Optical foreign matter detection device using light scattering and image analysis

Abstract

In order to detect and analyze foreign matter contained in an object, the present invention provides an optical foreign matter detection device using light scattering and image analysis, comprising: an optical housing; a light irradiation unit attached to a lower portion of the optical housing and provided with a plurality of light sources for irradiating light to an object on a lower side, the light sources irradiating light at a predetermined amount of light such that light scattering can be generated according to a foreign object; an optical unit which is built in the upper part of the optical housing, captures an image of an object, and generates an image such that a foreign matter included in the object can be detected by light scattering of the foreign matter according to the light irradiated by the light source; and a user device for receiving, storing, reproducing and analyzing the image generated by the optical unit.

Description

Technical Field

[0001] The present invention relates to an optical foreign matter detection device using light scattering and image analysis, and more specifically, to an optical foreign matter detection device that detects and analyzes foreign matter by combining light scattering and image analysis, can confirm the size, shape, area, color, etc. of the foreign matter, has a high foreign matter detection and image analysis processing speed, and can detect foreign matter smaller than a pixel limit. Background Art

[0002] Generally speaking, with the increasing maturity of industry, the necessity to control foreign matter such as dust is increasing not only in office environments but also in production sites, and clean rooms are introduced to maintain the cleanliness of production sites to prevent foreign matter from having adverse effects on products.

[0003] Especially in high-tech industries involving nano-level high-precision manufacturing processes such as semiconductors or displays, even the smallest environmental conditions at the product manufacturing site can have a significant impact on product quality, so there is a trend towards increasingly stringent requirements for the cleanliness required in clean rooms.

[0004] Displays are used in mobile phones, tablets, monitors, home appliances, and automotive electronic devices. They are made of OCA films, polarizing films, and glass. If foreign matter of a certain size or larger is present in the films of these displays, it may cause pixel defects or lead to a decline in image quality. In addition, when foreign matter of a certain size or larger is contained in various films used for building windows or interior decoration, product defects will occur.

[0005] The conventional foreign matter detection device used to detect such foreign matter is a method of irradiating light to the sample and using the scattered light scattered by the foreign matter to measure the particle concentration. The scattered light is reflected directly or through a mirror and focused to the light receiving unit, and the amount of focused light is measured using an electrical signal to determine the number of foreign matter and the approximate size of the foreign matter. However, this type of foreign matter detection device has the problem of being unable to know the type, actual size, shape, major and minor axis length, area, color, etc. of the foreign matter.

[0006] In addition, optical microscopes can be used to detect foreign matter. Such devices can determine the actual size, shape, area, color, etc. of foreign matter, but it is difficult to detect foreign matter that is smaller than the pixel limit detectable by the image sensor connected to the optical microscope, and there is also the problem of long detection time.

[0007] The related prior art is Korean Patent Publication No. 10-2020-0052157 (2020.05.14), which includes: a stage for placing a sample; a low-magnification optical module, which shoots the sample and generates a low-magnification image; a high-magnification optical module, which shoots the sample and generates a high-magnification image, and is located opposite the low-magnification optical module with the sample as a reference; a driving module, which is used to move the high-magnification optical module; and a user device, which reproduces the low-magnification image and the high-magnification image, and discloses a digital microscope that changes the imaging area of ​​the high-magnification optical module by driving the driving module.

[0008] However, the prior art uses direct light, so it is not easy to detect small foreign objects. In addition, when there are multiple foreign objects, the detection takes a long time. It is necessary to use a low-magnification image to confirm the entire area of ​​the sample, and then move the high-magnification optical module to the area where the foreign objects are detected for precise observation. Therefore, the detection takes a long time, the operation is complicated, the equipment is large in size, and occupies a large space.

[0009] In addition, the prior art involves observing samples by placing them on a stage. Since the stage must always be equipped, the types, sizes or weights of samples that can be placed on the stage are limited, and there is a problem that the entire device is difficult to carry or move. Summary of the invention

[0010] 1. Technical issues to be resolved

[0011] The present invention is proposed to solve all the above problems, and its purpose is to provide an optical foreign matter detection device using light scattering and image analysis. By combining light scattering and image analysis, foreign matter can be quickly detected and analyzed, so that the actual size, shape, area and color of the foreign matter can be determined, and the path of the foreign matter entering can be determined, so that pollution control of the clean room can be achieved. Moreover, the processing speed of detecting foreign matter and analyzing images is fast, and foreign matter smaller than the pixel limit of the image sensor can be detected. It has high reliability by preventing errors in detecting foreign matter, can be placed on an object for use without a stage, and can be carried and easily moved to an object for use.

