JPH0765379A - Information recording device - Google Patents

Abstract

PURPOSE:To improve the reliability of verification by exactly detecting the edge of a recording signal without being affected by an old information component and a noise. CONSTITUTION:This device is provided with a means for simultaneously recording information and reproducing information recorded at present, a differentiation circuit 15 for differentiating the reproduced signal, an adding circuit 17 for adding the differential signal to the signal delayed by a prescribed time, and a positive and a negative comparators 18, 19 for binarizing the added signal by means of a positive and a negative reference voltages V+ and V- and detecting the edges of the rise and the fall of the recording signal and recording and verification are performed at the same time based on the outputs of the comparators. Two positive and two negative comparators for each are provided, they are controlled so that two positive and two negative comparators for each are operated with a prescribed time interval, the outputs of the positive and negative comparators are ANDed, the edge of the recording signal is detected and recording and verification are simultaneously performed based on the detected edge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus for recording information on an information recording medium such as a magneto-optical disk, and more particularly to an information recording apparatus for reproducing recorded information at the same time as recording operation to confirm recording. is there.

[0002]

2. Description of the Related Art In recent years, an information recording apparatus for optically recording information is required to have a high recording speed, and one method for meeting the demand is to perform verification at the same time as recording information. So-called direct verify is being attempted. As a method of such direct verification, for example, the applicant of the present application has proposed a magneto-optical recording method in which the information signal being recorded is reproduced from the reflected light of the recording light beam to confirm whether or not there is a difference from the signal to be recorded. −
Filed as 175159. Further, according to this magneto-optical recording method, the time required for recording confirmation becomes unnecessary, and there is an effect that the recording speed of information can be remarkably increased. However, in the above-mentioned magneto-optical recording method, when the new information is overwritten on the old information, the old information component is mixed in the obtained reproduction signal for recording confirmation, and the reliability of the recording confirmation signal deteriorates. I was afraid.

In order to solve these problems, the inventors of the present invention have proposed an information recording apparatus for extracting a frequency component of a newly recorded recording signal from a reproduced signal for recording confirmation in Japanese Patent Application No. 3-354085. Filed as an issue. The information recording device will be described below with reference to FIG. In FIG. 7, 1 is a semiconductor laser provided as a light source for recording and reproduction, 2 is a collimator lens for collimating the divergent light flux of the semiconductor laser 1, and 3 is the incident light flux from the semiconductor laser 1 and the recording medium 5. It is a half prism for separating the reflected light flux from. Reference numeral 4 is an objective lens for focusing the light flux of the semiconductor laser 1 into a minute light spot and irradiating it onto the recording medium 5. As the recording medium 5, a disc-shaped magneto-optical recording medium which is rotated by the drive of a spindle motor (not shown) is used, and its recording layer is composed of two magnetic layers of a first magnetic layer and a second magnetic layer exchange-coupled to each other. It consists of The first magnetic layer has characteristics of low coercive force and high Curie temperature at room temperature, and the second magnetic layer has characteristics of higher coercive force and lower Curie temperature than the first magnetic layer. Reference numeral 6 is a magnetic head which is arranged to face the objective lens 4 with the recording medium 5 interposed therebetween. The magnetic head 6 generates a magnetic field modulated according to a recording signal and applies it to the recording medium 5.

Reference numeral 9 is a polarization beam splitter for splitting the reflected light from the recording medium 5 into two, 10 is an optical sensor for detecting each of the split light beams, and 11 is a detection signal from the optical sensor 10. It is a differential amplifier that detects motion and reproduces recorded information as a magneto-optical signal. This information reproduction is performed simultaneously with the information recording by the reflected light from the recording medium 5. Reference numeral 29 is a reproduction filter used during normal information reproduction, and reference numeral 30 is a verification filter used for extracting a verification signal during information recording. The two filters 29 and 30 are switched by a changeover switch 31 according to the operation mode of the device. Verify filter 3
The band of 0 is set so that a signal component in a frequency band higher than that of the reproduction filter 29 can be extracted. That is, at the time of information recording, the band of the filter is set so as to generate only the verifying signal by extracting only the high frequency components of the rising and falling edges of the reproduced signal.

