Visual inspection device and its use

Abstract

To properly detect defects in the appearance of translucent cups. [Solution] In an appearance inspection device 10 comprising an imaging unit (1) and two illumination units (2, 3), the two illumination units (2, 3) are arranged such that their illumination surfaces are parallel to the side surface of the translucent cup C in the Z direction. When viewed from the Z direction, illumination unit (2) is arranged such that its illumination optical axis (Ax2) makes an angle of 70°±10° with respect to the imaging optical axis (Ax1), and illumination unit (3) is arranged such that its illumination optical axis (Ax3) makes an angle of -70°±10° with respect to the imaging optical axis (Ax1).

Description

Technical Field

[0001] The present invention relates to an appearance inspection device and its use.

Background Art

[0002] Conventionally, a technique for inspecting the appearance of a cylindrical article using an imaging device such as a camera and a lighting device has been known.

[0003] For example, Patent Document 1 discloses a technique for inspecting a shape defect generated in the top curl portion of a paper cup using an imaging unit, a transmission light source, and a reflection light source. Further, Patent Document 2 discloses a technique for inspecting a surface defect of a metal material having a cylindrical outer shape using an imaging unit and a pair of diffused illumination units.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional technology as described above, when the inspection target is a translucent cup, the appearance of the translucent cup cannot be sufficiently inspected, and there are cases where appearance defects cannot be detected.

[0006] One aspect of the present invention aims to realize an appearance inspection device that can appropriately detect defects in the appearance of a translucent cup and its use.

Means for Solving the Problems

[0007] To solve the above problems, an appearance inspection apparatus according to one aspect of the present invention is an appearance inspection apparatus for inspecting the appearance of a translucent cup, comprising: an imaging unit whose imaging optical axis is arranged perpendicular to the side surface of the translucent cup; and first and second illumination units that illuminate the imaging area of ​​the imaging unit on the side surface of the translucent cup, wherein the first and second illumination units are arranged such that their illumination surfaces are parallel to the side surface of the translucent cup in the axial direction of the translucent cup, and, viewed from the axial direction of the translucent cup, the first illumination unit is arranged such that its first illumination optical axis makes an angle of 70°±10° with respect to the imaging optical axis, and the second illumination unit is arranged such that its second illumination optical axis makes an angle of -70°±10° with respect to the imaging optical axis.

[0008] Furthermore, in order to solve the above problems, an appearance inspection method according to one aspect of the present invention is an appearance inspection method for inspecting the appearance of a translucent cup using an appearance inspection apparatus comprising an imaging unit and first and second illumination units, the method comprising: an imaging step in which the imaging unit is positioned so that the imaging optical axis is perpendicular to the side surface of the translucent cup and the imaging unit is used to image the side surface of the translucent cup; and an illumination step in which the first and second illumination units are used to illuminate the imaging area of ​​the imaging unit on the side surface of the translucent cup, wherein in the illumination step, the first and second illumination units are positioned so that the illumination surfaces of the first and second illumination units are parallel to the side surface of the translucent cup in the axial direction of the translucent cup, the first illumination unit is positioned so that the first illumination optical axis is at an angle of 70°±10° with respect to the imaging optical axis when viewed from the axial direction of the translucent cup, and the second illumination unit is positioned so that the second illumination optical axis is at an angle of -70°±10° with respect to the imaging optical axis. [Effects of the Invention]

[0009] According to one aspect of the present invention, defects in the appearance of a translucent cup can be appropriately detected. [Brief explanation of the drawing]

[0010] [Figure 1]This is a schematic diagram showing the general configuration of an appearance inspection device according to an embodiment of the present invention, as viewed from the Z direction. [Figure 2] This is a schematic diagram showing the general configuration of an appearance inspection device according to an embodiment of the present invention, as viewed from the X direction. [Modes for carrying out the invention]

[0011] One embodiment of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic and patent documents mentioned herein are incorporated as references herein. Furthermore, unless otherwise specified herein, "A to B" representing a numerical range means "A or greater (including A and greater than A) and B or less (including B and less than B)." Furthermore, each drawing is shown for clarity when referred to in conjunction with the following description and is not necessarily drawn to a fixed scale.

[0012] (Visual inspection device according to this embodiment) Figure 1 is a schematic diagram illustrating the general configuration of the visual inspection apparatus 10 according to this embodiment as viewed from the Z direction. Figure 2 is a schematic diagram illustrating the general configuration of the visual inspection apparatus 10 according to this embodiment as viewed from the X direction.

