JPH0778897B2 - Optical information recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical information recording / reproducing apparatus for optically recording or reproducing information on a recording medium, and more particularly to an automatic information recording / reproducing optical beam tracking controlling apparatus. The present invention relates to improvement of a tracking control device.

[Prior Art] Conventionally, an optical head of an optical information recording / reproducing control device includes a light source such as a laser, a collimator lens for collimating a light flux from this light source, and a narrow light spot for recording on a record carrier as a small light spot. It is composed of an optical system such as an objective lens for irradiating the surface, a photodetector for receiving the light flux reflected by the recording surface, and the like.

At the time of recording, the recording surface of the record carrier is irradiated with a light beam which is modulated by predetermined information and focused by an objective lens, and information is recorded by causing a temperature rise or a chemical reaction on the recording surface. Also, during playback, it is reflected from the recording surface,
A light beam optically modulated by the recorded information is received by a photodetector, and the optical signal detected here is converted into an electric signal to obtain desired reproduction information.

Record carriers used for recording / reproducing such optical information include optical video discs, optical digital audio discs, and optical cards. The information to be recorded is, for example, in a concentric or spiral track in the case of a disc-shaped carrier (hereinafter referred to as an optical disc), and in a plurality of linear tracks arranged in parallel in the case of a card-shaped carrier. Each is recorded. Recording on this information track is based on unevenness, presence / absence of bits, changes in reflectance, changes in magnetization direction, and the like.

In order to record information accurately without causing trouble such as crossing between information tracks, it is necessary to control the irradiation position of the light spot in a direction perpendicular to the scanning direction of the information tracks (auto tracking , Hereinafter referred to as "AT"). Further, in order to irradiate the light spot as a stable minute spot despite the bending and mechanical error of the optical card, it is necessary to control in the direction vertical to the recording surface (autofocusing, hereinafter referred to as “AF”). ). Also, the above-mentioned AT and AF are required at the time of reproduction.

FIG. 5 is a block diagram showing the configuration of an information recording / reproducing apparatus for an optical card.

In the figure, the system controller 50 controls the motors 51 and 52 and the AT and AF control circuits 53 and 54 to control information recording / reproduction with respect to the optical card C.

The motor 51 reciprocates the optical card C in the direction of arrow a in the figure, whereby a light spot is emitted from the optical head 55 along the information track of the optical card C. Motor 52
Is for controlling the movement of the optical head 55 in the direction crossing the information track on the optical card C.

The optical head 55 includes a light source 55a made of a semiconductor laser and a collimator lens 5 for collimating the light flux from the light source 55a.
It has 5b, a beam splitter 55c, and an objective lens 55d, and irradiates the recording surface of the optical card C with a recording / reproducing light beam.

In addition, the optical head 55 includes a beam splitter 55e and a condenser lens 5
5f and 55g, photoelectric converters 55h and 55i, the optical beam reflected on the recording surface of the optical card C is converted into tracking signals and focusing signals by the photoelectric converters 55h and 55i, and the AT control circuit 53 and AF control are performed. Supply to circuit 54.

The AT control circuit 53 and the AF control circuit 54 move the objective lens 55d by moving a driving current to the tracking coil 55j and the focusing coil 55k of the optical head 55 to move the objective lens 55d.
Controls T and AF.

FIG. 6 is a block diagram of the AT control system centering on the configuration of the AT control circuit 53, and FIG. 7 is a waveform diagram for explaining the operation thereof.

In FIG. 6, the outputs Sa and Sb of the photoelectric conversion elements 1a and 1b of the photoelectric converter 55h are the tracking error amplifier 2
Then, the difference is amplified and extracted as a tracking error signal Sc. The tracking error signal Sc is appropriately phase-compensated by the phase compensation circuit 3 and input to the tracking servo circuit 4 to drive the tracking coil 55j.

