JP3394427B2 - Disc playback device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing apparatus provided with a slide feed motor for feeding a slide portion having a pick-up in a radial direction of the disc when reproducing information recorded on the disc. is there.

[0002]

2. Description of the Related Art For example, a compact disc (hereinafter referred to as a CD
Disk) or the like as a recording medium of a computer or the like is widely used. When the information recorded on such a disc is reproduced by the disc reproducing apparatus, it is necessary to send a pick-up in the radial direction of the disc in order to reproduce the information from a desired position on the disc. .

For this operation, there is a disk reproducing apparatus provided with a slide portion on which a pick-up is mounted and equipped with a slide feed motor for moving the slide portion as described above. That is, the slide part on which the pick-up is mounted is composed of the pick-up and a housing for covering it. A lens is provided in the pick-up. An actuator coil and a magnet used for tracking servo are provided in the housing. The slide feed motor is provided as described above, and the pick-up is fed in the radial direction of the disc by moving the slide portion together with the slide feed motor.

As a slide feed motor as described above, a linear motor is used in some middle and high class machines. However, the slide feed by the linear motor complicates the circuit of the speed control system and requires a high-precision feed mechanism, resulting in high cost. Moreover, power consumption increases when trying to realize a high-speed search.

Therefore, in a conventional popular disc reproducing apparatus, a DC brush motor combined with a rack and pinion mechanism, a ball screw, a spur gear, etc. is used as a pick-up slide feed motor.

As shown in FIG. 14, in the slide feed at the time of reproduction by the DC brush motor, the tracking actuator coil 71a of the pick-up 71 is used.
BTL (Balanced Transformer Less) for driving
) Input signal TRD (Tracking Driv) to the driver 72
e Signal: hereinafter referred to as TRD signal),
The low frequency component is taken out through the filter 73b, and this signal drives the slide feed motor 75 via the slide motor driver 74. As a result, the slide portion carrying the pick-up 71 is slide-fed. L71 is a tracking servo loop. L72 is a slide feed motor servo loop.

A high-speed search by slide feeding is called a rough search. In order to perform a rough search using a DC brush motor, a method called a track count as shown in FIG. 15 is generally used, which will be explained.

1. First, the tracking servo is turned off at the start point (point a). 2. The rotation of the slide feed motor 75 in a predetermined direction is started (point b). 3. Set the counter that measures the track cross signal (point c). 4. When the counter reaches a predetermined value by the track cross signal, the slide feed motor 75 is stopped (d
point). 5. The tracking servo is turned on (point f) after waiting for the slide portion to sufficiently stop due to the back electromotive force brake of the slide feed motor 75 and the loss torque of the slide mechanism (the period indicated by e). It is done in the procedure.

A method of obtaining the amount of movement of the slide portion by the number of crossing tracks on the disk is called a track counting method. In the DC brush motor, the track / count coarse search is thus performed with relatively easy control.

On the other hand, in many cases, a coarse search generally called an FG (Frequency Generation) method is adopted. In contrast to the track counting method described above, in this FG method, as shown in FIG. 16, a signal proportional to the number of rotations of the slide feed motor 75 is transmitted from a disc-shaped reflection plate or transmission plate attached to the feed motor shaft. It is generated by the photodetector 79 or the like. Hereinafter, this signal is referred to as an FG signal. This F
The FG method is to obtain the amount of movement of the slide part from the relationship between the G signal and the gear ratio from the slide feed motor 75 to the slide part. And 4. The FG method can be explained by replacing the track count signal in the section with the FG signal.

In any of the above-described coarse searches, the accuracy is inevitably low as will be described below.

1) A resolution DC brush motor according to the gear ratio of the mechanism by the cogging torque of the slide feed motor is shown in FIG. 17 or FIG.
As shown in FIG. 8, the slide feed motor 91 tries to stop at the point of competition by the magnetic force between the rotors 91a, 91b, 91c and the magnets 92, 93. That is, the rotor and the magnets 92 and 93 shown in FIG. That is, the rotors 91a and 91b are opposite the magnet 92.
One of 91c stops, or one of the rotors 91a, 91b, 91c tries to stop opposite the magnet 93. In addition, the rotors 91a and 91 shown in FIG.
Due to the positional relationship between the b / 91c and the magnets 92/93, the same attempt is made to stop at six opposing points. That is, either the rotors 91a, 91b, or 91c are stopped so that one of the rotors 91a, 91b, and 91c is disposed just above the middle of the magnets 92 and 93, or the magnets 92 and 9 are stopped.
The rotors 91a and 91 are located on the lower side in the figure, just in the middle of FIG.
Trying to stop so that either b. 91c is arranged. The characteristic of the motor that tries to stop at the counterpoint due to the magnetic force is called cogging torque. Next, if the gear ratio of the slide feed mechanism is set to 1.2 mm / 1 rotation, for example, the cogging torque of the motor results in 12 divisions, so 0.1 mm is the resolution of the slide feed mechanism. . Here, an error of ± 50 μm occurs.

2) Backlash of Mechanism Gear Backlash In the gear of the slide feed mechanism, backlash required due to the precision of the parts occurs unless a special design for eliminating backlash is made. If this backlash is 100
If it is μm, an error of ± 50 μm occurs here.

3) As an example of an eccentric CD by a disc and its chucking mechanism, the eccentricity is 70 μ according to the standard of CD.
However, the chucking mechanism also causes eccentricity. If the total amount of this eccentricity is 100 μm, an error of ± 100 μm occurs here.

As described above, when combined, it is about ± 200 μm.
Error of.

Therefore, the search is carried out by using not only the above-mentioned rough search but also a precise search. As such a precise search, generally, a precise search called a lens kick method performed on a CD or the like is used (hereinafter referred to as a lens kick search).

