JPH06118008A - Defect inspecting device for optical information recording medium - Google Patents

Abstract

PURPOSE:To provide a defect inspecting device for an optical information recording medium which allows defects to be detected with an ID area removed or distinguished by using a simple circuit structure. CONSTITUTION:A defect inspecting device comprises a light irradiating means to spirally radiate a light spot to the surface of an optical information recording medium in which an ID area and a data area are alternately formed, a rotating mechanism to rotate the optical information recording medium in opposition to a regularly rotating direction, a reflected light amount detecting means 20 to detect a light amount reflected from the optical information recording medium and an ID area detecting means to detect the position of the ID area from a detected reflected light amount signal. Also the device is provided with a binarizing means 22 to binarize the reflected light amount signal in accordance with a preset threshold value and an ID area removing defect detecting means 23 to detect defects from the reflected light amount signal at other positions than the ID area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium defect inspection apparatus for detecting a defect in an optical information recording medium such as a magneto-optical disk.

[0002]

2. Description of the Related Art An example of a conventional optical information recording medium defect inspection apparatus will be described with reference to FIG. The light emitted from the light source 1 passes through the polarization beam splitter 2 and is condensed by the objective lens 3 to be applied to the surface of the optical disc 4 as an optical information recording medium. Further, the reflected light from the optical disk 4 is reflected by the polarization beam splitter 2 and then guided to the light receiving element 6 via the cylindrical lens 5. As a result, the amplifier 7 calculates the sum of the amounts of reflected light, detects the reproduction signal (RF signal), and thus detects the defect 8 on the disk surface, and the amplifier 9 on one side calculates the difference in the amount of reflected light and outputs the focus error signal Fo. The focus control is performed by the detection.

In this case, the optical disc 4 is rotated and the defect detection system 10 is moved in the radial direction of the disc to scan the entire surface of the disc. When the defect 8 exists on the disk surface, the amount of reflected light decreases due to diffraction and scattering, so that the RF signal has a waveform as shown in FIG. The RF signal thus detected can be processed to detect the defect 8 as a defect signal as shown in FIG. 17B.

As a conventional example in which the defect 8 is taken out as a defect signal in this way, for example, Japanese Patent Laid-Open No. 2724/1990 is proposed.
There is one disclosed as an "optical disk defect inspection apparatus" in Japanese Patent Laid-Open No. 1-218906 and an "optical disk stamper inspection apparatus" in Japanese Patent Laid-Open No. 2-218906. In the former case, a signal obtained by binarizing the RF signal with a threshold value and RF
A defect signal is created using both the signal obtained by differentiating the signal. In the latter case, both the optical disk and the stamper are measured by the same defect detection system by using a correction plate when inspecting the stamper, and the defective portion of the stamper is taken out as a defect signal for inspection.

[0005]

According to such an inspection method, when the optical disk has only grooves (guide grooves) and no pits, the defect inspection can be performed as it is.
In the case of a sample in which the ID portion is formed by pits like a general optical disc, the RF signal also fluctuates in the pits of the ID portion similarly to the defect, and therefore the ID portion needs to be removed to prevent erroneous detection. FIG. 18 shows a magneto-optical disk 11
(For example, ISO130mmccs, ISO90mmccs
s etc.). In this case, the magneto-optical disk 11 has a groove 12 and a pit 13 for tracking formed in advance, and only the groove 12 is formed and a data portion 14 which is an area for writing data by the user after the disk is completed, and the groove Pit 1 besides 12
3 and the ID section 15 in which address information and the like are written. The magneto-optical disk 11 formed in this way
When light (including the disc master, stamper, etc.) is scanned with light, in addition to the fluctuation (decrease) of the RF signal due to the defect, the value of the RF signal also fluctuates in the ID section 15 as in the defect as described above. I will end up. For this reason, when detecting a defect on the magneto-optical disk 11, it is necessary to distinguish or remove the actual defect from the signal generated from the pit 13 of the ID section 15.

Conventionally, such defective portion and ID
In order to distinguish or remove the pit 13 of the part 15,
By performing tracking control and detecting a predetermined RF signal 16 generated from the pit 13 of the ID section 15 and generating a window signal 17 of the data section 14 as shown in FIG. Then, the defect signal 19 corresponding to the defect 18 is detected. However, for this purpose, in addition to the optical system as shown in FIG. 16, means for detecting a track error signal necessary for tracking control, signal processing means for performing tracking servo, and a convergent beam along the groove 12 are provided. Therefore, a means for moving the device, an ID signal decoding means for detecting the ID section 15 and the like are required, which may complicate the circuit and increase the cost.

