, the motion stage module is provided with a scanning axis arranged along the X-axis direction, a stepping axis arranged along the Y-axis direction and a focusing axis arranged along the Z-axis direction. The ranging module is used to measure the surface height of the workpiece to be measured. When the surface height of the workpiece to be measured changes, the motion stage module is used to adjust the positions of the ranging module and the ultrasonic probe module in real time to achieve automatic focusing of the ultrasonic probe module, always keep the ultrasonic probe module and the workpiece to be measured at the optimal focal plane, and improve the quality of ultrasonic scanning images. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other features, objects and advantages of the present disclosure will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0037] Figure 1 The figure is a schematic diagram of the overall structure of an automatic focusing device for an ultrasonic scanning microscope according to an exemplary embodiment.

[0038] Figure 2 It is a schematic structural diagram of a sports platform module according to an exemplary embodiment.

[0039] Figure 3 The figure is a schematic structural diagram of a distance measurement module according to an exemplary embodiment.

[0040] Figure 4 is a schematic structural diagram of an ultrasound probe module according to an exemplary embodiment.

[0041] Figure 5 It is a schematic structural diagram of a water tank module according to an exemplary embodiment.

[0042] Figure 6 It is a schematic structural diagram of a cantilevered sports platform module according to an exemplary embodiment.

[0043] Figure 7 It is a schematic structural diagram of a turntable type sports table module according to an exemplary embodiment.

[0044] Figure 8 It is a schematic structural diagram of a cam follower reciprocating motion table module according to an exemplary embodiment.

[0045] Fig. 9 The figure is a schematic diagram showing the working principle of an automatic focusing device of an ultrasonic scanning microscope according to an exemplary embodiment.

[0046] Fig.10 The figure is a schematic diagram showing a defocusing state of a tilted workpiece under detection without automatic focusing according to an exemplary embodiment.

[0047] Fig.11 The figure is a schematic diagram showing a defocused state of a warping workpiece without automatic focusing according to an exemplary embodiment.

[0048] Fig.12 The present invention is a schematic diagram showing an automatic focusing device using an ultrasonic scanning microscope to adapt to the inclination of the surface of a workpiece being measured according to an exemplary embodiment.

[0049] Fig.13 The present invention is a schematic diagram showing an automatic focusing device using an ultrasonic scanning microscope to adapt to the warping of the surface of a workpiece under test according to an exemplary embodiment.

[0050] Fig.14 is a schematic diagram of a scanning trajectory of a two-round scanning mode according to an exemplary embodiment.

[0051] Fig.15 is a schematic diagram of a scanning trajectory of a line-by-line scanning mode according to an exemplary embodiment.

[0052] Fig.16 is a schematic diagram of a scanning trajectory of a parallel scanning mode according to an exemplary embodiment.

[0053] Fig.17 The figure is a schematic diagram of a scanning trajectory of an ultrasonic probe module also serving as a distance measurement module in a two-round scanning mode according to an exemplary embodiment.

[0054] Fig.18 The figure is a schematic diagram of a scanning trajectory of an ultrasonic probe module also serving as a distance measurement module in a line-by-line scanning mode according to an exemplary embodiment.

[0055] Fig.19 The figure is a schematic diagram of a scanning trajectory of an ultrasonic probe module also serving as a distance measurement module in a parallel scanning mode according to an exemplary embodiment.

[0056] Fig. 20 The present invention is a flow chart of an automatic focusing method of an ultrasonic scanning microscope according to an exemplary embodiment.

[0057] Description of Reference Numerals

[0058] 100 Automatic focusing device for ultrasonic scanning microscope

[0059] 110 Sports Station Module

[0060] 111 Scan axis

[0061] 112 Stepper Axis

[0062] 113 Focus axis

[0063] 120 Distance Measurement Module

[0064] 130 Ultrasound probe module

[0065] 140 First connecting plate

[0066] 150 Second connecting plate

[0067] 160 Third connecting plate

[0068] 170 Sink Module

[0069] 180 Workpiece under test

[0070] 190 Turntable

[0071] 200 Cam module

[0072] 201 Cam

[0073] 202 Putter DETAILED DESCRIPTION

[0074] The present disclosure is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present disclosure, but are not intended to limit the present disclosure in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present disclosure. These all fall within the scope of protection of the present disclosure.

[0075] Figure 1 The figure is a schematic diagram of the overall structure of an automatic focusing device for an ultrasonic scanning microscope according to an exemplary embodiment.

[0076] like Figure 1 As shown, the present disclosure provides an automatic focusing device 100 for an ultrasonic scanning microscope, comprising: a motion stage module 110 , a distance measurement module 120 , and an ultrasonic probe module 130 .

[0077] Among them, the ranging module 120 and the ultrasonic probe module 130 are installed on the moving table module 110. The moving table module 110 is used to drive the ranging module 120 and the ultrasonic probe module 130 to move in the XYZ direction. The ranging module 120 is used to measure the distance between the ranging module 120 and the upper surface of the workpiece 180 to be measured. The ultrasonic probe module 130 is used to transmit and receive ultrasonic waves to perform ultrasonic scanning on the workpiece 180 to facilitate subsequent ultrasonic scanning imaging.

[0078] Figure 2 It is a schematic structural diagram of a sports platform module according to an exemplary embodiment.

[0079] like Figure 2As shown, the motion stage module 110 includes a scanning axis 111, a focusing axis 113 and a stepping axis 112. The scanning axis 111 is arranged along the X-axis direction, the stepping axis 112 is arranged along the Y-axis direction, and the focusing axis 113 is arranged along the Z-axis direction. The scanning axis 111 is perpendicular to the stepping axis 112 and is arranged on the stepping axis 112. The focusing axis 113 is perpendicular to the scanning axis 111 and is arranged on the scanning axis 111. The motion stage module 110 is used to adjust the positions of the ranging module 120 and the ultrasonic probe module 130 and focus the ultrasonic probe module 130.

