JP3061283B2 - Video Disc Manufacturing Method - Google Patents

Description

The present invention relates to a method for manufacturing or reproducing a video disc capable of long-time reproduction.

(B) Conventional technology As a disk method for recording a wide-band high-definition video signal as it is in a baseband, a high-definition video signal is divided into two channels, and two adjacent recording beams are divided into independent video information. The method of recording the data with modulation is awarded. As a result, the recording disk has double spiral recording tracks, and the recording band is halved.

When reproducing this recording disk, reproduction information reproduced by two adjacent reproduction beams is combined to form an original high-definition video signal.

(C) Problems to be Solved by the Invention In the conventional example described above, the rotation speed of the disk can be reduced to half when reproducing the disk, but the reproduction time is one time.
/ 2, making it difficult to reproduce for a long time.

Furthermore, since information is simultaneously recorded on adjacent recording tracks, there is a risk that reproduced information may be lost simultaneously due to dropout. To compensate for this dropout, different interleaving processing is required for each track, and the recording circuit is also required to reproduce data. The circuit is also complicated.

(D) Means for Solving the Problems Accordingly, the present invention is to separately record line-sequential color video signals on a disk at a line cycle on a first disk rotating in one direction and on a second disk rotating in the other direction. Is a first feature, and a second feature is that a disk formed by recording a line-sequential color video signal on the front and back sides is simultaneously reproduced on both sides to form an original line-sequential color video signal.

(E) Operation According to the present invention, the line-sequential color video signal is distributed in the line cycle, one of the information is on the first disk rotating in one direction, and the other is on the second disk rotating in the other direction. The information is recorded independently on each disk and fixed by bonding. In addition, upon reproduction, both surfaces are irradiated with a reproduction beam, and the reproduction information reproduced at the same time is synthesized and converted into an original line-sequential color video signal.

(F) Embodiment Hereinafter, the present invention will be described according to an embodiment in which the present invention is applied to a video disc for recording and reproducing a high-definition video signal.

[Configuration of Signal Recording Apparatus] In this embodiment, a recording apparatus as shown in FIG. 1 is used for recording a high-definition video signal.

In this embodiment, a high-definition VTR1 is used as a high-definition video signal source. This high-definition VTR 1 is an analog VTR that reproduces and derives a baseband high-definition video signal recorded on a video tape using the built-in crystal oscillation circuit 2 as a reference signal.
The high-definition video signal is composed of a 20-MHz luminance signal and a 10-MHz color signal. In addition, instead of this analog VTR,
When using a digital VTR, the luminance signal band is 30M
The Hz color signal band is 15 MHz, and a recording apparatus having a wider recording frequency band than in this embodiment is required to record all this information without omission.

From the high-quality VTR, in addition to a high-quality video signal, an address code signal having a frame period recorded in a control track is reproduced and derived.
Oscillation output (48.6MHz) is also derived. This oscillation frequency corresponds to 1440 times the horizontal frequency of the high definition video signal.

The signal obtained from the high-quality VTR 1 is input to the recording encoder 3. The recording encoder 3 inputs two color signals to a line-sequencing circuit 4, a luminance signal to a time-division multiplexing circuit 5, and an address code to an address code detection circuit 6, respectively.

The line-sequencing circuit 4 forms and derives a line-sequential color signal by alternately selecting a color signal in a line cycle in synchronization with an address code and a synchronization signal.

The line-sequential color signal is input to the time axis compression circuit 7 and time axis compressed three times in a horizontal retrace period of the luminance signal in which both ends of each line are partially removed. The line-sequential compressed color video signal is time-division multiplexed in the time-division compression multiplexing circuit 5 and converted into a single-system line-sequential high-definition color video signal having almost the same arrangement as the MUSE signal. Circuit 8
Is input to

The signal selection circuit 8 selects a line-sequential high-definition color video signal every other line according to the recording surface designation signal, and time-division multiplexes the address code to a specific line in a vertical blanking period. Note that this selection results in selecting only the compression-multiplexed signal line of the same color signal in accordance with the recording surface designation signal, and the same color information is recorded on the same surface.

The selected signal is time-expanded twice in the time / minute expansion circuit 9 and input to the frequency multiplexing circuit 10 as a signal of about 12 MHz band.

The frequency multiplexing circuit 10 frequency-multiplexes the pilot signal generated by the burst signal generation circuit 12 on the back porch of the horizontal synchronizing signal by six periods. Note that the burst signal generation circuit 12 divides the crystal oscillation output by 1/6 and
A pilot signal of MHz is generated.

