Inspection method, inspection device, manufacturing method, manufacturing device, and optical wavelength conversion sheet, backlight device, liquid crystal panel, and liquid crystal display device

Abstract

Provided is a method of inspecting an optical wavelength conversion sheet, an inspection device, a manufacturing method, a manufacturing device, an optical wavelength conversion sheet, a backlight device, a liquid crystal panel, and a liquid crystal display device, which can improve inspection accuracy. The inspection is performed using an image captured by irradiating a blue light from the back side of an optical wavelength conversion sheet (10) having a quantum dot layer (20) including quantum dots that emit red light and green light by receiving the blue light, and capturing an image from the surface side using a camera (80). A filter (82) that transmits red light and green light while cutting off blue light is provided between the camera (80) and the optical wavelength conversion sheet (10).

Description

Technical Field

[0001] The present invention relates to a method, apparatus, manufacturing method, and manufacturing apparatus for inspecting an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band having a peak wavelength different from that of the first wavelength band by receiving light of the first wavelength band, as well as an optical wavelength conversion sheet, a backlight device, a liquid crystal panel, and a liquid crystal display device. Background Technology

[0002] Quantum dots (QDs, also known as quantum dots, etc.) are known as light wavelength converters that emit light in a second wavelength band that has a different peak wavelength from the light in the first wavelength band by receiving light in the first wavelength band. Quantum dots are used, for example, as light wavelength conversion sheets having a quantum dot layer (light wavelength conversion layer) containing quantum dots in the backlight unit of a liquid crystal display device. In the case of a backlight unit for a liquid crystal display device, for example, the light wavelength conversion sheet is illuminated from the back side by blue illumination light. This light wavelength conversion sheet contains quantum dots that emit red light (light in the second wavelength band) by receiving blue light (light in the first wavelength band) and quantum dots that emit green light (light in the second wavelength band) by receiving blue light. Thus, white light containing the blue illumination light and the red and green light generated by converting the wavelength of the illumination light is obtained.

[0003] Furthermore, as a method for inspecting a wavelength conversion sheet that includes a phosphor as a wavelength converter, the following patent document 1 is known. In the following patent document 1, an excitation light is irradiated onto a wavelength conversion sheet that includes two phosphors (wavelength converters), and light in a wavelength band where the difference in luminescence intensity of the two phosphors generated by the excitation light is 25% or more is selectively received and inspected.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-052868 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] However, in Patent Document 1, there is a problem that requires considerable effort, for example. When inspecting a light wavelength conversion sheet containing three types of phosphors, such as a phosphor that emits blue light, a phosphor that emits red light, and a phosphor that emits green light, it is necessary to inspect it according to the type of light wavelength conversion sheet, for example, to inspect it for receiving blue light, to inspect it for receiving red light, and to inspect it for receiving green light.

[0009] Furthermore, to prevent this problem, when inspecting by receiving white light containing blue, red, and green light (while simultaneously inspecting blue, red, and green light), there is a risk of decreased inspection accuracy. In particular, if the backlight unit's wavelength conversion sheet generates white light containing illumination light (e.g., blue light) and light generated by receiving illumination light (e.g., red and green light), and the processes for generating each color of light are different, then even if each color is inspected under the same conditions, correct inspection results cannot be obtained.

[0010] The present invention was made in view of the above background, and its object is to provide an inspection method, inspection apparatus, manufacturing method, manufacturing apparatus, as well as an optical wavelength conversion sheet, a backlight device, a liquid crystal panel, and a liquid crystal display device that can improve the inspection accuracy without effort.

[0011] means for solving technical problems

[0012] To achieve the above objective, the inspection method for the optical wavelength conversion sheet of the present invention is an inspection method for an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band having a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band. The method includes: an illumination step in which illumination light containing light of the first wavelength band is irradiated toward the back side of the optical wavelength conversion sheet; an imaging step in which an image is captured from the surface side of the optical wavelength conversion sheet; and an imaging wavelength selection step in which, between the illumination step and the imaging step, light from the optical wavelength conversion sheet is separated into light of the first wavelength band and light other than the first wavelength band, and light other than the first wavelength band is selected as imaging light and emitted into the imaging step.

[0013] On the optical wavelength conversion layer, multiple storage chambers are formed by using partitions perpendicular to the layer, and the optical wavelength converter can be sealed in each storage chamber.

[0014] A support layer can be set on the back side of the optical wavelength conversion layer.

[0015] The back of the support layer can be protected by a back protective film.

[0016] A transparent optical layer can be set on the surface side of the wavelength conversion layer.

[0017] The surface of the optical layer can be protected by covering it with a surface protective film.

[0018] The first wavelength band can be included within the wavelength band of visible light.

[0019] It can have a primary inspection process, which includes an illumination process, an imaging process, and an imaging wavelength selection process; and a secondary inspection process, which includes a secondary illumination process in which illumination light including light in the first wavelength band and light in the second wavelength band is directed toward the back of the light wavelength conversion sheet, and a secondary imaging process in which the light conversion sheet is photographed from the surface side of the light wavelength conversion sheet.

[0020] It can have a comparison process that compares a primary camera image taken during a first inspection process with a secondary camera image taken during a second inspection process.

[0021] Furthermore, in order to achieve the above-mentioned objective, the inspection device for the optical wavelength conversion sheet of the present invention is an inspection device for an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band that has a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band. The device includes: an illumination mechanism that illuminates the back of the optical wavelength conversion sheet with illumination light containing the light of the first wavelength band; an image camera mechanism that captures an image of the optical wavelength conversion sheet from the surface side of the optical wavelength conversion sheet; and an image wavelength selection mechanism that separates the light of the first wavelength band and the light other than the first wavelength band between the optical wavelength conversion sheet and the image camera mechanism, and selects the light other than the first wavelength band as the image light and emits it toward the image camera mechanism.

[0022] Furthermore, in order to achieve the above-mentioned objective, the method for manufacturing the optical wavelength conversion sheet of the present invention is a method for manufacturing an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band that has a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band. The method includes: a forming step for forming an optical wavelength conversion layer; and an inspection step for inspecting the optical wavelength conversion sheet on which the optical wavelength conversion layer is formed. The inspection step includes: an irradiation step for irradiating the back of the optical wavelength conversion sheet with illumination light containing light of the first wavelength band; an imaging step for imaging the optical wavelength conversion sheet from the surface side of the optical wavelength conversion sheet; and an imaging wavelength selection step for separating light of the first wavelength band and light other than the first wavelength band between the optical wavelength conversion sheet and the imaging step, and selecting the light other than the first wavelength band as imaging light and emitting it to the imaging step.

[0023] Furthermore, in order to achieve the above-mentioned objective, the manufacturing apparatus for the optical wavelength conversion sheet of the present invention is an apparatus for manufacturing an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band that has a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band. The apparatus includes: a forming apparatus for forming the optical wavelength conversion layer; and an inspection apparatus for inspecting the optical wavelength conversion sheet on which the optical wavelength conversion layer is formed. The inspection apparatus includes: an illumination mechanism for illuminating the back side of the optical wavelength conversion sheet with illumination light containing the light of the first wavelength band; an image camera mechanism for imaging the optical wavelength conversion sheet from the surface side of the optical wavelength conversion sheet; and an image wavelength selection mechanism for separating light of the first wavelength band and light other than the first wavelength band between the optical wavelength conversion sheet and the image camera mechanism, and selecting the light other than the first wavelength band as the image light and emitting it toward the image camera mechanism.

