JPH07225952A - High density recording and reproducing system for optical disk - Google Patents

Abstract

PURPOSE:To surely reproduce recording pits having a minimum recording length by adjusting a laser power so that a reproducing signal at a part where an mimute pit string having a minimum recording pit length is preliminarily made into a format becomes maximum. CONSTITUTION:A reference pit string 59 for a super-high resolution laser control, a wobble pit string 57 for a tracking, a pit 58 forming a pattern for a wobble positional decision, and a sector pattern 60 are preliminarily made into a format on a disk 10. Then, data of a preformat part are reproduced in a comparator and amplifier circuit 47 and PLL data are generated in a PLL circuit 49 by a pattern discriminated by a pattern matching circuit 48. Next, a laser power control part 52 changes reproducing laser powers at each pit of a super-high resolution reference pattern little by little by using a timing signal based on the output of the circuit 49 from a timing generating circuit 50 and holds a laser power with which the reproducing signal becomes maximum at this time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high density recording / reproducing system for an optical disc.

[0002]

2. Description of the Related Art FIG. 9 is a principle diagram of a conventional high-density reproduction system disclosed in, for example, Japanese Patent Laid-Open No. 5-12673. In the figure, 1 is a laser beam for recording / reproducing, 2 is an objective lens for focusing the laser beam 1, 3 is a temperature-dependent transmittance variable medium for varying the reflectance or transmittance of the medium, Reference numeral 4 denotes an optical recording / reproducing layer for recording / reproducing information.

FIG. 10 is a diagram showing the medium transmittance of the temperature-dependent transmittance variable medium shown in FIG. 9 with respect to the medium temperature. FIG. 11 shows the principle of high density reproduction using the medium of FIGS. 9 and 10. In the figure, 5 is the moving direction of the disk, 6 is a detection area which is a light spot by the laser beam 1, and 7 is recording. Recording marks written on the reproducing layer 4,
Reference numeral 8 is a high temperature region of the medium due to the light spot 6, and 9 is an actual data reproducing portion where the high temperature region 8 having a high medium transmittance and the detection region 6 overlap.

FIG. 12 is a diagram showing the principle of forming a recording mark smaller than the light spot 6. In FIG.
Is a disk, 11 is a high temperature region in the light spot, 12
In the case where the recording film of the medium is a phase change medium, indicates the temperature at which the phase change occurs, and 13 indicates the temperature distribution in the light spot.

FIG. 13 is a diagram showing the principle of high-density reproduction when a magneto-optical medium is used. In the figure, 14 is a reproducing layer which is initialized by a large external magnetic field and magnetically transfers in a high temperature region, and 15 is a reproducing layer. A recording layer on which information is recorded. 14
9 is a comparison between the reproduction signal level in the case of using the high-density recording method using the super-resolution principle shown in FIGS. 9 to 13 and the reproduction signal level of a normal optical disk.

FIG. 15 is a block diagram of an optical disk device in a conventional high density recording / reproducing system. In the figure, 1
6 is a disk motor for rotating the disk 10,
17 is an actuator for driving the objective lens 2,
Reference numeral 18 is an optical head for emitting a laser beam to reproduce a signal, 19 is a signal from a photodetector of the optical head 18, 20 is a minute signal amplifier circuit for amplifying a minute signal from the photodetector, and 21 is A waveform equalization / detection circuit for reproducing data from the reproduction signal from the minute signal amplification circuit 20, a reproduction data 22 and a tracking control circuit 23 for controlling the objective lens 17 and always positioning the light spot at the track center. , 24 is a focus control circuit for controlling the objective lens 17 so that the light spot is always focused on the disk surface, 25 is a system control circuit for controlling the entire optical disk drive, and 26 is an output of the control circuits 23 and 24. An actuator drive signal for driving the actuator 17, 27 is a laser beam emitted from the optical head. Auto laser power control circuit for controlling the over, 28 is a recording and reproducing spot diameter adjusting circuit for controlling the variable and recording and reproducing spot diameter a target value of automatic laser power control circuit 27.

FIG. 16 is a block diagram showing details of the laser power control portion in the block diagram of FIG. In the figure, 29 is a deflecting prism for spectrally splitting a laser, 30 is a laser, 31 is a photodetector for receiving reflected light from the disk and converting the light into electric power, and 32 is a portion of outgoing laser light. It is a photodetector for receiving light and converting light into electricity. 33 and 34 are IV conversion circuits for converting the output currents of the photodetectors 31 and 32 into voltages, and 35 and 34, respectively.
Reference numeral 36 is an integrator for forming a control loop, 37 is a subtractor for comparing with a reference reflected light amount 38, 39 is a phase compensation circuit for forming a control loop, 40 is an automatic laser power control loop and a light spot diameter. A subtraction circuit for coupling with the adjustment loop, 41 is an amplifier for compensating the loop gain, and 42 is a laser driver for driving the laser 30.

FIG. 17 is a block diagram for controlling the recording / reproducing spot diameter so that the reproduction signal amplitude becomes maximum. In the figure, 43 is a reproduction signal amplitude detection circuit, 44 is an A / D converter for loading the amplitude detection information from the reproduction signal detection circuit into a microcomputer, and 45 is a command value from the microcomputer for instructing the optimum spot diameter. It is a D / A converter for converting into an analog voltage.

Next, a conventional operation will be described with reference to the drawings.
Optical disc devices generally have a smaller layer storage capacity than magnetic tape devices and the like, and are not particularly suitable for recording signals such as digital moving images. However, a technique for compressing and recording video information such as JPEG, MPEG, H261, etc., instead of recording the digital moving image signal as it is, is being developed, and it is becoming a situation in which it can be sufficiently recorded in an optical disc device.

