JPH06288927A - Image process inspection method - Google Patents

Abstract

PURPOSE:To obtain an inspection range by moving an object to be inspected while emitting a light to a plate which places the object; and imaging a transmitted light or a reflected light of the object to be inspected by an electronic imaging unit. CONSTITUTION:A polarization film 3 is placed on a black surface plate 1, the plate 1 is moved while emitting a light to the plate 1, and a reflected light of the emitted light is imaged by an electronic imaging unit 4 with a polarizing plate to obtain a boundary point on the plate 1 in which illuminance is varied. This operation is repeated several times to set a regression rectilinear line of a point sequence as a boundary line, and the boundary line is stored in a computer 6. A range surrounded by the boundary line is set as an inspection range, and a malfunction position of the inspection range is inspected by an inspection apparatus moving by a command of the computer 6. Thus, the inspecting range is obtained, and the malfunction position of the inspecting range is detected all by the computer 6, and hence it can be rapidly and accurately conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing inspection method for an inspection object such as a film. In particular, the present invention relates to an image processing inspection method suitable for inspecting an object to be inspected, such as a polarizing film used for a liquid crystal display plate, by processing an image captured by an electronic imaging device.

[0002]

2. Description of the Related Art Conventionally, a polarizing film used for a liquid crystal display panel or the like is one in which an adhesive is applied on a polarizing film substrate, but air bubbles, dust and the like are mixed in this polarizing film. There are cases. In particular, air bubbles, dust, and the like are often mixed in the adhesive layer of this polarizing film. When the polarizing film is used as a liquid crystal display panel or the like, the presence of a large number of air bubbles, dusts and the like in the polarizing film will hinder the display characteristics.

Therefore, after manufacturing the polarizing film, a part of the film is extracted from the lot and inspected for bubbles and dust. This inspection is performed by sticking a film cut to a size actually used on a glass plate. However, in order to automatically perform such an inspection using a computer, it is necessary to determine the position of the polarizing film during the inspection and store it in the computer. As a method of determining the position of the polarizing film, there is a method of measuring and determining the inclination of the inspection object such as the polarizing film. As a method for measuring the inclination of such an object to be inspected, there is known a method of utilizing a moment of inertia as described in JP-A-4-195596.

[0004]

However, with this method of utilizing the moment of inertia, the range can be determined when the object to be inspected is relatively small so that it is completely included in the visual field, but it is used for liquid crystal display panels and the like. Since the polarizing film used is usually large, it cannot be included in the field of view, and therefore the moment of inertia cannot be utilized.

It is conceivable to reduce the magnification of the lens so that the polarizing film is included in the visual field, but there is a limit to the range that can be covered by one lens. Further, even if a lens included in the visual field is selected, if the surface is inspected with the same lens after the inspection range is determined, sufficient resolution cannot be obtained. For example, the stereo microscope has a zoom ratio of about 6.3 ×, but if a resolution of 10 μm is to be obtained, even if a zoom lens with a large zoom ratio is used, the field width of this zoom lens is at most 32 mm. Yes (when sampling at 512 points per line). Therefore, when a large field of view is required, a mechanism such as exchanging the lens in the dust-free chamber is required, which increases the cost.

Therefore, an object of the present invention is to obtain an inspection range of an object to be inspected such as a polarizing film placed on a plate by using a computer, and to inspect a defective portion in the inspection range by a simple image processing inspection method. To provide.

[0007]

The present invention has been made to solve the above problems and achieve the above objects.
According to the invention of claim 1, an object to be inspected such as a film is placed on a plate, and at least one of the plate on which the object to be inspected is placed while irradiating light on the plate and the electronic photographing device are instructed by a computer. By moving the image, the reflected light or the transmitted light of the irradiated light is photographed by an electronic photographing device, and the operation of obtaining the boundary point of the object to be inspected on the plate where the density changes is performed twice or more at different places, Set the regression line of the sequence of points as a boundary line, calculate the required number of positions of the boundary line according to the shape, store this position in the computer, and set the range enclosed by this boundary line as the inspection range, and instruct the computer By moving either the plate on which the object to be inspected is placed or the electronic imaging device, the defective portion in the inspection range is inspected.