[0024] Furthermore, the manufacturing method of the optical wavelength conversion sheet of the present invention is a method for manufacturing an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band with a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band. This method includes: a forming step to form an optical wavelength conversion layer; an inspection step to inspect the optical wavelength conversion sheet on which the optical wavelength conversion layer is formed; and a removal step to remove defective portions detected in the inspection step from the portion used as a product. The inspection step includes: an irradiation step to irradiate the back of the optical wavelength conversion sheet with illumination light containing the light of the first wavelength band; and an imaging step to capture an image of the optical wavelength conversion sheet from the surface side. The process includes: a replacement of the optical transducer; a wavelength selection process, in which light is separated into light in the first wavelength band and light other than the first wavelength band between the optical transducer and the imaging process, and light other than the first wavelength band is selected as imaging light and emitted into the imaging process; a defect candidate detection process, in which candidates for defect locations are detected using the imaging image obtained in the imaging process; and a defect location determination process, in which the location to be detected as a defect location is determined from the candidates for defect locations. In the defect location determination process, when illumination light containing light in the first wavelength band is shone from the back side of the optical transducer and observed from the surface side, the location whose brightness is different from the surrounding area is determined by visual observation to be a defect location.

[0025] In the defect location identification process, it is preferable to regard the area whose brightness is 135% or more greater than that of the surrounding area as the area that is determined by visual observation to have a different brightness from the surrounding area, and thus identify it as a defect location.

[0026] Furthermore, the optical wavelength conversion sheet of the present invention is manufactured by the optical wavelength conversion sheet manufacturing method described above.

[0027] Furthermore, the optical wavelength conversion sheet of the present invention is an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band that has a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band. In this case, when illumination light containing light of the first wavelength band is irradiated from the back side and observed from the surface side, the portion whose brightness is less than 135% of the brightness of the surrounding portion is defined as a normal portion, and the portion whose brightness is 135% or more of the brightness of the surrounding portion is defined as a defective portion. The defective portions are removed from the portion used as a product, thereby constituting only the normal portion.

[0028] Furthermore, the optical wavelength conversion sheet of the present invention is an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band that has a peak wavelength different from that of the first wavelength band by receiving light of the first wavelength band. In this case, when illumination light containing light of the first wavelength band is irradiated from the back side and observed from the surface side, areas with a brightness difference of less than 400 μm from the surrounding area are designated as normal areas, and areas with a brightness difference of 400 μm or more from the surrounding area are designated as defective areas. Defective areas are removed from the area used as a product, thereby constituting only normal areas.

[0029] Furthermore, the optical wavelength conversion sheet of the present invention is an optical wavelength conversion sheet having an optical wavelength conversion layer comprising an optical wavelength conversion body that emits light of a second wavelength band that has a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band. In this case, when illumination light containing light of the first wavelength band is irradiated from the back side and observed from the surface side, portions with brightness less than 135% relative to the brightness of the surrounding portions and size less than 400 μm are defined as normal portions, and portions with brightness greater than 135% relative to the brightness of the surrounding portions and size greater than 400 μm are defined as defect portions. Defect portions are removed from the portion used as a product, thereby constituting only normal portions.

[0030] Preferably, a support layer is provided on the back side of the optical wavelength conversion layer.

[0031] Preferably, multiple storage compartments are formed on the optical wavelength conversion layer by using partitions perpendicular to the layer.

[0032] Furthermore, the backlight device of the liquid crystal panel of the present invention includes the aforementioned wavelength conversion sheet.

[0033] In addition, the liquid crystal panel of the present invention includes the aforementioned wavelength conversion sheet.

[0034] Furthermore, the liquid crystal display device of the present invention includes the aforementioned wavelength conversion sheet, liquid crystal panel, and backlight device.

[0035] Invention Effects

[0036] According to the present invention, the inspection accuracy of optical wavelength conversion sheets can be improved effortlessly. Attached Figure Description

[0037] Figure 1 This is a cross-sectional view of the optical wavelength conversion plate.

[0038] Figure 2 This is an explanatory diagram showing the structure of the adjacent room.

[0039] Figure 3 This is an explanatory diagram of the equipment used to manufacture optical wavelength conversion sheets.

[0040] Figure 4 This is an explanatory diagram of the inspection device (single inspection device).

[0041] Figure 5 It is an explanatory diagram of the camera image and spectrum.

[0042] Figure 6 It is an explanatory diagram of the camera image and spectrum.

[0043] Figure 7 It is an explanatory diagram of the camera image and spectrum.

[0044] Figure 8 This is an explanatory diagram of the equipment used to manufacture optical wavelength conversion sheets.

[0045] Figure 9 This is an explanatory diagram of the secondary inspection device.

[0046] Figure 10 This is an explanatory diagram of the camera image.

[0047] Figure 11 This is an explanatory diagram of the camera image.

[0048] Figure 12 This is an explanatory diagram of the camera image.

[0049] Figure 13 This is an explanatory diagram showing the verification results of the inspection device.

[0050] Figure 14 This is an explanatory diagram representing a photographic image and a magnified image of the photographic image.

[0051] Figure 15 This is an explanatory diagram showing the analysis results of the camera image.

[0052] Figure 16 This is an explanatory diagram showing the results of three inspections.

[0053] Figure 17 This is an explanatory diagram showing the results of three inspections. Detailed Implementation

[0054] [First Implementation]

[0055] Figure 1 The optical wavelength conversion sheet 10 of the present invention is shown. The optical wavelength conversion sheet 10 is manufactured using a manufacturing apparatus 50 (optical wavelength conversion sheet manufacturing apparatus) described later (see reference). Figure 3 Manufacturing, for example, backlight units used in liquid crystal display devices.

[0056] A quantum dot layer 20 (wavelength conversion layer) is formed between the support layer 12 and the optical layer 14 in the wavelength conversion sheet 10. Furthermore, the wavelength conversion sheet 10 is covered on its surface (upper surface) by a laminated film 22 (surface-side protective film) and on its back surface (lower surface) by a laminated film 24 (back-side protective film). The laminated films 22 and 24 are formed of a transparent material. The laminated films 22 and 24 are provided to protect the wavelength conversion sheet 10 until it is installed in the backlight unit of a liquid crystal display device or otherwise used. When the wavelength conversion sheet 10 is used, these films are peeled off from the wavelength conversion sheet 10.

[0057] In addition, when the light wavelength conversion sheet 10 is used in the backlight unit of a liquid crystal display device, a backlight that emits light with a peak wavelength (hereinafter referred to as blue light) in a wavelength band (first wavelength band) in the range of 400 nm or more and less than 500 nm is disposed on the back side (lower surface side) of the support layer 12, and a liquid crystal panel encapsulated therein is disposed on the surface side (upper surface side) of the optical layer 14.

[0058] In this embodiment, the support layer 12 is a sheet-like component with a thickness of approximately 60 μm that has the function of reflecting light with a wavelength of 500 nm to 800 nm. Similarly, in this embodiment, the optical layer 14 is a sheet-like component with a thickness of approximately 150 μm that has a prism formed on its surface side and has the function of diffusing light. Furthermore, this embodiment is not limited to the support layer 12; it is sufficient that the support layer 12 has the function of transmitting light from the backlight of the liquid crystal display device (blue light in this embodiment). The optical layer 14 is sufficient that it has the function of transmitting visible light (including the aforementioned blue light, red light, and white light described later, as well as green light). Moreover, this embodiment is not limited to the thickness of the support layer 12, the optical layer 14, and the quantum dot layer 20 described later; the thicknesses can be freely set.

