JPH0546617B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention records information on an optical information recording medium, reproduces the information recorded on the medium, and/or reproduces the information recorded on the medium. The present invention relates to an optical information recording/reproducing device capable of erasing information. Such an information recording/reproducing apparatus is suitably applied, for example, as an information recording/reproducing apparatus using a card-shaped information recording medium in which a plurality of linear information tracks are arranged in parallel.

[Prior Art] Conventionally, the media used to record information using light and read out the recorded information have been disc-shaped,
Various types such as card-shaped, tape-shaped, etc. are known. Among these, optical information recording media formed in the shape of a card (hereinafter referred to as "optical card") are:
It is expected to be in great demand as a medium with a large storage capacity that is small, lightweight, and convenient to carry.

FIG. 4 is a schematic plan view of such an optical card 101, in which 102 is an information recording area, 103 is an information track, 104 and 104' are track selection areas, and 105 is a home position of a light beam spot.

Information is recorded on the optical card as an optically detectable recording bit string (information track) by scanning with a light beam that is modulated according to the recorded information and focused on a minute spot. On this occasion,
In order to accurately record information without causing problems such as crossing of information tracks, it is necessary to control the irradiation position of the light beam spot in the direction perpendicular to the scanning direction within the surface of the optical card (hereinafter referred to as auto tracking). (referred to as "AT"). In addition, in order to irradiate the light beam as a stable minute spot despite the bending and mechanical errors of the optical card, it is necessary to control the light beam in a direction perpendicular to the optical card surface (auto focusing, hereinafter referred to as "AF"). There is. Also, the above AT and AF are required during playback.

FIG. 5 shows a configuration diagram of a device for recording and reproducing information on an optical card, in which 106 is a motor for driving the optical card 101 in the direction of the arrow in the figure, and 107 is a light source such as a semiconductor laser. , 108 is a collimator lens, 109 is a beam splitter,
110 is an objective lens, 111 is a tracking coil, 112 is a focusing coil, 113
114 is a condenser lens, 115 and 116 are photoelectric conversion elements, 117 is a tracking control circuit, 1
18 is a focusing control circuit. The objective lens 110 is moved by passing current through the tracking coil 111 and the focusing coil 112 in accordance with commands from the control circuits 117 and 118 based on the tracking signals and focusing signals detected by the photoelectric conversion elements 115 and 116. Perform AT and AF.

Next, a method of recording and reproducing information will be explained with reference to FIGS. 4 and 5. Initially, the light beam spot is 1
I am at home position of 05. Next, the light beam spot moves through the track selection area 104 in the direction of u in the figure, finds the track N to be recorded or played back, and operates AT and AF there.
Track N is scanned in the r direction and recorded or reproduced. Light beam spot is track selection area 10
4', a large current is momentarily passed through the tracking coil 111 shown in FIG. 5, thereby causing the optical beam spot to be directed to the track (N+1). Therefore, the direction is changed to the l direction and the track (N
+1) to record or playback. and,
Depending on the amount of information, the scanning of the information track 103 by the light beam spot and the kicking operation of the light beam spot in the track selection areas 104, 104' are repeated several times in the same manner.

In the information recording/reproducing apparatus as described above, when the optical card 101 is reciprocated by the motor 106, vibrations are generally generated in each of the AT direction and the AF direction. This is because in the AT direction, the position of the optical beam spot relative to the information track tends to deviate due to causes such as parallel deviation (skew) of the information track with respect to the outer shape of the optical card or play in the optical card feeding mechanism. This is because the following operation is performed. On the other hand, regarding the AF direction, the AF makes a follow-up movement even though the optical beam spot tends to be out of focus with respect to the recording surface of the optical card due to causes such as warping of the optical card or play in the optical card feeding mechanism. It is from.

It is known that the magnitude or amplitude of such vibrations depends on the frequency of the vibrations. An example of such frequency dependence is shown in FIG. Note that FIG. 6 relates to the AT direction. here,
Assume that the skew is ±100 μm. If vibration in the AT direction is generated based only on this skew, the frequency dependence of the amplitude of the vibration in the AT direction is a
It is flat at 100 μm at frequencies up to the frequency _R of the reciprocating motion during scanning of the optical beam spot, and decreases at -12 dB/oct above the frequency _R. Therefore, in order to suppress the amount of AT deviation within ±0.1 μm, the open loop gain G _T of the AT servo must be G _T = 20 log ( ₁₀₀ /0.1) = 60dB, and at frequencies above the scanning frequency -
It may be reduced by 12dB/oct.

