JPH0254428A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform track jump in a wide range by one time of jump by interlocking and moving also a pickup travel mechanism with a tracking actuator. CONSTITUTION:When the address of a targeted track is supplied, a switch SW1 is switched to a contact (b) by a controller 31, and a tracking error signal from the controller 31 via a counter 36, a frequency voltage converter 37, a differential amplifier 38, a jump direction switching circuit 32, and a phase compensation circuit 33, etc., is supplied, which controls the tracking actuator 19. Similarly, the tracking error signal via a voice coil motor 6 which controls the acceleration of the pickup travel mechanism being interlocked with the actuator 19 reacting according to the tracking error signal and a current detector 24 is also supplied to the actuator 19 via an adder 17. It is possible to perform multitrack jump in a wide range by one time of jump by interlocking the tracking actuator with the pickup travel mechanism.

Description

[Detailed Description of the Invention] [Prior Art] In recent years, information has been optically transmitted by condensing a light beam and irradiating it onto an optical recording medium (hereinafter referred to as an optical disk) to form a bit string etc. on the optical disk. 2. Description of the Related Art There is an optical recording/reproducing device (hereinafter referred to as an optical disk device) that is capable of recording information on a disk and reproducing recorded information by receiving return light from a recorded bit string or the like.

Since the above-mentioned optical disk device can record information at high density, the number of tracks on which information is recorded is also very large.

Therefore, it is necessary to be able to access the target track in a short time.

In a generally widely performed one-track jump, the jump time is around 1 [11SeC], and even if there is optical disk eccentricity, the optical beam position on the optical disk from the start of the jump to the end of the jump will change to that extent. Since the relative speed between the track moving speed and the beam moving speed due to optical disk eccentricity does not change much, a stable single track jump can be performed using acceleration pulses and deceleration pulses.

By the way, it takes time to jump one track at a time and move to a target track that is several tracks away.

For this reason, Japanese Patent Publication No. 63-25411, Japanese Patent Publication No. 61-2
The first and second conventional examples of No. 67938 disclose an access means using a multi-track jump that continuously moves a plurality of tracks with one jump.

[Problem to be Solved by the Invention 1] The first conventional example described above only moves the light beam during a jump, but does not move the pickup transport mechanism such as a VCM that moves the optical pickup.

For this reason, the number of moving tracks for multi-jump is restricted.

In addition, since the disk is generally rotated eccentrically, if the eccentricity is large, it will already be in a position unevenly distributed from its original equilibrium position, and if you make track jumps in the direction of further unevenly distributed from this state, the number of track jumps that can be moved is Since the number of tracks becomes very small, a situation may occur in which the desired number of multi-track jumps cannot be performed.

In other words, in this conventional example, the number of tracks that can be multi-track jumped is limited.

Also, in the second conventional example, the pickup feeding mechanism is temporarily stopped during multi-track jump, and in this state, the actuator is moved at high speed by a predetermined number of tracks within the operating range of the actuator allowed in the pickup state. Yes. Therefore, even in this conventional example, there is a drawback that the number of tracks that can be multi-track jumped at one time is reduced to 11.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide an optical recording/reproducing device that can perform multi-track jumps over a wide range without being restricted by the movable range of an objective lens.

[Means and effects for solving the problem] In the present invention, in an apparatus for projecting a light beam from a light beam generating means to a recording medium via a beam projection means, the light beam is moved in a direction across tracks of the recording medium. a first moving means; a second moving means for moving the first moving means in a direction across the tracks of the recording medium; first and second drive signal generating means for generating first and second drive signals to be applied to the second moving means, the first moving means being driven by the first drive signal; In this case, the first drive signal is applied to the second moving means. This configuration makes it possible to move the second moving means in conjunction with the first moving means, so that a single multi-track jump can cover a wide range of multi-track jumps without being affected by the movable range of the first moving means. I'm trying to do it.

