JP3203618B2 - Optical disk record carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writable optical
Regarding the disk recording medium, the recorded disk is
Compact Disc), CD-ROM, CD-I (Dialogue)
CD), CDV (CD with video), LV (Laser
Optical data standardized for playback only, such as
Disk (in this application, this is called a “read-only optical disk”).
U. ) So that it can be used as a playback device.
It does not require a reproducing device for use. [0002] 2. Description of the Related Art Conventionally, as a writable optical disk, D
RAW (write-once type), E-DRAW (erasable type) disk
Was there. DRAW disc can be written only once
, For example, metal generated by heat generated by laser beam irradiation
In some cases, information pits are formed by burning off the recording film. [0003] E-DRAW discs are rewritable
And those that use magneto-optical recording,
Some use the phase change between the morphus state
You. [0004] SUMMARY OF THE INVENTION The above conventional DRAW data
Discs and E-DRAW discs are read-only optical discs.
(CD, CD-ROM, CD-I, CDV, LV, etc.)
And recording format, disk shape (outer diameter, etc.), rotation speed
The playback device of these read-only optical disks
Could not be regenerated on the device. In addition, the recording format and the disk shape
Even if it is the same as a read-only optical disk, magneto-optical or optical
In the case of using the phase change, the light reflectance is low (the mirror
(For example, the emissivity is 50% or less).
I couldn't live. [0006] Further, the metal film is burned by the conventional laser beam irradiation.
If the information pit is formed by cutting, the reflectance is sufficient.
However, a powerful gas laser is required for recording,
Recording equipment becomes large and expensive, and is used as consumer equipment
I couldn't do that. [0007] The present invention has the above problems in the prior art.
The point is solved and the reproduction device of the reproduction only disk is used for reproduction.
And a small and inexpensive recording device.
To provide an optical disk recording medium that can be
Things. [0008] SUMMARY OF THE INVENTION The present invention provides a semiconductor laser.
It is a material that can be recorded with theMirror sectionReflectivity 59-75
% Of the recording material is formed on the recording surface.
20 nm to 50 nm depth on the side where the light is incident
To form a pre-groove and adjust the mechanical dimensions
Playback of read-only optical discs in accordance with the disc's standard dimensions
It is characterized by being recorded so that it can be reproduced on the device.
It is. [0009] [0010] According to the optical disk record carrier of the present invention,
Playback is also performed as a playback device for read-only optical discs
Can be. [0012] DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
I do. FIG. 1 shows an optical disk recording carrier of the present invention.
It shows the outline of the whole system that plays from the recording.
is there. The optical disk 1 (optical disk recording carrier)
A material that can be recorded with a semiconductor laser and has a relatively high light reflectance
The recording surface is composed of the material and the mechanical dimensions are
3 playback-only optical disc (CD, CD-RO
M, CD-I, CDV, LV, etc.)
With a shallower pre-groove.
You. The recording device 2 reproduces an input signal to be recorded.
Standard format of read-only optical disk played by device 3
As the data signal of the mark length recording method that matches the
Output at a constant transfer speed, and
At the standard speed (for CLV discs, the standard linear speed and data
At a predetermined rotation speed determined from the transfer speed of the
Drives the optical disk 1 (at the standard rotation speed in the case of a V disk)
And the standard track track of the read-only optical disc.
Formed on the optical disc 1 in advance so that
The optical disk 1 and the semiconductor laser are
The position of the semiconductor laser according to the data signal.
The recording surface of the optical disc 1 by controlling the irradiation state of the laser
To form pits, and recording on the optical disc 1 is performed. The optical disk 1 recorded by the recording device 2 is
CD, CD-ROM, CD-I, CDV, L
V using a playback device for read-only optical discs such as V
It is. Incidentally, any read-only optical disk system
Whether to apply the system depends on the type of input data to be recorded.
Can be determined. For example, for audio data
Can use a CD system. In this case, light
Use a disc that conforms to the CD standard dimensions as disc 1.
As the recording device 2, the CD standard format and
Use the one that records data on optical disc 1 at rated line speed
And a CD player or a CD player as the playback device 3.
Player that can be used as both a player and an LV player.