[0080] The motion stage module 110 of the present disclosure is a gantry motion stage module, which moves the ranging module 120 and the ultrasonic probe module 130 in the XYZ directions to achieve focusing of the ultrasonic probe module 130 .

[0081] like Figure 2 As shown, the gantry motion stage module includes a scanning axis 111, a focusing axis 113 and two stepping axes 112. One end of the scanning axis 111 is arranged on one stepping axis 112, and the other end of the scanning axis 111 is arranged on another stepping axis 112. The scanning axis 111 and the two stepping axes 112 are arranged perpendicular to each other, and the scanning axis 111 can move along the Y axis on the two stepping axes 112. The focusing axis 113 is arranged on the scanning axis 111, and the focusing axis 113 can move along the X axis on the scanning axis 111.

[0082] Figure 3 The figure is a schematic structural diagram of a distance measurement module according to an exemplary embodiment.

[0083] like Figure 1 , Figure 3 As shown, the distance measuring module 120 is installed on the scanning axis 111 or the focusing axis 113 , and the distance measuring module 120 is used to measure the surface height of the workpiece 180 to be measured.

[0084] The surface height of the workpiece 180 measured by the distance measuring module 120 is the surface height in the whole machine coordinate system of the automatic focusing device 100 for an ultrasonic scanning microscope provided in the present disclosure.

[0085] The distance measurement module 120 can be used as a pre-scanning module to achieve a precise distance measurement function. The distance measurement module 120 can specifically adopt a laser distance measurement module, an ultrasonic distance measurement module, an eddy current distance measurement module, or a capacitive distance measurement module.

[0086] Figure 4 is a schematic structural diagram of an ultrasound probe module according to an exemplary embodiment.

[0087] like Figure 1 , Figure 4As shown, the ultrasonic probe module 130 is installed on the focusing axis 113 , and the ultrasonic probe module 130 and the distance measuring module 120 are arranged parallel to each other. The ultrasonic probe module 130 is used to transmit and receive ultrasonic waves to detect the workpiece 180 to be measured.

[0088] The ultrasonic probe module 130 can move up and down along the Z-axis direction along the focusing axis 113, and during the ultrasonic scanning process, it transmits and sends ultrasonic signals and receives ultrasonic echo signals for final imaging.

[0089] Through the above technical solution, the motion stage module 110 is provided with a scanning axis 111 arranged along the X-axis direction, a stepping axis 112 arranged along the Y-axis direction and a focusing axis 113 arranged along the Z-axis direction. The ranging module 120 is used to measure the surface height of the workpiece 180 to be measured. When the surface height of the workpiece 180 to be measured changes, the motion stage module 110 is used to adjust the positions of the ranging module 120 and the ultrasonic probe module 130 in real time to achieve automatic focusing of the ultrasonic probe module 130, always keep the ultrasonic probe module 130 and the workpiece 180 to be measured at the optimal focal plane, and improve the quality of ultrasonic scanning images.

[0090] In a possible embodiment, under the adjustment of the motion stage module 110 , the scanning axis 111 , the focusing axis 113 , the distance measurement module 120 , and the ultrasound probe module 130 move along the Y-axis direction on the stepping axis 112 .

[0091] The focus axis 113 , the distance measurement module 120 , and the ultrasound probe module 130 move along the X-axis direction on the scanning axis 111 .

[0092] If the distance measuring module 120 is disposed on the focus axis 113 , the distance measuring module 120 moves along the Z-axis direction on the focus axis 113 .

[0093] The ultrasound probe module 130 moves along the Z-axis direction on the focus axis 113 .

[0094] If the distance measuring module 120 is disposed on the scanning axis 111 , the distance measuring module 120 will not move along the Z-axis direction.

[0095] Through the adjustment of the motion stage module 110 , the ultrasound probe module 130 is adjusted to a focus position.

[0096] Such as 1. Figure 4 As shown, in a possible embodiment, the automatic focusing device 100 of the ultrasonic scanning microscope also includes a first connecting plate 140 and a second connecting plate 150. The focusing axis 113 is fixed to the scanning axis 111 through the first connecting plate 140, the ultrasonic probe module 130 is fixed to the second connecting plate 150, and the ultrasonic probe module 130 is installed on the focusing axis 113 through the second connecting plate 150.

[0097] The first connecting plate 140 can slide along the X-axis direction on the scanning axis 111. The ultrasonic probe module 130 passes through the two bottom surfaces of the second connecting plate 150, and one side surface of the second connecting plate 150 is fixed on the focusing axis 113, so that the ultrasonic probe module 130 is installed on the focusing axis 113 through the second connecting plate 150.

[0098] As an example, the first connecting plate 140 , the focus axis 113 , the second connecting plate 150 , and the ultrasound probe module 130 can move together along the X-axis direction on the scanning axis 111 .

[0099] As another example, the ultrasound probe module 130 and the second connection plate 150 can move along the Z-axis direction on the first connection plate 140 together with the focus axis 113 .

[0100] like Figure 1 , Figure 3 As shown, in a possible embodiment, the automatic focusing device 100 of the ultrasonic scanning microscope further includes a third connecting plate 160, the ranging module 120 is fixed on the third connecting plate 160, and the ranging module 120 and the third connecting plate 160 are installed on the scanning axis 111 through the first connecting plate 140.

[0101] The distance measuring module 120 passes through two bottom surfaces of the third connecting plate 160 , and one side surface of the third connecting plate 160 is fixed on the first connecting plate 140 .

[0102] As an example, the distance measuring module 120 and the third connecting plate 160 can move along the X-axis direction on the scanning axis 111 along the first connecting plate 140 .

