JPH0419612B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an optical recording/reproducing method for recording or reproducing information such as a video signal on a disk-shaped recording medium in the form of optical characteristic changes on the medium. The present invention relates to a device, and more specifically, to an overlapping recording prevention method that prevents information from being recorded on a medium on which information has already been recorded when the device performs a recording operation on a medium. It is something.

[Background of the invention]

In such optical recording and reproducing devices, a disk-shaped recording medium is generally used.
The information signal was recorded as a spiral or concentric recording trajectory on a disk-shaped recording medium. It will be played again from there.

Concentric recording trajectories are suitable for recording information divided into fixed intervals, such as still image information.
Conversely, a spiral recording trajectory (hereinafter referred to as a track) is suitable for recording and reproducing continuous signals such as video signals such as moving images and audio signals. When recording on spiral tracks, it is possible to perform high-density recording with a fixed track pitch, but it is also possible to record information on some tracks, stop recording, and then start again. When recording information,
Alternatively, when new recording is to be performed on a recording medium that has already recorded on some tracks, it is necessary to take care to prevent new recorded information from being overwritten on the already recorded portion.

As a measure to prevent such overwriting, for example, as shown in Japanese Unexamined Patent Publication No. 147141/1982, an optical recording/reproducing device is placed in the playback mode, and playback starts from the track to be recorded.
A method is known in which an attempt is made to detect an RF signal, and after confirming that no reproduced RF signal is detected, recording is performed on the track.

The conventional method as shown in this publication allocates information signals separated by fixed intervals, such as still images, to a spiral track provided on a disk, with one track for each piece of still image information. This is effective when recording, but if you want to record continuous signals such as moving images over several tracks in one recording by taking advantage of the characteristics of the spiral track, you can use the reproduced RF signal over several tracks. There is a problem that this method cannot be applied because it does not check in advance whether or not it has been detected.

It is also possible to further improve the above method and check the several tracks to be recorded using an optical recording/playback device that is set to playback mode, and then record the data.However, if the number of recording tracks is long, There is a problem in that the time required for the process is unnecessarily long, making it impractical.

[Purpose of the invention]

The present invention has been made in order to solve the problems related to the prior art as described above, and therefore, an object of the present invention is to To provide a method for preventing overwriting in an optical recording/reproducing device, which can prevent overwriting without unnecessarily spending a long time on unrecorded checks.

[Summary of the invention]

Therefore, in the present invention, before starting recording of a video signal in a specified track area spanning several tracks, a light spot is set in the specified track area from the middle of the track where the spot is located. sequentially to adjacent tracks,
By skipping, the presence or absence of the playback king RF signal is detected while moving at high speed, and after checking in advance whether a video signal has already been recorded in the specified track area, recording of the video signal is started. I did it like that.

[Embodiments of the invention]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is an explanatory diagram showing an example of a disk used in the present invention. As seen in the same figure,
In addition to the groove-shaped guide tracks 2, the disk 1 is formed with an address area 4 for storing address signals unique to each guide track and marks 3 used for recording position alignment for each guide track. .

In the figure, spiral track 2 is shown to simplify the explanation.
Although only a track is shown, it goes without saying that the track may be concentric.

FIG. 3 is an explanatory diagram showing the structure of the optical head 26 for recording and reproducing used in the present invention. In the figure, a light beam from a laser diode 5 is collimated by a collimating lens 6, and is collimated onto a disk 1 as a light spot by an objective lens 10 attached to an actuator 9 through a polarizing beam splitter 7 and a quarter-wave plate 8. Narrowed down.

The reflected light from the disk 1 is converted into parallel light again by the objective lens 10, passes through the 1/4 wavelength plate 8, is reflected by the polarization reflection surface of the polarization beam splitter 7, and is reflected by the mirror 12 after passing through the convex lens 11. The light beam is divided into two parts, one of which passes through a concave lens 13 and enters a two-part light-receiving element 14 for detecting a focusing error, and the other enters a two-part light-receiving element 15 for detecting a tracking error.

FIG. 4 is a block diagram showing an example of an optical recording/reproducing apparatus to which the present invention is implemented.

