A high-precision thickness measurement method and device for large-size objects

Abstract

The present application relates to a kind of high-precision thickness measurement method and device for large size object, the method includes using two groups of point laser source respectively towards the upper and lower surface of the measured object first laser, oblique second laser, and then obtain the first coordinate of the corresponding reflection point of first laser on the measured object, the second coordinate of the corresponding reflection point of second laser on the measured object, and the included angle θ of first laser and horizontal plane, and then calculate the horizontal offset ΔA of first coordinate and preset origin, and the horizontal offset ΔB of second coordinate and preset origin, i.e. the thickness H of measured object = | ΔA- ΔB | * tag (θ), the present application is suitable for the center point thickness measurement of large plane or super large plane, suitable for a variety of shapes of object, thickness detection will not be disturbed by slight warping, without setting relative test reference.

Description

TECHNICAL FIELD

[0001] The present application relates to the thickness detection technical field, more particularly, to a high-precision thickness measurement method and device for large-size objects. BACKGROUND

[0002] When producing 5G supporting products, it is often necessary to process a stepped groove on a steel sheet with a size of more than 500mmx400mm and a thickness of 0.12mm-0.15mm, and the depth of the stepped groove is the height of the tin paste printing, that is, the processing quality of the stepped groove will directly affect the printing quality. Therefore, how to accurately measure the thickness of the steel sheet is extremely critical during processing. The current common methods are as follows:

[0003] Firstly, a large micrometer is used for measurement. This method needs to customize a gauge, and the larger the size of the measured object, the higher the price of the gauge. Moreover, it is not convenient to place the measured object, and the measured size is not accurate.

[0004] Secondly, a marble platform is used. This method is suitable for the case where the steel sheet has a stepped groove on only one side, but not suitable for the case where the steel sheet has a stepped groove on both sides. In addition, the extrusion of the probe will cause the steel mesh to warp, so that the measured thickness data is not accurate.

[0005] Thirdly, a side projection measurement method is used. This method requires that the steel sheet must have an opening, otherwise it cannot be measured.

[0006] Therefore, it is still necessary to improve the existing thickness measurement method to solve the above problems. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a high-precision thickness measurement method and device for large-size objects to solve the above-mentioned defects of the prior art.

[0008] The technical scheme adopted by the present application to solve the technical problem is:

[0009] On the one hand, a high-precision thickness measurement method for large-size objects is provided, which comprises the following steps:

[0010] Two groups of point laser sources emit oblique first laser and oblique second laser towards the upper and lower surfaces of the measured object respectively; wherein the measured object is not a transparent object, and the two groups of point laser sources are coaxial;

[0011] The first coordinate of the corresponding reflection point of the first laser on the measured object, the second coordinate of the corresponding reflection point of the second laser on the measured object, and the included angle θ between the first laser and the horizontal plane are obtained;

[0012] Calculate the horizontal offset △A of the first coordinate from the preset origin, and the horizontal offset △B of the second coordinate from the preset origin;

[0013] The thickness H of the measured object is |△A-△B|*tag(θ).

[0014] Preferably, the step of obtaining coordinates comprises:

[0015] Two sets of cameras are used to obtain a first image of the first laser corresponding to the reflection point on the measured object, and a second image of the second laser corresponding to the reflection point on the measured object; wherein the lenses of the two sets of cameras are directly opposite, the two sets of cameras are vertically placed, and the height of the overlapping part of the depth of field of the two sets of cameras is not less than the initial thickness of the measured object before processing.

[0016] According to the first image and the second image, the first coordinate and the second coordinate are obtained respectively.

