JP6956004B2 - Defect inspection equipment and manufacturing method of defect inspection equipment - Google Patents

Description

The present invention relates to a defect inspection device and a method for manufacturing the defect inspection device.

Conventionally, there has been known a defect inspection device that inspects the presence or absence of defects in the inspection target based on an image of the inspection target captured by a camera. Such a defect inspection device generally has a lighting unit that illuminates the inspection target. For example, the defect inspection device described in Patent Document 1 passes a light source (light source 11) and the first light emitted from the light source that travels in the central axis direction, and is different from the central axis direction. A louver (honeycomb structure 17a) having a plurality of through holes that restrict the passage of the second light traveling in a direction and formed in a curved shape for concentrating the first light on the camera is provided. It has an illumination unit (light source 10).

Japanese Patent No. 6039119

Since the lighting unit of the defect inspection device disclosed in Patent Document 1 can collect the first light on the camera, the inspection target can be suitably illuminated. However, it is not easy to actually manufacture the lighting unit. For example, the louver has a plurality of through holes having different central axis directions because it is curved, but the louver having such a plurality of through holes has a complicated shape and cannot be easily manufactured. Further, the calculation of the value of the curvature curvature of the louver is complicated, and it is not easy to manufacture the louver with the calculated curvature. Further, in order to appropriately inject the illumination light into each of the plurality of through holes of the louver, it is necessary to form the light source so that the central axis of each through hole and the optical axis of the light incident in each through hole are aligned with each other. However, it is not easy to form such a light source.

The present invention provides a defect inspection apparatus having an illuminating unit capable of appropriately illuminating an inspection object and easily manufacturing the inspection object, and a method for manufacturing a defect inspection apparatus having an illuminating unit capable of appropriately illuminating the inspection object and easily manufacturing the inspection object. The purpose is to do.

In order to achieve the above object, the defect inspection apparatus according to the first aspect of the present invention is
A lighting unit (for example, a lighting device 110) that illuminates an inspection target (inspection target T),
A camera (for example, a line sensor camera 120) that captures the inspection target illuminated by the lighting unit, and
An inspection unit (for example, a computer 130) that inspects the presence or absence of defects in the inspection target based on the captured image of the inspection target captured by the camera is provided.
The lighting unit
A light source (for example, a light source 111) that emits light for illuminating the inspection target,
A plurality of through holes (for example, through holes 112A) in which the central axis (for example, the central axis 112B) is parallel, and of the light emitted from the light source, passes through the first light traveling in the central axis direction. A louver (for example, louver 112) having a plurality of through holes for limiting the passage of the second light traveling in a direction different from the central axis direction.
A condensing lens (for example, a Fresnel lens 113) that condenses the first light that has passed through the plurality of through holes to the camera.
Equipped with a,
The camera is a line sensor camera that captures a line-shaped area extending in the left-right direction.
The condenser lens is a Fresnel lens.
The line sensor camera captures the line-shaped region deviated from the region illuminated by the light emitted from the center of the Fresnel lens in the inspection target.

According to the above configuration, it is possible to easily manufacture an illuminating unit capable of suitably illuminating the inspection target.

According to the above configuration, a captured image suitable for inspection for the presence or absence of defects can be obtained.

The center of the line-shaped region in the left-right direction coincides with the optical axis passing through the center of the Fresnel lens in the left-right direction.
You may do so.

According to the above configuration, a captured image suitable for inspection for the presence or absence of defects can be obtained.

The Fresnel lens is placed on the upper surface of the louver.
The illumination unit includes a light-shielding member on the upper surface of the louver that closes the through hole that is not covered by the Fresnel lens and regulates the movement of the Fresnel lens in the front-rear direction.
You may do so.

According to the above configuration, it is possible to regulate the movement of the Fresnel lens in the front-rear direction while blocking unnecessary light.

