JPH0863771A - Optical recording/reproducing device - Google Patents

Abstract

PURPOSE: To provide timing for cleaning an optical head, an objective lens and a medium for every device by initial power, a device operation time and recording/reproducing quality at the time of manufacturing each optical disk device. CONSTITUTION: The medium 1 is irradiated by a light beam outgoing from a semiconductor laser 26 through the objective lens 21, and the light quantity of the reflected light is detected by a photodetector 24. The initial value of the reflected light quantity is measured when the device is manufactured to be held in a memory 11. The light quantity obtained while using is compared with a threshold value by a comparison circuit 13, and when the light quantity becomes the threshold value or below, an alarm urging the cleaning is issued. The threshold value is found by multiplying the initial value by a comparison coefficient (1 or below), and the comparison coefft. is made a higher value the more the device operation time is longer, and the more the recording/ reproducing quality is deteriorated largely. The recording/reproducing quality is obtained by a retry rate of recording or reproducing processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device, and more particularly to an optical disk device having a function of detecting in advance for each device that the recording / reproducing power on the recording film surface is lowered due to dust, laser deterioration, or the like. Regarding the device.

[0002]

2. Description of the Related Art Generally, an optical disk which is an exchangeable recording medium is inserted into an optical disk device in a case,
The shutter opens inside the optical disk device for recording / playback. Therefore, the optical disk device cannot be completely hermetically sealed, and invasion of dust from the outside cannot be avoided. As a result, the optical power on the surface of the recording film decreases, recording becomes impossible, and the retry rate during the recording / reproducing process inside the device increases.

Conventionally, for detecting dust on an optical disk recording / reproducing medium and an optical system, for example, Japanese Patent Application Laid-Open No. 61-1345.
As described in Japanese Patent Laid-Open No. 0 (Reference 1), the amount of reflected light from an optical disk recording / reproducing medium is detected, and whether the amount of reflected light is lower than a reference is compared to determine whether or not dust is present. An optical recording / reproducing device is known.

Further, there is disclosed an optical disk recording / reproducing apparatus provided with individual slice levels for detecting the reflected light amounts of information recording and information reproduction at different levels.
No. 173,629 (reference 2).

Further, in Japanese Patent Laid-Open No. 61-280045 (Reference 3), the focus of the objective lens of the optical head is adjusted to the position of the fixed light source by moving the optical head, and the light from the light source is reflected on the optical disk surface. Without receiving the light, the light is received by the photodetector via the objective lens of the optical head, the quarter-wave plate, the polarization beam splitter, etc., and the amount of received light is compared with the amount of light transmitted by the objective lens that has been measured in advance. An optical disk recording / reproducing apparatus is shown which detects the degree of dirt on the objective lens.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the prior art, in order to detect the dirt due to dust on the objective lens of the optical head and the surface of the medium to judge whether or not to clean, the fixed reference value and the detected amount of reflected light are used. However, a semiconductor laser that emits an optical laser has individual characteristics for each optical recording / reproducing apparatus, and if a fixed reference value is used for determination, dust will be detected excessively and excessively. Further, in Reference 3 above, the transmitted light of the objective lens measured in advance is used as a reference. However, even if the detected light amount varies depending on the recording characteristics of the optical disk medium to be recorded / reproduced, the inserted optical recording / reproduction is performed. Matching for each medium is not considered.

Further, in all of the above-mentioned documents 1 to 3, the usage situation of each optical recording / reproducing apparatus (use time and recording / reproducing characteristics (recording / reproducing quality) of the optical recording / reproducing apparatus and the optical recording / reproducing medium are taken into consideration. I haven't.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and for each recording / reproducing device, the initial power at the time of manufacture, the operating condition (usage condition) of the optical recording / reproducing device, and the inserted optical signal. By considering (adding) the recording / reproducing characteristics of the optical recording / reproducing device including the recording / reproducing medium, it is possible to judge the presence / absence of dirt due to dust or the like under a judgment condition unique to each optical recording / reproducing device, and thus perform periodic maintenance. It is an object of the present invention to provide an optical recording / reproducing apparatus that abolishes cleaning from the above and cleans only when cleaning is necessary.

