JP3324018B2 - Lenticular lens sheet defect inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting the appearance of a lenticular lens sheet used for a transmission type projection screen, and more particularly to a method for detecting a defect of a lenticular lens sheet in-line and going off-line as necessary. The present invention relates to an automatic inspection device capable of retracting and moving.

[0002]

2. Description of the Related Art A lenticular lens sheet for a transmission type projection screen is made of a transparent resin such as an acrylic resin or a polycarbonate resin, and is manufactured by extrusion molding. Local changes in appearance, that is, foreign matters and bubbles inside the resin, stains and scratches on the resin outer surface, and the like occur. Most of these changes in the appearance of the curved part, when the lenticular lens sheet is used as a screen, locally change the light transmittance (light transmission amount) and impair the uniformity.
It was necessary to sort out and remove as an appearance defect. When used as a screen, most of it becomes dark in a curved portion, and is called a black defect. FIG. 7A is a cross-sectional view of the lenticular lens sheet. As shown here, black defects occur at various locations inside the resin of the lenticular lens sheet 700. Exceptionally, it may be locally bright. As shown in FIG. 7, a lenticular lens sheet 700 for a transmission type projection screen generally has lenticular lenses 710 and 711 on a light source side and a light emitting surface side when used as a screen.
In addition, when used as a screen, a light-shielding stripe portion called a black stripe 730 is provided between the lenticular lenses 710 on the light-emitting surface side to increase the contrast and make the image sharp. The light-shielding stripe portion called this black stripe is formed by extruding a lenticular lens sheet with acrylic resin, polycarbonate resin, etc.,
The light-shielding film is printed and printed while passing between the rolls, and the process of producing the light-shielding film and the partially missing or damaged portions (hereinafter, referred to as white defects) after that are performed. appear. For this reason, when used as a screen, reflected light from the outside is a cause of losing contrast and image sharpness, so it is necessary to identify and correct the location or screen out the screen However, it was necessary to specify the location of the white defect.

Conventionally, a visual inspection method has been adopted as a visual inspection method for detecting the above-mentioned defect of a lenticular lens sheet. However, in recent years, lenticular lens sheets for transmission type projection screens have been increasingly required to have higher quality and mass production. Because of the problem of reproducibility, a compact and inexpensive automatic inspection apparatus which can stably detect a defect instead of manual operation has been required. In addition, an inspection using an automated device has been required for mass production.
Furthermore, in the introduction of the automatic inspection device, it has been required that the automatic inspection device does not hinder the change of the product type without interfering with the production of the lenticular lens. In other words, there has been a demand for an automatic inspection apparatus having a compact structure and capable of being evacuated and moved off-line as needed.

[0004]

As described above, as higher quality and mass production are increasingly demanded, the lenticular lens is illuminated by transmission or reflection in a dark field, and image processing is performed on an image captured by the linear area imaging means. The realization of an automatic inspection for detecting defects in a sample by applying the method has been required.
Under such circumstances, the present invention provides a high-quality, mass-producible, lenticular lens that transmits or reflects dark-field illumination, performs image processing on an image captured by a linear region imaging unit, and performs image processing on the sample. In an automatic inspection apparatus for detecting defects, it is desirable to provide a compact lenticular lens defect inspection apparatus which can be evacuated from a production line (inline) to an off-line when necessary, for example, when changing the production type of a lenticular lens. Things.

[0005]

According to the present invention, there is provided a lenticular lens sheet defect inspection apparatus which extends over at least one straight line on a lenticular lens sheet surface over a width substantially perpendicular to a moving direction of the lenticular lens sheet. One or more linear region imaging means for imaging a predetermined width with transmitted light or reflected dark field light, and one or more linear region imaging means for imaging a lenticular lens, A continuous plate including illumination means for supplying transmitted light illumination and / or reflected dark field illumination for imaging, and image processing means for detecting a defect based on image data obtained by the linear region imaging means; While moving the lenticular lens sheet at a constant speed, detect defects in the lenticular lens sheet by transmitted light or reflected dark field light A defect inspection apparatus, wherein the linear area imaging means and the illuminating means are integrated to form a photographing means, and a moving means for moving the photographing means between a production line and off-line is provided. It is characterized by having. Further, the moving means described above is characterized in that it is moved on a rail by a roller or the like attached to the photographing means. The moving direction of the lenticular lens sheet is the direction of the lenticular lens, that is, the direction of the black stripe 730 in FIG. Here, a production line for continuously producing or inspecting a lenticular lens sheet is referred to as an in-line, and an off-line refers to a place off the in-line.

