JPH07270335A - Method and device for imaging inspection - Google Patents

Abstract

PURPOSE:To precisely judge a defect by a method wherein a position defined by position information of a candidate section having a defect stored in a memory is imaged with a high magnification as an imaging-attention position. CONSTITUTION:An imaging information taken by the imaging with a low magnification by a CCD camera 15 is inputted to an image processing device 17, then the presence or absence of a condensation candidate section of a spacer S is discriminated by a defective candidate discrimination section 19. Next, gravity coordinates of the condensation candidate section are calculated to be stored in a memory means 21. An imaging position control section 27 of a host computer 25 controls the action of an XY stage 1 so that a position defined by the position information from the memory means 21 is set to a central imaging position of the camera 15 as an imaging attention position. Thereby, the stage 1 is driven so that the condensation candidate section of a glass plate G is sequentially imaged with a high magnification by the camera 15. The information obtained by the imaging with the high magnification by the camera 15 is inputted to the device 17, then a defect-judgment section 23 counts the number of spacers. The defect is judged by checking whether the number exceeds a condensation-allowance number.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging type inspection method and apparatus, and more particularly to an imaging type inspection method and apparatus when a defect to be detected is small with respect to the size of an inspection area.

[0002]

2. Description of the Related Art In a liquid crystal display device, plastic or glass spherical particles having a uniform size (particle size) are used as spacers for the purpose of maintaining a uniform gap between glass plates enclosing liquid crystals. In this case, it is required that the spacers composed of spherical particles are evenly dispersed on the glass plate, and if the spacers are aggregated on the glass plate, that part is observed as a black dot and the liquid crystal The display element itself becomes a defective product.

In view of this, in the production of a liquid crystal display element, after the spacers are dispersed on the glass plate, the aggregation state of the spacers on the glass plate is inspected. While the particle diameter of the spacer is several microns, the size of the glass plate of the liquid crystal display element, that is, the size of the inspection area is large, which is more remarkable as the size of the liquid crystal panel has increased in recent years.

As an imaging type inspection method that enables an efficient and accurate inspection when a defect to be detected is small with respect to the size of the inspection area, as described in JP-A-3-187.
As disclosed in Japanese Patent Laid-Open No. 08-2008, a defect position is detected by scanning a laser beam over the entire inspection area having a relatively large area of the inspection object, and the defect position detected by this laser beam scanning is detected. There is a method of performing a precise inspection by an optical inspection means using an optical microscope and a video camera according to an operator's instruction.

[0005]

The above-mentioned imaging type inspection method achieves the intended purpose, but there are two types of inspection means, that is, inspection means by laser beam scanning and inspection means using an optical microscope and a video camera. The inspection means is required, and the inspection means by laser beam scanning requires a complicated scanning optical system for scanning the laser beam, and more control elements are required, and the control system becomes complicated. For these reasons, the inspection apparatus based on this imaging type inspection method is large-scale and expensive.

The present invention has been made by paying attention to the above-mentioned problems, and requires a plurality of types of inspection means for the inspection when the defects to be detected are small with respect to the size of the inspection area. Fast and reliably with a simple configuration without
Moreover, it is an object of the present invention to provide an imaging type inspection method and apparatus that can be performed without requiring many manual operations.

[0007]

According to the present invention, an object as described above is reduced in the entire inspection area of the object to be inspected in the image inspection method for detecting a defect from image information of the object to be inspected. The imaging means scans and images at a magnification, the defect candidate portion is identified from the imaging information by the scanning imaging, the position information of the defect candidate portion is stored in the storage portion, and the defect candidate portion stored in the storage portion is stored. This is achieved by an imaging type inspection method characterized in that a position defined by the position information is taken as a target imaging position at a high magnification by an imaging means, and a defect is judged from the imaging information obtained by the high magnification imaging.

In order to achieve the above-mentioned object, an image pickup type inspection apparatus according to the present invention is an image pickup type inspection apparatus which detects a defect from image pickup information of an object to be inspected, and an image of which optical magnification is variable to image the object to be inspected. Means, scanning moving means for relatively scanning and moving the object to be inspected and the image pickup means, and relatively moving the object to be inspected and the image pickup means by the scanning and moving means to obtain a low magnification by the image pickup means. A defect candidate part identifying part for identifying a defect candidate part from the imaged information of the inspected object, storage means for storing position information of the defect candidate part identified by the defect candidate part identifying part, and the imaging part. Is set to a high magnification to control the operation of the scanning moving means so that the position defined by the position information of the defect candidate portion stored in the storage means is set to the image pickup position by the image pickup means. And position control means is characterized by having a defect determination unit for performing a defect determination from the imaging information of the object to be inspected picked up at a high magnification by the imaging means.

