JPH08255346A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE: To provide a more exact verify signal by performing the substration between signals for verifies obtained from front and rear two optical spots for verifies of the optical spot for recording. CONSTITUTION: This device is provided with a semiconductor laser 21, a collimating lens 23, a diffraction grating 50, a quarter wave plate 27, an objective lens 28, a spherical lens 29, a cylindrical lens 30 and a hotodetector 31 and these optical elements are integrated as an optical head and an optical card 1 being an information recording medium is irradiated with plural light beams. The optical card 1 is mounted on a carriage (not shown in the figure) and the carriage is constituted so as to be reciprocatingly moved in an information track direction by a moving mechanism (not shown in the figure). Consequently, the optical head and the optical card 1 are reciprocatingly moved in the information direction relatively and since light beams reciprocatingly scan on an information track, information are recorded on the information track or recorded information are reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for optically recording or reproducing information on an information recording medium, and more particularly to a direct verify for reproducing recorded information at the same time as recording and verifying it. Is.

[0002]

2. Description of the Related Art Conventionally, various recording media such as disk-shaped, card-shaped and tape-shaped recording media are known for optically recording information or reproducing recorded information. Some of these information recording media can be recorded and reproduced, only can be reproduced. To record information on a recordable recording medium, information is recorded as an optically detectable information pit string by scanning an information track with a light beam in the form of a minute spot modulated according to the record information.

Further, when reproducing information from a recording medium, the information pit row of the information track is scanned with a light spot having a constant power such that recording is not performed on the recording medium and reflected light or transmitted light from the recording medium. Is detected and the recorded information is reproduced based on the obtained detection signal. The optical head used for recording and reproducing information on such a recording medium is configured to be movable relative to the recording medium in the information track direction and the direction crossing the track, and by the relative movement in both directions. A light spot is accessed to a desired information track and scanning is performed on the information track.

The optical head is provided with a focusing lens for focusing the light beam, and an objective lens is used as this lens. As such an objective lens,
The optical head main body is held so that it can be moved independently in the optical axis direction (focus direction) and the direction (tracking direction) orthogonal to the information track of the recording medium. Such holding of the objective lens is generally carried out via an elastic member, and movement of the objective lens in the focusing and tracking directions is generally driven by an actuator utilizing magnetic interaction.

FIG. 6 shows a schematic plan view of a write-once type optical card. On the information recording surface of the optical card 1, a number of information tracks 2 are arranged in parallel in the LF direction. A home position 3 is provided on the information recording surface of the optical card 1 as a reference position for accessing the information track 2. The information tracks 2 are arranged in the order of 2-1, 2-2, 2-3 ... From the side closer to the home position 3. In addition, as shown in FIG.
They are arranged as 1, 4-2, 4-3 .... These tracking tracks are used as guides for auto-tracking (hereinafter abbreviated as AT) that controls the light spot so as not to deviate from the target information track during scanning of the light spot during information recording / reproduction.

Such AT control causes a deviation (AT error) of the light spot from the information track in the optical head.
Is detected, and the detection information is controlled by a servo control circuit that negatively feeds back the detection information to a tracking actuator that drives the objective lens in the tracking direction. That is,
By moving the objective lens in the tracking direction (D direction) with respect to the main body of the optical head, the light spot is controlled so as not to deviate from the target information track.

Further, during information recording / reproduction, when the light spot is scanned on the information track, in order to make the light beam into a spot shape of an appropriate size on the surface of the optical card (focus), the objective lens is automatically moved. Focus (hereinafter AF
Abbreviated) control is performed. Such AF control is performed by the optical head in such a manner that the deviation of the light spot from the focused state (AF
Error) is detected, and this detection signal is negatively fed back to the focus actuator that moves the objective lens along the optical axis direction, and the objective lens is moved in the focus direction with respect to the optical head body, so that the optical spot becomes an optical card. It is controlled to focus on the surface (recording layer).

Here, in FIG. 7, S1, S2, S3
, S4, S5 indicate the light spots radiated on the information tracks of the optical card, of which the AT control is performed by using the light spots S1 and S5 which are partially applied to the tracking tracks 4-2, 4-3. Is done. In addition, AF control, creation of information pits during recording, and reading of information pits during reproduction are performed using the light spot of S3.
The information pit just after recording is verified by the light spots of 2 and S4. In the figure, 5-1 and 5-2 are information pits recorded in the light spot S3, and the information pits 5-
The reference numeral 1 denotes a recording by scanning the light spot in the L direction and the information pit 5-2 by scanning the light spot in the F direction.

