JP2007285995A - Defect detecting method, defect detecting apparatus and defect detecting program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect detecting method or the like capable of surely detecting only a defect of a substrate of an object to be inspected which has the substrate and a component disposed on the substrate and in which the component can be viewed through the substrate from the opposite side of the substrate surface having the component. <P>SOLUTION: The defect detecting method comprises: a step of irradiating the opposite side of the substrate surface with illumination light which is emitted from the opposite side of the substrate surface having the component of the object to be inspected, at an incident angle satisfying the condition that the illumination light entering the substrate is reflected by the substrate surface at an approximate critical angle; and a step of detecting the defect from a photographed image which is obtained by photographing specular reflection light from the substrate surface or another photographed image which is obtained by applying a prescribed compensation process to the above photographed image. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inspection object including a substrate and a component member disposed on the substrate, wherein the component member is visible through the substrate from a side opposite to the side on which the component member is disposed. The present invention relates to a technical field such as a defect detection method and apparatus for detecting defects on a substrate.

  In recent years, detection of defects in a glass substrate used for a back plate of a PDP (plasma display panel) is indispensable with the progress of manufacturing technology of panel type displays. Detection of defects on the glass substrate is also possible by detecting defects on the glass substrate surface opposite to the surface facing the PDP front plate when the PDP is formed, that is, the surface on which the ribs separating the electrodes and phosphors are formed (back surface). It is required that there is no.

  As a defect inspection method for a surface on which a pattern such as an electrode or a rib is formed (hereinafter referred to as a pattern surface), visual inspection has been mainly performed conventionally, but the size of the defect, variety of types, Visual inspection has become difficult due to problems such as the number of pieces. Instead, it is becoming common to use an appearance inspection apparatus for the pattern surface. The basic principle of this appearance inspection is to illuminate the pattern surface, and to image the pattern surface with a line sensor camera or area sensor camera composed of a CCD (Charge Coupled Device) along the inspection area, Based on the captured luminance information (image), defect inspection is performed with a specific algorithm. All defects are detected as luminance information, and illumination conditions for obtaining luminance information are important factors.

  When such an appearance inspection apparatus is diverted to the defect inspection of the back surface of the glass substrate, the detection light is transmitted through the transparent glass substrate, and components such as electrodes and ribs that are different from the defect to be detected existing on the pattern surface In some cases, the reflected light may be detected. Therefore, it is possible to determine whether what appears to be a defect imaged by the line sensor camera is a defect to be detected, such as foreign matter or scratches on the back surface of the glass substrate, or the shape of electrodes, ribs, etc. existing on the pattern surface side. Therefore, accurate inspection was difficult.

For this reason, there is no effective surface defect inspection means for the back surface of the glass substrate, and it still has to rely on visual inspection. In order to solve this problem, Patent Document 1 discloses a transparent flat plate material by disposing an optical system for detection within a range defined by a critical angle of total reflection with respect to the surface of a transparent flat plate material such as a glass substrate. A technique relating to a surface defect inspection apparatus capable of detecting only foreign matter defects existing on the surface is disclosed.
JP-A-5-273137

  However, even by the method described in Patent Document 1, the glass substrate of the PDP back plate is not flat, and electrodes and ribs are formed on the substrate. Therefore, the influence of scattered light (reflected light) from these constituent members As shown in FIG. 10, according to the conventional method, the light reflected by the electrode that is a constituent member of the PDP back plate is reflected, and only defects can be extracted. Can not.

  The present invention has been made in view of the above points, and in detecting a defect of an inspection object in which the constituent member is visible from the side opposite to the side on which the constituent member such as an electrode is disposed, It is an object of the present invention to provide a defect detection method and the like that can reliably detect only defects without being affected by components such as the electrodes.

