JPS6145416A - Overlapped recording preventing system in optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent an optical recording and reproducing device from the overlapped writing of signals in error by recording a video signal after previous checking of a specified track area. CONSTITUTION:Before the start of recording, a system control 24 inputs jump pulses (k) to a tracking control circuit 34 at a prescribed period to jump an optical head 26 from one track to another track, and during the jumping, checks the output of a reproducing RF signal detecting circuit 36. If no signal is outputted from the circuit 36 in a track area between respective pulses k and k, the system control 24 decides that the whole specified track area is unrecorded status. After checking that no signal is recorded in the specified track area, the control 24 presets the number of recording tracks in a register of a recording control circuit 25 to start recording.

Description

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

[Background of the invention]

In such optical recording/reproducing devices, a disk-shaped recording medium is generally used, and information signals are recorded on the disk-shaped recording medium as spiral or concentric recording loci, and are reproduced from there.

Concentric recording trajectories are suitable for recording information with divisions in fixed intervals for each still image information. The recording trajectory (hereinafter referred to as track) is suitable◇
When recording on spiral tracks, it is possible to perform high-density recording with a constant track pitch, but it is also possible to record information on some tracks, stop recording, and then start again. To prevent new recorded information from being overwritten on the existing green area when recording information on a recording medium that has already been recorded on some tracks, etc. It is necessary to give consideration to

As a measure to prevent such overlapping old recordings, for example, as shown in Japanese Patent Laid-Open No. 57-147141, an optical recording/playback device is placed in the playback mode, and playback starts from the target track to be recorded. Attempting to detect an RF signal,
A method is known in which recording is performed on the track after confirming that no reproduced RF signal is detected.0 The conventionally known method as shown in this publication is to record on a spiral track provided on a disk. This is effective when recording information signals divided into fixed sections, such as still images, by allocating one track for each still image information. When it is desired to record a continuous signal such as a moving image over several tracks, this method cannot be applied because it does not check in advance whether the reproduced RF signal is not detected over several tracks.

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 tracks, but if the number of recording tracks is long, the 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, the purpose of the present invention is to:
Overlapping recording in an optical recording/reproducing device that can prevent overlapping old recordings when recording continuous signals over several tracks on a disk without needing to spend a long time unnecessarily checking for unrecorded signals. The purpose is to provide a prevention method.

[Summary of the invention]

Therefore, in the present invention, before starting recording of a video signal in a specified track area extending over several tracks, a light spot is placed in the specified track area, and the light spot is placed in the middle of the track where the spot is located. ) to adjacent tracks in order to detect the presence or absence of a reproduced RF signal while moving at high speed, and check in advance whether a video signal has already been recorded in the specified track area. , 0 to start recording the video signal. [Embodiments of the Invention] Next, the present invention will be described in detail with reference to the drawings.

Figure i2 is an explanatory diagram showing an example of a disk used in the present invention. As seen in the figure, in addition to the groove-shaped guide track 2, the disk 1 includes an address area 4 in which an address signal specific to each guide track is stored, and an address area 4 for recording position alignment for each guide track. A mark 3 to be used is formed.

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

FIG. 3 is an explanatory diagram showing the structure of the recording/reproducing optical head 26 used in the present invention. In FIG. 2, the light beam from the laser diode 5 is passed through the collimating lens 6.
becomes parallel light, polarizing beam splitter 7, -wave plate 8
A light spot is focused onto the disk 1 by an objective lens 10 attached to an actuator 9 through the light beam.

The reflected light from the disk 1 is converted into parallel light again by the objective lens 10, and after passing through the wavelength plate 8, it is reflected by the polarization reflecting surface of the polarization beam splitter 7. After passing through the convex lens 11, the light beam is converted into parallel light by the mirror 12. The light is divided into two parts, one of which is transmitted through a concave lens 13 to a two-part light receiving element 14 for detecting a seven-occasion difference, and the other part is input to a two-part light receiving element 15 for detecting a tracking error.

FIG. 4 is a four-dimensional diagram showing a row of optical recording/reproducing apparatuses to which the present invention is applied.

