JPH11191226A - Recording and reproducing device for optical information recording medium and focusing control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the recording/reproducing device for an optical information recording medium and the focusing control method thereof capable of always performing excellent reproducing/recording operation under various conditions. SOLUTION: In the recording/reproducing device of an optical information recording medium for reproducing or recording information on the recording surface of a high density optical information recording medium such as DVD provided with a land area L, a groove area G and a pit address area PA formed between the areas, a microcomputer 400 for controlling the device optimally controls the position of a focusing lens 250 of an optical pickup 200 by learning control while suiting to the land area L and the groove area respectively, also sets an area capable of surely fetching a pit P for recording address information in the pit address area PA in advance and always controls the focusing position by the learning control so as to locate it in the area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium reproducing apparatus for reading and reproducing recorded information from an optical information recording medium in which information is recorded on a disk-shaped medium by pits and the like.
Also, the present invention relates to a recording / reproducing apparatus capable of recording information (hereinafter, simply referred to as a recording / reproducing apparatus for an optical information recording medium), and particularly to an optical information recording / reproducing apparatus for recording / reproducing information on a land-groove type medium. The present invention relates to an improved structure of a medium recording / reproducing apparatus and a method of controlling a focus position which is a focus of an optical reproducing means in such an apparatus.

[0002]

2. Description of the Related Art Conventionally, recorded information is optically read out from an optical information recording medium on which information is recorded by forming pits on a disk-shaped optical recording medium by utilizing a phase change or the like to reproduce the information. Various types of recording / reproducing apparatuses for optical information recording media are known and have already been put to practical use. Particularly, in recent years, as an optical recording medium capable of recording a large amount of information by increasing its information recording density, for example,
A so-called VD (Digital Video Disc) has been proposed and attracted attention, and a part of a reproducing apparatus for reading and reproducing the recorded information has already been marketed.

Meanwhile, in a high-density recording medium such as a DVD or the like, in order to increase the information recording density on the disc-shaped medium, a laser beam having a shorter wavelength than before is used as an optical reproducing means. Further, in order to improve the track pitch density, irregularities called land areas and groove areas are formed on the recording surface of the medium, and information is recorded in these areas. Note that these land areas and groove areas alternately appear every turn following a tracking operation by an optical pickup as an optical reproducing means. Also, as such a high-density recording medium, various types of recording media, such as a recording medium capable of only reproducing recorded information, a recording medium capable of performing recording once, and a recording medium capable of performing recording multiple times, are also available. A medium has been proposed. Note that these various recording media have different characteristics, particularly in terms of the reflectance and the like.

On the other hand, in a recording / reproducing apparatus for an optical information recording medium for reproducing recorded information from a high-density recording medium in which uneven portions called land areas and groove areas are formed, a conventional optical reproduction method has been used. The control of the focus position of the means is performed by synchronizing with the address signal recorded in advance in an area formed between the land area and the groove area, that is, an area called a pit address area. Control has been performed by alternately switching between a focus position for an area and a focus position for a groove area.

[0005]

However, in such a high-density recording medium as described above, in order to accurately reproduce information recorded at a high density, an optical pickup as an optical reproducing means, particularly, an optical pickup, It is necessary to control the focus position of the focus lens more precisely. Normal,
In a recording / reproducing apparatus for an optical information recording medium, at the time of shipment, the focus position is adjusted so as to be controlled to a previously determined optimum position. However, for example, the type and state of the recording medium are controlled. Furthermore, it is important to adjust the focus position to an optimum position in conformity with the use environment of the device including the temperature and the like, and for that purpose, it is necessary to control the focus position based on the recorded information actually reproduced by the device. Correcting the focus position to the optimal position,
For example, the control is performed by employing a control employing a learning control or the like.

However, as described above, when the optical pickup is focused on only the focus position for information reproduction by focus position control such as learning control, and is controlled so as to be a more optimal position, however, This causes a problem in reproducing address information recorded in the pit address area formed between the land area and the groove area.

That is, as described above, the focus position of the optical pickup is controlled by alternately switching between the focus position for the land area and the focus position for the groove area while synchronizing with the address signal of the pit address area. That is being done. However, if the focus position of the optical pickup is controlled to an optimum position only for reproducing the recorded information in the land area or the groove area, the address information in the pit address area cannot be accurately read. Occurs.