You. Similarly, in the case of image + audio data,
LV system, CDV system, computer data
In the case of CD-ROM system, computer data,
Digital data such as audio data and still image data
Input data to be recorded such as a CD-I system
Type of read-only optical disk system used according to type
Classes can be defined. Next, a specific example of the system shown in FIG. 1 will be described.
I do. Here, C is used as a read-only optical disk system.
Can be played on existing CD players using the D system
To record on the optical disk record carrier of the present invention
Will be described. Here, the conditions of the record carrier means are shown in Table 1.
Determined as follows. [0019] [Table 1] FIG. 2 shows an embodiment of the optical disk recording carrier. Optical disc
K1 is transparent such as polycarbonate or acrylic (PMMA)
Alloy of In, Bi, Sn, etc. on the surface of the disk substrate 10
(For example, In-An-Ges alloy) or TeC alloy
A thin film 12 having a thickness of several tens nm is formed, and
It is used in the format. The substrate 10 and the thin film 12 have a pre-groove
(Guide groove) 16 'is formed, and the pre-groove 16'
The upper thin film 12 is burned out by laser light to make a hole,
These holes serve as pits 18 for recording information.Leh
On the side where the light is incidentPregroove 16 'depth
Is set to 20 to 50 nm. Also, pre-groove
The width is set to 0.3 μm to 1.3 μm. As shown in FIG. 2, pits are formed in the pregroove 16 '.
When recording 18, use the tracking error detection method.
Any of the three-beam method and the push-pull method can be used.
The pits 18 are recorded on the lands 17 as shown in FIG.
In this case, the push-pull method cannot be used and the three-beam method cannot be used.
Used. As described above, the surface thin film of the disk substrate 10
12 is an alloy of In, Bi, Sn, etc. (for example, In-An-
Ges alloy), TeC alloy, etc.
(Plane) part reflectivity can be increased to 59-75%
Then, the data can be reproduced by a reproducing apparatus such as an existing CD. FIG. 4 shows the mirror reflectivity and the existing CD format.
Layer compatibility (100% for all CD players)
And playback power).
It shows the person in charge. Pre-groove 16 'depth
When the thickness is set to 20 to 50 nm as in the embodiment,
Reflectivity of more than 59% and compatibility of about 100%
Become. On the other hand, as in the conventional case, the pre-groove 16 '
When the depth is large (for example, 75 nm), the mirror reflectance is
Compatibility will be 100% unless it is 75% or more
Absent. The reason will be briefly described. Mi here
Is the reflectance of the part without the pre-groove.
Yes, originally, if a pre-groove is provided, it will only reflect
The rate drops to some extent. The shallower the pre-groove
The rate of decrease in reflectance is small, resulting in compatibility
It goes up. Also, increase the reflectivity of the mirror.
When a metal film such as Al is formed on the
Need high laser power to break 12 and record
And the mirror reflectivity is set to 75% or more as in the related art.
Requires a powerful gas laser or the like. In contrast,
Selection of material and pregroove 16 'as in the embodiment of FIG.
25-35nm shallower mirror reflection
When the rate is 59-75%, relatively low laser light power
Recording becomes possible, and about 100% compatibility
And recording with a semiconductor laser becomes possible.
It is possible to configure the recording device in a compact and inexpensive manner. FIG. 5 shows a specific example of the recording apparatus 2 shown in FIG.
The optical disk 1 is configured to have mechanical dimensions suitable for a CD.
I have. The disk servo circuit 26 has a system control
Disk motor 22 at the linear velocity
Control at a constant. This constant linear velocity control is performed by the optical head 23.
Is performed by arithmetic control based on the position of. Focus servo and tracking server
The circuit 28 responds to a command from the system controller 29.
From the semiconductor laser in the optical head 23.
Controls focus and tracking of laser light. G
Racking control is performed on the pre-glue formed on the optical disc 1.
This is performed by detecting a loop. Feed servo times
The path 27 is controlled by a command from the system controller 29.
Drive the feed motor 30 to drive the optical head 23
1 in the radial direction. An input signal to be recorded on the optical disc 1 is
In the case of a digital signal, it is directly input to the data signal forming circuit 32.
In the case of an analog signal, the data is passed through an A / D converter 34.