The "left-right direction" may be any direction as long as the "line-shaped region" extends, and may be a top-bottom direction as well as a horizontal direction. The above-mentioned "up" and "front-back direction" may be directions with respect to the "left-right direction".

The above defect inspection device
A plurality of units including the condenser lens and the camera are provided.
It said plurality of units includes a plurality of first units arranged in a first row, and a plurality of second units arranged in the first second of parallel rows and columns,
Each of the plurality of first units and each of the plurality of second units are arranged alternately (see, for example, FIGS. 8 and 9).
You may do so.

According to the above configuration, even if the inspection target is large, it is possible to obtain a captured image suitable for inspection for the presence or absence of defects.

In order to achieve the above object, the method for manufacturing a defect inspection device according to the second aspect of the present invention is
A manufacturing method for manufacturing the above-mentioned defect inspection device.
The length of the louver in the central axis direction is set according to the inspection target (for example, modification 9).

As a result, it is possible to obtain a defect inspection device that has an illuminating unit that can illuminate the inspection target appropriately and can be easily manufactured, and can perform a suitable inspection.

According to the present invention, there is a defect inspection device having a lighting unit that can appropriately illuminate an inspection target and easily manufacture the inspection target, and a method for manufacturing a defect inspection device having a lighting unit that can appropriately illuminate the inspection target and easily manufacture the inspection target. Can be provided.

It is a block diagram which shows the structure of the defect inspection apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically the structure of the lighting apparatus and a line sensor camera of FIG. It is a schematic plan view (view from above) of the louver of FIG. FIG. 3 is a cross-sectional view taken along the line AA of FIG. It is a figure which shows the state of the light passing through the through hole of a louver. It is a figure which shows the relationship between the focused light, the imaging range of a line sensor camera, the region illuminated by the focused light in the inspection target, and the region of the region partitioned by the imaging range. It is a figure which shows typically the structure when a plurality of combinations of a Fresnel lens and a line sensor camera are provided. It is a schematic plan view when a plurality of combinations of a Fresnel lens and a line sensor camera are provided. It is a top view for demonstrating the position of each image pickup range of a plurality of line sensor cameras. It is a top view which arranged the light-shielding member together with the Fresnel lens on the upper surface of a louver.

Hereinafter, the defect inspection apparatus 100 according to the embodiment of the present invention will be described with reference to the drawings. In the following description, the same, equivalent, and corresponding ones are designated by the same reference numerals. Further, in the figure, when there are a plurality of members and the like to which the same reference numerals are to be given, only some of them are given reference numerals.

(Configuration of Defect Inspection Device 100)
As shown in FIG. 1, the defect inspection device 100 includes a lighting device 110, a line sensor camera 120, and a computer 130. The defect inspection device 100 is arranged on a synthetic resin transparent film production line and inspects the transparent film for defects. In the production line, the formed transparent film is sequentially rolled into a roll (see roll R in FIG. 1). The defect inspection device 100 inspects whether or not the inspection target T has a defect, using the transparent film before being rolled into a roll as the inspection target T. Examples of the defect include scratches and dents on the inspection target T and dust adhering to the inspection target T.

The lighting device 110 illuminates the inspection target T from below. The details of the illuminating device 110 will be described later, but the illuminating device 110 illuminates the inspection target T with an illuminating light having a long shape in the left-right direction (the direction penetrating the paper surface in FIG. 1) when viewed from above.

The line sensor camera 120 is a camera that captures a strip-shaped (line-shaped) region extending in the left-right direction. The line sensor camera 120 is arranged above the inspection target T. Although the details will be described later, the line sensor camera 120 is a portion of the inspection target T that is long in the left-right direction illuminated by the lighting device 110 from below and is in front of the center in the front-rear direction (details will be described later). ) Is imaged from above.

The computer 130 includes a display unit 131, an operation unit 132, a storage unit 133, and a control unit 134.

