JP7530233B2 - Surface condition information acquisition device - Google Patents

Description

The present invention relates to a surface condition information acquisition device that acquires the surface roughness of a measurement spot based on the ratio of the radiance of p-polarized light and the radiance of s-polarized light emitted from the measurement spot on a measurement object.

For example, in the hot-dip galvanized steel sheet manufacturing process, the temperature of the galvanized steel sheet that has passed through a galvanizing bath and is then introduced into an alloying furnace is sometimes measured when it leaves the alloying furnace, and a radiation thermometer is used to perform this online temperature measurement.

A radiation thermometer measures the intensity of thermal radiation (radiance) from the object being measured, and converts radiance to temperature based on its relationship to the radiance of a blackbody. If the emissivity of the object being measured differs from that of a blackbody (ε = 1.0), a correction is made using the emissivity of the object being measured (for example, the oxidized surface of aluminum has an emissivity of ε = 0.4).

In the above-mentioned hot-dip galvanized steel sheet manufacturing process, when an alloy layer with zinc is formed on the surface of the steel material, the surface becomes rough as the alloying progresses. Here, surface roughness correlates with the surface emissivity. The emissivity ε and reflectivity ρ are related by ρ = 1 - ε based on Kirchhoff's law and the law of conservation of energy, and the reflectivity ρ depends on the surface properties such as roughness.

Therefore, the reflectance of the surface changes depending on the progress of alloying of the surface, and the change in reflectance causes the emissivity to change, making it impossible to properly correct the emissivity in temperature measurement.

By using a non-contact surface roughness measurement method, it is possible to perform online surface roughness measurement while performing appropriate emissivity correction. One example of such a surface roughness measurement method is the surface roughness measurement method described in Patent Document 1.

Japanese Patent Application Publication No. 6-294637

To carry out the surface roughness measurement method of Patent Document 1, at least a laser light source that irradiates a laser light onto the surface of the measurement object, and a laser light receiving element that receives the light scattered by the irradiated laser light on the surface, are required. Therefore, in order to measure the surface roughness of the measurement object while measuring the temperature of the measurement object using a radiation thermometer, it is necessary to install each measurement system together, which poses a problem of taking up a large installation space.

In order to solve the above problem, the first invention provides a surface condition information acquisition device for a measurement object, the device having a radiation receiving unit that receives radiation from a predetermined measurement spot on the measurement object, a p-polarized radiance acquisition unit that acquires p-polarized radiance from the radiation receiving unit, an s-polarized radiance acquisition unit that acquires s-polarized radiance from the radiation receiving unit, a ps ratio calculation unit that calculates a ps ratio between the acquired p-polarized radiance and s-polarized radiance, and a surface roughness information acquisition unit that acquires surface roughness information, which is information indicating the surface roughness of the measurement object, based on the acquired ps ratio and ps ratio/surface roughness correlation information acquired in advance for the measurement object.

As a second invention, the measurement object is an alloy, and the surface condition information acquisition device according to the first invention is further provided, which has an alloying progress information acquisition unit that acquires alloying progress information, which is information showing the progress of alloying of the measurement object, based on the acquired surface roughness information.

The third invention provides a surface condition information acquisition device according to the first or second invention, further comprising an angle change unit capable of changing the angle of incidence at which the synchrotron radiation receiving unit focuses on the measurement spot, and the ps ratio/surface roughness correlation information previously acquired for the measurement object is held for a plurality of angles of incidence, and the surface roughness information acquisition unit comprises an incident angle-specific surface roughness information acquisition means for acquiring incident angle-specific surface roughness information, which is information showing the surface roughness of the measurement object for each of the plurality of angles.

The fourth invention provides a surface condition information acquisition device according to any one of the first to third inventions, further comprising a p-polarized blackbody temperature calibration curve information storage unit having p-polarized blackbody temperature calibration curve information showing the relationship between p-polarized radiance and the surface temperature of a blackbody, and a temperature acquisition unit that acquires the temperature of the measurement spot from the acquired p-polarized radiance and the stored p-polarized blackbody temperature calibration curve information.

The fifth invention provides a surface condition information acquisition device according to any one of the first to fourth inventions, further comprising an s-polarized blackbody temperature calibration curve information storage unit having s-polarized blackbody temperature calibration curve information showing the relationship between s-polarized radiance and the surface temperature of a blackbody, and a temperature acquisition unit that acquires the temperature of the measurement spot from the acquired s-polarized radiance and the stored s-polarized blackbody temperature calibration curve information.

The sixth invention provides a method for acquiring surface condition information of a measurement object, the method comprising: a radiation light receiving step of receiving radiation light from a predetermined measurement spot on the measurement object; a p-polarized radiance acquisition step of acquiring p-polarized radiance from the received radiation light; an s-polarized radiance acquisition step of acquiring s-polarized radiance from the received radiation light; a ps ratio calculation step of calculating a ps ratio between the acquired p-polarized radiance and s-polarized radiance; and a surface roughness information acquisition step of acquiring surface roughness information, which is information indicating the surface roughness of the measurement object, based on the acquired ps ratio and ps ratio/surface roughness correlation information acquired in advance for the measurement object.

The present invention provides a surface condition information acquisition device that can receive synchrotron radiation and measure the surface roughness of an object to be measured, without the need to install a dedicated measurement system for measuring the surface roughness of the object to be measured.

FIG. 1 is a functional block diagram showing an example of a surface condition information acquisition device according to a first embodiment. FIG. 1 is a conceptual diagram showing an example of how p-polarized radiance and s-polarized radiance are acquired. Angular characteristics of polarized emissivity, emissivity ratio, and polarization ratio of various samples FIG. 1A is a diagram showing the relationship between the polarized emissivity ratio ε _s /ε _p and the arithmetic surface roughness Ra, and FIG. 1B is a diagram showing the relationship between the proportion of polarized light (dep) and the arithmetic mean surface roughness Ra. FIG. 1 is a conceptual diagram showing an example of a computer that realizes a surface state information acquisition device according to a first embodiment. FIG. 1 is a flow chart showing an example of a process flow of the surface state information acquisition device according to the first embodiment; FIG. 1 is a conceptual diagram showing an example of another aspect of acquiring p-polarized radiance and s-polarized radiance. FIG. 11 is a functional block diagram showing an example of a surface condition information acquisition device according to a second embodiment. FIG. 11 is a flow chart showing an example of a process flow of the surface condition information acquisition device according to the second embodiment. FIG. 11 is a functional block diagram showing an example of a surface condition information acquisition device according to a third embodiment. FIG. 13 is a functional block diagram showing an example of a surface condition information acquisition device according to a fourth embodiment. FIG. 13 is a conceptual diagram showing an example of a radiation thermometry device according to a fifth embodiment. A conceptual diagram showing an example of a means for measuring the reflection distribution coefficient γ Relationship between ps ratio and parameter α

The following describes embodiments of the present invention with reference to the accompanying drawings. Note that the present invention should not be limited to these embodiments, and may be implemented in various forms without departing from the spirit of the present invention.