[0013] The appearance inspection device 10 according to this embodiment is a device for inspecting the appearance of a translucent cup C. Here, in Figures 1 and 2, the direction in which the axis O of the translucent cup C extends is defined as the Z direction (up and down direction), and in the Z direction, one side is defined as the Za side and the other side as the Zb side. Also, in the appearance inspection device 10 as viewed from the Za side (the appearance inspection device 10 shown in Figure 1), the imaging direction of the imaging unit 1, i.e., the direction in which the imaging optical axis Ax1 extends, is defined as the Y direction, and in the Y direction, one side is defined as the Ya side and the other side as the Yb side. Also, the direction perpendicular to both the X direction and the Z direction is defined as the X direction, and in the X direction, one side is defined as the Xa side and the other side as the Xb side. For example, if the Z direction is the vertical direction (up and down direction), the Y direction is the front-back direction and the X direction is the left-right direction. In this case, Za is the upper side, Zb is the lower side, Ya is the front side, Yb is the back side, Xa is the right side, and Xb is the left side.

[0014] As shown in Figures 1 and 2, the visual inspection device 10 comprises an imaging unit 1, an illumination unit 2 (first illumination unit) and an illumination unit 3 (second illumination unit), and a rotating table 4.

[0015] The imaging unit 1 is positioned such that its imaging optical axis Ax1 is perpendicular to the side surface of the translucent cup C. In other words, the imaging unit 1 is positioned so that the direction of the imaging optical axis Ax1 coincides with the direction of the normal to the side surface of the translucent cup C. More specifically, when viewed from the X direction, if θ4 is the angle between the Y direction and the imaging optical axis Ax1 of the imaging unit 1, the imaging unit 1 is positioned so that the angle of inclination of the side surface of the translucent cup C with respect to the Z direction coincides with angle θ4.

[0016] The imaging unit 1 is composed of, for example, a solid-state image sensor such as a CCD or CMOS sensor and an optical system such as a lens. The imaging unit 1 may be, for example, an area camera that uses a solid-state image sensor having a two-dimensional imaging area as its sensor. Preferably, the imaging unit 1 is a line scan camera that uses a solid-state image sensor having a one-dimensional imaging area as its sensor.

[0017] Illumination units 2 and 3 illuminate the imaging area of ​​the imaging unit 1 on the side of the translucent cup C. As shown in Figure 1, when viewed from the Z direction, illumination units 2 and 3 are positioned symmetrically with respect to the imaging optical axis Ax1 of the imaging unit 1. Furthermore, both the imaging unit 1 and illumination units 2 and 3 are positioned on the Yb side with respect to the translucent cup C. The illumination light emitted from illumination unit 2 is directed in a direction inclined by an angle θ2 with respect to the imaging optical axis Ax1 of the imaging unit 1, as shown in Figure 1. Similarly, the illumination light emitted from illumination unit 3 is directed in a direction inclined by an angle θ3 with respect to the imaging optical axis Ax1 of the imaging unit 1. Angle θ2 can be said to be the angle between the imaging optical axis Ax1 of the imaging unit 1 and the illumination optical axis Ax2 of illumination unit 2 when viewed from the Z direction. Angle θ3 can be said to be the angle between the imaging optical axis Ax1 of the imaging unit 1 and the illumination optical axis Ax3 of illumination unit 3 when viewed from the Z direction.

[0018] As shown in Figure 2, when viewed from the X direction, the illumination unit 2(3) is inclined at the same angle θ4 with respect to the Y direction as the imaging unit 1 is inclined at. Here, angle θ4 coincides with the inclination angle of the side surface of the translucent cup C with respect to the Z direction. Therefore, illumination units 2 and 3 are positioned such that their illumination surfaces are parallel to the side surface of the translucent cup C in the Z direction. In other words, in a cross-section along the Z direction, the illumination surface of illumination unit 2(3) is parallel to the side surface of the translucent cup C.

[0019] To uniformly illuminate the curved sides of the translucent cup C, the illumination light emitted from illumination units 2 and 3 is preferably diffused light. Illumination units 2 and 3 are particularly preferably bar illuminations. Conventional bar illuminations can be used for illumination units 2 and 3. Bar illumination is a rod-shaped lighting fixture in which light sources are arranged in a straight line. For example, bar illumination has a bar-shaped LED substrate with multiple LEDs incorporated as a light source, and a light diffuser plate diffuses the light emitted from the bar-shaped LED substrate. From the viewpoint of uniformly illuminating the entire length of the translucent cup C, it is preferable that the length of the bar illuminations as illumination units 2 and 3 in the Z direction is the same as or greater than the height of the translucent cup C.

