JP3614350B2 - Optical head device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical head device that emits multi-beam laser light and detects return light, and more particularly to an optical head device that can control the positions of focal spots of a large number of laser beams.
[0002]
[Prior art]
With increasing density and capacity of optical discs, techniques for recording / reproducing optical information at high speed on optical discs are required.
For this reason, in recent years, techniques for recording / reproducing information in parallel using a plurality of laser beams have been developed.
[0003]
As a technique for recording / reproducing optical information using such a plurality of laser beams (multi-beams), an optical pickup using a surface emitting laser (VCSEL; Vertical Cavity Surface Emission Laser) is considered. For example, “Basic and Application of Surface Emitting Laser”, edited by Kenichi Iga and edited by Fumio Koyama, edited by Kyoritsu Publishing Co., Ltd., page 202, presents the idea of an optical pickup using a surface emitting laser.
[0004]
[Problems to be solved by the invention]
When recording / reproducing information to / from a recording medium such as an optical disk using a surface emitting laser as described above, the position of the focal spot formed by each of a plurality of laser beams emitted from the surface emitting laser is appropriately set. The technology to control is required.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical head device capable of appropriately controlling the positions of focal spots of a large number of laser beams.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an optical head device according to a first aspect of the present invention provides:
An optical head array comprising a plurality of light emitting elements for emitting multi-beam laser light corresponding to a plurality of tracks on the optical disc, and a plurality of photodetectors for detecting return light from the optical disc;
A lens array in which a plurality of objective lenses for condensing the laser beams emitted from the plurality of light emitting elements on the optical disc are arranged;
At least two support means for adjustably supporting a distance between the optical head array and the lens array;
A second signal created based on a first signal sent from one of the plurality of photodetectors installed close to the support means is applied to the corresponding support means, and the optical head At least two spot control means for controlling the position of the focal spot of the laser light emitted from the plurality of light emitting elements by adjusting the distance between the array and the lens array;
It is characterized by that.
[0007]
According to the present invention, the at least two support means support the distance between the optical head array and the lens array so as to be adjustable. The at least two spot control means generates a second signal based on a first signal sent from a plurality of photodetectors provided in the optical head array, which are installed in proximity to each support means, Applied to the corresponding support means, the distance between the optical head array and the lens array is adjusted.
Thereby, the position of the focal spot of the laser beam emitted from the plurality of light emitting elements included in the optical head array can be appropriately controlled.
[0008]
Each of the support means includes, at one end, a movable portion that can move a connection position with the semiconductor substrate on which the optical head array is installed,
Further, each of the support means changes the position of the lens array by moving the movable portion to move the connection position with the semiconductor substrate in accordance with the second signal applied by the corresponding spot control means. It is desirable to adjust the distance between the optical head array and the lens array.
[0009]
Alternatively, each of the support means includes, at one end, a movable portion that can move a connection position with the semiconductor substrate to which the lens array is fixed.
Further, each of the support means changes the position of the optical head array by moving the connection position of the movable part with the semiconductor substrate in accordance with the second signal applied by the corresponding spot control means. Then, the distance between the optical head array and the lens array may be adjusted.
[0010]
In addition, a tracking error signal generated based on a signal group sent from a quadrant photodetector included in the plurality of photodetectors is applied to the support means, and the positions of the support means are the same in the radial direction of the optical disc. You may provide the tracking control means to move only the quantity.
[0011]
An optical head device according to a second aspect of the present invention is
An optical head array comprising a plurality of light emitting elements for emitting multi-beam laser light corresponding to a plurality of tracks on the optical disc, and a plurality of photodetectors for detecting return light from the optical disc;
A lens array in which a plurality of objective lenses for condensing laser light emitted from the plurality of light emitting elements on the optical disc are arranged, the distance between the optical head array is fixed and fixed;
At least two support means for adjusting the distance between the optical head array and the lens array, and the optical disc;
The optical head is configured to apply a second signal generated based on a first signal sent from one of the plurality of photodetectors installed close to the support means to the corresponding support means. And at least two spot control means for controlling the position of the focal spot of the laser light emitted from the plurality of light emitting elements by adjusting the distance between the array and the lens array and the optical disc,
It is characterized by that.
