JP3776628B2 - Inspection method using image processing apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an inspection method using an image processing apparatus, and more particularly to an inspection method suitable for inspecting a wiring of a transparent electrode of a liquid crystal display element.
[0002]
[Prior art]
First, a standard structure of a liquid crystal display element including a transparent substrate on which a transparent electrode wiring is formed as an example of an inspection object in the above-described inspection method will be described with reference to FIG.
[0003]
In FIG. 3, the liquid crystal display element 1 has two transparent substrates 2A and 2B made of a material such as glass and arranged substantially in parallel with a gap between the two transparent substrates 2A and 2B. The outer periphery of is sealed with a seal member 3. Among these, a transparent segment electrode 4A made of ITO or the like is disposed in close contact with the lower surface of one transparent substrate 2A located above, and the transparent segment 2A is disposed on the lower surface of the transparent substrate 2A. An alignment film 5A, which will be described later, made of polyimide is disposed so as to surround the electrode 4A. Further, a polarizing plate 6A for visually recognizing light polarized by the liquid crystal is disposed on the upper surface of the transparent substrate 2A.
[0004]
On the other hand, a transparent common electrode 4B made of ITO or the like is disposed on the upper surface of the transparent substrate 2B located below, and is applied between the electrodes 4A and 4B above the transparent common electrode 4B. An alignment film 5B made of polyimide or the like that controls the alignment of liquid crystal molecules according to the voltage is provided. Further, a polarizing plate 6B for visually recognizing light polarized by the liquid crystal is disposed on the lower surface of the glass substrate 2B.
[0005]
Then, a liquid crystal 7 is enclosed in a sealed space surrounded by the transparent substrates 2A and 2B and the seal member 3, and furthermore, in order to keep the distance between the transparent substrates 2A and 2B accurately and constant, A plurality of spherical or columnar spacers 8 are interposed between the alignment films 5A and 5B.
[0006]
Information is displayed by changing the alignment state of the liquid crystal molecules constituting the liquid crystal 7 by applying a voltage to the transparent electrodes 4A and 4B.
[0007]
By the way, the width of the routing wiring for supplying power to the transparent electrodes 4A and 4B is formed to be about 20 to 30 μm in a narrow area, and the distance between the routing wirings is set to about 10 μm in the narrow area. For this reason, in this type of liquid crystal display element, disconnection of the routing wiring and a short circuit between the routing wirings are likely to occur, and this has been a factor in lowering the yield.
[0008]
Therefore, inspection of the routing wiring that detects the disconnection of the routing wiring and the electrical short circuit at an early stage and feeds back the transparent electrode forming process has been regarded as important.
[0009]
There is an electrical inspection method as one of the above-described inspection of the routing wiring. This requires that the routing wiring to be inspected is electrically connected, and it is difficult to detect the disconnected wiring. It was.
[0010]
Further, it is known that the inspection by the image processing has different appearances of the inspection object depending on the illumination method. This illumination method can be broadly divided into transmitted illumination and reflected illumination. Transmitted illumination is a method of illuminating light from the back of the subject (inspected object) and viewing the silhouette. Reflected illumination is applied to the subject (inspected object). It is a method of observing the reflected light by applying light.
[0011]
Due to the above-described features, transmitted illumination is not used for highly translucent subjects in which silhouettes are difficult to form, and illumination devised by reflected illumination is used for inspection of transparent electrodes. For example, a method of making the transparent electrode easier to visually recognize by irradiating light from a light source to the transparent electrode through a colored filter such as blue has been studied.
[0012]
[Problems to be solved by the invention]
However, even with the use of reflected illumination using a colored filter such as blue, a thin film transparent film with a thickness of 3 to 10 nm cannot obtain a sufficient contrast for image processing, so the inspection accuracy is poor. there were. Further, in order to increase the inspection accuracy, the same inspection object must be repeatedly inspected, so that the inspection time becomes long and it is used only for limited applications such as sampling inspection.
