JP2000331342A - Optical recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable stable and highly accurate tracking control even in an optical recording device having no guide groove. SOLUTION: Tracking control is performed by a control section 12 so that after a track for detecting bit width is formed, the track is irradiated with an optical spot 9 in the next scanning. An output from an optical detector 3 at the time is compared with the prescribed value previously stored in a memory 11 by output comparing sections 14a, 14b, and a formed bit width is controlled by a control section 12 so that the bit width is made to the prescribed value. After the prescribed operation of the bit width, recording and reproducing of information are performed by a profiling tracking system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording apparatus for recording and reproducing information using light.

[0002]

2. Description of the Related Art In recent years, optical recording media such as optical cards and optical tapes for recording / reproducing information such as sound and images using light emitted from a laser or the like, and optical recording apparatuses have been actively developed. Among them, as a conventional optical recording apparatus for recording / reproducing by rotating a part of an optical path until a laser beam is converged, for example, an apparatus as shown in FIG. 11 shown in JP-A-8-287481. There is. Laser diode 101
(Hereinafter referred to as LD) is emitted from the beam splitter 1
02 and enters the rotating optical unit 103. The rotating optical unit 103 is a rotating drum 1 rotated by a rotating motor 104.
The rotary drum 105 has reflecting mirrors 106 and 107 for deflection and an objective lens 108. The light incident on the rotation optical unit 103 is reflected by the reflection mirror 10.
The light is converged by the objective lens 108 through the optical lenses 6 and 107 to form a minute light spot, which is irradiated onto the optical recording medium 109. The light reflected by the optical recording medium 109 passes through the same path in the opposite direction to the beam splitter 102, is deflected by the beam splitter 102, and is deflected by the photodetectors 110 and 111.
Incident on. Based on the light detected by the light detectors 110 and 111, a reproduced signal of information recorded on the optical recording medium 109 is obtained, and at the same time, the amount of displacement of the light by the light detectors 110 and 111 is detected. The position of the light spot (focus control and tracking control) is adjusted by driving the actuator 112 placed in the optical path. The optical recording medium 109 is on the tray 113 and is conveyed in the direction of arrow F by the conveying motor 114 to scan information on the optical recording medium 109 one after another.

FIG. 12 is a diagram showing tracks formed on a card-shaped optical recording medium 109 using the above-mentioned conventional optical recording apparatus. Since the rotating optical unit 103 in FIG. 11 scans while rotating, the trajectory of the light spot draws a circle. Therefore, FIG.
As shown in FIG. 2, an arc-shaped track 115 having a rotation radius of the rotation optical unit 103 is formed.

[0004] At this time, a push-pull method is used for tracking control as position adjustment of the light spot, for example.
In this method, guide grooves such as grooves are provided in advance for tracking control. The groove acts as a diffraction grating,
The reflected and diffracted light of the irradiated laser light is received by a two-segment photodetector symmetrically arranged with respect to the track center, and the output difference is calculated to obtain a tracking error signal. The tracking actuator is operated based on the tracking error signal to cause the light spot to accurately follow the recording track.

There are other known methods for obtaining such a tracking error signal, such as a three-spot method. However, any of these methods requires a guide groove or the like to be formed in a recording medium in advance.

As a recording medium having no guide groove, for example, a tracking method disclosed in Japanese Patent Application Laid-Open No. 60-15831 is known. In this method, the first track is recorded with only the mechanical accuracy, and the subsequent track is recorded at a fixed interval while performing tracking by using the immediately preceding track recorded.

[0007]

As described above, FIG.
The optical recording apparatus as shown in FIG. 1 has an advantage that the recording position accuracy can be ensured, but a guide groove or the like must be formed in the optical recording medium in advance, which requires a manufacturing process and an optical recording. When a groove is formed in a medium, there is a problem that thickness unevenness or the like is likely to occur when a ferromagnetic thin film is deposited, and characteristics cannot be kept constant.

In view of the above, a recording method based on the above-described tracking is conceivable. In general, at the time of recording information, variations in sensitivity of an optical recording medium, changes in the intensity of an illuminated light source, ambient temperature, etc. As a result, the width of the formed pit changes. In the conventional tracking method described above, only the position accuracy of the track is considered, and the accuracy of the pit width is not considered. However, if the pit width changes, the linear zone changes when tracking control is performed, and as a result, the track position also shifts, and accurate tracking cannot be performed. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical recording apparatus capable of performing stable and highly accurate tracking control even in an optical recording medium having no guide groove or the like. With the goal.