The display unit 131 includes a liquid crystal display, an EL (Electroluminescence) display, and the like, and displays an operation screen and the like.

The operation unit 132 includes a keyboard and the like, and receives operations from the user. The operation includes, for example, an operation of inputting various parameters required for defect inspection.

The storage unit 133 includes one or more non-volatile storage devices such as a hard disk and a flash memory. The storage unit 133 stores various programs and various data used when the control unit 134 executes processing. The storage unit 133 also has a RAM (Random Access Memory) that serves as the main memory of the processor described later in the control unit 134.

The control unit 134 includes, for example, one or more processors such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a DSP (Digital Signal Processor). The control unit 134 controls the lighting device 110 and the line sensor camera 120. The processor performs a defect inspection process (details will be described later) for inspecting a defect of the inspection target T according to a program stored in the storage unit 133. The function of the main memory such as RAM may be built in the processor.

(Lighting device 110 and line sensor camera 120)
As shown in FIG. 2, the illuminating device 110 includes a light source 111, a louver 112, and a Fresnel lens 113. The light source 111, the louver 112, and the Fresnel lens 113 are housed in a predetermined housing (not shown) so as not to leak light.

The light source 111 includes a plurality of LEDs (Light Emitting Diodes) 111A arranged in the left-right direction, a circuit board 111B for driving the LED 111A under the control of the control unit 134, and a diffuser plate arranged above the plurality of LEDs 111A. It has 111C and. The diffuser plate 111C diffuses the light L1 emitted by the LED 111A. Therefore, the light source 111 emits diffused light L2 as a whole.

As shown in FIGS. 3 to 4, the louver 112 has a honeycomb structure in which a plurality of regular hexagonal prism-shaped through holes 112A (each through hole 112A has the same shape) are arranged so as not to have a gap. The central axis 112B (the axis through which the center of the regular hexagon of the cross section passes) of each through hole 112A extends in parallel in the vertical direction, and the louver 112 as a whole has the shape of a rectangular parallelepiped elongated in the horizontal direction (each through). The holes 112A are arranged at the same position in the vertical direction). The louver 112 is formed in black. Therefore, the inner wall of each through hole 112A is black. The diffused light L2 diffused by the diffuser plate 111C is incident on each through hole 112A of the louver 112.

Here, the state of the diffused light L2 incident on each through hole 112A will be described with reference to FIG. Of the light (diffused light L2) incident on the through hole 112A, the first light L10 traveling in the direction of the central axis 112B passes through the through hole 112A. On the other hand, of the light incident on the through hole 112A, the second light L11 traveling in a direction other than the direction of the central axis 112B hits the black inner wall of the through hole 112A and is absorbed. Such a phenomenon is the same in each through hole 112A. Therefore, each through hole 112A of the louver 112 allows the first light L10 to pass through and restricts the passage of the second light L11. The first light L10 emitted from each of the through holes 112A constitutes the parallel light L3 as a whole. That is, the louver 112 extracts the parallel light L3 from the diffused light L2 emitted from the diffuser plate 111C and emits the parallel light L3. The parallel light L3 is emitted upward.

The Fresnel lens 113 cuts a circular Fresnel lens into a shape that is long in the left-right direction (for example, a rectangle, or a rectangle whose short side is arcuate) that matches the shape of the upper surface of the louver 112. It is formed by. In FIG. 2, the louver 112 and the Fresnel lens 113 are separated from each other, but in reality, the Fresnel lens 113 is placed on the upper surface of the louver 112 and fixed. The Fresnel lens 113 has a plurality of concentric circles or arcuate convex portions, the parallel light L3 from the louver 112 is refracted by the plurality of convex portions, and the parallel light L3 is focused on the line sensor camera 120. It is designed to be. This condensed light is referred to as condensed light L4. The focused light L4 emitted from the Fresnel lens 113 and focused on the line sensor camera 120 passes through the inspection target T on the way. As a result, the inspection target T is illuminated.

