Laser measurement correction method

Abstract

The invention relates to a laser measurement correction method, which comprises the following steps of: measuring a standard correction piece by using a contact type sensing device to obtain a measurement value; measuring the standard correction piece by at least one non-contact sensing device to obtain at least one surface distance value of the standard correction piece; calculating a correction value according to the measured value of the standard correction piece and at least one surface distance value of the standard correction piece; measuring an object to be measured by at least one non-contact sensing device to obtain at least one surface distance value of the object to be measured; and calculating a measurement value of the object to be measured according to the correction value and at least one surface distance value of the object to be measured.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a correction method, in particular, to a laser measurement correction method. BACKGROUND

[0002] Contact measurement is a way of measuring the size of an object by directly contacting the surface of the object with a measuring device, such as a sensing probe. This type of measuring device is commonly used in the field of geometric dimension detection in industrial production and manufacturing. The disadvantage of contact measurement is that it cannot be continuously sampled and is prone to damaging the surface.

[0003] In non-contact measurement, such as laser, a laser beam is used to scan the surface of the measured object, and the distance and size are calculated based on the reflected signal. Although non-contact measurement has the advantages of high precision, high efficiency, and no damage to the surface, it is often affected by environmental factors such as temperature, humidity, and vibration, which affect the measurement accuracy.

[0004] Furthermore, the physical properties of the measured object, such as surface roughness, reflectivity, and transparency, also affect the reflection and transmission of the laser signal, which in turn affects the measurement result. Therefore, the non-contact measurement technology can only obtain an approximate value (such as the average value) according to the specific application scenario and the material of the measured object, and the distance measured by the laser beam will have a surface measurement error. SUMMARY

[0005] The present disclosure provides a laser measurement correction method, which corrects the error of non-contact measurement by using the results of contact measurement to improve the accuracy of non-contact measurement.

[0006] One embodiment of the present disclosure provides a laser measurement correction method, which is suitable for being established in a software program and executed by a computer after being read by the computer to perform the following steps: measuring a standard correction member with a contact sensing device to obtain a measurement value; measuring the standard correction member with at least one non-contact sensing device to obtain at least one surface distance value of the standard correction member; calculating a correction value based on the measurement value of the standard correction member and the at least one surface distance value of the standard correction member; measuring a measured object with at least one non-contact sensing device to obtain at least one surface distance value of the measured object; and calculating a measurement value of the measured object based on the correction value and the at least one surface distance value of the measured object.

[0007] In order to make the present disclosure more apparent and easy to understand, the following embodiments are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 A schematic diagram of a measurement correction system according to the present disclosure.

[0009] Figure 2 Flowchart of a laser measurement correction method according to the present disclosure.

[0010] Figure 3 Schematic diagram of an embodiment of a measurement standard correction piece for a laser measurement correction method according to the present disclosure.

[0011] Figure 4 Schematic diagram of an embodiment of a surface distance value of a measurement standard correction piece for a non-contact sensing device according to the present disclosure.

[0012] Figure 5 Schematic diagram of another embodiment of a surface distance value of a measurement standard correction piece for a non-contact sensing device according to the present disclosure.

[0013] Figure 6 Schematic diagram of an embodiment of a surface distance value of a measurement object for a non-contact sensing device according to the present disclosure.

[0014]

Symbol explanation

[0015] 50: Measurement standard correction piece

[0016] 60: Measurement object

[0017] 70: Flat plate piece

[0018] 100: Measurement correction system

[0019] 110: Contact sensing device

[0020] 120: Non-contact sensing device

[0021] 120A: Upper laser measurement module

[0022] 120B: Lower laser measurement module

[0023] 130: Controller

[0024] 140: Central control computer

[0025] CM: Measurement value

[0026] K1, K2: Sensor interval

[0027] PC: Measurement value

[0028] R: Correction value

[0029] SD, MD: Surface distance value

[0030] SD1: Upper surface distance value

[0031] SD2: Lower surface distance value

[0032] S100: Laser measurement correction method

[0033] S110-S150: Steps

[0034] T: True thickness value DETAILED DESCRIPTION

[0035] Embodiments are described below with reference to the accompanying drawings, which are provided for illustration purposes only and are not intended to limit the scope of the present disclosure. In addition, the drawings are not drawn to scale. For ease of understanding, the same elements will be identified with the same reference numerals throughout the description.

[0036] The terms "include", "comprise", "have", and the like as used herein are open terms that are intended to mean "including but not limited to".