[0012] (II) Technical solution

[0013] In order to solve the above technical problems, the present invention provides an optical foreign matter detection device that uses light scattering and image analysis to detect and analyze foreign matter contained in an object, characterized in that the optical foreign matter detection device includes: an optical housing; a light irradiation unit, which is connected and installed at the lower part of the optical housing and is equipped with a plurality of light sources for irradiating light to the object on the lower side, the light source irradiating light with a predetermined light amount so that light scattering can be generated according to the foreign matter; an optical unit, which is built into the upper part of the optical housing, photographs the object and generates an image, so that the foreign matter contained in the object can be detected by using the light scattering of the foreign matter according to the light irradiated by the light source; and a user device for receiving, The image generated by the optical unit is stored, reproduced and analyzed. The user device calculates the magnified length value of the light-scattered standard particles in advance based on the light irradiation of the standard particle length values ​​of multiple standard particles, and creates a correlation chart between the standard particle length values ​​and the standard particle magnified length values, and saves it as a comparison standard for the foreign matter length value. The optical unit calculates the light-scattered foreign matter magnified length value in more than one direction for the foreign matter detected in the captured object image, and derives the corresponding standard particle length value based on the standard particle magnified length value that is the same as the foreign matter magnified length value to determine the length value of the foreign matter. The size, shape and area of ​​the foreign matter can be confirmed based on the foreign matter length value.

[0014] (III) Beneficial effects

[0015] The effects of the present invention are as follows: by combining light scattering and image analysis, foreign matter can be detected and analyzed, so that the actual size, shape, area and color of the foreign matter can be determined, and the path of entry of the foreign matter can be determined, so that pollution control of the clean room can be achieved, and the processing speed of detecting foreign matter and analyzing images is fast, and foreign matter smaller than the pixel limit of the image sensor can be detected. It has high reliability by preventing errors in detecting foreign matter, can be placed on an object for use without a stage, and can be carried and easily moved to an object for use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. 1 is a diagram showing a configuration of an optical foreign matter detection device according to an embodiment of the present invention. Figure 2a is a perspective view of an optical foreign matter detection device according to an embodiment of the present invention, Figure 2b is a bottom view of the optical foreign body detection device. Figure 2c This is a state diagram of the optical foreign matter detection device when it is in use. Figure 3a and Figure 3b FIG. 4 is a structural arrangement diagram of a light irradiation unit according to an embodiment of the present invention. Figure 4a is a graph schematically showing the correlation between the magnification of standard particle light scattering and the standard particle length value according to an embodiment of the present invention, Figure 4bSchematically shows a curve diagram showing the correlation between a standard particle magnified length value and a standard particle length value according to an embodiment of the present invention. Figure 5a to Figure 5d FIG. 4 is a diagram schematically showing a portion of a light scattering image according to the size and shape of foreign matter according to an embodiment of the present invention. Figure 6 is a flow chart showing a detection and analysis method of an optical foreign matter detection device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The optical foreign matter detection device 1 according to the present invention detects and analyzes foreign matter F contained in an object M such as a film, substrate, panel, or equipment by combining light scattering and image analysis, thereby being able to determine the size, shape, area, and color of the foreign matter F, and having a high foreign matter detection and image analysis processing speed, and being able to detect foreign matter smaller than a pixel boundary, and being able to be placed on the surface of the object M for use without a stage. Referring to FIG. 1 , it is configured to include: an optical housing 100, a light irradiation unit 200, an optical unit 300, and a user device 400, and may further include a foreign matter type analyzer (not shown).

[0018] refer to Figure 2a to Figure 2c According to an embodiment of the present invention, the optical housing 100 has an optical unit 300 built in the upper part, a light irradiation unit 200 connected and arranged in the lower part, a light scattering unit 110 is formed between the optical unit 300 and the light irradiation unit 200, and a handle 120 is formed on the outside. The optical housing 100 may be provided with an adjustment device (not shown) capable of adjusting the focal length of the optical unit 300.

[0019] The light scattering unit 110 provides a dark room inside so that light can be irradiated from the multiple light sources 210 of the light irradiation unit 200 on the lower side, scattered by the foreign matter F in the object M, and then received by the optical unit 300. For this purpose, the light scattering unit 110 is formed so that its diameter gradually decreases toward the upper side and converges to the light irradiation unit 200. When the user holds the handle 120 and places the optical housing 100 on the surface of the object M, a dark room is formed in the light scattering unit 110, and the surface of the object M equivalent to the inner diameter of the light irradiation unit 200 becomes the detection area.

[0020] refer to Figure 3a The light irradiation unit 200 is connected and installed at the lower part of the optical housing 100, and is provided with a plurality of light sources 210 to irradiate light from the side to the detection area of ​​the object M below. The light source 210 emits light with a predetermined predetermined light amount, so that light scattering occurs due to the foreign matter F contained in the object M. The optical unit 300 can generate an image containing scattered light, and the intensity of the scattered light is amplified due to the light scattering of the foreign matter F. The user device 400 detects and analyzes the foreign matter F in the object M.