However, when it becomes impossible to read the address signal in the pit address area accurately, such an apparatus performs various operations including information reproduction or recording by using the address information in the pit address area. Therefore, the operation of the entire recording / reproducing apparatus including the tracking control of the optical pickup cannot be guaranteed, so that the function as the recording / reproducing apparatus cannot be performed.

Accordingly, the present invention has been made in view of the above-mentioned prior art, and based on the above-mentioned recognition of the present inventors, in particular, an optical information recording apparatus in which information is recorded at a high density by forming land areas and groove areas. It is possible to optimally control the focus position of the optical pickup, which is the optical reproducing means, by reading out and reproducing the recorded information on the medium or recording the information on the medium. It is possible to reliably take in the address information of the pit address area between the area and the groove area, so that the recording / reproducing of the optical information recording medium which can perform the good reproduction or the recording operation under various conditions. It is an object of the present invention to propose a reproducing apparatus and a focus control method thereof.

[0010]

First, in order to achieve the above-mentioned object, according to the present invention, there is provided a land region, a groove region, and a structure formed between the land region and the groove region. Optical information recording medium for reading information recorded on the recording surface of an optical information recording medium having a pit address area and a pit address area while controlling a focus position of an optical reproducing means in accordance with the land area and the groove area, respectively. In the recording / reproducing apparatus, information is set by setting a focus position of the optical reproducing means in the land area and the groove area so as to always be located within a focus position area obtained in conformity with the pit address area. This is a focus control method in a recording / reproducing apparatus for an optical information recording medium for reading out information.

Further, according to the present invention, in the above-described focus control method for the optical information recording medium recording / reproducing apparatus, the focus position obtained in conformity with the pit address area is determined by setting the optical information recording medium to the optical information recording medium. This is determined and set when inserted into the information recording medium reproducing apparatus.

Further, according to the present invention, in the above-described focus control method for the recording / reproducing apparatus for an optical information recording medium, the focus position of the optical reproducing means is controlled in conformity with the land area and the groove area, respectively. As a method, learning control is adopted.

Further, according to the present invention, in the focus control method in the recording / reproducing apparatus for an optical information recording medium, the focus position of the optical reproducing means is controlled in accordance with the land area and the groove area, respectively. Therefore, by detecting the reflection intensity at a predetermined pattern formed at the head of each sector on the recording surface of the optical information recording medium,
The focus position is controlled based on the detected reflection intensity.

According to the present invention, in order to achieve the above object, an optical information device comprising a land area, a groove area, and a pit address area formed between the land area and the groove area. On the recording surface of the recording medium, while controlling the focus position of the optical reproducing means in accordance with the land area and the groove area, respectively, in a recording / reproducing apparatus of a recording optical information recording medium for recording information,
Optical information recording for recording the information by setting the focus position of the optical reproducing means in the land area and the groove area so as to always be located within a focus position area obtained in conformity with the pit address area. A focus control method for a medium recording / reproducing apparatus has been proposed.

[0015] In addition, according to the present invention, in order to achieve the above object, a land area, a groove area,
The information recorded on the recording surface of the optical information recording medium having a pit address area formed between the land area and the groove area is used to change the focus position of the optical reproducing means to the land area and the groove area. In the recording / reproducing apparatus of the optical information recording medium, which is set and read out respectively,
Further, the optical information recording medium may further include a control unit that sets a focus position of the optical reproducing unit in the land area and the groove area so as to be located within an area of a suitable focus position in the pit address area. A recording / playback device is proposed.

According to the present invention, in the recording / reproducing apparatus for an optical information recording medium described above, the control means includes means for optically recognizing information formed in the pit address area.

Further, according to the present invention, the above-described recording / reproducing apparatus for an optical information recording medium further comprises means for recording information on a recording surface of the optical information recording medium.

