JP2625528B2 - Optical information recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention records information on an optical information recording medium,
The present invention relates to an optical information recording / reproducing apparatus capable of reproducing information recorded on a medium and / or erasing information recorded on the medium, and in particular, an optical element capable of detecting an abnormality at the time of auto-focusing and / or auto-tracking. Information recording and reproducing apparatus.

(Prior Art) An information recording medium used in an optical information recording / reproducing apparatus for recording information using light or reading recorded information is in the form of a disk, card, tape or the like. It has been known. Among them, the card-shaped information recording medium is generally small and weighed, is easy to carry, and is expected to be in great demand as a relatively large-capacity information recording medium.

FIG. 5 schematically shows such a card-shaped information recording medium (hereinafter referred to as an “optical card”) 101.
In the information recording area 102, information tracks 103 are arranged in parallel.
Is formed. In addition, a track selection area for an address and a track selection area ahead of a jump are provided at a front part and a rear part of the information track 103.
A home position 105 of the light beam spot is formed outside the information recording area 102.

In the information track of the optical card 101, an optically detectable recording bit string is recorded as information by scanning a light beam spot modulated according to recording information and narrowed down to a minute spot. At this time, in order to record information accurately without causing troubles such as a light beam spot crossing an information track, the irradiation position of the light beam spot must be set in a direction orthogonal to the scanning direction in the plane of the optical card. (Auto tracking, hereinafter referred to as "AT"). In addition, control is performed in the direction perpendicular to the optical card surface in order to irradiate the light beam as a small spot with a stable size despite the bending of the optical card and mechanical errors (auto focusing, hereinafter referred to as "AF") There is a need. The above AT and AF are required at the time of reproduction and erasing.

FIG. 6 is a block diagram of an apparatus for recording and reproducing information on and from such an optical card. Reference numeral 106 denotes a motor for driving the optical card 101 in the direction of the arrow in the figure. An optical head 121 includes a light source 107 such as a semiconductor laser. The light emitted from the optical head is collimated by a collimator lens 108 to form a beam splitter 109.
The light is condensed on a recording track of the optical card 101 by the objective lens 110 through the optical disk 101. Further, the light reflected on the recording track is transmitted through the beam splitter 109, is divided into two by the next beam splitter 109, and is divided into two by a condensing lens 11 respectively.
The light is condensed on the photoelectric conversion element 115 for tracking signal detection and on the photoelectric conversion element 116 for focusing signal detection by 3,114. The signals obtained by the photoelectric conversion elements 115 and 116 are supplied to a tracking control circuit 117 and a focusing control circuit 118, respectively. The optical head 121 is provided with an objective lens 110 and a tracking coil 111 for operating in a direction orthogonal to the information track along the optical card surface.
A focusing coil 112 for operating the objective lens 110 in a direction perpendicular to the optical card surface is provided, and a control circuit 11 is provided based on the tracking signal and the focusing signal detected by the photoelectric conversion elements 115 and 116.
Tracking coil 1 by command from 7,118
The AT and the AF are performed by moving the objective lens 110 by supplying a current to the focusing coil 11 and the focusing coil 112.

In the figure, reference numeral 119 denotes a system controller for controlling the optical recording / reproducing device, which sends out control signals to the motors 106 and 122 or the tracking control circuit 117 and the focusing control circuit 118 via the bus 120. here,
The motor 122 is for moving the optical head 121 in the direction u in FIG.

(Problems to be Solved by the Invention) In such an optical information recording / reproducing apparatus, when information is stored or reproduced, AT control may be deviated due to an external impact or a defect of the record carrier itself. is there. In particular, during recording, the light beam spot deviates from the track to be recorded, moves in a direction crossing it, for example, enters an adjacent recorded track, and superimposes new information on the information recorded here. Recording.

The present applicant has proposed an optical information recording / reproducing apparatus which detects a tracking error by detecting a relative speed between an objective lens and an optical head when the relative speed exceeds a predetermined value. In this case, a sufficient effect can be expected when the speed of the objective lens is lost when the AT control is lost, but it is difficult to detect abnormal tracking when the speed of the objective lens is very low when the AT control is lost. It involves the problem of being.

In addition, the present applicant separately stores a tracking error signal including an eccentric state in advance and, based on the stored data, proposes an optical information recording / reproducing apparatus for detecting a tracking abnormality earlier. I have. Here, an averaging process is performed on a plurality of tracks in order to reduce the influence of a medium defect specific to each track.

(Object of the Invention) The present invention has been made based on the above circumstances, and before performing recording or reproduction on a record carrier, records the objective lens position for one track in advance, and based on the result, records or reproduces the data. It is an object of the present invention to provide an optical information recording / reproducing apparatus which detects a tracking error during reproduction.