[0012]
According to the present invention, the at least two supporting means support the distance between the optical head array and the lens array and the optical disk so as to be adjustable. The at least two spot control means generates a second signal based on a first signal sent from a plurality of photodetectors provided in the optical head array, which are installed in proximity to each support means, Applied to the corresponding support means, the distance between the optical head array and lens array and the optical disk is adjusted.
Thereby, the position of the focal spot of the laser beam emitted from the plurality of light emitting elements included in the optical head array can be appropriately controlled.
[0013]
A tracking error signal generated based on a signal group sent from a quadrant photodetector included in the plurality of photodetectors is applied to each of the support means, and the position of each of the support means is the same amount in the radial direction of the optical disc. You may provide the tracking control means to move.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an optical head device 100 according to an embodiment of the present invention will be described in detail with reference to the drawings.
[0017]
An optical head device 100 according to an embodiment of the present invention is provided at the tip of an arm 110 as shown in FIG. 1, for example, for recording optical information on an optical disc OD and reading out optical information recorded on the optical disc OD. belongs to.
Here, the arm 110 functions as a holding spring that urges the optical head device 100 installed at the tip in the direction of the optical disk OD, and utilizes the thin film gas lubrication caused by the rotation of the optical disk OD, thereby using the optical head device 100. Is held close to the optical disc OD.
[0018]
FIG. 2 is a perspective view for explaining the configuration of the optical head device 100.
As shown in the figure, the optical head device 100 includes an optical head array 10, two support parts 12 a and 12 b provided with movable parts 11 a and 11 b at one end thereof, and a lens array 13. The optical head device 100 includes a circuit layer 20 on which an operational amplifier circuit having servo circuits 15a, 15b and the like is formed, a semiconductor substrate 21, and a protective layer 22.
[0019]
FIG. 3A is a side view illustrating the positional relationship among the optical head array 10, the support portions 12a and 12b, and the lens array 13, and FIG. 3B shows the arrangement of the optical head array 10 and the movable portion 11a. 11b is a top view showing the arrangement of the movable regions 11b.
[0020]
The optical head array 10 is composed of a surface emitting laser (VCSEL; Vertical Cavity Surface Emitting Laser) or the like, and emits multi-beam laser light from the substrate surface. The optical head array 10 includes a plurality of light emitting elements 10 a to 10 d that can emit laser light in a direction perpendicular to the surface of the semiconductor substrate 21. The optical head array 10 has a plurality of light emitting elements 10 a to 10 d integrated two-dimensionally on a semiconductor substrate 21.
Here, the optical head array 10 is arranged such that each of the light emitting elements 10a to 10d emits laser light corresponding to different tracks of the optical disc OD. That is, the laser beams emitted from the plurality of light emitting elements 10a to 10d are respectively irradiated on different tracks on the optical disc OD.
Further, as shown in FIG. 3B, the optical head array 10 detects the return light reflected by the optical disc OD by the laser light emitted from each of the light emitting elements 10a to 10d, and thus a plurality of photodetectors 14a to 14d. It has.
[0021]
The movable portions 11a and 11b are configured using piezo elements or the like, and are microactuators to which, for example, MEMS (Micro-Electro-Mechanical System) technology is applied. That is, the movable portions 11a and 11b change in shape due to distortion caused by the focus error signals FE1 and FE4, which are voltage signals applied from the circuit provided in the circuit layer 20 through the semiconductor substrate 21, and the semiconductor substrate. The contact position with 21 can be changed within a predetermined movable region.
