JPH03116440A - 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 32 and 30 which count the detection results of the detecting means during recording, a cumulating means 31 for cumulating their counted value, and a stop control means 33 which stops the emission of the recording light beam by a light output means 16 when the cumulated value reaches a specific value. Consequently, accidental double recording is surely detected during recording to prevent the information which is already recorded from being destroyed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an information recording device that records 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, even if it is not intended for recording, undefined information will be written on the optical disc, destroying 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, and 4.5, as shown in FIG. Unable to detect double recording (4, 5). In addition, with the method of detecting only the reflected light of the recording pulse, when recording is performed as shown in 1.2.3.4' and 5' in Figure 2, the double recording state of the first track cannot be detected. .

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 respectively counting the detection results, a totalizing means for calculating the cumulative total of each count value of the counting means, and stopping emission of the recording light beam of the light outputting means when the cumulative value of the cumulative totaling means reaches a predetermined value. and stop control means for stopping the vehicle.

(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 an optical head 15. It is composed of detectors 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 pre-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 movably in the forward axis direction by a lens actuator 23 as a lens driving means. 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, the objective lens 19 is in a focused state.

The objective lens 19 is also movable in a direction perpendicular to the optical axis, and is moved in a direction perpendicular to the optical axis by a servo signal from a tracking servo circuit (not shown). There is. 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 a recorded bit, and is set as a signal at a lower level than the level of the reflected light signal from the recorded bit.

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 an adder 31. Further, the output of the binarization circuit 27 is supplied to the counter 32 together with the recording pulse S2. The counter 32 is connected to the binarization circuit 27
Count the AND signal of the output of and the recording pulse S2,
The count output is supplied to an adder 31. Adder 31
adds the outputs of both counters 30 and 32 and supplies the addition result to a comparator 33. The comparator 33 is the adder 31
The output is compared with a predetermined value 34 set in advance, and when the output exceeds the predetermined value 34, a recording prohibition signal S3 is output.

The reason why the recording prohibition signal S3 is output when it is detected that the predetermined value is 34 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. This is because a double recording detection signal is output even in an unrecorded area, resulting in false detection. The predetermined value 34 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, while recording is being performed on a defective area on the optical disk 11, 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. Therefore, the predetermined value must be greater than the minimum allowable value.

The recording inhibit signal S3 from the comparator 33 is supplied to the control circuit 13 and also to the AND circuit 35. The AND circuit 35 uses a recording pulse S2 according to recording data supplied from an external device (not shown) via the control circuit 13 as one manual input, and inputs a recording prohibition signal S3 on the other input to prohibit/permit recording. It outputs pulse S2.

This recording pulse S2 is supplied to a waveform shaping circuit 36. The waveform shaping circuit 36 outputs a recording pulse S
2 is waveform-shaped and supplied to a driver 40, 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, is a semiconductor laser oscillator. When the monitor light from the semiconductor laser oscillator 16 is irradiated, the monitor light is converted into an electric signal (photocurrent) and supplied to the light output control circuit 24 as a light output monitor signal 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 37 manually converts the optical output monitor signal photoelectrically converted by the photodetector 22 and extracted as a current signal, and converts it into 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 37 is supplied to an error amplifier 38. The error amplifier 38 uses the output voltage of the current-voltage conversion circuit 37 as one input, and uses the reference voltage 39 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 39 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 37 closer to the reference voltage 39, so that the output voltage from the semiconductor laser oscillator 16 is constant. of light output. The error signal from error amplifier 38 is adapted to be supplied to driver 40 .

The driver 40 is supplied with a recording pulse S4 corresponding to the information to be recorded from the waveform shaping circuit 36, so that the optical output for recording is output from the semiconductor laser oscillator 16. ing. Note that the driver 40 receives the voltage signal output from the a-difference amplifier 38 during playback, and receives the voltage signal obtained by holding the voltage value input during the previous playback in a sample-and-hold circuit (not shown) during recording. These two manual functions 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 output of the amplifier 25 is, for example, as shown in FIG. 3(a) or (b), and is supplied to binarization circuits 26 and 27, respectively. The binarization circuit 26 has a judgment level 28
(See Figure 3) is input, and this judgment level 2
The outputs (recorded droplet pip) a and b of eight or more amplifiers 25 are detected.

The output of the binarization circuit 26 is counted by a counter 30, the count value is sent to an adder 31 for addition, and a comparator 33 compares the addition result with a predetermined value 34. When the addition result is equal to or greater than the predetermined value 34, the comparator 33 outputs a "0" level signal, that is, a recording prohibition signal S3.

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 below this judgment level 29, it outputs a “1° signal. By being supplied to
Both AND signals are counted. This allows the third
Detection and counting in 4.5 in Figure (a) are performed.

The count value of the counter 32 is sent to the adder 31 for addition in the same manner as described above, and the comparator 33 compares the addition result with a predetermined value 34. When the addition result is equal to or greater than the predetermined value 34, the comparator 33 outputs a "0° level signal, that is, a recording prohibition signal S3."

When the recording inhibit signal S3 is output from the comparator 33, this signal S3 is supplied to the AND circuit 35, which closes the gate of the AND circuit 35 and cuts off the recording pulse S2, thereby stopping recording. It will be done. 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 the first disk 1.
This figure shows that recording is being performed on the third track of No. 1 using recording pulses 1.2.3.4.5 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 performed as 4, 5, as indicated by diagonal lines. This shows that double recording is being performed on top of an already recorded pit. Further, when jumping to the first track at time 3 of the third track, recording of 4' and 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.

If the reflected light from the first disk 11 at this time is converted into an electrical signal, the result will be as shown in Fig. 3(a) when a track jump occurs on the second track, and as shown in Fig. 3 (a) when a track jump occurs on the first track. (b). Therefore, as described above, in the case of FIG. 3(a), there is no reflected output (4, 5) at the judgment level 29 or lower during the period of recording pulses 4 and 5.
can be detected. Furthermore, as described above, in the case of FIG. 3(b), recorded pits a and b exceeding the determination level 28 can be detected.

[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 the presence or absence of data, it is possible to reliably detect double recording in the unlikely event of recording, and prevent the recorded information from being destroyed in the unlikely event that it occurs, resulting in extremely high reliability. Information recording devices can be provided.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic diagram of the configuration of the first disk device, Fig. 2 is a diagram illustrating a double recording state due to the optical disk going off track, and Fig. 3 is a 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, 30.32.・
- Counter (counting means), 31... Adder (cumulative means), 33... Comparator, 35... 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 detecting means for detecting; a counting means for respectively counting the detection results of the first detecting means and the second detecting means during recording operation; and a totalizing means for calculating the cumulative total of each count of the counting means. and stop control means for stopping emission of the recording light beam from the light output means when the cumulative value of the cumulative total reaches a predetermined value.