JPH09210660A - Image pick-up inspection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alter the optical magnification easily depending on the size of microparticle by providing an image pick-up means, an optical magnification altering means, a scanning/moving means, a focal position adjusting means, means for varying the quantity of light being projected from a light source to an object, and a defect decision means. SOLUTION: An optical magnification varying motor 16 is driven with an operation command from a controller 19 to turn a revolver 15 and the optical magnification of an optical microscope 4 is set optimally depending on the particle size of a sample W. A plane light source 17 projects light below the sample W. A CCD camera 5 picks up the image of sample W. Focal position of the microscope 4 is then adjusted to maximize the difference between maximum and minimum densities in the screen of image. Finally, the image information picked up by means of camera 5 is analyzed by an image processor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup type inspection apparatus for detecting microscopic defects in a wide inspection area, and more particularly to a magnification for microparticle agglomeration and foreign matter defects which are difficult to visually determine. The present invention relates to an imaging type inspection device that raises and inspects.

[0002]

2. Description of the Related Art Generally, when a defect to be detected is very small,
A high-magnification optical microscope is used to magnify the object to be inspected, and this is visually inspected or imaged by a CCD camera to inspect for defects. In this case, the higher the magnification of the optical microscope,
While highly accurate defect detection is performed, the observation field of view becomes smaller, the depth of focus becomes shallower, and the wider the inspection area, the longer the inspection takes.

For example, in a liquid crystal display device, in order to maintain a uniform gap between glass plates enclosing liquid crystal,
Translucent plastic or glass spherical particles having a uniform size (particle size) are used as spacers. In this case, a plurality of spherical particle spacers are in contact with each other on a glass plate. Are formed (aggregated), the portion is observed as a black spot, and the liquid crystal display element itself becomes a defective product. In view of this, in the production of the liquid crystal display element, after the spacers are dispersed on the glass plate, the dispersion state of the spacers on the glass plate is inspected.

In order to inspect the dispersion state of such spacers, since the spacer particle size is about 4 to 10 μm, it is necessary to set the magnification of the optical microscope to, for example, about 40 times. Is about 0.2 mm × 0.2 mm, while the size of the glass plate is 28 mm, for example.
Since it is about 0 mm × 180 mm, the inspection takes a lot of time. This has become more remarkable with the recent increase in the size of liquid crystal panels. In addition, in order to carry out the inspection accurately, it is necessary to change the magnification of the optical microscope in accordance with the particle size of the target, adjust the appropriate amount of transmitted light accordingly, and because the depth of focus becomes shallower, Focusing must be performed, which also increases inspection time.

Therefore, as described above, when the object to be detected is small with respect to the size of the inspection area, the image pickup means enables low-magnification by the image pickup means so that the inspection can be performed efficiently and accurately. With scanning imaging over the entire inspection region of the inspected object, the defect candidate portion is identified from the imaging information by the scanning imaging, based on the information of the defect candidate portion, only the defect candidate portion is re-imaged at high magnification, A method for determining a defect is disclosed, for example, in Japanese Patent Application No. 6-72013.

[0006]

However, the inventor of the present invention has found that the above-mentioned imaging type inspection apparatus has the following problems. In other words, while achieving the initial objectives for increasing the size of the inspection area, for the inspection means for changing the optical magnification according to the particle size of the fine particles scattered on the glass plate, the focus by the optical displacement sensor There is only a description of matching, there is no specific description, and when an optical displacement sensor is used, a plurality of types of inspection means are required, which complicates the device configuration and increases the cost.

The object of the present invention is to solve the above-mentioned problems.
It is an object of the present invention to provide an imaging type inspection apparatus that can easily change the optical magnification according to the particle diameter of fine particles with a simple configuration without requiring a plurality of types of inspection means. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0008]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. An image pickup type inspection apparatus of the present invention includes an image pickup unit that optically magnifies and images an object to be inspected, an optical magnification changing unit that changes the optical magnification of the image pickup unit, and an object to be inspected with respect to the image pickup unit. The scanning moving means for moving, the focus position adjusting means for adjusting the focus position of the image pickup means so that the density difference between the maximum density and the minimum density in the image pickup range of the image pickup means becomes maximum, and the light is transmitted to the object to be inspected. A light source for changing the amount of light emitted from the light source to the object to be inspected, and a defect determining unit for determining a defect based on the imaging information of the object to be inspected captured by the imaging unit.