FIG. 8 is a block diagram showing an optical information recording / reproducing apparatus using an optical card as an information recording / reproducing medium.
In FIG. 8, reference numeral 21 is a semiconductor laser as a light source, and here, 830n is polarized in a direction perpendicular to the information track.
It emits m-wavelength laser light. Reference numeral 23 is a collimator lens, 50 is a diffraction grating in which a grating is two-dimensionally arranged for splitting a light beam, and 26 is a polarization beam splitter. Further, 27 is a quarter wavelength plate, 28 is an objective lens,
29 is a spherical lens, 30 is a cylindrical lens, 31
Is a photodetector. The photodetector 31 includes four light receiving elements 31a, 31b, 31d, 31e and 4 as shown in FIG.
It is composed of one four-divided light receiving element 31c divided into two. Each of the above optical elements is integrated as an optical head so that a desired information track of the optical card 1 can be accessed. 61 is a laser driver (hereinafter,
62 is an MPU.

Here, when information is recorded on the optical card 1 by the optical head, the LD is used in accordance with the recording command from the MPU 62.
A recording level current is injected into the semiconductor laser 21 by the driver 61. When reproducing information, MP
According to the reproduction command from U62, the LD driver 61 injects a reproduction level current into the semiconductor laser 21. In this way, the semiconductor laser 21 is driven, and the semiconductor laser 21
The light beam emitted from the light source becomes a divergent light beam and enters the collimator lens 23. Then, the collimator lens 2
After being collimated by 3, the light is incident on the two-dimensional diffraction grating 50, and is divided into five effective light beams (zero-order diffraction light and two-direction ± 1st-order diffraction light) by the diffraction grating 50.

The five divided light beams are incident on the polarization beam splitter 26 as P-polarized light beams, transmitted therethrough, and are incident on the ¼ wavelength plate 27, and the ¼ wavelength plate 2
It is converted into circularly polarized light when passing through 7. The five light beams converted into circularly polarized light are focused into a minute light spot by the objective lens 28 and focused on the optical card 1. The focused light is the minute light spots S1 and S2 (+ 1st-order diffracted light), S3 (0th-order diffracted light), S4 and S5 (-1st-order diffracted light) shown in FIG. The light spot S3 is used for recording, reproduction and AF control as described above, S1 and S5 are used for AT control, and S2 and S4 are used for verification.

As shown in FIG. 7, the spot positions on the optical card 1 are such that the optical spots S1 and S5 are located on the adjacent tracking tracks, and the spots S2, S3 and S4 are located on the information track 2 between the tracking tracks. positioned. Also, verify light spots S2 and S
4 is located before and after the light spot S3. In this way, a light spot is irradiated on the optical card 1, and a part of the light spot is reflected on the card surface and enters the objective lens 28. This reflected light passes through the objective lens 28 again to become a parallel light beam, and further 1 /
By passing through the four-wave plate 27, it is converted into a light beam whose polarization direction is rotated by 90 ° from that at the time of incidence. Then, it is incident on the polarization beam splitter 26 as an S-polarized beam, reflected by the detection optical system side due to its characteristics, and separated from the incident light beam from the semiconductor laser 21.

The detection optical system comprises a spherical lens 29, a cylindrical lens 30, and a photodetector 31, and a combination of the spherical lens 29 and the cylindrical lens 30 performs AF control by the astigmatism method. Further, the five light fluxes reflected from the optical card 1 are detected by the photodetector 31 composed of a plurality of light receiving elements. The light reception signals of the plurality of light receiving elements of the photodetector 31 are recorded / reproduced by the gain switching circuit 6
Sent to 5. The recording / reproducing gain switching circuit 65 is a circuit for correcting the fluctuation of the signal level of each light receiving element caused by the modulation of the recording light spot, that is, the change of the recording power and the reproducing power, and keeping it at a substantially constant signal level. .
That is, the gain for amplifying the signal is switched according to the recording / reproducing gain switching signal output from the MPU 62, and the signal of each light receiving element is maintained at a constant signal level.

The output signal of the recording / reproducing gain switching circuit 65 is sent to the adding / subtracting circuit 63, the subtracting circuit 64, and the selection switch 66. In the addition and subtraction circuit 63, an AF control signal (focus error signal),
And an information reproduction signal, and an AT control signal (tracking error signal) is generated in the subtraction circuit 64.
It is sent to U62. As will be described later, the selection switch 66 selects a verification signal according to a movement direction signal (a signal indicating the scanning direction of the light spot) from the MPU 62.