[0022]
The support portions 12 a and 12 b are configured integrally with the lens array 13 and are for connecting the lens array 13 to the semiconductor substrate 21. The support portions 12a and 12b are provided with movable portions 11a and 11b, respectively, at the connection portions with the semiconductor substrate 21, and the positional relationship between the optical head array 10 and the lens array 13 is changed by moving the contact position with the semiconductor substrate 21. Stipulate. Accordingly, the support portions 12a and 12b can hold the lens array 13 at a position where the multi-beam laser light emitted from the optical head array 10 is appropriately irradiated to the track of the optical disc OD.
[0023]
The lens array 13 is composed of a plurality of objective lenses arranged corresponding to the respective light emitting elements 10a to 10d, and the focal spot of the multi-beam laser light emitted from each of the light emitting elements 10a to 10d of the optical head array 10 is obtained. Adjust and collect light, and irradiate the optical disk OD. In addition, the lens array 13 makes the reflected light from the optical disk OD enter the plurality of photodetectors 14a to 14d.
[0024]
The plurality of photodetectors 14a to 14d are for detecting the laser beam reflected by the optical disc OD, convert the optical signal received from the optical disc OD through the lens array 13 into an electrical signal, and perform RF (Radio Frequency). ) Play the signal.
Here, the photo detectors 14a and 14d provided close to the connection positions of the support portions 12a and 12b, that is, the movable regions of the movable portions 11a and 11b, are quadrant photodetectors each having four light receiving surfaces, and focus. An error signal can be generated. That is, the photodetector 14a has four light receiving surfaces 30a to 30d. The photodetector 14d has four light receiving surfaces 30e to 30h.
Further, the electrical signal generated by photoelectric conversion by the photodetector 14a detecting the reflected light from the optical disc OD is sent to the tracking error signal generation circuit 16 to enable generation of the tracking error signal TE by the push-pull method.
[0025]
FIG. 4 is a diagram illustrating a circuit formed in the circuit layer 20.
As illustrated, the circuit layer 20 includes servo circuits 15a and 15b, a tracking error signal generation circuit 16, and signal amplification circuits 17a and 17b.
[0026]
The servo circuit 15a is for generating a focus error signal FE1 and a reproduction RF signal RF1 from the signal received from the photodetector 14a, and includes adders 40a and 40b, operational amplifiers 41a and 41b, a phase compensation amplifier 42a, And a driver 43a.
[0027]
The adder 40a adds the signals received from the light receiving surface 30b and the light receiving surface 30c of the photodetector 14a, and sends them to the inverting input terminal of the operational amplifier 41a and the non-inverting input terminal of the operational amplifier 41b.
The adder 40b adds the signals received from the light receiving surface 30a and the light receiving surface 30d of the photodetector 14a, and sends them to the non-inverting input terminals of the operational amplifier 41a and the operational amplifier 41b.
The phase compensation amplifier 42a compensates the phase of the signal received from the output terminal of the operational amplifier 41a and sends it to the driver 43a.
The driver 43a generates a focus error signal FE1 based on the signal received from the phase compensation amplifier 42a and applies it to the movable part 11a through the semiconductor substrate 21.
Thus, the servo circuit 15a is a circuit that generates the focus error signal FE1 by the astigmatism method.
Further, the operational amplifier 41b adds and amplifies the signals received from the adder 40a and the adder 40b, and outputs it as a reproduction RF signal RF1.
[0028]
The servo circuit 15b is for generating a focus error signal FE4 and a reproduction RF signal RF4 from a signal received from the photodetector 14d, and includes adders 40c and 40d, operational amplifiers 41c and 41d, a phase compensation amplifier 42b, And a driver 43b.
[0029]
The adder 40c adds the signals received from the light receiving surface 30e and the light receiving surface 30h of the photodetector 14d, and sends them to the inverting input terminal of the operational amplifier 41c and the non-inverting input terminal of the operational amplifier 41d.
