TWI735337B - Linear displacement calibration method and inspection apparatus using the same - Google Patents

Abstract

A linear displacement calibration method includes the following steps: measuring the displacement of a moving member in a linear direction through a displacement sensor to obtain a plurality of first measuring distances, measuring the displacement of the moving member in the linear direction through a calibration measuring device to obtain a plurality of second measuring distances, establishing a relative relationship comparison table based on the first measuring distances and the second measuring distances, so that the first measuring distances correspond to the second measuring distances respectively, and obtaining the second measuring distance corresponding to each of the first measuring distances from the relative relationship comparison table as a calibration distance. Therefore, the speed and the efficiency of calibration can be improved. The present disclosure also provides an inspection apparatus using the above-mentioned linear displacement calibration method.

Description

Linear displacement correction method and detection equipment using the method

The invention relates to a linear displacement correction method, in particular to a linear displacement correction method for correcting the magnitude of the linear displacement of a moving part and a detection device using the method.

The existing optical inspection equipment drives a stage to move linearly through a driving mechanism, so that the stage can drive an object under test carried by the stage to pass an optical camera for the optical camera to capture an image of the object under test. The optical inspection equipment also reads the scale of an optical ruler through a reading head of a linear encoder and feeds it back to a controller, so that the controller controls the driving mechanism to drive the moving speed and stroke of the stage according to the scale.

However, the assembly tolerance between the detailed components of the drive mechanism, the assembly tolerance between the drive mechanism and the stage, the assembly tolerance between the pickup head and the optical scale, or the tolerance between multiple scales of the optical scale, etc. It will affect the accuracy of the linear encoder to measure the moving distance of the stage, making the controller drive the stage to move too slow or If the speed is too fast, the image of the object to be measured captured by the optical camera will be deformed. When the subsequent stitching is to be carried out, the image will be distorted or even unable to be stitched.

Therefore, one of the objectives of the present invention is to provide a linear displacement correction method that can overcome at least one of the disadvantages of the prior art.

Therefore, the linear displacement correction method of the present invention includes the following steps in some implementations: measuring the displacement of a moving part along a straight line through a displacement sensor to obtain a plurality of first measurement distances, and A calibration measuring device measures the displacement of the moving part along the linear direction to obtain a plurality of second measurement distances; establishes a relative relationship comparison table according to the first measurement distance and the second measurement distance, so that the first measurement The measured distances respectively correspond to the second measured distances; and the second measured distances corresponding to the first measured distances are obtained from the relative relationship comparison table as a corrected distance.

Therefore, the linear displacement correction method of the present invention in other embodiments includes the following steps: driving a moving part to move in a straight direction through a driving mechanism; and measuring the movement of the moving part in a straight direction through a displacement sensor. Displacement, the displacement of the moving part in the linear direction is measured by a calibration measuring device, the electronic signal fed back by the displacement sensor is received by an arithmetic processing module to calculate a plurality of first measurement distances, and the calibration is received The electronic signal fed back by the measuring device is used to calculate a plurality of second measurement distances; the calculation processing module establishes a phase according to the first measurement distance and the second measurement distance The relationship comparison table makes the first measurement distance correspond to the second measurement distance respectively; and the arithmetic processing module obtains the second measurement distance corresponding to each first measurement distance from the relative relationship comparison table as a Correct the distance.

Another object of the present invention is to provide a detection device that can overcome at least one of the disadvantages of the prior art.

Therefore, in some embodiments, the detection device of the present invention includes a moving part, a driving mechanism, a displacement sensor, a calibration measurement device, and an arithmetic processing module. The driving mechanism is used to drive the moving part to move along a straight line. The displacement sensor is used to measure the displacement of the moving part along the linear direction. The calibration measuring device is used to measure the displacement of the moving part along the linear direction. The arithmetic processing module is electrically connected to the displacement sensor and the calibration measurement device. The arithmetic processing module is used to receive electronic signals fed back by the displacement sensor to calculate a plurality of first measurement distances, and to receive the calibration The electronic signals fed back by the measuring device are used to calculate a plurality of second measurement distances, and the calculation processing module establishes a relative relationship comparison table according to the first measurement distance and the second measurement distance.