In the MPU 62, the AF control signal, A
A focus actuator and a tracking actuator (not shown) are driven based on the T control signal to displace the objective lens 28 in the focus direction and the tracking direction, thereby performing focus control and tracking control. Further, at the time of reproducing information, the MPU 62 subjects the information reproducing signal to predetermined signal processing to generate reproduced data, and at the time of recording information, recording is performed by using the verifying signal selected by the selection switch 66. Simultaneous verification, that is, direct verification is performed.

FIG. 9 is a circuit diagram showing in detail the signal processing circuit of the above optical card information recording / reproducing apparatus. In FIG. 9, 31 is the photodetector shown in FIG.
a, 31b, 31d, 31e and a four-divided light receiving element 31c
It consists of The light spot on the light receiving surface of each light receiving element shows the reflected light of the light spot in FIG. The reflected light from the AT control light spots S1 and S5 is received by the light receiving elements 31a and 31a.
The reflected light of the light spot S3 for AF control, recording, and reproduction is received by e and is received by the four-division light receiving element 31c.
The reflected light from the verifying light spots S2 and S4 is received by the light receiving elements 31b and 31d, respectively.

The output signals of the light receiving elements 31a to 31e of the photodetector 31 are output to the gain switching circuits 101 to 108 of the recording / reproducing gain switching circuit 65. That is, the recording / reproducing gain switching circuit 65 is composed of eight gain switching circuits 101 to 108. The output signal of the light receiving element 31a is the gain switching circuit 101, and the output signal of the light receiving element 31b is the gain switching circuits 102, 4 respectively. The output signals of the four light receiving element pieces of the divided light receiving element 31c are gain switching circuits 103 to 1
It is output to 06 respectively. The output signal of the light receiving element 31d is output to the gain switching circuit 107, and the output signal of the light receiving element 31e is output to the gain switching circuit 108. These gain switching circuits 101 to 108 switch the gain for amplifying the signal in accordance with the modulation of the recording power and the reproducing power of the semiconductor laser 21 as described above, and the output signals of the respective light receiving elements 31a to 31e are A constant signal level is maintained by the gain switching operation of each gain switching circuit.

The output signals of the gain switching circuits 101 and 108 are output to the subtraction circuit 64, and the subtraction circuit 64 detects the difference between them to generate an AT control signal. In addition, the gain switching circuits 103 to 106 are provided in the 4-division light receiving element 31c.
Although it corresponds to one light receiving element piece, the light receiving element 31
The output signals of the gain switching circuits 103 and 105 corresponding to the light receiving element pieces in the diagonal direction of c, and the gain switching circuit 10.
The output signals of 4 and 106 are addition circuits 117 and 11 respectively.
8 is added. The subtraction circuit 120 detects the difference between the output signals of the adder circuits 117 and 118, and outputs the AF control signal. The output signals of the adder circuits 117 and 118 are
Further, the light is added by the addition circuit 121, and the four-division light receiving element 31c
Is generated. This sum signal is output as an information reproduction signal. The adder circuits 117 and 118, the subtracter circuit 120, and the adder circuit 121 are the adder and subtracter circuit 63 of FIG.
It corresponds to.

The output signals of the gain switching circuits 102 and 107 are output to the selection switch 66, and one of the DV (direct verify) signals is selectively output according to the movement direction signal from the MPU 62. Specifically,
As shown in FIG. 7, when the scanning direction of the light spot is the F direction, the selection switch 66 is connected to the F side, and the light receiving element 31d
The signal on the side is output to the MPU 62 as a verification signal. On the other hand, if the scanning direction of the light spot is the L direction, the selection switch 66 is connected to the L side, and the signal on the light receiving element 31b side is output to the MPU 62 as a verification signal. In other words, since the verifying light spots S2 and S4 are applied to both sides of the recording light spot S3, if the scanning direction of the optical spot changes between the forward path and the return path of the optical card 1, the recording light spot is correspondingly changed. The verification signal reproduced by the light spot scanned after the spot is selected. The MPU 62 uses the verifying signal selected as described above to perform verifying at the same time as recording.

