JP3817198B2 - Optical path control device, optical path control method, and optical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical path control device, an optical path control method, and an optical device in an apparatus.
[0002]
[Prior art]
Conventionally, in an optical system in an optical disk apparatus, as shown in FIG. 8, when reading a medium, light emitted from a laser 71 is transmitted through a collimator lens 72 and the plane of polarization is aligned, and is set up by a beam splitter (1) 73. It goes to the medium 76 by the upper mirror 74. The objective lens 75 works to focus the light directed toward the medium 76 with the medium 76. The light whose polarization plane has been changed by the Kerr effect due to the magnetic field of the medium 76 passes through the objective lens 75, the rising mirror 74, and the beam splitter (1) 73 toward the beam splitter (2) 77. The beam splitter (2) 77 is divided into an optical system for a servo system for performing track and focus control and an optical system for reading a signal written on the medium 76.
[0003]
In the optical system that reads a signal written on the medium 76, the polarization plane of the light is +45 degrees by the wave plate 78, and the light is split by the polarization beam splitter 79. The MO detector 80 converts the two lights into electrical signals. The electric signal is subjected to addition amplification and differential amplification by the head amplifier 23 to read the ID signal and the MO signal. The MO signal is modulated to obtain read data.
[0004]
The optical system optical path of the servo system for performing the track and focus control divided by the beam splitter (2) 77 is divided by the TES (TRACK ERROR SIGNAL) by the beam splitter (3) 82, and the TES detector 83 divided by two. The signal is converted into a signal and amplified by the head amplifier 23.
[0005]
FES (FOCUS ERROR SIGNAL) is converted into an electrical signal by the FES detector 86 via the S lens 84, the beam splitter (3) 82, and the S prism 85, and is amplified by the head amplifier 23.
[0006]
[Problems to be solved by the invention]
In recent years, with the development of laser diodes, a red laser to a blue laser have been used so far, and the beam diameter has been reduced, and accordingly, large-capacity recording has become possible. Because the light frequency is increased (E∝f2) and the beam diameter is reduced, the light energy density is also increased and the optical path through which the light passes is always constant. Therefore, the excess energy of the beam splitter and detector Degradation begins gradually with damage to the crystal lattice or sensor particles. Even if only a small number of crystal lattices or sensor particles are destroyed, there is not much problem with the function of the device. However, if the number of defects increases or discolors into partial large defects, the MO, TES, and FES signals Since the signal level is reduced and the noise is increased, the S / N is significantly reduced, and the function as the device is not satisfied.
[0007]
For this reason, the above-described deterioration shortens the life of the optical disc apparatus. Here, the part that does not function due to an increase in defects, or the part that does not function partially due to discoloration, etc. will be referred to as “burn”.
[0008]
Therefore, since the optical path is always constant, the destruction of the crystal lattice and the destruction of the sensor particles proceed gradually only in the portion where the light from the beam splitter or detector is irradiated. In addition, since the crystal lattice and sensor particles are normal in the part that was not exposed to light, if the part that is currently exposed to light is burnt, it will be normal even if the part that is exposed to light is slightly burned. It is desired to operate.
[0009]
In order to solve these problems, the present invention moves the irradiation position of the beam to the element in the optical path of the optical disk apparatus to automatically avoid the burning due to the beam irradiation on the element, thereby improving the life. The object is to avoid the trouble of replacing elements.
[0010]
[Means for Solving the Problems]
Means for solving the problem will be described with reference to FIG.
[0011]
In FIG. 1, a medium 76 reads and writes data by irradiating a laser beam.
[0012]
The carriage 102 is for irradiating a focused laser beam on a corresponding position of the medium 76 or taking in a reflected laser beam.
[0013]
The fixed optical system 103 generates a laser beam and irradiates the medium 26 with the laser beam via the carriage 102, converts the reflected laser beam back to an electrical signal, a focus, a track servo, etc. For example, a signal for performing various controls is detected.
[0014]
The moving mechanism 101 is a mechanism for moving the position irradiated with the laser light for the elements used in the fixed optical system 103 (34 to 40 in the figure).
[0015]
Next, the operation will be described.
The laser beam emitted from the laser 71 constituting the fixed optical system 103 is irradiated onto the medium 76 via the carriage 102, and the reflected laser beam is detected by the detector constituting the fixed optical system 103, and the laser An element group arranged on the path until the laser light emitted from the irradiation source reaches the medium, and an element group arranged on the path until the laser beam reflected from the medium is detected by the detection element One or a plurality of elements are provided with a moving mechanism 101 that moves the position irradiated with the laser light, and the moving mechanism 101 is moved when the intensity of the signal detected by the detecting element or the S / N ratio decreases. It is adjusted and moved to a larger position.
