JPH1038545A - Surface inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface inspection device which can judge in a short time whether the surface of an object to be inspected is normal or abnormal. SOLUTION: A picture signal showing a one-dimensional picture of an object to be inspected is inputted repeatedly by a CCD line sensor 22, and the picture signal is preprocessed and corrected through shading, then it is converted into a digital signal. Further, the one-dimensional picture which is converted into a digital signal and shows a picture signal is converted into a binarized picture through a binarized picture conversion means 26, which is represented by two values, one and zero. Then, a clock signal having a specified clock cycle is generated by a clock signal generation means 28, and the clock pulse of the clock signal generated thereby is measured with a counter 27 as to obtain respective widths of the binarized picture obtained by the means 26 in which one and zero continue respectively. Further, the width obtained by the counter 27 is compared with a reference width by a judging means 29, thereby judging whether the surface of the object to be inspected in the one-dimensional picture is normal or abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection apparatus for inspecting the quality of a surface of an object.

[0002]

2. Description of the Related Art In order to avoid strong interference with a head for accessing a hard disk, a large number of scratches long in the rotation direction of the hard disk are actively formed on the surface of a hard disk used as a storage device of a computer. doing. The scratches are formed for such a purpose, and the width of the scratches and the interval between the scratches are controlled.

Conventionally, when inspecting such surface flaws, a visual inspection of the surface condition of the hard disk is carried out by placing a light source so as to reflect light well on the surface of the hard disk and observing the reflected light. I have.

[0004]

An automatic inspection instead of the visual inspection has been attempted. As a method of realizing the automatic inspection, a two-dimensional image of the surface of the hard disk is taken, and a scratch appearing on the two-dimensional image is taken. It is conceivable to obtain the width of the pattern and the interval between the scratches by calculation. However,
It is possible to adopt such an automatic inspection method when sampling a very small number of products from a large number of products for inspection. It is too time-consuming and impractical.

[0005] In view of the above circumstances, it is an object of the present invention to provide a surface inspection apparatus capable of performing an inspection of a surface of a subject in a short time when the above-described hard disk or the like is used as a subject.

[0006]

The principle of the surface inspection apparatus of the present invention which achieves the above object will be described. FIG. 1 is a principle block diagram of the surface inspection apparatus of the present invention. The image input means 11 is a time-series image signal in the main scanning direction, which represents a one-dimensional image of the surface of the subject relatively moving in the predetermined sub-scanning direction and which crosses the main scanning direction. Is a means for repeatedly inputting.

[0007] The image conversion means 12 is means for converting the one-dimensional image input by the image input means into a binary image represented by a binary value of a first value and a second value. The clock signal generation means 13 is a means for generating a clock signal having a predetermined clock cycle. The predetermined clock cycle is determined according to the resolution of the binary image and the resolution for measuring the width of the pattern shown in the image.

[0008] The counter 14 is a clock signal generating means 1
3. By counting the clock pulses of the clock signal generated in step 3, the width of the binary image obtained by the image conversion unit 12 where the first value is continuous and the width where the second value is continuous are obtained. is there. The determination means 15 includes a counter 14
Is a means for judging the quality of the surface of the subject appearing in the one-dimensional image based on the width obtained by (1).

In the case of the surface inspection apparatus of the present invention, the one-dimensional image is binarized, and the line width and the interval between the lines expressed on the binarized one-dimensional image are counted. It is not necessary to refer to the information of the one-dimensional image deviating from the one-dimensional image that is currently to be inspected, for example, on the surface of the subject, adjacent to the one-dimensional image. That is, without waiting for the image of the entire surface of the subject or an image of a wide area to be captured, the process for the pass / fail determination is completed only by a simple operation of counting clock pulses. Therefore, the inspection of the surface of the subject can be performed in a short time.

[0010]

Embodiments of the present invention will be described below. FIG. 2 is a block diagram showing the configuration of one embodiment of the surface inspection device of the present invention. FIGS. 3 to 5 have a plurality of grooves (scratches) on the surface using the surface inspection device shown in FIG. FIG. 3 is an explanatory diagram when inspecting the surface of a hard disk.

A hard disk 21 having a scratch 21a on its surface shown in FIG. 2 is rotated around the center of rotation of the hard disk 21 so that the CCD line sensor 22 captures a one-dimensional image of the hard disk 21 in the radial direction. Are located in When the light reflected on the surface of the hard disk 21 passes through an objective lens (not shown) and is detected by the CCD line sensor 22, an image signal representing a one-dimensional image of the hard disk 21 in the radial direction is preprocessed. Input to the means 23. This preprocessing means 23
Then, the noise of the image signal is removed, and the image signal from which the noise has been removed is input to the shading correction unit 24. The shading correction unit 24 corrects the image signal input from the preprocessing unit 23 based on a correction curve for correcting illumination unevenness on the surface of the hard disk 21, and the corrected image signal is input to the AD conversion circuit 25. . In the AD conversion circuit 25, the corrected image signal is converted into a digital signal, and the image signal converted into the digital signal is input to the binary image conversion means 26. The binary image conversion means 26 converts the image signal represented by the digital signal into
A binary image is obtained by binarizing with a predetermined threshold value.

