JPH05266498A - 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 a different track pitch and recording, reproducing or erasing to various kinds of high density optical recording mediums. CONSTITUTION:A sweep signal is outputted from a track pitch detection part 32 and a condenser lens 20 is moved by a prescribed distance in the radial direction of the optical recording medium 10. A traverse signal generated in accordance with movement is counted by the track pitch detection part 32 and a track pitch is detected and stable recording, reproducing and erasing are performed by switching the tracking servo gain of a lens driving part 22 and the servo conditions of a track jump condition, etc., to an optimum value according to the track pitch.

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 a laser beam, more specifically, stable recording on an optical recording medium having a different track pitch, The present invention relates to an optical recording / reproducing device capable of 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 a laser beam is
As shown in the schematic block diagram of FIG. 17, an optical head 102 for irradiating the optical recording medium 101 with laser light and receiving reflected light from the optical recording medium 101, and an optical head 102.
A laser driving unit 104 for driving a laser which is a light source of the optical disc, a servo signal reproducing unit 106 for reproducing a servo signal and an information signal from the reflected light received by the optical head 102, an information signal reproducing unit 107, and a spindle motor (not shown) for rotation. A lens driving unit 112 that drives an actuator 110 that moves a condenser lens 108 that condenses laser light on the optical recording medium 101, and controls so that the condensed light spot always follows a predetermined track. Is equipped with. Further, the control unit 1 that controls the output of recording data, the rotation of the spindle motor, the position of the optical head 102, and the like.
14 and a modulator 116 for performing, for example, 2-7 rate modulation on the recording data output from the controller 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 112 outputs a jump pulse 120 as shown in FIG.
Are forcibly moved in the radial direction of the optical recording medium 101 in a jumping direction. Next, a brake pulse 121 is output so that the laser spot does not move too much over the adjacent track, and after jumping only one track,
The movement of the condenser lens 108 is stopped.

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

[0006]

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, if 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 track pitch detecting means and a servo condition switching means in accordance with the track pitch of an optical recording medium. By switching the tracking servo gain and the like, servo such as tracking can be stably performed on optical recording media having different track pitches, and recording, reproduction, or erasing can be performed on various high-density optical recording media. An object of the present invention is to provide an optical recording / reproducing device that can be used.

[0010]

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. In an optical recording / reproducing apparatus equipped with the above, a track pitch detecting means for detecting a track pitch of an optical recording medium, and 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 according to the track pitch. Is equipped with.

The track pitch detecting means includes drive signal generating means for outputting a drive signal to the lens driving section so that the condenser lens moves or vibrates in the radial direction of the optical recording medium, and the condenser lens moves or vibrates. It is also possible to have a counting means for counting the track crossing signals detected with the above.

[0012]

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. Here, the track pitch of the optical recording medium is previously detected by the track pitch detection means, and the servo condition is switched by the servo condition switching means according to the track pitch, so that the condenser lens can be driven under the optimum servo condition. Stable recording, reproduction, or erasing can be performed.

In order to detect the track pitch, a drive signal may be output from the drive signal generating means to the lens drive section, and the condenser lens may be moved or vibrated in the radial direction of the optical recording medium. At this time, with the movement of the condenser lens, a track crossing signal is generated every time the laser spot irradiated on the optical recording medium crosses the track. The track pitch can be detected by counting the track crossing signals and obtaining the number of tracks that the laser spot crosses when the condenser lens is moved by a predetermined distance in advance. That is, the narrower the track pitch, the larger the number of tracks traversed by the laser spot. Therefore, the servo condition may be switched based on this number of tracks.

[0014]

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 has a spindle motor 11 for rotating the optical recording medium 10 and a laser beam for the optical recording medium 10, as shown in the main part of the block diagram of FIG. An optical head 12 that irradiates and receives the reflected light from the optical recording medium 10, a laser drive unit 14 that drives a laser that is a light source of the optical head 12, and a servo signal and an information signal from the reflected light received by the optical head 12. The signal reproduction unit 18 including the servo signal reproduction unit 16 and the information signal reproduction unit 17 for reproducing the light, the actuator 21 for moving the condenser lens 20 for condensing the laser light on the optical recording medium 10, and driving the condensed light. The lens drive unit 22 is so controlled that the spot always follows a predetermined track. Furthermore, a control unit 24 that outputs recording data and controls other parts, a modulation unit 26 that modulates the recording data output from the control unit 24, and an information signal reproduced from the information signal reproducing unit 17. Demodulating section 28 for demodulating the data into a data, and the lens driving section 22 according to the signal from the control section.
The servo condition switching unit 30 for switching the servo conditions of No. 1 and the track pitch detection unit 32 for detecting the track pitch of the optical recording medium 10 are provided.