[0010]

SUMMARY OF THE INVENTION The present invention provides a light source for emitting light for recording and reproducing information on an optical recording medium, and a light spot on the optical recording medium by converging light from the light source. A light converging means to be constituted, a rotating means for rotating the light converging means, a control means for controlling the intensity of the light emitted from the light source, and a light detecting means for detecting the reflected light of the light spot from the optical recording medium, A memory means storing a specified value of the pit width to be formed, and a comparing means for comparing a detection result from the light detecting means with a specified value of the memory means,
After the track for detecting the pit width is formed on the optical recording medium by the light spot, the track is irradiated with the light spot in the next scanning, and the detection result from the light detecting means and the specified value of the memory means are used. Are compared by a comparison means, and the control means controls the pit width to be a specified value by a control means.

Further, the light detecting means is constituted by a plurality of division portions for dividing the light spot into at least two or more divided regions and individually detecting each divided region.

The apparatus further includes tracking servo means for outputting a substantially sinusoidal drive current, and tracking actuator means for receiving the drive current and vibrating the rotating means up and down in accordance with the drive current. After the track for detecting the light spot is formed on the optical recording medium by the light spot, in the next scan, the light spot is irradiated onto the track while wobbling.

Further, the specified value of the pit width is stored in the memory means as a time parameter corresponding to the scanning speed.

Further, the apparatus further comprises a light beam splitting means provided on the rotating means for splitting the light from the light source into a plurality of beams. After performing an operation of controlling the formed pit width to a specified value, Recording and reproduction of information are performed by a tracking method using a plurality of beams.

Further, the prescribed value of the pit width is such that the ratio k (= pit width / light spot diameter) of the pit width to the light spot diameter is:
0.3 ≦ k ≦ 0.7.

Further, a track for defining the pit width and a track for recording data relating to the light intensity when the track is formed are formed on the optical recording medium.

Also, a plurality of tracks for defining the pit width are formed in advance by the light beams having different intensities.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an optical recording apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an example of the optical recording device according to the first embodiment. In FIG. 1, reference numeral 1 denotes an optical pickup, which comprises the following main components. Reference numeral 2 denotes a laser diode (hereinafter, referred to as an LD). Reference numeral 3 denotes a two-segment photodetector (main spot photodetector), each of which includes a split portion Sa (reference numeral 3a) and Sb (reference numeral 3b). Reflected light is projected. Reference numeral 4 also denotes a two-segment photodetector (sub-spot photodetector), which is composed of split parts Da (reference numeral 4a) and Db (reference numeral 4b), and reflects light reflected by the sub-spot. Reference numeral 5 denotes a tracking actuator, 6 denotes an objective lens for condensing light from the LD 2, and 7 denotes a rotary rotor on which the objective lens 6 and a diffraction grating (not shown) are mounted.

In FIG. 1, reference numeral 8 denotes a card-like recording medium using, for example, a cyanine dye. Reference numeral 9 denotes a main spot (0) divided into three beams by the diffraction grating.
Secondary light), 10a and 10b are secondary spots (± 1
The distance between the main spot 9 and the sub-spot 10a on the recording medium 8 is L, which is a predetermined light intensity division ratio (main spot> sub-spot). 11 is a memory, 1
2 is a control unit such as a CPU, 13 is an output control unit that controls the output of the LD 2 based on the control of the control unit 12, 14a and 14
b is an output comparison unit for comparing the outputs from the photodetectors 3a and 3b with a predetermined reference value described later, and 15 is a tracking error that generates a tracking error signal (TE) based on the outputs from the photodetectors 4a and 4b. Signal operation unit,
Reference numeral 16 denotes a tracking servo unit that drives the tracking actuator 5 based on the tracking error signal (TE) from the tracking error signal calculation unit 15. Reference numeral 17 is mounted near the rotating rotor 7 to detect the rotational position of the rotating rotor 7 and to rotate. A rotation position sensor for transferring position information to the control unit 12, a rotation motor 18 for rotating the rotation rotor 7 under the control of the control unit 12, and a conveyance motor 19 for conveying the recording medium 8.