[0017] On the other hand, a high-precision thickness measurement device for large-size objects is provided, based on the above-mentioned high-precision thickness measurement method for large-size objects, wherein the device comprises:

[0018] Two sets of coaxial point laser sources during measurement; the two sets of point laser sources respectively emit oblique first laser and oblique second laser towards the upper and lower surfaces of the measured object; and

[0019] Two sets of cameras with lenses directly opposite and vertically placed during measurement; the two sets of cameras respectively obtain a first image of the first laser corresponding to the reflection point on the measured object, and a second image of the second laser corresponding to the reflection point on the measured object, and also respectively obtain a first coordinate of the first laser corresponding to the reflection point on the measured object, and a second coordinate of the second laser corresponding to the reflection point on the measured object; the height of the overlapping part of the depth of field of the two sets of cameras is not less than the initial thickness of the measured object before processing; and

[0020] A mounting bracket for mounting the two sets of point laser sources and the two sets of cameras.

[0021] Preferably, the device further comprises two sets of polarized light sheets corresponding one-to-one to the two sets of point laser sources.

[0022] Preferably, the device further comprises a partition plate for preventing the two sets of point laser sources from being opposite during debugging.

[0023] Preferably, one set of the point laser sources and one set of the cameras form a set of units; the mounting bracket comprises a main bracket body; the upper and lower sides of the main bracket body are both slidingly connected with a first movable seat moving along the Y axis; the first movable seat is slidingly connected with a second movable seat moving along the X axis; the two sets of units are respectively installed on the two sets of second movable seats.

[0024] The beneficial effects of the present application are:

[0025] The method is suitable for measuring the thickness of large or super large planar objects. When measuring, the irradiation position of the point laser source is changed, so that the thickness of different positions of the measured object can be detected. Unlike the previous micrometer detection, the point laser source does not need to have actual contact with the measured object. Therefore, the increase in the size of the measured object does not cause inconvenience to the movement or irradiation of the point laser source, and does not significantly increase the detection cost.

[0026] The method is suitable for measuring objects of various shapes. When measuring, the upper and lower surfaces of the measured object are detected at the same time, and the relative height of the upper and lower surfaces is obtained. Therefore, the method is suitable for measuring the thickness of measured objects that have not been opened, measured objects that have only a single stepped groove, and measured objects that have stepped grooves on both surfaces, and has good applicability.

[0027] The thickness detection is not disturbed by slight warping. An arc can be regarded as being composed of multiple straight lines. The present method is based on trigonometric functions to calculate the thickness. Therefore, slight warping at the detected position does not disturb the accuracy of the thickness detection.

[0028] There is no need to set a relative test reference. When measuring, the two groups of point laser sources form oblique directional projections in two directions. The straight line formed by the two groups of point laser sources obliquely penetrates the measured object. The two reflection points are necessarily non-coincident, so there is a lateral offset. There is no need to intentionally set a relative test reference, and the measurement is more convenient. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the present application will be further described below with reference to the drawings and embodiments. The drawings in the following description are only some embodiments of the present application. Those skilled in the art can obtain other drawings according to these drawings without creating any inventive labor:

[0030] Figure 1 is a flowchart of the implementation of a high-precision thickness measurement method for large-size objects provided by Embodiment One of the present application;

[0031] Figure 2 is a use schematic diagram of a high-precision thickness measurement method for large-size objects provided by Embodiment One of the present application (no measured object at this time);

[0032] Figure 3 is a use schematic diagram of a high-precision thickness measurement method for large-size objects provided by Embodiment One of the present application (the measured object is not slotted, and the upper and lower two boxes respectively represent images captured by the upper and lower two groups of cameras);

[0033] Figure 4is a use schematic diagram of a high-precision thickness measurement method for large-size objects provided by embodiment one of the present application (only the upper surface of the measured object is slotted, and the upper and lower two boxes are the images captured by the upper and lower two groups of cameras respectively);

[0034] Figure 5 is a use schematic diagram of a high-precision thickness measurement method for large-size objects provided by embodiment one of the present application (both the upper and lower surfaces of the measured object are slotted, and the upper and lower two boxes are the images captured by the upper and lower two groups of cameras respectively); and

[0035] Figure 6 is a structural schematic diagram of a high-precision thickness measurement device for large-size objects provided by embodiment two of the present application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the following will combine the technical scheme in the embodiments of the present application to make a clear and complete description, obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0037] Embodiment one

[0038] The embodiments of the present application provide a high-precision thickness measurement method for large-size objects, as shown in Figure 1 The method comprises the following steps:

[0039] Step S1: two groups of point laser sources are used to respectively emit oblique first laser and oblique second laser towards the upper and lower surfaces of the measured object; wherein the measured object is not a transparent object, and the two groups of point laser sources are coaxial.