In the figure, 1 is a disk, 16 is a recording positioning mark detection claw photosensor, 17 is a waveform shaping circuit, 18 is a disk motor, and 19 is a disk motor so that one revolution of the disk 1 corresponds to 17 frames 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.; 24 is a system control composed of a microcomputer, etc.; 25 is a recording control circuit; 26
2 is the optical head shown in FIG. 2, 27 is a carriage on which the optical head 26 is mounted, 28 is a carriage motor for moving the carriage 27 in the direction toward the disc 1, 29 is a carriage motor drive circuit, and 30 is an I-V 31 is a reproduction signal processing circuit, 32 is a TV receiver, 33 is a focus control surface/path, 34 is a tracking IW control circuit, 35 is an address demodulation circuit, and 36 is a circuit for detecting the presence or absence of a reproduction RF signal. This is an RF detection circuit.

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 F signal. If the recording/reproduction switching signal CD from the recording control circuit 25 is High, the laser drive circuit 22 is at High (or Low if it is Low) level.
The output light of a laser mounted on the optical head 26 is intensity-modulated according to an input RF signal and irradiated onto the disk IK, and information is recorded as a change in the reflectance of the laser beam from the disk 1.

Furthermore, during playback, if the recording/playback switching signal (j) from the recording control circuit 25 is Low (or F(i
If it is gh, it is set to High) level, and the laser drive circuit 22
irradiates the disc 1 with a low-output light beam of constant intensity, and converts the recorded information into the I-V conversion processing circuit 30.
, the reproduction signal processing circuit 31 performs FM demodulation, and the reproduction artist is displayed on the TV receiver 32 .

The IV conversion processing circuit 3o is for converting 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 focused on the reproduced signal processing circuit N31 and the F signal detection circuit 36, the middle frequency component (a) is focused on the address demodulation circuit 35, and the low frequency components are focused as (C) to (f). Control circuit 33 and tracking control surface M34
is supplied to

FIG. 5 is a circuit diagram showing a specific example of the knee-V conversion processing circuit 3o for converting the signals detected by the two-split light receiving elements 14 and 15 in the optical head 26 from current to voltage.

7 Orcus error detection and tracking error detection #I
The detection current from the two-split photodetector 14.15 is divided into a high-frequency component and a low-frequency component by a resistor and a capacitor C, and the high-frequency component is passed through the capacitor C to an amplifier 37.
After being converted to voltage by
It passes through an F (low bass filter) 38 and becomes an address signal demodulation signal (a). The low-frequency components are converted into voltages by resistors, respectively, and then sent to buffer amplifiers 39, 40, 41.4.
2, the signals (C) to (f) of the focus control layer and the tracking control layer are generated.

Next, the case of recording a video signal will be explained.◇In Fig. 4, from the keyboard 23 to the system control 24
After the recording start track and the number N of tracks to be recorded are input as the recording track area, the system control 24 first checks that all the specified recording track areas are in an unrecorded state before starting recording. In order to check this at high speed according to the present invention, here the jump pulse (k)eal~2m5 is input from the system control 24.
The signal is inputted to the tracking control circuit 34 at the ec period, thereby causing the optical head 26 to move from track to track, and as shown in Figure $1, the spot S is moved from track to track at high speed while jumping as shown in 81 to S6. During this time, the output of the reproduction ratio F signal output circuit 36 is checked.

The first person figure is a timing chart of each part signal at this time, and all the designated track areas are in state a, and each track jump pulse (10 and (k) is the track area between A case is shown in which no signal is output to the output of the detection circuit 36.

Note that in the 1st AW, the track jump pulse (k
The fact that the tracking error signal fluctuates greatly each time ) occurs is an inevitable occurrence as the optical head jumps, and there is no need to explain it again.

As in this example, after it is checked that no signal is recorded in the designated track area, the system controller 24 sends the signal to the register 43 of the recording control circuit 25 configured as shown in FIG. The number N of recording tracks is preset.

Next, the system control 24 confirms that the track currently being reproduced is the designated recording start track, and then outputs a trigger pulse (h) to the down counter 44 and gate circuit 46. down counter 4
In step 4, the number N of recording tracks preset in the register 43 is read by the trigger pulse (h).