FIG. 2 is a diagram showing the operation of the optical storage device shown in FIG. FIG. 2A is a view showing a recording operation, in which reference numeral 20 denotes a rotation trajectory of the rotating rotor 7 in the direction of the arrow R;
(W) shows the main spots 9 and 21 having the intensity at the time of recording, and the tracks formed by the light spots 9 (W). FIG.
9B is a diagram showing a pit width reading operation, and FIG.
Is a main spot 9 having the intensity at the time of reading the pit width. Also,
In these figures, S indicates the start position of the track 21.

Next, the operation will be described with reference to FIGS. First, an operation for defining the pit width is performed. Recording medium 8
Is inserted from an insertion opening (not shown), the control unit 12 starts the transport motor 19 and transports the recording medium 8 to a predetermined position. When the control unit 12 reaches the home position, the control unit 12
To rotate the rotating rotor 7 in the direction of arrow R in FIG. At this time, the rotation position information of the rotation rotor 7 is transferred from the rotation position sensor 17 to the control unit 12 as needed. Next, the control unit 12 detects that the rotation rotor 7 has reached the predetermined start position (S) of the recording medium 8 by the rotation position sensor 17, sends a control signal to the output control unit 13, and outputs a predetermined recording intensity. LD2 is oscillated so as to output the LD light. Then, the main spot 9 (W) at this time causes the track 21 to move.
Is formed.

Next, the control unit 12 controls the output control unit 13 so that the output of the LD 2 becomes an output at the time of reading (a level that cannot be written on a recording medium). When the rotating rotor 7 makes a round and reaches the track 21 again, the main spot 9 (R)
Irradiates the track 21 and forms a reflected and projected image on the photodetector 3 by the objective lens 6. Since the photodetector 3 is divided into two parts, the upper half of the projected image is divided into the divided parts Sa (reference numeral 3).
In (a), the lower half is projected on the dividing part Sb (reference numeral 3b),
An output corresponding to the projection intensity (hereinafter, detection output) is output (this principle will be described later). This detection output is input to the output comparison units 14a and 14b, respectively. The output comparing unit 14a compares an output value detected by the dividing unit Sa of the photodetector 3 with a reference value of the optimum pit width from the memory 11 through the control unit 12. The reference value of the optimum pit width stored in the memory 11 is determined in advance by the sensitivity of the medium and the LD used.
Determine from strength. The output comparison unit 14a outputs a match signal to the control unit 12 when the comparison results match, and outputs a comparison error signal when the comparison results differ. The operation of the output comparison unit 14b is the same.

When the comparison results of the output comparison sections 14a and 14b do not match, the following operation is performed. When detecting the comparison error signal, the control unit 12 activates the transport motor 19 to move the recording medium 8 to a position where the recording medium 8 does not overlap the track 21. It is desirable that this movement amount be a distance that does not affect the crosstalk of the track 21. The control unit 12 outputs a command signal to the output control unit 13 so that the LD 2 oscillates LD light having a different recording intensity. Again, set LD
Light forms a new track. Next, the output of the photodetector 3 as described above is compared with the output comparison units 14a and 14b.
The comparison operation is performed in the above (the description is omitted because it is the same as above). This operation is repeated until the comparison results of the output comparison units 14a and 14b match.

When the comparison results match and the operation of setting the pit width to the reference value of the optimum pit width is completed, next, the recording / reproducing operation of information data such as images and sounds is performed. This operation is basically based on the tracking method, but will be described in detail with reference to FIG. FIG. 3A shows a case where information is recorded,
Reference numeral 21A denotes a track having an LD light amount different from that of the track 21, and a track which coincides with an optimum pit width of a predetermined reference value. Reference numerals 22 and 22A denote information tracks which are being formed by the main spot 9 for recording. is there. FIG.
(B) is an operation diagram when the information recorded in (a) is reproduced.

