Integrated standard device for calibrating longitudinal resolution of terahertz measurement system

Abstract

The invention discloses an integrated standard device for calibrating the longitudinal resolution of a terahertz measurement system, which comprises a rectangular upper interface substrate and a step standard block, and is characterized in that the rectangular upper interface substrate is arranged above the step standard block, and the size of the rectangular upper interface substrate is larger than that of the step standard block; the upper end face of the step standard block is machined into a plurality of steps, the height specifications of the steps correspond to the longitudinal resolution of the terahertz measurement system, an upper measurement interface and a lower measurement interface are formed between the rectangular upper interface substrate and the steps of the step standard block, and terahertz waves reflected by the upper measurement interface and the lower measurement interface are measured through the terahertz measurement system. Whether the terahertz measurement system has the longitudinal resolution corresponding to the step height specification or not can be judged; the rectangular upper interface substrate and the step standard block are made of inorganic non-metal ceramic materials formed by natural or synthetic compounds through forming and high-temperature sintering. According to the invention, the test and calibration requirements of the terahertz measurement system on the longitudinal resolution index can be met, and the accuracy and consistency of the measurement result are ensured.

Description

Technical Field

[0001] The invention belongs to the field of geometric parameter calibration, and in particular relates to an integrated standard device for calibrating the longitudinal resolution of a terahertz measurement system. Background Art

[0002] With the rapid development of modern manufacturing, the requirements for material quality are also constantly increasing. In this process, the detection of internal defects in materials has become a key link in ensuring product quality. Tiny defects inside materials, such as cracks, holes, inclusions, etc., are often difficult to detect through traditional visual inspection methods, which requires more sophisticated detection technology to identify and evaluate. At present, the detection of internal defects in materials mainly relies on a variety of technical equipment, including ultrasonic testing, X-ray testing, magnetic particle testing, etc. These technologies have their own advantages. For example, ultrasonic testing is sensitive to internal defects in metals, X-ray testing can penetrate a variety of materials, and magnetic particle testing is suitable for detecting surface and near-surface defects of magnetic materials. However, they also have some limitations. For example, ultrasonic testing has restrictions on the thickness and shape of materials, X-ray testing has radiation risks, and magnetic particle testing is not suitable for non-magnetic materials. In recent years, terahertz measurement systems, as an emerging non-destructive testing technology, have attracted widespread attention due to their unique advantages. Terahertz waves have a wide frequency range, can penetrate a variety of materials, and are very sensitive to changes in the internal structure of materials, which makes terahertz measurement systems have great application potential in the field of non-destructive testing. Compared with traditional detection technologies, terahertz measurement systems do not need to contact the object being measured, have fast detection speed, high resolution, and no radiation hazards. With the widespread application of terahertz technology in materials science, biomedicine, safety inspection and other fields, the development and application of terahertz measurement systems are also increasing. In order to ensure the accuracy and reliability of the test results, the terahertz measurement system is mainly calibrated regularly. Calibration of key parameters of the terahertz measurement system can not only ensure the consistency and accuracy of the measurement results, but also improve the stability and repeatability of the measurement system, thereby providing a guarantee for the accurate identification and evaluation of material defects.

[0003] At present, the calibration of terahertz measurement systems mainly refers to the provisions on the calibration of radiative terahertz power meters in JJF1600-2016 "National Metrology Technical Specifications of the People's Republic of China". This specification covers the calibration methods for radiative terahertz power meters with a frequency range of 0.1THz to 10THz and a power range of 0.1mW to 3mW, including detailed descriptions of environmental conditions, metrological characteristics, calibration items and calibration methods. However, although this specification provides a basis for calibration of terahertz measurements, it does not include the calibration of the longitudinal resolution of geometric parameters that are closely related to the measurement capabilities of terahertz measurement systems. The longitudinal resolution of a terahertz measurement system refers to the ability of the system to distinguish between different levels inside a sample, which is crucial for non-destructive testing, material processing, and the entire manufacturing field. Insufficient longitudinal resolution will directly affect the accuracy and reliability of the test results, thereby affecting the quality of the material and the performance of the final product. In particular, more and more terahertz measurement systems (products) have factory specifications that explicitly include (longitudinal) resolution. However, when users conduct acceptance inspection, they have neither reference to acceptance standards and specifications nor corresponding test standards and calibration methods, making this key indicator impossible to verify, which brings greater uncontrollable quality risks to the delivery of terahertz measurement systems (products). Summary of the invention

[0004] The purpose of the present invention is to provide an integrated standard device for calibrating the longitudinal resolution of a terahertz measurement system, in order to address the problem that the longitudinal resolution of the existing terahertz measurement system cannot be calibrated. The standard device can meet the testing and calibration requirements of the terahertz measurement system for the longitudinal resolution index and ensure the accuracy and consistency of the measurement results.