The functional configuration of each embodiment described below can be realized as a combination of hardware and software, which will be described later. Each embodiment described in this specification can be realized not only as an apparatus, but also as a method of operation, in part or in whole. A part of such an apparatus can be configured as software. Furthermore, software products used to cause a computer to execute such software, and recording media on which such products are fixed, are naturally included in the technical scope of each embodiment described in this specification (the same applies throughout this specification).
<Embodiment 1>
<Overview of First Embodiment>

The surface condition information acquisition device of this embodiment is a surface condition information acquisition device that acquires in advance the correlation between the ratio of p-polarized radiance and s-polarized radiance emitted from the object to be measured and the surface roughness of the object to be measured, and acquires the surface roughness of the object to be measured based on the ratio of p-polarized radiance and s-polarized radiance (which can be expressed as p-polarized emissivity and s-polarized emissivity) acquired during measurement and said correlation.
<Principle of the invention>

When the surface roughness of the object to be measured is small and the surface is a mirror surface, as shown in Figure 3, the emissivity of the radiation receiving part focused at an incident angle of about 20 degrees to 85 degrees with respect to the normal direction of the measurement spot has anisotropy for p-polarized light and s-polarized light. However, as the surface roughness of the object to be measured increases and the light becomes rough, the anisotropy is lost due to multiple reflections from minute irregularities on the surface, and eventually the anisotropy is completely lost, and the p-polarized emissivity and the s-polarized emissivity become the same value. In other words, the surface roughness of the object to be measured is expressed as an increasing function that increases (becomes rougher) as the ratio of p-polarized light to s-polarized light (s-polarized emissivity/p-polarized emissivity) approaches 1. Of course, the numerator and denominator relationship of ps may be reversed, and the functional relationship with the surface roughness is established without being limited to these values as long as the value is composed as a function of p-polarized emissivity and s-polarized emissivity.

Specifically, this functional relationship is expressed as the experimental results shown in FIGS.
<Configuration of First Embodiment>

1 is a functional block diagram showing an example of a surface condition information acquisition device according to the present embodiment. As shown in the figure, the surface condition information acquisition device 0100 according to the present embodiment includes a radiation receiving unit 0101, a p-polarized radiance acquisition unit 0102, an s-polarized radiance acquisition unit 0103, a ps ratio calculation unit 0104, and a surface roughness information acquisition unit 0105.
<Embodiment 1: Radiation light receiving unit>

Figure 2(a) is a conceptual diagram showing how radiation from a measurement spot is received. As shown in the figure, the radiation receiving unit 0201 is configured to receive radiation 0211 from a measurement spot at a predetermined angle of incidence θ with respect to the normal direction 0204 of a predetermined measurement spot S on the measurement object 0202.

The measurement object 0202 may be, for example, a zinc-plated steel sheet, a silicon wafer, an aluminum sheet, or the like. This figure shows a cross section of such an object to be measured. A conveying means 0203 for conveying the object to be measured may also be provided. In this figure, the object to be measured can be conveyed in the normal direction to the paper surface. By providing such a conveying means, the surface condition information acquisition device can measure the surface condition in an assembly line such as a hot-dip galvanized steel sheet manufacturing process.
<Embodiment 1: p-polarized radiance acquisition unit, s-polarized radiance acquisition unit>

The p-polarized radiance acquisition unit is configured to acquire p-polarized radiance from the synchrotron radiation receiving unit. The s-polarized radiance acquisition unit is configured to acquire s-polarized radiance from the synchrotron radiation receiving unit. Figure 2(b) is a conceptual diagram showing an example in which the synchrotron radiation receiving unit, the p-polarized radiance acquisition unit, and the s-polarized radiance acquisition unit are integrated together.

As shown in the figure, the radiation receiving unit 0205 receives the radiation 0211. The cube-shaped polarizing beam splitter 0206 reflects the s-polarized light 0207 of the received radiation at a right angle, and passes the p-polarized light 0208 of the received radiation, splitting the light into s-polarized light and p-polarized light. The s-polarized light is received by one infrared light receiving element 0209, and the p-polarized light is received by another infrared light receiving element 0210, and the s-polarized radiance and the p-polarized radiance are obtained by each light receiving element. Note that a plate-shaped beam splitter may be used instead of the cube-shaped beam splitter. With this configuration, the s-polarized radiance and the p-polarized radiance can be obtained simultaneously. The wavelengths of the s-polarized radiance and the p-polarized radiance to be obtained are selected according to the object to be measured. For example, a wavelength of 0.8 to 1.6 μm is selected for metal, a wavelength of 4.9 to 5.3 μm is selected for glass, and a wavelength of 8 to 14 μm is selected for rubber.
<First embodiment ps ratio calculation unit>

The ps ratio calculation unit is configured to calculate the ps ratio between the acquired p-polarized radiance and s-polarized radiance. As one of the ps ratios, s-polarized radiance/p-polarized radiance is calculated. If the s-polarized radiance and the p-polarized radiance are Ls _{, λ} (T) and _{Lp, λ} (T), respectively, the s-polarized emissivity and the p-polarized emissivity are _εs and _εp , respectively, and the blackbody spectral radiance at temperature T is Lb _{, λ} (T), the relationship between them can be expressed as the following formula.

When s-polarized light radiance/p-polarized light radiance is calculated using this formula, the polarized emissivity ratio ε _s /ε _p is obtained as shown in formula 2.

