JP2012074107A - Optical disk device and on-vehicle equipment using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device capable of obtaining high operational reliability even when condensation occurs.SOLUTION: An optical disk device comprises: a control unit 14 which performs tracking control and focus control on an optical pickup 11 by signals from a light receiving element 22 of the optical pickup 11; and a data storage buffer 15 which stores data of an optical disk 8 obtained via the light receiving element 22. The magnitude of signals from the light receiving element 22 in track jump by the control unit 14 is determined by a determination unit 30 and the operational gain of tracking control and focus control is controlled through the determination by the determination unit 30.

Description

  The present invention relates to an optical disk device that is used in a wide range of environments (temperature, humidity), for example, as in a vehicle, and an in-vehicle device using the same.

  This type of conventional optical disc apparatus has the following configuration.

  That is, a main body case, a rotation driving unit that is provided in the main body case and rotates the optical disk, and an optical disk that is rotated by the rotation driving unit is irradiated with light from the light emitting unit, and reflected light is received by the light receiving unit. An optical pickup that receives light from the optical pickup, a control unit that performs tracking control and focus control of the optical pickup according to a signal from the light receiving unit of the optical pickup, and data that stores data of the optical disk acquired via the light receiving unit The configuration includes a storage buffer.

  Further, a dew condensation sensor for detecting dew condensation is disposed in the main body case (for example, Patent Document 1 below).

  In other words, when dew condensation occurs in the main body case, the signal obtained from the light receiving unit becomes a small object. Therefore, the control unit increases the control gain of tracking control and focus control, thereby achieving appropriate tracking. Control and focus control were possible.

JP 2004-171655 A

  The problem in the conventional example is that the operation reliability when dew condensation occurs is low.

  That is, in the conventional example, the occurrence of dew condensation in the main body case is detected by the dew condensation sensor. However, dew condensation occurs in any part of the optical system related to the disk reproduction signal such as the surface of the optical disk, the inside of the optical pickup or the optical component. It is uncertain whether it occurs, and sometimes the occurrence of condensation cannot be detected.

  When the optical disk apparatus is started in a state where condensation occurs in this way, the amount of light reflected from the optical disk becomes small due to the influence of condensation. At this time, the amount of reflected light may be almost the same as that of a low-reflection disk such as a CD-RW.

  Then, although the optical disk being driven is an optical disk with a high reflectance, servo control is started in a state where it is erroneously detected as an optical disk with a low reflectance, such as a CD-RW. As a result, the reproduction operation is performed with the operation gain adjusted so as to match the low-reflectance optical disc.

  However, with the passage of time after the start of driving, when the ambient temperature changes and condensation is eliminated, the amount of reflected light returns to the original reflected light amount of the high reflectance optical disk, resulting in a high servo gain. Problems occur in terms of flow and operational reliability.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve operational reliability when condensation occurs.

  In order to achieve this object, the present invention provides a main body case, a rotation driving unit that is provided in the main body case, rotates the optical disc, and the optical disk that is rotated by the rotation driving unit. An optical pickup that irradiates light and receives reflected light by a light receiving element, a control unit that performs tracking control and focus control of the optical pickup by a signal from the light receiving element of the optical pickup, and acquired through the light receiving element And a data storage buffer for storing the data of the optical disc, and the control unit determines the magnitude of the signal from the light receiving element when a track jump is performed by the control unit, and the tracking by the determination by the determination unit Control and focus control operating gains are controlled to achieve the intended purpose. It is intended to formed.

  As described above, according to the present invention, the determination unit determines the magnitude of the signal from the light receiving unit when the control unit performs the track jump operation, and the tracking control and focus control operations are performed based on the determination result by the determination unit. Since the gain is controlled, the operation reliability can be improved.

  That is, in the present invention, a change in the signal from the light receiving unit is periodically detected by determining the magnitude of the signal from the light receiving unit when the control unit performs a track jump operation. Therefore, the operation gain of the tracking control and the focus control can be appropriately controlled according to the occurrence of condensation or the elimination thereof, and as a result, the operation reliability when the condensation occurs can be improved. .

