JPH08178864A - Defect inspecition devece for lenticular lens sheet - Google Patents

Abstract

PURPOSE: To provide an automatic inspection device which can cope with the warpage of lenticular lens sheet. CONSTITUTION: The defect inspection device is provided with one or a plurality of linear region image pick-up means 110 for picking up the image of a specific linear region of a lenticular sheet straddling over the width in the direction nearly a right angle to the traveling direction of at least a sheet of plate of or continuous plate-shaped lenticular lens sheet 150 by a reflection dark field light, a lighting means 120 for supplying the reflection dark field lighting for picking up image for the linear region image pickup means, and an image processing means 130 for detecting a defect based on the image data obtained by the linear region image processing means. The defect inspection device for detecting the defect of the lentcular lens sheet while moving the lenticular lens sheet at a certain speed is provided with a calibration means 140 for calibrating the warpage of the lenticulation lens to be inspected at least near an image pickup visual field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus for a lenticular lens sheet used for a transmission type projection screen, and more particularly, to an automatic inline detection of white defects in a black stripe portion of a lenticular lens sheet. Regarding inspection equipment.

[0002]

2. Description of the Related Art A lenticular lens sheet for a transmissive projection screen is made of a transparent resin such as an acrylic resin or a polycarbonate resin, and as shown in FIG. 8, generally, the light source side and the light emitting surface when used as a screen. Lenticular lenses 810 and 820 are provided on the side to increase the contrast and sharpen the image.
A light-shielding stripe portion called a black stripe 830 is arranged between the lenticular lenses 810 on the light emitting surface side. The light-shielding stripe portion called the black stripe is a lenticular lens sheet 80.
0 is extruded and molded with acrylic resin, polycarbonate resin, etc., and then the light-shielding film part is printed while passing between the rolls. A missing or damaged portion (hereinafter, referred to as a white defect) occurs. For this reason, when it is used as a screen, it is a cause of impairing the contrast and sharpness of the image due to the reflected light from the outside, and it is necessary to identify the location and correct it, or select and remove the screen. Of course, it was necessary to specify the location of this white defect portion.

Conventionally, as a visual inspection method for detecting the above-mentioned white defects of a lenticular lens sheet, a method by human eyes has been adopted, but in recent years, a lenticular lens sheet for a transmission type projection screen has a high quality. With the increasing demand for higher quality and mass production, the conventional naked-eye inspection has differences in people and reproducibility. Therefore, inexpensive automatic inspection equipment has been demanded. Also, for mass production, inspection by an automated device has been required. In order to deal with this, the present inventors have taken an image of a predetermined linear region of the lenticular lens sheet 940 that straddles at least a width in a direction substantially perpendicular to the moving direction of the lenticular lens sheet 940, as shown in FIG. A CCD line sensor camera 910, which is a linear area imaging unit for capturing an image with reflected dark-field light as a field of view 950, a light source 920 that is an illumination unit that supplies reflected dark-field illumination for imaging, and a linear region. An image processing hand portion 93 for detecting defects based on image data obtained by the image pickup means is provided, and a continuous plate-shaped lenticular lens sheet 940 is moved at a constant speed in the lenticular lens direction (black stripe direction). While moving the lenticular lens sheet 9
Defect inspection devices have been proposed that detect 40 defects.

However, the lenticular lens sheet itself after black stripe coating may be warped, which makes it difficult to detect defects in the above defect inspection apparatus. In particular, in the case of a sheet-shaped lenticular lens sheet after applying a black stripe, it may be used in combination with a Fresnel lens sheet, and in order to improve the adhesion (prevention of floating) with the Fresnel lens sheet, the lenticular lens sheet It may be in a state of being convexly curved to the side where the black stripe is not formed. In this case, if you put the lenticular lens sheet on a flat surface,
As shown in FIG. 5, the lenticular lens sheet 500.
There is a case where the sled portion 510 remains at the end of the sheet, which makes it difficult to automate the inspection at the end.