[0007]

According to a first aspect of the present invention, there is provided a light irradiating means for irradiating a light spot in a spiral shape on a surface of an optical information recording medium in which an ID part and a data part are alternately formed, and A rotation mechanism for rotating the optical information recording medium in the direction opposite to the normal rotation direction, a reflected light amount detecting means for detecting the amount of reflected light from the optical information recording medium, and a position of the ID section from the detected reflected light amount signal. An ID section detecting means for detecting a defect, a binarizing means for binarizing the reflected light quantity signal based on a preset threshold value, and an ID for detecting a defect from the reflected light quantity signal at a position other than the ID section. And a part removal defect detecting means.

According to a second aspect of the present invention, a light irradiating means for irradiating a light spot in a spiral shape on the surface of the optical information recording medium in which the ID portion and the data portion are alternately formed, and the optical information recording medium are regularized. A rotation mechanism for rotating the optical information recording medium in the opposite direction, a reflected light amount detecting means for detecting the reflected light amount from the optical information recording medium, and an ID portion detection for detecting the position of the ID portion from the detected reflected light amount signal. Means, defect detection threshold value control means for switching a defect detection threshold value at the position of the ID portion, and binarization means for binarizing the reflected light amount signal based on the switched threshold value to detect a defect. Configured.

According to a third aspect of the present invention, in the second aspect of the present invention, the defect detection threshold value control means removes the high frequency component of the reflected light amount signal and the removed signal of the ID section. It comprises a gain amplifying means for amplifying to different gains at different positions.

According to a fourth aspect of the present invention, the light irradiating means for irradiating a light spot in a spiral shape on the surface of the optical information recording medium in which the ID portion and the data portion are alternately formed, and the optical information recording medium are regularly formed. A rotation mechanism that rotates in the opposite direction to the rotation direction, a reflected light amount detection unit that detects the amount of reflected light from the optical information recording medium, and a high frequency component removal unit that removes the high frequency component of the detected reflected light amount signal, Amplifying means for amplifying the removed signal, binarizing means for binarizing the reflected light amount signal with the amplified signal as a threshold value, and ID part detecting means for detecting the leading position of the ID part, It is constituted by an ID part removal defect detecting means for removing the head signal of the ID part from the binarized signal to detect a defect.

According to a fifth aspect of the present invention, the light irradiating means for irradiating a light spot in a spiral shape on the surface of the optical information recording medium on which the ID portion and the data portion are alternately formed, and the optical information recording medium are regularly arranged. A rotating mechanism for rotating the optical information recording medium in the opposite direction, a reflected light amount detecting means for detecting an amount of reflected light from the optical information recording medium, a high frequency component removing means for removing a high frequency component of the detected reflected light amount, and Amplifying means for amplifying the removed signal, ID section detecting means for detecting the head position of the ID section, and cutoff frequency switching for switching the cutoff frequency of the high frequency component removing section at the detected head position of the ID section. And a binarizing unit that binarizes the reflected light amount signal by using the amplified signal as a threshold and detects a defect.

According to the invention of claim 6, claims 1, 2 and
In the invention described in 4 or 5, the ID part detecting means is composed of a mirror mark detecting means for detecting the mirror mark and a pulse generating means for generating a pulse having a predetermined width from the detected mirror mark. .

According to a seventh aspect of the invention, in the sixth aspect of the invention, the mirror mark detecting means includes a high frequency component removing means for removing a high frequency component of the reflected light amount signal, and an amplifying means for amplifying the removed signal. And a binarizing means for binarizing the reflected light amount signal by using the amplified signal as a threshold value.

According to an eighth aspect of the invention, in the sixth aspect of the invention, the pulse generating means is a pulse width control signal for varying the pulse width according to the radial position information of the optical information recording medium or the type information of the optical information recording medium. A generation means is provided.

According to a ninth aspect of the invention, in the sixth aspect of the invention, the pulse generating means has a mirror mark length measuring means for measuring the length of the mirror mark and a pulse width depending on the length of the mirror mark. A variable pulse width changing means is provided.