[0037] In the description of various embodiments, when elements are referred to as "first", "second", "third", "fourth", etc., these are used only for distinguishing between two or more elements, and do not limit the order or the importance of the elements.

[0038] In the description of various embodiments, "coupled" or "connected" can mean that two or more elements are in direct physical or electrical contact with each other, or that two or more elements are not in direct contact with each other, but are still operated or actuated with each other.

[0039] Figure 1 A schematic diagram of a measurement correction system according to the present disclosure. Please refer to Figure 1 The measurement correction system 100 of the present disclosure includes a contact sensing device 110, a non-contact sensing device 120, a controller 130, and a central computer 140.

[0040] The central computer 140 is signal connected to the controller 130 to realize data processing and action control of the entire measurement correction system 100. The controller 130 can be a physical circuit to control the drive or actuator inside various sensing devices; the central computer 140 can be a computer to execute the software program stored therein; the controller 130 can be built in the central computer 140, or the controller 130 can be built in a software program stored in the storage drive of the computer and read by the computer, such as the central computer 140, to execute a series of intended method steps.

[0041] The contact sensing device 110 and the non-contact sensing device 120 are connected to the controller 130. The present disclosure first measures with the non-contact sensing device 120 and uses the correction value provided by the contact sensing device 110 to correct the error of the non-contact sensing device 120, which includes microscopic error and reflection error, to improve the accuracy of the non-contact measurement.

[0042] The contact sensing device 110 is a contact measurement technology that directly contacts the surface of an object to measure its specific properties, which usually uses various sensors, probes or other devices to be placed, contacted, clamped or contacted in other ways on the object to be measured to obtain the required properties such as size, shape, surface roughness, hardness, etc.

[0043] The non-contact sensing device 120 is a non-contact measurement technology that usually uses non-contact sensors or other devices to measure the specific properties of an object without directly contacting the surface of the object, such as cameras, optical measurements of laser ranging, infrared sensing, ultrasonic sensing, electromagnetic induction, microwave sensing, etc. Non-contact methods are used to obtain specific properties such as distance, position, speed, size, shape, temperature, or conductivity of the object.

[0044] Figure 2 The flowchart of the laser measurement correction method according to the present disclosure is shown in Figure 1, Figure 3 The schematic diagram of an embodiment of the standard correction piece measured by the laser measurement correction method according to the present disclosure is shown in Figure 2. Please refer to Figures 1 to 3 The laser measurement correction method S100 of the present disclosure includes the following steps S110 to S150, which is stored in the memory of the central control computer 140 or the controller 130 and executed by the computer, for example, suitable for being established in a software program or firmware program.

[0045] First, step S110 is performed to measure a standard correction piece 50 with a contact sensing device 110 to obtain a measurement value PC. For example, the thickness value of the standard correction piece 50 is measured as the measurement value PC. Since the true thickness value T of the standard correction piece 50 is known and stored in the controller 130, but there is a measurement error due to surface roughness, the surface error value is the sum of the upper surface error value and the lower surface error value, that is, PC-T. The contact sensing device 110 usually uses various sensors, probes or other devices to be placed on the standard correction piece 50 to be measured to obtain the required measurement value PC, and this error can also be considered as the error of placing or installing the measured object on the flat piece 70 or the machine table.

[0046] In the above step S110, the measured object 60 (such as the standard correction piece 50) is selected to have a certain surface roughness, and the contact sensing device 110 is used to measure the surface roughness of the measured object 60. Figure 6The same material as the measured object 60 is used as the standard correction piece 50, and the same material as the measured object 60 is used as the standard correction piece 50 to reduce the exceptional error caused by different materials.

[0047] It should be noted that the above-mentioned standard correction piece 50 is not a standard gauge block. The material of the same material as the measured object 60 is used as the standard correction piece 50, and the surface roughness and other physical quantities are still unknown, so the contact sensing device 110 is used to measure the measurement value PC.

[0048] The following examples illustrate the possible implementation of the contact sensing device 110 measuring the standard correction piece 50.

