High-precision optical particle measuring device and particle measuring method using laser current scanning

Abstract

The present invention provides a particle measuring device and a particle measuring method, which utilize laser current scanning of a laser that irradiates electric current sequentially to measure the number of particles by size range with high accuracy. First, corresponding to a plurality of mutually different particle sizes, a laser with a minimum current capable of measuring particles above the corresponding size is irradiated into a particle measuring space for a certain period of time, and the scattered light is detected to measure the number of sizes of each particle. Then, the measured value is used to accurately calculate the number of particles belonging to each size range using an operation rule. At this time, the proportional relationship between the measured number of particles and the laser current is utilized. No other components such as a flow nozzle or a flat-top optical meter are used, so the research and development costs of the particle measuring device can be saved, and it can be used regardless of normal pressure (atmospheric pressure) or a vacuum environment. In addition, the accuracy is improved by upgrading the operation rule of the existing device.

Description

Technical Field

[0001] The present invention relates to a particle measuring device and a particle measuring method, and more specifically, by utilizing laser current scanning of a laser irradiating various currents required for measuring particles of various sizes, the number of particles can be measured with high accuracy and within a size range even without using additional parts such as a flow nozzle or a flat-top optical meter. Background Art

[0002] Generally speaking, for processes requiring high precision such as semiconductor processes or light emitting diode (LCD) processes, if contamination particles above a certain level are generated in a process chamber, serious product failures may result. Therefore, the processes are performed under strictly restricted conditions.

[0003] In order to manage contamination, it is necessary to measure the contamination particles inside the cavity. Through a contamination particle measurement method, the particle distribution state of a specific cavity can be measured in real time using an optical measurement device.

[0004] Optical particle measuring devices use the principle that the intensity of scattered light emitted when laser light hits particles varies according to their size.

[0005] The smaller the particle size, the smaller the intensity of scattered light, which can be calculated by Mie theory. The intensity of scattered light is proportional to the intensity of incident light, so in order to measure small particles, the intensity of incident light needs to be increased.

[0006] Therefore, in order to measure small-sized particles, it is necessary to focus the laser light.

[0007] Figure 1 The diagram shows how incident light (12) generated from a laser light source (11) is focused on a flow channel (15) through several optical components. Here, the flow channel (15) is a space where particles to be measured exist.

[0008] In order to measure the accurate particle size using Mie (light scattering) theory, the intensity of the incident light (Io) should be kept constant, referring to the following mathematical formula.

[0009] [Mathematical formula]

[0010]

[0011] Here, I scat refers to the intensity of scattered light, R refers to the distance from the point where the scattered light occurs to the detector, and σ′ scat It is a function of particle size.

[0012] At this time, the intensity of scattered light changes for particles of the same size depending on whether any position of the incident light to be focused passes through the particle.

[0013] The cross section (21) of the light is not uniform in the r-axis direction. Therefore, when the scattered light is changed according to the particle size, even if the same particles are measured, they can be identified as different sizes, and the optical particle measuring device cannot measure the accurate size.

[0014] To address the accuracy issues regarding particle size determination, the following techniques are currently used.

[0015] First, if Figure 2 As shown in the example, a method is used to make particles pass through a specific position of incident light using a flow nozzle. Figure 2 An example of a particle measuring device using a flow nozzle includes a 90 degree detector, a light scanner, a 90 degree optics, a light trap, a reflector, a laser beam, a laser diode and other light sources.

[0016] When this method is used, since only the particle passes through the designated position of the incident light, the intensity of the incident light is predetermined, and thus the accurate size can be measured.

[0017] Currently, most contamination particle counters use this method. However, this method can be used under normal pressure (atmospheric pressure), but it is difficult to use in processes that are sensitive to pressure changes, such as vacuum processes. In particular, it cannot be used in semiconductor industry sites due to the influence of process conditions.

[0018] Furthermore, it is necessary to incur additional costs for manufacturing the flow nozzle, and the flow nozzle may be clogged by particles, thereby making management difficult.

[0019] As another method, Figure 3 As an example, the "High-precision Real-time Fine Particle Size and Quantity Measurement Device" registered patent No. 10-1857950 discloses a technology that uses a flat-top (17) module to maintain uniform light intensity, thereby enabling more accurate particle size measurement.