The present invention has at least the following effects: the displacement of the moving part along the linear direction is measured by the calibration measurement device to obtain the second measurement distance, so that the arithmetic processing module can establish the first measurement distance and the second measurement The relative relationship of the measuring distance is compared with the table, and the linear displacement correction is performed by the look-up table method in the actual optical inspection, so as to improve the speed and efficiency of the correction. By inputting the second measured distance as the correction distance to the image processing module as a calculation parameter, the image processing module can combine the regional images. Connect as a complete image without distortion. Assemble the calibration and measurement device on the machine, moving parts and the ground, without adjusting or changing the related structure of the testing equipment, the testing equipment can be adjusted to improve the convenience of assembly and use. The detection device does not need to use a high-end and expensive encoder to achieve the effect of linear displacement correction, therefore, the manufacturing cost of the detection device can be reduced.

100: testing equipment

1: Machine

11: Top surface

12: Rail

13: front end

14: backend

2: Moving parts

3: drive mechanism

31: Motor

32: Screw

33: Coupling

4: Image capture device

5: Displacement sensor

51: Optical ruler

52: read head

6: Calibration measuring device

61: Correction beam transceiver module

611: Bracket

612: Correction beam transceiver head

62: The first optical module

621: The first magnetic metal sheet

622: The first magnetic frame

623: Spectroscope

624: first mirror

63: The second optical module

631: second magnetic metal sheet

632: second magnetic frame

633: second mirror

7: Operation processing module

71: Relative relationship comparison table

711: The first measurement distance field

712: The second measurement distance field

8: Image processing module

9: Ground

D: straight line direction

S1~S4: Calibration steps

The other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: FIG. 1 is a flow chart of a calibration step of the first embodiment of the linear displacement calibration method of the present invention; FIG. 2 is the use of the first embodiment A top view of a detection device of an embodiment; FIG. 3 is a side view of the detection device using the first embodiment; FIG. 4 is a block diagram of a connection relationship of the detection device using the first embodiment; Another top view of the detection device of an embodiment; FIG. 6 is a relative relationship comparison table established using the first embodiment; FIG. 7 is a top view of the detection device using the second embodiment of the linear displacement correction method of the present invention; And Fig. 8 is a side view of the detection device using the second embodiment.

1 and 2, the first embodiment of the linear displacement correction method of the present invention includes the following correction steps. Step S1: driving the moving part to move, step S2: measuring the displacement of the moving part, step S3: establishing a comparison table, and step S4: obtaining a correction distance. The linear displacement correction method is used to correct the linear displacement of a detection device 100. In the first embodiment of this case, the detection device 100 is an optical detection device as an example. The detection device 100 can also be any other device that needs to correct linear displacement. Not limited to the use of optical detection.

Referring to Figure 2, Figure 3 and Figure 4, in the first embodiment of the present case, the detection equipment 100 includes a machine 1, a moving part 2, a driving mechanism 3, an image capturing device 4, a displacement sensor 5 , A calibration measurement device 6, an arithmetic processing module 7 and an image processing module 8. The machine 1 includes a top surface 11, a guide rail 12 disposed on the top surface 11, a front end 13, and a rear end 14 opposite to the front end 13. The guide rail 12 extends along a linear direction D from front to back. The moving part 2 is an example of a stage for carrying an object to be measured (not shown), which is slidably connected to the guide rail 12 and can be operated to move along the linear direction D. The driving mechanism 3 includes a motor 31, a screw 32 and a coupling 33. The motor 31 is installed on the top surface 11 of the machine table 1. The screw 32 is connected to the motor 31 and can be driven to rotate. The screw 32 extends along the linear direction D and is located on the side of the guide rail 12. The coupling 33 is arranged on one side of the moving part 2 and is screwed to the screw 32. Thereby, when the motor 31 drives the screw 32 to rotate, the screw 32 can drive the moving part 2 to move on the guide rail 12 through the coupling 33.

In the first embodiment of the present case, the image capturing device 4 is a line-scan camera (Line-Scan Camera) as an example, but it is not limited to this. It is set above the guide rail 12 of the machine 1 to capture the The image of the object to be measured moved by the moving part 2. The displacement sensor 5 is a linear encoder as an example, but not limited to this, and is used to measure the displacement of the moving part 2 along the linear direction D. The displacement sensor 5 includes an optical ruler 51 and a reading head 52. The optical ruler 51 is arranged on the top surface 11 of the machine 1 and is located on the side of the guide rail 12 opposite to the screw 32. The reading head 52 is arranged on the side of the moving part 2 opposite to the coupling 33 and above the optical scale 51, and the reading head 52 is used to read the corresponding scales of the multiple scales (not shown) of the optical scale 51. In order to convert it into the corresponding electronic signal. In other implementations of the first embodiment of the present invention, the position of the displacement sensor 5 relative to other components is not limited to the above, and can be changed according to design requirements.