  In order to solve the above-mentioned problem, the invention described in claim 1 includes a substrate and a component member disposed on the substrate, and the component member from a side opposite to the side where the component member is disposed. In the defect detection method for detecting defects of the substrate in the inspection object that is visible through the substrate, from the side opposite to the side on which the constituent members are arranged with respect to the substrate surface of the inspection object An illumination step of irradiating the substrate surface with an incident angle such that the illumination light incident on the substrate is reflected in the vicinity of a critical angle of the substrate with respect to the substrate surface; And a detection step of detecting the defect from a captured image obtained by capturing regular reflected light from the captured image or a captured image after performing a predetermined correction process on the captured image. It is a detection method.

In order to solve the above-mentioned problem, the invention according to claim 2 is the defect detection method according to claim ₁ , wherein the refractive index of the atmosphere in which the defect is detected is N ₁ , and the refractive index of the substrate is N _2. The refractive index N ₁ , N ₂ and the critical angle θc satisfy the following expressions (1) and (2).

上記課題を解決するために、請求項３に記載の発明は、請求項２に記載の欠陥検出方法において、前記入射角は、約５０度〜８６．７度であることを特徴とする欠陥検出方法である。

In order to solve the above-mentioned problem, the invention according to claim 3 is the defect detection method according to claim 2, wherein the incident angle is about 50 to 86.7 degrees. Is the method.

  In order to solve the above-mentioned problem, the invention according to claim 4 is the defect detection method according to claim 3, wherein the illumination step and the detection step illuminate and image the detection target object being conveyed. In the defect detection method, the incident angle is about 50 degrees.

  In order to solve the above-mentioned problem, according to a fifth aspect of the present invention, in the defect detection method according to any one of the first to fourth aspects, the detection object includes a front plate and a back plate. The back plate of the plasma display panel, wherein the substrate is a glass substrate disposed on a surface opposite to the surface facing the front plate to form the back plate, and the constituent members include at least electrodes , A dielectric layer, or a partition wall that separates phosphors, and the defect to be detected is at least one of foreign matter adhering to the glass substrate surface, or chipping or scratching of the glass substrate surface This is a defect detection method characterized by the above.

  In order to solve the above-described problem, the invention according to claim 6 is the defect detection method according to any one of claims 1 to 5, wherein the constituent member is patterned on the substrate. This is a defect detection method.

  In order to solve the above-mentioned problem, the invention described in claim 7 includes a substrate and a component member disposed on the substrate, and the component member from a side opposite to the side where the component member is disposed. In the defect detection apparatus for detecting a defect of the substrate in the inspection object that is visible through the substrate, from the side opposite to the side on which the constituent members are arranged with respect to the substrate surface of the inspection object While irradiating the illumination surface with respect to the substrate surface at an incident angle such that the illumination light incident on the substrate is reflected in the vicinity of a critical angle with respect to the substrate surface of the substrate, The defect detection apparatus is characterized in that the defect is detected from a captured image obtained by capturing regular reflected light or a captured image obtained by performing a predetermined correction process on the captured image.

  In order to solve the above problems, an invention described in claim 12 is a defect detection program that causes a computer to function as the defect detection apparatus according to any one of claims 7 to 12.

  According to the present invention, when detecting a defect in an inspection object in which the constituent member is visible from the side opposite to the side on which the constituent member such as an electrode is disposed, the constituent member such as the electrode is affected. Therefore, it is possible to reliably detect only the substrate defects.

I. BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment Hereinafter, the best embodiment for carrying out the present invention will be described with reference to the drawings. The embodiment described below is generated on the back surface of a back plate (which is an example of an inspection object) constituting a PDP (Plasma Display Panel), that is, on the surface of the glass substrate that is the substrate of the PDP back plate. It is an embodiment when the present invention is applied to an inspection system that detects a defect (foreign matter adhering to the glass substrate surface, or chipping or scratching of the glass substrate surface).