[0020] That is, in order to solve the problem of dimensional measurement accuracy caused by changes in the intensity of incident light, registered patent No. 10-1857950 uses a method of making the intensity of the incident light (12) in the r-axis direction of the cross section (22) of light uniform.

[0021] When an optical device (lens) is constructed to make incident light uniform, the intensity of the incident light in the r-axis direction is made uniform, and the size of scattered light does not change when the particles pass through any position.

[0022] However, the particle measuring device applicable to this method has a very important optical meter structure and needs to use an aspherical optical meter, which increases the cost exponentially. The intensity of the focused light is weaker than that of ordinary focused light, and there is a problem that nanometer-sized particles cannot be measured.

[0023] Prior art literature

[0024] Patent Literature

[0025] (1) Korean registered patent No. 10-1857950 (Title: High-precision real-time fine particle size and quantity measurement device, publication date: 2018.01.02)

[0026] Summary of the invention

[0027] Technical problem to be solved by the invention

[0028] Therefore, the present invention has been developed to solve the above-mentioned problems, and its purpose is to provide a high-precision optical particle measuring device that uses laser current scanning of a laser irradiating various currents required for measuring particles of various sizes to measure the number of particles with high accuracy and within a size range.

[0029] Another object of the present invention is to provide a high-precision optical particle measurement method that uses laser current scanning to measure the number of particles with high accuracy and within a size range.

[0030] Technical solutions to solve problems

[0031] In order to achieve the above-mentioned purpose, the high-precision optical particle measuring device using laser current scanning of the present invention comprises: a light irradiation unit, which corresponds to a plurality of mutually different particle sizes (R1, R2, ..., Rm), and irradiates a laser with a minimum current that can only measure particles of the corresponding size or larger into a particle measuring space for a certain period of time; and a measuring unit, which detects light scattered from particles in the particle measuring space by the laser irradiated by the light irradiation unit, thereby measuring the number of particles according to their size. At this time, the measuring unit calculates the number of particles belonging to a specific interval using the number of particles measured by irradiating the respective lasers.

[0032] The light irradiation unit continuously irradiates laser light of minimum current corresponding to the different particle sizes.

[0033] The light irradiation unit irradiates laser beams corresponding to the different particle sizes in order from the smallest current.

[0034] The number of particles belonging to the specific interval is calculated by an algorithm using the proportional relationship between the number of measured particles and the irradiated laser current.

[0035] The measuring unit measures the number of particles in each size range according to the formula "ni = ni[P1] + ni[P2] +... + ni[Pk]".

[0036] Here, ni refers to the number of particles in the size range Ai (Ri ≤ Ai < R(i + 1)) to be calculated, Pk refers to the minimum laser current for measuring particles of size Rk, ni[Pk] refers to the number of particles in the size range Ai measured when irradiating laser with a current of Pk, and N[Pk] refers to the total number of particles measured when irradiating laser with a current of Pk.

[0037] And,

[0038] ni[Pk] = 0, (i < k),

[0039] ni[Pk] = ni[Pk], (i = k),

[0040] ni[Pk] = (Pi / Pk) × ni[Pi], (i > k).

[0041] Using an embodiment of the high-precision optical particle measurement method with laser current scanning of the present invention, the following steps are performed: First step, first corresponding to a plurality of mutually different particle sizes (R1, R2,..., Rm) respectively, the light irradiation unit irradiates laser with the minimum current capable of measuring particles of the corresponding size or above to the particle measurement space within a certain time; and second step, the measuring unit detects the light scattered by the particles in the particle measurement space, thereby measuring the number of particles.

[0042] And, the measuring unit calculates the number of particles belonging to the specific space using the number of particles measured through the first step and the second step.

[0043] Another embodiment of the high-precision optical particle measurement method with laser current scanning of the present invention includes the following steps: Input step, input the measured values of the number of particles measured corresponding to a plurality of mutually different particle sizes (R1, R2,..., Rm) respectively, where the measured values of the number of particles refer to the number of particles measured by irradiating laser with the minimum current capable of measuring particles of the corresponding size or above to the particle measurement space within a certain time and detecting the light scattered by the particles in the particle measurement space; and calculation step, calculating the number of particles belonging to the specific interval using the input measured values of the number of particles.

[0044] Here, the calculation step measures the number of particles in each size range according to the formula "ni = ni[P1] + ni[P2] +... + ni[Pk]".