According to a second aspect of the present invention, an object to be inspected such as a film is placed on a black surface plate, and the black surface plate on which the object to be inspected is moved while irradiating the plate with light. ,
The reflected light of this irradiated light is photographed with an electronic photographing device,
Perform the operation to find the boundary point of the object to be inspected on the plate whose density changes, at two or more different places, set the regression line of the point sequence as the boundary line, and set the position of the boundary line to the required number according to the shape. This position is obtained and stored in the computer, the range surrounded by the boundary line is set as the inspection range, and the black plate on the surface is moved according to the instruction of the computer to inspect the defective part in this inspection range. .

In the above inspection method, the boundary points at which the density changes are the average density of the adjacent blocks of the average density in the block obtained by dividing a part of the image obtained by imaging into fine strips. It refers to the block with the maximum difference value from the density. Here, the electronic photographing device is a device such as a television camera or a video camera which can directly output an image to a television or a computer, or can be stored in a storage medium such as a magnetic tape. Is not developed on paper.

In the present invention, since the film or the like of the object to be inspected placed on the plate may move, a glass plate may be placed on the object to be inspected such as a film on the plate or the glass plate. The object to be inspected such as a film may be attached to the plate with an adhesive and then placed on a plate. In the present invention, since it is easier to photograph the reflected light than to photograph the transmitted light of the inspected object such as the film, it is usually sufficient to photograph the reflected light of the inspected object such as the film. Also, when photographing this reflected light, if the surface of the plate on which the object to be inspected is made black, or if it is covered with a black cloth and placed on a black surface plate, it will depend on the object to be inspected. This is preferable because the difference in light density becomes large. or,
In the present invention, at least one of the plate on which the inspection object is placed and the electronic imaging device is moved, but it is preferable to move the plate on which the inspection object is placed because it is easier to operate.

[0011]

The operation of the image processing inspection method of the present invention will be described.
First, an object to be inspected such as a polarizing film is placed on the plate. At this time, it is convenient to place a glass plate on the object to be inspected or to bond the object to be inspected to the glass plate because it does not move during the inspection. When the reflected light is photographed, it is preferable that the surface of the plate be black by placing a black cloth on the surface of the plate. Next, when photographing reflected light, a light irradiation device and an electronic photographing device are attached above the object to be inspected.
When photographing transmitted light, an irradiation device and an electronic photographing device are attached to both sides of the plate.

Next, while irradiating the plate with light, the plate or the electronic photographing device is moved in a fixed direction, for example, linearly, according to an instruction from the computer. Then, when photographing a small portion of only the plate, the density in the screen is generally the same. After that, when the small part being imaged moves to take an image of the small part of the object to be inspected placed on the plate, the imaging device includes the part where the object to be inspected and the part of the plate only. The amount of light that reaches is different.

Further, when it is moved to a place where the object to be inspected disappears, the image of only the plate is taken again. Therefore, the boundary of the object to be inspected on the plate can be known by measuring the change in the density, and this position is stored in the computer. Since a large number of boundary points are found by performing such an operation a plurality of times at different places, the boundary line is defined by connecting these boundary points, and the place where the object to be inspected is found by enclosing it with this, This place is the inspection range.

If the number of boundary points is increased by performing this operation a lot, the range of the object to be inspected becomes more accurate,
When performing the operation two or more times, if the first movement of the plate is made linear and the next movement is made to move on a line substantially parallel to this straight line or a line orthogonal to this straight line, the boundary of the object to be inspected is regular. It is convenient because it turns out. Next, a defective portion inside the inspection range is obtained by the inspection device that moves according to the instruction of the computer, and this position is stored in the computer.