The adder 40d adds the signals received from the light receiving surface 30f and the light receiving surface 30g of the photodetector 14d, and sends them to the non-inverting input terminals of the operational amplifier 41c and the operational amplifier 41d.
The phase compensation amplifier 42b compensates the phase of the signal received from the output terminal of the operational amplifier 41c and sends it to the driver 43b.
The driver 43b generates a focus error signal FE4 based on the signal received from the phase compensation amplifier 42b and applies it to the movable portion 11b through the semiconductor substrate 21.
Thus, the servo circuit 15b is a circuit that generates the focus error signal FE4 by the astigmatism method.
The operational amplifier 41d adds and amplifies the signals received from the adder 40c and the adder 40d, and outputs the amplified signal as a reproduction RF signal RF4.
[0030]
The tracking error signal generation circuit 16 is for generating a tracking error signal from the detection signal of the photodetector 14a, and includes adders 40e and 40f and an operational amplifier 41e.
The adder 40e adds the signals received from the light receiving surface 30a and the light receiving surface 30c of the photodetector 14a, and sends them to the inverting input terminal of the operational amplifier 41e.
The adder 40f adds the signals received from the light receiving surface 30b and the light receiving surface 30d of the photodetector 14a, and sends them to the non-inverting input terminal of the operational amplifier 41e.
The operational amplifier 41e amplifies a signal corresponding to the difference between the signal received from the adder 40e and the signal received from the adder 40f, and outputs the amplified signal as a tracking error signal TE.
[0031]
The signal amplification circuit 17a amplifies the signal received from the photodetector 14b and outputs it as a reproduction RF signal RF2, and includes an amplifier 44a.
The signal amplifying circuit 17b amplifies the signal received from the photodetector 14c and outputs it as a reproduction RF signal RF3, and includes an amplifier 44b.
[0032]
The tracking error signal TE and the reproduction RF signals RF1 to RF4 output from the circuit formed in the circuit layer 20 are sent to a digital signal processing circuit or the like provided in the optical disc recording / reproduction device through, for example, wiring installed in the arm 110. .
[0033]
The operation of the optical head device 100 according to the embodiment of the present invention will be described below. In the optical head device 100, support portions 12a and 12b integrally formed with the lens array 13 include movable portions 11a and 11b, respectively, and a contact position with the semiconductor substrate 21 is defined according to focus error signals FE1 and FE4. In addition, the position of the focal spot can be controlled by adjusting the distance between the optical head array 10 and the lens array 13.
[0034]
Laser light emitted from each of the light emitting elements 10a to 10d included in the optical head array 10 is collected by the lens array 13 and applied to the recording surface of the optical disc OD.
At this time, the laser beams emitted from the light emitting elements 10a to 10d are irradiated to different tracks on the recording surface of the optical disc OD.
The return light reflected by the optical disk OD passes through the lens array 13 and enters the plurality of photodetectors 14a to 14d.
[0035]
Each of the photodetectors 14a to 14d detects incident return light and converts it into an electrical signal.
The photodetector 14 a sends an electrical signal (a signal group consisting of four electrical signals output from the light receiving surfaces 30 a to 30 d) obtained by photoelectric conversion to the servo circuit 15 a and the tracking error signal generation circuit 16.
The photodetector 14b sends an electrical signal obtained by photoelectric conversion to the signal amplifier circuit 17a.
The photodetector 14c sends an electric signal obtained by photoelectric conversion to the signal amplifier circuit 17b.
The photodetector 14d sends an electric signal (a signal group consisting of four electric signals output from the light receiving surfaces 30e to 30h) obtained by photoelectric conversion to the servo circuit 15b.
[0036]
Here, among the plurality of photo detectors 14a to 14d, the photo detector 14a installed in the vicinity of the support portion 12a has four light receiving surfaces 30a to 30d. The photodetector 14d installed in the vicinity of the support portion 12b has four light receiving surfaces 30e to 30h.