However, the current optical disk device (CD or O
In DD), the total storage capacity per disk is still small, and there is a problem in recording digital moving image information for a long time even if a compression technique is used. Therefore, a method using a short-wavelength laser has been considered, but it is difficult to realize a green laser or a blue laser capable of high density with a semiconductor at present, and a high-density method that does not rely on a short-wavelength laser is used to some extent. Technology was desired.

9 to 17 described as a conventional method
The above-mentioned methods show a basic method that can achieve high density without relying on this short-wavelength laser, and particularly FIGS. 9 and 10 show the basic principle thereof. As shown in FIG. 9, a laser beam 1 is irradiated during reproduction and is focused on the disk medium surface by the objective lens 2. At this time, the structure of the medium is such that the temperature-dependent transmittance variable medium 3 capable of changing the reflectance or transmittance of the medium and the optical recording / reproducing layer 4 for recording / reproducing information.
The temperature-dependent transmittance variable medium 3 has the property that the medium transmittance changes as the medium temperature rises as shown in FIG.

The temperature-dependent transmittance variable medium 3 is generally well known as, for example, a phase change medium. Needless to say, the transmissivity and the reflectivity are equivalent to each other. Recording by the phase change method is performed by irradiating a high-power light spot for a short time to rapidly heat and quench the temperature above the melting point to form an amorphous phase that is fixed while the atomic arrangement is disturbed, and the erasing is crystallized. It is carried out by gradually heating and gradually cooling above the crystallization temperature to restore the atomic arrangement to an ordered crystalline state. In this case, recording and erasing are performed by changing the amount of light emitted from the laser, and reproduction is a method that captures the change in the amount of reflected light.

Here, if the disk is rotating, a physical phenomenon as shown in FIG. 11 occurs. FIG. 11 shows the principle of high-density reproduction using the medium of FIGS. 9 and 10. When the disk continues to move in the moving direction 5 as shown in the figure, a light spot of laser light 1 is emitted. A gap occurs between the region 6 and the region 8 where the medium has a high temperature due to the light spot 6. At this time, the portion where the optical head reads the data is the portion of the light spot 6, but since the light transmittance or the light reflectance is low in a region where the medium temperature is low, the portion 9 that actually contributes to signal reproduction is the medium. The high temperature region 8 having a high transmittance and the detection region 6 overlap with each other to form an actual data reproducing portion.

Therefore, even a small recording mark 7 which cannot be reproduced by the reproduction light spot due to the limitation of its spatial resolution can be reproduced. Such a method is called a super-resolution phenomenon, but the above shows a method using a temperature-dependent variable reflectance / transmittance medium. FIG. 13 shows an example of this in a magneto-optical medium, which utilizes that the region where the medium temperature is high and the reproducing light spot are displaced when the medium is moved. In the super-resolution phenomenon in this magneto-optical disk, the reproduction layer is erased in advance with an initialization fossil and the perpendicular magnetization information of the recording layer 15 is transferred in the high temperature region of the medium, so that the medium transmittance is the same as in FIG. The actual data is reproduced in the portion where the high temperature area 8 where the temperature is high and the detection area 6 overlap. In the method using such a super-resolution phenomenon, as shown in FIG. 14, even if the recording density is higher than that of an ordinary disk, there is no limitation due to the spatial resolution.

With the method described above, it is possible to realize the super-resolution phenomenon even when the magneto-optical recording is used or the phase change recording is used. Since it is the method of reproducing the actual data in the part where the high temperature region where the temperature is high and the detection region overlap, the variation in the medium thickness that causes a slight change in the medium temperature, the variation in the device temperature and the laser power, The distribution in the high temperature region also changes due to changes in linear velocity. Further, even at the time of recording, the temperature at which the medium is recorded is set to 11 areas in the temperature distribution 13 of the light spot as shown in FIG. 12 to form a spot sufficiently smaller than the light spot diameter. Even a slight change in medium temperature makes it impossible to record / reproduce minute pits.

Therefore, in the conventional high-density reproducing method, the signal from the photodetector of the optical head 18 in the block diagram of FIG. 15 and the minute signal amplification circuit 19 for amplifying the minute signal from the photodetector 20 are provided. Using the signal amplified by, configure the auto laser power control circuit 27 to control the laser power emitted from the optical head, and further change the target value of the auto laser power control circuit 27 to control the recording / playback spot diameter. The actual light spot diameter 9 is adjusted by providing a recording / reproducing spot diameter adjusting circuit 28 for this purpose.

As a concrete method of adjusting the light spot diameter in FIG. 15, first, the medium reflectance or the transmittance is detected,
There is a real-time control method. FIG. 16 is a block diagram showing details of the laser power control portion in the block diagram of FIG. 15, which is based on the output of the photodetector 13 for receiving the reflected light from the disk and converting the light into electric power. It is compared with a comparator 37 and used as a reference for a general auto laser power control loop. In general automatic laser power control, the light that is obtained by splitting a part of the emitted laser light is received
While only the emission power of the laser 30 is controlled on the basis of the output of the photodetector 32 for electrical conversion, in this method, a correction loop for keeping the medium reflectance constant is added.

Further, as shown in FIG. 17, there is also a method of controlling the recording / reproducing spot diameter so that the reproduction signal amplitude of the minute pit becomes maximum. Here, based on the output of the reproduction signal amplitude detection circuit 43, the microcomputer 46 performs hill climbing control via an A / D converter for incorporating the amplitude detection information from the reproduction signal detection circuit into the microcomputer. As for the hill climbing control result, the optimum spot diameter is instructed by the A / D converter 45, and the reference value of the automatic laser power control loop is corrected and controlled.

