Foreign matter / defect inspection apparatus, image generation apparatus in foreign matter / defect inspection, and foreign matter / defect inspection method

Abstract

A pixel unit composed of at least one light-receiving element of a light-receiving element array (photodiode array) corresponds one-to-one to a light source, and only when the light source emits light, a light beam is detected by at least one light-receiving element (one pixel unit) corresponding to the light source. Therefore, only one light beam collimated or further substantially condensed into a light spot is shot into a "foreign matter / defect" in an inspection object, and the light-receiving element can only separate and detect scattered light, so even if the inspection object has light scattering properties and has a thickness, "foreign matter / defect" can be detected with good S / N (with little crosstalk).

Description

TECHNICAL FIELD

[0001] The present application relates to a method and apparatus for inspecting a foreign object, a scratch, a bump, a defect, a loss, and a foreign object attached to an inspection object having a thickness in a light scattering transmission medium, and an image generating apparatus for the detected foreign object. BACKGROUND

[0002] Conventionally, a system mainly used in a surface inspection apparatus using a light source for a visual field is a representative inspection system such as a line sensor camera, a contact image sensor (hereinafter referred to as CIS), or a combination of a scanning type optical system based on a laser beam and a photoelectric conversion element (photomultiplier diode, avalanche photodiode, CCD sensor, CMOS sensor, or the like), a light receiving optical system including a light guide, or the like, which mostly receives reflected light or fluorescent light from a scratch, a bump, a defect, a loss, a foreign object attached to an inspection object, or the like.

[0003] On the other hand, in a transmission type in which a light receiving system and an illumination system are arranged to face each other with an inspection object interposed therebetween, the inspection object is mostly transparent, thin, and high in transmittance. Moreover, in an inspection object having a thickness, a system for detecting a foreign object, a scratch, a defect, or the like included in the inspection object is rare.

[0004] As a non-destructive inspection apparatus, a well-known X-ray inspection apparatus excellent in transmission is used as X-rays, and thus a radioactive ray management area needs to be provided, and the radiation amount of the radioactive rays to a person also has to be managed. That is, the threshold in deciding a setting place is high. Moreover, since the X-ray inspection apparatus is large and heavy, additional introduction to an existing production line in a factory is not easy. In addition, since the X-ray inspection apparatus is expensive, a large number of inspection points cannot be provided.

[0005] In addition, in the X-ray inspection apparatus, the good transmittance of the X-rays themselves becomes a disadvantage, and objects such as a foreign object, a defect, and a scratch are transmitted, and cases in which the objects cannot be distinguished are also many.

[0006] In an inspection apparatus using a wavelength other than X-rays, in a case where the transmission medium has light scattering properties, a detection apparatus for a foreign object, a scratch, a defect, a loss, or the like included in the transmission medium cannot be realized.

[0007] In the present application, not only is there a technical problem, but also based on research into introduction to a site, the ease of setting, the danger to a human body, the equipment cost of introduction, and the like are considered, and the use of a light source other than X-rays is assumed.

[0008] In Patent Literature 1, a method of detecting a recess, a bend, or the like of a thin film by scanning a laser beam as an illumination light in a main scanning direction is disclosed.

[0009] In Patent Literature 2, by making the optical axis of the illumination optical system and the optical axis of the light-receiving optical system deviate, the transmitted light of the inspection object is suppressed from being buried by direct light and interference light from the illumination optical system. That is, Patent Literature 2 is a method of utilizing information contained in a shadow of transmitted light by irradiating light to an inspection object in order to detect a foreign matter, a defect, or the like present in the inside of the inspection object, at this time, research is made to make a signal from a foreign matter, a defect, and the like in the vicinity of the surface of the inspection object not mixed with a component such as interference light that becomes noise, thereby more easily detecting the foreign matter and the defect.

[0010] In Patent Literature 3, it is disclosed that a plurality of images of an offset mode in which the polarization axes of the illumination side and the light-receiving side are changed are acquired by using polarized light, and after contrast adjustment is performed, a process such as difference is applied, thereby eliminating noise, and accurate foreign matter and defect detection in the inside of an inspection object can be achieved.

[0011] In Patent Literature 4, it is shown that a transmitted image is obtained by making the optical axis of a laser beam scanning optical system coincide with the optical axis of a light-receiving optical system that receives transmitted light of a sample.

[0012] Prior Art Documents

[0013] Patent Literature

[0014] Patent Literature 1: Japanese Patent Application Laid-Open No. 2010-271133

[0015] Patent Literature 2: Japanese Patent Application Laid-Open No. 2015-219090

[0016] Patent Literature 3: Japanese Patent No. 6451980

[0017] Patent Literature 4: Japanese Patent Application Laid-Open No. Hei 3-134609 SUMMARY

[0018] PROBLEMS TO BE SOLVED BY THE INVENTION

[0019] In Patent Literature 1, mainly a scratch, a concave-convex on the surface of an inspection object is detected. The inspection object is mostly a material such as a thin film that is thin in thickness, and inspection can be performed by CIS that is shallow in depth of field. However, when an object having a thickness and a large concave-convex on the surface or a wiring pattern of a laminated electronic substrate and the like is taken as an inspection object, in a conventional CIS that has a depth of field of only 1 to 2 mm, detection becomes difficult. A new inspection apparatus that has a light-receiving optical system that is deep in depth of field and long in working distance (hereinafter, referred to as W.D.) is required.

[0020] An optical system with a deep depth of field is mainly a telecentric optical system, and a line sensor camera with the optical system is mainstream. However, the telecentric optical system is large in size, and it is difficult to use in a narrow conveyance path of a factory. Further, in a case where a conveyance width of a production line of a factory is wide, the field of view of the telecentric optical system is narrow, and thus a large number of cameras are required. Therefore, there is also a difficulty in that the introduction cost becomes high.

[0021] In the case of the optical system of Patent Literature 2, in a case where a foreign matter, a defect, a scratch, or the like in a transmission medium having a large light scattering property is detected, since light near the optical axis of the illumination optical system is not used, the light receiving amount of the light receiving optical system decreases, and further, the transmission light that can be detected is centered on the received scattered light in the inspection object, and thus the interference light scattered by the inspection object itself becomes a dominant component of the signal component, and it is difficult to distinguish and detect the net scattered light of the foreign matter located in a deep portion in the inspection object.

[0022] In the case of Patent Literature 3, there is no problem in a case where the light scattering property of a sample is small, but in a case where the light scattering ability of an inspection object is large, the polarization information is lost due to polarization elimination caused by scattering, and thus it is difficult to appear a difference caused by a shift mode of a polarization axis, and it is difficult to detect a foreign matter, a defect in the inspection object that is a light scattering medium having a transmission property.

[0023] In the case of Patent Literature 4, in the case of an inspection object having a thickness, even in a medium having a high total light transmittance, due to a main cause of a slight refractive index unevenness in the medium, sometimes the optical axis of the laser beam scanning optical system and the light receiving optical system do not coincide, and the signal itself cannot be obtained, that is, a case where a foreign matter, a scratch, a defect, a missing, or the like is overlooked occurs.

[0024] According to the above, in the related art, the depth of field is generally shallow, and thus in a case where the inspection object is a food inspection object, a circuit substrate, or the like having a thickness of 10 mm or more, for example, the information in the depth direction cannot be obtained, and as a result, sometimes the detection of a foreign matter, a defect, a scratch, a missing, or the like cannot be performed. Or, the telecentric optical system having a deep depth of field is large, and thus it is difficult to be disposed in a narrow place. Further, in a case where the total number of foreign matters is inspected in a production line of a factory, in the above-described detection method, a scratch, a defective portion of an electronic substrate cannot be detected, and particularly in a food or the like, there is a risk that a product with a foreign matter mixed therein is shipped.

[0025] According to the above, the depth of field of the existing CIS is shallow, and thus the information in the depth direction of the inspection object having a thickness cannot be grasped, and thus the reliability of the inspection cannot be ensured. Further, the existing method other than the CIS uses a camera lens, a telecentric optical system, and thus it is difficult to avoid the large size, and it is difficult to additionally introduce to an existing production line of a factory, and particularly it is difficult to additionally introduce to a narrow place.

[0026] In Figure 1 a typical CIS is shown. Also in Figure 2 a CIS is shown with a linear illumination optical system. In Figure 1 is a cross-sectional view of the vicinity of the central portion in the long direction of the CIS. Figure 2 is an isometric view. The Z direction is the main scanning direction, and the X direction is the sub-scanning direction. The linear illumination light source 10 is an illumination optical system having an elongated light amount distribution in the main scanning direction.

[0027] In the CIS shown in Figure 1 , two housings 16 are arranged in opposition with the focal plane 20 interposed therebetween. Within each housing 16 is provided a linear illumination light source 10 for illuminating an inspection object located on the focal plane 20. Within one of the housings 16 is provided a lens array 11 and a light receiving portion 12, and light from the illuminated inspection object is guided by the lens array 11 to the light receiving portion 12. The lens array 11 is an optical element that images light from the inspection object on the light receiving portion 12. In Figure 1 the CIS shown in , one of the two linear illumination light sources 10 is arranged on the side of the light receiving portion 12, and the other is arranged on the side opposite the light receiving portion 12, with the focal plane 20 interposed therebetween.

[0028] The light receiving portion 12 is mounted on a substrate 13 fixed to one of the housings 16. Light that has passed through the lens array 11 is received by a light receiving surface 12A of the light receiving portion 12, and a signal corresponding to the amount of light received is output from the light receiving portion 12. By conveying the inspection object in one direction X along the focal plane 20, light from the inspection object is continuously received by the light receiving portion 12, and an image (color image, fluorescent image, etc.) of the inspection object is obtained based on the output signal from the light receiving portion 12.

