JP2002277411A - Method and apparatus for inspecting transparent laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect the presence of foreign matter in a transparent laminate with good accuracy. SOLUTION: The inspection device 1 is constituted so as to inspect the transparent laminate 2 wherein a plurality of transparent materials are laminated by detecting whether foreign matter is present in the laminate. The device is equipped with an illumination means 3 for irradiating the transparent laminate 2 with light, a light detection means (4) for detecting the reflected light from the transparent laminate 2, and an arithmetic means 50 for operating image data corresponding to the quantity of light obtained by the light detection means (4). Further, the device is equipped with a foreign matter decision means 52 constituted so that the image data of the surface states of the transparent materials are operated at every transparent material by the arithmetic means, that the transparent material having possibility such that foreign matter is present is specified from the surface states of the respective transparent materials, and that the surface state of this transparent material is compared with that of at least one transparent material adjacent thereto to determine whether the foreign matter is present in the transparent laminate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for inspecting a transparent laminate such as a liquid crystal display (LCD) for the presence of foreign matter inside.

[0002]

2. Description of the Related Art As a transparent laminated body in which a plurality of transparent bodies are laminated, for example, a liquid crystal display (LCD) shown in FIG.
There are two. The LCD 2 includes, for example, a pair of transparent substrates 2
The liquid crystal 22 is sealed between the transparent substrates 1a and 21b, and the polarizing plates 23a and 23b are provided on the surfaces of the transparent substrates 21a and 21b.
Are arranged as a transmission type. In such an LCD 2, usually, at the stage of shipment from a factory, a protective sheet 24 made of resin or the like is attached to the surface of the polarizing plate 23a to protect the polarizing plate 23a. In this state,
The LCD 2 is inspected for foreign matter such as glass cullet, resin particles, fibers, and bubbles.

[0003] Inspection of foreign matter, for example, as shown in FIG.
This is performed by imaging the LCD 2 with a solid-state imaging device 4 such as a CCD camera. In this case, the solid-state imaging device 4
8A to 8D, the surface of each transparent body (for example, the protective sheet 24, the polarizing plate 23a, or the transparent substrate 21a) is taken as one image, and each transparent object is converted from each image. By grasping the surface condition of the body, it is determined whether or not a foreign substance exists in the LCD 2.

[0004]

However, LCDs
As shown in FIG. 6, the protective sheet 24 of FIG.
a, or the dirt 24b may be attached. In this case, the scratches 24a and dirt 24b are lower than the protective sheet 24 as shown in FIGS. 8 (a) to 8 (d). In the transparent body (such as the polarizing plate 23a and the transparent substrate 21a). For this reason, even if there is a foreign substance in each image, it may be due to the influence of the scratch 24a or the dirt 24b of the protective sheet 24. As a result, there is no foreign substance inside the LCD 2, and an erroneous determination occurs that the LCD 2 itself is determined to be defective even though the LCD 2 itself is good. Such a problem occurs not only in the LCD 2 but also in other transparent laminates.

The present invention has been made in view of such circumstances, and has as its object to enable accurate inspection of the presence of foreign matter in a transparent laminate.

[0006]

DISCLOSURE OF THE INVENTION The present invention employs the following technical means to solve the above-mentioned problems.

[0007] The method for inspecting a transparent laminate provided by the first aspect of the present invention is a method for inspecting whether or not a foreign substance exists inside a transparent laminate in which a plurality of transparent bodies are laminated. A first step of irradiating the transparent body with light and grasping the surface state of each transparent body from the reflection state of light on the surface of each transparent body; Or a second step of specifying a transparent body in which foreign matter may be present inside;
Comparing the surface state of the transparent body specified in the step with the surface state of at least one transparent body adjacent to the transparent body to determine whether or not there is a foreign substance in the transparent laminate; And a step of:

According to a second aspect of the present invention, there is provided an apparatus for inspecting the presence or absence of a foreign substance inside a transparent laminate in which a plurality of transparent bodies are laminated, and irradiating the transparent laminate with light. Inspection of a transparent laminate comprising: an illuminating means for receiving light; a light receiving means for receiving reflected light from the transparent laminate; and a calculating means for calculating image information according to the amount of light obtained by the light receiving means. In the apparatus, the calculating means calculates, for each of the transparent bodies, image information of a surface state of the transparent body,
In addition, from the surface state of each transparent body, a transparent body in which a foreign substance may be present is specified, and the surface state of this transparent body and the surface state of at least one transparent body adjacent to the transparent body are determined. An apparatus for inspecting a transparent laminate is provided, further comprising a foreign matter judging means for judging whether or not there is a foreign matter in the transparent laminate.