The lens kick search is different from moving the entire slide portion equipped with the pick-up as described above. That is, the pick-up part equipped with a lens as a movable part is driven by an actuator coil and a magnet provided in the housing used for tracking servo, and only the information tracks of a predetermined number of discs are driven. It is something to move.

[0018]

In order to realize a high-speed search, it is necessary to shorten the time required for the coarse kick search as well as the time required for the lens kick search as a precise search. However, as described below, in the above-mentioned conventional technique, it takes time to perform a lens kick search so as not to deteriorate the performance of reading information from a disc, and a high-speed search cannot be performed. There is a problem.

That is, the pick-up has a performance standard called a safe movable range in the radial direction of the disk of the movable part,
For example, in the case of a CD, it is about ± 300 μm to ± 500 μm, and if the movable part of the pick-up, that is, the lens or the like is tilted beyond this range, the information reading performance deteriorates. Therefore, it is necessary to read the information within the safe movable range of the movable portion.

However, conventionally, the actual position information in the slide portion of the movable portion of the pick-up cannot be known. Therefore, it is very difficult to accurately perform the combined use of the slide feed during the lens kick search in accordance with the kick movement amount. Note that, generally, combined use of slide feed during lens kick search is called kick assist. Therefore, in the past, kick assist was not performed,
Instead, perform a lens kick at a very ambiguous position,
As a result, when the movable part is separated from the free center position to some extent, the next slide feeding operation is repeated. However, in this way, when it is necessary to perform a continuous lens kick search, immediately after each lens kick search, it is determined whether or not the feed motor needs to be driven for the slide feed. However, if necessary, you need to wait for the time it takes to do it before doing the next lens kick search.
Therefore, high speed search cannot be performed.

Alternatively, as described above, since the actual position information in the slide portion of the movable portion of the pick-up is not known, conventionally, after sufficient feeding is performed by the slide feeding servo, that is, a sufficient waiting time is given. After that, a method of taking a lens kick is adopted. For this reason,
It takes time for the slide feed. Therefore,
High speed search is not possible.

The slide feed servo generally has a relatively large time constant. One is the time constant of the slide feed motor itself. Also, as shown in FIG. 14, the low-pass filter 73 in the LSI 73 is
The slide motor driver 74 is driven by the signal passed through b, and the time constant of the low pass filter 73b exists. Therefore, when the lens kick is performed after the sufficient feed is performed by the slide feed servo as described above, it takes time correspondingly due to the influence of these time constants. That is, immediately after the coarse search, determine whether or not the feed motor needs to be driven for slide feed, and if necessary, wait a little while to execute it and then perform the lens kick search. Need to do. For example, a DC brush motor as a slide feed motor has a time constant of 20 msec to 60 msec. In addition, for example, if the low pass filter 73
If the cutoff frequency of b is 1 Hz, a delay of 125 msec occurs. On the other hand, if the cutoff frequency of the low-pass filter is increased to several tens of hertz in order to reduce this delay, the slide feed servo will try to follow the eccentricity of the disk etc. There is a movement, that is, a movement back and forth in both directions with respect to the free center position of the movable portion of the pick-up. Therefore, the high speed search is not possible.

In general, the pick-up vibrates during the rough search. Due to this vibration, when the tracking servo is pulled in at the time of completion of the rough search, the pick up is not always pulled in the vicinity of the center within the safe movable range, and may be deviated from the vicinity of the free center. Therefore, the effective safe movable range that can be used as a lens kick is reduced. In order to avoid this, it is necessary to provide a weight and perform slide feeding before performing the next precise lens kick search. Therefore, the high speed search is not possible.

[0024]

In order to solve the above-mentioned problems, a disk reproducing apparatus according to a first aspect of the present invention is configured such that a pick-up having a movable part is mounted on the slide part, and the slide part is provided in a radial direction of the disk. And a lens kick search for moving the movable part of the pick-up in the slide part in the radial direction of the disc with a predetermined free center position in the slide part as the center of movement. and a lens kick search means for performing, in the sliding portion, the pick-up in the disc reproducing apparatus having a safety movable range as the position of the moving part can be read correctly information from the disk, known When there is a certain amount of movement of the moving part
, A predetermined high frequency component from the pick-up drive signal
The tracking position signal, which is the signal excluding
The drive sensitivity of the above-mentioned movable part expressed as
With degrees, position detecting means for detecting a position of the movable portion in <br/> the slide portion for each tracking position signal, the movable detected by said position detecting means
Based on the position information of the section, the slide feeding means for performing the slide feeding in the same direction as the lens kick search during the lens kick search so that the movable section is located within the safe movable range. Is provided.

With the above arrangement, slide feed is performed as a rough search in order to place the pick-up at the reproduction position of the disc. Next, at the time of lens kick search as a precise search, in parallel with that, pick
While detecting the actual position information of the up movable portion in the slide portion, as a kick assist, slide feeding is performed so that the movable portion is positioned within the safe movable range.

Therefore, after performing the lens kick search, it is not necessary to determine whether it is necessary to drive the feed motor for the slide feed or to execute the determination.

Further, it is not necessary to perform sufficient feed by the slide feed servo before performing the lens kick search, and the time for the slide feed is unnecessary.

Further, since it is not necessary to sufficiently feed the slide feed servo before performing the lens kick search, the lens kick search is not affected by the time constant of the slide feed servo.

Even when the pick-up is displaced from the vicinity of the free center due to the vibration of the pick-up during the rough search, the slide feed is performed as described above when the lens kick search as the fine search is performed. Since the gap is eliminated, there is no need to perform slide feed before the lens kick search.

Therefore, high-speed search can be performed while preventing deterioration of the performance of reading information from the disc.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the control means causes the movable portion to fall within the safe movable range based on position information in the slide portion of the movable portion. In order to do so, the movable maximum value of the movable part is obtained for each of the outer and inner radial directions of the disc, and the above-mentioned value is set so that the movement amount by the lens kick search falls within the maximum value. It is characterized by controlling the lens kick search means.