According to the present invention, in the recording / reproducing apparatus for an optical information recording medium, the information recording means adjusts a focus position of the optical reproducing means at the time of information recording in the pit address area. Control means for setting the focus position within the region of the focus position to be set.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, FIG. 2 of the accompanying drawings shows an optical information recording medium such as a DVD disk, which is a high-density recording medium for reproducing the recorded information by the optical information recording medium recording / reproducing apparatus according to the embodiment of the present invention. 100 is shown. Among such optical information recording media, in particular, in a recordable medium called a DVDRAM, information is formed by forming so-called pits in a recording layer in a transparent substrate by using, for example, a phase change caused by laser light irradiation. Can be written, and then
The recorded information is reproduced by the written pits. Alternatively, in a read-only optical information recording medium called a DVDROM, a recording surface on which information has already been written is irradiated with a laser beam, and the recorded information is reproduced by the reflected light.

The optical information recording medium 1 shown in FIG.
00 is, for example, a recordable medium called the DVDRAM, and as shown in the figure, a ROM section 110 in which predetermined control information and the like are recorded in the center thereof.
And a RAM unit 120 around it. In the high-density recording medium as described above, in particular, the R
In the AM section 120, a spiral track T for continuously recording information on a disk is used as the information recording portion.
At the same time, this track is formed in a so-called land area and groove area, which is an uneven area so as to increase the recording density of the track, thereby enabling information recording and reading.

FIG. 3 shows a cross section of the land area and the groove area of the information recording section. In this figure, the land area is indicated by the symbol L, while the groove area is indicated by G, and these land areas L and groove areas G are formed alternately in the radial direction of the disc-shaped recording medium 100. In addition, in the land area L and the groove area G, so-called pits are formed as shown by broken lines in the figure, and information is recorded.

FIG. 4 shows a format for forming the land area L and the groove area G in such a high-density recording medium.
Are indicated by hatched portions, while the groove region G is formed between these hatched portions. The land area L and the groove area G are formed alternately between the land area L and the groove area G in units of one circumference of the disk-shaped recording medium 100. Note that in this figure, the land area L and the groove area G are switched at the dashed line. In addition, these land areas L
And the groove area G are formed in units called 17 to 34 sectors in units of one circumference of the track T on the disk, and a pit address area P
It is partitioned by an area called A. The RAM section 120 in the disk is divided into zones from the inner circumference to the outer circumference. Each zone has the same number of sectors.

FIG. 5 shows a pit address area formed between the land area L and the groove area G. First, FIG. 5A shows a portion (pit address area indicated by a dashed line in FIG. 4) that transitions from the land area L to the groove area G, and a laser beam for detecting a recording signal. As shown by a dashed-dotted arrow in the figure, for example, a transition is made from the land area L to the groove area G through the pit address area PA.

On the other hand, FIG. 5 (B) shows a transition from the land area L to the land area L. Also in this case, a laser beam for detecting a recording signal is indicated by a dashed line arrow in the figure. As shown by, for example, a transition is made from the land area L to the next land area L through the pit address area PA. It is needless to say that, when a transition from the groove area G to the next groove area G is made, the pit address area PA is passed, similarly to the above.

As described above, in the recording medium 100 for recording the recording information at a high density, the recording information is recorded alternately in the land areas L and the groove areas G having different heights. In order to reliably reproduce information, an optical pickup, which is an optical reproducing unit that reproduces recorded information using reflection of laser light for each of the land area L and the groove area G having different heights, In particular, it is necessary to optimally control the focus position of an optical lens (focus lens) for converging and irradiating a laser beam for reproduction onto the recording medium surface.

At the same time, the pit address area P
As is clear from the figure, FIG.
The upper address number is determined by a plurality of pit strings P, P.
Recorded on both sides. Therefore, in order to reproduce the record information from the recording medium 100, the plurality of pits P, P.
Must be detected accurately.

Therefore, the present invention employs so-called learning control in order to optimally control the focus position of the optical lens in the optical reproducing means in reproducing the recorded information from the high-density recording medium 100. Optimum position control and the pit address area PA
Recording of an optical information recording medium, which can reliably detect the pits P, P...
A playback device is provided.

First, the overall configuration of a recording / reproducing apparatus for an optical information recording medium according to an embodiment of the present invention is shown in FIG. In this figure, reference numeral 100 denotes
Similarly to the above, a high-density recording medium is shown.
Numeral 0 passes through a semiconductor laser 210 which is a light emitting element for generating laser light of a desired wavelength, an optical lens 220 for condensing emitted laser light into parallel light, and a part of incident light. And a mirror 240 for changing the direction of light, and a focus lens 25 for irradiating the recording surface of the high-density recording medium 100 with a laser beam converged to a predetermined beam diameter.
0, an optical pickup which is an optical reproducing means including a light receiving element 260 for receiving and detecting the reflected light from the half mirror 230.