[Example] Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIGS. 1 to 7 relate to the first embodiment of the present invention.
Figure 2 is a block diagram of the track access means in the first embodiment, Figure 2 is an overall diagram of the first actual example, Figure 3 is an explanatory diagram of the case of multi-track jumping to the inner circumference, and Figure 4 is an illustration of the track access means in the first embodiment. Figure 5 is a circuit diagram of a comparator with hysteresis characteristics, Figure 6 is a diagram showing the characteristics of an F/V converter, and Figure 7 is an illustration of a multi-track jump on the outer side. FIG. 7 is an explanatory diagram of the operation when the track jump is performed to the inner circumferential side after the jump.

As shown in FIG. 2, the optical recording/reproducing apparatus of the first embodiment (
An optical disk device) 1 has an optical pickup 4 facing an optical disk 3 which is rotationally driven by a spindle motor 2.
has been set up. This optical pickup 4 is attached to a carriage 5 and is driven by a voice coil motor (abbreviated as VCM).
It is made movable in the radial direction of the optical disc 3, that is, in the direction T that traverses the concentric or spiral tracks of the optical disc 3, by a moving means (pickup feeding mechanism) such as 6 or the like.

The optical pickup 4 houses a laser diode 7 as a light beam generating means, and the light beam generated by the diode 7 is focused through an objective lens 8 and irradiated onto the optical disc 3 as a beam spot. Ru. This objective lens 8 is movable in a direction T that traverses the tracks of the optical disc 3 and in a direction perpendicular to the surface of the optical disc 3 by applying a drive current to the lens actuator 9 via the control circuit 10. For example, by supplying a drive current to a tracking actuator constituting the (lens) actuator 9, it is possible to move in the track transverse direction T of the optical disc 3. Furthermore, by operating a tracking control system using a track error signal generated by receiving the return light from the optical disc 3, it is possible to track the current track.

On the other hand, by operating a focus control system using a focus error signal on the focusing actuator constituting the lens actuator 9, the distance between the objective lens 8 and the optical disc 3 can be maintained at a distance that provides a focused state.

Incidentally, FIG. 1 shows the configuration of a control system that performs track access by multi-track jump.

The light emitted from the laser diode 7 and returned from the optical disk 3 is received by a pin photodiode 11 constituting a 4-split detector, etc., and after being photoelectrically converted, its output is passed through a differential amplifier 12 to generate a track error signal. Tr is generated and input to the switch SW1 via the amplifier 13.

After the signal passing through the contact a of the switch SW1 is phase compensated through the phase compensation circuit 16, the adder 17 and the driver 1
By supplying the light to the tracking actuator (hereinafter abbreviated as "T" actuator) 19 via the optical fiber 8, the tracking control state can be set, and the light beam focused by the objective lens 8 can be made to track the current track. In this case, The signal passed through the phase compensation circuit 16 is supplied to V2V5 via a low-pass filter 211, phase compensation circuit 22, and driver 23, and this V2V5 is controlled by the track error signal Tr.The drive current supplied to this V2V5 is a current The track error signal Tr is detected by the detection circuit 24, amplified by the amplifier 25, and then input to the adder 17. Therefore, the track error signal Tr is used to control the movement of the objective lens 8 to track the target track. It is also used to control the overall movement (coarse movement) of the optical pickup 4 by V2V5.

In other words, in tracking control using only the objective lens 8 (T actuator 19), if the eccentricity of the optical disk 3 is large, it may be difficult to perform tracking within the movable range of only one Tr actuator. , by supplying the low frequency side signal of the track error signal Jr to 70M6, the optical disc 3
The optical pickup 4 is moved as a whole by driving V2V5 in accordance with the track movement due to the eccentricity of the optical disk, thereby absorbing the influence of the optical disk eccentricity. Also, in this case VCM
When 6 moves, its acceleration is detected by a current detection circuit 24 using a pickup coil (not shown), etc.
A part of the signal that drives the Tr actuator 19 is superimposed, and along with the movement of V2V5, the objective lens 8 is also moved.
Smooth tracking control is performed by suppressing relative acceleration between the V5 and the objective lens 8 and preventing the objective lens 8 from vibrating.

Due to the two-stage tracking control with the Tr actuator 19 and V2V5, even when the optical disk 3 is eccentric, the objective lens 8 can be kept in the tracking control state by restricting the movement range to only near the equilibrium position.

