WO2023182390A1 - Procédé d'inspection d'élément optique, dispositif d'inspection et procédé de fabrication - Google Patents

Procédé d'inspection d'élément optique, dispositif d'inspection et procédé de fabrication Download PDF

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Publication number
WO2023182390A1
WO2023182390A1 PCT/JP2023/011357 JP2023011357W WO2023182390A1 WO 2023182390 A1 WO2023182390 A1 WO 2023182390A1 JP 2023011357 W JP2023011357 W JP 2023011357W WO 2023182390 A1 WO2023182390 A1 WO 2023182390A1
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WIPO (PCT)
Prior art keywords
optical member
inclination angle
captured image
light
recess
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PCT/JP2023/011357
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English (en)
Japanese (ja)
Inventor
俊介 佐々木
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日東電工株式会社
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Publication of WO2023182390A1 publication Critical patent/WO2023182390A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/958—Inspecting transparent materials or objects, e.g. windscreens

Definitions

  • the present invention relates to an inspection method, an inspection device, and a manufacturing method for optical members for lighting devices.
  • the present invention relates to an optical member inspection method, inspection apparatus, and manufacturing method that can determine an abnormality in a recess provided on one surface of an optical member for a lighting device.
  • recesses are formed on one surface of a sheet-like base material made of resin or glass as an optical member for lighting devices (for example, an optical member used to extract light incident on a light guide plate to the outside of the light guide plate).
  • optical members are known.
  • Patent Document 1 discloses an optical member (single-sided illumination window 10) in which a concave portion 14a is provided on one surface of a transparent base material (light guide plate) 12 (for example, FIG. 1 of Patent Document 1 etc).
  • Patent Document 2 discloses that a light guide plate (for example, Patent Document A film (for example, a film (for example, A second film 212) in FIG. 21A of Patent Document 2 is disclosed.
  • Optical members such as those described above can be formed by various methods, such as forming recesses on the surface of a base material by embossing, or forming recesses on the surface of a resin base material using a mold with convex parts and then curing it. be done.
  • the recess has an inclined portion for total reflection of incident light from the light source.
  • the inclined portion is inclined at a predetermined angle with respect to the surface of the optical member.
  • the present invention has been made in order to solve the problems of the prior art as described above, and is an inspection method for an optical member that can determine abnormalities in a recess provided on one surface of an optical member for a lighting device.
  • An object of the present invention is to provide a method, an inspection device, and a manufacturing method.
  • the present invention provides a method for inspecting an optical member for an illumination device, which has a recessed portion on one surface, wherein the recessed portion has a cross section along the thickness direction of the optical member.
  • the optical member has an inclined part inclined at a predetermined inclination angle with respect to the surface of the optical member, is arranged on the other surface side of the optical member, is inclined in the same direction as the inclined part, and is normal to the other surface.
  • an abnormality determination step of extracting a pixel region having a pixel value equal to or higher than a predetermined threshold value in the captured image and determining whether the recess is abnormal based on the size of the area of the pixel region.
  • the optical member in the captured image generation step, is tilted in the same direction as the slope of the concave portion of the optical member, and the other surface side of the optical member (the surface side opposite to the one surface side where the concave portion is provided) is Light is irradiated onto the inclined part of the concave part from an illumination part having an optical axis inclined at a predetermined inclination angle with respect to the normal direction of the other surface.
  • An imaging unit having a visual axis along the normal direction of the surface captures an image of the light that is irradiated onto the inclined part and has passed through the optical member, thereby generating a captured image.
  • the abnormality determination step if a pixel region having a pixel value equal to or higher than a predetermined threshold value is extracted from the captured image by image processing the captured image, if a foreign object is mixed in the recess, It is thought that the area of the extracted pixel region will be smaller than if it were not mixed.
  • an abnormality in the recess is determined based on the size of the area of the pixel area (specifically, if the area of the pixel area is less than a predetermined value, it is determined that there is a possibility that foreign matter has entered the recess). Is possible. Furthermore, if the angle of inclination of the slope of the recess deviates from the design value, the light irradiated onto the slope of the recess will be refracted and propagated in a direction different from the direction assumed for the design value. I will do it.
  • the light irradiated to this inclined part is set so that it travels in the normal direction of one surface of the optical member (i.e., If the inclination angle of the optical axis of the illumination part is set so that the optical axis of the illumination part advances along the visual axis of the imaging part, if the inclination angle of the inclined part of the concave part deviates from the design value, Since the irradiated light travels in a direction away from the visual axis of the imaging unit, it is thought that the pixel value (luminance value) of the pixel area corresponding to the recess in the captured image becomes small (darker).
  • the abnormality determination step if a pixel region having a pixel value equal to or higher than a predetermined threshold value is extracted from the captured image by image processing the captured image, the inclination angle of the inclined portion of the recess will deviate from the design value.
