JPH03116424A - 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 the reflected light of a recording light beam which is reflected by an optical recording medium, and detecting whether or not there is a recorded pit between recording light beams 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 reflected by the optical recording medium 11 being lower than a specific level and a 2nd detecting means 26 which detects pits recorded yet with the reflected light of the recording light beam from the optical recording medium 11. A stop control means 33 which stops the emission of the recording light beam by a light output means 16 during recording according to the detection result of the 1st or 2nd detecting means is provided to decrease the light reflection factor of an optical recording medium 11 at its information recording part. 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 OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to an information recording apparatus 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). 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 detecting means for detecting recorded pits that have already been recorded by the reflected light of the recording light beam from the optical recording medium; stop control means for stopping emission of the recording light beam from the light output means based on the detection result of either one of the second detection means;
By recording information on the optical recording medium,
It is characterized by a decrease in the light reflectance of that part (function).It detects the magnitude of the reflected light of the recording light beam from the optical recording medium, and also detects the recorded pit between the recording light beams. By simultaneously detecting whether or not a double recording state exists, it is possible to reliably detect all double recording states. (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 disc 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 j7 and enters the objective lens 19, and is focused by the objective lens 19 toward the recording film of the optical disk 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 optical disk 11 marked By, 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 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 an already recorded area. The output of the binarization circuit 26 is counted by a counter 30,
The currant output is supplied to adder 31. Also,
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 2
7 and the recording pulse S2 are counted, and the count output is supplied to the adder 31. Adder 3
1 adds the outputs of both counters 30 and 32 and supplies the addition result to a comparator 33. The comparator 33 is the adder 3
Compare the output of 1 with a predetermined value 34 set in advance,
When the value exceeds a predetermined value of 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 the 2ii 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, when recording is being performed on a defective portion of the optical disc 11, the above-mentioned 2@recording detection signal continues to be output, but the recording prohibition signal S3 is output before passing through the defective portion.
If this is output, it will result in false detection, so the predetermined value must be at least 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 receives a recording pulse S2 corresponding to recording data supplied from an external device (not shown) via the control circuit 13 as one input, and receives a recording prohibition signal S3 as 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, 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 inputs the optical output monitor signal photoelectrically converted and extracted as a current signal by the photodetector 22, 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 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 during reproduction, the voltage signal output from the error amplifier 38 is input to the driver 40, and during recording, a voltage signal in which the voltage value input during the previous reproduction is held by a sample and hold circuit (not shown) is input. 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 destination beam output from the optical head 15 is emitted along the track of the optical disk 11 rotated by the 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
(See Figure 3) is input, and this judgment level 2
Outputs a and b of eight or more amplifiers 25 (recorded Gulf stream pits) 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 equal to or lower than this determination level 29, a "1" signal is output. The output of this binarization circuit 27 is supplied to the counter 32 together with the recording pulse S2 from the AND circuit 35, so that
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, the recording is correct signal S3 notifies that double recording has occurred, and processing such as starting the recording again from the beginning is performed. Here, double recording due to off-track 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 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 performed as 4, 5, as indicated by diagonal lines. This shows that double recording is being performed on top of an already recorded pit. Furthermore, when jumping to the first track at point 3 of the third track, recording of 4'5' is performed and the recorded pit 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 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 pits 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 drawings 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 off-track of an optical disc, and Fig. 3 is a diagram showing the structure of an optical disc device. FIG. 2 is a diagram illustrating signals and operations caused by reflected light from an optical disc. 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, 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; and a stop control means for stopping the emission of the recording light beam from the light output means based on the detection result of either the first or second detection means during a recording operation. When information is recorded on the optical recording medium,
An information recording device characterized in that the light reflectance of that portion is reduced.