[0020]

By the way, in the past, not only the optical card but also the optical recording medium is provided with the protective layer such as transparent resin or glass on the recording layer. There is a finite distance between the layer surfaces. Generally, since the recording layer surface and the light receiving surface of the photodetector are arranged at substantially conjugate positions, the reflected light from the recording layer is focused as a focused light spot on the light receiving surface of the photodetector, but from the surface of the optical card. The reflected light of is incident on the light receiving surface of the photodetector as a defocused image so as to cover the focused light spot. Therefore, the reflected light of the recording light spot from the surface of the optical card spreads on the light receiving surface of the photodetector and leaks into the light receiving element for verification. Naturally, since the reflected light from the optical card surface of the recording light spot is intensity-modulated, not only the modulation component due to the information pit but also the modulation component is incident on the light receiving element for verification.

This situation will be described with reference to FIG. FIG. 10A is a modulation waveform of the recording light spot, and FIG.
(B) is a verification light-receiving element 31b (or 31d)
2 is a signal waveform in which a signal due to the verifying light spot and the signal component due to the light reflected from the optical card surface are added. Further, FIG. 10C shows the verifying signal waveform of only the modulation component due to the information pit. That is, FIG.
It is a pure verifying signal in which the modulation components of the recording power and the reproduction power as shown in (a) are removed by the gain switching described above, and the components due to the reflected light from the surface of the optical card are removed. When this is binarized, FIG.
As described above, the binarized signal corresponds to the recording signal.

However, in actuality, at the time of recording information, not only the modulation component due to the information pit but also the signal component due to the reflected light from the surface of the optical card which has been subjected to the power modulation as described above are included, so that for verifying. Signal of Figure 1
The signal waveform is 0 (d). Therefore, if this is binarized at a predetermined slice level, it becomes a binarized signal as shown in FIG. 10E, and the information signal width corresponding to the information pit becomes narrow due to the influence of the signal component due to the reflected light from the optical card surface. Will end up. Therefore, when the signal component due to the reflected light from the surface of the optical card becomes large, the information signal width of the information pit of the binarized signal becomes narrower accordingly, so that a verification error occurs even if the information can be recorded correctly,
There was a risk of making an incorrect verify.

In view of the above-mentioned conventional problems, the present invention eliminates the signal component due to the reflected light from the surface of the recording medium included in the verifying signal, and makes it possible to perform verifying at the same time as recording with high reliability. It is an object of the present invention to provide a static information recording / reproducing device.

[0024]

SUMMARY OF THE INVENTION An object of the present invention is to provide an information recording apparatus for recording information by scanning a recording light spot modulated according to an information signal on an information track of an information recording medium. The recording light spot on the information track of the information recording medium, a first verifying light spot at a position preceding the recording light spot, and a second verifying light at a position subsequent to the recording light spot. A light beam irradiating means for irradiating a light spot for use, and 2 reproduced by the first and second verify light spots.
Gain switching means for switching the gains of two signals corresponding to the modulation of the recording light spot, subtraction means for subtracting the gain-switched signals output from the gain switching means, and the subtraction means It is achieved by an optical information recording / reproducing apparatus characterized in that it has a verifying means for performing verifying at the same time as recording using the verifying signal obtained by the means.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the optical information recording / reproducing apparatus of the present invention. In FIG. 1, the same parts as those of the conventional device of FIG. 8 are designated by the same reference numerals. In FIG. 1, first, a semiconductor laser 21, a collimator lens 23,
The diffraction grating 50, the polarization beam splitter 26, the quarter-wave plate 27, the objective lens 28, the spherical lens 29, the cylindrical lens 30, and the photodetector 31 are all the same as those in FIG. These optical elements are integrated as an optical head to irradiate the optical card 1 as an information recording medium with a plurality of light beams. The optical card 1 is mounted on a carriage (not shown), and the carriage is configured to reciprocate in the information track direction by a moving mechanism (not shown). As a result, the optical head and the optical card 1 relatively move back and forth in the information track direction, and the light beam from the optical head reciprocally scans the information track to record or reproduce information on the information track. It is supposed to do.

The LD driver 61, MPU 62, addition and subtraction circuit 63, subtraction circuit 64, and recording / reproduction gain switching circuit 65 are the same as those shown in FIG. The recording / reproducing gain switching circuit 65 corresponds to the modulation of the recording power and the reproducing power of the semiconductor laser 21 with the gain for amplifying each signal of the light receiving elements 31a to 31e of the photodetector 31 at the time of recording information. It is a circuit for switching. Recording / playback gain switching circuit 65
The output signals of the gain switching circuits 101 to 108 are sent to the addition / subtraction circuit 63, the subtraction circuit 64, etc. in the subsequent stage.