[0006]

With the lenticular lens sheet defect inspection apparatus of the present invention having the above-described configuration, it is possible to cope with high quality and mass production. An automatic inspection device that performs image processing on an image captured by a means to detect a defect in a sample. The inspection device can be evacuated from a production line (in-line) to offline when necessary. Is possible. Specifically, the linear region imaging means and the illumination means are integrally formed as a photographing means, and the integrated whole is provided with a moving means for moving the whole unit on a rail by a roller. Thus, it is possible to move between the production line and the off-line, and it is almost unnecessary to adjust the imaging unit and the illumination unit.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a lenticular lens sheet defect inspection apparatus according to an embodiment of the present invention. First, a lenticular lens sheet defect inspection apparatus according to a first embodiment of the present invention will be described. The defect inspection apparatus for a lenticular lens sheet according to the first embodiment is a defect inspection apparatus for detecting a defect (black defect) caused by a foreign substance inside the resin, air bubbles, dirt or a scratch on the resin outer surface, and FIG.
1 is a schematic diagram of a lenticular lens sheet defect inspection apparatus of Example 1. FIG. In FIG. 1, reference numeral 100 denotes a lenticular lens sheet defect inspection apparatus; 110, an imaging device in which imaging means and illumination means are integrally fixed; 111, a lenticular lens sheet passage recess; 112, an imaging device support portion; Reference numeral 120 denotes an image processing unit; 130, a continuous plate-shaped lenticular lens sheet; 140, a rail; and 141, a roller.
110a indicates a state where the photographing unit 110 is placed at the in-line position, and 110b indicates a state where it is retracted and placed at the off-line position. As shown in FIG. 1, the lenticular lens sheet defect inspection apparatus 100 according to the present embodiment, when inspecting on a production line (in-line), places the lenticular lens sheet 130 into the lenticular lens sheet passing recess 101 of the photographing apparatus 110. The image is passed at a constant speed, and at the time of passing, a predetermined area of the lenticular lens sheet 130 is photographed by the photographing device 110, an image signal (data) is obtained, and the obtained image signal (data) is processed by the image processing unit 120. And defect detection. Lenticular lens sheet defect inspection apparatus 10 of the present embodiment
FIG. 2 shows a schematic configuration of only the defect detection function of FIG.
Is provided with CCD line sensor cameras 200a, 200b, and 200c as image pickup means shown in FIG. 2 above the lenticular lens sheet passage recess 111, and below the lenticular lens sheet passage recess 111 as shown in FIG. A linear light source 210 as means is provided.
The CCD line sensor camera 200a captures an image of the field of view 240 from the front, and the CCD line sensor camera 200b,
200c captures the imaging field of view 240 by tilting the front from the left and right in the figure. The light source 210 illuminates the lenticular lens sheet 230, which is a sample, for each CCD line sensor camera with transmitted bright field illumination. In FIG. 2, two lines emerging from each CCD line sensor camera represent the field of view taken by each camera. Lenticular lens sheet 230
Assuming that there is a black defect at the position shown in FIG. 7A, the defect A is a defect that is visible from the front of the sample but not obliquely, and the defect B is visible from the oblique direction of the sample but not from the front. defect, C is a defect visible front of the sample, even obliquely either by the camera 200a is defective a to image from the front, the camera 200b to 200c defect B to tilt imaged from diagonally defect C is the camera 200a, 20
Images can be taken from 0b to 200c. still,
Here, the tilt imaging is to form an image of a sample on an image receiving surface of an imaging unit by using a peripheral portion of an angle of view of an imaging unit (lens system) as shown in FIG. The normal imaging refers to imaging that is not tilted imaging. As a transmission type projection screen, one having a lens direction perpendicular to the front and back of the screen, one having a Fresnel lens on the light entrance side, a lenticular lens on the light exit side, and one as shown in FIG. Various combinations of front and back shapes are possible, but basically, if the lenticular lens (convex convex lens) array is provided on the light emitting surface side of the transmission type projection screen, defect detection is performed by this embodiment. Is possible. In the case of a lenticular lens sheet, most defects on the appearance are black defects.
Only R> defects are generally inspected and removed as appearance defects for transmissive projection screens. However, in the defect detection (image processing) described later, a signal obtained by imaging is differentiated, and a defect that becomes bright in a curved portion can be basically detected. In the case of this defect,
In many cases, changes in appearance corresponding to defects cannot be immediately judged.