In addition, the polarization ratio (dep) may be calculated as another ps ratio. The polarization ratio is the value of (ε _p - ε _s )/(ε _p + ε _s ). The polarization ratio can also be expressed as follows using the above L _s,λ (T), L _p,λ (T), and L _b,λ (T):

FIG. 3 plots the s-polarized emissivity ε s , p-polarized emissivity ε p , polarized emissivity ratio ε _s /ε _p , and polarization ratio (ε p - ε _s )/(ε _p + ε _{s )} as a function of the incident angle θ for various samples (stainless steel SUS304, aluminum Al, zinc _Zinc , and silicon _Si ) based on the complex refractive index _at a specific wavelength (Table 1 below).
<Embodiment 1 Surface roughness information acquisition unit>

The surface roughness information acquiring unit acquires surface roughness information, which is information indicating the surface roughness of the object to be measured, based on the acquired ps ratio and ps ratio-surface roughness correlation information acquired in advance for the object to be measured. Examples of surface roughness information include arithmetic mean roughness Ra, maximum height Rz, and ten-point mean roughness Rzjis. The arithmetic mean roughness Ra refers to a value expressed in micrometers (μm) obtained by extracting only a reference length l (l) from the roughness curve in the direction of the mean line, taking the X-axis in the direction of the mean line in the depth direction of this extracted portion and the Y-axis in the direction of the longitudinal magnification, and expressing the roughness curve as y = f (x).
Here, the reference length l (mm) is three times or more the cutoff value (mm), and the cutoff value is 0.08 for the standard sequence 0.012a, 0.25 for the standard sequence 0.025a and 0.05a, 0.8 for the standard sequence 0.1a, 0.2a, 0.4a, 0.8a, and 1.6a, 2.5 for the standard sequence 3.2a and 6.3a, and 8 for the standard sequence 12.5a, 25a, and 50a.

The maximum height Rz is calculated by cutting out only the reference length l (mm) from the roughness curve in the direction of the average line, measuring the distance between the peak line and the valley line of this cut portion in the direction of the longitudinal magnification of the roughness curve, and expressing this value in micrometers (μm). The reference length is cut from a portion that does not have any exceptionally high peaks or deep valleys that could be considered scratches. The reference length l (mm) is 0.08 for the standard progression of 0.05s and 0.1s, 0.25 for the standard progression of 0.2s and 0.4s, 0.8 for the standard progression of 0.8s, 1.6s, 3.2s, and 6.3s, 2.5 for the standard progression of 12.5s, 25s, and 50s, and 8 for the standard progression of 100s and 200s.

The ten-point average roughness Rzjis is calculated by taking a reference length from the roughness curve in the direction of the average line, and then measuring from the average line of the taken portion in the direction of the longitudinal magnification, and calculating the sum of the average of the absolute values of the elevations (Yp) of the top five peaks from the highest peak and the average of the absolute values of the elevations (Yv) of the top five valleys from the lowest valley, and expressing this value in micrometers (μm). The reference length l (mm) is 0.08 for the standard progression 0.05z and 0.1z, 0.25 for the standard progression 0.2z and 0.4z, 0.8 for the standard progression 0.8z, 1.6z, 3.2z, and 6.3z, 2.5 for the standard progression 12.5z, 25z, and 50z, and 8 for the standard progression 100z and 200z.

As shown in FIG. 3 and Table 1, homogeneous, smooth, and flat samples such as metals and silicon semiconductors exhibit specular reflection characteristics, and at large angles (e.g., θ=75°), a large difference in the emissivity of p-polarized light and s-polarized light occurs. The difference becomes smaller as the surface roughness of the object to be measured increases and becomes rougher, and finally, the anisotropy is completely lost, and the p-polarized emissivity and the s-polarized emissivity become the same value. Therefore, for example, if the surface roughness is observed at an incidence angle in the range of about 60° to 85°, the sensitivity is good and the resolution of the surface roughness is high. Therefore, even a slight difference in surface roughness is reflected in the polarized emissivity ratio ε _s /ε _p and the proportion of polarization. The ratio of polarized emissivity becomes smaller as the incidence angle increases, but if ε s and ε p become too small, the S/N ratio becomes poor, so the incidence angle is preferably in the range of 65° to 75°.

4 shows (a) the relationship between the polarized emissivity ratio _εs / _εp and the arithmetic surface roughness Ra, and (b) the relationship between the degree of polarization (dep) and the arithmetic mean surface roughness Ra, based on experimental data. As shown in the figure, the polarized emissivity ratio and the proportion of polarized emissivity change with the change in surface roughness, and this relationship is obtained in advance as ps ratio-surface roughness correlation information.

In order to obtain the p-s ratio-surface roughness correlation information shown in Figure 4 in advance, a potential measurement target is used as a sample, and a thermocouple is attached to the surface of the sample, which is assumed to be the actual measurement spot, so that the temperature can be measured directly, for example by welding it to the spot. If necessary, the sample is heated to a range that can be measured by the radiation thermometer. Then, a radiation thermometer is placed at a predetermined incidence angle θ, and p-polarized radiance and s-polarized radiance are measured, and p-polarized emissivity and s-polarized emissivity are obtained based on the actual temperature of the measurement target measured by the thermocouple. In addition, the surface of the measurement spot of the measurement target is measured using a contact surface roughness measuring device. These measurements provide a correspondence relationship between p-polarized emissivity and s-polarized emissivity and surface roughness. Then, by repeating this measurement on multiple samples with different surface roughness, the relationship between the polarized emissivity ratio and the polarized emissivity ratio and the surface roughness as shown in Figure 4 can be obtained.

As shown in FIG. 4, when the incident angle θ is 75°, the variation range of the polarized emissivity ratio or the proportion of polarized emissivity to the surface roughness is large, which is preferable because it allows obtaining surface roughness information with relatively high sensitivity. Furthermore, the surface roughness information is not limited to the above-mentioned arithmetic mean surface roughness Ra, and may be information indicating surface roughness such as the ten-point mean surface roughness Rzjis or the maximum height Rz.

By acquiring and storing the above-described ps ratio/surface roughness correlation information in advance, it is possible to measure p-polarized radiance and s-polarized radiance in actual measurements, calculate the ps ratio, and acquire surface roughness information by applying it to the ps ratio/surface roughness correlation information.
First Embodiment Hardware Configuration

Figure 5 is a conceptual diagram showing an example of a computer that realizes the surface condition information acquisition device of embodiment 1. As shown in the figure, it is composed of a CPU 0501, non-volatile memory 0502, main memory 0503, graphics card 0504, an I/O controller 0505, interfaces 0506 such as USB, IEEE, and LAN, a BIOS 0507, a PCI slot 0508, a real-time clock 0509, etc., which are provided on a motherboard, as well as buses that interconnect these components and a chipset (north bridge, south bridge) 0510 that connects the buses.