[0103] In another possible embodiment, the ranging module 120 can also be installed on the focusing axis 113 through the third connecting plate 160. If the ranging module 120 is installed on the focusing axis 113 through the third connecting plate 160, the ranging module 120 can move along the Z-axis direction on the focusing axis 113 together with the ultrasound probe module 130.

[0104] When the distance measuring module 120 is installed on the focusing axis 113 through the third connecting plate 160 , the distance measuring module 120 and the ultrasonic probe module 130 are still arranged parallel to each other.

[0105] Figure 5 It is a schematic structural diagram of a water tank module according to an exemplary embodiment.

[0106] like Figure 5As shown, in a possible embodiment, an automatic focusing device 100 for an ultrasonic scanning microscope may further include a water tank module 170 . The water tank module 170 is disposed at the bottom of the moving stage module 110 . The water tank module 170 is used to place a workpiece 180 to be measured.

[0107] If a gantry motion table module is used, the water tank module 170 can be disposed between the two stepping axes 112 and below the scanning axis 111 and the focusing axis 113. The water tank module 170 can contain water or other liquids, and the workpiece 180 to be tested is placed in the liquid in the water tank module 170 for ultrasonic testing.

[0108] Figure 6 It is a schematic structural diagram of a cantilevered sports platform module according to an exemplary embodiment.

[0109] like Figure 6 As shown, in a possible embodiment, the motion table module 110 of the present disclosure may also adopt a cantilever motion table module.

[0110] The cantilever motion stage module includes a scanning axis 111, a stepping axis 112, and a focusing axis 113, wherein the scanning axis 111 is arranged along the X-axis direction, the stepping axis 112 is arranged along the Y-axis direction, and the focusing axis 113 is arranged along the Z-axis direction. The scanning axis 111 is perpendicular to the stepping axis 112 and is arranged on the stepping axis 112. One end of the scanning axis 111 is arranged on the stepping axis 112, and the other end of 111 is a free end after scanning. The scanning axis 111 can move along the Y-axis direction on the stepping axis 112. The focusing axis 113 is perpendicular to the scanning axis 111 and is arranged on the scanning axis 111. The focusing axis 113 can move along the X-axis direction with the scanning axis 111, and the focusing axis 113 can also move along the Z-axis direction.

[0111] If the motion stage module 110 adopts a cantilever motion stage module, in the automatic focusing device 100 of the ultrasonic scanning microscope, the focus axis 113 is fixed on the scanning axis 111 through the first connecting plate 140, the ultrasonic probe module 130 passes through the two bottom surfaces of the second connecting plate 150, the ultrasonic probe module 130 is fixed on the second connecting plate 150, and one side surface of the second connecting plate 150 is fixed on the focus axis 113, thereby, the ultrasonic probe module 130 is installed on the focus axis 113 through the second connecting plate 150. The distance measuring module 120 passes through the two bottom surfaces of the third connecting plate 160, the distance measuring module 120 is fixed on the third connecting plate 160, and one side surface of the third connecting plate 160 is fixed on the first connecting plate 140, thereby, the distance measuring module 120 is installed on the scanning axis 111 through the third connecting plate 160 and the first connecting plate 140.

[0112] The distance measurement module 120 and the ultrasonic probe module 130 are arranged parallel to each other.

[0113] The water tank module 170 may be disposed on one side of the stepping axis 112 , below the scanning axis 111 and the focusing axis 113 , and the workpiece 180 to be measured is disposed in the liquid inside the water tank module 170 .

[0114] Figure 7 It is a schematic structural diagram of a turntable type sports table module according to an exemplary embodiment.

[0115] like Figure 7 As shown, in a possible embodiment, the sports table module 110 of the present disclosure may also adopt a turntable type sports table module.

[0116] The turntable motion stage module includes a focusing axis 113 , a scanning axis 111 and a turntable 190 . The scanning axis 111 is arranged along the X-axis direction, the focusing axis 113 is arranged along the Z-axis direction, and the focusing axis 113 is perpendicular to the scanning axis 111 and arranged on the scanning axis 111 .

[0117] If a turntable motion stage module is used, in the automatic focusing device 100 of the ultrasonic scanning microscope, the focus axis 113 is fixed to the scanning axis 111 through the first connecting plate 140, the ultrasonic probe module 130 passes through the two bottom surfaces of the second connecting plate 150, the ultrasonic probe module 130 is fixed to the second connecting plate 150, and one side surface of the second connecting plate 150 is fixed to the focus axis 113, thereby, the ultrasonic probe module 130 is installed on the focus axis 113 through the second connecting plate 150. The distance measuring module 120 passes through the two bottom surfaces of the third connecting plate 160, the distance measuring module 120 is fixed to the third connecting plate 160, and one side surface of the third connecting plate 160 is fixed to the first connecting plate 140, thereby, the distance measuring module 120 is installed on the scanning axis 111 through the third connecting plate 160 and the first connecting plate 140.

[0118] The distance measurement module 120 and the ultrasonic probe module 130 are arranged parallel to each other.

[0119] The water tank module 170 is disposed below the scanning axis 111 and the focusing axis 113, and the workpiece 180 to be measured is disposed in the liquid inside the water tank module 170. In addition, a turntable 190 is disposed at the bottom of the water tank module 170, and the turntable 190 drives the water tank module 170 to rotate, thereby realizing the movement of the workpiece 180 to be measured in the Y-axis direction.

[0120] Figure 8 It is a schematic structural diagram of a cam follower reciprocating motion table module according to an exemplary embodiment.

[0121] like Figure 8As shown, in a possible embodiment, the motion table module 110 of the present disclosure may also adopt a cam follower reciprocating motion table module.