First, the operation during recording (FIG. 3A) will be described. When the control unit 12 detects the coincidence signal by the comparison operation after the formation of the track 21A, the conveyance motor 19
Is started to move the recording medium 8 by a predetermined pitch amount L (the upper diagram in FIG. 3A). This movement amount is the distance L between the main spot 9 and the sub spot 10a on the recording medium 8. Here, the main spot 9 is a recording spot, and the sub spot 10a is a tracking spot. Rotating rotor 7
Is rotated in the direction of arrow R and reaches a predetermined position. When the sub-spot 10a starts to scan on the track 21A, its reflected projected image is projected on the photodetector 4, and a signal corresponding to the projection intensity is output from the division units 4a and 4b. This output is calculated by the tracking error signal calculation unit 15 by subtracting the output db of the division unit 4b from the output da of the division unit 4a, that is, (da
−db) to calculate the tracking error signal TE
Get. This signal TE is input to the tracking servo unit 16, and the tracking servo unit 16 drives the tracking actuator 5 so that the signal TE becomes substantially 0 to perform a tracking operation. At this time, the control unit 12 outputs a signal corresponding to the information to the output control unit 13, and oscillates the LD 2 with the LD light intensity that can obtain the previously obtained optimum pit width. Thus, the main spot 9 records the track 22 on the recording medium 8 as a pit row. When the recording on the track 22 is completed, the recording medium 8 is conveyed by the distance L by the conveying motor 19, so that the information track 22 is irradiated with the sub spot 10a this time (lower view in FIG. 3A). . The tracking error signal TE is generated by the sub spot 10a using the track 22 to form the track 22A.
Hereinafter, this operation is repeated until information recording is completed.

Next, the operation during information reproduction (FIG. 3B) will be described. First, the track 21A is sought, and the medium is transported so that the track 21A is irradiated by the sub spot 10a (the upper diagram in FIG. 3B). Similarly to the recording operation, the track 21A is projected on the photodetector 4 and used for tracking. At this time, the pits of the track 22 are detected by the photodetector 3 for detecting the projected image by the main spot 9, and a reproduced output is obtained. When the scanning of the track 22 is completed, the recording medium 8 is moved by the distance L by the transport motor 19, and the track 22 is tracked while tracking the track 22.
The information of A is reproduced (the lower diagram in FIG. 3B). This operation is repeated until the reproduction of the information is completed.

Here, the principle of detecting the pit width will be described. The pit width formed on the optical recording medium is determined by the sensitivity of the optical recording medium, the strength of the LD, and the like.
If the sensitivity of the optical recording medium is high, the pit width increases with LD light having the same intensity, and if the sensitivity of the medium is low, the pit width decreases. Further, even if the sensitivity of the optical recording medium is the same, if the LD intensity is large, the pit width becomes large,
If the strength is small, the pit width will be small. Therefore, the width of the pits to be formed differs due to variations in sensitivity at the time of manufacturing the optical recording medium, variations in LD oscillation due to a change in ambient temperature during operation, and the like.

FIG. 4 is a schematic diagram showing the relationship between the focused light spot and the light detector. FIG. 4A shows a light spot 9 on a recording medium 8 and pits of a track formed by the light spot 9. 24, 25 and 26 are pits with different LD light intensities. Since scanning is performed in the direction of the arrow R, these pits 24 to 26 are elongated in the direction of the R. Also,
W indicates the pit width, and D indicates the light spot diameter. FIG.
(B) shows pits projected on the photodetectors 3a and 3b. FIG. 4A shows the pit width W (the width in the direction perpendicular to the arrow R, here, the width of the pit 24) and the light spot 9.
4B shows a case where the relationship with the light spot diameter D is standard (specified value). FIG. 4B shows a case where the pit width (the width of the pit 25) is smaller than the light spot diameter. ) Shows a case where the pit width (width of the pit 26) is larger than the light spot diameter.

Since the pits 24, 25 and 26 are concave due to the LD light, the pits 24, 25 and 26 have a lower reflectance than the surroundings. Therefore, in the case of FIG. 4A, the reflection portions projected on the photodetectors 3a and 3b are 24a and 24b indicated by oblique lines,
This reflection portion becomes the hatched portions 24a and 24b on the photodetectors 3a and 3b. The same applies to the cases of FIGS. 4 (2) and 4 (3), and the reflecting portions projected on the photodetectors 3a and 3b are hatched portions 25a and 25b and hatched portions 26a and 26b, respectively. The detection output of the light detector 3 is proportional to the area of the hatched portions 24a and 24b and the light intensity thereof. For this reason, the detection output of each of the divisions 3a and 3b of the photodetector 3 is (2)>(1)> in order from the smaller pit width according to the pit width for the light spot.
(3). Therefore, by using this detection output, the pit width can be set to a value that defines the pit width with respect to the light spot diameter in the above-described apparatus and operation. In addition,
In this figure, for the sake of simplicity, it is assumed that the reflecting portions 24a and 24b directly project on the light detectors 3a and 3b. However, in actuality, the size of the reflecting portion and the size on the light detector 3 depend on the magnification of the optical system. It is different.

