JPH03116438A - Information recorder - Google Patents

Abstract

PURPOSE:To surely detect all double recording states and to prevent information which is already recorded from being destroyed by detecting the level of reflected light of a recording beam which is reflected by an optical recording medium and also detecting whether or not there is a recorded pit between a recording light beam and a recording light beam at the same time. CONSTITUTION:The device is provided with a 1st detecting means 27 which detects the reflected light of the recording light beam from the optical recording medium 11 being lower than a specific level a 2nd detecting means 26 which detects the recorded pit recorded with the reflected light of the recording light beam from the optical recording medium 11. Further, the device is provided with counting means 33 and 30 which count the detection result of the 1st detecting means 27 and the detection result of the 2nd detecting means 26 during recording and stop control means 34 and 31 which stop the emission of the recording light beam by a light output means 16 when either counted value reaches a specific value 35 or 32. Consequently, accidental double recording is surely detected during recording to prevent the information with is already recorded from being destroyed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to an information recording device for recording information on an optical recording medium such as an optical disk.

(Prior Art) Conventionally, in an information recording device such as an optical disk device that optically records or reproduces information on an optical recording medium such as a write-once optical disk, a semiconductor laser oscillator (light output means) is used as a light source. While the information on the optical disk is read using a relatively small continuous optical output from the optical disk, information is recorded on the optical disk in the form of pits using a relatively large and intermittent optical output that changes over a predetermined value. There is.

Therefore, if an optical disc is irradiated with a light output that exceeds the above-mentioned predetermined value, it may not be intended for recording (but it may write undefined information on the optical disc and destroy information that has already been recorded). It turns out.

For example, Japanese Patent Application No. 57-40592 discloses a method for preventing the destruction of information due to such double recording. This method detects double recording by detecting whether recorded pits exist between recording pulses during recording.

(Problem to be Solved by the Invention) However, in the conventional method described above, when recording is performed as in 1, 2, 3, 4, 5 as shown in FIG. Unable to detect double recording (4, 5). Furthermore, with the method of detecting only the reflected light of the recording pulse, it is not possible to detect the double recording state of the first track when recording is performed as shown in 1.2, 3.4', and 5' in Figure 2. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an extremely reliable information recording device that can reliably detect double recording in the unlikely event of recording and prevent the recorded information from being destroyed. shall be.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides pitting information on an optical recording medium by emitting a pulsed recording light beam from a light output means to the optical recording medium. In the information recording apparatus for recording in the form of: a first detection means for detecting that reflected light of the recording light beam from the optical recording medium is below a predetermined level;
a second detection means for detecting recorded pits that have already been recorded by the reflected light of the recording light beam from the optical recording medium; and a detection result of the first detection means and the detection result of the second detection means during the recording operation. A counting means for counting each detection result, and a stop control means for stopping the emission of the recording light beam from the light output means when one of the counted values of the counting means reaches a predetermined value. Equipped with

(Function) By detecting the magnitude of the reflected light of the recording light beam from the optical recording medium, and simultaneously detecting whether or not there are recorded pits between the recording light beams. , all double recording states can be reliably detected.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an optical disk device as an information recording device according to the present invention. In the figure, an optical disk (optical recording medium) 11 is mounted on the surface of a circular substrate made of glass or plastic, for example.
It is made of a donut-shaped metal coating layer such as tellurium or bismuth.

The optical disc 11 is rotated by a spindle motor 12. The spindle motor 12 is configured to have its rotation start, stop, rotation speed, etc. controlled by a motor control circuit 14 that operates in response to a control signal from a control circuit (control means) 13.

The control circuit 13 is composed of, for example, a microprocessor, and in addition to controlling the rotation of the spindle motor 12,
It is in charge of various controls described later.

An optical head 15 is provided below the optical disc 11 . The optical head 15 records or reproduces information on the optical disc 11, and includes a semiconductor laser oscillator (light output means) 16, a collimator lens 17, a polarizing beam splitter 18, an objective lens 19, a condenser lens 20. and photodetectors 21, 22, etc.

The optical head 15 is disposed to be movable in the radial direction of the optical disc 11 by a moving mechanism (not shown) constituted by, for example, a linear motor, and is configured to record or reproduce an object according to instructions from the control circuit 13. The vehicle is moved to the target track.