The line sensor camera 120 includes various image sensors (imaging elements) 121 having a plurality of photodiodes arranged in a row in the left-right direction, and an imaging lens 122 arranged below the image sensor 121 and focusing on the inspection target T. And have. Examples of the image sensor 121 include a CCD (Charged-coupled devices) image sensor and a CMOS (Complementary metal-oxide-semiconductor) image sensor. The optical axis of the image sensor 121 and the optical axis of the image pickup lens 122 coincide with each other. The optical axes of the image sensor 121 and the image pickup lens 122 are located behind the optical axis C1 of the focused light L4 (the axis passing through the center of the Fresnel lens 113). With such an arrangement, the image sensor 121 receives the light that is a part of the focused light L4 and has passed through the region of the inspection target T in front of the optical axis C1 via the image pickup lens 122. do. Therefore, the line sensor camera 120 captures an image of the region in front of the optical axis C1 in the illumination region illuminated by the focused light L4 in the inspection target T by the above-mentioned light reception by the image sensor 121. The line sensor camera 120 outputs the captured image obtained by imaging to the control unit 134.

(Relationship between the focused light L4 and the imaging range H of the line sensor camera 120)
Here, the relationship between the focused light L4 and the imaging range H imaged by the line sensor camera 120 will be described with reference to FIG.

The light source 111 emits long strip-shaped (rectangular) light in the left-right direction when viewed from above by a plurality of LEDs 111A arranged in the left-right direction. The louver 112 is also long in the left-right direction, and the parallel light L3 emitted from the louver 112 is also a strip-shaped light that is long in the left-right direction when viewed from above. Therefore, as shown in FIG. 6, the focused light L4 at the position of the inspection target T in the vertical direction also has a long strip shape in the horizontal direction when viewed from above.

As shown in FIG. 6, the imaging range H imaged by the line sensor camera 120 is a line-shaped region (long and thin strip-shaped region extending in the left-right direction) extending in the left-right direction, and the inspection target T is all in the left-right direction. It is stored. Here, the Fresnel lens 113 has an optical characteristic that the brightness of the light emitted from the center (that is, the light on the optical axis C1) is extremely higher than the brightness of the light emitted from other portions. Therefore, in this embodiment, the imaging range H imaged by the line sensor camera 120 is a region in front of the optical axis C1, that is, the Fresnel lens 113 so that a high-luminance portion is not reflected in the captured image. It is set in an area that is far forward from the area illuminated by the light emitted from the center of the lens. The center of the imaging range H in the left-right direction coincides with the position of the optical axis C1 in the left-right direction.

The captured image captured by the line sensor camera 120 includes a region defined by the imaging range H in the region R1 illuminated by the focused light L4 in the inspection target T (that is, the region through which the focused light L4 is transmitted). R2 is reflected. Since the region R2 is defined by the imaging range H, the region R2 is shifted forward with respect to the region illuminated by the light emitted from the center of the Fresnel lens 113. Since the region R2 includes the left side and the right side of the inspection target T, the entire left-right direction of the inspection target T is captured in the captured image.

The imaging range H is set, for example, by adjusting the position of the line sensor camera 120. For example, first, the optical axis of the image sensor 121 and the image pickup lens 122 (the center of the image pickup range H) and the optical axis C1 (the center of the Fresnel lens 113) are aligned with each other. After that, while checking the captured image captured by the line sensor camera 120, the line sensor camera 120 is moved backward so that the region having higher brightness than the surroundings deviates from the captured image. The position where the region deviates from the image captured by the line sensor camera 120, or a position further deviated from the image captured by the line sensor camera 120 by a predetermined distance in consideration of vibration of the line sensor camera 120 is defined as the imaging position of the line sensor camera 120, and the line is set at that position. The sensor camera 120 is fixed. As a result, the line sensor camera 120 can image a line-shaped region of the inspection target T that avoids the region illuminated by the light emitted from the center of the Fresnel lens 113.