Further, in the present embodiment, the subtraction circuit 68 is provided at the subsequent stage of the recording / reproduction gain switching circuit 65, and the verification signal among the output signals of the recording / reproduction gain switching circuit 65 is output to the subtraction circuit 68. Has been done. Subtraction circuit 6
8, the two signals of the gain switching circuits 102 and 107 for switching the gain of the verification signal in the recording / reproducing gain switching circuit 65 are subtracted, as will be described later in detail.
It serves to remove the signal component contained in the verification signal due to the reflected light from the surface of the optical card.

The MPU 62 is a microprocessor for controlling each part in the apparatus, and the LD driver 61 is an MP.
The semiconductor laser 21 is driven under the control of U62.
That is, when the information is reproduced, the semiconductor laser 21 is driven so that the optical output becomes the reproduction power, and when the information is recorded, the optical output of the semiconductor laser 21 is modulated into the recording power and the reproduction power according to the information signal. The adder / subtractor circuit 63 generates an AF control signal based on the light reception signal of the photodetector 31 as described above, and the subtraction circuit 64 generates an AT control signal based on the light reception signal of the photodetector 31. The AF control signal is detected by the astigmatism method, and the AT control signal is detected by the three-beam method. AF control signal and AT control signal are MPU6
2, and the MPU 62 performs focus control and tracking control based on those control signals. In addition, at the time of reproducing information, the adder / subtractor circuit 63 generates a summation signal (information reproduction signal) of the four-division light receiving element 31c of the photodetector 31. The MPU 62 uses the obtained information reproduction signal to perform predetermined signal processing to generate reproduction data.

FIG. 2 is a circuit diagram showing in detail the signal processing circuit of the above embodiment. 2, the same parts as those of the conventional signal processing circuit of FIG. 9 are designated by the same reference numerals. In FIG. 2, reference numerals 31a to 31e are light receiving elements that constitute the photodetector 31. Also in this embodiment, the light beam of the semiconductor laser 21 is divided into five light beams, and these light beams are irradiated onto the information track of the optical card 1 as light spots S1 to S5 as shown in FIG. The light spot on each light receiving element in FIG. 2 represents the reflected light of the light spot in FIG. The reflected light from the AT control light spots S1 and S5 is received by the light receiving elements 31a and 31e, and the reflected light from the verify light spots S2 and S4 is received by the light receiving elements 31b and 31d. The reflected light of the AF control, recording, and reproduction light spots S3 is received by the four-divided light receiving element 31c.

The recording / reproducing gain switching circuit 65 is composed of eight gain switching circuits 101 to 108 as in FIG. 9, and the gain switching circuits 101, 108 and 4 are provided to the outputs of the AT control light receiving elements 31a and 31e. Divided light receiving element 31c
Each of the four light receiving element pieces of
06 is provided. Further, the gain switching circuits 102, 10 are provided to the outputs of the verification light receiving elements 31b and 31d.
7 is provided, and these gain switching circuits 102 and 107 are provided.
Is output to the subtraction circuit 68. The specific configuration of the subtraction circuit 68 will be described later in detail.

The subtraction circuit 64 generates an AT control signal by detecting the difference between the output signals of the gain switching circuits 101 and 108. Further, the gain switching circuits 103 and 10 corresponding to the light-receiving element pieces of the four-divided light-receiving element 31c which are diagonal to each other.
5 and the output signals of the gain switching circuits 104 and 106 are added by adders 117 and 118, respectively. Then, the subtraction circuit 120 detects the difference between the addition signals to generate an AF control signal, and the addition circuit 121 further adds the addition signals, whereby the four-division light receiving element 3
A sum signal of 1c is generated. This sum signal is output as an information reproduction signal. The adder circuits 117 and 118, the subtractor circuit 120, and the adder circuit 121 correspond to the adder and subtracter circuit 63 of FIG.