<Configuration of PDP back plate>
First, with reference to FIG. 1, the PDP back plate to be inspected will be described in detail. FIG. 1 is a cross-sectional perspective view showing an example of the layer configuration of the PDP back plate 100 according to the present embodiment.

  A PDP back plate 100 shown in FIG. 1 includes an address electrode (an example of an electrode) 102, a dielectric layer 103, and a rib (an example of a partition wall separating phosphors) 104 as constituent members in the present invention. As an example, it is laminated and patterned on the glass substrate 101.

  Since the glass substrate 101 is made of transparent glass, the address electrodes 102 and the ribs 104 can be viewed from the surface of the glass substrate 101 (in other words, the back surface of the PDP back plate). ing. Furthermore, when there is a defect, the dielectric layer 103 can also be visually recognized from the surface of the glass substrate 101.

  Further, the glass substrate 101 is located on the surface of the PDP back plate 100 opposite to the surface facing the PDP front plate (not shown). Then, illumination light is irradiated from the side (downward in FIG. 1) opposite to the side where the constituent members such as the address electrodes 102 are disposed, and the surface of the glass substrate 101 is imaged.

  The PDP back plate 100 in the present embodiment has a thickness of about 2.8 mm, and the size of the defect to be detected generated in the glass substrate 101 is about 0.4 mm in diameter.

  An object of the present invention is to image only the surface of the glass substrate 101 and detect only a defect generated in the glass substrate 101 without being affected by the constituent members of the PDP back plate 100.

<Configuration and function of inspection system>
Next, the configuration and function of the inspection system according to the first embodiment will be described with reference to FIGS.

  FIG. 2 is a diagram illustrating a schematic configuration example of the inspection system according to the first embodiment.

  In the inspection system S shown in FIG. 2, the illumination unit 3 applies white light to the surface of the glass substrate 101 of the PDP back plate 100 placed on the workpiece transfer stage 2 (below the PDP back plate 100 in FIG. 2). The glass substrate 101 is imaged by the line sensor camera 4 and the captured image is acquired by an image processing unit of an inspection terminal described later.

  A band-pass filter 5 is provided on the front surface of the line sensor camera 4 and is configured to transmit only a specific wavelength region of light obtained from the surface of the glass substrate 101. More specifically, the transmission wavelength band of the bandpass filter 5 is designed so that only the light in the wavelength band in which the reflected light amount obtained from the glass substrate 101 is larger than the reflected light amount obtained from the constituent members such as the address electrode 102 is transmitted. Has been.

  FIG. 3 shows an example of the amount of reflected light with respect to light of each wavelength of the glass substrate 101, the address electrode 102, the dielectric layer 103, and the rib 104. According to the figure, particularly in the wavelength band of 380 nm to 450 nm, the amount of reflected light from the constituent members such as the address electrode 102 is smaller than the amount of reflected light of the glass substrate 101. Therefore, the transmission wavelength band of the bandpass filter 5 in the present embodiment is designed as 380 nm to 450 nm (blue filter), and the line sensor camera 4 receives only light in the wavelength band and covers the surface of the glass substrate 101. It is configured so that imaging can be performed. Therefore, the line sensor camera 4 can be configured not to receive the reflected light from the constituent members such as the address electrodes 102 and the ribs 104, in other words, the constituent members such as the address electrodes 102 are not imaged.

  Then, the glass substrate 101 of the PDP back plate 100 is sequentially captured by the line sensor camera 4 while the PDP back plate 100 is transported on the work transport stage 2 that is transport-controlled by a stage control device (not shown), and the image The (captured image) data is output to the inspection terminal 1 via the communication cable. As the line sensor camera 4, a generally used CCD camera can be used.