[0016]
At this time, when the signal strength or S / N ratio is smaller than a predetermined value when the medium 76 is loaded, the element is moved to a position where the element is increased by the moving mechanism 101.
[0017]
Accordingly, it is possible to automatically avoid the burning due to the beam irradiation to the element by moving the irradiation position of the beam in the optical path of the optical disk apparatus, to improve the life and to avoid the trouble of replacing the element. It becomes possible.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments and operations of the present invention will be described sequentially in detail with reference to FIGS. Here, 71 to 80, 82 to 86, and 23 in FIG. 1 are the same as those in FIG.
[0019]
FIG. 1 shows a system configuration diagram of the present invention.
In FIG. 1, a moving mechanism 101 is a mechanism for moving the position of an element that is exposed to laser light. In FIG. 1, a beam splitter (1) elevator 34, a beam splitter (2) elevator 35, a wavelength plate elevator 36, a deflected beam. It comprises a splitter elevator 37, an MO detector elevator 38, a beam splitter (3) elevator 39, a TES detector elevator 40, and the like. These will be described below in order, divided into detectors and beam splitters.
[0020]
FIG. 2 shows an example of burnout according to the present invention.
FIG. 2A shows an example of detector burnout. When the detector is irradiated with laser light as shown on the left and it is detected that the S / N of the damaged portion shown in the figure is lower than a predetermined threshold value, the detector is moved as indicated by the dotted circle (the moving mechanism 101 is shown in FIG. 3), as shown on the right side, the S / N ratio can be almost restored to the original value.
[0021]
FIG. 2B shows an example of beam splitter burning. Similarly to the detector, as shown on the left side, when the beam splitter is irradiated with the laser beam and the S / N of the damaged portion shown in the figure is detected to be lower than the predetermined threshold, it moves as indicated by a dotted circle. (For the moving mechanism 101, see FIG. 3), it is possible to almost restore the S / N ratio to the original value for both transmitted light and reflected light shown on the right side.
[0022]
FIG. 3 shows an example of the moving mechanism of the present invention.
FIG. 3A shows a specific example of a moving mechanism in the case of raising and lowering.
[0023]
(A-1) of FIG. 3 shows the example of a raising / lowering mechanism (manual). The upper part shows a side sectional view, and the lower part shows a bottom view. Here, when an element to be moved up and down (for example, the MO detector 38 in FIG. 1) is mounted on the table 111 and the operator rotates the screw 113 provided in the enclosure 112 with a screwdriver or the like, along with the rotation of the screw 113. The elements on the table 111 are moved up and down. At this time, the rotation of the table 111 is prevented by the rotation preventing rod 114 and the table 111 is pushed upward by the spring 115 so as not to be affected by play (gap) of the screw 113.
[0024]
(A-2) in FIG. 3 shows an example of an elevating mechanism (automatic). The upper part shows a side sectional view, and the lower part shows a bottom view. Here, by energizing the electromagnet 116 to generate a force (predetermined attractive force or predetermined repulsive force), the table 11 is raised and lowered as in (a-1) of FIG. When the S / N ratio falls below a predetermined threshold, it is possible to automatically restore based on the S / N ratio.
[0025]
FIG. 3B shows a specific example of a moving mechanism (manual) in the case of left-right movement.
FIG. 3B-1 shows an example of a mobile device (manual). The left side shows a left side view, and the right side shows a front sectional view. Here, when an element to be moved left and right is mounted on the table 111 and the operator rotates the screw 113 provided in the enclosure 112 with a screwdriver or the like, the element on the table 111 moves to the left and right as the screw 113 rotates. To do.
[0026]
(B-2) of FIG. 3 shows a specific example of the moving mechanism (automatic) in the case of left-right movement. The left side shows a left side view, and the right side shows a front sectional view. Here, by energizing the electromagnet 120 provided between the magnets 118 to generate a force (predetermined attractive force or predetermined repulsive force), the table 11 is moved in the horizontal direction in the same manner as in FIG. When the medium 76 is loaded, the S / N ratio can be automatically restored based on the S / N ratio when the S / N ratio falls below a predetermined threshold.
