DE19655037C2 - Optical memory device with electrical position sensing - Google Patents

Abstract

The optical memory device involves using the information stored on, and reproduced from, an optical memory medium (1), using a light beam generated by an optical unit (40). The light beam is moved in a radial direction, with respect to the disk, by a carriage arrangement (30). The signal path for the reproduced signals contains a filter with a limiting or cut-off frequency. Immediately after the disc is loaded into the machine, a cut-off frequency modification device temporarily sets the filter cut-off frequency to a lower frequency, which is not normally used. A signal is sent from the filter to detect a separation between the disc sectors. A position memory stores the radial positions and the associated frequencies and sector separations. A detector detects the type of optical disc and the current track.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

The present invention relates to a optical storage device, or in particular to a optical storage device in which electrical means for the capabilities of sensors used in the optical storage device cannot be stowed, when the optical storage device is made thinner.

2. Description of the related art

When speaking of existing storage media are a compact cassette for sound recording the magnetic tape is used, a video cassette for recording drawing pictures, and the like are known. However, are Data recorded on any of these media, not freely accessible. Also are the recorded Data analog information. That is why such after agree that reproduced data may contain noise nen that the data can be degraded if they copied so that the data can be degraded, if they are stored for a longer period of time, and like that.

As for another type of storage medium, is an optical disk put for practical use which makes it possible to put a digital signal in which data has been converted in a data track a disk and using the signal of returned light from a laser beam that hits the Data track was irradiated to read. Examples for Typical of the optical disk is a compact disk (CD) for recording music, a laser disc (LD) for Recording images and the like. Further strides the development of a digital video disc (DVD) is advancing that designed to be compact for recording images. There these types of optical disks, on the other hand, have large storage capacities have storage capacity, they are used as data storage media the names CD-ROM, LD-ROM and the like have been used.

In recent years there has also been a magneto-opti cal plate has been used in practice that made it possible light, using data on a recording medium of a laser beam and magnetism and the Read data using the laser beam. This one Type of magneto-optical disk has a large storage capacity it is used as an optical storage device in the Form of external storage used for a computer.

As previously mentioned, storage media include below Using light an optical disk and a magneto- optical disk. A description is given under the Assumption that the storage media that use light are im generally considered to be optical disks.

The optical disk used for optical storage chervorrichtung is used, arrives as a storage medium into the limelight that is in the multimedia systems that are in out over the last few years is a key point lung, and is usually in a cassette ver jams to ensure portability. The cassette with optical disk is placed in an optical disk unit the. Information is then processed using an opti written on the optical disk or by you read.

At present, the optical disk unit is often used externally, via a SCSI interface with a computer connected, used.

Recently there has been a desire to have a optical disk unit in a portable personal computer to assemble. Technological development makes an effort quick steps, a more compact and lightweight one Realize construction. Take one for example Floppy disk unit and a hard disk unit that is included in the Past as external storage for a personal computer ter have been used, the trend has been towards one so much more compact construction that a Dis chain unit or a hard disk unit into a gap in a main unit of a personal computer which is about 17 mm thick.

To insert the optical disk unit, the that is, an optical storage device, into the gap with a thickness of about 17 mm, that of a floppy disk unit or hard disk unit is constructed, the exist rend optical disk unit can be made thinner.

However, when the optical disk unit is thinner so that it is inserted into the approximately 17 mm thick gap that can be set for a floppy disk unit or hard disk unit is constructed and attached to a personal computer is formed, however, because there is a space within the optical disk unit is vertically limited, a conventional Licher position sensor and a sensor for detecting the Position of an objective lens can be made smaller. Because the size of the position sensor and the sensor for detection The position of an objective lens makes it difficult to find one Carriage on which an optical head is mounted, inside of the optical disk unit.

From US 4926405 A is an optical memory known device with a carriage or glider, however not gently but accelerated at a constant rate becomes.

The object of the present invention is to provide a to provide optical storage devices which, even then, when it is made thinner and a position sensor must dispense with an actuator for an objective lens that mounted on a trolley, in the middle of the trolley can position.

This object is achieved by the features of claim 1 solved.

According to the present invention, if a Search operation of a car for an optical storage medium is started, the car accelerates gently, slowed down gently and thus positioned on a target track become. The vibration of a lens actuator on the cart that occurs during the search is minimized and the Lens actuator is essentially in the middle of the carriage locked.