  • the area of the extracted pixel region is considered to be smaller than that in the case where the design value is correct. Therefore, the abnormality of the recess is determined based on the size of the area of the pixel area (specifically, if the area of the pixel area is less than a predetermined value, the angle of inclination of the slope of the recess has deviated from the design value. It is possible to determine that there is a possibility.
  • a state in which foreign matter is mixed in the recess provided on one surface of an optical member for an illumination device, and a deviation in the inclination angle of the slope of the recess from the design value It is possible to determine that an abnormality has occurred in at least one of the states in which this occurs.
  • the illumination section emits parallel light.
  • the illumination unit that emits parallel light can be constructed by combining a light source and an optical system including a collimating lens, a parabolic mirror, etc. that converts the light emitted from the light source into parallel light.
  • the focal point of the imaging section is set at a position spaced apart from the one surface in the thickness direction of the optical member.
  • extraction can be performed using the preferred method described above. The difference between the area of the pixel region extracted when the recess is abnormal and the area of the pixel region extracted when the recess is abnormal is emphasized. Therefore, according to the above preferred method, it is possible to accurately determine the abnormality of the recess.
  • the inclination angle of the optical axis of the illumination unit is set such that the area of the pixel region of the captured image generated when the recess is normal (more preferably, (maximum value) according to the inclination angle of the inclined part of the recessed part.
  • the light emitted from the illumination section and irradiated onto the slope of the normal concave portion travels in a direction close to the normal direction of one surface of the optical member (i.e., the light emitted from the illumination section It can be expected that the object will proceed in a direction close to the visual axis of the object.
  • the inclination angle of the slope of the recess deviates from the design value, the light irradiated onto the slope of the recess will travel in a direction away from the visual axis of the imaging unit, and the pixels to be extracted will be It is considered that the area of the region tends to become smaller. Therefore, according to the above-described preferred method, it is possible to accurately determine an abnormality in the recess (particularly, a deviation in the angle of inclination of the slope of the recess).
  • a first pixel region having a pixel value greater than or equal to a predetermined first threshold value in the captured image is extracted, and a first pixel region having a pixel value greater than the first threshold value in the captured image is extracted.
  • a second pixel region having a pixel value equal to or greater than two thresholds is extracted, and a standard for the inclination angle of the inclined portion is determined based on the difference between the barycenter coordinates of the first pixel region and the barycenter coordinates of the second pixel region. Determine the direction of deviation from the angle.
  • barycentric coordinates means barycentric coordinates with respect to the inclination direction of the inclined part of the recess (the inclination direction of the optical axis of the illumination part).
  • the present invention is an apparatus for inspecting an optical member for a lighting device, which has a recessed portion on one surface, wherein the recessed portion is formed in a cross section along the thickness direction of the optical member. , has an inclined part inclined at a predetermined inclination angle with respect to the surface of the optical member, is arranged on the other surface side of the optical member, is inclined in the same direction as the inclined part, and is inclined in the direction of the other surface.
  • an illumination unit having an optical axis inclined at a predetermined inclination angle with respect to the linear direction; an imaging unit disposed on the one surface side and having a visual axis along the normal direction of the one surface; and the illumination unit.
  • the unit irradiates the inclined portion of the concave portion with light, and the imaging unit processes the captured image generated by capturing the light transmitted through the optical member. It is also provided as an inspection device for optical members, comprising: an image processing unit that extracts a pixel region having a pixel value equal to or higher than a threshold value, and determines whether there is an abnormality in the concave portion based on the size of the area of the pixel region. .
  • the present invention provides manufacturing of an optical member, which includes a manufacturing process of manufacturing the optical member, and an inspection process of inspecting the optical member manufactured in the manufacturing process using the testing method. Also provided as a method.
  • FIG. 1 is a diagram schematically showing a schematic configuration of an inspection device according to an embodiment of the present invention.
  • 1 is a diagram schematically showing an example of a schematic configuration of an illumination device using an optical member to be inspected according to the present invention. It is a figure explaining the shape of the recessed part of an optical member.
  • FIG. 3 is a cross-sectional view schematically showing an abnormality in a recessed portion of an optical member.
  • FIG. 7 is a diagram illustrating an example of a captured image (part of a captured image) that is generated when a foreign object is mixed in some of the recesses.
  • FIG. 6 is a diagram illustrating the effect of setting the focus of the imaging unit at a position separated from the surface of the optical member (that is, defocusing).
  • FIG. 7 is a diagram illustrating an example of the relationship between the inclination angle of the optical axis of the illumination section and the area of a bright portion in a captured image generated when the recess is normal.
  • FIG. 7 is a diagram illustrating an example of the relationship between the inclination angle of the inclined portion of the recess and the average pixel value of a generated captured image (a part of the captured image).
  • FIG. 6 is a diagram illustrating a procedure for determining a tilt angle shift direction, which is executed by an image processing unit.
  • FIG. 1 is a diagram schematically showing a schematic configuration of an inspection apparatus according to this embodiment.