[0021] As an embodiment, the light irradiation unit 200 is connected to the lower part of the light scattering unit 110, so that the annular light irradiation ring 220 protrudes outward, and a receiving space is formed inside the light irradiation ring 220, and a through hole with an inner diameter equal to the inner diameter of the lower part of the light scattering unit 110 is formed inside the light irradiation ring 220. A plurality of light sources 210 are arranged symmetrically with each other along the receiving space inside the light irradiation ring 220, and irradiate light with a predetermined light amount to the object M from multiple directions. The plurality of light sources 210 can be arranged symmetrically with each other in multiple directions, for example, 4 directions, 6 directions, 8 directions, 10 directions, 12 directions, 14 directions, 16 directions, etc., to irradiate light to the detection area of ​​the object M. A light diffusion plate (not shown) can be installed in front of the light source 210 to increase the uniformity of light amount distribution.

[0022] In addition, a fitting ring 230 may be combined at the lower portion of the light irradiation ring 220 to closely contact the surface of the object M, thereby preventing external light from entering and interfering with the interior of the optical housing 100 and providing a dark room.

[0023] For example, the fitting ring 230 may contain 30 to 50 wt % of polyphenylene sulfide resin, 15 to 25 wt % of SBR, 10 to 20 wt % of polyurethane resin, 10 to 20 wt % of polymethyl methacrylate, 5 to 10 wt % of 2-mercaptoadenine, and 1 to 5 wt % of a light absorber.

[0024] The polyphenylene sulfide resin is a semi-crystalline thermoplastic resin generated by the reaction of p-dichlorobenzene and sodium sulfide, which has excellent heat resistance, chemical resistance and weather resistance, good mechanical strength, and the addition amount is 30% to 50% by weight. The SBR is a styrene butadiene synthetic rubber, which has excellent strength and wear resistance, elasticity, and can provide friction for the contact surface. The addition amount is 15% to 25% by weight. The polyurethane resin has elasticity and provides strength to maintain hardness and prevent cracking, exhibits viscosity to increase adhesion, and has excellent pollution resistance. Especially when added with polyphenylene sulfide resin and SBR, because the physical properties such as elasticity, viscosity, toughness and weather resistance are improved, the modification effect is greatly improved. The addition amount is 10% to 20% by weight. The polymethyl methacrylate has excellent viscosity and adhesion and increases the binding force between particles. The addition amount is 10% to 20% by weight. The 2-mercaptoadenine is added in an amount of 5 to 10 weight percent, has needle-shaped fine crystals, forms a long-term stable and dense coating film, improves water tightness, inhibits cracking, helps to stably increase strength, and can prevent oxidation due to exposure to air and light. The light absorber is added in an amount of 1 to 5 weight percent to absorb light and prevent the occurrence of reflected light, so as to improve detection accuracy.

[0025] In addition, when light is irradiated only from one side of the detection area of ​​the object M, and the detection area of ​​the object M includes multiple foreign objects F, a shadow portion may appear on the back of one of the foreign objects F, and this shadow portion may make it difficult for other foreign objects F adjacent to it to be correctly detected. In the present invention, multiple light sources 210 are symmetrically arranged along the periphery of the detection area of ​​the object M installed in the optical housing 100, and a predetermined amount of light is irradiated to the detection area of ​​the optical housing 100 from multiple directions to prevent the detection of foreign objects F from being missed due to the shadow area, thereby improving the detection reliability. At this time, the light source 210 can be LED, laser, etc.

[0026] In addition, the light irradiation unit 200 preferably has a light irradiation angle of 1 to 60 degrees relative to the object M of the light source 210, and when the light irradiated from the light source 210 is reflected by the foreign matter F, light scattering in which the light diverges occurs, and the detection size that can be accepted by the image sensor of the optical unit 300 is increased, thereby increasing the detection capability, and the optical unit 300 can quickly detect and analyze the foreign matter F from the captured image, and can also detect foreign matter F that is smaller than the size that can be detected by the optical unit 300 or foreign matter F that cannot reflect light well. At this time, if the light irradiation angle exceeds 60 degrees, when the light is reflected by the foreign matter F, the effect of increasing the detection capability due to light scattering may be reduced, and if the light irradiation angle is less than 1 degree, when detecting the foreign matter F on the object M that is convex and curved upward or downward, the foreign matter F may be missed because a part of the object M is outside the light irradiation range.