As described above, in this embodiment, as shown in FIG. 2, the formed track is scanned again so that the optimum pit width can be formed from the output from the photodetector 3 at that time. Therefore, the pit width can be kept constant even if the recording conditions (sensitivity of the optical recording medium and ambient temperature) change, enabling accurate tracking operation regardless of the presence or absence of the guide groove, and stable recording and reproduction Optical recording device can be obtained.

Here, the optical recording medium 8 and the optical pickup 1 shown in FIG. 1 may be relatively moved and scanned, and the optical recording medium 8 is fixed and the optical pickup 1 is moved in the scanning direction. You may. Although the main spot and the sub spot are generated using the diffraction grating, separate light sources may be used to correspond to each. The present apparatus is applicable to any type of optical recording medium as long as it can be recorded and reproduced by light. Although the focus control in the light spot scanning has not been described in the present embodiment, the description will be omitted because it is applicable if a known technique is used.

Embodiment 2 FIG. FIG. 5 shows the second embodiment. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts, and the description will be omitted. In the figure, reference numeral 31 denotes a photodetector for detecting a reflection projection image by the main spot 9, reference numeral 32 denotes a memory for storing a specified pit width as a time parameter in correspondence with a scanning speed, reference numeral 33 denotes a control unit, and reference numeral 34 denotes an output comparison And 35, a tracking servo unit.

FIG. 6 is a diagram showing the operation. This operation diagram is a diagram showing a pit width defining operation after recording the track 21. Since the operation of recording the track 21 is the same as that of the first embodiment, the description is omitted here. Reference numeral 36 denotes a locus of the main spot 9 (R) that scans the track 21. Here, the intensity of 9 (R) is, of course, the intensity at the time of reading the pit width, as described above. Control unit 33
The rotation position sensor 17 detects that the main spot 9 (R) reaches the area of the track 21. When reaching the track 21 area, the control unit 33 starts the tracking servo circuit 3
5 is given a wobbling signal. The tracking servo circuit 35 receives this signal and outputs a substantially sinusoidal drive current to the tracking actuator 5. This driving current causes the tracking actuator 5 to vibrate up and down. Therefore, the main spot 9 (R) moves along the track R in the direction of arrow R while wobbling on the track 21.
Becomes Since the amplitude of the tracking actuator 5 depends on the magnitude of the driving current output from the tracking servo circuit 35, a current value enough to cross the track 21 is set in advance.

Subsequently, the controller 33 controls the rotation position sensor 17
When the main spot 9 (R) reaches near the top of the track 21, the pit width is measured from the output of the photodetector 31. The operation at this time will be described with reference to the timing chart of FIG. With one rotation of the rotating rotor 7, the rotating position sensor 17 outputs an output once per cycle of the rotating rotor at a track start position (see S in FIG. 2). The control unit 33 outputs a wobbling signal to the tracking actuator 5 as described above, using the output of the rotational position sensor 17 as a trigger. Accordingly, the main spot 9 (R) starts wobbling, and the displacement of the main spot 9 (R) moves up and down across the reference position (0) as shown in the figure. Therefore, the main spot 9 (R) passes over the track 21 near the 0 position. Since the portion where the track 21 is formed has a lower reflectance than the other portions, the output of the photodetector 31 outputs the main spot 9 (R) every time the track 21 passes.
The signal becomes a low level signal only during the time t when the signal passes through the signal line 1. This time t is measured by the output comparison unit 34. The pit width obtained based on the time t is compared with a value of a specified pit width stored in advance as a time parameter in the memory 32. The comparison operation after this is the same as the operation described in the first embodiment, and the LD operation is performed until the pit width reaches the specified value.
The above comparison operation is repeatedly performed while changing the light amount of the above.

As described above, the formed track is scanned again while wobbling, and the optimum pit diameter can be formed from the output from the photodetector at that time.
Even if disturbance such as vibration occurs when measuring the pit width, the possibility of scanning any part of the track by the wobbling operation becomes very high, and the pit width can be detected with higher accuracy and stable auto tracking operation Becomes possible.