The frequency multiplexed output is input to an FM modulation circuit 11 that sets the FM shift range to 15.43 to 17.17 MHz, and is FM-modulated. The FM modulation output is supplied to the optical video disc recorder 15 as a recording signal.

Further, the recording encoder 3 clearly identifies the reference signal generating circuit 13 for changing the frequency of the reference signal in accordance with the address code to keep the recording linear velocity constant, and the recording end of the recording track on the disk record. End signal generation circuits 14 for performing the operations.

The reference signal specifies the rotational angular velocity of the disk in accordance with the address code. As a result, when the front and back sides of the bonded disk are simultaneously reproduced, the linear velocity of the recording track having the same address is always constant. Will match.

The end signal generation circuit 14 detects the end of recording from the address code, and outputs the end signal to the reference signal generation circuit 13.
Is input to the video disk recorder 15, and the reference signal generation circuit 13 fixes the reference signal frequency after the end signal is input.

Movement control means 16 in the video disk recorder 15
In the initial state, the optical recording means 17 is defined at the innermost circumference of the disk D. At the start of recording, the optical recording means 17 is moved in the outer circumferential direction along the guide rail at a speed inversely proportional to the PG pulse period. ing. Further, the movement control means 16
The position information in the radial direction is also detected by a built-in decoder, and the moving speed is corrected by comparing the detected position information with the address code.

Further, as a driving method of the movement control means 16, it goes without saying that a reference signal may be input and the optical recording means 17 may be moved at a speed proportional to the reference signal frequency or its divided output.

The recording means 17 optically modulates the recording signal during the recording period to form a recording track, and activates the mark signal generating circuit 19 at the timing of generating the recording end signal. This mark signal generation circuit 19 detects a period from the timing of the last PG pulse generation to the timing of the end signal generation, and
The PG pulse generation timing is delayed by the period, and a mark signal of a predetermined frequency is generated intermittently for a certain period. Therefore, the optical recording means 17 forms a visible end mark T outside the recording end E of the disk D (second.
(See FIG. 3).

The disk motor 20 rotates the disk D at a predetermined angular velocity in an initial state, and at the start of recording, is supplied with a supplied reference signal and derived from the disk motor 20.
The FG pulse and the FG pulse are input to the phase comparison circuit 21 for phase comparison. The phase comparison output is input to the motor drive circuit 22,
The rotation of the disk motor 20 is controlled in accordance with the reference signal frequency. The motor drive circuit 22 inverts the polarity of the drive voltage based on the recording surface designation signal, and inverts the rotation direction of the disk D according to the recording surface designation signal.

Therefore, when the first disk D1 is loaded and a surface designation signal is generated, the disk motor 20 is driven to rotate clockwise to form recording tracks from the inside to the outside in the counterclockwise direction, An end mark T is formed outside the recording end (see FIG. 2).

The signal to be recorded, the luminance signal of every other line and P _R
Signal.

Next, when a second disc is mounted and a backside designation signal is generated, the disc motor 20 is driven to rotate counterclockwise to form a recording track in a clockwise direction outward from the inside, An end mark T is formed outside the recording end (see FIG. 3).

Note that the signal to be recorded is a luminance signal every other line and P _B
Signal.

[Adhesion formation of double-sided disk] The disk recorded by the above-described procedure and the duplicated disk are bonded and fixed with the reproduction surface side outside.

In this first embodiment, it is assumed in the first embodiment that the front and rear end marks are aligned and fixed. In this way, when matching end marks,
Simultaneous reproduction by irradiating the same position on the front and back of the disc with a reproduction beam reduces the time lag of the reproduction information and the storage capacity of the delay means for timing adjustment can be reduced. Even the means can be omitted.

However, in the case where it is not possible to accurately adhere and fix even by the positioning, or when the recording timing includes a large fluctuation at the time of recording, the reproduction information in the front or the reproduction information in the back may precede. Therefore, during reproduction, delay means must be provided on both reproduction signal lines.

Thus, for example, if the front side end mark is adhesively fixed with the front end mark in a clockwise direction so that the front side reproduction information can always precede the rear side reproduction information, only the front side reproduction information can be obtained. The reproduction circuit can be simplified simply by controlling the delay.

In each of the embodiments, the end mark is used as an index for positioning, but the first embodiment requires the use of a measuring jig or the like to fix the end mark with high precision.

[Configuration of Reproducing Apparatus] Hereinafter, the configuration of the reproducing apparatus for simultaneously reproducing the double-sided disc according to the above-described embodiment from the front and back will be described with reference to FIG.

