JPH05266499A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide an optical recording and reproducing device performing the servo of tracking, etc., stably to an optical recording medium with the different medium constitution of a track pitch, etc., and recording, reproducing or erasing to various kinds of high density optical recording mediums. CONSTITUTION:The standard track area of the optical recording medium 10 is reproduced by a standard servo condition, and the tracking servo gain of a lens driving part 62 and the servo conditions of a track jump condition, etc., are switched to an optimum value according to the track pitch of a user area by a servo condition switching part 70 based on a user area servo condition read by a signal regeneration part 58. Thus, stable recording, reproducing and erasing are performed in the user area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus for recording, reproducing, or erasing information by laser light, and more specifically, it is stable for optical recording media having different structures such as track pitch. The present invention relates to an optical recording / reproducing device capable of recording, reproducing and erasing.

[0002]

2. Description of the Related Art Conventionally, an optical recording / reproducing apparatus for recording, reproducing, or erasing information on an optical recording medium by using a laser beam has an optical recording medium 1 as shown in a schematic block diagram of FIG.
01 is irradiated with laser light to receive reflected light from the optical recording medium 101, a laser driving unit 104 for driving a laser that is a light source of the optical head 102, and reflected light received by the optical head 102. A servo signal reproducing unit 106 that reproduces a servo signal and an information signal, an information signal reproducing unit 107, and an actuator 110 that moves a condenser lens 108 that condenses laser light on an optical recording medium 101 that is rotating by a spindle motor (not shown). The lens drive unit 112 is controlled so that the light spot that is driven and focused can always follow a predetermined track. Further, a control unit 114 that outputs recording data and controls the positions of the spindle motor and the optical head 102, etc.
And a modulation unit 116 that performs, for example, 2-7 rate modulation on the recording data output from the control unit 114.

The servo signal generator 106 is an optical head 10.
A focus error (focusing error) and a tracking error (trace error with respect to a track) are detected from the light reception output output from 2 to generate a focus error signal and a tracking error signal. The lens drive unit 112 drives the actuator 110 with a predetermined focus servo gain and tracking servo gain based on the servo signal output from the servo signal generation unit 106, that is, the focus error signal and the tracking error signal, and the condenser lens 108. Move in the focus and tracking directions. When performing a track jump for only one track, first, the lens driving unit 1
A jump pulse 120 as shown in FIG. 12 is output from 12 to move the condenser lens 108 in the radial direction of the optical recording medium 101 in a direction to forcibly jump. next,
The brake pulse 121 is output so that the laser spot does not move too much over the adjacent track, and after jumping one track, the movement of the condenser lens 108 is stopped.

The optical recording medium 101 is usually provided with guide grooves with a track pitch of 1.6 μm, and tracking is performed by a well-known push-pull method using the guide grooves. Then, in the conventional optical recording / reproducing apparatus, servo conditions such as focus servo gain and tracking servo gain in the lens drive unit 112 are set so that optimum servo can be performed in accordance with such a specific track pitch. Has been done.

[0005]

However, if the track pitch of the optical recording medium 101 is made narrower than the conventional 1.6 μm in order to increase the recording density, the push-pull signal strength used for tracking decreases, and therefore the conventional In an optical recording / reproducing apparatus, when recording / reproducing is performed on an optical recording medium having a narrow track pitch, the tracking servo gain becomes insufficient. As a result, the tracking error increases, and there is a problem that the track cannot be tracked and tracking becomes impossible. Further, since the jump pulse becomes too large, the laser spot moves too much over the adjacent track, which makes it impossible to perform a normal track jump.

On the contrary, for example, when the tracking servo gain and the like are increased so that the optimum servo can be performed on the optical recording medium having a narrow track pitch, and the magnitudes of the jump pulse and the brake pulse are decreased. Since the tracking servo gain becomes excessive with respect to the conventional optical recording medium having a wide track pitch, the tracking servo loop oscillates, which causes the actuator 110 to run away and damage the condenser lens 108 and the like in the worst case. There is a problem that the jump pulse becomes too small to move the laser spot to the adjacent track, and the track jump cannot be executed.

As described above, the same optical recording / reproducing apparatus records on optical recording media having different track pitches,
Since reproduction or erasure could not be performed, the compatibility between optical recording media was significantly impaired.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a servo condition switching means for switching the servo condition of the lens driving section according to the optical recording medium. By this, servo such as tracking can be stably performed on optical recording media having different medium configurations such as track pitches, and recording, reproduction, or erasing can be performed on various high-density optical recording media. An object is to provide an optical recording / reproducing device.