The perspective view which shows a mode that the optical disk apparatus in Embodiment 1 of this invention is installed in the cockpit of a motor vehicle. Configuration diagram of the optical disk device Configuration diagram of optical deck unit of optical disk device Configuration diagram of optical pickup unit of optical disc apparatus (A) A diagram showing a state in which three beams are located at the center with respect to the track of the optical disc apparatus. (B) a diagram showing a state in which the three beams are shifted by a quarter with respect to the track of the optical disc apparatus. FIG. 4D is a diagram showing a state in which three beams are deviated by 1/2 with respect to the track of the optical disk apparatus. FIG. 9E is a diagram showing a state in which three beams are deviated by 3/4 with respect to the track of the optical disk apparatus. A figure showing the state of jumping to the next track The figure for demonstrating the shock-proof operation | movement of the optical disk device The figure for demonstrating the information storage in the data storage buffer at the time of the shock proof operation | movement of the optical disk device Flowchart showing operation of shock proof function of the optical disc apparatus Flow chart showing playback operation of the optical disc apparatus The figure which shows the amplitude change of TE signal at the time of dew condensation elimination in the track jump operation | movement of the optical disk apparatus 7 is a flowchart showing the reproduction operation of the optical disc apparatus in Embodiment 2 of the present invention.

(Embodiment 1)
Hereinafter, the optical disk apparatus according to the first embodiment will be described with reference to the drawings.

  FIG. 1 shows a cockpit of an automobile for explaining the first embodiment, FIG. 2 shows a configuration of an optical disc apparatus, and FIG. 3 shows a configuration of an optical deck portion of the optical disc apparatus.

  In FIG. 1, an optical disk device 2 on the left side of a steering wheel 1 is inside a main body case 4 provided with an operation panel portion 3 on the front surface, and the main body case 4 is fixedly installed on a console portion 5 of an automobile.

  As shown in FIG. 2, the optical disk device 2 is inside a main body case 4 and includes an optical deck unit 6 on which main components such as an optical pickup are mounted, a vibration isolation mechanism 7 for attenuating vibrations from the outside, It comprises a loading mechanism (not shown for the sake of simplicity), and a circuit board 10 on which a control IC 9 for controlling these mechanisms is mounted.

  Next, the optical deck unit 6 will be described with reference to FIG. The optical deck unit 6 includes a rotation driving unit 12 that grips and rotates the optical disc 8, a traverse unit 13 that moves the optical pickup 11 to the inner and outer circumferences, an optical pickup 11 that reads information on the optical disc 8, and a control that controls these. IC9. The control IC 9 includes a spindle motor control unit 17, a traverse motor control unit 19, an optical pickup control unit 14, and a data storage buffer 15.

  The rotation drive unit 12 includes a spindle motor control unit 17 and a spindle motor 18. The spindle motor control unit 17 generates a signal for controlling the number of disk revolutions and applies it to the spindle motor 18.

  The traverse unit 13 includes a traverse motor control unit 19 that controls the feeding of the optical pickup 11 and a traverse motor 20. Then, the traverse motor control unit 19 generates a signal for driving the traverse motor 20 and applies the signal to the traverse motor 20.

  The data storage buffer 15 functions as a buffer for storing pre-read data of information on the optical disc 8 in the memory in order to prevent sound skipping due to vibration or shock.

  Here, the optical pickup unit 16 will be described in detail with reference to FIG. 4 showing an outline of the optical pickup unit 16.

  The optical pickup 11 in the optical pickup unit 16 includes a light emitting element 21 that emits laser light, a light receiving element 22 that receives reflected light from the optical disc 8, an optical element 23 that is arranged to adjust the trajectory of the optical path, It comprises a focus actuator 24 that drives the optical element 23 to be slightly displaced in the focus direction, and a tracking actuator 25 that drives the optical element 23 to be slightly displaced in the tracking direction.