The track pitch detector 32 outputs a drive signal to the lens driver 22 so that the condenser lens 20 moves in the radial direction of the optical recording medium 10, as shown in the block diagram of FIG. The signal generation unit 34 and the movement of the condenser lens 20, that is, the track crossing signal generated every time the laser spot irradiated on the optical recording medium 10 by the condenser lens 20 crosses a track is detected, and its waveform is detected. A waveform shaping section 36 for shaping into a pulse waveform, and a counter 3 for counting the number of pulses output from the waveform shaping section 36.
8 and. The counter 38 is reset by the count start signal from the controller 24, and the drive signal generator 34 starts outputting the drive signal.

The servo condition switching unit 30 is provided with, for example, D / A conversion units 42 and 43 and amplifiers 44 and 45 for converting a digital signal output from the control unit 24 into an analog signal as shown in FIG. Further, the lens driving unit 22 is
A tracking servo AGC unit 46 that adjusts the servo gain so that the tracking error signal is constant with respect to variations in the amount of reflected light and the like, and a jump signal generation unit 48 that generates a jump pulse and a brake pulse are provided.
Here, the tracking servo AGC unit 46 is composed of an analog divider, a multiplier or the like whose gain changes proportionally according to the control voltage. For example, the tracking servo AGC unit 46 uses the output of the amplifier 44 as a control voltage. By inputting, the magnitude of the tracking servo gain can be controlled by a digital signal from the control unit 24. In addition, the jump signal generator 48 includes an amplifier 45.
Generates a jump pulse and a brake pulse having a magnitude corresponding to the output voltage of the.

Next, the procedure of recording, reproducing, or erasing by the optical recording / reproducing apparatus of the present invention will be described with reference to the flowchart of FIG.

Generally, as the track pitch of the optical recording medium 10 becomes narrower, the push-pull signal strength used for tracking decreases. Therefore, in order to perform stable tracking, increase the tracking servo gain,
It is necessary to 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, the servo conditions such as the tracking servo gain and the track jump condition need to be set to optimum values according to the track pitch of the optical recording medium 10.

Therefore, when the control is started, first, the spindle motor 11 is stopped so that the optical recording medium 10 is stopped. Next, the condenser lens 20 is moved to the recording area of the optical recording medium 10, that is, the area where the track is provided.
The optical head 12 is moved so that the light emitted from the optical head 12 is irradiated, and the laser drive unit 14 continuously emits the laser light source of the optical head 12. At this time, the lens driving unit 22 controls the focusing lens 20 based on the focus error signal output from the servo signal reproducing unit 16 to turn on the focus servo. As a result, the laser light is always focused by the condenser lens 20 on the recording surface of the optical recording medium 10.

In this state, the control section 24 outputs a track number counting start signal to the track pitch detection section 32. The track pitch detection unit 3 receives the counting start signal.
At the same time when the second counter 38 is reset, the drive signal generator 34 outputs a sweep signal as shown in FIG. 5A to the lens driver 22, and the condenser lens 20 moves in the radial direction of the optical recording medium 10 by a predetermined distance. To do. The amplitude of the sweep signal and the moving distance of the condenser lens 20 are substantially proportional to each other. When the sign of the sweep signal is reversed, the moving direction of the condenser lens 20 is also reversed. Along with the movement of the condenser lens 20, the laser spot focused on the recording surface also moves while traversing the track. Therefore, a track crossing signal as shown in FIG. 32 waveform shaping section 36
Is output to. When the track pitch is wide, the track crossing signal has a large signal amplitude and the number of crossings is small as shown in FIG.