[0009]

To achieve this object, in an optical recording / reproducing apparatus of the present invention, an optical recording medium is irradiated with laser light through a condenser lens and at the same time receives reflected light from the optical recording medium. A head, a signal reproducing section that outputs a servo signal and an information signal based on the reflected light from the optical recording medium received by the optical head, and a lens driving section that drives a focusing lens of the optical head based on the servo signal. An optical recording / reproducing apparatus including: a servo condition switching means for switching a servo condition such as a tracking servo gain of a lens driving unit and a track jump condition. Further, the servo condition may be switched based on the information signal read from a predetermined track of the optical recording medium using a preset servo condition.

[0010]

In the optical recording / reproducing apparatus having the above structure, the optical recording medium is irradiated with the laser beam through the condenser lens provided in the optical head, and the reflected light from the optical recording medium is received again by the optical head. A servo signal and an information signal are output from the signal reproducing unit based on the received reflected light. Based on this servo signal, the lens drive unit
The condenser lens is driven. At this time, the servo conditions are switched by the servo condition switching means according to the optical recording medium, so that the condenser lens can be driven under the optimum servo conditions for the medium configuration of each optical recording medium, and stable recording, reproduction, or It can be erased.

Here, the predetermined track of the optical recording medium is
It is formed with a standard track pitch that is common to all optical recording media. In this standard track area, reproduction is performed in advance in areas other than the standard track area, that is, in user areas where the medium configuration such as the track pitch differs depending on the optical recording medium. Alternatively, when the information required for recording / reproducing or recording / reproducing / erasing is recorded, the information is reproduced from the standard track area by using the preset common servo condition, and the tracking is performed based on this. Servo conditions such as servo gain and track jump conditions may be set to optimum values for each optical recording medium.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The optical recording / reproducing apparatus to which the present invention is preferably applied irradiates the optical recording medium 10 with laser light and reflects light from the optical recording medium 10 as shown in the main part of the block diagram of FIG. An optical head 52 that receives light, a laser drive unit 54 that drives a laser that is a light source of the optical head 52, a servo signal reproduction unit 56 that reproduces a servo signal and an information signal from the reflected light received by the optical head 52, and an information signal reproduction. The signal reproducing unit 58 including the unit 57 and the actuator 61 that moves the condenser lens 60 that condenses the laser light on the optical recording medium 10 are driven to control so that the condensed light spot always follows a predetermined track. And a lens driving unit 62 that operates.

Further, a control section 64 for outputting recording data and controlling other parts, a modulating section 66 for modulating the recording data output from the control section 64, and an information signal reproducing section 57 for reproducing. A demodulation unit 68 that demodulates the information signal into data and a servo condition switching unit 70 that switches the servo condition of the lens driving unit 62 according to the signal from the control unit.

The servo condition switching section 70 is provided with D / A conversion sections 72 and 73 and amplifiers 74 and 75 for converting a digital signal output from the control section 64 into an analog signal as shown in FIG. In addition, the lens driving unit 62
Includes a tracking servo AGC unit 76 that adjusts the servo gain so that the tracking error signal is constant with respect to variations in the amount of reflected light, and a jump signal generation unit 78 that generates jump pulses and brake pulses. Here, the tracking servo AGC section 76 is composed of an analog divider, a multiplier or the like whose gain changes proportionally according to the control voltage. For example, the output of the amplifier 74 is used as a control voltage in the tracking servo AGC section 76. By inputting, the magnitude of the tracking servo gain can be controlled by the digital signal from the control unit 64. Further, the jump signal generator 78 generates a jump pulse and a brake pulse having a magnitude corresponding to the output voltage of the amplifier 75.

In the optical recording medium 10, for example, as shown in the top view of FIG. 3, the standard track area 22 and the user area 24 in which the track pitches of the tracks 12 and 14 are different from each other.
Are formed. The standard track area 22 is, for example,
A plurality of tracks 12 provided on the optical recording medium 10,
It is formed with a track pitch of 1.6 μm on the innermost peripheral side of 14. The track pitch of the user area 24 is narrower than that of the standard track area 22 and is, for example, 1.0 μm.

As shown in FIG. 4, such an optical recording medium 10 has, for example, a guide layer 32 and an interference layer 3 on a substrate 30.
4, the recording layer 36, and the protective layer 38 are laminated, and a part of the guide layer 32 is in the standard track area 22 and the user area 24, for example, as shown in FIG. Have been removed by. That is, in the standard track area 22, track 1
The portion removed along a predetermined pattern along 2 forms a mark 40 indicating information necessary for recording, reproducing, and erasing in the user area 24.