(Defect inspection process)
The control unit 134 (processor) performs the following processing as the defect inspection processing.

The control unit 134 controls the lighting device 110 and keeps it on all the time. Further, the control unit 134 controls the line sensor camera 120. Under the control of the control unit 134, the line sensor camera 120 continuously images the inspection target T illuminated by the lighting device 110 and moving forward. The line sensor camera 120 sequentially supplies the captured image (a line-shaped image in which the region R2 is captured) obtained for each imaging to the control unit 134.

The control unit 134 synthesizes a plurality of captured images sequentially supplied from the line sensor camera 120 to generate one image (hereinafter, also referred to as a composite image). Based on the composite image, the control unit 134 inspects whether or not the inspection target T shown in the composite image has a defect (details will be described later). After that, among the plurality of captured images, the oldest supplied (captured) captured image is removed, and the plurality of captured images to which the newly supplied (captured) captured image is added are combined to form one image. A composite image is generated, and based on the composite image, an inspection is performed to see if the inspection target T shown in the composite image has a defect. After that, the generation of one composite image and the inspection based on the generated composite image are repeated. As a result, the inspection target T moving forward can be continuously inspected for defects.

When the inspection target T has a defect, the defect scatters or reflects the focused light L4, so that the defect appears darker than the portion without the defect (the portion transmitting the condensed light L4). Therefore, the control unit 134 inspects whether or not the inspection target T shown in the composite image has a defect, for example, as follows. The control unit 134 performs a binarization process on the composite image according to a predetermined threshold value, and generates a binarized image in which the bright pixels in the captured image are “white” and the dark pixels are “black”. The control unit 134 performs a labeling process on the binarized image to specify an area of a mass in which "black" pixels are gathered. If the number of pixels in the specified block region is equal to or greater than a predetermined threshold value, the control unit 134 determines that the block region is a region in which defects are reflected and determines that there is a defect.

When the control unit 134 determines that there is a defect, the control unit 134 notifies the user to that effect via the display unit 131 or the like.

(Explanation of the effect of this embodiment)
In this embodiment, the parallel light L3 is extracted from the diffused light L2 from the light source 111 by the louver 112 having a honeycomb structure, and the parallel light L3 is focused on the line sensor camera 120 by the Fresnel lens 113. Since the inspection target T is illuminated by the condensed light L4 focused on the line sensor camera 120, it is preferably illuminated. Specifically, the parallel light L3 eliminates inconveniences such as a different appearance in the captured image depending on the direction of the defect. Further, if the Fresnel lens 113 is not provided, the parallel light L3 transmitted through the region near the boundary of the imaging range H originally desired to be imaged cannot be incident on the line sensor camera 120, and the region near the boundary becomes dark in the captured image. However, such inconvenience can be prevented by the focused light L4.

Further, in this embodiment, a honeycomb structure is adopted as the structure of the louver 112, and the parallel light L3 is focused by the Fresnel lens 113. The honeycomb-structured louver 112 can be manufactured relatively easily (including design; the same applies hereinafter). For example, the louver 112 can be easily manufactured by a mold or the like. Further, the Fresnel lens 113 has been known conventionally and is known to be easily manufactured. Therefore, the illuminating device 110 of this embodiment can suitably illuminate the inspection target T and can be easily manufactured.

The louver of Patent Document 1 has a plurality of through holes having different central axis directions because it is curved, but the louver having such a plurality of through holes has a complicated shape and cannot be easily manufactured. For example, the louver cannot be manufactured with a mold or the like. Further, the calculation of the value of the curvature curvature of the louver is complicated, and it is not easy to manufacture the louver with the calculated curvature. Further, in order to appropriately inject the illumination light into each of the plurality of through holes of the louver, it is necessary to form the light source so that the central axis of each through hole and the optical axis of the light incident in each through hole are aligned with each other. However, it is not easy to form such a light source. Since the louver 112 has a rectangular parallelepiped shape, each through hole 112A has the same shape, and the central axis 112B is parallel, the louver 112 does not have the curved structure as in Patent Document 1, and does not have the above-mentioned inconvenience and is easy to use with a mold or the like. Can be manufactured.