[0040] Step S2: the first coordinate of the corresponding reflection point of the first laser on the measured object, the second coordinate of the corresponding reflection point of the second laser on the measured object, and the included angle θ between the first laser and the horizontal plane are obtained.

[0041] The coordinate is obtained in detail as follows:

[0042] Two groups of cameras are used to respectively obtain the first image of the corresponding reflection point of the first laser on the measured object and the second image of the corresponding reflection point of the second laser on the measured object; wherein the lenses of the two groups of cameras are directly opposite, the two groups of cameras are both placed vertically, and the height of the depth of field overlap part of the two groups of cameras is not less than the initial thickness of the measured object before processing.

[0043] The first coordinate and the second coordinate are obtained according to the first image and the second image respectively.

[0044] Wherein, the camera has sufficient depth of field, which ensures that the laser reflection point can be observed correctly with little distortion within the warping range, and the thickness of less than the depth of field range can be measured accurately within the field of view range, and is not affected by the warping of the measured object or the position relationship with the measured object.

[0045] Step S3: calculating the horizontal offset amount of the first coordinate from the preset origin, and the horizontal offset amount of the second coordinate from the preset origin.

[0046] Step S4: the thickness H of the measured object = |△A-△B|*tag(θ).

[0047] The measurement method provided by the embodiment has the following advantages:

[0048] It is suitable for center point thickness measurement of large or super large planes. During measurement, the irradiation position of the point laser source is changed, so that the thickness of different positions of the measured object can be detected. Unlike the previous micrometer detection, the point laser source does not need to have actual contact with the measured object. Therefore, the increase of the size of the measured object does not cause inconvenience to the movement or irradiation of the point laser source, and does not significantly increase the detection cost.

[0049] It is suitable for objects of various shapes. Figures 2-5 As shown in the figure, the upper and lower surfaces of the measured object are detected at the same time during measurement, and the relative height of the upper and lower surfaces is obtained. Therefore, it is suitable for thickness detection of measured objects that have not been opened, measured objects with only a single stepped groove, and measured objects with stepped grooves on both sides, and has good applicability.

[0050] The thickness detection is not disturbed by slight warping. The arc can be regarded as composed of multiple straight lines, and the method is based on trigonometric function for thickness calculation. Therefore, slight warping at the detection position does not disturb the accuracy of the thickness detection.

[0051] There is no need to set a relative test reference. During measurement, the two groups of point laser sources form oblique direction projections in two directions, and the straight line connected by the two groups of point laser sources obliquely penetrates the measured object. The two reflection points are necessarily not coincident, so there is necessarily a lateral offset, and there is no need to intentionally set a relative test reference, so the measurement is more convenient.

[0052] Embodiment two

[0053] The embodiment of the application provides a high-precision thickness measurement device for large-size objects, based on the high-precision thickness measurement method for large-size objects provided in embodiment one, as shown in the figure, the device comprises: Figure 6

[0054] ​The two groups of point laser sources 10 are coaxial during measurement; the two groups of point laser sources 10 respectively emit the first laser and the second laser obliquely towards the upper and lower surfaces of the measured object; and

[0055] The two groups of cameras 11 are vertically upright and face the lens during measurement; the two groups of cameras 11 respectively acquire the first image of the corresponding reflection point of the first laser on the measured object and the second image of the corresponding reflection point of the second laser on the measured object, and also respectively acquire the first coordinate of the corresponding reflection point of the first laser on the measured object and the second coordinate of the corresponding reflection point of the second laser on the measured object; the height of the overlapping part of the depth of field of the two groups of cameras is not less than the initial thickness of the measured object before processing; and

[0056] The mounting rack 12 is used for mounting the two groups of point laser sources 10 and the two groups of cameras 11.