As described above, the reference (reference value) of a general automatic laser power control circuit is corrected so that the reproduction signal amplitude becomes maximum or the medium reflectance becomes a predetermined value. The light spot diameter 9 can be adjusted.

[0020]

In the conventional laser power control method as described above, a reliable super-resolution phenomenon occurs in order to reproduce a minute pit, and the apparent light spot diameter is always kept constant. In order to reliably reproduce the recording pit with the shortest pit length, there are the following problems.

In the method of controlling the laser power so that the reproduction signal amplitude becomes maximum, the optimum laser power value also changes each time the pit length of the recording signal changes. The power is not compatible. For example, when the pit length of the signal is large enough not to require the super-resolution phenomenon, there is a problem that the reproduction signal amplitude increases as the laser power increases.

Further, there is a problem that it is not possible to distinguish which state of the reflectance is the state in which the optimum super-resolution occurs by only keeping the reflectance constant.

Further, in the optical disc apparatus for recording, it is necessary to keep the linear velocity of the disc constant, and it is necessary to take out the rotation reference signal for that purpose from the disc, but in the disc which is not preformatted. ,
There is a problem that the rotation reference signal cannot be obtained.

The present invention has been made in order to solve the above-mentioned problems, and causes a reliable super-resolution phenomenon, always keeps the apparent light spot diameter constant, and realizes the shortest recording pit length. An object of the present invention is to obtain a high-density recording / reproducing system for an optical disc that enables reliable reproduction and facilitates tracking during recording and data retrieval during reproduction.

[0025]

According to a first aspect of the present invention, there is provided a high density recording / reproducing method for an optical disc according to the present invention, wherein in order to optimally perform a super-resolution phenomenon, a recording pit has a shortest recording pit length. Pre-formatting the columns on the disk substrate and adjusting the laser power so that the reproduced signal at this part is maximized so that the reproduced laser power that always produces a reliable super-resolution phenomenon can be searched. Is.

In the second aspect, the first optimum laser power value is held up to the next preformat section so that the optimum super-resolution phenomenon can be maintained at all times.

In addition, in order to optimally perform the super-resolution phenomenon, a fine pit train having a shortest recording pit length is pre-formatted on the disc substrate in advance, and the disc reflection at this portion is performed. By adjusting the laser power so that the rate becomes constant, the disk reflectance that always causes a reliable super-resolution phenomenon is searched.

According to a fourth aspect of the present invention, the disc reflectivity in the third means is held until the next preformatted portion so that an optimum super-resolution phenomenon always occurs.

According to a fifth aspect of the present invention, the pit row portion of the unevenness that is sufficiently smaller than the light spot diameter pre-formatted on the disk substrate has a pit shape that is short in the line direction and long in the track direction. The shape of the light spot is substantially the same as that of the super-resolution phenomenon.

According to a sixth aspect of the present invention, in the pit row portion of the unevenness which is sufficiently smaller than the light spot diameter pre-formatted on the disk substrate, pits substantially the same as the light spot diameter with respect to the center of the track. It is configured so as to include two wobble pits which are shifted in the front-back direction in the track direction so that a track error signal can be obtained.

According to a seventh aspect of the present invention, a predetermined pattern is pre-formatted before and after the wobble pit so that the position of the wobble pit can be detected during reproduction, and when the reproduction laser beam passes through the two wobble pits,
The amplitude of the reproduction signal is detected and held, and the difference is taken to detect the deviation between the spot position and the position of the track center due to the reproduction laser light.

According to the eighth aspect of the invention, the reproduction signal amplitude from the wobble pit is held at the time of reproduction, and the tracking control is performed by obtaining the difference.

According to a ninth aspect of the invention, in addition to the pit row portion of the unevenness which is sufficiently smaller than the light spot diameter pre-formatted on the disk substrate, the sector address is almost the same as the light spot diameter. Is recorded and can be searched.

Further, in claim 10, the address is
It is formed for each field or frame of the digital moving image recorded on the optical disc,
It is possible to search in screen units.

In the eleventh aspect of the invention, a radial portion is provided between a portion of the inner circumference of the disc for rotating the disc that is clamped to the motor and a portion where the medium is formed.
A code is printed so as to discriminate between a high-density disc using a medium of the super-resolution phenomenon and a read-only disc formed by only concave and convex pits.

According to a twelfth aspect, by irradiating the print code with an LED (laser diode),
This reflected light is reproduced and discriminated.

In the thirteenth aspect of the present invention, the information sector in the portion in which the information of the digital moving image is recorded is composed of image fields or frame units, and the reproduction light spot diameter on the disc substrate is set at the head portion of the frame. In addition to having the address information formed by the concave and convex pits of almost the same size, in the part where the program data other than the image data and the control data are recorded,
In addition to image data, computer program data can also be stored by forming sub-sectors into which the above-mentioned sector in which the sub-address is recorded by phase change or write-once is further subdivided.

According to a fourteenth aspect of the invention, the wobble pit is formed for each of the sub-sectors to reduce the sampling phase delay in the tracking error signal.

[0039]

The high-density recording / reproducing system for an optical disk according to the present invention is characterized in that, in claims 1 to 4, a minute pit string having a shortest recording pit length is pre-formatted on a disk substrate in advance, By adjusting the laser power so that the reproduced signal in the formatted part is maximized, or by adjusting the laser power so that the disc reflectivity in this part is constant, the reality of the super resolution phenomenon The reproduction spot diameter is always kept to match the shortest recording pit length.

According to a fifth aspect of the invention, the pit row portion of the unevenness which is sufficiently smaller than the light spot diameter pre-formatted on the disk substrate is short in the line direction,
By making the pit shape long in the track direction, the shape is substantially the same as the light spot shape at the time of the super-resolution phenomenon, and a larger reproduction signal amplitude can be obtained.