Further, the image pickup type inspection apparatus of the present invention comprises a robot for supplying the object to be inspected to the image pickup position of the image pickup means and discharging the object to be inspected from the image pickup position. According to the above-mentioned means, the light is transmitted from the light source to the object to be inspected, and the imaging means images the transmitted light of the object to be inspected. The focus position adjusting means adjusts the focus position of the image pickup means so that the density difference between the maximum density and the minimum density in the image pickup range of the image pickup means becomes maximum. The defect determining means determines a defect based on the imaged information of the inspection object. The robot supplies the uninspected object to the inspection apparatus and discharges the inspected object from the inspection apparatus.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. Here, FIG. 1 is a perspective view of an image pickup type inspection apparatus according to one embodiment of the present invention, and FIG. 2 is a characteristic of a defocus amount and an image pickup screen density difference of the image pickup type inspection apparatus according to one embodiment of the present invention. FIG. 3 is an observation view of a liquid crystal spacer according to an embodiment of the present invention by transmitted light, and FIG. 4 is a perspective view of an imaging type inspection device according to another embodiment of the present invention. Further, in all the drawings for explaining the embodiments, those having the same functions are designated by the same reference numerals, and the repeated description thereof will be omitted.

In FIG. 1, an image pickup type inspection apparatus includes a base 1
And an XY stage 2 that can move on the base 1 in the XY directions.
A pedestal 3 erected on the base 1, an optical microscope 4 movably mounted on the pedestal 3, a CCD camera 5 for picking up an observation image captured by the optical microscope 4, and an imaged observation The image processing apparatus 6 for image-processing the image and the video monitor 7 for displaying the image-processed observation image are roughly configured.

The base 1 is provided with an X-axis motor 8 and a Y-axis motor 9 for driving the XY stage 2 in the XY directions.
A sample (inspection object) W of spherical particles such as liquid crystal spacers mounted on the XY stage 2 is displaced in the XY directions. In this case, the XY directions are parallel to the inspection surface.
The gantry 3 is provided with a linear guide 10 for moving the vertically moving member 1
1 is provided so as to be vertically displaceable. A feed screw 13 that is rotationally driven by a Z-axis motor 12 is screwed into the vertical movement member 11, and the vertical movement position of the vertical movement member 11 is adjusted by the rotation of the feed screw 13.

An optical microscope 4 for magnifying and observing the sample W on the XY stage 2 is connected to the vertically moving member 11. The optical microscope 4 is provided with a revolver 15 having a plurality of objective lenses 14, and the revolver 15 variably sets the optical magnification by driving the objective lens 14 in divided rotation by a variable optical magnification motor 16 to change the objective lens 14. A CCD camera 5 is connected to the eyepiece side of the optical microscope 4, and the CCD camera 5 captures an enlarged observation image by the optical microscope 4. CC
An image processing device 6 is connected to the D camera 5. The image processing device 6 inputs an image signal (imaging information) output by the CCD camera 5, analyzes the image signal, and detects a defect.

A video monitor 7 is connected to the image processing apparatus 6, and the video monitor 7 visually displays a captured image of the sample W on the screen. Since the sample W is a transparent glass, the surface light source 17 is attached to the gantry 3 so as to be arranged on the opposite side of the sample W from the optical microscope 4, that is, on the lower side of the sample W.

The X-axis motor 8, the Y-axis motor 9, the Z-axis motor 12 and the variable optical magnification motor 16 are connected to a drive circuit 18 for driving them. The image processing device 6, the surface light source 17, and the drive circuit 18 are connected to the control device 19. The control device 19 causes the image processing device 6 to analyze the imaging information to determine the presence / absence of a defect, and controls the driving of the X-axis motor 8, the Y-axis motor 9, the Z-axis motor 12, and the variable optical magnification motor 16. When the CCD camera 5 takes an image of the sample W, the light intensity of the surface light source 17 is controlled.

Next, a method of detecting defects of fine particles by such an image pickup type inspection apparatus will be described. First, the control device 19
An operation command is issued to the variable optical magnification motor 16. This allows
The variable optical magnification motor 16 is driven, the revolver 15 is rotated, and the optical magnification of the optical microscope 4 is set to an optimum optical magnification according to the particle size of the sample W. Further, the control device 19 commands the X-axis motor 8 and the Y-axis motor 9 to perform a driving operation. As a result, the driving of the X-axis motor 8 and the Y-axis motor 9 is controlled, and the sample W is moved by the XY stage 2.
Scans and moves in the XY directions with respect to the optical microscope 4, and the sample W is positioned at the inspection position (imaging position).

Thereafter, the surface light source 17 irradiates the lower part of the sample W with light. In this case, the amount of transmitted light of the sample W is changed according to the optical magnification of the optical microscope 4. This is because the observation range becomes smaller as the optical magnification increases, so that the required amount of light cannot be obtained unless the amount of transmitted light is increased, and an appropriate contrast of the imaging target cannot be obtained.