[0005]

In this way, the lenticular lens is subjected to reflection dark-field illumination, and the image picked up by the linear region image pickup means is subjected to image processing to produce white defects on the black stripes of the sample on the production line (in-line). Even in the automatic inspection method that is detected by, while higher quality and mass production are required, an inspection device that can cope with the warp of the lenticular lens sheet has been required.
Under the circumstances, the present invention provides an automatic inspection in which a lenticular lens is subjected to reflective dark-field illumination and image processing is performed on an image captured by a linear area imaging unit to detect a white defect in a black stripe portion of the lenticular lens. In the method, it is an object of the present invention to provide an automatic inspection device capable of dealing with the warp of the lenticular lens sheet.

[0006]

A defect inspection apparatus for a lenticular lens sheet according to the present invention extends at least across a width of a sheet-shaped or continuous plate-shaped lenticular lens sheet in a direction substantially perpendicular to the moving direction. One or a plurality of linear area imaging means for imaging a predetermined linear area of the lenticular lens sheet with reflected dark field light, and reflective dark field illumination for imaging the linear area imaging means. An illumination means for supplying and an image processing means for detecting a defect based on the image data obtained by the linear area image pickup means are provided, and the defect of the lenticular lens sheet is moved while moving the lenticular lens sheet at a constant speed. A sled for correcting a sled of a lenticular lens sheet which is an object to be inspected at least near an imaging visual field. That it comprises a positive means is characterized in. And the above-mentioned warp correction means is characterized in that it presses compressed air (compressed air) against a member that forms a predetermined flat surface by applying a lenticular lens sheet, and the above-mentioned warp correction means, It is characterized in that air is sucked and the lenticular lens sheet is pressed against a member forming a predetermined flat surface. Here, the member forming the flat surface is not limited to the one such as the conveyor belt having the flat surface 180A shown in FIGS. 1 and 2, and the individual surfaces in contact with the supporting lenticular lens sheet are the same. It refers to a member that lies within a flat surface. Further, the above-mentioned inspection device is an inspection device with the black stripe surface side facing upward and the lenticular lens sheet placed on a flat surface such as a conveyor belt.

[0007]

The defect inspection apparatus for a lenticular lens sheet according to the present invention is configured as described above to illuminate the lenticular lens sheet with reflected dark field, and to perform image processing on the image captured by the linear region imaging means. In the automatic inspection method for detecting defects in the sample, it is possible to cope with the warp of the lenticular lens sheet. More specifically, at least in the vicinity of the imaging field of view, a warp correction unit that corrects the warp of the lenticular lens sheet that is the object to be inspected is provided, which enables a reliable inspection that can cope with the warp of the lenticular lens. The warp correcting means applies compressed air (compressed air) to the lenticular lens sheet and presses it against a member that forms a predetermined flat surface, so that inspection can be performed in a non-contact manner with the imaging visual field surface of the lenticular lens sheet. It is also excellent in terms of work and quality. Similarly, the warp correcting means sucks air and presses the lenticular lens sheet against a member forming a predetermined flat surface, so that inspection can be performed in a non-contact manner with the imaging visual field surface of the lenticular lens sheet. It is also excellent in terms of work and quality.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings of an embodiment of a defect inspection apparatus for a lenticular lens sheet according to the present invention. First, Example 1 of the defect inspection apparatus for a lenticular lens sheet of the present invention will be described. FIG. 1 is a diagram showing a schematic configuration of a defect inspection apparatus for a lenticular lens sheet of Example 1, and FIG. 2 is a diagram showing a main part of this example. 1 and 2, 100 is a defect inspection apparatus, 110 is a CCD line sensor camera, 120 is a light source, 130 is an image processing unit, 140
Is a compressed air (compressed air) introduction tube, 150 is a lenticular lens sheet, 160 is an imaging field of view, 170 is a sled portion, 18
Reference numeral 0 indicates a conveyor belt, and 180A indicates a flat surface. The defect inspection apparatus for the lenticular lens sheet of this embodiment is shown in FIG.
An apparatus for inspecting a white defect in a black stripe portion of a lenticular lens sheet shown in FIG. 1 to detect a defect by performing image processing on image data (signal) captured by the CCD line sensor camera 110 in a reflective dark field. To do. The defect apparatus of the present embodiment blows compressed air from the compressed air introduction tube 140 shown in FIG. 1 to the vicinity of the imaging field of view 160 on the sled portion at the time of defect detection, and conveys the entire lenticular lens sheet to a conveyor belt 180 having a flat surface 180A.
In particular, even if the lenticular lens sheet 500 in the form of a single sheet after applying the black stripe shown in FIG. The warp is corrected so that there is no influence of the portion, and the defect is detected as a flat shape.