The "chipset" 0510 is a set of large scale integrated circuits (LSIs) that are mounted on the computer's motherboard and integrate a communication function between the CPU's external bus and a standard bus that connects memory and peripheral devices, i.e. a bridge function. There are cases where a two-chipset configuration is used, and cases where a one-chipset configuration is used. The north bridge is located on the side closest to the CPU and main memory, and the south bridge is located on the side farther away and interfaces with the relatively slow external I/O.

The north bridge includes a CPU interface, memory controller, and graphics interface. With increasing integration, most of the functions of a conventional north bridge may be assumed by the CPU. The north bridge is connected to the memory slot of the main memory via a memory bus, and to the graphics card slot of the graphics card via a high-speed graphics bus (AGP, PCI Express).

The south bridge is connected to the PCI interface (PCI slot) via the PCI bus, and is responsible for I/O functions such as the ATA (SATA) interface, USB interface, and Ethernet interface, as well as sound functions. Since incorporating circuits to support PS/2 ports, floppy disk drives, serial ports, parallel ports, and ISA buses, which do not require or are not capable of high-speed operation, would hinder the speed of the chipset itself, it is acceptable to separate these from the south bridge chip and have them handled by a separate LSI called a super I/O chip.

The "bus" is provided to connect the CPU (MPU) to peripheral devices and various control units. The bus is also connected by the chipset mentioned above. The memory bus used to connect to the main memory may instead adopt a channel structure to increase speed. The bus can be a serial bus or a parallel bus. While a serial bus transfers data one bit at a time, a parallel bus transmits the original data itself or multiple bits extracted from the original data as a single block and simultaneously over multiple communication paths. A dedicated line for the clock signal is installed in parallel with the data line, and data demodulation is synchronized on the receiving side. It is also used as a bus to connect the front side bus (chipset) of the CPU to external devices. Types of buses include GPIB, IDE/(parallel) ATA, SCSI, PCI, etc. Since there is a limit to how fast it can be, the data line can be a serial bus in PCI Express, an improved version of PCI, and Serial ATA, an improved version of Parallel ATA.

The "CPU" (MPU) reads, in order, a sequence of instructions called a program stored in main memory, and interprets and executes it, outputting information consisting of signals onto the main memory as well. The CPU functions as the center of calculations within a computer. The CPU is made up of a CPU core, which is the center of calculations, and its peripheral parts, and includes registers, cache memory, an internal bus that connects the cache memory to the CPU core, a DMA controller, a timer, and an interface with the connection bus to the north bridge. A single CPU (chip) may have multiple CPU cores.

An example of "non-volatile memory" is a hard disk drive. The basic structure consists of a magnetic disk, a magnetic head, and an arm on which the magnetic head is mounted. SATA (previously ATA) can be used as the external interface. A high-performance controller, such as SCSI, is used to support communication between hard disk drives. For example, when copying a file to another hard disk drive, the controller can read the sectors and transfer them to the other hard disk drive for writing. At this time, the host CPU's memory is not accessed. Therefore, there is no increase in the load on the CPU.

As a non-volatile memory, an SSD consisting of a flash memory may be used together with an HDD, or may be used to replace an HDD.

Main memory is made up of volatile memory. The most typical type is DRAM (dynamic RAM).

The BIOS is used to load the operating system into the main memory when the computer starts up, and to make applications executable. As mentioned above, it is connected to the south bridge, but it may also be connected to the north bridge.

I/O controllers are used to connect to external devices. A USB connector is one example. Infrared light receiving elements, visible light receiving elements, etc. are connected to them, and they accept the input of their detection signals. Shutters and choppers are also connected, and signals to drive them are output.

The IEEE 1394 connector is the most common communication standard interface.

A PCI slot is an interface for connecting functional circuits to a computer.

An OS (operating system) is the basic software that runs a computer. It provides an interface for users and application programs, and plays a role in efficiently managing functional parts such as hardware and each resource.

A device driver is a program that controls the hardware of various devices attached to a computer so that they can be used by users and applications via the operating system.

The non-volatile memory 0502 stores various programs such as a radiation receiving program, a p-polarized radiance acquisition program, an s-polarized reflected luminance acquisition program, a ps ratio calculation program, and a surface roughness information acquisition program. In addition, various information such as p-polarized radiance Lp _,λ (T), s-polarized radiance Ls _,λ (T), the polarized emissivity ratio _εs / _εp as the ps ratio and the polarization ratio ( _εp - _εs )/( _εp + _εs ) as the surface roughness information, and the arithmetic mean surface roughness Ra and ps ratio/surface roughness correlation information are stored as data. These programs and data are loaded into the holding area of the main memory and executed in the working area.

It should be noted that the above-mentioned hardware configuration is an example assuming that a PC is used as the computer to realize the surface condition information acquisition device, but it can also be realized by a microcomputer that holds the various programs mentioned above and enables the input and output of necessary signals as appropriate.
<Processing flow of embodiment 1>

6 is a flow diagram showing an example of the process flow of this embodiment. First, the radiation is received (0601: radiation receiving step). Then, p-polarized radiance is obtained from the received radiation (0602: p-polarized radiance acquisition step). Then, s-polarized radiance is obtained from the received radiation (0603: s-polarized radiance acquisition step). Then, a ps ratio, which is the ratio between the obtained p-polarized radiance and the s-polarized radiance, is calculated (0604: ps ratio calculation step). Then, based on the obtained ps ratio and ps ratio/surface roughness correlation information previously obtained for the measurement object, surface roughness information, which is information indicating the surface roughness of the measurement object, is obtained (0605: surface roughness information acquisition step). Note that the p-polarized radiance acquisition step and the s-polarized radiance acquisition step are preferably performed simultaneously.
<Embodiment 1: Acquisition of p-polarized radiance and s-polarized radiance>

In the example of the surface condition information acquisition device shown in Figure 2, p-polarized radiance and s-polarized radiance were acquired using a polarizing beam splitter and multiple infrared light receiving elements. As another embodiment, as shown in Figure 7(a), a chopper with a polarizing element is used. As shown in the figure, a chopper 0705 equipped with a p-polarizing element 0703 and an s-polarizing element 0704 is placed in front of a radiation receiving unit 0701 equipped with an infrared light receiving element, on the light receiving axis line 0702 from the measurement spot.