[0029] Light B3 emitted from one of the linear illumination light sources 10 is transmitted through a protective glass 14 fixed to the housing 16, is reflected by a reflection member 17A provided on the inner surface of a protective glass 14A fixed to the other housing 16, and is guided to the focal plane 20. An ultraviolet light cutoff filter (UV cutoff filter) 15 is provided at an arbitrary position from the focal plane 20 to the light receiving portion 12, for preventing ultraviolet light from entering the light receiving portion 12. In addition, a color filter 18 that passes visible light in a specific wavelength range is provided between the light receiving portion 12 and the UV cutoff filter 15. A substrate 5 for fixing a light source portion 103 (ultraviolet light source, visible light source, etc.) provided in the linear illumination light source 10 is provided in the one housing 16 at a position opposite the bottom surface of the linear illumination light source 10.

[0030] The linear illumination light source 10 has a transparent light guide 101 extending in the length direction L, a light source portion 103 provided near an end surface on one side in the length direction L, and a cover member 102 for holding each side surface of the light guide 101. Light emitted from the light source portion 103 enters the light guide 101, is reflected by a light diffusion pattern P while propagating in the light guide 101, and is emitted from a light emission surface in the arrow direction to become linear illumination light to illuminate the inspection object. However, the illumination optical system diffuses the illumination light due to the light guide 101, and in the case of an inspection object having a thickness and having light scattering transmittance, attenuation of the light-receiving light amount in the optical axis direction becomes a problem. Further, the depth of field of the existing CIS is shallow, and in the case of an inspection object having a thickness, it is difficult to perform inspection of the entire thickness direction, and since the W.D. is narrow, there are many cases in which the inspection itself does not hold true in contact with the inspection object. That is, in the existing CIS optical system, it is very difficult to inspect a foreign matter, a defect, and the like of a transmissive medium having a thickness, and it is even more difficult in the case of having light scattering properties.

[0031] Means for solving the problem

[0032] The present inventors have conducted intensive research on the above-described problem, and as a result, have found that even an inspection object of a light scattering medium having a thickness of 10 mm or more can be inspected for a foreign matter, a defect, a scratch, a missing portion, and the like, and a means for thinness and miniaturization like the existing CIS is achieved. In addition, it has also been found that even a transmissive medium having a greater light scattering ability and a thickness is an inspection object, a foreign matter, a defect, and the like in the inspection object can be detected. Specifically, a manner is provided in which the light beam and scattered light from a foreign matter / defect irradiated by the light beam do not enter a pixel that is not irradiated by the light beam, and an output signal is taken out from only one pixel unit of at least one light-receiving element corresponding one-to-one to the light source, whereby a crosstalk component between pixels can be greatly reduced, and detection of a foreign matter, a defect, and the like in the inspection object is accurate. In the case where at least one light-receiving element of the light-receiving optical system is set as a unit pixel, switching is performed so that the unit pixel outputs only in a residence time of one pixel amount in light scanning illumination light, that is, light beam scanning, and if the light beam and scattered light from a foreign matter / defect irradiated by the light beam do not enter a pixel that is not irradiated by the light beam, a crosstalk component between pixels can be greatly reduced, and detection of a foreign matter, a defect, and the like in the inspection object is accurate. Here, the residence time refers to a period in which a substantially central portion of the light beam traverses one end portion to the other end portion of the one pixel. If the diameter of the irradiation light beam of the illumination optical system is substantially the same in the depth direction of the inspection object and smaller than the pixel resolution of the light-receiving optical system, the inspection object can be substantially uniformly illuminated for a foreign matter, a defect, a scratch, a missing portion, and the like.

[0033] Effects of the invention

[0034] According to the present application, a pixel unit composed of at least one light receiving element of a light receiving element array (photodiode array) corresponds to one light source, and only when the light source emits light, a light beam is detected by at least one light receiving element (one pixel unit) corresponding to the light source. Therefore, only one light beam collimated or further substantially condensed is shot into a "foreign matter / defect" in an inspection object, and the light receiving element can separate only the detected scattered light, so that even if the inspection object has light scattering properties and has a thickness, a "foreign matter / defect" can be detected with good S / N (with little crosstalk). In the present application, in the inspection object having light scattering properties, not only a light scattering transmission medium but also a reflection medium is included. In the present application, since the depth of field on the light source side is deep, even if a reflection medium or the like is an inspection object, "foreign matter / defect" inspection can be performed, and even if a relatively thin inspection object such as a thin film moves along the optical axis direction in a place where the upper and lower of the process transport system move drastically, high-resolution inspection can be performed. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a sectional view of the existing CIS.

[0036] Figure 2 is an exploded perspective view of the linear illumination optical system for the existing CIS.

[0037] Figure 3 is a schematic diagram of the present application.

[0038] Figure 4A is a diagram showing the crosstalk of scattered light to adjacent pixels of the present application.

[0039] Figure 4B is a diagram showing that a parallel light beam is shot into a light receiving lens array, diffuses after being emitted, and becomes background noise on a light receiving element of the present application.

[0040] Figure 5A is a signal in which a crosstalk component and a background noise component are mixed in the existing application.

[0041] Figure 5B is a signal in which there is almost no crosstalk component and background noise component in the present application.

[0042] Figure 6A is a graph showing the forward scattering of 10 μm particle size, and shows the Mie scattering when the transmission medium is polycarbonate and the particle is silica (log scale).

[0043] Figure 6B is a graph showing the forward scattering of 10 μm particle size, and shows the Mie scattering when the transmission medium is polycarbonate and the particle is silica (log scale).

[0044] Figure 6C is a graph showing forward scattering of 17 μm particle diameter, showing Mie scattering when the transmissive medium is polycarbonate and the particle is silica (logarithmic scale).

[0045] Figure 6D is a graph showing forward scattering of 17 μm particle diameter, showing Mie scattering when the transmissive medium is polycarbonate and the particle is silica (logarithmic scale).

[0046] Figure 6E is a graph showing forward scattering of 25 μm particle diameter, showing Mie scattering when the transmissive medium is polycarbonate and the particle is silica (logarithmic scale).

[0047] Figure 6F is a graph showing forward scattering of 25 μm particle diameter, showing Mie scattering when the transmissive medium is polycarbonate and the particle is silica (logarithmic scale).

[0048] Figure 6G is a graph showing forward scattering of 30 μm particle diameter, showing Mie scattering when the transmissive medium is polycarbonate and the particle is silica (logarithmic scale).

[0049] Figure 6H is a graph showing forward scattering of 30 μm particle diameter, showing Mie scattering when the transmissive medium is polycarbonate and the particle is silica (logarithmic scale).

[0050] Figure 7 is a schematic view showing a multi-beam illumination - multi-beam scanning method of the present application.

[0051] Figure 8 shows light scattering caused by a non-transmissive "foreign matter / defect".

[0052] Figure 9A is a schematic view showing a reflective embodiment.

[0053] Figure 9B is a schematic view showing another reflective embodiment of the present application.

[0054] Figure 10 is a schematic view of another way of the present application to further reduce a crosstalk component. is a way of imparting an aperture (array) corresponding to each of the fly's eye lenses of the light receiving system.

[0055] Figure 11 is a schematic view showing the case where adjacent beams overlap after collimation (cross-sectional view from the optical axis direction).

[0056] Figure 12Ais a schematic diagram of an experiment of the edge method of the present application.

[0057] Figure 12B is a schematic diagram of an experiment of the edge method of the prior art.

[0058] Figure 13 is a beam profile of the LD in the embodiment of the present application.

[0059] Figure 14A : In the embodiment of the present application, (1) indicates a graph of the response of the edge signal in the case of two diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0060] Figure 14B : In the embodiment of the present application, (1) indicates a graph of the response of the edge signal in the case of three diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0061] Figure 14C : In the embodiment of the present application, (1) indicates a graph of the response of the edge signal in the case of four diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0062] Figure 14D : In the embodiment of the present application, (1) indicates a graph of the response of the edge signal in the case of five diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0063] Figure 15A : According to the prior art, (1) indicates a graph of the response of the edge signal in the case of two diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0064] Figure 15B : According to the prior art, (1) indicates a graph of the response of the edge signal in the case of three diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0065] Figure 15C : According to the prior art, (1) indicates a graph of the response of the edge signal in the case of four diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0066] Figure 15D : According to the prior art, (1) indicates a graph of the response of the edge signal in the case of five diffusion plates (standard value), and (2) indicates a difference between adjacent pixels of the edge response signal (standard value).

[0067] Figure 16 is a schematic diagram representing a simulation model of the present application.

[0068] Figure 17A is a graph representing the result of simulation, indicating a case where a foreign particle is located at the center of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.00 wt%.

[0069] Figure 17B is a graph representing the result of simulation, indicating a case where a foreign particle is located at the center of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.04 wt%.

[0070] Figure 17C is a graph representing the result of simulation, indicating a case where a foreign particle is located at the center of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.08 wt%.

[0071] Figure 17D is a graph representing the result of simulation, indicating a case where a foreign particle is located at the center of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.12 wt%.

[0072] Figure 17E is a graph representing the result of simulation, indicating a case where a foreign particle is located at the center of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.16 wt%.

[0073] Figure 17F is a graph representing the result of simulation in a case where a foreign particle is located at the center of a light-scattering transmissive medium, indicating a comparison of outputs at each concentration of the light-scattering transmissive medium.

[0074] Figure 18A is a graph representing the result of simulation, indicating a case where a foreign particle is located at the light source side end of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.00 wt%.

[0075] Figure 18B is a graph representing the result of simulation, indicating a case where a foreign particle is located at the light source side end of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.04 wt%.

[0076] Figure 18C is a graph representing the result of simulation, indicating a case where a foreign particle is located at the light source side end of a light-scattering transmissive medium, and the concentration of scattering particles of the light-scattering transmissive medium is 0.08 wt%.

[0077] Figure 18Dis a graph showing the result of simulation, showing a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, and the scattering particle concentration of the light scattering transmissive medium is 0.00 wt%.

