Laser measurement calibration method

Abstract

To provide a laser measurement calibration method for calibrating an error of non-contact measurement by a contact measurement result to improve the accuracy of the non-contact measurement.SOLUTION: A laser measurement calibration method includes the steps of: measuring a standard calibration member with a contact sensing device to acquire a measurement value; measuring the standard calibration member with at least one non-contact sensing device to acquire at least one surface distance value of the standard calibration member; calculating a calibration value on the basis of the measurement value of the standard calibration member and the at least one surface distance value of the standard calibration member; measuring an object to be measured with the at least one non-contact sensing device to acquire at least one surface distance value of the object to be measured; and calculating a measurement value of the object to be measured on the basis of the calibration value and the at least one surface distance value of the object to be measured.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a calibration method, in particular to a laser measurement calibration method. [Background technology]

[0002] Contact measurement is a method of measuring dimensions by directly contacting the surface of an object using a measuring device (such as a sensing probe). This type of measuring device is commonly used in the field of geometric dimension inspection in industrial production and manufacturing. The disadvantages of contact measurement include the inability to sample continuously and the susceptibility to surface damage.

[0003] Non-contact measurement, such as with lasers, uses laser light to scan the object being measured and calculates the distance and dimensions based on the reflected signal. This has the advantages of high accuracy, high efficiency, and not damaging the surface. However, lasers are susceptible to interference from environmental factors such as ambient temperature, humidity, and vibration, which can affect measurement accuracy.

[0004] Furthermore, if the material of the object being measured is different, the physical properties such as surface roughness, reflectivity, transparency, etc. will also affect the reflection and transmission of the laser signal, and further affect the measurement results. Therefore, non-contact measurement technology can only obtain rough values ​​(average values, etc.) depending on the specific application situation and differences in the material of the object being measured, and surface measurement errors will occur in the distance measured using laser light. Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiment of the present invention provides a laser measurement calibration method that calibrates the error of non-contact measurement by the contact measurement result, thereby improving the accuracy of the non-contact measurement. [Means for solving the problem]

[0006] An embodiment of the present invention provides a laser measurement calibration method that is incorporated into a software program and read by a computer, and is suitable for performing the following steps: measuring a standard calibration member with a contact sensor device and obtaining a measurement value; measuring the standard calibration member with at least one non-contact sensor device and obtaining at least one surface distance value of the standard calibration member; calculating a calibration value based on the measurement value of the standard calibration member and the at least one surface distance value of the standard calibration member; measuring a measurement object with at least one non-contact sensor device and obtaining at least one surface distance value of the measurement object; and calculating a measurement value of the measurement object based on the calibration value and the at least one surface distance value of the measurement object. [Effects of the Invention]

[0007] The laser measurement calibration method of the present invention can correct the error of the non-contact measurement using the contact measurement result, thereby improving the accuracy of the non-contact measurement. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an illustration of a measurement correction system according to the present invention; [Figure 2] 3 is a flowchart of a laser measurement calibration method according to the present invention. [Figure 3] 1 is an explanatory diagram of an embodiment of the laser measurement calibration method according to the present invention for measuring a standard calibration member. [Figure 4] 10A and 10B are explanatory diagrams of an embodiment of measuring a surface distance value of a standard calibration member of a non-contact sensor device according to the present invention; [Figure 5] 10A and 10B are explanatory diagrams of another embodiment of the non-contact sensor device according to the present invention for measuring the surface distance value of a standard calibration member. [Figure 6] 1 is an explanatory diagram of an embodiment of a non-contact sensor device according to the present invention for measuring a surface distance value of an object to be measured; DETAILED DESCRIPTION OF THE INVENTION

[0009] In order to make the present invention clearer and easier to understand, the following embodiments will be described in detail in conjunction with the drawings.

[0010] In the following, embodiments will be described in detail in combination with the drawings, but the provided embodiments are not used to limit the scope of the present invention. Furthermore, the drawings are for the purpose of explanation only and are not drawn to actual size. For ease of understanding, the same components will be denoted by the same reference numerals in the following description.

[0011] The terms "including," "comprising," "having," and the like used in the present invention are all open-ended terms, meaning "including but not limited to."

[0012] In describing each embodiment, when terms such as "first," "second," "third," and "fourth" are used to describe elements, they are used only to distinguish elements from one another and do not limit the order or importance of those elements.