The tracking error signal Sc is also input to the low pass filter (LPF) 5. LPF5 has an objective lens 55d
When it deviates from the neutral point of the AT actuator, the DC component Sd (7th DC) of the tracking error signal Sc is changed according to the distance.
(A) increases, only the DC component Sd is allowed to pass and is input to the head move comparator 6. The comparator 6 detects in which direction the AT actuator is deviated, and outputs a signal Se (7th
B) or Sf (FIG. 7C) is output to the head move controller 7, and the optical head drive signal Sg (FIG. 7D) is output. The signal Se is also used as a head direction signal, and is output to the system controller 50 as a command signal for moving the optical head 55 in a predetermined direction together with the signal Sg.

The outputs Sa and Sb of the photoelectric conversion elements 1a and 1b are added and amplified by the sum signal amplification circuit 8 and input to the comparator 9. The comparator 9 detects whether or not the light amount is within a predetermined range by comparing it with the comparison voltage Vr, and when the light amount is reduced, outputs a tracking abnormality detection signal Sn to the system controller 50 to notify the abnormality. The system controller 50 prevents overwriting by issuing a command to immediately stop recording.

[Problems to be Solved by the Invention] In such a conventional example, the AT is always detected with the same AT abnormality detection sensitivity.
Since an abnormality is detected, if the AT control is about to come off due to an external shock or a defect in the record carrier itself during recording, or if data is recorded with it out, the recorded data may not be replayed. There was a problem that important data was lost.

In view of the above-mentioned conventional problems, the present invention prevents the data from being lost by changing the detection sensitivity of the tracking control abnormality detecting means so as to be higher in recording and verifying than in reproducing. It is an object of the present invention to provide an optical information recording / reproducing device capable of recording information with high reliability in data reproduction.

[Means for Solving Problems] An object of the present invention is to record and verify information by irradiating a track-controlled light beam on a desired track among a plurality of tracks provided on a recording medium. In an optical information recording / reproducing device for reproducing, the tracking control abnormality detecting means for detecting abnormality in the tracking control and the detection sensitivity of the tracking control abnormality detecting means for recording and verifying are higher than those for reproducing. If the tracking control abnormality detecting means detects an abnormality in tracking control during recording and verifying, re-recording is performed on a track other than the track where the tracking control abnormality is detected. It is achieved by an optical information recording / reproducing apparatus characterized by the following.

[Embodiment] Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an auto-tracking control device in an optical information recording / reproducing device of the present invention, and FIG. 2 is a waveform diagram for explaining its operation.

In FIG. 1, the same parts as those in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted here.

In this embodiment, instead of the comparator 9 shown in FIG.
It has the same configuration as that of FIG. 6 except that an AT abnormality detection circuit 10 is provided and the sensitivity of this detection circuit 10 is switched by the switching signals CS _w and CS _v . Here, the switching signal CS _w is a signal outputted from the aforementioned system controller in order to switch the sensitivity during recording and reproduction, the switching signal CS _V for switching the sensitivity when verification after the recording (the Verify) Is a signal output from the system controller.

In such a configuration, the signal additionally amplified by the sum signal amplifier circuit 8 is within a predetermined light amount fluctuation range within the AT accuracy range during tracking, but the tracking is not performed due to an external impact or a defect on the record carrier. When it is about to come off or comes off, it exceeds the predetermined fluctuation range of the light amount. AT abnormality detecting circuit 10 monitors the output signal level of the sum signal amplifier circuit 8, and, AT abnormality detection sensitivity can be a switch by switching signal CS _w and CS _V, switching as shown in Figure 2 signal CS _v is AT abnormality detection sensitivity of the detection circuit 10 in accordance with (Fig. 2 a) and CS _w (FIG. 2 B) (Fig. 2 C) is switched. When a signal exceeding a predetermined level is input at each sensitivity, it is output to the system controller as an AT abnormality detection signal Sh. If the sensitivity during playback is L _A , the sensitivity during recording is L _B, and the sensitivity during verification is L _C , the respective sensitivities are set so that L _A <L _B <L _C. (Fig. 2C).