(Means for Solving the Problems) Therefore, in the present invention, the light beam spot formed by the condensing means of the optical head is formed along a plurality of information tracks formed in parallel on a card-shaped recording medium. An optical information recording / reproducing apparatus for recording and / or reproducing information by reciprocating scanning, wherein a means for detecting a relative position between the condensing means and the optical head with respect to a direction of the parallel arrangement of the information tracks; Means for storing the detected relative position value for one track; means for comparing the stored relative position value with the detected relative position; and, as a result of the comparison, the stored relative position value Means for detecting that tracking or focusing control is lost when the difference between the value and the detected relative position is equal to or more than a predetermined amount, and stores the value of the relative position. When the scanning direction of the light beam spot is in the opposite direction between the time when the comparison is performed and the time when the comparison is performed, the comparison unit determines the value obtained by reversing the order of the relative position values stored in the storage unit and the value. The comparison with the detected relative position is performed.

(Operation) Therefore, the position of the objective lens with respect to the optical head is 1
Since the data for the tracks is stored, even if the speed of the objective lens when the AT control is deviated is extremely low, the abnormality can be reliably detected because the position of the objective lens is compared in the scanning process. Further, even when noise appears in the tracking error signal due to a medium defect, detection is performed at the position of the objective lens position. Therefore, it is not necessary to perform averaging processing in a plurality of scans, and high-speed operation of the apparatus can be realized.

(Embodiment) An embodiment of the present invention will be specifically described below with reference to FIGS. 1 to 3. In the figure, reference numeral 1 denotes a relative position in the u direction between the objective lens 110 and the optical head 121 (the fifth position)
The output signal a of the position sensor is supplied to the subtracter 2, and the output signal c of the subtracter 2 is supplied to the window comparator 3 and the AD converter 4, and the output signal d is output from the window comparator 3. However, the output signal e is supplied from the AD converter 4 to the system controller 119, respectively. Also, the system controller 1
19 outputs an output signal f to the DA converter 5, and the DA converter 5 supplies the signal b to the subtractor 2 as a negative signal.

In such a configuration, when recording is performed on the optical card 101, the optical head 121 operates the objective lens 110 to perform AF and AT. In this case, when the tracking, the optical card one track, moving the light beam spot moves from x ₁ in FIG. 5 to x _4. At this time,
The skew between the direction of the information track of the optical card 101 and the moving direction of the optical card changes the relative position between the objective lens 110 and the optical head 121. As a result, the output signal a of the position sensor 1 changes as shown in FIG. To change. At this time, the signal b to the subtractor 2 is transmitted to the system controller 119.
Since the output signal from is equal to 0, it is also 0, and is constant as shown in FIG. Therefore, the output signal c from the subtractor 2 changes equivalently to the signal a. The signal c is converted into a digital signal e by the AD converter 4 and input to the system controller 119. The above system controller 119
Then, the digital signal e is stored in a predetermined memory.

Then, when performing the actual recording, (see FIG. 3) when moving the light beam spot from x ₁ to x _2, from inside the system controller 119 outputs the stored contents of the-out before the memory by the digital signal f I do. The signal f is a DA converter 5
The output signal b is equivalent to the signal a described above. The output signal a of the position sensor 1 is x ₃
Is equivalent to the signal b, the subtractor 2
Is zero. Then, whether there is a defect in an impact is applied or an optical card 101 from the outside at the position of x _3, the AT control is started off. The difference between the signals a and b in this case is increased, the signal c becomes gradually larger, the signal c becomes + [Delta] V at the position of x _4.

On the other hand, the window comparator 3 sends the abnormality detection signal d when the signal c is larger than + ΔV or smaller than −ΔV.
If there is the edge of the AT control, the abnormality detection signal d is sent to the system controller 119 at the position x _4. Upon receiving the signal d, the system controller 119 reduces the light source 107 from the recording power to the non-recording power, thereby avoiding writing to the adjacent information track when the AT control is released. In this way, multiple recording is prevented. Note that the window comparator abnormality detection signal Δ
The value of V is preferably set to a value equal to or smaller than the track pitch of the information track 103.

In the embodiment shown in FIG. 1, the subtractor 2, the window comparator 3, the DA converter, and the like are used. However, such a hardware part is omitted, and a software part in the system controller 119 performs subtraction, comparison, and the like. A function may be provided. Such an embodiment is shown schematically in FIG. In this case, the subtraction function replacing the subtractor 2 is performed by comparing digital signals.