[0013] In the description of each embodiment, the term "coupled" or "connected" can indicate that two or more elements are in direct physical or electrical contact with each other, or that they are in indirect physical or electrical contact with each other, and "coupled" or "connected" can also refer to the mutual operation or movement of two or more elements.

[0014] 1 is an explanatory diagram of a measurement calibration system according to the present invention. Referring to FIG. 1, the measurement calibration system 100 according to the present invention includes a contact sensor device 110, a non-contact sensor device 120, a controller 130, and a central control computer 140.

[0015] The central control computer 140 is connected to the controller 130 by signals and performs data processing and operational control of the entire measurement correction system 100. The controller 130 may be a physical circuit that controls and transmits signals to drives or actuators within various sensor devices. The central control computer 140 is, for example, a computer that executes a software program stored therein. The controller 130 may be installed within the central control computer 140, or the controller 130 may incorporate a software program that is stored in a storage drive within the computer and, after being read by a computer, for example, the central control computer 140, executes a series of expected method steps.

[0016] The contact sensor device 110 and the non-contact sensor device 120 are each connected to a controller 130. The present invention improves the accuracy of non-contact measurement by first measuring with the non-contact sensor device 120 and then correcting the errors of the non-contact sensor device 120, including minute errors and reflection errors, with the calibration value provided by the contact sensor device 110.

[0017] The contact sensor device 110 is a contact measurement technology that directly contacts the surface of an object to measure its specific properties, and typically uses various sensors, probes, or other devices to obtain data on properties such as required size, shape, surface roughness, hardness, etc. using contact methods such as placing, touching, or clamping on the object to be measured.

[0018] The non-contact sensor device 120 typically uses a non-contact sensor or other device to measure specific properties of an object. Non-contact measurement techniques that do not require direct contact with the surface of the object include, for example, cameras, optical measurements such as laser ranging, infrared sensing, ultrasonic sensing, electromagnetic induction, and microwave sensing, which can obtain specific properties such as the distance, position, speed, size, shape, temperature, or conductivity of an object.

[0019] Fig. 2 is a flowchart of the laser measurement calibration method according to the present invention, and Fig. 3 is an explanatory diagram of one embodiment of the laser measurement calibration method according to the present invention for measuring a standard calibration member. Referring to Figs. 1 to 3, the laser measurement calibration method S100 of the present invention includes the following steps S110 to S150, and this laser measurement calibration method S100 is suitable for being incorporated into, for example, a software program or a firmware program, stored in a storage device of the central control computer 140 or the controller 130, and executed by the computer.

[0020] First, step S110 is performed to measure the standard calibration member 50 using the contact sensor device 110 to obtain a measurement value PC. For example, the thickness value of the standard calibration member 50 is measured as the measurement value PC. The actual thickness value T of the standard calibration member 50 is known and stored in the controller 130, but a measurement error occurs due to surface roughness. This surface error value is the sum of the upper surface error value and the lower surface error value, and is obtained as PC-T. The contact sensor device 110 typically uses various sensors, probes, or other devices placed on the standard calibration member 50 that needs to be measured to obtain the required measurement value PC. This error can also be considered as an error in placing or mounting the measurement target on the flat plate 70 or machine table.

[0021] In the above step S110, the same material as the measurement object 60 (see Figure 6) is selected as the standard calibration member 50. The measurement object 60 is the object to be measured by the non-contact sensor device 120 of the present invention, and the same material as the measurement object 60 is used as the standard calibration member 50 to reduce exceptional errors that may occur due to differences in materials.

[0022] It should be noted that the above-mentioned standard calibration member 50 is not a standard gauge block, and in the present invention, the same material as the measurement object 60 is used as the standard calibration member 50, and since its physical quantities such as surface roughness are unknown, it is necessary to measure it with the contact sensor device 110 to obtain the measurement value PC.

[0023] In the following, possible embodiments in which the contact sensor device 110 measures the standard calibration member 50 will be described by way of example.

[0024] In one embodiment, for example, a material with a rough surface is used as the standard calibration member 50, and a non-contact sensor device 120 (e.g., a laser) is used to measure the material with a rough surface, such as a steel plate metal. Light emitted from a laser can only determine the average value of the highest point of the convex parts and the lowest point of the concave parts on the surface of a material with a rough surface. However, the contact sensor device 110 contacts the standard calibration member 50 to obtain a measurement value PC. The contact sensor device 110 contacts the highest points on the top and bottom surfaces of the standard calibration member 50, and the value obtained by measuring the material with a rough surface using the non-contact sensor device 120 contains surface measurement errors. Therefore, in the present invention, the error is first corrected using the measurement results of the contact sensor device 110.