As described above, since the inspection range and the position of the defective portion can be stored in the computer, the inspection can be automatically performed. In such a method, no matter how large the object to be inspected such as a polarizing film, as long as the object to be inspected such as the light source or the polarizing film can be moved, the position of the object to be inspected and the position of the defective portion in the object to be inspected Can be determined.

[0016]

EXAMPLES Next, examples of the present invention will be described. 1 to 6
Shows an embodiment of the image processing inspection method of the present invention by taking the inspection method of a polarizing film as an example. FIG. 1 is an explanatory view showing a state in which the polarizing film is inspected, and FIG. 2 shows the plate of FIG. FIG. 2 is a front view showing a state in which a polarizing film is placed on top of FIG.
4 is an explanatory view showing an enlarged boundary portion between the plate and the polarizing film, FIG. 4 is an explanatory view showing a state in which the boundary portion in FIG. 3 is being measured, and FIG. 5 is an image of the portion in FIG. 3 taken by an electronic photographing device. Then, an explanatory view showing the relationship between the block position and the average density, and FIG. 6 is an explanatory view showing the measured inspection range.

1 to 6, reference numeral 1 denotes a black plate having a black surface. Reference numeral 3 is an inspected body made of a polarizing film, and the inspected body 3 is attached to the glass plate 2 by an adhesive by hand. Therefore, the inspection object 3 is not always attached to the glass plate 2 at an accurate position. Then, the device under test 3 is placed on the plate 1 with the device under test 3 facing downward.

Reference numeral 4 denotes an electronic photographing apparatus, which is a stereoscopic microscope 41 having a zoom lens 42 and a television camera 4 mounted behind the stereoscopic microscope 41.
The image captured by the stereomicroscope 41 can be directly input to the central processing unit 6 including a computer. The central processing unit 6 includes an A / D converter,
It is composed of an image memory section and the like so that the boundary of the polarizing film 3 can be measured. Reference numeral 5 denotes an illuminating device which is annularly provided around the zoom lens 42 so as to illuminate in the same direction.

Next, a method of inspecting the polarizing film 3 will be described. The inspected body 3 made of a polarizing film was adhered to the glass plate 2 by hand using an adhesive. Therefore, the position of the device under test 3 on the glass plate 2 is not accurate. Next, the glass plate 2 to which the inspection object 3 is bonded is placed on the black plate 1 of the surface of the inspection device with the inspection object 3 facing downward.

Next, the illuminating device 5 irradiates the edge of the glass plate 2. Next, the black surface plate 2 is placed at a predetermined position, for example,
Moving on a straight line, the electronic photographing device 4 photographs the portion on the glass plate 2, and in this image, a part is divided into fine strip-shaped blocks as shown in FIG. The density is obtained, and the computer in the central processing unit 6 stores the relationship between the block position and the average density. For example,
It moves on the line of X1, X2, X3, Y1, and Y2 shown in FIG. At this time, the block size may be appropriate. For example, 50 pixels horizontally and 10 pixels vertically.

As a result, as shown in FIG. 5, since only the plate 1 is in the uppermost block, the light transmitted through the glass is reflected by the black surface, so that the average density of this block a ₁ is low. . The same applies to blocks a ₂ and a ₃ . Then, the block a at the boundary between the polarizing film 3 and the glass plate 2
_{At n} , it becomes a little bright because a part is reflected by the polarizing plate.
Furthermore, in the next block, it is bright because it is all reflected by the polarizing plate. This state is illustrated in FIG. 5, and the changing position A is obtained. The changing position B is obtained by searching for a block position that becomes dark on the line X1 from a block that becomes bright.

Similarly, X which is a place different from the line of X1
The positions C, D, E, and F at which the density changes on the lines X2 and X3 substantially parallel to 1 are obtained one after another and shown in FIG.
You get a diagram like this, connect A, C, D, B, D,
When E is connected, the space between them becomes the place where the polarizing film exists. Similarly, when the position where the illuminance changes on the Y1 and Y2 lines orthogonal to this X1 is obtained, the boundary in the Y direction is found. All these positions are stored in the computer in the central processing unit 6 so that the position of the polarizing film 3 can be determined. After that, the location of the polarizing film 3 is set as the inspection range, and the defective portion therein is measured by the same device, and this position is determined. In this way, since the inspection range can be determined, the defective portion can also be determined.