On the other hand, the user area 24 is, for example, divided into several sectors 42 in the circumferential direction, and the index portion 44 at the start portion of the sector 42 is formed by the removed portion of the guide layer 32 along the track 14. A mark 45 for generating a preformat signal such as a mark is formed. In the remaining data area 46, a recording area 47 is formed in which the guide layer 32 is continuously removed along the track 14 by a predetermined length. Data is recorded on the recording layer 36 through the recording area 47. The thickness of the interference layer 34 is λ / (8n ′) or λ / (6n ′) so that a push-pull signal and a preformatted signal can be obtained.
It is chosen to the extent. Note that n'is the refractive index of the interference layer 34,
λ is the laser wavelength.

A resin such as acrylic or polycarbonate, or glass is used for the transparent substrate 30. The guide layer 32 is made of a metal such as Ta, Cr, or Al, and the recording layer 36 is a magneto-optical recording medium. For example, a rare earth transition metal amorphous alloy such as TbFeCo, TbFe, GdTbFe, or an extremely thin film of Pt and Co. A superlattice thin film having a multi-layered structure is used. Also,
The interference layer 34 and the protective layer 38 are made of glass, transparent oxides such as SiO2, AlN, SiN, or nitrides. The protective layer 38 functions to protect the recording layer 36 from oxidation and the like.

In general, when the track pitch becomes narrow, the push-pull signal strength used for tracking decreases. Therefore, in order to perform stable tracking, it is necessary to increase the tracking servo gain and correct the decrease in push-pull signal strength. Further, the movement amount when jumping to the adjacent track may be smaller as the track pitch is narrower, so that it is necessary to reduce the intensity of the jump pulse and the brake pulse. As described above, it is necessary to set the servo conditions such as the tracking servo gain and the track jump condition to optimal values according to the medium configuration such as the track pitch of the user area 24 of each optical recording medium 10. Therefore, the standard track area 2 of the optical recording medium 10 is
Information such as the track pitch of the user area 24 or servo conditions for the user area 24 is recorded in advance in the area 2.

A procedure of recording, reproducing, or erasing on such an optical recording medium 10 by the optical recording / reproducing apparatus of the present invention will be described with reference to the flowchart of FIG.

At the start of control, first, the optical head 52 is moved so that the standard track area 22 of the optical recording medium 10 is irradiated with the light emitted from the condenser lens 60. Next, standard servo condition data such as a tracking servo gain and a track jump condition which are stored or set in advance in the control unit 64 of the optical recording / reproducing apparatus are output from the control unit 64 to the servo condition switching unit 70.

The standard servo condition data is the D / A conversion unit 7.
After being converted into an analog signal by 2 and 73, the tracking servo gain is output from the amplifier 74 and is applied to the tracking servo AGC unit 76, and the tracking servo gain is applied from the amplifier 75 to the jump signal generating unit 78. The output sets the magnitude of the jump and brake pulses. After setting the standard servo conditions in this way, when the servo is turned on, the lens driving unit 62 drives the condenser lens 60 to optimally perform servo such as tracking. Here, in the optical recording medium 10 in which the track pitches of the user area 24 are different from each other, the standard track area 2
Since the track pitches of 2 are common, standard servo conditions are also common, and servo can be applied under the same conditions. In this state, the signal recorded in the standard track area 22 is reproduced by the information signal reproducing section 57 and demodulated by the demodulating section 68 to read the user area servo condition and the like for the user area 24 and to the control section 64. Remembered.

Here, the tracking servo is turned off once,
The optical head 52 is moved to the user area 24. In this user area 24, the user area servo condition data is output from the control unit 64 to the servo condition switching unit 70. In the same manner as when setting the standard servo condition, the user area servo condition data is converted into an analog signal by the D / A conversion units 72 and 73, and is passed to the tracking servo AGC unit 76 and the jump signal generation unit 78 through the amplifiers 74 and 75. Applied, tracking servo gain and jump pulse,
The magnitude of the brake pulse is set.

That is, since the track pitch in the user area is narrower than that in the standard track area 22, the tracking servo gain is set larger and the magnitudes of the jump pulse and the brake pulse are set smaller than in the standard servo condition. In this way, after setting the servo condition to the optimum value for the user area 24, the servo is turned on. As a result, the lens driving unit 62 causes the condenser lens 6
0 is driven, servo such as tracking is optimally performed, and recording, reproduction, or erasing can be stably performed in the user area. That is, in the same optical recording / reproducing apparatus, recording, reproduction, and erasing can be performed on the optical recording media 10 having different track pitches in the user area 24.