With the above-mentioned structure, the lens / lens is controlled within the maximum value for keeping the movable portion within the safe movable range.
Kick searched. After the lens kick search, the movable part is always located within the safe movable range.

Conventionally, since the actual position of the movable part in the slide is not known, and therefore kick assist is not performed, the movable part should be moved far beyond the above range. It is set. Therefore, the lens kick search cannot be performed for a very long distance. On the other hand, in the above configuration, the maximum value of the moving amount of the movable portion is obtained so that the movable portion enters the safe movable range after the movement as described above. It can perform lens kick search over a long distance. For this reason, the probability of reaching the target location by one lens kick search increases.

Therefore, in addition to the effect of the structure of claim 1, it is possible to perform a faster search while preventing the deterioration of the performance of reading information from the disc.

According to a disk reproducing apparatus of a third aspect, in addition to the structure of the first aspect, the movable portion is a disc inside the slide portion.
Lens kick on the inner or outer circumference of the disc
・ If you move to the same side in search,
The amount of movement of the slide part can be within the safe movement range above.
When performing a lens kick search so that the moving part fits
The feature is that the amount of movement is larger than the amount of movement of the movable portion .

With the above structure, the lens kick
The amount of slide feed performed during the search is the same as the amount of movement of the movable part when a lens kick search is performed so that the movable part fits within the safe movable range according to the position of the movable part within the slide part. , Larger amount, smaller amount, and so on.

Therefore, when the movable part is located on one of the inner circumference and the outer circumference of the disk in the slide part and moves to the same side in the lens kick search as the moving amount of the slide part, If the amount of movement of the movable part is larger than the amount of movement of the movable part when the lens kick search is performed so that the movable part fits within the safe movable range, the slide part is moved more than the moving amount of the movable part after the lens kick search. It can be moved greatly. As a result, the safe movable range is apparently expanded. Therefore, the lens kick search for a long distance can be performed at one time, and the probability of reaching the target location by one lens kick search is increased.

Therefore, in addition to the effect of the structure according to the first aspect, a higher speed search can be performed while preventing the deterioration of the information reading performance from the disk.

According to a fourth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, the control means is such that the movable portion is within the safe movable range before the lens kick search. It is characterized in that if it does not exist, if it does not exist, the slide feeding means is controlled so as to perform the slide feeding until the movable portion is positioned within the safe movable range.

With the above construction, when the lens kick search is started after the rough search is finished, it is first checked whether or not the movable portion is within the safe movable range, and if not, the lens kick search is performed. Before starting, the slide feed is performed so that the movable portion is within the safe movable range.

Therefore, at the start of the lens kick search, the movable portion is always within the safe movable range. As a result, a long distance lens kick search can be performed. For this reason, the probability of reaching the target location by one lens kick search increases.

Therefore, in addition to the effect of the structure of claim 1, it is possible to perform a faster search while preventing the deterioration of the performance of reading information from the disc.

[0043]

DETAILED DESCRIPTION OF THE INVENTION

[First Embodiment] The following will describe one embodiment of the present invention with reference to FIGS. 1 to 9.

First, FIG. 1 shows a block diagram of a disk reproducing apparatus according to the present embodiment. 1 is pick up, 2
Is the pick-up 1 radial actuator 1a
It is a driver amplifier as an actuator driver that drives the. A servo LSI 3 includes a tracking equalizer amplifier 3a, a tracking error waveform shaping amplifier 3b, a low-pass filter 3c, and the like. Tracking equalizer
The amplifier 3a outputs the tracking drive (TRD) signal input to the input terminal a of the driver amplifier 2.

Reference numeral 8 is an RF amplifier for amplifying the tracking error signal from the pick-up 1.

Further, a feed motor 5 and a motor driver 4 for supplying a drive voltage (Vm) for the feed motor 5 are provided.

6 is a low-pass filter, and 30
The cut-off frequency is set to about 0 Hz to 600 Hz. Reference numeral 7 is a control microcomputer, and a track cross (TCRS) signal as an input signal enters a counter input terminal b of the control microcomputer 7, and a traverse drive (TV
The D) signal and the tracking position (TRP) signal enter the A / D input terminals c and d of the control microcomputer 7, respectively. The TVD signal is a signal in which the TRD signal is output through the low pass filter 3c. The TRP signal is TR
The D signal is the signal output through the low pass filter 6.

From the D / A output terminals e and f of the control microcomputer 7, a traverse, which determines the drive voltage of the feed motor 5,
A drive output (TVDO) signal and a play window (PLM) signal that determines the drive voltage application time of the feed motor 5 are output. The PLM signal is input to the analog switch 9, whereby the TVDO signal applied to the motor driver 4 is turned on / off to control the motor driver 4.

By the pick-up 1, the RF amplifier 8, the driver amplifier 2, and the servo LSI 3,
A tracking servo loop L1 is formed. Further, the RF amplifier 8, the servo LSI 3, the control microcomputer 7,
The analog switch 9, the motor driver 4, and the feed motor 5 form a slide feed motor servo loop L2.

The low-pass filter 6 and the control microcomputer 7 constitute a position detecting means. The control means is composed of the control microcomputer 7 and the analog switch 9.

As shown in FIG. 2, with respect to the disk 21 and the disk center 21a, the movable part 2 of the pick-up 1 is moved.
A slide portion 22 having the housing 4 mounted in the housing 23 is provided. The movable portion 24 is composed of a lens or the like for condensing the reproduction light beam at the reproduction position of the disc.

The slide portion 22 is movable in the radial direction of the disk 21 indicated by the arrow in the figure by a slide feeding operation.

The movable portion 24 is movable in the housing 23 in the radial direction of the disk 21. For example, as shown in FIG.
On the other hand, the two springs 25 and 26 are connected in the radial direction of the disk, which can be considered as expansion and contraction of these springs. In the figure, M is the free center position of the pick-up, which indicates the center of the movement of the movable part. However, this movement is actually not a parallel movement as described in the section of the prior art, but is performed by tilting the movable portion 24 with respect to the disk 21.