In the first embodiment of the present case, the calibration and measurement device 6 is a laser interferometer as an example, but not limited to this, it is used to measure the displacement of the moving part 2 along the linear direction D. The calibration measurement device 6 includes a calibration beam transceiver module 61, a first optical module 62 and a second optical module 63. The corrected beam transceiver module 61 includes a bracket 611 and a corrected beam transceiver head 612. The bracket 611 is an example of a tripod for supporting on a ground 9, but is not limited to this. The bracket 611 is separated from the front end 13 of the machine 1 by an appropriate distance. The correction beam transceiver head 612 is arranged on the bracket 611 to transmit and receive the correction beam such as a laser. The first optical module 62 includes a first magnetic metal sheet 621, a first magnetic frame 622, a beam splitter 623 and a first reflection mirror 624. First The magnetic metal sheet 621 is fastened to the top surface 11 of the machine 1 and adjacent to the front end 13 by screws, for example. The first magnetic frame 622 is magnetically attracted to the first magnetic metal sheet 621 to be fixed thereon. The beam splitter 623 is disposed on one side of the first magnetic frame 622 and adjacent to the top end thereof. The beam splitter 623 is aligned behind the correction beam transceiver head 612 for dividing the correction beam emitted by the correction beam transceiver head 612 into two correction beams. The first reflector 624 is arranged on one side of the beam splitter 623, and the beam splitter 623 is located between the first magnetic frame 622 and the first reflective mirror 624. The first reflective mirror 624 is used to separate the beam splitter 623. A beam of correction light is reflected back to the beam splitter 623.

The second optical module 63 includes a second magnetically permeable metal sheet 631, a second magnetic frame 632, and a second reflector 633. The second magnetic metal sheet 631 is fastened to the top surface of the moving part 2 by, for example, screws. The second magnetic frame 632 is attracted to the second magnetic metal sheet 631 through magnetic force to be fixed thereon. The second reflector 633 is arranged on the front side of the second magnetic frame 632 and is adjacent to the top end thereof, and is aligned behind the beam splitter 623, so that the correction beam transceiver head 612, the beam splitter 623 and the second reflector 633 are arranged at intervals along the linear direction D . The second reflecting mirror 633 is used to reflect another beam of correction light split by the beam splitter 623 back to the beam splitter 623. The correction beam transceiver head 612 is used for receiving the correction beam reflected to the beam splitter 623 and passing through the beam splitter 623 to convert it into a corresponding electronic signal.

It is worth noting that, in the first embodiment of the present case, the first optical module 62 and the second optical module 63 are respectively fixed to the machine table 1 and the moving part 2 by magnetic attraction. In other embodiments, the first optical module 62 and the second optical module 63 are An optical module 62 and a second optical module 63 It can be fixed on the machine 1 and the moving part 2 in other ways, and is not limited to the aforementioned magnetic attraction method.

The arithmetic processing module 7 is electrically connected to the reading head 52 of the displacement sensor 5 and the calibration beam transceiver head 612 of the calibration measurement device 6. The arithmetic processing module 7 is used to receive the electronic signal fed back from the reading head 52 and the electronic signal fed back from the correction beam transceiver head 612. The image processing module 8 is electrically connected to the image capturing device 4 and the arithmetic processing module 7 for receiving multiple area images of the object to be measured captured by the image capturing device 4 to stitch them into a complete image .

The following is a detailed description of the operation of the detection device 100 using the linear displacement correction method of the first embodiment of the present invention: Referring to Figures 1, 2 and 5, in step S1, the motor 31 of the drive mechanism 3 drives the screw 32 to rotate, so that The screw 32 drives the moving part 2 through the coupling 33 to move from an initial position (as shown in FIG. 2) to a critical position (as shown in FIG. 5) along the linear direction D.