In a preferred embodiment, the surface state of each of the transparent bodies is grasped by measuring the state of light reflection from the transparent bodies as luminance, and it is determined whether or not foreign matter exists in the transparent laminate. The determination is made based on whether or not the difference in luminance between the transparent body in which a foreign substance may be present and at least one transparent body adjacent to the transparent body is larger than a threshold value.

In the case where the surface state of the transparent body is specified based on the luminance of the reflected light when the transparent laminate is irradiated with light, a part where a flaw or a foreign substance is present, or a flaw of the upper transparent body is determined. The brightness of a portion affected by the above becomes greater than other portions of the same transparent body. On the other hand, the degree of the effect of a flaw or the like of the transparent body in the upper layer on the transparent body in the lower layer than the transparent body becomes smaller as the distance of the flaw or the like from the transparent body increases.

Therefore, the surface state of the transparent body in which foreign matter may be present (the foreign body candidate transparent body) is compared with the surface state of at least one of the transparent bodies above or below the transparent body. For example, it can be determined whether the foreign substance is considered to be an effect of a scratch on the upper transparent body, or whether the luminance is increased due to the presence of the foreign substance on the surface or inside of the specified transparent body. Become like

For example, the luminance of a portion such as a flaw in a transparent body having a flaw or the like is measured in advance as to what degree of luminance is measured in the lower transparent body, and the corresponding portion (foreign substance candidate) in the foreign substance candidate transparent body is checked. The difference between the brightness of the corresponding portion and the brightness of the corresponding portion in at least one of the transparent body above and below the foreign object candidate transparent body is determined, and it is determined whether or not the value is greater than a predetermined threshold. It is possible to determine whether the luminance of the candidate foreign substance part is increased due to the presence of a foreign substance, or whether the luminance is increased due to a flaw of a transparent body in an upper layer. . As a result, for example, it is possible to avoid erroneous determination due to the influence of, for example, a flaw of the transparent body located above the foreign body candidate transparent body, and to reliably inspect whether or not foreign matter exists inside the transparent laminate.

[0013] Other advantages and features of the present invention will become more apparent from the following description of embodiments of the present invention.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to FIGS. Here, FIG. 1 is a schematic diagram showing an example of an inspection apparatus for a transparent laminate according to the present invention, and FIG. 2 is a schematic enlarged view of an essential part for explaining a method of imaging the surface state of each transparent body by the inspection apparatus of FIG. FIG. 3 is a plan view of a main part of the transparent body laminate at the time of imaging, FIG. 4 is a view showing an example of an image of the transparent body taken, and FIG.
9 is a flowchart for explaining a foreign matter determination process.

As shown in FIG. 1, an inspection apparatus 1 inspects whether or not a foreign substance exists inside a transparent laminate 2. The inspection apparatus 1 includes an illumination device 3, an imaging device 4, and an information processing device 5. It is roughly configured.

The transparent laminate 2 is formed by laminating a plurality of transparent bodies, and FIGS. 2 and 6 show a liquid crystal display (LCD) as an example of the transparent laminate 2. The LCD 2 is configured as a transmissive type, and a pair of transparent substrates 21a and 21b provided with a plurality of linear transparent electrodes 20a and 20b are used as the transparent electrodes 21a and 21b.
b are arranged so as to face each other. A liquid crystal layer 22 is provided between the pair of transparent substrates 21a and 21b and filled with liquid crystal.
The polarizers 23a and 23b are arranged on the surface opposite to the surface adjacent to the liquid crystal layer 22 in FIG. When the LCD 2 is shipped from the factory, a transparent protective sheet 24 made of resin or the like is provided on the surface of the polarizing plate 23a.

In the LCD 2, at least a pair of transparent substrates 21a and 21b, a liquid crystal layer 22, and polarizing plates 23a and 2a.
3b and the protection sheet 24 constitute the transparent body of the transparent laminate 2. In addition, the LCD 2 checks the slide table 6 when inspecting whether or not foreign matter exists inside the LCD 2.
0 is fixed via a support portion 61 and is relatively moved with respect to the illumination device 3 and the imaging device 4 in the arrow X direction in the figure.

The illuminating device 3 irradiates light so that the incident angle with respect to the transparent laminate 2 becomes θ as shown in FIG. The illuminating device 3 has, for example, a laser light source, a collimator lens, and an aspherical cylinder lens (not shown), and can irradiate the laser beam linearly over the entire length of the transparent laminate 2 in the width direction. . As described above, since the LCD 2 is relatively moved with respect to the illumination device 3 and the imaging device 4, in the inspection of the LCD 2, the laser light from the illumination device 3 is caused to scan the LCD 2 in the X direction (see FIG. 1). It will be. This laser beam has, for example, a wavelength of 635 nm and a line width of 30 μm.

