Optical disc recording/playing apparatus and method for synchronizing recording of new data

An optical disc recording/playing apparatus appropriate to accommodate a large scaled driver by spotting laser beams on a signal track of an optical disc, wherein a data is recorded in a certain density to have a certain distance between the laser beams so as to facilitate a data recording and reproducing. The optical disc includes a spiral track thereon having a land and groove structure, wherein the track is unwobbled and identical in width of lands and grooves thereof and further there are not recorded a free-formatted pilot signal for controlling a spinning rate of the disc and an address signal for detecting a track location.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an optical disc player, and more 
particularly to an optical disc recording/playing apparatus and method for 
improving data recording capacity and compatibility of an optical disc. 
2. Description of the Prior Art 
An optical disc recording/playing apparatus generally records data on an 
optical disc and retrieves the recorded data by scanning portions of the 
optical disc by a laser beam converged via an optical pick-up, wherein the 
optical pick-up focusing, tracking and the spinning rate of the optical 
disc are controlled. 
In a play-only optical disc such as a compact disc (CD), an information 
signal is continuously recorded in the form of pits formed along a spiral 
track of the disc. That is, the general optical disc recording/playing 
apparatus scans a focused laser beam to a signal pit of an optical disc 
and carries out tracking control for detecting a synchronous signal of a 
channel bit signal array, and compares the frequency and phase of the 
detected synchronous signal with those of a standard synchronous signal to 
thereby detect a control signal for controlling the spinning rate of the 
optical disc. 
As shown in FIG. 1, a conventional optical disc playing apparatus includes: 
a turntable 2 which accommodates an optical disc 1 placed thereon; an 
optical pick-up 3 for projecting a laser beam to the optical disc 1, 
detecting the laser beam reflected against the optical disc 1, and 
converting the detected value into electrical signals a, b, c, d, e and f; 
a laser stabilizer 4 for stably transmitting a laser beam to the optical 
pick-up 3; a playback signal processor 5 for receiving the electrical 
signals a, b, c, d, e and f output from the optical pick-up 3 and 
generating a focus control signal Fe, a tracking control signal Te and a 
radio frequency generating signal RF; a focusing controller 6 for 
performing a focus control of the optical pick-up 3 in accordance with the 
focus control signal Fe output from the playback signal processor 5; a 
tracking controller 7 for performing tracking control in accordance with 
the tracking control signal Te output from the playback signal processor 
5; a channel bit signal processor 8 for zero-crossing the radio frequency 
generating signal RF output from the playback signal processor 5 
to-thereby produce a square wave signal and detecting a channel bit row 
signal CHBr and a synchronized signal of a channel bit row SYNr; a digital 
signal processor 9 for decoding the detected channel bit row signal CHBr 
and performing error correction so as to convert such signal into digital 
data; a standard clock signal generator 10 for generating a standard 
synchronized signal SYNs; a motor control signal generator 11 for 
generating a motor control signal Me by comparing the standard 
synchronized signal SYNs output from the standard clock signal generator 
10 with the channel bit synchronized signal SYNr output from the channel 
bit signal processor 8; and a motor controller 12 for controlling a motor 
13 in accordance with the motor control signal Me output from the motor 
control signal generator 11. 
The optical pick-up 3 includes: a laser diode LD for generating a laser 
beam; a grating GR for branching the laser beam output from the laser 
diode LD into a main beam and a pair of subbeams for controlling a 
tracking servo; a beam splitter BS for splitting the beam from the laser 
diode LD and the beam reflected against the disc; an object lens OL for 
converging the three laser beams passing through the beam splitter BS onto 
a portion of a signal track of the disc; a focus activator FA and a 
tracking activator TA for moving the object lens OL in the direction of 
tracking and/or focusing so that the object lens OL can accurately 
converge the three laser beams onto a signal track of the disc; a wolla 
stone prism WP for reflecting a beam which has been reflected from the 
disc and has passed through the beam splitter BS; a sensor lens SL for 
converging a beam reflected from the wolla stone prism WP; and a photo 
detector PD for converting the laser beam converged by the sensor lens SL 
into electrical signals a,b,c,d,e and f. 
With reference to the accompanying drawings, the operation of the thusly 
composed conventional optical disc playing apparatus will now be 
described. 
First, when the laser diode LD of the optical pick-up 3 generates a laser 
beam under the control of the laser stabilizer 4, the grating GR branches 
the laser beam into a main beam and a pair of subbeams for the tracking 
servo. Then, the beam splitter BS projects the three beams toward the 
object lens OL. 
The object lens OL converges the three beams projected thereto through the 
beam splitter BS onto a signal track of the disc, and a beam reflected 
from the portion of the signal track of the disc is converged passing 
sequentially through the beam splitter BS and the wolla stone prism WP to 
the sensor lens SL. The beam passing through the sensor lens SL is 
converted by the photo detector PD into electrical signals a,b,c,d,e and 
f. 
At this time, the focus activator FA and the tracking activator TA move the 
object lens OL in the direction of tracking and/or focusing in order for 
the object lens OL to accurately converge the three beams. 
That is, as shown in FIG. 2A, when the object lens OL projects the three 
beams onto a signal track of the disc, the main laser beam LB is 
positioned directly on a pit row of the signal track as shown in FIG. 2B, 
and the other two subbeams LBr, LBl are respectively positioned on the 
left and right sides of the main beam LB. At this time, assuming that a 
track pitch Tp denotes an intertrack distance, the pair of subbeams LBr, 
LBl are positioned to be 0.25 Tp away from the track, respectively. 
As shown in FIG. 2C, the photo detector PD includes a main photo detecting 
element for detecting the amount of the reflected main laser beam LB and 
secondary photo detecting elements for detecting the reflected subbeams. 
At this time, the main photo detecting element is partitioned to form four 
photo detecting elements PDA-PDD, and the pair of secondary photo 
detecting elements PDE, PDF are respectively provided above and below the 
main photo detecting elements PDA-PDD. 
The main photo detecting elements PDA-PDD of the photo detector PD detect 
the amount of reflected main laser beam LB to generate electrical signals 
a,b,c,d and the secondary photo detecting elements PDE, PDF detect the 
amount of the reflected subbeams LBr, LBl to generate electrical signals 
e,f. 
The playback signal processor 5 receives the electrical signals a to f 
detected in the photo detector PD and obtains a radio frequency generating 
signal RF by summing the signals a through d (a+b+c+d). A focus control 
signal Fe is obtained using the equation (a+c)-(b+d), and by subtracting f 
from e (e-f), a tracking control signal Te is obtained. 
The focus controller 6 operates the focus activator FA of the optical 
pick-up 3 in accordance with the focus control signal Fe output from the 
playback signal processor 5, and the tracking controller 7 operates the 
tracking activator TA of the optical pick-up 3 in accordance with the 
tracking control signal Te of the playback signal processor 5. 
The channel bit signal processor 8 zero-crosses the radio frequency 
generating signal RF output from the playback signal processor 5 and 
converts the same into a round wave signal, to thereby detect the channel 
bit row signal CHBr and the channel bit synchronized signal SYNr. At this 
time, the channel bit row signal CHBr is decoded, error-corrected, 
converted into digital data in the digital signal processor 8 and 
processed according to various applications. 
The motor control signal generator 11 generates a motor control signal Me 
by comparing the standard synchronized signal SYNs output from the 
standard clock signal generator 10 with the channel bit synchronized 
signal SYNr output from the channel bit signal processor 8, and in 
accordance with the motor control signal Me the motor controller 12 
controls the motor 13 to thereby control the spinning speed of the optical 
disc 1. 
In blank optical discs used for recording signals thereon, information 
signals such as channel bit signals are not recorded as in compact discs, 
but auxiliary signals are recorded thereon which is free-formatted 
according to a certain standard so as to control the tracking and the 
spinning speed of the optical disc. At this time, the free formatted 
auxiliary signals include a record signal, an address information signal 
for denoting the location of a corresponding track and a pilot signal for 
controlling the spinning speed of the disc. In this case, a track having 
lands and grooves is formed to control tracking, and tracking control 
signals are obtained therefrom. 
The pilot signal having a certain cycle is recorded along the lands and 
grooves of the track, and the spinning speed of the disc is determined by 
detecting the cycle of a read pilot signal. In accordance with the 
determined spinning speed, data is recorded at a certain speed and 
density. In this case, random recording is possible because address 
information signals defining a serial location on the track are recorded. 
In an orange book of the compact disc there is a standard for recording and 
playing spare signals free-formatted by a wobbling method in which, as 
shown in FIG. 3, a periodic wobbling in a free-formatted standard is 
applied to the lands or grooves of the track for denoting a pilot signal 
to detect the spinning speed of the disc and records an address 
information signal by phase-modulating the wobbling signal. 
Then, data is recorded in the signal tracks having wobbled grooves and the 
main laser beam LB for reading the information is positioned on the signal 
track. The pair of subbeams LBr, LBl for detecting a tracking control 
signal are positioned on the left and right side from the main beam LB to 
thereby detect the beam reflected against the signal track. 
Meanwhile, the technological developments of the optical disc and its 
player have been made to improve data storage capacity by resolving 
intertrack interference. 
There are no problems when recording a wobbling signal on lands of a track 
by using a wobbling method, however, when recording information in the 
grooves of a track, problems due to undesired reading of different 
wobbling signals recorded on the lands next to a groove occur and a pilot 
signal for controlling the motor is not properly detected. Conversely, 
when recording a wobbling signal in a groove of the track, there also 
occurs a problem in recording information on a land of the track. 
Therefore, a constant angle velocity CAV control method or a zoned CAV 
control method are recommended, but due to a low recording capacity these 
methods are known to be inappropriate for recording/playing a large amount 
of data which must be serially reproduced as in the case of video image 
data or voice data. 
Further, when recording and using a free-formatted pilot signal on the 
disc, only a recording/playback apparatus having the proper pilot signal 
standard can be employed as an optical disc player and a recording 
capacity of a disc is restrictively confined by set standards. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an optical 
disc recording/playing apparatus and method thereof for recording and/or 
reproducing a data on/from the optical disc wherein the track of the disc 
is unwobbled and there is not recorded a free-formatted auxiliary signal 
such as a pilot signal and an address signal. 
To achieve the above described object, the optical disc recording/playing 
apparatus includes: a record laser beam for recording a signal on a signal 
track of the disc; playback laser beams spaced from the record applied 
laser beam by a certain distance for thereby reading a signal recorded on 
the disc; an optical pick-up for projecting the laser beams; a playback 
signal processor for receiving a playback signal output from the optical 
pick-up and generating a tracking control signal, a focusing control 
signal and a radio frequency signal; and a focusing and a tracking 
controller for performing a focusing and a tracking operation in 
accordance with a focusing and a tracking control signal output from the 
playback signal processor. 