[0078] Figure 18E is a graph showing the result of simulation, showing a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, and the scattering particle concentration of the light scattering transmissive medium is 0.16 wt%.

[0079] Figure 18F is a graph showing the result of simulation in a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, showing a comparison of the output at each concentration.

[0080] Figure 19A is a graph showing the result of simulation, showing a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, and the scattering particle concentration of the light scattering transmissive medium is 0.00 wt%.

[0081] Figure 19B is a graph showing the result of simulation, showing a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, and the scattering particle concentration of the light scattering transmissive medium is 0.04 wt%.

[0082] Figure 19C is a graph showing the result of simulation, showing a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, and the scattering particle concentration of the light scattering transmissive medium is 0.08 wt%.

[0083] Figure 19D is a graph showing the result of simulation, showing a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, and the scattering particle concentration of the light scattering transmissive medium is 0.12 wt%.

[0084] Figure 19E is a graph showing the result of simulation, showing a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, and the scattering particle concentration of the light scattering transmissive medium is 0.16 wt%.

[0085] Figure 19F is a graph showing the result of simulation in a case where a foreign particle is located at the light source side end portion of the light scattering transmissive medium, showing a comparison of the output at each concentration.

[0086] Figure 20 is a schematic diagram showing that a plurality of pixels constituted by a plurality of light sources arranged in a main scanning direction and at least one light receiving element correspond one-to-one.

[0087] Figure 21It is a diagram that shows a one-to-one correspondence between multiple pixels, consisting of at least one light-receiving element, and a light source, by scanning a light source through a mechanical deflection unit.

[0088] Figure 22 This is a schematic diagram illustrating the selective passing of multiple light beams through a DMD as a light source, with multiple pixels consisting of at least one light-receiving element corresponding one-to-one.

[0089] Figure 23 This is a schematic diagram showing the scanning of a light source, where multiple pixels, consisting of at least one light-receiving element, are mapped one-to-one.

[0090] Figure 24 This is a conceptual diagram of existing inspection methods.

[0091] Figure 25 Viewed from the side Figure 3 The figure shows the following method: when the object being inspected is thick, and when the depth of field of the light-receiving lens array is narrower than the thickness of the object being inspected, the depth of field position is shifted in the direction of the optical axis, and the scattered light is branched by the beam splitter, so that detection can be performed in the entire thickness direction of the object being inspected. Detailed Implementation

[0092] In the present invention, scratches, dents, defects, missing parts, and attached foreign objects in the above-mentioned inspection object having foreign matter and thickness are simply referred to as "foreign matter / defect". As an illustration, in Figure 3 An example of a foreign object / defect inspection apparatus according to the present invention is shown. However, it is also possible to provide an image generation apparatus that processes signals acquired in the foreign object / defect inspection apparatus into image information and outputs it.

[0093] Figure 3The light source 31a is a light source. The light source 31a is a linear arrangement of a plurality of LDs (Laser Diode: hereinafter referred to as LD) or a plurality of LEDs (Light Emitting Diode: hereinafter referred to as LED). 31b is a side view of 31a. The LD is preferably a low coherence LD that does not generate an interference pattern such as a speckle pattern. The light emitted from the light source 31a is collimated by a collimator lens 32a to become a plurality of substantially parallel light beams 33 equal in number to the number of light sources. 32b is a side view of 32a. Note that the light source 31b and the collimator lens 32b shown by the side view (solid line) are actual positions, and 31a and 32a are shown by a broken line. The plurality of substantially parallel light beams 33 are incident on an inspection object 34, and the scattered light 36 after scattering by "foreign matter / defects" 35 in the inspection object 34 is captured within the depth of field of a light receiving lens array 37, condensed to a focal position 39 of the light receiving lens array 37, and incident on a light receiving element array 38. The light receiving element array 38 generally has one line of linear sensors in the sub-scanning direction, but can also have a plurality of lines of linear sensors or area sensors in the sub-scanning direction. The light receiving lens array 37 is preferably a refractive index distribution lens array typified by a SELFOC lens, but can also be a lens array in which a plurality of other spherical lenses or the like are arranged linearly. Alternatively, it can be a structure in which the light collimated by the collimator lens 32a is further substantially condensed. Here, "substantially condensed" is not limited to a structure in which the light emitted by the LED is condensed, but also includes cases in which a beam waist of a laser beam is formed using a condenser lens or the like. The size (beam diameter) of the light beam collimated by the collimator lens 32a or the light beam after the collimated light beam is further substantially condensed is preferably 10 μm, which corresponds to particles in the Mie scattering region, to about 1000 μm, which corresponds to particles in the geometric optics approximation region. However, it can be adjusted so as to reduce the light collimated by the collimator lens 32a, or so as to expand, depending on the depth or thickness of the light scattering transmission medium.

[0094] In the case where the inspection object does not have "foreign matter / defects", since the light is incident on the light receiving lens array 37 in a substantially parallel light beam state, it is not focused, diverges at the focal position 39 of the light receiving lens array 37, and in the light receiving element array (photodiode array) 38, the direct light is attenuated to become a bias component. Therefore, in the light receiving element array (photodiode array) 38, only the signal component (fluctuation component) of the scattered light 36 caused by the "foreign matter / defects" to which the bias component of the direct light is added or subtracted is detected.

[0095] Here, a method of suppressing a crosstalk component in the light-receiving element array (photodiode array) 38 will be described. In the case where the light sources are lit simultaneously, the light is illuminated in a line shape in the arrangement direction of the light-receiving element array (photodiode array) 38. Therefore, in the case where the "foreign matter / defect" is arranged in the arrangement direction, the same light-receiving element (photodiode) receives the scattered light of the "foreign matter / defect" located at different positions simultaneously, and the determination of the position becomes difficult. That is, the position detection resolution is reduced. The crosstalk avoidance method is to make one light source correspond to one photodiode. That is, making the light source and the light-receiving element (photodiode) correspond one-to-one in a pixel unit is one of the means to avoid crosstalk. One pixel is constituted by at least one light-receiving element, but is not limited to the structure in which one pixel is constituted by one light-receiving element, and one pixel can also be constituted by a structure in which a plurality of light-receiving elements are constituted.

[0096] Again, the Figure 3 will be described. In Figure 3 , the combination of the plurality of light sources and the light-receiving elements is provided on one inspection surface of the inspection object. In this case, it is preferable to scan the light beam in the main scanning direction (the arrangement direction of the plurality of light sources) by sequentially lighting the plurality of light sources so that adjacent light sources are not lit simultaneously. At this time, the control section (not shown) that can individually control the operation of each light source functions as a light scanning unit for scanning the light beam. This light scanning unit, the light source 31a, and the collimator lens 32a and the like constitute an illumination optical system. On the other hand, the light-receiving element array (photodiode array) 38 constitutes a light-receiving optical system. In addition, the light-receiving lens array 37 constitutes a lens system that images the light transmitted through the inspection surface of the inspection object on the light-receiving element of the light-receiving element array (photodiode array) 38, and this lens system is included in the light-receiving optical system. However, the light scanning unit can also be a structure in which the light source itself moves in the arrangement direction of the light-receiving element. Alternatively, the light scanning unit can include a mechanical deflection unit for the light from the light source. The mechanical deflection unit is, for example, a polygon mirror, a galvanometer mirror, a resonant mirror, or a digital mirror device, or the like. In addition, the combination of the illumination optical system and the light-receiving optical system can be able to move in the optical axis direction, or can be a plurality of the illumination optical systems and the light-receiving optical systems whose depth of field does not overlap in the optical axis direction corresponding to the plurality of inspection surfaces. In the case where the illumination optical system is a plurality of systems, for example, it can also be a structure in which the plurality of light sources 31a arranged in a line shape in a line direction have a plurality of lines. In this case, it can be a plurality of line-shaped light sources 31a of the same wavelength, or it can be a plurality of line-shaped light sources 31a of different wavelengths. In the case where only the light-receiving optical system does not overlap in the optical axis direction, various units that branch the light are used in the light-receiving optical system. For example, there is a method of using one or a plurality of beam splitters and the like optical elements. Alternatively, there is also a method of separating each wavelength with a dichroic mirror and discriminating the kind of the foreign matter.

[0097] Figure 25 This illustrates a method for branching using a beam splitter. Figure 25 Viewed from the side Figure 3 The diagram illustrates the following method: when the object 34 being inspected is relatively thick, and the depth of field of the light-receiving lens array 37 is narrower than the thickness of the object 34, the depth of field position is shifted in the optical axis direction, and the scattered light is branched using beam splitters 40a and 40b, enabling detection along the entire thickness direction of the object 34. Figure 25 The structure includes three light-receiving lens arrays 37a, 37b, and 37c, light-receiving element arrays 38a, 38b, and 38c, and two beam splitters 40a and 40b. The object under inspection 34 has multiple depth-of-field regions A1 to A3 along the optical axis. The light-receiving lens array 37a and the light-receiving element array 38a correspond to depth-of-field region A1, the light-receiving lens array 37b and the light-receiving element array 38b correspond to depth-of-field region A2, and the light-receiving lens array 37c and the light-receiving element array 38c correspond to depth-of-field region A3. A portion of the light transmitted through the object under inspection 34 is reflected by the beam splitter 40a, focused by the light-receiving lens array 37a, and directed into the light-receiving element array 38a. Conversely, a portion of the light passing through the beam splitter 40a is reflected by the beam splitter 40b, focused by the light-receiving lens array 37b, and directed into the light-receiving element array 38b. Light passing through beam splitter 40b is focused by light-receiving lens array 37c and directed into light-receiving element array 38c. This ensures that the transmittance and reflectance of each beam splitter 40a and 40b are equal relative to those of each light-receiving element array 38a, 38b, and 38c. For example, as... Figure 25 As shown, in the case of a three-branch beam splitter, by setting the reflectivity of the initially incident beam splitter 40a to approximately 33% and the reflectivity of the subsequently incident beam splitter 40b to 50%, the amount of light incident on each of the light-receiving element arrays 38a, 38b, and 38c can be approximately 1:1:1, and the S / N ratio is also approximately equal. As a beam splitter, a beam splitter that is not wavelength-dependent and does not utilize interference effects is preferred.