[0057] Preferably, the device further comprises two groups of polarized light sheets (not shown in the figure) corresponding to the two groups of point laser sources 10; when the measured object is glass, especially thin glass, the reflection effect of the laser is relatively general, and the shooting of the two groups of point laser sources 10 due to the too small refraction angle deviation is prone to occur, which will cause the light emitting body of the glass to be burned out. The addition of the polarized light sheet (not shown in the figure) can avoid the burning out of the light emitting body.

[0058] Preferably, the device further comprises a partition plate (not shown in the figure) for preventing the shooting of the two groups of point laser sources 10 during debugging.

[0059] Preferably, one group of point laser sources 10 and one group of cameras 11 constitute one group of units 13; the mounting rack 12 comprises a main rack body 14; the upper and lower sides of the main rack body 14 are both slidingly connected with a first movable seat 15 moving along the Y axis; the first movable seat 15 is slidingly connected with a second movable seat 16 moving along the X axis; the two groups of units 13 are respectively mounted on the two groups of second movable seats 16, so as to adjust the positions of the two groups of units 13 respectively, and the use is more flexible.

[0060] It should be understood that those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall fall within the protection scope of the appended claims of the present application.

Claims

1. A method for high precision thickness measurement of large size objects, characterized in that, The method comprises the following steps: Two groups of point laser sources are used to emit oblique first laser and oblique second laser towards upper and lower surfaces of the measured object respectively; wherein the measured object is not a transparent object, and the two groups of point laser sources are coaxial; First coordinates of the corresponding reflection points of the first laser on the measured object and second coordinates of the corresponding reflection points of the second laser on the measured object are obtained, and an included angle θ between the first laser and a horizontal plane is obtained; Horizontal offset amounts ΔA and ΔB of the first coordinates and the second coordinates from a preset origin are calculated; A thickness H of the measured object is calculated as |ΔA-ΔB|*tag(θ); The step of obtaining the coordinates comprises: Two groups of cameras are used to obtain first images of the corresponding reflection points of the first laser on the measured object and second images of the corresponding reflection points of the second laser on the measured object respectively; wherein lenses of the two groups of cameras are directly opposite, the two groups of cameras are vertically placed, and a height of an overlapping part of the two groups of cameras is not less than an initial thickness of the measured object before processing; The first coordinates and the second coordinates are obtained according to the first images and the second images respectively; During debugging, a partition plate is set to prevent the two groups of point laser sources from being opposite.

2. A high-precision thickness measurement device for large-sized objects, based on the high-precision thickness measurement method for large-sized objects according to claim 1, characterized in that, The device comprises: Two groups of point laser sources coaxial during measurement; the two groups of point laser sources emit oblique first laser and oblique second laser towards upper and lower surfaces of the measured object respectively; and Two groups of cameras with directly opposite lenses during measurement; the two groups of cameras are vertically placed, and a height of an overlapping part of the two groups of cameras is not less than an initial thickness of the measured object before processing; and A mounting frame for mounting the two groups of point laser sources and the two groups of cameras.

3. The high precision thickness measuring device for large size objects according to claim 2, characterized in that, The device further comprises two groups of polarized light sheets corresponding to the two groups of point laser sources.

4. The high precision thickness measuring device for large size objects according to claim 2, characterized in that, One group of the point laser sources and one group of the cameras form a unit; the mounting frame comprises a main frame body; upper and lower sides of the main frame body are both slidably connected with first movable seats moving along a Y axis; the first movable seats are slidably connected with second movable seats moving along an X axis; the two groups of units are respectively mounted on the two groups of second movable seats.

Images