One of the movable ranges of the movable section 24 is a physically movable area which does not collide with the housing 23 and other members in the slide section 22 as the maximum possible range of the system. There is.

On the other hand, if the movable portion 24 is moved too much as described above within the maximum possible range of the above system, that is, the lens or the like is actually tilted too much with respect to the disk 21. And the disk 21
The reproduction information signal taken out from the device deteriorates. Therefore,
The moving area of the movable portion 24 of the pick-up 1 where such deterioration does not occur is referred to as a safe movable range. For example, in a general CD (compact disc) pick-up, the safe movable range is ± 300 μm to ± 500 μm.

Next, the lens kick search operation will be described. Fig. 3 shows a conceptual diagram of a search by a pick-up lens kick. The lens kick search is a movement of the movable part of the pick-up. Tracking is turned off at point A in FIG. 7A, and the TRD signal for driving the movable portion 24 of the pick-up 1 is output by the servo LSI 3 in FIG. Jump the number of tracks.

At this time, the movable portion 24 of the pick-up 1 is displaced from the free center position M by the search by the lens kick. In order to reduce this displacement, slide feeding is performed in parallel with the lens kick as follows. That is, immediately after the search by the lens kick is started at the point A, the TVDO signal and P shown in FIGS. 3 (e) and 3 (d) output from the control microcomputer 7 of FIG.
The motor drive signal is input to the motor driver 4 via the analog switch 9 by the LM signal, and the drive voltage Vm is applied to the feed motor 5 as shown in FIG.
It costs. Then, as shown in FIG. 3B, the slide feed speed Vs changes, and the slide portion 22 carrying the pick-up 1 moves in parallel with the lens kick operation. This is hereinafter referred to as lens kick assist.

The TVDO signal and the PLM signal output from the control microcomputer 7 can be freely set by software. That is, the drive voltage V applied to the feed motor, which is obtained by the feed motor and a certain mechanism shown in FIG.
As in the example of m, its application time, and the amount of slide feed movement, the desired amount of slide feed movement is obtained by combining the drive voltage Vm applied to the feed motor and its application time. Therefore, by knowing the displacement of the movable portion 24 of the pick-up 1 caused by the lens kick search from the free center position M, the slide feed can be performed by the displacement.

Further, by changing the TVDO signal while the PLM signal shown in FIG. 3D is standing, various feed motor drive waveforms as shown in FIGS. 5 and 6 can be created. As a result, it becomes possible to control the movement amount of the lens kick assist and the acceleration to the pick-up during the lens kick assist in a wider range.

Next, the movable part 24 of the pick-up 1
A method of knowing the actual position in the slide portion 22 will be described. First, the details of the method and means for detecting the drive sensitivity (radial actuator sensitivity) of the pick-up 1 when driven by the driver amplifier 2 will be described.

The drive sensitivity of the pick-up referred to here is
Generally, it is defined by the signal voltage (unit: V: volt) applied to the radial actuator 1a of the pick-up 1 and the amount of movement (unit: mm: millimeter) in the radial (radial) direction of the pick-up 1 due to the signal voltage. . TR output from the tracking equalizer amplifier 3a
The D signal becomes a drive signal for the pick-up 1 via the driver amplifier 2. Therefore, this drive signal is
The signal level changes depending on the drive sensitivity of the pick-up 1.

On the other hand, the TRP signal passed through the low-pass filter amplifier 6 is the A / D input terminal d of the control microcomputer 7.
Is taken in. This signal is a signal excluding the high frequency components included in the TRD signal, and if the drive sensitivity of the pick-up 1 is known, it indicates the amount of radial movement of the pick-up at that time. If the amount of movement of the pick-up 1 in the radial direction (radial direction) of the disk is known, the signal is proportional to the drive sensitivity of the pick-up 1 and thus represents the drive sensitivity.

Therefore, a known fixed amount of pick-up movement in the radial direction, that is, displacement can be given, and a signal having a good S / N ratio, that is, input to the A / D input terminal d of the control microcomputer 7. If the value of the TRP signal generated can be known, the drive sensitivity of the pick-up 1 can be known.

This fixed amount of displacement can be given by the lens kick search without the above-mentioned lens kick assist. For example, with a CD, 63 lens kick searches can give a known amount of displacement of about 100 μm. This situation will be described with reference to FIGS. 7 and 8.

In FIG. 7, the horizontal axis represents time. Vertical axis is TRP
It is the value of the signal, which will also represent the position of the movable part 24 within the slide 22. That is, when the TRP signal is "0", the movable part 24 of the pick-up 1 is
Is located at the free center position M. A positive value indicates that the movable portion 24 of the pick-up 1 is located at a position displaced from the free center position M in the inner circumferential direction. If the value is negative, pick up 1
The movable part 24 is located at a position displaced from the free center position M in the outer peripheral direction.

As shown in FIG. 8, in reality, the disc 2
1 has an eccentricity H with respect to the perfect circle 30 due to the disc and the disc chucking mechanism. The amount of eccentricity H is
For example, in the case of a CD, the maximum is 70 μm.

Due to the presence of this eccentricity H, as shown in FIG. 7, the sampling of the TRP signal is carried out during a period of one cycle of the disc (T in the figure is determined by the number of revolutions of the disc).
(Shown by 1) and obtain the average value of the obtained values. T1
Represents the acquisition time of the TRP signal. Then, as described above, a predetermined amount of displacement is given to the pick-up 1 for a predetermined period (indicated by T2 in the figure). This T2 represents the operating time of the lens kick. After this, similarly, the TRP signal is sampled for a period of one cycle of the disc (indicated by T3 in the drawing), and the average value of the obtained values is obtained.
T3 represents the acquisition time of the TRP signal. In the figure,
It shows a case where the movable portion 24 of the pick-up 1 is displaced from the free center position M in the negative direction, that is, the outer peripheral direction of the disk by the operation of the lens kick, and the straight line P in the figure indicates a period T3. The average center position of the movable portion 24 is shown.