[0037]
The servo circuit 15a generates and outputs a reproduction RF signal RF1 by adding the signals received from the light receiving surfaces 30a to 30d included in the photodetector 14a.
[0038]
Further, the servo circuit 15a generates a focus error signal FE1 by an astigmatism method based on signals received from the light receiving surfaces 30a to 30d provided in the photodetector 14a. The servo circuit 15a applies the generated focus error signal FE1 to the movable part 11a through the semiconductor substrate 21.
[0039]
The movable portion 11a is distorted by applying the focus error signal FE1 generated by the servo circuit 15a, and moves the connecting position between the support portion 12a and the semiconductor substrate 21.
Thereby, the support part 12a changes the spatial position of the lens array 13, and adjusts the distance between the optical head array 10 and the lens array 13 so that the return light incident on the photodetector 14a has the best focus. be able to.
[0040]
On the other hand, the servo circuit 15b generates and outputs the reproduction RF signal RF4 by adding the signals received from the light receiving surfaces 30e to 30h included in the photodetector 14d.
[0041]
Further, the servo circuit 15b generates a focus error signal FE4 by an astigmatism method based on signals received from the light receiving surfaces 30e to 30h included in the photodetector 14d. The servo circuit 15b applies the generated focus error signal FE4 to the movable portion 11b through the semiconductor substrate 21.
[0042]
The movable portion 11b is distorted by applying the focus error signal FE4 generated by the servo circuit 15b, and moves the connecting position between the support portion 12b and the semiconductor substrate 21.
Thereby, the support part 12b changes the spatial position of the lens array 13, and adjusts the distance between the optical head array 10 and the lens array 13 so that the focus of the return light which injects into the photodetector 14d becomes the best. be able to.
[0043]
In this way, the support portions 12a and 12b adjust the distance between the optical head array 10 and the lens array 13, whereby the position of the focal spot can be appropriately controlled, and the focus in the two photodetectors 14a and 14d can be controlled. The lens array 13 can be held at the position where the error is removed.
[0044]
Here, the two photodetectors 14a and 14d are installed close to the support portions 12a and 12b, respectively. That is, the photodetectors 14a and 14d are positioned at the ends of the plurality of photodetectors 14a to 14d arranged in a line in the optical head array 10, and detect return light from the optical disc OD. The plurality of photodetectors 14a to 14d detect return light from the optical disc OD having a smooth surface.
Accordingly, the return light detected by the photodetectors 14b and 14c is adjusted by adjusting the distance between the optical head array 10 and the lens array 13 using the focus error signals FE1 and FE4 respectively generated by the servo circuits 15a and 15b. The position of the focal spot of the laser beam can be controlled so that the focus of the laser beam becomes the best.
[0045]
For example, FIG. 5A shows a case where the optical disk OD is free from surface wobbling and warping and is rotated in a horizontal state at the information reading position by the optical head device 100.
In the optical head array 10 in this example, the light emitting element 10a and the photo detector 14a correspond to the track groove located on the inner peripheral side of the optical disc OD, and the light emitting element 10d and the photo detector 14d correspond to the track groove located on the outer peripheral side of the optical disc. It shall be installed in the corresponding orientation.
[0046]
In this case, the support portions 12a and 12b hold the lens array 13 in a horizontal state, and the optical head array 10 and the lens array so that the return light detected by the photodetectors 14a and 14d has the best focus. Adjust the distance to 13.
[0047]
FIG. 5B shows a case where the optical disk OD is rotated in a state where the outer peripheral side is lower than the inner peripheral side at the information reading position by the optical head device 100 due to surface wobbling or warping. Show. In this case, the support portions 12a and 12b are adjusted so that the distance between the light emitting element 10a and the photodetector 14a and the lens array 13 is longer than the distance between the light emitting element 10d and the photodetector 14d and the lens array 13, The position of the focal spot of the laser beam is controlled so that the focus is the best.
