JPS61242338A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent a wrong recording action and to perform an access when an operation is restarted by providing a means to lower the intensity of a light beam in an inactive mode of recording or reproduction. CONSTITUTION:In a recording or reproduction mode both a motor 21 and a stepping motor 28 are driven by the control of a CPU 27. Then a light beam scans a data recording area 3. Here a light beam 32 given from a semiconductor laser 11 always has the power PWL or PR on an optical card 1 and is modulated with the power PWH according to the recording signal supplied from a terminal C1. While the reproduction signal is delivered from a terminal C2 in a reproduction mode. Thus the intensity of the beam is lowered in an inactive state where the beam is set under a static state. This prevents a wrong recording action. Furthermore, the access time can be reduced when an operation is restarted since the tracking control is carried continuously despite reduction of the beam intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical information recording/reproducing device, and particularly to a device used for a card-shaped optical information recording medium. The present invention
Here, the optical information recording and reproducing device refers to a device for recording information on a medium, a device for reproducing information recorded on a medium, and a device for both recording and reproducing as described above.

[Prior art]

2. Description of the Related Art Conventionally, various types of media such as disks, cards, tapes, etc. are known as media for recording information using light and for continuously outputting the recorded information. Among these, optical recording media formed in the form of cards (hereinafter referred to as optical cards) are compact, lightweight, and convenient to carry. It is expected to be in great demand as a medium for answering children.

In the original card mentioned above, information is recorded as an optically detectable recording pit string by scanning a preset recording track on the card with a light beam that is modulated according to the recorded information and focused on a minute spot. Ru. At this time, in order to accurately record information without causing problems such as crossing of recording bit strings, it is necessary to control the irradiation position of the original beam in a direction perpendicular to the scanning direction (auto tracking, hereinafter referred to as AT). It was necessary to do so. Further, in order to accurately focus the original beam onto the card, focus l1iII control (autofocusing, hereinafter referred to as AF) was performed. Therefore, in order to obtain a tracking signal and a focusing signal from the recording track, the modulated light beam is
It was set to have a predetermined power that would prevent writing on the card even at the minimum level. In addition, when reproducing recorded information, the above-mentioned recorded pit array is scanned with a light beam having a constant power at a level that does not allow information to be written on the optical card.

On the other hand, the information reproducing means of the optical card as described above scans the optical beam by relatively moving the original card and the original beam during recording or reproducing operations. Furthermore, since the recording tracks on the optical card are provided in a plurality of straight lines, the above-mentioned scanning is performed intermittently, and the optical beam is kept stationary during non-operation.

However, in such conventional devices, if the light beam remains stationary for a long time, the WAM code may be written due to energy accumulation even with the light beam at a level that does not allow writing as described above. there were. Such erroneous signals are still detected by the optical beam, and pose a major problem when accessing a track.

[Summary of the invention]

It is an object of the present invention to provide an optical information recording/reproducing apparatus which solves the drawbacks of the conventional apparatus, prevents false signals from being generated when the light beam is stationary, and is capable of always performing accurate recording or reproducing operations. There is a particular thing.

The above-mentioned object of the present invention is to provide an optical information recording/reproducing apparatus, a means for recording or reproducing information by irradiating a light beam onto a card-shaped optical information recording medium, and a means for recording or reproducing information between the medium and the light beam during the recording or reproducing operation. This is accomplished by comprising means for scanning the light beam relative to the medium and keeping the beam in a stationary state when not in operation, and means for lowering the intensity of the light beam on the medium when not in operation compared to when it is in operation. .

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic plan view showing an example of an optical card used in the apparatus of the present invention. In the figure, 1 is an optical card, 2 is a plurality of recording tracks formed in a straight line on the original card, 5 is a data recording area of the recording track where a light beam is scanned at a predetermined speed, and 41.42 is a desired track. 5 is the track selection area where the search is performed, and 5 is the home position of the original beam. The light beam is initially stationary at home position 5. During recording or playback, the light beam first moves to the track selection area 4. is moved in the a direction to find the Nth track 2 on which recording or reproduction is to be performed. The light beam then travels through the data recording area 3 on the track 2 in the direction of arrow C to perform recording or reproduction. When recording or playback is finished, the light beam stops within the track selection area 42;
It remains stationary until the next recording or playback. When a recording or playback command is received, this light beam
Move in the direction of arrow a within the selection area 4□ to the next track to be recorded or played back (for example, the N+1st track),
The data recording area 3 of this track is scanned in the direction indicated by the arrow, and recording or reproduction is performed in the same manner.

When this operation is repeated, a predetermined amount of data is recorded or reproduced.

Figure 3 is a diagram explaining the power of a light beam on an optical card during recording and reproduction. position, the vertical axis shows the optical power P. During recording, the light beam is emitted in the scanning range E, which corresponds to the data recording area, as shown in Fig. The optical card is always irradiated with the minimum necessary power PWL.Then, depending on the recording signal, it is modulated between the power PWII and the power required for recording, and only the portion irradiated with the power FWII! is recorded. A pit is formed.Furthermore, during reproduction, a light beam is irradiated with a constant power PR at which no recorded pit is formed in the scanning range ER, and the aforementioned recorded pit is read.