[0059] The quantum dot layer 20 has a thickness of approximately 30 μm. Within the quantum dot layer 20, multiple storage chambers 32 are formed by partitions 30 perpendicular to the layer, and these storage chambers 32 are arranged longitudinally and transversely along the layer (parallel to the layer). Furthermore, in this embodiment, a honeycomb structure is formed by the partitions 30. That is, as... Figure 2As shown, when the quantum dot layer 20 is viewed from a direction perpendicular to the layer, it becomes a structure in which multiple hexagonal storage chambers 32, formed by being separated by partitions 30, are arranged without gaps along the layer.

[0060] return Figure 1 Each storage chamber 32 contains a light emitter 34 (wavelength converter) containing quantum dots (wavelength converters). In this embodiment, two types of quantum dots are used: quantum dots that emit light (hereinafter referred to as red light) with a peak wavelength in a wavelength band (second wavelength band) ranging from 600 nm to 680 nm by receiving blue light, and quantum dots that emit light (hereinafter referred to as green light) with a peak wavelength in a wavelength band (second wavelength band) ranging from 500 nm to less than 600 nm by receiving blue light. That is, the light emitter 34 contains two types of quantum dots. Therefore, when the wavelength conversion sheet 10 (quantum dot layer 20) is illuminated with blue light, white light containing blue light for illumination, red light emitted from the two types of quantum dots that have received the illumination light (blue light), and green light can be obtained.

[0061] Furthermore, in this embodiment, an example was described where the light in the first wavelength band is blue light and the light in the second wavelength band is red and green light. However, the present invention is not limited to this; for example, the light in the first wavelength band could be red light and the light in the second wavelength band could be blue and green light. Of course, the light in the first wavelength band could also be green light and the light in the second wavelength band could be red and blue light. However, the peak difference between the light in the first wavelength band and the light in the second wavelength band is preferably in the range of 10 nm to 400 nm, and more preferably in the range of 100 to 400 nm.

[0062] The optical wavelength conversion plate 10 with the above structure is inspected by the inspection device 70 described later (see reference). Figure 3 , Figure 4 Manufactured by conducting inspections, thus each 1m 2 The number of defective areas is one or less. In addition, a defective area refers to an area where, when the light wavelength conversion sheet 10 is illuminated from the back side and an image is taken from the surface side, the brightness of the captured image differs from that of the surrounding area by more than 7%, and the size is more than 100 μm.

[0063] Figure 3 The manufacturing apparatus 50 (optical wavelength conversion sheet manufacturing apparatus) for manufacturing the aforementioned optical wavelength conversion sheet 10 is shown. The manufacturing apparatus 50 includes: a forming apparatus 52 (forming process) for forming a quantum dot layer 20; and an inspection apparatus 70 (inspection process) for inspecting the optical wavelength conversion sheet 10 on which the quantum dot layer 20 is formed.

[0064] The forming apparatus 52 includes a first feed roller 54, a first casting die 56, a shaping roller 58, a second casting die 60, a second feed roller 62, and a layering roller 64. An optical sheet 14a constituting the optical layer 14 is wound on the first feed roller 54, and the first feed roller 54 feeds the wound optical sheet 14a toward the shaping roller 58 via conveying rollers 54a and 54b. Furthermore, in this embodiment, the surface (on...) Figure 3 In the process, the optical sheet 14a, on the side opposite to the first casting mold 56, is fed out from the first feed roller 54 with a laminated film 22 attached to it. However, the laminated film 22 can also be attached to the surface of the optical sheet 14a further downstream than the first feed roller 54.

[0065] The first casting mold 56 is disposed between the conveying rollers 54a and 54b, and the optical sheet 14a passes under the first casting mold 56 with its back side facing the first casting mold 56. The first casting mold 56 ejects transparent curable (ultraviolet curable in this embodiment) resin from an ejector that is formed along the width direction of the optical sheet 14a to the back side of the optical sheet 14a to form a cast film 20a.

[0066] The shaping roller 58 forms grooves on its circumferential surface for shaping the partition 30. An optical sheet 14a with a cast film 20a is pressed against the shaping roller 58 by the cast film 20a and deformed into the shape of the partition 30. Furthermore, in this state, the cast film 20a is cured by irradiation with ultraviolet light from the ultraviolet light source 58a. This forms the partition 30. The optical sheet 14a with the partition 30 formed is then conveyed toward the layering roller 64 via conveyor rollers 58b and 58c.

[0067] The second casting mold 60 is positioned between the conveying rollers 58b and 58c. The optical sheet 14a passes under the second casting mold 60 with its back side, where the partition walls 30 are formed, facing the second casting mold 60. The second casting mold 60 ejects the light-emitting element 34 from an outlet formed elongated in the width direction of the optical sheet 14a. As a result, the space between the partition walls 30 (i.e., the receiving chamber 32) is filled with the light-emitting element 34. In this embodiment, the light-emitting element 34 is a curable (in this embodiment, ultraviolet curable) composition that combines the two types of quantum dots described above.

[0068] A second feed roller 62 is provided on the back side of the optical sheet 14a. A support sheet 12a constituting the support layer 12 is wound on the second feed roller 62, and the second feed roller 62 feeds the wound support sheet 12a toward the layering roller 64 via the conveying roller 62a. In this embodiment, the support sheet 12a with a laminated film 24 attached to its back side (the side opposite to the optical sheet 14a) is fed out from the second feed roller 62, but it is also possible to attach the laminated film 24 to the back side of the support sheet 12a further downstream than the second feed roller 62.

[0069] The support sheet 12a, fed from the second delivery roller 62, is disposed on the back side (the side with the partition wall 30) of the optical sheet 14a on the downstream side of the second casting die 60, and is integrally pressed against the layering roller 64 with the optical sheet 14a. In this state, ultraviolet light is irradiated from the ultraviolet light source 64a, and the support sheet 12a and the optical sheet 14a are bonded together. Thus, a quantum dot layer 20 (wavelength conversion sheet 10) is formed. The wavelength conversion sheet 10 with the quantum dot layer 20 formed is conveyed to the inspection device 70 (inspection device for wavelength conversion sheets) via the transport roller 64b.

[0070] like Figure 4 As shown, the inspection device 70 includes an irradiation mechanism 72 (irradiation process), a camera mechanism 74 (camera process), and a camera wavelength selection mechanism 76 (camera wavelength selection process), and is used to inspect (detect) the defective parts described later.

[0071] The illumination mechanism 72 includes a light source 78 that emits blue light, the same as the backlight of the liquid crystal display device. The light source 78 is disposed on the back side of the light wavelength conversion sheet 10. Figure 4 The back of the light wavelength conversion sheet 10 is illuminated with illumination light (blue light) on the lower side of the light wavelength conversion sheet 10. In this embodiment, the illumination light is vertically illuminated on the back of the light wavelength conversion sheet 10.

[0072] The camera mechanism 74 includes a camera 80. The camera 80 is located on the surface side of the light wavelength conversion plate 10. Figure 4 The camera 80 is positioned so that its photographic optical axis is aligned with the illumination optical axis from the light source 78, and it takes pictures of the light wavelength conversion plate 10. As described above, in this embodiment, the camera 80 is configured to illuminate the light wavelength conversion plate 10 perpendicularly, so that it takes pictures of the light wavelength conversion plate 10 from a vertical direction.