[0020] The turntable 4 rotates the translucent cup C around the axis O of the translucent cup C. Specifically, the turntable 4 rotates the translucent cup C with the axis O as the rotation center while supporting the translucent cup C so that the distance between the imaging unit 1 and the side surface of the translucent cup C does not change. The turntable 4 rotates the translucent cup C intermittently or continuously by a predetermined angle in a certain outer peripheral direction. Finally, the turntable 4 rotates the translucent cup C by 360° or more. By the turntable 4, the imaging unit 1 can sequentially capture images of a predetermined inspection region (hereinafter referred to as a unit inspection region) on the side surface of the translucent cup C over the entire circumference of the outer peripheral surface of the translucent cup C.

[0021] A series of processes of the appearance inspection apparatus 10 will be described. Each time the imaging unit 1 images a unit inspection area, the appearance inspection apparatus 10 acquires an image of the unit inspection area from the imaging unit 1. Next, the appearance inspection apparatus 10 sequentially accumulates the images of the unit inspection areas acquired from the imaging unit 1. Finally, when the turntable 4 finishes rotating the translucent cup C through a full circle, the appearance inspection apparatus 10 accumulates the images of a plurality of unit inspection areas imaged by the imaging unit 1 over the entire circumference of the outer peripheral surface of the translucent cup C. The appearance inspection apparatus 10 performs image processing on the accumulated images of the plurality of unit inspection areas, combines the images of these plurality of unit inspection areas in the order of imaging time, and thereby generates an image of an inspection area (hereinafter referred to as a full-circumference inspection area) over the entire circumference of the outer peripheral surface of the translucent cup C. The appearance inspection apparatus 10 performs image processing based on pixel information such as the luminance and chromaticity of each pixel of the generated full-circumference inspection area image, and detects characteristic portions within the full-circumference inspection area image. Here, the characteristic portions correspond to defective portions of the translucent cup C. Examples of defective portions of the translucent cup C include air bubbles inside the translucent cup C, traces of air bubbles flowing on the inner and outer surfaces of the translucent cup C, foreign matter inside the translucent cup C, voids inside the translucent cup C caused by short shots (insufficient resin), chips, holes, and the like. These defective portions are particularly seen in the translucent cup C manufactured by press molding. Further, compared with the normal portions within the side surface of the translucent cup C, the above-mentioned defective portions have different states such as luminance or color tone. The appearance inspection apparatus 10 detects the defective portions of the translucent cup C by such a characteristic portion detection process. Thereafter, the appearance inspection apparatus 10 causes the display unit to display the defective portion detection result of the translucent cup C, such as the image of the full-circumference inspection area.

[0022] The above-described series of processes of the appearance inspection apparatus 10 can be realized by hardware and software of a data processing apparatus such as a microcomputer, a personal computer, an image processing system, a programmable sequence controller, or the like. Further, the image processing for the full-circumference inspection area image may be any process that can appropriately detect the above-described defective portions, and conventionally known image processing can be adopted. Examples of such image processing include filtering, image correction, feature extraction, and the like.

[0023] Furthermore, the detection process for feature portions corresponding to the aforementioned defects within the image of the full-circumference inspection area is not particularly limited, and conventionally known techniques can be applied. For example, a reference image of the full-circumference inspection area is stored in the visual inspection device 10, the reference image is compared with the image to be inspected, and feature portions are detected based on the comparison result.

[0024] The inventors diligently studied the arrangement conditions of the imaging unit 1 and illumination units 2 and 3 so that all defective parts of the translucent cup C described above can be detected by generating an image of the entire circumference inspection area in a single pass. More specifically, they diligently studied the conditions under which the color of the image of the entire circumference inspection area is uniform and the contrast between the defective parts and the normal parts is clear. As a result, they found that by setting angles θ2 and θ3 to specific ranges in the configurations shown in Figures 1 and 2, the color of the image of the entire circumference inspection area is uniform and the contrast between the defective parts and the normal parts is clear, leading to the appearance inspection device 10 according to this embodiment. That is, in the appearance inspection device 10 according to this embodiment, (1) the illumination unit 2 is arranged such that the illumination optical axis Ax2 (first illumination optical axis) makes an angle θ2 of 70°±10° with respect to the imaging optical axis Ax1, and (2) the illumination unit 3 is arranged such that the illumination optical axis Ax3 (second illumination optical axis) makes an angle θ3 of -70°±10° with respect to the imaging optical axis Ax1.