[0027] As an example, see Figure 3b The light source 210 of the light irradiation unit 200 may include a plurality of lower light sources 211 arranged symmetrically to each other and a plurality of upper light sources 212 installed at a higher position than the lower light sources 211 and arranged symmetrically to each other. The lower light sources 211 and the upper light sources 212 are alternately arranged along the light irradiation unit 200 and irradiate light at different angles, the light irradiation angle of the lower light source 211 is a low angle of 1 to 30 degrees, and the light irradiation angle of the upper light source 212 is a high angle of 31 to 60 degrees, so that when a plurality of foreign objects F are adjacent to each other, the lower light sources 211 and the upper light sources 212 arranged alternately and symmetrically irradiate light at low and high angles, thereby preventing the error of failing to detect the scattered light of a small foreign object blocked by the scattered light of a large foreign object, thereby improving the detection reliability.

[0028] In addition, the multiple lower light sources 211 and the multiple upper light sources 212 can be alternately and symmetrically arranged in the accommodating space of a light irradiation ring 220, but the light irradiation ring 220 is formed to be divided into a lower light irradiation ring and an upper light irradiation ring above the lower light irradiation ring, and the multiple lower light sources 211 can be symmetrically arranged in the lower light irradiation ring, and the upper light sources 212 can be symmetrically arranged in the upper light irradiation ring.

[0029] According to the optical foreign matter detection device 1 of the present invention, a stage (not shown) can be additionally installed on the lower side of the light irradiation unit 200, the object M can be placed on the stage, and the foreign matter F can be detected using the optical unit 300, but it can also be used by easily moving the optical housing 100 without a stage and placing the optical housing 100 in the area where the foreign matter F is desired to be detected.

[0030] The optical unit 300 is built in the upper part of the optical housing 100 and includes an image sensor, captures the object M to generate an image, and detects foreign matter F included in the object M by utilizing light scattering of the foreign matter F due to light emitted from the plurality of light sources 210 .

[0031] Since the image captured by the optical unit 300 shows the light scattering that occurs when the light irradiated by the multiple light sources 210 is reflected by the foreign matter F, the detection capability can be improved by increasing the acceptable detection size of the image sensor of the optical unit 300, so that the foreign matter F can be easily and quickly detected and confirmed, and the foreign matter F whose size is smaller than the detectable size of the original optical unit 300 can be detected. For example, an image is composed of a plurality of very small quadrilaterals called pixels, and if the detectable pixel size of the image sensor of the optical unit 300 is 1 μm, the image sensor cannot detect foreign matter F smaller than 1 μm, but as described above, by using light scattering, the foreign matter F is scattered by light and enlarged from its original size, so that a small foreign matter F of about 1 / 5 of the detectable size of the image sensor of the original optical unit 300 can be detected.

[0032] The user device 400 may be an electronic device such as a computer, a laptop, a smart phone, a tablet computer or a PDA including a display screen and a communication module, and is used to receive, store, reproduce and analyze the image captured by the optical unit 300, and may be connected to the optical unit 300 via wired or wireless communication. The user device 400 is installed with a dedicated program capable of detecting and analyzing foreign matter F from an image.

[0033] The user device 400 includes a standard particle magnified length value calculation unit 410, a foreign matter length value comparison standard storage unit 420, a foreign matter detection unit 430, a foreign matter magnified length value calculation unit 440, a foreign matter length value judgment unit 450, a foreign matter analysis unit 460 and a judgment unit 480.

[0034] Standard particles are sold in the market by size and color. A plurality of standard particles are prepared in advance by size and placed on the surface of an object M. When the optical foreign matter detection device 1 of the present invention is used to irradiate the object M with a predetermined amount of light from a plurality of light sources 210, causing the standard particles to scatter light, and when the user device 400 receives an image taken by the optical unit 300, the standard particle magnified length value calculation unit 410 measures and calculates the light scattering standard particle magnified length value based on the length value of each standard particle in the image.

[0035] According to the experimental results of the inventors, there is a correlation that as the actual standard particle length value increases, the light scattering magnification of the standard particle decreases. The magnification at this time is "standard particle magnification length value / standard particle length value". The x-axis is the standard particle length value, and the y-axis is the magnification. Each value is input into a dedicated program, and the points corresponding to the input values ​​on the x-axis and y-axis are connected with trend lines using the dedicated program, and a trend line is created as shown below. Figure 4a The slope shown decreases sharply toward the lower right of the graph.

[0036] For example, when the standard particle length value is 0.4μm, the light scattering magnification of the standard particle is 3.5 times; when the standard particle length value is 1μm, the light scattering magnification of the standard particle is 3 times; when the standard particle length value is 10μm, the light scattering magnification of the standard particle is 2.5 times; when the standard particle length value is 100μm, the light scattering magnification of the standard particle is 2 times; when the standard particle length value is 1000μm, the light scattering magnification of the standard particle can be 1.2 times.