Further, the optical laser disc recording/playing apparatus, wherein the 
optical disc includes a spiral track thereon having a land and groove 
structure and the track is unwobbled and there is not recorded a 
free-formatted pilot signal for controlling a spinning rate of the disc, 
includes: an optical pick-up for recording or playing-back a data on or 
from a signal track of the disc by using a first, a second and a third 
laser beam which are multipled by a grating; a playback signal processor 
for generating a focusing control signal, a tracking control signal and a 
first radio frequency signal in accordance with a signal reproduced in the 
optical pick-up through the first laser beam; a first signal shaper for 
removing a signal which is light-modulated by shaping a radio frequency 
signal reproduced by the second laser beam in the optical pick-up, and 
generating a second radio frequency signal; a second signal shaper for 
removing a signal which is light-modulated by shaping a radio frequency 
signal reproduced by the third laser beam in the optical pick-up, and 
generating a third radio frequency signal; a radio frequency signal 
detector for detecting a third radio frequency signal output from the 
second signal shaper; a microcomputer for receiving the output of the 
radio frequency signal detector and determining whether the received 
signal is an initial recording carried out on a blank track of the disc or 
a second recording carried out on a recorded track of the disc to thereby 
control the disc player system; a playback signal selector for generating 
one selected from the second and the third radio frequency signal output 
from the first and the second shaper, in accordance with a control signal 
of the microcomputer; a channel bit signal processor for processing the 
radio frequency signal selected from the playback signal selector and 
generating a playback channel bit signal, a playback channel bit 
synchronous signal and a playback channel bit clock signal; a digital 
signal processor for decoding and error-correcting the detected channel 
bit signal, and generating a playback data; a standard clock signal 
generator for generating a standard clock signal and a standard 
synchronous signal; a playback motor control signal detector for comparing 
the standard synchronous signal output from the standard clock signal 
generator with the playback channel bit synchronous signal output from the 
channel bit signal processor and detecting a playback motor control 
signal; a record motor control signal detector for receiving the second 
radio frequency signal from the first signal shaper, the playback channel 
bit signal and the playback channel bit clock signal from the channel bit 
signal processor, and detecting a record motor control signal; a motor 
control signal selector for receiving one selected from the playback motor 
control signal output from the playback motor control signal detector and 
the record motor control signal output from the record motor control 
signal detector, and generating a motor control signal, in accordance with 
the control of the microcomputer; a synchronous delay unit for delaying 
the playback channel bit synchronous signal output from the channel bit 
signal processor and generating a delay synchronous signal; a record clock 
selector for receiving one selected from the standard clock signal output 
from the standard clock generator and the playback channel bit clock 
signal output from the channel bit signal processor, and generating a 
record clock signal, in accordance with the control of the microcomputer; 
a record digital signal processor for coding and decoding a record data; a 
channel bit processing transfer unit for adding the delay synchronous 
signal and an address signal to the output of the record digital signal 
processor and generating a record channel bit signal according to the 
record clock signal, in accordance with the control of the microcomputer; 
a first light stabilizing modulator for controlling the amount of the 
first laser beam output from the optical pick-up so as to correspond to 
the record channel bit signal output from the channel bit processing 
transfer unit, in accordance with the control of the microcomputer; and a 
second light stabilizer for controlling the amount of the laser beam 
output from the optical pick-up and applying the light amount signal to 
the first and the second signal shaper, in accordance with the control of 
the microcomputer. 
Still further, the optical disc recording/playing method, wherein the 
optical disc includes a spiral track thereon having a land and groove 
structure and the track is unwobbled and there is not recorded a 
free-formatted pilot signal for controlling a spinning rate of the disc, 
comprising the steps of: judging whether to record a data on the disc or 
reproduce a data recorded on the disc; controlling, when reproducing a 
signal recorded on the disc, the light stabilizing modulator to thereby 
adjust the laser diode to have a light amount at a read mode, and turning 
off the laser diode by controlling the light stabilizing modulator; 
selecting the first radio frequency signal output from a photo detector by 
controlling a playback signal selector and the playback motor control 
signal output from the playback motor control signal detector by 
controlling a motor control signal selector, thereby controlling a motor; 
and decoding and error-correcting the playback channel bit signal output 
from the channel bit signal processor and generating a playback data to 
thereby read a data recorded on the disc. 
Furthermore, the optical disc recording/playing method, wherein the optical 
disc includes a spiral track thereon having a land and groove structure 
and the track is unwobbled and there is not recorded a free-formatted 
pilot signal for controlling a spinning rate of the disc, comprising the 
steps of: judging whether to record a data on the disc or reproduce a data 
recorded on the disc; adjusting, when recording a data, the laser diode to 
have a light amount at a read mode by controlling the light stabilizing 
modulator, detecting a radio frequency signal, and judging whether the 
recording is an initial recording on a blank disc or a second recording on 
a recorded disc; adjusting, when recording a data on a blank disc, the 
first laser diode to have a light amount at a write mode by controlling 
the light stabilizing modulator, and controlling the second laser diode to 
turn to a light amount at a read mode; selecting a second radio frequency 
signal from the playback signal selector, controlling the motor control 
signal selector to select a motor control signal in accordance with the 
record motor control signal, and selecting a standard clock signal in 
accordance with the record clock signal; processing a record data to an 
appropriate format by controlling the channel bit processing transfer unit 
120, applying a record channel bit signal to the light stabilizing 
modulator in accordance with the record clock signal, and controlling a 
light amount emitted from the first laser diode, thereby recording a 
signal; adjusting, when recording a data on a record disc, the first laser 
diode to have a light amount at a read mode by controlling the light 
stabilizing modulator, and controlling the second laser diode to turn to a 
light amount at a write mode; selecting a first radio frequency signal 
from the playback signal selector, controlling the motor control signal 
selector to select a motor control signal in accordance with the record 
motor control signal, and selecting a standard clock signal in accordance 
with the record clock signal; processing a record data to an appropriate 
format by controlling the channel bit processing transfer unit, applying a 
record channel bit signal to the light stabilizing modulator in accordance 
with the record clock signal, and controlling the first laser diode, 
thereby recording a signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in FIG. 4, along the surface of an optical disc applicable to the 
present invention there is formed a spiral track having an unwobbled land 
and groove structure, wherein there is not recorded a free-formatted pilot 
signal which is provided to control a spinning rate of the disc. 
A plurality of laser beam spots are-positioned along a track of the disc 
having a certain distance from each of the spots. That is, a laser beam 
spot LB1 for recording, and one laser beam LB2 or two laser beams LB2, LB3 
for playing-back are spotted on a track turing against the spinning 
direction of the disc. 
In a case that there are provided a pair of playback laser beams, the pair 
of beam spots LB2, LB3 are spotted on a rear and a front portion of the 
track, respectively, while spacing by a certain distance dL from the 
record laser beam spot LB1. Here, a previously recorded data is read 
according to the laser beam LB3 and a data recorded by the beam LB1 is 
read according to the laser beam LB2. 
In another case that there is provided one laser beam for playing-back, the 
playback laser beam LB2 is spotted behind the record laser beam spot LB1 
and spaced by a certain distance dL from the beam spot LB1 to thereby read 
data recorded on a signal track by the record laser beam LB1. 
That is, on a rear portion of the record beam spot LB1 the playback laser 
beam LB2 reads data recorded on the disc by the record beam LB1, and the 
playback laser beam LB3 reads a previously recorded data. Here, the record 
beam LB1 enables a new data to be recorded on a previously recorded old 
data. 
Recording a data on a blank optical disc will now be described. 
Data is recorded on the blank disc by the record laser beam LB1 in 
accordance with a focus control and a tracking control of an optical 
pick-up. Here, the tracking control according to a single beam push-pull 
method is available, because the focus control employs a flying spot 
astigmation method and there is provided a land and groove structure along 
the signal track of the disc. 
The data recorded by the record beam LB1 is read by a playback laser beam 
LB2 which comes behind the record beam LB1 on a signal track of an optical 
disc with a certain distance dL therefrom. Here, a magnitude Sp of the 
converged record laser beam LB1 and the playback laser beams LB2, LB3 can 
be incorporated in a following expression (1). 
EQU Sp=k*.lambda./N.sub.A (1), 
wherein 
.lambda.: wavelength of a laser beam; 
N.sub.A : numerical aperture in an object lens; and 
k: a constant determined according to an optical distribution at a 
numerical aperture of an object lens. 
Therefore, when a signal pit is read by a laser beam, the magnitude of an 
electrical signal reproduced becomes variable depending on the magnitude 
of a signal pit. 
As shown in FIG. 5, when the period of a signal pit is less than a half the 
magnitude Sp of the laser beam, that is, less than 0.5Sp, the playback 
signal becomes smaller. when the period of a signal pit is larger than Sp, 
the playback signal becomes maximized, thus to be less influenced by a 
period variation of a signal pit. However, when the period of a signal pit 
is larger than 0.5Sp and less than Sp, the playback signal shows a 
significant change according to the period variation of the signal pit. 
A spatial period P of a signal pit recorded in the disc is proportionate to 
a disc scanning velocity, that is, a linear velocity, as shown in a 
following expression (2). 
EQU P=T*V (2) 
(here, T: a period of a signal recorded by the record laser beam LB1) 
When a disc scanning velocity of the record laser beam LB1 shows a normal 
scanning velocity Vn, and a magnitude of a record signal read by a 
playback beam LB2 is Smin compared against a minimal signal pit period 
Pmin, the disc scanning velocity becomes larger than a normal scanning 
velocity, that is, the linear velocity Vn so that when the signal pit 
period P becomes larger than the preset minimal signal pit period Pmin the 
magnitude of a signal reproduced by the playback laser beam LB2 also 
becomes larger than Smin. 
Meanwhile, when the disc scanning velocity is less than a normal scanning 
velocity, that is, a linear velocity Vn, and thus a record signal pit 
period P is smaller than a preset minimal signal pit period Pmon, the 
magnitude of a signal reproduced by the playback laser beam LB2 becomes 
smaller than Smin. 
Accordingly, a spinning rate of an optical disc can be determined by 
detecting the magnitude of a playback signal reproduced by the playback 
beam LB2 so that a spinning rate of the optical disc can be controlled to 
maintain a constant magnitude of the playback signal for data recording. 
Also, assuming that dT denotes a delay time between a data which is a 
record channel bit signal recorded by the recording beam LB1 and a data 
which is a record channel bit signal reproduced by the playback laser beam 
LB2, a linear velocity V serving as a scanning velocity of the record beam 
LB1 is incorporated in an expression (3) as follows. 
EQU V=dL/dT (3) 
By the expression (3), a delay time dT is detected between the record 
channel bit signal serving as a recording signal and a playing channel bit 
signal to thereby determine a spinning rate of the laser disc. 
An expression (4) is also provided to obtain a delay time dT for 
controlling a disc spinning rate so as to record an information signal. 
EQU dTn=dL/Vn (4) 
By the expressions (3) and (4), a delay time is detected which occurs 
between the record channel bit signal recorded by the record beam LB1 and 
the playback channel bit signal reproduced by the playback beam LB2 to 
thereby determine and control the spinning rate of the disc. 
As in the previous description, to record a data in an optical disc, a 
record signal is decoded into a channel bit row signal appropriate to 
recording and playing-back, and a synchronous signal is periodically 
inserted in a side of the channel bit row to improve reproducibility and 
enables a random reproduction by inserting serial address signals. 
To record data in a pre-recorded disc, the previous recorded data is read 
by the playback laser beam LB3 and the read playback signal is processed 
to thereby detect a clock signal and a synchronized signal for a channel 
bit signal. 
The detected playback clock signal or the playback synchronized signal is 
compared with a standard clock signal or a standard synchronized signal to 
thereby determine and control a disc rotation speed, and then a new data 
is recorded by the record beam LB1 according to the disc spinning rate. 