According to a tenth aspect of the invention, the first and second aspects are
In the invention described in 2, 4, or 5, the ID part detecting means is
Binarizing means for binarizing the reflected light amount signal, pulse generating means for generating a predetermined pulse width from the falling signal of the binarized reflected light amount signal, and pulse generating means for the detected mirror mark. And a pulse width determining means for generating a pulse up to the output pulse end position.

According to an eleventh aspect of the invention, in the second aspect of the invention, the defect detection threshold value control means is provided with a threshold value switching means for switching the defect detection threshold value according to the optical information radial position information.

[0018]

According to the first aspect of the present invention, the ID section can be detected without the conventional tracking control means or ID section decoding means. Therefore, it is possible to provide a low-cost apparatus having a simple structure. It will be possible.

According to the second aspect of the present invention, it is possible to detect defects existing in the ID section as well.

According to the third aspect of the present invention, not only the fluctuation of the RF signal due to the track crossing can be eliminated, but also a continuous threshold signal can be generated even at the threshold switching position with a simple structure. It is possible to eliminate things that cause

According to the invention described in claims 4 and 5, the ID part can be detected without the conventional tracking control means and the decoding means of the ID part, and the defect can be detected with a much simpler structure. Becomes

According to the sixth aspect of the invention, the head of the ID part can be detected with a simple structure, so that a low-cost device can be provided.

According to the seventh aspect of the present invention, it becomes possible to stably detect the mirror mark even if the RF signal fluctuates due to the track crossing due to the eccentricity.

According to the invention described in claim 8, it is possible to inspect MCAV type discs and various discs.

In the inventions according to claims 9 and 10, the MCAV
It is possible to measure the type of disc and to automatically measure even if the type of disc changes.

According to the invention of claim 11, the partial R
It is possible to perform inspection on OM type disks.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. First, the outline of the overall configuration of the optical information recording medium defect inspection apparatus will be described with reference to FIGS. 1 and 2. This apparatus is provided with a light irradiation means (not shown) for spirally irradiating a light spot on the surface of an optical disk (not shown) as an optical information recording medium in which an ID section and a data section are alternately formed, and the optical disk is rotated normally. A rotation mechanism (not shown) for rotating in the opposite direction, and a reflected light amount detecting optical system 2 as a reflected light amount detecting means for detecting the amount of reflected light from the optical disk.
0, an ID part detection circuit 21 as an ID part detection means for detecting the position of the ID part from the detected reflected light amount signal (hereinafter referred to as an RF signal), and a preset threshold value e.
A binarization circuit 22 as a binarization means for binarizing the RF signal based on the above, and an ID section as an ID section removal defect detection section for detecting a defect from the RF signal at a position other than the ID section. Removal defect detection circuit 23 and defect detection storage circuit 24
And (corresponding to the invention of claim 1).
The optical disk, ID section, and data section referred to here are the optical disk 11, the ID section 15, and the ID section 15 in FIG.
It corresponds to the data section 14.

In such a configuration, the RF signal a output from the reflected light amount detection optical system 20 is processed by the ID detection circuit 21 to generate the ID position signal c, and the binarization circuit 22 is generated. Is binarized (threshold e) with RF
It becomes the signal b. And these two signals b and c are ID
By being sent to the part removal circuit 23, the defect 25 existing in the data part other than the ID part is extracted and the defect signal d is obtained. FIG. 2 shows the waveforms of these various signals.
Therefore, from the above, it is possible to extract the defect 25 only in the data portion without detecting the RF signal in the ID portion.

Next, the internal structure of the ID part detection circuit 21, which is a feature of this embodiment, will be described with reference to FIGS. First, FIG. 3 shows a first configuration example of the ID section detection circuit 21. This circuit includes a mirror mark detecting circuit 26 as a mirror mark detecting means for detecting a mirror mark,
A pulse generation circuit 2 as pulse generation means for generating a pulse having a predetermined width from the detected mirror mark.
And 7 (corresponding to the invention of claim 6). The mirror mark detection circuit 26 includes a low-pass filter (LPF) 28 as high-frequency component removing means for removing high-frequency components of the RF signal, and an amplifier as amplifying means for amplifying the removed signal. 29 and binarize the RF signal using the amplified signal as a threshold 2
It comprises a comparator 30 as a digitizing means (corresponding to the invention of claim 7).