[0122] like Figure 8 As shown, the cam push rod reciprocating motion stage module includes a scanning axis 111, a stepping axis 112, a focusing axis 113 and a cam module 200. Among them, the scanning axis 111 is arranged along the Y-axis direction, the stepping axis 112 is arranged along the X-axis direction, and the focusing axis 113 is arranged along the Z-axis direction. The focusing axis 113 is perpendicular to the stepping axis 112 and is arranged on the stepping axis 112. The focusing axis 113 can move along the X-axis direction on the stepping axis 112, and the focusing axis 113 itself can move along the Z-axis direction; the scanning axis 111 is arranged below the focusing axis 113 and the stepping axis 112. The cam module 200 includes a cam 201 and a push rod 202, one end of the push rod 202 is connected to the cam 201, and the other end of the push rod 202 is connected to the stepping axis 112. The cam module 200 is used to drive the stepping axis 112 to reciprocate along the X-axis direction.

[0123] If a cam push rod reciprocating motion stage module is used, in the automatic focusing device 100 of the ultrasonic scanning microscope, the focus shaft 113 is fixed to the stepping shaft 112 through the first connecting plate 140, the ultrasonic probe module 130 passes through the two bottom surfaces of the second connecting plate 150, the ultrasonic probe module 130 is fixed to the second connecting plate 150, and one side surface of the second connecting plate 150 is fixed to the focus shaft 113, thereby, the ultrasonic probe module 130 is installed on the focus shaft 113 through the second connecting plate 150. The distance measuring module 120 passes through the two bottom surfaces of the third connecting plate 160, the distance measuring module 120 is fixed to the third connecting plate 160, and one side surface of the third connecting plate 160 is fixed to the first connecting plate 140, thereby, the distance measuring module 120 is installed on the stepping shaft 112 through the third connecting plate 160 and the first connecting plate 140.

[0124] The distance measurement module 120 and the ultrasonic probe module 130 are arranged parallel to each other.

[0125] The water tank module 170 is disposed on the scanning axis 111 , and the scanning axis 111 is used to drive the water tank module 170 to move along the Y-axis direction.

[0126] Fig. 9 The figure is a schematic diagram showing the working principle of an automatic focusing device of an ultrasonic scanning microscope according to an exemplary embodiment.

[0127] like Fig. 9As shown, in a possible embodiment, when the automatic focusing device 100 of the ultrasonic scanning microscope provided by the present invention is used to perform automatic focusing, the moving stage module 110 drives the ranging module 120 to perform a pre-scanning operation on the workpiece 180 to be measured along a scanning trajectory corresponding to a preset scanning mode, and at the same time records the scanning axis 111 (X axis), the stepping axis 112 (Y axis), the height L of the ranging module 120, and the distance S between the ranging module 120 and the surface of the workpiece 180 to be measured. The height L of the ranging module 120 minus the distance S between the ranging module 120 and the surface of the workpiece 180 to be measured is used as the actual height H of the scanning position (X, Y) on the upper surface of the workpiece 180 to be measured, and is recorded in the comparison table to form a comparison table of each scanning position and height of the upper surface of the workpiece 180 to be measured, and used as the target data during the formal scanning operation.

[0128] H=LS

[0129] Wherein, H represents the actual height of the scanning position (X, Y) on the upper surface of the workpiece 180 to be measured, L represents the height of the distance measuring module 120, and S represents the distance between the distance measuring module 120 and the surface of the workpiece 180 to be measured.

[0130] When the moving stage module 110 drives the ranging module 120 to perform a formal scanning operation on the workpiece 180 to be measured along the scanning trajectory corresponding to the preset scanning mode, the current positions of the scanning axis 111 (X axis) and the stepping axis 112 (Y axis) are read, and the comparison table is queried to obtain the actual height H of the upper surface of the workpiece 180 to be measured corresponding to the current position (X, Y), and the optimal focal plane spacing F is superimposed as the target height of the focusing axis 113. The focusing axis 113 is adjusted to the target height position of the focusing axis 113, and the ultrasonic probe module 130 is automatically focused.

[0131] Z=H+F

[0132] Wherein, Z represents the target height of the focus axis 113, H represents the actual height H of the upper surface of the workpiece 180 to be measured corresponding to the current position (X, Y), and F represents the optimal focal plane distance.

[0133] In the present disclosure, the preset scanning modes may include a two-round scanning mode, a line-by-line scanning mode, and a parallel scanning mode. In the two-round scanning mode, the pre-scanning operation and the formal scanning operation respectively perform an S-shaped reciprocating scanning trajectory; in the line-by-line scanning mode, the pre-scanning operation is first performed on each row, and then the formal scanning operation is performed in the opposite direction of the row, and the reciprocating scanning trajectory is performed line by line; in the parallel scanning mode, the pre-scanning operation and the formal scanning operation simultaneously perform the S-shaped scanning trajectory.

[0134] In a possible embodiment, an automatic focusing device 100 for an ultrasonic scanning microscope may also use only the ultrasonic probe module 130 to measure the surface height of the workpiece 180 to be measured, and the ultrasonic probe module 130 may be used to transmit and receive ultrasonic waves to detect the workpiece 180 to be measured, that is, the distance measurement module 120 is omitted, and the ultrasonic probe module 130 is used to replace the distance measurement module 120 to measure the surface height of the workpiece 180 to be measured. When only the ultrasonic probe module 130 is used, a two-round scanning mode, a line-by-line scanning mode, and a parallel scanning mode may also be used, and the ultrasonic probe module 130 may be used to replace the function of the distance measurement module 120.

[0135] Fig.10 1 is a schematic diagram showing a defocusing state of a tilted workpiece 180 to be detected without automatic focusing according to an exemplary embodiment. Fig.11 1 is a schematic diagram showing a defocused state of a workpiece 180 to be tested for warping without automatic focusing according to an exemplary embodiment.