By the way, when accessing a target track from a current track, the target track can be accessed in a short time by using a multi-track jump.

When performing this multi-track jump, controller 3
1 outputs the jump command pulse itself or a switching signal synchronized therewith as shown in FIG. 3 (or FIG. 4) (a) to the switch SWI so that the contact side is turned on.

The controller 31 stores the address of the current track,
The difference from the address of the target track is calculated, and based on its sign, it is determined whether to jump from the current track to the inner track or to jump to the outer track, and the switching of the jump direction switching circuit 32 is controlled.

In other words, the polarity of the drive pulse for multi-track jump is changed depending on which direction it is. Therefore, the controller 31 is shown in FIG. 3 (or FIG. 4) ) (a
), the jump direction switching circuit 32, phase compensation circuit 33, switch SWI
, through the phase compensation circuit 16, one side supplies a jump drive pulse to the Tr actuator 19 via an adder 17 and a driver 18, and the other side supplies a jump drive pulse to the Tr actuator 19, and the other side passes through the PF 21, the phase compensation circuit 22,
A drive current pulse is supplied to V2V5 via the driver 23.

A part of this V2V5 drive current is supplied to the current detection circuit 24 and the amplifier 25, as in the case of the tracking control described above.
The signal is inputted to the adder 17 via 70M6, and the objective lens 8 is caused to generate an acceleration equivalent to the acceleration generated by the 70M6, thereby performing a track jump. This is thought to be due to the presence of eccentricity of the optical disc 3 at the time of track jump, and this effect can be eliminated by moving V2V5. Further, even when a large number of tracks are traversed during a multi-track jump, the jump can be performed without being affected by the movable range of the Tr actuator 19.

For example, when the light beam is moved by the Tr actuator 19 from a position close to the equilibrium position, if the moving teeth become large, the elastic member such as the spring that constitutes the Tr actuator 19 and holds the objective lens 8 movably approaches its elastic limit. It is expected that the movement of the objective lens tube with respect to the drive current will no longer be constant, and that the tracking response will change. Also, situations may occur where you are unable to jump to the target track and have to stop midway. On the other hand, by moving V2V5 in conjunction with each other as in this embodiment, such inconvenience can be eliminated.

During multi-track jumping of the objective lens 8 with the VCM 6 also being moved, the output signal of the differential amplifier 12 is passed through the amplifier 34 that amplifies the output signal, and is then passed through the comparator 35.
is input. The track error signal when passed through the amplifier 34 becomes a figure-8 waveform signal (denoted as TrS), as shown in FIG. 3 (or FIG. 4) (b). This signal TrS is waveform-shaped by the comparator 35 and becomes a binarized rectangular wave as shown in FIG. 3 (or FIG. 4) (C). This comparator 35 is constituted by a hysteresis comparator having hysteresis levels UT and LT, as shown by the dotted line in FIG. 3 (or FIG. 4) (a). The amplitude A of this signal TrS.

The hysteresis level UT (
or LT) to minimize the influence of noise. In other words, the hysteresis level is deepened to prevent counting errors. This hysteresis comparator is configured to perform positive feedback from the output terminal of the OP amplifier C1 to the non-inverting input terminal, as shown in FIG. Note that the level Vr in series with the resistor R1 is slightly higher than O. In this case, due to positive feedback, the level UT-Vr+VH
R1/(R1+R2) 侃VHRI/(R1+R2)
(Here, VH is the voltage level at °H'' at OP amplifier C1)
The output of 1 becomes "H", and the inverter C installed on the output side
2 and becomes "L II".

Therefore, for an input signal of a level exceeding the above UT, the output of the OP amplifier C1 becomes i L H1, and the output of the inverter C2 becomes "HTl." Due to this inversion, the OP amplifier C1, which has positive feedback of this output, Level LTχ-VLRI/(
JI L n until an input signal equal to or less than R1+R2) (where -■L represents the voltage level at L'') is applied.
hold. Note that the Zener diode Z provided on the output side of the OP amplifier C1 is used to make the binary output compatible with, for example, TTL (when the output of the OP amplifier C1 is L'', the input level to the inverter C2 is set to 0). It is desirable that the zener voltage is sufficiently low.(This zener diode 2
Instead, an ordinary diode may be connected with its anode connected to the ground side. ) The output of the comparator 35 is input to the counter 36 to count the rising edges and falling edges of the binarized pulse, and is also input to the frequency/voltage (F/V) converter 36 to convert the pulse according to the frequency. level voltage is converted.