[0009]

[Operation] According to the above-mentioned configuration, first, the defect candidate portion is identified by the imaging information obtained by scanning and imaging the entire inspection region of the inspection object at a low magnification, and the position information of this defect candidate portion is stored in the storage means. Is done. Then, the position defined by the position information of the defect candidate portion stored in the storage means is taken as a target image pickup position at a high magnification, and the defect is precisely determined based on the image pickup information obtained by the high magnification image pickup. Be seen.

[0010]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of an image pickup type inspection apparatus according to the present invention. In FIG. 1, reference numeral 1 indicates an XY stage. The XY stage 1 has an opening at the center, and an object to be inspected, for example, a glass plate G for a liquid crystal display device is placed on the stage, and the glass plate G is used as a scanning moving means.
Is displaced in the XY directions. The symbol S schematically shows a spacer made of spherical particles.

Below the XY stage 1, an illumination device 3 for illuminating an object to be inspected is arranged. An optical microscope 5 is arranged above the XY stage 1. The optical microscope 5
Three objective lenses 9, 11, and 13 are mounted on the electric revolver 7, and a CCD camera 15 is connected to the eyepiece side. The CCD camera 15 picks up an image of the glass plate G on the XY stage 1 with three optical magnifications of low, medium, and high by selectively using the objective lenses 9, 11, and 13 by the electric revolver 7. The image pickup by the CCD camera 15 is a visible image picked up by the transmitted light that has passed through the glass plate G from the illumination device 3.

An image processing device 17 is connected to the CCD camera 15. The image processing device 17 is a CCD camera 1.
The image signal (imaging information) output by 5 is input to perform preprocessing and analysis of the image signal, and the defect candidate portion is identified from the imaging information of the glass plate G captured by the CCD camera 15 at a low magnification. In this case, the defect candidate portion identifying portion 19 for identifying the presence or absence of the agglomerated portion of the spacer S, the storage means 21 for storing the position information of the defect candidate portion identified by the defect candidate portion identifying portion 19, and the CCD camera at high magnification. It also includes a defect determining unit 23 that determines a defect based on the imaged information of the glass plate G imaged by 15.

The image processing device 17 is a host computer 2.
5 is bidirectionally connected for data communication. The host computer 25 manages the image processing device 17 and manages the XY
The operation of the stage 1, the illumination device 3, and the electric revolver 7 is controlled, and the optical microscope 5 is controlled by the electric revolver 7.
The optical position of the XY stage 1 is set to a high value, and the operation of the XY stage 1 is controlled so that the position defined by the position information of the defect candidate portion stored in the storage unit 21 becomes the image capturing position of the CCD camera 15. The control unit 27 is included.

FIG. 2 is a model diagram in which the glass plate G in which the spacers S are dispersed is observed from above. In FIG.
Reference A indicates a field frame during low-magnification imaging, and reference B indicates a field frame during high-magnification imaging. Next, the procedure of the spacer dispersion inspection by the imaging type inspection device having the above-mentioned configuration will be described.

First, the electric revolver 7 is driven by the operation command from the host computer 25 to set the optical magnification of the optical microscope 5 to a low magnification, and the XY stage 1 is intermittently driven by the operation command from the host computer 25 to drive the glass plate. G is moved by scanning with respect to the optical microscope 5, and the field frame A
The glass plate G is imaged by the CCD camera 15 every time. This low-magnification imaging is performed over the entire surface of the glass plate G for each field frame A, that is, the entire inspection region.

The image processing device 17 inputs image pickup information obtained by low-magnification image pickup from the CCD camera 15, and the defect candidate portion identifying portion 19 identifies the presence or absence of the aggregation candidate portion (defect candidate portion) of the spacer S. The presence / absence of the aggregation candidate portion of the spacer S is determined by whether or not there is an island-shaped spacer image having a reference pixel number determined by the aggregation allowable number of the spacer S and the particle size of the spacer S. The identification condition is instructed to the image processing device 17 from the host computer 25 in advance.

FIG. 3 shows the relationship between the particle size of the spacer S and the reference number of pixels when the number of spacers S allowed to aggregate is five. FIG. 4 exemplifies a low-magnification imaged image in one visual field frame A. In this imaged image, the portion indicated by the symbol E is identified as an aggregation candidate portion of the spacer S due to the reference pixel number excess. .

Next, the barycentric coordinates of the aggregation candidate portion E are calculated, and this is written in the storage means 21 as the position information of the defect candidate portion. When the low-magnification imaging over the entire surface of the glass plate G is finished and the aggregation candidate portion E does not exist, the inspection is finished because there is no defective portion. On the other hand, when the aggregation candidate portion E exists, the electric revolver 7 is driven by the operation command from the host computer 25 to set the optical magnification of the optical microscope 5 to a high magnification, and the storage unit 21 of the image processing apparatus 17 is set. The position information of each aggregation candidate portion E stored by is sequentially transmitted to the host computer 25. The image pickup position control unit 27 of the host computer 25 uses the position defined by the position information of the aggregation candidate portion E from the storage unit 21 as the image pickup position of interest for the CCD.
The XY stage 1 should be set to the center position of the image pickup by the camera 15.
Control the behavior of.