Is input to the data signal forming circuit 32. Of this input data
Sampling frequency and number of data bits are CD data
It is said that it conformed to. Data signal forming circuit 32
Interleaves the input data to check for errors.
Code, form subcodes, and perform EFM modulation.
In a format and transfer rate suitable for CD
To form and output serial data. This data is stored in the drive interface
25, the data signal correction circuit 36 performs predetermined correction.
And input to the laser generation circuit 35. Laser generation circuit
Reference numeral 35 denotes a semiconductor laser in the optical head 23 according to the data signal.
Drive the laser to irradiate the recording surface of the optical disc 1 with laser light
And record. Thus, the optical disc 1 has a CD
Format, transfer speed and linear speed (1.
(2 to 1.4 m / s). Next, the data signal correction circuit 36
Data signal correction will be described. Data signal correction circuit 36
Means that the data signal is
The waveform is corrected according to the corresponding length. That is, light
The data due to the laser light thermal accumulation effect on the recording surface of the disc 1
Data signal timing and the position of recording pits and blanks
Misalignment can be achieved by increasing or decreasing the data signal timing.
Data of the recorded pit width
This is prevented by dividing the signal timing. Ingredient
Physically, the increase or decrease in data signal timing
When forming a pit having a short blank length, the laser
Shorter light irradiation time and longer blank length immediately before
When forming pits, start irradiation of the laser light earlier.
Laser light when forming long pits
The firing time is shortened. Also, data signal timing
The pit width is between 0.3 and 0.9 μm
The number of divisions to be formed, the pulse of each division laser light pulse
The pulse width and pulse intensity are determined. Hereinafter, these correction controls will be described in detail.
I will tell. <Regarding increase / decrease control of data signal timing>
The recording method is based on the pit length to be formed as shown in FIG.
(For example, 231n per 1T for CD)
s) Irradiation with laser light or as shown in FIG.
Time from a time corresponding to the pit length to be formed
Interval t₀Laser light for the time subtracted
Was. The pit length or blank length is recorded data.
Length varies depending on the number of consecutive "1" or "0"
(In case of CD format, 3-11
T), the formed pit length is the blank length immediately before (hereinafter
Below, it is called "just before blank length". ). You
In other words, the shorter the blank length immediately before, the earlier the pit is shaped.
The heat generated during the formation of the next pit affects the melting.
Even if the laser beam irradiation time is the same,
The shorter the blank length, the longer the pits are formed. FIG. 7 shows that the pit length to be formed is blank immediately before.
The change in length depending on the length
It is shown about the pit (the same length as the pit length)
Based on the combination of the immediately preceding blank length, the reference Ref
, Respectively. ), From this figure
As shown, the shorter the previous blank length, the earlier the blank
Is easily melted under the influence of heat when forming
Therefore, even if the irradiation time is the same, the pit length is long
I have. For this reason, the reproduced signal contains much jitter and error
Or a reproduced signal with a poor S / N ratio. When the immediately preceding blank length changes, the pitch
Not only the irradiation length but also the irradiation start position
There is also a change in the relationship with the starting position of the pit. Sand
In other words, the longer the blank length immediately before, the
The distance to the starting point of the kit becomes longer. This is the last blank
The longer the length, the less the heat from the pit immediately before
This is because the recording film disappears and the recording film hardly melts. Therefore, regardless of the immediately preceding blank length,
If the firing start position is fixed, the longer the blank length immediately before
The starting position of the pit is shifted backward, and the blank length is correct.
Can not be obtained. The pit length also varies as recorded data.
Since the rank length has exactly the same data weight,
In that case, the reproduced signal still contains jitter.
U. When pits are formed on a disk,
The longer the pit length, the longer the irradiation time of the laser beam
As the recording film becomes longer, the heating of the recording film becomes
Easier to do. For this reason, FIG. 6A or FIG.
Like the pit length, regardless of the pit length.
If the laser beam is irradiated for the same
If the lengths are the same, for example, the pit length of 3T pit
Even if the laser power is adjusted so that
Actually formed as the pit length to be recorded on the disk becomes longer
The pits that are made will be longer than the specified value. Re-
Looking at the raw waveform eye pattern, for example, each of 3 to 11T
Reproduction with 3T blanks formed immediately after the pits
The eye pattern of the waveform is as shown in FIG.