[0098] Here, the method of the present invention will now be summarized. Figure 20 This is a schematic diagram illustrating a one-to-one correspondence between multiple light sources and multiple pixels, each containing at least one light-receiving element, according to the present invention. Figure 21 This is a schematic diagram showing that a light source is scanned by a mechanical deflection unit (such as a galvanometer mirror, a multifaceted mirror, a resonant mirror, etc.), and a beam of light is corresponding one-to-one with multiple pixels containing at least one light-receiving element. Figure 22 This is a schematic diagram illustrating how multiple light sources are selectively used as a single light source via a DMD (Digital Micromirror Device, hereinafter referred to as DMD), and how this light source corresponds one-to-one with multiple pixels containing at least one light-receiving element. Figure 23is a schematic view showing that one light source is scanned in the main scanning direction, and the light source corresponds one-to-one to a plurality of pixels constituted by at least one light receiving element. That is, it can be roughly classified into: first, a case where a plurality of light sources arranged apart in the main scanning direction correspond one-to-one to a plurality of light sources constituted by at least one light receiving element (refer to Figure 20 ); second, a case where one light source is scanned in the main scanning direction by a beam scanning unit, or a plurality of light sources selectively become one light source, which corresponds one-to-one to a plurality of pixels constituted by at least one light receiving element (refer to Figure 21 and Figure 22 ); and third, a case where one light source, which corresponds one-to-one to a plurality of pixels constituted by at least one light receiving element arranged in the main scanning direction, is made by a unit that converts one beam into a light beam having a smaller diameter than the light beam (refer to Figure 23 ).

[0099] Next, Figure 24 is a conceptual view showing a prior art inspection method. However, for the sake of simplicity, a light receiving lens system is not illustrated. Figure 24 The prior art light source illuminates the entire inspection object. In addition, it is known that the light receiving element is divided into scattered light and non-scattered light that directly heads toward the light receiving element, the non-scattered light contributes to foreign matter detection, but does not enter the foreign matter, but is mixed into the non-scattered light that directly heads toward the light receiving element from other paths of the inspection object other than the foreign matter, and crosstalk occurs.

[0100] On the other hand, in the case of Figure 23 in the present application, as described above, the light source and the light receiving element in the drawing correspond one-to-one, and therefore the scattered light does not enter the light receiving element that corresponds one-to-one, and it is known that crosstalk is difficult to occur. Figure 23 The conceptual view shown is a method in which the light source (light beam) is moved (scanned), but in the case of Figure 20 , a plurality of light sources (light source array) arranged apart in the main scanning direction correspond one-to-one as appropriate. In the conceptual view shown in Figure 20 , it is also known that the light source and the light receiving element correspond one-to-one, and therefore the scattered light is difficult to enter the light receiving element, and crosstalk can be suppressed. In the cases of Figure 21 and Figure 22 , the light source and the light receiving element also correspond one-to-one, and therefore it is also known that the scattered light is difficult to enter the light receiving element, and crosstalk can be suppressed.

[0101] The actual "foreign matter / defect" is not a perfect sphere, but for simplicity, it is assumed to be a spherical particle. When the foreign matter is a particle having a size of about the wavelength of 10 μm or less, Mie scattering occurs. When the foreign matter is a raindrop having a size of about 100 μm or more, geometric optics can be applied. For example, consider a spherical particle having a diameter of 10 μm, a light scattering transmission medium of resin, and a foreign matter of silicon dioxide. The wavelength of the light from the light source is not limited to one wavelength, and a light source having multiple wavelengths can be used. Here, the wavelength of the light from the light source is assumed to be λ = 830 nm in the near infrared region, the resin is assumed to be polycarbonate, the relative refractive index is assumed to be Nm= 1.57, the foreign matter particle is assumed to be silicon dioxide, and the relative refractive index is assumed to be Np= 1.45. In this case, forward scattering occurs. For a particle having a size of about 100 μm or more, if the particle is transmissive with respect to the wavelength of the light source, the light is focused and diffused by the lens effect, and if the particle is not transmissive at all, the scattering cross section, i.e., the shadow of a circle, is projected by geometric optics. The shadow is represented by the intensity of the light after absorption / diffusion reflection and transmission diffusion. The effect of diffraction caused by the edge of the foreign matter particle can also be considered, but regardless of whether the scattering light including diffraction or the shadow is projected onto the pixel, the sensitivity to the contrast ratio is sufficient. As one example, the intensity of the scattering light from the scattering of the above-described spherical particle is shown in FIG. 10, Figures 6A-6D . Figure 6A and Figure 6B is a graph showing forward scattering of a particle having a size of 10 μm, and Figure 6C and Figure 6D is a graph showing forward scattering of a particle having a size of 17 μm, and shows Mie scattering when the transmissive medium is polycarbonate and the particle is silicon dioxide (logarithmic scale). It is seen that the intensity of the forward scattering light is very strong. The 0-degree direction (the direction of the arrow) is the direction of travel of the light. It is also seen that the forward scattering ability of the particle having a size of 17 μm is about several times larger than that of the particle having a size of 10 μm. Further, a graph showing forward scattering of a foreign matter particle having a size of 25 μm is shown in Figure 6E , Figure 6F . Here, the wavelength of the incident light is λ = 1.55 μm. The intensity of the forward scattering in this case is between that of the particle having a size of 10 μm and that of the particle having a size of 17 μm. Incidentally, the size of 25 μm is close to the resolution of 1200 dpi (pixel resolution: about 21 μm), and the size of 10 μm is close to the resolution of 2400 dpi (pixel resolution: 10 μm or more). Further, a graph showing Mie scattering of a foreign matter particle having a size of 30 μm when the wavelength of the incident light is 1.55 μm is shown in Figure 6G , Figure 6H . It is seen that the intensity of the forward scattering of the particle having a size of 30 μm is about twice that of the particle having a size of 25 μm.

[0102] The following is a description of the method for suppressing the crosstalk component, which is a simplification of the scattered light in the Mie forward scattering region. First, the use of Figure 4A is explained. Figure 4A is a schematic diagram of the scattered light received from the "foreign matter / defect", indicating the crosstalk of the scattered light to the adjacent pixel. The star-shaped mark 41 indicates the foreign matter (defect). The scattered light from the foreign matter (defect) 41 is condensed by the light-receiving lens array 42 and imaged on the light-receiving element array (photodiode array) 43. In Figure 4A , the case where a plurality of light beams are simultaneously incident on the foreign matter is shown.

[0103] Figure 4A The bell-shaped light intensity distribution waveform If on the left side indicates the intensity distribution of the scattered light incident on the light-receiving element array (photodiode array) 43. The scattered light incident on the light-receiving element array (photodiode array) 43 is imaged in a so-called blurred state due to the effects of the aberration and diffraction of the light-receiving lens, and is larger than the actual size of the "foreign matter / defect". That is, even if the size of one pixel of the light-receiving element (photodiode) is the same size as the size of the "foreign matter / defect" in the arrangement direction of the light-receiving element array (photodiode array) 43, the imaged size of the "foreign matter / defect" on the light-receiving element (photodiode) 43 is larger than the size of the "foreign matter / defect" due to the effects of the aberration and diffraction of the light-receiving lens. It is preferable that the aperture angle of the light-receiving lens be sufficiently small with respect to the incident angle of the scattered light, diffused light, or light having a strength that is generated by light scattering in the light transmitted through the inspection surface of the inspection object, or light that is absorbed / diffusely reflected or transmitted and diffused. For example, the aperture angle is preferably about 5 mrad to 15 mrad, and can be 1 mrad to 20 mrad depending on the desired W.D. If the aperture angle is made smaller, the amount of light received becomes smaller, so it is necessary to compensate for this by relatively increasing the power on the light source side. Further, since the transmittance depending on the thickness of the light-scattering transmission medium is directly related to the gain of the light-receiving sensor, by providing a circuit structure having an automatic gain control (AGC) in the light-receiving sensor, it is possible to construct a light-receiving system that has a good S / N regardless of the various transmittances and a wide dynamic range. In addition, at this time, a feedback system (signal processing circuit system) using the average of the outputs up to immediately before the output with respect to the output of any pixel can also be used for any pixel. In addition, if the analysis in the depth direction of the inspection object is performed simultaneously with the analysis in two dimensions of the comprehensive information (output data) of the position-output information of the signal taken in each row, real-time inspection can also be performed. In any case, in order to make the S / N quality of the signal good, research is performed to match the maximum sensitivity range of the light-receiving sensor, and the S / N of the signal is further improved, which results in an expansion of the range of application in the "defect / foreign matter" inspection. Figure 4AThe bell-shaped light intensity distribution waveform Ir on the right side is the intensity distribution of one light beam for illuminating a foreign object according to the present application. If the width in the arrangement direction of the light receiving element array (photodiode array) 43 side of the above-described left and right light intensity distribution waveforms is compared, it is understood that the light intensity distribution waveform If of the light receiving element array (photodiode array) 43 side is spread more than the light intensity distribution waveform Ir of the incident side.

[0104] Next, the two light intensity distribution waveforms If of the light receiving element array (photodiode array) 43 will be described. In the light scattering medium Ms, two "foreign objects / defects" Mfl, Mf2 are arranged in the light receiving element array (photodiode array) 43 so as to be parallel to the light receiving element array (photodiode array) 43 opposite to the light receiving element array (photodiode array) 43, and the interval thereof is the same as the element interval of the light receiving element array (photodiode array) 43. In addition, the light receiving lens array 42 is an equal magnification system, and the W.D. is elongated in advance.