[0045] At this time, ni refers to the number of particles in the size range Ai (Ri ≤ Ai < R(i+1)) to be calculated, Pk refers to the minimum laser current for measuring particles of size Rk, ni[Pk] refers to the number of particles of Ai in the size range measured when laser with a current of Pk is irradiated, and N[Pk] refers to the total number of particles measured when laser with a current of Pk is irradiated.

[0046] And, ni[Pk] = 0, (i < k),

[0047] ni[Pk] = ni[Pk], (i = k),

[0048] ni[Pk] = (Pi / Pk) × ni[Pi], (i > k).

[0049] Effects of the Invention

[0050] According to the present invention, by laser current scanning that sequentially irradiates lasers with currents required for measuring particles of each size, the number of particles is measured with high accuracy and by size range.

[0051] Since no additional components such as a flow nozzle or a flat-top optical meter are used, thus, the development cost of the particle measuring device is saved, and it can be used regardless of the normal pressure (atmospheric pressure) or vacuum environment.

[0052] Develop a particle measuring device that uses algorithms to improve accuracy, and improve the accuracy by upgrading the algorithms of the existing device. Description of the Drawings

[0053] Figure 1 An example of measuring particles by using the focusing of light;

[0054] Figure 2 An example of using a flow nozzle in particle measurement;

[0055] Figure 3 An example of a method for uniformly manufacturing the intensity of light in the r direction;

[0056] Figure 4 An embodiment of the high-precision optical particle measuring device of the present invention;

[0057] Figure 5 An example of explaining lasers with different currents according to particle size;

[0058] Figure 6This is an embodiment of the high-precision optical particle measurement method of the present invention;

[0059] Figure 7 To illustrate the example of sequential irradiation starting from the laser with the lowest current;

[0060] Figure 8 Another embodiment of the high-precision optical particle measurement method of the present invention;

[0061] Fig. 9 This is an example showing the relationship between the measured number of particles and the laser current.

[0062] Description of Reference Numerals

[0063] 30: Particles

[0064] 40: Particle measurement space

[0065] 100: Particle measurement device

[0066] 110:Light irradiation part

[0067] 120: Measurement Department Specific embodiments

[0068] The present invention is subject to various changes and has various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, the present invention is not limited to a specific implementation form, and is understood to include changes, equivalents, and substitutes included in the concept and technical scope of the present invention.

[0069] When describing the present invention, if it is judged that a specific description of a related known technology obscures the gist of the present invention, the specific description will be omitted.

[0070] The terms used in this application are used to describe specific embodiments and are not intended to limit the present invention. Singular expressions also include plural expressions unless otherwise specified in the text.

[0071] In the present application, terms such as "including" or "having" refer to the existence of features, numbers, steps, actions, constituent elements, parts or features, numbers, steps, actions, constituent elements, and combinations of parts recorded in the specification, and are understood not to exclude in advance the existence or addition of one or more other features or numbers, steps, actions, constituent elements, parts or one or more other features or numbers, steps, actions, constituent elements, and combinations of parts.

[0072] The terms "first" and "second" are used to describe various components, but the components are not limited by the terms. The terms are used to distinguish one component from other components.

[0073] Reference Figure 4 The high-precision optical particle measuring device 100 using laser current scanning of the present invention includes: a light irradiation unit 110, which irradiates laser light to the particle measuring space 40 with two or more currents (powers) of different sizes; and a measuring unit 120, which detects light scattered from the particles 30 in the particle measuring space 40 by the laser irradiated by the light irradiation unit 110, and measures the number of particles.

[0074] The current of the laser beam irradiated from the light irradiation unit 110 is set corresponding to a plurality of mutually different particle sizes (R1, R2, . . . , Rm), and the minimum current of particles having each size or larger is measured.

[0075] That is, in order to measure particles of smaller size, a larger laser current is required, and in order to measure particles of larger size, a smaller laser current is required. As a specific example, when the minimum laser current for measuring particles with a diameter of more than 500nm is 100W, the minimum laser current for measuring particles with a diameter of more than 700nm is 80W, which is sufficient.

[0076] A plurality of mutually different particle sizes (R1, R2, . . . , Rm) corresponding to the currents of the respective lasers are the lower limit of the size range in which the number of particles is to be measured.