[0025] In other words, in the visual inspection device 10, the angle θ2 between the illumination optical axis Ax2 and the imaging optical axis Ax1 is 70°±10°, and the angle θ3 between the illumination optical axis Ax3 and the imaging optical axis Ax1 is -70°±10°. For angles θ2 and θ3, the angle direction tilting toward the illumination unit 2 side is defined as "+" with respect to the imaging optical axis Ax1, and the angle direction tilting toward the illumination unit 3 side is defined as "-".

[0026] The visual inspection device 10 has the configuration shown in Figures 1 and 2, and with angles θ2 being 70°±10° and θ3 being -70°±10°, it can generate an image of the entire inspection area with uniform color and clear contrast between defective and normal areas. As a result, all defective parts of the translucent cup C can be detected with a single generation of the full-circumference inspection area image, effectively detecting defects in the appearance of the translucent cup C.

[0027] As long as the above effects are achieved, angles θ2 and θ3 can be arbitrarily set within the above numerical range. From the viewpoint of improving the above effects, angle θ2 is preferably 70°±5°, and particularly preferably 70°. Also, angle θ3 is preferably -70°±5°, and particularly preferably -70°. The lighting units 2 and 3 may be configured to rotate within the above numerical ranges of angles θ2 and θ3.

[0028] Furthermore, as shown in Figure 1, when viewed from the Z direction, the illumination units 2 and 3 were positioned symmetrically with respect to the imaging optical axis Ax1 of the imaging unit 1, that is, the absolute values ​​of angle θ2 and angle θ3 were the same. However, as long as the above effect is achieved, within the above numerical range, angles θ2 and θ3 may be the same or different in absolute value. In other words, the illumination units 2 and 3 may be positioned asymmetrically with respect to the imaging optical axis Ax1 of the imaging unit 1. Preferably, the visual inspection device 10 has the configuration shown in Figure 1, in which the illumination units 2 and 3 are positioned symmetrically with respect to the imaging optical axis Ax1 of the imaging unit 1.

[0029] The distance D1 between the imaging unit 1 and the side of the translucent cup C can be set as appropriate, as long as the above effects are achieved. For example, the distance D1 is preferably 100mm to 150mm, and more preferably 120mm to 140mm. For example, the distance D1 is 130mm.

[0030] Furthermore, the distance D2 between the imaging area of ​​the imaging unit 1 and the illumination unit 2 on the side of the translucent cup C can be set as appropriate, as long as the above effects are achieved. For example, the distance D2 is preferably 50mm to 60mm, and more preferably 53mm to 57mm. As a more specific example, the distance D2 is 55mm. Similarly, the distance D3 between the imaging area of ​​the imaging unit 1 and the illumination unit 3 on the side of the translucent cup C can also be set as appropriate, as long as the above effects are achieved. For example, the distance D3 is preferably 50mm to 60mm, and more preferably 53mm to 57mm. As a more specific example, the distance D3 is 55mm.

[0031] (Visual inspection method according to this embodiment) The appearance inspection method according to this embodiment is a method using the appearance inspection apparatus 10 shown in Figures 1 and 2. That is, the appearance inspection method according to this embodiment is a method for inspecting the appearance of a translucent cup C using an appearance inspection apparatus 10 equipped with an imaging unit 1 and illumination units 2 and 3. The appearance inspection method according to this embodiment includes an imaging step and an illumination step. In the imaging step, the imaging unit 1 is positioned so that the imaging optical axis Ax1 is perpendicular to the side surface of the translucent cup C, and the imaging unit 1 images the side surface of the translucent cup C. In the illumination step of the appearance inspection method according to this embodiment, the illumination units 2 and 3 are positioned so that in the Z direction, the illumination surfaces of the illumination units 2 and 3 are parallel to the side surface of the translucent cup C. Furthermore, in the illumination process, the illumination unit 2 is positioned such that the illumination optical axis Ax2 is at an angle of 70° ± 10° with respect to the imaging optical axis Ax1 when viewed from the Z direction, and the illumination unit 3 is positioned such that the illumination optical axis Ax3 is at an angle of -70° ± 10° with respect to the imaging optical axis Ax1. This achieves the same effect as the visual inspection device 10. In the visual inspection method according to this embodiment, the various processes, including the imaging process and the illumination process, are the same as the series of processes performed in the visual inspection device 10, so their explanation is omitted.