On the other hand, when the track pitch is narrow, the signal amplitude becomes small and the number of traverses becomes large as shown in FIG. Therefore, in the waveform shaping section 36, by appropriately binarizing at the reference level, for example, the level at which the signal amplitude becomes zero, a number of rectangular wave pulses corresponding to the number of traversed tracks as shown in FIG. Be done. Therefore, the track pitch can be detected by counting the number of pulses output from the waveform shaping section 36 with the counter 38. That is, when the drive signal amplitude is selected such that the distance that the laser spot moves on the recording surface of the optical recording medium 10 is 80 μm, the number of tracks counted by the counter 38 is the same as that of the optical recording medium 10. When the track pitch is 1.6 μm, it is 50, and the track pitch is 1.
In the case of 0 μm, it is 80. As described above, the track pitch detection unit 32 does not need to detect the track pitch itself, but may detect a signal for obtaining information about the track pitch as in the present embodiment.

The number of tracks counted by the counter 38 is output to the controller 24, and the controller 24 selects the servo condition from the number of tracks. The control unit 24 stores servo conditions for some track numbers in advance. Further, normally, the optical recording medium 10 is formed with a mirror portion for detecting a track offset, and since no track crossing signal is generated in this mirror portion, the number of tracks actually counted by the counter 38 is crossed. There is an error with the number of tracks. Therefore, the servo condition for the track number closest to the counted track number is selected.

Servo condition data such as the selected tracking servo gain and track jump condition are stored in the control unit 24.
Is output to the servo condition switching unit 30. The servo condition data is converted to an analog signal by the D / A converters 42 and 43, and then output from the amplifier 44 and applied as a control voltage to the tracking servo AGC unit 46, and the tracking servo gain and the jump signal generator are also applied. The output from amplifier 45 applied to 48 sets the magnitude of the jump and brake pulses. That is, the track pitch is narrow, that is, the track pitch detection unit 32.
When the number of tracks counted in is large, the track pitch is wide, that is, the tracking servo gain is set to be larger than in the case where the number of tracks counted is small,
The magnitudes of the jump pulse and the brake pulse are set small.

After setting the servo conditions, the control unit 24 turns on the spindle motor 11 to rotate the optical recording medium 10 and turns on the tracking servo, and the lens driving unit 22 drives the condenser lens 20 to perform tracking, etc. Servo is performed optimally. As a result, recording, reproduction, or erasing can be stably performed on the optical recording medium 10.

As described above, the track pitch detecting section 32 allows the optical recording media 10 having different track pitches to be
Information regarding the track pitch is detected, and based on this, the servo condition switching unit 30 switches the servo conditions such as the tracking servo gain and the track jump condition to the optimum values, so that the optical recording media 10 with various track pitches can be obtained. , Stable recording, reproduction or erasing can be performed.

Although one embodiment of the present invention has been described in detail above with reference to FIGS. 1 to 5, the present invention can be implemented in other modes.

For example, the laser output may be changed when the optical recording medium 10 is stopped and when it is rotated. That is,
When the optical recording medium 10 is stopped, the laser is locally emitted continuously, so that the temperature of the irradiation point rises and the optical recording medium 10 is increased.
May be damaged. Therefore, the optical recording medium 10
The laser output may be reduced at the time of stopping. This can prevent the optical recording medium 10 from being damaged. Further, when the laser output is small, the servo tends to be unstable, and the servo may not be properly applied especially when the focus servo is pulled in. In order to prevent this, after the optical recording medium 10 is rotated, the laser drive unit 14 causes the laser to emit light with a normal output, and the focus servo is turned on. Then, with the focus servo turned on, the laser output may be reduced by the laser drive unit 14, the optical recording medium 10 may be stopped, and the track pitch may be detected. As described above, the operation of the optical recording / reproducing apparatus of the present invention is not limited to the flowchart shown in FIG. 4, and various modifications can be made.