  • FIG. 1(a) is a perspective view showing the overall configuration of the inspection device
  • FIG. 1(b) is a sectional view taken along the broken line A shown in FIG. 1(a).
  • illustration of the image processing section 3 shown in FIG. 1(a) is omitted.
  • the longitudinal direction (conveyance direction) of the optical member 10 is the X direction
  • the width direction (horizontal direction perpendicular to the longitudinal direction) of the optical member 10 is the Y direction
  • the thickness direction (vertical direction) of the optical member 10 is the Y direction. It is in the Z direction.
  • FIG. 1 is a diagram schematically showing a schematic configuration of an inspection apparatus according to this embodiment.
  • FIG. 1(a) is a perspective view showing the overall configuration of the inspection device
  • FIG. 1(b) is a sectional view taken along the broken line A shown in FIG. 1(a).
  • the inspection apparatus 100 inspects an optical member 10 for a lighting device, which has a plurality of recesses 11 on one surface (the upper surface in the example shown in FIG. 1) 10a. It is a device.
  • the long optical member 10 is inspected while being transported in the longitudinal direction (X direction) by the transport rolls R in a roll-to-roll manner.
  • the optical member 10 is shown as having a small number of relatively large recesses 11, but in reality, the optical member 10 has a large number of approximately 300,000 recesses per 100 mm square.
  • a recess 11 is provided.
  • the inspection apparatus 100 includes an illumination section 1 disposed on the other surface (the lower surface in the example shown in FIG.
  • the image processing unit 3 includes an image processing unit 3 that processes a captured image generated by the unit 1 irradiating light onto the recess 11 and the imaging unit 2 capturing the light transmitted through the optical member 10 .
  • the optical member 10 is a member used in a lighting device, and is made of a material that is highly transparent to the wavelength of light (for example, visible light having a wavelength of 380 nm or more and 780 nm or less) emitted by the lighting device.
  • the optical member 10 is made of, for example, acrylic resin such as polymethyl methacrylate (PMMA), polycarbonate (PC) resin, cycloolefin resin, vinyl chloride, polyethylene terephthalate, glass (for example, quartz glass, alkali-free glass, borosilicate glass, etc.). glass), etc.
  • the optical member 10 having the concave portion 11 on one surface 10a can be manufactured by a known method such as the method described in Japanese Patent Publication No.
  • the surface of a base film (for example, a PMMA film) is coated with a lacquer (for example, Fine Cure "RM-64" manufactured by Sanyo Chemical Industries, Ltd.), and the surface of the base film containing this lacquer is coated with a lacquer.
  • a lacquer for example, Fine Cure "RM-64" manufactured by Sanyo Chemical Industries, Ltd.
  • the elongated optical member 10 having the concave portion 11 on one surface 10a is manufactured (in this embodiment, after being further inspected by the inspection device 100), and is cut into a size according to the intended use. Used in lighting equipment.
  • FIG. 2 is a diagram schematically showing an example of a schematic configuration of an illumination device using the optical member 10 to be inspected by the inspection apparatus 100.
  • 2(a) is a cross-sectional view of the optical member 10 along the thickness direction (Z direction)
  • FIG. 2(b) is a plan view of the optical member 10 as seen from the thickness direction.
  • the lighting device 200 shown in FIG. 2 is a sheet-shaped lighting device that has two emission surfaces that emit light in opposite directions.
  • the illumination device 200 includes a first output surface (the lower surface in FIG.
  • the first light L1 is emitted to the lower side of FIG. 2(a), and the second light L2 is emitted to the upper side of FIG. 2(a).
  • the lighting device 200 includes a light guide member 201 and a light source 202.
  • the light guide member 201 includes a light receiving part that receives light emitted from the light source 202, a light guide layer 20 having a first main surface on the first exit surface side and a second main surface on the second exit surface side, and a plurality of light guide layers 20.
  • the optical member 10 of this embodiment has a recessed portion 11.
  • the optical member 10 is bonded to the second main surface of the light guide layer 20 with an adhesive layer 40, and the base material layer 30 and the optical member 10 are bonded with an adhesive layer 50.
  • the light guide layer 20 and the base layer 30 may be transparent substrates or films.
  • the light receiving portion of the light guide member 201 is, for example, the side surface of the light guide layer 20 on the light source 202 side.
  • Each of the plurality of recesses 11 includes a first slope portion 11a that totally reflects a part of the light propagating within the light guide layer 20 and directs it toward the first exit surface, and a second slope portion 11a on the opposite side of the first slope portion 11a. It has a triangular cross section with an inclined portion 11b.
  • the second light L2 emitted from the second exit surface is light that enters into the recess 11 from the first inclined portion 11a and passes through the recess 11.
  • the second light L2 passes through the interface between the recess 11 and the adhesive layer 50 or the second slope 11b. When the first light L1 and the second light L2 pass through the interface, they may be refracted according to the refractive index of the substance forming the interface.