The semiconductor laser oscillator 16 generates a diverging laser beam (light beam) according to the drive signal S1 from the optical output control circuit 24, and when recording information on the recording film of the optical disc 11, it A strong laser beam whose light intensity is modulated according to the information is generated, and when information is read and reproduced from the recording film of the optical disk 11, a weak laser beam having a constant light intensity is generated. .

The diverging laser beam generated by the semiconductor laser oscillator 16 is converted into a parallel beam by the collimator lens 17 and guided to the polarizing beam splitter 18 . The laser beam guided to the polarizing beam splitter 18 passes through the polarizing beam splitter 18 and enters the objective lens 19.
The objective lens 19 focuses the light onto the recording film of the optical disc 11 .

The objective lens 19 is supported by a lens actuator 23 serving as a lens driving means so as to be movable in the forward axis direction. By being moved in the optical axis direction by a servo signal from a focus servo circuit (not shown), the focused laser beam that has passed through the objective lens 19 is emitted onto the surface of the recording film of the optical disk 11, and the minimum beam spot is is formed on the surface of the recording film of the optical disc 11. In this state, objective lens 1
One is in focus.

Furthermore, one objective lens is also movable in a direction perpendicular to the optical axis, and the objective lens 19 is moved in a direction perpendicular to the optical axis by a servo signal from a tracking servo circuit (not shown). ing. Then, the focused laser beam that passes through the objective lens 19 is emitted onto the surface of the recording film of the optical disc 11, and is emitted onto the recording track formed on the surface of the recording film of the optical disc 11. There is. In this state, the objective lens 19 is in a matching track state. In the focused point and focused track state, information can be written and read.

On the other hand, the diverging laser beam reflected from the recording film of the optical disk 11 is converted into a parallel beam by the objective lens 19 at the time of focusing, and is returned to the polarizing beam splitter 18 again. Then, it is reflected by this polarizing beam splitter 18 and guided onto a photodetector 21 by a condensing lens 20.
It is now photoelectrically converted. The output of the photodetector 21 is supplied to binarization circuits 26 and 27 via an amplifier 25, respectively.

The binarization circuit 26 is constituted by, for example, a comparator, and performs binarization by comparing the analog signal output from the amplifier 25 with a predetermined determination level 28. The determination level 28 is for detecting recorded pits, and is set as a signal at a lower level than the level of the reflected light signal from the recorded pits.

The binarization circuit 27 is constituted by, for example, a comparator, and performs binarization by comparing the analog signal output from the amplifier 25 with a predetermined determination level 29. The determination level 29 is set as a signal that is lower than the reflected light signal level when recording in an unrecorded area and higher than the reflected light signal level when recorded in a low recording area.

The output of the binarization circuit 26 is counted by a counter 30,
The count output is supplied to comparator 31. Comparator 3
1 compares the output of the counter 30 with a predetermined value 32 set in advance, and outputs a "0" signal when the output exceeds the predetermined value 32.

Further, the output of the binarization circuit 27 is supplied to the counter 33 together with the recording pulse S2. The counter 33 counts the AND signal of the output of the binarization circuit 27 and the recording pulse S2, and supplies the count output to the comparator 34. The comparator 34 compares the output of the counter 33 with a predetermined value 35 set in advance, and when the output exceeds the predetermined value 35, the output becomes "0".
“Output a signal.

The outputs of the comparators 31 and 34 are supplied to an AND circuit 36, and when the output of the AND circuit 36 becomes a "0" signal, this is output as the recording prohibition signal S3.

The reason why the recording inhibit signal S3 is output when it is detected that the predetermined value is 32.35 or more is because there is a part of the optical disc 11 where the reflective film is missing from the beginning, such as a pinhole. If there is, even if it is an unrecorded area, 2
This is because an overlapping recording detection signal is output, resulting in false detection. The predetermined value 32.35 is determined, for example, as follows. That is, the upper limit of the predetermined value is regulated by the burst error correction capability of the device.