According to this aspect, even if the optical Disk unit is made thinner and a conventional one Lens position sensor must be dispensed with, an objective lens of the Lens actuator that is mounted on the carriage while looking to be positioned in the middle of the carriage by a drive speed is controlled with which a Voice coil motor (VCM) drives the carriage.

In an optical storage device according to the fourth th aspect of the present invention to meet the third object of the present invention is achieved during a search operation of a car with respect to an optical Storage medium a false lens signal that a lens signal that is used to make a lens to lock the actuator in the middle of the carriage on the Base of the envelope of a tracking error signal generated by reflected light from a light beam obtained from the optical storage medium. The wrong lens signal is used to control the lens tiger in the middle of the cart.

According to the fourth aspect, even if an opti cal plate unit is made thinner and a conventional Chen lens position sensor must be dispensed with, since a Linsenbetä Tiger is supported on a cart by a spring Tracking error signal (TES) are generated as a signal, one component of a lens position sensor output contains. A fake lens lock signal that Lens lock signal is equivalent, can therefore under Using the tracking error signal can be generated. Therefore, an objective lens of the lens actuator based on the cart is mounted while looking in the middle of the Be locked.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention becomes from the following Description with reference to the accompanying drawings gen better understood, in which:

Fig. 1A is an oblique view showing a conventional optical disk unit from above;

Fig. 1B is an oblique view showing the conventional optical disk unit from below;

Fig. 1C is a view for explaining an example of the structure of a conventional optical head;

Fig. 2A is an oblique view of the exterior of the front of an optical storage device of the present invention;

Figure 2B is an oblique view of the exterior of the back of the optical storage device of the present invention;

Fig. 3 is an exploded perspective view of the front of the optical storage device of the present invention;

Fig. 4 is an exploded perspective view of the rear of the optical storage device of the present invention;

Fig. 5 is an explanatory diagram showing the structure of an optical disk;

Fig. 6 is a basic configuration diagram of an optical disk unit;

Fig. 7 is a block circuit diagram showing the configuration of a read LSI circuit in a signal processing unit shown in Fig. 6 in the first embodiment of the present invention;

Fig. 8 is a characteristic graph for explaining the change in cut frequency of a filter shown in Fig. 7 according to the present invention;

Fig. 9A shows waves of signals obtained when the cutting frequency is set high, wherein ( 1 ) shows a wave of an ID signal, ( 2 ) shows a wave of a primary differential signal, and (3 ) shows a wave of a sector mark signal;

Fig. 9B shows waves of signals obtained when the cut frequency is set to low, wherein ( 1 ) shows a wave of an ID signal, ( 2 ) shows a wave of a primary differential signal, and (3 ) shows a wave of a sector mark signal;

Figures 10A and 10B are flow charts showing a Detekti the position show onssteuerprozedur with respect to a track in the first embodiment of the present invention.

Fig. 11 is a timing chart illustrating the operation described in Fig. 10;

Fig. 12 is a schematic view of a main portion of the front of an optical storage device of the second embodiment of the present invention;

Fig. 13 is a schematic view of a main portion of the rear side of the optical storage device of the second embodiment of the present invention;

. 14A is an enlarged plan view of the top of a lens carriage;

Fig. 14B is an enlarged plan view of the side of the lens carriage;

Fig. 14C is an enlarged plan view of the section through the lens carriage;

Fig. 15A is a diagram showing the relationship between the laser output setting range of an optical disk medium and the position of a photosensor for the purpose of explaining the laser output setting range for a laser diode;

Fig. 15B is a waveform diagram showing an output signal of the photosensor shown in Fig. 15A;

. 16A and 16B are flowcharts Fig describing an example of the current control for a VCM;

Fig. 17 is a flow chart showing an example of the current control for the VCM;

Fig. 18 is a waveform diagram relating to an example of the current control for the VCM which is executed when an output of a position sensor is high, and which shows a current in the VCM and a waveform of a photosensor signal;

Fig. 19A is a waveform diagram relating to an example of the current control for the VCM, which is executed when the output of the position sensor is low, and shows the current in the VCM and the wave of the photosensor signal;

Fig. 19B is a waveform diagram relating to an example of the current control for the VCM which is executed when a car hits an external stop, and which shows the current in the VCM and the wave of the photo sensor signal;

Fig. 20 is an enlarged oblique view of a lens actuator in an optical storage device of the third embodiment of the present invention;

Fig. 21A is a characteristic graph showing a target profile representing the acceleration of the VCM;