Becomes longer, the amplitude of the 3T blank becomes smaller. One
In other words, the longer the pit length, the longer the specified pit length
It becomes. Therefore, the laser light irradiation time itself also causes jitter.
Was the cause. Therefore, the data signal correction circuit 36
When forming a pit with a short blank length, the laser beam
The irradiation time is shortened. That is,
Irradiation time for a pit with a short blank length just before
The pit length tends to be longer,
Laser light when forming a pit with a short blank length immediately before
Is formed longer by shortening the irradiation time of
The tendency is negated and a pit length close to the specified value is formed.
Can be. As a result, a reproduced signal with less jitter can be obtained.
With less error or good S / N
A raw signal is obtained. As described above, the blank length immediately before is long.
The pit start end position shifts backward from the irradiation start position
Therefore, the data signal correction circuit 36
Irradiation of laser beam when forming pits with long rank length
Set the start position of the pit to the correct position so that
So that a blank length close to the specified value can be obtained.
are doing. Further, as described above, the pit has a pit length.
The longer the length, the longer the irradiation time
During irradiation when forming long pits
Shorten the interval, counteract the tendency to form longer,
A pit length closer to the specified value can be formed
I have to. The irradiation time by the data signal correction circuit 36 and the
And a specific example of correction control of irradiation start timing
I will tell. (1) Correction of irradiation time by last blank length As described above, the shorter the blank length immediately before, the shorter the irradiation time.
Because the pit length tends to be longer,
As shown in FIG. 0, the shorter the immediately preceding blank length, the shorter the irradiation time.
In short, counteract this trend. Pit length to be formed
Before NT when N is constant NT (N is 3, 4 ... 11)
Table 2 shows an example of the irradiation time for each blank length. [0041] [Table 2]Where T₀= 1 / 4.3218 MHz t = 0 to 500 ns β3, N> β4, N> β5, N>…> β11, N The optimum values of t and βn, N in Table 2 are obtained by experiments.
The peak value close to the specified value regardless of the length of the previous blank length.
Cut length can be formed. As a result, the playback signal
Jitter is reduced, errors are reduced or S / N is reduced
It will be good. (2) The irradiation start tie by the immediately preceding blank length
Correction of mining As described above, the irradiation start position becomes longer as the immediately preceding blank length becomes longer.
In contrast, the starting position of the pit tends to shift backward. This
The irradiation start position regardless of the blank length immediately before
The irradiation time by the blank length immediately before (1).
The correction is performed after the irradiation period as shown in FIG.
(Ie, add the correction to the back)
The pit length can be obtained correctly, but the pit position is not
(The longer the previous blank length is, the more it shifts backward.
Is almost proportional to the immediately preceding blank length. ), Blanc
The cut length cannot be obtained correctly. As recorded data,
G and blank lengths have exactly the same data weight
As a result, this still includes errors in the reproduced signal.
I will. Therefore, here, the illumination by the immediately preceding blank length is used.
The correction of the irradiation time is performed as shown in FIG.
Do it on the front side (ie add the correction to the front side)
To As a result, pits are formed at regular positions.
Therefore, the blank length can be obtained correctly. (3) Irradiation time depending on pit length to be formed
Correction As described above, the longer the pit, the longer the pit length with respect to the irradiation time.
Tend to be formed longer, as shown in FIG.
The longer the pit, the shorter the irradiation time
Try to negate. The blank length just before was fixed at 3T
Table 3 shows an example of the irradiation time for each pit length in the case. [0045] [Table 3] Where T₀= 1 / 4.3218 MHz t = 0 to 500 ns α_n= 0 to 100 ns (N = 4, 5, ..., 11) α_Four<Α_Five<…… <α₁₁ T and α in Table 3_nBy experimentally finding the optimal value of
The pit length close to the specified value regardless of the length of the pit length
Can be formed. At that time, the eye putter of FIG.
As shown in the figure, the 3T brand after the 3-11T pit
The amplitude of the peak is almost constant. As a result, the recording power
The relative ratio of the jitter is as shown in FIG.
