JP2738617B2 - Optical recording / reproducing device - Google Patents

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 and reproducing information in parallel by irradiating a plurality of laser beams.

[0002]

2. Description of the Related Art Conventionally, as an optical recording / reproducing apparatus for recording or reproducing information in parallel by irradiating a plurality of laser beams, for example, there has been one disclosed in Japanese Patent Application Laid-Open No. 64-19535. FIG. 7 shows an optical path diagram of a conventional optical recording / reproducing apparatus, and shows only the parts related to the present invention extracted from FIGS. 1 and 3 (a) of the conventional example. In the figure, reference numeral 1 denotes an array type semiconductor laser which emits a plurality of laser beams, and the figure shows a laser which emits two laser beams 2 and 3. Reference numeral 4 denotes a collimator lens (a coupling lens in the above-described conventional example) for converting the laser beams 2 and 3 into a parallel light beam.
And a beam shaping prism 6 for converting the respective beam shapes of the laser beams 2 and 3 that have emitted the laser beam into a substantially perfect circle, and 6 are disposed so that the laser beams 2 and 3 that have emitted the beam shaping prisms are incident. Dove prism (wedge-shaped prism in the above conventional example), 7 is a dove prism 6
And a dove prism rotating mechanism for rotating the dove prism in the direction indicated by X in the drawing. Reference numeral 8 denotes an objective lens 9 (a narrowed-down lens in the above-described conventional example) which applies the laser beams 2 and 3 emitted from the dove prism 7 to the objective lens 9. This is a galvanomirror for allowing light to enter the lens, and can rotate in the direction indicated by Y in the figure. Reference numerals 2A and 3A denote condensed spots (light spots in the above conventional example) formed by condensing laser beams 2 and 3 by an objective lens, 10 denotes an information recording medium (disc in the above conventional example), and 11 denotes a condensed light. A target information track of the spot 2A, and 12 is a target information track of the focused spot 3A.

Next, the operation will be described. The laser beams 2 and 3 emitted from the array type semiconductor laser 1 pass through the collimator lens 4, the beam shaping prism 5, the galvanometer mirror 8, and the objective lens 9 and are irradiated as focused spots 2A and 3A on the surface of the information recording medium 10, respectively. Is done. Here, assuming that the focused spot 2A follows the information track 11 and the focused spot 3A follows the information track 12, information can be recorded and reproduced in parallel by the two laser beams 2 and 3. It is possible to improve the information recording speed. However, each condensed spot needs to accurately follow a predetermined information track. In the above-mentioned conventional example, this is realized by a method described below.

[0004] Focused spot 2A and focused spot 3A
The information recording medium 10 is rotated by the rotation of the galvanometer mirror 8.
It is displaced in a direction (Y direction) orthogonal to the direction in which the information tracks extend on the surface. Also, the direction of the spot row composed of the converging spot 2A and the converging spot 3A is
The information recording medium 10 is rotated by the dove prism rotating mechanism 7 in the direction (X direction) in which the information track extends on the surface of the information recording medium 10.

Therefore, first, the galvanomirror 8 is rotated to cause the condensed spot 2A to follow the target information track 11, and the dove prism 6 is rotated by the dove prism rotating mechanism 7 while maintaining this follow-up. By causing the light spot 3A to follow the target information track 12, it becomes possible for the converging spot 2A and the converging spot 3A to simultaneously follow the respective target information tracks 11 and 12 accurately at the same time. By such an operation, a plurality of condensed spots can be made to follow predetermined information tracks, respectively, so that parallel recording and reproduction can be performed, and the processing speed of information can be improved.

[0006]

In the conventional optical recording / reproducing apparatus as described above, as a method of causing a plurality of converging spots to follow a predetermined information track, a converging spot array is rotated with respect to the information track. The dove prism 6 is used as the rotating means. However, the method using the dove prism has the following disadvantages.