Fig. 21B is a characteristic graph showing a target profile representing the speed of the VCM;

Fig. 21C is a characteristic graph showing a target profile representing the position of the VCM;

Fig. 22A is a schematic configuration diagram showing the configuration of an optical storage device of the fourth embodiment of the present invention;

Fig. 22B is a schematic configuration diagram showing the configuration of a conventional optical storage device;

Fig. 23A is a waveform diagram of a conventional tracking error signal generated during search;

Fig. 23B is a waveform diagram showing the speed characteristic of a conventional VCM;

Fig. 23C is a waveform diagram showing a conventional lens position signal;

FIG. 23D is a waveform diagram showing a Spurver folgungsfehlersignal produced according to the present invention during the search;

Fig. 23E is a waveform diagram showing a lens position signal required by a lens operator;

Fig. 23F is a waveform diagram showing a false lens signal generated from the tracking error signal shown in Fig. 23D; and

Fig. 23G shows a waveform of a current flowing in the lens actuator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before describing the preferred embodiments, an explanation will be given of the conventional optical disk unit shown in Figs. 1A to 1C.

Fig. 1A is an oblique view showing an optical disk unit, which is a conventional optical storage device from above, in which the optical disk unit is shown without its top cover and circuit board. Fig. 1B is an oblique view showing the conventional optical disk unit from below without its lower cover. Referring to Figures 1A and 1B, there are shown a base 201 , a carriage 202 , a stationary optical unit 203 , a lens actuator 204 , magnetic circuits 205 , a spindle motor 206 , an eject motor 207 , a switch 208 , rails 211, and a light emitting diode (LED ) 215 . Main components of an optical disk are mounted on the base 201. On the carriage 202 , the lens actuator 204 for moving an objective lens constituting a movable optical unit and a mirror (not shown) for deviating an optical path are mounted, and it moves along the rails 211 . The stationary optical unit 203 is composed of a laser diode, a half mirror, a light receiving device and the like, sends a light beam to the movable optical unit, and receives reflected light coming from the movable optical unit to reproduce data and servo control information.

The magnetic circuits 205 constitute voice coil motors for moving the carriage 202 along the rails 211 . The spindle motor 206 rotates an inserted optical disk medium. The eject motor 207 is incorporated in a mechanism for ejecting the optical disk medium. The switch 208 operates the eject motor 207 .

Fig. 1C is a view for explaining an example of the structure of an optical head for a conventional optical disk unit.

On the carriage 202 , as mentioned above, the lens actuator 204 for moving the objective lens 209 and a mirror 210 for changing an optical path are mounted, it constitutes the movable optical unit and moves due to the effects exerted by currents, which flow through coils mounted in holders 214 and through magnetic fields formed by magnetic circuits 205 along rails 211 .

The stationary optical unit 203 projects a light beam originating from the laser diode 212 onto the mirror 210 to modify the optical path, and thus projects the light beam onto the objective lens 209 . The objective lens 209 is aligned with a track specified by a higher level unit of the optical disk medium 213 as a result of the operations of the carriage 202 and the lens actuator 204. The objective lens 209 is focused on the track with which it is aligned, thereby enabling data writing. Further, light reflected from the optical disk medium 213 along a path opposite to the optical path is received by the objective lens 209 and the mirror 210 . Then data and servo control information are reproduced.

The objective lens 209 is positioned near a specified track of the optical disk medium 213 by the carriage 202 running along the rails 211 as mentioned above. The optical disk medium 213 and the rails 211 must be strictly parallel to each other to the extent of parallelism ensured by the focus servo. As shown in FIG. 1B, the LED 215 is mounted on the rear of the carriage 202. A position sensor is arranged in a zone opposite the LED 215 and detects the position of the carriage 202 . A signal sent from the position sensor is used to position the carriage 202 on a specified track of the optical disk medium 213.

However, when an optical disk unit is made thinner so that it is inserted into a gap approximately 17 mm thick that can be used for a floppy disk unit or hard drives unit is constructed and gebil on a personal computer det is, a conventional position sensor or a Sensor for detecting the position of an objective lens stay away because the space in the optical disk unit is limited vertically. This poses the problem that it will be difficult to position the car.

Below are embodiments of an optical memory cher device of the present invention described. To It starts with the mechanical structure of an optical memory described device that has been made thinner and to which the present invention is applied.