Figure 7(b) is a conceptual diagram showing an example of the chopper described above. As shown in the figure, this chopper 0706 has four regions in which p-polarizing elements 0707 and s-polarizing elements 0708 are alternately arranged. When the p-polarizing element is located in front of the radiation receiving unit 0701, the infrared light receiving element provided in the radiation receiving unit receives the radiation that has passed through the p-polarizing element, thereby obtaining p-polarized radiance. Also, when the s-polarizing element is located in front of the radiation receiving unit 0701, the infrared light receiving element provided in the radiation receiving unit receives the radiation that has passed through the s-polarizing element, thereby obtaining s-polarized radiance. Also, as shown in Figure 7(c), by using a chopper 0709 that not only arranges the p-polarizing element 0710 and the s-polarizing element 0711 but also provides a non-polarized region 0712, temperature measurement can be performed as a general radiation thermometer. As described below, even if there is no chopper to provide a non-polarized region, it is possible to configure the device to measure the temperature of the measurement spot using p-polarized radiance or s-polarized radiance.

It is preferable to acquire p-polarized radiance and s-polarized radiance alternately and closely in time. As described above, the acquired p-polarized radiance and s-polarized radiance are used to calculate the ps ratio, which is the ratio between the two. Then, the surface roughness of the measurement spot is acquired based on the ps ratio. This is because, in theory, it is desirable to acquire the p-polarized radiance and the s-polarized radiance simultaneously in order to use the ps ratio.
<Effects of First Embodiment>

According to the surface condition information acquisition device of this embodiment, surface condition information can be acquired by receiving synchrotron radiation, and there is an advantage that there is no need to provide a measurement system solely for acquiring surface condition information.
<Embodiment 2>
<Overview of Second Embodiment>

The surface condition information acquisition device of this embodiment is based on embodiment 1 and can acquire alloying progress information that indicates the progress of alloying of the alloy, which is the measurement object, based on surface roughness information.
<Configuration of Second Embodiment>

8 is a functional block diagram showing an example of the surface state information acquisition device of this embodiment. As shown in the figure, the surface state information acquisition device 0800 of this embodiment has a radiation receiving unit 0801, a p-polarized radiance acquisition unit 0802, an s-polarized radiance acquisition unit 0803, a ps ratio calculation unit 0804, a surface roughness information acquisition unit 0805, and an alloying progress information acquisition unit 0806. The configurations other than the alloying progress information acquisition unit are the same as the respective configurations in the surface state information acquisition device of embodiment 1, so description thereof will be omitted.
<Embodiment 2: Measurement target>

The object to be measured in this embodiment is an alloy. For example, when a zinc-plated steel sheet is heated in an alloying furnace, a plating layer is formed on its surface. This plating layer is an Fe-Zn alloy, which is not only corrosion-resistant but also has excellent paintability, paint adhesion, and weldability, and is therefore widely used as steel sheet for automobiles.

On the other hand, if alloying progresses too far, the Γ phase develops at the interface between the base steel and the plating layer. This structure is hard and brittle, so if it grows abnormally, the plating layer can break into powder during press processing. To prevent such problems from occurring, it is important in the manufacturing process to understand the degree of alloying of the object being measured.

The alloy in this embodiment is not limited to the above-mentioned Fe-Zn alloy, and may be, for example, steel, Krupp steel, chromium molybdenum steel, manganese molybdenum steel, stainless steel, maraging steel, silicon iron, brass, bronze, copper, duralumin, nichrome, magnesium alloy, titanium alloy, and various other alloys.
<Embodiment 2: Alloying progress information acquisition unit>

The alloying progress information acquisition unit 0806 is configured to acquire alloying progress information based on the acquired surface roughness information, which is information indicating the progress of alloying of the measurement object. For example, the surface of a galvanized steel sheet becomes rough as alloying progresses. Therefore, the relationship between the alloying progress information and the surface roughness information of the measurement object is acquired in advance by an experiment. Then, at the time of measurement, the alloying progress information can be acquired by applying the surface roughness information acquired based on the measured p-polarized radiance and s-polarized radiance to the relationship between the alloying progress information and the surface roughness information of the measurement object acquired in advance. The experiment for acquiring the relationship between the alloying progress information and the surface roughness information is performed by measuring the surface roughness information of the measurement object using a surface state information measuring device while measuring the alloying progress information of the measurement object, and retaining the respective measured values in association with each other. By performing such an experiment on multiple types of samples that can be the measurement object in multiple steps, the relationship between the surface roughness information and the alloying progress information of the measurement object can be retained. The measurement of the alloying progress information can be performed, for example, based on the fluorescent X-ray intensity of the measurement object. It is also possible to perform the measurement by other methods.
<Embodiment 2: Hardware>

The surface condition information acquisition device of this embodiment can be realized in accordance with the hardware configuration that realizes the surface condition information acquisition device of embodiment 1, and can further store an alloying progress information acquisition program and data indicating the relationship between surface roughness information and alloying progress information in the non-volatile memory, and can execute these programs as appropriate.
<Processing flow of embodiment 2>

9 is a flow diagram showing an example of the process flow of the surface state information acquisition device of this embodiment. First, radiation is received (0901: radiation receiving step). P-polarized radiance is acquired from the received radiation (0902: p-polarized radiance acquisition step). Then, s-polarized radiance is acquired from the received radiation (0903: s-polarized radiance acquisition step). Then, a ps ratio, which is the ratio between the acquired p-polarized radiance and the s-polarized radiance, is calculated (0904: ps ratio calculation step). Then, based on the acquired ps ratio and ps ratio/surface roughness correlation information acquired in advance for the measurement object, surface roughness information, which is information indicating the surface roughness of the measurement object, is acquired (0905: surface roughness information acquisition step). Then, based on the acquired surface roughness information, alloying progress information is acquired as information indicating the progress of alloying of the measurement object (0906: alloying progress information acquisition step).
<Effects of Second Embodiment>

According to the surface condition information acquisition device of this embodiment, progress information that indicates the progress of alloying of the alloy, which is the measurement object, can be acquired based on surface roughness information.
<Embodiment 3>
<Overview of Third Embodiment>