FIG. 8 is a plan view showing an example of a dove prism 6 used in a conventional optical recording / reproducing apparatus. For example, when a glass material having a refractive index of 1.5 is used, the size of the upper base is 18 mm, the lower base is 34 mm, and the height and the thickness are about 8 mm. Therefore, the first disadvantage is that the length of the dove prism itself is long, and it is difficult to reduce the size of the optical path system.

The second disadvantage is that the weight of the dove prism 6 itself is heavy. The volume is calculated from the shape of FIG. 8, and the specific gravity of the glass is set to 2.5, and the weight is calculated to be 4.2 g. With the dove prism 6 having such a weight, it is difficult to rotate at a high frequency, which causes a problem that it is impossible to accurately follow each focused spot on a predetermined information track. Further, in order to rotate the dove prism 6 at a high frequency, a large driving force is required for the rotating mechanism, and there is a problem that the optical recording / reproducing apparatus becomes large and expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the inventions of claims 1 and 2 use a small and lightweight optical component to make each condensed spot a predetermined information track. It is an object of the present invention to obtain an optical recording / reproducing apparatus capable of accurately following the optical recording / reproducing method.

According to the third and fourth aspects of the present invention, there is provided an optical recording / reproducing apparatus capable of causing each converging spot to accurately follow a predetermined information track by using an optical component constituting a conventional optical recording / reproducing apparatus. It is intended to be.

A fifth object of the present invention is to provide a method of controlling a focused spot, which enables each focused spot to accurately follow a predetermined information track.

[0012]

According to the first aspect of the present invention, there is provided an optical recording / reproducing apparatus comprising: a light source for emitting a plurality of laser beams;
Convert the laser beam emitted from the light source into a parallel light beam
Collimator lens, converges the collimated laser beam
To form multiple converging spots on the information recording medium surface
An objective lens, and the plurality of condensed spots are
Irradiation on different information tracks of recording media
An optical recording / reproducing device that records or reproduces information
The optical path between the collimator lens and the objective lens
Sufficient compared to the focal length of the objective lens placed inside
A long focal length lens and this lens
And move it back and forth in the direction of the optical axis so that the lens spacing changes.
And the distance between the converging spots and the information
Control to match the spacing of information tracks on recording media
By performing the above, each of the plurality of focused spots
A track for following a predetermined information track on an information recording medium.
And a pot control means .

An optical recording / reproducing apparatus according to a second aspect of the present invention comprises:
A light source for emitting a plurality of laser beams;
Collimator to convert a laser beam into a parallel beam
And converges the parallel beam of laser beams to form an information recording medium.
An objective lens that forms multiple converging spots on the body surface
And having the plurality of condensed spots different from each other on the information recording medium.
To irradiate the information track in parallel to record information in parallel.
In an optical recording / reproducing apparatus for performing
Disposed in the optical path between the data lens and the objective lens.
A relay lens and this relay lens
Move back and forth in the direction of the optical axis to change the lens spacing
Drive means, and the information recording of the distance between the condensed spots.
Control to match the information track spacing of the medium
By doing so, each of the plurality of condensed spots is
To follow a predetermined information track on the information recording medium.
And a cut control means .

An optical recording / reproducing apparatus according to a third aspect of the present invention comprises:
A light source for emitting a plurality of laser beams;
Collimator to convert a laser beam into a parallel beam
And converges the parallel beam of laser beams to form an information recording medium.
An objective lens that forms multiple converging spots on the body surface
And having the plurality of condensed spots different from each other on the information recording medium.
To irradiate the information track in parallel to record information in parallel.
In an optical recording / reproducing apparatus for performing
The distance between the lens and the objective lens changes.
Drive means for moving back and forth in the direction of the optical axis;
Set the spot interval between the information tracks on the information recording medium.
By performing control to match the distance,
The number of light-condensing spots is determined by the predetermined information of the information recording medium.
And a spot control means for following the track .