The correcting means in the inspection apparatus according to the first embodiment will be further briefly described with reference to FIG. FIG. 2A is a diagram in the case where the sled portion 170 is not in the vicinity of the imaging visual field 160 for defect detection, and the sled portion 170 of the lenticular lens sheet 150 is in a state of floating from the flat surface 180A of the conveyor belt 180. If the image pickup field 160 of the CCD line sensor camera 110 is reached in this state, the image pickup of the sled portion 170 is out of focus, which makes it difficult to detect defects. In the case of the apparatus of the present embodiment, as shown in FIG. 2B, when the sled portion 170 comes near the imaging field of view 140 for defect detection, compressed air is introduced from the compressed air introduction pipe 140 to the sled portion 170. Since it is blown, the sled portion 170 is pressed against the flat surface 180A of the conveyor belt 180, and when the sled portion 170 reaches the imaging visual field 160 of the CCD line sensor camera 110,
The image is in focus. In this way, the warp at the end of the lenticular lens sheet 150 is corrected by the compressed air from the compressed air introduction pipe 140 and the flat surface of the conveyor belt 180. As a member for holding the lenticular lens sheet 150 pressed by compressed air flat,
As described above, it is easy to use the one using the flat surface 180A of the conveyor belt 180 itself, but the present invention is not limited to this, and it is a member that forms a predetermined flat surface and conveys the lenticular lens sheet 150. It should be done without any trouble. In order to form a flat surface on the conveyor belt itself, a flat member for holding the conveyor belt along the conveyor belt may be provided.

Image processing is performed by the CCD line sensor camera 1
A spatial filter is used for the image data (signal) obtained in 10 to perform a first-order differentiation process or a second-order differentiation process. Regarding the result obtained by this image process,
Further, slicing processing is performed, and those exceeding a predetermined threshold are detected as defects.

Next, the CCD line sensor camera 110
The process of performing image processing on the image data of the image pickup visual field 160 obtained by the image pickup by the image processing unit 130 shown in FIG. 1 to detect a defect will be further described. The image processing unit 130 shown in FIG. 2 has an imaging visual field 16 obtained by imaging.
The image signal of 0 is subjected to first-order differential processing or second-order differential processing to obtain a change in the signal to identify a defect. The differential processing here uses a filter having an element array for each sampling. In addition, the product-sum operation is performed. Note that, here, using the image data P (X _ij ) and the spatial filter table W (i, j) obtained from the image pickup means, the product-sum calculation of P (X _ij ) and W (i, j) is performed. What is performed is called a filtering process, and the table W (i, j) used in this process is called a filter, and is generally called a differential filter or a space filter. The differential filter for the array of pixel data in the Y direction is represented as shown in FIG. 7 by the weight of the pixel of interest and the pixels before and after it in the product-sum operation and the array direction. For example, with respect to the image data P (Y _n ), as shown in FIG.
2, + 1) and spatial filter table (weight table)
By setting, it is possible to perform the second-order differential processing in which smoothing processing is performed for two pixels in the Y direction. When the pixel of interest is Y _n , the product sum operation S _n between the image data P (Y _n ) and the spatial filter table is (+1) × Y _n−1 + (− 2) × Y _n
It becomes + (+ 1) × Y _{n + 1} . Further, as shown in FIG. 4B, the primary differentiation process can be performed by setting the spatial filter table (weight table) to (-1, + 1).