[0013]
The present invention overcomes such problems in the conventional method, and even a test object made of a transparent material can obtain a sufficient contrast for image processing so that a high-precision inspection can be obtained in a short time. It is an object of the present invention to provide an inspection method using an image processing apparatus that can perform the above.
[0014]
[Means for Solving the Problems]
In order to achieve the above-described object, the inspection method of the present invention according to claim 1 is characterized in that the inspection object is light-transmitting and that a reflecting mirror is disposed on the back of the inspection object. In other words, a composite image of a transmission image in which the reflected light by the light is again transmitted through the inspection object and a reflection image directly reflected by the surface of the inspection object is taken into the camera. And by adopting such a configuration, the light from the light source floats up the outer peripheral edge of the inspection object on the transparent inspection object, and the light passing through the inspection object is reflected by the reflecting mirror and again inspected. Since the outer peripheral edge of the inspection object is further lifted when passing through the object, the camera can satisfactorily capture the outer peripheral edge of the inspection object on the transparent inspection object. Here, the light source includes one that emits light from a light source through a light guide such as an optical fiber.
[0015]
The inspection method of the present invention according to claim 2 is characterized in that the object to be inspected is a transparent substrate on which transparent electrode wiring is formed. Further, by adopting such a configuration, it is possible to accurately inspect the outer peripheral edge well even for a fine inspection object such as a wiring of a transparent electrode of a liquid crystal display element.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 and FIG. 2 show an embodiment of an inspection method according to the present invention. In this embodiment, a ring light (not shown) disposed in a ring light guide 10 having a cylindrical shape is used as a light source. Yes. This ring light guides light from a halogen lamp which is a light emission source (not shown) through an optical fiber, and has a light emitting surface in a ring shape. In the present embodiment, the transparent substrate 2 of the liquid crystal display element on which the lead-out wiring 9 for the transparent electrode 4 is formed is the inspection object.
[0017]
As shown in FIG. 1, a cylindrical macro lens 12 extending vertically downward is suspended from a lower wall of a CCD camera 11 that captures an image for inspection, and an outer peripheral wall of the macro lens 12. A ring light guide 10 that houses the ring light is supported. The ring light housed in the ring light guide 10 emits light downward. Further, the types of lamps of the light source are not particularly limited, and examples thereof include halogen lamps, tungsten lamps, metal halide lamps, and xenon lamps. Furthermore, the light emitting surface of the light source may be a dot or a line, but a ring light that can irradiate the object to be inspected from all angles and hardly causes a shadow of the object to be inspected is preferable.
[0018]
Below the transparent substrate 2, a reflecting mirror 13, which is a flat mirror for reflecting the light from the ring light transmitted through the transparent substrate 2 and irradiating the transparent substrate 2 again, is supported on the substrate 14. Has been. The reflecting mirror 13 may be a convex mirror or a concave mirror in addition to a plane mirror.
[0019]
Connected to the CCD camera 11 is an image processing device 15 for binarizing and analyzing the image captured by the CCD camera 11 via the macro lens 12.
[0020]
As shown in FIG. 2, the transparent substrate 2 is supported on the reflecting mirror 14 in parallel by a support tool (not shown), and the transparent substrate 2 is irradiated with light from a ring light (not shown) supported by the ring light guide 10. To emit.
[0021]
Then, the light from the ring light is directed so as to irradiate the lead wiring 9 which is an inspection object on the inspection object directly under the CCD camera 11 and passes through the transparent substrate 2. At this time, the reflection of light at the outer peripheral edge of the routing wiring 9 formed on the transparent substrate 2 is strengthened. The light that has passed through the transparent substrate 2 is reflected by the reflecting mirror 13 and passes through the transparent substrate 2 again. When the reflected light passes through the transparent substrate 2, the outer peripheral edge of the routing wiring 9 is routed. The reflection of light at is further enhanced. On the other hand, when the reflected light passes through the transparent substrate 2, the visibility of the routing wiring 9 itself is conversely lowered.