It is reduced compared to the shooting method. Also, the recording power
As shown in FIG. 14, the relative ratio of the error occurrence rate to
It is reduced as compared with the conventional irradiation method. (4) Pit length to be formed and blank immediately before
Of irradiation time and irradiation start timing by combination of length
correction As described above, the pit length to be formed is
Because it is affected by rank length, depending on the combination
If the correction value is determined, a pit length closer to the specified value will be formed.
Can be Various pairs of pit length and blank length just before
Table 4 shows an example of the irradiation time by the combination. [0047] [Table 4]Where T₀= 1 / 4.3218 MHz t = 0 to 500 ns r_{m, n}= 0 to 100 ns (M: immediately preceding blank length, n: pit length, m, n = 3
4, ..., 11) For the same pit length n, γ_{3, n}> Γ_{4, n}>…> Γ_{11, n} For the same immediately preceding blank length m, γ_{m, 3}<Γ_{m, 4}<… <Γ_{m, 11} 3T-3T (last blank length 3T, pit length 3T)
Shooting time 3T₀− (T + γ_3,3) To T_Three, 7T-7T
Irradiation time 7T₀− (T + γ_7,7) To T₇, 11T-1
1T irradiation time 11T₀− (T + γ_11,11) To T₁₁When
In this case, the irradiation time was determined according to the immediately preceding blank length in Table 5.
The deviation of the pit length center position is
As shown in FIG. According to this, shown in FIG.
Compared to the case where the irradiation time is not corrected by the immediately preceding blank length
The deviation of the pit length became small. [0048] [Table 5] In this case as well, the correction amount of the irradiation time by the immediately preceding blank length
Is performed on the front side of the irradiation time (that is, the correction amount is
Pits) to form pits at regular positions
Therefore, the blank length can be obtained correctly. In the above embodiment, the irradiation power is fixed.
Was explained, but the pit length to be formed and
To change the irradiation power depending on the blank length immediately before
(The longer the pit length to be formed,
The irradiation power is reduced as the claw length becomes shorter. )
You can also. <Division control of data signal timing>
Laser beam on the disk for a time corresponding to the pit length
In the case of recording by irradiating the target, as shown in FIG.
The formed pit 40 has a small amount of melting at the leading edge 40a.
In addition, the closer to the trailing edge 40b, the greater the amount of melting,
Drops. This is for continuous irradiation of laser light.
Therefore, the recording portion of the disc is gradually heated, and the trailing edge 4
This is because 0b is more easily melted. For this reason, the trailing edge 40b of the pit is
As shown by the dotted line 40b ', the pit trailing edge 4
The position of 0b 'was sometimes incorrect. Also this
To reduce the intensity of the laser light,
As shown in FIG. 17, the pit leading edge portion 40a is insufficiently melted.
The position of the pit leading edge 40a may be incorrect
there were. Therefore, the disk recorded in this manner is
Disk or disc made from the master recorded in this way.
When the signal is played back, the playback signal becomes jitter (error in the time axis direction).
Difference) and low quality such as S / N deterioration
Had become. The pit length is “1” of the recording data or
Can take various lengths depending on the number of consecutive "0"
Is (3T-11T for CD format), pit length
As the length of the disk becomes longer,
The degree of heating becomes remarkable, and as shown in FIG.
Becomes wider. Therefore, the longer the pit length, the more jitter
Was getting worse. Also, because the pit width is wider,
When the disc reflectivity decreases, tracking and
Load on the focus servo circuit (increase the gain
There is a need to. ) And increase the recording density
could not. Therefore, in the data signal correction circuit 36,
In addition to increasing / decreasing the data signal timing, the signal
Splits the laser beam into multiple pulses within a time corresponding to the length of the laser
Control of data signal timing to irradiate
I do. As described above, the laser beam is divided and irradiated.
Even if the pit length is long, the heating of the optical disc 1 is intermittent
And it is difficult to accumulate.
As the disk recording film becomes hot, the trailing edge of the pit
It will not be melted excessively. So after the pit
The position of the edge is accurate. Also, the trailing edge of the pit is excessive
Increase the power of the laser beam as it will not be melted
This makes the position of the pit leading edge accurate.
Therefore, the positions of both the leading edge and the trailing edge of the pit can be accurately determined.