In such a configuration, as shown in FIG. 4, the RF signal a in the case where tracking is not performed fluctuates by crossing the track. In order to detect the mirror mark 31 from the RF signal a, the signal obtained by removing the fluctuation of the RF signal a due to the pits, the mirror mark 31, etc. by the low pass filter 28 is amplified by the amplifier 29 to generate the mirror mark threshold signal h, Based on the mirror mark threshold value signal h, the RF signal a is binarized by the comparator 30 to generate the mirror mark signal g. In the case of the present embodiment, since the optical disc is rotated in the direction opposite to the normal rotation direction, the mirror mark 31 formed at the end of the ID section can be detected as the head position of the ID section. The pulse generation circuit 2 outputs the mirror mark signal g thus detected.
By sending it to 7, the ID position signal c having a pulse width of t ₁ corresponding to the length of the ID part can be generated.

5A and 5B show the configuration of the pulse generating circuit 27. First, in FIG.
A pulse width control signal generating circuit 32 as a pulse width control signal generating means for varying the pulse width according to the radial position information or the type information of the optical disk, and a pulse generator 33 are provided (corresponding to the invention of claim 8). ). Further, in FIG. 5B, a counter 34 as a mirror mark length measuring means for measuring the length of the mirror mark and a pulse width control as a pulse width varying means for varying the pulse width according to the length of the mirror mark. The signal generation circuit 35 and the pulse generator 36 are provided.

In such a configuration, in FIG. 5A, it is not necessary to measure only one type of CAV type disk, but in order to correspond to the length of ID different depending on the type, the pulse width control signal generation circuit In 32, the pulse width is changed by controlling the current supplied to the pulse generator 33 according to the product type. Then, a pulse generator (mono-multivibrator) 33 generates t ₁ pulse from the mirror mark signal g. In the case of MCAV disc,
Since the length of the ID becomes shorter toward the outer circumference of the disc, it is necessary to control such an ID. As shown in FIG.
In FIG. 5A, the pulse width is switched according to the external information (radius, product type), whereas in FIG. 5B, the length of the mirror mark is measured to generate the required pulse width. As shown in Table 1, the length of the ID part varies depending on the product type, but the ratio to the mirror mark length is always constant. Therefore, the counter 34 measures the mirror mark length and controls the generated pulse width accordingly. By doing so, it is possible to generate the necessary pulse width regardless of the product type and even in the case of MCAV.

[0033]

[Table 1]

Next, FIG. 6 shows a second configuration example of the ID section detection circuit 21. This circuit is a binarization circuit 37 as a binarization means for binarizing the reflected light amount signal, and a pulse generation means for generating a predetermined pulse width from the falling signal of the binarized RF signal b. Pulse generator (mono-multivibrator) 38, a rising edge detection circuit 39, and a flip-flop circuit 40 as pulse width determination means for generating a pulse from the detected mirror mark to the output pulse end position of the pulse generation means.
And a mirror mark detection circuit 26 and a falling edge detection circuit 41 (corresponding to the invention of claim 10).

In such a configuration, the RF signal a is set to 2
The binarizing circuit 37 binarizes the binarized signal b and inputs it to the pulse generator 38. By making the pulse width of the pulse generation circuit 38 wider than the pit interval, a repetitive trigger is input for each pit, so that the output pulse is ID.
It will be slightly wider than the section. By resetting the flip-flop circuit 40 at the falling edge of the mirror mark signal g and setting it at the falling edge of the signal, the required ID
The position signal c can be generated regardless of the type and CAV / MCAV. FIG. 7 shows the states of various timing signals.

Therefore, the conventional defect inspection method detects the ID portion by decoding the signal pattern for detecting the ID portion, and a tracking circuit, a decoding circuit and the like are required, whereas in the present embodiment, Since only the defect signal is detected from the RF signal that does not include the information of the ID portion using the mirror mark, it is possible to realize an inspection method with a simple configuration, thereby providing a low-cost device. be able to.

Next, a second embodiment of the present invention will be described with reference to FIGS.
A description will be given based on 0. The description of the same parts as those in the first embodiment (see FIG. 1) is omitted, and the same reference numerals are used for the same parts.