The Frenel lens 113 can suitably focus the parallel light L3, but as described above, the brightness of the light emitted from the center thereof (that is, the light passing through the optical axis C1) is the light emitted from other portions. It has extremely higher optical characteristics than the brightness of. Therefore, in this embodiment, the imaging range H of the line sensor camera 120 is set to a range avoiding the position where the optical axis C1 passes (FIG. 6). That is, the line sensor camera 120 captures a line-shaped region deviated from the region illuminated by the light emitted from the center of the Fresnel lens 113. Therefore, the line sensor camera 120 can obtain a suitable captured image without capturing a portion having extremely high brightness. This preferably leads to the inspection for the presence or absence of defects.

Further, in this embodiment, the line sensor camera 120 is provided so that the center of the imaging range H of the line sensor camera 120 in the left-right direction coincides with the position of the optical axis C1 in the left-right direction. As a result, the image pickup by the line sensor camera 120 is performed under optically suitable conditions. For example, it is possible to prevent the occurrence of inconvenience such that a dark portion is generated in the left-right direction and uneven brightness is generated. Therefore, an imaging image suitable for inspection for the presence or absence of defects can be obtained.

(Modification example)
The present invention is not limited to the above-described embodiment, and various modifications (including deletion of components) are possible with respect to the above-described embodiment. Hereinafter, the modified examples will be described, but at least a part of each modified example may be combined.

(Modification example 1)
The light source 111 may be, for example, a combination of a diffuser plate and a fluorescent tube, or a combination of a light guide member and various lamps (halogen lamp, xenon lamp, etc.).

(Modification 2)
The structure of the louver 112 is not limited to the honeycomb structure, and the shape of the through hole 112A may be changed to, for example, a square prism, a triangular prism, or a cylinder. In order to extract the parallel light L3, each through hole 112A is preferably arranged in a matrix shape (a honeycomb structure is also an example) in which a plurality of the through holes 112A are arranged in the front-rear direction and a plurality of the through holes 112A are arranged in the left-right direction. Further, the louver 112 may be a stack of a plurality of structures having through holes 112A having different shapes in the vertical direction.

(Modification example 3)
Instead of the Fresnel lens 113, another condenser lens (for example, an aspherical lens) or the like may be adopted. Further, the Fresnel lens 113 may be used as it is in a circular shape without being cut. It is also possible to use a telecentric lens as the image pickup lens 122 without using the condenser lens. However, if a telecentric lens is used instead of the condenser lens, the image pickup lens 122 becomes large and the cost increases. From this point of view, it is better to use a condenser lens.

(Modification example 4)
The line sensor camera 120 may image the inspection target T in a range avoiding the region illuminated by the light emitted from the center of the Fresnel lens 113 (in the above embodiment, the position where the optical axis C1 passes). Therefore, the imaging range H may be located behind the optical axis C1. In this case, in the setting of the imaging range H, the line sensor camera 120 is moved forward. The image pickup range H may be set by shifting the optical axis of the image sensor 121 while keeping the optical axis of the image pickup lens 122 and the optical axis C1 aligned with each other.