Reference numeral 32 is a binarizing circuit for binarizing a signal input through any of the filters, and 14 is a CPU for controlling the entire apparatus, which controls the changeover switch 31 and the information signal and the binarizing circuit. The signals obtained in 32 are compared and verification or the like is performed. Reference numeral 7 is a drive circuit for driving the magnetic head 6 according to the recording information, and by controlling the current of the magnetic field generating coil provided in the magnetic head 6, the polarity of the magnetic field corresponding to the recording signal. To modulate.

Next, the operation of the information recording apparatus will be described with reference to the time chart shown in FIG. When recording information, first, the semiconductor laser 1 irradiates a recording light flux having a constant intensity set to the recording power. This recording light beam enters the objective lens 4 via the collimator lens 2 and the half prism 3, where it is focused into a minute light spot and is irradiated onto the information track of the recording medium 5. In this case, the recording medium 5 starts to rotate at a constant speed by driving a spindle motor (not shown), and the light spot is subjected to focus control and tracking control by control operations of a focus control circuit and a tracking control circuit (not shown). . As a result, the light spot is focused on the medium surface and starts scanning while following the information track. Note that the changeover switch 31 is connected to the b side when recording information. In this way, the magnetic field modulated according to the recording signal is applied from the magnetic head 6 to the temperature rising portion of the recording medium 5 while the recording medium 5 is irradiated with the recording light flux.

FIG. 8B shows this recording signal, and FIG. 8A shows the signal component of the old information originally recorded on the information track. As a result, the magnetization of the first magnetic layer is oriented in the direction of the external magnetic field, and information is recorded. The magnetization direction of the first magnetic layer is detected by the optical sensor 10 in real time as a change in the magneto-optical effect (Kerr effect or Faraday effect) of the reflected light of the recording light flux with which the recording medium 5 is irradiated. Specifically, the recording light flux irradiated to the magnetic field application position of the magnetic head 6 is reflected from the recording medium 5 and is incident on the optical sensor 10 via the objective lens 4, the half prism 3, and the deflection beam splitter 7. . Then, the output of the optical sensor 10 is input to the differential amplifier 11 and differentially amplified, whereby the reproduction signal of the information currently recorded is taken out. FIG. 8C shows this reproduced signal, which is overwritten from the old data on the recording medium 5, and therefore is a signal in which old data and new recorded data are mixed as shown in the figure.

The obtained reproduction signal is input to the verifying filter 30, and only the signal in the frequency band set by the filter 30 is extracted. Here, the differential amplifier 11
In addition to the newly recorded signal component, the reproduced signal obtained in step 1 contains the component of the old data that was originally recorded on the recording medium 5 and should be erased by overwriting. The two signals have different frequency components, and the new recording component changes instantaneously according to the reversal of the magnetic field.
It contains high frequency components due to magnetic field modulation. On the other hand, the old data component has a high frequency component limited by the shape of the light spot and the recording bit or the relative speed.

Therefore, the verifying filter 30 cuts off the old data component in the reproduced signal and extracts the high frequency component which is the edge component of the newly recorded signal. Figure 8 (d)
Indicates a signal extracted by the verifying filter 30. The output signal of the verifying filter 30 is sent to the binarizing circuit 32 and binarized into a pulse signal. Then, the binarized signal is sent to the CPU 14 and compared with the current record information to determine the verification. In this case, if the record information and the verify information do not match, it is determined as an error, and re-recording is performed on the same information track of the recording medium 5 or another alternative track. Of course, when there is no verify error, the following information is recorded without re-recording.