The photographing means 100 may have a structure using a mirror shown in FIG. 3 in addition to the structure shown in FIG.
The structure shown in FIG. 3 uses a mirror in order to make the photographing means 110 smaller and more compact.
FIG. 3 shows a CCD line sensor camera 3 as an imaging means.
00a, 300b, 300c, light source 310, and mirror 3
FIG. 3 is a diagram showing only a positional relationship between 20a, 320b, and 320c and an imaging field of view 330. By doing so, it is not necessary to enlarge the entire apparatus in order to obtain the imaging field of view 330 in a wide range. In FIG. 3, a CCD line sensor camera 300a captures an image of a field of view 330 from the front,
The CCD line sensor cameras 300b and 300c shift and image the imaging field of view 330 from the left and right. Also in the case of FIG. 3, the defect A, the defect B, and the defect C shown in FIG.
Can be imaged.

Next, the process of detecting a defect in the image processing section 120 of the defect inspection apparatus 100 for a lenticular lens sheet of the present embodiment based on the image data obtained by the imaging in FIGS. 2 and 3 will be briefly described. FIG.
The image processing unit 120 according to the present embodiment, which performs a first-order differentiation process or a second-order differentiation process on an image signal obtained by imaging, obtains a signal change and specifies a defect. The differentiation processing is performed by performing a product-sum operation for each sampling using a filter having an element array. Here, the image data P (X _ij ) obtained from the imaging means and the spatial filter table W (i,
j), and performing a product-sum operation of P (X _ij ) and W (i, j) is called a filtering process. A table W (i, j) used in this process is called a filter, and is generally called a filter. Is called a differential filter or a spatial filter. The differential filter for the Y-direction array of pixel data is represented as shown in FIG. 4 by the weight of the pixel of interest and the pixels before and after it in the product-sum operation and the direction of the array. For example,
As shown in FIG. 4A, (+) is applied to the image data P (Y _n ).
By setting a spatial filter table (weight table) with (1, -2, +1), a second derivative process in which two pixels are smoothed in the Y direction can be performed. If the target pixel was Y _n, product-sum operation S _n of the image data P (Y _n) and the spatial filter _{table, (+ 1) × Y n} -1 + (- 2)
× Y _n + (+ 1) × Y _{n + 1} Also, by setting a spatial filter table (weight table) to (-1, + 1) as shown in FIG. 4B, the primary differentiation processing can be performed.

In this embodiment, the image processing unit 120 of the lenticular lens sheet defect inspection apparatus 100 includes
10 CCD line sensor cameras 200a, 200
b, each image data (signal) obtained by 200c is subjected to the following processing. FIG. 5 is a diagram for explaining image processing on image data (signal) obtained from one CCD line sensor camera. The second derivative in FIG. 5 performs a product-sum operation 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,
Line data obtained by a predetermined number of continuous samplings is accumulated, and a product-sum operation is performed between the line data. In the case of FIG. 5, this processing is performed between the nine line data. However, every time new line data is sampled, this processing is always performed on the nine line data except for the line data that is gradually older. ) Indicates D _ij 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 multiply-accumulated between the lines, the results of the secondary differentiation processing and the primary differentiation processing are respectively 5 (b) and FIG. 5 (c). Slice processing is performed on each of the operation results of the secondary differentiation processing and the operation results of the primary differentiation processing obtained in this manner, and a defect that exceeds a predetermined threshold is detected. Here, the line data means the image pickup means (CCD
Line sensor camera), straddling the width in the direction substantially perpendicular to the moving direction of the lenticular lens sheet,
It refers to data corresponding to the entire area of the predetermined width among the imaging data in one sampling of the visual field including the predetermined width on a straight line on the sheet surface.

