JPH04141836A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the writing of erroneous information by clocking time from when an instruction from an external controller is terminated and putting out the light of a light source emitting an optical beam when the clock time exceeds a set point. CONSTITUTION:When an optical card 1 is inserted into a device, MPU 52 zero- clears and starts an internal timer when it switches on a semiconductor laser. It judges whether an instruction is received from a host computer 50 or not. When there is no instruction, the counted value T of the timer is compared with a value Tc which is previously recorded as the set point in the internal memory. When the counted value of the timer exceeds the set point, MPU 52 puts out the semiconductor laser 64 with S6 and stops the count operation of the timer. Thus, the writing of erroneous information owing to the irradiation of the optical beam for a long time can easily be prevented without the need of a complicated device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical information recording/reproducing apparatus that optically records information on an information recording medium or reproduces recorded information by irradiating the information recording medium with a light beam.

[Prior Art] Conventionally, there are various types of media on which information is recorded using semiconductor lasers, such as disks, cards, and tapes. Information recording and reproducing devices using these recording media are generally connected to a host computer, which is a higher-level control device, and record and reproduce information according to instructions from the host computer. To record information on a recording medium such as the one mentioned above, for example, the laser beam emitted from a semiconductor laser is narrowed down to a minute optical spot and irradiated onto the track of the medium, and the intensity of the laser beam is modulated according to the recording information. Make a record. Further, in order to reproduce information, a track on which information is recorded is scanned with a laser beam having a power weaker than the laser beam intensity at the time of recording, and the information is reproduced by the reflected light.

By the way, in conventional devices, when waiting for the next command after executing an information recording or reproducing command from a host computer, it is common to wait with the semiconductor laser turned on. In this case, the light spot of the semiconductor laser remains stationary at the point where the track of the recording medium is selected, in preparation for track access for the next recording or reproduction command. However, if the light spot remains stationary for a long time, even if the laser light intensity is the reproduction power, erroneous information may be written in the stationary portion of the medium due to energy accumulation. Therefore, when accessing a track, there is a problem that the wrong track is accessed due to the incorrect information and the device malfunctions. Further, turning on the semiconductor laser while waiting for an instruction from the host computer not only shortens its lifespan but is also wasteful in terms of power consumption.

In order to solve this problem, for example, as disclosed in Japanese Patent Laid-Open No. 158034/1983, a means for recording or reproducing information by irradiating a card-shaped optical information recording medium with a light beam, means for relatively scanning the medium and the light beam during the recording or reproducing operation, and keeping the beam in a stationary state during non-operation, and irradiating the light beam when the light beam remains stationary for a certain period of time; An optical information recording/reproducing apparatus has been proposed, which includes means for stopping the information.

[Problems to be Solved by the Invention] However, the above device requires a special speed detection circuit for detecting the stationary state of the light beam, which makes the device configuration complicated and increases the cost. There was a problem with getting high.

The present invention was made to solve these problems, and its purpose is to provide an optical information recording and reproducing device that can easily prevent writing of incorrect information without requiring any special equipment. It's about doing.

[Means for Solving the Problems] In order to achieve the above object, an optical information recording medium is connected to an external control device, and information is recorded on the medium by irradiating the medium with a light beam according to a command from the external control device. optically recorded,
Alternatively, in an optical information recording and reproducing apparatus that reproduces recorded information, means for measuring the time elapsed after the command from the external control device is finished, and comparing this measured time with a set value, and comparing the measured time with a set value, There is provided an optical information recording and reproducing apparatus characterized in that it is provided with means for turning off a light source that emits the light beam when the light beam exceeds the wavelength range.

[Examples] Examples of the present invention will be described in detail 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 this embodiment, an information recording/reproducing apparatus using an optical card as a recording medium will be explained as an example.

In FIG. 1, numeral 1 denotes an optical card having a card-like shape, and numeral 51 denotes an optical card recording/reproducing device for recording information on the optical card 1 or reproducing the recorded information. Also, 50
is a host computer which is a higher-level control device, and the operation of the optical card recording/reproducing device 51 is controlled by instructions from the host computer 50.