(Modification 5)
When the inspection target T is large, a plurality of line sensor cameras 120 may be provided. In this case, for example, as shown in FIGS. 7 and 8, a light source 111 and a louver 112 having a length of 120 minutes in the left-right direction of a plurality of line sensor cameras are prepared, and a plurality of Fresnel lenses 113 are mounted on the left and right. They are arranged in the direction, and a plurality of line sensor cameras 120 are arranged above the line sensor cameras 120 so as to have a one-to-one correspondence with each Fresnel lens. The Fresnel lens 113 is arranged on the upper surface of the louver 112. Here, a set including one Fresnel lens 113 and a line sensor camera 120 is also referred to as a unit U. With the above configuration, the units U are arranged in the left-right direction. Further, the plurality of units U, the light source 111, and the louver 112 are arranged in a plurality of rows (here, two rows) in the front-rear direction. As shown in FIG. 8, the units U arranged in a plurality of rows are preferably arranged alternately in the left-right direction. The unit U may be arranged so that the imaging range H of the unit U in the first row and the imaging range H of the unit U in the second row overlap in the left-right direction (FIG. 9 (A)). The unit U may be arranged so that the position of the end portion of the imaging range H of the unit U and the position of the imaging range H of the unit U in the second row coincide with each other in the left-right direction (FIG. 9B). ). In the former case, the unit U can be easily arranged. On the other hand, in the latter case, a composite image can be easily generated. According to the modification 5, the entire inspection target T can be imaged as a whole, and a composite image suitable for defect inspection can be obtained. The lighting device 110 may be prepared separately for each of the line sensor cameras 120 (the louver 112 and the like may not be shared).

(Modification 6)
As shown in FIG. 10, the illuminating device 110 has a light-shielding member 117A and a light-shielding member 117A that shields through holes 112A (through holes 112A not covered by the Fresnel lens 113) in front of and behind the Fresnel lens 113 on the upper surface of the louver 112. 117B may be provided. Although the light-shielding members 117A and 117B are partially cut out in FIG. 10, they have substantially the same shape. The light-shielding members 117A and 117B have a rectangular shape elongated in the left-right direction, and are arranged at positions in contact with the Fresnel lens 113 arranged on the upper surface of the louver 112. As a result, it is possible to restrict the movement of the Fresnel lens 113 in the front-rear direction while blocking the light from the extra portion of the louver 112. Further, by enabling the Fresnel lens 113 to move in the left-right direction, the relative position of the line sensor camera 120 and the Fresnel lens 113 in the left-right direction can be adjusted by moving the Fresnel lens 113 to the left and right. Specifically, by moving the Fresnel lens 113, the center of the imaging range H of the line sensor camera 120 in the left-right direction can be aligned with the position of the optical axis C1 in the left-right direction. The light emitted from the louver 112 and emitted from a position deviated from the Fresnel lens 113 travels straight upward and is not incident on the line sensor camera 120, so that the light emitted from the line sensor camera 120 does not need to be shielded as described above. However, if the length of the louver 112 in the vertical direction is short as described later, the directivity of light from the louver 112 deteriorates, so it is better to shield the light. It should be noted that such a configuration can be applied even when the Fresnel lens 113 and the line sensor camera 120 are one, as in the above embodiment.

(Modification 7)
The inspection target T is not limited to the transparent film, but may be a glass substrate, a circuit pattern, a wafer, or the like. The inspection target T may reflect the illumination light from the illumination device 110, and the line sensor camera 120 may receive the reflected light to image the inspection target T. The defect to be detected is not limited to scratches and the like, and various defects can be targeted. Examples of defects include pinholes, foreign matter, poor patterns, and streaky scratches. The defect inspection device 100 may be, for example, one that is arranged in various production lines and sequentially inspects products manufactured upstream.