An optical recording / reproducing apparatus according to a fourth aspect of the present invention comprises:
A light source for emitting a plurality of laser beams;
Collimator to convert a laser beam into a parallel beam
And converges the parallel beam of laser beams to form an information recording medium.
An objective lens that forms multiple converging spots on the body surface
And having the plurality of condensed spots different from each other on the information recording medium.
To irradiate the information track in parallel to record information in parallel.
Or an optical recording / reproducing apparatus for performing reproduction,
A driving means for moving back and forth in the direction of the optical axis;
The distance between the pots is the distance between the information tracks on the information recording medium.
By performing control to match
Of each of the condensed light spots of the information recording medium.
Spot control means for following the rack .

An optical recording / reproducing apparatus according to a fifth aspect of the present invention comprises:
An optical recording / reproducing apparatus according to any one of claims 1 to 4,
At least one of the above condensed spots
Means for detecting a focusing error signal;
Tracking error signal from at least two of the
And the spot control means.
(1) Based on the focusing error signal,
(2) The above two traps
The tracking error based on one of the king error signals.
The first focusing spot for detecting the error signal is focused on the focusing spot.
Positioning on the target first information track of the pot,
(3) Pausing the focusing operation according to (1) above,
(4) The other of the two tracking error signals
A second method for detecting the tracking error signal based on
Second information for making the light spot a target of the light spot
Operation of the drive means to be positioned on the track,
(5) Release of suspension by (3) above, (6)
If the objective lens is based on the focusing error signal,
Or by driving both the objective lens and the lens
Multiple spots that sequentially repeat focusing and focusing of the focused spot
This is provided with a packet control means .

[0017]

According to the first aspect of the present invention, the distance between the condensed spots on the information recording medium surface changes by displacing the lens provided between the collimator lens and the objective lens in the optical axis direction. .

According to the second aspect of the present invention, one of the relay lenses provided between the collimator lens and the objective lens is displaced in the direction of the optical axis, so that each of the condensed spots on the information recording medium surface is displaced. The spot interval changes.

According to the third aspect of the present invention, by displacing the collimator lens in the direction of the optical axis, the spot interval of each condensed spot on the information recording medium surface changes.

According to the fourth aspect of the present invention, by displacing the array type semiconductor laser in the optical axis direction, the spot interval of each condensed spot on the information recording medium surface changes.

According to the fifth aspect of the present invention, the focusing operation of each focused spot is first performed by the spot control means based on the focusing error signal, and then the focused spot is controlled based on the tracking error signal from one focused spot. And the converging spots respectively follow the predetermined information track of the information recording medium based on the other tracking error signal.

[0022]

【Example】

Embodiment 1 FIG. Hereinafter, Embodiment 1 of the optical recording / reproducing apparatus of the present invention will be described.
Will be described with reference to the drawings. FIG. 1 is an optical path diagram showing the configuration of the first embodiment.
Is the same as However, the array type semiconductor laser 1 emits five laser beams 13. In the emission direction of the collimator lens 4, a beam splitter 14, a lens 15, and an objective lens 9 are sequentially arranged.

Reference numeral 16 denotes a lens driving mechanism for displacing the lens 15 in the optical axis direction. Reference numeral 17 denotes a focusing drive mechanism for displacing the objective lens 9 in the optical axis direction. 18 is a tracking drive mechanism for displacing in the direction perpendicular to the direction information track of the information recording medium 10 through the objective lens 9 extends, but it may be used galvanomirror as shown in Figure 7.

Reference numeral 19 denotes a converging lens for converging the laser beam 13 reflected on the information recording medium 10. 20
Is a beam splitter for splitting the laser beam 13 emitted from the converging lens in two directions. Reference numeral 21 denotes a knife edge for transmitting the five laser beams 13 transmitted through the beam splitter 20, transmitting only about half of the light beam of one laser beam before the focal point, and shielding all the remaining laser beams 13. is there.