  For example, a general-purpose personal computer can be applied to the inspection terminal 1. As shown in FIG. 2, a stage (not shown) that inputs data of a captured image captured by the line sensor camera 4 and controls the workpiece transfer stage 2. An external device connection unit 11 connected to a light source control device (not shown) for controlling the control device and the illumination unit 3, the captured image data, various setting data, an OS (operating system), and an application program (for example, a defect of the present invention) A control unit (mainly including a hard disk, ROM, work RAM, video RAM, etc.) 12 for storing a detection program) and a CPU, and a control for acquiring the captured image data and performing various image processes. Unit 13 and a display unit for displaying information indicating the captured image and the inspection result (for example, A liquid crystal display) 14; an operation unit 15 (for example, a keyboard, a mouse, etc.) that inputs an operation instruction from an inspector (operator) and outputs the instruction signal to the control unit 13; The image processing unit 17 is configured to perform image processing together with the communication unit 16 and the control unit 13 for communicating with each other, and these components are connected to each other via a bus 18. Note that the stage control device and the light source control device may be provided in the inspection apparatus 1.

  And the control part 13 cooperates with the image process part 17 by executing the defect detection program memorize | stored in the memory | storage part 12, with respect to the said captured image, the noise removal process, differentiation process, and binary which are mentioned later Various image processing such as digitization processing is performed. It should be noted that if the processing content is simple or can satisfy the tact, the image processing unit 17 is not provided, and the processing by the control unit 13 is sufficient.

  The control unit 13 includes a CPU (Central Processing Unit) having a calculation function, various programs (for example, a defect detection program of the present invention), a ROM (Read Only Memory) for storing data, and a RAM (Work Memory) ( Random Access memory) and the like, and controls the entire components in the inspection apparatus 1. Moreover, the control part 13 functions as a data acquisition means and defect detection means of this invention in cooperation with another structural member by executing a defect detection program.

<Defect detection process>
Next, the operation of the inspection system S according to the present embodiment will be described with reference to FIG.

  FIG. 4 is a flowchart showing a defect detection process in the inspection terminal 1, which is executed based on the control of the control unit 13, and the surface of the glass substrate 101 of the PDP back plate 100 is imaged by the line sensor camera 4, and the captured image data Is input to the inspection terminal 1 via a communication cable or the like to start processing.

  In addition, the illumination part 3 shall always irradiate light with respect to the PDP backplate 100, while the defect detection process is performed. In addition, since imaging is performed while the PDP back plate 100 is being conveyed, it is desirable that the illumination unit 3 irradiates with a certain amount of light until the imaging of the single PDP back plate 100 is completed. In addition, captured images and detection results obtained in the respective steps can be displayed on the display unit 14, so that an inspector (operator) can also confirm it visually.

  In the inspection terminal 1, the control unit 13 functions as a data acquisition unit, and images captured sequentially from the line sensor camera 4 are input as data via a communication cable, and captured image data as illustrated in FIG. Obtain (step S1). Although the defective part is imaged darker than other parts, the defective part is further emphasized by performing image processing on the acquired captured image data. Specifically, the control unit 13 performs various types of image processing such as noise removal processing, differentiation processing, binarization processing, and hole filling processing on the captured image data acquired in cooperation with the image processing unit 17. Perform (step S2). The image processing (predetermined correction processing) may be any image processing technique that is conventionally known as long as the defect portion can be emphasized to facilitate extraction. Then, an image in which a defective portion as shown in FIG. 5B is emphasized darker than other portions is acquired.

  Subsequently, the control unit 13 detects a defect (step S3). At this time, after detecting a defect candidate suspected of having a defect to be detected, the size (area) of the detected defect candidate is measured, and a defect candidate whose size is larger than a predetermined threshold (for example, 3 mm) is determined. , Configured to detect as a defect. A defect candidate whose size is equal to or smaller than a predetermined threshold is so small as to have a small effect on the quality of the PDP back plate 100, and therefore is excluded from a defect detection target. In other words, a size having an effect on the quality of the PDP back plate 100 Only the defects can be detected. The predetermined threshold is set in advance by the inspector and stored in the storage unit 12 or the like, and the predetermined threshold is read from the storage unit 12 or the like when the size of each defect candidate is compared with the predetermined threshold. It is configured as follows.