On the other hand, during normal information reproduction, the change-over switch 31 is switched to the a side, and the reproduction filter 29 is selected. In this state, the rotating recording medium 5 is irradiated with the reproducing light flux of the reproducing power from the semiconductor laser 1, and the information on the information track is sequentially output from the differential amplifier 11. The high frequency noise is removed from the obtained reproduction signal by the reproduction filter 29, and thereafter the edge portion is pulsed by the binarization circuit 32 to be converted into a signal suitable for reproduction. This binarized signal is sent to the CPU 14, where reproduction data is generated by performing predetermined signal processing. Then, according to the above information recording apparatus, by extracting only the recording signal from the reproduction signal reproduced simultaneously with the recording,
There is an effect that the influence of the old data component on the medium included in the reproduction signal can be removed, and thus verification at the same time as recording can be performed with high reliability.

[0011]

By the way, FIG. 8 is a waveform diagram showing signals of respective parts at the time of information recording of the above information recording / reproducing apparatus. FIG. 8 shows a ratio of recording frequencies of old information and new information. It is a signal waveform diagram when it overwrites as 4 to 5. Further, FIG. 9 is a signal waveform diagram when the ratio of the recording frequencies of the old information and the new information is overwritten 5: 4 under different conditions. 8A and 9A are the old information signal components recorded on the recording medium, and FIGS. 8B and 9A.
(B) is a recording signal of new information overwritten thereon. The old information signal component does not include a sharp high frequency component as shown in the figure. Further, FIGS. 8C and 9C are reproduction signals differentially detected by the differential amplifier 11 and have a signal waveform as if the old information component and the new information component were added at a predetermined ratio. Further, FIGS. 8D and 9D are signals obtained by the verifying filter 30, and the component S mainly corresponding to the edge of the recording signal is extracted.

However, in addition to this, since the new information is overwritten on the old information, the components P, Q, and R due to the influence of the crosstalk of the old information component are slightly included. The verification reproduction signal thus obtained is binarized by the binarization circuit 32.
9D, the S portion shown in FIG. 9D becomes an edge of the binarized pulse, and this becomes a signal corresponding to the edge of the recording signal. Then, by comparing the edges of the binarized signal and the recording signal, it is possible to confirm the recording in real time. Here, the optical sensor 10 and the differential amplifier 11
When the high frequency band of is sufficiently high, the height of the signal component S can be made sufficiently higher than the other signal components P, Q, and R by increasing the cutoff frequency of the verifying filter 30.
You can confirm the record correctly.

However, if the frequency bands of the optical sensor 10 and the differential amplifier 11 are limited, the verifying filter 30 will be used.
The cutoff frequency must be lowered. Therefore, as shown in FIGS. 8 and 9, the difference between the component S corresponding to the edge of the recording signal and the other components P, Q, and R becomes unclear,
If binarization is performed in this state, P, Q, and R components other than the S component may also be binarized. Therefore, there is a possibility that the recording may be judged to be abnormal even if the recording is correctly performed, and an incorrect verification may be performed. In addition, widening the signal band and increasing the cutoff frequency of the verifying filter 30 may deteriorate the signal-to-noise ratio and cause erroneous verification due to noise.

The present invention is a further improvement of the above-mentioned prior application, in which the edge of the recording signal can be accurately detected without being affected by the old information component and noise, thereby further improving the reliability of verification. The purpose is to provide a device.

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to record information in an information recording apparatus for irradiating an information recording medium with a light beam to record information, and at the same time recording information from reflected light of a recording light beam. Means for reproducing the information, a differentiation circuit for differentiating this reproduction signal, an addition circuit for adding the differentiation signal of this differentiation circuit and a signal obtained by delaying this for a predetermined time, and the addition of this addition circuit Positive and negative comparators are provided for binarizing the signals with predetermined positive and negative reference voltages to generate signals corresponding to the rising edge and the falling edge of the recording signal, and based on the output signals of the positive and negative comparators. This is achieved by an information recording apparatus characterized by performing verification at the same time as recording by determining whether or not the recording signal is correctly recorded.