[0032] (Method for manufacturing a translucent cup according to this embodiment) The method for manufacturing a translucent cup according to this embodiment includes the visual inspection method according to this embodiment as one step. A method for manufacturing a translucent cup to which the visual inspection method according to this embodiment can be applied can employ conventionally known techniques. For example, a method can be given in which a translucent cup manufactured using a conventionally known technique is inspected using the visual inspection method according to this embodiment to confirm its quality. In particular, it is preferable that the manufacturing method is a method for manufacturing a translucent cup by press molding of a thermoplastic resin composition.

[0033] (Translucent cup) In this embodiment, the translucent cup only needs to be made of a translucent material, and conventionally known materials can be used. Here, "translucent" material means a material that partially transmits visible light, and refers to a material with a visible light transmittance of 50% to 80%.

[0034] The translucent cup is preferably made of resin. The resin constituting the translucent cup is preferably made of a biodegradable resin as the base resin. Furthermore, the biodegradable resin is not particularly limited, but examples include polyhydroxyalkanoic acid resins, polylactic acid, polyglycolic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, polybutylene succinate terephthalate, polycaprolactone, and the like. Among these, the biodegradable resin is preferably a polyhydroxyalkanoic acid resin (hereinafter sometimes referred to as PHA resin). In this specification, "PHA resin" is a general term for polymers having hydroxyalkanoic acid as the monomer unit.

[0035] Particularly preferred is the biodegradable resin, among PHA resins, a poly(3-hydroxyalkanoate) resin (hereinafter sometimes referred to as P3HA resin). In this specification, "P3HA resin" refers to a 3-hydroxyalkanoic acid repeating unit represented by the general formula: [-CHR-CH2-CO-O-] (wherein R is C n H 2n+1It is a polyhydroxyalkanoate containing an alkyl group represented by , where n is an integer between 1 and 15 (inclusive), as a repeating unit.

[0036] More specifically, P3HA resins preferably contain 3-hydroxybutyrate (3HB) units. Examples of P3HA resins containing 3HB units include poly(3-hydroxybutyrate) (P3HB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HB3HV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), and poly(3-hydroxybutyrate-co-3-hydroxydecanoate).

[0037] As for P3HA resins, P3HA resins produced by microorganisms (microbially produced P3HA resins) are preferred. Microbially produced P3HA resins are usually composed only of D-isomers (R-isomers) of polyhydroxyalkanoate monomer units. Among microbially produced P3HA resins, P3HB, P3HB3HH, P3HB3HV, P3HB3HV3HH, and P3HB4HB are preferred due to their ease of industrial production, and P3HB, P3HB3HH, P3HB3HV, and P3HB4HB are more preferred.

[0038] The microorganisms that produce microbially produced P3HA resins are not particularly limited as long as they are microorganisms capable of producing P3HA resins. For example, the first P3HB-producing bacterium was Bacillus megaterium, discovered in 1925, and other examples include natural microorganisms such as Cupriavidus necator (formerly classified as Alcaligenes eutrophus, Ralstonia eutropha) and Alcaligenes latus. It is known that P3HB accumulates within the cells of these microorganisms.

[0039] Furthermore, known microorganisms that produce copolymers of hydroxybutyrate and other hydroxyalkanoates include Aeromonas caviae, which produces P3HB3HV and P3HB3HH, and Alcaligenes eutrophus, which produces P3HB4HB. In particular, with respect to P3HB3HH, Alcaligenes eutrophus AC32 strain (FERM BP-6038) (T.Fukui, Y.Doi, J.Bateriol., 179, p4821-4830 (1997)), into which genes of the P3HA resin synthase group have been introduced, are more preferred in order to increase the productivity of P3HB3HH. Microbial cells that have accumulated P3HB3HH in their cells by culturing these microorganisms under appropriate conditions are used. In addition to the above, genetically modified microorganisms into which various P3HA resin synthesis-related genes can be introduced can be used, depending on the P3HA resin to be produced, or the culture conditions, including the type of substrate, can be optimized.

[0040] Furthermore, the P3HA resin contains at least one copolymer of 3HB units and other hydroxyalkanoate units, and the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin are preferably 90.0 to 99.0 mol%, more preferably 91.0 to 98.5 mol%, more preferably 92.0 to 98.5 mol%, and even more preferably 93.0 to 98.0 mol%, of the total repeating units (100 mol%).

[0041] When the composition ratio of 3HB repeating units is 90.0 mol% or higher, the rigidity of the P3HA resin is further improved, the crystallization rate is increased, burrs are reduced, and productivity tends to improve. On the other hand, when the composition ratio of 3HB repeating units is 99.0 mol% or lower, the melting point is below the thermal decomposition temperature, enabling stable and continuous production. The monomer composition ratio of P3HA resin can be measured by gas chromatography, etc. (see, for example, International Publication No. 2014 / 020838).