Further, in FIG.
Is a signal processing section for detecting light by the light receiving element 260 of the optical reproducing means, converting reflected light into an electric signal, and performing predetermined processing. The signal processing section 300 is an optical information recording medium reproducing apparatus. Is connected to a microcomputer 400 provided for performing overall control of the camera, and thereby includes a focus control method described in detail below.
Various controls are performed. That is, the microcomputer 400 is further connected to a laser drive circuit 500, a feed control circuit 600, a spindle control circuit 700, and a two-dimensional actuator control circuit 800.

That is, with the above-described configuration, the microcomputer 400 is a semiconductor laser 210 which is a light emitting element of the optical pickup 200 which is the optical reproducing means.
The current supplied to the optical reproducing unit 200 is controlled by controlling the emission intensity by controlling the current supplied to the optical reproducing unit 200 and controlling the rotation of the motor 650 for feed control.
Control the position in the 0 radial direction. Reference numeral 660 in the figure is
A gear for moving the optical pickup 200 in the radial direction by rotation of the feed control motor 650.

The microcomputer 400 controls the rotation of a motor 750 for driving the spindle to rotate, thereby controlling the linear velocity (LVC), which is a constant linear velocity control widely used in such high-density information recording media. Velocity) or ZCLVC (zoned constant linear velocity). In particular, in the latter ZCLVC, the rotation speed (angular velocity) is controlled to be constant within each zone, and the rotation speed is changed for each zone. Further, this microcomputer 40
Reference numeral 0 indicates that the two-dimensional actuator control circuit 800 controls the focus position of the focus lens 250 of the optical pickup 200 by electromagnetic action using, for example, an electromagnetic coil 850 or the like as its operating means. The two-dimensional position control of the focus realized by the two-dimensional actuator control circuit 800 is, in addition to the position control of the focus lens 250 in the direction perpendicular to the recording surface of the high-density recording medium 100, Further, tracking position control for following a track by minute position adjustment in a radial direction perpendicular to the above is included.

Next, FIG. 1 of the accompanying drawings shows a light receiving element 260 in an optical pickup 200 which is an optical reproducing means in the recording / reproducing apparatus for an optical information recording medium according to one embodiment of the present invention, The detailed configuration including the signal processing unit 300 that processes the detection signal and its peripheral parts is shown.

As is apparent from FIG.
60 is divided into four detection units A, B, C, and D, and the reflected light reflected on the recording surface of the high-density recording medium 100 and incident on the light receiving element 260 is Each is converted into an electric signal by the detection unit and output. Note that each of the divided detection units A, B, C, D
Are input to adders 301 to 304, and are respectively (A + C), (B + D), (A + D), (B +
C) is added. Further, the outputs from the adders 301 and 302 are input to the adder 305, whereby the sum of (A + B + C + D) obtained by adding all the outputs from the detection units A, B, C, and D is added. A signal is output.

The outputs from the addition circuits 301 and 302 are also input to a subtraction circuit 306 at the same time, so that the output thereof has a value ((A + C)-(B + D)) for tracking. , A tracking error signal TE is output. After that, the tracking error signal TE passes through a high frequency pass filter (HPF) 307 to obtain an ID signal. That is, the ID signal is obtained by reading the address number pits P, P... Generated in the pit address area PA shown in FIG. 6 as a signal waveform as shown in FIG. 7A, for example. is there. In addition,
The read ID signal is taken into the microcomputer 400 and recognized as an address number of each sector on a track on the recording surface of the high density recording medium 100.