[0048]
FIG. 5C shows a case where the optical disc OD is rotated in a state where the inner peripheral side is lower than the outer peripheral side at the information reading position by the optical head device 100 due to surface wobbling or warping. In this case, the support portions 12a and 12b are adjusted so that the distance between the light emitting element 10a and the photodetector 14a and the lens array 13 is shorter than the distance between the light emitting element 10d and the photodetector 14d and the lens array 13, The focal spot of the laser beam is controlled so that the focus is the best.
[0049]
As described above, the support portions 12a and 12b adjust the distance between the optical head array 10 and the lens array 13 in accordance with the focus error signals FE1 and FE4 generated by the servo circuits 15a and 15b, respectively. Tilt control corresponding to OD surface shake or warpage can be performed.
[0050]
In the above embodiment, the support portions 12a and 12b adjust the distance between the optical head array 10 and the lens array 13 in accordance with the focus error signals FE1 and FE4 generated by the servo circuits 15a and 15b, respectively. Although described, it is not limited to this.
That is, the support units 12a and 12b move the lens array 13 in the radial direction of the optical disc OD in accordance with the tracking error signal TE generated by the tracking error signal generation circuit 16 so as to control the position of the focal spot of the laser light. It may be.
[0051]
In this case, the tracking error signal generation circuit 16 applies the tracking error signal TE generated based on the signal received from the photodetector 14 a to the movable parts 11 a and 11 b through the semiconductor substrate 21. The movable portions 11a and 11b change the connection positions of the support portions 12a and 12b and the semiconductor substrate 21 according to the applied tracking error signal TE, and the support portions 12a and 12b and the lens array 13 are moved with respect to the semiconductor substrate 21. Move in parallel.
Thus, for example, as shown in FIG. 6, when the track groove of the optical disk OD is slightly shifted from the optical axis of the laser beam emitted from the optical head array 10, tracking control is performed without changing the position of the arm 110. When executed, the position of the focal spot of the laser beam can be appropriately controlled.
[0052]
In the above embodiment, the support portions 12a and 12b are described as being configured integrally with the lens array 13. However, the present invention is not limited to this, and as shown in FIG. 13 may be configured integrally with the semiconductor substrate 50 on which 13 is installed.
In this case, the distance between the optical head array 10 and the lens array 13 is fixed, and the distance between the optical head array 10 and the lens array 13 integrated with the semiconductor substrate 50 and the optical disk OD is adjusted. Thereby, the position of the focal spot of the laser beam can be appropriately controlled.
[0053]
For example, FIG. 8A shows a case where the optical disc OD is rotated in a state where the outer peripheral side is lower than the inner peripheral side at the information reading position by the optical head device 100 due to surface wobbling or warping. Show. FIG. 8B shows a case where the optical disk OD is rotated at the information reading position by the optical head device 100 with the inner peripheral side lowered from the outer peripheral side.
[0054]
In such a case, the support parts 12a and 12b adjust the height of the integrated optical head array 10 and the lens array 13 by changing the contact position between the movable parts 11a and 11b and the semiconductor substrate 21, The position of the focal spot of the laser beam is controlled so that the focus is the best.
Here, the tracking error signal generation circuit 16 may apply the generated tracking error signal TE to the movable portions 11 a and 11 b through the semiconductor substrate 21.
Thereby, the support parts 12a, 12b and the like move by the same amount in the radial direction of the optical disk OD in accordance with the tracking error signal TE, and the optical head array 10 is moved in parallel with the semiconductor substrate 21 to execute tracking control. Thus, the focal spot of the laser beam can be appropriately controlled.
[0055]
Further, the support portions 12a and 12b may be configured integrally with the optical head array 10 as shown in FIG.
In the example shown in FIG. 9, the lens array 13 is fixed to the semiconductor substrate 21.