As is clear from the figure, in the video disk player, the double-sided disk is correctly mounted on both sides. The disk motor 23 is rotating at a predetermined speed in an initial state. Both the first pickup 24 on the front side and the second pickup 25 on the back side are defined by the first tracking control means 26 and the first tracking control means 27 at the innermost circumferences of the first disk D1 and the second disk D2, respectively. The reproduction beam irradiates the same position on both sides.

When the playback operation is performed, the playback output of both pickups is
The signals are input to the first FM demodulation circuit 28 and the second FM demodulation circuit 29, respectively, and are FM-demodulated.

The first demodulated output is input to a first low-pass filter 30, a first sync separation circuit 32, a first address detection circuit 34, and a first burst gate circuit 36, respectively. Similarly, the second demodulated output is supplied to the second low-pass filter 31 and the second sync separation circuit 3.
3, second address detection circuit 35, second burst gate circuit 3
Entered into 7 respectively.

Each address detection output is input to the first tracking control circuit 26 and the second tracking control circuit 27, respectively, and when the address detection timing has a difference, the reproduction track is changed.

The sync separation output is input as a burst gate pulse to the first burst gate circuit 36 and the second burst gate circuit 37, respectively, and separates the burst signal multiplexed at the synchronization front end.

Each burst signal is intermittently input to the first synchronous oscillating circuit 38 and the second synchronous oscillating circuit 39, and is converted into a continuous signal whose frequency is three times the burst signal. This continuous signal is used as a write clock.

Therefore, the AD conversion timings of the first AD conversion circuit 40 and the second AD conversion circuit 41 that input the respective low-pass outputs are performed in synchronization with each continuous signal.

Further, each continuous signal is inputted to a first write control circuit 42 and a second write control circuit 43, respectively, and a first delay means 44 and a second delay means 44 provided for jitter correction, timing adjustment and time axis extension are provided. It is converted into a write address signal of the means 45.

The first delay circuit 44 includes a first color memory 44
a and a first luminance memory 44b are provided to store color information and luminance information in separate memories. The second delay circuit 45 also includes a second color memory 45a and a second luminance memory 45b, and stores color information and luminance information in separate memories.

On the other hand, at the time of reading, the luminance information is alternately read from the two luminance memories at twice the speed at the time of storage, and the color information is obtained at a line cycle of 2/3 times the speed at the time of storage. It is necessary to read out each time. Therefore, in this embodiment, the output of the crystal oscillation circuit 46 oscillating at twice the frequency of the continuous signal is input to the readout control circuit 47 to read out the luminance signal information and the two-system color signal information, thereby realizing synchronization. doing.

Each information read, the first 1DA converter 48 for luminance and P _R
Is input to the 2DA converter 49 and the 3DA conversion circuit 50 for P _B of use.

Each DA conversion output is derived are respectively removing the third low-pass filter 51 and a fourth low-pass filter 52 and the P fifth respectively inputted to the low pass filter 53 DA conversion noise for _B for P _R for luminance .

In order to control the rotational speed of the disk, the divided output of the continuous signal generated by the second synchronous oscillator 39 is used as a comparison signal, and the divided output of the crystal oscillation output is used as a reference signal in the phase comparator 54. A comparison is made. The phase comparison output is supplied as a control input of the motor drive circuit 55,
The rotation control of the disk motor 23 is executed.

(G) Effects of the Invention According to the present invention, double high-definition video signals can be reproduced without inverting the disk, and special interleaving processing for dropout compensation is not required. Is big.

[Brief description of the drawings]

FIG. 1 is a recording-side circuit block diagram according to an embodiment of the present invention,
FIG. 2 is a schematic illustration of the front disk, FIG. 3 is a schematic illustration of the back disk, FIG.
Shown respectively. D1 first disk, D2 second disk 44 first storage means 45 second storage means

Continuing on the front page (72) Inventor Shigekazu Minechika 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Hiroshi Watanabe 2-18-18 Keihanhondori, Moriguchi-shi, Osaka (56) References JP-A-64-89077 (JP, A) JP-A-61-57068 (JP, A)

Claims (1)

(57) [Claims] 1. A method of selecting one video information and another video information by alternately allocating a line-sequential color video signal at a line cycle, and recording the one video information on a first disk rotating in one direction. Independently of the first disk, the other video information is recorded on a second disk rotating in the other direction, and the first and second disks or their duplicate disks are bonded and fixed with their reproduction surfaces outside. A method for manufacturing a video disk.