JP2002148200A - Particle measuring method and measuring device - Google Patents

Abstract

(57) [Problem] To provide a particle device capable of measuring particles adhering to a film surface in a normal factory environment and obtaining a measurement evaluation result in a short time. An illumination light source for irradiating a film surface from a direction perpendicular to an image capturing direction, a digital image data creation camera for capturing a particle shadow on the film surface on a stage movable in a horizontal direction and a focus direction, and A ROM memory unit 10c in which particle image data is input and stored, a stage control unit 10a for controlling a stage,
An image input control unit 10b for controlling input of particle image data, a ROM memory unit 10e storing a comparison determination program, and a determination result display unit 1 for displaying a determination result
0f, and a control / arithmetic computer 10 including a CPU 10d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for measuring the size and quantity of particles attached to the surface of a plastic film or the like.

[0002]

2. Description of the Related Art When a plastic film is used as a packaging material, the size and amount of particles (fine dust) adhering to the surface of a film may become a problem when the plastic film is used as a packaging material. . For example, if particles adhere to the hard disk that is the storage medium of the hard disk device in the electronics-related field, the magnetic head in operation will collide with the particles on the hard disk that is rotating at high speed and break, causing magnetic reading and reading. It becomes a problem that cannot be done. For this reason, the assembly of the hard disk drive, the manufacture of the disk, and the transportation are made so that fine dust is not mixed. Packaging materials used in such applications are also required to be free of fine dust. When used for the above applications in film production, packing, and transport, various measures have been taken to prevent the attachment of fine dust.However, the control of the attachment of fine dust is performed by particle measurement. Many.

Conventionally, measurement of particles adhering to a film is mainly performed by a liquid particle measurement method. In the liquid particle measurement method, the film surface is rinsed with a measurement medium, particles (fine dust) are mixed into the measurement medium, and the measurement medium is measured by a device called a liquid particle counter. The submerged particle counter outputs the amount of each particle (fine dust) as a measurement result. This value is converted to the measured value per unit area of the packaging material, and compared with the standard of the degree of dust adhesion for each application, and evaluated.

In this method of measuring particles in a liquid, it is necessary to apply ultrasonic vibration to separate the particles from the film surface. At this time, there is a problem that fine bubbles are generated and cannot be distinguished from particles, it takes time until the bubbles are settled, and the measurement result is not displayed in real time.

The measurement of particles is usually performed in a clean room environment. This is based on the idea of keeping the measurement accuracy by preventing fine dust other than those adhering to the film from entering the measurement environment. For this reason, a film sample for measuring the particle adhesion at each stage such as film production, packing, transportation, receiving, etc., is 10 cm in length and width.
The sample is cut at about m and collected, and the sample is taken into a clean room where a particle counter is installed.

As described above, the conventional particle measurement requires time and effort, and furthermore, the particle measurement requires specialized knowledge and experience, and usually takes about one to three days from the time of sampling. In this situation, quick measurement and evaluation cannot be performed.

[0007] In view of the above problems, an object of the present invention is to provide a particle device capable of measuring particles adhering to a film surface in a normal factory environment and obtaining a measurement evaluation result in a short time. And a method.

[0008]

Means for Solving the Problems According to the first aspect of the present invention, there is provided: (1) irradiating the surface of a film to be measured with irradiation light in a direction perpendicular to an image photographing direction. Meanwhile, the particles on the film surface are enlarged and photographed by the photographing means to obtain a particle image. (2) The obtained particle image is converted into digital data and input to the RAM memory unit of the control / calculation computer. (3) The comparison determination program stored in the ROM memory unit is started, the size and the number of the particles are measured from the particle image, and the pass / fail is determined by comparing with the standard value and recorded. (4) Display the size and number of the particles and the determination result. This is a particle measurement method characterized by measuring particles on the surface of a measurement object by the above procedure.

According to a second aspect of the present invention, there is provided an irradiation light source for irradiating a surface of a film to be measured from a direction perpendicular to an image photographing direction, and a film surface on a stage movable in a horizontal direction and a focal direction. A digital image data creation camera having an enlargement function for photographing the above particle shadow, and an R for inputting and storing the particle image data
An OM memory unit, a stage control unit for controlling a stage,
A control / arithmetic computer including an image input control unit that controls input of particle image data, a ROM memory unit that stores a comparison determination program, a determination result display unit that displays a determination result, and a CPU; A particle measuring device provided at least.

[0010] Further, the invention described in claim 3 is based on claim 2.
3. The particle measuring apparatus according to claim 2, wherein the irradiation light source and the stage capable of moving left and right are connected by a fixed arm and move in conjunction with each other.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a particle measurement device according to the present invention, and FIG. 2 is a perspective configuration diagram illustrating a configuration of a measurement unit for observing and photographing a particle image in a state where a film is wound around a cylindrical roll. It is.