In this case, the support parts 12a and 12b change the spatial positions of the optical head array 10 according to the focus error signals FE1 and FE4 applied to the movable parts 11a and 11b from the servo circuits 15a and 15b through the semiconductor substrate 21, respectively. The distance between the optical head array 10 and the lens array 13 is adjusted.
[0056]
Alternatively, as shown in FIG. 10, the optical head array 10 itself may be movable on the semiconductor substrate 21 in the radial direction of the optical disk OD, and tracking control may be executed.
In this case, the tracking error signal generation circuit 16 applies the generated tracking error signal TE to the optical head array 10 through the semiconductor substrate 21, thereby moving the optical head array 10 in the radial direction of the optical disk OD, and The position of the focal spot can be appropriately controlled.
[0057]
In the above-described embodiment, the optical head array 10 has been described as having four light emitting elements 10a to 10d and four photodetectors 14a to 14d arranged in a line. However, the present invention is not limited to this, and more reading is performed. A mechanism may be provided.
For example, as shown in FIG. 11, the optical head array 10 includes a large number of light emitting elements arranged in columns and rows, and the lens array 13 may also include a large number of objective lenses correspondingly.
[0058]
In this case, four support portions 12 a to 12 d are provided to adjust the distance between the optical head array 10 and the lens array 13. Support parts 12a-12d are provided with movable parts 11a-11d in each end.
FIG. 12 is a top view showing the arrangement of the optical head array 10 shown in FIG. 11, the arrangement of the movable regions of the movable portions 11 a to 11 d, and the circuit formed in the circuit layer 20.
[0059]
Here, the photodetectors 18a to 18d installed in the vicinity of the support portions 12a to 12d are quadrant photodetectors each having four light receiving surfaces.
The photo detectors 18a to 18d detect return light and send electric signals obtained by photoelectric conversion to servo circuits 19a to 19d each having the same configuration as the servo circuit 15a or the servo circuit 15b.
Servo circuits 19 a to 19 d formed in the circuit layer 20 generate focus error signals FE 11 to FE 14 from signals received from the photodetectors 18 a to 18 d, respectively, and apply them to the movable parts 11 a to 11 d through the semiconductor substrate 21.
The movable portions 11a to 11d change the shapes according to the applied focus error signals FE11 to FE14, thereby moving the connecting positions of the support portions 12a to 12d and the semiconductor substrate 21, respectively, and the optical head array 10 and the lens. The distance to the array 13 is adjusted.
Thereby, the focal spot of many laser beams can be controlled appropriately.
[0060]
In addition, the movable portions 11a to 11d can have arbitrary configurations that can move the connecting positions of the support portions 12a to 12d and the semiconductor substrate 21, respectively. For example, the movable portions 11a to 11d can be connected to the semiconductor substrate 21 using an electric force or a magnetic force. The contact position can be changed.
[0061]
【The invention's effect】
As described above, according to the present invention, by adjusting the distance between the optical head array and the lens array or the distance between the integrated optical head array and the lens array and the optical disk, a large number can be obtained. It is possible to appropriately control the position of the focal spot of the laser beam.
[Brief description of the drawings]
FIG. 1 is a diagram showing a state in which an optical head device according to an embodiment of the present invention is provided at the tip of an arm.
FIG. 2 is a perspective view for explaining the configuration of the optical head device according to the embodiment of the invention.
FIG. 3 is a diagram for explaining a positional relationship among an optical head array, a support unit, and a lens array.
FIG. 4 is a diagram illustrating a circuit formed in a circuit layer.
FIG. 5 is a view for explaining the operation of the optical head device according to the embodiment of the present invention;
FIG. 6 is a diagram for explaining an operation of a modified example in which a tracking error signal is applied to a movable part.
FIG. 7 is a view showing a modification in which an optical head array and a lens array are integrally formed.
FIG. 8 is a diagram for explaining an operation of a modified example in which an optical head array and a lens array are integrally formed;
FIG. 9 is a view showing a modified example in which the support portion is configured integrally with the optical head array.