[0049] In an embodiment, for example, a material with a rough surface is used as the standard correction piece 50. If the non-contact sensing device 120 (such as a laser) is used to measure the metal with a rough surface, such as a steel plate, the light beam emitted by the laser can only obtain an average value, that is, the average value of the highest point of the convex surface and the lowest point of the concave surface of the material with a rough surface. However, the contact sensing device 110 contacts the standard correction piece 50 in a contact manner to obtain the measurement value PC. Since the contact sensing device 110 contacts the highest point of the upper and lower surfaces of the standard correction piece 50, and the value obtained by the non-contact sensing device 120 measuring the material with a rough surface will include surface measurement error, the disclosure first corrects the error using the measurement result of the contact sensing device 110.

[0050] The above-mentioned material with a rough surface can be replaced by a material that is not transparent, such as a metal material that is totally reflective, and can be measured in the above-mentioned manner.

[0051] In another embodiment, for example, a material with a shiny surface is used as the standard correction piece 50. For example, a wafer is used as the standard correction piece 50, and the contact sensing device 110 can use a ruby probe to contact the surface of the standard correction piece 50 to obtain the measurement value PC.

[0052] Since the wafer will cause the surface reflectance to be different due to different doping substances, if the non-contact sensing device 120 is used to measure the material with a shiny surface, the laser reflectivity will be different, resulting in a difference in measurement accuracy. Therefore, the contact sensing device 110 is used to contact and measure the standard correction piece 50, which will reduce the error caused by reflection.

[0053] The above-mentioned material with a shiny surface can be replaced by a material that is transparent or has a smooth surface. In addition to wafers, other similar materials can also be measured in the above-mentioned manner.

[0054] After step S110 , step S120 is performed to measure the standard calibration piece 50 with at least one non-contact sensing device 120 to obtain at least one surface distance value SD of the standard calibration piece 50 . This value may include a surface error value that needs to be corrected or calibrated.

[0055] In one embodiment, if Figure 4 As shown, there is one non-contact sensing device 120, which can be an upper laser measurement module 120A, employing other non-contact sensing methods such as infrared, ultrasonic, electromagnetic, or microwave sensing. It is positioned above a flat plate 70, which supports a standard calibration component 50. The distance between the light beam emitted by upper laser measurement module 120A and the top surface of standard calibration component 50 is defined as the top surface distance SD1. Furthermore, a sensor spacing K1 is defined between upper laser measurement module 120A and flat plate 70.

[0056] In another embodiment, if Figure 5 As shown, there are two non-contact sensing devices 120: an upper laser measurement module 120A and a lower laser measurement module 120B. These devices may employ non-contact sensing methods such as infrared, ultrasonic, electromagnetic, or microwave sensing. Upper and lower laser measurement modules 120A and 120B are located on the upper and lower sides of standard calibration component 50, respectively. Flat plate 70 is not shown. The distance between the beam emitted by upper laser measurement module 120A and the upper surface of standard calibration component 50 is the upper surface distance SD1, while the distance between the beam emitted by lower laser measurement module 120B and the lower surface of standard calibration component 50 is the lower surface distance SD2. Furthermore, a sensor spacing K2 is defined between upper and lower laser measurement modules 120A and 120B.

[0057] After step S120, step S130 proceeds to calculate a calibration value R based on the measured value PC of the calibration standard 50 and at least one surface distance value SD of the calibration standard 50. This calibration value R is obtained by correcting the surface distance value SD. The calibration value R is the at least one surface distance value SD of the calibration standard 50 plus at least one error value. The at least one error value can include any one or a combination of surface error, assembly error, environmental drift, and reflection error.

[0058] by Figure 3 and Figure 4For example, the controller 130 receives the measured value PC of the standard correction member 50 and the upper surface distance value SD1, and the measured value PC of the standard correction member 50 is equal to the sensor spacing K1 minus the upper surface distance value SD1. Therefore, the upper surface distance value SD1 of the standard correction member 50 must be added with the upper surface roughness error and should be corrected to the correction value R = K1 - PC + (PC - T) = K1 - T, and the correction value R only calculates the upper surface error of the standard correction member 50, and the error of the lower surface of the standard correction member 50 in contact with the flat member 70 is considered as the installation or assembly error value and must be considered again.