To reduce the jitter of the reproduced signal,
/ N can improve the quality of the reproduced signal
You. Further, the laser beam is applied to the disk recording film.
Heat does not easily accumulate, so regardless of the pit length,
The cut width can be made almost constant and narrow. But
Reflectivity increases, and tracking and
The burden on the cas servo circuit is reduced.
Can be ) And increase the recording density
Wear. The division number of the laser beam depends on the pit length.
(The longer the pit length, the greater the number of divisions
Make ), Always the best pit shape regardless of pit length
Shape can be obtained. The leading pulse width of the divided laser beam
To be wider than subsequent ones, and power to
To improve the melting of the pit leading edge.
Better, which further reduces jitter.
Can be made. Formed by data signal correction circuit 36
FIG. 19B shows an example of a divided pulse of the writing laser light.
Show. FIG. 19A shows a conventional continuous laser corresponding thereto.
Light. FIG. 19C shows a case where the laser beam is formed by the divided laser beam.
3 shows the shape of the pit 50. The split laser beam is applied to the pit length to be formed.
The dotted line in FIG. 19C is divided into three within the same time.
51, 52 and 53 individually irradiate each pulse P1 to P3
These pits are formed when
By continuously irradiating P1 to P3, each pit 5
1, 52, 53 are connected to form a continuous pit 50
Is done. According to this, the laser beam is divided and irradiated.
Therefore, heat accumulation is small, and compared with the conventional continuous irradiation
Therefore, the width of the pit 50 at the rear edge 50b is small.
Therefore, the width of the pit 50 can be made almost constant with a narrow width.
As a result, the reflectance increases and the load on the servo circuit is reduced.
And the recording density can be increased. Also, the rear edge 50b does not melt too much.
Thus, the position of the trailing edge 50b is accurately defined. Also after
Since the edge 50b is not melted too much, the power of the laser beam is reduced.
The pit leading edge 50a
It becomes easy to melt, and the position of the pit leading edge 50a is accurately
Stipulated. Therefore, the jitter is reduced and the S / N is reduced.
It is possible to improve the quality of the reproduced signal such as improvement. By the way, the shape of the pit 50 is
Pulse width T of the light, duty ratio Ton / T, laser light
It changes according to power and the like. Therefore, due to heat accumulation
The pit width is small and the leading edge 5 of the pit 50
0a and the position of the trailing edge 50b are precisely defined, and
Adjust these values so that the pit 50 is not cut off halfway.
You. If the pulse width T becomes too long, one pulse
The width of the formed pit itself widens at the trailing edge,
The pit length to be formed.
The number of divisions so that the pulse widths are almost equal.
Preferably. The duty ratio Ton / T is large.
If the pulse width is too high (increase the pulse width),
The pit width is widened and reduced (narrowing the pulse width)
If it passes, the pit 50 will be cut off on the way.
Adjust the value so that the width is not too wide and
Adjust. The melting state also changes with the laser beam power.
Therefore, the laser beam power is adjusted at the same time. To experiment
According to the conventional laser, the laser irradiation is about 1.5 times
Preferable results were obtained when the optical power was changed. The CD format using the above pulse division
Example of the case where pits are formed on the optical disc 1
explain about. For a DRAW disc in CD format,
9 types of 3-11T (1T = 1 / 4.3218 MHz)
Data is recorded by a combination of pits having a length. Each head
Of setting the split laser beam for forming the pit
6 is shown. [0065] [Table 6] Note that T_1on,T_2on,T_3onAre the pulses P1 and P
2, the rise time width of P3, T_1off,T_2offAre each
This is the fall time width between the lus P1, P2, and P3. In the above setting example, 3-5T is divided into one, 6
8T is divided into two, and 9-11T is divided into three. What
The pit length 5T is 2 pulses, T_1on= 300-
800 ns, T_1off= 200-600 ns, T_2on= 100
It may be up to 400 ns. Formed by this split laser beam
FIG. 20C shows the pit shape to be formed. Laser light
Since the irradiation is split, the heat accumulation is small and the pit length is small.