[Problems to be Solved by the Invention] However, in reality, vibrations in the AT direction are not only caused by the skew as described above, but also occur at a certain resonance frequency _P ( _R There are also vibrations that occur at < _P ). This is due to mechanical vibration of the transport mechanism due to rapid deceleration during reversal of the reciprocating movement of the optical card and sudden acceleration in the opposite direction. The vibration in the AT direction when including the inherent vibration during this reversal is b in Figure 6.
It will look like this. Therefore, in the past, in order to suppress the amount of AT deviation within ±0.1 μm even under the vibration during this reversal,
The AT gain was increased overall, as shown in β in Figure 6.

As a result, sufficient AT can be performed during reversal, but since the AT gain is higher than necessary, especially in high frequency bands, at times other than reversal, it is difficult to detect minute defects or attached dust on the surface of the optical card. The AT servo system operated sensitively, which sometimes caused deterioration in the quality of recording and playback signals.

The above description has been made regarding the AT direction, but the same applies to the AF direction.

[Means for Solving the Problems] According to the present invention, in order to solve the problems of the prior art as described above, a light beam spot is tracked and/or focused on an information track of an optical information recording medium. An optical information recording and reproducing device capable of recording information on a recording medium, reproducing information recorded on the recording medium, and/or erasing information recorded on the recording medium by relatively reciprocating the recording medium. Provided is an optical information recording/reproducing device characterized in that it has a control means for performing auto-tracking and/or auto-focusing at a servo gain different from that at the time of reversal of reciprocating motion than at the time of reversal. be done.

[Example] Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an optical card recording/reproducing apparatus which is an optical information recording/reproducing apparatus according to the present invention. Incidentally, in this figure, members having the same functions as in FIG. 5 above are denoted by the same reference numerals, and explanations thereof will be omitted here.

In FIG. 1, 121 and 122 are a tracking control circuit and a focusing control circuit, respectively. In the tracking control circuit 121, 1
21-1 is an amplifier that amplifies the electrical tracking signal from the photoelectric conversion element 115 to an appropriate voltage. 121-2 is an analog switch to which a signal is input from the amplifier 121-1 via points C and D. Reference numeral 121-3 is a driver, which receives a signal from the analog switch 121-2 and causes a drive signal current to flow through the tracking coil 111. In addition, the focusing control circuit 12
2, 122-1 is an amplifier that amplifies the electrical focusing signal from the photoelectric conversion element 116 to an appropriate voltage. 122-2 is an analog switch, into which a signal is input from the amplifier 122-1 via points A and B. Reference numeral 122-3 is a driver, which receives a signal from the analog switch 122-2 and causes a drive signal current to flow through the focusing coil 112.

In FIG. 1, 123 is a system controller that controls the recording/reproducing device, and 124 is a signal output from the controller that controls the direction of movement of the optical card (ie, the direction of rotation of the motor 106). In addition, from the controller 123, 124
Other signals are also output, but are not shown here.
125 is a motor driver that receives the signal 124 and controls the direction of rotation of the motor 106. 126
is a one-shot multivibrator circuit,
The circuit receives signal 124 and outputs signal 127 when the state of the signal changes. FIG. 2 is a time chart showing the relationship between the signals 124 and 127. That is, when the signal 124 changes from L level to H level and from H level to L level, a pulse signal 127 of width t is output. In addition, l and r in FIGS. 1 and 2 are signals 12
4 shows the direction in which the optical card 101 is moved by the motor 106. As shown, the reversal of the direction of optical card movement occurs within a time period of pulse width t of signal 127, that is, motor controller 125 starts decelerating when signal 124 changes level, approximately half of time t. It stops at , starts accelerating in the opposite direction, and rotates at a steady speed in approximately half of the time t.