TR of sampling before or in the period T1
The difference between the average value of the P signal and the sampling average value of the later period, that is, the period T3 is calculated. Based on the calculation result using the difference between the average values of the TRP signals and the above-mentioned known displacement,
You can see the driving sensitivity of Up 1.

Further, the previous sampling result is stored in the control microcomputer 7, and the total amount of eccentricity can be known from the difference between the maximum value and the minimum value and the driving sensitivity of the pick-up 1 described above. it can.

As described above, by taking in the TRP signal from the drive sensitivity of the pick-up 1 by the control microcomputer 7, the actual position in the slide-up part of the pick-up, such as immediately before and after the search by the lens kick, is performed. Will have the means to know.

Next, it is necessary to read the reproduction information within the above-mentioned safe movable range of the pick-up 1, that is, within the area where the information signal taken out from the disk does not deteriorate. There's a problem. 1. When assisting the search lens kick, the mechanism has a gear system play called backlash, which may make accurate lens kick assistance impossible. 2. Immediately after performing a lens kick search, the target information track may sometimes arrive outside the safe range of pick up, and at this time the correct information cannot be read due to deterioration of the information signal. , The coarse search will be started again. If this happens, this retry will result in a delay in the total search time.

In order to solve such a problem, in the present embodiment, when performing the lens kick search after the rough search, the inside of the slide portion 22 of the movable portion 24 of the pick-up 1 described above. Using the TRP signal indicating the actual position and the software in the control microcomputer 7, the actual position of the movable part 24 in the slide part 22 is known as described above, and the pick-up is performed as follows. In this way, the search operation is ensured within the safe movable range, and the high speed search is realized by solving the above problem. This situation is shown in the flowchart of the safe movable range search in FIG.

1. The movable range of the pick-up obtained by subtracting an uncertain factor such as the backlash of the mechanism in advance is set as the movable range of the pick-up (safe movable range) on the software (S1). 2. A rough search is performed (S2). 3. The position information is read from the information track (S3). 4. It is determined whether the search target has been reached (S4). Normally, the target is not reached in the rough search, so the routine proceeds to S5. 5. While assisting kicks in parallel, a search is performed with a lens kick within the maximum physically possible track jump number assumed by the system (S
5). Next, return to S3. 6. If the search target is reached in S4, the TRP signal is read (S6). 7. It is determined whether it is within the safe movable range (S7), and if it is within the safe movable range, the search is completed (S9). 8. If it is within the non-safe movable range in S7, a waiting time is provided and slide feeding is performed by the feed servo (S8).

As described above, in the present embodiment, when performing the lens kick search after the rough search, the TRP signal indicating the actual position in the slide portion 22 of the movable portion 24 of the pick-up 1 is used. The software in the control microcomputer 7 is used to know the actual position of the movable portion 24 in the slide portion 22, and the search operation in the safe movable range of the pick-up 1 is ensured. While realizing the high-speed search, at the same time, the pick-up 1 is positioned within the safe movable range, and it is possible to read the reproduction information well.

[Second Embodiment] The following will describe another embodiment of the present invention in reference to FIGS. 10 and 11. In addition, for convenience of explanation, a member having the same function as the member shown in the drawings of the above-mentioned embodiment,
The same reference numerals are given and the description thereof is omitted.

In this embodiment, the structure of the apparatus is the same as that of the first embodiment, but the contents of the high speed search are slightly different. The high-speed search in this embodiment is shown in the flowchart of the safe movable range search in FIG.

1. The movable range of the pick-up in which an uncertain factor such as the backlash of the mechanism is subtracted in advance is set as the safe movable range of the pick-up on the software (S11). 2. A rough search is performed (S12). 3. The position information is read from the information track (S13). 4. It is determined whether the search target has been reached (S14). Normally, the target is not reached in the rough search, so the routine proceeds to S15. 5. The TRP signal is read and the number of allowable track jumps within the safe movable range is calculated (S15). 6. The maximum allowable number of track jumps is compared with the number of track jumps to the target, and a search within the maximum allowable number of track jumps to the target is executed while assisting kicks in parallel (S16). Next is S13
Return to. 7. If the search target is reached in S14, the TRP signal is read (S17). 8. It is determined whether it is within the safe movable range (S18), and if it is within the safe movable range, the search is completed (S20). 9. If it is in the non-safe movable range in S18, a waiting time is set and slide feeding is performed by the feed servo (S19).

In this way, the maximum number of track jumps that can be executed from the actual position within the pick-up slide portion is calculated each time. The effect of performing such calculation will be described with reference to FIG.

In FIG. 11, reference numeral 35a indicates the free center position M. Reference numeral 35b indicates an inner peripheral side region of the safe movable range. Reference numeral 35c indicates an outer peripheral region of the safe movable range. 31a, 31b, and 31c are picks,
It represents the actual position of Up 1. That is, 31a
31 if Pickup 1 is in the free center position M
Reference numeral b represents the case where the pick-up 1 is in the inner peripheral area of the safe movable range, and reference numeral 31c represents the case where the pick-up 1 is in the outer peripheral area of the safe movable range.

When the pick-up position immediately after the rough search is near the free center position like the position 31a,
The next lens kick search is allowed evenly in both safe movable ranges on the outer circumference. This is similar to the conventional search of a system that does not know the pick-up position, but in the past, some margin is added to avoid a large deviation from the safe movable range. The actual situation is that it allows only a few track jumps for its size.

When the position of the pick-up 1 immediately after the rough search is closer to the inner circumference from the free center position like the position 31b, the safe movable range is small in the inner circumference,
The safe movable range is expanded in the outer peripheral direction.