[0073] The imaging wavelength selection mechanism 76 has the function of separating light from the light wavelength conversion plate 10 into light in a first wavelength band and light other than the first wavelength band between the light wavelength conversion plate 10 and the camera mechanism 74, and selecting the light other than the first wavelength band as imaging light and emitting it to the camera mechanism 74. In this embodiment, this function is achieved by a filter 82. Specifically, the imaging wavelength selection mechanism 76 provides a filter 82 between the light wavelength conversion plate 10 and the camera mechanism 74 (camera 80). This filter 82 has the function of blocking light in the first wavelength band and allowing light other than the first wavelength band to pass through (i.e., in this embodiment, blocking blue light in the wavelength band between 400 nm and 500 nm, and allowing light in other wavelength bands, i.e., red and green light, to pass through). Thus, the camera 80 captures an image with only blue light removed, i.e., an image formed by red and green light. In addition to the method of using filter 82 as described above, the imaging wavelength selection mechanism 76 can also select the imaging wavelength using various well-known methods such as using multiple light-receiving elements with selectable wavelengths as the detection unit of camera 80, and using a beam splitter to separate the wavelengths.

[0074] like Figure 5 As shown, in the case where foreign matter is mixed into the optical wavelength conversion sheet 10, the image P1 captured by the camera 80 shows that the foreign matter area is darker (lower brightness) than the surrounding area without foreign matter. This is believed to be caused by the fact that the light transmittance of all wavelength regions of blue, red, and green in the foreign matter area is lower than that of other areas.

[0075] And, as Figure 6 As shown, in the case where there is a large amount of quantum dots in the optical wavelength conversion plate 10, the portion with a large amount of quantum dots appears brighter (higher brightness) than other portions in the image P2 captured by the camera 80. This is believed to be caused by the fact that in the portion with a large amount of quantum dots, the transmittance of blue light decreases while the amount of red and green light increases. Therefore, the imaging wavelength selection mechanism 76 cuts off blue light, and the increased amount of red / green light is detected.

[0076] In addition, such as Figure 7 As shown, in the case where the optical wavelength conversion plate 10 has a small amount of quantum dots, the image P3 captured by the camera 80 shows that the area with a small amount of quantum dots is darker (lower brightness) than other areas. This is believed to be caused by the fact that in the area with a small amount of quantum dots, the transmittance of blue light is increased, but the amount of red and green light decreases. Therefore, the imaging wavelength selection mechanism 76 cuts off blue light, and the decrease in the amount of red / green light is detected.

[0077] in addition, Figure 5 , Figure 6 , Figure 7 The spectrum of wavelengths at the defective area is shown. This spectrum uses blue light (wavelength band from 400 nm to 500 nm) as the illumination source. No wavelength cutoff filter is used on the camera side, and the wavelength spectrum of the defective area is measured using a camera with wavelength measurement capabilities. With the normal portion (excluding the defective area) set as "standard" (double-dotted lines in the graph), the difference between the normal portion and the defective portion at each wavelength is calculated to obtain the spectrum of light intensity at the defective area. Similar to the brightness pattern described in the photograph, the content of the defective area can be understood through a pattern of the brightness levels of the blue and red / green portions of the spectrum within the defective area.

[0078] During inspection using the inspection device 70, areas deemed to be defective, as described above, are detected based on images captured by the camera 80. Specifically, areas where the brightness of the captured image differs from that of the surrounding areas by 7% or more, and whose size is 100 μm or more, are detected as defective areas. Furthermore, defect detection can be performed visually or mechanically using a known image analysis device. According to the inspection method of the present invention, defective areas can be reliably detected even when there is a brightness difference between the quantum dot portion and the partition portion. Specifically, in a surface inspection image where the brightness of the partition portion is 135, and the brightness of the quantum dots excluding the partition portion is 145, with an overall average of 140, relatively stable detection is possible as long as the approximate brightness difference is 10 or more.

[0079] Furthermore, in this embodiment, the brightness of the image is not checked by distinguishing wavelength bands. However, the brightness of the image can also be checked by distinguishing wavelength bands by analyzing the spectrum of the captured image, such as by observing that there is more red light and less green light. This allows for the detection of the quantity (or quantity) of quantum dots emitting red (or green) light.

[0080] As described above, in the inspection device 70, there is no need to inspect (photograph) according to the type of quantum dot; the defect can be detected by just one inspection (photograph), making inspection easy.

[0081] Furthermore, in the inspection device 70, by using the filter 82 to cut off the light (blue light) in the first wavelength band, the influence of defects (noise) that would not be a problem when the light wavelength conversion sheet 10 is installed in the liquid crystal display device can be eliminated, thus enabling high-precision inspection.

[0082] That is, unlike red and green light, the blue light directed towards the camera 80 also transmits through the back side (lower layer) of the quantum dot layer 20. Therefore, it is affected by defects (noise) such as scratches on the laminated film 24, which would not be a problem when installed in a liquid crystal display device. Furthermore, while microscopic air bubbles generated between the quantum dot layer 20 or its layers would not be a problem when installed in a liquid crystal display device, the blue light is still affected by these defects (noise). In the inspection device 70, by blocking this blue light, the influence of noise can be eliminated, enabling high-precision inspection.

[0083] return Figure 3 If no defects are detected during inspection using the inspection device 70, the inspected wavelength conversion sheet 10 is wound onto the take-up roller 90 as a product. Conversely, if defects are detected, the defective portion is removed before winding onto the take-up roller 90. For example, defects can be removed by cutting a certain length of the wavelength conversion sheet 10 containing the defective portion. Thus, in the wavelength conversion sheet 10 used as a product, every 1m 2 The number of defective parts is set to less than 1.

[0084] [Second Implementation]

[0085] like Figure 8 As shown, in the manufacturing equipment 100 (optical wavelength conversion sheet manufacturing apparatus) of the second embodiment, in addition to the forming apparatus 52 (forming process), inspection apparatus 70 (primary inspection apparatus, primary inspection process), and take-up roller 90 described above, an inspection apparatus 110 (secondary inspection apparatus, secondary inspection process) is also provided. Furthermore, when utilizing... Figure 8 In the following description of the drawings, the same reference numerals will be used for components that are the same as those in the embodiments described above, and their descriptions will be omitted. Furthermore, in the following description, the inspection device 70 will be referred to as the primary inspection device 70, and the inspection device 110 will be referred to as the secondary inspection device 110.

[0086] like Figure 9 As shown, the secondary inspection device 110 includes a secondary illumination mechanism 112 (secondary illumination process) and a secondary camera mechanism 114 (secondary imaging process). The secondary illumination mechanism 112 includes a light source 116 that emits white light including blue light, red light, and green light. The light source 116 is disposed on the back side of the wavelength conversion plate 10 and illuminates the back side of the wavelength conversion plate 10 with illumination light (white light). In this embodiment, the illumination light is irradiated with the back side of the wavelength conversion plate 10 at an angle of 45° to the vertical direction.

[0087] The secondary camera mechanism 114 includes a camera 118. The camera 118 is positioned on the surface side of the wavelength conversion plate 10, with its photographic optical axis aligned with the illumination optical axis from the light source 116, and captures images of the wavelength conversion plate 10. As described above, in this embodiment, the structure is configured to illuminate the wavelength conversion plate 10 at a 45° angle to the vertical direction; therefore, the camera 118 captures images of the wavelength conversion plate 10 from a 45° angle to the vertical direction. Furthermore, the inspection device 70 described above (see reference...) Figure 4 Similarly, it can be configured to illuminate the light source vertically toward the light wavelength conversion plate 10 and to take pictures of the light wavelength conversion plate 10 from a vertical direction.