  The optical pickup control unit 14 generates each control signal based on the signal from the light receiving element 22 that receives the reflected light from the optical disk 8.

  First, the focus servo will be described. The optical pickup control unit 14 includes a FE signal detection unit 26 that detects a focus error signal (hereinafter referred to as FE signal) that detects a deviation in the height direction from the optical disc 8, and a focus drive calculation that performs focus control based on the FE signal. Part 27. The focus servo is configured by feeding back the calculation result of the focus drive calculation unit 27 to the focus actuator 24.

Next, the tracking servo will be described. A TE signal detection unit 28 that detects a tracking error signal (hereinafter referred to as a TE signal) for detecting a deviation from the track of the optical disk 8 and a tracking drive calculation unit 29 that performs tracking control based on the TE signal are provided. The tracking servo is configured by feeding back the calculation result of the tracking drive calculation unit 29 to the tracking actuator 25. In the tracking servo, there are a trace mode in which information is always read following the track of the optical disc 8 and a track jump mode in which movement is performed to a neighboring track. The tracking drive calculation unit 29 switches the mode and drives the tracking servo mode. I do.

  Further, the optical pickup control unit 14 detects a change in the amplitude of the TE signal in the track jump mode, and determines whether or not servo readjustment is necessary in the same procedure as at the time of activation. Have Detailed processing procedures will be described later.

  Next, the shock proof function will be described with reference to FIGS.

The shock proof function is a well-known function that temporarily holds pre-read disk information in a buffer in order to prevent sound skipping when vibration or shock is applied to the optical disk apparatus 2.

  First, the track jump operation will be described. For example, it is generally well known that the TE signal when a track jump operation is performed for one track has the signal waveform of FIG. 5A shows a state in which three beams are positioned at the center with respect to the track, FIG. 5B shows a state in which the three beams deviate by ¼ from the track, and FIG. 5C shows a track. FIG. 5 (d) shows a state where the three beams are shifted by 3/4 with respect to the track, and FIG. 5 (e) shows a state where the beam jumps to the adjacent track. .

  This principle will be briefly described using the three-beam method often used in CD. Although the case where the three-beam method is used will be described this time, other methods may be used.

  The laser light emitted from the light emitting element 21 is divided into one main beam and two sub beams by a diffraction grating in the optical element 23, thereby forming spots on the optical disk 8. The three spots are arranged so as to be shifted by about 1/4 track pitch in the radial direction (radial direction of the disc), and the return reflected light from the optical disc 8 is received by three independent light receiving elements 22.

  In the case of three beams, a TE signal is generated from the difference between the outputs of the two sub beams to detect a deviation amount from the track, and tracking servo is performed using this value. That is, the tracking drive computing unit 29 controls the spot so that the spot is always located at the center of the track by driving the tracking actuator so that the difference between the two sub beams becomes zero. A state in which tracking control is operating is called a trace mode.

  Here, as an example of the track jump mode, an operation when performing a one-track jump to the inner peripheral side will be described with reference to FIG.

  When performing a track jump, the tracking servo is once turned off and then moved to one track on the inner circumference side. This operation is performed by the tracking drive calculation unit 29 applying a pulse drive voltage to the tracking actuator.

At this time, one of the sub-beams has a maximum return light amount at a position shifted from the track center to the inner circumference side, and the difference between the two sub-beams has the same return light amount at a position shifted by 1/2, and the difference becomes zero again. At a position deviated by 3/4 from the original track, the sub beam on the opposite side has the maximum return light quantity, and is positioned on the inner track side and tracking is turned on again when the difference becomes zero. The time required for the track jump operation is short, and the series of operations are completed in about 5 ms.

  As shown in FIGS. 6 and 7, the shock proof function periodically generates a tracking jump operation and performs a reproduction operation while accumulating a predetermined amount or more of data in the data storage buffer 15. When there is no shock proof function, the data on the track of the optical disk 8 is always traced and data is continuously read.