Reference numeral 22 denotes a two-part photodetector having two light receiving surfaces arranged so as to receive the laser beam not blocked by the knife edge 21 at the focal point. Reference numerals 23 to 27 denote photodetectors arranged so as to detect the five laser beams 13 reflected from the beam splitter 20 at two positions other than the focal points thereof, with the two light receiving surfaces. Reference numeral 28 denotes a differential amplifier for obtaining a subtraction signal from two output signals of the split photodetector 22.

Reference numeral 29 denotes a focusing servo circuit to which the output signal of the differential amplifier 28 is input, and the focusing drive mechanism 17 is connected to the subsequent stage. Reference numerals 30 to 34 denote adders for obtaining an addition signal from the two output signals of the two-divided photodetectors 23 to 27, respectively. Reference numeral 35 denotes a differential amplifier for obtaining a subtraction signal from two output signals of the split photodetector 23. 36 is a two-segment photodetector 27
Is a differential amplifier for obtaining a subtraction signal from the two output signals.

Reference numeral 37 denotes a first tracking servo circuit to which the output signal of the differential amplifier 35 is input, and the tracking drive mechanism 18 is connected to a subsequent stage. Reference numeral 38 denotes a second tracking servo circuit to which an output signal of the differential amplifier 36 is input, and a lens driving mechanism 16 is connected to a subsequent stage. Reference numeral 39 denotes an input of the output signals of the differential amplifiers 28, 35, 36, and a focusing servo circuit 29,
The control circuit outputs different control signals to the tracking servo circuit 37 and the second tracking servo circuit 38 of FIG.

Next, the operation will be described with reference to FIGS. FIG. 2 is a plan view showing the operation of the lens and the positional relationship between the converging spot and the information track on the information recording medium in this embodiment, and shows only those parts necessary for the explanation. In the figure, reference numerals 40 and 41 denote laser beams at both ends of the laser beam 13 shown in FIG.
Reference numerals 0A and 41A denote condensed spots of the laser beams 40 and 41, respectively. Reference numeral 42 denotes a target information track of the condensing spot 40A, and reference numeral 43 denotes a target information track of the condensing spot 41A. FIG. 3 is a flowchart showing the operation of following a converging spot.

FIG. 2A shows the condensed light spots 40A and 41A.
Indicate that the information tracks 42 and 43 are correctly following the respective target information tracks 42 and 43. In such a case, information can be recorded or reproduced in parallel at each of the condensing spots. However, a case may occur in which the interval between the converging spots 40A and 41A is not equal to the interval between the information tracks 42 and 43.

FIG. 2B shows a case where the distance between the converging spots 40A and 41A is smaller than the distance between the information tracks 42 and 43. In such a case, the lens 1
5 is displaced in the direction of the optical axis.
It is possible to match the 41A spacing between septa information tracks 42 and 43 and.

In FIG. 2C, the lens 15 is connected to the objective lens 9.
The case where the distance between the converging spots 40A and 41A can be increased when the distance is approached. However, with the displacement of the lens 15, the focal spot position in the optical axis direction, that is, the focal position also moves at the same time. In the example of FIG. 2C, the information recording medium 10 is closer than the focal length of the objective lens 9. It is located in.

Therefore, as shown in FIG. 2D, the focus position can be corrected by simultaneously moving the objective lens 9 and the lens 15 away from the information recording medium 10 while maintaining the distance between the objective lens 9 and the lens 15. The convergent spot 40A can correctly follow the information track 42, and the convergent spot 41A can correctly follow the information track 43.

However, if the focal length of the lens 15 is sufficiently large with respect to the focal length of the objective lens 9, the focal position can be corrected by moving only the objective lens 9 away from the information recording medium 10 in the state of FIG. It is. On the other hand, when the interval between the converging spots is larger than the interval between the information tracks, the operation opposite to the above operation may be performed.