The image processing unit 130 detects a defect in the image data (signal) of the CCD line sensor camera 110 by the following processing. FIG. 7 is a diagram for explaining image processing on image data (signal) obtained from one CCD line sensor camera. In FIG.
The second derivative is a product-sum calculation with a spatial filter table for each pixel data at the same position between lines with respect to line data obtained by sampling with a CCD line sensor camera, and a predetermined number of consecutive Line data obtained by sampling is accumulated, and product-sum calculation is performed between the line data. In the case of FIG. 7, this process is performed between 9 line data, but every time new line data is sampled, the old line data is removed gradually and this process is always performed with 9 line data. ) _Represents the pixel data at the i-th position in the j-th line data, and when the pixel data at the M-th position is subjected to the multiply-accumulate operation between the lines, the results of the secondary differential processing and the primary differential processing are respectively Figure 7
(B), as shown in FIG. 7 (c). Slice processing is further performed on each of the calculation results of the secondary differential processing or the calculation results of the primary differential processing thus obtained, and defects exceeding a predetermined threshold value are detected. Here, the line data is a visual field including a predetermined width on a straight line on the sheet surface, which is obtained by the image pickup means (CCD line sensor camera) and extends across a width in a direction substantially orthogonal to the moving direction of the lenticular lens sheet. Of the imaged data in one sampling, the data corresponding to the entire predetermined width is described.

In the above-described embodiment, the image data is obtained by capturing an image of the predetermined area required to obtain the image data (signal) of the sample (lenticular lens sheet) with one CCD line sensor camera. If the sample (lenticular lens sheet) to be inspected is large, it may be divided by a plurality of CCD line sensor cameras to be imaged and the image data (signal) of the necessary predetermined area may be obtained together.

Next, a second embodiment of the lenticular lens sheet defect inspection apparatus of the present invention will be described. FIG. 3 is a diagram showing a schematic configuration of the lenticular lens sheet defect inspection device of the second embodiment, and FIG. 4 is a diagram showing a main part of the present embodiment. In FIG. 3, 200 is a defect inspection device, 210A and 21.
0B is a CCD line sensor camera, 220 is a light source, and 23
Reference numeral 0 is an image processing unit, 240 is an air suction tube, 250 is a lenticular lens sheet, 260A and 260B are imaging fields of view, 270 is a sled portion, 280 is a conveyor belt, and 280A is a flat surface. The defect inspection apparatus of this embodiment is shown in FIG.
Imaging field 2 of the lenticular lens sheet 250 shown in FIG.
Air is sucked in the vicinity of the imaging visual fields 260A and 260B by the air suction tube 240 with respect to the surface facing the 60 side surface, and the entire lenticular lens sheet is fixed by the flat surface 280A of the conveyor belt 280 having a flat surface. As in the case of Example 1, even when the lenticular lens sheet 500 is provided with the sled portion 510 at the end, the sled is corrected and flattened so as not to be affected by the sled portion. Defects are detected.

The correcting means in the inspection apparatus according to the second embodiment will be further briefly described with reference to FIG. FIG. 4A is a diagram when the sled portion 170 is not in the vicinity of the imaging visual fields 260A and 260B for defect detection, and the sled portion 270 of the lenticular lens sheet 250 is the conveyor belt 2.
80 is in a state of floating from the flat surface 280A. If this state is left, the CCD line sensor cameras 210A, 21
When the image pickup fields 260A and 260B of 0B are reached, the image pickup of the sled portion 270 is out of focus, which makes it difficult to detect defects. In the case of the apparatus of this embodiment, as shown in FIG. 4B, when the sled portion 270 comes near the imaging visual field 240 for defect detection, the sled portion 270 is sucked by the air suction tube 240. , Sled part 2
70 is pressed against the flat surface 280A of the conveyor belt 280, and the sled portion 270 is attached to the CCD line sensor camera 210.
When the image pickup fields 260A and 260B of A and 210B are reached, the image pickup is focused. In this way, suction by the air suction pipe 240 and the flat surface 180 of the conveyor belt 180 are performed.
By A, the warp at the end of the lenticular lens sheet 250 is corrected. The conveyor belt in this embodiment is formed by arranging a plurality of belt-shaped belts in a moving direction, and the lenticular lens sheet is sucked from the gap between the belt-shaped belts to correct the sled portion 270. As the member that holds the sucked lenticular lens sheet 250 flat, a member that uses the flat surface 280A of the conveyor belt 280 itself is used as in the first embodiment. The member for holding the lenticular lens sheet 250 flat may be any member as long as it can form a predetermined flat surface and can carry the lenticular lens sheet 250 smoothly.