(Modification 8)
The louver 112 emits only parallel light L3 in an optically ideal case and cuts other light (restricts (that is, prohibits) the passage of all the other light), but actually parallel light L3. Light other than is also emitted. This is because there is light (unintended light) that does not hit the inner wall of the through hole 112A and passes through the through hole 112A, although it is not the light that travels along the central axis 112B. The amount of unintended light depends on the thickness (length in the vertical direction) of the louver 112 when the through hole 112A has the same shape. Therefore, the directivity of the light emitted from the louver 112 (ideally, only parallel light) depends on the thickness of the louver 112. The thicker the louver 112, the better the directivity of the light emitted from the louver 112 (however, the total amount of the emitted light is small). When the inspection target T originally has irregularities or the like, if the directivity of the light emitted from the louver 112 is good (that is, when it is close to parallel light), the irregularities are clearly reflected in the captured image, resulting in defects and irregularities. It becomes difficult to distinguish, and defects may not be detected well. In such a case, if the directivity of the light emitted from the louver 112 is deteriorated, the unevenness may be inconspicuous in the captured image and the defect may be easily detected. Further, when the inspection target T is flat, it is preferable to improve the directivity of the light emitted from the louver 112. By improving the directivity of light, the contrast between the defect and other parts can be increased, the accuracy of detecting the defect can be improved, and the false detection of the defect can be prevented. In this way, when manufacturing the defect inspection device 100, the thickness of the louver 112 may be adjusted according to what the inspection target T is.

(Modification 9)
The center of the imaging range H of the line sensor camera 120 may be aligned with the center of the Fresnel lens 113. In this case, a filter (for example, an apodizing filter) that reduces the amount of light transmitted through the center may be arranged between the line sensor camera 120 and the Fresnel lens 113.

(Modification example 10)
Another camera may be adopted instead of the line sensor camera 120. For example, an area sensor camera may be adopted. It is preferable to change the shape and the like of each component constituting the lighting device 110 according to the type of the camera.

100 Defect inspection device 110 Lighting device 111 Light source 111A LED
111C Diffuse plate 112 Louver 112A Through hole 112B Central axis 113 Frenel lens 117A Light-shielding member 117B Light-shielding member 120 Line sensor camera 121 Image sensor 122 Imaging lens 130 Computer L1 Light emitted by LED L2 Diffuse light L3 Parallel light L4 Condensed light L10 1 light L11 2nd light H Imaging range C1 Optical axis T Inspection target R1 Area illuminated by condensed light in the inspection target R2 Area R1 of the area R1 partitioned by the imaging range H U unit

Claims (5)

The lighting unit that illuminates the inspection target and
A camera that captures the inspection target illuminated by the lighting unit, and
It is provided with an inspection unit that inspects the presence or absence of defects in the inspection target based on the captured image of the inspection target captured by the camera.
The lighting unit
A light source that emits light to illuminate the inspection target,
A second through hole having parallel central axes that allows the first light emitted from the light source to pass through the first light traveling in the central axis direction and traveling in a direction different from the central axis direction. A louver with multiple through-holes that restrict the passage of light,
A condensing lens that condenses the first light that has passed through the plurality of through holes to the camera.
Bei to give a,
The camera is a line sensor camera that captures a line-shaped area extending in the left-right direction.
The condenser lens is a Fresnel lens.
The line sensor camera captures the line-shaped region deviated from the region illuminated by the light emitted from the center of the Fresnel lens in the inspection target.
Defect inspection equipment. The center of the line-shaped region in the left-right direction coincides with the optical axis passing through the center of the Fresnel lens in the left-right direction.
The defect inspection apparatus according to claim 1. The Fresnel lens is placed on the upper surface of the louver.
The illumination unit includes a light-shielding member on the upper surface of the louver that closes the through hole that is not covered by the Fresnel lens and regulates the movement of the Fresnel lens in the front-rear direction.
The defect inspection apparatus according to claim 1 or 2. A plurality of units including the condenser lens and the camera are provided.
It said plurality of units includes a plurality of first units arranged in a first row, and a plurality of second units arranged in the first second of parallel rows and columns,
Each of the plurality of first units and each of the plurality of second units are arranged alternately.
The defect inspection apparatus according to any one of claims 1 to 3. A manufacturing method for manufacturing the defect inspection apparatus according to any one of claims 1 to 4.
The length of the louver in the central axis direction is set according to the inspection target.
Manufacturing method of defect inspection equipment.

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