  • the light guide member 201 emits the first light L1 having the first light distribution from the first output surface, and emits the first light L1 having the second light distribution from the second output surface. It is configured to emit the second light L2.
  • the first light distribution and the second light distribution can be controlled, for example, by adjusting the cross-sectional shape, planar shape, size, arrangement density, and distribution of the recess 11.
  • the inclination angle ⁇ a of the first inclined portion 11a is 10° or more and 70° or less.
  • the inclination angle ⁇ b of the second inclined portion 11b is greater than or equal to 50° and less than or equal to 100°.
  • the cross-sectional shape of the recess 11 is triangular as illustrated here, but is not limited to this, and may be trapezoidal or the like.
  • the light guide member 201 has, for example, a visible light transmittance of 60% or more and a haze value of less than 30%.
  • the visible light transmittance is preferably 70% or more, more preferably 80% or more.
  • the haze value is preferably less than 10%, more preferably 5% or less. If the light guide member 201 is configured to have a high visible light transmittance and a low haze value, objects (displays) can be seen through the light guide member 201.
  • the visible light transmittance and haze value can be measured using, for example, a haze meter (trade name: HM-150, manufactured by Murakami Color Research Institute).
  • the ratio of the area of the plurality of recesses 11 to the area of the light guide layer 20 is 1% or more 80 % or less, and the upper limit is more preferably 50% or less, further preferably 45% or less, and in order to obtain high transmittance and/or low haze value, 30% or less is preferable, and even more preferably 10% or less. , 5% or less is particularly preferred.
  • the occupied area ratio of the recesses 11 is 50%, a haze value of 30% can be obtained.
  • the occupied area ratio of the recess 11 may be uniform, or the occupied area ratio may be set to increase as the distance increases so that the brightness does not decrease even when the distance from the light source 202 increases. Good too. In order to mass-produce the optical member 10 using a roll-to-roll method, it is preferable that the occupied area ratio of the recesses 11 be uniform.
  • the plurality of recesses 11 are arranged, for example, in the light guiding direction of the light guiding member 201 (X direction, corresponding to the longitudinal direction of the optical member 10) and in the horizontal direction (Y (corresponding to the width direction of the optical member 10).
  • the size of the recess 11 (length L, width W: see FIGS. 3(a) and 3(b) described later)
  • the length L is preferably 10 ⁇ m or more and 500 ⁇ m or less
  • the width W is The thickness is preferably 1 ⁇ m or more and 100 ⁇ m or less.
  • the height H is preferably 1 ⁇ m or more and 100 ⁇ m or less.
  • a plurality of recesses 11 are arranged discretely in the light guide direction (X direction) of the light guide member 201 and in the direction (Y direction) orthogonal to the light guide direction.
  • the plurality of recesses 11 may be arranged discretely in the light guide direction (X direction) of the light guide member 201 and in the direction crossing the light guide direction.
  • the discrete arrangement of the recesses 11 is appropriately set according to the shape of the light guide layer 20, the required light distribution, and the like.
  • the discrete arrangement of the plurality of recesses 11 may or may not have periodicity (regularity) in at least one direction.
  • the plurality of recesses 11 be uniformly arranged.
  • a plurality of recesses 11 having substantially the same shape and a curved surface convex in plan view in the same direction are arranged in the light guide direction (X direction) of the light guide member 201. and are arranged discretely and periodically over the entire area in the direction (Y direction) perpendicular to the light guide direction.
  • the arrangement pitch Px in the X direction is preferably, for example, 10 ⁇ m or more and 500 ⁇ m or less
  • the arrangement pitch Py in the Y direction is, for example, preferably 10 ⁇ m or more and 500 ⁇ m or less.
  • the optical member 10 further includes recesses 11 arranged at a 1/2 pitch shift in each of the X direction and the Y direction.
  • the first inclined portion 11a when viewed from the normal direction to the first principal surface of the light guide layer 20, the first inclined portion 11a forms a convex curved surface toward the light source 202 side.
  • the light source 202 is, for example, an LED device, and a plurality of LED devices are arranged in the Y direction. Since the light emitted from each of the plurality of LED devices in the X direction has a spread in the Y direction, it is better for the first inclined portion 11a to form a convex curved surface on the light source 202 side.
  • the portion 11a acts uniformly on light.
  • the first inclined part 11a may be parallel to the Y direction.
  • the recesses 11 may be, for example, grooves (eg, triangular prisms) extending in the Y direction.
  • FIG. 3 is a diagram illustrating the shape of the recess 11.
  • FIG. 3(a) is a schematic cross-sectional view of the recess 11. Specifically, FIG. 3A shows a cross section passing through the center of the recess 11 where the dimension in the width W direction (X direction) is the largest among the cross sections of the recess 11 along the thickness direction of the optical member 10.
  • FIG. 3B is a schematic plan view of the recess 11
  • FIG. 3C is a schematic plan view showing a modification of the recess 11.
  • FIG. 3D is a diagram showing an example of the shape of the curved surface of the first inclined portion 11a of the recessed portion 11 in plan view.