[0077] like Figure 5 As shown in the example, it is assumed that the minimum laser current required to measure particles of size R1 is P1, and the minimum laser current required to measure particles of size R2 is P2. Through this formula, it is explained that the minimum laser current required to measure particles of size Rm is Pm.

[0078] Here, the larger the subscript number of R is, the larger the particle size is. Therefore, the larger the subscript number of P is, the smaller the laser current is.

[0079] The light irradiation unit 110 corresponds to different particle sizes, and irradiates the particle measurement space with the laser of the minimum current that can measure particles of the corresponding size or larger in a certain period of time. The certain time of irradiating the laser of each current is set differently according to needs, and is not specially set. For example, the laser of each current is irradiated every ten seconds.

[0080] The light irradiation unit 110 continuously irradiates laser beams of currents corresponding to different particle sizes.

[0081] Furthermore, when the light irradiation unit 110 irradiates laser beams of currents corresponding to different particle sizes, the laser beams are irradiated in order from the current with the smallest current. Figure 5 In the example shown, Pm to P1 are irradiated in sequence.

[0082] Then, the measuring unit 120 detects light scattered from particles existing in the particle measuring space by the laser light irradiated by the light irradiation unit 110 , thereby measuring the number of particles according to their sizes.

[0083] The measurement unit 120 has different configurations for calculating the size range according to the number of particles.

[0084] In particular, the measuring unit 120 calculates the number of particles belonging to a range between two adjacent sizes of mutually different particle sizes using the number of particles measured by each laser irradiation.

[0085] For example, when the size range calculated by the measuring unit 120 according to the number of particles is called Ai, the size Ri of each particle at least includes 'Ri≤Ai <R(i+1))'。

[0086] In the above, referring to the example assuming that the minimum laser current for measuring particles with a diameter greater than 500nm is 100W, and the minimum laser current for measuring particles with a diameter greater than 700nm is 80W, the measuring unit 120 can calculate the number of particles with a size greater than 500nm and less than 700nm, and greater than 700nm.

[0087] The number of particles measured by irradiation with a laser current of 80W is the number of particles with a diameter exceeding 700nm, and the number of particles measured by irradiation with a laser current of 100W is the number of particles with a diameter exceeding 500nm. Therefore, the number of particles between 500nm and 700nm should be reasonably calculated using this information.

[0088] For this reason, the method has a different structure. As an example, the number of particles belonging to each interval is calculated by an algorithm using a proportional relationship between the number of particles measured and the irradiated laser current.

[0089] Fig. 9 This is an example of a graph showing the relationship between the number of particles measured and the laser current. The particle size is the result of an experiment in which the number of particles of 500 nm and 700 nm was measured while changing the laser current. As shown in this experimental graph, the number of particles measured is proportional to the laser current.

[0090] Using the example described above, a method of calculating the number of particles belonging to each size range is studied.

[0091] Scattering of particles occurs only when the intensity of incident light exceeds a certain value and the scattered light reaches a level that can be measured by the measuring unit 120. Assume that the minimum laser current for measuring particles with a diameter exceeding 500nm is 100W, and the minimum laser current for measuring particles with a diameter exceeding 700nm is 80W.

[0092] In order to measure particles of any size, the minimum current required is the laser current that produces detectable scattered light. Therefore, in the example described above, when a laser with a current of 80W is irradiated, even if particles with a diameter of less than 700nm produce scattered light, it will be at an undetectable level and will be drowned out by the noise.

[0093] First, the particles are measured for a certain period of time (e.g., 10 seconds) using a laser current of 80 W. The measured signals are generated in particles with a diameter exceeding 700 nm, and thus all the measured signals are counted as the number of particles exceeding 700 nm.

[0094] Currently, particles are measured within 10 seconds using a laser current of 100 W. Furthermore, since the measured signal is generated in particles with a diameter exceeding 500 nm, the measured signal is counted as the number of all particles exceeding 500 nm.

[0095] Here, the particle measurement process using the laser current of 100 W was performed immediately after the particle measurement process using the laser current of 80 W.

[0096] Assuming that a laser current of 80 W is used and the number of particles measured within 10 seconds is 1,000, it is assumed below that a laser current of 100 W is used and the number of particles measured within 10 seconds is 2,000.

[0097] When the number of particles measured in 10 seconds using 80W laser current is 1,000, the number of particles in the measured size range is 0 for particles in the size range of 500-700nm and 1,000 for particles larger than 700nm. Particles smaller than 700nm are not measured.