[0088] like Figure 10 As shown, when foreign matter is mixed into the optical wavelength conversion sheet 10, the image P10 (secondary image) captured by the camera 118 and the image P1 (primary image) captured by the camera 80 described above (see reference) Figure 5 Similarly, the portion containing the foreign object is darker (lower in brightness) than the other portions. This is believed to be caused by the fact that the light transmittance of the foreign object portion is lower than that of the other portions.

[0089] On the other hand, such as Figure 11 As shown, in the case where the optical wavelength conversion sheet 10 contains a large amount of quantum dots, the image P20 (secondary image) captured by the camera 118 and the image P2 (primary image) captured by the camera 80 (see reference) Figure 6 Conversely, the areas with a higher concentration of quantum dots appear darker (lower in brightness) than other areas. This is believed to be caused by the fact that even in the areas with a higher concentration of quantum dots, the reduced transmittance of blue light and the increased amount of red and green light cannot compensate for the decrease in blue light, resulting in an overall decrease in light intensity (the sum of blue, red, and green light).

[0090] On the other hand, such as Figure 12 As shown, in the case where the amount of quantum dots in the optical wavelength conversion sheet 10 is small, the image P30 (secondary image) captured by the camera 118 is also similar to the image P3 (primary image) captured by the camera 80 described above (see reference). Figure 7 Conversely, the regions with lower quantum dot concentrations are brighter (higher brightness) than the other regions. This is believed to be due to the fact that in the regions with lower quantum dot concentrations, there is less red and green light produced by the quantum dots, but the increased transmittance of the white illumination light results in an increased amount of light.

[0091] Furthermore, the secondary inspection device 110 differs from the primary inspection device 70 in that it uses white light for illumination and lacks a filter 82 that cuts off light (blue light) in the first wavelength band (see reference). Figure 4 Therefore, when defects such as scratches or foreign objects exist on the back side of the laminated film 24, which is further back than the quantum dot layer 20, the defective areas appear darker (lower brightness) in the photographic image (secondary photographic image) captured by the camera 118. On the other hand, when fine bubbles are present in the quantum dot layer 20 or between the layers, the defective areas appear brighter (higher brightness) in the photographic image (secondary photographic image) captured by the camera 118.

[0092] Thus, the secondary camera image becomes an image in a different manner than the primary camera image. When comparing the two, the primary camera image is inspected using the same lighting as the installation method, so defects are reproduced in the same way as in the installation method. In contrast, the secondary camera image may reproduce defects in a different way than in the installation method. Therefore, when either is used for inspection, the primary camera image is preferred.

[0093] On the other hand, as described above, in this embodiment, which obtains images of different types of defects using either a primary image or a secondary image, the type of defect can be determined by comparing the two (through a comparison process and a comparison device). Specifically, for example, in a primary image, it is difficult to determine whether a defect that appears darker (lower brightness) is caused by foreign matter or a defect due to a low amount of quantum dots using only the primary image. In contrast, in a secondary image, when the foreign matter is dark (lower brightness) and the amount of quantum dots is low, the defect appears brighter (higher brightness). Therefore, by comparing the primary and secondary images, the type of defect can be determined. Furthermore, the comparison between the primary and secondary images can be performed visually or mechanically using a known image analysis device.

[0094] Furthermore, in this embodiment, an example of using different light sources and cameras in the primary inspection device and the secondary inspection device has been described. However, a common light source and camera can also be used in both the primary and secondary inspection devices. In this case, a light source capable of selectively illuminating blue light and white light is used. A primary image is obtained by illuminating blue light and taking a picture with the filter 82 inserted into the photographic optical axis, and a secondary image is obtained by illuminating white light and taking a picture with the filter 82 retracted from the photographic optical axis.

[0095] [Verification Result]

[0096] The following uses Figure 13The optical wavelength conversion sheets with different layer structures are inspected by a primary inspection device 70 and a secondary inspection device 110, and the results of the verification based on the inspection of each inspection device are explained.

[0097] like Figure 13 As shown, in the verification, the optical wavelength conversion sheet uses a two-layer structure consisting of an optical layer 14 and a quantum dot layer 20, a three-layer structure in addition to the two layers mentioned above, a four-layer structure in addition to the three layers mentioned above, a laminated film 24 on the back side, and a five-layer structure in addition to the four layers mentioned above, a laminated film 22 on the surface side.

[0098] Furthermore, the four types of optical wavelength conversion sheets 10 were inspected by the primary inspection device 70 and the secondary inspection device 110, and their detectability, brightness of defects, and noise were evaluated. In the evaluation of detectability, for defects that cause problems when installed in the backlight unit of a liquid crystal display device (hereinafter referred to as actual damage defects), the evaluation was "A" if the content causing the problem could be identified and detected, "B" if the actual damage defect could be detected, and "C" if the actual damage defect could not be detected.

[0099] Furthermore, in the evaluation of the brightness of defects, when the brightness of the defect is reproduced in the same way as the backlight unit installed in the liquid crystal display device, it is evaluated as "A"; when the brightness of the defect is reproduced in a way different from the backlight unit installed in the liquid crystal display device, it is evaluated as "B"; and when the brightness of the defect cannot be detected, it is evaluated as "C".

[0100] In addition, in the evaluation of noise, the following conditions are rated as follows: "A" when there is almost no detected noise and the actual damage defect can be identified; "B" when there is little detected noise and the actual damage defect can be identified by constant distinction of shape and / or size; "C" when there is detected noise and the actual damage defect is difficult to identify by mechanical detection methods, but can be identified by visual detection methods; and "D" when there is a lot of detected noise and the actual damage defect cannot be identified.

[0101] The verification results are as follows Figure 13 As shown. Figure 13 As shown, when comparing the primary inspection device 70 and the secondary inspection device 110, it can be confirmed that the evaluation of the primary inspection device 70 is higher than that of the secondary inspection device 110, and it can perform inspections with high accuracy.

[0102] {Other Implementation Methods}

[0103] Manufacturing apparatus 50 (an apparatus for manufacturing optical wavelength conversion sheets) as described in the above embodiments (see reference) Figure 3 )Set up removal by inspection device 70 (inspection process) (reference) Figure 4 A removal device (removal process) for the detected defective areas. Similarly, this can be done in manufacturing equipment 100 (reference). Figure 8 )Set to remove by inspection devices 70, 110 (reference) Figure 9 )A device for removing defects detected in the area (removal process).

[0104] Furthermore, in the above embodiment, an example of detecting defects was given where the brightness of the captured image differs from that of the surrounding area by more than 7%. However, in addition to this condition, defects can also be detected in areas with a size of 100 μm or more and 5000 μm or less. Here, the size of the area with a brightness difference from the surrounding area refers to the square root of the area of ​​the defect.

[0105] [Defect detection through image analysis]

[0106] Furthermore, when detecting defects mechanically using image analysis devices, i.e., when detecting defects by analyzing video images captured by camera 80 or camera 118, image processing of the analyzed object can be performed to improve detection accuracy. Examples of image processing include image correction for contrast, brightness, and color; noise removal; edge enhancement and dilation / contraction processing; image conversion to monochrome; and image feature extraction.

