Optics: measuring and testing – Inspection of flaws or impurities – Having predetermined light transmission regions
Patent
1990-01-23
1991-11-26
McGraw, Vincent P.
Optics: measuring and testing
Inspection of flaws or impurities
Having predetermined light transmission regions
356239, G01N 2188
Patent
active
050678124
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a defect inspecting apparatus detecting defects such as cracks in an optical recording area of an optical recording medium having a regularly disposed regular pattern.
2. Description of the Related Art
In optical recording media such as an optical card accessing data by means of a laser beam, malfunctions at the time of data access are prevented by carrying out an inspection as to whether defects such as cracks are present in the optical recording area or not before actually writing data on or using the optical recording area.
Hitherto, although the inspection of the optical recording area of this type has been carried out by means of optical instruments such as a microscope, there are problems in that the inspection requires much labor and accurate results can not be obtained.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a defect inspecting apparatus which solves the above described problems; that is the present invention easily and accurately carries out the inspection. In addition, the present invention does not require electrical image processing or image processing by means of software in order to eliminate the regular pattern.
The defect inspecting apparatus of the present invention which accomplishes the above object comprises an image forming optical system which enlarges an optical recording area of an optical recording medium having a regular pattern and an image processing part which converts the enlarged images obtained by the image-forming optical system into an image signal and detects the defect in the optical recording area by means of an image signal, and a space filter which removes the space frequency component of the regular pattern mounted on the image forming optical system.
More preferably, the space filter comprises an optical slit whose shape corresponds to the regular pattern.
According to the defect inspecting apparatus of the present invention, since the defect inspection can be carried out under the condition that the regular pattern present in the optical recording area is eliminated, the inspection can be easily and accurately executed.
Furthermore, since the regular pattern is optically eliminated, electrical image processing or image processing by means of software in order to eliminate the regular pattern are not required and thus the structure of the defect inspecting apparatus of the present invention can be simplified .
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a general view of a defect inspecting apparatus of one embodiment of the present invention;
FIG. 2 is a block diagram of the parts of a microscope;
FIG. 3 is a perspective view of an optical memory card;
FIG. 4 shows the principle concerning the function of a space filter;
FIGS. 5 (A) and (B) show the regular pattern present in an optical recording area and a space filter, respectively;
FIGS. 6 (A) and (B) show an optical recording area and an image-formed example obtained by the microscope, respectively;
FIG. 7 is a block diagram of an image processing part;
FIG. 8 shows an image signal;
FIGS. 9 (A), (B) and (C) show other embodiments of the space filter, respectively; and
FIGS. 10 (A), (B) and (C) show other further embodiments of the space filter, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENT
One embodiment of the present invention will be explained in detail with reference to the figures as follows.
FIGS. 1 to 8 explain one embodiment of the present invention.
As shown in FIG. 1, the defect inspecting apparatus of the present invention comprises a microscope 1 as an image forming optical system which enlarges an optical recording area 40 (FIG. 3) of an optical memory card 4, an optical recording medium, a camera 2 and an image processing part 3.
An X-Y autostage 5 which carries the optical memory card 4, a stage controller 6 controlling the X-Y autostage 5, a focusing device 7 and a light controller 8 are attached to the microscope 1 described above.
As shown in FIG. 2, the m
REFERENCES:
patent: 3981562 (1976-09-01), Anthon
patent: 4360269 (1982-11-01), Iwamoto et al.
patent: 4806774 (1989-02-01), Lin et al.
Izawa Shigeru
Kimura Fumio
Sugimura Koichi
Kabushiki Kaisha CSK
McGraw Vincent P.
LandOfFree
Systems for inspecting defects in an optical recording medium does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Systems for inspecting defects in an optical recording medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Systems for inspecting defects in an optical recording medium will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2383963