The optical card recording/reproducing device 51 has an M for controlling each part of the device.
It includes a PU 52, a modulation/demodulation circuit 53 that modulates recorded information or demodulates reproduced information, a semiconductor laser drive circuit 54 that drives a semiconductor laser, and an AT/AF control circuit 55 that performs auto-tracking (AT) and auto-focusing (AF) control. There is. The optical card recording/reproducing device 51 also includes an optical head 56 incorporating a semiconductor laser or the like, a pulse motor 57 for moving the optical head 56 in the cross-track direction to access the target track with the optical spot, and an optical card. A DC motor 58 for sending the optical card 1 and a low reencoder 59 attached to the DC motor 58 for detecting the amount of feed of the optical card 1 are provided. Furthermore,
A PLL 60 for rotating the DC motor 58 at a constant speed, an insertion sensor 61 for detecting that the optical card 1 has been inserted, and a discrimination sensor 62 for detecting that the optical card 1 has been inserted correctly are arranged in the device. has been done.

FIG. 2 is a plan view of the optical card 1. In the recording area 2 of the optical card 1, a plurality of linear tracking tracks 3 are formed parallel to each other at regular intervals. Further, between each tracking track 3, an information track 4 for recording information 5 is provided. Note that 6 and 7 in the figure are areas for searching for a desired track.

FIG. 3 shows the configuration of the optical head 56. 64 is a semiconductor laser whose laser beam is collimated by a collimator lens 65 and then passes through a beam splitter 66 and enters an objective lens 67 . The objective lens 67 focuses the laser beam into a minute spot and irradiates it onto the recording layer 9 of the optical card 1 . On the other hand, the light reflected from the optical card 1 is returned to the objective lens 6.
7, enters the beam splitter 66, and is reflected to the condenser lens 68. The light flux passing through the condensing lens 68 is detected by a photodetector 69, and the detection signal is A T
/AF is sent to the F control circuit 55, and the AT
and AF sub-control is performed. The optical card 1 has a structure in which a recording layer 9 is formed on a support substrate 10, and a transparent protective layer 8 is formed on the surface thereof.

Next, the information recording and information reproducing operations of this embodiment will be explained. First, when the optical card 1 is inserted into the card insertion slot, the insertion sensor 61 detects this, and the MPU 52 drives the DC motor 58 based on this detection signal. As a result, a transport mechanism (not shown) is activated and the optical card 1 is introduced into the apparatus. At the same time, the determination sensor 62 determines whether or not the optical card 1 has been inserted in a normal state, and if the optical card 1 has been inserted correctly, the optical card 1 is transported to a predetermined position within the apparatus by the transport mechanism. Note that if the optical card 1 is inserted incorrectly, the optical card 1 is ejected to the card insertion slot. Next, MPU5
2 is for pulling in AF and AT in a predetermined area of the optical card 1.
The pulse motor 57 is driven to move the optical head 56 in a direction across the track by a mechanism not shown. After that, the MPU 52 drives the semiconductor laser drive circuit 54,
The semiconductor laser 64 in the optical head 56 is turned on. As a result, as described above, the laser beam is narrowed down to a minute spot and irradiated onto the optical card 1, and the reflected light is detected by the photodetector 69 to perform AT and AF sub-control. In this case, when the AF subcontrol and AT subcontrol function normally, the preformat information recorded on the optical card 1 is reproduced to confirm that it is a regular optical card. Note that at this time, the light spot is stationary in area 6 or 7 for track selection.

When recording information on the optical card 1, the host computer 50 sends a command to the MPU 52 to move the optical head 56 to a desired track. As a result, the MPU 52 drives the pulse motor 57 to move the optical head 56 in the cross-track direction, and irradiates the designated track with a light spot. Next, the host computer 50 issues a recording command to M.
The signal is sent to the PU 52, and in response to this, the MPU 52 drives the DC motor 58 to move the optical card 1. That is, the optical card 1 is moved back and forth so as to move relative to the light spot, and the light spot is scanned on the track. and,
The host computer 50 transmits the recorded information to a modulation/demodulation circuit 53.
The semiconductor laser drive circuit 54 drives the semiconductor laser 64 according to the modulated signal to record information on the designated track.