This is because recording must be stopped while the data destroyed by double recording can be repaired by an error correction circuit (not shown). On the other hand, the lower limit of the predetermined value is determined by the allowable range of defects such as pinholes on the optical disk 11. That is, optical disk 1
While recording is being performed in the defective area above 1, the double recording detection signal continues to be output, but if the recording prohibition signal S3 is output before passing through the defective area, an erroneous detection will occur. The predetermined value must be at least the minimum allowable value.

The recording inhibit signal S3 from the AND circuit 36 is transmitted to the control circuit 1.
3 and is also supplied to an AND circuit 37.

The AND circuit 37 is connected to the control circuit 1 from an external device (not shown).
Recording pulse S according to recording data supplied via 3
2 as one input, and the recording prohibition signal S3 as the other input, and outputs a recording pulse S2 whose prohibition/permission is controlled. This recording pulse S2 is generated by the waveform shaping circuit 38.
is being supplied to. The waveform shaping circuit 38 is
It shapes the waveform of the recording pulse S2 and supplies it to a driver 42, which will be described later.

On the other hand, a photodetector 22 constituted by a photoelectric conversion element such as a photodiode, which is provided facing a light emitting port on the opposite side to the light emitting port for recording or reproducing laser light of the semiconductor laser oscillator 16, By being irradiated with the monitor light from 16, the monitor light is converted into an electrical signal (photocurrent) and supplied to the light output control circuit 24 as the light output monitor 15 of the semiconductor laser oscillator 16. .

The optical output control circuit 24 controls the optical output of the semiconductor laser oscillator 16 to keep it constant by inputting the optical output monitor signal output from the photodetector 22 and performing feedback control.

That is, the current-voltage conversion circuit 39 inputs the optical output monitor signal photoelectrically converted by the photodetector 22 and extracted as a current signal, and converts the light intensity received by the photodetector 22, that is, the optical output of the semiconductor laser oscillator 16. It converts it into a voltage signal according to the voltage and outputs it. The voltage signal output from this current-voltage conversion circuit 39 is supplied to an error amplifier 40. The error amplifier 40 uses the output voltage of the current-voltage conversion circuit 39 as one input, and uses the reference voltage 41 generated by a constant voltage source (not shown) as the other input, and compares these two types of voltages.
The difference is amplified and output as an error signal. Note that the reference voltage 41 is a constant voltage for obtaining the optical output necessary for reproduction, and is feedback-controlled to bring the output voltage of the current-voltage conversion circuit 39 closer to the reference voltage 41. of light output. The error signal from error amplifier 40 is supplied to driver 42 .

The driver 42 is supplied with a judgment pulse S4 from the waveform shaping circuit 38 according to the information to be recorded, so that the pre-recording output is output from the semiconductor laser oscillator 16. It has become. Note that the voltage signal output from the error amplifier 40 is input to the driver 42 during playback, and the voltage signal obtained by holding the voltage value input during the previous playback in a sample and hold circuit (not shown) during recording is input to the driver 42. These two inputs can be switched depending on whether recording or reproduction is to be performed. In both recording and reproduction, feedback control is performed based on the level of optical output during reproduction.

Next, the operation in the above configuration will be explained. A recording light beam output from an optical head 15 is emitted along a track of an optical disk 11 rotated by a motor 12, thereby forming recording pits corresponding to recording data. In this case, it is assumed that the optical disc 11 is composed of a recording film that reduces the amount of light reflected from the pits when recording pits are formed.

Now, the light reflected by the recording light beam from the optical disk 11 passes through the objective lens 19 and passes through the polarizing beam splitter 18.
It passes through the condensing lens 20 and enters the photodetector 21 where it is photoelectrically converted, and its output is amplified by the amplifier 25. The outputs of the amplifier 25 are as shown in FIG. 3(a) or (b), for example, and are supplied to binarization circuits 26 and 27, respectively. The binarization circuit 26 has a judgment level 28
(Refer to Figure 3) is manually performed, and this judgment level is 2.
The outputs (recorded stream pits) a and b of eight or more amplifiers 25 are detected.

The output of the binarization circuit 26 is counted by a counter 30, and the count value is compared with a predetermined value 32 by a comparator 31. Then, when the count value is equal to or greater than the predetermined value 32, the comparator 31 outputs a "0" level signal.