Further, an object of the present invention is to record information at the same time as recording of information in an information recording apparatus for recording information by irradiating an information recording medium with a light beam. A means for reproducing, a differentiating circuit for differentiating the reproduced signal, and 2 for binarizing the differential signal of the differentiating circuit with a predetermined positive reference voltage to generate a signal corresponding to the rising edge of the recording signal. Two positive comparators, two negative comparators for binarizing the differential signal with a predetermined negative reference voltage to generate a signal corresponding to the falling edge of the recording signal, the two positive comparators and two negative comparators. A control circuit for controlling each of the comparators to operate at a predetermined time interval, and a logical product of output signals of the two positive comparators and two negative comparators. An AND circuit for taking provided, by determining whether the recording signal based on the output signal of the AND circuit is correctly recorded,
This is achieved by an information recording device characterized by performing verification at the same time as recording.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the information recording apparatus of the present invention. In FIG. 1, the same parts as those of the device of FIG. 7 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 1, reference numeral 12 is a reproducing circuit for reproducing recorded information based on the magneto-optical signal output from the differential amplifier 11 during normal information reproduction. Reference numeral 13 is a verify signal reproducing circuit for reproducing the currently recorded information in real time based on the magneto-optical signal of the differential amplifier 11 when recording the information. The verify signal reproducing circuit 13 actually detects the rising and falling edges of the recorded information and outputs them as edge detection pulses. The specific configuration thereof will be described later in detail.
The output signal of the verify signal reproducing circuit 13 is sent to the CPU 14, where the edge detection pulse is compared with the edge of the recording signal to determine whether the verification is successful or not. Other configurations are the same as those in FIG. 7.

FIG. 2 is a circuit diagram showing a specific example of the verify signal reproducing circuit 13. Reference numeral 15 in the figure is a differential amplifier 1.
A differentiating circuit for differentiating the magneto-optical signal 1 and a delay 16 for delaying the output signal of the differentiating circuit 15 for a predetermined time. The output signal of the differentiating circuit 15 and the signal delayed by the delay 16 are added by the adding circuit 17 to generate a signal for emphasizing the portion corresponding to the edge of the recording signal as described later. 18 is an adder circuit 17
Positive comparator for binarizing a predetermined positive reference voltage V ₊ output signal of 19 predetermined negative reference voltage V _- is a negative comparator for binarizing with. The positive comparator 18 detects the rising edge of the recording signal, and the negative comparator 19 detects the falling edge, and these signals are detected by the OR circuit 20.
By taking the logical sum with, the edge detection pulse corresponding to each edge of the recording signal is output.

Next, the specific operation of this embodiment will be described in detail with reference to the time chart shown in FIG. Figure 3
(A) is a recording signal generated by encoding recording data by the CPU 14, and is output to the magnetic field applying circuit 7 as a magnetic field modulation signal. The magnetic field application circuit 7 drives the magnetic head 6 based on the recording signal, and the magnetic head 6 generates a magnetic field modulated according to the recording signal and applies it to the recording medium 5. On the other hand, the recording light beam of the semiconductor laser 1 scans the information track of the recording medium 5 in a rotating state, and a series of information is recorded on the information track by irradiation of this light beam and application of a modulation magnetic field. At the same time, the recording light beam is reflected by the recording surface of the recording medium 5, and the reflected light is detected by the two optical sensors 10. The detection signal of the optical sensor 10 is differentially detected by the differential amplifier 11 and reproduced as a magneto-optical signal. FIG. 3B shows the magneto-optical signal thus obtained.

When there is no old information or noise on the recording medium 5, the magneto-optical signal has almost the same signal waveform as the recording signal as shown by the broken line in FIG. 3B.
Actually, as shown by the solid line in FIG. 3B, the signal waveform has a recording signal component in which old information components and noise are mixed. The magneto-optical signal is differentiated by the differentiating circuit 15, and the differentiated signal is output as shown in FIG. The signal shown by the solid line in FIG. 3C is the differential signal of the differentiating circuit 15, and the signal shown by the broken line is the signal obtained by delaying the differential signal by the delay 16 by the predetermined time Δt. The portion indicated by Q and R in the differential signal of FIG. 3C is a portion which is distorted by the influence of the old information component and noise.