[0022]
Then, after the light reflected by the reflecting mirror 13 passes through the transparent substrate 2, the transmission image of the CCD camera 11 is a composite image of the reflected image directly reflected by the surface of the transparent substrate 2 on which the routing wiring 9 is formed. The image is taken in from the macro lens 12, input to the image processing device 15, and binarized to be analyzed. That is, after the binarization processing, the outer peripheral edge of the routing wiring 9 is subjected to expansion processing, the outer peripheral edge is recognized as the routing wiring 9, the number of the routing lines 9 is counted, and if the number exceeds the reference, the disconnection, If less, it is judged as an electrical short circuit. The image processing apparatus 15 also detects the length of each routing wire 9. If the length of the routing wire 9 is long, it is determined as an electrical short circuit, and if it is short, it is determined as a disconnection.
[0023]
In this way, by using the two elements of the number and the length of the routing wirings in combination, the electrical short circuit and the disconnection of the routing wiring 9 can be detected with an accuracy of almost 98%. Further, since the number and length are detected by binarization processing in the image processing device 15, it is possible to measure in a short time and the inspection time is greatly shortened.
[0024]
According to the inspection method of the present embodiment described above, only the outer peripheral edge of the routing wiring 9 connected to the transparent electrode 4 can be lifted, and the visibility of the routing wiring 9 itself can be lowered, so that the contrast is enhanced. Thus, good inspection accuracy can be obtained in a short time.
[0025]
In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed. For example, in the embodiment described above, oblique illumination using a ring light is used, but a reflecting mirror may be added to coaxial incident illumination using a point light source such as a halogen lamp and a half mirror. Further, the inspection method of the present invention is not limited to the above-described inspection of the lead wiring in the transparent electrode of the liquid crystal display element, and can be applied to the inspection of various translucent members.
[0026]
【The invention's effect】
As described above, according to the inspection method of the present invention, it is possible to perform a high-precision inspection in a short time so that sufficient contrast can be obtained for image processing even for an inspection object made of a transparent material. Can do.
[0027]
That is, the inspection object is light-transmitting, and a reflection mirror is disposed on the back of the inspection object, and the reflected image transmitted by the reflection mirror is transmitted again through the inspection object, and the inspection object Since the combined image with the reflected image directly reflected on the surface is taken into the camera, the light from the light source floats up the outer peripheral edge of the inspection object on the transparent inspection object, and the light passing through the inspection object is reflected Since the outer peripheral edge of the inspection object is further lifted when it is reflected by the mirror and passes through the inspection object again, the camera can capture the outer peripheral edge of the inspection object on the transparent inspection object well. Thus, a good inspection result can be obtained.
[0028]
In addition, when the object to be inspected is a transparent substrate of a liquid crystal display element, it is possible to raise the outer peripheral edge well even for fine inspection objects such as the wiring of the transparent electrode formed on the substrate. A good inspection can be performed.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining an embodiment of an inspection method according to the present invention. FIG. 2 is a front view of the main part of FIG. 1. FIG. 3 is a longitudinal sectional view showing a general liquid crystal display element. Explanation】
DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2, 2A, 2B Transparent substrate 4, 4A, 4B Transparent electrode 7 Liquid crystal 9 Leading wiring 10 Ring light guide 11 CCD camera 12 Macro lens 13 Reflecting mirror 15 Image processing apparatus

Claims (2)

In an inspection method in which light from a light source is captured as an image into a camera through an inspection object, and the captured image is analyzed by an image processing device,
The inspection object is light-transmitting, and a reflection mirror is disposed on the back of the inspection object, and a transmission image in which reflected light from the reflection mirror is transmitted again through the inspection object, and the surface of the inspection object An inspection method using an image processing apparatus, wherein a composite image with a reflected image directly reflected by the camera is captured by the camera. The inspection method using the image processing apparatus according to claim 1, wherein the inspection object is a transparent substrate of a liquid crystal display element on which an image of a transparent electrode is formed.

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