In the flowchart shown in FIG. 4, the track pitch is detected after the optical recording medium 10 is stopped, but the track pitch may be detected while the optical recording medium 10 is being rotated. Here, in order to reduce the influence of the eccentricity of the optical recording medium 10, the track crossing signal may be measured every half circumference. That is, if, unless the optical recording medium 10 is eccentric, as shown in FIG. 6 (a), the laser spot 50 by sweeping the condenser lens 20 is moved from the track 52 to the track 53, traversed in a range of S ₀ The number of tracks is counted. However, in reality, due to the eccentricity of the optical recording medium 10, the entire track moves to the right by S ₂ with respect to the laser spot 50, as shown in FIG. As a result, the laser spot 50 does not reach the track 53,
Move to truck 55. Therefore, the number of crossing tracks is counted in the range of S ₁ , and the portion of the range of S ₂ corresponding to the amount of eccentricity is not counted. On the other hand, when the optical recording medium 10 is rotated by a half circumference from the state of FIG. 6B, the entire track is moved leftward by S ₂ as shown in FIG. 6C. Therefore, the laser spot 50 moves over the track 53 to the track 56. Therefore, the number of crossing tracks is counted in the range of S ₃ that joined portions of the range of S ₂ corresponding to the eccentricity in the range of S _0. Summarizing the above, S ₁ = S ₀ −S ₂ (1) S ₃ = S ₀ + S ₂ (2) Therefore, if the sum of the number of crossing tracks at these two points is calculated, S ₁ + S ₃ = 2S ₀ (3 The number of tracks is in the range. That is, by counting the number of crossing tracks at positions different from each other by a half circumference and obtaining the sum, it is possible to count the number of crossing tracks only in the range of S ₀ without being affected by the eccentricity.

As for the sum of the number of crossing tracks, the count value of the number of crossing tracks at a certain point is temporarily stored in the control unit 24, and the count value of the number of crossing tracks after the optical recording medium 10 is rotated by half a turn is calculated as It can be obtained by adding the stored value.

In the track pitch detector 32, a counter 38 is operated by a signal from the controller at the start of sweeping.
Is reset, counting is started, and counting is interrupted at the end of the sweep. Next, after the optical recording medium 10 has rotated a half turn, the sweep is restarted, but the counter 38 is not reset, and the counting is restarted, so that at the end of the sweep, traverse tracks at positions different from each other by a half turn. The sum of the numbers may be counted by the counter.

Although the sum of the numbers of crossing tracks is twice the number of crossing tracks in the above-described embodiment, the servo condition may be selected from the number of tracks which is half this value. The servo condition may be selected from the sum of the numbers themselves.

In the case of the optical recording medium 10 having a small eccentricity, the sweep time is sufficiently shortened to count the number of traverse tracks, so that it is not necessary to count at the time of a half-turn. Furthermore, the number of tracks can be accurately counted by slowing the rotation of the optical recording medium 10 or shortening the moving distance of the condenser lens 20.

The waveform of the sweep signal is not particularly limited. For example, the repetitive waveform as shown in FIG. 7A may be used, and the counting error is reduced by repeatedly counting and obtaining the sum or average thereof. Further, the sweep direction may be reciprocating as shown in FIG. Further, it may change sinusoidally as shown in FIG. Further, the sweep may be performed on only one side as shown in FIG.

Further, when the sweeping of the condenser lens 20 is started, when the sweeping is finished, or near the change of the sweeping direction, the operation is unstable and the counting error of the number of tracks increases. The end time, the start time of counting, and the end time of counting may be controlled separately. For example, as shown in FIG. 8, the counting does not start at the start of the sweep, and the counter is reset at the time of t ₁ when the sweep signal amplitude reaches the first predetermined value, for example, A ₁ , and the counting is started and the sweep is started. The signal amplitude is the second predetermined value A
_The counting may be terminated at t ₂ when it reaches ₂ . As a result, counting is not performed at an unstable point due to delay in movement of the condenser lens 20 at the start of sweeping, unnecessary vibration, or the like, and thus a counting error is reduced. Further, the distance that the laser spot moves is always constant between the sweep signal amplitudes A ₁ and A ₂ , so that the counting accuracy is improved.

Further, the amplitude of the sweep signal or the moving distance of the condenser lens 20 is not particularly limited. The larger the moving distance of the condenser lens 20, the larger the number of traversing tracks, so that the track pitch can be easily distinguished.