The output signals of the differentiating circuit 15 and the delay 16 are added by the adding circuit 17, and the added signal is output as shown in FIG. 3 (d). Here, when the differential signal and the signal obtained by delaying the differential signal by a predetermined time Δt are added, since the signal components of the recorded information and the old information have a certain degree of correlation at the point delayed by Δt, as shown in FIG. 3D. The parts corresponding to the edges are emphasized. On the other hand, noise as indicated by R does not correlate at the point where the recorded information and the old information component are delayed by Δt, so that they are not mutually emphasized and a signal with improved signal-to-noise ratio S / N is obtained. Can be obtained.

The output signal of the adder 17 is a reference voltage of a predetermined positive comparator 18 and negative comparator 19, respectively positive and negative V _+, V _- in binarized, recorded as shown in FIG. 3 (e), (f) A pulse corresponding to the rising edge of the signal and a pulse corresponding to the falling edge are output. These pulse signals are further ORed by the OR circuit 20 and output as edge detection pulses corresponding to the rising and falling edges of the recording signal as shown in FIG. 3 (g). The obtained edge detection pulse is sent to the CPU 14, and verification is performed in real time by determining whether the edge position of the recording signal and the edge detection pulse match. During normal information reproduction, the magneto-optical signal is sent to the reproduction circuit 12, and reproduction data is generated by performing predetermined signal processing such as binarization.

In this embodiment, the reproduced signal obtained at the same time as recording is differentiated by a differentiating circuit having a high cutoff frequency to suppress the old information component, and this differential signal and a signal obtained by delaying this for a predetermined time are added. By doing so, it is possible to obtain a signal with improved S / N while suppressing the influence of noise. That is, since portions corresponding to edges are emphasized and noise is not emphasized, a signal with improved S / N can be generated. Therefore, since the rising edge and the falling edge of the recording signal are detected based on the addition signal that suppresses the old information component and noise, only the edge of the recording signal is accurately affected by the old information component and noise. Can be detected. Therefore, it is possible to further improve the reliability of the verification without causing erroneous verification even though the recording is correctly performed.

FIG. 4 is a circuit diagram showing another embodiment of the verify signal reproducing circuit 13. This embodiment is an example of detecting an edge of a recording signal by digital signal processing. In FIG. 4, the magneto-optical signal is the A / D converter 21.
It is digitized by and is temporarily held by the latch 22. The signal of the latch 22 is further output to the latch 23 and the adder 24, and the temporary signal is held in the latch 23.
The signal of No. 3 is output to the adder 24 with a time delay of Δt with respect to the signal of the latch 22. In the adder 24, the signals of the latches 22 and 23 are added, and the added signal is differentiated by the digital filter 25 by digital signal processing. Then, the differentiated signal is sent to the comparators 26 and 27, the rising edge and the falling edge of the recording signal are detected, and the OR circuit 28 takes the logical sum to output the edge detection pulse of the recording signal. . As described above, in the present embodiment, the edge of the recording signal is detected by the digital signal processing, but in the present embodiment, the recording signal can be accurately measured without being affected by the old information component and noise, just like the above-mentioned embodiments. It is possible to detect only the edge of, and to perform the verification accurately.

FIG. 5 is a circuit diagram showing another embodiment of the verify signal reproducing circuit 13. In FIG. 5, 15
Is a differentiating circuit for differentiating the magneto-optical signal output from the differential amplifier 11, and 40 and 41 are differentiating circuits 15 respectively.
Is a positive comparator for binarizing the differential signal of V.sub.2 with a predetermined positive reference voltage V.sup. ₊ . Positive comparator 40 is a CPU
The control signal E1 of 14 controls the operation of the positive comparator 41 by the control signal E2.
Reference numeral 41 is configured to binarize the differential signal when the control signals E1 and E2 are input. Also, 42
And 43 respectively differentiate the differential signal to a predetermined negative reference voltage V _−.
It is a negative comparator for binarizing. Similarly, the operation of the negative comparators 42 and 43 is controlled by the control signals E1 and E2 output from the CPU 14. 44 is an AND circuit for taking the logical product of the output signals of the positive comparators 40 and 41, 45 is an AND circuit for taking the logical product of the negative comparators 42 and 43, and 46 is the logical sum of the AND circuits 44 and 45 It is an OR circuit for. This OR circuit 46
The output signal of the CPU is used as the edge detection pulse of the recording signal.
It is output to 14.