  • the cross section of the recess 11 is, for example, triangular.
  • the inclination angle ⁇ a of the first inclined portion ⁇ a on the light source 202 side (the inclination angle with respect to the surface 10a of the optical member 10) is, for example, 10° or more and 70° or less. If the inclination angle ⁇ a is smaller than 10°, the controllability of light distribution may deteriorate, and the light extraction efficiency may also decrease. On the other hand, if the inclination angle ⁇ a exceeds 70°, it may become difficult to process the optical member 10, for example.
  • the inclination angle ⁇ b (the inclination angle with respect to the surface 10a of the optical member 10) of the second inclined portion 11b is, for example, 50° or more and 100° or less. If the inclination angle ⁇ b is smaller than 50°, stray light may occur in an unintended direction. On the other hand, if the inclination angle ⁇ b exceeds 100°, it may become difficult to process the optical member 10, for example.
  • the length L of the recess 11 is preferably 10 ⁇ m or more and 500 ⁇ m or less, and the width W of the recess 11 is preferably 1 ⁇ m or more and 100 ⁇ m or less.
  • the length L is, for example, twice or more the width W.
  • the height H of the recess 11 (see FIG. 3(a)) is preferably 1 ⁇ m or more and 100 ⁇ m or less. Note that, depending on the processing accuracy when manufacturing the optical member 10 having the concave portion 11 having the shape in plan view shown in FIG. 3(b), the concave portion 11 having the shape in plan view as shown in FIG. 3(c) is formed. Sometimes. Even in such a case, the length L and width W can characterize the shape of the recess 11 in plan view.
  • the plan view shape of the curved surface of the first inclined portion 11a that is convex toward the light source 202 side is represented, for example, in FIG. 3(d).
  • the example shown in FIG. 3(d) shows the shape of the first inclined portion 11a in plan view when the length L of the recessed portion 11 is 60 ⁇ m and the inclination angle ⁇ a of the first inclined portion 11a is 30°, 40°, and 49°. This is an example.
  • the width W of the recess 11 when the inclination angle ⁇ a is 30°, 40°, and 49° is approximately 13.9 ⁇ m, approximately 9.5 ⁇ m, and approximately 7.0 ⁇ m, respectively.
  • the curved surface shown in FIG. 3(d) can be approximated by, for example, a quartic curve.
  • FIG. 4 is a cross-sectional view schematically showing an abnormality in the recess 11.
  • 4(a) is a cross-sectional view of a normal recess 11
  • FIG. 4(b) is a cross-sectional view showing an abnormal state in which foreign matter M has entered the recess 11
  • FIG. ) is a cross-sectional view showing a state where an abnormality has occurred in which the inclination angle of the inclined portion of the recess 11 deviates from the design value.
  • FIG. 4C shows a state in which the designed shape of the inclined portion indicated by the broken line is deviated as indicated by the solid line.
  • the inspection apparatus 100 is an apparatus that inspects an abnormality in the inclination angle of the inclined part of the recess 11, particularly an abnormality in the inclination angle ⁇ a of the first inclined part 11a.
  • the inspection apparatus 100 includes the illumination section 1, the imaging section 2, and the image processing section 3. Each part will be specifically explained below.
  • the illumination part 1 is inclined in the same direction as the first inclined part 11a of the recessed part 11 of the optical member 10, and is tilted in a predetermined direction with respect to the normal direction of the other surface 10b of the optical member 10. It has an optical axis 1A inclined at an inclination angle ⁇ .
  • the optical axis 1A of the illumination part 1 is also inclined in the X direction (inclined around the Y direction). )are doing.
  • the illumination unit 1 of the present embodiment has a configuration capable of illuminating at least the entire width direction of the optical member 10 (the entire width direction of the location where the recessed portion 11 is provided), and as a preferred embodiment, it emits parallel light. It is configured.
  • the inclination angle ⁇ of the optical axis 1A of the illumination unit 1 is determined based on the pixel area of the captured image that is generated when the recess 11 is normal (the pixel area that has a pixel value equal to or higher than a predetermined threshold value).
  • the inclination angle of the first inclined part 11a of the recessed part 11 is adjusted such that the area of the first inclined part 11a of the recessed part 11 is equal to or larger than a predetermined threshold value (more preferably, reaches a maximum value). It is set according to ⁇ a (according to the design value of the inclination angle ⁇ a). For example, the inclination angle ⁇ of the optical axis 1A of the illumination unit 1 is set smaller than the inclination angle ⁇ a (design value of the inclination angle ⁇ a) of the first inclined portion 11a of the recess 11. When the designed value of the inclination angle ⁇ a is 49°, the inclination angle ⁇ is set to about 27°.
  • the inclination angle ⁇ of the optical axis 1A of the illumination part 1 is preferably 10° to 35° smaller than the inclination angle ⁇ a (design value of the inclination angle ⁇ a) of the first inclined part 11a of the recessed part 11, and 15° to It is more preferable that the angle is smaller by 30°, and still more preferably smaller by 17° to 27°.