FIG. 3 is a block diagram showing a concrete example of the subtraction circuit 68. In FIG. 3, 68a and 68b are subtraction circuits, respectively, and SW1 is a subtraction circuit 68 according to a movement direction signal output from the MPU 62 and indicating the scanning direction of the light spot.
A selection switch for selecting one of a and 68b. The output signals of the gain switching circuits 102 and 107 of FIG. 2 are input to the subtraction circuits 68a and 68b, respectively. Here, the output signal of the gain switching circuit 102 corresponding to the verification light receiving element 31b is shown as A, and the output signal of the gain switching circuit 107 corresponding to the verification light receiving element 31d is shown as B, and (A- in the subtraction circuit 68a.
B), the subtraction circuit 68b subtracts (B-A). The selection switch SW1 is switched according to the scanning direction of the light spot, and outputs the output signal of one subtraction circuit to the MPU 62.

In this embodiment, two subtraction circuits 68a and 6a are used.
When selecting one of the 8b output signals,
The output signal of the subtraction circuit for subtracting the signal reproduced by the preceding verifying light spot from the signal reproduced by the verifying light spot following the recording light spot is selectively output. That is, as shown in FIG. 7, when the scanning direction of the light spot is the F direction, that is, when the verifying light spot S2 precedes the recording light spot S3 and the verifying light spot S4 follows, the selection switch SW1 is turned on. It is connected to the F side and selects the output signal of the subtraction circuit 68b. On the other hand, the scanning direction of the light spot is the L direction, that is, the verifying light spot S4 precedes the recording light spot S3,
When the verifying light spot S2 follows, the selection switch SW1 is connected to the L side and selects the output signal of the subtraction circuit 68a.

Next, the operation of this embodiment will be described in detail with reference to FIG. At the time of recording information, the reflected light of the light spots other than the reflected light spots S2 and S4 for the verification is incident on the verification light receiving elements 31b and 31d of the photodetector 31, and in particular as described above. It is assumed that the reflected light of the recording light spot S3 reflected in the defocused state from the surface of the optical card is incident. Here, the signal level due to the reflected light of the recording light spot from the surface of the optical card is I ₀ , the signal level due to the reflected light of the verifying light spot is I ₁ , the power modulation degree of the semiconductor laser at the time of recording is W, Let P be the degree of modulation due to pits.

Further, when recording information, it is assumed that five light spots are scanned on the information track of the optical card 1 as shown in FIG. 7 to record information and verify at the same time as recording. FIG. 4A shows an output signal of the verifying light receiving element 31b (or 31d) for detecting the verifying light spot preceding the recording light spot at this time. At the time of recording information, the light beam of the semiconductor laser 21 is modulated according to the information signal, and the signal component reflected in the defocused state of the recording light spot from the surface of the optical card also enters the verification light receiving element. Therefore, as shown in FIG. 4A, the output signal of the verification light receiving element on the leading side is obtained by adding the signal component due to the reflected light from the modulated optical card surface and the signal component due to the reflected light from the verifying light spot. , (I ₀ + I ₁ ) W. That is, since the verifying light spot on the leading side always scans the unrecorded information track, the signal of the verifying light receiving element is
It is the sum of the verify signal component that is not modulated by the information pit and the signal component that is power modulated by the reflected light from the optical card surface.

FIG. 4 (c) shows an output signal of the verifying light receiving element for detecting the reflected light of the verifying light spot that follows the recording light spot. Since the following verifying light spot scans on the information pit immediately after being recorded by the recording light spot, the output signal of the verifying light receiving element on the following side further exceeds the signal on the preceding side. The signal waveform includes a modulation component due to the information pit, and becomes (I ₀ + I ₁ · P) W as shown in FIG.
The signal of FIG. 4A and the signal of FIG. 4C are output to the subtracting circuit 68, and the preceding verify signal is subtracted from the subsequent verify signal as described above. That is, depending on the scanning direction of the light spot by the MPU 62, 2
By selecting one of the two subtraction circuits 68a and 68b, the preceding signal is subtracted from the following signal. Here, when the preceding signal is subtracted from the following signal, the subtraction value X is X = (I ₀ + I ₁ · P) W / (I ₀ + I ₁ ) W = I ₁ (P-1 ) W ... (1) The signal after this subtraction is shown in FIG.
However, in reality, the gain is switched by the recording / reproducing gain switching circuit 65, and it may be considered that W = 1.
Becomes X = I ₁ (P-1) (2). This signal is used as a verification signal by the MPU 62.
And is binarized as shown in FIG. MPU
At 62, the obtained binarized signal is compared with the recording signal to perform verification at the same time as recording. When the recording of the information track in one direction is completed, the MPU 62 selects the selection switch S
W1 is switched to select a subtraction circuit corresponding to the scanning direction of the light spot, and information recording and verification are similarly performed.