Next, the specific operation of the above embodiment will be described with reference to FIG. FIG. 6A shows a recording signal, and FIG. 6B.
Is a magneto-optical signal output from the differential amplifier 11 simultaneously with the recording of this recording signal. As described above, the magneto-optical signal has the same waveform as the recording signal as shown by the broken line in FIG. 6B if there is no old information component or noise. The waveform becomes distorted by the effect of. This magneto-optical signal is differentiated by the differentiating circuit 15 as shown in FIG. 6C, and then output to the positive comparators 40 and 41 and the negative comparators 42 and 43.

Here, the control signals E1 and E2 are signals for controlling each of the positive and negative comparators to operate in the vicinity where the edge of the recording signal should originally exist. In addition, the control signal E1
And E2 are output from the CPU 14 at a predetermined time interval Δt as shown in FIGS. 6 (d) and 6 (e). The positive comparators 40 and 41 and the negative comparators 42 and 43 are permitted to operate when the control signal E1 or E2 is at high level, and are prohibited from operating when they are at low level. In the positive comparator 40, the differential signal and the reference voltage V ₊ (FIG. 6C) are compared while the control signal E1 is at the high level, and as a result, the differential signal level is V ₊ as shown in FIG. 6F. When it is higher than the above, a high level pulse signal is output. Similarly in the positive comparator 41, the differential signal and the reference voltage V ₊ are compared while the control signal E2 is at the high level, and when the level of the differential signal is higher than the reference voltage as shown in FIG. Is output. The negative comparator similarly control signal also in the 42, 43 E1, E2 differential signal to a period of high level respectively and the reference voltage V _- (to FIG. 6 (c)) are compared, the result 6
As shown in (h) and (i), a high level pulse signal is output when the level of the differential signal exceeds V ₋ .

The output signals of the positive comparators 40 and 41 are ANDed by the AND circuit 44, and the output signals of the negative comparators 42 and 43 are ANDed by the AND circuit 45. ) And (k) are output. The output signal of the AND circuit 44 is the rising edge of the recording signal, and the AND circuit 45
The output signal of is a signal indicating a falling edge. The output signals of the AND circuits 44 and 45 are further ORed by the OR circuit 46, and as a result, edge detection pulses corresponding to the rising edge and the falling edge of the recording signal are output as shown in FIG. . This edge detection pulse is C
The verification is performed simultaneously with the recording by sending to the PU 14 and determining whether the edge of the recording signal and the edge of the edge detection pulse match as in the above-described embodiment.

In this embodiment, when the magneto-optical signal is differentiated by a differentiating circuit having a high cutoff frequency to suppress the old information component, and when the differential signal and the reference voltage are compared to detect the edge of the recording signal, The detection is performed twice with a predetermined time interval Δt, and the logical product of the two detections is performed to detect the edge of the recording signal. Therefore, even if the magneto-optical signal contains old information components and noise, Only edges can be detected accurately. More specifically, for example, the differential signal shown in FIG.
Noise is included as indicated by R in (c), and when the edge is detected by the positive comparator 40 as it is, a thin pulse N appears as noise at a position where there is no edge as shown in FIG. 6F. Therefore, in the present embodiment, the positive comparator 41 detects the edge again with a delay of time Δt, and the detected result of the positive comparator 40 is ANDed to detect the edge.
As described above, a pulse due to noise does not appear in the output of the AND circuit 44, and only the edge of the recording signal can be accurately detected. That is, even if noise is superimposed on the differential signal and an edge is erroneously detected by the positive and negative comparators,
Since the noise having a width narrower than the time Δt is removed as noise, only the edge of the recording signal can be accurately detected.