  • the illumination unit 1 of this embodiment for example, a combination of an LED light source and a collimating lens can be used.
  • a spot light "HLV3-22BL-4S" manufactured by CCS is used as a light source
  • a lens "HL2- 50-P” can be used as the illumination section 1 by arranging a plurality of them in the Y direction so that the entire width direction of the optical member 10 can be illuminated.
  • the imaging unit 2 has a visual axis 2A along the normal direction (Z direction) of one surface 10a of the optical member 10.
  • the imaging section 2 in order to inspect the optical member 10 that is conveyed in the longitudinal direction (X direction) in a roll-to-roll manner, the imaging section 2 is configured to inspect the optical member 10 along the width direction (Y direction).
  • a line sensor is used in which a plurality of image pickup elements are arranged linearly and has a linear field of view extending in the width direction of the optical member 10.
  • the imaging unit 2 of this embodiment includes a telecentric lens in order to image only the light in the direction of the visual axis 2A to improve the accuracy of abnormality determination.
  • the resolution of the imaging unit 2 in the Y direction is set to, for example, several ⁇ m/pixel.
  • the imaging unit 2 captures an image of the light irradiated onto the optical member 10 by the illumination unit 1 and transmitted through the optical member 10, and the optical member 10 is conveyed in the longitudinal direction, thereby creating a two-dimensional (XY plane) captured image. generated.
  • a line sensor is used as the imaging unit 2, but the invention is not limited to this; a two-dimensional area camera with a high-speed shutter may be used as the imaging unit 2 to capture images at predetermined timings. It is also possible to generate a captured image.
  • FIG. 1 shows an example in which a single imaging section 2 is provided, in order to improve resolution, a configuration in which a plurality of imaging sections 2 are arranged in parallel in the width direction (Y direction) of the optical member 10 is also possible. It is also possible to adopt this method and combine the captured images obtained by the respective imaging units 2 to generate a captured image of the entire optical member 10 in the width direction.
  • the imaging unit 2 of this embodiment As a preferable aspect of the imaging unit 2 of this embodiment, as shown in FIG. It is set at a position separated by FL.
  • the focal point F of the imaging unit 2 is spaced away from the surface 10a of the optical member 10 in the direction approaching the imaging unit 2, but is set at a position away from the imaging unit 2. It is also possible to do so.
  • the focal point F of the imaging unit 2 By setting the focal point F of the imaging unit 2 at a position separated from the surface 10a of the optical member 10, as will be described later, the area of the pixel region (bright part) extracted when the recess 11 is normal and the recess The difference between the area of the pixel area (bright area) extracted when the area is abnormal is emphasized, and it is possible to accurately determine whether the recess 11 is abnormal.
  • the focal point F is set at a position distant from the surface 10a of the optical member 10, but the focus is not necessarily limited to this, and the focal point F is set at the surface 10a of the optical member 10 (i.e., It is also possible to set the separation distance FL to 0).
  • the image processing section 3 is electrically connected to the imaging section 2, and the illumination section 1 irradiates light onto the first inclined section 11a of the recessed section 11, and the imaging section 2 emits the light transmitted through the optical member 10.
  • Image processing is performed on the captured image generated by capturing the image.
  • the image processing unit 3 has, for example, a general-purpose computer installed with a program for executing image processing and determination processing, which will be described later.
  • the image processing unit 3 extracts a pixel area (bright area) having a pixel value equal to or higher than a predetermined threshold value in the captured image, and determines whether the recess is abnormal based on the size of the area of this bright area.
  • FIG. 5 is a diagram illustrating an example of a captured image (part of a captured image) that is generated when a foreign object is mixed in some of the recesses 11.
  • 5(a) is an example of a captured image generated when the separation distance FL of the focal point F of the imaging section 2 is 0 mm
  • FIG. 5(b) is an example of a captured image generated when the separation distance FL of the focal point F of the imaging section 2 is This is an example of a captured image generated when the distance is 0.5 mm.
  • the captured images shown in FIGS. 5A and 5B were obtained when the inclination angle ⁇ of the optical axis 1A of the illumination unit 1 was set to about 27°. Further, FIG.
  • FIG. 5(c) is an example of a captured image generated when a conventional normal transmission inspection is performed. Specifically, FIG. 5(c) is generated when the inclination angle ⁇ of the optical axis 1A of the illumination unit 1 is set to 0° and the separation distance FL of the focal point F of the imaging unit 2 is set to 0 mm. Corresponds to a captured image. As shown in FIGS. 5(a) and 5(b), the light irradiated onto the first inclined portion 11a of the recess 11 is blocked by the foreign object when the recess 11 contains foreign matter.
  • the pixel value (luminance value) of the pixel area corresponding to the concave portion 11 containing the foreign matter (the pixel area indicated by "abnormal part” in FIG. 5) is considered to be small (darker).