The surface particle measuring apparatus for a plastic film or the like of the present invention comprises an optical microscope apparatus for enlarging and observing particles on the surface of a film (1), and a CCD camera (4) attached to an eyepiece of the optical microscope. Controlling the digital image data of the enlarged and photographed particle image by the image input control unit (1) of the computer (10)
According to the instruction 0a), the data is input to the RAM memory unit (10c).

From the input digital image data of the particles, utilizing the difference between the image density (brightness) of the film surface and the image density (brightness) of the particle image,
The particle image is separated and stored in the ROM memory (10
The comparison determination program stored in e) is started, and the size and quantity of the particles are detected. This detection result is evaluated by comparing it with a standard value.

In order to observe the film surface with an image, the optical microscope apparatus includes a left-right moving stage (21) for moving a CCD camera in a left-right (axial) direction on a stage (20) provided in parallel with the axis of a cylindrical roll. ), A focus moving stage (22) for moving in the focus (back and forth) direction, a left and right moving stage (21), and an irradiation light source (3).
It is connected in 2).

As described above, since the left and right moving stage (21) and the irradiation light source (3) are connected by the fixed arm (22), even when the CCD camera (4) is moved right and left, the photographing area of the camera is always maintained. Is irradiating, CCD
Even if the camera is moved, there is no need to adjust the position of the irradiation light source. In addition, the irradiation light source (3) includes a fixed arm (2).
3) It is provided on the vertical movement stage (24) at the tip, so that the position can be adjusted.

The dark-field illuminating device is arranged so as to illuminate the vicinity of the tangent of the cylindrical roll at a right angle from the axial direction of the optical microscope device passing through the center of the cylindrical roll (2) so that only fine particles float.

In this manner, fine particles (particles) of 1 [μm] or less can be observed at a magnification of about 500 times by observing the film in a dark field. The optical microscope is about 0.4 [μm] in bright field and 0.04 in dark field.
It is known that up to about [μm], observation can be made to the extent that it is possible to determine whether or not particles are present.

Since the field of view of a microscope having a magnification of about 500 times is small in an area of about 0.5 [mm] in length and width, a large area is measured by taking many measurement points and performing statistical processing. Need to be applied. For this purpose, in addition to the moving stage and the control mechanism, a cylindrical roll (2) for winding and fixing the film is provided, and a rotation mechanism for rotating the film and a rotation control mechanism are provided.

When a film to be measured is wound around the cylindrical roll (2), a thin and soft object such as a film is observed with a microscope, and when an image of the surface is taken, it is necessary to firmly fix the image on a flat surface. At the same time as possible
The microscope at the observation point, the illumination position, and the position of the film observation surface can be realized with good reproducibility.

Further, it also means that the dark-field illumination has a shape that is convenient for illuminating from a position almost right beside.
A wide range of film surfaces can be observed by the rotation mechanism of the cylindrical roll and each stage.

From the above characteristics, it is possible to incorporate the observation apparatus of the present invention on a film transport roll immediately before winding on a film production line to measure particles. Incorporating the observation device of the present invention into the plastic film production device, and sending a signal from the comparison unit of the observation device to the plastic film production device and comparing it with a preset standard value,
By providing a comparison data transmission unit for judging the quality based on the presence or absence of particles of the product, it is possible to obtain production management data.

The present invention will be further described with reference to specific numerical values based on one embodiment of the present invention.

Particles on the surface of the plastic film are measured by optically observing particles on the surface of the film and photographing an image by using a microscope (zoom lens manufactured by Hi-Rox Co.) of about 500 to 2000 times, and 300,000. A CCD camera having about 900,000 pixels to 900,000 pixels (manufactured by Hi-Rox) and an image input device (manufactured by Hi-Rox) for capturing image signals from the CCD camera are used. An equivalent product of another company may be used. Alternatively, a CCD camera may be attached to the eyepiece using a metal microscope of about 500 times. The image input device may be a personal computer equipped with an image input board.

Although a personal computer incorporating software for processing these captured images is used, these may be performed by a single personal computer. Further, a control device for issuing a command for controlling each stage may be realized by the single personal computer. Also,
The comparison unit that compares the measured data with the standard, the pass / fail judgment signal to the film manufacturing apparatus, and the manufacturing management data may be realized by one personal computer.

Each moving stage is realized by an ordinary linear rail and a positioning sensor, and an electric motor and an electric motor driver as power for linear movement. The cylindrical roll is
An electric motor and a driver are used for the rotation power, and positioning is performed using a rotation sensor. These controls are performed by the personal computer described above.

The dark-field illuminator uses a fiber type light guide to make the light source apparently smaller and to cut off extra illumination on the film surface. Particles adhering to the film, even small objects, protrude from the film surface. Therefore, the illumination from the lateral direction is scattered on the side surface of the particle and can be observed. At this time, it is important to illuminate the film surface so that the reflected light does not enter the microscope. When appropriate dark field illumination is applied, the film surface becomes a dark and sunk image as shown in FIG. 3A, and the film surface becomes invisible. Only the popping particles are observed as bright spots in the dark image. The size of this point is the size of the particle.