In the present apparatus of FIG. 8, the ID section detection circuit 2
In the subsequent stage of 1, the defect detection threshold value control circuit 42 as a defect detection threshold value control means for switching the defect detection threshold value at the position of the ID part, and the RF signal is binarized based on the switched threshold value to detect defects. Binarizing circuit 2 as a binarizing means for detecting
2 are provided (corresponding to the invention of claim 2). The defect detection threshold value control circuit 42 is shown in FIG.
As shown in FIG. 3, a low-pass filter 43 as high-frequency component removing means for removing high-frequency components of the RF signal and a gain amplifying circuit 44 as gain amplifying means for amplifying the removed signal to different gains at positions of the ID section. (Corresponding to the invention of claim 3). Further, a variable gain amplifier 45 as threshold switching means for switching the defect detection threshold according to the radial position information of the optical disk is connected to the subsequent stage of the defect detection threshold control circuit 42 (claim 1).
1 corresponds to the invention described in 1).

The principle of operation in such a configuration will be described. The ID part detection circuit 21 can generate the ID position signal c by using the mirror mark signal g as in the first embodiment. This ID position signal c is sent to the defect detection threshold value control circuit 42. In this defect detection threshold control circuit 42, two threshold voltages of the ID part and the data part may be prepared and switched by the analog SW, but here, a mechanism is required for preventing a momentary interruption of the signal during switching and false detection. Therefore, it has a structure that can be continuously switched. That is, the voltage generated by the low-pass filter 43 is generated by the variable gain amplifier 44 at the timing of the ID position signal c, which has a threshold voltage e having two thresholds of the ID part and the data part.
Further, by sending the threshold voltage e to the variable gain amplifier 45 and switching it at the disc radial position, it becomes possible to measure a partial ROM having a ROM portion in which information is previously written in pits in the data portion in the disc.
Note that FIG. 9 shows waveforms of various timing signals. Therefore, whereas the conventional defect inspection method removes the ID part, in the present embodiment, the defect inspection can be performed by changing the threshold values of the ID part and the data part.

Next, a third embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those of the first and second embodiments (see FIGS. 1 and 4) is omitted, and the same reference numerals are used for the same parts.

As shown in FIG. 11, the present apparatus is provided with a defect detection threshold signal generation circuit 46 and an ID part head position detection circuit 47 as an ID part detection means for detecting the head position of the ID part. In this case, as shown in FIG. 13, the defect detection threshold signal generation circuit 46 includes a low-pass filter 48 as high-frequency component removing means for removing high-frequency components of the RF signal and an amplifying means for amplifying the removed signal. It consists of an amplifier 49. The ID part head position detection circuit 47 for detecting the head position of the ID part includes a mirror mark detection circuit 26 and a pulse generator 50 (corresponding to the invention of claim 4).

Further, FIG. 15 shows a modification of the circuit of FIG. 13, in which the defect detection threshold signal generation circuit 46 and the ID are shown.
The detected ID is provided at the subsequent stage of the section head position detection circuit 47.
A signal switching circuit 51 is provided as a cutoff frequency switching means for switching the cutoff frequencies of the low-pass filters 48a and 48b at the head position of the section (corresponding to the invention of claim 5).

The principle of operation in such a configuration will be described. FIG. 12 shows signal waveforms at various portions of the circuit of FIG. 11, and FIG. 14 shows signal waveforms at various portions of FIGS. When the RF signal a is passed through the low-pass filter 48a, its cutoff frequency is 200μ.
When it is equivalent to m, it becomes like the j signal in FIG.
If the cutoff frequency is equivalent to 20 μm, the result of FIG.
It becomes like the k signal in (b). amplifier 49 for j and k signals
If the original RF signal is binarized into a defect signal by the l and m signals after passing through, the ID of the l signal in FIG.
Although the head of the part is erroneously detected as a defect, all defects of 200 μm or less can be detected. However, although the erroneous detection of the ID portion is eliminated by the m signal, the defect of 50 μm or more cannot be detected.

Therefore, in the circuit shown in FIG. 13, the pulse generation circuit (using a mono-multivibrator or the like) 50 generates the pulse ID section head signal f indicating the head of the ID section from the mirror mark signal c. Then, the defect signal d can be detected by removing the head of the erroneously detected ID portion in the l signal. Also, in the circuit of FIG.
By sending the ID head signal f to the signal switching circuit 51, the l and m signals are switched to change the threshold voltage e to the binarization circuit 22.
The defect signal d can be detected by binarizing only the head of the sending ID section with the m signal and binarizing the other with the l signal.