The counter 36 is preset with a count value corresponding to the number of track jumps when the controller 31 performs a multi-track jump, and when this preset value is reached, it notifies the controller 31 that a predetermined number of track jumps have been performed. .

On the other hand, the converted output signal of the F/V converter 37 is input to a differential amplifier 38, compared with the reference voltage of a reference voltage generator 39, and the differential output component is added to the jump direction switching circuit 32. In addition, the input/output characteristics of the above F/V conversion converter (
FIG. 6(a) shows the F-V conversion characteristics. In this first embodiment, the F-V conversion characteristic has a negative characteristic in which the converted voltage level increases as the frequency decreases, so that it also functions as a kick pulse generation circuit. In other words, at the start of multi-track jump, the controller 31
By setting the polarity of the jump direction switching circuit 32, F
The level of the converted voltage of the /V converter 37 is at the maximum level at the start, and as shown in FIG. 6(b), the differential amplifier 38 and the jump direction switching circuit are used as drive pulses to track jump the converted voltage at the start, as shown in FIG. 6(b). After passing through 32nd mag, T”
It is supplied to the actuator 19 and VCM 6 side. (The driving pulse may be outputted from the controller 31 without being used also.) It goes without saying that the magnitude of this driving pulse must be larger than the maximum value of the track movement speed due to the eccentricity of the optical disk 3. be.

When the target track is accessed by switching to the tracking control mode after a multi-track jump, the reference voltage generator 39 generates a reference voltage VS corresponding to a track crossing speed close to the maximum value at which the target track can be stably pulled into the target track. is generated. (Here, the maximum value of this track crossing speed means the F/V converter 3
It is expressed as a voltage level converted by 7. ) That is, in the case of multi-track jumping, if the output of the F/V converter 37 at that time is maintained near the reference voltage VS, the track can be reliably pulled in.

After the multi-track jump starts, the objective lens 8 and the like move, and the output of the F/V converter 37 is determined according to the eccentricity of the optical disk 3 and the moving speed of the objective lens 8 and the moving speed of the 70M6. The level changes. The differential amplifier 38 detects the difference between this output level and the reference voltage VS level 39, and if there is a difference from the reference voltage Vs level, the feedback loop controls the level difference so that it becomes O, and the actual track The traverse speed is maintained at a speed corresponding to this reference voltage Vs.

By the way, in order to stably pull into the target track, switch to the tracking servo state before crossing the target track and pull into the target track. In this case, as the timing for setting the tracking servo state, it is desirable that the point at which the track error signal crosses zero after that timing corresponds to the target track.

This situation will be explained below with reference to FIGS. 3 and 4.

FIG. 3(b) shows the track error signal TrS when a multi-track jump (6 track jumps in this figure) is made to the inner circumferential side.

In this case, the current track is [and the target track (1+6)
This shows how to make a multi-track jump to a track. Actual track 1 in FIG. 3(b). I+1.1
+2. The crossing points of ... are zero crossing points in the upward-sloping waveform portion.

The track error signal TrS is counted as shown in FIG. The range in which servo pull-in is possible starts from a point P1 where the track error signal TrS reaches a negative peak, that is, a quarter wavelength before the target track (1+6).

Therefore, the counter 36 inputs the track error signal Tr5 by 2.
The rising and falling edges of the converted signal are counted twice as many as the number of tracks up to the target track, and then a multi-track jump signal of a predetermined number of tracks is output to the controller 31, and the controller 31 receives this. The track jump command pulse is released and the switch SW1 is switched to the tracking servo mode in which contact a is turned on.

There is a slight time delay from the output of the counter 36 until the controller 31 switches the switch SW1, and due to this delay, the timing at which the switch SW1 enters the tracking servo mode is after P mode in FIG. (That is, 1/
Track pull-in is performed 4 wavelengths before. ) Therefore, by switching to the lower tracking servo mode, the tracking error signal TrS is pulled into the position where it crosses zero, that is, the target track, and it is possible to stably pull into the target track.