[0098] When a laser current of 100 W is used and the number of particles measured within 10 seconds is 2,000, the number of particles in the size range is calculated assuming that the number of measured particles is proportional to the laser current.

[0099] That is, the number of particles with a size exceeding 700 nm measured in 80 W is used.

[0100] The number of particles having a size exceeding 700 nm measured by laser light with a current of 100 W is calculated as shown in Mathematical Formula 1 below.

[0101] [Mathematical formula 1]

[0102] (100W / 80W)×1,000=1,250

[0103] Therefore, for the total number of particles with a size above 500 nm (2,000), the number of particles with a size in the range of 500 - 700 nm is calculated to be 750 (2,000 - 1,250), and the number of particles with a size above 700 nm is 1,250.

[0104] When sorting out the number of particles in the measured size range within a total of 20 seconds,

[0105] Number of particles with a size in the range of 500 - 700 nm: 750

[0106] Number of particles with a size above 700 nm: 2,250.

[0107] In the above example, when the laser current is adjusted twice, the size range of the particles is divided into two. Thus, when the laser current is adjusted n times, the size range of the particles is divided into m.

[0108] The specific embodiment in which the measuring unit 120 calculates the number of particles according to the size range is calculated by the following mathematical formula 2.

[0109] [Mathematical formula 2]

[0110] ni = ni[P1] + ni[P2] +... + ni[Pk],

[0111] Here, ni, as the value to be calculated, refers to the number of particles belonging to each size Ai (Ri ≤ Ai < R(i + 1)), Pk refers to the minimum laser current for measuring particles of size Rk, ni[Pk] refers to the number of particles in the size range Ai measured when irradiating with a laser having a current of Pk, and N[Pk] refers to the total number of particles measured when irradiating with a laser having a current of Pk.

[0112] And, ni[Pk] = 0, (i < k),

[0113] ni[Pk] = ni[Pk], (i = k),

[0114] ni[Pk] = (Pi / Pk) × ni[Pi], (i > k).

[0115] When applying the example of irradiating the 80W and 100W lasers as described for Mathematical formula 2, n1 (the number of particles belonging to the size range of 500 - 700 nm) and n2 (the number of particles with a size above 700 nm) are as shown in the following Mathematical formula 3.

[0116] [Mathematical formula 3]

[0117] n1 = n1[P1] + n1[P2]

[0118] n2 = n2[P1] + n2[P2]

[0119] Here, n1[P2]=0,

[0120] n2[P1]=(100 / 80)×1,000=1,250,

[0121] n1[P1]=2,000-1, 250=750(n1[P1]+n2[P1]=2,000),

[0122] n2[P2]=1,000 (n1[P2]+n2[P2]=1,000).

[0123] That is, as shown in the calculation formula above.

[0124] n1 (the number of particles in the size range of 500 to 700 nm) is 750, and n2 (the number of particles above 700 nm) is calculated to be 2,250.

[0125] Reference Figure 6 , describing a first embodiment of a high-precision optical particle measurement method using laser current scanning of the present invention.

[0126] The particle measuring method of the present invention is a method of measuring the number of particles in each size range using the particle measuring device 100 described above.

[0127] First, corresponding to a plurality of mutually different particle sizes (R1, R2, ..., Rm) respectively (S211, S215, S216), the light irradiation unit 110 irradiates a laser with a minimum current (Pi) for measuring particles above the corresponding size into a particle measuring space within a certain period of time (S212), and the measuring unit 120 detects light scattered from the particles in the particle measuring space and measures the number of particles (S213).

[0128] Step S212 and step S213 are performed for a certain period of time during which laser irradiation of each current is performed (S214).

[0129] In step S212 , the light irradiation unit 110 continuously irradiates laser beams having currents corresponding to different particle sizes, in descending order of current.

[0130] The measuring unit 120 executes steps S212 and S213 for all the different particle sizes (R1, R2, . . . , Rm), and then calculates the number of particles belonging to each size range using the number of particles measured by each laser irradiation (S217).

[0131] In this case, the measurement unit 120 distinguishes the number of particles and calculates a different size range.