Even if it becomes longer, the pit width is defined to be narrow and constant. Ma
In addition, the positions of the leading edge and the trailing edge of the pit are accurately defined. Using this divided laser beam, the DRAW display
Recorded on the disc, the jitter of the reproduced signal
As shown in FIG. 21, recording was performed using a conventional continuous laser beam.
The error was reduced by about 60% as compared with the case where the error occurred.
In FIG. 21, the vertical axis represents the reproduction signal for the recording signal.
The standard deviation of the time axis fluctuation of the signal
Duty of raw signal, that is, pit equivalent in the same signal
It shows how much the department occupies.
As shown in FIG. 22, the reflectance after recording is the
Approximately 10% increase compared to recording with continuous laser light
And the load on the servo circuit has been reduced. Note that, in FIG.
The axis is used for recording with continuous laser light and for playback duty.
Is 50%, but the relative ratio is 1 with the reflectance being 1.
ing. In the above example, the divided pulse is
And the subsequent pulse were not particularly distinguished (FIG. 19)
(See FIG. 23B), and as shown in FIG.
Increase the pulse width (about 1.1 to 2 times P2 and P3)
Degree), and as shown in FIG.
To raise (about 1.05 to 1.43 times of P2 and P3)
Degree), the pit leading edge can be more reliably melted.
And jitter is further improved. Also,
This allows subsequent pulses to reduce power,
Finer pits can be formed, the reflectivity increases,
The load on the servo circuit is further reduced, and
The degree can be increased. Widen the first pulse width
Table 7 shows a setting example in the case of the above. [0069] [Table 7]Error for recording power in case of setting condition of Table 7
FIG. 25 shows the relative ratios of the incidence rates. According to this,
Errors are reduced compared to continuous irradiation, and recording power is reduced.
-You can see that the margin goes up. In the above example, the laser light is completely separated.
The case where the power is divided by 0 (the power is 0 at the falling edge of the pulse)
However, as shown in FIG.
It can also be split. In the above example, the longer the pit length is,
Although the number of divisions was increased, the time corresponding to the length of the signal pit
The laser beam is divided immediately before the end of the period to be irradiated.
It is also possible to apply as two pulses.
In this way, the power of the laser light should be
Immediately before the end of the period, it can be lowered once. I
Therefore, heat accumulation due to the forward pulse is cut off at that point
Pits, regardless of the length of the pit,
Position of the pit trailing edge
Can be defined almost exactly by the backward pulse.
Therefore, the jitter is reduced and the reproduction signal such as the improvement of S / N is improved.
The quality of the issue can be improved. And the pit length
Regardless, the laser is emitted only immediately before the end of the period to be irradiated with laser light.
The pit length because it is only necessary to lower the optical power once.
Simplifies the circuit configuration compared to the case where the number is divided according to the number
be able to. FIG. 27 shows the recording pit width, jitter, and track.
The relationship between the amplitude of the error signal (three beam method) and the reflectance
However, the width of the recording pit is 0.3-0.9μ.
m, small jitter and large tracking error amplitude
The gain of racking control is large) and the reflectance is large. pit
When the width is 0.9 μm or more, adjacent track pits are
The possibility of reading increases, and the pit width is 0.3μm or less.
Is in a state in which pits are not effectively formed substantially,
In any case, jitter and the like deteriorate. The data signal correction circuit
According to No. 36, the recording pit width is in the range of 0.3-0.
Recording at 9 μm is easy. In the above example, the laser beam is completely separated.
The case of splitting has been described, but as shown in FIG.
It can also be divided to include a stream component. FIG.
As shown in FIG. 9, the power of the rising portion of the forward pulse P1
The pit leading edge more reliably.
And jitter can be further improved.
Wear. Also, after turning on the semiconductor laser,
It takes time for the light to reach steady state,
When the length is longer, the pitch from the position where the semiconductor laser is turned on is
The length to the position where the leading edge is formed tends to increase.
You. Therefore, a weak current is applied to the semiconductor laser even in the blank part.
The rise of the laser beam when it is turned on.
The pit leading edge is precisely defined, reducing jitter.
Can be further reduced. It should be noted that data signal timing increase / decrease control and
When using data signal timing division control together,
Pit length and immediately preceding blank
The effect of the data length is reduced,
The increase / decrease control can be smaller than in the previous example.