When the position of the pick-up 1 immediately after the rough search is near the outer periphery from the free center position like the position 31c, the remaining safe movable range in the outer peripheral direction is small,
The safe movable range is expanded in the inner peripheral direction.

In the present embodiment, the maximum number of track jumps possible from the actual position within the slide portion of the pick-up is calculated each time, so the safe movable range in each direction relative to the disk radius is as described above. It can be longer than the method.

Therefore, according to the present embodiment, as described above in the conventional technique, the error caused by the coarse search is about ± 20.
With respect to 0 μm, the probability of reaching the target position safely within the safe movable range and with a precise search by one lens kick increases, so that high-speed search can be realized.

[Third Embodiment] The following description will discuss still another embodiment of the present invention with reference to FIGS. 4, 11 and 12. For convenience of explanation, members having the same functions as those of the members shown in the drawings of the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the structure of the apparatus is the same as that of the first embodiment, but the contents of the high speed search are slightly different. The high-speed search in this embodiment will be described below.

First, several kinds of tables for kick assist are created from the measured data of the drive voltage Vm applied to the feed motor 5, its application time and the amount of slide feed movement, as shown in FIG. . As an example, the kick assist table A is adjusted as much as possible to the movement amount of the pick up proportional to the track jump of the lens kick, and the kick assist table A is adjusted from the movement amount of the pick up proportional to the track jump of the lens kick. Table B has a large amount of assist movement, and the kick amount is proportional to the amount of pick-up movement that is proportional to the lens kick track jump.
A table C having a small amount of assist movement is prepared.

Next, the processing is performed according to the flowchart of the safe movable range search shown in FIG. 1. The movable range of the pick-up obtained by subtracting the uncertainties such as the backlash of the mechanism in advance is set as the safe movable range of the pick-up on the software (S21). 2. A rough search is performed (S22). 3. The position information is read from the information track (S23). 4. It is determined whether the search target has been reached (S24). Normally, the target is not reached in the rough search, so the routine proceeds to S25. 5. The TRP signal is read, and one of the kick assist tables A, B, and C is selected from the actual position in the pick-up slide portion and the direction of the lens kick to be performed next (S25). 6. The allowable number of track jumps within the safe movable range is calculated by the selected kick assist table (S26). 7. The maximum allowable number of track / jumps is compared with the number of track / jumps up to the target, and a search within the maximum allowable number of track / jumps up to the target is executed while assisting kicks in parallel (S27). Next is S23
Return to. 8. When the search target is reached in S24, the TRP signal is read (S28). 9. It is determined whether it is within the safe movable range (S29), and if it is within the safe movable range, the search is completed (S31). 10. If it is in the non-safe movable range in S29, a waiting time is set and slide feeding is performed by the feed servo (S3
0).

The fact that the apparent safe movable range is expanded as a result of doing so will be described with reference to a CD example. In contrast to the standard kick assist table A, in the kick assist table B, the amount of sliding only the slide part for kick assist is set to be about 50 μm larger than the amount of pick-up movement proportional to the lens kick. To do. Further, in the kick assist table C, the amount of sliding only the slide portion by assisting the kick is set to be about 50 μm less than the amount of movement of the pick up proportional to the lens kick. By doing this, the position of pick-up after the rough search is the position 31 from the inner circumference of FIG.
11A and 11B, when a lens kick is to be performed inward from this position in the inner circumferential direction, the kick assist determined by the kick assist table B is accompanied.
It is possible to use a range that exceeds the inner peripheral region 35b of the safe movable range shown by (1) by about 50 μm. That is, in the standard kick assist table A, the lens kick search can be performed even in an area where the safe movable range may be exceeded depending on the target direction of the search, and the search can be speeded up.

In this way, the selected kick assist
Allowable trucks within the safe movable range based on the table
By calculating the number of jumps, the apparent safe movable range is expanded, and one lens kick
Since the search is completed, that is, the probability of reaching the target is increased, the search time can be shortened and a high-speed search can be realized.

[Fourth Embodiment] The following description will explain still another embodiment of the present invention with reference to FIGS. 1 and 13. For convenience of explanation, members having the same functions as those of the members shown in the drawings of the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the structure of the apparatus is the same as that of the first embodiment, but the contents of the high speed search are slightly different. The high-speed search in this embodiment will be described below.

As shown in FIG. 1, in this embodiment, the slide feed servo system has two control signals, that is, a TVD signal and a TRP signal. As described above, the TVD signal is a signal obtained by passing the TRD signal through the low-pass filter 3c and is input to the A / D input terminal c of the control microcomputer 7. The cut-off frequency of the low-pass filter 3c is a signal having a large time constant of about 1 Hz to 10 Hz. Normally, this signal controls the slide feed during disc playback. On the other hand, the TRP signal is a signal obtained by passing the TRD signal through the low-pass filter 6, and the control microcomputer 7
Is input to the A / D input terminal d. The cut-off frequency of the low pass filter 6 is 300Hz to 600H.
It is a signal with a small time constant of about z, and thus can be said to be a signal indicating the actual position of the pick-up.

In the present embodiment, the lens kick search is controlled using the TRP signal as shown in the flowchart of the safe movable range search of FIG. 1. The movable range of the pick-up in which an uncertain factor such as the backlash of the mechanism is subtracted in advance is set as the safe movable range of the pick-up on the software (S41). 2. A rough search is performed (S42). 3. The position information is read from the information track (S43). 4. It is determined whether the search target has been reached (S44). Normally, the target is not reached in the rough search, so the routine proceeds to S45. 5. The TRP signal is read to recognize the actual position of pick up (S45). 6. It is determined whether it is within the safe movable range (S4
6). If OK, the process proceeds to S48. 7. If it is not within the safe movable range in S46, the control microcomputer 7 executes the rapid slide feed (S47). 8. The maximum allowable number of track / jumps is compared with the number of track / jumps up to the target, and a search within the maximum allowable number of track / jumps up to the target is executed while assisting kicks in parallel (S48). Next, the process returns to S43. 9. If the search target is reached in S44, the TRP signal is read (S49). 10. It is determined whether it is within the safe movable range (S50), and if it is within the safe movable range, the search is completed (S52). 11. If it is in the non-safe movable range in S50, the control microcomputer 7 executes the rapid slide feed (S51). Next, the process returns to S43.