  And the control part 13 and the display part 14 function as a presentation means, for example, display the detected defect as a defect detection result on the display part 14, and show (notify) to an inspector (step S4), and complete | finish a process. . Further, the position coordinates, size (size), and the like of the detected defect along with the imaged image data may be stored in the storage unit 12 and managed and stored as defect data.

  As described above, according to the above embodiment, the constituent members such as the address electrodes 102 arranged on the glass substrate 101 are from the back surface of the PDP back plate 100, that is, the side on which the constituent members are arranged. When visible from the opposite side through the glass substrate 101, only the specific wavelength region of the light obtained from the glass substrate 101 is received and imaged to be affected by the constituent members such as the address electrode 102. In addition, only defects generated in the glass substrate 101 can be reliably detected.

  Further, since the band pass filter 5 is used to capture only a specific wavelength region of light obtained from the surface of the glass substrate 101, a fluorescent lamp can be used as illumination light, and the inspection system S is configured at a lower cost. can do.

  In the above-described embodiment, the case has been described in which the defect is imaged darker than the other portions with respect to the light amount of the glass substrate 101. Conversely, the defect may be imaged brightly.

  Furthermore, in the above-described embodiment, the bandpass filter 5 that transmits only light in a specific wavelength region is disposed on the front surface of the line sensor camera 4. However, the bandpass filter 5 is disposed on the front surface of the illumination unit 3. You may comprise (refer FIG. 6 (A)). When the band pass filter 5 is not used, the illumination unit 3 is configured by the blue illumination light source 3A, and the PDP back plate 100 may be configured to irradiate light in a specific wavelength region (FIG. 6B). reference).

  Further, from the captured image of the PDP back plate 100, a defect candidate that is suspected of being a defect to be detected is detected, the size of each detected defect candidate is further measured, and a defect candidate that is larger than a predetermined threshold is Since it is configured to detect as a defect, it is possible to detect only a defect having a size (area) that has a large influence on the quality of the PDP back plate 100. Further, if the predetermined threshold is configured to be freely set by the inspector, it is possible to detect a defect with a desired detection sensitivity.

  Furthermore, in the above-described embodiment, various image processing is performed on the captured image. However, when the captured image according to the acquired captured image data can sufficiently extract a defective portion so that the size can be easily measured. However, the image processing may not be performed.

  In the above-described embodiment, the defect detection result is displayed on the display unit 14 as the presentation unit. However, the defect detection result is printed and presented to the inspector using a printing device or the like as the presentation unit. May be.

  Further, in the above-described embodiment, the defect detection method of the PDP back plate 100 having the patterned constituent members such as the address electrodes 102 as the constituent members on the glass substrate 101 has been described. However, the present invention is not limited to this. Rather than detecting a defect in a color filter in which a component such as a colored layer is coated on a transparent substrate, or detecting a defect in the resin film surface of a coated film such as a vapor-deposited film or a multilayer film It can also be applied to.

II. Second Embodiment Next, a second embodiment which is another embodiment according to the present application will be described.

  In the first embodiment, only the specific wavelength region of the light obtained from the glass substrate 101 of the PDP back plate 100 is imaged, so that the glass substrate 101 is not affected by reflected light from components such as the address electrode 102. In the second embodiment, the reflected light from the constituent members such as the address electrode 102 is defined by defining the incident angle when illuminating the glass substrate 101 with the illumination light. And the like, and only defects that occur in the glass substrate 101 are detected.