[0025] Instead of the material having the rough surface, an opaque material may be used, and even if the metal material is totally reflective, it can be measured by the above method.

[0026] In another embodiment, for example, a material having a glossy surface is used as the standard calibration member 50, for example, a wafer, and the contact sensor device 110 can use a ruby ​​probe to contact the surface of the standard calibration member 50 to obtain a measurement value PC.

[0027] Because the surface reflection coefficient of the wafer varies depending on the doping material, when measuring a material with a glossy surface using the non-contact sensor device 120, the laser reflectivity varies, resulting in differences in measurement accuracy. Therefore, the standard calibration member 50 is measured by contact with the contact sensor device 110, thereby reducing errors due to reflection.

[0028] Instead of the materials having the above-mentioned glossy surfaces, light-transmitting materials or materials having smooth surfaces may be used, and other similar materials besides wafers may also be measured by the above-mentioned method.

[0029] After the above step S110, step S120 is performed to measure the standard calibration member 50 with at least one non-contact sensor device 120 and obtain at least one surface distance value SD of the standard calibration member 50, which may contain a surface error value and need to be corrected or calibrated.

[0030] 4, the number of non-contact sensor devices 120 is one, which may be an upper laser measurement module 120A, such as a non-contact type such as infrared sensing, ultrasonic sensing, electromagnetic induction, or microwave sensing, and is disposed above the flat plate 70, and the standard calibration member 50 is supported by the flat plate 70. The distance from the beam emitted by the upper laser measurement module 120A to the top surface of the standard calibration member 50 is the top surface distance value SD1. In addition, there is a sensor pitch K1 between the upper laser measurement module 120A and the flat plate 70.

[0031] 5, there are two non-contact sensor devices 120: an upper laser measurement module 120A and a lower laser measurement module 120B. These non-contact sensor devices are, for example, infrared sensing, ultrasonic sensing, electromagnetic induction, or microwave sensing. The upper laser measurement module 120A and the lower laser measurement module 120B are provided on the upper and lower sides of the standard calibration member 50, respectively. The flat plate 70 is not shown. The distance from the beam emitted by the upper laser measurement module 120A to the upper surface of the standard calibration member 50 is an upper surface distance value SD1, and the distance from the beam emitted by the lower laser measurement module 120B to the lower surface of the standard calibration member 50 is a lower surface distance value SD2. There is also a sensor pitch K2 between the upper laser measurement module 120A and the lower laser measurement module 120B.

[0032] After performing step S120, proceed to step S130, calculate a calibration value R based on the measurement value PC of the standard calibration member 50 and at least one surface distance value SD of the standard calibration member 50, where the calibration value R is obtained after correcting the surface distance value SD. The calibration value R is the at least one surface distance value SD of the standard calibration member 50 plus at least one error value, where the at least one error value includes any one or a combination of a surface error value, an assembly error value, an environmental drift value, and a reflection error value.

[0033] 3 and 4, the controller 130 receives the measurement value PC and the top surface distance value SD1 of the standard calibration member 50. For example, in the case of thickness, the measurement value PC of the standard calibration member 50 is equal to the sensor pitch K1 minus the top surface distance value SD1. Therefore, when using the top surface distance value SD1 of the standard calibration member 50, the error of the top surface roughness must be added to correct it to the calibration value R = K1 - PC (PC - T) = K1 - T. This calibration value R only calculates the error of the top surface of the standard calibration member 50. The contact error between the bottom surface of the standard calibration member 50 and the flat plate 70 is regarded as an installation or assembly error value and must be further taken into account.

[0034] 3 and 5 as examples, the controller 130 receives the measurement value PC, the upper surface distance value SD1, and the lower surface distance value SD2 of the standard calibration member 50. Taking the thickness as an example, the measurement value PC of the standard calibration member 50 is equal to the sensor pitch 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) needs to be corrected to the calibration value R=K2-T.