  On the other hand, if there is a shock proof function, the pre-read information can be stored in the data storage buffer 15 by increasing the rotation speed and the tracing speed of the optical disk 8. This will be described in detail with reference to the flowchart of FIG.

  First, the optical pickup control unit 14 starts shock proof reproduction (step 81), and the data read from the optical disk 8 is accumulated in the data storage buffer 15 (step 82). When the optical pickup control unit 14 detects that the information has been fully accumulated in the data storage buffer 15 (step 83), the tracking drive calculation unit 29 switches the mode to the track jump operation (step 84). In the track jump operation, the information to be read is temporarily returned to the previous information. Therefore, the tracking servo is temporarily turned off, the tracking-on position is returned to the inner circumference side by one or several lines, and tracing is started again. It is.

  That is, the optical pickup control unit 14 performs control so that the information in the buffer always becomes a certain value or more by generating a track jump operation at a frequency of once every few seconds. It should be noted that the number of tracks to be returned by the track jump and the occurrence frequency may be appropriately determined depending on the capacity of the data storage buffer 15. For example, when a memory having a capacity of 16 Mbit is mounted, the generation interval of the track jump operation is generated at a rate of about once every 2 seconds. The shock proof reproduction ends with the end of reproduction of the optical disk 8 (steps 85 and 86).

  In this way, even if there is a case where the servo control is instantaneously lost due to vibration or shock, if the servo control is restored and can be read within the time corresponding to the data information stored in the data storage buffer 15, Playback is possible without interruption of sound. Hereinafter, reproduction using this shock proof function is referred to as shock proof reproduction.

  The operation of the optical disc apparatus 2 when condensation occurs using the shock proof reproduction as described above will be described with reference to the flowchart of FIG.

  When the operator instructs the optical disk apparatus 2 to perform a reproduction operation (step 91), the optical pickup control unit 14 starts a focus servo operation (step 92). Then, the optical pickup control unit 14 specifies the type of the optical disc 8 loaded from the FE signal detected by the FE signal detection unit 26 (step 93). Next, the focus drive calculation unit 27 determines a focus servo gain setting value in accordance with the type of the optical disk 8. Similarly, the tracking drive calculation unit 29 determines a tracking servo gain setting value in accordance with the type of the optical disk 8 (step 94).

  Next, in the case where the type of disc detection in step 93 is not a low-reflectance disc (No in step 95), that is, it is considered that there is no reduction in the amount of return light due to condensation. No change occurs in the amount of return light. Therefore, the normal shock proof regeneration is continuously performed according to the gain setting value performed at the start (step 96).

  On the other hand, if the type of the disc detected in step 93 is a low-reflectance disc (Yes in step 95), the process proceeds to step 97 where the disc type is stored in the data storage buffer 15, and shock proof reproduction is started. The subsequent operations from step 98 to step 100 are the same as those described in the flowchart of FIG.

  When the tracking drive calculation unit 29 switches to the track jump operation mode, in step 101, the TE signal detection unit 28 detects the amplitude Vjmp of the TE signal. Then, the determination unit 30 compares the amplitude Vjmp of the TE signal obtained from the TE signal detection unit 28 with the predetermined value Vd. If the amplitude Vjmp is smaller than the predetermined value Vd (No in step 102), the shock proof reproduction is performed as it is. continue. On the other hand, if the determination unit 30 determines that the amplitude Vjmp is greater than or equal to the predetermined value Vd, the process proceeds to step 103 (Yes in step 102).

  The predetermined value Vd will be described below.

  It is considered that the reason for “Yes” in step 102 is that condensation has occurred in any part of the path through which the light beam passes at the time of activation, and has been eliminated with the passage of time. This is because the gain setting value of the servo system is determined with respect to the amount of return light that has decreased due to condensation at startup, but it is assumed that the servo system has changed to a high gain due to the amount of return light that has recovered as the condensation has been eliminated. When the dew condensation starts, a transient change in the amount of reflected light proceeds at a stretch within about 10 to 30 seconds, and the TE signal causes a gain change of about 12 to 18 dB. FIG. 10 shows a change in the amplitude of the TE signal during the track jump operation in the case where the reproduction is started in the state where the condensation is erroneously detected at the time of start-up and the condensation is eliminated as time elapses.