Fig. 2A is an oblique view of the exterior of the front side of a thinner optical disk unit of 3.5 inches of the present invention. Fig. 2B is an oblique view of the exterior of the rear of the optical disk unit shown in Fig. 2A. A front frame 10 b has a door 10 which is held closed by a spring which is not shown. The door 10 b opens when inserting or ejecting a cassette with an optical disk.

The front frame 10 has an eject button 10 a and a hole for manual ejection 10 d. The eject button 10 a is used to instruct the ejection of an optical disk cartridge and the automatic ejecting auszufüh Ren. The manual ejection hole 10 d is used in the event of a power failure, inspection or failure to remove an optical disk cartridge to solve a unit by inserting a pin or the like into it. Furthermore, the front frame 10 has an LED 10 c, which lights up to indicate an operating state of the unit.

A drive base 20 on which the front frame 10 is mounted is covered with a circuit board 11 to which various ICs and a flexible circuit board are connected, a frame 12 for defining the boundary of the optical disk unit, and a cover 13 . The circuit board 11 is attached to the drive base 20 . The cover 13 is attached by inserting screws 14 a, 14 c, 14 f and 14 h in holes formed in rubber vibration isolators 14 b, 14 d, 14 e and 14 g, and in holes in the drive base 20 and the frame 12 are gebil det. A switch, which is gekop pelt with the eject button 10 a, is mounted on the circuit board 11.

The optical disk unit has with the cover 13 and the circuit board 11 , which are placed on the drive base 20 , a height H of about 17 mm. The height h of the front frame 10 with the door 10 d has a relationship of H ≦ h with respect to the total height H.

Fig. 3 is an exploded view of the optical disk unit shown in Figs. 2A and 2B.

FIG. 4 is an exploded view showing the rear of the optical disk unit of FIG .

Referring to Fig. 3, the optical Plat teneinheit generally comprises seven main parts: a circuit board 11 , a cassette holder 71 with an opening 71 a, a drive base 20 , a lens carriage 30 with an objective lens L, a slide plate 24 , a turntable 22 and a cover 13 arranged in this order.

A power connector and an interface connector are attached to the circuit board 11 . Circuit elements such as a digital signal processor (DSP) for controlling reproduction, recording and erasure of information relating to an optical disk, an MPU and the like are mounted on one side of the circuit board 11 . The cassette holder 71 is arranged under the circuit board 11 . The circuit board 11 with parts mounted on it is connected to the drive base 20 by screws in a plurality of holes 11 a through a large number of mounting sections 71 of the cassette holder 71 is set. Numeral 201 denotes a room.

The drive base 20 has openings 20 a to 20 f which are used to assemble given parts. A stationary optical unit 40 ( not shown in Fig. 3) consisting of optical parts for directing a light beam to a surface of an optical disk or for directing light reflected from an optical disk to a photodetector is gebil det as a united body on the drive base 20 by die-casting of aluminum. A cover 40 a is arranged on the stationary optical unit 40 as a dust protection means.

The lens carriage 30 for holding a lens and for moving those in a radial direction of an optical disk is molded as a unitary body using a thermally fusible resin or the like, with coils in coil sections 32 a and 32 b at both edges of the lens carriage 30 embedded are. A magnet is attached to the rear of each of the upper yokes of the lens carriage 30. Lower yokes of him are inserted into central openings of the coil sections 32 a and 32 b. In this state, the coil sections 32 a and 32 b are movable with respect to the lower yokes. The ends of the upper and lower yokes are connected by screws, whereby magnetic circuits 33 a and 33 b are realized.

A turntable unit 222 is mounted on a plate 21 on it. Slide pins 23 a and 23 b are attached to the right and left sides of the plate 21 . The turntable 22 with a diameter of 21 mm protrudes through the opening 20 a of the drive base 20 to the cassette holder 71 . When an optical disk cartridge is inserted into the cartridge holder 71 , the hub of the optical disk is attracted by a magnetic body attached to the front of the turntable 22 and thus held. The turntable 22 is connected to a spindle motor for rotating the turntable at a given rotational speed.

An eject motor 50 used to eject an optical disk cartridge is stowed in an eject motor loading section 55 of the drive base 20. The ejection motor 50 is connected to the drive base 20 by tightening screws, which are not shown and which are inserted through screw holes 50 a and screw holes 55 a.