FIG. 10 is a diagram showing a modification in which the optical head array itself is movable on the semiconductor substrate.
FIG. 11 is a perspective view showing a configuration of a modified example in which light emitting elements are arranged in columns and rows.
FIG. 12 is a diagram for explaining the arrangement and circuit of a modified example in which light emitting elements are arranged in columns and rows.
[Explanation of symbols]
10 Optical head array
10a to 10d light emitting device
11a-11d Movable part
12a-12d support part
13 Lens array
14a-14d, 18a-18d Photodetector
15a, 15b, 19a-19d Servo circuit
16 Tracking error signal generation circuit
17a, 17b Signal amplifier circuit
20 circuit layers
21, 50 Semiconductor substrate
22 Protective layer
30a-30h Photosensitive surface
40a-40f Adder
41a to 41e operational amplifier
42a, 42b Phase compensation amplifier
43a, 43b driver
44a, 44b amplifier
OD optical disc
FE1, FE4, FE11 to FE14 Focus error signal
TE tracking error signal
RF1 to RF4 Playback RF signal
100 Optical head device
110 arms

Claims (6)

An optical head array comprising a plurality of light emitting elements for emitting multi-beam laser light corresponding to a plurality of tracks on the optical disc, and a plurality of photodetectors for detecting return light from the optical disc;
A lens array in which a plurality of objective lenses for condensing the laser beams emitted from the plurality of light emitting elements on the optical disc are arranged;
At least two support means for adjustably supporting a distance between the optical head array and the lens array;
A second signal created based on a first signal sent from one of the plurality of photodetectors installed close to the support means is applied to the corresponding support means, and the optical head At least two spot control means for controlling the position of the focal spot of the laser light emitted from the plurality of light emitting elements by adjusting the distance between the array and the lens array;
An optical head device. Each of the support means includes, at one end, a movable portion that can move a connection position with the semiconductor substrate on which the optical head array is installed,
Further, each of the support means changes the position of the lens array by moving the movable portion to move the connection position with the semiconductor substrate in accordance with the second signal applied by the corresponding spot control means. Adjusting the distance between the optical head array and the lens array;
The optical head device according to claim 1. Each of the support means includes, at one end, a movable portion that can move a connection position with the semiconductor substrate to which the lens array is fixed,
Further, each of the support means changes the position of the optical head array by moving the connection position of the movable part with the semiconductor substrate in accordance with the second signal applied by the corresponding spot control means. And adjusting the distance between the optical head array and the lens array,
The optical head device according to claim 1. A tracking error signal generated based on a signal group sent from a quadrant photodetector included in the plurality of photodetectors is applied to each of the support means, and the position of each of the support means is the same amount in the radial direction of the optical disc. Provided with tracking control means for moving,
The optical head device according to claim 1, 2, or 3. An optical head array comprising a plurality of light emitting elements for emitting multi-beam laser light corresponding to a plurality of tracks on the optical disc, and a plurality of photodetectors for detecting return light from the optical disc;
A lens array in which a plurality of objective lenses for condensing laser light emitted from the plurality of light emitting elements on the optical disc are arranged, the distance between the optical head array is fixed and fixed;
At least two support means for adjusting the distance between the optical head array and the lens array, and the optical disc;
The optical head is configured to apply a second signal generated based on a first signal sent from one of the plurality of photodetectors installed close to the support means to the corresponding support means. And at least two control means for controlling the position of the focal spot of the laser light emitted from the plurality of light emitting elements by adjusting the distance between the array and the lens array and the optical disc.
An optical head device. A tracking error signal generated based on a signal group sent from a quadrant photodetector included in the plurality of photodetectors is applied to each of the support means, and the position of each of the support means is the same amount in the radial direction of the optical disc. Provided with tracking control means for moving,
The optical head device according to claim 5.

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