[0005] One aspect of the present invention provides an integrated standard for calibrating the longitudinal resolution of a terahertz measurement system, comprising a rectangular upper interface substrate and a step standard block, wherein the rectangular upper interface substrate is arranged above the step standard block, and the size of the rectangular upper interface substrate is larger than that of the step standard block;

[0006] The upper end surface of the step standard block is processed into a plurality of steps, and the step height specification corresponds to the longitudinal resolution of the terahertz measurement system. The upper and lower measurement interfaces are formed between the rectangular upper interface substrate and the steps of the step standard block. The terahertz waves reflected by the upper and lower measurement interfaces are measured by the terahertz measurement system to determine whether the terahertz measurement system has the longitudinal resolution corresponding to the step height specification;

[0007] The rectangular upper interface substrate and the step standard block are made of inorganic non-metallic ceramic materials made by forming and high-temperature sintering natural or synthetic compounds;

[0008] The surface roughness of the upper and lower surfaces of the rectangular upper interface substrate is ≤0.2μm, the flatness is ≤1μm, and the parallelism is ≤3μm; the surface roughness of the upper and lower surfaces of the step standard block is ≤0.2μm, the flatness is ≤1μm, and the parallelism is ≤3μm.

[0009] Preferably, the step height specifications of the step standard block are 0.5 μm, 1 μm, 2 μm, 5 μm, and 10 μm.

[0010] Preferably, the inorganic non-metallic ceramic material is zirconia ceramic.

[0011] Preferably, the step height value of the step standard block is traced by a high-precision three-dimensional coordinate measuring machine or a step meter.

[0012] The integrated standard device for longitudinal resolution calibration of a terahertz measurement system according to the above aspects of the present invention can meet the testing and calibration requirements of the terahertz measurement system for longitudinal resolution indicators, and ensure the accuracy and consistency of the measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0014] Figure 1 It is a front view of an integrated standard device for longitudinal resolution calibration of a terahertz measurement system according to an embodiment of the present invention;

[0015] Figure 2 is a front view of an integrated standard for calibrating the longitudinal resolution of a terahertz measurement system according to an embodiment of the present invention;

[0016] Figure 3 The figure is a schematic diagram of the working principle of an integrated standard device for calibrating the longitudinal resolution of a terahertz measurement system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] One embodiment of the present invention provides an integrated standard for calibrating the longitudinal resolution of a terahertz measurement system, such as Figure 1 and Figure 2 As shown, the standard device includes a rectangular upper interface substrate 1 and a step standard block 2.

[0019] The upper end surface of the step standard block 2 is processed into multiple steps with a certain gradient difference. The step height corresponds to the longitudinal resolution of the terahertz measurement system. The preferred specifications are 0.5 μm, 1 μm, 2 μm, 5 μm, and 10 μm. The step height value of the step standard block 2 can be traced by a high-precision three-dimensional coordinate measuring machine or a step meter. The measurement uncertainty of the step nominal height of the step standard block 2 should be better than: U = 2nm + 6×10 -5 H, k = 2, H is the step height.

[0020] The rectangular upper interface substrate 1 is placed on the step standard block 2 to form an integrated step standard. The material of the rectangular upper interface substrate 1 can be selected from a type of inorganic non-metallic ceramic material zirconia ceramic made by forming and high-temperature sintering of natural or synthetic compounds; the material refractive index of the step standard block 2 is as large as possible compared to 1, preferably a type of inorganic non-metallic ceramic material zirconia ceramic made by forming and high-temperature sintering of natural or synthetic compounds, or a metal material. It can also be selected according to the material of the object to be measured by the terahertz system, which should be consistent with the material to be measured, or the material density (refractive index) is close to the material.

[0021] The processing technical requirements for the upper and lower surfaces of the rectangular upper interface substrate 1 are: surface roughness Ra≤0.2μm, flatness≤1μm, parallelism≤3μm; the processing technical requirements for the step standard block 2 are: roughness Ra≤0.2μm, flatness≤1μm, parallelism≤3μm.