In the figure, 1 is a disk, 16 is a photo sensor for detecting recording positioning marks, 17 is a waveform shaping path, 18 is a disk motor, and 19 is a disk motor so that one rotation of the disk 1 corresponds to one frame of the video signal. 20 is a video signal generation source such as a TV camera, 21 is a recording signal processing circuit, 22 is a laser drive circuit, 23 is a keyboard for inputting the number of recording tracks, etc., and 24 is a microcontroller. 25 is a recording control circuit, 26 is the optical head shown in FIG. 2, 27 is a carriage on which the optical head 26 is mounted, and 28 is for moving the carriage 27 in the radial direction of the disk 1. , 29 is a carriage motor drive circuit, 30 is an IV conversion processing circuit, 31 is a reproduction signal processing circuit, 32 is a TV receiver, 33 is a focus control circuit, 34 is a tracking control circuit,
35 is an address demodulation circuit, and 36 is an RF detection circuit for detecting the presence or absence of a reproduction king RF signal.

The video signal from the video signal generation source 20 is subjected to FM modulation in the recording signal processing circuit 21 and is input to the laser drive circuit 22 as an RF signal. The laser drive circuit 22 outputs a high signal if the recording/reproduction switching signal j from the recording control circuit 25 is high (or a high signal if it is low).
During the Low) level, the output light of the laser mounted on the optical head 26 is intensity-modulated according to the input RF signal and irradiated onto the disk 1, and information is recorded as a change in the reflectance of the laser beam from the disk 1. Do this.

Also, during playback, if the record/playback switching signal j from the recording control circuit 25 is Low, it will be Low (or High).
(High) level, and the laser drive circuit 22
A low-power light beam of constant intensity is transmitted to disk 1.
The recorded information is detected via the I-V conversion processing circuit 30, and the reproduced signal processing circuit 3
1, and the reproduced image is displayed on the TV receiver 32.

The IV conversion processing circuit 30 converts the current detected by a light receiving element (not shown) provided in the optical head 26 for receiving reflected light into a voltage, and converts the detected signal into a voltage. The middle high frequency component b is the reproduced signal processing circuit 31 and the RF signal detection circuit 3.
6, the middle frequency component a is supplied to the address demodulation circuit 35, and the low frequency components are supplied as c to f to the focus control circuit 33 and the tracking control circuit 34.

FIG. 5 is a circuit diagram showing a specific example of the IV conversion processing circuit 30 for converting the signals detected by the two-split light receiving elements 14 and 15 in the optical head 26 from current to voltage.

The detection current from the two-split light receiving elements 14 and 15 for focusing error detection and tracking error detection is divided into a high frequency component and a low frequency component by a resistor R and a capacitor C, respectively, and the high frequency component is passed through the capacitor C. After being converted into voltage by amplifier 37
It becomes RF signal b, and also LPF (low pass filter)
38 to become the address signal demodulation signal a.
The low-frequency components are each converted into a voltage by a resistor R, and then passed through puffer amplifiers 39, 40, 41, and 42 to become signals c to f for focus control and tracking control.

Next, the case of recording a video signal will be explained.

In FIG. 4, after the recording start track and the number N of tracks to be recorded are input as the recording track area from the keyboard 23 to the system control 24, the system control 24 first selects the designated recording track area before starting recording. In order to check at high speed according to the present invention whether all of
input to the tracking control circuit 34 at a period of sec,
As a result, the optical head 26 is caused to jump from track to track, and as shown in FIG.
The output of the signal detection circuit 36 is checked.

FIG. 1A is a timing chart of each part signal at this time, and all the designated track areas are unrecorded, and each track jump pulse k and k
Reproducing RF signal detection circuit 3 in the track area between
This shows a case where no signal is output to the output No. 6.

In addition, in FIG. 1A, the tracking error signal fluctuates greatly every time the tracking jump pulse k is generated. This is a matter that inevitably occurs due to the jump of the optical head, and there is no need to explain it again. Probably.

As in this example, after checking that no signal is recorded in the specified track area,
Recording control circuit 2 configured as shown in FIG.
The number N of recording tracks is preset in the register 43 of No. 5 by the system control 24.

Next, the system control 24 confirms that the track currently being reproduced is the designated recording start track, and then outputs the REC trigger pulse h to the down counter 44 and gate circuit 46. The number N of recording tracks preset in the register 43 is read into the down counter 44 by the REC trigger pulse h.

On the other hand, in the gate circuit 46, after inputting the REC trigger pulse h, the recording/reproduction switching signal j is set to High (or Low) with the first recording position alignment mark pulse i.
level. The recording position alignment mark pulse i is input to the clock of the down counter 44, the disk rotates N times, and when N tracks have been recorded, the value of the down counter 44 becomes zero.