[0027]
It should be noted that the portion of the optical element itself that is exposed to light is a pinpoint, and an element that loses its function by movement or an element that changes its optical path due to movement and cannot be moved cannot be moved. Not applicable. Here, when each element of the fixed optical system is classified according to FIG. 1, the elements that cannot be moved are the laser 71, the collimating lens 72, the S lens 84, the S prism 85, and the FES detector 86, which are movable only in the vertical direction. Are an MO detector 81 and a TES detector 83. Elements that can be moved up and down and left and right with respect to the optical path are a beam splitter (1) 73, a beam splitter (2) 77, a polarization beam splitter 79, and a beam splitter (3) 83. is there.
[0028]
4 and 5 show a control flowchart of the present invention. Hereinafter, the operation in the case of control will be described with reference to the circuit block diagram of FIG.
[0029]
In FIG. 4, in S <b> 1, the MPU acquires a set value of the position current of each elevator 34 to 40 from the memory.
[0030]
In S2, the MPU passes the currents to the respective drivers 16 to 22 through the DSP according to the position current set values to determine the positions of 33 to 40.
[0031]
In S3, manufacturing information written on the optical disk (medium 76) is read.
S4 determines whether the TES signal is abnormal. In the case of YES, it is found that the TES signal is abnormal and that the laser beam has been irradiated onto the element by the moving mechanism according to the present invention, so the process proceeds to S11 in FIG. In the case of NO, since it is found to be normal, the process proceeds to S5.
[0032]
S5 determines whether the FES signal is abnormal. If YES, it is determined that the FES signal is abnormal and that the laser beam has been irradiated onto the element by the moving mechanism according to the present invention, so that the process proceeds to S31. In the case of NO, since it is found to be normal, the process proceeds to S6.
[0033]
In S6, it is determined whether the ID signal is abnormal. In the case of YES, since the ID signal is abnormal and it has been found that the laser beam is irradiated on the element by the moving mechanism according to the present invention, the process proceeds to S21 in FIG. In the case of NO, since it is found to be normal, the process is terminated.
[0034]
(1) If it is determined that the TES signal is abnormal (deterioration of signal) in S4 YES:
In FIG. 5, in S11, the DSP controls the driver 22 to raise and lower the TES detector 40 to search for a current that improves the signal.
[0035]
In step S12, it is determined whether there is a current to be improved. If YES, the DSP controls the driver 22 in S13 to return the TES detector to its original position. Then, the process proceeds to S31 in FIG. On the other hand, in the case of NO in S12, the process proceeds to S41 in FIG.
[0036]
(2) If YES in S5 indicates that the FES signal is abnormal (deterioration of signal):
In FIG. 4, in S31, the DSP controls the driver 21 and moves up and down the beam splitter (3) 39 to search for a current that improves the signal.
[0037]
In step S32, it is determined whether there is a current to be improved. If YES, the process proceeds to S33. In the case of NO, since it has been found that there is a current to be improved, the process proceeds to S41.
[0038]
In S33, the DSP controls the driver 21 to return the beam splitter (3) 39 to the original position.
[0039]
In S34, the DSP controls the driver 17 and moves up and down the beam splitter (2) 35 to search for a current that improves the signal.
[0040]
In S35, it is determined whether there is a current to be improved. If YES, the process proceeds to S36. In the case of NO, since it has been found that there is a current to be improved, the process proceeds to S41.
[0041]
In S36, the DSP controls the driver 17 to return the beam splitter (2) 35 to the original position.
[0042]
In S37, the DSP controls the driver 16 to move up and down the beam splitter (1) to search for a current that improves the signal.
[0043]
In S38, it is determined whether or not there is a current to be improved. If YES, the process proceeds to S39. In the case of NO, since it has been found that there is a current to be improved, the process proceeds to S41.
[0044]
In S39, the DSP controls the driver 16 to return the beam splitter (1) 34 to the original position.
[0045]
In S40, the DSP displays an alarm (message indicating that the S / N cannot be improved even if the element is moved) on the MPU. And it ends.
[0046]
(3) If it is determined that the ID signal is abnormal (deterioration of signal) in S6 YES:
In FIG. 5, in S21, the DSP controls the driver 20 to raise and lower the MO detector 38 to search for a current that improves the signal.
[0047]
In step S22, it is determined whether there is a current to be improved. If YES, the process proceeds to S23. In the case of NO, since it has been found that there is a current to be improved, the process proceeds to S41 in FIG.