When the illumination device 3 irradiates the LCD 2 with linear laser light, most of the laser light
D2, but a part of each of the transparent bodies (protective sheet 2)
4 and the surface (interface) of the polarizing plate 23a).
Therefore, when the illumination device 3 irradiates the LCD 2 with linear laser light in a plan view, a plurality of bright lines A, B, C, D, and E are confirmed as shown in FIG.

The image pickup device 4 has a solid-state image pickup device 40 and a condenser lens 41 as shown in FIG.

Although not shown in the drawing, the solid-state image pickup device 40 has a plurality of light-receiving elements arranged in a row extending in the width direction of the LCD 2 (direction intersecting with the arrow X direction in FIG. 1). I have. Of course, a plurality of such rows may be provided, and the plurality of light receiving elements may be arranged in a matrix. Each light receiving element outputs an electric charge of an amount corresponding to the amount of reflected light from the LCD 2. As a result of arranging the plurality of light receiving elements in a row, reflected light appearing as bright lines A to E becomes a plurality. Is output as line data composed of dot data of.

On the other hand, the condenser lens 41 is configured to be capable of individually condensing light on each light receiving element. The condenser lens 41 can be reciprocated in the optical axis direction by, for example, an actuator 42. By moving the condenser lens 41, any one of the plurality of bright lines A to E can be focused. Therefore, the solid-state imaging device 4
Can mainly receive the reflected light from the surface of each transparent body. As a result, the solid-state imaging device 4
Line data in a reflection state corresponding to the illumination line in the CD 2 can be output for each transparent body. Of course, focusing on each of the bright lines A to E may be achieved by another configuration.

The information processing device 5 includes, for example, a CPU, RA
M and a ROM, etc., and have functions as a control unit 50, a calculation unit 51, and a foreign matter determination unit 52 as shown in FIG.

The control means 50 controls the lighting device 3 (see FIG. 1).
, The movement of the slide table 60 (see FIG. 1), the movement of the condenser lens 41 (see FIG. 2) of the solid-state imaging device 4, and the like.

The calculating means 51 outputs the respective transparent bodies (the protection sheet 24 and the polarizing plate 23) based on the output from the solid-state image sensor 40.
a (see FIG. 2)) to calculate data necessary to represent the surface state. More specifically, in accordance with the output from the solid-state imaging device 40, the brightness of the dots constituting each line is calculated for each transparent body, and the calculated brightness is integrated.
As shown in (a) to (c), dot map data (image information) expressed based on luminance is calculated for each transparent body.

In FIGS. 4A to 4C, for the sake of simplicity of explanation, one 8 × 8 dot map is used for each transparent body.
The result of calculating data as one image is shown.
Also, in FIGS. 4A to 4C, four types of dots of black, cross hatching, single hatching, and white are drawn, but these dot expressions are convenient for expressing in the drawings. This is a method, and as an actual image, for example, the magnitude of the luminance is expressed as a shade. Further, FIG.
In FIG. 4, the luminance is displayed such that the luminance increases in the order of black> cross hatching> single hatching> white, and the dot corresponding to a portion where a flaw or a foreign substance exists has a higher luminance. 3) to (c) show dots (foreign matter candidate dots) whose luminance is higher than that of the white dots due to the possibility of foreign matter other than white dots.

The foreign matter determining means 52 specifies a transparent body (foreign matter candidate transparent body) in which a foreign matter may exist, and determines whether or not a foreign matter actually exists in this transparent body. is there. The specific foreign matter determination processing method will be described with reference to the flowchart of FIG. 5 and also to FIG. 1 and FIG.

The foreign matter determining means 52 first determines whether or not there is a transparent body (foreign matter candidate transparent body) in which foreign matter may exist in the transparent body of the LCD 2 (S1). When a foreign substance is present in each transparent body, the luminance in that part increases. Therefore, the foreign substance determining unit 52 determines whether there is a foreign substance candidate dot having a luminance of 250 cd / m ² or more for each transparent body. The presence or absence of the foreign object candidate transparent body is determined based on whether or not there is no foreign object candidate.