On the other hand, in the gate circuit 46, REC) IJ Gabals (h)
After inputting , the recording/reproduction switching signal (j) is set to High (or Low
) level. The recording position alignment mark pulse (i) is inputted to the clock of the down counter 44, and when the disk rotates N times and 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, outputs a reset pulse to the gate circuit 46, switches the recording/reproduction switching signal U) to Low (or High) level, and starts recording. Stop.

FIGS. 7 and 7A show columns in which video signals are recorded in designated track areas.

A jump pulse (k) is inputted from the system control 24 to the tracking control circuit 34 at a cycle of 1 to 2 m5ec as described above, and the reproduced RF signal detection circuit 36 moves the spot from track to track at high speed as shown in FIG. Check the output of

At this time, in the middle of the specified track area, (
)), the signal M is output from the F signal detection circuit 36.
If it is detected that a video signal has already been recorded on that track, the spot movement is stopped and the spot is used to detect that a video signal has already been recorded on a part of the specified track area. Make sure to notify the person.

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 the pre-designated track area is checked in advance before recording the video signal, there is no accidental overwriting of signals, and the pre-check is easy. 1-2 spots
Since this is performed while jumping from track to track at the high speed of the rrlSCC cycle, the time required for the preliminary check is also shortened.

In addition, 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. It also has the effect of being able to notify the track number.0 Note that if information is not recorded on even a part of one track, it means that the entire track is not recorded with information (because as mentioned earlier, As such, the information record is 1
Since each track corresponds to one frame), it is clear that the preliminary check by jumping from track to track according to the present invention is effective.

[Brief explanation of the drawing]

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, @2 is an explanatory diagram showing an example of a disk, and FIG. An explanatory diagram showing the configuration of an optical head, Figure 4 is a block diagram showing an example of an optical recording/reproducing device to which the present invention is implemented, and Figure 5 is a specific example of the IV conversion processing circuit 30 in Figure 4. The circuit diagram shown in Figure 6 is the recording control circuit 2 in Figure 4.
FIG. 7 is an explanatory diagram similar to FIG. 1, and FIG. 7A is a timing chart similar to FIG. 1A. Code explanation 1...disc, 2...guide track, 3...recording positioning mark, 4...
・Address area of guide track, ...Laser diode, 6...Collimating lens, 7...
...Polarizing beam splitter, 8...1 wavelength plate, 9...actuator, 10°. ...Objective lens, 11... Convex lens, 12.
...Mirror, 13...Concave lens, 14,
15... Two-split 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, 21... 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, 30 ... I-V conversion processing circuit, 31 ... Reproduction signal processing circuit, 32 ...
・TV receiver, 33...Focus control circuit,
34... Tracking control circuit, 35...
...Address demodulation circuit, 36...F detection circuit, 37...Amplifier, 38...LPF,
39-42...Buffer amplifier agent Patent attorney Akio Namiki Figure 1 All! Figure 2 Figure 3

Claims (1)

[Claims] 1) Information is recorded by projecting a laser beam in the form of a light spot onto a track on the medium, and information is recorded from the track on the medium by receiving reflected light from the projected light spot. An optical recording and reproducing apparatus for reproducing recorded information includes a means for detecting a reproduced signal obtained by reproducing recorded information, a jumping means for jumping a light spot from a certain track position to an adjacent track position, and a means for detecting a reproduced signal obtained by reproducing recorded information; means for specifying a track position to start and the number of tracks to be recorded following the track position specified by the specifying means and a track to be recorded subsequent to the track position specified by the specifying means, the optical spot is set by the skipping means. is sequentially skipped from the middle of the track where the spot is located to the adjacent track, and during this time, when the detection means does not detect a reproduction signal of recorded information, the track designated by the designation means 1. A method for preventing overlapping recording in an optical recording/reproducing apparatus, characterized in that the track is determined to be an unrecorded track and recording to the track 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 A method for preventing overlapping recording, characterized in that when a reproduction signal of recorded information is detected, the mode shifts to a still image reproduction mode for the recorded track.