Further, the structure of the track pitch detecting section 32 is not limited to that shown in FIG. 2, and various structures can be used. For example, a plurality of counters may be provided and the servo conditions may be switched by the signal of each counter. That is, as shown in FIG. 9, when the amplitude of the drive signal is selected such that the distance the laser spot moves is 80 μm, the number of pulses output from the waveform shaping circuit 36 is counted and measured. The number is 45,
There may be provided counters 60, 61, 62, 63 which generate signals when the number becomes 53, 62, 74 or more. When the moving distance of the laser spot is 80 μm, the numbers of pulses generated corresponding to the track pitches of 1.6, 1.4, 1.2 and 1.0 μm are 50, 57, 67 and 80, respectively. When it is 0.6 μm, a signal is generated from the counter 60. Counter 6 when the track pitch is 1.4 μm
Although the signal is generated from 1, the signal of the counter 60 is reset at this time. In this way, the track pitch 1.
Signals are output from the counters 60, 61, 62 and 63 respectively corresponding to 6, 1.4, 1.2 and 1.0 μm. These signals control the switches 64, 65, 66, 67 of the servo condition switching unit 30, for example. In the servo condition switching unit 30, tracking servo gains G ₁ , G ₂ , G ₃ , G ₄ are set according to each track pitch, and the switches 64 selected by the outputs of the counters 60, 61, 62, 63, Amplifier 44 through 65, 66 and 67
To the servo condition. Here, the number of the counters 60, 61, 62, 63 and the count value for generating the signal are appropriately changed depending on the track pitch and the sweep distance. Further, the output of each counter may be once input to the control unit 24, and the servo condition may be switched through the control unit 24. Although only the tracking servo gain is described with reference to FIG. 9, other conditions such as a track jump condition can be similarly switched.

The method of detecting the track pitch is not limited to counting the number of traversing tracks. For example, as shown in FIG. 10, it may be detected by a pulse number converter 70 that generates a voltage according to the number of pulses output from the waveform shaping section 36. That is, as the track pitch becomes narrower and the number of traversing tracks increases, the output voltage of the pulse number converter 70 also increases, so that the servo condition can be switched based on this output voltage. This output voltage may be output once to the control unit 24, and the servo condition may be selected in the control unit 24. Also, input the output voltage to the servo condition switching unit 30,
It may be amplified to a predetermined magnitude and used as a control voltage for the tracking servo AGC unit 46 and the like.

Further, the track pitch may be detected from the change of the drive signal when the track crosses a predetermined number. For example, as shown in FIG. 11, a signal monitor 72 that detects the magnitude of the sweep signal of the drive signal generator 34 is provided, and the change of the sweep signal when the count value of the counter 38 reaches a predetermined value is detected. The narrower the track pitch, the smaller the movement distance of the laser spot required to cross the track by a predetermined number, and therefore the smaller the change in the sweep signal detected by the signal monitor 72. Therefore, the servo condition may be switched based on the output of the signal monitor 72.

Further, as shown in FIG. 12, a means for detecting the track pitch may be provided in addition to the optical head 12.
For example, a laser 75 is provided to irradiate the optical recording medium 10 with laser light. At this time, diffraction occurs due to the track of the optical recording medium 10, and the diffraction angle of this diffracted light increases as the track pitch becomes narrower. Therefore, the diffraction angle is detected by the diffraction angle detector 76 such as a photodiode array and the track pitch detection unit 77. By detecting, the track pitch can be detected.

Further, the configuration of the servo condition switching section 30 is not limited to the embodiment shown in FIG. 3 or FIG. For example, as shown in FIG. 13, 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, and the control is performed. The switching unit 8 is operated by the signal from the unit 24.
It may be switched to a required value at 0 and 81. That is, the track pitch of the high-density optical recording medium 10 is 1.4, 1.
Since it is set to a specific value such as 2, 1.0, 0.9 μm, the configuration of the servo condition switching unit 30 becomes simple by preparing only the servo conditions corresponding to these. In addition, the resistance value or the like that determines the tracking servo gain may be directly switched without using the amplifiers 44 and 45, 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, the pulse width is wide when the track pitch is wide as shown in FIG. 14A, and the pulse width is wide when the track pitch is narrow as shown in FIG. You may switch so that width may become narrow. Further, the size and width of the pulse are constant, and as shown in FIG. 15A, the number of pulses is increased when the track pitch is wide, and when the track pitch is narrow, as shown in FIG. 15B. Alternatively, the number of pulses may be changed so as to be reduced.
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 30 is simplified. In addition, the absolute value of the magnitude of the jump pulse and the brake pulse, the pulse width,
The number of pulses need not be the same as each other.