[0136] like Fig.10 , 11 As shown, in the absence of automatic focusing, the ultrasonic probe module 130 has poor adaptability when detecting a workpiece 180 with an inclined, warped, or arched surface. The ultrasonic probe module 130 is at the optimal focal plane height only near the focus and is out of focus at other positions, resulting in a decrease in the quality of the scanned image.

[0137] Fig.12 The present invention is a schematic diagram showing an automatic focusing device using an ultrasonic scanning microscope to adapt to the inclination of the surface of a workpiece being measured according to an exemplary embodiment. Fig.13 The present invention is a schematic diagram showing an automatic focusing device using an ultrasonic scanning microscope to adapt to the warping of the surface of a workpiece under test according to an exemplary embodiment.

[0138] like Fig.12 , 13 As shown, the automatic focusing device 100 of the ultrasonic scanning microscope provided by the present invention can automatically adjust the height of the ultrasonic probe module 130 during the ultrasonic scanning process to adapt to the surface inclination, warping, and arching of the workpiece 180 to be measured, ensure that the ultrasonic probe module 130 and the surface of the workpiece 180 to be measured are always at the effective focusing depth, prevent the surface of the workpiece 180 to be measured from being out of focus, and improve the quality of the scanned image.

[0139] Fig.14 is a schematic diagram of a scanning trajectory of a two-round scanning mode according to an exemplary embodiment.

[0140] like Fig.14 As shown, in a possible embodiment, the working process of the automatic focusing device 100 using an ultrasonic scanning microscope to perform automatic focusing in a two-round scanning mode is as follows:

[0141] like Fig.14 As shown in (a), first, the motion stage module 110 drives the ranging module 120 to perform a round of pre-scanning operation, and scans the entire plane of the workpiece 180 along an S-shaped reciprocating scanning trajectory, records the actual height data of the entire plane of the workpiece 180, and generates a comparison table between each scanning position and height of the upper surface of the workpiece 180.

[0142] like Fig.14 (b) shows, secondly, the motion stage module 110 drives the ultrasonic probe module 130 to perform a round of formal scanning operation along an S-shaped reciprocating scanning trajectory. During the formal scanning operation, the position coordinates of the formal scanning axis 111 and the stepping axis 112 are read in real time to determine the formal scanning position (X, Y). By querying each scanning position and height comparison table of the upper surface of the workpiece 180 to interpolate and calculate the actual height of the surface of the workpiece 180 at the current formal scanning position, the optimal focal plane spacing is superimposed to determine the target height of the focusing axis 113. The motion stage module 110 drives the focusing axis 113 to move to the target height of the focusing axis 113, thereby realizing automatic focusing of the ultrasonic probe module 130.

[0143] Fig.15 is a schematic diagram of a scanning trajectory of a line-by-line scanning mode according to an exemplary embodiment.

[0144] like Fig.15 As shown, in a possible embodiment, the working process of the automatic focusing device 100 using an ultrasonic scanning microscope to perform automatic focusing in a line-by-line scanning mode is as follows:

[0145] like Fig.15 As shown in (a), first, the motion stage module 110 drives the distance measurement module 120 to perform a pre-scan operation on the first row, the stepping axis 112 is fixed at the position of the first row, and the scanning axis 111 moves from left to right along the X-axis to record the actual height data of the surface of the workpiece 180 to be measured in the first row, and generate a comparison table between each scanning position and height of the upper surface of the workpiece 180 to be measured.

[0146] like Fig.15(b) shows, secondly, the motion stage module 110 drives the ultrasonic probe module 130 to perform the formal scanning operation of the first row, moves the ultrasonic probe module 130 to the position of the stepping axis 112 corresponding to the pre-scanning operation of the first row and fixes it, and the scanning axis 111 moves from right to left along the X-axis. During the formal scanning process, the current position of the scanning axis 111 is read in real time to determine the formal scanning position (X, Y). By querying the comparison table of each scanning position and height of the upper surface of the workpiece 180 to interpolate and calculate the actual height of the surface of the workpiece 180 at the current formal scanning position, the optimal focal plane distance is superimposed to determine the target height of the focusing axis 113, and the motion stage module 110 drives the focusing axis 113 to move to the target height of the focusing axis 113.

[0147] like Fig.15 (c) Fig.15 As shown in (d), after the pre-scan and the formal scanning operations of the first row are completed, the stepper axis 112 is moved to the starting point of the second row, and the ranging module 120 and the ultrasonic probe module 130 are driven to cyclically repeat the pre-scan and the formal scanning operations until the ultrasonic scanning of the surface of the entire workpiece 180 is completed, thereby realizing automatic focusing of the ultrasonic probe module 130.

[0148] Fig.16 is a schematic diagram of a scanning trajectory of a parallel scanning mode according to an exemplary embodiment.

[0149] like Fig.16 As shown, in a possible embodiment, the working process of the automatic focusing device 100 using an ultrasonic scanning microscope to perform automatic focusing in a parallel scanning mode is as follows:

[0150] like Fig.16 (a) and Fig.16 As shown in (b), the motion stage module 110 drives the distance measuring module 120 and the ultrasonic probe module 130 to perform the pre-scanning operation and the formal scanning operation simultaneously, and the entire plane of the workpiece 180 to be measured is completely scanned along the S-shaped reciprocating scanning trajectory. Fig.16 As shown in (a), when the ultrasonic probe module 130 is outside the height measured by the ranging module 120, the height of the focus axis 113 remains unchanged, and the height of the ultrasonic probe module 130 remains unchanged, as shown in FIG. Fig.16 As shown in (b), when the ultrasonic probe module 130 is within the height measured by the ranging module 120, an interpolation calculation is performed to determine the target height of the focus axis 113, and the height of the focus axis 113 is adjusted to focus the ultrasonic probe module 130.