FIG. 3 is a diagram showing a plurality of one-dimensional binary images on the hard disk surface obtained by the above-described method. Each one-dimensional image of the binary image shown in FIG.
, 7 and the pixels arranged in each one-dimensional image are represented by X =
Represented by 0, ..., 9. The hatched portion is a groove portion on the surface of the hard disk, and is '1' representing a binary image.
And the value of '1' out of the values of '0', and the white portion other than the hatched portion is a portion other than the groove on the surface of the hard disk and is represented by the value of '0'.

A binary image conversion means 26 as shown in FIG.
The image signal representing the binary image obtained by (see FIG. 1) is input to the counter 27. On the other hand, the clock signal generation means 28 generates a clock signal having a predetermined clock cycle, and this clock signal is also input to the counter. The counter 27 counts the number of clock pulses of the clock signal, thereby obtaining the width of continuous values of “1” and the width of continuous values of “0” of the image signal obtained by the binary image conversion means 26. .

FIG. 4 is an explanatory diagram for obtaining a width in which the values of “1” or “0” in the binary image shown in FIG. 3 are continuous. FIG.
(A) is a clock signal generated by the clock signal generation means 28 shown in FIG. 2, and the counter shown in FIG. 2 counts clock pulses of the clock signal. For example, for a one-dimensional image of Y = 0 in the binary image shown in FIG. 3 shown in FIG.
As shown in FIG. 4D, widths in which the value of “1” and the value of “0” continue are obtained, and Y = 3 in the binary image shown in FIG. The one-dimensional image is counted as shown in FIGS. 4 (f) and 4 (g), and the width where the value of “1” and the value of “0” continue are obtained.

Similarly, for the one-dimensional images of Y = 1, 2, 4, 5, 6, and 7, the value of “1” in each one-dimensional image,
The number of clock pulses corresponding to the width in which the value “0” continues is counted, and the width in which the value “1” and the value “0” continue is obtained. As shown in FIG. 4, when the number of each clock pulse corresponding to the continuous width of the value of “1” and the value of “0” of each one-dimensional image is counted by the counter 27 shown in FIG. 29, the width obtained by the counter 27 is compared with the reference width, and the quality of the surface of the subject appearing in the one-dimensional image is determined.

FIG. 5 shows the result of the determination means 29 shown in FIG.
FIG. 5 is a diagram showing a one-dimensional image in which a groove having a width outside the standard appears among the one-dimensional images representing the surface of the hard disk by comparing the width obtained in FIG. 4 with the standard width; Is a one-dimensional image in which a groove having a non-standard width has appeared. As shown in FIG. 5, when there is a groove having a width outside the standard in the one-dimensional image, the part of the hard disk surface represented by the one-dimensional image is determined to be abnormal.

As described above, in the surface inspection apparatus according to one embodiment of the present invention, a one-dimensional image representing the surface of a hard disk is
The groove of the hard disk is represented by a value of “1”, the portion other than the groove is converted into a binary image represented by a value of “0”, and the groove represented on the one-dimensional image converted into the binary image. The width and the distance between the grooves are counted, so the pass / fail judgment process is completed only by the simple calculation of clock pulse counting, using only the information of the one-dimensional image currently being inspected. I do. Therefore, the inspection of the surface of the hard disk can be performed in a short time.

In the above-described surface inspection apparatus according to one embodiment of the present invention, the quality of the surface is determined using a hard disk having a groove on the surface as the object, but the object is not limited to this. For example, the quality of a printed circuit board having a wiring pattern formed on the surface can be determined using the surface inspection apparatus of the present invention.

[0019]

As described above, according to the surface inspection apparatus of the present invention, the surface of the subject can be inspected in a short time.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of a surface inspection apparatus of the present invention.

FIG. 2 is a block diagram showing a configuration of an embodiment of the surface inspection apparatus of the present invention.

FIG. 3 is a diagram illustrating a hard disk surface as a binary image including a plurality of pixels arranged two-dimensionally.

FIG. 4 is an explanatory diagram for obtaining a width in which “1” values continue and a width in which “0” values continue in the binary image shown in FIG. 3;

FIG. 5 is a diagram showing a one-dimensional image of the one-dimensional image shown in FIG. 3 in which a groove having a width outside a standard appears.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Image input means 12 Image conversion means 13 Clock signal generation means 14 Counter 15 Judgment means 21 Hard disk 21a Groove 22 CCD line sensor 23 Preprocessing means 24 Shading correction means 25 AD conversion circuit 26 Binary image conversion means 27 Counter 28 Clock signal generation Means 29 Judgment means

Claims (1)

[Claims] 1. A time-series image signal representing a one-dimensional image of a subject surface moving relatively in a predetermined sub-scanning direction, which represents a one-dimensional image in the main scanning direction intersecting with the sub-scanning direction, is repeated. Image input means for inputting; image conversion means for converting a one-dimensional image input by the image input means into a binary image represented by a first value and a second value; and a predetermined clock A clock signal generating means for generating a clock signal having a period, and counting the clock pulses of the clock signal generated by the clock signal generating means, thereby obtaining the first image of the binary image obtained by the image converting means. A counter for calculating the width of the continuous value and the width of the continuous second value; and a determination means for determining the quality of the surface of the subject appearing in the one-dimensional image based on the width determined by the counter. Surface inspection apparatus characterized by comprising and.