On the other hand, the tracking error signal TE
At the same time, after passing through a low frequency pass filter (LPF) 308, the adder 309 adds the offset value from the D / A converter 310. For tracking control in the groove area, first, the polarity of the tracking error signal TE is inverted by an inverting circuit 312, and further output to the two-dimensional actuator control circuit 800 via the switch element 315. On the other hand, for tracking control in the land area, the signal is thereafter output to the two-dimensional actuator control circuit 800 via the switch element 318. However, one of the switch elements, that is, the switch element 318 that passes the tracking control signal in the land (L) region, has the L / G
The switching signal is input via the inverting circuit 319. That is, thereby, the tracking control signal in the land (L) area and the tracking control signal in the groove (G) area are alternately output to the two-dimensional actuator control circuit 800 based on the tracking signal TE. This output becomes a TR signal for controlling the tracking, and the feed control circuit 600 in FIG. 6 controls the position of the optical reproducing means 200 in the radial direction. The D / A converter 310 is provided with an offset value from the microcomputer 400 via the A / D converter. Here, since the relationship with the present invention is weak, a detailed description thereof will be omitted.

On the other hand, the signals (A + D) and (B + C) output from the addition circuits 303 and 304 are input to a subtraction circuit 311, whereby ((A + D) − (B +
The focus error signal FE represented by C)) is obtained. The focus error signal FE is processed by being divided into the focus control signal in the land area and the focus control signal in the groove area.
Thereafter, the focus position of the focus lens 250 of the optical reproducing means 200 (in the direction perpendicular to the recording surface of the high-density recording medium 100) is controlled via the two-dimensional actuator control circuit 800.

That is, the focus error signal FE ((A + D)-(B) which is the output from the subtraction circuit 311
+ C)) is applied with the focus offset by the adder 314, and is output to the two-dimensional actuator control circuit 800. The D / A 313 and the D / A 316 are used to set the groove and land offsets using the analog switch SW3.
17 is applied to the adder 314.

The D / A converters 313, 316
The microcomputer 400 provides an offset value for focus control in the groove area and the land area, respectively. A switching control signal output from the microcomputer 400, that is, a land (L) area / groove (G) area switching signal is also input to the control input of the switch element 317.

The offset value added to the focus error signal FE via the D / A converters 313 and 316 is employed in the present invention to control the focus position of the optical lens to an optimum position. It is a variable that is learned in the learning control, and when the optical information recording medium is shipped as a product of the recording / reproducing apparatus, the optical information recording medium is initially set to a predetermined value before being shipped. The initial set values are recorded in an EPROM or the like, which is recording means of the microcomputer 400.

Further, the sum signal (A + B + C + D) from the adder circuit 305 is then supplied to a high frequency pass filter (HPF) 320 and a low frequency pass filter (LPF) 3
The signal passes through the A / D converter of the microcomputer 400 through the envelope detection circuit 322 and the sample / hold (S / H) circuit 323. Note that this sample hold (S / H)
The timing captured by the circuit 323 is determined by a sample / hold (S / H) timing signal output from the microcomputer 400, as will be described later.

Next, a focus control method in the recording / reproducing apparatus for an optical information recording medium of the present invention described in detail above will be described with reference to the flowcharts of FIGS. First, the flowchart shown in FIG. 8 is performed before performing the learning control shown in FIG. 10 below, whereby the variable region of the focus position in the learning control is set in advance. This flow is started, for example, at the same time when the reproducing apparatus is turned on, is executed based on the various output signals shown in FIG. 1, and is executed for each of the land area and the groove area. .

In this flow, first, the offset of the focus error (FE) is set to an initial setting value (step S11). That is, the microcomputer 40
0 sets the initial setting values recorded in the EPROM or the like at the time of shipment in the D / A converters 313 and 316. Thereafter, the microcomputer 400 performs a plurality of steps (for example, +8 steps to) before and after the offset initial setting value around the initial setting value (0) as shown in FIG. -16 steps up to -8 steps), each step value is set as the offset value of the focus error (FE) to change the focus position, and the pit address area is changed at these plural focus positions. Judgment of pit reproduction at At this time, as a determination condition of the pit address reproduction, it is determined whether or not the ID signal shown in FIG. Alternatively, the number of sectors in which an ID signal can be recognized in one track may be used as the determination condition.

That is, in FIG. 8, first, the above-mentioned steps from 0 to -8 are sequentially set as the offset value (step S12), and the pits P in the pit address area PA are also set according to their respective focus positions. , P... Are recognized to determine whether the address can be reproduced (step S13). If the pit address can be reproduced ("OK") as a result, the offset value is stored (step S13). S14) This is repeated until it becomes impossible to reproduce the pit address ("NG").
Thereafter, in the same manner as above, the offset value is set to 0 to +8
The steps are sequentially set (step S15), playback is determined (step S16), a reproducible offset value is stored (step S17), and playback is not possible ("NO").
Finally, an offset value within a range that can be changed by learning, that is, a pit address recognizable value is set according to the step range (step S18), and the process ends.