[0035] In one embodiment, when a material having a rough surface is used as the standard calibration member 50 and a non-contact sensor device 120 is employed, the error values ​​that need to be taken into consideration are, for example, the sum of an assembly error value, an environmental factor drift value (Environmental Factor Drift), and a surface roughness measurement error value, which is used as the correction amount. The assembly error value may be the assembly error value of the contact or non-contact sensor device, the standard calibration member installation error value, the environmental factor drift value of errors caused by factors such as temperature, humidity, and vibration (such as laser drift), and the surface roughness measurement error value, and the present invention does not limit the type and quantity thereof.

[0036] In another embodiment, for example, a material with a glossy surface is used as the standard calibration member 50, and the correction amount is the sum of the assembly error value, environmental factor drift value, and light reflection error value of the non-contact sensor device 120. The assembly error value and environmental factor drift value are as described above, but a reflection error value occurs because the reflectance of materials with glossy surfaces such as wafers is different.

[0037] The calibration value R can be selected based on the actual material of the object 60 to be measured, and the calibration value R calculated through steps S110 to S130 can include a generally selected standard.

[0038] Step S140 measures a measurement object 60 made of the same material as the standard calibration member 50 using at least one non-contact sensor device 120, and obtains at least one surface distance value MD of the measurement object 60. This method is similar to that shown in Figure 4 above, and may also employ a method using two non-contact sensor devices 120.

[0039] After step S140 acquires the surface distance value MD and the sensor pitch K1 of the measurement object 60, step S150 is executed to calculate the measurement value CM of the measurement object 60 based on the calibration value R and at least one surface distance value of the measurement object 60. For example, the measurement value CM of the measurement object 60 is calculated based on the sum of the correction amounts of the error values, as follows: CM=K1-MD(PC-T), and this measurement value CM can be regarded as, for example, the thickness value or curvature value of the measurement object 60.

[0040] In summary, the present invention first corrects the errors of non-contact measurement by contact measurement, thereby improving the accuracy of non-contact measurement. Although the present invention describes the calculations for correcting various errors as described above, it does not limit the types and numbers of errors, nor does it limit the spirit and scope of the present invention.

[0041] Although the present invention has been disclosed by the above-mentioned embodiments, this does not limit the present invention, and a person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is based on what is defined in the claims below. [Explanation of symbols]

[0042] 50 Standard calibration materials 60 Measurement object 70 flat plate 100 Measurement Calibration System 110 Contact sensor device 120 Non-contact sensor device 120A Upper Laser Measurement Module 120B Lower Laser Measurement Module 130 Controller 140 Central Control Computer CM measurements K1 sensor pitch K2 sensor pitch PC Measurements R calibration value SD surface distance value MD surface distance value SD1 Top Distance Value SD2 bottom distance value S100 Laser Measurement Calibration Method S110 Step S120 Step S130 Step S140 Step S150 Step T actual thickness value

Claims

1. Once embedded in a software program and read by a computer, measuring a standard calibration member with a contact sensor device to obtain a measurement value; measuring the standard calibration member with at least one non-contact sensor device to obtain at least one surface distance value of the standard calibration member; calculating a calibration value based on the measurements of the standard calibration member and the at least one surface distance value of the standard calibration member; measuring a measurement object with the at least one non-contact sensor device to obtain at least one surface distance value of the measurement object; calculating a measurement value of the measurement object based on the calibration value and at least one surface distance value of the measurement object; A laser measurement calibration method suitable for performing the above.

2. In the step of measuring a standard calibration member by the contact sensor device and obtaining a measurement value, 2. The laser measurement calibration method according to claim 1, further comprising the step of selecting the same material as the measurement object as the standard calibration member.

3. In the step of selecting the same material as the measurement object as the standard calibration member, A step of using a material having a rough surface as the standard calibration member; contacting the standard calibration member in a contact manner to obtain the measurement; 3. The laser measurement calibration method of claim 2, comprising:

4. 2. The method of claim 1, wherein the calibration value is the at least one surface distance value of the standard calibration member plus at least one error value.

5. The laser measurement calibration method of claim 4 , wherein the at least one error value includes any one or combination of a surface error value, an assembly error value, an environmental factor drift value, and a reflection error value.

6. measuring the standard calibration member with the non-contact sensor device and obtaining the measurement, 2. The laser measurement calibration method according to claim 1, further comprising the step of measuring the thickness value of the standard component and setting the measured value as the thickness value.

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