[0037] Therefore, in one embodiment, circular cross-section standard particles with standard particle length values ​​of 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 5μm, 10μm, 50μm, 100μm, 500μm, and 1000μm are prepared respectively, and the optical foreign matter detection device 1 of the present invention is used to capture the light scattering image of the standard particles by light irradiation, and then the standard particle magnified length value calculation unit 410 can calculate the light scattering magnified length value of the standard particles from the image. For example, when the standard particle length value is 0.4μm, the light scattering magnification of the standard particles detected in the image can be 3.5 times, so the standard particle magnified length value can be 1.4μm; when the standard particle length value is 1μm, the light scattering magnification of the standard particles detected in the image can be 3 times, so the standard particle magnified length value can be 3μm; when the standard particle length value is 10μm, the light scattering magnification of the standard particles detected in the image can be 2.5 times, so the standard particle magnified length value can be 25μm; when the standard particle length value is 100μm, the light scattering magnification of the standard particles detected in the image can be 2 times, so the standard particle magnified length value can be 200μm; when the standard particle length value is 1000μm, the light scattering magnification of the standard particles detected in the image can be 1.2 times, so the standard particle magnified length value can be 1200μm.

[0038] The foreign matter length value comparison standard storage unit 420 creates a graph of the correlation between the standard particle length value and the standard particle enlarged length value calculated by the standard particle enlarged length value calculation unit 410 as a comparison standard for the foreign matter length value and stores it.

[0039] For example, the x-axis is the standard particle length value, and the y-axis is the standard particle magnified length value. Enter each value into a dedicated program, and use the dedicated program to connect the points corresponding to the values ​​entered on the x-axis and y-axis with trend lines, and you will create something like Figure 4b The slope of the graph shown decreases sharply toward the upper right. At this time, if the intervals between the values ​​on the x-axis are reduced, and the standard particle enlarged length values ​​are calculated in advance for more standard particle length values ​​and a graph is drawn, the accuracy of the comparison standard can be further improved.

[0040] The foreign matter detection unit 430 detects the light-scattered foreign matter F from the image of the object M photographed and transmitted by the optical unit 300 by utilizing the light scattering of the foreign matter F by the side light irradiated by the light source 210, and may detect one or more light-scattered foreign matter F in the image.

[0041] The foreign matter magnified length value calculation unit 440 calculates the foreign matter magnified length value of the foreign matter F detected by the foreign matter detection unit 430, which is magnified due to light scattering. The foreign matter magnified length value calculation unit 440 can calculate the foreign matter magnified length values ​​in two or more directions respectively according to the light scattering shape of the foreign matter F. In this case, the foreign matter magnified lengths of the major axis and the minor axis of the foreign matter F can be calculated respectively.

[0042] The foreign body length value judgment unit 450 derives a standard particle length value corresponding to the standard particle magnified length value which is the same as the foreign body magnified length value from the comparison standard of the foreign body length value comparison standard storage unit 420, and judges this as the particle length value of the actual foreign body. The foreign body length value judgment unit 450 can derive the foreign body length values ​​of the foreign body F in multiple directions respectively, and as the number of foreign body length values ​​in multiple directions derived from one foreign body F increases, the accuracy of the size and shape of the foreign body F increases. However, for the tiny foreign body F in micron units, its shape is simple and not complicated, so as long as the length values ​​of the foreign body in several directions are derived, the actual shape of the foreign body can be easily confirmed by considering the light scattering shape together. For example, the shape of the foreign body can be derived from the foreign body length values ​​of the major axis and the minor axis of the foreign body F.

[0043] The foreign matter analyzing unit 460 analyzes the size and shape of the foreign matter F based on the length value of one or more foreign matters determined by the foreign matter length value determining unit 450, and calculates the area of ​​the foreign matter F. For example, if the foreign matter length values ​​obtained from multiple directions are approximately the same, the shape of the foreign matter F can be analyzed as a circle; if the foreign matter length values ​​obtained from multiple directions are different, the shape of the foreign matter F can be analyzed as a shape other than a circle; if the length of the major axis is much greater than the length of the minor axis, the shape of the foreign matter F can be analyzed as a fiber; if the size and shape of the foreign matter F are analyzed in this way, the area of ​​the foreign matter F can be easily calculated using a dedicated program.

[0044] The determination unit 480 determines whether the object M is contaminated based on the information analyzed by the foreign matter analysis unit 460. The determination of whether the object M is contaminated may vary depending on the type of the object M, the size, shape, and spacing of the foreign matter F. For example, a fibrous foreign matter F may have little effect on the contamination of a specific object M, and in this case, it may be determined to be a normal product.

[0045] Hereinafter, a process of detecting a foreign object F and analyzing the size or shape of the foreign object F using the optical foreign object detecting device 1 according to the present invention will be described using an embodiment.