[0105] In this case, it is understood that the light intensity distribution waveform Ifl formed by imaging of one of the "foreign objects / defects" Mfl, Mf2 is also spread on the light receiving element (photodiode) PD2 adjacent to the light receiving element (photodiode) PDl opposite to itself, and crosstalk is generated. The portion where crosstalk is generated is the hatched portion Crl, Cr2 of each light intensity distribution waveform.

[0106] In other words, the light intensity components Crl, Cr2 observed from the pixels adjacent to each other are added to the own net signal component. This is because the crosstalk component mixed into the net signal component of the light receiving elements (photodiodes) of each other becomes noise, and thus the dynamic range is narrowed, and becomes one of the main causes of degradation of the SNR (Signal to Noise Ratio: synonymous with S / N) of the signal.

[0107] Next, the two light intensity distribution waveforms If of the light receiving element array (photodiode array) 43 will be described. In the light scattering medium Ms, two "foreign objects / defects" Mfl, Mf2 are arranged in the light receiving element array (photodiode array) 43 so as to be parallel to the light receiving element array (photodiode array) 43 opposite to the light receiving element array (photodiode array) 43, and the interval thereof is the same as the element interval of the light receiving element array (photodiode array) 43. In addition, the light receiving lens array 42 is an equal magnification system, and the W.D. is elongated in advance. Figure 4B will be described. Figure 4B is a schematic diagram showing that the collimated light beam is incident to the light receiving lens array 42, is spread after being emitted, and becomes background noise on the light receiving elements PDl, PD2. The illumination used in the existing CIS and the like has a light intensity distribution that is continuous in the length direction of the light receiving element array (photodiode array) 43. The light scattered by the "foreign objects / defects" in the light scattering medium Ms is Figure 4AThe collimated light flux 45 is incident into the light-receiving lens array 42 on this basis. Since the light-receiving lens array 42 is set as an equal magnification system, light from outside the depth of field thereof is hardly focused. That is, it is spread on the light-receiving element array (photodiode array) 43 due to divergence, and thus does not contribute to imaging. That is, when the collimated light flux is incident into the light-receiving lens array 42, it is greatly spread on the light-receiving element array (photodiode array) 43 to become a background noise component 46, and becomes a main cause of degradation of S / N. The background noise component 46 is indicated by a portion surrounded by a dotted square. If the background noise increases, it causes degradation of contrast. That is, in the "foreign matter / defect" detection, it is buried in the background noise component, and detection becomes difficult.

[0108] The actually detected signal is mixed with the above-described crosstalk component and background noise component, and as a result, becomes Figure 5A the signal shown in FIG. 6. Figure 5B A case in which the crosstalk component and the background noise component are hardly present is shown. In addition, in the case of geometric optical scattering, due to the shielding effect, the intensity distribution of the "foreign matter / defect" becomes a distribution similar to that of Figure 8 described later.

[0109] In addition to the manner in which the light-receiving element (photodiode) and the light source of the present application Figure 3 are one-to-one corresponding in one pixel unit to perform illumination, a method of further reducing the crosstalk component is described. As Figure 3In the method of simultaneously illuminating in a line shape, components from light sources adjacent to the adjacent photodiodes are mixed in. A method of avoiding this is not to turn on simultaneously, but to make only a pair of light sources and a light-receiving element (photodiode) of a pixel unit corresponding one-to-one act, and next move to a combination of a pair of light sources and a light-receiving element (photodiode) of a pixel unit corresponding one-to-one adjacent thereto, repeating this sequentially until the end. That is, only the light-receiving element of a corresponding pixel unit detects the light beam from the light source at an arbitrary position in the main scanning direction. Such control can be performed by a control section (not shown) including a CPU individually switching the on / off of each light source and each light-receiving element, at which time the control section functions as a detection unit. More specifically, in synchronization with the scanning of the light beam in the illumination optical system, only the light-receiving element output signal near the center portion of the light beam at each scanning position in the plurality of light-receiving elements. Thus, assuming that the light beam diameter is large, the light beam emitted from one light source and collimated by the collimator lens is scattered by "foreign matter / defects", and this scattered light enters the light-receiving element (photodiode) corresponding one-to-one in a pixel unit, even if it enters an adjacent pixel or a pixel adjacent thereto, the adjacent or adjacent pixel does not output, and thus only the net signal for the "foreign matter / defects" corresponding to the light source and at least one light-receiving element (photodiode) of a pixel unit corresponding one-to-one is obtained. At this time, since the above-mentioned crosstalk component is not output from other pixels, only the collimated light beam component entering the light-receiving lens array is received, and crosstalk is very small.

[0110] is shown in Figure 7 . Figure 7 is a schematic diagram showing a multi-beam illumination-multi-beam scanning method. 71 is the light intensity distribution of the incident light beam, and 72 is the scattered light. 73 is the light beam when the light passing through the light-receiving lens array 74 is condensed on the light-receiving element array (photodiode array) 75. The projection images of the scattered light of "foreign matter / defects" Mr1 and Mr2 in the inspection object 76 are Imf1 and Imf2. The imaging size at this time is larger than the size of the "foreign matter / defects" in reality as described above, the imaging size in the arrangement direction of the light-receiving element array (photodiode array) 75 is large due to aberration and diffraction, and is blurred. However, since the site of the light beam incidence is limited, the output of the pixels other than the pixels corresponding one-to-one is limited, and thus there is no output from the pixels other than the pixel 77 corresponding to the incident light beam.

[0111] In addition, it is also possible to simultaneously irradiate the incident light beam corresponding one-to-one to other pixels 77 at a position where crosstalk is not a problem. In this case, as Figure 7As shown, multiple illuminations can be performed simultaneously at the same time, thus resulting in a shorter scanning time. This method is called "multi-beam illumination-multi-scan illumination method," which is different from the "single-beam illumination-single-scan illumination method" mentioned above.

[0112] The spatial resolution of a pixel unit composed of at least one light-receiving element is greater than or equal to the spatial resolution of the light beam on the inspection surface of the object being inspected. Here, the spatial resolution of the light beam corresponds to the beam diameter of the light beam on the inspection surface of the object being inspected. That is, a pixel unit composed of at least one light-receiving element has the ability to distinguish two points that are close to each other within a range less than the beam diameter. In other words, the spatial resolution of the light beam is less than or equal to the spatial resolution of a pixel unit composed of at least one light-receiving element arranged along the main scanning direction.

[0113] The scanning interval of the light beam can also be less than the spatial resolution of a pixel unit composed of at least one light-receiving element arranged in the main scanning direction. In other words, the spatial resolution of a pixel unit composed of at least one light-receiving element is greater than or equal to the scanning interval of the light beam. That is, in a pixel unit composed of at least one light-receiving element, there is the ability to distinguish two points that are close to each other at the scanning interval of the light beam (the interval of the light source).

[0114] Next, the cases where the "foreign object / defect" in the inspected object is a geometric optical scattering region or is non-transmissive will be described. The scattering of the aforementioned "foreign object / defect" will be shown in... Figure 8 . Figure 8 The Cr (the shaded area) is the crosstalk component of the element (center) that causes the illumination beam of the adjacent pixel 77 to move. The transmission component is an intensity distribution with a lower peak than the adjacent bell-shaped intensity distribution. Because the output of the center pixel is low and the output of the adjacent pixels is high, the presence of a "foreign object / defect" Mr can be detected.

[0115] As described above, the "foreign object / defect" in the object being inspected is either a Mie scattering region, a geometric optical scattering region, or a transmissive or non-transmissive region. Furthermore, the form of the signal changes according to surface properties, dielectric constant, etc. However, the "foreign object / defect" can be detected based on the strength of the detected signal. Moreover, if the strength and waveform of the signal caused by the foreign object are used as reference data in advance as a lookup table, the type of "foreign object / defect" can be identified by comparing it with the reference data.

[0116] So far, the object of inspection has been limited to light scattering and transmission media, but the present invention can also be applied to reflective media. Figure 9A An example is shown. Figure 9Ais a schematic view showing a reflective type embodiment, showing a cross section with respect to the length direction of the measurement system. 91 is an inspection object such as an electronic substrate, paper, a film, etc. Light emitted from a light source 92 such as an LED, LD, etc. is collimated by a collimating lens 94 such as a refractive index distribution lens, a spherical lens, etc. and is irradiated onto the inspection object 91. The light receiving optical system has lenses typified by a refractive index distribution lens arranged in an array, and is arranged in a manner that the incident light beam and the reflected light become an included angle. An array of light receiving elements (photodiode array) 96 is arranged at the focal position on the light receiving element side of the light receiving lens array 95.

[0117] In the inspection, information of the inspection object 91 serving as a reference is acquired in advance, and then the inspection of the product is carried out. The information of the inspection object 91 serving as a reference is stored in advance in a memory. When the inspection of the product flowing in the process is carried out, the reference information stored in advance is compared (implementation of the verification). In addition, a case where "foreign matter / defects" are attached, mixed, or present on the inspection object 91 is indicated by an asterisk 98. If "foreign matter / defects" are present on the inspection object 91, data different from the reference data is acquired, a difference from the acquired data is found, and it is determined that "foreign matter / defects" are present on the inspection object 91 and are removed from the process. In addition, in the case where the inspection object 91 is a printed matter, a functional film, etc., the inspection is carried out in the same manner as the above. Figure 9A In the 90Mf of the present application, a case where the element 97 is missing is indicated by a broken line. If the element of the broken line is missing, data different from the reference data is acquired in the same manner as the above, and thus, from the difference, it is determined that the element is missing and is removed from the process. Further, even in the case where a fine wiring on or in the electronic substrate is broken, it is detected as "foreign matter / defects" in the same manner.