  • the image processing unit 3 performs image processing on the captured image to extract bright areas having pixel values equal to or higher than a predetermined threshold value in the captured image, it is possible to It is thought that the area of the extracted bright part will be smaller than when it is not mixed (the pixel area shown as "normal part” in FIG. 5).
  • the image processing unit 3 determines whether there is an abnormality in the recess 11 based on the size of the area of the bright part (specifically, if the area of the bright part is less than a predetermined value, it is determined that foreign matter has entered the recess 11). It is possible to determine that there is a possibility.
  • small area removal processing, expansion/contraction processing, etc. may be performed in inspection using the captured image, as necessary.
  • Various known image processing may be applied. In addition, as shown in FIG.
  • FIG. 6 is a diagram illustrating the effect of setting the focal point F of the imaging section 2 at a position separated from the surface 10a of the optical member 10 (that is, defocusing).
  • FIG. 6A shows the areas of bright parts of a normal part and an abnormal part (contamination of foreign matter) extracted in a captured image generated when defocusing is not performed (separation distance FL is set to 0 mm).
  • results shown in Figure 6 are obtained by quantizing the captured image with 8 bits (pixel value: 0 (darkest) to 255 (brightest)), and defining the pixel area with a pixel value of 250 or more as a bright area. This is the extracted result.
  • the vertical axis in FIG. 6 is the area calculated for each of the normal and abnormal areas at 10 locations, and the average value thereof is plotted.
  • the difference between the area of the area (data plotted with " ⁇ " in Figure 6) and the area of the bright area extracted when the recess 11 is abnormal (data plotted with " ⁇ ” in Figure 6) is emphasized. . Therefore, by defocusing the imaging unit 2, it is possible to accurately determine whether there is an abnormality in the recessed portion 11 based on the size of the area of the bright portion.
  • FIG. 3 is a diagram illustrating an example of the relationship between the bright area and the area of a bright portion in a captured image. As shown in FIG. 7, the area of the bright portion reaches its maximum value when the inclination angle ⁇ is around 27°. Therefore, as described above, when the inclination angle ⁇ a of the first inclined portion 11a is 49°, it is preferable that the inclination angle ⁇ of the optical axis 1A of the illumination unit 1 is set to about 27°.
  • FIG. 8 is a diagram illustrating an example of the relationship between the inclination angle ⁇ a of the first inclined portion 11a of the recessed portion 11 and the average pixel value of a generated captured image (part of the captured image).
  • the vertical axis of FIG. 8 is a plot of average pixel values for all pixel regions of a part of the captured image shown in FIG.
  • the more the inclination angle ⁇ a of the first inclination part 11a deviates from the design value ( ⁇ a 49°), the more the inclination angle ⁇ a of the first inclination part 11a differs from the direction assumed for the design value (Z direction, the direction of the visual axis 2A of the imaging unit 2). It will proceed by refracting. Therefore, as shown in FIG. 8, it is considered that the more the inclination angle ⁇ a of the first inclined portion 11a deviates from the design value, the smaller the pixel value of the pixel region corresponding to the concave portion in the captured image becomes.
  • the image processing unit 3 determines whether the recess 11 is abnormal based on the size of the area of the pixel region (specifically, if the area of the bright part is less than or equal to a predetermined value, the inclination of the first slope 11a of the recess 11 is determined).
  • the image processing unit 3 extracts a pixel area (bright area) having a pixel value equal to or higher than a predetermined threshold value in the captured image, and based on the size of the area of this bright area, the image processing unit 3 extracts the pixel area (bright area) in the captured image. It is possible to determine abnormalities (contamination of foreign matter and deviation of the inclination angle ⁇ a). However, the determination performed by the image processing unit 3 is not limited to this, and it may be configured to determine the direction of deviation of the inclination angle ⁇ a of the first inclined portion 11a from the reference angle (design value). .
  • FIG. 9 is a diagram illustrating a procedure for determining the direction of deviation of the inclination angle ⁇ a, which is executed by the image processing unit 3.
  • the image processing unit 3 extracts a first pixel region having a pixel value greater than or equal to a predetermined first threshold value in the captured image, and extracts a first pixel region having a pixel value greater than the first threshold value in the captured image.
  • a second pixel area having a pixel value greater than or equal to a second threshold is extracted.
  • the first threshold is set to a value within the range of 60 to 128, for example, when the captured image is quantized with 8 bits. Note that in FIG. 9, only the outline of the first pixel region to be extracted is illustrated for convenience.
  • the second threshold value is set to 250, for example, when the captured image is quantized with 8 bits.
  • the bright area used for the abnormality determination described above corresponds to the second pixel area.
  • the image processing unit 3 calculates the barycenter coordinates of the first pixel region and the barycenter coordinates of the second pixel region.