Referring to FIGS. 1, 4 and 5, step S2 is performed during the movement of the moving part 2, and the displacement of the moving part 2 along the linear direction D is measured through the displacement sensor 5. The reading head 52 reads the corresponding scale of the optical scale 51 to convert it into a corresponding electronic signal, and the electronic signal is fed back to the arithmetic processing module 7. At the same time, the displacement of the moving part 2 along the linear direction D is measured through the correction measuring device 6. The correction beam emitted by the correction beam transceiver head 612 passes through the beam splitter 623 and is divided into two correction beams. The correction beams are respectively The fixed first mirror 624 and the moving second mirror 633 reflect back and meet on the beam splitter 623 to generate interference fringes. When the second mirror 633 moves, the correction beam transceiver head 612 converts the light intensity change of the interference fringe into an electronic signal and feeds it back to the arithmetic processing module 7. The arithmetic processing module 7 receives the electronic signal fed back from the reading head 52 to calculate a corresponding first measured distance, and receives the electronic signal fed back from the correction beam transceiver head 612 to calculate a corresponding second measured distance.

During the movement of the moving part 2, the image capturing device 4 sequentially captures multiple regional images of the object to be tested and feeds them back to the image processing module 8. When the moving part 2 moves to the critical position, the driving mechanism 3 stops driving the moving part 2 to move. In the process of moving the moving part 2 from the initial position to the critical position, the arithmetic processing module 7 calculates a plurality of first measurement distances d1~dn (as shown in FIG. 6) by using the electronic signal fed back from the reading head 52 And by calibrating the electronic signals fed back from the beam transceiver head 612, a plurality of second measurement distances D1 to Dn (as shown in FIG. 6) are calculated.

Refer to Figure 1, Figure 4 and Figure 6, followed by step S3, the arithmetic processing module 7 establishes a relative relationship comparison table 71 according to the first measured distance d1~dn and the second measured distance D1~Dn, the relative relationship comparison table 71 has a first measurement distance field 711 and a second measurement distance field 712. The first measurement distance field 711 is used to display the first measurement distance d1~dn, and the second measurement distance field 712 is used to display the second measurement distance D1~Dn. In this way, the first measurement distances d1 to dn correspond to the second measurement distances D1 to Dn, respectively. After the relative relationship comparison table 71 is established, the arithmetic processing module 7 stores Save the relative relationship comparison table 71.

In step S4, the arithmetic processing module 7 obtains the second measurement distance D1~Dn corresponding to each first measurement distance d1~dn from the relative relationship comparison table 71, for example, using a table lookup method. For example, when the first measurement distance obtained by the arithmetic processing module 7 is d2, the corresponding second measurement distance is obtained by using the look-up table method as D2, and the second measurement distance D2 is used as a correction distance, which is a Used to input the operation parameters to the image processing module 8. The calculation processing module 7 obtains the correction distance by the look-up table method, which can reduce the calculation time and load, so as to improve the speed and efficiency of the correction.

Since the image processing module 8 splices the regional images captured by the image capturing device 4, the relative position and distance between the regional images are important factors that affect whether the complete image after splicing is distorted. The second measured distance D1~Dn corresponding to the corrected distance is input to the image processing module 8 as a calculation parameter, so that the relative position and distance between the regional images will not be affected by the measurement accuracy of the displacement sensor 5. Therefore, the image processing module 8 can stitch the regional images into a complete image without distortion.

Referring to FIGS. 7 and 8, the step flow of the second embodiment of the linear displacement correction method of the present invention is substantially the same as that of the first embodiment, and the difference lies in the assembly method of the correction measurement device 6.

In the second embodiment of the present case, the first magnetic metal sheet 621 of the first optical module 62 is fastened to the top surface of the moving part 2 through screws, so that the first optical module 62 is installed On the moving part 2. The second magnetic metal sheet 631 of the second optical module 63 is fastened to the top surface 11 of the machine table 1 through screws and is adjacent to the rear end 14, so that the second optical module 63 is disposed on the machine table 1. Thereby, the first optical module 62 can be driven by the moving part 2 to move relative to the corrected beam transceiver module 61 and the second optical module 63.