[0151] like Fig.16As shown in (b), when the ultrasonic probe module 130 is within the height measured by the ranging module 120, the ranging module 120 performs a pre-scanning operation along the leading S-shaped reciprocating scanning trajectory to continuously record the actual height data of the plane of the workpiece 180 to be measured, and generates a comparison table between each scanning position and the height of the upper surface of the workpiece 180 to be measured. The ultrasonic probe module 130 performs a formal scanning operation along the trailing S-shaped reciprocating scanning trajectory, and reads the position coordinates of the formal scanning axis 111 and the stepping axis 112 in real time to determine the formal scanning position (X, Y). By querying the comparison table between each scanning position and the height of the upper surface of the workpiece 180 to be measured and interpolating to calculate the actual height of the surface of the workpiece 180 to be measured at the current formal scanning position, the optimal focal plane distance is superimposed to determine the target height of the focusing axis 113, and the motion stage module 110 drives the focusing axis 113 to move to the target height of the focusing axis 113, thereby realizing automatic focusing of the ultrasonic probe module 130.

[0152] When scanning according to the preset scanning trajectory, the number of pre-scanning trajectory lines of the pre-scanning operation can be reduced, and a rough comparison table of each scanning position and height of the upper surface of the workpiece to be measured can be determined. Through interpolation calculation, the corresponding table of each scanning position and height of the workpiece to be measured in the actual scanning trajectory is calculated, and a certain focal plane height control error is introduced, which can shorten the pre-scanning time and improve the overall scanning efficiency.

[0153] In a possible embodiment, the ultrasonic probe module 130 itself can also realize the ranging function. When the surface morphology of the workpiece 180 to be measured changes slightly, the ranging module 120 can be cancelled and the ultrasonic probe module 130 can be used to perform the pre-scanning operation.

[0154] Fig.17 The figure is a schematic diagram of a scanning trajectory of an ultrasonic probe module also serving as a distance measurement module in a two-round scanning mode according to an exemplary embodiment.

[0155] like Fig.17 As shown, in a possible embodiment, the automatic focusing process of the ultrasound probe module 130 also serving as the distance measurement module 120 in the two-round scanning mode is as follows:

[0156] like Fig.17 As shown in (a), first, the position of the focusing axis 113 remains fixed, and the motion stage module 110 drives the scanning axis 111 and the stepping axis 112 to move the ultrasonic probe module 130 to perform a round of pre-scanning operation, and the entire plane of the workpiece 180 to be measured is completely scanned along the S-shaped reciprocating scanning trajectory, and the actual height data of the entire plane of the workpiece 180 to be measured is recorded, and a comparison table of each scanning position and height of the upper surface of the workpiece 180 to be measured is generated.

[0157] like Fig.17As shown in (a), secondly, the motion stage module 110 drives the ultrasonic probe module 130 to perform a round of formal scanning operation along an S-shaped reciprocating scanning trajectory. During the formal scanning operation, the position coordinates of the formal scanning axis 111 and the stepping axis 112 are read in real time to determine the formal scanning position (X, Y). By querying each scanning position and height comparison table of the upper surface of the workpiece 180 to interpolate and calculate the actual height of the surface of the workpiece 180 at the current formal scanning position, the optimal focal plane spacing is superimposed to determine the target height of the focusing axis 113. The motion stage module 110 drives the focusing axis 113 to move to the target height of the focusing axis 113, thereby realizing automatic focusing of the ultrasonic probe module 130.

[0158] Fig.18 The figure is a schematic diagram of a scanning trajectory of an ultrasonic probe module also serving as a distance measurement module in a line-by-line scanning mode according to an exemplary embodiment.

[0159] like Fig.18 As shown, in a possible embodiment, the automatic focusing operation process of the ultrasound probe module 130 also serving as the ranging module 120 in the progressive scanning mode is as follows:

[0160] like Fig.18 As shown in (a), first, the position of the focusing axis 113 remains fixed, the motion stage module 110 drives the ultrasonic probe module 130 to perform a pre-scan operation on the first row, the stepping axis 112 is fixed at the position of the first row, and the scanning axis 111 is driven to move from left to right along the X-axis, and the actual height data of the surface of the workpiece 180 under test in the first row is recorded, and a comparison table between each scanning position and height of the upper surface of the workpiece 180 under test is generated.

[0161] like Fig.18 (b) shows, secondly, the motion stage module 110 drives the ultrasonic probe module 130 to perform the formal scanning operation of the first row, fixes the stepping axis 112, and drives the scanning axis 111 to move from right to left along the X-axis. During the formal scanning process, the current position of the scanning axis 111 is read in real time to determine the formal scanning position (X, Y). By querying the comparison table of each scanning position and height of the upper surface of the workpiece 180 to interpolate and calculate the actual height of the surface of the workpiece 180 at the current formal scanning position, the optimal focal plane spacing is superimposed to determine the target height of the focusing axis 113, and the motion stage module 110 drives the focusing axis 113 to move to the target height of the focusing axis 113.

[0162] like Fig.18 (c) Fig.18As shown in (d), after the pre-scan and the formal scanning operations of the first row are completed, the stepper axis 112 is moved to the starting point of the second row, and the ultrasonic probe module 130 is driven to cyclically repeat the pre-scan and the formal scanning operations until the ultrasonic scanning of the entire surface of the workpiece 180 is completed, thereby realizing automatic focusing of the ultrasonic probe module 130.

[0163] Fig.19 The figure is a schematic diagram of a scanning trajectory of an ultrasonic probe module also serving as a distance measurement module in a parallel scanning mode according to an exemplary embodiment.