  Specifically, the light irradiated on the glass substrate 101 is divided into light reflected (including scattering) on the surface of the glass substrate 101 and light incident on the glass substrate 101. Among these, the light incident on the glass substrate 101 is then reflected by the constituent members such as the address electrode 102, and the reflected light from the constituent members is confined in the glass substrate 101. That is, the illumination light is irradiated onto the glass substrate 101 at an incident angle such that the reflected light from the component member is then reflected in the vicinity of the critical angle with respect to the surface of the glass substrate 101 (surface in contact with the atmosphere). Thereby, only the regular reflected light (including scattered light and reflected light scattered by the defect) reflected on the surface of the glass substrate 101 is imaged by the line sensor camera 4.

<Defect inspection method>
Next, the defect inspection method according to the second embodiment will be specifically described with reference to FIG.

  FIG. 7 is an explanatory diagram of the defect inspection method according to the second embodiment.

The illumination unit 3 irradiates the glass substrate 101 with illumination light at an incident angle θ ₁ . That is, it is configured such that light (broken line in the figure) incident on the glass substrate 101 is repeatedly reflected in the vicinity of the critical angle θc with respect to the glass substrate 101 surface (surface in contact with the atmosphere) inside the glass substrate 101. The critical angle θc can be expressed by equation (2) under the condition of equation (1), where N _{1 is} the refractive index of the atmosphere and N ₂ is the refractive index of the glass substrate 101 material.

そして、スネルの法則より、入射角θ_１は、以下の式（３）として規定することができる。

And from Snell's law, incident angle (theta) ₁ can be prescribed | regulated as the following formula | equation (3).

例えば、大気の屈折率Ｎ_１が約１．００、ガラス基板１０１材料の屈折率Ｎ_２が約１．５５である場合には、臨界角θｃは４０．１度、入射角θ_１は８６．７度となる。

For example, the refractive index _{N 1} of air is about 1.00, when the refractive index _{N 2} of the glass substrate 101 material is about 1.55, the critical angle θc is 40.1 °, the incident angle theta ₁ is 86. 7 degrees.

  The other configurations and functions of the inspection system S are the same as those in the first embodiment except that the bandpass filter 5 is not used, and thus the description thereof is omitted.

As described above, when the refractive index N ₁ of the atmosphere is about 1.00 and the refractive index N ₂ of the glass substrate 101 material is about 1.55, the incident angle θ ₁ of the illumination light is 86.7 degrees. Most preferred. However, the size and camera sensitivity of each member in the optical system composed of the PDP back plate 100 to be inspected, the illumination unit 3 and the line sensor camera 4, or the transfer of the work transfer stage 2 that transfers the PDP back plate 100 The incident angle θ ₁ of the illumination light may be limited by a mechanism or the like. Hereinafter, this will be specifically described with reference to FIG.

  FIG. 8 is a schematic view of the transfer mechanism in the workpiece transfer stage 2. Note that a mechanism (for example, a roller support portion) other than the roller of the workpiece transfer stage 2 is omitted for simplicity of illustration. Further, in the drawing, the size of the roller of the work transfer stage 2, the PDP back plate 100, the constituent members of the PDP back plate 100, etc. are shown in an easy-to-understand manner to reflect the reflection angle of the illumination light. Is different.

When the workpiece transfer stage 2 is configured by a roller conveyor having a roller radius r and a roller pitch d, the limit incident angle θ _1th is expressed by the following equation (4).

なお、限界入射角θ_１ｔｈとは、式（３）にて求めた臨界角θｃに対応する入射角θ_１に最も近く、かつ、ワーク搬送ステージ２の搬送機構による制限を考慮した場合に設計可能な入射角である。

The limit incident angle θ _1th is closest to the incident angle θ ₁ corresponding to the critical angle θc obtained by the equation (3), and can be designed in consideration of the limitation by the transfer mechanism of the workpiece transfer stage 2. The incident angle is large.

For example, when the roller radius r is 15 mm and the roller pitch d is 83 mm, the limit incident angle θ _1th is 50 degrees according to the equation (4).