That is, the disc spinning rate is controlled by a playback clock signal 
or a playback synchronized signal detected from a channel bit signal 
reproduced by the playback laser beam LB3. 
Also, to lead a new data recorded on an old data in the disc to be 
consecutively connected to the previous record signal and the previously 
synchronized signal and to lead serially recorded address signals to be 
recorded in a desired location regardless of repeated previous recording 
operation, a synchronized signal or an address signal detected from a 
signal reproduced by the playback laser beam LB3 is delayed for a certain 
time to perform a re-recording. That is, the synchronized signal or an 
address signal detected from a signal reproduced by the playing laser beam 
LB3 is delayed for a certain time so as to be re-recorded in the form of a 
synchronized signal and an address signal for a signal recorded by the 
record beam LB1. 
With reference to FIG. 6, a laser disc recording/playing apparatus 
according to the first embodiment of the present invention includes: a 
turntable 124 which accommodates an optical disc 101 placed thereon; an 
optical pick-up 102 for projecting a laser beam to the optical disc 101, 
detecting the laser beam reflected against the optical disc 101, and 
generating electrical signals a, b, c and d and radio frequency generating 
signals RF2 and RF3; a playback signal processor 103 for receiving the 
electrical signals a-d from the optical pick-up 102 and generating a focus 
control signal Fe, a tracking control signal Te and a radio frequency 
generating signal RF1; a focusing controller 104 for performing a focus 
control of the optical pick-up 102 in accordance with the focus control 
signal Fe output from the playback signal processor 103; a tracking 
controller 105 for performing a tracking control of the optical pick-up 
102 in accordance with the tracking control signal Te output from the 
playback signal processor 103; a radio frequency signal detector 106 for 
detecting the radio frequency generating signal RF3 output from the 
optical pick-up 102; a microcomputer 107 for receiving the output from the 
high frequency detector 106 and determining whether there is a previously 
recorded data in the disc to thereby control the disc player system; a 
playback signal selector 108 for generating a signal selected from the 
radio frequency generating signal RF1 output from the playback signal 
processor 103 in accordance with a control signal of the microcomputer 107 
and the radio frequency signals RF2 and RF3 output from the optical 
pick-up 102; a channel bit signal processor 109 for processing the radio 
frequency generating signal RF output from the playback signal selector 
108 and generating a playback channel bit signal CHBr, a playback channel 
bit synchronized signal SYNr and a playback channel bit clock signal CLKr; 
a digital signal processor 110 for decoding the detected channel bit row 
signal CHBr, error-correcting and generating the playback data; a standard 
clock signal generator 111 for generating a standard clock signal CLKs and 
a standard synchronized signal SYNs; a playback motor control signal 
detector 112 for comparing the standard synchronized signal SYNs output 
from the standard clock signal generator 111 with the playback channel bit 
synchronized signal SYNr output from the channel bit signal processor 109 
and detecting a playback motor control signal Mr; a record motor control 
signal detector 113 for receiving the radio frequency generating signal 
RF2 output from the optical pickup 102, the playback channel bit signal 
CHBr output from the channel bit signal processor 109 and the playback 
channel bit clock signal CLKr, and detecting a record motor control signal 
Ms; a motor control signal selector 114 for selecting a signal from the 
playback motor control signal Mr output from the playback motor control 
signal detector 112 and the record motor control signal Ms output from the 
record motor control signal detector 113, and generating a motor control 
signal Me, in accordance with the control of the microcomputer 107; a 
motor controller 115 for controlling a motor according to the motor 
control signal Me output from the motor control signal selector 114; a 
synchronous delay unit 117 for delaying the playback channel bit 
synchronous signal SYNr output from the channel bit signal processor 109 
and generating a delay synchronous signal SYNrd; a record clock selector 
118 for generating a record clock signal CLKw by selecting a signal from 
the standard clock signal CLKs output from the standard clock generator 
111 and the playback channel bit clock signal CLKr output from the channel 
bit signal processor 109, in accordance with the microcomputer 107; a 
record digital signal processor 119 for coding and decoding a record data; 
a channel bit processing transfer unit 120 for adding to the output of the 
record digital signal processor 119 the delay synchronous signal SYNrd and 
an address signal in accordance with the control of the microcomputer 107 
and generating a record channel bit signal CHBw in accordance with the 
record clock signal CLKw; light stabilizing modulator 121 for controlling 
the amount of the laser beam LB1 output from the optical pickup in 
correspondence with the record channel bit signal CHBw output from the 
channel bit processing transfer unit 120, in accordance with the control 
of the microcomputer 107; and a pair of light stabilizers 122, 123 for 
respectively controlling the amount of a corresponding one of the laser 
beams LB2, LB3 output from the optical pick-up, in accordance with the 
control of the microcomputer 107. 
The optical pick-up 102 includes: a laser diode LD1 for generating a laser 
beam LB1 in accordance with the control of the light stabilizing modulator 
121; a laser diode LD2 for generating a laser beam LB2 in accordance with 
the control of the light stabilizer 122; a laser diode LD3 for generating 
a laser beam LB3 in accordance with the control of the light stabilizer 
123; a beam splitter BS for reflecting the three beams LB1, LB2 and LB3 
each generated from the laser diodes LD1, LD2 and LD3; an object lens OL 
for converging the three laser beams reflected from the beam splitter BS 
onto a portion of a signal track of the disc; a focus activator FA and a 
tracking activator TA for moving the object lens OL in the direction of 
tracking and/or focusing so that the object lens OL can accurately 
converge the three laser beams onto a signal track of the disc; a sensor 
lens SL for converging a beam reflected against the optical disc; and 
three photo detectors PD1, PD2 and PD3 for detecting laser beam converged 
by the sensor lens SL and generating in the form of electrical signals 
which are proportionate to an amount of laser beam. 
As shown in FIG. 7, the photo detector PD1 is partitioned to form four 
photo detecting elements PD1A, PD1B, PD1C and PD1D, and the pair of 
secondary photo detecting elements PD2, PD3 are respectively provided on a 
left and a right side of the photo detector PD1. 
With reference to the accompanying drawings, the thusly composed optical 
disc recording/playing apparatus will now be described in accordance with 
the first embodiment of the present invention. 
On the turntable 124, as shown in FIG. 4, there is provided the 
free-formatted optical disc 101 having a land and groove structure along a 
track thereon. The turntable 124 controls a spinning rate of the disc 101 
by controlling the rotation speed of the motor 116. 
The three laser beams LB1, LB2 and LB3 each generated from the three laser 
diodes LD1, LD2 and LD3 are reflected from the beam splitter BS and 
converged by the object lens, and the converged three beams are projected 
on a track of the disc as shown in FIG. 4. The beams reflected against a 
signal surface of the disc 101 pass sequentially through the object lens 
OL and the beam splitter BS and are converged into the the sensor lens SL. 
The converged beams are applied to the three photo detectors PD1-PD3 to 
result in generating electrical signals which are proportionate to the 
applied light amount. 
At this time, the focus activator FA moves the object lens up and down, 
that is, along the axis thereof to thereby maintain a constant distance 
between the object lens OL and the disc 101 and obtain an optimal 
convergence. The tracking activator TA moves the object lens OL radially 
along the disc, so that the converged laser beam spots can be positioned 
along a central line of the signal track. 
The electrical signals a-d output from the four photo detecting elements 
PD1A-PD1D of the photo detector PD1 are summed (a+b+c+d) in the playback 
signal processor 103 and sent therefrom in the form of a radio frequency 
generating signal RF1. Also, the resultant of (a+c)-(b+d) is output 
therefrom in the form of a focus control signal Fe, and by (a+b)-(c+d) a 
tracking control signal Te is output. 
The photo detectors PD2, PD3 each detect radio frequency generating signals 
RF2, RF3 from the laser beams LB2, LB3 and output the same. 
Therefore, the focus controller 104 and the tracking controller 105 each 
control the focus activator FA and the tracking activator Ta of the 
optical pick-up 102 in accordance with the focus control signal Fe and the 
tracking control signal Te output from the playback signal processor 103. 
Here, a playing-back operation of a signal recorded in the optical disc 101 
will be explained as follows. 
The light stabilizing modulator 121 drives the laser diode LD1 to generate 
a certain amount of laser beam, in accordance with the control of the 
microcomputer 107. 
At this time, the light stabilizers 122, 123 control the laser diodes LD2, 
LD3 to have the value "0" of a laser output, in accordance with the 
control of the microcomputer 107. 
The laser beam LB1 from the laser diode LD1 passes through the beam 
splitter BS and the object lens OL and is placed on a signal track of the 
disc 101, and the beam reflected against the signal surface of the disc 
101 passes through the object lens OL, the beam splitter BS and the sensor 
lens SL and is converged. As a result, the photo detector PD1 outputs 
electrical signals a-d proportionately to the incident light amount. 
The playback signal processor 103 receives the electrical signals a-d and 
generates the radio frequency generating signal RF1, the focus control 
signal Fe and the tracking control signal Te. The playback signal selector 
108 selects a radio frequency generating signal RF1 detected from the 
photo detector PD1, in accordance with the control of the microcomputer 
107. 
The selected radio frequency generating signal RF1 is detected as a 
playback channel bit signal CHBr in the channel bit signal processor 109, 
from which the playback channel bit synchronous signal SYNr and a clock 
signal CLKr are detected respectively. 
At this time, the playback channel bit synchronous signal SYNr output from 
the channel bit signal processor 109 is applied along with the standard 
synchronous signal SYNs output from the standard clock generator 111 to 
the playback motor control signal detector 112 to thereby output the 
playback motor control signal Mr. The motor control signal selector 114 
outputs the playback motor control signal Mr in the form of a motor 
control signal Me to thereby control the spinning rate of the disc 101, in 
accordance with the control of the microcomputer 107. 
The playback channel bit signal CHBr output from the channel bit signal 
processor 109 is decoded and error-corrected in the digital signal 
processor 110 and output therefrom. 
The operation of recording a signal on the optical disc will be described. 
In accordance with the control of the microcomputer 107, the light 
stabilizer 123 controls the laser diode LD3 to output a playback light 
amount, and the photo detector PD3 detects a radio frequency generating 
signal RF3 from a laser beam reflected from the disc. 
The detected radio frequency playback signal RF3 passes through the radio 
frequency signal detector 106 and applied to the microcomputer 107 which 
in turn judges whether the disc 101 is data-recorded or blank in 
accordance with a detection signal of the radio frequency signal detector 
106. 
That is, because the laser beam LB3 output from the laser diode LD3 is 
placed in front of the record beam LB1 on a track of the disc, if a radio 
frequency signal RF3 is detected from the photo detector PD3 which detects 
a reflected beam of the laser beam LB3, the optical disc 101 is 
data-recorded, and if the radio frequency signal RF3 is not detected, the 
disc 101 is blank, that is, data-free. 
When a data signal is previously recorded in the disc 101, the playback 
signal selector 108 selectively outputs the radio frequency signal RF3 
output from the photo detector PD3 in accordance with the control of the 
microcomputer 107, and the channel bit signal processor 109 detects from 
the radio frequency generating signal RF3 the playback channel bit signal 
CHBr, the playback channel bit synchronous signal SYNr and a clock signal 
CLKr, respectively. 