Another object of the present invention is to report the timing of cleaning without excessive or excessive contamination of the optical recording / reproducing medium and the objective lens of the optical head, and to record with abnormal power. An object of the present invention is to provide an optical recording / reproducing apparatus which can ensure the reliability of the information recorded on the optical recording / reproducing medium and the reproduction information from the optical recording / reproducing medium by suppressing the information.

[0010]

To achieve the above object, the present invention is configured as follows in an optical recording / reproducing apparatus.

(1) A light amount detecting means for detecting the light amount of the light irradiated to the optical recording / reproducing medium through the optical system including the objective lens and reflected from the optical recording / reproducing medium, and the detected light amount. A comparing means for judging that the optical system or the optical recording / reproducing medium is contaminated when the detected light quantity becomes less than or equal to a threshold value, and the operating time of the optical recording / reproducing apparatus or recording / reproducing. An apparatus management means for managing quality and a threshold value changing means for increasing the threshold value as the use time becomes longer or the recording / reproducing quality becomes lower.

(2) In the above (1), the device management means uses the total light emission time of a light source such as a semiconductor laser as the device usage time, and the retry rate in the recording process or the reproduction process as the recording / reproduction quality. You can

(3) In the above (1) and (2), the initial value of the reflected light quantity is recorded and stored as the compared data (reference value) before the normal use of each optical recording / reproducing apparatus (for example, when the apparatus is manufactured). It should be noted that it is possible to use, as the threshold value, a value obtained by multiplying the reference value by a comparison coefficient according to the use time or recording / reproducing quality.

(4) In (3) above, the recording / reproducing area of the optical recording / reproducing medium is divided into a plurality of areas, a comparison coefficient is obtained for each area, and the threshold value is set for each recording / reproducing area according to the reference value and the comparison coefficient. The value can be obtained.

(5) In the above (1) to (4), when it is determined that the surface of the optical system (objective lens) or the optical recording / reproducing medium is dirty, a message to that effect is displayed or an alarm is issued. It can occur and prompt the user to clean or replace the medium or objective.

[0016]

The operation based on the above configuration will be described.

The light (laser light) from the optical head is reflected by the optical recording medium, and the reflected light is detected by the light amount detecting means (photodetector). The light amount detection means is configured to output a voltage proportional to the detected light amount of the reflected light, for example, and this voltage (light amount) is compared with a threshold value by the comparison means (comparison circuit). When the detected voltage (light amount) becomes equal to or less than the threshold value, it is determined that the objective lens of the optical system or the optical recording medium is contaminated by dust or the like.

In the present invention, the operating condition and recording / reproducing characteristics of the optical recording / reproducing apparatus are fed back to this threshold, that is, this threshold is the total operating time (operating time) of the optical recording / reproducing apparatus. Is set to a higher value by the control circuit. The total usage time of the above device is the total light emission time of the light source (laser light source), and it is considered that the emission light amount of the laser light source decreases as the total usage time increases. By raising the threshold value (before the actual recording or playback error occurs), the alarm can be issued earlier.

Further, this threshold value is controlled to be raised or lowered based on the monitoring result of the recording / reproducing characteristics (recording / reproducing quality) at the time of recording / reproducing of the apparatus or the medium, and the lower the recording / reproducing characteristics (quality) is. Since it is set to a high value, an alarm can be generated early before the quality is deteriorated.

Further, this threshold value is set in correspondence with the initial value of the reflected light amount obtained before the normal use such as when manufacturing the device. That is, this initial value is recorded and held in advance in a nonvolatile memory or the like in the device as a reference value, and the threshold value is a comparison coefficient according to the use time or recording / reproduction quality based on the reference value (initial value). Given as multiplied by (less than 1). This comparison coefficient has a higher value (a value closer to 1) as the usage time becomes longer and the recording / reproduction quality becomes lower.