On the other hand, the binarization circuit 27 has a judgment level 29 (FIG. 3a).
) is input, and when the output of the amplifier 25 is equal to or lower than this determination level 29, a "1" signal is output. The output of the binarization circuit 27 is supplied to the counter 33 together with the recording pulse S2 from the AND circuit 37, so that
Both AND signals are counted. This allows the third
Detection and counting of numbers 4 and 5 in FIG. 4(a) are performed.

The count value of the counter 33 is set to a predetermined value 3 by the comparator 34.
A comparison with 5 is made. Then, the count value is the predetermined value 3
When the value is 5 or more, the comparator 34 outputs a "0" level signal.

In this way, when the comparator 31 or the comparator 34 outputs a "0° level signal," the output of the AND circuit 36 also becomes "0".
" signal, and this is output as the recording prohibition signal S3. Then, this recording prohibition signal S3 is supplied to the AND circuit 37, and the gate of the AND circuit 37 is closed, and the recording pulse S2 is cut off. Recording is stopped.Therefore, the recording prohibition signal S3 is used as a control signal to stop recording.

The recording inhibit signal S3 is also supplied to a control circuit 13 composed of a microprocessor or the like, and is used by the control circuit 13 to determine the next operation. For example, a recording prohibition signal S3 is used to notify that double recording has occurred, and processing such as starting the recording again from the beginning is performed.

Here, double recording due to track off will be explained with reference to FIGS. 2 and 3. Figure 2 shows optical disc 1
This figure shows that recording is being performed on the third track of 1 with recording pulses of 1.2, 3, and 4.5 as shown in FIG. 3(C). Recording is performed up to 1.2.3 on the third track in Figure 2, and if a track skip occurs for some reason at this point and the track jumps to the second track, recording will be done as 4.5, which is indicated by diagonal lines. This shows double recording on the already recorded bits. Further, when jumping to the first track at time 3 of the third track, recording of 4'5' is performed and the recorded bit a.

It shows that recording is being performed in the middle of part b.

In this way, if track skipping occurs during recording, the two situations described above may occur.

When the reflected light from the optical disk 11 at this time is converted into an electrical signal, the signal shown in FIG. 3(a) is obtained when a track skip occurs on the second track, and the signal shown in FIG. b). Therefore, as mentioned above, in the case of FIG. 3(a), during the period of recording pulse 4.5, the judgment level is 29 or less, and there is no reflected output (4, 5).
can be detected. Furthermore, as described above, in the case of FIG. 3(b), it is possible to detect recorded pitches a and b exceeding the determination level 28.

[Effects of the Invention] As detailed above, according to the present invention, the magnitude of the reflected light of the recording light beam from the optical recording medium is detected, and recorded bits are detected between the recording light beams. By simultaneously detecting whether or not a file exists, it is possible to reliably detect double recording in the unlikely event that it occurs during recording, prevent the recorded information from being destroyed, and provide extremely reliable information. Recording devices can be provided.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, in which Fig. 1 is a schematic diagram of the configuration of an optical disc device, Fig. 2 is a diagram illustrating a double recording state due to the optical disc going off track, and Fig. FIG. 3 is a diagram illustrating signals and operations caused by reflected light from the optical disc in FIG. 2; 11... Optical disk (optical recording medium), 13... Control circuit (control means), 15... Optical head, 16...
Semiconductor laser oscillator (light output means), 19... Objective lens, 21.22... Photodetector, 24... Light output control circuit, 26.27... Binarization circuit, 30.33.・
・Counter (counting means), 31.34... Comparator, 3
6゜37...AND circuit.

Claims (1)

[Scope of Claim] An information recording apparatus that records information in the form of pits on an optical recording medium by emitting a pulsed recording light beam from a light output means to the optical recording medium, comprising: a first detection means for detecting that the reflected light of the optical recording medium from the optical recording medium is below a predetermined level; a second detection means for detecting; a counting means for respectively counting the detection result of the first detection means and the detection result of the second detection means during the recording operation; and one of the respective count values of the counting means. An information recording apparatus comprising stop control means for stopping emission of the recording light beam from the light output means when the count value reaches a predetermined value.