In the sixth to eighth aspects, in the uneven pit row portion pre-formatted on the disk substrate, the pits having substantially the same light spot diameter are displaced forward and backward in the track direction with respect to the center of the track. Two
It is configured to include two wobble pits, and a certain pattern is pre-formatted before and after the wobble pit so that the position of the wobble pit can be detected during reproduction. By detecting the difference between the spot position and the position of the track center due to the reproduction laser beam by holding the reproduction signal amplitude after detection and holding the difference, the tracking without offset can be performed.

In the ninth and tenth aspects of the invention, in addition to the pit row portion of the unevenness which is sufficiently smaller than the light spot diameter pre-formatted on the disk substrate in advance, the sector is formed in the pit row almost the same as the light spot diameter. By recording the address of each image and forming this address for each field or frame of the digital moving image recorded on the optical disc, it is possible to easily search for each image for each screen. .

In the eleventh and twelfth aspects, the super-resolution phenomenon of the super-resolution phenomenon occurs in the radial portion between the portion of the inner circumference of the disc for rotating the disc that is clamped to the motor and the portion where the medium is formed. By printing a code that distinguishes between a high-density disc that uses a medium and a read-only disc that is formed by only concave and convex pits, the amplification factor of the reproduction signal and the threshold for data discrimination are adapted to the disc type. It is a thing.

In the thirteenth and fourteenth aspects, the information sector in the portion in which the information of the digital moving image is recorded is constituted by the image field or the frame unit, and the reproduction light spot is formed on the disc substrate at the head portion of the frame. The sector that has address information formed by concave and convex pits of approximately the same size as the diameter, and has a subaddress recorded by phase change or write-once in the portion where program data other than image data and control data are recorded. The sub-sectors are further divided into sub-sectors so that not only video information but also general computer program data can be easily searched.

[0045]

【Example】

Example 1. FIG. 1 is a block diagram showing a high density recording / reproducing system for an optical disc according to an embodiment of the present invention. In the figure, reference numeral 47 is a comparator and an amplifier circuit for discriminating binary data, and 48 is a discriminating pattern for discriminating a wobble pit pre-formatted on the disk 10 or a reference pattern signal for super-resolution. A pattern matching circuit, 49 is a PLL circuit for generating a reference clock based on the output of the pattern matching circuit, and 50 is a timing generation circuit for generating timing signals of respective preformat signals and recording signals based on the output of the PLL circuit 49. Reference numeral 51 denotes a hold circuit for detecting the amount of track deviation from the wobble signal pre-formatted on the disk 10, and 52 denotes detection and control of the optimum laser power from the super-resolution reference pattern signal pre-formatted on the disk 10. With the laser power control unit for That.

Reference numeral 53 is a data detection circuit for detecting data from a binarized reproduction signal, and 54 is a portion of the inner circumference of the disc for clamping the motor and a portion where the medium is formed. A disc type discriminating circuit for reading a code discriminating between a high-density disc using a medium of a super-resolution phenomenon and a read-only disc formed by only concave and convex pits, which is printed in a radius portion between
Is a phase control circuit for controlling the rotation phase of the motor based on the output of the pattern matching circuit, and 56 is a motor driver for driving the disk motor 16.

FIG. 2 is a diagram showing the operation of the laser power control section of FIG. In the figure, 57 to 60
Is a signal pit sequence pre-formatted on the disc 10, 59 is a super-resolution laser control reference pit sequence, 57 is a wobble pit sequence for tracking, and 58 is a pit for forming a wobble position determination pattern in combination with the wobble pit sequence. , 60 is a sector pattern representing the address of the sector. Reference numeral 61 shows the operation state of the reproduction laser power in the time axis direction, 62 is the reproduction signal amplitude at this time, 63 is the binarized data, and 64 is the PLL.
The data is.

FIG. 4 is a diagram showing a software control subroutine in the laser power control section. Next, the operation will be described with reference to the drawings. In FIG. 1, a comparator and an amplifier circuit 47 for discriminating binary data reproduces data in a preformatted portion, and based on the binarized reproduced signal 63, wobble pits preformatted on the disk 10 or for super resolution. Reference pattern signal 59
The PLL data 48 is generated by the PLL circuit 48 according to the pattern determined by the pattern matching circuit 48 for identifying the determination pattern for determining the. Further, the timing generation circuit 50 generates timing signals for each preformat signal and recording signal based on the output of the PLL circuit 49. As described above, the timing signals of the super-resolution reference pattern and the tracking wobble pattern can be obtained.

Next, using this timing signal, the laser power controller 52 changes the reproduction laser power in each pit of the super-resolution reference pattern of FIG. 2 little by little as 61 based on the subroutine of FIG. Then, the maximum laser power of the level of the reproduction signal 62 at this time is held after the super-resolution reference pattern. In this way, it is possible to set the optimum laser power at the time of super-resolution in the pre-formatted reference pattern area 59. Since the reference pattern area 59 is arranged for each sector, it is possible to deal with a difference between the inner and outer circumferences of the disc, a variation in linear velocity, and the like. Further, in this reference pattern area, since the shortest pit length is a fixed pattern, it is possible to accurately extract the laser power during reproduction.

Example 2. FIG. 3 is a diagram showing the operation in the laser power control portion of FIG. 1, showing the operating principle of measuring the reflectance and setting the laser power at the time of super-resolution, and in the figure, 59 'is the reflectance. Measurement area, 59
(A) is the state of the phase change medium in the reflectance measurement area of 59 ', and represents the amorphous rate area. 59 (b) is a crystalline region,
61 'is a reproduction laser power and 62' is a reproduction signal level.