If the foreign matter determining means 52 determines that there is a foreign matter candidate dot on any of the transparent bodies (S1: YE
S), a transparent body having such dots is specified as a foreign substance candidate transparent body (S2). In the LCD 2 to which the protection sheet 24 is attached, the protection sheet 24 is LC
It cannot be a factor for determining whether D2 is a good product or a defective product. Therefore, even if dots having a luminance of, for example, 250 cd / m ² or more exist on the protection sheet 24, the protection sheet 24 is not specified as a foreign substance candidate transparent body. In the following description, S2
In the transparent substrate 2 as one of the foreign substance candidate transparent bodies
It is assumed that 1a is specified.

Next, the foreign matter determining means 52 specifies a foreign matter candidate transparent body, for example, a foreign matter candidate dot on the transparent substrate 21a (S3). In the present embodiment, as shown in FIG. 4B, (I, J)
_21a = (2,2) _21a , (2,4) _21a , (3,6) _21a ,
(5,2-4) _21a , (6,2-4) _21a , (75,1-
4) It is assumed that 13 dots _21a are specified as foreign object candidate dots.

Subsequently, the foreign matter judging means 52 outputs one foreign matter
Candidate dot (for example, (2,2)_{twenty one a}), 1
Foreign matter candidate dots on the polarizing plate 23a, which is the upper layer,
Corresponding dot (2,2)_23aCalculate the difference between the brightness of
That is 0 cd / m^TwoIt is determined whether it is greater than (S
4). Difference is 0 cd / m^TwoDetermine if it is greater than
The reason is that the brightness is affected by the influence of scratches on the protection sheet 24 and the like.
Foreign matter candidate dot (2, 2) growing_21aThen
The corresponding upper dot (2, 2)_23aCompared to
Because the brightness is lower or about the same.
You.

In S4, when the foreign matter judging means 52 judges that the difference is smaller than 0 cd / m ² (S4:
NO), the said foreign object candidate dots (2, 2) _21a, it is determined that the brightness is increased due to the influence of scratches in the protective sheet 24, the foreign object candidate dots (2, 2) _21a of the transparent substrate 21a It is determined that no foreign matter exists in the corresponding portion (S5).

On the other hand, in S4, the difference is 0 cd / m ²
If the foreign matter determination means 52 determines that the size is larger than the threshold value (S4: YES), the foreign matter determination means 52 determines the foreign matter candidate in one lower liquid crystal layer 22 from the luminance of the foreign matter candidate dot (2, 2) _21a. Dot (2,
2) The difference between the luminances of ₂₂ is calculated, and it is determined whether or not the difference is greater than 50 cd / m ² (S6).

The determination as to whether the difference is greater than 50 cd / m ² is based on the following reason. When a foreign substance is present on the transparent substrate 21a, the dot (2, 2) corresponding to the foreign substance candidate dot (2, 2) _21a on the liquid crystal layer 22 is displayed.
2) The luminance of ₂₂ may be affected, but the degree of the influence is smaller than that of the case of the scratch. In other words, there is a difference in the degree of attenuation of luminance in the lower transparent body between the influence of the presence of foreign matter and the influence of the presence of scratches. Therefore, as a result of examining the threshold value for distinguishing the LCD 2 from the LCD ^2, a value of 50 cd / m ² is obtained as one of the threshold values. Therefore, when the transparent laminate 2 is
Otherwise, or even if the transparent laminate 2 is an LCD, if the composition, thickness, etc. of each transparent body are different, the threshold value is determined accordingly.

In S6, when the foreign matter judging means 52 judges that the difference is smaller than 50 cd / m ² (S6).
6: NO), it is determined that the luminance of the foreign substance candidate dot (2, 2) _21a is increased due to the influence of a scratch or the like on the protective sheet 24, and corresponds to the foreign substance candidate dot on the transparent substrate 21a. It is determined that no foreign matter exists in the portion (S5).

On the other hand, in S6, the difference is 50 cd / m
^{If the} foreign matter judging means 52 judges that it is larger than ² (S6: YES), the foreign matter judging means 52
It is determined that a foreign object exists in a portion corresponding to the foreign object candidate dot (2, 2) _21a in (a) (S7).

Next, the foreign matter judging means 52
For all the foreign object candidate dots specified in 1a,
It is determined whether it has been determined whether or not the cause of the increase in luminance is due to the presence of a foreign substance (S
8). In S8, when the foreign matter determination unit 52 determines that there is any foreign matter candidate dot specified on the transparent substrate 21a for which foreign matter determination has not been performed (S8: N
O) S4 to S7 are repeated for the other foreign matter candidate dots for which no determination has been made, and after foreign matter determination has been performed for the foreign matter candidate dots, the determination of S8 is made. In the present embodiment, as shown in FIG. 5B, 13 foreign object candidate dots (2, 2) _21a , (2, 4) _21a , (3, 6)
_21a , (5, 2-4) _21a , (6.2-4) _21a , (7
5, 5, 4) Since _21a has been confirmed, in this case, the processing of S3 to S7 is performed 13 times.