The following operation of following the converging spot is described in FIG.
This will be described with reference to the flowchart of FIG. At the start 44 of the control of the focused spot, first, a focusing servo start 45 is performed. The focusing servo is a known knife-edge focusing sensor composed of a knife edge 21, a two-part photodetector 22, and a differential amplifier 28 using at least one of the five laser beams 13 shown in FIG. The focus position of the condensed spot is detected by the method, and the focusing servo circuit 29 operates the focusing drive mechanism 17 according to the amount of defocus, so that the condensed spot formed by the objective lens 9 is always recorded on the information recording medium 10. Focus on above.

If the focused spot is the focal point 46, then a first tracking servo start 47 is performed.
The tracking servo uses a laser beam at one end of the five laser beams 13 shown in FIG. 1 to condense by a known push-pull tracking sensor system including a two-divided photodetector 23 and a differential amplifier 35. The tracking error of the spot is detected, and the first tracking servo circuit 37 operates according to the amount of the tracking error.
By operating 8, the focused spot formed by the objective lens 9 is always displayed on the information track of the information recording medium 10. With this operation, the condensed spot in the laser beam at one end of the five laser beams 13 can correctly follow the target information track.

The condensed spot on one end is located on the information track 48.
If so, the focusing servo hold 49 is performed next. This is to temporarily stop the focusing operation of the objective lens 9, and the focusing servo circuit is temporarily stopped by an instruction of the control circuit 39.

With the focusing servo held, a second tracking servo start 50 is performed. As in the case of the first tracking servo, a known push-pull method including a split photodetector 27 and a differential amplifier 36 using a laser beam at the other end of the five laser beams 13 shown in FIG. The tracking sensor system detects a tracking shift of the condensed spot at the other end, and the second tracking servo circuit 38 operates the lens driving mechanism 15 in accordance with the shift amount, and as shown in FIG. Is made to coincide with the information track interval by the displacement in the optical axis direction. In this operation, all five condensed spots are located on the target information track.

The condensing spot at the other end is located on the information track 51.
If so, the hold of the focusing servo is released 52 next. When the hold is released, the process returns to the focusing servo start 45, and as shown in FIG. 2D, the objective lens 9 is displaced by the focusing servo circuit so that all the focused spots on the information recording medium 10 are focused. Close. As described above, if the focal length of the lens 15 is sufficiently larger than that of the objective lens 9, only the objective lens 9 may be displaced, or both of them may be maintained while maintaining the distance between the lens 15 and the objective lens 9. The lenses may be displaced simultaneously. By this operation, all five condensed spots can correctly follow the target information track.

As a result, information is recorded or reproduced in parallel at each of the condensed spots, and each reproduced signal is detected as an output signal from the adders 30 to 34.

The control circuit 39 includes two split photodetectors 28, 3
The focusing and tracking servo circuits are controlled based on the output signals from 5 and 36 to execute the above-described operations.

In FIG. 1, the knife edge method is shown as the focusing sensor method, but another method may be used. Alternatively, detection may be performed using one or more other laser beams instead of the laser beam at one end.

Although the push-pull method is shown in FIG. 1 as the tracking sensor method, another method may be used. Further, the detection may be performed using another laser beam instead of the laser beams at both ends.

Driving mechanism 16 for lens 15 and objective lens 9
Focusing and tracking drive mechanisms 17, 18
May be any type, and does not limit the method.

Embodiment 2 FIG. FIG. 4 is an optical path diagram showing a second embodiment of the present invention, wherein reference numerals 1, 4, 9, 10, 13, 14
Are the same as those in FIG. Reference numerals 53 and 54 denote relay lenses disposed in the optical path between the collimator lens 4 and the objective lens 9, and reference numeral 55 denotes one of the relay lenses 53 and 54 (the objective lens 9 side in FIG. 4) in the optical axis direction. This is a relay lens drive mechanism for moving the lens back and forth. In the case of this embodiment, as in the case of the lens 15 of FIG.
The distance between the information tracks of the information recording medium 10 can be matched.