[0164] like Fig.19 As shown, in a possible embodiment, the automatic focusing operation process of the ultrasound probe module 130 also serving as the ranging module 120 in the parallel scanning mode is as follows:

[0165] like Fig.19 (a) and Fig.19 As shown in (b), the motion stage module 110 drives the ultrasonic probe module 130 to perform pre-scanning and formal scanning operations along an S-shaped reciprocating scanning trajectory. When the stepping distance of the stepping axis 112 is not greater than a preset distance threshold, such as 1 mm, the scanning line of the pre-scanning operation and the scanning line of the formal scanning operation are very close in the direction of the stepping axis 112, and the position deviation between the two in the Z-axis direction is within an acceptable range. The actual height data of the current formal scanning operation can be used as the pre-scan height data of the next scanning line, thereby only using the ultrasonic probe module 130 to implement the pre-scanning and formal scanning operations.

[0166] When the step distance is greater than a preset threshold, such as 1 mm, only the ultrasonic probe module 130 is used as the distance measurement module 120, and the deviation between the pre-scan height data and the formal scan height data exceeds an acceptable range, the parallel scanning mode cannot be used.

[0167] Fig. 20 The present invention is a flow chart of an automatic focusing method of an ultrasonic scanning microscope according to an exemplary embodiment.

[0168] like Fig. 20 As shown, the present disclosure also provides an automatic focusing method for an ultrasonic scanning microscope, including S11 to S15.

[0169] S11, according to a preset scanning mode, the moving stage module is used to drive the distance measurement module to perform a pre-scanning operation to determine each scanning position and height comparison table of the upper surface of the workpiece to be measured.

[0170] The preset scanning modes may include a two-round scanning mode, a line-by-line scanning mode, and a parallel scanning mode.

[0171] Each scanning position and height comparison table of the upper surface of the workpiece to be measured includes each scanning position (X, Y) and the actual height H of the upper surface of the workpiece to be measured at the scanning position (X, Y).

[0172] S12, according to the preset scanning mode, the motion stage module is used to drive the ultrasonic probe module to perform a formal scanning operation, and the target height of the focus axis is determined according to the comparison table of each scanning position and height of the upper surface of the workpiece to be measured and the optimal focal plane spacing.

[0173] S13, sending the target height of the focus axis to the motion control system.

[0174] S14, using a motion control system to control the focus axis of the motion stage module to move to a target height of the focus axis.

[0175] S15, at the target height of the focusing axis, the ultrasonic probe module is used to detect the workpiece.

[0176] In a possible embodiment, S11 may include S21 to S23.

[0177] S21, using the motion table module to drive the distance measuring module to perform a pre-scanning operation on the upper surface of the workpiece to be measured according to the scanning trajectory corresponding to the preset scanning mode, reading the position coordinates of the scanning axis and the stepping axis, and determining the two-dimensional coordinates of each scanning position on the upper surface of the workpiece to be measured and the distance between the distance measuring module corresponding to each scanning position and the upper surface of the workpiece to be measured.

[0178] Among them, in the two-round scanning mode, the pre-scanning operation and the formal scanning operation respectively execute an S-shaped reciprocating scanning trajectory; in the line-by-line scanning mode, the pre-scanning operation is first performed on each line, and then the formal scanning operation is performed in the opposite direction of the line, and the reciprocating scanning trajectory is executed line by line; in the parallel scanning mode, the pre-scanning operation and the formal scanning operation simultaneously execute the S-shaped scanning trajectory.

[0179] The position coordinates of the scanning axis and the stepping axis are used as the two-dimensional coordinates of each scanning position on the upper surface of the workpiece to be measured, which are expressed as (X, Y). The distance between the ranging module corresponding to each scanning position and the upper surface of the workpiece to be measured is expressed as S, that is, the distance measured by the ranging module.

[0180] S22, determining the actual height of the upper surface of the workpiece to be measured corresponding to each scanning position according to the distance between the distance measuring module corresponding to each scanning position and the upper surface of the workpiece to be measured and the height of the distance measuring module.

[0181] From step S21 to step S22, the actual height of the upper surface of the workpiece to be measured corresponding to each scanning position is:

[0182] H=LS

[0183] Wherein, H represents the actual height of the scanning position (X, Y) on the upper surface of the workpiece being measured, L represents the height of the ranging module, and S represents the distance between the ranging module and the surface of the workpiece being measured.

[0184] S23, determining a comparison table of each scanning position and height of the upper surface of the measured workpiece according to the two-dimensional coordinates of each scanning position of the upper surface of the measured workpiece and the actual height of the upper surface of the measured workpiece corresponding to each scanning position.

[0185] In a possible embodiment, S12 may include S31 to S33.

[0186] S31, using the motion table module to drive the ultrasonic probe module to perform a formal scanning operation on the upper surface of the workpiece to be measured according to the scanning trajectory corresponding to the preset scanning mode, reading the position coordinates of the scanning axis and the stepping axis, and determining the two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured.

[0187] The two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured are expressed as (X, Y).

[0188] S32, determining the height corresponding to each formal scanning position on the upper surface of the workpiece to be measured according to the two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured and a comparison table between each scanning position on the upper surface of the workpiece to be measured and the height.

[0189] Among them, according to the two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured, which are expressed as (X, Y), the height H corresponding to each formal scanning position on the upper surface of the workpiece to be measured is determined in the comparison table.

[0190] S33, determining a target height of the focus axis according to the height corresponding to each formal scanning position of the upper surface of the workpiece to be measured and the optimal focal plane distance.

[0191] As an example, the height corresponding to each formal scanning position of the upper surface of the workpiece to be measured is summed with the optimal focal plane distance to determine the target height of the focus axis.

[0192] From steps S31 to S33, the target height of the focus axis is:

[0193] Z=H+F

[0194] Wherein, Z represents the target height of the focus axis, H represents the actual height H of the upper surface of the workpiece to be measured corresponding to the current position (X, Y), and F represents the optimal focal plane distance.

[0195] The automatic focusing device and the automatic focusing method of the ultrasonic scanning microscope provided by the present invention realize automatic focusing during the scanning process of non-flat workpieces such as tilted, warped, and arched, and improve the quality of the scanned image by combining pre-scanning and formal scanning.