The recording previous signal in the embodiment of FIG. 1 (FIG. 2 a) and the recording time of the signal (FIG. 3 a) is described as an equivalent in the position x _1. This is because the same information track 103 is scanned twice, but the present invention is not limited to this mode. That is, the signal a shown in FIG. 2 is recorded on a track different from the information track to be actually recorded.
May be obtained in advance. The signal b and the signal a and the position x ₁ at the time of recording when this, it is possible that already occurred a difference. This occurs when the relative position between the objective lens and the optical head is different even if the AT control is normal. In this case, in the position x _1, so that the signal c becomes zero, the signal b only Vdelta varied during recording it is sufficient to give the offset of Vdelta always the signal b.

Further, in the above embodiment, the moving direction of the light beam spot is described as the same direction when the relative position is stored and when the relative position is compared next, but may be reversed. At this time, when the data is input to the memory or the data is output from the memory, the time may be reversed. In addition, the moving speed of the light beam is described as being the same speed when comparing with the time of storing. However, it is needless to say that the moving speed of the light beam may be different when comparing with the time of storing. Of course, it can be processed by software.

(Effects of the Invention) The present invention has been described in detail above, and the following effects can be obtained.

(1) In the present invention, the relative position between the light condensing unit and the optical head is detected, and the detection of tracking or focusing control is detected based on the detection result.

Incidentally, in the conventional deviation detection, the level of a servo error signal (tracking or focusing error signal) is monitored, and when the level of the servo error signal exceeds a predetermined level, the deviation of the servo control is determined.
However, the servo error signal causes a large level change even with minute dust or scratches on the medium that does not cause servo departure, so that erroneous detection increases.

On the other hand, in the present invention, the signal indicating the amount of displacement of the light condensing means with respect to the optical head used for detection of deviation is not affected by the above-described dust and scratches (in the case of minute dust and scratches, the servo Even if the error signal changes, the change is at a very high frequency and the servo system itself does not react, as a result, the light condensing means is not displaced by the influence of dust and scratches.) Erroneous detection can be prevented.

(2) The value of the relative position between the light-collecting means and the optical head is stored for one track, and the stored value is compared with the detected value of the relative position to detect the deviation of the servo control. Therefore, it is possible to perform accurate detection of servo control deviating without being affected by a skew component (a tilt of a card, which corresponds to an eccentricity of a disk).

(3) When the relative position is stored and when the scanning direction of the light beam spot is in the opposite direction, the value obtained by reversing the order of the relative position values stored in the storage means is compared with the detected relative position. Make a comparison. Thus, in a mode in which information is recorded and reproduced while reciprocating like a card-shaped information recording medium, it is not necessary to store values of relative positions in two directions of forward movement and backward movement, and the capacity of the storage means is reduced. Can be reduced, and as a result, the cost of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a fourth embodiment of the present invention, FIGS. 2 and 3 are graphs for explaining signal levels in a track direction, FIG. 4 is a block diagram showing another embodiment of the present invention, FIG. 5 is a plan view schematically showing an optical card, and FIG. 6 is a schematic configuration diagram of the entire optical information recording / reproducing apparatus. 1 ... position sensor, 2 ... subtractor, 3 ... window comparator, 4 ... AD converter, 5 ... DA converter, 101 ... optical card, 102 ... information recording area, 10
3 ... Information track, 104, 104 '... Track selection area, 105 ... Home position, 106 ... Motor, 107 ...
... light source, 108 ... collimator lens, 109 ... beam splitter, 110 ... objective lens, 111 ... tracking coil, 112 ... focusing coil, 113,114 ... condenser lens, 115,116 ... photoelectric conversion element, 117 …… Tracking control circuit, 118 …… Focusing control circuit, 119…
... System controller, 121 ... Optical head, 122 ... Drive motor.

Claims (1)

(57) [Claims] 1. A method for recording and / or recording information by reciprocatingly scanning a light beam spot formed by a light condensing means of an optical head along a plurality of information tracks formed in parallel on a card-shaped recording medium. Alternatively, in an optical information recording / reproducing apparatus for performing reproduction, a means for detecting a relative position between the condensing means and the optical head with respect to a direction of the parallel arrangement of the information tracks, and a value of the detected relative position being 1 Means for storing the number of tracks, means for comparing the value of the stored relative position with the detected relative position, and comparing the value of the stored relative position with the detected relative position as a result of the comparison. Means for detecting that the tracking or focusing control has been deviated when the difference is equal to or more than a predetermined amount, wherein the optical vibrating is performed when the value of the relative position is stored and when the comparison is performed. When the scanning direction of the spot is reverse, the comparing means compares the value obtained by reversing the order of the relative position values stored in the storage means with the detected relative position. Characteristic optical information recording / reproducing device.