Here, the record clock selector 118 selects the playback channel bit clock 
signal CLKr output from the channel bit signal processor 109 and outputs a 
record clock signal CLKw to the channel bit processing transfer unit 120, 
and the synchronous delay unit 117 delays for a certain time the playback 
channel bit synchronous signal SYNr output from the channel bit signal 
processor 109 and outputs a delay synchronous signal SYNrd. 
The applied record data is processed using a proper format in the record 
signal processor 119, and an error-correction detecting code is added 
thereto and coded into a signal which is appropriate to be recorded in the 
disc 101. In accordance with the control of the microcomputer 107, the 
channel bit processing transfer unit 120 adds to the output of the record 
digital signal processor 119 the delay synchronous signal and an address 
signal output from the synchronous delay unit 117 and outputs the channel 
bit signal CHBw to the light stabilizing modulator 121 according to the 
record clock signal CLKw. 
Then, the light stabilizing modulator 121 controls the amount of light 
emitted from the laser diode LD1 according to the record channel bit 
signal CHBw, thereby recording a signal on a track of the disc 101. 
The playback motor control signal detector 112 outputs a playback motor 
control signal Mr according to a playback channel bit synchronous signal 
SYNr output from the channel bit signal processor 109 and a standard 
synchronous signal SYNs output from the standard clock signal generator 
111, and in accordance with the control of the microcomputer 107 the motor 
control signal selector 114 outputs a motor control signal Me from the 
playback motor control signal Mr to thereby control a spinning rate of the 
optical disc 101. 
When the disc 101 is previously data-recorded, a new data is recorded on 
the old data by adjusting a position of the synchronous signal to the old 
data density. At this time, the laser diode LD2 has a beam output value 
"0" in accordance with the control of the light stabilizer 122. 
Meanwhile, when the disc 101 is provided for an initial recording, that is, 
blank and data-free, the playback signal selector 108 selectively outputs 
the radio frequency generating signal RF2 output from the photo detector 
PD2 in accordance with the control of the microcomputer 107, and the 
channel bit signal processor 109 detects a playback channel bit signal 
CHBr, a playback channel bit synchronous signal SYNr and a clock signal 
CLKr in accordance with the radio frequency generating signal RF2. 
That is, a signal is recorded by the laser beam LB1 in accordance with the 
laser diode LD1, a radio frequency generating signal RF2 is obtained by 
the laser beam LB2 delayed for a certain distance dL and a certain time 
dTn from the beam LB1, and by processing the radio frequency generating 
signal RF2 a playback channel bit signal CHBr and a channel bit clock 
signal CLKr are obtained. 
The record clock selector 118 selects the standard clock signal CLKs output 
from the standard clock generator 111 in accordance with the control of 
the microcomputer 107 and outputs a record clock signal CLKw to the 
channel bit processing transfer unit 120. 
A record data is output from the record digital signal processor 119 in the 
form of a signal appropriate to record in the disc 101, and the channel 
bit processing transfer unit 120 adds a synchronous signal and an address 
signal to the output of the digital signal processor 111 in accordance 
with the control of the microcomputer 107, generates a record channel bit 
signal CHBw and outputs the signal CHBw to the light stabilizer 121 in 
accordance with the record clock signal CLKw. At this time, the 
synchronous signal is generated in the channel bit processing transfer 
unit 120 in accordance with the control of the microcomputer 107. 
Then, the light stabilizing modulator 121 controls the light amount of the 
laser diode LD1 to thus record a signal on the track of the disc 101. 
The record motor control signal detector 113 processes the playback channel 
bit clock signal CLKr output from the channel bit signal processor 109 and 
the radio frequency generating signal RF2 output from the playback signal 
selector 108, and outputs a record motor control signal Ms. The motor 
control signal selector 118 outputs the record motor control signal Ms in 
the form of a motor control signal Me in accordance with the control of 
the microcomputer 107 so as to control a spinning rate of the disc 101. 
The playback channel bit synchronous signal SYNr reproduced in the channel 
bit signal processor 109 together with the standard synchronous signal 
SYNs output from the standard clock generator 111 is applied to the 
playback motor control signal detector 112 to be thereby employed to 
output a playback motor control signal Mr. 
When the disc 101 is not data-recorded, that is, data-free, the 
microcomputer 107 controls the light stabilizer 123 to thus lead to a 
light amount "0" of the laser diode LD3. 
With reference to FIG. 8, the operation of the microcomputer 107 will now 
be described. 
Initially, when playing-back a signal recorded in the disc 101, the 
microcomputer 107 controls a playback signal selector 108, selects the 
radio frequency generating signal RF1 output from the photo detector PD1, 
controls the motor control signal selector 114, selects the playback motor 
control signal Mr output from the playback motor control signal detector 
112, and controls the motor 116.(31, 32) 
When recording a signal in the disc 101, by using the output of the radio 
frequency signal detector 106 the signal is judged whether it is initially 
being recorded. (33, 34) 
In the case of an initial recording, the playback signal selector 108 is 
controlled to select the radio frequency generating signal RF2 output from 
the photo detector PD2. The motor control signal selector 114 is 
controlled to select the record motor control signal Ms output from the 
record motor control signal detector 113 to thus control the motor 116. 
The record clock selector 118 is controlled to select the standard clock 
signal CLKs output from the standard clock generator 111. The channel bit 
processing transfer unit 120 is controlled so that an externally applied 
synchronous signal is ignored and an internal synchronous signal is 
generated. (35) 
If the recording is judged to be a re-recording, the playback signal 
selector 108 is controlled to select the radio frequency generating signal 
RF3 output from the photo detector PD3. The motor control signal selector 
114 is controlled to select the playback motor control signal Mr output 
from the playback motor control signal detector 112 to thus control the 
motor 116. The record clock selector 118 is controlled to select the 
playback channel bit clock signal CLKr output from the channel bit signal 
processor 109. The channel bit processing transfer unit 120 is controlled 
to employ the delay synchronous signal SYNrd output from the synchronous 
delay unit 117. (36, 37) 
A detailed composition of the optical disc recording/playing apparatus of 
FIG. 6 according to the present invention will be explained as follows. 
As shown in FIG. 9, the first embodiment of the record motor control signal 
detector 113 includes: a channel bit pattern detector 125 for detecting 
from the playback channel bit signal CHBr a positive high frequency 
pattern detecting signal FSYp+ and a negative high frequency pattern 
detecting signal FSYp-, in accordance with the playback channel bit clock 
signal CLKr output from the channel bit signal processor 109; an analog 
shifter 126 for analog-shifting the radio frequency generating signal RF2 
output from the optical pickup 102 in accordance with the playback channel 
bit clock signal CLKr; an analog shift unit 127 for analog-shifting the 
signal output from the analog shift unit 126 in accordance with the 
playback channel bit clock signal CLKr; a differential amplifier 128 for 
differentially amplifying the output of the analog shift unit 127 which 
output is applied to an uninverted input thereof and the output of the 
analog shift unit 126 which output is applied to an inverted input 
thereof; a differential amplifier 129 for differentially amplifying the 
output of the analog shift unit 127 which output is applied to an inverted 
input thereof and the output of the analog shift unit 126 which output is 
applied to an uninverted input thereof; a sampler 131 for sampling the 
output of the differential amplifier 129 in accordance with the negative 
high frequency pattern detecting signal FSYp-; a differential amplifier 
132 for generating a motor control signal Ms by differentially amplifying 
the output of the sampler 130 or the sampler 131 which output is applied 
to an uninverted input thereof and the standard signal Smin applied to an 
inverted input thereof. 
The analog shift units 126, 127 are composed of a different number of 
analog shifters AS from each other. 
Here, a high frequency bit array pattern is composed of a positive high 
frequency pattern and a negative high frequency pattern. In an EFM 
modulating method, the positive high frequency pattern is incorporated in 
"011100011", and the negative high frequency pattern is in "10001110". 
The analog shift unit 126 analog-shifts the high frequency generating 
signal RF2 to a playback channel bit clock signal CLKr which period is 
obtained by adding "1" to a minimal number Nmin of identical serial bits 
in a channel bit row and being divided by 2{(Nmin+1)/2}, and the analog 
shift unit 127 shifts the output of the analog shift unit 126 to a minimal 
number Nmin of the playback channel bit clock signal CLKr. Here, "1" is 
added to a minimal number Nmin of identical serial bits in a channel bit 
row in order to obtain a larger natural number. 
The operation of the thusly composed record motor control signal detector 
113 will be described, referring to FIGS. 10A-10F wherein FIG. 10A denotes 
a timing wave diagram of the playback channel bit signal CHBr and FIG. 10D 
denotes a timing diagram of the radio frequency generating signal RF2. 
The record motor control signal detector 113 as described above detects the 
magnitude Vs of a high frequency generating signal, that is, a playback 
signal of a minimal pit recorded in the disc, and compares the detected 
signal with a standard playback signal Smin which is preset, so that a 
rotation speed of the motor can be judged and a motor control signal can 
be obtained. 
The channel bit pattern detector 125 detects the positive high frequency 
pattern formed of "01110001" and the negative high frequency pattern 
formed of "100011101" in a high frequency bit row pattern of the playback 
channel bit signal CHBr as in FIG. 10A, that is, in an EFM modulating 
method, and outputs a positive high frequency pattern detecting signal 
FSYp+ as in FIG. 10C and a negative high frequency pattern detecting 
signal FSYp- as in FIG. 10B, in accordance with the playback channel bit 
clock signal CLKr output from the channel bit signal processor 109. 
The analog shift unit 126 delays a radio frequency generating signal RF2 as 
in FIG. 10D to a period (Nmin+1)/2 of the playback channel bit clock 
signal CLKr, and the analog shift unit 127 shifts the output of the analog 
shift unit 127 so as to have a period Nmin of the playback channel bit 
clock signal CLKr in accordance with the playback channel bit clock signal 
CLKr. Here, Nmin denoting a minimal number of identical serial bits in a 
channel bit row has a value 3. 
The analog shift unit 126 in the EFM modulating method delays a radio 
frequency generating signal RF2 in two periods of the channel bit clock 
signal CLKr, and the analog shift unit 127 analog-shifts the output of the 
analog shifter unit 126 in three periods of the playback channel bit clock 
signal CLKr. In FIG. 10E, "a" denotes an output of the analog shifter (AS) 
126, and "b" denotes an output of the analog shift unit 127. 
The differential amplifiers 128, 129 differentially amplify the output of 
the analog shift units 126, 127 respectively and output differential 
signals having different polarities. The sampler 130 samples the output of 
the differential amplifier 128 in accordance with the positive high 
frequency pattern detecting signal FSYp+, and the sampler 131 samples the 
output of the differential amplifier 129 in accordance with the negative 
high frequency pattern detecting signal FSYp-. 
The signals sampled in the samplers 130, 131 are detected in the same 
magnitude as the positive and negative bit pattern polarities, that is, in 
a magnitude of a high frequency generating signal, and applied to the 
uninverted input to the differential amplifier 132 which differentially 
amplifies a standard signal Smin applied to an inverted input thereto to 
thereby output a record motor control signal Ms as in FIG. 10F. 