As described above, according to the present embodiment, by setting the sensitivity at the time of recording and verification higher than the sensitivity at the time of reproduction, a track defect such that AT control may be lost at the time of reproduction,
At the time of recording, although the AT control did not come off due to external shock etc., it was recorded while wobbling, so a track that could not be played normally during playback was found in advance at the time of recording or verification, and regular recording was not performed on that track, The reliability is ensured so that the recorded data can be reproduced by re-recording on the next track.

FIG. 3 is a block diagram showing another embodiment of the present invention.

The present embodiment has a detector 20 for detecting the moving speed of the objective lens 55d in the AT direction, and further has an AT abnormality detection unit 30 including the sum signal amplification circuit 8 and the AT abnormality detection circuit 10. Except for this, it has the same configuration as that of FIG.

The AT abnormality detection unit 30 includes a comparator 31, determination signal generators 32 and 33, and a changeover switch 34 in addition to the amplification circuit 8 and the detection circuit 10.
And 35, and an AND circuit 36.

The output of detector 20 is input to one of the comparator 31, the determination signal from the other via the switch 34 determines the signal generator 32 and 33 of the comparator 31 S _W and S _R is input. The change-over switch 34 is switch-controlled by the change-over signal CS _W , and inputs the signal S _W during recording and the signal S _R during reproduction into the comparator 31, respectively.

The output of the comparator 31 is input to the AND circuit 36 together with the output of the AT abnormality detection circuit 10, and the output thereof is input to the changeover switch 35. The output of the AT abnormality detection circuit 10 is directly input to the other input of the changeover switch 35. Changeover switch 35
Is switching control in switching signal CS _V, detected at the time of verification circuitry 1
The output of 0 is output to the system controller as the AT abnormality detection signal Sh at the time of recording and at the time of reproduction, respectively.

According to this structure, the switching signal CS _W
In a state of the switch 34 is shown so but becomes "1", the judgment signal S _W is input to the comparator 31, the signal Sm is the signal S _W
Compared for greater than or equal to. If it is larger, the comparison signal Sn is output, the AND circuit 36 is opened, and the output signal of the AT abnormality detection circuit 10 is passed. At this time, the changeover switch 35 turns the changeover signal CS
_{Since v} becomes "0", it is switched in the opposite direction to that shown, and the output of the AND circuit 36 is output as the AT abnormality detection signal Sh.

Since during reproduction switching signal CS _W and CS _V are both "0", the changeover switch 34 is switched to the direction opposite to the and the signal Sm and the signal S _R are compared by the comparator 31. Signal Sm is signal
When it is larger than S _R , the comparison signal Sn is output, and the output signal of the AT abnormality detection circuit 10 is output as the AT abnormality detection signal Sh via the AND circuit 36 and the changeover switch 35 as in the case of recording.

Since when verifying the switch signal CS _V becomes "1", the changeover switch 35 becomes the state shown in the figure, the output signal of the AT abnormality detecting circuit 10 is outputted as direct AT abnormality detection signal Sh.

As described above, according to the present embodiment, even if the AT abnormality detection circuit 10 outputs a detection signal during recording or reproduction, at the same time, if the moving speed of the objective lens is less than or equal to a predetermined value, AT abnormality is not detected, while , At the time of verification, the output of the detection circuit 10 is directly output as the AT anomaly detection signal Sh, so that the AT anomaly detection sensitivity is switched to be higher during verification than during recording and reproduction. .

Further, by setting the level of the judgment signal S _W and S _R so that S _W <S _R, the sensitivity at the time of recording is higher than the sensitivity at the time of reproduction. Therefore, it is possible to eliminate in advance a track that may not be normally reproduced at the time of reproduction at the time of highly sensitive recording and verification.

FIG. 4 is a block diagram showing still another embodiment of the present invention.

In this embodiment, a detector 20 for detecting the moving speed of the objective lens 55d in the AT direction and an AT abnormality detecting section 40 are provided, and the AT deviation is detected only by judging the moving speed of the objective lens. The structure is the same as that shown in FIG. 1 except that it is provided.

The AT abnormality detection unit 40 includes a comparator 41, a determination signal generator 42 and
43, a changeover switch 44, an AND circuit 45, and an OR circuit 46.