[0107] As an example, regarding defects caused by large fibrous foreign objects, the defects are easy to identify visually due to their long length. However, the defects are narrow and the difference in brightness between the displayed area and the normal area is small. Furthermore, due to differences between the particle point and the partition area, even normal areas may have brightness variations. In such cases, fibrous defects are detected as ruptures and identified as small defects. However, by adding expansion / contraction processing to the detection image, the defect size can be detected at a size close to the original size.

[0108] As mentioned above, a specific example of detecting defects through image analysis is provided, utilizing... Figure 14 , Figure 15 Please provide an explanation. Figure 14The image shows a wavelength conversion plate, where the brightness of the central portion differs from that of the surrounding portion (in this example, it is low brightness) due to the aforementioned fibrous foreign matter. The upper part shows a photographic image of the inspection device based on the wavelength conversion plate, and the lower part shows an image of the central portion of the upper image magnified by a microscope. It can be seen that fibrous defects exist in the microscope image, but in the photographic image, the brightness difference in the fibrous defect portion relative to the surrounding particle points or septa appears to be very small.

[0109] Figure 15 express Figure 14 The analysis results of the camera images shown are as follows. Additionally, Figure 15 exist Figure 15 The left, center, and right sides respectively show three analysis results obtained by changing the image processing content or threshold of the image of the object being analyzed.

[0110] and, Figure 15 In the image above, areas determined to have different brightness from their surroundings are colored. In this example, areas judged to have lower brightness than their surroundings are colored. The second section shows the size of the defect areas determined to have different brightness from their surroundings; in this example, it shows the number of pixels judged to have lower brightness than their surroundings. The third section shows the threshold value used to determine the difference in brightness; in this example, pixels below this threshold are judged to have lower brightness than their surroundings. The fourth section shows the types of image processing performed on the image being analyzed. In this example, examples of standard image processing (image correction, noise removal, etc.) are shown on the left and center, and an example of dilation / shrinkage processing is shown on the right in addition to standard image processing. By applying dilation / shrinkage processing to the image, defect determination can be performed with dimensions close to those corresponding to actual fibrous defects.

[0111] [Three checks]

[0112] In the above embodiment, defective areas were detected by a single inspection based on inspection device 70 or a second inspection based on inspection device 110. However, by visually observing the results of the single or second inspection, it was determined that the defective areas detected also included areas that would not have quality problems when used in a product (such as a backlight device for a liquid crystal panel). Therefore, the defective areas detected by the single or second inspection can be reduced by further inspection (hereinafter referred to as a third inspection).

[0113] In the three inspections, defective areas detected by the first or second inspection are designated as candidate defective areas (defective area candidate inspection process), and from these candidates, areas are determined as the final defective areas to be inspected (defective area determination process). Areas determined by the three inspections as candidate defective areas, whose brightness differs from the surrounding areas based on visual observation, are determined as the final defective areas in the three inspections. Furthermore, the areas determined as the final defective areas by the inspection process, which includes the defective area candidate inspection process and the defective area determination process, are removed in the aforementioned removal process, and the optical wavelength conversion sheet 10 is manufactured. Therefore, by removing only the final defective areas confirmed by visual inspection, a sheet with a high production yield and good quality can be obtained during manufacturing.

[0114] As mentioned above, in the three-stage inspection, among the candidate defect locations detected by the first or second inspection, the locations whose brightness differs from the surrounding areas are determined by visual observation to be the final defect locations. Therefore, the three-stage inspection can be performed by actually visually observing the candidate defect locations. In addition, visual observation can be performed by directly looking at the wavelength conversion sheet, or by visually observing the video image taken of the wavelength conversion sheet.

[0115] Furthermore, during visual observation, it was found that if the brightness difference with the surrounding areas meets a constant "benchmark" and / or the defect size (the size of the area whose brightness differs from the surrounding areas) meets a constant "benchmark," then the area whose brightness differs from the surrounding areas is determined. Therefore, if the aforementioned "benchmark" is identified, the final defect location can be determined without actual visual observation. That is, the area whose brightness difference with the surrounding areas and / or defect size meets the aforementioned "benchmark" can be considered as the area determined as the final defect location by visual observation. Thus, in three inspections, the video images taken of the optical wavelength conversion sheet can be analyzed, and from the candidate defect locations, the area whose brightness difference with the surrounding areas and / or defect size meets the aforementioned "benchmark" can be determined as the final defect location.

[0116] Furthermore, in this embodiment, in order to determine the final defect location by analyzing the photographic image taken of the optical wavelength conversion sheet as described above, the aforementioned "reference" is calculated as follows.

[0117] First, the defective areas detected by the first or second inspection are determined by visual observation. The determination is performed in the same manner as when the wavelength conversion sheet 10 is used as a product. That is, the wavelength conversion sheet 10 is used as a backlight device for a liquid crystal panel. Specifically, a blue LED backlight, a wavelength conversion sheet whose defective areas (candidate defective areas) are detected by the first or second inspection, and a 3M (registered trademark) prism sheet integrated into a DBEF (registered trademark) as a light diffuser are arranged in sequence. The wavelength conversion sheet 10 is illuminated from the back side with blue light, and the candidate defective areas are visually observed from the surface side.

[0118] Regarding specific examples of situations involving visual observation as described above, using... Figure 16 , Figure 17 Please provide an explanation. Additionally, in Figure 16 , Figure 17 In the example, in addition to the two layers consisting of optical layer 14 and quantum dot layer 20, a support layer 12 is also provided as a three-layer structure optical wavelength conversion sheet (see reference). Figure 13 The process was performed. The quantum dot layer of the optical wavelength conversion sheet has a thickness of 30 μm, the partitions are 100 μm thick, and the quantum dot housing size is 350 μm. During inspection, the brightness of the particle dot layer was 145, the brightness of the partition layer was 135, and the average brightness of the observation surface was 140. Furthermore, the brightness values ​​shown here are the grayscale values ​​of corresponding parts when the image in the photographed image is displayed at 255 grayscale on a grayscale scale.

[0119] Furthermore, the size of the defect region (candidate defect region) is set as the number of pixels detected from the image of the object under inspection (candidate defect region), and the area of ​​the defect region (candidate defect region) is calculated from this number of pixels, which is taken as the square root of the calculated area. The brightness of the defect region is determined by the brightness ratio of the defect region (candidate defect region) to the average brightness.

[0120] Figure 16 , Figure 17 This involves defining a two-dimensional area with the size of the defect on the horizontal axis and its brightness on the vertical axis. Defects detected through one or two inspections are used as candidate indicators for assigning defects. The type of indicator reflects the result of visual observation: an indicator "0" indicates a candidate defect for which no brightness difference with surrounding areas can be visually confirmed, and therefore it is not considered a defect during visual inspection; an indicator "×" indicates a candidate defect for which a brightness difference with surrounding areas can be visually confirmed, and therefore it is determined to be a final defect based on visual observation. Figure 16 This shows the results of visual observation when a defective area (a candidate defective area) detected through one or two inspections is found to be brighter than the surrounding area. Figure 17 This shows the results of visual observation when a defective area (a candidate defective area) detected by a single or double inspection is found to be less bright than the surrounding area.

[0121] like Figure 16 As shown, during visual inspection, among the defective areas (candidates) that were brighter than their surroundings after one or two inspections, those with an average brightness of 135% or higher were determined to be the final defective areas. Defective areas with an average brightness less than 135%, especially less than 130%, were not detected and were not considered final defects. The reason for this is believed to be that, in an environment with light emission, the presence of defects with significantly higher brightness than their surroundings makes them difficult for humans to identify, thus falling within the acceptable brightness range for the product. Therefore, from... Figure 16 The example shows that 135% of the average brightness is set as the "benchmark", and the parts above the "benchmark" are considered as the final defect parts under visual observation.