9, the incident angle theta ₁ is an example of a captured image of the glass substrate 101 side of the different PDP back plate 100. The captured image is a captured image before the above-described defect detection process (see FIG. 4) is performed, that is, before the image process (predetermined correction process) is performed. As shown in the figure, the defect can be imaged more clearly as the incident angle θ _{1 of the} illumination light emitted from the illumination unit 3 is closer to the limit incident angle θ _1th 50 degrees.

As described above, according to the above embodiment, the constituent members such as the address electrodes 102 arranged on the glass substrate 101 are from the back surface of the PDP back plate 100, that is, the side on which the constituent members are arranged. When it is visible through the glass substrate 101 from the opposite side, the illumination light is applied at an incident angle θ ₁ that is reflected in the vicinity of the critical angle θc with respect to the surface of the glass substrate 101 (surface in contact with the atmosphere). By irradiating, only the regular reflected light (including scattered light and reflected light scattered by the defect) reflected on the surface of the glass substrate 101 is received by the line sensor camera 4 and imaged, thereby address electrodes 102 and the like. Only the defect which arose in the glass substrate 101 can be detected reliably, without receiving the influence of this structural member.

Further, for example, when the refractive index N _{1 of the} atmosphere is about 1.00, the refractive index N ₂ of the glass substrate 101 material is about 1.55, and the critical angle θc is 40.1 degrees, the incident angle θ ₁ is It is preferable to irradiate illumination light at 86.7 degrees.

Furthermore, even when the incident angle θ ₁ is limited by the size of the entire optical system, the transport mechanism of the work transport stage 2 that transports the PDP back plate 100, the incident angle θ ₁ is approximately 50 degrees to 86. It is preferable that the angle is 7 degrees. In particular, when defect detection is performed on the PDP back plate 100 being transferred by the workpiece transfer stage 2, the roller radius r of the workpiece transfer stage 2 is 15 mm and the roller pitch d is 83 mm. The incident angle θ ₁ is preferably 50 degrees which is the limit incident angle θ _1th .

In addition, this invention can also be implemented combining the 1st Embodiment and 2nd Embodiment which were mentioned above. For example, the illumination unit 3 irradiates the surface of the glass substrate 101 with illumination light at an incident angle θ _{1 of} 50 degrees, and the surface of the glass substrate 101 is passed through the bandpass filter 5 having a transmission wavelength band of 380 nm to 450 nm. Take an image. Thereby, the inspection system S which can detect the defect of the glass substrate 101 reliably by the synergistic effect of 1st Embodiment and 2nd Embodiment is realizable. This is particularly effective when the limit incident angle θ _1th is greatly limited by the transport mechanism.

It is a cross-sectional perspective view which shows an example of the laminated constitution of the PDP backplate 100 concerning 1st and 2nd embodiment. It is a figure showing an example of outline composition of an inspection system concerning a 1st embodiment. It is an example of the reflected light quantity with respect to the light of each wavelength of the glass substrate 101 and each structural member. It is a flowchart which shows the defect detection process in the inspection terminal. (A) It is an example of the captured image of the glass substrate 101 of the PDP back plate 100. (B) It is an example of the captured image after image processing. It is a principal part figure of the test | inspection system concerning other embodiment. It is explanatory drawing of the defect inspection method concerning 2nd Embodiment. FIG. 3 is a schematic diagram of a transfer mechanism in the workpiece transfer stage 2. It is an example of the captured image of the glass substrate 101 of the PDP backplate 100 from which incident angle (theta) ₁ differs. It is the captured image acquired by the conventional method.