In summary, in the linear displacement correction method of each embodiment, the displacement of the moving part 2 along the linear direction D is measured by the correction measuring device 6 to obtain the second measured distance D1~Dn, so that the calculation process The module 7 can establish a relative relationship comparison table 71 and use the look-up method to obtain the second measurement distance D1~Dn corresponding to each first measurement distance d1~dn, and use it as the correction distance. In this way, the speed and efficiency of calibration can be improved. By inputting the corresponding second measured distances D1 to Dn as the correction distances to the image processing module 8 as calculation parameters, the image processing module 8 can stitch the regional images into a complete image without distortion. In addition, the calibration and measurement device 6 is assembled on the machine table 1, the moving part 2 and the ground 9, without adjusting or changing the related components of the detection device 100, so that the detection device 100 can perform linear displacement calibration. Therefore, the convenience of assembly and use can be improved. Furthermore, the detection device 100 does not need to use a high-end and expensive encoder to achieve the effect of linear displacement correction. Therefore, the manufacturing cost of the detection device 100 can be reduced, and the purpose of the invention can indeed be achieved.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the patent specification still belong to The scope covered by the invention patent 内内。 In the enclosure.

S1~S4: Calibration steps

Claims (13)

A linear displacement correction method includes the following steps: measuring the displacement of a moving part along a straight line through a displacement sensor to obtain a plurality of first measurement distances; measuring the moving part through a correction measuring device The displacement moving along the straight line direction to obtain a plurality of second measurement distances; according to the first measurement distances and the second measurement distances to establish a relative relationship comparison table, so that the first measurement distances Respectively corresponding to the second measured distances; and the second measured distance corresponding to each of the first measured distances is obtained from the relative relationship comparison table as a corrected distance. The linear displacement correction method according to claim 1, wherein the correction measurement device includes a laser interferometer. The linear displacement correction method according to claim 1 or 2, wherein the second measurement distance corresponding to each first measurement distance is obtained from the relative relationship comparison table using a look-up table method. A linear displacement correction method includes the following steps: drive a moving part to move along a straight line through a driving mechanism; measure the displacement of the moving part along the straight line through a displacement sensor, and measure through a calibration measuring device Measure the displacement of the moving part along the linear direction, receive the electronic signal fed back from the displacement sensor by an arithmetic processing module to calculate a plurality of first measurement distances, and receive the feedback from the calibration measurement device Electronic signal to calculate multiple second measurement distances; The arithmetic processing module establishes a relative relationship comparison table based on the first measurement distances and the second measurement distances, so that the first measurement distances correspond to the second measurement distances respectively; and The arithmetic processing module obtains the second measured distance corresponding to each of the first measured distances from the relative relationship comparison table as a corrected distance. The linear displacement correction method according to claim 4, wherein the correction measurement device includes a laser interferometer. The linear displacement correction method according to claim 4, wherein the displacement sensor includes a linear encoder. The linear displacement correction method according to any one of claims 4 to 6, wherein the arithmetic processing module uses a table look-up method to obtain the second corresponding to each of the first measured distances from the relative relationship comparison table. Measure the distance. A detection device comprising: a moving part; a driving mechanism for driving the moving part to move along a straight line; a displacement sensor for measuring the displacement of the moving part along the straight line; a calibration measurement A device for measuring the displacement of the moving part along the linear direction; and an arithmetic processing module electrically connected to the displacement sensor and the calibration measuring device, the arithmetic processing module for receiving the displacement The electronic signal fed back by the sensor is used to calculate a plurality of first measurement distances, and the electronic signal is used to receive the electronic signal fed back from the calibration measuring device to calculate a plurality of The second measurement distance; wherein the arithmetic processing module establishes a relative relationship comparison table based on the first measurement distance and the second measurement distance. The detection device according to claim 8, wherein the displacement sensor includes a linear encoder. The detection device according to claim 8, wherein the calibration measurement device includes a laser interferometer. The detection device according to claim 10, wherein the calibration measurement device includes a calibration beam transceiver module, a first optical module, and a second optical module arranged at intervals along the straight line direction, the second optical module The optical module is arranged on the moving part and can be driven by it to move relative to the corrected beam transceiver module and the first optical module. The detection device according to claim 10, wherein the calibration measurement device includes a calibration beam transceiver module, a first optical module, and a second optical module arranged at intervals along the linear direction, the first The optical module is arranged on the moving part and can be driven by it to move relative to the corrected beam transceiver module and the second optical module. The detection device according to any one of claims 8 to 12, further comprising an image processing module electrically connected to the arithmetic processing module, the arithmetic processing module can use a look-up method to compare the relative relationship table The second measured distance corresponding to each of the first measured distances is obtained as an operation parameter for input to the image processing module.

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