As described above, the defect detection threshold voltage e is made to substantially follow the RF signal a to detect only the defect 25 in which the RF signal fluctuates abruptly. If the fluctuating head of the ID part (actually, it is the last area of the ID part, but becomes the head position by rotating in the reverse direction) is erroneously detected, the part is removed by the ID part head signal f. , The defect signal d not including the ID portion can be obtained.

[0046]

According to the first aspect of the present invention, there is provided a light irradiating means for irradiating a light spot in a spiral shape on a surface of an optical information recording medium in which an ID portion and a data portion are alternately formed, and the optical information recording medium. A rotation mechanism for rotating the optical disc in the direction opposite to the normal rotation direction, a reflected light amount detecting means for detecting the amount of reflected light from the optical information recording medium, and an ID for detecting the position of the ID section from the detected reflected light amount signal. Part detection means, binarization means for binarizing the reflected light amount signal based on a preset threshold value, and ID part removal defect detection for detecting a defect from the reflected light amount signal at a position other than the ID part Since it is configured by the means, it becomes possible to detect the ID part without the conventional tracking control means and decoding means for the ID part, thereby providing a low-cost device with a simple structure. A.

According to a second aspect of the present invention, a light irradiating means for irradiating a light spot in a spiral shape on the surface of the optical information recording medium in which the ID part and the data part are alternately formed, and the optical information recording medium are regularly formed. A rotation mechanism for rotating the optical information recording medium in the opposite direction, a reflected light amount detecting means for detecting the reflected light amount from the optical information recording medium, and an ID portion detection for detecting the position of the ID portion from the detected reflected light amount signal. Means, defect detection threshold value control means for switching a defect detection threshold value at the position of the ID portion, and binarization means for binarizing the reflected light amount signal based on the switched threshold value to detect a defect. Since it is configured, it is possible to detect the defects existing in the ID portion as well.

According to a third aspect of the present invention, in the second aspect of the present invention, the defect detection threshold value control means removes the high frequency component of the reflected light amount signal and the removed signal of the ID section. Since it comprises gain amplifying means for amplifying different gains at different positions, it is possible not only to eliminate fluctuations in the RF signal due to track crossing, but also to generate a continuous threshold signal at the threshold switching position with a simple configuration. Thus, it is possible to eliminate the conventional false detection of defects.

According to a fourth aspect of the present invention, the light irradiating means for irradiating a light spot in a spiral shape on the surface of the optical information recording medium in which the ID portion and the data portion are alternately formed, and the optical information recording medium are regulated. A rotation mechanism that rotates in the opposite direction to the rotation direction, a reflected light amount detection unit that detects the amount of reflected light from the optical information recording medium, and a high frequency component removal unit that removes the high frequency component of the detected reflected light amount signal, Amplifying means for amplifying the removed signal, binarizing means for binarizing the reflected light amount signal with the amplified signal as a threshold value, and ID part detecting means for detecting the leading position of the ID part, Since it is constituted by the ID part removal defect detecting means for detecting the defect by removing the head signal of the ID part from the binarized signal, it is possible to eliminate the conventional tracking control means and decoding means for the ID part. It is possible to detect a part, in which it is possible to detect a defect in a more simple structure.

According to a fifth aspect of the present invention, the light irradiating means for irradiating a light spot in a spiral shape on the surface of the optical information recording medium in which the ID portion and the data portion are alternately formed, and the optical information recording medium are regulated. A rotating mechanism for rotating the optical information recording medium in the opposite direction, a reflected light amount detecting means for detecting an amount of reflected light from the optical information recording medium, a high frequency component removing means for removing a high frequency component of the detected reflected light amount, and Amplifying means for amplifying the removed signal, ID section detecting means for detecting the head position of the ID section, and cutoff frequency switching for switching the cutoff frequency of the high frequency component removing section at the detected head position of the ID section. The same effect as that of the invention according to claim 4 is obtained by the means and the binarizing means for binarizing the reflected light quantity signal by using the amplified signal as a threshold to detect a defect. It is those that can be.

The invention according to claim 6 is the invention as defined in claims 1, 2, and 4.
Alternatively, in the invention described in 5, the ID part detecting means is composed of a mirror mark detecting means for detecting the mirror mark and a pulse generating means for generating a pulse having a predetermined width from the detected mirror mark. , The head position of the ID part can be detected with a simple configuration, and thus a low-cost device can be provided.