In the case of the present embodiment, the CCD line sensor cameras 210A and 210B obtain image data (signals) of the imaging visual fields 260A and 260B, respectively, and use them as signals in a predetermined visual field region. The image processing performed by the image processing unit 230 is basically the same as that in the first embodiment.

[0017]

As described above, the present invention provides an automatic inspection apparatus for illuminating a lenticular lens sheet with reflection dark-field illumination and performing image processing on an image captured by the linear region imaging means to detect a defect in a sample. (EN) It is possible to provide a black stripe white defect detection device for a lenticular lens sheet that can eliminate the influence of warpage of a continuous sheet-shaped lenticular lens sheet that is not a sheet-like plate.

[Brief description of drawings]

FIG. 1 is a schematic overall view of a defect detection device for a lenticular lens sheet of Example 1.

FIG. 2 is a diagram for explaining a main part of a defect detection device for a lenticular lens sheet according to a first embodiment.

3 is a schematic overall view of a lenticular lens sheet defect detection device of Example 2. FIG.

FIG. 4 is a diagram for explaining a main part of a defect detection device for a lenticular lens sheet according to a second embodiment.

FIG. 5 is a diagram for explaining a warp of a lenticular lens sheet.

FIG. 6 is a diagram showing a space filter.

FIG. 7 is a diagram for explaining image processing in the embodiment.

FIG. 8 is a diagram showing defects in a lenticular lens sheet.

FIG. 9 is a schematic view of an apparatus for explaining a conventional defect inspection method.

[Explanation of symbols]

100, 200 Defect inspection apparatus 110, 210 CCD line sensor camera 120, 220 Illuminating means (light source) 130, 230 Image processing section 140 Compressed air introducing tube 150, 250 Lenticular lens sheet 160, 260 Imaging field of view 180, 280 Conveying belt 180A, 280A Flat surface 240 Air suction tube 510 Sled portion 800 Lenticular lens sheet 810, 820 Lenticular lens portion 830 Black stripe 910 CCD line sensor camera 920 Light source 930 Image processing portion 940 Lenticular lens sheet 950 Imaging field of view

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Claims (3)

[Claims] 1. A predetermined linear region of at least a sheet-shaped or continuous plate-shaped lenticular lens sheet that extends across a width in a direction substantially perpendicular to the moving direction of the lenticular lens sheet by reflected dark-field light. One or a plurality of linear area imaging means for imaging, an illuminating means for supplying the linear area imaging means with reflected dark field illumination for imaging, and an image obtained by the linear area imaging means Based on the data, equipped with an image processing means for detecting a defect, while moving the lenticular lens sheet at a constant speed, a defect inspection device for detecting a defect of the lenticular lens sheet, at least in the vicinity of the imaging field of view, Defects in the lenticular lens sheet, characterized by including warp correction means for correcting the warp of the lenticular lens sheet as the inspection object Inspection device. 2. The defect inspection apparatus for a lenticular lens sheet according to claim 1, wherein the warp correcting means presses compressed air against a member that forms a predetermined flat surface on the lenticular lens sheet. 3. The defect inspection apparatus for a lenticular lens sheet according to claim 1, wherein the warp correcting means sucks air and presses the lenticular lens sheet against a member forming a predetermined flat surface. .