The surface condition information acquisition device of this embodiment is based on the surface condition information acquisition device of embodiment 1 or embodiment 2, and is characterized by storing ps ratio/surface roughness correlation information at a plurality of angles of incidence acquired in advance. In addition to being able to increase measurement accuracy by acquiring surface roughness information from different angles for one measurement spot, since the appropriate ps radiance curve differs depending on the type of material to be measured, by selecting the optimal angle, good measurement can be performed even if the type of material changes.
<Configuration of Third Embodiment>

10 is a functional block diagram showing an example of the surface state information acquisition device of this embodiment. As shown in the figure, the surface state information acquisition device 1000 of this embodiment has a radiation receiving unit 1001, a p-polarized radiance acquisition unit 1002, an s-polarized radiance acquisition unit 1003, a ps ratio calculation unit 1004, a surface roughness information acquisition unit 1005, an alloying progress information acquisition unit 1006, and an angle change unit 1007, and the surface roughness information acquisition unit has an incident angle-specific surface roughness information acquisition means 1008. The other configurations of the surface roughness information acquisition unit having the angle change unit and the incident angle-specific surface roughness information acquisition means are similar to the respective configurations in the surface state information acquisition device of embodiment 1 or embodiment 2, so description will be omitted.
<Embodiment 3 Angle change unit>

The angle change unit 1007 is configured to be able to change the angle of incidence at which the radiation receiving unit focuses on the measurement spot. For example, the angle of incidence can be made changeable by providing a mechanism for changing the position or attitude of the radiation receiving unit that focuses on the measurement spot. Alternatively, a similar function can be achieved by providing multiple radiation receiving units that focus on the measurement spot at different angles of incidence and changing the radiation receiving unit used for measurement.
Third embodiment: ps ratio/surface roughness correlation information

The ps ratio-surface roughness correlation information previously acquired for the measurement object is held for a plurality of angles of incidence.
<Embodiment 3 Surface roughness information acquisition means by incident angle>

The incident angle-specific surface roughness information acquiring means 1008 is configured to acquire incident angle-specific surface roughness information, which is information indicating the surface roughness of the measurement object for each of a plurality of angles. For example, for one measurement spot, surface roughness information based on each incident angle can be acquired by measuring at different incident angles. It is also possible to configure the means 1008 to take the difference between the surface roughness information for each incident angle to verify the accuracy of the measurement result, or to perform the measurement again if the difference is greater than a predetermined value. It is also possible to configure the means 1008 to acquire the average of the surface roughness information for each incident angle as the surface roughness information.
Third Embodiment Hardware

The surface condition information acquisition device of this embodiment can be realized in accordance with the hardware configuration that realizes the surface condition information acquisition device of embodiment 1 or embodiment 2, and further has an angle changing program and a sub-program for acquiring surface roughness information by incident angle in the non-volatile memory, and can store ps ratio/surface roughness correlation information for a plurality of incident angles and execute these programs appropriately.
<Processing flow of embodiment 3>

The processing flow of this embodiment is similar to the processing flow of embodiment 1 or embodiment 2, and the surface roughness information acquisition step has a surface roughness information acquisition sub-step that acquires surface roughness information by incident angle, which is information indicating the surface roughness of the object to be measured for each of a plurality of angles.
<Effects of Third Embodiment>

According to the surface roughness information acquisition device of this embodiment, measurements can be taken at different incidence angles to obtain surface roughness information based on each incidence angle, which contributes to improving the precision and accuracy of the measurement.
<Embodiment 4>
<Outline of Fourth Embodiment>

This embodiment relates to a surface condition information acquisition device that is based on any one of the first to third embodiments and can measure the temperature of a measurement spot from the acquired p-polarized radiance or the acquired s-polarized radiance.
<Embodiment 4: Configuration of a radiation thermometry device>

FIG. 11 is a conceptual diagram showing an example of the radiation temperature measuring device of this embodiment. As shown in the figure, the surface state information acquisition device 1100 of this embodiment has a radiation receiving unit 1101, a p-polarized radiance acquisition unit 1102, an s-polarized radiance acquisition unit 1103, a ps ratio calculation unit 1104, a surface roughness information acquisition unit 1105, and an alloying progress information acquisition unit 1106, and further has a p-polarized blackbody temperature calibration curve information storage unit 1107 and a temperature acquisition unit 1108. The configurations other than the p-polarized blackbody temperature calibration curve information storage unit and the temperature acquisition unit are the same as the configurations in the surface state information acquisition devices of embodiments 1 to 3, so the description will be omitted. In addition, this figure does not show the angle change unit and the incident angle-specific surface roughness information acquisition means described in the previous embodiment, but it may be configured to have these units and means.
(Embodiment 4: p-polarized blackbody temperature calibration curve information storage unit)

The p-polarized blackbody temperature calibration curve information storage unit 1107 has p-polarized blackbody temperature calibration curve information indicating the relationship between p-polarized radiance and the surface temperature of a blackbody. By having the p-polarized blackbody temperature calibration curve information, it is possible to obtain the temperature of the measurement spot based on the p-polarized radiance obtained by the temperature acquisition unit described later.
(Embodiment 4: Temperature Acquisition Unit)

The temperature acquisition unit 1108 is configured to acquire the temperature of the measurement spot from the acquired p-polarized radiance and the stored p-polarized blackbody temperature calibration curve information. The p-polarized radiance acquired by the p-polarized radiance acquisition unit is applied to the calibration curve or relational expression indicated by the stored p-polarized blackbody temperature calibration curve information, thereby acquiring the temperature of the measurement spot corresponding to the p-polarized radiance.
(Embodiment 4: s-polarized blackbody temperature calibration curve information storage unit)

Although not shown in FIG. 11, the device can be configured to have an s-polarized blackbody temperature calibration curve information storage unit in addition to or instead of the p-polarized blackbody temperature calibration curve information storage unit. The s-polarized blackbody temperature calibration curve information storage unit is configured to have s-polarized blackbody temperature calibration curve information that indicates the relationship between s-polarized radiance and the surface temperature of the blackbody, and the temperature acquisition unit described above can be configured to acquire the temperature of the measurement spot from the stored s-polarized blackbody temperature calibration curve information and the s-polarized radiance acquired by the p-polarized radiance acquisition unit.