According to a seventh aspect of the present invention, in the invention according to the sixth aspect, the mirror mark detecting means includes a high frequency component removing means for removing a high frequency component of the reflected light amount signal, and an amplifying means for amplifying the removed signal. Since the amplified signal is used as a threshold for binarizing the reflected light amount signal, the detection of the mirror mark can be stably performed even if the RF signal fluctuates across the track due to eccentricity. Is what you can do.

According to an eighth aspect of the invention, in the sixth aspect of the invention, the pulse generating means is a pulse width control signal for varying the pulse width according to the radial position information of the optical information recording medium or the type information of the optical information recording medium. Since the generation means is provided, MCAV type discs and various discs can be inspected.

According to a ninth aspect of the present invention, in the sixth aspect of the invention, the pulse generating means has a mirror mark length measuring means for measuring the length of the mirror mark and a pulse width depending on the length of the mirror mark. Since the variable pulse width changing means is provided, MCAV type discs can be measured, and even if the type of the disc is changed, it can be automatically measured.

The invention described in claim 10 is the same as in claim 1,
In the invention described in 4 or 5, the ID part detecting means is a binarizing means for binarizing the reflected light amount signal, and a pulse for generating a predetermined pulse width from the trailing signal of the binarized reflected light amount signal. Since the generating means and the pulse width determining means for generating the pulse from the detected mirror mark to the output pulse end position of the pulse generating means are provided, the same effect as that of the invention according to claim 9 is obtained. Is something that can be done.

According to an eleventh aspect of the present invention, in the second aspect of the present invention, the defect detection threshold value control means is provided with a threshold value switching means for switching the defect detection threshold value according to the optical information radial position information. It is also possible to inspect even a type of disc.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an optical information recording medium defect inspection apparatus that is a first embodiment of the present invention.

FIG. 2 is a timing chart showing various signal waveforms.

FIG. 3 is a block diagram showing a configuration of an ID unit detecting means.

FIG. 4 is a timing chart showing various signal waveforms.

FIG. 5 is a block diagram showing a configuration of a pulse generation circuit.

FIG. 6 is a block diagram showing a configuration of another ID unit detecting means.

FIG. 7 is a timing chart showing various signal waveforms.

FIG. 8 is a block diagram showing a configuration of an optical information recording medium defect inspection apparatus which is a second embodiment of the present invention.

FIG. 9 is a timing chart showing various signal waveforms.

FIG. 10 is a block diagram showing a configuration of defect detection threshold value control means.

FIG. 11 is a block diagram showing a configuration of an optical information recording medium defect inspection apparatus which is a third embodiment of the present invention.

FIG. 12 is a timing chart showing various signal waveforms.

FIG. 13 is a block diagram showing a first specific example of an optical information recording medium defect inspection apparatus.

FIG. 14 is a timing chart showing various signal waveforms.

FIG. 15 is a block diagram showing a second specific example of the optical information recording medium defect inspection apparatus.

FIG. 16 is a configuration diagram showing an example of a conventional optical information recording medium defect inspection apparatus.

FIG. 17 is a timing chart showing various signal waveforms.

FIG. 18 is a configuration diagram showing a surface shape of an optical information recording medium.

FIG. 19 is a timing chart showing various signal waveforms.

[Explanation of symbols]

 20 Reflection Light Amount Detection Means 21 ID Part Detection Means 22 Binarization Means 23 ID Part Removal Defect Detection Means 25 Defects 26 Mirror Mark Detection Means 27 Pulse Generation Means 28 High Frequency Component Removal Means 29 Amplification Means 30 Binarization Means 32 Pulse Width Control Signal generating means 34 Mirror mark length measuring means 35 Pulse width varying means 37 Binarizing means 38 Pulse generating means 40 Pulse width determining means 42 Defect detection threshold control means 43 High frequency component removing means 44 Gain amplifying means 45 Threshold switching means 47 ID Part detection means 48 High frequency component removal means 49 Amplification means 51 Cutoff frequency switching means

Claims (11)