The slide plate 24 , which slides in a front and rear direction of the unit by the eject motor 50 when an optical disk cartridge is to be ejected, is disposed above the plate 21 with the turntable 22 . When the plate 21 is raised by sliding along the slide pins 23 a and 23 b of the plate 21 along the guides 85 of the slide plate 24 , the turntable 22 rises through the opening 20 a. The turntable 22 is then released from the optical disk hub, thereby unloading the optical disk cartridge.

After the above parts are installed on the drive base 20 , the frame 12 is mounted on the drive base 20 so that the frame 12 can cover the outer periphery of the drive base 20. The cover, which is formed by pressing a ferromagnetic material, such as. Stainless steel, is then screwed to the opposite side of the drive base 20 with respect to the cassette holder 71.

Fig. 5 shows the structure of an optical disk medium 1 , which is to be inserted into a main body of the optical disk unit through the door 10 b of the front frame 10 , which was described in connection with FIG. 2. The optical disk medium 1 is concentrically divided into a plurality of zones from its inner periphery to its outer periphery. In the embodiment, the innermost peripheral part is zone 0 and the outermost peripheral part is zone 9 . Each zone contains a multitude of tracks. Each track has an ID division 2 , which only reflects a light beam coming from the aforementioned laser diode (also called an embossed division or preformatted division), and an MO recording division 3 , which is used to pass data through record or reproduce a beam of light (also known as data splitting). The ID division 2 is shown in Fig. 5 with a short black line. When enlarged, the ID division 2 looks like a set of numerous embossed grooves called dimples. A sector mark, a track signal, a section signal, a CRC signal and the like are written in the ID division. A zone number, track number and the like designating a zone, track and the like from which data is smoothly reproduced can be detected by reproducing a signal read from the ID division 2. The MO recording pitch 3 is an area located between ID pitches 2 and used to record data.

Sections of the optical disk medium 1 having the above structure have substantially the same length. As long as the rotating speed of the optical disk medium 1 is constant, the cycle of ID division in an outermost zone is the fastest.

Fig. 6 is a block configuration diagram showing the basic configuration of the optical disk unit 4 including the aforementioned components. In the optical disk unit 4 , a microprocessor unit (MPU) 42 sends or receives commands or data through an interface 43 to or from a host computer. A read-only memory (ROM) 38 in which data is stored on the optical disk medium 1 is connected to the MPU 42 . The rotation of a spindle motor (SPM) 45 for rotating the optical disk medium 1 is controlled by an SPM control unit 36 . Further, an optical pickup 37 for reproducing data can be moved in a radial direction of the optical disk medium 1 by a motor 49 controlled by a coarse motor control unit 48. The optical pickup 37 irradiates laser light on a data side of the optical disk medium 1 and receives reflected light.

The optical pickup 37 includes a laser diode for irradiating laser light, and, gene a motor which is used to a track of the optical disc medium 1 to verfol. The focus of the laser diode or the tracking is controlled by a Aufnehmersteuereinheit 47th Data reproduced by the optical pickup 37 are processed by a signal processing unit 41 .

The pick -up control unit 47 , the SPM control unit 36 and the coarse motor control unit 48 are controlled by a plate controller 9 . Signals are sent or received between the disk controller 9 and the signal processing unit 41. The disk controller 39 sends or receives a command or data to or from the MPU 42 in synchronization with a clock.

Thus, the optical disk unit 4 rotates the optical disk medium 1 at a certain speed using the SPM 45 , moves the optical pickup 37 in the radial direction of the optical disk medium 1 , performs focusing or tracking, and thus reproduces data. Indeed, as described above, the optical pickup 37 comprises a stationary optical unit for generating a light beam using a laser diode, and a carriage for projecting the light beam onto a mirror to modify the optical path and thus projecting the light beam onto the optical disk medium 1 via an objective lens. The objective lens on the carriage is aligned and focused on the track due to the operation of the Linsenbetäti gers with a track specified by a higher level unit of the optical disk unit 1. Thus, the optical pickup 37 writes data on the optical disk medium 1 . The optical pickup 37 receives light reflected from the optical disk medium 1 via the objective lens and the mirror along a path opposite to the above optical path. The signal processing unit 41 then reproduces data and servo control information. The motor 49 is implemented with voice coil motors for moving the carriage along rails.

The optical disk unit 4 to which the present invention is applied is thin about 17 mm in thickness. A position sensor and a sensor for detecting the position of an objective lens are not included. The car can therefore not be positioned without taking appropriate action. Thereafter, when the power is turned on, the optical disk unit 4 can not write or read the optical disk medium 1 if it is uncertain on which track of the optical disk medium 1 the optical pickup 37 (carriage) is positioned.