[0122] And, as Figure 16 As shown, during visual observation, among the candidate defects (defect areas) detected as brighter than their surroundings through one or two inspections, those with a size greater than 400 μm were identified as final defects. Among the candidate defects (defect areas) with a size smaller than 400 μm, none were identified as final defects. This is believed to be because areas with higher brightness than their surroundings, exceeding the size of the particle dot layer's storage chamber (350 μm), are easier to visually identify. Thus, from... Figure 16 The example also shows that a size of 400μm is set as the "reference", and the parts above the "reference" are considered as the final defect parts under visual observation.

[0123] In addition, such as Figure 17 As shown, during visual inspection, defects with an average brightness below 90% of their surroundings (candidate defects) were identified as final defects after one or two inspections. This is believed to be due to the fact that, under a bright light source, dark defects are more easily visually identified. Thus, from... Figure 17 The example shows that 90% of the average brightness is set as the "benchmark", and the parts below the "benchmark" are considered as the final defect parts under visual observation.

[0124] As mentioned above, from Figure 16 , Figure 17The example yielded three "benchmarks". Furthermore, in this embodiment, three inspections were performed using the "benchmarks" calculated as described above. Specifically, the light wavelength conversion sheet was illuminated from the back side under the same conditions as visual inspection, and the video images taken from the surface side were analyzed. The areas that met the "benchmarks", such as areas with an average brightness of 135% or more, were identified as the final defect areas.

[0125] Furthermore, the "reference standard" used in the three inspections is not limited to this; therefore, for example, a region with a size of 400 μm or a region with an average brightness of 90% or less can be identified as the final defect region. Of course, other "reference standards" besides those mentioned above can also be used for the three inspections. Moreover, the "reference standard" used in the three inspections is not limited to one type; therefore, for example, a region with an average brightness of 135% or more and a size of 400 μm or more can be identified as the final defect region, and multiple "reference standards" can be used for the three inspections. In addition, when using multiple "reference standards," a region that satisfies all of the multiple "reference standards" can be identified as the final defect region, or a region that satisfies one (or more) of the multiple "reference standards" that are pre-set can be identified as the final defect region.

[0126] By performing the three checks described above, the brightness or size of defective areas can be determined according to their actual usage conditions. Furthermore, with only one or two checks, there is a risk that even areas that are not problematic in actual use may be detected as defective areas, thus excluding them from the product and causing a decrease in yield. However, by performing three checks, this problem can be prevented, and optical wavelength conversion sheets can be manufactured with a high yield.

[0127] Furthermore, by performing three inspections, a high-quality optical wavelength conversion sheet can be obtained that excludes defective areas considered to be problematic in the product, specifically areas with an average brightness of 135% or more and / or areas with a size of 400 μm or more and / or areas with an average brightness of 90% or less. In other words, the optical wavelength conversion sheet of the present invention manufactured through three inspections does not include the aforementioned defective areas and is composed only of areas other than the aforementioned defective areas (normal areas), thus achieving a high quality.

[0128] As described above, the high-quality wavelength conversion sheet of the present invention is used in backlight devices for liquid crystal panels, liquid crystal panels, and liquid crystal display devices. Furthermore, the backlight devices, liquid crystal panels, and liquid crystal display devices of these liquid crystal panels are of the same high quality as the wavelength conversion sheet of the present invention.

[0129] Symbol Explanation

[0130] 10-wavelength conversion sheet, 12-support layer, 12a-support sheet, 14-optical layer, 14a-optical sheet, 20-quantum dot layer (wavelength conversion layer), 20a-cast film, 22-laminated film (surface-side protective film), 24-laminated film (back-side protective film), 30-partition, 32-receiving chamber, 34-light emitter (wavelength converter), 50-manufacturing equipment (manufacturing apparatus for wavelength conversion sheet), 52-forming apparatus (forming process), 54-first feed roller, 54a, 54b-conveyor rollers, 56-first casting die, 58-shaping roller, 58a-ultraviolet light source, 58b, 58c-conveyor rollers, 60-second casting die, 62-second feed roller, 62a-conveyor roller, 64-layering roller. 64a-Ultraviolet light source, 64b-Conveyor roller, 70-Inspection device (inspection process, primary inspection device, primary inspection process), 72-Irradiation mechanism (irradiation process), 74-Camera mechanism (camera process), 76-Camera wavelength selection mechanism (camera wavelength selection process), 78-Light source, 80-Camera, 82-Filter, 90-Take-up roller, 100-Manufacturing equipment (manufacturing device for optical wavelength conversion sheet), 110-Inspection device (secondary inspection device, secondary inspection process), 112-Secondary irradiation mechanism, 114-Secondary camera mechanism, 116-Light source, 118-Camera, P1, P2, P3-Camera images (primary camera images), P10, P20, P30-Camera images (secondary camera images).

Claims

1. A method for inspecting an optical wavelength conversion sheet, comprising an optical wavelength conversion layer having an optical wavelength conversion layer including an optical wavelength converter that emits light of a second wavelength band with a peak wavelength different from that of the first wavelength band light by receiving light of a first wavelength band, wherein the inspection method includes: The first inspection process, the second inspection process, and the comparison process. The single inspection process includes: In one irradiation process, illumination light containing the first wavelength band is directed toward the back of the optical wavelength conversion sheet; In one imaging process, the light wavelength conversion sheet is photographed from its surface side; and In the imaging wavelength selection process, between the primary illumination process and the primary imaging process, the light from the optical wavelength conversion sheet is separated into light in the first wavelength band and light other than the first wavelength band, and the light other than the first wavelength band is selected as the imaging light and emitted into the primary imaging process. The secondary inspection process includes: In the secondary irradiation process, illumination light containing light from the first wavelength band and the second wavelength band is directed toward the back of the optical wavelength conversion sheet; and The secondary imaging process involves photographing the optical wavelength conversion sheet from its surface side. In the comparison process, the brightness of the primary camera image taken in the first inspection process is compared with the brightness of the secondary camera image taken in the second inspection process. The type of defect is determined by comparing the brightness of the primary camera image with that of the secondary camera image.

2. The inspection method for the optical wavelength conversion sheet according to claim 1, wherein, On the optical wavelength conversion layer, multiple storage compartments are formed by using partitions perpendicular to the layer. The optical wavelength converter is sealed inside each of the storage chambers.

3. The inspection method for the optical wavelength conversion sheet according to claim 1, wherein, The optical wavelength conversion sheet has a support layer on the back side of the optical wavelength conversion layer.

4. The inspection method for the optical wavelength conversion sheet according to claim 2, wherein, The optical wavelength conversion sheet has a support layer on the back side of the optical wavelength conversion layer.

5. The method for inspecting the optical wavelength conversion sheet according to claim 3, wherein, The back side of the support layer is protected by a back protective film.

6. The method for inspecting the optical wavelength conversion sheet according to claim 4, wherein, The back side of the support layer is protected by a back protective film.

7. The method for inspecting the optical wavelength conversion sheet according to any one of claims 1 to 6, wherein, The optical wavelength conversion sheet has a transparent optical layer on the surface side of the optical wavelength conversion layer.

8. The method for inspecting the optical wavelength conversion sheet according to claim 7, wherein, The surface of the optical layer is protected by a surface protective film.