In this embodiment, as is clear from the equation (2), the verification signal component does not include the signal component I ₀ due to the reflected light from the optical card surface, and unnecessary reflection from the optical card surface occurs. The signal component I ₀ due to light can be removed. Therefore, since unnecessary signal components due to the reflected light from the surface of the optical card can be removed, the information signal width corresponding to the information pits of the binarized signal does not fluctuate when binarizing the verification signal. It is possible to accurately obtain a binarized signal in which the information pit is reproduced.

Next, another embodiment of the subtraction circuit 68 will be described. FIG. 5 is a circuit diagram showing the subtraction circuit 68 of this embodiment. In the present embodiment, the subtraction circuit 68 includes one subtraction circuit 68c and two selection switches SW2 and SW3, and is configured to switch and control the two selection switches SW2 and SW3 according to the scanning direction of the light spot. ing. More specifically, first, when the light spot scans in the F direction as shown in FIG. 7, the selection switches SW2 and SW3 are respectively connected to the F side by a movement direction signal from the MPU 62, and a signal from the light receiving element 31b. Is input to the y terminal of the subtraction circuit 68c, and the signal from the light receiving element 31d is input to the x terminal of the subtraction circuit 68c.

The subtraction circuit 68c converts the input signal from the x terminal to y
The input signal of the terminal is subtracted, and the light receiving element 3
When the signal from 1b is A and the signal from the light receiving element 31d is B, the subtracted value of (BA) is output to the MPU 62 as a direct verify signal. That is, when the light spot scans in the F direction, the verify light spot S2 precedes the recording light spot S3 and the verify light spot S4 follows, as shown in FIG. The signal A of the light receiving element 31b that receives the reflected light of the light spot S2 is subtracted from the signal B of the light receiving element 31d that receives the reflected light of S4, and the signal on the leading side is subtracted from the signal of the subsequent example.

On the other hand, when the scanning direction of the light spot is the L direction, the selection switches SW2 and SW3 are respectively connected to the L side, and the signal on the light receiving element 31b side is subtracted from the subtraction circuit 68c.
The signal on the light receiving element 31d side is input to the y terminal of the x terminal. Therefore, in this case, the subtraction circuit 68c subtracts the signal B on the light receiving element 31d side from the signal A on the light receiving element 31b side, and outputs the value (AB) to the MPU 62 as a direct verify signal. That is, when the light spot scans in the L direction, as shown in FIG. 7, the light spot S4 precedes and the light spot S2 follows, so that the light receiving element 31b that receives the reflected light of the light spot S2 receives light. The signal B of the light receiving element 31d that receives the reflected light of the light spot S4 is subtracted from the signal A, and the signal of the leading side is also subtracted from the signal of the following side.

In this way, by switching the two selection switches SW2 and SW3 in accordance with the scanning direction of the light spot and exchanging the signals input to the subtraction circuit 68c on the leading side and the trailing side, the optical card is the same as in FIG. It is possible to control so that the signal on the leading side is always subtracted from the signal on the trailing side in the forward path and the backward path. Since the subtraction circuit is usually more expensive than the selection switch, only one subtraction circuit is required in this embodiment, and the device can be manufactured at a lower cost than that shown in FIG.

In the above embodiments, the one-light source type device in which the light beam of one semiconductor laser is divided into a plurality of light beams and used for information recording, reproduction, AF and AT control, and verification is used as an example. However, the present invention is not limited to this, and can be applied to a multiple light source system in which other light sources for recording and verifying are independently provided. That is, even in the multiple light source system, the recording light spot reflected from the surface of the optical card is incident on the light receiving element for verification in a defocused state. The signal component due to the reflected light can be removed.

More specifically, in the case of the multiple light source system, the signal by the verifying light spot preceding the recording light spot is (I ₀ W + I ₁ ), and the signal by the following verifying light spot is (I ₀ W + I ₁ ). The signal is (I ₀ W + I ₁
P), and when the preceding signal is subtracted from the following signal, the subtraction value X is X = (I ₀ W + I ₁ P) − (I ₀ W + I ₁ ) = I ₁ (P−1) ... (3) Therefore, it becomes exactly the same as the expression (2) in the case of the single light source method, and the unnecessary signal component due to the reflected light from the surface of the optical card can be removed.