Next, the operation will be described. FIG. 3 shows the operation of the method of measuring the reflectance from the disc and setting the optimum laser power at the time of super-resolution in the pre-format section other than the section for recording and reproducing data.
The configuration of the device can be realized by a block diagram configuration similar to that of FIG. However, in this case, not the super-resolution reference pattern such as 59 in FIG. 2 which is provided in the preformat section, but an area in which nothing is preformatted (a reflectance measurement area 59 ′) is provided.

In the reflectance measurement region, in the case of a phase change medium, the crystalline region 59 (b) and the amorphous region 59 (a) are written in advance at the time of recording, and at the time of reproduction, as in 61 'in FIG. Change the playback laser power. At this time, the reproduction signal level equivalent to the medium reflectance in the laser power setting area 59 'is as shown in 62', but the intermediate value ho between the minimum value a and the maximum value b of the reflectance in the crystal area 59 (a). And calculate (where intermediate level
E = (i + b) / 2)

The reproducing laser power (g) at this time is stored. Similarly, even in the amorphous region, the reproduction laser power is changed to calculate the intermediate level (f) between the minimum value (c) and the maximum value (d) of the reproduction signal level, and the reproduction laser power (h) at this time is calculated. Remember. Next, the average value (ri) of (to) and (h), which is the above calculated reproduction laser power,
It is retained after the reflectance measurement area. As described above, by providing the dedicated area for measuring the medium reflectance, it is possible to accurately set the laser power at the time of super-resolution.

Example 3. FIG. 6 is a diagram showing a preformat portion of the optical disc according to the present invention. In the super-resolution method, as shown in FIG. 10 which is a conventional embodiment, a substantial reproduction spot is an area 9 shown by an area 9 in which a circular light spot 6 and a high temperature area 8 overlap each other. ing. The substantially suitable reproduction area 9 is shorter in the line direction than the area 6 which is a general light spot.

Therefore, the pit shape of the uneven pit row portion which is pre-formatted in advance on the disk substrate for super-resolution reproduction is sufficiently smaller than the above-mentioned light spot diameter, and the pit shape is short in the line direction and long in the track direction. As a result, the shape of the light spot becomes substantially the same as the shape of the light spot at the time of the super-resolution phenomenon, and a larger reproduced signal amplitude can be obtained.

Example 4. FIG. 5 is a diagram for explaining an optical disc according to the present invention, in which (a) is a preformat section,
(B) shows the appearance of the disc, and (c) shows the reproduced signal state. In the figure, reference numeral 65 is a wobble pit for detecting a tracking error signal and a discrimination pattern portion for determining the position of the wobble pit.

In this wobble pit portion, in the uneven pit row portion which is pre-formatted in advance on the pre-formatted disc substrate, pits having substantially the same light spot diameter as described above are displaced forward and backward in the track direction with respect to the center of the track. The wobble pit is configured to include two wobble pits, and a certain pattern including the wobble pits is discriminated by the pattern matching circuit 48 of FIG. 1, and the reproduction laser light passes through the two wobble pits by the hold circuit 51. In this case, each reproduction signal amplitude is detected and then held, and the difference is taken to detect the deviation between the spot position and the track center position due to the reproduction laser light, thereby enabling tracking without offset. Is.

In order to obtain a tracking signal with this wobble pattern, at least 2 per track of the disc.
It goes without saying that unless 000 or more patterns are provided, the tracking error signal has a phase shift due to sampling, which makes track tracking impossible. Generally, in an optical disk device using the push-pull tracking method, an offset signal is mixed with the sensor signal as the objective lens moves. However, in the sample servo system using this wobble pit, an error signal is detected by time division and the difference is taken,
The offset signal accompanying the movement of the objective lens is canceled out, and it is possible to obtain an error signal without offset.

In this wobble pit for servo detection, it is necessary to obtain error information irrespective of the super-resolution phenomenon in order to prevent the servo from being displaced (reflectance at the time of super-resolution.
Needless to say, the pit diameter should be set so that it can be detected with a normal light spot diameter (without using super-resolution), because it should not be affected by the change in transmittance.

By arranging the wobble pits at regular intervals in the linear direction, the wobble pits are used as rotation reference information of the disc during reproduction, and the constant linear velocity control (CLV) operation can be performed by the phase control circuit 55 of FIG. It will be possible. As a method for controlling the constant linear velocity rotation at the time of recording using a recordable disc, a method in which a track guide groove is meandered and a modulation component of a reproduction signal due to the meandering is used as a rotation detection signal is known. However, in the method of pre-formatting the wobble pit, the tracking error detecting pit itself serves as a rotation detection signal.

Example 5. A fifth embodiment of the present invention will be described with reference to the drawings. FIG. 5A shows a pre-formatted portion of the optical disc. In the figure, reference numeral 66 denotes a portion in which a super-resolution reference pattern signal and sector address information are recorded.

The sector address is recorded in a pit row which is substantially the same as the above-mentioned light spot diameter, except for the pit row portion which is pre-formatted in advance on the disk substrate and is sufficiently smaller than the above-mentioned light spot diameter. By forming each field or frame of the digital moving image recorded on the optical disc, each image can be easily searched for each screen.

Example 6. Figure 5 (b) shows the appearance of the disc.
(C) shows a reproduced signal state, and in the figure, 68
Is a sector which is one unit of information recording, and 69 is a print code for discriminating the type of disc.

Data is detected from the binarized reproduction signal by the data detection circuit 53 in FIG. 1. At this time, the disc is rotated because the data discrimination level differs depending on the type of disc as shown in FIG. 5C. The disc type discriminating circuit 54 for reading the code 69 printed on the radius portion between the portion of the inner circumference of the disc to be clamped to the motor and the portion where the medium is formed. This is handled by discriminating between a high-density disc using a disc and a read-only disc formed by only concave and convex pits, and switching the threshold level of data detection and the amplification factor of a reproduction signal described above.