As a result, a range in which the pits P, P... Of the pit address area PA can be reliably recognized can be set in -8 to +8 steps around the offset initial value (0) of the focus position control. become. Specifically, for example, in FIG. 9A, in the focus position control in the land area, since the step is “NG” at −8 and +5, the area between −7 and It can be seen that the pits P, P... Of the pit address area PA can be reliably recognized in the range of the step +4. Therefore, in the focus position control in the land area, if learning control is performed within the range of -7 to +4, the focus position can be controlled to a more optimal position while ensuring reproduction of the pit address. You can do it. Note that the same applies to the focus position control in the groove area, and in the example shown in FIG. 9B, learning control can be performed later within the range of -4 to +7 steps. You can see that.

Next, learning control for controlling the optimum focus position in the land area and the groove area where information is recorded will be described with reference to FIGS. When an unrecorded disk is inserted, the test zone and the laser drive circuit 500 assigned to the innermost and outermost circumferences of the disk are driven to perform recording. In this learning, since the relative change in the amplitude of the reproduced signal of the recorded data is detected,
For the recording pattern setting, a preset initial value is sufficient.

First, FIG. 10 shows a schematic processing flow of learning control for optimal focus position control. First, data is reproduced (step S21). At this time, as shown in FIG. 7A, a VFO section in which pits having a predetermined width, for example, called 4T, in which a predetermined pattern (number) is recorded is arranged at the head of each sector. After that, a data (DATA) portion in which recording information to be reproduced is recorded continues. And there, especially in order to control the optimal focus position,
This is performed by utilizing the intensity of the reflected light in the VFO section. That is, in the VFO section, the reproduced signal waveform is as shown in FIG. 7C, however, the envelope detection circuit 32 which outputs the envelope waveform is used.
2 (see FIG. 1), if the output as shown in FIG. 7 (D), that is, if the reflectance of the recording surface of the recording medium 100 is constant, the height (voltage) is always constant. Signal is output. The reason why the 4T pattern is adopted is as follows. In the phase change medium, the recording pattern is stable with respect to the fluctuation of the recording pattern, and the focus position of the optimum condition of recording and reproduction by the land-groove method is determined by the 4T pattern. It has been confirmed through experiments and the like that the maximum amplitude can be obtained.

Therefore, as apparent from FIG.
The microcomputer 400 outputs a sample hold (S / H) signal during the period of the VFO section, and detects and reproduces the height of the envelope waveform (FIG. 7D) from the sample hold (S / H) circuit 323. It is taken in as the signal amplitude value. At this time, sample hold (S / H)
The signals and the amplitude of the detected reproduction signal (detected reproduction signal amplitude), which is the height of the envelope waveform captured by the signal, are shown in FIGS. 7E and 7F.

Referring back to FIG. 10, in the learning control for the optimum focus position control, next, the offset of the focus error (FE) is set (step S2).
2). That is, here, the range is set by the pit address recognizable area obtained in step S18 in FIG. Specifically, for example, as shown in FIG. 9B, the possible setting area for the groove (G) area is -4 to +7, and this step value is set. .

Thereafter, as described above, based on the amplitude of the detected reproduction signal taken in from a plurality of sectors, the offset value (step) of the focus error (FE) at which the signal amplitude in each sector is maximized. Unit) is obtained (step S23). Then, the focus error (FE) offset value obtained for each sector is averaged by the following equation, and the optimum focus error (FE) offset for the land (L) area and the groove (G) area in the recording medium 100 is obtained. Value FEoff (L), FEof
f (G).