The second reason for increasing the hysteresis of the comparator 35 is that this hysteresis allows the time when the counter 36 has counted a predetermined number of counts to be set sufficiently close to the time when the target track can be pulled into the target track. . (If it is just a zero cross, it will be further 1/4 wavelength short of the tracking servo retractable range, and if you immediately switch to tracking servo mode,
Unable to pull into target track. ) That is, when performing a track jump in the inner circumferential direction, the upper right portion is an area where the track can be pulled in, and the lower right portion is an area with reverse characteristics. Therefore, if the hysteresis is made deeper, when the count number reaches a predetermined value and the jump drive signal is cut off, the track pull-in possible area is approached, so that the track pull-in can be carried out more stably. (Conversely speaking, it becomes easier to escape from the opposite characteristic area.) On the other hand, when moving in the outer circumferential direction, the downward-sloping part to the right becomes the track pull-in area, contrary to the case of moving in the inner circumferential direction. In this case as well, the device is operated at a similar hysteresis level, and a signal for on-tracking at a wavelength before 1/4 wavelength is output.

(Switch to tracking servo mode.) In the case of this movement in the outer circumferential direction, the comparator 35 does not operate for the first half-wavelength of the tracking error signal (the level LIT is not exceeded at this half-wavelength), so the comparator output Binarized pulses do not appear. Therefore, the jump stop timing is executed after counting 2N-1, which is one less. (For example, from the controller 31 to the counter 36
The preset value is 2N for inner movement.

When moving to the outer periphery, set 2N-1 to obtain a good %,
, ) By the way, after jumping to the target track on the outer circumferential side, the output of the comparator 35 becomes "H". If a track jump is performed in the inner circumferential direction with the next jump command, after a count of 12 (2N in general) as shown in Fig. 7(d), as shown in Fig. 7(e). Since the jump command pulse is canceled, the on-track command is output with the reverse characteristic of the track error signal @TrS, and there is a high possibility that on-tracking will fail, and the accuracy of the jump number will also deteriorate. For this reason, in this embodiment, a reset pulse generation circuit 40 is provided as shown in FIG. 1, and the falling portion at the start of the jump command pulse is differentiated to generate the pulse RP shown in FIG. 7(f). By applying the voltage to the input terminal of the comparator 35, the output of the comparator 35 becomes "off", and when the track error signal TrS exceeds the level LIT, II
It is designed to be able to detect H11.

According to the first embodiment, when performing a multi-track jump, the track error signal TrS is binarized,
A multi-track jump is performed to 1/4 wavelength before the target track, and the frequency of the track error signal at that time is detected to detect the actual track crossing speed (including the eccentricity of the optical disk), and the crossing speed is determined to be a constant speed. A means for controlling the moving speed (crossing speed) is formed.

With this movement speed control means, even if the optical disk 3 is eccentric, the eccentricity can be compensated for and maintained at a constant transverse speed. Since this crossing speed is a speed at which truck retraction is possible, stable truck retraction can be performed when the jump command is canceled and the mode is switched to the truck servo mode.

Further, in this embodiment, when performing a multi-track jump, a drive signal is applied to the Tr actuator 19, and a part of the drive signal is also applied to V2V5, so that V2V5 is also interlocked with the Tr actuator 19, so that the 7r actuator No. 19 - Track jumps over a wide range can be performed with one multi-track jump without being restricted by the range of motion.

FIG. 8 shows the main parts of a second embodiment of the present invention.

This embodiment differs from the first embodiment shown in FIG. 1 in that the output of the counter 36 is input to the controller 31 via a delay element 41.

That is, in the first embodiment, the counter 36 has a predetermined number (
The counted output (preset number) is input to the controller 31, and in response to this, the controller 31 cuts off the jump command signal and performs servo pull-in.
In this embodiment, after the counter 36 counts a predetermined number, the delay element 41 inputs the jump command pulse to the controller 31 after a predetermined delay time Δt, and then the controller 31 turns off the jump command pulse (that is, controls the on/off of the switch SW1). (to do)

The operation in this case is as shown in FIG.