[0048]
In S23, the DSP controls the driver 20 to return the MO detector 38 to the original position.
[0049]
In S24, the DSP controls the driver 19 to move up and down the deflection beam splitter 37 to search for a current that improves the signal.
[0050]
In S25, it is determined whether there is a current to be improved. If YES, the process proceeds to S26. In the case of NO, since it has been found that there is a current to be improved, the process proceeds to S41 in FIG.
[0051]
In S26, the DSP controls the driver 19 to return the deflecting beam splitter 37 to the original position.
[0052]
In S27, the DSP controls the driver 18 and moves up and down the wave plate 36 to search for a current that improves the signal.
[0053]
In S28, it is determined whether or not there is a current to be improved. If YES, the process proceeds to S29. In the case of NO, since it has been found that there is a current to be improved, the process proceeds to S41 in FIG.
[0054]
In S29, the DSP controls the driver 18 to return the wave plate 36 to the original position. Then, the process proceeds to S34 in FIG.
[0055]
In FIG. 4, S41 notifies the location where the DSP has improved to the MPU and the current value.
[0056]
In S42, the MPU rewrites the improved current value in the memory.
In S43, the MPU leaves the current value before improvement as a burnout history in the memory. And it ends.
[0057]
As described above, when an abnormality (signal deterioration) in the TES signal, the FES signal, and the ID signal is detected based on the signal read from the medium 76, the moving mechanism 101 (34 to 40) in FIG. , Sequentially control (up and down movement, left and right movement), when the signal is improved, it is updated to the improved current value, the updated current value is stored in the memory, and the history of the place where the previous current value was damaged If the S / N ratio of the TES signal, FES signal, ID signal, etc. falls below a predetermined threshold and is found to be abnormal, the location where the laser beam is irradiated is automatically moved. It is possible to automatically improve the S / N ratio.
[0058]
FIG. 6 shows a circuit block diagram of the present invention. This is a circuit block diagram used for the configuration of FIG. 1 described above, and according to the flowcharts of FIG. 4 and FIG. It is a circuit block diagram when improving a ratio automatically.
[0059]
In FIG. 6, an MPU 1 is a microprocessor and performs overall control according to a program.
[0060]
The memory 2 stores data. Here, the memory 2 stores a current value at which a good S / N ratio is obtained with respect to the moving mechanism 101 (the moving mechanism 34 to 40 in FIG. 1). is there.
[0061]
The interface 3 is an interface for exchanging data with the host device.
[0062]
The crystal unit 4 generates a clock.
The ODC optical disk controller 5 performs control such as formatting an optical disk and performing ECC processing.
[0063]
The read / write LSI circuit 6 writes or reads data on an optical disk (medium 76).
[0064]
The DSP 7 performs various controls at high speed. Here, the DSP 7 drives a driver or the like, and performs various controls by taking in signals from the TES detection circuit 9 and the FES detection circuit 10. .
[0065]
Drivers 11 to 22 drive motors, actuators, elevators and the like.
[0066]
The moving mechanism 101 moves a splitter or the like up and down or left and right.
[0067]
FIG. 7 shows an example of the MO waveform of the present invention.
7A shows a waveform at the time of burning, and FIG. 7B shows a waveform before burning avoidance or before burning. Here, when the element is irradiated with laser light and burned out, the harmonic component of the MO signal waveform is reduced and the amplitude is reduced as shown in the figure. Here, the harmonic component is noise, and the S / N ratio is lowered as a result of the increase in N and the decrease in S. When the S / N ratio falls below a predetermined value, as described above, the laser beam irradiation place is moved up and down or left and right by the moving mechanism 101 as shown in FIG. It is possible to set the current value (location) where the S / N ratio has been recovered to automatically restore the deterioration of the S / N ratio.
[0068]
(Appendix 1)
In the optical path control device in the device,
Element group arranged on the path until the laser beam emitted from the laser irradiation source reaches the medium, and element group arranged on the path until the laser beam reflected from the medium is detected by the detection element An optical path control device comprising a moving mechanism for moving one or a plurality of elements to a position irradiated with the laser light.
[0069]
(Appendix 2)
The optical path control device according to claim 1, further comprising means for adjusting the moving mechanism to move it to a position where it increases when the intensity or S / N ratio of the signal detected by the detecting element decreases. .
[0070]
(Appendix 3)
3. The optical path control according to appendix 1 or appendix 2, wherein when the medium is loaded, the element is moved to a position where the signal is increased by the moving mechanism when the signal intensity or S / N ratio is smaller than a predetermined value. apparatus.