As described above, the use time (total laser light emission time) and the actual recording / reproducing characteristics can be fed back to the threshold data to be compared, so that it is possible to accurately determine the timing of dirt and cleaning. The determination result is fetched by the control circuit and used for notifying the host computer, for notifying the display section outside the device, or for issuing an alarm.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram showing an embodiment of an optical disk device to which the present invention is applied.

The optical disk device shown in the figure has an optical disk medium 1 having a recording film 2, a spindle motor 3 for rotationally driving the optical disk medium, an optical head 4 for writing and reproducing information on the optical disk medium 1, and a purpose. It is composed of a voice coil motor 5 for positioning the optical head 4 at a position, and various control systems including a main control circuit 6. The various control systems include a positioning control system that functions under the main control system, an information recording system, an information reproducing system, and a reflected light amount detection system.

The positioning control system for the optical head 4 includes a voice coil motor 5 for positioning the optical head 4 at a target position.
And a positioning control circuit 18 that controls the position of the voice coil motor 5 based on the movement amount information 31 from the main control circuit 6.

The information recording system synchronizes the recording data 33 with the clock 42 and converts the recording data into recording code data 34 of a run length limited code sequence such as 2-7 modulation code, and the recording code data. The laser driver circuit 16 transmits 34 to the semiconductor laser element 26 as a recording pulse 35.

The information reproducing system amplifies the reproduction output 36 detected by the detector 24 in the optical head 4 to obtain a reproduction code (reproduction signal) 37 having an analog level proportional to the amount of light, and the direct current amplifier 14. The reproduction control circuit 15 is composed of a demodulation circuit which synchronizes the reproduction code with the clock 42 and performs an operation reverse to the encoding operation at the time of recording. The reproduction control circuit 15 transmits the address information 41 and the reproduction data 38 to the main control circuit.

Next, the reflected light amount detection system will be described. The reflected light amount detection system converts the reproduction output 36 into digitized data 39 that the main control circuit 6 can handle.
The converter 12, the non-volatile memory 11 in which the data 43 to be compared are recorded, and the comparison circuit 1 for comparing the both
3, the comparison result 40 is transmitted to the main control circuit 6. The A / D converter 12 converts the analog level of the reproduction code 37, which is proportional to the light quantity, into digital data representing the light quantity. Although these are drawn separately from the main control circuit 6, if the main control circuit 6 is a microcomputer including an A / D converter or the like, it can be considered that the main control circuit 6 is included in the microcomputer.

Now, an embodiment for detecting a decrease in the amount of reflected light will be described below.

The light beam 25 emitted from the semiconductor laser 26 reaches the galvanometer mirror 22 through the optical system, and the light beam deflected by the galvanometer mirror 22 is narrowed down by the objective lens (laser emitting lens) 21 and the recording film 2 is recorded. Irradiated on. FIG. 1 shows the most general optical head, and the present invention is not limited to the optical head shown in FIG. In FIG. 1, parts not related to the invention are simplified or omitted for the sake of simplicity. Further, the present invention is not limited to the write-once optical disc device, but can be applied to a rewritable optical disc device and a phase change optical disc device. The write-once optical disc device will be described below.

The light reflected on the recording film 2 returns to the inside of the optical head through the route opposite to the above. The light is separated from the incident light by the beam splitter 23 and is narrowed down by the lens,
The photodetector 24 is irradiated. Although the drawing shows the case where there is one photodetector 24 that receives the reflected light, the photodetector is originally provided for each signal for performing automatic focus control / tracking control and each data reproduction signal. The reproduction output 36 is a signal proportional to the total amount of light received by the photodetector 24, and is the same as the information reproduction signal, but a separate photodetector may be provided to receive the amount of reflected light, or the automatic focus control signal. Alternatively, it can be extracted from the tracking signal.