Next, the sample W is imaged by the CCD camera 5. Then, the focus position of the optical microscope 4 is adjusted so that the density difference between the maximum density and the minimum density in the imaging screen becomes the maximum. That is, as shown in FIG. 2, since the in-focus position of the optical microscope 4 and the maximum position of the density difference coincide with each other,
The focus position is adjusted so that the density difference between the maximum density and the minimum density in the image pickup screen becomes maximum. The Z-axis motor 12 is driven to move and adjust the vertical moving member 11 in the vertical direction so that the difference between the maximum density and the minimum density in the imaging screen becomes maximum, and the height position of the optical microscope 4 is adjusted. .

After that, the image pickup device 6 analyzes the image pickup information from the CCD camera 5. That is, when the transmitted light of the sample W is observed by the optical microscope 4, parallel light is refracted inside the particles of the sample W according to the relationship of sin θ ₁ = nsin θ ₂ (Snell's law), and as shown in FIG. The part is dark and the central part is observed as a bright double coaxial circle. In addition, since foreign matter such as dust blocks light, the entire body is observed dark, so that the foreign matter is distinguished from particles such as liquid crystal spacers.

Further, the agglomeration state of particles is evaluated by measuring the area of each object in the image pickup screen after focus adjustment and dividing the area by a preset reference area to calculate the number of particles. That is, the outer peripheral area of the agglomerate is So, the reference area of one corresponding particle is Savo, and no = So / S
The agglomeration state of particles and the mixing state of foreign matter are determined by determining the number by avo. All the captured images are displayed on the video monitor 7.

As described above, in this embodiment, the optical microscope 4 is used.
Is focused on by the movement adjustment of the up-and-down moving member 11 by the Z-axis motor 12 based on the maximum density difference between the maximum density and the minimum density in the imaging screen.
The focus adjustment is easily performed without using an external detection means such as an optical displacement sensor. Therefore, it is possible to detect defects according to the particle diameter of the sample W with a simple device configuration.

As described above, the invention made by the present inventor is:
Although the present invention has been specifically described based on the embodiments, it goes without saying that the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention.
That is, as shown in FIG. 4, a robot 20 and a sample case 21 storing a plurality of samples W are arranged in the above-described imaging type inspection apparatus, and the robot 20 takes out an uninspected sample W from the sample case 21, This may be placed on the XY stage 2, or after the inspection of the sample W is completed, the inspected sample W may be taken out from the XY stage 2 and returned to the sample case 21. According to this, a plurality of samples W are provided in the sample case 21.
It is possible to continuously inspect a plurality of samples W simply by setting

[0023]

Advantageous effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows. According to the present invention, the focus position adjustment for adjusting the focus position of the image pickup means such that the density difference between the light source for transmitting light to the object to be inspected and the maximum density and the minimum density in the image pickup range of the image pickup means becomes maximum. Means, defect determining means for determining a defect based on imaging information of the inspection object, and a robot for supplying and discharging the inspection object,
Focusing at an optical magnification according to the particle size of the object to be inspected can be easily performed by a simple device without taking any other means, and the robot automatically supplies and discharges the object to be inspected. Therefore, a minute inspection object can be inspected with high accuracy and workability at low cost, variation in inspection accuracy due to difference in skill of workers can be reduced, and quantitative inspection can be performed.

[Brief description of drawings]

FIG. 1 is a perspective view of an imaging type inspection apparatus which is an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a defocus amount and an image pickup screen density difference of the image pickup inspection apparatus according to the embodiment of the present invention.

FIG. 3 is an observation diagram of light transmitted through a liquid crystal spacer according to an embodiment of the present invention.

FIG. 4 is a perspective view of an imaging type inspection apparatus which is another embodiment of the present invention.

[Explanation of symbols]

 1 base 2 XY stage 3 mount 4 optical microscope 5 CCD camera 6 image processing device 7 video monitor 8 X-axis motor 9 Y-axis motor 10 linear guide 11 vertical moving member 12 Z-axis motor 13 feed screw 14 objective lens 15 revolver 16 optics Variable magnification motor 17 Surface light source 18 Drive circuit 19 Controller 20 Robot 21 Sample case W sample

Claims (2)

[Claims] 1. An imaging means for optically enlarging and imaging an inspected object, an optical magnification varying means for changing an optical magnification of the imaging means, and a scanning movement of the inspected object with respect to the imaging means. Scanning movement means, a focus position adjusting means for adjusting a focus position of the image pickup means so that a density difference between a maximum density and a minimum density within an image pickup range of the image pickup means becomes maximum, and light for the object to be inspected. A light source for transmitting light, a means for changing the amount of light emitted from the light source to the inspected object, and a defect determining means for determining a defect based on the imaging information of the inspected object captured by the imaging means. An imaging type inspection device characterized by the above. 2. The imaging type inspection apparatus according to claim 1, further comprising a robot that supplies the object to be inspected to an image pickup position of the image pickup means and discharges the object to be inspected from the image pickup position. .