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. 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 optical recording / reproducing apparatus of the present invention does not have to perform all 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 / reproducing apparatus of the present invention is also not particularly limited. For example, an optical recording medium compatible with magneto-optical recording, phase change recording, write-once recording may be used. Alternatively, a read-only optical recording medium such as a CD-ROM may be used. Further, the structure of the optical recording medium is not particularly limited, and in addition to the structure having a normal guide groove, for example,
As shown in FIG. 16 which is a cross-sectional view in the radial direction, a guide layer 92, in which a metal such as Ta having a predetermined width is provided along a spiral or concentric circles on a substrate 90 such as glass, is formed on the guide layer 92. A structure including the interference layer 94, the recording layer 96, and the protective layer 98 provided may be used. As a result, both sides of the laser spot 99 with which the recording layer 96 is irradiated are shielded by the guide layers 92, crosstalk is reduced, and an optical recording medium having a narrow track pitch can be easily manufactured.

The optical recording medium used in the optical recording method 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.

[0047]

As is clear from the above description,
The optical recording / reproducing apparatus of the present invention is provided with the track pitch detecting means and the servo condition switching means for switching the servo conditions such as the tracking servo gain and the track jump condition of the lens driving section based on the signal detected by the track pitch detecting means. As a result, servos such as tracking can be stably performed on optical recording media having different track pitches, 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 a main part of a track pitch detection unit.

FIG. 3 is a block diagram showing main parts of a servo condition switching unit and a lens driving unit.

FIG. 4 is a flowchart showing an operation procedure of the optical recording / reproducing apparatus of the present invention.

FIG. 5 is an explanatory diagram showing a track pitch detection method in a track pitch detection unit, in which (a) is a sweep signal waveform,
(B) And (c) is an explanatory view showing a track crossing signal and (d) an output signal from a waveform shaping section.

6A to 6C are explanatory views showing another embodiment of the track pitch detecting method in the track pitch detecting unit.

7A to 7D are explanatory diagrams showing another example of the sweep waveform in the track pitch detection unit.

FIG. 8 is an explanatory diagram showing another embodiment of the track pitch detecting method in the track pitch detecting unit.

FIG. 9 is a block diagram showing main parts of a track pitch detection unit and a servo condition switching unit in another embodiment of the optical recording / reproducing apparatus of the present invention.

FIG. 10 is a block diagram showing a main part of a track pitch detecting section in another embodiment of the optical recording / reproducing apparatus of the present invention.

FIG. 11 is a block diagram showing a main part of a track pitch detecting section in another embodiment of the optical recording / reproducing apparatus of the present invention.

FIG. 12 is a block diagram showing a main part of another embodiment of the optical recording / reproducing apparatus of the present invention.

FIG. 13 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.

14 (a) and 14 (b) are explanatory views showing jump pulse and brake pulse waveforms in another embodiment of the optical recording / reproducing apparatus of the present invention.

15 (a) and 15 (b) are explanatory diagrams showing jump pulse and brake pulse waveforms in another embodiment of the optical recording / reproducing apparatus of the present invention.

FIG. 16 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. 17 is a block diagram showing a schematic configuration of a conventional optical recording / reproducing apparatus.

FIG. 18 is an explanatory diagram showing waveforms of a jump pulse and a brake pulse in the conventional optical recording / reproducing apparatus.

[Explanation of symbols]

10 Optical Recording Medium 12 Optical Head 18 Signal Reproducing Section 20 Condensing Lens 22 Lens Driving Section 30 Servo Condition Switching Section (Servo Condition Switching Means) 32 Track Pitch Detection Section (Track Pitch Detection 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 comprising: a signal reproducing section that outputs a servo signal and an information signal based on the optical recording medium; and a lens driving section that drives the condenser lens of the optical head based on the servo signal. An optical recording / reproducing apparatus comprising: a track pitch detecting means for detecting a track pitch; and a servo condition switching means for switching a servo condition of the lens driving section according to the track pitch. 2. The optical recording / reproducing apparatus according to claim 1, wherein the track pitch detecting means applies a drive signal to the lens driving section so that the condenser lens moves or vibrates in the radial direction of the optical recording medium. An optical recording / reproducing apparatus comprising: a drive signal generating means for outputting and a counting means for counting a track crossing signal detected due to movement or vibration of the condenser lens. 3. The optical recording / reproducing apparatus according to claim 1, wherein the servo conditions are a tracking servo gain and a track jump condition.