As shown in Fig. 4, the p-polarized emissivity _εp is larger than the s-polarized emissivity _εs . In other words, the value is close to the emissivity of a black body, so it is preferable to obtain the temperature using p-polarized radiance, since it is possible to obtain the temperature with relatively higher accuracy than when using s-polarized radiance.
(Embodiment 4: Hardware)

The surface condition information acquisition device of this embodiment can be realized in accordance with the hardware configuration realizing the surface condition information acquisition device of embodiments 1 to 3, and can be realized by further having a temperature acquisition program in the non-volatile memory, storing p-polarized blackbody temperature calibration curve information and/or s-polarized blackbody temperature calibration curve information, and executing these programs appropriately.
<Processing flow of embodiment 4>

The processing flow of this embodiment is similar to the processing flow of embodiments 1 to 3, and further includes a temperature acquisition step of acquiring the temperature of the measurement spot from the acquired p-polarized radiance and the retained p-polarized blackbody temperature calibration curve information and/or a temperature acquisition step of acquiring the temperature of the measurement spot from the acquired s-polarized radiance and the retained s-polarized blackbody temperature calibration curve information.
(Effects of the fourth embodiment)

According to this embodiment, it is possible to provide a surface condition information acquisition device that can also acquire the temperature of a measurement spot using p-polarized radiance or s-polarized radiance for acquiring surface roughness information.
<Embodiment 5>
<Outline of Fifth Embodiment>

This embodiment is based on any one of the first to fourth embodiments and is applied as a radiation temperature measuring device by utilizing multiple reflection between hemispherical mirrors.
<Configuration of Radiation Thermometry Device in Fifth Embodiment>

Figure 12 is a conceptual diagram showing an example of a radiation thermometry device of this embodiment. Figure 12(a) is a view from above, and Figure 12(b) is a view from the side. The radiation thermometry device of this embodiment is composed of a measurement object 1201, a first mirror 1202, a second mirror 1203, and a radiation light receiving unit 1205. Although not shown, this radiation thermometry device also has each of the components such as the p-polarized radiance acquisition unit and the s-polarized radiance acquisition unit described in embodiments 1 to 4.

The radiation receiving unit 1205 measures the radiance _L2, which is the apparent emissivity of the measurement sample increased by the light multiple-reflected between the first mirror and the second mirror, through the hole 1207. The radiation receiving unit is composed of an infrared light detection element such as a thermopile, and an optical system such as a lens that focuses the infrared light emitted from the target on the infrared light detection element. In addition, a shutter 1206 that can stop the reflection of the second mirror is provided in front of the second mirror. This shutter covers the second mirror when the reflection of the second mirror is stopped, and is composed of a surface that reflects light as little as possible, such as a black body surface, facing the measurement spot. The radiation receiving unit measures the radiance _L1 when the reflection of the second mirror is stopped by the shutter. In addition, the radiance of p-polarized light and s-polarized light can be obtained by placing a chopper equipped with a non-polarizing element and p-polarizing and s-polarizing elements as shown in Figure 7(c) on the radiation thermometer when the reflection of the second mirror is stopped by the shutter, and receiving light through each of the polarizing elements, thereby obtaining the p-polarized radiance, s-polarized radiance, and non-polarized radiance.
<Embodiment 4: Measurement principle of radiation thermometry>

The radiation thermometry device of this embodiment can measure temperature based on the following measurement principle. In summary, the emissivity of the measurement target is estimated based on the ratio (hereinafter referred to as radiance ratio) R _L = L ₂ /L ₁ between the radiance L ₂ emitted from the measurement spot and measured after multiple reflections between the first mirror and the second mirror and the radiance L ₁ measured without multiple reflections, and the reflection distribution of the measurement spot, and the temperature of the measurement spot is obtained from the estimated emissivity. The radiance L ₁ can be measured by stopping the reflection of the second mirror by operating the shutter, and the radiance L ₂ can be measured by reflecting the second mirror without operating the shutter.

First, the above _L1 and _L2 can be expressed by the following formula 5. ε _λ is the emissivity at wavelength λ, which corresponds to the emissivity ε _θ in the angle θ direction of the temperature measurement object. ε _eff is the emissivity that appears to be increased due to multiple reflections. Furthermore, L _b , _λ (T) is the radiance at wavelength λ of an ideal black body (emissivity ε = 1) at temperature T.

Here, if the surface of the measurement object is a perfectly mirror-like reflecting surface, in theory, multiple reflections will be repeated forever between the first mirror and the second mirror. However, in reality, the radiant flux will diffuse to the outside of one of the mirrors every time it is reflected by the measurement object. Therefore, the radiant flux passing through the hole when reflected by the first mirror on the radiation receiving unit side can be considered as the sum of n finite round trips between the second mirror and the first mirror. If the reflectances of the first mirror and the second mirror are ρ and the reflection distribution coefficient, which is a coefficient representing the reflection distribution of the measurement surface of the measurement object, is γ, _L2 can be expressed as in the following Equation 6.

Therefore, the radiance ratio R _L can be expressed as Equation 7.

Then, by setting α=1/ργ−1, the relationship of Equation 8 is obtained.

In this way, it is understood that the emissivity ε _θ of the measurement spot in the direction of the angle θ can be obtained by determining the parameter α. If ε _θ is obtained, the temperature of the measurement spot can be calculated more accurately by correcting the emissivity.

Here, an example of a means for measuring the reflection distribution coefficient γ is shown in FIG. 13. As shown in FIG. 13(a), a laser light source 1302 is provided for irradiating a laser light from a vertical direction to a measurement object 1301. In addition, a plurality of light receiving elements 1303 for measuring the intensity of the irradiated laser light diffusely reflected by the measurement object at a plurality of diffusion angles (θ1, θ2, θ3) as shown in FIG. 13(b) are arranged in a circumferential manner. These light receiving elements measure the diffuse reflection light intensity (I _θ1 , I _θ2 , ...) at each diffusion angle as shown in FIG. 13(b). It is assumed that the diffuse reflection of the irradiated laser light occurs evenly in all directions (360°), and it is sufficient to measure the diffuse reflection light intensity with the light receiving elements arranged in a circumferential manner based on this assumption. In addition, the distances from the incident point of the laser light to the plurality of light receiving elements are not necessarily equal, but by configuring the difference in distance to be within a few millimeters to a few centimeters, even if a difference in distance occurs, it is not necessary to consider the attenuation of the diffuse reflection light intensity due to distance.