Further, in the case of an optical disc device, the laser emission light amount at the time of recording information and the emission light amount at the time of reproducing information are different from each other.
When recording information, the amount of reflected light differs depending on the shape of the optical pulse to be recorded. On the other hand, the amount of emitted light at the time of reproducing information is smaller and more constant than that at the time of recording information, so it is easier to know the state of dust by monitoring the amount of reflected light at the time of reproducing information.

Since the return light at the time of reproducing information is detected by the photodetector 24 as described above, when dust such as dust or dirt is deposited on the surface of the optical disk medium 1 or the surface of the objective lens 21, the reproduction is performed. It appears as a phenomenon that the output 36 drops.

The main control circuit 6 outputs the reproduction output to the DC amplifier 1
The digital data 39 of the reproduction code 37 amplified in 4 can be taken in, and a decrease in the amount of reflected light can be detected. In the case of a write-once type optical disc, when data exists on the recording film 3, the amount of reflected light is lower than the amount of reflected light in a non-recorded area of data. Therefore, when monitoring the dust condition, an optical head is used by using a positioning control system. It is easier to position 4 in the non-recorded area.

Next, the sequence of this embodiment will be described.

The reference value of the reflected light quantity is recorded inside the non-volatile memory 11 at the time of shipment of the apparatus. The recorded reference value is the digital data (the A / D converter 12 of the reflected light quantity of the non-recorded area at the time of shipment). Output 39) is also acceptable. The optical disk device performs a positioning operation in the non-recorded area according to an instruction from the main control circuit 6 when the optical disk medium 1 is inserted or is not accessed by the host computer, and the amount of reproduction light emitted from the non-recorded area is changed. The return light 36 is detected. As a result, the amplified return light digital data 39 is obtained and compared with the reference value in the nonvolatile memory inside the comparison circuit 13. The comparison circuit 13 is not special, and is configured to transmit the comparison result 40 to the main control circuit 6 when it becomes 80% or less of the reference value, for example.
In this case, when it becomes 80% or less of the reference value, the main control circuit 6 issues a warning to the display section 8 of the optical disk device, prepares a flag and the like inside, and issues a recording / reproducing command from the host computer. warning message or the like when the (SCSI: S mall C omputer
UnitA in S ystem I nterface
(ttention, etc.) is returned.

The amount of laser light emitted from the optical disk device differs slightly depending on the device. Further, the reflectance of the recording film surface of the optical disc medium 1 used when measuring the amount of reflected light at the time of shipment of the device also slightly changes. The fluctuation of the medium can be suppressed by using a specific reference medium when measuring the reflected light amount. Although the laser emission light amount for each device can be adjusted to some extent, if the reflected light amount is measured and recorded for each device by using the memory circuit 11, the decrease in the reflected light amount suitable for each device will be reduced. Can be detected.

Next, a description will be given of an embodiment for changing the threshold level for detecting a decrease in the amount of reflected light when the optical disk device is operating.

The power of the semiconductor laser 26 inside the optical disk device may decrease. Although this is related to the life of the device, the amount of emitted light seems to decrease (laser power decreases) as the emission time of the semiconductor laser 26 increases. By grasping the operating status of the semiconductor laser 26 and feeding it back to the threshold value for detecting the decrease in the amount of reflected light, a more appropriate cleaning trigger or replacement trigger can be obtained, and a failure in recording / reproduction can be prevented beforehand. . The semiconductor laser 26 is switched by the main control circuit 6, which normally emits the semiconductor laser 26 when the optical disk medium 1 is inserted and drives the automatic focus control circuit to focus the light spot on the recording film 2. Narrow to the top. Then, the tracking servo is applied by the tracking control circuit. In FIG. 1, the autofocus control circuit and the tracking control circuit are omitted. That is, the main control circuit 6 can recognize the light emission time of the semiconductor laser 26. This light emission time is determined by the main control circuit 6
Internal non-volatile memory or external non-volatile memory 1
Record to 1 and add sequentially. As shown in FIG. 2, this total light emission time is divided into several ranks, and the comparison coefficient to be compared with the reference value inside the memory 11 is switched for each rank.