As shown in FIG. 11, the channel bit pattern detector 125 includes: an AND 
gate 125-5 for generating the positive high frequency pattern detecting 
signal FSYp+ by ANDing a plurality of shift resisters 125-1 . . . 125-4 
each serially connected thereto so as to shift the playback channel bit 
signal CHBr, the playback channel bit signal CHBr and the shift resisters 
125-1 . . . 125-4; and an AND gate 125-6 for generating the negative high 
frequency pattern detecting signal FSYP+ by ANDing the playback channel 
bit signal CHBr and the output of the shift resisters 125-1 . . . 125-4, 
in accordance with the playback channel bit clock signal CLKr output from 
the channel bit signal processor 109. 
As shown in FIG. 12, the analog shifter AS of the analog shift units 126, 
127 includes: a switch 133 for generating a radio frequency generating 
signal RF2; an amplifier 134 for amplifying the output of the switch 133; 
a switch 135 the output of the amplifier 134 in accordance with the 
inverted playback channel bit clock signal CLKr; and an amplifier 136 for 
amplifying the output of the switch 135, in accordance with the playback 
channel bit clock signal CLKr output from the channel bit signal processor 
109. 
The shift transistors 125-1 . . . 125-4 shifts the playback channel bit 
signal CHBr by a bit to the right in the channel bit row in accordance 
with the period of the playback channel bit clock signal CLKr output from 
the channel bit signal processor 109. 
The AND gate 125-5 compares a number 2Nmin+2 of channel bits serially 
applied thereto with a bit array pattern, that is, the negative high 
frequency pattern "10001110", and "1" is output as the negative high 
frequency pattern FSYp- if the compared values are identical, and "0" is 
output if different. The AND gate 125-6 compares a number 2Nmin +2 of 
channel bits serially applied thereto with the positive high frequency 
pattern "01110001", and "1" is output as the positive high frequency 
pattern FSYp+ if the compared values are identical, and "0" is output if 
different. 
The analog shifter AS delays the radio frequency generating signal RF2 by a 
clock signal, in accordance with the playback channel bit clock signal 
CLKr output from the channel bit signal processor 109. 
As shown in FIG. 13, the second embodiment of the record motor control 
signal detector 113 of FIG. 6 includes: a channel bit pattern detector 137 
for detecting a half cycle bit array pattern of the high frequency signal 
from the playback channel bit signal CHBr, generating a positive half 
cycle high frequency pattern detecting signal HSYp+ and a negative half 
cycle high frequency pattern detecting signal HSYp-, detecting a bit array 
pattern of a low frequency signal from the playback channel bit signal 
CHBr, and generating a positive low frequency pattern detecting signal 
HY1+ and a negative low frequency pattern detecting signal HY1-, in 
accordance with the playback channel bit clock signal CLKr output from the 
channel bit signal processor 109; a pair of delay units 138, 139 for 
sequentially delaying the radio frequency generating signal RF2 output 
from the optical pickup in accordance with the playback channel bit clock 
signal CLKr; a pair of samplers 140, 141 for respectively sampling the 
output of the delay unit 138 to a positive half cycle high frequency 
pattern detecting signal HYSp+ and a negative half cycle high frequency 
pattern detecting signal HYSp-; a pair of samplers 142, 143 for 
respectively sampling the output of the delay unit 139 to a positive half 
cycle low frequency pattern detecting signal HY1+ and a negative half 
cycle low frequency pattern detecting signal HY1-; a differential 
amplifier 144 for differentially amplifying the output of the samplers 
140, 141; a differential amplifier 145 for differentially amplifying the 
output of the samplers 142, 143; and a differential amplifier 146 for 
differentially amplifying the output of the samplers 144, 145. 
The channel bit pattern detector 137 includes: a plurality of shift 
resisters 137-1 . . . 137-4 connected serially to each other to thereby 
shift the playback channel bit signal CHBr; an AND gate 137-5 for ANDing 
the playback channel bit signal CHBr and the output of the shift resisters 
137-1 . . .137-4 to thereby output a positive half cycle high frequency 
pattern detecting signal HSYp+; an AND gate 137-6 for ANDing the playback 
channel bit signal CHBr and the output of the shift resisters 137-1 . . . 
137-4 to thereby output a negative half cycle high frequency pattern 
detecting signal HSYp-; an AND gate 137-7 for ANDing the playback channel 
bit signal CHBr and the output of the shift resisters 137-1 . . . 137-4 to 
thereby output a positive half cycle low frequency pattern detecting 
signal HS1+; and an AND gate 137-8 for ANDing the playback channel bit 
signal CHBr and the output of the shift resisters 137-1 . . . 137-4 to 
thereby output a negative half cycle low frequency pattern detecting 
signal HS1-. 
The high frequency half cycle bit array pattern in the EFM method is 
composed of a positive half cycle high frequency pattern having "01110" 
and a negative half cycle high frequency pattern having "10001", and the 
low frequency signal bit array pattern is composed of a positive low 
frequency bit array pattern having "11111111" and a negative low frequency 
signal bit array pattern having "00000000". 
The delay unit 138 delays the radio frequency generating signal RF2 to 
correspond to the period of a playback channel bit clock signal CLKr which 
period is obtained by adding "1" to the number Nmin of identical serial 
bits in a high frequency bit pattern, and the delay unit 139 delays the 
radio frequency generating signal RF2 to correspond to the period of a 
playback channel bit clock signal CLKr which period is obtained by adding 
"1" to the number Nmin of identical serial bits in a low frequency bit 
pattern. 
The second embodiment of the thusly composed record motor control signal 
detector 113 will be described with reference to the accompanying 
drawings. 
The channel bit signal CHBr is shifted bit by bit to the right by the shift 
registers 137-1 . . . 137-4 in a period of the playback channel bit clock 
signal CLKr output from the channel bit signal processor 109. 
If serially applied channel bits which are output from the playback channel 
bit signal CHBr and the shift registers 137-1, . . . ,137-4 are identical 
to a preset bit array pattern which is the positive half cycle high 
frequency pattern "01110", the AND gate 137-5 outputs "1" as the positive 
half cycle high frequency pattern detecting signal HSYp+, and if not 
identical the AND gate 137-5 outputs "0". 
Also, if serially applied channel bits are identical to a preset bit array 
pattern which is the negative half cycle high frequency pattern "10001", 
the AND gate 137-6 outputs "1" as the negative half cycle high frequency 
pattern detecting signal HSYp-, and if not identical the AND gate 137-5 
outputs "0". 
Further, if serially applied channel bits are identical to a preset bit 
array pattern which is the negative half cycle low frequency pattern 
"11111111", the AND gate 137-7 outputs "1" as the positive half cycle low 
frequency pattern detecting signal HS1+, and if not identical the AND gate 
137-7 outputs "0", and if serially applied channel bits are identical to a 
preset bit array pattern which is the negative half cycle low frequency 
pattern "00000000", the AND gate 137-8 outputs "1" as the negative-half 
cycle-low. frequency pattern detecting signal HS1-, and if not identical 
the AND gate 137-8 outputs 11011. 
The delay unit 138 receives the radio frequency generating signal RF2 and 
delays the signal RF2 in a period (Nmin+1)/2 of the playback channel bit 
clock signal CLKr relative to the high frequency signal, and the delay 
unit 139 receives the output of the delay unit 138 and delays for output 
the signal RF2 in a period (N+1)/2 of the playback channel bit clock 
signal CLKr. Here, in the EFM modulating method, the number N of identical 
serial bits of a low frequency signal bit pattern ranges from 8 to 11. 
The pair of samplers 140, 141 each sample/hold the output of the delay unit 
138 to a positive half cycle high frequency pattern detecting signal HYSp+ 
and a negative half cycle high frequency pattern detecting signal HYSp- to 
thereby detect a level of the playback signal, and the pair of samplers 
142, 143 respectively sample/hold the output of the delay unit 139 to a 
positive half cycle low frequency pattern detecting signal HY1+ and a 
negative half cycle low frequency pattern detecting signal HY1- to thereby 
detect a level of the playback signal. 
The differential amplifier 144 differentially amplifies the output of the 
amplifier 140 applied to an inverted input thereto and the output of the 
amplifier 141 applied to an uninverted input thereto to thereby output the 
magnitude Vs of the high frequency generating signal, and the differential 
amplifier 145 differentially amplifying the output of the sampler 142 
applied to an uninverted input thereto and the output of the amplifier 143 
applied to an inverted input thereto to thereby output the magnitude Vmax 
of the low frequency generating signal. At this time, resistances R1, R2 
partially press the output of the differential amplifier 145 according to 
the resistance ratio. 
The differential amplifier 146 differentially amplifies the magnitude Vs of 
the high frequency generating signal applied to the uninverted input 
thereto and the magnitude Vmax of the low frequency generating signal 
applied to the inverted input thereto, to thereby output a record motor 
control signal Ms. Here, the ratio Vs/Vmax (=R2/(R1+R2)) of the magnitude 
Vs of the high frequency generating signal to the magnitude Vmax of the 
low frequency generating signal is stably maintained. 
Meanwhile, the record channel bit signal CHBr recorded by the laser beam 
LB1 is delayed for a certain time dT (=dL/V) and output in the form of a 
playback channel bit signal CHBr after the radio frequency generating 
signal RF2 is processed by the laser beam LB2. As a result, the time delay 
of dT occurs between the record channel bit signal CBHr and the playback 
channel bit signal CHBr, so that if a normal scanning speed or a linear 
speed Vn is maintained for the disc 101 the time delay between the two 
signals become dTn and if the time delay is controlled to be dTn the 
spinning rate of the disc 101 can be constantly controlled. 
FIG. 14 showing the second embodiment of the optical disc recording/playing 
apparatus according to the present invention is identical to the first 
embodiment of FIG. 6 with the exception of the record motor control signal 
detector 113-1. 
The record motor control signal detector 113-1 receives a record channel 
bit signal CHBw output from the channel bit processing transfer unit 120, 
a playback channel bit synchronous signal SYNr output from the channel bit 
signal processor 109 and a record clock signal CLKw output from the record 
clock selector 118, and outputs a record motor control signal Ms. 
As shown in FIG. 15, the record motor control signal detector 113-1 
includes: a synchronous pattern detector 147 for detecting a synchronous 
pattern by receiving the record channel bit signal CHBw output from the 
channel bit processing transfer unit 120 and generating a positive 
synchronous pattern detecting signal SY+ and a negative synchronous 
pattern detecting signal SY-, in accordance with the record clock signal 
CHBw output from the record clock selector 118; an OR gate 148 for ORing 
the positive synchronous pattern detecting signal SY+ and the negative 
synchronous pattern detecting signal SY- each output from the synchronous 
pattern detector 147 and generating a record synchronous signal SYNw; an 
RS flip-flop 149 for receiving the output from the OR gate 148 through a 
set input S thereof and the playback channel bit synchronous signal SYNr 
through a reset input R thereof; an integrator 150 for integrating the 
output from the RS flip-flop 149; and a differential amplifier 151 for 
differentially amplifying the output of the integrator 150 applied to an 
uninverted input thereof and a supply voltage Vref applied to an inverted 
input thereof and generating an motor control signal Ms. 