(Equation 1)

In the above, this is to eliminate non-uniformity (so-called variation) in the reflectance and the like in sector units in the circumferential direction of the disk as the recording medium 100.
That is, as shown in FIG. 11, for example, when the amplitudes of the detected and reproduced signals (see FIG. 7F) are different in each sector (Sec. 1 to Sec. 17), first, each sector In (2), the optimum FE offset value is obtained (specifically, the FE offset values of sectors extending over the same plurality of circumferences in the radial direction are averaged). Thereafter, the FE offset values of each sector are averaged to obtain optimum FE offset values FEoff (L) and FEoff (G). This is briefly described with reference to FIG. 12 attached hereto. For example, three sectors Sec. 1 to Sec. When the offset values at which the detected reproduced signal amplitude becomes maximum are determined to be -1, +1 and +3, respectively, these are averaged, and +1 (step unit) is determined as the optimum FE offset value. Become. As a method of calculating the focus offset value of the maximum amplitude value, a difference method, calculation of a maximum position by quadratic curve approximation calculation, and a left and right offset in which the amplitude value is reduced by -1 dB from the amplitude for which the substantially maximum value is obtained. For example, there is a method of obtaining the half value of the position.

At this time, as is clear from the above description, the optimum FE offset value obtained by the above control was set in the above-mentioned step S22 (−7 to −7).
If the value exceeds the step range of +4), the closest value among the set values, that is, -7 or +4 is selected as the optimum FE offset value.
In other words, this makes it possible to always control the focus position of the optical pickup to the optimum position while accurately reading the address signal in the pit address area, and the lack of address information impairs the operation of the entire reproducing apparatus. Without this, good focus control is always possible.

In the above description, so-called learning control has been described as an example of a method of controlling the optimal position of the focus, however, the present invention is not limited to such learning control. That is,
It is apparent that the present invention can be applied to the case where other control methods for performing the optimal position control of the focus are adopted in the same manner as described above.

Further, in the description of the above embodiment, a reproducing apparatus for reading information recorded in advance on the optical information recording medium 100 and its operation have been described. The present invention is not limited to the above-mentioned reproduction-only reproducing apparatus, and can be applied to a recording / reproducing apparatus for an optical information recording medium having a function of writing information. When the present invention is applied to such a recording / reproducing apparatus for an optical information recording medium, it is used not only at the time of information reproduction, but also in the focus control at the time of information recording, in the same manner as described above. It is possible to apply. And also in that case, since the address information on the recording surface of the optical information recording medium at the time of recording can be reliably obtained,
It will be apparent from the above description that a more optimal information recording operation can be obtained.

[0054]

As is apparent from the above detailed description, according to the recording / reproducing apparatus for an optical information recording medium and the focus control method according to the present invention, in particular, the land area and the groove are formed on the information recording surface. In the information reproduction or recording of a high-density optical information recording medium such as a DVD in an area, the focus position of an optical pickup serving as an optical reproducing means can be optimally controlled to ensure good information reproduction or recording operation. In addition, by always ensuring that the address information of the pit address area between these areas, which is the basis of the operation of such a device, can be reliably taken, even under various conditions, good reproduction or recording is always achieved. An extremely excellent effect of enabling operation is exhibited.

[Brief description of the drawings]

FIG. 1 is a detailed diagram of a circuit configuration centering on a signal processing unit for processing a detection signal from a light receiving element of a recording / reproducing apparatus for an optical information recording medium according to an embodiment of the present invention.

FIG. 2 is a high-density recording medium D on which information is reproduced / recorded by the optical information recording medium recording / reproducing apparatus of the present invention.
FIG. 4 is a perspective view illustrating an appearance of a VD.

FIG. 3 is a sectional view of a land area and a groove area of an information recording section in the DVD shown in FIG. 2;

FIG. 4 is an explanatory diagram showing a formation format of a land area and a groove area in the DVD as the high-density optical recording medium.

FIG. 5 is a partially enlarged perspective view showing a pit address area formed between a land area and a groove area in the DVD.

FIG. 6 is a block diagram showing an overall configuration of a recording / reproducing apparatus for an optical information recording medium according to the present invention.

FIG. 7 is a waveform chart showing signal waveforms at various parts in the optical information recording medium recording / reproducing apparatus of the present invention.

FIG. 8 is a flowchart illustrating a focus control method in the optical information recording medium recording / reproducing apparatus of the present invention.

FIG. 9 is an explanatory diagram specifically explaining a pit address recognizable area set by the focus control method shown in FIG. 8;

FIG. 10 is a flowchart for explaining learning control of focus control in the optical information recording medium recording / reproducing apparatus of the present invention.