Here, the recording sensitivity 8 of the normal optical card is determined by the irradiation power P and irradiation time T of the light beam.

Therefore, as shown in FIG. 4, the spot of the light beam is changed from 62 to 6. When scanning is performed at a relative speed V, if the spot diameter is Φ, no recording is made if V is 077 or more. However, when the light beam is #simulating in a stationary state as described above, if this state continues for a long time, erroneous recording will occur even if the original power is RWL or PR as described above.

In the present invention, the intensity of the light beam on the medium is reduced during such non-recording and reproducing operations.

FIG. 1 is a schematic diagram showing an embodiment of the scientific information recording and reproducing device based on the present invention. Here, 1 is an optical card as shown in FIG. 2, and is placed on a mounting table 17 fixed to a bell 20. Belt 24 is connected to pulley 19,1
81c, the light guard 1 is moved in the direction of arrow d by the motor 21, and accordingly, the light guard 1 is also moved in the direction of d. Therefore, on the surface of the optical card, the light beam 52 irradiated from the optical head 16 is scanned in the direction b or C in FIG. The original head 16 includes a semiconductor laser 11, a collimator lens 12, a beam sinter 13, an objective lens 1
4 and a photodetector 15. The light beam 32 is emitted from the semiconductor laser 11 and is directed onto the optical card 1 by the objective lens 14 as a minute spot. Also,
The light beam 32 reflected by the optical card passes through the objective lens 14 again, is separated from the incident light by a beam splitter 15, and is detected by a photodetector 15. This photodetector 15
The detected signal is sent to the signal demodulation circuit 22, the tracking control circuit 23, and the focus control circuit 24, and the focus control # circuit 24 and the tracking control circuit 23
The objective lens 14t is moved in the direction of the original axis and in the direction perpendicular to the optical axis to perform AP and T.

28 is a stepping motor that moves the optical head 16 in a direction perpendicular to the plane of the paper. Move the irradiation position of the original beam in the direction a in Figure 2. The motor 21 is controlled by a motor drive circuit 25 to move and stop the optical card. Further, the driving speed of the motor 21 is determined by a speed detection circuit 29.
The speed detection circuit 29 is connected to a laser drive circuit 31 that drives the semiconductor laser 11 via a time measurement circuit 50.

Furthermore, the signal demodulation circuit 22, the stepping motor 28, the motor drive circuit 25, and the laser drive circuit 31 are connected to the central 6-processing unit (C!PU) through an interface 26ft, respectively.
27K connected.

In this apparatus, when performing a recording or reproducing operation, the motor 21 and the stepping motor 28 are driven under the control of the CPU 27, and the original beam scans the data recording area 3 as explained in FIG. At this time, the light beam 52 from the semiconductor laser 11 always has the power of PWL or PR shown in FIG.
Modulation is performed between the PWE and the PWE. Furthermore, during reproduction, a reproduction signal is output from terminal C2.

Next, the operation of the apparatus shown in FIG. 1 during recording will be explained with reference to FIG. FIG. 5(A) is an enlarged view of the recording surface of the optical card 1 described above. Recording track 2 M of data recording area 5
Between v 2 h++ t..., tracking tracks 8 for detecting tracking signals and clock tracks 7 for obtaining clock signals are alternately formed. Also, track selection area 4. An auxiliary track 9 is formed in order to keep the light beam from deviating from the track during non-operation. (C) indicates the relationship between the relative velocity V of the light beam and the recording surface with respect to the relative position on the source card, and (C) indicates the relationship between the intensity P of the recording beam and the relative position fifK on the destination optical card.

In the apparatus shown in FIG. 1, the light beam 32Vi is actually divided into three beams by a diffraction grating (not shown), and the spot of each beam is SI & ? in FIG. 5 (6).
82 a v S5 a or S+ b+ S2b*s
sb or 5ICeS20ySl (!) is irradiated onto the original card 1.

In addition, in FIG. 5(A), the intensity of the light beam is expressed by the diameter of the sbot for convenience. When recording information, the light beam (
The recording surface is scanned at a constant speed Vw, and recording is performed using the recording beam (center spot). At this time,
A tracking signal and a clock signal are detected from the spots at both ends, respectively. The intensity of the recording beam on the original card is CO
) is modulated according to information between PvH and PWL. That is, spots 821LpS2tl are each PW
H.

'Set to the strength of WL. Further, the intensity of the spot for obtaining the clock signal and the tracking signal is set to be lower than that of the center spot so that it is sufficient to obtain the signal and no recording is performed.