[0118] Further, even in the case where there is a protrusion on the electronic substrate and "foreign matter / defects" are blocked by the shadow of the protrusion, it is possible to detect by irradiating the incident light beam from both sides at a symmetric angle and symmetrically arranging the light receiving optical system to an included angle. In addition, in the 90Mf of the present application, a case where the incident light beam is obliquely incident to the substrate is shown, but it is also possible to be vertically incident as in the 90Mf of the present application, and to receive light obliquely with respect to the substrate. In the reflective type, the light receiving angle is arranged considering the N.A. to avoid receiving the direct reflection light. In any case, it is possible to change the arrangement of the measurement system according to the inspection object. Figure 9A Figure 9B In the 90Mf of the present application, a case where the incident light beam is obliquely incident to the substrate is shown, but it is also possible to be vertically incident as in the 90Mf of the present application, and to receive light obliquely with respect to the substrate. In the reflective type, the light receiving angle is arranged considering the N.A. to avoid receiving the direct reflection light. In any case, it is possible to change the arrangement of the measurement system according to the inspection object.

[0119] The method of the present application is also effective in the case where the inspection object is a printed matter, a functional film, etc. That is, in a transmissive type film, the inspection of the presence or absence of a scratch, etc., an opaque printed matter such as paper, etc. uses a reflective type, and it is needless to say that the inspection of a printing defect, etc. is effective. Furthermore, in the present application, even in the case where there is a place where the conveying system moves up and down, since the depth of field is deep, it is possible to be used, and the range of application is expanded.

[0120] ​Further, in the light scattering transmission medium, particularly in the medium with low transmittance, it is sometimes preferable to reduce the above light beam. In this case, the aperture angle of the light beam is determined in consideration of the light receiving solid angle of the light receiving element. Further, in the case where the transmittance of the light scattering transmission medium is high, the reflectance of the reflection medium is high, or the light beam is expanded to some extent, there is also an effect of reducing the light received by the light receiving solid angle of the light receiving element to become background noise. Therefore, according to the transmittance and reflectance of the inspection object, by conducting a study of the method of collimating the light beam, reducing the light beam, expanding the light beam, and the like, the S / N of the signal is further improved. Further, the "reducing or expanding the light beam" refers to further reducing or expanding the collimated parallel light beam. Although the above specific explanation is omitted, simply put, in the case of the light scattering transmission medium, if the light receiving solid angle is assumed to be hardly changed in the depth direction, it is possible to suppress the direct entry of the collimated parallel light beam into the light receiving element, and in the case where the reflection medium is the inspection object, in the case where the light beam is expanded on the inspection surface of the inspection object, it is possible to reduce the entry intensity of the direct illumination light beam at the light receiving solid angle and improve the S / N of the signal based on the light received by the light receiving element. Note that the inspection surface of the inspection object refers to the surface of the inspection object into which the light beam enters, and is not limited to one, and can also be a structure in which the light beam enters a plurality of inspection surfaces.

[0121] Currently, the high density of LEDs is continuously developed, represented by LED printers, and 1200 dpi has been achieved. If this LED array is used, high resolution can be achieved. That is, as long as the emitted light emitted from the LED array is collimated and this collimated light beam is used as a light source instead of Figure 3 In the case of the LED printer, the refractive index distribution lens array is an equal magnification system of the refractive index distribution lens, but the refractive index distribution lens used in the present application uses a lens having a focal point at infinity. If in the future, LDs can be arranged at high density, it is more preferable to use a high-output LD array. Alternatively, it can also be a linear light source in which semiconductor lasers represented by VCSEL (Vertical Cavity Surface Emitting Laser) are arranged on a plane, or arranged in a region. The linear light source is arranged in multiple rows, and further, it is also possible to achieve improvement of inspection accuracy by inspection based on multiple wavelengths.

[0122] By using Figure 3The above-described method will be described again. 31a is an LED or LD array as a light source. 31b is a side view of 31a. 32a is a collimator lens array. 32b is a side view of 32a. 34 is an inspection object, 35 is a "foreign matter / defect" in the inspection object. 37 is a light-receiving lens array. 38 is a light-receiving element array (photodiode array). In addition, 30 is a light beam emitted from the light source 31, and 33 is a light beam emitted from the collimator lens 32. The light beam 33 is incident to the inspection object 34, and then to the "foreign matter / defect" 35. The light beam 33 incident to the "foreign matter / defect" 35 is scattered by the "foreign matter / defect" 35 to become scattered light 36, which is incident to the light-receiving lens array 37, and then to the light-receiving element array 38.

[0123] Next, a schematic diagram showing that the collimated light beam is incident to the light-receiving lens array 42, diffused after emission, and becomes background noise on the light-receiving elements PD1, PD2, i.e. Figure 4B A more excellent removal method of the background noise shown in Figure 4B will be described.

[0124] In the light-receiving optical system of Figure 4B , the background noise cannot be completely removed, but can only be suppressed to a certain extent, and in order to further remove it, only the desired net signal component is required, and further effort is needed. The following describes a study thereof. The biggest disadvantage of the compound eye lens is that, since it is a compound eye lens, the crosstalk component from the adjacent compound eye lens is quite large, and the background noise component is spread on the element surface of the light-receiving element array (photodiode array) 43. Since attenuation is performed in order to generate the spread of the light beam, the crosstalk component becomes small. However, there is still room for improvement, and by further reducing the background noise, the S / N can be further improved. Figure 10 A schematic diagram showing the present method. Figure 10 is a method in which an aperture (array) corresponding to the compound eye lens of the light-receiving system one by one is given.

[0125] Figure 10 101 of the above-described method is a view of the aperture corresponding to the compound eye lens of the light-receiving system one by one from the optical axis direction. 102 shows the cross section of the aperture. At the same time, the N.A. of each aperture 101 on the optical axis of each light source, collimator lens (depending on the case, a condenser lens forming a beam waist), light-receiving lens, and light-receiving element is substantially the same as or smaller than that of the light-receiving lens. Alternatively, the aperture can be disposed on the imaging surface of the light-receiving lens at one time, and the spread light can be received one by one in correspondence. In this case, the one-to-one correspondence is corrected in advance, and only the signal from the one-pixel unit performing the one-to-one correspondence needs to be output.

[0126] Figure 11is a schematic view showing the case where the collimated adjacent light beams overlap. As shown in Figure 11 The collimated light beams can also be larger than the effective diameter of the fly-eye lens of the light receiving system. By increasing the size, detection can be performed without missing foreign matter / defects in the inspection object. 103 is a portion where the collimated light beams overlap, and 104 is a portion where they do not overlap. The "foreign matter / defect" 105 is irradiated on the light beam where the collimated adjacent light beams overlap, and the "foreign matter / defect" 106 is irradiated on the light beam where they do not overlap. As a result, the "foreign matter / defect" located at all positions can be detected.

[0127] The above-described Figure 3 One example of an embodiment of the present application will be described in detail. The light source 31a is easily arrayed and matrixed, and a VCSEL (Vertical Cavity Surface Emitting Laser) having a large power is preferable. Alternatively, an LED array used in an LED printer can also be used. The above-described VCSEL is arranged in a linear shape in a fine and dense manner, and the pitch of the light source 31a is determined in accordance with the pitch of the light receiving element array 38. For example, it is consistent with 600 dpi, 1200 dpi. However, it is not limited to this when used outside the case where it is processed as an image. Next, the VCSEL array is arranged in parallel with the refractive index distribution type lens array. The refractive index distribution type lens array is used as a collimator, and thus a pitch in the vicinity of 1 / 4 pitch is used. Alternatively, it can be in the vicinity of 3 / 4 and the pitch. That is, the pitch is determined in such a manner that the collimated light beams can be emitted. In addition, other than the refractive index distribution type lens, a microlens array in which a spherical lens is made small can also be used. In this case, the microlenses are arranged in parallel with the optical axis of the light source 31a. In the case where the light beams are collimated, the beam waist exists on the emission surface of the VCSEL, and the collimation is performed in such a manner that the beam waist coincides with the focal point of the collimating lens 32.

[0128] In the present application, a laser having a wavelength suitable for the light scattering transmission medium is used, and in particular in food-related applications, a wavelength of λ = 800 nm to 900 nm in the vicinity thereof is used in consideration of the absorption of moisture. There are also media (snacks typified by cocoa) in which the transmittance is low in the above-described band, and in this case, a wavelength used in optical communication in the vicinity of λ = 1500 nm is also used at times. There is also a wavelength region in which the transmittance is high for materials containing a large amount of H2O, CO2, O2, and the like, and thus the wavelength can be selected as needed to illuminate the inspection object. In addition, when the wavelength is selected, a light receiving element having a sensitivity domain in the selected wavelength is used. In the case of a roll paper, a roll film, paper, a resin film, a metal film, and the like other than food, a wavelength in the visible region can also be used.

[0129] In the present embodiment, λ = 830 nm in the near infrared region is used. At this wavelength, the thickness of the light-scattering transmissive medium is 10 mm, and if the beam waist is provided in the central portion of the light-scattering transmissive medium, it is preferable to suppress the change in the beam diameter of about 5% within a distance of ±5 mm. For example, when the size of the emission port of the VCSEL is 10 μm in diameter, according to Equation 1, when the focal length of the SELFOC lens array is f, and when f = 2 mm, the beam diameter d after collimation is d = 210 μm.

[0130] W0= {4 • f • λ / (π • d)} / 2... (Equation 1)

[0131] wherein,

[0132] f: focal length of the lens,

[0133] λ: wavelength of the laser beam,

[0134] d: beam diameter.

[0135] In addition, it can also be a method in which the focal point is focused on the central portion of the light-scattering transmissive medium. That is, the beam waist length can be adjusted in such a manner that it becomes a substantially parallel light beam in the light-scattering transmissive medium. In this case, the beam diameter at the beam waist position is found using Equation 2 of Kogelnik. However, in the light-scattering transmissive medium, since the refractive index in air (in vacuum) is different, it is also necessary to consider the movement of the beam waist position to determine the beam waist position, and the details are described later. Equation 2 of Kogelnik, which represents the propagation of the laser beam, is used when determining the range of the permissible radius of the light beam.