As a result of actual measurement, a film was wound around an aluminum cylinder having a diameter of 50 mm and fixed with a microscope of 500 times and light guide illumination, and observed.
m] can be observed.
The image range of 500 times is about 0.5 [mm] vertically and horizontally.
A plurality of particles of various sizes are observed therein.

As shown in FIG. 3, this image was captured as an 8-bit gray scale (256 gray scale) image and subjected to image processing. In the image processing, the image was binarized at the level of the 128th gradation among the 8-bit gradations to obtain a monochrome image (FIG. 3A). Here, the particle image (32) is inverted by black and white to appear as a black point (FIG. 3B). Since the black point has the number of pixels (33) proportional to the particle size, a histogram is created for each pixel number of each black point. About 0.5 [mm]
The size and quantity of particles in the range could be measured. The size and quantity of particles are expressed in each quantity per unit area of the film.

The moving stage is moved every time the image processing is completed because one image capturing range is about 0.5 [mm].
When the movement is measured 20 times in the horizontal direction × 20 times in the vertical direction, and a total of 400 times are measured, it is assumed that 1 [cm ² ] (unit area) of the film is measured. A histogram obtained by summing the measurement results of 400 times is the result to be obtained.

In the electronics-related field, the size and quantity of attached particles are specified as a number per unit area. For example, in plastic packaging materials for hard desks, particles having a size of 0.3 [μm] to 0.5 [μm] are 100 [particles / cm ² ] and particles having a size of 1.0 [μm] or more. It is specified to be 20 [pieces / cm ² or less]. If the particle measurement result of the observed film falls below this, it can be determined that the film is non-defective if the particle measurement result is lower than this.

By outputting this as an OK / NG signal, it can be applied as a signal for stopping the film manufacturing apparatus. Further, these results and judgments may be stored and used for product management data, inspection result tables, and the like.

[0032]

[Effect of the Invention] The present invention eliminates the need for special clean room equipment, and makes it easy for anyone to use it without any specialized knowledge and experience in measurement. In addition, since measurement can be performed in a short time and easily at a manufacturing site, the effect of the process improvement can be immediately confirmed at the manufacturing site, and it is possible to immediately determine in which process the mixing of fine dust has occurred. Therefore, the measurement data can be used as such management data as it is.

As an application other than the measurement of particles on the film surface, the present invention can be applied to the field of measuring particles similarly. For example, it can be used for surface particle measurement of a glass substrate of a color filter, a transfer film used for manufacturing a transfer film or a transfer type color filter, or a surface measurement of a transfer metal plate. It can be applied to other surface particle measurement.

[Brief description of the drawings]

FIG. 1 is a schematic view of the configuration of a particle measuring device according to the present invention.

FIG. 2 is a perspective configuration diagram of a particle image photographing unit of the present invention.

FIGS. 3A and 3B show a model for measuring the size of particles from a particle image, and FIG.
(B) is a plan view showing an image which has been binarized and inverted between black and white, and (c) is an enlarged image of a part (a) of (b).

[Description of Signs] 1 ... Film 2 ... Cylindrical roller 3 ... Irradiation light source 4 ... CCD camera 10 ... Control / calculation computer 10a ... Stage control unit 10b ... Image input control unit 10c ... RAM memory unit 10d ... CPU 10e ... ROM memory unit 10f ... Judgment result display section 20 ... Stage 21 ... Horizontal (axial) direction moving stage 22 ... Focus direction moving stage 23 ... Fixed arm 24 ... Irradiation light source up and down moving stage 31 ... Film surface part image 32 ... Particle image 33 ... Pixel

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Claims (3)

[Claims] (1) A particle image is obtained by enlarging and photographing particles on a film surface by a photographing means while irradiating irradiation light onto a film surface as a measurement object from a direction perpendicular to an image photographing direction. (2) The obtained particle image is converted into digital data and input to the RAM memory unit of the control / calculation computer. (3) The comparison determination program stored in the ROM memory unit is started, the size and the number of the particles are measured from the particle image, and the pass / fail is determined by comparing with the standard value and recorded. (4) Display the size and number of the particles and the determination result. A particle measurement method characterized by measuring particles on the surface of a measurement object by the above procedure. 2. An irradiation light source for irradiating a film surface to be measured from a direction perpendicular to an image photographing direction, and an image pickup device for photographing a particle shadow on the film surface on a stage movable in a horizontal direction and a focal direction. A digital image data creation camera with an enlargement function, a ROM memory unit for inputting and storing particle image data, a stage control unit for controlling a stage, an image input control unit for controlling input of particle image data, and a comparison determination program. A particle measuring device comprising at least a ROM memory unit that stores therein, a determination result display unit that displays a determination result, and a control / calculation computer including a CPU. 3. The particle measuring apparatus according to claim 2, wherein the irradiation light source and the stage movable left and right are connected by a fixed arm, and move in conjunction with each other.