As shown in FIG. 16, the synchronous pattern detector 147 includes: a 
plurality of shift resisters 147-1, . . . ,147-4 connected serially to 
each other to thereby shift the playback channel bit signal CHBr; an AND 
gate 147-5 for ANDing the playback channel bit signal CHBr and the output 
of the shift resisters 147-1, . . . ,147-4 to thereby output a positive 
synchronous pattern detecting signal SY+; and an AND gate 1476 for ANDing 
the playback channel bit signal CHBr and the output of the shift resisters 
147-1, . . . ,147-4 to thereby output a negative synchronous pattern 
detecting signal SY-. 
The operation of the thusly composed record motor control signal detector 
113-1 will be described. 
The synchronous pattern detector 147 of the record motor control signal 
detector 113-1, in accordance with the record clock signal CLKw output 
from the record clock selector 118, detects from the record channel bit 
signal CHBw output from the channel bit processing transfer unit 120 a 
positive synchronous pattern formed of "00001111" according to the EFM 
method and a negative synchronous pattern formed of "11110000" to thereby 
output the positive synchronous pattern detecting signal SY+ and the 
negative synchronous pattern detecting signal SY-. 
In accordance with the record clock CLKw, the plurality of shift registers 
147-1, . . . ,147-4 shift by one bit the array of the channel-bit signals 
CHBw to the right. If the serially applied channel bits are identical to 
the positive synchronous pattern "00001111" which is previously set, the 
AND gate 147-5 outputs "1" serving as a positive synchronous pattern 
detecting signal SY+, and if not identical the gate 147-5 outputs "0". 
Also, if the serially applied channel bits are identical to the negative 
synchronous pattern "11110000" which is previously set, the AND gate 147-6 
outputs "1" serving as a negative synchronous pattern detecting signal 
SY-, and if not identical the gate 147-6 outputs "0". 
Then, the positive synchronous pattern detecting signal SY+ and the 
negative synchronous pattern detecting signal SY- each output from the AND 
gates 147-5, 147-6 are ORed in the OR gate 148 which in turn outputs a 
record synchronous signal SYNw to the RS flip-flop 149 which is reset in 
accordance with the playback channel bit synchronous signal SYNr output 
from the channel bit signal processor 109. 
Therefore, as the RS flip-flop 149 is set/reset, the output Q of the 
flip-flop 149 is integrated in the integrator 150 and output therefrom in 
the form of a signal voltage Vd proportionate to a delay time, and the 
signal voltage Vd applied to an uninverted input to the differential 
amplifier 151 is differentially amplified with the standard voltage Vref 
applied to an inverted input thereto to thereby output a motor control 
signal Ms. 
When there occurs a time delay dT between the record channel bit signal 
CHBw and the playback channel bit signal CHBr, the identical time delay dT 
occurs between the record channel bit synchronous signal SYNw detected 
from each channel bit signal and the playback channel bit synchronous 
signal SYNr. 
So, the RS flip-flop 149 set/reset in accordance with the record channel 
bit signal synchronous signal SYNw and the record channel bit synchronous 
signa SYNr generates a pulse signal, which passes through the integrator 
150 to be thereby incorporated in the signal voltage Vd which is 
proportionate to the delay time. At this time, when maintaining a normal 
scanning rate, that is, a linear scanning velocity of the disc 101, the 
standard voltage Vref denotes a detection voltage serving as a delay time 
in the record channel bit synchronous signal SYNw and the playback channel 
bit synchronous signal SYNr. 
FIG. 17 showing the third embodiment of the optical disc recording/playing 
apparatus according to the present invention remains identical to FIG. 6 
with the exception of a record motor control signal detector 113-2 which 
outputs a record motor control signal Ms so as to control the motor by 
receiving the record channel bit signal CHBw output from the channel bit 
processing transfer unit 120, the playback channel bit signal CHBr output 
from the channel bit signal processor 109 and the record clock signal CLKw 
output from the record clock selector 118. 
As shown in FIG. 18, the record motor control signal detector 113-2 
includes: shift register units 152, 153, 154 each for delaying for a 
certain time the record channel bit signal CHBw output from the channel 
bit processing transfer unit 120, in accordance with the record clock CLKw 
output from the record clock selector 118; an exclusive OR gate 155 for 
exclusively ORing the output from the shift register 152 and the playback 
channel bit signal CHBr output from the channel bit signal bit processor 
109; an integrator 156 for integrating the output from the exclusive OR 
gate 155 and generating a signal voltage proportionate to the correlation 
between a pair of signals which are obtained by dTn- a time-delaying a 
playback signal and a record signal; an exclusive OR gate 157 for 
exclusively ORing the output from the shift register 153 and the playback 
channel bit signal CHBr; an integrator 158 for integrating the output from 
the exclusive OR gate 157 and generating a signal voltage proportionate to 
the correlation between a pair of signals which are obtained by dTn 
time-delaying a playback signal and a record signal; an exclusive OR gate 
159 for exclusively ORing the output from the shift register 154 and the 
playback channel bit signal CHBr; an integrator 160 for integrating the 
output from the exclusive OR gate 159 and generating a signal voltage 
proportionate to the correlation between a pair of signals which are 
obtained by dTn+ a time-delaying a playback signal and a record signal; 
and a differential amplifier 160 for differentially amplifying the output 
from the integrator 156 which is applied to an inverted input thereto and 
the output from the integrator 160 which is applied to an uninverted input 
thereto to thereby generate a motor control signal Ms. 
Each of the shift register units 152, 153, 153 are sequentially composed of 
a plurality of shift registers 152-1, 152-2; 153-1, 153-2; 154-1, 154-2. 
The operation of the record motor control signal detector 113-2 will now be 
described. 
First, the plurality of shift registers provided in the shift register 
units 152, 153, 154 delay the record channel bit signal CHBw to correspond 
to a period DBn having a certain bit, in accordance with the record clock 
signal CLKw. 
That is, when the record channel bit signal CHBwn which is delayed-output 
from the shift register unit 153 is centered, the shift register units 
152, 154 provided in the rear and front of the unit 153 generates a 
delayed record channel bit signal CHBwn-, CHBwn+, respectively. 
Also, the record channel bit signal CHwn- output from the shift register 
unit 152 denotes a signal delayed in a DBn-DB period for a delay time dTn- 
a serving as a clock signal period of the channel bit signal. The record 
channel bit signal CHBwn output from the shift register unit 153 denotes a 
signal delayed in a DBn period for a delay time dTn serving as a clock 
signal period of the channel bit signal. The record channel bit signal 
CHBwn+ output from the shift register unit 154 denotes a signal delayed in 
a DBn+DB period for a delay time dTn+ a serving as a clock signal period 
of the channel bit signal. 
As a result, the record channel bit signal CHBwn- output from the shift 
register unit 152 is exclusively ORed with the playback channel bit signal 
CHBr in the exclusive OR gate 155, and integrated in the integrator 156 to 
thereby output a signal voltage which is delayed for a dTn- a time which 
is proportionate to the correlation between the record channel bit signal 
CHBwn- and the playback channel bit signal CHBr as shown in FIG. 19A. 
The record channel bit signal CHBwn+ output from the shift register unit 
154 is exclusively ORed with the playback channel bit signal CHBr in the 
exclusive OR gate 159, and integrated in the integrator 160 to thereby 
output a signal voltage which is delayed for a dTn+ a time which is 
proportionate to the correlation between the record channel bit signal 
CHBwn+ and the playback channel bit signal CHBr as shown in FIG. 19C. 
Also, the record channel bit signal CHBwn output from the shift register 
unit 153 passes through the exclusive OR gate 159 and the integrator 160 
and is output in the form of a signal voltage as shown in FIG. 19B. 
Therefore, the signal voltage output from the integrator 156, 158, 160 have 
correlations Rxn-, Rxn, Rxn+ as shown in FIGS. 19A-19C. 
Here, when the motor 116 maintains a normal recording velocity Vn the pair 
of channel bit signals CHBwn, CHBr has a maximum value of correlation, and 
when the record velocity deviates from the normal velocity Vn to thereby 
cause a velocity gap, the correlation will decrease according to the 
velocity gap and the value of the correlation gradually decreases. 
The correlation values Rxn-, Rxn+ show a variation according to a time 
delay, and the correlation values Rxn-, Rxn+ output from the integrator 
156, 160 are differentially amplified in the differential amplifier 161 to 
thereby cause to generate the record motor control signal Ms. 
FIG. 20 shows the fourth embodiment of the optical disc recording/playing 
apparatus according to the present invention, wherein the optical 
stabilizers 122, 123 are excluded from FIG. 6 showing the first embodiment 
of the optical disc recording/playing apparatus according to the present 
invention, and an optical pick-up 202 and signal shapers 203, 204 are 
differently provided. 
The optical pick-up 202 includes: a laser diode LD for generating a laser 
beam by the control of the light stabilizing modulator 121; a grating GR 
for branching the laser beam output from the laser diode LD into laser 
beams LB1, LB2, LB3; a beam splitter BS for reflecting the beams LB1, LB2, 
LB3 generated from the grating GR; an object lens OL for converging the 
three laser beams reflected from the beam splitter BS onto a portion of a 
signal track of the disc; a focus activator FA and a tracking activator TA 
for moving the object lens OL in the direction of tracking and/or focusing 
so that the object lens OL can accurately converge the three laser beams 
onto a signal track of the disc; a sensor lens SL for converging the beams 
which have passed through the beam splitter BS after being reflected from 
the disc; and photo detectors PD1, PD2, PD3. 
The signa shapers 203, 204 shape radio frequency generating signals RF2', 
RF3' reproduced by the beams LB2, LB3 of the optical pick-up 202 in 
accordance with a light amount control signal output from the light 
stabilizing modulator 121 to thereby output the radio frequency generating 
signal RF2, RF3 by removing a signal generated by a light amount 
modulation. 
The operation of the fourth embodiment of the optical disc 
recording/playing apparatus according to the present invention will be 
described by selecting the difference from the first embodiment thereof. 
Different from the conventional optical disk playing-back apparatus which 
employs three laser beams to detect a tracking control signal, the present 
invention employing a recording disc having a land and groove structure 
can easily adapt a push-pull method in accordance with a single beam. 
The grating GR grates the light emitted from the laser diode LD to thereby 
multiply to the three beams LB1, LB2, LB3. 
Here, when the luminous amount of the laser diode LD is modulated to 
modulate the light amount of the record laser beam LB1, the light amount 
of the playback laser beams LB2, LB3 are also concurrently varied, and 
because the radio frequency signals RF2', RF3' in accordance with the 
playback beams LB2, LB3 are mixed with a record signal and a playback 
signal as shown in FIG. 21B, the signal generated during modulation of 
light amount must be removed. 
Therefore, from the radio frequency generating signals RF2', RF3' applied 
to the signal shapers 203, 204 a signal generated by a light modulation 
serving as a record signal is removed to thereby cause the signal shapers 
203, 204 to output the radio frequency generating signals RF2, RF3. 
As shown in FIG. 22, the first embodiment of the signal shapers 203, 204 
includes: resistances R3, R4 connected parallel to an input to the radio 
frequency signals RF2', RF3'; and a switch 162 to a fixed terminal c of 
which a control signal is connected and to another fixed terminal d of 
which a node between the resistances R3, R4 is connected, to thereby 
output the radio frequency generating signals RF2, RF3 in accordance with 
a control signal output from the light stabilizing modulator 121. Here, 
the control signal applied to the switch 162 denotes a light amount signal 
serving as a power signal for turning on the laser diode LD of the optical 
pick-up 202. 