Needless to say, it is also possible to write the command value of the number of revolutions, the data capacity, etc. in this code. Also, these codes are LE as shown in FIG.
It is performed by irradiating D light and reading the reflected light with a photodiode or the like.

Example 7. FIG. 7 is a diagram showing a sector structure of information in a high density optical disc according to the present invention. In the figure, FIG. 7A shows a pre-formatted portion indicating the head portion of a sector, 70 is a laser power setting area for super-resolution, 71 is a wobble pit area for tracking error detection, 72 is an address area, and 73 is a data recording area. Is. FIG. 7B shows a wobble mark portion in a sector, and 74 shows the arrangement from 70 to 73 in one sector. FIG. 7 (c) shows a large information area in which some of the sectors 74 are gathered. Reference numeral 75 denotes a pit row of the preformat portion at the head portion thereof, and 76 denotes a sector arrangement of the large information area. It is a thing. 8 (a), (b) and (c) are shown in FIG.
It is a variation of the data array of the large information area of (c).

Next, the operation will be described. The information sector in the portion where the information of the digital moving image is recorded is composed of image fields or frame units, and is formed at the beginning of the frame by uneven pits of the same size as the reproduction light spot diameter on the disc substrate. The sub-address 75-E is recorded by phase change or write-once in a portion where the program data and control data other than the image data are recorded while having the address information 72.

For example, digital moving image data (G) 1 to (G) n are recorded, and search data for inserting or editing this moving image into another still image or the like is stored in the moving image data. If you want to record at the beginning,
The sector array is configured as shown in (a). Further, when the amount of character information, voice, and computer program information is large with respect to still image data, the configuration is as shown in FIG. Further, when the moving image data and the computer program and the like are mixed, the configuration is as shown in FIG.

In this case, although the digital video data has a large amount of information, it is not necessary to set fine address information. Further, if one screen has one address information, fine address information is not necessary except in a special case where the inside of the screen is divided and edited. Further, in the communication system moving image compression algorithm such as the MPEG system or H261, the data rate for each image unit is constant.
Therefore, it is desirable that the image data be recorded / reproduced in units of pre-formatted sectors on the disc. However, since the amount of information of computer data and voice / character data is not constant, it is necessary to set fine sectors. Therefore, as in the present invention, a method of recording the address itself of the program data by the phase change is desired.
In this case, it is considered desirable to write before and after the wobble pits for tracking, which are present in 2000 or more per disk circumference.

By forming sub-sectors obtained by further dividing the preformatted sector in this way, not only video information but also general computer program data can be searched easily.

[0071]

As described above, according to the first and second aspects of the present invention, since the laser power setting region at the time of super-resolution reproduction is set in the pre-formatted region, the super-resolution reproduction is performed. You can now set the exact laser power. In particular, by adjusting the laser power so that the preformat reproduction signal is maximized in this power setting area, a substantial reproduction area can be specified even for fluctuations in linear velocity, variations in medium thickness, and changes in ambient temperature. It has become possible to keep the size of.

Further, according to the third and fourth aspects of the present invention, since the laser power setting area at the time of super-resolution reproduction is set in the pre-formatted area in advance, accurate at the time of super-resolution reproduction. Laser power can now be set. In particular, by accurately grasping the medium reflectivity of the preformatted portion in this power setting area, a substantial reproduction area can be set to a predetermined size even with variations in linear velocity, variations in medium thickness, and changes in ambient temperature. It has become possible to keep

According to the fifth aspect of the present invention, the shape of the focused spot is short in the line direction and long in the track direction, so that it is similar to the substantial light spot shape at the time of the super-resolution phenomenon. The shape makes it possible to suppress the jitter component in the reproduced signal to be low and improve the C / N of the reproduced signal.

According to the sixth and seventh aspects of the present invention, since the wobble pit is formed in the pre-format portion, it is possible to obtain a tracking error signal without a sensor offset, and the tracking detection optical system is simple. Be converted.

According to the eighth aspect of the present invention, by disposing the wobble pits at a constant interval, it becomes possible to rotate the disc with constant linear velocity control during recording.

According to claims 9 and 10 of the present invention,
Since the address code is written for each image of the digital moving image data written on this disc, the image data can be searched.

According to the eleventh and twelfth aspects of the present invention, a code for discriminating the type of the disc is printed between the disc clamp portion and the medium. Distinguish between the density disc,
It became possible to reproduce both.

According to the thirteenth and fourteenth aspects of the present invention, since program data of a computer or the like has a method of writing an address as recording data, high density recording of multimedia data in which moving image data and program data are mixed is performed. Also became available.

[Brief description of drawings]

FIG. 1 is a block diagram showing a high density recording / reproducing system for an optical disc according to an embodiment of the present invention.

FIG. 2 is a diagram showing an operation in a laser power control portion of FIG.

FIG. 3 is a diagram showing an operation in a laser power control portion of FIG.

FIG. 4 is a diagram showing a subroutine of software control in the laser power control unit of the present invention.

5A and 5B are views for explaining an optical disc according to the present invention, in which FIG. 5A shows a preformat section, FIG. 5B shows an appearance of the disc, and FIG. 5C shows a reproduced signal state.

FIG. 6 is a diagram showing a pre-format section of the optical disc according to the present invention.

FIG. 7 is a diagram showing a sector structure of information in a high density optical disc according to the present invention.

FIG. 8 is a diagram showing a sector structure of information in a high density optical disc according to the present invention.

FIG. 9 is a principle diagram of a conventional high-density reproduction system.

FIG. 10 shows the temperature-dependent transmittance variable medium of FIG.
It is a figure which shows the medium transmittance with respect to a medium temperature.