[0196] The above describes the specific embodiments of the present disclosure. It should be understood that the present disclosure is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present disclosure. The above preferred features can be used in any combination without conflicting with each other.

Claims

1. An automatic focusing device for an ultrasonic scanning microscope, characterized in that: include: Motion table module, distance measurement module, ultrasound probe module; The motion stage module includes a scanning axis, a focusing axis and a stepping axis, wherein the scanning axis is arranged along the X-axis direction, the stepping axis is arranged along the Y-axis direction, the focusing axis is arranged along the Z-axis direction, the scanning axis is perpendicular to the stepping axis and arranged on the stepping axis, the focusing axis is perpendicular to the scanning axis and arranged on the scanning axis, and the motion stage module is used to adjust the positions of the ranging module and the ultrasound probe module and focus the ultrasound module probe; The distance measuring module is installed on the scanning axis or the focusing axis, and the distance measuring module is used to measure the surface height of the workpiece being measured; The ultrasonic probe module is mounted on the focusing axis, the ultrasonic probe module and the distance measuring module are arranged in parallel with each other, and the ultrasonic probe module is used to transmit and receive ultrasonic waves to detect the workpiece to be measured.

2. The automatic focusing device for ultrasonic scanning microscope according to claim 1, characterized in that: The scanning axis, the focusing axis, the ranging module and the ultrasonic probe module move along the Y-axis direction on the stepping axis; The focusing axis, the ranging module and the ultrasonic probe module move along the X-axis direction on the scanning axis; If the distance measuring module is installed on the focusing axis, the distance measuring module moves along the Z-axis direction on the focusing axis; The ultrasonic probe module moves along the Z-axis direction on the focusing axis.

3. The automatic focusing device for ultrasonic scanning microscope according to claim 1, characterized in that: It also includes a first connecting plate and a second connecting plate, the focusing axis is fixed to the scanning axis through the first connecting plate, the ultrasonic probe module is fixed to the second connecting plate, and the ultrasonic probe module is installed on the focusing axis through the second connecting plate.

4. The automatic focusing device for ultrasonic scanning microscope according to claim 3, characterized in that: It also includes a third connecting plate, the distance measuring module is fixed on the third connecting plate, and the distance measuring module and the third connecting plate are installed on the scanning axis through the first connecting plate.

5. The automatic focusing device for ultrasonic scanning microscope according to claim 1, characterized in that: It also includes a water tank module, which is arranged at the bottom of the motion platform module and is used to place the workpiece to be measured.

6. An automatic focusing method for an ultrasonic scanning microscope, characterized in that: include: According to the preset scanning mode, the motion stage module is used to drive the distance measurement module to perform a pre-scanning operation to determine each scanning position and height comparison table of the upper surface of the workpiece to be measured; According to the preset scanning mode, the motion stage module is used to drive the ultrasonic probe module to perform a formal scanning operation, and the target height of the focus axis is determined according to a comparison table of each scanning position and height of the upper surface of the workpiece to be measured and an optimal focal plane spacing; sending the target height of the focus axis to a motion control system; Using the motion control system to control the focus axis of the motion stage module to move to a target height of the focus axis; At the target height of the focusing axis, the ultrasonic probe module is used to detect the workpiece.

7. The method according to claim 6, characterized in that The preset scanning modes include: a two-round scanning mode, a line-by-line scanning mode and a parallel scanning mode.

8. The method according to claim 6, characterized in that According to the preset scanning mode, the motion stage module is used to drive the distance measurement module to perform a pre-scanning operation to determine each scanning position and height comparison table of the upper surface of the workpiece to be measured, including: The moving stage module is used to drive the distance measuring module to perform the pre-scanning operation on the upper surface of the workpiece to be measured according to the scanning trajectory corresponding to the preset scanning mode, read the position coordinates of the scanning axis and the stepping axis, and determine the two-dimensional coordinates of each scanning position on the upper surface of the workpiece to be measured and the distance between the distance measuring module and the upper surface of the workpiece to be measured corresponding to each scanning position; Determine the actual height of the upper surface of the workpiece to be measured corresponding to each scanning position according to the distance between the distance measuring module corresponding to each scanning position and the upper surface of the workpiece to be measured and the height of the distance measuring module; According to the two-dimensional coordinates of each scanning position on the upper surface of the workpiece to be measured and the actual height of the upper surface of the workpiece to be measured corresponding to each scanning position, a comparison table of each scanning position and height of the upper surface of the workpiece to be measured is determined.

9. The method according to claim 6, characterized in that According to the preset scanning mode, the motion stage module is used to drive the ultrasonic probe module to perform a formal scanning operation, and the target height of the focus axis is determined according to a comparison table of each scanning position and height of the upper surface of the workpiece to be measured and an optimal focal plane spacing, including: The motion stage module is used to drive the ultrasonic probe module to perform the formal scanning operation on the upper surface of the workpiece to be measured according to the scanning trajectory corresponding to the preset scanning mode, read the position coordinates of the scanning axis and the stepping axis, and determine the two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured; Determine the height corresponding to each formal scanning position on the upper surface of the workpiece to be measured according to the two-dimensional coordinates of each formal scanning position on the upper surface of the workpiece to be measured and the comparison table between each scanning position and height on the upper surface of the workpiece to be measured; The target height of the focus axis is determined according to the height corresponding to each formal scanning position of the upper surface of the workpiece to be measured and the optimal focal plane distance.

10. The method according to claim 9, characterized in that Determining the target height of the focus axis according to the height corresponding to each formal scanning position on the upper surface of the workpiece to be measured and the optimal focal plane distance includes: The height corresponding to each formal scanning position on the upper surface of the workpiece to be measured is summed with the optimal focal plane distance to determine the target height of the focus axis.

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