The coincidence detection circuit 45 detects that the value of the down counter 44 has become zero, and the gate circuit 46
Outputs a reset pulse to the recording/playback switching signal j
Switch to Low (or High) level and stop recording.

FIGS. 7 and 7A show an example in which a video signal is recorded in a designated track area.

A jump pulse k is input from the system control 24 to the tracking control circuit 34 at a period of 1 to 2 msec as described above, and the reproduced RF signal detection circuit 36 outputs the spot while moving the spot from track to track at high speed as shown in FIG. Check.

At this time, in the middle of the specified track area,
As shown at l in Figure A, if the signal M is detected at the output of the RF signal detection circuit 36 and it is found that a video signal has already been recorded on that track, the movement of the spot is stopped there. To inform a user that a video signal has already been recorded in a part of a designated track area.

Also, at this time, the optical recording/reproducing device can be shifted to the still image reproducing mode using the recorded track.

〔Effect of the invention〕

As explained above, according to the present invention, since a pre-designated track area is checked in advance before recording a video signal, there is no possibility of accidentally overwriting signals, and the pre-check is performed. Since the light spot is jumped from track to track at a high speed of 1 to 2 msec, the time required for the preliminary check is also shortened.

Additionally, if a track that has already been recorded is detected in the middle, the movement of the spot can be stopped at that part to notify the user that the spot is being recorded, and the track that has already been recorded can also be detected. It also has the effect of letting you know the phone number.

Note that if information is not recorded on even a part of one track, it means that information is not recorded on the entire track (as mentioned earlier, when recording information, one track is one frame). (because it is done in a corresponding manner)
It will be clear that the track-to-track jump pre-check of the present invention is effective.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the operation mode of an embodiment of the present invention, FIG. 1A is a timing chart of each part signal corresponding to FIG. 1, FIG. 2 is an explanatory diagram showing an example of a disk, and FIG. 4 is a block diagram showing an example of an optical recording/reproducing apparatus to which the present invention is applied, and FIG.
6 is a block diagram showing details of the recording control circuit 25 in FIG. 4, FIG. 7 is an explanatory diagram similar to FIG. 1, and FIG. FIG. 7A is a timing chart similar to FIG. 1A. Explanation of symbols, 1... Disk, 2... Guide track, 3... Recording positioning mark, 4... Address area of guide track, 5... Laser diode, 6... Collimating lens, 7... Polarizing beam splitter , 8... 1/4 wavelength plate, 9... Actuator, 10... Objective lens, 11... Convex lens, 12... Mirror, 13... Concave lens, 14,
15... Two-division light receiving element, 16... Photo sensor for detecting recording positioning mark, 17... Waveform shaping circuit, 18... Disc motor, 19... Disc motor drive circuit, 20... Video signal generation source, 2
DESCRIPTION OF SYMBOLS 1... Recording signal processing circuit, 22... Laser drive circuit, 23... Keyboard, 24... System control, 25... Recording control circuit, 26... Optical head, 27... Carriage, 28... Carriage motor, 29 ...carriage motor drive circuit, 3
0... I-V conversion processing circuit, 31... Reproduction signal processing circuit, 32... TV receiver, 33... Focus control circuit, 34... Tracking control circuit, 3
5... Address demodulation circuit, 36... RF detection circuit,
37...Amplifier, 38...LPF, 39-42...
...Patshua amplifier.

Claims (1)

[Claims] 1 Information is recorded by irradiating a track on a medium in the form of a laser beam, and information is recorded from a track on the medium by receiving reflected light from the irradiated light spot. In an optical recording and reproducing device that reproduces information, and if no information is recorded on even a part of one track, it may be determined that no information is recorded on the entire track. A means for detecting a reproduced signal obtained by reproduction, a jumping means for jumping a light spot from a certain track position to an adjacent track position, and specifying a track position at which recording should be started and the number of tracks to be recorded subsequently. For the track position specified by the specifying means and the subsequent track to be recorded, the jumping means moves the light spot from the middle of the track where the spot is located to the adjacent track. during which the recording information is not detected by the detection means, the designated track is determined to be an unrecorded track, and recording to the track is stopped. A method for preventing overlapping recording in an optical recording/reproducing device, characterized in that the overlapping recording is started. 2. In the overlapping recording prevention method according to claim 1, while the optical spot is sequentially skipped from the middle of the track where the spot is located to the adjacent track, the detection means An overlapping recording prevention method characterized in that when a reproduction signal of recorded information is detected, the recorded track shifts to a still image reproduction mode.