[0059] For example, the controller 130 receives the measured value PC of the standard correction member 50 and the upper surface distance value SD1, and the measured value PC of the standard correction member 50 is equal to the sensor spacing K1 minus the upper surface distance value SD1. Therefore, the upper surface distance value SD1 of the standard correction member 50 must be added with the upper surface roughness error and should be corrected to the correction value R = K1 - PC + (PC - T) = K1 - T, and the correction value R only calculates the upper surface error of the standard correction member 50, and the error of the lower surface of the standard correction member 50 in contact with the flat member 70 is considered as the installation or assembly error value and must be considered again. Figure 3 Figure 5 For example, the controller 130 receives the measured value PC of the standard correction member 50, the upper surface distance value SD1, and the lower surface distance value SD2, and the measured value PC of the standard correction member 50 is equal to the sensor spacing K2 minus the upper surface distance value SD1 and the lower surface distance value SD2. Therefore, the sum of the surface distance values (the upper surface distance value SD1 and the lower surface distance value SD2) should be corrected to the correction value R = K2 - T.

[0060] In one embodiment, if the material with rough surface is used as the standard correction member 50 and the non-contact sensing device 120 is used, the error values to be considered include the sum of the assembly error value, the environmental factor drift value, and the surface roughness measurement error value as the correction amount, wherein the assembly error value can be the assembly error value of the contact or non-contact sensing device, the installation error value of the standard correction member, the environmental factor drift value such as the error caused by temperature, humidity, vibration, etc. (such as laser drift amount), the surface roughness measurement error value, etc., and the present disclosure does not limit the types and quantities thereof.

[0061] In another embodiment, for example, the material with bright surface is used as the standard correction member 50, and the sum of the assembly error value, the environmental factor drift value, and the optical reflection error value of the non-contact sensing device 120 is used as the correction amount, wherein the assembly error value and the environmental factor drift value are as described above, and the material with bright surface such as wafer has different reflectivity and thus generates the reflection error value.

[0062] It should be noted that the above correction value R can be selected according to the actual material of the measured object 60, and the correction value R calculated after the above steps S110 to S130 is performed can generally include the selected standard.

[0063] The step S140 measures the measured object 60 with the same material as the standard correction member 50 by at least one non-contact sensing device 120 to obtain at least one surface distance value MD of the measured object 60, and the method is the same as the above​Figure 4 Similarly, two non-contact sensing devices 120 can also be used.

[0064] After the surface distance value MD of the object 60 and the sensor distance K1 are obtained in step S140, step S150 is performed to calculate the measurement value CM of the object 60 according to the correction value R and at least one surface distance value MD of the object 60. For example, the measurement value CM of the object 60 is calculated according to the sum of the correction values of the error values, such as CM = K1 - MD + (PC - T). The measurement value CM can be regarded as the thickness value or the curvature value of the object 60.

[0065] In summary, the present disclosure first corrects the error of the non-contact measurement by the contact measurement to improve the accuracy of the non-contact measurement. Although the calculation of the correction of each type of error is illustrated above, the present disclosure is not limited to the type and number of errors, and cannot be used to limit the spirit and scope of the present disclosure.

[0066] Although the present disclosure has been disclosed as above with examples, it is not intended to limit the present disclosure, and those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the scope defined by the appended claims.

Claims

1. A laser measurement calibration method suitable for being built into a software program and read by a computer to perform the following steps: Measuring the standard calibration piece with a contact sensing device to obtain a measurement value; Measuring the standard calibration piece with at least one non-contact sensing device to obtain at least one surface distance value of the standard calibration piece; Calculating a calibration value based on the measurement value of the standard calibration piece and the at least one surface distance value of the standard calibration piece; Measuring the object to be measured with the at least one non-contact sensing device to obtain at least one surface distance value of the object to be measured; as well as A measurement value of the object to be measured is calculated according to the calibration value and at least one surface distance value of the object to be measured.

2. The laser measurement and calibration method according to claim 1, wherein the step of measuring the standard calibration piece with the contact sensing device to obtain the measurement value comprises the following steps: Select a piece of material that is the same as the object to be measured as the standard calibration piece.

3. The laser measurement calibration method according to claim 2, wherein the step of selecting a piece made of the same material as the object to be measured as the standard calibration piece comprises the following steps: Using a material with a rough surface as the standard calibration piece; and The standard calibration piece is contacted to obtain the measurement value. 4 . The laser measurement calibration method according to claim 1 , wherein the calibration value is the at least one surface distance value of the standard calibration piece plus at least one error value. 5 . The laser measurement and calibration method according to claim 4 , wherein the at least one error value comprises any one or a combination of a surface error value, an assembly error value, an environmental drift value, and a reflection error value.

6. The laser measurement and calibration method according to claim 1, wherein the step of measuring the standard calibration piece with the contact sensing device to obtain the measurement value comprises the following steps: The thickness of the standard calibration piece is measured as the measured value.

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