[0046] For example, assume that when the standard particle length value is 0.4μm, the light scattering magnification of the standard particle is 3.5 times, when the standard particle length value is 1μm, the light scattering magnification of the standard particle is 3 times, when the standard particle length value is 10μm, the light scattering magnification of the standard particle is 2.5 times, when the standard particle length value is 100μm, the light scattering magnification of the standard particle is 2 times, and when the standard particle length value is 300μm, the light scattering magnification of the standard particle is 1.6 times, when the standard particle length value is 500μm, the light scattering magnification of the standard particle is 1.5 times, and when the standard particle length value is 1000μm, the magnification of the standard particle is 1.2 times.

[0047] Then, refer to Figure 5a Assuming that the detectable limit pixel size of the image sensor of the optical unit 300 is 1 μm, when the foreign matter magnified length value calculation unit 440 calculates the foreign matter magnified length value l2 of the light scattering foreign matter F detected by the foreign matter detection unit 430 as 1.4 μm, the foreign matter length value judgment unit 450 derives the standard particle length value 0.4 μm corresponding to the standard particle magnified length value 1.4 μm, which is the same as the foreign matter magnified length value 1.4 μm, from the foreign matter length value comparison standard storage unit 420, and judges it as the foreign matter length value l1. In addition, if the foreign matter length value l1 is derived from the foreign matter magnified length value l2 in multiple directions, because they are all the same, it can be judged as a circular foreign matter F, and the foreign matter F smaller than the pixel limit of the sensor 1 μm cannot be detected using a conventional optical detection device, but as described above, in the embodiment of the present invention, the foreign matter F smaller than the pixel limit of the image sensor can be detected.

[0048] In addition, refer to Figure 5b When the foreign matter magnified length calculation unit 440 calculates the long-axis foreign matter magnified length value a2 of the light scattering foreign matter F detected by the foreign matter detection unit 430 as 750μm, and the short-axis foreign matter magnified length value a2 is calculated as 480μm, the foreign matter length value judgment unit 450 judges it as the long-axis foreign matter length value a1 by deriving the standard particle length value 500μm corresponding to the standard particle magnified length value of 750μm from the foreign matter length value comparison standard storage unit 420, and judges it as the short-axis foreign matter length value b1 by deriving the standard particle length value 300μm corresponding to the standard particle magnified length value 480μm from the foreign matter length value comparison standard storage unit 420, and thus it can be analyzed as a foreign matter with a roughly elliptical shape.

[0049] In addition, refer to Figure 5cWhen the foreign matter magnified length calculation unit 440 calculates that the long-axis foreign matter magnified length value a2 of the light scattering foreign matter F detected by the foreign matter detection unit 430 is 750μm, and the short-axis foreign matter magnified length value a2 is calculated to be 200μm, the foreign matter length value judgment unit 450 derives the standard particle length value 500μm corresponding to the standard particle magnified length value 750μm from the foreign matter length value comparison standard storage unit 420, and judges it as the long-axis foreign matter length value a1, and derives the standard particle length value 100μm corresponding to the standard particle magnified length value 200μm from the foreign matter length value comparison standard storage unit 420, and judges it as the short-axis foreign matter length value b1. Since the length of the long axis is much longer than the short axis, it can be analyzed as fibrous.

[0050] In this way, in the above embodiment, the size, shape, etc. of the foreign body are derived based on the foreign body length values ​​of the major axis and the minor axis, but it is also possible to add the foreign body length values ​​calculated in directions other than the major axis and the minor axis for analysis together to derive a more accurate size, shape, etc.

[0051] In addition, the user device 400 also includes a light scattering standard particle RGB value extraction unit 471, a foreign matter color comparison standard storage unit 472, a light scattering foreign matter RGB value extraction unit 473 and a foreign matter color judgment unit 474, and can confirm the actual color of the foreign matter F based on the light scattering foreign matter F.

[0052] The light scattering standard particle RGB value extraction unit 471 pre-irradiates a predetermined amount of light to the standard particles according to color through multiple light sources 210, and extracts the light scattering standard particle RGB value from the image taken by the optical unit 300 according to the light scattering of the standard particles. However, by repeating this operation multiple times for each color of the standard particles, the range of the light scattering standard particle RGB value of each color can be determined. For example, the light scattering standard particle RGB value range of standard particle colors such as black, white, red, green, blue, and yellow can be extracted. The light scattering standard particle RGB value can be expressed as the range of each R, G, and B component. For example, when the color of the standard particle is red, the range of the light scattering standard particle RGB value can be determined to be R ≥ 200, 50 < G < 150, and 50 < B < 150.

[0053] RGB values ​​are a way of expressing images by mixing red (R), green (G), and blue (B). Images are created by gathering many small squares called pixels. Each pixel is created by a combination of red, green, and blue. Red, green, and blue can be represented by numbers in 256 levels of color from 0 to 255. For example, RGB (255, 0, 0) can be represented as red, and RGB (255, 100, 0) can be represented as red mixed with green. But even if it is not the actual color of the standard particle, the light scattering color of the standard particle has a unique RGB value, and these light scattering standard particle RGB values ​​have different representations according to the actual color of the standard particle.