As a result, the XY stage 1 is driven, each aggregation candidate portion E of the glass plate G is successively positioned at the image pickup position by the CCD camera 15, and each aggregation candidate portion E is imaged at high magnification. FIG. 5 shows an example of high-magnification imaging of this aggregation candidate portion E. The image processing device 17 inputs the imaging information by high-magnification imaging from the CCD camera 15, and the defect determination unit 23 counts the number of spacers in the aggregation candidate portion E by the image analysis processing for each aggregation candidate portion E. The defect is judged by whether or not the number exceeds the allowable aggregation number.

The above-mentioned high-magnification imaging and counting of the number of spacers are performed for all the aggregation candidate portions E determined by the position information stored in the storage means 21, and the aggregation candidate portions E are obtained.
The defect determination is performed for all of the above, and the inspection is completed by outputting the result. In the above-described embodiment, the low-magnification image pickup uses the low-magnification objective lens 9 of the optical microscope 5, and the high-magnification image pickup uses the high-magnification objective lens 13. The low-magnification objective lens 9 is used for high-magnification imaging, the medium-magnification objective lens 11 is used for high-magnification imaging, and the low-magnification objective lens 11 is used for low-magnification imaging. A magnifying objective lens 13 may be used, and these may be appropriately set depending on the relationship between the entire inspection area and the size of the defect to be detected.

[0021]

As can be understood from the above description, according to the imaging type inspection method and apparatus according to the present invention, first, the defect candidate portion is detected by the imaging information by the scanning imaging of the entire inspection region of the inspection object at a low magnification. The position information of the defect candidate portion is identified and stored in the storage unit, and the position defined by the position information of the defect candidate unit stored in the storage unit is used as a target image capturing position to perform high-magnification imaging. Since the defect is precisely judged based on the image information obtained by the high-magnification image pickup, the whole inspection is performed only by the low-magnification image pickup, and the inspection is performed when the defect to be detected is small with respect to the size of the inspection area. However, it does not require a plurality of types of inspection means, and has a simple structure, and can be performed at high speed, reliably, and without requiring many manual operations.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an imaging type inspection apparatus according to the present invention.

FIG. 2 is a model diagram in which a glass plate in which spacers are dispersed is observed from above.

FIG. 3 is a graph showing the relationship between the particle size of spacers and the number of reference pixels.

FIG. 4 is an explanatory diagram illustrating a low-magnification captured image in one field frame.

FIG. 5 is an explanatory diagram illustrating an example of high-magnification imaging of an aggregation candidate portion.

[Explanation of symbols]

 1 XY Stage 5 Optical Microscope 15 CCD Camera 17 Image Processing Device 19 Defect Candidate Part Identification Unit 21 Storage Means 23 Defect Judgment Unit 25 Host Computer 27 Imaging Position Control Unit G Glass Plate S Spacer

Claims (2)

[Claims] 1. An image pickup type inspection method for detecting a defect from image pickup information of an object to be inspected, wherein image pickup information is scanned by an image pickup device at a low magnification over the entire inspection region of the object to be inspected, and image pickup information by the scanning image pickup. The defect candidate portion is further identified, the position information of the defect candidate portion is stored in the storage unit, and the position defined by the position information of the defect candidate portion stored in the storage unit is set as the target imaging position at high magnification. An image-capturing type inspection method, wherein an image is captured by an image-capturing means, and a defect is determined based on image-capturing information obtained by the high-magnification imaging. 2. An image pickup type inspection apparatus for detecting a defect from image pickup information of an object to be inspected, wherein an image pickup means for changing an optical magnification for picking up an image of the piece to be inspected, and an object to be inspected and the image pickup means are relatively scanned The scanning moving means for moving and the scanning moving means relatively scan-moves the inspected object and the imaging means, and the defect candidate part is identified from the imaging information of the inspected object imaged at a low magnification by the imaging means. A defect candidate portion identifying unit, a storage unit that stores position information of the defect candidate unit identified by the defect candidate unit identifying unit, and an optical magnification of the imaging unit is set to a high magnification and stored in the storage unit. Image pickup position control means for controlling the operation of the scanning movement means so as to set the position defined by the position information of the defect candidate portion to the image pickup position by the image pickup means, and the object picked up at a high magnification by the image pickup means. An image pickup type inspection apparatus, comprising: a defect determination unit that determines a defect based on image pickup information of an inspection object.