[0042] The molecular weight of the P3HA resin is not particularly limited, as long as it exhibits substantially sufficient physical properties for the intended application. The weight-average molecular weight range of the P3HA resin is preferably 100,000 to 1,000,000, more preferably 150,000 to 700,000, even more preferably 200,000 to 500,000, and particularly preferably 250,000 to 450,000. A weight-average molecular weight of 100,000 or more provides adequate mechanical strength. Furthermore, a molecular weight of 1,000,000 or less suppresses the increase in melt viscosity and provides excellent moldability.

[0043] The weight-average molecular weight can be determined using gel permeation chromatography (GPC) (Shodex GPC-101, Showa Denko Corporation), with a polystyrene gel column (Shodex K-804, Showa Denko Corporation) and chloroform as the mobile phase, expressed as the molecular weight in polystyrene equivalent. Calibration curves are created using polystyrene with weight-average molecular weights of 31,400, 197,000, 668,000, and 1,920,000. Any column suitable for measuring the aforementioned molecular weights can be used in the GPC.

[0044] The resin constituting the translucent cup may include a second P3HA-based resin in addition to the P3HA-based resin. The second P3HA-based resin contains at least one copolymer of 3HB units and other hydroxyalkanoate units, and the 3HB units in the poly(3-hydroxyalkanoate)-based resin are preferably 65.0 to 90.0 mol%, more preferably 68.0 to 88.0 mol%, and even more preferably 70.0 to 85.0 mol% of the total repeating units (100 mol%). Further inclusion of the second P3HA-based resin in the resin constituting the translucent cup results in superior toughness of the molded product.

[0045] The second P3HA-based resin is not particularly limited, as long as it is different from the aforementioned P3HA-based resin. Examples of the second P3HA-based resin include the resins exemplified above as P3HA-based resins.

[0046] The content of the second P3HA resin is not particularly limited, but is preferably 50 parts by weight or less, more preferably 45 parts by weight or less, and even more preferably 40 parts by weight or less, per 100 parts by weight of the total P3HA resin. The lower limit of the content of the second P3HA resin is not particularly limited and may be 0 parts by weight. The P3HA resin described above can be used as the second P3HA resin. In this specification, "total P3HA resin" refers to all P3HA resin contained in the resin constituting the translucent cup.

[0047] The resin constituting the translucent cup may contain other resins besides P3HA-based resins, as long as the effects of the present invention are not impaired. Examples of such other resins include aliphatic polyester resins such as polybutylene succinate adipate, polybutylene succinate, polycaprolactone, and polylactic acid, and aliphatic aromatic polyester resins such as polybutylene adipate terephthalate, polybutylene sebatate terephthalate, and polybutylene azelate terephthalate. The other resin may consist of only one type or two or more types.

[0048] The content of the other resins is not particularly limited, but is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, per 100 parts by weight of the total P3HA resin. Even more preferably 30 parts by weight or less. The lower limit of the content of the other resins is not particularly limited and may be 0 parts by weight.

[0049] The resin constituting the translucent cup does not necessarily have to contain inorganic fillers, but it is preferable that it further contains inorganic fillers. The inclusion of inorganic fillers in the molten resin composition improves the crystallization rate, resulting in effects such as reduced burrs and improved production cycles.

[0050] The inorganic filler is not particularly limited, but examples include talc, diatomaceous earth, white clay, clay, calcium carbonate, manganese carbonate, magnesium carbonate, barium sulfate, mica, silica, alumina, zircon, iron oxide, zinc oxide, titanium oxide, silicon nitride, boron nitride, aluminum nitride, silicon carbide, graphite, carbon black, ferrite, graphite, quartz, glass fiber, and glass particles. These may be used individually or in combination of two or more types.

[0051] The inorganic filler content is, for example, 0 to 60 parts by weight, preferably 5 to 50 parts by weight, more preferably 10 to 40 parts by weight, and particularly preferably 15 to 35 parts by weight, per 100 parts by weight of the total P3HA resin. When the inorganic filler content is within the above range, it is possible to achieve both a sufficient crystallization rate and toughness.