[0054] The foreign matter color comparison standard storage unit 472 matches the standard particle color with the range of the light scattering standard particle RGB value and stores it as a comparison standard for the foreign matter color.

[0055] The light scattering foreign matter RGB value extraction unit 473 extracts the light scattering foreign matter RGB value from the light scattering image of the foreign matter F detected by the foreign matter detection unit 430. At this time, if the light scattering size of the foreign matter F in the image spans multiple pixels, multiple light scattering foreign matter RGB values ​​can be extracted for each pixel, and since these are all colors scattered by one foreign matter F, such multiple light scattering foreign matter RGB values ​​have similar ranges. For example, when the size of the light scattering of the red foreign matter F spans multiple pixels, such multiple light scattering foreign matter RGB values ​​have no significant difference from each other and have similar ranges.

[0056] The foreign matter color judgment unit 474 searches for the range of the light scattering standard particle RGB value including the light scattering foreign matter RGB value, and at this time searches for the range of the light scattering standard particle RGB value whose R, G, and B components of the light scattering foreign matter RGB value are included in the range of the R, G, and B components of the light scattering standard particle RGB value. Then, the standard particle color matching the searched range of the light scattering standard particle RGB value is derived from the comparison standard of the foreign matter color comparison standard storage unit 472, and is judged as the foreign matter color. In this way, by judging the color of the foreign matter, the source of the foreign matter F can be easily judged, thereby preventing the additional influx of the foreign matter F. For example, if the color of the foreign matter is judged to be red, it can be judged that the foreign matter F is transmitted from the operator's clothes.

[0057] As an example, when the color of the standard particle is red, it is assumed that the range of the standard particle RGB value stored in the foreign matter color comparison standard storage unit 472 is R ≥ 200, 50 < G < 150, 50 < B < 150, see Figure 5dIf the light scattering foreign matter F from the image captured by the optical unit 300 spans four pixels, the light scattering foreign matter RGB value extraction unit 473 of the user device 400 extracts the foreign matter RGB value for each pixel. At this time, if the light scattering foreign matter RGB value of the first pixel P1 is RGB(220,120,120), the light scattering foreign matter RGB value of the second pixel P2 is RGB(210,110,90), the light scattering foreign matter RGB value of the third pixel P3 is RGB(210,90,110), and the light scattering foreign matter RGB value of the fourth pixel P4 is RGB(215,120,110), when the foreign matter color judgment unit 474 compares the light scattering foreign matter RGB values ​​of the four pixels with the range of the light scattering standard particle RGB values, they match red, and therefore the foreign matter color is judged to be red.

[0058] In addition, a foreign matter type analyzer may be connected and installed to the optical unit 300 to analyze the type of foreign matter F contained in the object M. For example, by connecting and installing a Raman spectrophotometer or FT-IR (Fourier transform infrared spectroscopy) on the optical unit 300, the type of foreign matter F can be accurately analyzed. Since foreign matter analysis using this type of foreign matter analyzer is already a known technology, a detailed description will be omitted.

[0059] Industrial Applicability

[0060] The optical foreign matter detection device using light scattering and image analysis of the present invention can detect and analyze foreign matter by combining light scattering and image analysis, thereby determining the actual size, shape, area and color of the foreign matter, and can determine the path through which the foreign matter enters, thereby achieving pollution control in the clean room. Moreover, the processing speed of detecting foreign matter and analyzing images is fast, and foreign matter smaller than the pixel limit of the image sensor can be detected. It has high reliability by preventing errors in detecting foreign matter, can be placed on an object for use without a stage, is portable, and can be easily moved to an object for use, thus having industrial practicality.