In this embodiment, the pit width is measured by assuming that the light spot is near the top of the track. However, the measurement may be performed at any point that crosses the track. Further, the rotation position sensor is assumed to output once in one cycle of the rotating rotor. However, an encoder that outputs a plurality of pulses with rotation may be used. In that case, the pulses are counted by the control unit and reach the track. You may recognize that.

Embodiment 3 Here, a further detailed embodiment of the relationship between the formed pit width and the light spot diameter and the tracking error signal will be described.
The basic configuration of the optical recording apparatus in this embodiment is as follows.
Since this is the same as FIG. 1 described above, reference is made thereto. As shown in FIG. 4, when the relationship between the pit width W and the light spot diameter D changes, the amount of light received by the photodetector 3 changes, and the detection output also changes. On the other hand, in tracking control, track deviation is detected by the division Da of the photodetector 4.
(Reference numeral 4a) and a tracking error signal (T based on the signal output detected by Db (reference numeral 4b).
Perform using E). Here, the signal TE is (da−db)
Is obtained by performing the following calculation. Therefore, if the ratio between the pit width W and the light spot diameter D is different, the detection characteristics of the signal TE are different. This is because the intensity of the reflected light other than at the pit forming portion is detected by the photodetector, and the LD light applied thereto has a Gaussian distribution whose intensity is higher at the center. FIG. 8 shows the TE detection characteristics obtained at that time. The horizontal axis is the track shift amount, and the vertical axis is the TE signal. Each characteristic curve has a ratio k (= pit width W and light spot diameter D).
(Pit width / light spot diameter). Since the linear zone of each characteristic curve is used for pulling in the tracking servo, it is desirable that the linear zone is wide. Although the linear zone becomes narrower as the ratio k increases, the linear zone also becomes narrower as the ratio k decreases. When the ratio k = 0.5, the linear zone becomes the widest. Therefore, it is desirable that the operation range of the auto tracking be within the range of 0.3 ≦ k ≦ 0.7. This value is stored in the memory as a reference value.

As described above, the pit width to be formed is defined with respect to the diameter of the light spot to be irradiated, so that a more accurate auto tracking operation can be performed.

The value stored in the memory is 0.3 ≦ k
If the range is ≦ 0.7, one point may be set, for example, k = 0.5, or the above range may be set as 0.4 <k <0.6, and the pit width may be set within this value. Alternatively, the recording / detection may be performed by repeatedly changing the LD light intensity.

Embodiment 4 FIG. FIG. 9 shows the fourth embodiment. In FIG. 9, reference numeral 40 denotes a track formed by the main spot 9 (W) for measuring a pit width;
Is a track on which the LD light intensity at that time is recorded. Note that the overall configuration of the optical recording apparatus according to this embodiment is the same as that of FIG. 1 or FIG. 5 described above, and a description thereof will not be repeated.

Next, the operation will be described. The operation for recording the track 40 to have the prescribed pit width is the same as in the first and second embodiments, and a description thereof will be omitted. When the rotating rotor 7 reaches the specified position of the track 41 by the rotation position sensor 17, the light intensity on the track 40 is converted into data (hereinafter, light intensity data),
A command signal and light intensity data are output to the output control unit 13 so as to be recorded in the portion of No. 1. The output control unit 13 modulates the output given to the LD 2 according to the light intensity data by the command signal, so that the LD light is modulated and the light intensity data is written in the track 41 area.

The LD written in the track 41 area
The light intensity data is used as described below when additionally writing on the recording medium 8. The track 40 is sought by the optical pickup 1. When there are a plurality of tracks, the track recorded last is sought. Next, the LD light intensity data of the track 41 recorded behind the track 40 is read into the control unit. Since this data is the LD light intensity when the pit width has reached the specified value, the control unit forms a track with this LD light intensity based on this data. A pit width detection operation is performed on the newly formed track.

As described above, in this embodiment, when a track defining the pit width is formed, the LD light intensity at that time is recorded.
Even if the time interval for the additional recording is long, the value is referred to as a measure of the LD light intensity at the time of the pit width defining operation, so that the time of the defining operation can be shortened. In addition, since changing the LD light intensity many times to create a track reduces the storage capacity of the recording medium 8, it is possible to perform the pit width defining operation without reducing the storage capacity as much as possible. Become.