[0052] Furthermore, the resin constituting the translucent cup may contain additives that can be used together with the P3HA-based resin, to the extent that they do not impair the effects of the present invention. Examples of such additives include colorants such as pigments and dyes, odor absorbers such as activated carbon and zeolites, fragrances such as vanillin and dextrin, plasticizers, antioxidants, weather-resistant modifiers, ultraviolet absorbers, crystal nucleating agents, lubricants, mold release agents, water repellents, antibacterial agents, and sliding properties modifiers. Only one type of additive may be included, or two or more types may be included. The content of these additives can be appropriately determined by those skilled in the art depending on the intended use.

[0053] (summary) One embodiment of the present invention is as follows: <1> An appearance inspection apparatus for inspecting the appearance of a translucent cup, comprising: an imaging unit whose imaging optical axis is arranged perpendicular to the side surface of the translucent cup; and first and second illumination units for illuminating the imaging area of ​​the imaging unit on the side surface of the translucent cup, wherein the first and second illumination units are arranged such that their illumination surfaces are parallel to the side surface of the translucent cup in the axial direction of the translucent cup, and, viewed from the axial direction of the translucent cup, the first illumination unit is arranged such that its first illumination optical axis forms an angle of 70°±10° with respect to the imaging optical axis, and the second illumination unit is arranged such that its second illumination optical axis forms an angle of -70°±10° with respect to the imaging optical axis. <2> The aforementioned imaging unit is a line scan camera. <1> A visual inspection device. <3> The first and second lighting units are bar lighting. <1> or <2> A visual inspection device. <4> An appearance inspection method for inspecting the appearance of a translucent cup using an appearance inspection apparatus comprising an imaging unit and first and second illumination units, comprising: an imaging step of arranging the imaging unit so that the imaging optical axis is perpendicular to the side surface of the translucent cup and imaging the side surface of the translucent cup with the imaging unit; and an illumination step of illuminating the imaging area of ​​the imaging unit on the side surface of the translucent cup with the first and second illumination units, wherein in the illumination step, the first and second illumination units are arranged so that the illumination surfaces of the first and second illumination units are parallel to the side surface of the translucent cup in the axial direction of the translucent cup, the first illumination unit is arranged so that the illumination optical axis of the first illumination unit is at an angle of 70°±10° with respect to the imaging optical axis when viewed from the axial direction of the translucent cup, and the second illumination unit is arranged so that the illumination optical axis of the second illumination unit is at an angle of -70°±10° with respect to the imaging optical axis. <5> <4> A method for manufacturing translucent cups, which includes a visual inspection method as one of the steps. [Examples]

[0054] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0055] <Inspection targets and equipment used> Test subject: translucent cup Equipment used: Bar lighting x 2 LNSP2-500SW (manufactured by CCS Corporation) Line scan camera TL-16KTCL (manufactured by Takenaka System Equipment Co., Ltd.) Rotating platform OSMS-60YAW (manufactured by Sigma Koki Co., Ltd.).

[0056] (Example 1) An image of the entire circumference inspection area of ​​a translucent cup was generated using the visual inspection apparatus 10 shown in Figures 1 and 2. The line scan camera was used as the imaging unit 1, the two bar lights were used as the illumination units 2 and 3, and the turntable 4 was the turntable described above.

[0057] Specifically, a translucent cup was first placed on a rotating platform, and a line scan camera was positioned perpendicular to the side of the translucent cup. The distance D1 between the line scan camera and the side of the translucent cup was set to 130 mm.

[0058] Next, one bar light was positioned such that, viewed from above, the angle θ2 of the illumination optical axis with respect to the imaging optical axis of the line scan camera was 70°, and the other bar light was positioned such that the angle θ3 of the illumination optical axis with respect to the imaging optical axis of the line scan camera was -70°. The distance D2 between the imaging area of ​​the line scan camera on the side of the translucent cup and one bar light was set to 130 mm. The distance D3 between the imaging area of ​​the line scan camera on the side of the translucent cup and the other bar light was also set to 130 mm.

[0059] Then, while illuminating the side of the translucent cup with the bar lighting arranged in this manner, the rotating platform was rotated, and the side of the translucent cup was sequentially imaged with a line scan camera to obtain images of the unit inspection area. Image processing was performed on the obtained images of multiple unit inspection areas, and these images of multiple unit inspection areas were combined in order of acquisition time, thereby generating an image of the outer perimeter inspection area of ​​the translucent cup.

[0060] The generated images of the outer perimeter inspection area were visually evaluated for color uniformity and the contrast difference between defective and normal areas.

[0061] (Example 2) An image of the outer perimeter inspection area of ​​a translucent cup was generated by the same operation as in Example 1, except that one bar light was rotated within a numerical range of angle θ2 of 70°±5° when viewed from above, and the other bar light was rotated within a numerical range of angle θ3 of -70°±5°.