Explanation of symbols

S Inspection System 1 Inspection Terminal 11 External Device Connection Unit 12 Storage Unit 13 Control Unit 14 Display Unit 15 Operation Unit 16 Communication Unit 17 Image Processing Unit 18 Bus 2 Work Transfer Stage 3 Illumination Unit 3A Blue Illumination Light Source 4 Line Sensor Camera 5 Illumination Unit 100 PDP back plate 101 glass substrate 102 address electrode 103 dielectric layer 104 rib r roller radius d roller pitch

Claims (13)

A substrate and a component disposed on the substrate, wherein the component is visible through the substrate from a side opposite to the side where the component is disposed. In the defect detection method for detecting defects,
Illumination light emitted from the side opposite to the side on which the constituent members are arranged with respect to the substrate surface of the inspection object, and the illumination light incident on the substrate is near a critical angle of the substrate with respect to the substrate surface An illumination process for irradiating the substrate surface with an incident angle that is reflected by
A detection step of detecting the defect from a captured image obtained by imaging regular reflected light from the substrate surface or a captured image after performing a predetermined correction process on the captured image;
A defect detection method characterized by comprising: The defect detection method according to claim 1,
When the refractive index of the atmosphere in which defect detection is performed is N ₁ , and the refractive index of the substrate is N ₂ , the refractive indexes N ₁ , N ₂ , and the critical angle θc are expressed by the following equations (1) and ( 2) A defect detection method characterized by satisfying the above.

The defect detection method according to claim 2,
The defect detection method, wherein the incident angle is about 50 to 86.7 degrees. The defect detection method according to claim 3,
2. The defect detection method according to claim 1, wherein when the illumination process and the detection process perform illumination and imaging on the detection target object being conveyed, the incident angle is about 50 degrees. In the defect detection method as described in any one of Claims 1 thru | or 4,
The detection object is the back plate of the plasma display panel composed of a front plate and a back plate,
The substrate is a glass substrate disposed on a surface opposite to the surface facing the front plate to form the back plate,
The component is at least one of an electrode, a dielectric layer, and a partition wall that separates the phosphor,
The defect detection method, wherein the defect to be detected is at least one of a foreign matter adhering to the glass substrate surface or a chipping or a flaw on the glass substrate surface. In the defect detection method according to any one of claims 1 to 5,
The defect detection method, wherein the component member is patterned on the substrate. A substrate and a component disposed on the substrate, wherein the component is visible through the substrate from a side opposite to the side where the component is disposed. In a defect detection device for detecting defects,
Illumination light emitted from the side opposite to the side on which the constituent members are arranged with respect to the substrate surface of the inspection object, and the illumination light incident on the substrate is near a critical angle of the substrate with respect to the substrate surface A predetermined correction process was performed on a captured image obtained by imaging regular reflected light from the substrate surface or the captured image while irradiating the substrate surface with an incident angle reflected by A defect detection apparatus that detects the defect from a later captured image. The defect detection apparatus according to claim 7,
When the refractive index of the atmosphere in which defect detection is performed is N ₁ , and the refractive index of the substrate is N ₂ , the refractive indexes N ₁ , N ₂ , and the critical angle θc are expressed by the following equations (1) and ( 2) A defect detection apparatus characterized by satisfying the above.

The defect detection apparatus according to claim 8,
The defect detection apparatus, wherein the incident angle is about 50 degrees to 86.7 degrees. The defect detection apparatus according to claim 9, wherein
The defect detection apparatus according to claim 1, wherein when the detection object being conveyed is illuminated and imaged, the incident angle is about 50 degrees. In the defect detection device according to any one of claims 7 to 10,
The detection object is the back plate of the plasma display panel composed of a front plate and a back plate,
The substrate is a glass substrate disposed on a surface opposite to the surface facing the front plate to form the back plate,
The component is at least one of an electrode, a dielectric layer, and a partition wall that separates the phosphor,
The defect detection apparatus according to claim 1, wherein the defect to be detected is at least one of a foreign matter adhering to the glass substrate surface or a chipping or a flaw on the glass substrate surface. The defect detection apparatus according to any one of claims 7 to 11,
The defect detection apparatus, wherein the component member is patterned on the substrate.   A defect detection program for causing a computer to function as the defect detection apparatus according to any one of claims 7 to 12.

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