Embodiment 3 FIG. FIG. 5 is an optical path diagram showing a third embodiment of the present invention, and reference numerals 1, 4, 9, 10, 13, 14
Are the same as those in FIG. 56 is a collimator lens 4
Is a collimator lens driving mechanism for driving the lens back and forth in the optical axis direction. In the case of this embodiment, by displacing the collimator lens 4 in the optical axis direction as in the case of the lens 15 of FIG. 1, the interval between the condensed spots can be matched with the information track interval of the information recording medium 10.

Embodiment 4 FIG. FIG. 6 is an optical path diagram showing a fourth embodiment of the present invention, and reference numerals 1, 4, 9, 10, 13, 14
Are the same as those in FIG. Reference numeral 57 denotes a laser drive mechanism for driving the array type semiconductor laser 1 back and forth in the optical axis direction. In the case of this embodiment, by displacing the array-type semiconductor laser 1 in the optical axis direction in the same manner as the lens 15 in FIG. 1, the interval between the condensed spots can be matched with the information track interval on the information recording medium 10. .

[0047]

As described above, according to the first aspect of the present invention, a light source for emitting a plurality of laser beams,
A collimator that converts the emitted laser beam into a parallel beam
Information recording by converging the parallel laser beam
An objective lens that forms multiple converging spots on the medium surface
And the plurality of condensed spots are different from each other in the information recording medium.
Irradiate on the information track to record information in parallel
Or in an optical recording / reproducing apparatus for performing reproduction,
Disposed in the optical path between the meter lens and the objective lens.
Focal length sufficiently longer than the focal length of the objective lens
Lens and the distance between this lens and the objective lens
Drive means for moving back and forth in the direction of the optical axis so that
And the distance between the converging spots and the information on the information recording medium.
To control to match the track interval
The plurality of condensed spots can be respectively assigned to the information recording medium.
Spot control hand to follow the specified information track
By providing a step, instead of rotating the dove prism, the lens disposed in the optical path between the collimator lens and the objective lens is displaced in the direction of the optical axis, and the distance between the condensed spots is changed, so that the information track is changed. , The light-weight lens can be driven back and forth at a high frequency as compared with the dove prism, so that each converged spot can be accurately followed on a predetermined information track. .

According to the second aspect of the present invention, a plurality of laser
Light source for emitting a beam, laser beam emitted from the light source
A collimator lens that converts
The laser beam is converged to collect multiple
An objective lens for forming a light spot;
Light spots on different information tracks of the information recording medium
To record or reproduce information in parallel
In the optical recording / reproducing apparatus, the collimator lens and the
A relay lens arranged in the optical path between the objective lenses,
The distance between this relay lens and the objective lens changes
Drive means for moving back and forth in the direction of the optical axis
The distance between the condensed light spots should be
By controlling so that it matches the interval of the
Each of the plurality of condensed spots is defined by a predetermined
Spot control means to follow the information track of
By disposing, instead of rotating the dove prism, the relay lens disposed in the optical path between the collimator lens and the objective lens is displaced in the direction of the optical axis, and the distance between the condensed spots is changed, thereby changing the distance between the information tracks. , It is possible to drive the relay lens, which is lighter than the dove prism, back and forth at a high frequency, so that each converging spot can be accurately followed on a predetermined information track.

According to the third aspect of the present invention, a plurality of laser
Light source for emitting a beam, laser beam emitted from the light source
A collimator lens that converts
The laser beam is converged to collect multiple
An objective lens for forming a light spot;
Light spots on different information tracks of the information recording medium
To record or reproduce information in parallel
In the optical recording / reproducing apparatus, the collimator lens is
Forward in the direction of the optical axis so that the distance between the objective lens and the lens changes.
The distance between the driving means for moving back and the focused spot
Match the distance between the information tracks on the information recording medium
The above-mentioned plurality of condensed spots
Follow the specified information track of the information recording medium
By providing the spot control means to make it possible, instead of rotating the dove prism, the collimator lens is displaced in the direction of the optical axis, and the interval between the condensed spots is varied to match the interval between the information tracks, This makes it possible to drive a relay lens, which is lighter than a dove prism, back and forth at a high frequency, and to follow each information spot accurately on a predetermined information track without increasing the number of optical components.