As described above, before the lens kick search is performed or after the target position is reached, it is checked whether or not the movable portion 24 is out of the safe movable range. By executing the slide feed, a high-speed search can be realized within the safe movable range.

The disc reproducing apparatus according to the present invention is
You may comprise as follows. That is, the disc reproducing apparatus is equipped with a slide feed motor that feeds the slide portion having the pick-up mounted in the radial direction of the disc, and the amount of movement of the slide portion and In a disc reproducing apparatus that has a means for varying the speed and forms information tracks concentrically or spirally in the radial direction of the disc, means for variably controlling the voltage supplied to the slide feed motor by the software and the application time,・ Means for performing a search by driving the movable part (lens and part of the actuator) within the movable range (search by lens kick), and pick-up just before / after search by lens kick Of the actual position within the movable range of the A sliding feed means is provided which to slide.

According to the above construction, the means for knowing the actual position within the movable range of the pick-up just before and after the search by the lens kick, the supply voltage to the slide feed motor by the software and the application time thereof. By means of variable control and slide feed means that slides in parallel during lens kick operation, to safely move within a movable range of pick-up with a wider movement amount than before, and to provide a waiting time High-speed search can be realized because you can search with unnecessary lens kick.

Further, the disc reproducing apparatus according to the present invention is
You may comprise as follows. That is, in the above-mentioned configuration, the disc reproducing apparatus has means for knowing the actual position within the movable range of the pick-up just before and after the search by the lens kick, and the resulting movable range of the pick-up. Means for calculating the limit of the number of lens kicks possible from the actual position is provided.

According to the above arrangement, the means for calculating the limit of the number of lens kicks possible from the actual position in the movable range of the pick-up makes the actual pick-up in the movable range of the pick-up at that time. The maximum number of track jumps allowed from the position of the lens kick is calculated, and as a result, a lens kick that safely moves within the movable range of the pick-up with a wider movement amount than before and does not require waiting time High-speed search can be realized by searching with.

In addition, the disk reproducing apparatus according to the present invention,
You may comprise as follows. That is, in the above-mentioned configuration, the disc reproducing apparatus has means for knowing the actual position within the movable range of the pick-up just before and after the search by the lens kick, and the resulting movable range of the pick-up. There is provided means for changing the slide feed amount, which is performed in parallel, in multiple stages by software depending on the actual position and the direction of the lens kick to be performed next.

According to the above arrangement, means for knowing the actual position within the movable range of the pick-up just before and after the search by the lens kick, and the actual position within the movable range of the resulting pick-up. From the actual position of the pick-up within the movable range of the pick-up by means of changing the slide feed amount in parallel in multiple stages by software depending on the position and the direction of the next lens kick. The maximum allowable number of track jumps can be further expanded, which allows a safer movement within the movable range of the pick-up with a wider movement amount than before, and a lens kick that does not require waiting time. Search can be performed and high-speed search can be realized.

Further, the disc reproducing apparatus according to the present invention is
You may comprise as follows. That is, in the above-mentioned configuration, the disc reproducing apparatus has means for knowing the actual position within the movable range of the pick-up just before and after the search by the lens kick, and the resulting movable range of the pick-up. There is provided a means for providing a displacement limit from the actual position and the free center, and if the displacement limit is exceeded, a pre-slide feed is provided immediately before the search by the lens kick.

According to the above configuration, the actual position within the movable range of the pick-up and the displacement limit from the free center are set, and if the displacement limit is exceeded, the pre-slide is performed immediately before the search by the lens kick. By means of feeding, it is possible to increase the maximum number of track jumps allowed from the actual position of the pick-up at that time within the range of pick-up. High-speed search can be realized by safely moving with a wider movement amount and performing a lens kick search that does not require waiting time.

[0104]

As described above, in the disk reproducing apparatus according to the first aspect of the present invention, there is provided a slide part on which a pick-up having a movable part is mounted, and a slide feed for sending the slide part in the radial direction of the disk. Slide feeding means to perform,
A lens kick search means for performing a lens kick search for moving the movable part of the pick-up in the slide part in the radial direction of the disc with a predetermined free center position in the slide part as the center of movement; In a disc reproducing apparatus having a safe movable range as the position of the movable part such that the pick-up can normally read information from the disc in the slide part, a known method is known.
The above pick-up for a certain amount of movement of the moving part
The signal that is the signal obtained by removing the predetermined high frequency component from the drive signal of
The movable part represented by using a locking position signal
Calculate the drive sensitivity of the
Position detecting means for detecting a position of the movable portion in the sliding portion to ring-position signal, said position detection
Based on the position information of the movable part detected by the means
And a control means for controlling the slide feeding means so that the movable portion is located within the safe movable range and the slide feeding is performed in the same direction as the lens kick search during the lens kick search. Is provided.

Therefore, there is an effect that a high-speed search can be performed while preventing the deterioration of the performance of reading information from the disc.

According to the disc reproducing apparatus of the second aspect, in addition to the structure of the first aspect, the control means causes the movable portion to fall within the safe movable range based on the position information of the movable portion in the slide portion. In order to do so, the movable maximum value of the movable part is obtained for each of the outer and inner radial directions of the disc, and the above-mentioned value is set so that the movement amount by the lens kick search falls within the maximum value. This is a configuration for controlling the lens kick search means.