[0022] An upper and lower measurement interface is formed between the rectangular upper interface substrate 1 and the step of the step standard block 2. By measuring the terahertz waves reflected from the upper and lower measurement interfaces by the terahertz measurement system, it is possible to determine whether the terahertz measurement system has a longitudinal resolution corresponding to the step height specification, thereby using the step standard height value to verify and calibrate the longitudinal resolution index of the terahertz measurement system.

[0023] like Figure 3 As shown, the working principle of the integrated standard for longitudinal resolution calibration of a terahertz measurement system according to an embodiment of the present invention is as follows:

[0024] The terahertz wave emitted by the terahertz measurement system hits the rectangular upper interface substrate 1 vertically, and reflects the terahertz wave A at the upper measurement interface (the lower surface of the rectangular upper interface substrate 1). At the same time, after the terahertz wave passes through the rectangular upper interface substrate 1, it reflects the terahertz wave B at the lower measurement interface (the upper surface of the step of the step standard block 2). The waveforms of the terahertz wave A and the terahertz wave B on the time domain coordinate axis are observed by the terahertz measurement system to determine whether the terahertz measurement system can output the waveform display normally and stably, or whether the flight time difference between the two can be extracted normally and stably, so as to confirm whether it has the longitudinal resolution capability corresponding to the step standard height specification. If the terahertz measurement system can output the waveform display normally and stably, or can extract the flight time difference between the two normally and stably, it can be considered that the terahertz measurement system has the ability to normally identify the step standard height specification of the standard, and the corresponding step standard height specification is the "longitudinal resolution" of the terahertz measurement system.

[0025] Compared with the prior art, the standard device of the embodiment of the present invention has the following beneficial effects:

[0026] 1. The present invention can meet the needs of longitudinal resolution index testing and calibration of terahertz measurement systems with different probe structures and sizes. The step standard block made of inorganic non-metallic ceramic material zirconium oxide ceramic has the advantages of large refractive index, uniform density, strong chemical stability, high wear resistance and good optical properties, and has been proven to be mature in the fields of optics and electronics.

[0027] 2. The present invention can form an upper and lower measurement interface through a step standard block and an upper interface substrate, and utilize the step standard height value to realize the test verification and calibration of the longitudinal resolution index of the terahertz measurement system, which has a very strong adaptability application prospect.

[0028] The integrated standard device for calibrating the longitudinal resolution of the terahertz measurement system in the embodiment of the present invention is the first and only one in China. Through the development and application of this standard device, the application potential and practical value of terahertz measurement technology in the fields of non-destructive testing, material processing and manufacturing can be further enhanced.

[0029] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An integrated standard for calibrating the longitudinal resolution of a terahertz measurement system, characterized in that: It comprises a rectangular upper interface substrate and a step standard block, wherein the rectangular upper interface substrate is arranged above the step standard block, and the size of the rectangular upper interface substrate is larger than that of the step standard block; The upper end surface of the step standard block is processed into a plurality of steps, and the step height specification corresponds to the longitudinal resolution of the terahertz measurement system. The upper and lower measurement interfaces are formed between the rectangular upper interface substrate and the steps of the step standard block. The terahertz waves reflected by the upper and lower measurement interfaces are measured by the terahertz measurement system to determine whether the terahertz measurement system has the longitudinal resolution corresponding to the step height specification; The rectangular upper interface substrate and the step standard block are made of inorganic non-metallic ceramic materials made by forming and high-temperature sintering natural or synthetic compounds; The surface roughness of the upper and lower surfaces of the rectangular upper interface substrate is ≤0.2μm, the flatness is ≤1μm, and the parallelism is ≤3μm; the surface roughness of the upper and lower surfaces of the step standard block is ≤0.2μm, the flatness is ≤1μm, and the parallelism is ≤3μm.

2. The standard device according to claim 1, characterized in that The step height specifications of the step standard block are 0.5 μm, 1 μm, 2 μm, 5 μm, and 10 μm.

3. The standard device according to claim 1 or 2, characterized in that: The inorganic non-metallic ceramic material is zirconia ceramic.

4. The standard device according to claim 1 or 2, characterized in that: The step height value of the step standard block is traced by a high-precision three-dimensional coordinate measuring machine or a step meter.

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