11 is a diagram showing the principle of high-density reproduction using the medium of FIGS. 9 and 10. FIG.

FIG. 12 is a diagram showing the principle of forming a recording mark smaller than the light spot 6.

FIG. 13 is a diagram showing the principle of high-density reproduction when a magneto-optical medium is used.

FIG. 14 is a diagram comparing the reproduction signal level in the case of using the high-density recording method using the super-resolution principle of FIGS. 9 to 13 with the reproduction signal level of a normal optical disc.

FIG. 15 is a block diagram of an optical disc device in a conventional high-density recording / reproducing system.

16 is a block diagram showing details of a laser power control portion in the block diagram of FIG.

FIG. 17 is a block diagram for controlling the recording / reproducing spot diameter so that the reproduction signal amplitude is maximized.

[Explanation of symbols]

 1 Laser Light 2 Objective Lens 3 Temperature Dependent Transmittance Variable Medium 4 Optical Recording / Reproducing Layer 5 Disc Moving Direction 6 Detection Area 7 Recording Mark 8 High Temperature Area of Medium 9 Data Reproducing Area 10 Disk 11 High Temperature Area in Light Spot 12 Phase Change Temperature 13 Temperature distribution 14 Playback layer 15 Recording layer 16 Disk motor 17 Actuator 18 Optical head 19 Signal from photodetector 20 Small signal amplification circuit 21 Waveform equivalent / detection circuit, 22 Playback data 23 Tracking control circuit 24 Focus control circuit 25 System control circuit 26 Actuator drive signal 27 Auto laser power control circuit 28 Recording / playback spot diameter adjustment circuit 29 Deflection prism 30 Laser 31, 32 Photodetector 33, 34 IV conversion circuit 35, 36 Integrator 37 Subtractor 39 Phase compensation circuit 40 Subtraction circuit 41 Amplifier 42 Laser driver 43 Reproduction signal amplitude detection circuit 44 A / D converter 45 D / A converter 47 Comparator and amplification circuit 48 Pattern matching circuit 49 PLL circuit 50 Timing generation circuit 51 Hold circuit 52 Laser power Control unit 53 Data detection circuit 54 Disc type determination circuit 55 Phase control circuit 56 Motor driver 57 Tracking wobble pit row 58 Pits forming a pattern for wobble position determination 59 Super resolution laser control reference pit row 60 Sector pattern 61 hours Operating state of reproduction laser power shown in the axial direction 62 Reproduction signal amplitude 63 Binary data 64 PLL data 59 'Reflectance measurement region 59 (a) Amorphous ratio region 59 (b) Crystal region 61' Reproduction laser power 62 'Reproduction signal level 68 Sector 69 Printing code 70 Laser power setting area for super-resolution 71 Tracking error detection wobble pit area 72 Address area 73 Data recording area 74 Array of symbols 70 to 73 in one sector 75 Pre Format pit row 76 sector array

Claims (14)