[0136] W 2 (z) = W 0 2[1 + {λ • z / (π • W0 2 )} 2 ]... (Equation 2)

[0137] wherein,

[0138] W 2 (z): beam radius at an arbitrary position in the optical axis direction,

[0139] W0: beam waist radius.

[0140] The beam waist radius W0 is found by Equation 1, and thus, for example, the range of the beam diameter of 5% error can be determined by Equation 2. The result of Equation 2 is 217 μm, and it can be set as the permissible range.

[0141] The position of the beam waist in air (in vacuum) is determined by Equation 1, but in a light scattering transmission medium, the refractive index is larger than in air (in vacuum), and thus the actual beam waist position is farther from the light source side. Also, the beam waist diameter changes in correspondence with the convergence angle becoming shallower. The moving distance Δf of the beam waist can be expressed by Equation 3. That is, it can be determined from the focal distance of the condensing lens when the laser beam is incident to the incident end surface and the beam diameter of the collimated light beam. Since it is the distance of the light beam not considering the vicinity of the diffraction limit, θ' is approximately applied to geometric optics, and is solved by Snell's Law.

[0142] Δf = tan θ' / di... (Equation 3)

[0143] wherein,

[0144] θ: maximum value of the incident angle,

[0145] θ': maximum value of the refracted angle,

[0146] di: beam radius incident to the incident end surface of the light scattering transmission medium.

[0147] Kogelnik's equation cannot be applied in a light scattering transmission medium, and thus it is necessary to solve the beam waist diameter again. Since it is not necessary to use the convergence angle in the vicinity of the beam waist, the refracted angle solved by Snell's Law, which is approximate by geometric optics, is used. The divergence angle Φ of the light beam can be expressed by Equation 4, which represents the diffraction limit.

[0148] φ = 2λ / (π · dms)... (Equation 4)

[0149] wherein,

[0150] λ': wavelength in the light scattering transmission medium,

[0151] dms: beam waist diameter in the light scattering transmission medium,

[0152] λ': N · λ (λ: refractive index in air (in vacuum)).

[0153] According to the above, the beam waist diameter dms in the light scattering transmission medium is a long focus point where the focal length is approximately equal to W.D. In the case where a condenser lens of f = 50 mm, which is a small N.A. (Numerical Aperture), is disposed on the rear side of the collimator lens and on the light source side of the light scattering transmission medium, if the diameter of the incident light beam to the condenser lens is set to 210 μm, the beam waist diameter 2W0 in the case where there is no light scattering transmission medium is 252 μm. Further, it is known that the focal point movement distance in the light scattering transmission medium when using the lens of the above-mentioned focal length is 21 mm. Therefore, in the case where the beam waist position is disposed in the central portion, it is sufficient to lower the illumination optical system from the light scattering transmission medium by 16 mm. In addition, at this time, according to Equation 4, the light beam diameter dms is 377 μm. According to the above, the position of the optical system can be determined according to the thickness and the refractive index of the object to be inspected. In addition, it is also possible to make the optical system into a configuration that can be moved in the optical axis direction.

[0154] Figure 12A A schematic view of an experiment of the edge method representing an embodiment of the present application, Figures 14A-14D A measured result is represented. Figure 12B A schematic view of an experiment of the edge method of the related art is represented, Figures 15A-15D A measured result of the related art is represented. In Figure 12A and Figure 12B In the above, 34a is a diffusion plate. Figure 14A A case where two diffusion plates are represented, Figure 14B A case where three diffusion plates are represented, Figure 14C A case where four diffusion plates are represented, Figure 14D A case where five diffusion plates are represented (standard value). Figure 15A A case where two diffusion plates are represented, Figure 15B A case where three diffusion plates are represented, Figure 15C A case where four diffusion plates are represented, Figure 15D A case where five diffusion plates are represented (standard value). The measured result is for verifying the performance of the present application in place of "foreign matter / defects", the edge is used as a measurement object, and the rising characteristics of the edge signal are observed. In addition, the light scattering transmission medium is set to a diffusion plate Kuraray Comoglass 432L (thickness: t = 2 mm, total light transmittance: 61%, haze: 95%), and in order to confirm / verify the thickness unevenness, the number of sheets is set to two, three, four, and five, and the maximum thickness is set to 10 mm. Figure 14A (1), Figure 14B (1), Figure 14C (1), Figure 14D (1) represents the results of the diffusion plates of each number of sheets, and is a comparative example, Figure 15A (1), Figure 15B (1),Figure 15C (1), Figure 15D (1) indicates the rising characteristics of the edge signal of the prior art. The light source uses a collimated light beam of an LD (Panasonic LNCT28PS01WW). Figure 13 indicates the beam profile of the semiconductor laser in the inspection object. In order to be considered as an array, one LD is moved by the pixel pitch, and the signals of the pixels corresponding to 1 by 1 are obtained sequentially.

[0155] Figure 14A (1), Figure 14B (1), Figure 14C (1), Figure 14D (1) is a graph indicating the edge response (relative intensity) described above in one example of the embodiment of the present application. The pixel size is about 62 μm in the main scanning direction. In addition, Figure 14A (2), Figure 14B (2), Figure 14C (2), Figure 14D (2) indicates the difference (relative intensity) of the outputs from the adjacent pixels. From Figure 14A (2), Figure 14B (2), Figure 14C (2), Figure 14D (2), it is clear that the difference between the adjacent pixels exists, and the difference in the relative intensity is 10% of the peak value, and thus it is known that the discrimination of each pixel (corresponding to 400 dpi) is possible. Further, if the size of the element is reduced, the pixel size and the pitch are reduced, the pixel size and the pitch are reduced, 600 dpi, 1200 dpi are achieved, and further, resolutions higher than that are achieved. The size of the light receiving element (pixel size) is preferably set to satisfy 200 dpi or more.

[0156] Figures 15A-15D The edge response (relative intensity) according to the prior art is shown as a comparative example. There is a clear difference between the present application and the prior art, and it is known that in the prior art, there is no pixel resolution in any of the diffusion plates, and the graph indicating the difference is buried in the background noise (random noise), and foreign matter detection is not possible. In contrast, it is known that the present application can perform foreign matter detection regardless of the thickness of the diffusion plate.

[0157] Next, the result of the response of the light receiving sensor when "foreign matter / defect" exists in the light scattering transmission medium in the thickness (t = 30 mm) of the optical axis direction is shown by a simulation model. The schematic diagram of the model is shown in Figure 16The PMMA was selected as the inspection object, and 2-μm-diameter silicone spherical particles were used as the light scattering particles. The concentration was varied between 0.04 wt% and 0.20 wt%. The light source was collimated, and the cross-sectional dimension was set to 150 μm, which is larger than the light receiving element (main scanning direction dimension: 62 μm). Figures 17A-17F is a graph showing the simulation results. The foreign matter was a 100-μm-diameter sphere, and was an absorber having an interface with a transmittance of 0%. In addition, the foreign matter particle was located at the center of the inspection object. Figure 17A represents the case where the scattering particle concentration was 0.00 wt%, Figure 17B represents the case where the scattering particle concentration was 0.04 wt%, Figure 17C represents the case where the scattering particle concentration was 0.08 wt%, Figure 17D represents the case where the scattering particle concentration was 0.12 wt%, Figure 17E represents the case where the scattering particle concentration was 0.16 wt%, Figure 17F represents the output comparison at each concentration.

[0158] In addition, in the case where the foreign matter particle was located at a position deviated by ±14.5 mm from the center of the inspection object, Figures 18A-18F , Figures 19A-19F a graph showing the simulation results of the foreign matter particle located at a position deviated by ±14.5 mm from the center of the inspection object is shown. That is, the foreign matter particle was located at a depth of 0.5 mm from the end of the inspection object. Figures 18A-18F represents the case where the foreign matter particle was located at the light source side end of the inspection object, Figures 19A-19F represents the case where the foreign matter particle was located at the light receiving element side end of the inspection object. According to this simulation result, both are very similar responses to the case where the foreign matter particle is located at the center of the light scattering transmissive medium, and very well represent the effects of the present application, and are very excellent in the suitability for the detection of "foreign matter / defects" in a light scattering transmissive medium having a thickness.

[0159] As described above, the present application is excellent in the detection accuracy of "foreign matter / defects" in a light scattering transmissive medium, compared to the related art. In addition, the mode of the present application can also be applied to the detection of "foreign matter / defects" in a reflective medium. Further, it is also possible to generate an image based on the light receiving signal from the light scattering transmissive medium, and to perform further analysis of the defective product removed according to the level of the detection signal. In this case, it is assumed that the inspection is performed mainly off-line, but by improving the signal processing speed, it is also possible to perform on-line analysis automatically. In this way, it is possible to perform an inspection that cannot be applied in the related art, the quality of the inspection is further improved, and further, the improvement of the quality of the product as the inspection object can be achieved.

[0160] <Effects>

[0161] As described above, by using a collimated parallel light beam having a diameter small enough, or by adjusting the beam waist to be a substantially parallel light beam in a light-scattering transmissive inspection object, further, by adjusting the beam convergence angle, the expansion angle according to the inspection object, it is possible to suppress the overlapping of the expansion of light caused by light scattering (diffusion), in addition to this, by selecting the output signal from the pixel in a manner that only receives the signal in the vicinity of the optical axis of the light beam in the light-receiving element corresponding one-to-one to the light source at each irradiation position, it is possible to suppress the crosstalk between the pixels, and it is possible to separately detect the light that is the cause of the noise of the background caused by scattered light (diffused light), directly incident light, and the change in the amount of light caused by "foreign matter / defects", so it is possible to clarify the "foreign matter / defects" object in the inspection object, and it is possible to perform accurate inspection.