[0071]
(Appendix 4)
In the optical path control method in the apparatus,
Element group arranged on the path until the laser beam emitted from the laser irradiation source reaches the medium, and element group arranged on the path until the laser beam reflected from the medium is detected by the detection element The position where the laser beam is irradiated to one or a plurality of elements is moved by a moving mechanism provided in the element, and the intensity or S / N ratio of the signal detected by the detection element is increased. An optical path control method characterized by the above.
[0072]
(Appendix 5)
When the intensity or S / N ratio of the signal detected by the detection element becomes smaller than a predetermined value, the element is moved by the moving mechanism to increase the intensity or S / N ratio of the signal. The optical path control method according to appendix 4.
[0073]
(Appendix 6)
In the optical device,
Element group arranged on the path until the laser beam emitted from the laser irradiation source reaches the medium, and element group arranged on the path until the laser beam reflected from the medium is detected by the detection element An optical device comprising a moving mechanism for moving one or a plurality of elements to a position irradiated with the laser light.
[0074]
【The invention's effect】
As described above, according to the present invention, the irradiation position of the beam to the element in the optical path of the optical disk apparatus is moved to automatically avoid the burning due to the beam irradiation on the element, thereby improving the life. It is possible to avoid the trouble of exchanging elements. This
(1) If the optical element can be moved manually and the optical element is burnt, it can be repaired by simply moving it to a non-burned part, and the number of replacement parts can be reduced.
[0075]
(2) When the optical element is loaded on the medium, the optical element at the spot that seems to be burned is moved and moved to the non-burned area, and the burn of the optical element is automatically avoided, and the optical disk device stops functioning due to the burning of the optical element. Can be prevented.
(3) The burned element and burned current value are recorded as the history, and the status of the optical element can be easily grasped.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an optical system of an optical disc apparatus according to the present invention.
FIG. 2 is an example of burnout according to the present invention.
FIG. 3 is an example of a moving mechanism of the present invention.
FIG. 4 is a control flowchart (No. 1) according to the present invention.
FIG. 5 is a control flowchart (No. 2) according to the present invention.
FIG. 6 is a circuit block diagram of the present invention.
FIG. 7 is an example of an MO waveform according to the present invention.
FIG. 8 is a schematic diagram of an optical system of a conventional optical disc apparatus.
[Explanation of symbols]
1: MPU
2: Memory 11-22: Driver 34: Beam splitter (1) Elevator 35: Beam splitter (2) Elevator 36: Wave plate elevator 37: Deflection beam splitter elevator 38: MO detector elevator 39: Beam splitter (3) Elevator 40: TES detector lift 71: laser 72: collimator lens 73: beam splitter (1)
74: Upright mirror 75: Objective lens 76: Medium 77: Beam splitter (2)
78: Wave plate 79: Deflection beam splitter 80: MO detector 83: TES detector 86: FES detector 101: Moving mechanism 102: Carriage 103: Fixed optical system

Claims (5)

In the optical path control device in the device,
Element group arranged on the path until the laser beam emitted from the laser irradiation source reaches the medium, and element group arranged on the path until the laser beam reflected from the medium is detected by the detection element An optical path control device comprising a moving mechanism for moving one or a plurality of elements to a position irradiated with the laser light. 2. The optical path control according to claim 1, further comprising means for adjusting the moving mechanism to move it to a larger position when the intensity or S / N ratio of the signal detected by the detecting element decreases. apparatus. In the optical path control method in the apparatus,
Element group arranged on the path until the laser beam emitted from the laser irradiation source reaches the medium, and element group arranged on the path until the laser beam reflected from the medium is detected by the detection element The position where the laser beam is irradiated to one or a plurality of elements is moved by a moving mechanism provided in the element, and the intensity or S / N ratio of the signal detected by the detection element is increased. An optical path control method characterized by the above. When the intensity or S / N ratio of a signal detected by the detection element becomes smaller than a predetermined value, the element is moved by the moving mechanism to increase the intensity or S / N ratio of the signal. The optical path control method according to claim 4. In the optical device,
Element group arranged on the path until the laser beam emitted from the laser irradiation source reaches the medium, and element group arranged on the path until the laser beam reflected from the medium is detected by the detection element An optical device comprising a moving mechanism for moving one or a plurality of elements to a position irradiated with the laser light.

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