[Claims] 1. Information is recorded on a first medium layer formed on a disk substrate and undergoes a phase change due to a temperature change caused by a focused laser beam, and a reflectance of the medium phase on the light irradiation side due to the temperature change. Alternatively, using an optical disc on which a second medium whose transmittance changes is formed, a portion where the medium temperature is high is displaced rearward in the scanning direction due to the rotation of the disc, with respect to the portion where the focused spot is irradiated. By adjusting the reproduction laser power of the optical head for irradiating the medium with laser light, the reflectance or the transmittance of the second medium can be changed to be more than the light spot diameter by the converging laser. In the optical disk device for reading the phase change or concave and convex pit information recorded on the first medium layer which is very small, the pre-recording is preliminarily performed on the disk substrate. -High density recording / reproduction of an optical disk characterized by controlling the laser power of the optical head so that the reproduction signal of the preformatted portion is maximized in the pit row portion which is sufficiently smaller than the optical spot diameter that is matted. method. 2. In the laser control system during reproduction,
2. The high density of the optical disc according to claim 1, wherein the optimum laser power value at the time of reproduction, which is determined by the preformatted portion partially formed on the track of the optical disc, is held until the next preformatted portion. Recording / playback method. 3. Information is recorded on a first medium layer formed on a disk substrate and having a phase change caused by a temperature change caused by a focused laser beam, and the reflectance is changed by the temperature change on the light irradiation side of the medium phase. Alternatively, using an optical disc on which a second medium whose transmittance changes is formed, a portion where the medium temperature is high is displaced rearward in the scanning direction due to the rotation of the disc, with respect to the portion where the focused spot is irradiated. By adjusting the reproduction laser power of the optical head for irradiating the medium with laser light, the reflectance or the transmittance of the second medium can be changed to be more than the light spot diameter by the converging laser. In the optical disk device for reading the phase change or concave and convex pit information recorded on the first medium layer which is very small, the pre-recording is preliminarily performed on the disk substrate. -The medium reflectance is measured from the amplitude value of the reproduction signal in the pit row portion that is sufficiently smaller than the optical spot diameter that is matted, and the laser power of the optical head is controlled so that the medium reflectance is always constant. A high-density recording / reproducing system for optical discs characterized by the above. 4. In the laser control system during the reproduction,
3. The high density of the optical disc according to claim 2, wherein the optimum laser power value at the time of reproduction, which is determined by the preformatted portion partially formed on the track of the optical disc, is held until the next preformatted portion. Recording / playback method. 5. Information is recorded on a first medium layer formed on a disk substrate and having a phase change caused by a temperature change caused by a focused laser beam, and the reflectance of the medium phase on the light irradiation side due to the temperature change. Alternatively, using an optical disc on which a second medium whose transmittance changes is formed, a portion where the medium temperature is high is displaced rearward in the scanning direction due to the rotation of the disc, with respect to the portion where the focused spot is irradiated. By adjusting the reproduction laser power of the optical head for irradiating the medium with laser light, the reflectance or the transmittance of the second medium can be changed to be more than the light spot diameter by the converging laser. In the optical disk device for reading the phase change or concave and convex pit information recorded on the first medium layer which is very small, the pre-recording is preliminarily performed on the disk substrate. Pit string portion of sufficiently small irregularities than the spot diameter being Matto is shorter in the linear direction, a high-density recording and reproducing system of the optical disc, characterized in that has a long pit shape in the track direction. 6. Information is recorded on a first medium layer formed on a disk substrate and undergoes a phase change due to a temperature change due to a focused laser beam, and the light reflectance of the medium phase on the light irradiation side due to the temperature change. Alternatively, using an optical disc on which a second medium whose transmittance changes is formed, a portion where the medium temperature is high is displaced rearward in the scanning direction due to the rotation of the disc, with respect to the portion where the focused spot is irradiated. By adjusting the reproduction laser power of the optical head for irradiating the medium with laser light, the reflectance or the transmittance of the second medium can be changed to be more than the light spot diameter by the converging laser. In the optical disk device for reading the phase change or concave and convex pit information recorded on the first medium layer which is very small, the pre-recording is preliminarily performed on the disk substrate. -In the pit row part of the unevenness that is sufficiently smaller than the above-mentioned light spot diameter that is matted, the pits that are almost the same as the above-mentioned light spot diameter include two wobble pits that are shifted back and forth in the track direction with respect to the center of the track. High-density recording / reproducing method for optical disks. 7. The high density recording / reproducing system for an optical disc according to claim 6, wherein a fixed pattern is pre-formatted before and after the wobble pit so that the position of the wobble pit can be detected during reproduction. 8. When the reproduction laser light passes through the two wobble pits, the reproduction signal amplitude of each is detected and then held, and the difference is obtained, whereby the spot position and the track center position due to the reproduction laser light are deviated. 9. The high density recording / reproducing system for an optical disk according to claim 7, wherein the wobble pits are detected at the same time and the wobble pits are arranged at a constant interval in the line direction, and the reproduction signal of the wobble pits is used as a rotation reference signal of the disc during recording / reproduction. . 9. Information is recorded on a first medium layer formed on a disk substrate and undergoes a phase change due to a temperature change due to a focused laser beam, and further, a reflectance due to a temperature change on a light irradiation side of the medium phase. Alternatively, using an optical disc on which a second medium whose transmittance changes is formed, a portion where the medium temperature is high is displaced rearward in the scanning direction due to the rotation of the disc, with respect to the portion where the focused spot is irradiated. By adjusting the reproduction laser power of the optical head for irradiating the medium with laser light, the reflectance or the transmittance of the second medium can be changed to be more than the light spot diameter by the converging laser. In the optical disk device for reading the phase change or concave and convex pit information recorded on the first medium layer which is very small, the pre-recording is preliminarily performed on the disk substrate. -High-density recording / reproducing of an optical disk characterized in that the sector address is recorded in a pit row that is almost the same as the above-mentioned light spot diameter, in addition to the uneven pit row portion that is sufficiently smaller than the above-mentioned light spot diameter. method. 10. The high-density recording / reproducing system for an optical disc according to claim 9, wherein the address is formed for each field or frame of a digital moving image recorded on the optical disc. 11. Information is recorded on a first medium layer formed on a disk substrate and undergoes a phase change due to a temperature change due to a focused laser beam, and further, a reflectance due to a temperature change on a light irradiation side of the medium phase. Alternatively, using an optical disc on which a second medium whose transmittance changes is formed, a portion where the medium temperature is high is displaced rearward in the scanning direction due to the rotation of the disc, with respect to the portion where the focused spot is irradiated. By adjusting the reproduction laser power of the optical head for irradiating the medium with laser light, the reflectance or the transmittance of the second medium can be changed to be more than the light spot diameter by the converging laser. In the optical disc device for reading the pit information due to the phase change recorded in the first medium layer, which is very small, the disc inner circumference for rotating the disc. A high-density disc using the first and second mediums or a read-only or write-once disc formed only with concave and convex pits in the radius portion between the portion clamped to the motor and the portion where the medium is formed. A high-density recording / reproducing system for optical discs, in which a code for determining whether or not is printed. 12. A high-density recording / reproducing system for an optical disk according to claim 11, wherein the printed code reads the reflected light from the LED mounted on the device by a photodiode. 13. Information is recorded on a first medium layer formed on a disk substrate and having a phase change caused by a temperature change caused by a focused laser beam, and the reflectance of the medium phase on the light irradiation side due to the temperature change. Alternatively, using an optical disc on which a second medium whose transmittance changes is formed, a portion where the medium temperature is high is displaced rearward in the scanning direction due to the rotation of the disc, with respect to the portion where the focused spot is irradiated. By adjusting the reproduction laser power of the optical head for irradiating the medium with laser light, the reflectance or the transmittance of the second medium can be changed to be more than the light spot diameter by the converging laser. In the optical disc device for reading the pit information due to the phase change recorded in the first medium layer which is very small, the portion where the information of the digital moving image is recorded. An information sector in an image field or frame unit is composed, and at the beginning of the frame has address information formed by concavo-convex pits of about the same size as the reproduction light spot diameter on the disc substrate, and also, other than image data. In the portion where the program data and the control data are recorded, the first sector is characterized in that sub-sectors are formed by further dividing the above-mentioned sector in which the sub-address is recorded by phase change or write-once. High density recording / reproducing method for optical discs. 14. The high density recording / reproducing method for an optical disc according to claim 13, wherein the wobble pit is formed for each sub-sector.