In the present embodiment, the track for recording the LD light intensity at the time of recording is provided behind the pit width specified track in the scanning direction, but may be provided in front of the track.

Embodiment 5 FIG. FIG. 10 shows the fifth embodiment. In FIG. 10, reference numerals 42 and 43 denote LDs, respectively.
Tracks formed with different light intensities. Also in this embodiment, the overall configuration of the basic optical recording apparatus is the same as that of the above-described first embodiment shown in FIG.

Next, the operation will be described. First, LD
The light intensity is set to the output level α. With this setting output, the track 42 is recorded in the direction of arrow R. Next, the transport motor 19 is driven to transport the recording medium 8 by a predetermined distance to change the recording position. Next, the track 43 is formed by setting the LD light intensity to the output level β. At this time, the LD light intensities α and β have different values. Next, the transport motor 19
To return the storage medium 8 to the position where the track 42 is formed. The LD light intensity is set to the intensity at the time of reproduction, and the track 42
Is determined in the same manner as in the first embodiment. Next, the storage medium 8 is moved by the transport motor 19 and the track 43 is compared and determined. At this time, the control unit 12 stores the respective comparison determination results in the memory 11, and the light intensity for obtaining the predetermined pit width is smaller than α,
If it is larger than β, the intermediate value is set as the optimum recording light intensity, and the light intensity is set so as to record information.

As described above, since a plurality of tracks are formed in advance by using LD lights having different intensities, the LD light intensity for optimizing the pit width is obtained, so that the time required for obtaining the optimum light intensity is further reduced. And the operation can be shifted to the information recording operation promptly.

In this embodiment, the light intensity has two levels of α and β. However, the number of tracks corresponding to three levels or more may be formed. If the light intensity α level is optimum, it is needless to say that the next comparison of the light intensity β level need not be performed.

[0049]

According to the present invention, a light source for emitting light for recording and reproducing information on an optical recording medium, and a light spot formed on the optical recording medium by converging the light from the light source. A light converging means, a rotating means for rotating the light converging means, a control means for controlling the intensity of light emitted from the light source, and a light detecting means for detecting reflected light of the light spot from the optical recording medium. A memory means for storing a specified value of the pit width to be detected, and a comparing means for comparing a detection result from the light detecting means with a specified value of the memory means; After being formed on the optical recording medium by the spot, the light spot is irradiated on the track in the next scan, and the detection result from the light detection means at this time is compared with the specified value of the memory means by the comparison means,
Since the control means controls the pit width to be a specified value, the pit width can be kept constant even if various conditions (sensitivity of the optical recording medium and ambient temperature) at the time of track formation change. An accurate tracking operation can be performed even on an optical recording medium having no guide groove, and an effect that stable recording and reproduction can be performed can be obtained.

Further, since the light detecting means is composed of a plurality of divided sections for dividing the light spot into at least two or more divided areas and individually detecting each divided area, these divided sections are separated. Since the output result from is in inverse proportion to the pit width for the light spot, the output result can be used to set the pit width to the specified value for the light spot diameter, making it easy to control the pit width. It can be performed with high accuracy.

The apparatus further comprises tracking servo means for outputting a substantially sinusoidal drive current, and tracking actuator means for receiving the drive current and vibrating the rotation means up and down in response to the drive current. After the track for detecting the light spot is formed on the optical recording medium by the light spot, in the next scan, the light spot is irradiated on the track while wobbling, and the pit width is controlled from the output from the light detecting means at that time. Therefore, even if disturbance such as vibration occurs when measuring the pit width, the possibility of scanning any part of the track by wobbling operation is extremely high, and it is possible to detect the pit width with higher accuracy As a result, stable auto tracking operation becomes possible.

Further, since the specified value of the pit width is stored in the memory means as a time parameter corresponding to the scanning speed, it can be obtained from the time during which a certain place on the track is scanned by the wobbling operation. The pit width can be controlled with high accuracy by easily comparing the pit width with the prescribed value of the pit width stored as a parameter of time.

Further, the rotating means further includes a light beam splitting means for splitting the light from the light source into a plurality of beams, and after performing an operation of controlling the formed pit width to a specified value, Since the information is recorded and reproduced by the tracking method using multiple beams,
Even for an optical recording medium having no guide groove, stable high-precision tracking can be performed by light having an intensity controlled so that the pit width becomes a specified value.