In the above embodiments, the magneto-optical disk recording apparatus has been described as an example of the information recording apparatus, but the present invention is not limited to the magneto-optical disk recording apparatus as long as it can reproduce recorded signals at the same time. However, it can be applied. In the embodiment, the edge of the recording signal is detected, and the edge of the recording signal is compared to perform the verification. However, other than this, for example, reproduction data is generated from the edge detection pulse, and this is compared with the recording data. It is also possible to perform verification by comparing.

[0031]

As described above, according to the present invention, the reproduced signal reproduced at the same time as the recording is differentiated, and the differentiated signal and the signal delayed for a predetermined time are added to obtain the added signal and the predetermined signal. By detecting the edge of the recording signal by comparing the positive and negative reference voltages, the edge of the recording signal can be accurately detected without being affected by the old information component or noise, and the reliability of verification is further enhanced. be able to.

When a reproduced signal reproduced at the same time as recording is differentiated and the differentiated signal is compared with a predetermined positive and negative reference voltage to detect the edge of the recorded signal, a predetermined time interval Δt is set. By detecting twice and further detecting the edge of the recording signal by taking the logical product, noise is included in the differential signal, and even if the edge is erroneously detected, the width within the time interval Δt when the logical product is obtained. Since the ones are removed as noise, the edge of the recording signal can be accurately detected regardless of the old information component and noise, and the reliability of verification can be further enhanced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an information recording apparatus of the present invention.

FIG. 2 is a circuit diagram showing a specific example of a verify signal reproducing circuit according to the embodiment of FIG.

FIG. 3 is a time chart showing the operation of the verify signal reproducing circuit of FIG.

FIG. 4 is a circuit diagram showing another embodiment of a verify signal reproducing circuit.

FIG. 5 is a circuit diagram showing still another embodiment of the verify signal reproducing circuit.

6 is a time chart showing the operation of the verify signal reproducing circuit of FIG.

FIG. 7 is a configuration diagram showing an information recording apparatus of a prior application example.

8 is a diagram showing signals of respective parts when the recording frequency ratio of old information and new information is overwritten with a recording frequency ratio of 4: 5 in the information recording apparatus of FIG.

9 is a diagram showing signals of respective parts when the information recording apparatus of FIG. 7 overwrites with a recording frequency ratio of old information and new information of 5: 4.

[Explanation of symbols]

 1 semiconductor laser 5 recording medium 6 magnetic head 10 optical sensor 11 differential amplifier 13 verify signal reproducing circuit 14 CPU 15 differentiating circuit 16 delay 17 adding circuit 18, 40, 41 positive comparator 19, 42, 43 negative comparator 20, 46 OR circuit 44,45 AND circuit

Claims (2)

[Claims] 1. An information recording apparatus for irradiating an information recording medium with a light beam to record information, and means for reproducing information currently recorded from reflected light of a recording light beam simultaneously with recording of information, and A differentiation circuit for differentiating the reproduction signal, an addition circuit for adding the differentiation signal of this differentiation circuit and a signal obtained by delaying this for a predetermined time, and the addition signal of this addition circuit with positive and negative predetermined reference voltages, respectively. A positive and negative comparator for binarizing and generating a signal corresponding to the rising edge and the falling edge of the recording signal is provided, and whether the recording signal is correctly recorded based on the output signals of the positive and negative comparators. An information recording apparatus characterized by performing verification at the same time as recording by judging. 2. An information recording apparatus for irradiating an information recording medium with a light beam to record information, and means for reproducing the currently recorded information from the reflected light of the recording light beam at the same time as recording the information, A differentiation circuit for differentiating the reproduction signal and the differentiation signal of this differentiation circuit with a predetermined positive reference voltage
Two positive comparators for binarizing and generating a signal corresponding to the rising edge of the recording signal, and binarizing the differential signal with a predetermined negative reference voltage to generate a signal corresponding to the falling edge of the recording signal. And a control circuit for controlling the two positive comparators and the two negative comparators to operate at predetermined time intervals, and each of the two positive comparators and the two negative comparators. An AND circuit for obtaining the logical product of the output signals is provided, and by verifying whether or not the recording signal is correctly recorded based on the output signal of the AND circuit, it is possible to perform verification at the same time as recording. Information recording device.