[Claims] 1. A light irradiating means for irradiating a light spot in a spiral shape on a surface of an optical information recording medium in which an input information data section (hereinafter referred to as an ID section) and a data section are alternately formed, and the optical information. A rotation mechanism that rotates the recording medium in the opposite direction to the normal rotation direction, a reflected light amount detection unit that detects the amount of reflected light from the optical information recording medium, and a position of the ID section from the detected reflected light amount signal. The reflected light amount signal is set to 2 based on the ID part detecting means and the preset threshold value.
An optical information recording medium defect inspection apparatus comprising: binarizing means for binarizing; and ID portion removal defect detecting means for detecting a defect from the reflected light amount signal at a position other than the ID portion. 2. A light irradiating means for irradiating a light spot in a spiral shape on a surface of an optical information recording medium in which an ID portion and a data portion are alternately formed, and a normal rotation direction of the optical information recording medium, which is opposite to a normal rotation direction. Rotating mechanism for rotating the optical information recording medium, reflected light amount detecting means for detecting the amount of reflected light from the optical information recording medium, ID portion detecting means for detecting the position of the ID portion from the detected reflected light amount signal, and the ID portion. The defect detection threshold value control means for switching the defect detection threshold value at the position and the binarization means for binarizing the reflected light amount signal based on the switched threshold value to detect the defect. Optical information recording medium defect inspection apparatus. 3. The defect detection threshold value control means comprises high frequency component removing means for removing high frequency components of the reflected light amount signal, and gain amplifying means for amplifying the removed signal to different gains at the positions of the ID section. 3. The optical information recording medium defect inspection apparatus according to claim 2. 4. A light irradiating means for irradiating a light spot in a spiral shape on a surface of an optical information recording medium in which an ID portion and a data portion are alternately formed, and a normal rotation direction of the optical information recording medium, which is opposite to a normal rotation direction. A rotating mechanism for rotating the optical information recording medium, a reflected light amount detecting means for detecting a reflected light amount from the optical information recording medium, a high frequency component removing means for removing a high frequency component of the detected reflected light amount signal, and the removed signal. Amplifying means for amplifying, binarizing means for binarizing the reflected light amount signal using the amplified signal as a threshold value, ID part detecting means for detecting the head position of the ID part, and the binarizing An optical information recording medium defect inspecting device, comprising: an ID portion removal defect detecting means for removing a head signal of the ID portion from a signal to detect a defect. 5. A light irradiating means for irradiating a light spot spirally on the surface of an optical information recording medium in which an ID portion and a data portion are alternately formed, and a normal rotation direction of the optical information recording medium, which is opposite to a normal rotation direction. A rotating mechanism for rotating the optical information recording medium, a reflected light amount detecting means for detecting a reflected light amount from the optical information recording medium, a high frequency component removing means for removing a high frequency component of the detected reflected light amount, and an amplified signal. Amplification means for
An ID part detecting means for detecting the start position of the ID part, a cutoff frequency switching means for switching the cutoff frequency of the high frequency component removing means at the detected start position of the ID part, and the amplified signal as a threshold value. An optical information recording medium defect inspecting apparatus, comprising: a binarizing unit that binarizes the reflected light amount signal to detect a defect. 6. The ID section detecting means comprises mirror mark detecting means for detecting a mirror mark and pulse generating means for generating a pulse having a predetermined width from the detected mirror mark. Item 1. An optical information recording medium defect inspection apparatus according to item 1, 2, 4 or 5. 7. The mirror mark detecting means includes a high frequency component removing means for removing a high frequency component of the reflected light quantity signal, an amplifying means for amplifying the removed signal, and a reflected light quantity signal with the amplified signal as a threshold value. 7. The optical information recording medium defect inspection apparatus according to claim 6, comprising a binarizing means for binarizing. 8. The pulse generation means comprises pulse width control signal generation means for varying the pulse width according to radial position information of the optical information recording medium or product type information of the optical information recording medium. The optical information recording medium defect inspection apparatus described. 9. The pulse generating means comprises mirror mark length measuring means for measuring the length of the mirror mark, and pulse width varying means for varying the pulse width according to the length of the mirror mark. The optical information recording medium defect inspection apparatus according to claim 6. 10. The ID portion detecting means outputs the reflected light amount signal to 2
Binarizing means for binarizing, pulse generating means for generating a predetermined pulse width from the falling signal of the binarized reflected light amount signal, output pulse end position of the pulse generating means from the detected mirror mark Pulse width determining means for generating pulses up to
2. An optical information recording medium defect inspection apparatus according to 2, 4, or 5. 11. A defect inspection method for an optical information recording medium according to claim 2, wherein the defect detection threshold value control means comprises a threshold value switching means for switching a defect detection threshold value according to radial position information of the optical information recording medium. apparatus.