As the light amount of the playback laser beams LB2, LB3 is variable, the 
radio frequency generating signals RF2', RF3' are generated in the form of 
a gain inversely proportionate to the light amount of the playback laser 
beams LB2, LB3. Also, when the ratio frequency generating signals RF2', 
RF3' are amplified to be inversely proportionate to the light amount of 
the laser diode LD, the radio frequency generating signals RF2, RF3 having 
a constant gain will be obtained. 
That is, if a radio frequency signal amplifier is provided which can 
continuously change an amplified gain, the radio frequency generating 
signals RF2, RF3 having a constant gain is obtained by controlling the 
gain of the radio frequency generating signals RF2', RF3' in accordance 
with a control signal, that is, a light amount signal of the laser diode 
LD. However, when the variation of the light amount is not continuous, and 
instead the recording occurs in the form of a phase variation for 
recording/erasing of data by changing the recording light in two steps as 
shown in FIG. 21A, the radio frequency generating signals RF2, RF3 having 
constant gain can be obtained by the switch 162 as shown in FIG. 22. 
Assuming that a recording amount in modulating a recording light denotes 
LPrec and an erasing light amount denotes LPera to perform a two-step 
light modulation, there is obtained an expression as follows. 
EQU LPera/LPrec=R4/(R3+R4) 
When the resistances R3, R4 are set and the light is recorded the record 
radio frequency generating signal RFrec is selected, and when the switch 
162 is controlled so that when the light is erased the erasing radio 
frequency generating signal RFera is selected, the radio frequency 
generating signal RF having a constant gain is obtained. 
As shown in FIG. 23, the second. embodiment of the signal shapers 203, 204 
includes a differential amplifier 163 for receiving to an uninverted input 
thereof the radio frequency generating signal RF2', RF3' reproduced by the 
laser beams LB2, LB3, and to an inverted input thereof a light amount 
signal output from the light stabilizing modulator 121 to thereby output a 
high frequency generating signals RF2, RF3. 
The differential amplifier 163 differentially amplifies the radio frequency 
generating signals RF2', RF3' and the light amount signal applied to an 
inverted input thereof to thereby output a radio frequency generating 
signal having the same zero level signal so that an accurate channel bit 
can be obtained by a zero-crossing. 
Also, the channel bit signal processor 109 includes a zero crosser for 
preventing the radio frequency generating signal RF selected from the 
playback signal selector 108 from being mixed with the record channel bit 
signal CHBw. 
As shown in FIG. 24, the zero crosser includes: a comparator 164 for 
comparing the radio frequency generating signal RF applied to an 
uninverted input thereof with the standard voltage Vref fed back to an 
inverted input thereof; a buffer 165 for receiving the output of the 
comparator 164 and generating a playback channel bit signal CHBr; a low 
pass filter 166 connected parallel to an output of the buffer 165 to 
thereby filter the output of the buffer 165; and a differential amplifier 
167 for zero-crossing the output of the low pass filter 166 applied to an 
inverted input thereof and generating a standard voltage Vref through the 
resistance R6 to an inverted input of the comparator 164. 
Here, the resistance R6 is provided between the inverted input of the 
comparator 164 and a ground voltage and connected parallel to a resistance 
R5. 
The low pass filter 166 includes: resistances R7, R8 serially connected to 
each other; a capacitor C1 connected parallel between an uninvested input 
of the differential amplifier 167 and the resistance R7; and a capacitor 
C2 connected parallel to a node between the resistance R7 and R8. 
The operation of the thusly composed zero crosser will be described. 
First, the radio frequency generating signal RF is applied to an uninverted 
input of the comparator 164 and compared with the standard voltage Vref 
applied to an inverted input of the comparator 164. The compared signal is 
buffered in the buffer 165 which in turn generates a square wave serving 
as a zero-crossed playback channel bit signal CHBr. 
The output of the buffer 165 is filtered in the low pass filter 166 and 
applied to an uninverted input of the differential amplifier 167, which 
generates the standard voltage Vref for being applied to an inverted input 
of the comparator 164 in accordance with a zero-crossing signal level set 
by a variable resistance Rv. At this time, the level ratio of a low and a 
high signal in the zero-crossed channel bit signals is set to be "1" to 
thereby compensate for an asymmetry of the disc, and to the standard 
voltage Vref of the comparator 164 there is added a voltage proportionate 
to a light amount which has detected a signal to thereby zero-cross the 
signal. 
The optical disc recording/playing apparatus as described above employs a 
light wave width modulating method, wherein data is recorded by changing 
the reflection degree of the optical disc to thereby record data, sensing 
the reflected light amount and detecting a playback signal, thereby 
recording/playing-back data on the disc. 
However, when playing back an optical magnetic disc reads data by detecting 
a polarizing amount of light reflected after being applied to the magnetic 
disc. This is because an information signal is recorded in accordance with 
a magnetic direction of a signal track and the polarizing direction of 
light which is operated with magnetic is changed in accordance with a 
magnetic direction. 
Therefore, the structure of an optical pick-up must be changed, a magnetic 
head is required, and the optical pick-up must be formed of a polarizing 
optical system. Also, in a recording method there are provided a magnetic 
modulating record method and an optical modulating record method. 
FIG. 25 shows the fifth embodiment of the optical disc recording/playing 
apparatus which employs an optical magnetic disc adapting a magnetic 
modulating record method, wherein the optical pick-up 205 of the fourth 
embodiment as shown in FIG. 20 is provided differently and instead of the 
signal shapers 203, 204 there are provided playback signal processors 206, 
207 for generating a radio frequency generating signal by processing the 
signal reproduced by the laser beam LB2. 
Also, there is provided a light stabilizer 208 instead of the light 
stabilizing modulator 121 and a magnetic head modulator 209 for recording 
in the optical magnetic disc 102 the channel bit signal CHBw output from 
the channel bit processing transfer unit 120 in accordance with 
controlling the magnetic direction of the magnetic head 210. 
As shown in FIG. 26, the photo detector PD1 has four photo detecting 
elements PD1A, PD1B, PD1C, PD1D partitioned track-wardly and radially 
relative to the disc, and above and below the photo detecting elements 
PD1A, PD1B, PD1C, PD1D there are provided photo detecting elements PD1I, 
PD1J. 
On the right side of each of the photo detectors PD1I, PD1J there are 
correspondingly provided photo detecting elements PD2I, PD2J, and on the 
left side of each of the photo detectors PD1I, PD1J there are 
correspondingly provided photo detecting elements PD3I, PD3J. 
The operation of the fifth embodiment of the optical disc recording/playing 
apparatus according to the present invention is formed similar nearly to 
the fourth embodiment so that only the different portions will be 
described. 
First, on a signal track of the optical magnetic disc having a land and 
groove structure there are converged the laser beams LB1, LB2, LB3 each 
spaced by a certain distance, and the light reflected from the disc record 
surface is detected in accordance with the three photo detectors PD1, PD2, 
PD3. 
The photo detecting-elements PD1A-PD1D, PD1I, PD1J of the photo detector 
PD1 detect the amount of the laser beam reflected from the laser beam LB1 
to thereby output electrical signals a,b,c,d,i1,j1, and the photo 
detecting elements PD2I, PD1J of the photo detector PD2 detect the amount 
of the laser beam reflected from the laser beam LB2 to thereby output 
electrical signals i2,j2, and also the photo detecting elements PD3I, PD3J 
of the photo detector PD3 detect the amount of the laser beam reflected 
from the laser beam LB3 to thereby output electrical signals i3,j3. 
The playback signal processor 103 outputs a radio frequency generating 
signal RF1 by subtracting j1 from i1 (i1-j1), a focus control signal Fe by 
(a+c)-(b+d), and a tracking control signal Te by (a+b)-(c+d). 
The playback signal processor 206 subtracts j2 from i2 (i2-j2) to thereby 
output a radio frequency generating signal RF2, and the playback signal 
processor 207 subtracts j3 from i3 (i3-j3) to thereby output a radio 
frequency generating signal RF3. 
Then, in accordance with the control of the microprocessor 107, the 
playback signal selector 108 selects one of the radio frequency generating 
signals RF1, RF2, RF3. 
When recording data, the light stabilizer 208 controls the laser diode LD 
with the strength of a record light in accordance with the control of the 
microprocessor 107 so that the record channel bit signal CHBw output from 
the channel bit processing transfer unit 120 is modulated in the magnetic 
head modulator 209 and recorded in the optical magnetic disc 101 through 
the magnetic head 210. The rest of the operation will be omitted which is 
identical to that of the fourth embodiment. 
The previously described present invention employs the three laser beams 
LB1, LB2, LB3 which are necessarily essential. That is, when playing-back, 
the laser beam LB1 is only used. When recording, the pair of laser beams 
LB1, LB2 are employed if applied to a blank disc, and the pair LB1, LB3 
are used if applied to a recorded disc. 
As shown in FIG. 27, when there are provided a pair of laser beams LBI1, 
LBI2, the beam spot LBI2 is placed behind the beam spot LBI1 to be spaced 
by a certain distance dL. Therefore, when recording on a blank disc, a 
signal is recorded by the beam LBI1 and read by the beam LBI2, and when 
recording on a recorded disc, a signal is read by the beam LBI1 and 
recorded by the beam LBI2, thereby requiring only a pair of laser diodes 
LD. 
As shown in FIG. 28, the sixth embodiment of the optical disc 
recording/playing apparatus according to the present invention which 
employs a pair of laser diodes LD is provided by differentiating the 
optical pick-up 211, the playback signal processor 212 and the playback 
signal selector 213, eliminating the light stabilizing modulator 121, and 
replacing the light stabilizers 122, 123 with light stabilizing modulators 
214, 215, respectively from the first embodiment of FIG. 6. 
The optical pick-up 211 includes: laser diodes LD1, LD2 for generating a 
laser beam by the control of the light stabilizing modulators 214, 215; a 
beam splitter BS for reflecting the beams LBI1, LBI2 generated by the 
laser diodes LD1, LD2; an object lens OL for converging the laser beams 
LBI1, LBI2 reflected from the beam splitter BS onto a portion of a signal 
track of the disc; a focus activator FA and a tracking activator TA for 
moving the object lens OL in the direction of tracking and/or focusing so 
that the object lens OL can accurately converge the laser beams LBI1, LBI2 
onto a signal track of the disc; a sensor lens SL for converging the beams 
which have passed through the beam splitter BS after being reflected from 
the disc; a photo detector PDI1 for converting the beam converged by the 
sensor lens SL to electrical signals a,b,c,d; and a photo detector PDI2 
for generating a radio frequency generating signal RF13. 
As shown in FIG. 29, the photo detector PD11 is partitioned in a track-ward 
and radial direction to form four photo detecting elements 
PDA,PDB,PDC,PDD, and the photo detector PD12 is composed of a single photo 
element. 
The playback signal processor 212 receives the electrical signals a,b,c,d 
output- from the photo detector PD11 and outputs a focus control signal Fe 
and a tracking control signal Te, and the radio frequency generating 
signal RF11 is applied to the record motor control signal detector 113. 