According to the fourth aspect of the present invention, a plurality of laser
Light source for emitting a beam, laser beam emitted from the light source
A collimator lens that converts
The laser beam is converged to collect multiple
An objective lens for forming a light spot;
Light spots on different information tracks of the information recording medium
To record or reproduce information in parallel
In the optical recording / reproducing apparatus, the light source is moved back and forth in the direction of the optical axis.
Increase the distance between the drive means to be moved and the focused spot.
The distance between the information tracks on the information recording medium.
By controlling as described above, it is possible to
Follow each predetermined information track of the information recording medium.
By providing the spot control means for tightening , instead of rotating the dove prism, the array type semiconductor laser is displaced in the optical axis direction, and the interval between the converging spots is changed to match the interval between the information tracks. Therefore, compared to a dove prism, it is possible to drive a light-weight array type semiconductor laser back and forth at a high frequency, and it is also possible to accurately follow each focused spot on a predetermined information track without increasing the number of optical components. There is.

According to the invention of claim 5, according to claims 1 to
5. The optical recording and reproducing apparatus according to claim 4, wherein
Focusing error from at least one of the light spots
Means for detecting a signal;
Means for detecting the tracking error signal from the two
And the spot control means (1)
Based on the focusing error signal,
Focusing (2) The above two tracking error signals
Detecting the tracking error signal based on one of the
The first focused spot to be emitted is set as the target of the focused spot.
(3) The above (1)
(4) The above two triggers
The tracking error is determined based on the other one of the racking error signals.
A second focused spot for detecting a king error signal is collected.
Position on the target second information track of the light spot
(5) As described in (3) above,
(6) Focusing error described above
The objective lens or the objective lens based on the signal
Of the focused spot by driving both the lens and the lens
Since a plurality of spot control means for sequentially repeating point alignment are provided, there is an effect that each converged spot can accurately follow a predetermined information track of the information recording medium.

[Brief description of the drawings]

FIG. 1 is an optical path diagram of Embodiment 1 of the present invention.

FIG. 2 is an optical path diagram illustrating an operation of spot control in the first embodiment.

FIG. 3 is a flowchart illustrating an operation of spot control according to the first embodiment.

FIG. 4 is an optical path diagram according to a second embodiment of the present invention.

FIG. 5 is an optical path diagram according to a third embodiment of the present invention.

FIG. 6 is an optical path diagram according to a fourth embodiment of the present invention.

FIG. 7 is an optical path diagram of a conventional optical recording / reproducing apparatus.

FIG. 8 is a plan view of a dove prism applied to a conventional optical recording / reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Array type semiconductor laser 4 Collimator lens 9 Objective lens 10 Information recording medium 13 Laser beam 15 Lens 16 Lens drive mechanism 17 Focusing drive mechanism 18 Tracking drive mechanism 22 Two-part photodetector 23 Two-part photodetector 27 Two-part photodetector Reference Signs List 28 Differential amplifier 29 Focusing servo circuit 35 Differential amplifier 36 Differential amplifier 37 First tracking servo circuit 38 Second tracking servo circuit 39 Control circuit 40 Laser beam 40A Focusing spot 41 Laser beam 41A Focusing spot 42 Focusing Target information track of spot 40A 43 Target information track of condensing spot 41A 53 Relay lens 54 Relay lens 55 Relay lens drive mechanism 56 Collimator lens drive mechanism 57 Array type semiconductor laser The drive mechanism

 ──────────────────────────────────────────────────の Continuation of the front page (72) The inventor, Manabu Koike, 1 Baba Zujo, Nagaokakyo-shi, Kyoto, Japan Inside the Electronic Product Research Laboratory, Mitsubishi Electric Corporation (56) References JP-A-64-19535 (JP, A) JP-A-3-183027 (JP, A) JP-A-2-68722 (JP, A) JP-A-62-266429 (JP, A)