Therefore, in addition to the effect of the configuration of claim 1, there is an effect that a higher speed search can be performed while preventing the deterioration of the performance of reading information from the disk.

According to the disc reproducing apparatus of the third aspect, in addition to the configuration of the first aspect, the movable portion is a disc inside the slide portion.
Lens kick on the inner or outer circumference of the disc
・ If you move to the same side in search,
The amount of movement of the slide part can be within the safe movement range above.
When performing a lens kick search so that the moving part fits
The amount of movement is larger than the amount of movement of the movable portion .

Therefore, in addition to the effect of the configuration of claim 1, there is an effect that a higher speed search can be performed while preventing the deterioration of the performance of reading information from the disk.

According to the disc reproducing apparatus of the fourth aspect, in addition to the constitution of any one of the first to third aspects, the control means is such that the movable portion is within the safe movable range before the lens kick search. It is determined whether or not it is, and when it is not, the slide feeding means is controlled so as to slide and feed until the movable portion is located within the safe movable range.

Therefore, in addition to the effect of the structure according to any one of claims 1 to 3, there is an effect that a higher speed search can be performed while preventing deterioration of the performance of reading information from the disk.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a main part in a configuration example of a disc reproducing apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration around a pick-up.

3A and 3B show a state of slide feeding performed in parallel with a lens kick search. FIG. 3A is a tracking error signal, FIG. 3B is a slide feeding speed, and FIG. 3C is a graph showing a voltage applied to the feed motor, FIG. 3D is a PLM signal, and FIG. 3E is a graph showing a TVDO signal.

FIG. 4 is a graph showing the relationship between the amount of slide feed movement, the voltage applied to the feed motor, and the application time.

FIG. 5 is a graph showing an example of a drive voltage waveform applied to a feed motor.

FIG. 6 is a graph showing an example of a drive voltage waveform applied to a feed motor.

FIG. 7 is a graph showing an example of a waveform of a TRP signal used for detecting drive sensitivity.

FIG. 8 is an explanatory diagram showing a state of eccentricity of the disc.

FIG. 9 is a flowchart showing a search process within a safe movable range.

FIG. 10 is a flowchart showing a search process within a safe movable range.

FIG. 11 is an explanatory diagram showing a positional relationship between a pick-up movable portion and its safe movable range.

FIG. 12 is a flowchart showing a search process within a safe movable range.

FIG. 13 is a flowchart showing a search process within a safe movable range.

FIG. 14 is a block diagram showing a schematic configuration of a main part in a configuration example of a conventional disc reproducing apparatus.

FIG. 15 is a diagram showing a state of a rough search by slide feeding using a conventional track counting method. FIG. 15A is a track cross signal, FIG. 15B is a feed motor drive signal, and FIG. c) is a graph showing the speed of slide feeding.

FIG. 16 is a block diagram showing a schematic configuration of a main part in a configuration example of a conventional disc reproducing apparatus.

FIG. 17 is an explanatory diagram showing how cogging torque is generated.

FIG. 18 is an explanatory diagram showing how cogging torque is generated.

[Explanation of symbols]

1 pick up 1a Radial actuator 2 driver amplifier 3 Servo LSI 3a Tracking equalizer amplifier 3b Tracking error waveform shaping amplifier 3c low pass filter 4 motor driver 5 feed motor 6 Low-pass filter (position detection means) 7 Control microcomputer (position detection means, control means) 8 RF amplifier 9 Analog switch (control means) 21 discs 21a Disk center 22 Slide part 23 housing 24 Moving part 25 spring 26 spring 30 perfect circle 31a, 31b, 31c position 35a free center position 35b inner peripheral side area 35c outer peripheral area H eccentricity L1 tracking servo loop L2 slide feed motor servo loop M Free center position PLM play window signal TCRS track cross signal TRD tracking drive signal TRP tracking position signal TVD traverse drive signal TVDO traverse drive output signal Vs slide feed speed Vm Voltage applied to the feed motor

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B 7/085 G11B 21/08

Claims (4)

(57) [Claims] 1. A slide part on which a pick-up having a movable part is mounted, a slide feed means for feeding the slide part in a radial direction of a disk, and a predetermined free center position in the slide part. A lens kick search means for performing a lens kick search for moving the movable part of the pick-up in the radial direction of the disc in the slide part as a center, and the pick-up from the disc in the slide part. In a disc reproducing apparatus having a safe movable range as the position of the movable part that allows normal reading of information, the pick
It is a signal obtained by removing a predetermined high frequency component from the up drive signal.
Which is expressed using the tracking position signal
Obtain the drive sensitivity of the moving part, and use that drive sensitivity to
Position detecting means for detecting the position of the movable portion in the slide portion with respect to a racking position signal , and position information of the movable portion detected by the position detecting means.
Based on the information, the slide feeding means is controlled so that the movable portion is located within the safe movable range and the slide feeding is performed in the same direction as the lens kick search during the lens kick search. A disc reproducing apparatus comprising: a control unit. 2. A radial outer and inner direction of the disk for the control means to keep the movable part within the safe movable range based on the position information of the movable part in the slide part. 3. Regarding the above, the lens kick search means is controlled so that the maximum movable value of the movable part is obtained and the amount of movement by the lens kick search falls within the maximum value. The disc reproducing apparatus described. 3. The movable portion is inside the disc within the slide portion.
Lens kick search on one of the circumference and outer circumference
However, if you move to the same side as that,
As the movement amount of the movable part, the movable part is within the safe movable range.
Of moving parts when a lens kick search is performed
The disc reproducing apparatus according to claim 1 , wherein the amount of movement is larger than the amount of movement . 4. The control means determines whether or not the movable portion is within the safe movable range before the lens kick search, and if not, the movable portion is in the safe movable range. 4. The disc reproducing apparatus according to claim 1, wherein the slide feeding means is controlled so that the slide feeding is performed until it is positioned inside.