[0023]

According to the image processing inspection method of the present invention, the transmitted light or the reflected light of the object to be inspected is electronically photographed by moving the plate on which the object to be inspected such as a polarizing film is placed while irradiating the light. It is possible to obtain the boundary points of the polarizing film whose density changes by taking a picture with the device and set a regression line as a boundary line from a plurality of boundary point sequences. Therefore, by obtaining a required number of boundaries, for example, four inspected objects having a rectangular shape, the range in which the inspected object exists, that is, the inspection range can be obtained.

Since the measurement result of the inspection range is directly input to the computer from the electronic photographing device, the inspection range can be determined quickly and accurately. Then, similarly, the position of the defective portion in this inspection range can be determined by the computer. This operation is a valuable invention because it can be automatically inspected for manufacturing because all the operations are performed by computer instructions.

Further, the density of light is measured by the reflected light from the surface of the object to be inspected, or the plate on which the object to be inspected is placed. When moved,
It is convenient because the operation is simple. At that time, if the surface of the plate is black, it is convenient because the lightness and darkness are more distinct and the measurement is easier. Further, it is convenient to use the difference value of the average densities of the adjacent blocks because the inspection range can be easily found by the computer.

[Brief description of drawings]

FIG. 1 shows an embodiment of the image processing inspection method of the present invention, and is an explanatory view showing a state of inspecting a polarizing film.

FIG. 2 is a front view showing a state in which a polarizing film is placed on the plate shown in FIG.

FIG. 3 is an explanatory view showing a boundary portion between the plate and the polarizing film in FIG. 2 in an enlarged manner.

FIG. 4 is an explanatory diagram showing a state where the boundary portion of FIG. 3 is being measured.

FIG. 5 is a diagram of a portion of FIG. 3 photographed by an electronic photographing device;
It is explanatory drawing which shows the relationship between a block position and average density.

FIG. 6 is an explanatory diagram illustrating a measured inspection range.

[Explanation of symbols]

1 black plate on the surface 2 glass plate 3 object to be inspected (polarizing film) 4 electronic imaging device 41 stereoscopic microscope 42 zoom lens 44 television camera 5 lighting device 6 central processing unit (including computer)

Claims (3)

[Claims] 1. An object to be inspected such as a film is placed on a plate, and at least one of the plate on which the object to be inspected and the electronic photographing device is moved under the instruction of a computer while irradiating the plate with light. Then, the reflected light or transmitted light of the irradiated light is photographed by an electronic photographing device, and the operation for obtaining the boundary point of the object to be inspected on the plate where the density changes is performed twice or more at different points. The regression line of the column is set as the boundary line, the required number of positions of the boundary line is calculated according to the shape, this position is stored in the computer, and the range surrounded by this boundary line is set as the inspection range. An image processing inspection method characterized by inspecting a defective portion in an inspection range by moving either a plate on which an inspection object is placed or an electronic imaging device. 2. An inspected object such as a film is placed on a black surface plate, and the black surface plate on which the inspected object is placed is moved while irradiating the plate with light, and the irradiated light is reflected. The operation of obtaining the boundary point of the object to be inspected on the plate whose density changes by photographing the light with the electronic photographing device is performed twice or more at different places, and the regression line of the point sequence is set as the boundary line, Calculate the required number of positions of the boundary line according to the shape, store this position in the computer, set the range surrounded by this boundary line as the inspection range, and move the black plate on the surface according to the instructions of the computer. An image processing inspection method, characterized by inspecting a defective portion in the. 3. A boundary point at which the density changes is a difference value between an average density in a block obtained by dividing a part of an image obtained by imaging into fine strips and an average density of an adjacent block. The image processing inspection method according to claim 1 or 2, wherein the block is the maximum.