The signal 127 is the analog switch 121
-2, 122-2 and controls the state of the switch. That is, when the pulse signal 127 is input (inverted), the switch 121
-2, the point C side is closed and the point D side is open, and the switch 122-2 has the point A side closed and the point B side open. On the contrary, the pulse signal 127
When is not being input (non-inverted), the switch 121-2 has the C point side open and the D point side closed, and the switch 122-2 has the A point side open and the B point side closed. Therefore, during non-inversion, the output voltages from amplifiers 121-1 and 122-1 are divided and output to drivers 121-3 and 122-1, respectively.
122-3, and when inverted, the output voltages from the amplifiers 121-1 and 122-1 are not divided and are input to the drivers 121-3 and 122, respectively.
-3, and thus the AT gain and AF gain during inversion can be set higher than when not inverted.

FIG. 3 is a graph showing the amplitude of vibration in the AT direction and the frequency characteristics of the AT gain in this example.

In Figure 3, c shows the AT direction vibration only during non-reversal, and d shows the AT direction vibration including the reversal.
This shows directional vibration. Note that these are the same as a and b in FIG. 6 above, respectively. In the device of this embodiment, when inverting (i.e., amplifier 121-1
When the output from the driver 121-3 is input to the driver 121-3 through point C), the AT gain is set to an amplification degree as shown by δ in FIG. When non-inverting, the amplifier 121
The output from -1 passes through point D to driver 121-
3, the AT gain has a shape in which δ is lowered overall, as shown by γ in FIG. This γ can be made similar to α in FIG. 6 by appropriately setting the resistance value between points C and D in FIG. 1 and other settings.

As a result, during non-inversion, there is no deterioration in the quality of the recording/reproduction signal due to excessive sensitivity due to excessive gain, and when inversion, the quality of the recording/reproducing signal is not degraded even under the occurrence of large high-frequency vibrations.
AT and AF can be performed. It should be noted that during inversion, since information is not recorded or reproduced, there is no concern that signal quality will deteriorate.

Although the explanation has been given above regarding the AT direction, similar gain settings can be made regarding the AF direction as well.

In the above embodiment, as shown in FIG. 3, an example is shown in which the AT gain δ at the time of inversion is raised flatly as a whole with respect to the AT gain γ at the time of non-inversion, but it is not necessarily flat. It is not necessary that the frequency be raised to 1, but it may be anything that sufficiently covers vibrations in the vicinity of the resonance frequency _P.

In the above embodiment, an example is shown in which the electrical gain is changed to change the gain, but in the present invention, the gain change includes other optical gain changes, mechanical gain changes, or electrical gain changes. These may be used in combination. That is, the AT gain and AF gain are determined by the product of these electrical gain, optical gain, and mechanical gain. For example, in order to change the optical gain, the light intensity of the light source 107 may be changed, an ND filter may be placed in or out of the optical path, or an ND filter with variable transmittance may be used and the transmittance of the filter may be changed. Therefore, in order to change the mechanical gain, it is possible to change the number of turns of the tracking coil 111 or to change the number of turns of the tracking coil 111 and the objective lens 110.
It is conceivable to change the distance between the magnet and the integrated magnet.

[Effects of the Invention] According to the present invention as described above, the tracking servo gain and/or focus can be adjusted when the relative movement between the light beam spot and the information track of the optical information recording medium is reversed and when it is not reversed. By switching the sing servo gain, it is possible to set the minimum necessary gain according to each time, and due to excessive gain when non-inverting, recording and playback signals may be affected by defects or attached dust on the surface of the recording medium. There is no possibility that the quality of the image will deteriorate, and there will be no occurrence of AT or AF deviations during reversal, and it is possible to improve reliability and error rate.

[Brief explanation of drawings]

1 and 5 are configuration diagrams of an optical card recording/reproducing device. FIG. 2 is a time chart of the signals. Figures 3 and 6 show the amplitude of AT direction vibration and
It is a graph showing AT servo gain. FIG. 4 is a plan view of the optical card. 121...Tracking control circuit, 122...
Focusing control circuit, 123... System controller, 125... Motor driver, 126
...One-shot multivibrator circuit.

Claims (1)

[Claims] 1. Recording information on an optical information recording medium by reciprocating the light beam spot while tracking and/or focusing on the information track of the optical information recording medium, and reproducing the information recorded on the recording medium; and/or in an optical information recording/reproducing device capable of erasing information recorded on the recording medium, auto-tracking and/or is performed using a servo gain different from that at the time of reversal of the reciprocating motion than at the time of reversal.
Alternatively, an optical information recording/reproducing apparatus characterized by having a control means for performing autofocusing.