By performing the above delay, it becomes possible to turn on the tracking servo within the track lead-in area, that is, at a portion closer than 1/4 wavelength of the designated track.

In this embodiment, the output of the counter 36 is delayed, but the signal for switching the switch SW1 may be delayed by the controller 31.

FIG. 10 shows a control system of a third embodiment of the present invention.

In this embodiment, in the eleventh embodiment shown in FIG.
1 is used.

In the reference voltage setting circuit 5'1, when performing a multi-track jump, the reference voltage is set to a small value so that a high relative speed is achieved up to M tracks before the target (designated) track (see Fig. 11 (C)). , thereafter, the reference voltage VS is switched to a higher one so that the relative speed becomes lower.

According to this embodiment, when N-Ml-racks, which is the number of tracks to be moved N minus M, are counted, the reference voltage setting circuit 51 is set to a high reference voltage Vs. This circuit 5
1 is a reference voltage source ■S and a resistor r1 as shown in FIG.
．． r2. It can be easily configured with r, capacitor CI, c, and switch S.

Therefore, when a multi-track jump is performed, the track error signal TrS is moved at a fast moving speed up to the number of N-M tracks as shown in FIG. Therefore, braking is applied to the moving speed, the speed is gradually reduced, and the predetermined moving speed is reached, after which the vehicle is on-track.

According to this embodiment, the target track can be accessed in a short time.

Note that the reference voltage generation circuit 51 may be configured to be switched according to the number of tracks to be multitrack-jumped. For example, when the number of tracks to be crossed is large, the reference voltage is lowered to allow high-speed track jumping, and in the latter half, the reference voltage is increased to enable track-crossing to be performed at low speed. Further, when the number of tracks to be crossed is small, the track crossing is performed at a low speed that allows the trucks to be pulled in from the beginning. Further, in the case of a medium number of tracks to be crossed, the track may be crossed at a medium speed (or high speed) using a medium reference voltage, and then the track may be pulled in at a low speed.

Note that the pickup feeding mechanism is not limited to V2V5.

[Effects of the Invention] As described above, according to the present invention, when making a track jump, the pickup feed mechanism is moved together with the Tr actuator, so that the T
A wide range of track jumps can be performed in one track jump without being restricted by the movable range of the r actuator.

[Brief explanation of the drawing]

FIGS. 1 to 7 relate to the first embodiment of the present invention.
The figure is a block diagram of the track access means in the first embodiment, FIG. 2 is an overall block diagram of the first embodiment, FIG. An explanatory diagram of multi-track jump to the outer circumference side, Fig. 5 is a circuit diagram of a comparator with hysteresis characteristics, Fig. 6 is a diagram showing the characteristics of an F/V converter, and Fig. 7 is a track jump to the outer circumference side. 8 is a configuration diagram showing the main part of the second embodiment of the present invention. FIG. 9 is an explanatory diagram of the operation of the second embodiment. FIG. 10 is a block diagram of a track access means in a third embodiment of the present invention, and FIG. 11 is an explanatory diagram of the operation of the third embodiment. 1... Optical recording and reproducing device 3... Optical disc 4... Optical pickup 6
...VCM 7...Laser diode 8...Objective lens 9...Lens actuator 11...Pin photodiode 12...Differential amplifier 19...Tracking actuator 31...Controller 32 ... Jump direction switching circuit 35, ... Comparator 36 ... Counter 37
...F/V converter 39...Reference voltage generator 1? D. Figure 1 Figure 2 I Figure 5 N6 Figure 1!1 Tanmoku P1 Sha Figure 10

Claims (1)

[Claims] Means for generating a light beam; Beam projection means for directing and projecting the light beam onto a recording medium; and Moving the projected light beam in a direction across tracks of the recording medium. a first moving means; a second moving means for moving the first moving means in a direction across tracks of the recording medium; and a first and second moving means for moving the light beam to a desired track. and first and second drive signal generating means for generating first and second drive signals to be applied to the moving means, and the first moving means is driven by the first drive signal. An optical recording/reproducing apparatus characterized in that the first drive signal is applied to the second moving means at a time.