In the embodiment, the preceding signal is subtracted from the following signal, but the following signal may be subtracted from the preceding signal. The subtracted value X ′ in this case becomes I ₁ (1-P),
Similarly, the signal component due to the reflected light from the surface of the optical card can be removed. However, since the verification signal at this time has a negative polarity (a signal waveform in which the signal of FIG. 4C is symmetrical with respect to the 0 level), the slice level is set to be negative when binarizing it. Or, it is necessary to invert to the positive polarity.

Further, in the embodiment, the device using the optical card is taken as an example, but it can be applied to the device using the optical disk or the magneto-optical disk, in which case the scanning direction of the light spot is uniform. Since it is in the direction, only one subtraction circuit is required, and switching of the subtraction circuit by the selection switch or switching of the input signal to the subtraction circuit is unnecessary. This also applies to the case where information is recorded by scanning the light spot in only one direction in the optical card. Of course, in such a case, the signal on the leading side may be subtracted from the signal on the trailing side, or vice versa.

Further, in the embodiment, the subtraction circuit for subtracting the verify signal may be operated at all times regardless of the recording / reproducing operation of the apparatus, but it is stopped from the MPU except during the recording operation which does not require the verification. It is desirable to output the instruction and stop the subtraction operation. That is, when the recording operation is not performed, the verify signal is sent to the MPU,
Since U performs unnecessary processing and loses time for information processing such as reproduction, it is preferable to stop the operation except during the recording operation in which verification is not performed.

[0047]

As described above, according to the present invention, the verification signals obtained by the two verification light spots before and after the recording light spot are subtracted from each other to thereby perform the recording included in the verification signal. There is an effect that an unnecessary signal component due to the reflected light from the medium surface can be removed, and as a result, a more accurate verify signal can be obtained, and verify can be performed simultaneously with recording with high reliability.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing in detail the signal processing circuit of the embodiment of FIG.

FIG. 3 is a circuit diagram showing a specific example of a subtraction circuit of the embodiment of FIG.

FIG. 4 is a diagram showing signals of respective parts of the embodiment of FIG.

FIG. 5 is a circuit diagram showing another example of a subtraction circuit 68.

FIG. 6 is a diagram showing a recording surface of an optical card.

FIG. 7 is a diagram showing how five light spots are scanned on an information track of an optical card.

FIG. 8 is a block diagram showing a conventional optical card information recording / reproducing apparatus.

9 is a circuit diagram showing in detail a signal processing circuit of the device of FIG.

FIG. 10 is a diagram for explaining a problem of the device of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical card 2 Information track 21 Semiconductor laser 28 Objective lens 31 Photodetector 31a-31e Light receiving element 50 Diffraction grating 61 LD driver 62 MPU 63 Addition and subtraction circuit 64 Subtraction circuit 65 Recording / reproduction gain switching circuit 68 Subtraction circuit 68a, 68b, 68c Subtraction circuit 101-108 Gain switching circuit SW1, SW2, SW3 selection switch

Claims (4)

[Claims] 1. An information recording apparatus for recording information by scanning a recording light spot modulated according to an information signal on an information track of an information recording medium, wherein the recording is performed on the information track of the information recording medium. Light spot, and a light beam for irradiating a first verifying light spot at a position preceding the recording light spot and a second verifying light spot at a position following the recording light spot. From the irradiation means, the gain switching means for switching the gains of the two signals reproduced by the first and second verifying light spots respectively corresponding to the modulation of the recording light spot, and from the gain switching means The subtraction means for subtracting the output signals after the gain switching and the verification signal obtained by the subtraction means are used to perform verification at the same time as recording. An optical information recording / reproducing apparatus having a verifying means for 2. The optical information recording / reproducing apparatus according to claim 1, wherein the subtracting means reproduces from a signal reproduced by a second verifying light spot following the recording light spot. An optical information recording / reproducing apparatus for subtracting a signal reproduced by a preceding first verifying light spot. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the light beam irradiation means is a single light source,
A diffraction grating for dividing the light beam of the light source into a plurality of light beams, and irradiating the divided light beam as a recording light spot and first and second verifying light spots. A characteristic optical information recording / reproducing apparatus. 4. The optical information recording / reproducing apparatus according to claim 1, wherein the light beam irradiating means includes a light source for irradiating a recording light spot and first and second verifying light spots. An optical information recording / reproducing apparatus including a light source for irradiating, and irradiating a recording light spot and first and second verifying light spots independently of each light source.