Because this gain change greatly exceeds the effects of ambient temperature changes and disturbances that are normally assumed, a series of servo readjustments from disc type identification to gain adjustment are performed again with the original light quantity of the disc without condensation. There must be. The predetermined value Vd is preferably a value of Vd = (TE amplitude at the time of tracking jump of a high reflectivity disk) / (TE amplitude at the time of tracking jump of a low reflectivity disk) Servo readjustment lowers the servo gain, so there is no problem with overcurrent.

  Hereinafter, the description returns to the flow description. When the amplitude value Vjmp is greater than or equal to the predetermined value Vd, it is considered that condensation has occurred in any part of the path through which the light beam passes during startup as described above, and has been eliminated with time.

  In Step 103 to Step 106 in FIG. 9, servo readjustment is performed in the same procedure as that at the time of activation. That is, the optical pickup control unit 14 turns on the focus servo (step 104) and performs disk detection (step 105). Then, the focus drive calculation unit 27 and the tracking drive calculation unit 29 determine the gain setting values for the focus servo and tracking servo (step 106). Thereafter, shock proof reproduction is resumed (step 107). Then, the disc reproduction is ended by an operator's instruction to turn off the operation or the like.

In this way, every time a track jump operation for shock proof reproduction occurs, the TE signal is periodically checked for the presence or absence of dew condensation, and if there is a significant change, servo readjustment is performed. Therefore, even when the ambient temperature changes with the passage of time and condensation is eliminated, servo readjustment is automatically performed, and the gain of each servo is reset to an optimum value in the state of the original reflected light quantity of the disk. . Therefore, high operational reliability of the optical disc apparatus 2 can be ensured.

  Further, the occurrence interval of the track jump operation by the shock proof reproduction is about 2 seconds as described above. Therefore, since the time from the start of dew condensation to the return to the original light amount of the disk is 10 to 30 seconds, the time interval is sufficient to detect dew condensation with high accuracy.

  In addition, since the determination process is performed when the disk detection result immediately after startup is a low-reflectance disk, in order to reliably capture the case where the change in the amount of light due to dew condensation is maximized and perform servo readjustment Operation reliability can be improved.

In Embodiment 1 of the present embodiment, the signal from the light receiving element 22 determined by the determination unit 30 is described as a TE signal, but other signals that cause a similar change due to the return of the light amount when dew condensation is eliminated are used. May be. That is, an E signal or F signal for generating a TE signal, or an FE signal or an RF signal may be used as a signal from the light receiving element 22 used for determination. Similarly, although the magnitude of the signal from the light receiving element determined by the determination unit 30 is described as the amplitude of the TE signal, the DC offset values of the TE signal, the FE signal, and the RF signal may be used for the determination. .
(Embodiment 2)
The optical disk apparatus according to Embodiment 2 of the present invention will be described below with reference to the drawings.

  The second embodiment is different in that the amplitude value of the TE signal is stored as an initial value in a memory included in the determination unit 30 at the time of the first track jump, and the determination unit 30 determines based on the amount of change from the initial value.

  This will be described in detail with reference to the flowchart of FIG.

  Since Step 91 to Step 100 and Step 103 to Step 107 are the same processing contents as those in the first embodiment, description and illustration are omitted.

  When the tracking drive calculation unit 29 switches to the track jump operation mode, in step 108, the TE signal detection unit 28 detects the amplitude Vjmp of the TE signal. If the optical pickup control unit 14 determines that the track jump is first generated after activation (Yes in Step 109), the initial value Vjmp0 of the amplitude of the TE signal is stored in the memory included in the determination unit 30 (Step 110). ). When the track jump is the second time or later (No in Step 109), the determination unit 30 calculates the amount of change ΔVjmp from the initial value Vjmp0 of the amplitude Vjmp (Step 111).