Although one embodiment of the present invention has been described in detail above with reference to FIGS. 1 to 6, the present invention can be implemented in other modes.

For example, the configuration of the servo condition switching section 70 is not limited to the embodiment shown in FIG. For example, as shown in FIG. 7, a plurality of tracking servo gain values G ₁ , G ₂ , G ₃ and the like, jump pulse and brake pulse magnitudes J ₁ , J ₂ , J _{3 and the} like are prepared in advance for control. Part 6
It is also possible to switch to a required value in the switching units 80 and 81 in accordance with the signal from 4. That is, since the track pitch of the high-density optical recording medium 10 is set to a specific value such as 1.4, 1.2, and 1.0 μm, by preparing only the servo conditions corresponding to these, the servo condition switching unit 70 The configuration is simple. In addition, the resistance value or the like that determines the tracking servo gain may be directly switched without passing through the amplifiers 74 and 75, and the servo condition switching means is not particularly limited.

Although the magnitudes of the jump pulse and the brake pulse are switched under the track jump condition, the present invention is not limited to this. For example, assuming that the pulse size is constant, as shown in FIG. 8A, the pulse width is wide when the track pitch is wide, and the pulse width is narrow when the track pitch is narrow as shown in FIG. 8B. You may switch so that width may become narrow. Further, the magnitude and width of the pulse are constant, and as shown in FIG.
When the track pitch is wide, the pulse number may be increased, and when the track pitch is narrow, the pulse number may be decreased as shown in FIG. The pulse width and the number of pulses can be easily controlled by the pulse circuit, and the A / D conversion unit is not required, so that the configuration of the servo condition switching unit 70 is simplified. Also, the absolute value of the magnitude of the jump pulse and the brake pulse, the pulse width, and the number of pulses do not have to be the same.

The servo condition is not limited to the tracking servo gain and the track jump condition, but may be the focus servo gain, the focus position, or the like, and is not particularly limited. For example, when the track pitch is narrowed, crosstalk is significantly increased due to an increase in the laser spot diameter on the optical recording medium 10 due to a focus shift. To avoid this, the focus servo gain may be changed according to the track pitch. That is, the focus servo gain may be increased for the optical recording medium 10 having a narrow track pitch. Further, the focus position may be changed according to the film thickness of the interference layer 34 and the like. Thereby, the laser can be always focused on the recording layer 36 even if the distance between the surface of the substrate 30 and the recording layer 36 changes depending on the thickness of the interference layer 34.

The information recorded in the standard track area 22 of the optical recording medium 10 is also not particularly limited. For example, part or all of the track pitch, the tracking servo gain, the magnitude of the jump pulse, etc. may be directly recorded, or they may be coded and recorded. That is, when only the track pitch is recorded in the standard track area 22, servo conditions such as a tracking servo gain corresponding to the track pitch are stored in the control unit 64 in advance, and the standard track area 22 is recorded.
The servo condition corresponding to the track pitch read from the control unit 64 may be output. Further, information other than the servo condition may be recorded, and the recording, reproducing, and erasing conditions for the user area may be set based on this information.

For the optical recording medium 10 in which the standard track areas 22 are formed in concentric circles, the same content is recorded in each track, so that the standard track can be recorded even if the servo is slightly unstable. Only one of the tracks formed in the area 22 can be reproduced, and the reproduction range under the standard servo condition becomes wide. Further, since there is no need for a track jump in the standard track area 22, the structure of the optical recording / reproducing device is simplified. Further, even if the reproduction is continuously performed, the area other than the standard track area is not reproduced, and the malfunction can be prevented.

Although FIG. 1 shows an embodiment in which the servo conditions are switched according to the track pitch, other constitutional conditions such as the film thickness of the interference layer 34 and the reflectance of the optical recording medium 10 described above are used. It may be switched according to need, and is not particularly limited. For example, for an optical recording medium having a partially different reflectance, the higher the reflectance is, the larger the tracking error signal or the like is. Therefore, the tracking servo gain may be switched to be smaller. At this time, if the track pitch is constant, it is not necessary to switch the track jump condition. Further, it may be switched depending on the substrate material.
That is, when glass is used for the substrate 30, warpage or the like is smaller than that when resin such as polycarbonate is used, so that even if the servo gain is switched to a high value, runaway does not occur, and the followability is improved. You can

Further, the operation procedure of the optical recording / reproducing apparatus of the present invention is not limited to the procedure described based on the flowchart of FIG. 6, and various modifications can be made. For example,
The servo condition may be switched to the user region servo condition before or during the movement of the optical head 52 to the user region 24. Further, with respect to an optical recording medium having no standard track, servo conditions may be sequentially switched to perform recording and reproduction, and the condition in which the operation is most stable may be set.