[0132] For example, the number of particles measured by each laser irradiation is used to calculate the number of particles belonging to the interval between two adjacent sizes of each particle size (R1, R2, ..., Rm) associated with the laser irradiation. That is, the size range Ai calculated by the measuring unit 120 by distinguishing the number of particles includes at least one 'Ri≤Ai for each Ri <R(i+1))'。

[0133] In particular, the number of particles belonging to each interval is calculated by an algorithm using the proportional relationship between the number of measured particles and the irradiated laser current.

[0134] A general method for the measuring unit 120 to calculate the number of particles in each size range is described below based on the above-mentioned mathematical formula 2.

[0135] Next, a specific example of calculating the number of particles belonging to three particle size ranges will be described for particles having a size of 300 to 1,000 nm.

[0136] Referring to Table 1, ni is a value calculated as the number of particles belonging to each size range Ai, Pk refers to the minimum laser current for measuring particles of the minimum size in the size range Ai, ni[Pk] refers to the number of particles in the size range Ai measured when irradiated with a laser having a current of Pk, and N[Pk] refers to the total number of particles measured when irradiated with a laser having a current of Pk.

[0137] Reference Figure 7 and Figure 5 The laser is started from the smallest current, and thus, according to the start of measuring the number of particles, the laser is irradiated in sequence from the laser of the current P3 to the laser of the current P1.

[0138] Therefore, in Table 1, the order of irradiating laser light and measuring the number of particles is opposite to the sorting order (the order of rows).

[0139] The number of particles passing through the measuring unit 120 is measured while the laser beam of each current is irradiated.

[0140] Table 1

[0141]

[0142] The required value, i.e., the ni value, can be expressed as shown in the following mathematical formula 4.

[0143] [Formula 4]

[0144] n1=n1[P1]+n1[P2]+n1[P3]

[0145] n2=n2[P1]+n2[P2]+n2[P3]

[0146] n3 = n3[P1] + n3[P2] + n3[P3]

[0147] Here, each variable is transformed as shown in the following mathematical formula 5.

[0148] [Mathematical formula 5]

[0149] (1) ni[Pk] = 0, (i < k),

[0150] (2) ni[Pk] = ni[Pk], (i = k),

[0151] (3) ni[Pk] = (Pi / Pk) × ni[Pi]

[0152] That is, in the transformation formula (1) of mathematical formula 5, 'i < k' is the condition for irradiating a laser with a small current that cannot measure the smallest-sized particles belonging to the corresponding size range. Thus, it is shown that the particles in the corresponding size range cannot be measured. For example, n1[P2] = 0.

[0153] When using this transformation formula (1), the mathematical formula 4 is as shown in the following mathematical formula 6.

[0154] [Mathematical formula 6]

[0155] n1 = n1[P1] + 0 + 0

[0156] n2 = n2[P1] + n2[P2] + 0

[0157] n3 = n3[P1] + n3[P2] + n3[P3]

[0158] In the transformation formula (3) of mathematical formula 5, when the condition is 'i > k', the proportional formula related to the laser current is used to calculate the number of particles in the corresponding size range. When listing an example of the ni[Pk] value belonging to this condition, there is n3[P2].

[0159] When using the transformation formula (3) of mathematical formula 5, it is as shown in the following mathematical formula 7.

[0160] [Mathematical formula 7]

[0161] (A) n1 = n1[P1]

[0162] (B) n2 = (P1 / P2) × n2[P2] + n2[P2]

[0163] (C) n3 = (P1 / P3) × n3[P3] + (P2 / P3) × n3[P3] + n3[P3]

[0164] Thus, the basic formula for calculating the number of particles belonging to each size range Ai, that is, the ni value, is completed.

[0165] The above-mentioned mathematical formula 7 is a theoretical formula for obtaining the value of ni, and the value of ni[Pi] at each current needs to be obtained. For example, n1[P1] and n2[P2] are examples of such values, and such values ​​are obtained through actual measurement processes.

[0166] [Mathematical formula 8]

[0167] N[P1]=n1[P1]+n2[P1]+n3[P1]

[0168] N[P2]=n1[P2]+n2[P2]+n3[P2]

[0169] N[P3]=n1[P3]+n2[P3]+n3[P3]

[0170] In the above-mentioned mathematical formula 8, the value of N[Pk] refers to the total number of particles measured when the measurement is performed with the Pk current in actual measurement, and is the value of Pk that is independent of the size range Ai.

[0171] When the transformation formula (1) of the mathematical formula 5 is used, the mathematical formula 8 can be expressed as shown in the following mathematical formula 9.