A beam splitter 1304 is placed on the trajectory of the laser light irradiated from the laser light source to the object to be measured, a light receiving element 1305 is placed in the direction of the spectrum, and the reflected light intensity _Iθ0 of the laser light specularly reflected by the object to be measured as shown in Fig. 13(b) is measured by this light receiving element 1305. Using the means configured in this way, a reflection distribution coefficient γ is obtained from the diffuse reflected light intensities ( _Iθ1 and _Iθ2 ) at any two arbitrary angles (for example, _θ1 and _θ2 ) of the obtained diffuse reflected light intensities by the following formula 9.
<Formula 9>

The reflection distribution coefficient γ may be obtained by the following equation 10 using the reflected light intensity _Iθ0 of the laser light specularly reflected by the measurement object described above, instead of equation 9.
<Formula 10>

Here, the reflection distribution coefficient γ in the measurement principle described above is replaced with the surface roughness information described in the first embodiment and the like. The surface roughness information can be expressed as the polarized emissivity ratio ε _s /ε _p or dep = (ε _p -ε _s ) / (ε _p +ε _s ), which is the ps ratio, as shown in FIG. 4. Therefore, the relationship between the reflection distribution coefficient γ and the parameter α in the measurement principle is replaced with the relationship between the ps ratio and the parameter α, and a relational expression between the ps ratio and the parameter α as shown in FIG. 14 is obtained by performing an experiment in advance. The parameter α can be obtained by applying the ps ratio at the time of measurement to this relational expression. Then, the emissivity ε _θ of the temperature measurement target is obtained by substituting the obtained α and the radiance ratio R _L obtained from the measurement into Equation 8.

The radiance _L1 obtained by receiving light from the measurement spot without multiple reflection is shown in Equation 5. The emissivity ε _θ of the measurement spot corresponds to ε _λ in Equation 5. The conversion from radiance to temperature is based on a calibration curve showing the relationship between radiance and the temperature of a black body stored in advance. Since the emissivity of the measurement spot is smaller than the emissivity of a black body, which is 1.0, the radiance from the measurement spot is smaller than that of a black body at the same temperature. Therefore, if the radiance _L1 is directly converted to temperature based on the calibration curve of the black body, it will be converted to a temperature lower than the actual temperature. Therefore, the radiance _L1 obtained based on Equation 5 is divided by ε _θ , and the temperature is converted using this value. By performing this correction, it is possible to accurately measure the temperature according to the emissivity of the measurement spot.
(Effects of the Fifth Embodiment)

According to this embodiment, the emissivity can be calculated using surface roughness information based on the ps ratio, and temperature measurement can be performed with emissivity correction.

0100 Surface state information acquisition device 0101 Synchrotron radiation receiver 0102 P-polarized radiance acquisition unit 0103 S-polarized radiance acquisition unit 0104 PS ratio calculation unit 0105 Surface roughness information acquisition unit

Claims (4)

a radiation receiving unit that receives radiation from a predetermined measurement spot on the measurement object;
a p-polarized radiance acquisition unit that acquires p-polarized radiance from the emitted light receiving unit;
an s-polarized radiance acquisition unit that acquires s-polarized radiance from the radiation receiving unit;
a ps ratio calculation unit that calculates a ps ratio between the acquired p-polarized radiance and s-polarized radiance;
a surface roughness information acquiring unit that acquires surface roughness information that is information indicating the surface roughness of the measurement object based on the acquired p-s ratio and p-s ratio/surface roughness correlation information previously acquired for the measurement object;
a p-polarized light blackbody temperature calibration curve information storage unit having p-polarized light blackbody temperature calibration curve information indicating a relationship between p-polarized light radiance and a surface temperature of a blackbody;
a temperature acquisition unit that acquires the temperature of the measurement spot from the acquired p-polarized radiance and stored p-polarized blackbody temperature calibration curve information;
an s-polarized blackbody temperature calibration curve information storage unit having s-polarized blackbody temperature calibration curve information indicating a relationship between s-polarized radiance and a surface temperature of a blackbody;
a temperature acquisition unit that acquires the temperature of the measurement spot from the acquired s-polarized radiance and stored s-polarized blackbody temperature calibration curve information;
An apparatus for acquiring surface condition information of a measurement object. The object to be measured is an alloy,
The surface condition information acquisition device according to claim 1 , further comprising an alloying progress information acquisition unit that acquires alloying progress information, which is information indicating the progress of alloying of the measurement object, based on the acquired surface roughness information. The radiation receiving unit further includes an angle changing unit capable of changing an incident angle at which the radiation receiving unit focuses onto a measurement spot,
The surface condition information acquisition device of claim 1 or claim 2, wherein the ps ratio/surface roughness correlation information acquired in advance for the object to be measured is held for a plurality of angles of incidence, and the surface roughness information acquisition unit has an incident angle-specific surface roughness information acquisition means for acquiring incident angle-specific surface roughness information which is information indicating the surface roughness of the object to be measured for each of the plurality of angles. a radiation receiving step of receiving radiation from a predetermined measurement spot on the measurement object;
A p-polarized radiance acquisition step of acquiring p-polarized radiance from the received radiation;
an s-polarized radiance acquisition step of acquiring s-polarized radiance from the received radiation;
a ps ratio calculation step of calculating a ps ratio between the acquired p-polarized radiance and s-polarized radiance;
a surface roughness information acquiring step of acquiring surface roughness information which is information indicating the surface roughness of the measurement object based on the acquired p-s ratio and p-s ratio/surface roughness correlation information previously acquired for the measurement object;
a p-polarized light blackbody temperature calibration curve information storage step having p-polarized light blackbody temperature calibration curve information indicating a relationship between p-polarized light radiance and a surface temperature of a blackbody;
a temperature acquisition step of acquiring a temperature of the measurement spot from the acquired p-polarized radiance and stored p-polarized blackbody temperature calibration curve information;
an s-polarized blackbody temperature calibration curve information storage step having s-polarized blackbody temperature calibration curve information indicating a relationship between s-polarized radiance and a surface temperature of a blackbody;
a temperature acquisition step of acquiring a temperature of the measurement spot from the acquired s-polarized radiance and stored s-polarized blackbody temperature calibration curve information;
A method for acquiring surface condition information of a measurement object comprising the steps of:

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