On the other hand, when the foreign matter determination means 52 determines that foreign matter determination has been performed on all the foreign matter candidate dots specified on the transparent substrate 21a (S8: YES), the foreign matter candidate transparent body specified is It is determined whether or not a foreign object has been determined (S9).

In S9, if the foreign matter determination means 52 determines that there is a foreign matter candidate transparent body for which foreign matter determination has not been performed among the specified foreign matter candidate transparent bodies (S9: NO),
For other foreign object candidate transparent bodies for which foreign object judgment has not been performed,
The processing of S3 to S8 is repeatedly performed.

On the other hand, the foreign matter determination means 5 determines that foreign matter has been determined for all the foreign matter candidate transparent bodies specified in S9.
If it is determined that No. 2 is determined (S9: YES), and if it is determined in S1 that there is no transparent body in which a foreign substance may be present (S1: NO), the foreign substance determination processing ends.

In such a foreign matter judgment process, after the foreign matter candidate transparent body is specified, the surface state of the transparent body one layer above and one layer below the foreign matter candidate transparent body is compared with the foreign matter candidate dots. By comparing the brightnesses of the above, it is determined whether or not the reason why the brightness of the foreign object candidate dot is high is due to the presence of the foreign object. Therefore, when the luminance is increased due to the influence of a scratch or the like of the transparent body (for example, the protective sheet 24) in the upper layer,
It is determined that the reason why the brightness of the dot is high is not due to foreign matter. As a result, the presence of foreign matter in the transparent laminate can be accurately inspected.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a transparent laminate inspection apparatus according to the present invention.

FIG. 2 is a schematic enlarged view of a main part for describing a method of imaging the surface state of each transparent body by the inspection device of FIG. 1;

FIG. 3 is a plan view of a main part of the transparent laminate at the time of imaging.

FIG. 4 is a diagram illustrating an example of an image of a transparent body.

FIG. 5 is a flowchart illustrating a foreign matter determination process. It is a schematic diagram which shows an example of the inspection apparatus of the transparent laminated body which concerns on this invention.

FIG. 6 is a perspective view of an essential part showing a liquid crystal display device which is an example of a transparent laminate.

FIG. 7 is a schematic diagram of an inspection apparatus referred to for describing a conventional method for inspecting a transparent laminate.

FIG. 8 is a diagram illustrating an example of an image of each transparent body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspection apparatus 2 LCD (transparent laminated body) 3 Illumination device 4 Imaging device 40 Solid-state imaging device 51 Computing means 52 Foreign substance determination means

Claims (3)

[Claims] 1. A method for inspecting whether a foreign substance is present inside a transparent laminated body in which a plurality of transparent bodies are laminated, wherein the transparent body is irradiated with light and the surface of each of the transparent bodies is inspected. A first step of ascertaining the surface state of each of the transparent bodies from the light reflection state at the time of; and identifying a transparent body that may have a foreign substance on its surface or inside from the surface state of each of the transparent bodies. Step 2; comparing the surface state of the transparent body specified in the second step with the surface state of at least one transparent body adjacent to the transparent body; And a third step of determining whether or not the transparent laminate is inspected. 2. The surface state of each transparent body is grasped by measuring the light reflection state of the transparent body as luminance, and whether or not foreign matter is present in the transparent laminate is determined by the presence of foreign matter. The method for inspecting a transparent laminate according to claim 1, wherein the difference between the luminance of the transparent body having a property and at least one transparent body adjacent to the transparent body is determined based on whether or not the difference is larger than a threshold value. 3. An apparatus for inspecting whether a foreign substance is present inside a transparent laminate in which a plurality of transparent bodies are laminated,
Illuminating means for irradiating the transparent laminate with light, light receiving means for receiving light reflected from the transparent laminate, and arithmetic means for calculating image information according to the amount of light obtained by the light receiving means, In the inspection apparatus for a transparent laminate provided with the above, the calculation means calculates image information of the surface state of the transparent body for each of the transparent bodies, and a foreign substance is present from the surface state of the transparent body. A possible transparent body is specified, and a surface state of the transparent body is compared with a surface state of at least one transparent body adjacent to the transparent body to determine whether a foreign substance is present in the transparent laminate. An inspection apparatus for a transparent laminate, further comprising: a foreign matter determination unit for determining whether or not there is a foreign matter.