[0172] [Mathematical formula 9]

[0173] N[P1]=n1[P1]+n2[P1]+n3[P1]

[0174] N[P2]=0+n2[P2]+n3[P2]

[0175] N[P3]=0+0+n3[P3]

[0176] Furthermore, when the transformation formula (3) is used, it is expressed by the following mathematical formula 10.

[0177] [Formula 10]

[0178] N[P1]=n1[P1]+(P1 / P2)×n2[P2]+(P1 / P3)×n3[P3]

[0179] N[P2]=n2[P2]+(P2 / P3)×n3[P3]

[0180] N[P3]=n3[P3]

[0181] At this time, N[P1], N[P2], and N[P3] are values ​​observed in all measurements.

[0182] Therefore, when using Mathematical Formula 7 and Mathematical Formula 10, n1, n2, and n3 are transformed as functions of N[P1], N[P2], and N[P3] as shown in the following Mathematical Formula 11.

[0183] [Mathematical formula 11]

[0184]

[0185]

[0186]

[0187] In addition, the second embodiment of the high-precision optical particle measurement method using laser current scanning of the present invention relates to a method in which a computer device accurately calculates the number of particles belonging to each size range based on the actual measured value of the number of particles.

[0188] Reference Figure 8 The second embodiment of the high-precision optical particle measurement method using laser current scanning of the present invention includes an input step (S231) and a calculation step (S232), which are executed in a computer device.

[0189] Here, the computer device refers to various types of devices, and for example, refers to another computer device that cooperates with the measuring unit 110 of the particle measuring device 100 of the present invention or the measuring unit 110 to receive digital data.

[0190] As an example of the latter, various user interface (UI: User Interface) screens are provided, and an administrator's computer device is taken as an example to provide various functions related to particle measurement according to user commands.

[0191] The input step (S231) inputs the actual values ​​of the number of particles measured corresponding to a plurality of mutually different particle sizes (R1, R2, . . . , Rm).

[0192] Here, the particle number measured value refers to the number of particles measured by detecting light scattered from particles in the particle measurement space when minimum current laser light for measuring particles of various sizes or larger is irradiated into the particle measurement space for a certain period of time.

[0193] The input of the measured value of the number of particles in the input step (S231) can be performed in real time or can be input in advance.

[0194] In addition, the calculation step (S232) uses the actual value of the number of particles input through the input step (S231) to measure the number of particles in each size range as shown in the description of the mathematical formula 2.

[0195] That is, when ni is the value to be calculated, which refers to the number of particles belonging to each size range Ai (Ri ≤ Ai < R(i+1)), Pk is the minimum laser current of the particles with the measured size Rk, ni[Pk] is the number of particles in the size range Ai measured when the laser with the current of Pk is irradiated, and N[Pk] is the total number of particles measured when the laser with the current of Pk is irradiated,

[0196] using ni = ni[P1] + ni[P2] +... + ni[Pk],

[0197] ni[Pk] = 0, (i < k),

[0198] ni[Pk] = ni[Pk], (i = k),

[0199] ni[Pk] = (Pi / Pk) × ni[Pi], (i > k),

[0200] the number of particles in each size range is measured by such relationships.

[0201] And, the calculation step (S232) measures the number of particles in the size range by each method described as needed, and repeated descriptions are omitted.

[0202] The second embodiment of the high-precision optical particle measurement method using laser current scanning according to the present invention is implemented by a code readable by a computer in a recording medium readable by the computer.

[0203] At this time, the recording medium readable by the computer includes all types of recording devices that store data read by the computer system.

[0204] For example, ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc., and the recording medium readable by the computer is dispersed in a computer system connected by a network, and the code read by the computer is stored and executed in a dispersed manner.

[0205] In summary, the present invention has been shown and described for specific preferred embodiments, but various modifications and changes to the present invention will be apparent to those skilled in the art within the scope of the technical features or the field of the present invention without departing from the scope of the claims.