Further, in order to reflect the recording / reproducing characteristics of the actual optical disk device on the threshold value for detecting the decrease in the amount of reflected light, the number of processing times when the recording and reproducing processing is executed after a certain optical disk medium is inserted, The number of internal retries is recorded in the nonvolatile memory inside the main control circuit 6 or the external nonvolatile memory 11. FIG. 3 shows an example in which the comparison coefficient to be compared with the reference value in the memory 11 is switched depending on the ratio of the number of blocks of the reproduction process and the number of retry blocks when the reproduction process is executed. The main control circuit 6 refers to this table and switches the comparison coefficient for each rank. Further, since the recording / reproducing area width of the optical disc medium 1 is about 3 to 6 cm, only a specific area may be soiled. Therefore, the retry ratio is detected for each recording / playback area,
If the comparison coefficient is switched for each area,
More reliable detection is possible. FIG. 4 shows an example in which the comparison coefficient to be compared with the reference value in the memory 11 is switched according to the ratio of the number of blocks of the recording process when the recording process is executed and the number of retry blocks when the recording process is executed.

Although the disk device of the above embodiment has both the recording function and the reproducing function, it may be a device having only one of the functions.

According to the above embodiment, it is possible to detect the fact that the optical disk device cannot normally perform the recording / reproducing, and to secure the reliability of the recording / reproducing information. Also, cleaning can be abolished from regular maintenance, and an opportunity can be provided only when cleaning becomes necessary. Further, since the trigger can be reported according to the operating status of the device and its quality, it is possible to optimize the report without being over- or under-reported.

[0043]

As described above in detail, according to the present invention, when it is determined that there is dirt due to dust or the like when the detected light quantity of the reflected light is less than or equal to the threshold value, Since a means for changing this threshold value according to the usage time and the recording / reproducing quality is provided, this threshold value is set to a higher value as the operating time of the device becomes longer and the recording / reproducing quality deteriorates. It is possible to obtain an effect that the dirt of each device can be accurately detected including the usage status of each device and the recording / reproducing quality.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical disk device applied to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conversion table that determines a comparison coefficient from a total light emission time.

FIG. 3 is a configuration diagram of a conversion table that determines a comparison coefficient from a reproduction processing retry rate.

FIG. 4 is a configuration diagram of a conversion table that determines a comparison coefficient from a recording processing retry rate.

[Explanation of symbols]

 1 optical disk recording / reproducing medium 2 recording film 3 spindle motor 4 optical head 5 voice coil motor 6 main control circuit (microcomputer) 7 host computer 8 display section 11 non-volatile memory 12 A / D converter 13 comparison circuit 14 direct current amplifier 15 reproduction control circuit 16 laser drive circuit 17 recording control circuit 18 positioning control circuit 19 clock circuit 21 objective lens 22 galvanometer mirror 23 beam splitter 24 photodetector (photodetector) 25 lens 26 semiconductor laser 31 moving amount information 32 moving current 33 recording data 34 recording code data 35 recording pulse 36 reproduction output 37 reproduction code 38 reproduction data 39 digital data 40 comparison result 41 address 42 clock 43 comparison data

Claims (1)

[Claims] 1. A light amount detecting means for detecting a light amount of light irradiated to an optical recording / reproducing medium and reflected from the optical recording / reproducing medium through an optical system including an objective lens, and the detected light amount as a threshold value. And a judgment means for judging that the optical system or the optical recording / reproducing medium is contaminated when the detected light quantity becomes equal to or less than a threshold value, and the operating time of the optical recording / reproducing apparatus or the recording / reproducing quality. An optical recording / reproducing apparatus comprising: a device managing unit that manages the threshold value; and a threshold value changing unit that increases the threshold value as the use time becomes longer or the recording / reproducing quality deteriorates.