[0062] The generated images of the outer perimeter inspection area were visually evaluated for color uniformity and the contrast difference between defective and normal areas.

[0063] (Example 3) An image of the outer perimeter inspection area of ​​a translucent cup was generated by the same operation as in Example 1, except that one bar light was rotated within a numerical range of angle θ2 of 70°±10° when viewed from above, and the other bar light was rotated within a numerical range of angle θ3 of -70°±10°.

[0064] The generated images of the outer perimeter inspection area were visually evaluated for color uniformity and the contrast difference between defective and normal areas.

[0065] (Comparative Example 1) An image of the outer perimeter inspection area of ​​a translucent cup was generated by the same operation as in Example 1, except that one bar light was rotated within a numerical range of angle θ2 of 70°±15° when viewed from above, and the other bar light was rotated within a numerical range of angle θ3 of -70°±15°.

[0066] The generated images of the outer perimeter inspection area were visually evaluated for color uniformity and the contrast difference between defective and normal areas.

[0067] (Evaluation results) Of Examples 1 to 3, the image of the outer perimeter inspection area of ​​the translucent cup in Example 1 showed the best color uniformity and contrast difference between defective and normal areas. Next, the image of the outer perimeter inspection area of ​​the translucent cup in Example 2 also showed good color uniformity and contrast difference between defective and normal areas. For the image of the outer perimeter inspection area of ​​the translucent cup in Example 3, the color uniformity and contrast difference between defective and normal areas were within acceptable limits for inspecting the defective areas on the side of the translucent cup.

[0068] On the other hand, the image of the outer perimeter inspection area of ​​the translucent cup in Comparative Example 1 lacked sufficient color uniformity and contrast between the defective and normal areas when inspecting the defective parts on the side of the translucent cup.

[0069] As described above, it was found that practical inspection of defects on the side of a translucent cup is possible if the angle θ2 is within the range of 70°±10° and the angle θ3 is within the range of -70°±10°. [Industrial applicability]

[0070] The present invention can be suitably used in the field of manufacturing press-molded articles using thermoplastic resins, particularly P3HA-based resins, and in other fields. [Explanation of Symbols]

[0071] 1. Imaging Unit 2. Lighting Section (First Lighting Section) 3. Lighting Section (Second Lighting Section) 4 Rotating Platforms 10 Visual Inspection Device Ax1 imaging optical axis Ax2 illumination axis (first illumination axis) Ax3 illumination axis (second illumination axis)

Claims

1. An appearance inspection device for inspecting the appearance of a translucent cup, An imaging unit is positioned such that the imaging optical axis is perpendicular to the side surface of the translucent cup, The device comprises first and second illumination units that illuminate the imaging area of ​​the imaging unit on the side surface of the translucent cup, The first and second illumination units are arranged such that their illumination surfaces are parallel to the side surface of the translucent cup in the axial direction of the translucent cup. Viewed from the axial direction of the aforementioned translucent cup, The first illumination unit is positioned such that the first illumination optical axis forms an angle of 70° ± 10° with respect to the imaging optical axis. The second illumination unit is an appearance inspection device in which the second illumination optical axis is positioned at an angle of -70° ± 10° with respect to the imaging optical axis.

2. The appearance inspection apparatus according to claim 1, wherein the imaging unit is a line scan camera.

3. The appearance inspection apparatus according to claim 1 or 2, wherein the first and second lighting units are bar lights.

4. An appearance inspection method for inspecting the appearance of a translucent cup using an appearance inspection apparatus comprising an imaging unit and first and second illumination units, The imaging step involves positioning the imaging unit so that the imaging optical axis is perpendicular to the side surface of the translucent cup, and imaging the side surface of the translucent cup with the imaging unit, The process includes an illumination step of illuminating the imaging area of ​​the imaging unit on the side surface of the translucent cup with the first and second illumination units, In the aforementioned lighting process, The first and second illumination units are positioned such that, in the axial direction of the translucent cup, the illumination surfaces of the first and second illumination units are parallel to the side surface of the translucent cup. Viewed from the axial direction of the aforementioned translucent cup, The first illumination unit is positioned such that the first illumination optical axis is at an angle of 70° ± 10° with respect to the imaging optical axis. An appearance inspection method in which the second illumination unit is positioned such that the second illumination optical axis is at an angle of -70° ± 10° with respect to the imaging optical axis.

5. A method for manufacturing a translucent cup, comprising the visual inspection method described in claim 4 as one step.

Images