  • the barycenter coordinates refer to the barycenter coordinates in the inclination direction of the first inclined portion 11a of the recessed portion 11 (the inclination direction of the optical axis 1A of the illumination unit 1), and therefore, in this embodiment, they are the barycenter coordinates in the X direction. More specifically, the image processing unit 3 calculates an average value Gx1 of the barycenter coordinates of the entire first pixel region and an average value Gx2 of the barycenter coordinates of the entire second pixel region, which are extracted from the captured image.
  • the image processing unit 3 determines the reference angle (design value) of the inclination angle ⁇ a of the first inclination part 11a based on the difference (Gx1-Gx2) between Gx1 and Gx2 (based on the sign of the difference between Gx1 and Gx2). Determine the direction of deviation from.
  • the difference between Gx1 and Gx2 is a negative value.
  • the present invention is not limited to this. It is also possible to inspect the optical member 10 cut to a length while keeping it still, using a two-dimensional area camera as the imaging unit 2.
  • the direction of the length L of the recess 11 provided in the optical member 10 matches the direction (Y direction) perpendicular to the longitudinal direction of the optical member 10 ( (see FIG. 2(b)), the direction of the length L of the recess 11 may coincide with the longitudinal direction (X direction) of the optical member 10.
  • the optical axis 1A of the illumination section 1 is also inclined in the Y direction (inclined around the X direction). All you have to do is arrange it accordingly.
  • the abnormality in the inclination angle of the inclination part of the recessed part 11 has been explained by taking as an example the case where an abnormality in the inclination angle ⁇ a of the first inclination part 11a is inspected, but the present invention is limited to this. It's not a thing.
  • the inclination angle ⁇ of the optical axis 1A of the illumination part 1 may be set so that the second inclined part 11b is irradiated with light. .
  • the light is set so that the first inclination part 11a is irradiated with light.
  • An illumination section with an axis inclination angle set and an illumination section with an optical axis inclination angle set so that light is irradiated to the second inclination section 11b are provided separately, and a certain amount of light is emitted from each illumination section. It is possible to adopt a mode in which the light is emitted while being switched alternately every cycle, and the light emitted from each illumination section is imaged by a common imaging section 2. Alternatively, it is also conceivable to adopt a mode in which an imaging section used for each illumination section is provided separately.

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Abstract

Le problème décrit par la présente invention est de fournir un procédé d'inspection d'un élément optique, par lequel une condition anormale peut être déterminée à une partie d'évidement disposée sur une surface de l'élément optique pour un illuminateur. À cet effet, l'invention concerne un procédé d'inspection d'élément optique (10) pour un illuminateur, l'élément optique (10) comportant une partie d'évidement (11) sur une surface (10a), le procédé comprenant les étapes suivantes : la génération d'une image capturée en émettant de la lumière vers une partie inclinée (11a) de la partie d'évidement à partir d'une unité d'éclairage (1), qui est disposée sur l'autre surface (10b) de l'élément optique (10), qui est inclinée dans la même direction que la partie inclinée (11a) et dont l'axe optique (1A) est incliné à un angle prédéterminé θ par rapport à la direction normale de l'autre surface, et la capture d'une image de la lumière, qui est émise vers la partie inclinée et qui traverse l'élément optique, par une unité d'imagerie (2) qui est disposée d'un côté de la surface et dont l'axe visuel (2A) suit la direction normale de la surface ; et l'extraction d'une zone de pixels, qui présente une valeur de pixel égale ou supérieure à une valeur seuil prédéterminée dans l'image capturée, par traitement de l'image capturée et la détermination d'une condition anormale dans la partie d'évidement sur la base des dimensions de la zone de pixel.
PCT/JP2023/011357 2022-03-24 2023-03-23 Procédé d'inspection d'élément optique, dispositif d'inspection et procédé de fabrication WO2023182390A1 (fr)

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JP2022-049149 2022-03-24
JP2022049149A JP2023142309A (ja) 2022-03-24 2022-03-24 光学部材の検査方法、検査装置及び製造方法

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11281590A (ja) * 1998-03-26 1999-10-15 Mitsubishi Rayon Co Ltd プリズムシートの欠陥検査方法
JP2012122753A (ja) * 2010-12-06 2012-06-28 Fujifilm Corp レンズシートの欠陥検査装置、欠陥検査方法及び製造装置
JP2016099314A (ja) * 2014-11-26 2016-05-30 大日本印刷株式会社 検査システムおよび検査方法
JP2018059772A (ja) * 2016-10-04 2018-04-12 オムロン株式会社 シート検査装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11281590A (ja) * 1998-03-26 1999-10-15 Mitsubishi Rayon Co Ltd プリズムシートの欠陥検査方法
JP2012122753A (ja) * 2010-12-06 2012-06-28 Fujifilm Corp レンズシートの欠陥検査装置、欠陥検査方法及び製造装置
JP2016099314A (ja) * 2014-11-26 2016-05-30 大日本印刷株式会社 検査システムおよび検査方法
JP2018059772A (ja) * 2016-10-04 2018-04-12 オムロン株式会社 シート検査装置

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