On the other hand, when reproducing recorded information on the optical card 1, the host computer 50 sends a command to the MPU 52 to move the optical head 56 to a desired track. MPTJ52 is
The optical head 56 is moved in the same manner as above to move the optical spot to the designated track. Next, the host computer 50 sends a reproduction command to the MPU 52, and in response to this, the MPU 52 drives the DC motor 58 to move the optical card 1 back and forth. As a result, the light spot scans the designated track, and a reproduction signal is obtained from the detection signal of the photodetector 69 at this time. The optical power of the laser beam during reproduction is set to such a weak optical power that no information is recorded. The reproduced signal is demodulated by the modulation/demodulation circuit 53 and then transferred to the host computer 50 as reproduction information. When information recording and reproduction are completed, the MPU 52 stops the rotation of the DC motor 58 and stops the feeding operation of the optical card 1. At this time, the light spot stands still in the track selection area 6 or 7, and waits for the next recording or reproduction command in this state.

During such information recording and reproduction standby, even if the light beam has the reproduction power as described above, if the light beam is irradiated for a long time, erroneous information will be recorded. Therefore, in this embodiment, the MCP 52 executes the following control. FIG. 4 is a flowchart showing the control operation of the MPU 52.

In FIG. 4, Sl is the light emission of the semiconductor laser 64, and as mentioned above, when the optical card 1 is inserted into the device, the MP
It is lit according to instructions from U52.

When the MPU 52 turns on the semiconductor laser 64, it clears an internal timer (not shown) to zero in S2, and then activates the timer in S3. Then, in S4, the MPU 52 determines whether or not an instruction has been received from the host computer 50, and if there is no instruction, the process proceeds to S5. In S5,
The MPU 52 compares the count value T of the timer with a value Tc recorded in advance as a set value in an internal memory. The value of Tc is set to a time sufficiently shorter than the time during which erroneous information is recorded if the light spot remains stationary.

When the timer count value exceeds the set value in S5, the MPU
52 turns off the semiconductor laser 64 in S6 and stops the counting operation of the timer in S7. In addition, the timer is cleared to zero in S8, the process returns to S4, and the host computer 5
Wait for command from 0. In other words, the host computer 50
If no command is received for a certain period of time, the semiconductor laser 64 is turned off and stands by. On the other hand, when a command from the host computer 50 is received in S5, lighting of the semiconductor laser 64 is checked in S9. If the semiconductor laser 64 is on, the SLL executes the command from the host computer 50, and if it is off, the SIO turns on the semiconductor laser 64, and then the Sll
Execute the command with . When all commands are completed, the process returns to S2 and the above-described operations are repeated.

In the above embodiments, a timer is used to measure time, but if the MPU does not have a timer function, a software timer program may be incorporated into the MPU 52, or a timer circuit may be provided externally. In addition, although an optical card recording/reproducing device was used as an example in the embodiment, the present invention is not limited to this.
It is applicable to all information recording and reproducing devices that perform optical recording and reproducing.

[Effects of the Invention] As explained above, according to the present invention, the light source that emits the light beam is turned off when no command is received from the external control device for a certain period of time. You can write information without the need for any complicated equipment.
There are effects that can be easily prevented. In addition, it has the advantage of not only extending the life of the light source (but also reducing power consumption).

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a plan view of an optical card, FIG. 3 is a configuration diagram of an optical head, and FIG. 4 is a flowchart showing the operation of essential parts of the present invention. . 1... Optical card 50... Host computer 51... Optical card recording/reproducing device 52... MPU 54... Semiconductor laser drive circuit 56... Optical head 64... Semiconductor laser 69... photodetector

Claims (1)

[Claims] An optical information recording medium connected to an external control device and irradiated with a light beam on the optical information recording medium according to a command from the external control device to optically record information on the medium or reproduce recorded information. In an optical information recording and reproducing device, the device includes a means for measuring the time elapsed after the command from the external control device is finished, and the measured time is compared with a set value, and when the measured time exceeds the set value, An optical information recording/reproducing apparatus comprising: means for turning off a light source that emits the light beam.