Claims (5)

(57) [Claims] 1. A light source for emitting a plurality of laser beams, a collimator lens for converting the laser beam emitted from the light source into a parallel light beam, and a plurality of light beams converging on the surface of the information recording medium by converging the parallel laser beam. An optical recording and reproducing apparatus having an objective lens for forming a spot and irradiating the plurality of focused spots on different information tracks of the information recording medium to record or reproduce information in parallel, wherein the collimator lens and A lens having a focal length sufficiently longer than the focal length of the objective lens disposed in the optical path between the objective lenses, and
And drive means for moving back and forth in the direction of the optical axis so that the distance between the lenses is changed, the condensing spot interval the information recording of
Control to match the spacing of information tracks on recording media
By performing the above, each of the plurality of focused spots
An optical recording / reproducing apparatus , comprising : spot control means for following a predetermined information track on an information recording medium . 2. A light source for emitting a plurality of laser beams, a collimator lens for converting the laser beam emitted from the light source into a parallel light beam, and a plurality of light beams converging on the surface of the information recording medium by converging the parallel laser beam. An optical recording and reproducing apparatus having an objective lens for forming a spot and irradiating the plurality of focused spots on different information tracks of the information recording medium to record or reproduce information in parallel, wherein the collimator lens and a relay lens disposed in the optical path between the objective lens, on the relay lens
Driving means for moving the objective lens and the lens back and forth in the direction of the optical axis so as to change the distance between the objective lens and the focusing spot;
To the interval between the information tracks on the information recording medium.
By performing control in such a way as to
Each track on a predetermined information track of the information recording medium.
An optical recording / reproducing apparatus , comprising: a spot control unit for causing the optical recording / reproducing apparatus to follow . 3. A light source for emitting a plurality of laser beams, a collimator lens for converting the laser beam emitted from the light source into a parallel light beam, and a plurality of light beams converging on the information recording medium surface by converging the parallel laser beam. An objective lens for forming a spot, and irradiating the plurality of condensed spots on different information tracks of the information recording medium to record or reproduce information in parallel; Between the objective lens and the lens
Driving means for moving back and forth in the direction of the optical axis so as to change the distance;
Control to match the information track interval
The plurality of condensed spots are respectively
An optical recording / reproducing apparatus , comprising: spot control means for following a predetermined information track of a body . 4. A light source for emitting a plurality of laser beams, a collimator lens for converting the laser beam emitted from the light source into a parallel light beam, and a plurality of light beams converging on the information recording medium surface by converging the parallel laser beam. An objective lens for forming a spot, and irradiating the plurality of converging spots on different information tracks of the information recording medium to record or reproduce information in parallel; drive means for moving back and forth in the direction of the axis, the information of the information recording medium a distance of the condensing spot
To control to match the track interval
The plurality of condensed spots can be respectively assigned to the information recording medium.
An optical recording / reproducing apparatus , comprising: a spot control means for causing a spot to follow a predetermined information track . 5. The optical recording / reproducing apparatus according to claim 1, wherein a means for detecting a focusing error signal from at least one of the converging spots is provided.
Means for detecting a tracking error signal from at least two of the converging spots, wherein the spot control means (1) focuses the converging spot based on the focusing error signal; A first focus spot for detecting the tracking error signal based on one of the two tracking error signals is positioned on a target first information track of the focus spot; (3) According to the above (1) (4) A second information track that targets a second condensed spot for detecting the tracking error signal based on the other of the two tracking error signals, based on the other of the two tracking error signals. (5) Release of the temporary stop by (3) above, (6) Focusing error Optical recording and reproducing apparatus characterized by comprising a plurality spots control means sequentially repeating focusing, of the focused spot due to the driving of both the objective lens or the objective lens and the lens based on the signal.