The output of the detector 20 is input to one of the comparators 41 and
The other side of 41 is provided with a decision signal generator 42 via a changeover switch 44.
And 43 input decision signals S _V and S _W. The change-over switch 44 is switch-controlled by the change-over signal CS _V , and inputs the signal S _V to the comparator 41 at the time of verification and the signal S _W at other times, respectively.

The output of the comparator 41 is supplied to the AND circuit 45, and the switching signal
Is gated and output to the system controller by the output signal of the OR circuit 36 for ORing the CS _W and CS _V.

With this configuration, when recording switching signal CS _W is "1", since the switching signal CS _V becomes "0", the changeover switch 44 becomes the opposite state and shown, the judgment signal S _W is the comparator 41
Is input, the signal Sm is compared whether the signal S _W is greater than. If it is larger, the comparison signal Sn is output to the AND circuit 45. Since the output of the OR circuit 46 is "1", the comparison signal Sn is output as the AT abnormality detection signal Sh.

When verification signal CS _V is "1", the signal CS _W is "0", the changeover switch 45 is in the state shown in the result judgment signal S _V is compared with the input signal Sm to the comparator 41, at the time of recording Similar to the case, the comparison signal Sn is output as the AT abnormality detection signal Sh.

During playback, switching signal CS _W and CS _V are both "0",
Since the AND circuit 45 is closed, the output of the comparator 41 is ignored.

As described above, according to the present embodiment, the levels of the determination signals S _V and S _W are set so that S _V <S _W , so that the recording time is longer than the reproducing time and the verification time is higher than the recording time. Tracks that have high sensitivity and may not be reproduced normally during reproduction can be eliminated in advance during recording or verification.

In the above description, the switching signals for recording / verifying / reproducing are supplied to the AT control system by two signal lines, but each switching signal may be serially supplied by one signal line. . Also, although the AT sensitivity is switched within the AT control system, the AT sensitivity is kept constant and the speed information of the objective lens is sent to the system controller.
The system controller may determine whether or not to accept the AT abnormality, and as a result, the sensitivity may be switched.

[Effects of the Invention] As described above, according to the present invention, the tracking control may be lost during reproduction by changing the detection sensitivity of the tracking control abnormality detecting means so that the detection sensitivity is higher during recording and during verification. It is possible to severely detect a defective track or a track on which information is recorded while wobbling although the tracking control is not lost due to an external impact or the like at the time of recording or at the time of verification. Therefore, by re-recording on a track other than the track in which the tracking is abnormal based on the detection, there is an effect that information recording with high reliability of data reproduction can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an optical information recording / reproducing apparatus according to the present invention, FIG. 2 is a waveform diagram for explaining its operation, and FIG. 3 is another embodiment of the present invention. 4 is a block diagram showing still another embodiment of the present invention, FIG. 5 is a block diagram showing the configuration of an information recording / reproducing apparatus for an optical card, and FIG. 6 is a conventional auto FIG. 7 is a block diagram showing the configuration of the tracking control device, and FIG. 7 is a waveform diagram for explaining the operation of FIG. 1a, 1b …… Photoelectric conversion element 8 …… Sum signal amplification circuit 10 …… AT abnormality detection circuit 20 …… Detector 30,40 …… AT abnormality detection unit 31,41 …… Comparator 50 …… System controller 53… … AT control circuit 55 …… Optical head 55d …… Objective lens C …… Optical card

Claims (1)

[Claims] 1. Recording and verifying of information by irradiating a desired light beam among a plurality of tracks provided on a recording medium with a tracking-controlled light beam.
In an optical information recording / reproducing apparatus for reproducing, the tracking control abnormality detecting means for detecting abnormality in the tracking control and the detection sensitivity of the tracking control abnormality detecting means are set to be higher in recording and verifying than in reproducing. When the tracking control abnormality detecting means detects an abnormality in the tracking control during recording and verifying, the recording sensitivity is changed, and re-recording is performed on a track other than the track in which the tracking control abnormality is detected. Characteristic optical information recording / reproducing device.