FIG. 11 is an explanatory diagram illustrating an optimal FE offset value of each sector set by the learning control of FIG. 10;

FIG. 12 is an explanatory diagram for simply explaining an optimum FE offset value set by averaging in the learning control of FIG. 10;

[Explanation of symbols]

 Reference Signs List 100 high-density optical recording medium (DVD) L land area G groove area PA pit address area P pit 200 optical reproducing means (optical pickup) 250 focus lens 300 signal processing unit 400 microcomputer 800 two-dimensional actuator control circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshimitsu Kaku 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within the Visual Information Media Division of Hitachi, Ltd. (72) Kazuo Shigematsu 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. Video and Information Media Division (72) Inventor Shinichi Arai 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd. Video and Information Media Division (72) Inventor Koichiro Wakabayashi 1-280 Higashi Koigakubo, Kokubunji, Tokyo Address Co., Ltd., Central Research Laboratory, Hitachi, Ltd.

Claims (9)

[Claims] 1. An optical information recording medium comprising: a land area; a groove area; and a pit address area formed between the land area and the groove area. In a recording / reproducing apparatus of an optical information recording medium for reading while controlling the focus position of the optical reproduction means in conformity with the land area and the groove area, the focus position of the optical reproduction means in the land area and the groove area is A focus control method in a recording / reproducing apparatus for an optical information recording medium, wherein information is read out while always being set to be within a focus position area obtained in conformity with the pit address area. 2. The focus control method for a recording / reproducing apparatus for an optical information recording medium according to claim 1, wherein a focus position obtained in conformity with the pit address area is determined by using the optical information recording medium as the optical information recording medium. A focus control method in a recording / reproducing apparatus for an optical information recording medium, wherein the focus control method is obtained and set when inserted into a recording medium reproducing apparatus. 3. A focus control method for a recording / reproducing apparatus for an optical information recording medium according to claim 1, wherein the focus position of said optical reproducing means is controlled in accordance with the land area and the groove area, respectively. A focus control method in a recording / reproducing apparatus for an optical information recording medium, wherein learning control is adopted. 4. A focus control method in a recording / reproducing apparatus for an optical information recording medium according to claim 1, wherein a focus position of said optical reproducing means is controlled in accordance with said land area and said groove area, respectively. Detecting the reflection intensity in a predetermined pattern formed at the head of each sector on the recording surface of the optical information recording medium,
A focus control method in a recording / reproducing apparatus for an optical information recording medium, wherein a focus position is controlled based on the detected reflection intensity. 5. On a recording surface of an optical information recording medium comprising a land area, a groove area, and a pit address area formed between the land area and the groove area.
In a recording / reproducing apparatus of a recording optical information recording medium for recording information while controlling a focus position of an optical reproducing unit so as to be adapted to the land area and the groove area, the optical reproduction in the land area and the groove area is performed. A recording / reproducing apparatus for an optical information recording medium, wherein the information is recorded by setting a focus position of the means so as to always be located within an area of a focus position obtained in conformity with the pit address area. Focus control method. 6. An optical information recording medium comprising: a land area, a groove area, and a pit address area formed between the land area and the groove area. In the recording / reproducing apparatus for an optical information recording medium, wherein the focus position of the optical reproducing means is set and read in the land area and the groove area, the focus position of the optical reproducing means in the land area and the groove area is further A recording / reproducing apparatus for an optical information recording medium, comprising: a control means for setting a position in a pit address area so as to be located within a suitable focus position area. 7. The recording / reproducing apparatus for an optical information recording medium according to claim 6, wherein said control means includes means for optically recognizing information formed in said pit address area. Characteristic recording / reproducing apparatus for optical information recording media. 8. The recording / reproducing apparatus for an optical information recording medium according to claim 6, further comprising means for recording information on a recording surface of the optical information recording medium. Recording / reproducing apparatus for optical information recording media. 9. The recording / reproducing apparatus for an optical information recording medium according to claim 8, wherein said information recording means adjusts a focus position of said optical reproducing means at the time of information recording in said pit address area. Recording / recording of an optical information recording medium, characterized by comprising control means for setting the position to be located inside the focus position area.
Playback device.