9. The method for inspecting the optical wavelength conversion sheet according to any one of claims 1 to 6, wherein, The first wavelength band is included in the wavelength band of visible light.

10. An inspection apparatus for an optical wavelength conversion sheet, comprising an optical wavelength conversion layer including an optical wavelength converter that receives light in a first wavelength band and emits light in a second wavelength band with a peak wavelength different from that in the first wavelength band, the inspection apparatus comprising: A primary inspection device, a secondary inspection device, and a comparison device. The single-inspection device has: The primary irradiation mechanism irradiates the back of the light containing the first wavelength band toward the back of the light wavelength conversion plate; A single camera mechanism is used to photograph the optical wavelength conversion sheet from the surface side of the sheet; and The imaging wavelength selection mechanism separates light into light in the first wavelength band and light other than the first wavelength band between the optical wavelength conversion plate and the primary imaging mechanism, and selects the light other than the first wavelength band as imaging light and emits it toward the primary imaging mechanism. The secondary inspection device has the following features: The secondary illumination mechanism illuminates the back of the optical wavelength conversion plate with light including the light of the first wavelength band and the light of the second wavelength band; and A secondary camera mechanism captures an image of the optical wavelength conversion sheet from its surface side. The comparison device compares the brightness of a primary camera image captured by the primary inspection device with the brightness of a secondary camera image captured by the secondary inspection device, and determines the type of defect based on the comparison result between the brightness of the primary camera image and the brightness of the secondary camera image.

11. A method for manufacturing an optical wavelength conversion sheet, comprising a method for manufacturing an optical wavelength conversion sheet having an optical wavelength conversion layer, the optical wavelength conversion layer comprising an optical wavelength converter that emits light of a second wavelength band with a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band, the manufacturing method comprising: The forming process forms the optical wavelength conversion layer; and The inspection process involves inspecting the optical wavelength conversion sheet on which the aforementioned optical wavelength conversion layer is formed. The inspection process includes a primary inspection process, a secondary inspection process, and a comparison process. The single inspection process includes: In one irradiation process, illumination light containing the first wavelength band is directed toward the back of the optical wavelength conversion sheet; In one imaging process, the light wavelength conversion sheet is photographed from its surface side; and In the imaging wavelength selection process, between the primary illumination process and the primary imaging process, the light from the optical wavelength conversion sheet is separated into light in the first wavelength band and light other than the first wavelength band, and the light other than the first wavelength band is selected as the imaging light and emitted into the primary imaging process. The secondary inspection process includes: In the secondary irradiation process, illumination light containing light from the first wavelength band and the second wavelength band is directed toward the back of the optical wavelength conversion sheet; and The secondary imaging process involves photographing the optical wavelength conversion sheet from its surface side. In the comparison process, the brightness of the primary camera image taken in the first inspection process is compared with the brightness of the secondary camera image taken in the second inspection process. The type of defect is determined by comparing the brightness of the primary camera image with that of the secondary camera image.

12. An apparatus for manufacturing an optical wavelength conversion sheet, comprising an optical wavelength conversion layer including an optical wavelength converter that emits light of a second wavelength band with a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band, the manufacturing apparatus comprising: Forming apparatus, forming the optical wavelength conversion layer; and The inspection device inspects the optical wavelength conversion sheet on which the optical wavelength conversion layer is formed. The inspection device includes a primary inspection device, a secondary inspection device, and a comparison device. The single-inspection device has: The primary irradiation mechanism irradiates the back of the light containing the first wavelength band toward the back of the light wavelength conversion plate; A single camera mechanism is used to photograph the optical wavelength conversion sheet from the surface side of the sheet; and The imaging wavelength selection mechanism separates light into light in the first wavelength band and light other than the first wavelength band between the optical wavelength conversion plate and the primary imaging mechanism, and selects the light other than the first wavelength band as imaging light and emits it toward the primary imaging mechanism. The secondary inspection device has the following features: The secondary illumination mechanism illuminates the back of the optical wavelength conversion plate with light including the light of the first wavelength band and the light of the second wavelength band; and A secondary camera mechanism captures an image of the optical wavelength conversion sheet from its surface side. The comparison device compares the brightness of a primary camera image captured by the primary inspection device with the brightness of a secondary camera image captured by the secondary inspection device, and determines the type of defect based on the comparison result between the brightness of the primary camera image and the brightness of the secondary camera image.

13. A method for manufacturing an optical wavelength conversion sheet, comprising a method for manufacturing an optical wavelength conversion sheet having an optical wavelength conversion layer, the optical wavelength conversion layer comprising an optical wavelength converter that emits light of a second wavelength band with a peak wavelength different from that of the light of the first wavelength band by receiving light of the first wavelength band, the manufacturing method comprising: The forming process forms the optical wavelength conversion layer; The inspection process involves inspecting the optical wavelength conversion sheet on which the optical wavelength conversion layer is formed. and The removal process involves removing the defective parts detected in the inspection process from the parts that will be used in the product. The inspection process includes a primary inspection process, a secondary inspection process, and a comparison process. The single inspection process includes: In one irradiation process, illumination light containing the first wavelength band is directed toward the back of the optical wavelength conversion sheet; A single imaging process involves photographing the optical wavelength conversion sheet from its surface side. In the imaging wavelength selection process, between the first illumination process and the first imaging process, the light from the optical wavelength conversion sheet is separated into light in the first wavelength band and light other than the first wavelength band, and the light other than the first wavelength band is selected as imaging light and emitted into the first imaging process; The defect candidate detection process uses the video images obtained in the first imaging process to detect candidate defect locations; and The defect location determination process involves selecting the location from the candidate defect locations to be inspected. The secondary inspection process includes: In the secondary irradiation process, illumination light containing light from the first wavelength band and the second wavelength band is directed toward the back of the optical wavelength conversion sheet; and The secondary imaging process involves photographing the optical wavelength conversion sheet from its surface side. In the defect location determination process, when illumination light containing the first wavelength band is shone from the back side of the optical wavelength conversion sheet and observed from the surface side, the location whose brightness differs from the surrounding area by visual observation is determined to be the defect location. In the comparison process, the brightness of the primary camera image taken in the first inspection process is compared with the brightness of the secondary camera image taken in the second inspection process. The type of defect is determined by comparing the brightness of the primary camera image with that of the secondary camera image.

14. The method for manufacturing the optical wavelength conversion plate according to claim 13, wherein, In the defect location determination process, a location whose brightness is 135% or more greater than that of the surrounding location is considered as a location whose brightness is different from that of the surrounding location by visual observation, and is thus identified as the defect location.

15. An optical wavelength conversion sheet manufactured by the manufacturing method of the optical wavelength conversion sheet according to claim 13.

16. An optical wavelength conversion sheet manufactured by the manufacturing method of the optical wavelength conversion sheet according to claim 14.

17. The optical wavelength conversion sheet according to claim 15 or 16, wherein, A support layer is provided on the back side of the optical wavelength conversion layer.

18. The optical wavelength conversion sheet according to claim 15 or 16, wherein, Multiple storage compartments are formed on the optical wavelength conversion layer by using partitions perpendicular to the layer.

19. A backlight device for a liquid crystal panel, comprising the optical wavelength conversion sheet as described in claim 15 or 16.

20. A liquid crystal panel comprising the optical wavelength conversion sheet as described in claim 15 or 16.

21. A liquid crystal display device comprising the wavelength conversion sheet, liquid crystal panel, and backlight device as described in claim 15 or 16.

Images