Wear. In the above embodiment, the present invention is applied to a CD system.
The case where the present invention is applied to a CD-ROM, C
Read-only disk system for DI, CD-V, LV, etc.
Also applicable to In addition, the recording device is configured as a
It can also be done. Also, only the linear velocity constant type disk system
Not only for fixed speed disk systems
You. Also, in the above embodiment, the present invention
Although the case where the present invention is applied to a
It can also be applied to discs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an outline of an entire system for performing recording to reproduction using an optical disk record carrier of the present invention. FIG. 2 is a diagram showing a specific example of the optical disc 1 of FIG. FIG. 3 is an enlarged view of a disk recording surface in the case of land recording. FIG. 4 is a characteristic diagram of a mirror reflectivity, compatibility with an existing CD player, and a laser beam power required for recording. FIG. 5 is a block diagram showing one embodiment of the recording apparatus of FIG. 1; FIG. 6 is a diagram showing an example of a conventional recording laser beam. FIG. 7 is a diagram showing a pit length shift when the irradiation time is not corrected according to the immediately preceding blank length. FIG. 8 is a diagram showing pit lengths formed by the laser light of FIG. 6; 9 is a diagram showing an eye pattern of a reproduced signal of a pit formed by the laser beam of FIG. FIG. 10 is a diagram showing an example of a recording laser beam according to the present invention in which the irradiation time is corrected according to the immediately preceding blank length. FIG. 11 is a diagram showing an example of a recording laser beam whose irradiation time is corrected according to the length of a pit to be formed. 12 is a diagram showing an eye pattern of a reproduced signal of a pit formed by the laser beam of FIG. FIG. 13 is a diagram showing a relative ratio of jitter to recording power of a reproduced signal of a pit formed by the laser light of FIG. 11; 14 is a diagram showing a relative ratio of an error occurrence rate to a recording power of a reproduced signal of a pit formed by the laser light of FIG. 11; FIG. 15 is a diagram showing a pit length shift when the irradiation time is corrected according to the immediately preceding blank length. FIG. 16 is a diagram showing an example of a pit shape formed using a conventional continuous laser beam. FIG. 17 is a diagram showing a state in which the leading edge is insufficiently melted by using a conventional continuous laser beam. FIG. 18 is a diagram showing a pit shape of each length formed by a conventional continuous laser beam. FIG. 19 is a diagram illustrating an example of a divided laser beam and an example of a pit shape formed by the divided laser beam. FIG. 20 is a diagram showing an example of a pit shape of each length formed by split laser light. FIG. 21 shows a case where pits are formed by continuous laser light,
FIG. 9 is a diagram illustrating jitter characteristics when a pit is formed by split laser light. FIG. 22 shows a case where pits are formed by continuous laser light,
FIG. 9 is a diagram showing a disk reflectance characteristic at the time of reproduction when pits are formed by split laser light. FIG. 23 is a diagram illustrating another example of the split laser light. FIG. 24 is a diagram illustrating another example of the split laser light. FIG. 25 is a diagram showing a relative ratio of recording power to an error derivation ratio under the setting conditions of Table 7. FIG. 26 is a diagram showing another example of the split laser light. FIG. 27 is a characteristic diagram showing a relationship among a recording pit width, a jitter, a tracking error signal amplitude, and a reflectance. FIG. 28 is a diagram illustrating another example of the split laser light. FIG. 29 is a diagram illustrating another example of the split laser light. [Description of Signs] 1 Optical disk 2 Recording device 3 Reproducing device 16 'Pregroove

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-100248 (JP, A) Fuji Film Res & Dev No. 35 p. 58-65 Compact Disc Reader (Revised 3rd Edition) p. 103-104 (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B ^7/ 00-7/30

Claims (1)

(57) [Claims] The recording surface is formed of a material that can be recorded by a semiconductor laser and has a mirror portion reflectance of 59 to 75%, and the recording surface has a depth of 20 on the side where laser light is incident.
An optical disc recording carrier, wherein a pregroove of nm to 50 nm is formed, a mechanical dimension is made to conform to a standard dimension of a read-only optical disc, and recorded so that it can be reproduced by a reproduction apparatus for a read-only optical disc.