Claims

1. An optical foreign matter detection device using light scattering and image analysis, which is used to detect and analyze foreign matter contained in an object, the optical foreign matter detection device comprising: Optical housing; a light irradiation unit connected to the lower part of the optical housing and provided with a plurality of light sources for irradiating light to the object on the lower side, wherein the light sources irradiate light with a predetermined light amount so that light scattering can be generated according to the foreign matter; an optical unit built into the upper part of the optical housing, photographing the object and generating an image so that foreign matter contained in the object can be detected by utilizing light scattering of the foreign matter according to the light irradiated by the light source; and a user device for receiving, storing, reproducing and analyzing the image generated by the optical unit, The user device calculates the magnified length value of the light-scattered standard particles based on light irradiation of the standard particle length values ​​of multiple standard particles having a correlation that the light scattering magnification of the standard particles decreases as the standard particle length value increases, and creates a correlation chart between the standard particle length values ​​and the standard particle magnified length values, and saves it as a comparison standard for the foreign matter length value. The optical unit calculates the light-scattered foreign matter magnified length value for the foreign matter detected in the captured object image, and derives the corresponding standard particle length value based on the standard particle magnified length value that is the same as the foreign matter magnified length value to determine the length value of the foreign matter. The size, shape and area of ​​the foreign matter can be confirmed based on the foreign matter length value, and the color of the foreign matter can be confirmed from the light-scattered foreign matter. The user device includes: a standard particle magnified length value calculation unit, for a plurality of standard particles having a correlation relationship that as the standard particle length value increases, the light scattering magnification of the standard particles decreases, and calculating the standard particle magnified length value of the light scattering according to each standard particle length value from an image captured by an optical unit through a plurality of light sources irradiated with a predetermined amount of light and light scattered according to the standard particles; a foreign matter length value comparison standard storage unit, for creating a correlation relationship chart between the standard particle length value and the standard particle magnified length value, and storing it as a comparison standard for the foreign matter length value; a foreign matter detection unit, for detecting light-scattering foreign matter from the object image captured by the optical unit; a foreign matter magnified length value calculation unit, for calculating the light-scattering foreign matter magnified length value of the foreign matter detected by the foreign matter detection unit; a foreign matter length value judgment unit, for deriving the standard particle length value corresponding to the standard particle magnified length value that is the same as the foreign matter magnified length value from the foreign matter length value comparison standard storage unit, thereby judging the foreign matter length value; a foreign matter analysis unit, for determining the foreign matter length value according to the foreign matter length value comparison standard storage unit; The foreign matter length value judging unit analyzes the size and shape of the foreign matter and calculates the area of ​​the foreign matter; the judging unit judges whether the object is contaminated based on the information analyzed by the foreign matter analyzing unit; the light scattering standard particle RGB value extracting unit extracts the light scattering standard particle RGB value from the image captured by the optical unit according to the light scattering of the standard particles by the standard particles according to the color in advance through multiple light sources with a predetermined amount of light; the foreign matter color comparison standard storage unit matches the range of the light scattering standard particle RGB value with the color of the standard particles and stores it as a comparison standard for the foreign matter color; the light scattering foreign matter RGB value extracting unit extracts the light scattering foreign matter RGB value from the light scattering image of the foreign matter detected by the foreign matter detection unit; and the foreign matter color judging unit searches for the light scattering standard particle RGB value range that includes the light scattering foreign matter RGB value, and determines it as the foreign matter color by deriving the standard particle color that matches the searched light scattering standard particle RGB value range from the foreign matter color comparison standard storage unit. Among them, the foreign matter enlarged length value calculation unit can calculate the foreign matter enlarged length values ​​of the major axis and the minor axis respectively, and the foreign matter length value judgment unit can derive the foreign matter length values ​​of the major axis and the minor axis respectively.

2. The optical foreign matter detection device using light scattering and image analysis according to claim 1, characterized in that: The light source of the light irradiation unit irradiates the object at an angle of 1 to 60 degrees.

3. The optical foreign matter detection device using light scattering and image analysis according to claim 1, characterized in that: The light source of the light irradiation unit includes a plurality of lower light sources arranged symmetrically to each other, and a plurality of upper light sources arranged symmetrically at positions higher than the lower light sources. The lower light source and the upper light source are alternately arranged along the periphery of the light irradiation unit to irradiate light at different angles. The light irradiation angle of the lower light source is 1 to 30 degrees, and the light irradiation angle of the upper light source is 31 to 60 degrees.

4. The optical foreign matter detection device using light scattering and image analysis according to claim 1, characterized in that: The optical housing has a built-in optical unit at the upper part, and a light irradiation unit is connected to the lower part. A light scattering unit is formed between the optical unit and the light irradiation unit, the diameter of which decreases upward and provides a dark room, so that light scattering is generated according to foreign matter due to the light irradiation of the light irradiation unit, and a handle is formed on the outside.

5. The optical foreign matter detection device using light scattering and image analysis according to claim 4, The light irradiation unit comprises: a light irradiation ring connected to the lower portion of the light scattering unit to protrude outward and having a through hole formed inside to form a ring shape; a light source installed in plural along the inside of the light irradiation ring to irradiate light to the object from multiple directions; and a bonding ring formed at a lower portion of the light irradiation ring to ensure close contact with the surface of the object.

6. The optical foreign matter detection device using light scattering and image analysis according to claim 5, The fitting ring includes, by weight, 30% to 50% of polyphenylene sulfide resin, 15% to 25% of styrene-butadiene rubber, 10% to 20% of polyurethane resin, 10% to 20% of polymethyl methacrylate, 5% to 10% of 2-mercaptoadenine and 1% to 5% of a light absorber.

7. The optical foreign matter detection device using light scattering and image analysis according to claim 1, further comprising: A foreign matter type analyzer is connected to the optical unit and is capable of determining the type of foreign matter contained in the object.

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