Next, a second embodiment of a lenticular lens sheet defect inspection apparatus according to the present invention will be described. The lenticular lens sheet defect inspection apparatus according to the second embodiment is a defect inspection apparatus for detecting a defect (white defect) in a light-shielding film portion of a light-shielding stripe portion, which is called a black stripe 730 shown in FIG. The appearance is the same as that of the first embodiment shown in FIG. 1, but the overall schematic configuration of the defect detection function is as shown in FIG. 6, and the photographing means is provided for passing through a lenticular lens sheet. A CCD line sensor camera 610 as an imaging unit and a linear light source 620 as an illumination unit shown in FIG. Also in this embodiment, as in the first embodiment, when inspecting on a production line (in-line), the lenticular lens sheet is passed at a constant speed.
CCD line sensor camera 610 Photographs a predetermined area of the lenticular lens sheet 640 and outputs image signals (data).
, And the obtained image signal (data) is
0 to perform defect detection. The imaging means is C
Only one CD line sensor camera 610 captures the entire imaging field of view 650 on a straight line in the width direction of the sample (lenticular lens sheet) 640. The light source 620 illuminates the sample (lenticular lens sheet) 640 with respect to the CCD line sensor camera 610 by reflection and dark field illumination. The image data (signal) obtained by the CCD line sensor camera 610 is subjected to a primary differentiation process or a secondary differentiation process using a spatial filter in the same manner as in the embodiment, and the obtained result is further sliced. Those exceeding a predetermined threshold are detected as defects. In FIG. 6, two lines from the CCD line sensor camera 610 represent the field of view taken by the camera.

In the first and second embodiments, a predetermined area required for obtaining image data (signal) of a sample (lenticular lens sheet) is imaged by one CCD line sensor camera, and the image data is obtained. However, if the sample to be inspected (lenticular lens sheet) is large, the image is divided and imaged by a plurality of CCD line sensor cameras, and the image data (signal) of the required area is obtained. Is also good. Further, with the configuration in which the devices of the first embodiment and the second embodiment are combined into one, it is also possible to detect a defect inside the resin of the lenticular lens sheet and a defect of the light shielding film of the black stripe portion by one photographing device. It is.

[0013]

According to the present invention, as described above, a lenticular lens which can cope with high quality and mass production is illuminated by transmission or reflection in a dark field, and an image taken by a linear area imaging means is subjected to image processing. Provided is a compact lenticular lens defect inspection device that can be withdrawn from the production line (inline) to offline when the lenticular lens production type is changed, etc. It is possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a lenticular lens sheet defect detection apparatus according to an embodiment.

FIG. 2 is a functional configuration diagram of a defect detection device of the lenticular lens sheet according to the first embodiment;

FIG. 3 is a diagram showing a modified example of the functional configuration of the defect detection device of the lenticular lens sheet according to the first embodiment;

FIG. 4 is a diagram showing a spatial filter;

FIG. 5 is a diagram for explaining image processing in the embodiment.

FIG. 6 is a functional configuration diagram of a defect detection device of the lenticular lens sheet according to the second embodiment.

FIG. 7 is a view showing a defect of a lenticular lens sheet.

FIG. 8 is a view for explaining imaging by tilting imaging;

[Explanation of symbols]

Reference Signs List 100 Defect detection device for lenticular lens sheet 110 Imaging device 111 Lenticular lens sheet passage recess 112 Imaging device support portion 112a Fitting portion 120 Image processing portion 130 Lenticular lens sheet 140 Rail 141 Roller 200a, 200b, 200c CCD line sensor camera 210 Light source 220 Image processing unit 230 Lenticular lens sheet 240 Image field of view 300a, 300b, 300c CCD line sensor camera 310 Light source 320a, 320b, 320c Mirror 330 Image field of view 610 CCD line sensor camera 620 Light source 630 Image processing unit 640 Lenticular lens sheet 650 Image field of view 700 Lenticular lens sheet 710, 711 Lenticular lens 730 Black strike

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 21/89-21/958 G01M 11/00

Claims (2)

(57) [Claims] At least a predetermined width on a straight line on a surface of a lenticular lens sheet that crosses a width in a direction substantially perpendicular to a moving direction of the lenticular lens sheet is picked up by transmitted light or reflected dark field light. The transmitted light illumination and / or the reflected dark field illumination for imaging are supplied to the one or more linear area imaging means and the one or more linear area imaging means for imaging the lenticular lens. Illuminating means, and image processing means for detecting a defect based on image data obtained by the linear region imaging means, while moving a continuous plate-shaped lenticular lens sheet at a constant speed, while transmitting transmitted light or A defect inspection apparatus for detecting a defect of the lenticular lens sheet by using reflected dark-field light, wherein the linear region imaging unit and the illumination unit are integrated. A lenticular lens sheet defect inspection apparatus, comprising: a photographing means, and a moving means for moving the photographing means between a production line and offline. 2. The lenticular lens sheet defect inspection apparatus according to claim 1, wherein the moving means moves on a rail by a roller or the like attached to the photographing means.