[0162] BRIEF DESCRIPTION OF DRAWINGS

[0163] 10: linear illumination light source;

[0164] 11: lens array;

[0165] 12: light-receiving portion;

[0166] 31a, 31b: light source;

[0167] 32a, 32b: collimator lens;

[0168] 33: light beam;

[0169] 34: inspection object;

[0170] 36: scattered light;

[0171] 37: light-receiving lens array;

[0172] 38: light-receiving element array;

[0173] 39: focal position;

[0174] 42: light-receiving lens array;

[0175] 45: light beam;

[0176] 74: light-receiving lens array;

[0177] 76: inspection object;

[0178] 77: pixel;

[0179] 91: inspection object;

[0180] 92: light source;

[0181] 94: collimator lens;

[0182] 95: light-receiving lens array

Claims

1. A foreign object / defect inspection device, characterized in that, The foreign object / defect inspection device includes: An illumination optical system comprising a light scanning unit that scans a light beam obtained by collimating light emitted from multiple light sources arranged linearly along the main scanning direction relative to at least one inspection surface of an inspection object having light scattering properties, or scans a light beam obtained by further focusing the collimated light beam emitted from multiple light sources arranged linearly along the main scanning direction. A light-receiving optical system is arranged parallel to the main scanning direction of the illumination optical system in a one-to-one correspondence between the light source and a pixel unit consisting of at least one light-receiving element. The light-receiving optical system includes multiple light-receiving elements. The light beam, after passing through the inspection surface of the object under inspection, illuminates a foreign object or defect located on the object under inspection. The multiple light-receiving elements receive scattered light, diffused light, or light of varying intensity that is absorbed / diffused and reflected, or transmitted and diffused from the foreign object or defect. as well as The detection unit detects the light beam from the light source at any position along the main scanning direction of the illumination optical system using only the corresponding light-receiving element. The spatial resolution of a pixel unit composed of the at least one light-receiving element is greater than or equal to the spatial resolution of the light beam formed by the illumination optical system on the inspection surface of the object being inspected.

2. The foreign object / defect inspection device according to claim 1, characterized in that, The size of the collimated beam or the beam obtained by further focusing the collimated beam is greater than 10 μm and less than 1000 μm, and the size of the light-receiving element is greater than 200 dpi.

3. The foreign object / defect inspection device according to claim 1, characterized in that, The light source of the illumination optical system is a light source composed of at least one LD, and is capable of scanning the laser beam emitted from the light source along the arrangement direction of the plurality of light-receiving elements on the inspection surface of the object being inspected to obtain a light beam, or to obtain a light beam by further focusing the aligned light beam.

4. The foreign object / defect inspection device according to claim 1, characterized in that, The light source of the illumination optical system is a light source composed of at least one LED, and is capable of scanning the laser beam emitted from the light source along the arrangement direction of the plurality of light-receiving elements on the inspection surface of the object being inspected to obtain a light beam, or to obtain a light beam by further focusing the aligned light beam.

5. A foreign object / defect inspection device, characterized in that, The foreign object / defect inspection device includes: An illumination optical system comprising a light scanning unit that scans a light beam obtained by converging light emitted from multiple light sources arranged linearly along the main scanning direction relative to at least one inspection surface of an inspection object having light scattering properties, or by scanning a light beam obtained by expanding light emitted from multiple light sources arranged linearly along the main scanning direction. A light-receiving optical system is arranged parallel to the main scanning direction of the illumination optical system in a one-to-one correspondence between the light source and a pixel unit consisting of at least one light-receiving element. The light-receiving optical system includes multiple light-receiving elements. The light beam, after passing through the inspection surface of the object under inspection, illuminates a foreign object or defect located on the object under inspection. The multiple light-receiving elements receive scattered light, diffused light, or light of varying intensity that is absorbed / diffused and reflected, or transmitted and diffused from the foreign object or defect. as well as The detection unit detects the light beam from the light source at any position along the main scanning direction of the illumination optical system using only the corresponding light-receiving element. The spatial resolution of a pixel unit composed of the at least one light-receiving element is greater than or equal to the spatial resolution of the light beam formed by the illumination optical system on the inspection surface of the object being inspected.

6. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The scanning interval of the light beam in the illumination optical system is below the spatial resolution of a pixel unit composed of at least one light-receiving element arranged along the main scanning direction.

7. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The object being inspected is a medium that has the property of transmitting light emitted from the light source.

8. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The object being inspected is a medium that has the property of reflecting light emitted from the light source.

9. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The light-receiving optical system has a lens system that images light transmitted through the inspection surface of the object being inspected onto the light-receiving element.

10. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The detection unit, in sync with the scanning of the light beam in the illumination optical system, outputs signals only to the light-receiving elements near the center of the light beam at each scanning position among the plurality of light-receiving elements.

11. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The foreign object / defect inspection device has a combination of the light source and at least one light-receiving element of one pixel unit on one inspection surface of the object to be inspected.

12. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The optical scanning unit moves the light source itself in the direction in which the light-receiving elements are arranged.

13. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The combination of the illumination optical system and the light-receiving optical system is movable in the direction of the optical axis.

14. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The optical scanning unit includes a mechanical deflection unit for light from the light source.

15. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The light-receiving element is a line sensor.

16. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The light-receiving element is a region sensor.

17. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The light-receiving optical system includes a lens array.

18. The foreign object / defect inspection device according to claim 17, characterized in that, The lens array has compound eye lenses that correspond one-to-one with each pixel. An aperture corresponding to each pixel is provided between the compound eye lens and each pixel, and each aperture is located on the optical axis of each light source.

19. The foreign object / defect inspection device according to claim 9, characterized in that, The aperture angle of the lens system is 1 mrad to 20 mrad, relative to the incident angle of the scattered light, diffused light, or light with varying intensity after absorption / diffusion reflection or transmission diffusion in the light transmitted through the inspection surface.

20. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The foreign object / defect inspection device has a light source with multiple wavelengths.

21. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The multiple light sources arranged in a linearly separated manner have multiple lines, and are either multiple linear light sources of the same wavelength or multiple linear light sources of different wavelengths.

22. The foreign object / defect inspection device according to claim 1 or 5, characterized in that, The foreign object / defect inspection device has multiple inspection surfaces for the object being inspected and multiple depth-of-field regions in the optical axis direction.

23. An image generation apparatus, characterized in that, The image generation device processes the signals acquired in the foreign object / defect inspection device according to claim 1 or 5 into image information and outputs them.

24. A method for inspecting foreign objects / defects, characterized in that, The foreign object / defect inspection method includes: The step of scanning a beam using an illumination optical system includes a light scanning unit that scans a beam obtained by collimating light emitted from multiple light sources arranged linearly along the main scanning direction relative to at least one inspection surface of an inspection object that has light scattering properties, or scans a beam obtained by further focusing the collimated beam of light emitted from multiple light sources arranged linearly along the main scanning direction. The step of receiving a light beam through a light-receiving optical system is that the light-receiving optical system is configured parallel to the main scanning direction of the illumination optical system in a one-to-one correspondence between the light source and a pixel unit consisting of at least one light-receiving element. The light-receiving optical system includes multiple light-receiving elements. The light beam, after passing through the inspection surface of the object being inspected, illuminates a foreign object or defect located on the object being inspected. The multiple light-receiving elements receive scattered light, diffused light, or light of varying intensity that is absorbed / diffused and reflected, or transmitted and diffused from the foreign object or defect. as well as The step of detecting a light beam from the light source at any position along the main scanning direction of the illumination optical system using only the corresponding light-receiving element. The spatial resolution of a pixel unit composed of the at least one light-receiving element is greater than or equal to the spatial resolution of the light beam formed by the illumination optical system on the inspection surface of the object being inspected.

25. A method for inspecting foreign objects / defects, characterized in that, The foreign object / defect inspection method includes: The step of scanning a beam using an illumination optical system includes a light scanning unit that scans a beam obtained by adjusting light emitted from multiple light sources arranged linearly along the main scanning direction in a convergent manner relative to at least one inspection surface of an inspection object having light scattering properties, or by adjusting light emitted from multiple light sources arranged linearly along the main scanning direction in an expanded manner. The step of receiving a light beam through a light-receiving optical system is that the light-receiving optical system is configured parallel to the main scanning direction of the illumination optical system in a one-to-one correspondence between the light source and a pixel unit consisting of at least one light-receiving element. The light-receiving optical system includes multiple light-receiving elements. The light beam, after passing through the inspection surface of the object being inspected, illuminates a foreign object or defect located on the object being inspected. The multiple light-receiving elements receive scattered light, diffused light, or light of varying intensity that is absorbed / diffused and reflected, or transmitted and diffused from the foreign object or defect. as well as The step of detecting a light beam from the light source at any position along the main scanning direction of the illumination optical system using only the corresponding light-receiving element. The spatial resolution of a pixel unit composed of the at least one light-receiving element is greater than or equal to the spatial resolution of the light beam formed by the illumination optical system on the inspection surface of the object being inspected.

26. The foreign matter / defect inspection method according to claim 24 or 25, characterized in that, The scanning interval of the light beam in the illumination optical system is below the spatial resolution of a pixel unit composed of at least one light-receiving element arranged along the main scanning direction.

27. The foreign matter / defect inspection method according to claim 24 or 25, characterized in that, The foreign object / defect inspection method has a light source with multiple wavelengths.

28. The foreign matter / defect inspection method according to claim 24 or 25, characterized in that, The multiple light sources arranged in a linearly separated manner have multiple lines, and are either multiple linear light sources of the same wavelength or multiple linear light sources of different wavelengths.

29. The foreign matter / defect inspection method according to claim 24 or 25, characterized in that, The foreign object / defect inspection method has multiple inspection surfaces of the object to be inspected and multiple depth areas in the optical axis direction.

Images