Further, the optical recording medium 10 is not limited to the one shown in FIGS. 3 and 4, and various types of optical recording media can be used. For example, the material and film thickness of each layer are not particularly limited, and TbFeCo is used as the recording layer 36.
Other than rare-earth transition metal alloys, multilayer films of PtCo and PdCo, oxide magnetic materials such as rare-earth iron garnet, and magneto-optical materials combining these, phase-change materials such as TeO _x and GeSbTe, holes such as Te A post-shaped material, an organic material such as a pigment, or the like may be used. Further, the pattern of the guide layer 32, the position of the standard track, the track pitch of the standard track region and the user region, etc. are not particularly limited. Here, if the standard track is formed at a common position in each optical recording medium, the optical head can be easily moved to the standard track in the optical recording / reproducing apparatus.

Even if the interference layer 87, the recording layer 88, and the protective layer 89 are laminated on the substrate 86 having the guide groove 85 as shown in FIG. 10, the same optical recording is performed. In the reproducing apparatus, recording, reproducing and erasing can be performed even when the track pitches of the user area 24 are different.

Further, the optical recording / reproducing apparatus of the present invention does not have to perform all the recording, reproducing and erasing, and for example, only reproducing or recording and reproducing may be performed.

The optical recording medium used in the optical recording system of the present invention does not have to be disk-shaped, and its shape is not particularly limited. For example, it may be card-shaped.

[0038]

As is clear from the above description,
The optical recording / reproducing apparatus of the present invention is provided with the servo condition switching means for switching the servo condition such as the tracking servo gain of the lens driving unit and the track jump condition according to the optical recording medium, and thus the medium structure such as the track pitch is formed. Servo such as tracking can be stably performed on different optical recording media, and recording, reproduction, or erasing can be performed on various high-density optical recording media.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an optical recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram showing main parts of a servo condition switching unit and a lens driving unit.

FIG. 3 is a main part plan view showing an example of an optical recording medium used in the optical recording / reproducing apparatus of the present invention.

FIG. 4 is a cross-sectional view of essential parts showing an example of an optical recording medium used in the optical recording / reproducing apparatus of the present invention.

FIG. 5 is a plan view of relevant parts showing a pattern formed on a guide layer of an optical recording medium used in the optical recording / reproducing apparatus of the present invention.

FIG. 6 is a flowchart showing an operation procedure of the optical recording / reproducing apparatus of the present invention.

FIG. 7 is a block diagram showing main parts of a servo condition switching section and a lens driving section in another embodiment of the optical recording / reproducing apparatus of the present invention.

8A and 8B are explanatory diagrams showing jump pulse and brake pulse waveforms in another embodiment of the optical recording / reproducing apparatus of the present invention.

9A and 9B are explanatory diagrams showing jump pulse and brake pulse waveforms in another embodiment of the optical recording / reproducing apparatus of the present invention.

FIG. 10 is a cross-sectional view of essential parts showing another example of the optical recording medium used in the optical recording / reproducing apparatus of the present invention.

FIG. 11 is a block diagram showing a configuration of a conventional optical recording / reproducing apparatus.

FIG. 12 is an explanatory diagram showing waveforms of jump pulses and brake pulses in a conventional optical recording / reproducing device.

[Explanation of symbols]

 10 optical recording medium 52 optical head 58 signal reproducing unit 60 condenser lens 62 lens driving unit 70 servo condition switching unit (servo condition switching means)

Claims (3)

[Claims] 1. An optical head for irradiating an optical recording medium with laser light through a condenser lens and receiving reflected light from the optical recording medium, and the reflected light from the optical recording medium received by the optical head. An optical recording / reproducing apparatus including a signal reproducing section that outputs a servo signal and an information signal based on the above, and a lens driving section that drives the condensing lens of the optical head based on the servo signal. An optical recording / reproducing apparatus comprising a servo condition switching means for switching servo conditions. 2. The optical recording / reproducing apparatus according to claim 1, wherein the servo condition is switched based on an information signal read from a predetermined track of the optical recording medium using a preset servo condition. Characteristic optical recording / reproducing device. 3. The optical recording / reproducing apparatus according to claim 1, wherein the servo conditions are a tracking servo gain and a track jump condition.