Further, the prescribed value of the pit width is such that the ratio k (= pit width / light spot diameter) of the pit width to the light spot diameter is:
Since 0.3 ≦ k ≦ 0.7, the pit width to be formed is defined with respect to the light spot diameter, so that a more accurate auto-tracking operation can be performed.

Further, the track for defining the pit width and the track for recording data relating to the light intensity when the track is formed are formed on the optical recording medium. Even if is empty,
By referring to this value, it becomes a measure of the light intensity at the time of the pit width defining operation, so that the time of the pit width defining operation can be shortened. Furthermore, since creating a track by changing the light intensity many times reduces the storage capacity of the optical recording medium, it is possible to perform the pit width defining operation without reducing the storage capacity as much as possible. The effect is also obtained.

Further, since a plurality of tracks for defining the pit width are formed in advance by a plurality of light beams having different intensities, the time required for obtaining the optimum light intensity can be further reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an optical recording device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a pit width defining operation of the optical recording device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a recording / reproducing operation according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a principle of defining a pit width according to the first embodiment of the present invention;

FIG. 5 is a configuration diagram showing a configuration of an optical recording device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a pit width defining operation according to a second embodiment of the present invention.

FIG. 7 is a timing chart showing the operation of the second embodiment of the present invention.

FIG. 8 is a diagram showing a tracking error characteristic according to the third embodiment of the present invention.

FIG. 9 is a diagram showing a track configuration according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a pit width defining operation according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a conventional optical storage device.

FIG. 12 is a diagram showing tracks by a conventional optical storage device.

[Explanation of symbols]

1 optical pickup, 2 laser diode (LD),
3 main spot photodetector, 3a photodetector splitting section Sa,
3b photodetector dividing section Sb, 4 sub-spot photodetectors,
5 tracking actuator, 6 objective lens, 7
Rotating rotor, 8 recording media, 9 main spot, 10a
Sub spot, 11 memory, 12, 33 control unit, 1
3 output control unit, 14a output comparison unit, 14b output comparison unit, 17 rotation position sensor, 18 rotation motor, 21
truck.

Claims (8)

[Claims] 1. A light source for emitting light for recording and reproducing information on and from an optical recording medium, and a light focusing means for converging light from the light source to form a light spot on the optical recording medium. Rotating means for rotating the light focusing means; control means for controlling the intensity of the light emitted from the light source; light detecting means for detecting reflected light of the light spot from the optical recording medium; Memory means for storing a prescribed value of the pit width to be performed, and comparing means for comparing a detection result from the light detecting means with a prescribed value of the memory means. After the track is formed on the optical recording medium by the light spot, the light spot is irradiated on the track in the next scan, and the detection result from the light detection means at this time and the specified value of the memory means Optical recording apparatus is compared by the comparing means, the pit width to be formed and to control by the control means so that the above specified value. 2. The apparatus according to claim 1, wherein said light detecting means comprises a plurality of division sections for dividing said light spot into at least two or more divided areas and individually detecting each of said divided areas. The optical recording apparatus according to claim 1, wherein 3. A tracking servo means for outputting a substantially sinusoidal drive current; and a tracking actuator means to which the drive current is inputted and for vibrating the rotation means up and down in response to the drive current. 2. The method according to claim 1, further comprising: irradiating the track while wobbling the light spot in the next scan after a track for detecting a pit width is formed on the optical recording medium by the light spot. Optical recording device. 4. The optical recording apparatus according to claim 3, wherein the prescribed value of the pit width is stored in the memory as a time parameter corresponding to a scanning speed. 5. A light beam splitting means provided on the rotating means for splitting light from the light source into a plurality of beams, wherein the operation for controlling the formed pit width to be the specified value is performed. 5. The optical recording apparatus according to claim 1, wherein after performing the recording and reproducing of information by a tracking method using the plurality of beams. 6. The specified value of the pit width is such that the ratio k (= pit width / light spot diameter) of the pit width to the light spot diameter is:
6. The optical recording apparatus according to claim 1, wherein 0.3 ≦ k ≦ 0.7. 7. The optical recording medium according to claim 1, wherein a track defining a pit width and a track for recording data relating to the light intensity when the track is formed are formed on the optical recording medium. 7. The optical recording device according to any one of 6. 8. The optical recording apparatus according to claim 1, wherein a plurality of tracks defining a pit width are formed in advance by the light beams having different intensities.