Claims

1. A high-precision optical particle measurement device using laser current scanning, characterized in that: It includes: A light irradiation unit, corresponding to a plurality of mutually different particle sizes R1, R2,..., Rm respectively, and irradiating only the laser with the minimum current for measuring particles of a corresponding size or above to the particle measurement space within a certain time; A measurement unit that detects the light scattered by the particles in the particle measurement space from the laser irradiated through the light irradiation unit, and measures the number of particles according to the particle size; The measurement unit calculates the number of particles belonging to a specific interval by using the number of particles measured by each laser irradiation through the light irradiation unit; When ni refers to the number of particles in the size range Ai to be calculated, Ri ≤ Ai < R(i + 1), Pk refers to the minimum laser current for measuring particles of size Rk, and ni[Pk] refers to the number of particles in the size range Ai measured when the laser with a current of Pk is irradiated, The number of particles in the size range is measured according to the formula ni = ni[P1] + ni[P2] +... + ni[Pk], Here, ni[Pk] = 0, (i < k), ni[Pk] = ni[Pk], (i = k), ni[Pk] = (Pi / Pk) × ni[Pi], (i > k).

2. The high-precision optical particle measurement device using laser current scanning according to claim 1, characterized in that: The light irradiation unit continuously irradiates the laser with the minimum current corresponding to the mutually different particle sizes respectively.

3. The high-precision optical particle measurement device using laser current scanning according to claim 2, characterized in that: The light irradiation unit irradiates the lasers corresponding to the mutually different particle sizes in sequence from the one with a smaller current.

4. The high-precision optical particle measurement device using laser current scanning according to claim 1, characterized in that: The number of particles belonging to the specific interval is calculated by an algorithm using the proportional relationship between the number of measured particles and the irradiated laser current.

5. A high-precision optical particle measurement method using laser current scanning, characterized in that: Corresponding to a plurality of mutually different particle sizes R1, R2,..., Rm respectively, the following steps are performed: The first step, the light irradiation unit irradiates the laser with the minimum current for measuring particles of a corresponding size or above to the particle measurement space within a certain time; and The second step, the measurement unit detects the light scattered by the particles in the particle measurement space and measures the number of particles, The measurement unit calculates the number of particles belonging to a specific interval by using the number of particles measured through the first step and the second step; When ni refers to the number of particles in the size range Ai to be calculated, Ri ≤ Ai < R(i + 1), Pk refers to the minimum laser current for measuring particles of size Rk, and ni[Pk] refers to the number of particles in the size range Ai measured when the laser with a current of Pk is irradiated, The number of particles in each size range is measured according to the formula ni = ni[P1] + ni[P2] +... + ni[Pk], Here, ni[Pk] = 0, (i < k), ni[Pk] = ni[Pk], (i = k), ni[Pk] = (Pi / Pk) × ni[Pi], (i > k).

6. The high-precision optical particle measurement method using laser current scanning according to claim 5, characterized in that the laser irradiation in the first step is carried out starting from the one with a small current.

7. The high-precision optical particle measurement method using laser current scanning according to claim 5, characterized in that the number of particles belonging to the specific interval is calculated by an algorithm using the proportional relationship between the measured number of particles and the irradiated laser current.

8. A high-precision optical particle measurement method using laser current scanning, characterized in that it includes the following steps: An input step of respectively inputting the measured actual values of the number of particles corresponding to a plurality of mutually different particle sizes R1, R2,..., Rm. The measured actual values of the number of particles correspond to the plurality of mutually different particle sizes R1, R2,..., Rm. In a certain period of time, only the laser with the minimum current for measuring particles of a size equal to or larger than this size is irradiated onto the particle measurement space, and the light scattered by the particles from the particle measurement space is detected, and it is the number of particles to be measured; and A calculation step of calculating the number of particles belonging to a specific interval using the input measured actual values of the number of particles. In the calculation step, when ni refers to the number of particles in the size range Ai to be calculated, Ri ≤ Ai < R(i + 1), Pk refers to the minimum laser current for measuring particles of size Rk, and ni[Pk] refers to the number of particles in the size range Ai measured when the laser with a current of Pk is irradiated, the number of particles in each size range is measured according to the formula ni = ni[P1] + ni[P2] +... + ni[Pk]. ni[Pk] = 0, (i < k), ni[Pk] = ni[Pk], (i = k), ni[Pk] = (Pi / Pk) × ni[Pi], (i > k).

9. The high-precision optical particle measurement method using laser current scanning according to claim 8, characterized in that the input step and the calculation step are executed in the measurement unit described in claim 1, or in a computer device linked to the measurement unit.

10. A computer-readable recording medium, characterized in that it records a program for the computer to execute the high-precision optical particle measurement method using laser current scanning described in claim 8 or 9.

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