When recording is finished, the beam spot moves to the track selection area 4. As shown in Fig. 5(B), the relative speed with the recording surface decreases, and finally the spot sIC*521)*S5
Stand still at the position of ゜. At this time, the speed detection port $29 in FIG. make it work Here, a predetermined time Tc (for example, 1 second) is set in the time measurement circuit 30, and the time 1'1 after the above-mentioned V<VL is set.
When 4t becomes equal to Tc, an intensity reduction signal is sent to the laser drive circuit 51, and the injection 1 of the semiconductor laser 11 is
1It flow is controlled to reduce the intensity of spot B2Q on the optical card to PB. Then, when a tracking signal is detected at this spot 82c, and when v>vI is established when the work is started, the speed detection circuit 29 detects the tracking signal.
The intensity of 82 degrees was increased to Yuan Tsyu and recorded. Here, the spot 8200 intensity P8 is set to the minimum intensity for tracking, and to an intensity that does not cause recording even if the recording surface is irradiated for a long time in a stationary state. If t (T
During the period O, the next operation is started, and when Vp is reached, the time measuring circuit 30 is reset.

If TB is the time during which recording is performed with a stationary light beam of the above-mentioned optical power PWL, then TQ is Tc (even if configured to be variable stepwise with a switch set to TB or continuously with a volume control, etc.) Good. In addition, in Figure 5 (C),
Although it is depicted so that the intensity P reaches 2 days at the same time that the intensity changes to v and vL, in reality, it becomes P after a certain period of time due to the operation of the timer side circuit 30 mentioned above.

In the above explanation, the case of recording information was shown, but the case of reproducing information recorded on an optical card can also be explained as shown in FIG.
), if the strength during operation is a constant value PR,
Exactly the same operation as during recording is performed.

In the above embodiment, an example of setting the intensity of the light beam is, for example, the beam spot diameter is 5 μm, the recording scanning relative velocity Vv = 50 mm1B, and the reproduction scanning relative velocity V
R = 5001jl/S, and the relationship between the intensity P of the original beam and the writing time T is, when P = 5 mW, Ts = 1011148P
= 1 mW, Ts=iSP = 0.2 m
In the case of W, the intensity of the spots 82a and '2b described above should be set to PWH"' s mW pPWL"in", respectively. Here, the intensity ratio of the center spot and the spots at both ends (using a diffraction grating) (if the ratio is constant) 5:
1, the intensity of spots 85&, 851) is 1 respectively.
mW and 0.2 mW. Here, 0.2mW is
The intensity should be sufficient to obtain a tracking signal. 1 m
Limit relative velocity of light beam of W VL=Q/T8=5μm/
Since Kti vw (alternatively t: I1.
VR) > ML, recording is not possible with a light beam of 1 mW or less. In addition, the above TQ is set to 1 second, and P
s 'fc O, set to 2mW (this slot) before recording is made on the auxiliary track 9 at spot S2c)
The intensity at E+2° is reduced to 0.2 mW and no accidental writing occurs. If Pawl mW is used, the same holds true during playback.

As described above, according to the present invention, the intensity of the original beam is reduced during non-operation when the original beam is in a stationary state, so that the access time in the event of erroneous recording can be shortened.

The present invention is not limited to the above-described embodiments, and can be modified in various ways. For example, in the embodiment, the scanning speed of the light beam is directly detected from the motor, but it may be configured to start time measurement in accordance with a signal from apσ that controls the operation of the optical card. Alternatively, fast wave detection may be performed using a signal read out from a photodetector. Furthermore, without using a time measurement circuit, the power may be reduced by the intensity of the light beam as soon as V<VL.

In addition, even if the light beam has the minimum intensity to obtain a tracking signal, if recording is to be done in a stationary state for a long period of time (for example, one hour), the intensity of the light beam should be temporarily lowered during non-operation. If the next access does not resume for another hour, the light beam irradiation may be stopped.

The present invention can be applied not only to the above-described recording and reproducing apparatus, but also to a recording-only device and a reproducing-only device ff1K.

〔Effect of the invention〕

As explained above, the optical information recording and reproducing apparatus of the present invention is provided with a means for reducing the intensity of the light beam when recording or reproducing is not in operation, thereby preventing erroneous recording and preventing operation. When resumed, it has the effect of allowing access to be performed quickly. Furthermore, since high-power light emission for a long period of time during non-operation is eliminated, the life of a light source such as a semiconductor laser can be extended, and power consumption can be reduced. Furthermore, the present invention has the effect of preventing erroneous recording even when scanning of the original beam is stopped due to a disaster or the like.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the optical information recording/reproducing device of the present invention, FIG. 2 is a schematic plan view showing an example of an original card used in the device tc of the invention, and FIG. 5(A), (E
) are diagrams explaining the optical power on the optical card during recording and playback, respectively, Figure 4 is a schematic diagram showing how the spot of the light beam is scanned on the original card, and Figure 5 is the same as that shown in Figure 1. GA) is a plan view of the recording surface of the original card, (E) is a diagram showing the relationship between the position and speed of the original beam, and (0) is a diagram illustrating the relationship between the position and intensity of the light beam. It is a figure showing a relationship. 1...Optical card 11...Semiconductor laser 21...°Motor 29...Speed detection circuit 30...Time measurement circuit 51...Laser drive circuit

Claims (1)

[Claims] (1) A means for recording or reproducing information by irradiating a light beam onto a card-shaped optical information recording medium; and scanning the medium and the light beam relative to each other during the recording or reproducing operation; means for keeping the beam stationary;
an optical information recording/reproducing apparatus comprising means for lowering the intensity of the light beam on the medium when not in operation than when in operation.