  Next, in step 112, the amount of change ΔVjmp is compared with a predetermined value ΔVd. If ΔVjmp is smaller than the predetermined value ΔVd, the process returns to step 98 to continue the shock proof reproduction as it is. If ΔVjmp is equal to or greater than the predetermined value ΔVd, as in the first embodiment, after all the servos are turned off, servo readjustment is performed in the same procedure as at the time of startup.

  As described above, it is determined whether the servo readjustment due to the occurrence of dew condensation is necessary based on the amount of change from the initial value of the TE signal amplitude. Even when there is a variation, it is possible to accurately determine the necessity of servo readjustment.

The optical disk apparatus of the present invention can ensure high operation reliability by always setting an optimum gain even when condensation occurs in the apparatus due to a change in use environment. Useful as.

DESCRIPTION OF SYMBOLS 1 Steering 2 Optical disk apparatus 3 Operation panel part 4 Main body case 5 Console part 6 Optical deck part 7 Anti-vibration mechanism 8 Optical disk 9 Control IC
DESCRIPTION OF SYMBOLS 10 Circuit board 11 Optical pick-up 12 Rotation drive part 13 Traverse part 14 Optical pick-up control part 15 Data storage buffer 16 Optical pick-up part 17 Spindle motor control part 18 Spindle motor 19 Traverse motor control part 20 Traverse motor 21 Light emitting element 22 Light receiving element 23 Optical Element 24 Focus actuator 25 Tracking actuator 26 FE signal detection unit 27 Focus drive calculation unit 28 TE signal detection unit 29 Tracking drive calculation unit 30 Determination unit

Claims (9)

  A main body case, a rotation driving unit that is provided in the main body case, rotates the optical disk, and irradiates light from the light emitting element to the optical disk rotated by the rotation driving unit, and receives the reflected light by the light receiving element. An optical pickup, a control unit that performs tracking control and focus control of the optical pickup according to a signal from the light receiving element of the optical pickup, and a data storage buffer that stores the data of the optical disk acquired through the light receiving element A determination unit that determines the magnitude of a signal from the light receiving element when the control unit causes a track jump, and the operation gain of the tracking control and the focus control is controlled by the determination by the determination unit; Optical disk device.   The optical disk apparatus according to claim 1, wherein a signal obtained from the light emitting element when a track jump is performed by the control unit is a tracking error signal of the optical disk.   The optical disc apparatus according to claim 1, wherein the determination by the determination unit is performed every time the control unit generates the track jump.   2. The optical disc according to claim 1, wherein the determination by the determination unit is performed when the control unit specifies that an initial level of a signal magnitude from the light receiving element is a level of a low reflection disc. apparatus.   A main body case, a rotation driving unit that is provided in the main body case, rotates the optical disk, and irradiates light from the light emitting element to the optical disk rotated by the rotation driving unit, and receives the reflected light by the light receiving element. An optical pickup, a control unit that performs tracking control and focus control of the optical pickup according to a signal from the light receiving element of the optical pickup, and a data storage buffer that stores the data of the optical disk acquired through the light receiving element The amount of change from immediately after the start of the magnitude of the signal from the light receiving element when the control unit causes a track jump to be calculated is calculated by the calculation unit, and the tracking control and focus control are performed according to the calculation result of the calculation unit An optical disc apparatus configured to control the operation gain of the optical disc.   6. The optical disc apparatus according to claim 5, wherein a signal obtained from the light emitting element when the control unit causes a track jump is a tracking error signal of the optical disc.   6. The optical disc apparatus according to claim 5, wherein the determination by the determination unit is performed every time the control unit generates the track jump.   7. The optical disc according to claim 6, wherein the determination by the determination unit is performed when the control unit specifies that an initial level of a signal magnitude from the light receiving element is a level of a low reflection disc. apparatus.   An in-vehicle device on which the optical disk device according to claim 1 is mounted.