The playback signal selector 213 selectively outputs the radio frequency 
generating signal RF11 output from the playback signal processor 212 and 
the radio frequency generating signal RF12, in accordance with the control 
of the microcomputer 107. 
The operation of the thusly provided sixth embodiment of the present 
invention will be described. 
The sixth embodiment is provided to record/play-back data using the pair of 
laser beams LB11, LB12, wherein a signal is read by the beam LB11 when 
playing back, and when recording on a blank disc, a signal is recorded by 
the beam LB11 and read by the beam LB12, and also when recording on a 
recorded disc, a signal is read by the beam LB11 and recorded by the beam 
LB12. 
The photo detector PD11 outputs the electrical signals a,b,c,d detected in 
the photo detecting elements PDA,PDB,PDC,PDD to the playback signal 
processor 212 which in turn outputs a radio frequency generating signal 
RF11 by (a+b+c+d), a focus control signal Fe by (a+c)-(b+d), and a 
tracking control signal Te by (a+d)-(b+c). 
The photo detector PD12 outputs to the playback signal selector 213 the 
radio frequency generating signal RF12 detected by the laser beam LB12. 
The focus controller 104 carries out a focus control by operating the 
focus activator FA in the optical pick-up 211 in accordance with the focus 
control signal output from the playback signal processor 212. The tracking 
controller 105 performs a tracking control by operating the tracking 
controller TA in the optical pick-up in accordance with the tracking 
control signal Te of the playback signal processor 212. 
First, there will be explained a playing-back of a recorded signal. 
The light stabilizing modulator 214 stably maintains the laser beam LB11 
output from the laser diode LD11 to thereby carry out a read operation, 
and the laser diode LD12 is turned off in accordance with the control of 
the light stabilizing modulator 215. 
The beam LB11 reflected against the signal surface of the disc 101 is 
detected in the form of the electrical signals a,b,c,d in the photo 
detecting elements PDA,PDB,PDC,PDD of the photo detector PD11, and the 
laser beam LB12 is generated in the form of a radio frequency generating 
signal RF13 in accordance with the photo detector PD12. 
The playback signal processor 212 outputs a radio frequency generating 
signal RF11 by (a+b+c+d), a focus control signal Fe by (a+c)-(b+d), and a 
tracking control signal Te by (a+d)-(b+c) to thereby perform a focus 
control and a tracking control. 
The playback signal selector 213 selects the radio frequency generating 
signal RF11 in accordance with the control of the microcomputer 107, and 
the selected signal RF11 is applied to the channel bit signal processor 
109 and detected in the formed of a playback channel bit signal CHBr from 
which the playback channel bit synchronous signal SYNr and the playback 
clock signal CLKr are detected. 
At this time, the playback channel bit synchronous signal SYNr output from 
the channel bit signal processor 109 and the standard synchronous signal 
SYNs output from the standard clock generator 111 are applied to the 
playback motor control signal detector 112 which in turn generates a 
playback motor control signal Mr. The motor control signal selector 114 
receives the playback motor control signal Mr and outputs a motor control 
signal Me in accordance with the control of the microcomputer 107 to 
thereby control the spinning rate of the disc 101. 
The playback channel bit signal CHBr output from the channel bit signal 
processor 109 is modulated and error-corrected in the digital signal 
processor 110 which in turn generates a playback data. 
Next, a case recording data on the disc will be explained. 
The laser diode LD12 is controlled by a reading photo amount in accordance 
with the control of the light stabilizing modulator 215, and the radio 
frequency generating signal RF12 detected in the photo detector 106 is 
applied to the radio frequency signal detector 106 to detect a playback 
signal and outputs the detected signal to the microcomputer 107. At this 
time, if there is a radio frequency generating signal it is judged that 
the disc is previously recorded. 
Based on the judged resultant, the beam LB11 is applied to playing-back and 
the beam LB12 is applied to recording. Therefore, the light stabilizing 
modulator 215 adjusts the emitted light amount in the laser diode LD12 to 
a record mode in accordance with the control of the microcomputer 107, and 
the light stabilizing modulator 214 adjusts the emitted amount of the 
laser diode LD11 to a playback mode, thereby playing back the data 
recorded previously in the disc by the laser diode LD11 and the photo 
detector PD11 to result in detecting the radio frequency generating signal 
RF11. 
The playback signal selector 213 selects the radio frequency generating 
signal RF11 in accordance with the control of the microcomputer 107, and 
the channel bit signal processor 109 detects from selected signal RF11 a 
playback channel bit signal CHBr, the playback channel bit synchronous 
signal SYNr and the playback clock signal CLKr. 
The record clock selector 118 obtains a record clock signal CLKw by 
selecting a playback channel bit clock signal CLKr output from the channel 
bit signal processor 109, in accordance with the control of the 
microcomputer 107. 
The synchronous delay unit 117 delays the playback channel bit synchronous 
signal SYNr output from the channel bit signal processor 109 to thereby 
output a delayed synchronous signal SYNrd. 
The channel bit processing transfer unit 120 processes the output of the 
record digital signal processor 111 by an appropriate format, outputs the 
record channel bit signal CHBw to the light stabilizing modulator 123 in 
accordance with the record clock signal CLKw and controls the emitted 
light amount of the laser diode LD12 to thereby record a signal on the 
track of the disc 101. 
The playback channel bit synchronous signal SYNr output from the channel 
bit signal processor 109 and the standard synchronous signal SYNs output 
from the standard clock generator 111 are applied to the playback motor 
control signal detector 112 which in turn generates a playback motor 
control signal Mr. The motor control signal selector 114 receives the 
playback motor control signal Mr and outputs a motor control signal Me in 
accordance with the control of the microcomputer 107 to thereby control 
the spinning rate of the disc 101. 
Then, the case of a blank disc will be explained, in which case a radio 
frequency generating signal RF12 detected by the radio frequency signal 
detector 106 does not exist. when recording in a blank disc, the laser 
beam LB11 is used for recording and the beam LB12 is employed for playing 
back, so that the light stabilizing modulator 214 adjusts the emitted 
light amount of the laser diode LD11 to a record mode, and the light 
stabilizing modulator 215 adjusts the emitted light amount of the laser 
diode LD11 to a playback mode, in accordance with the control of the 
microcomputer 107. 
Also, by the laser diode LD12 and the photo detector PD, the data recorded 
previously on the disc is played back so that the radio frequency 
generating signal RF12 is detected. 
The playback signal selector 213 selects the radio frequency generating 
signal RF12 in accordance with the control of the microcomputer 107, and 
the channel bit signal processor 109 detects from selected signal RF12 a 
playback channel bit signal CHBr, the playback channel bit synchronous 
signal SYNr and the playback clock signal CLKr. 
The record motor control signal detector 113 outputs a record motor control 
signal Ms by receiving the playback channel bit signal CHBr and the 
playback channel bit clock signal CLKr each output from the channel bit 
signal processor 109, a radio frequency generating signal RF11 output from 
the playback signal processor 212, and the record clock selector 118 
receives the record motor control signal Ms and outputs the motor control 
signal Me in accordance with the control of the microcomputer 107 to 
thereby control the spinning rate of the disc 101. 
The standard clock CLKs output from the standard clock generator 111 is 
applied to the record clock selector 118 and used as a record clock signal 
CLKw. 
Accordingly, an information signal is recorded by the laser beam LB11, 
delayed for a certain time and recorded in the form of a radio frequency 
generating signal RF11 reproduced by the laser beam LB12, thereby enabling 
a constant rate in recording data. 
The channel bit processing transfer unit 120 processes the output of the 
record digital signal processor 111 by an appropriate format, outputs the 
record channel bit signal CHBw to the light stabilizing modulator 214 in 
accordance with the record clock signal CLKw and controls the emitted 
light amount of the laser diode LD11 to thereby record a signal on the 
track of the disc 101. 
With reference to FIG. 30, there will be described an operation of the 
microcomputer 107 to carry out the above operational steps. 
First, when playing back a signal recorded in the disc 101 (38), the 
microcomputer 107 controls the light stabilizing modulator 214 so as to 
turn the laser diode LD11 to a light amount suitable to a read mode, and 
turns off the laser diode LD12 by controlling the light stabilizing 
modulator 215. 
Then, by controlling the playback signal selector 108 there is selected a 
radio frequency generating signal RF11 output from the photo detector 
PD11, by controlling the motor control signal selector 114 the playback 
motor control signal Mr output from the playback motor control signal 
detector 112 is selected in the form of a motor control signal Me to 
thereby control motor 116. (39) 
Next, the playback channel bit signal CHBr output from the channel bit 
signal processor 109 is modulated and error-corrected in the digital 
signal processor 110 and then generated in the form of a playback data to 
read a data recorded in the disc to thereby complete the playback 
operation. (40), (41) 
Meanwhile, when recording a data in the optical disc 101, the laser diode 
LD12 is controlled to have an appropriate light amount at a read mode by 
controlling the light stabilizing modulator 215 and detects whether there 
is a detected radio frequency generating signal so as to judge whether it 
is a second recording on a recorded disc or an initial recording on a 
black disc. (42) 
When there is no detected radio frequency generating signal, that is, it is 
judged as an initial recording, the is microcomputer 107 controls the 
light stabilizing modulator 214 to thereby adjust the laser diode LD11 
suitable to a light amount in a read mode, and by controlling the light 
stabilizing modulator 215 the laser diode LD12 is controlled to have a 
light amount at a read mode. 
Then, the radio frequency generating signal RF12 is selected from the 
playback signal selector 108, the record motor control signal Ms is 
selected from the motor control signal selector 114 in accordance with a 
motor control signal Me, and in accordance with the record clock signal 
CLKw the standard clock signal CLKs is selected. (44) 
Therefore, by controlling the channel bit processing transfer unit 120 a 
record data is processed in an appropriate format, the record channel bit 
signal CHBw is applied to the light stabilizing modulator 122 in 
accordance with the record clock signal CLKw so as to control the emitted 
light amount of the laser diode LD11, thereby completing the record 
operation. (45), (46) 
When recording a data in a previously recorded disc, the microcomputer 107 
controls the light stabilizing modulator 214 to adjust the laser diode 
LD11 to have a light amount at a read mode, and by controlling the light 
stabilizing modulator 215 the laser diode LD12 is controlled to have a 
light amount at a read mode. 
Then, the radio frequency generating signal RF11 is selected from the 
playback signal selector 108, the record motor control signal Mr is 
selected from the motor control signal selector 114 in accordance with a 
motor control signal Me, and in accordance with the record clock signal 
CLKr the standard clock signal CLKs is selected. (47) 
Therefore, by controlling the channel bit processing transfer unit 120 a 
record data is processed in an appropriate format, the record channel bit 
signal CHBw is applied to the light stabilizing modulator 215 in 
accordance with the record clock signal CLKw so as to control the emitted 
light amount of the laser diode LD12, thereby completing the record 
operation. (48), (49) 
As described above, the present invention provides an unwobbled optical 
disc which is not recorded by a pilot signal serving as a free-formatted 
auxiliary signal for detecting a disc spinning rate and an address signal 
for detecting the location of a signal track to carry out a 
record/playback operation by placing laser beam spots spaced by a certain 
distance on the signal track of the disc, thereby easily being applicable 
to a large scaled optical disc driver and enhancing compatibility of the 
optical disc.