In an optical storage device according to the first aspect of the present invention, the position of a carriage can be detected using a signal read from the optical disk medium 1 even if it is made thinner and a position sensor and a sensor for detecting the position of an object tivlinse must do without. The components involved are described below.

FIG. 7 shows the configuration of a read LSI circuit 160 incorporated in the signal processing unit 41 shown in FIG. The read LSI circuit 160 includes two automatic gain control (AGC) circuits 161 and 162 , a multiplexer (MUX) 163 , a filter 164 , a sector mark detection circuit 165 , a logic IC 166 , a synthesizer 167 and a phase locked loop ( PLL) 168 .

The AGC circuit 161 controls the gain of an ID signal including a sector mark signal and inputs it to the MUX 163 . The AGC circuit 162 controls the amplification of an MO signal and inputs it to the MUX 163 . The MUX 163 processes a signal sent from an internal ID signal processor or MO signal processor according to an ID / MO switching signal sent from the MPU, and sends a resultant signal to the filter 164 . The filter 164 includes an equalizer 641 and two differential circuits 642 and 643 . A signal input to the filter 164 is primarily differentiated by the differential circuit 642 after passing through the equalizer 641. A resulting primary differential signal is branched into three sections, which are input to the differential circuit 643 , the sector mark detection circuit 165, and the PLL 168. The primary differential signal input to the differential circuit 643 is further differentiated into a secondary differential signal and then input to the sector mark detection circuit 165. The sector mark detection circuit 165 detects sector mark pulses in the inputted primary differential signal and secondary differential signal. The sector mark pulses are sent to the logic IC 166 . An output of the logic IC 166 is input to the synthesizer 167. A signal sent from the MPU is also input to the synthesizer 167. A synthetic signal provided by the synthesizer 167 is then input to a voltage controlled oscillator (VCO) in the PLL 168. The PLL uses the primary differential signal and the signal sent from the synthesizer 167 to generate read data and a read clock.

A cut frequency change signal is input from an external MPU to the filter 164 in the reading LSI 160 having the above components. The filter 164 is a low-pass filter in which, as shown in Fig. 8, a normal cut frequency FC1 and a cut frequency FC2 used to identify a zone are set. The cut frequency FC1 is, for example, 15.4 MHz, while the cut frequency FC2 is such a low frequency that it is not normally used for reproducing an MO signal, and is, for example, 2 MHz.

Fig. 9A shows signals obtained when the cut frequency set in the filter 164 shown in Fig. 7 is the high frequency FC1, where ( 1 ) shows an ID signal, ( 2 ) shows a primary differential signal and ( 3 ) shows a sector mark signal (sector mark pulse). Fig. 9B shows signals obtained when the cut frequency of the filter 164 is the low frequency FC2, where ( 1 ) shows an ID signal, ( 2 ) shows a primary differential signal, and ( 3 ) shows a sector mark signal (sector mark pulse) . In the ID signals shown at (1 ) in FIGS. 9A and 9B, a component having a large amplitude is a sector mark signal read from the ID division 2 in FIG. A component having a small amplitude is a signal read from the MO recording division 3 shown in FIG. As can be seen from the comparison between Figs. 9A and 9B, the sector mark signal contains noise and sector mark pulses when the cutting frequency is high (FC1). Much noise is contained even in the signal read from the MO recording division 3. In contrast, when the cutting frequency is low (FC2), no signal other than sector mark pulses is included in the sector mark signal. Therefore, once the cut frequency is decreased, a position on the optical disk medium 1 can be predicted by measuring the cycle of the sector mark signal.

In the optical storage device according to the first aspect of the present invention, as mentioned above, the cut frequency of the filter 164 is decreased immediately after the power is turned on. This makes it easier to detect sector mark pulses of a sector mark signal. The cycle of the detected sector pulses is detected, whereby the storage capacity of the optical disk medium 1 from which data is fluently reproduced by a carriage and from a track number concerned is detected.

A procedure of the above detection will be described in conjunction with the flowcharts of Figs. 10A and 10B.

A routine described in Figs. 10A and 10B is activated when the optical disk medium 1 is set in a main body of the optical disk unit 4 . When the optical disk medium 1 is set, first at step 1001, the optical disk medium 1 is driven. At step 1002 , tracking adjustment is carried out so that a laser beam can be irradiated on a track of the optical disk medium 1. In step 1003 , control is made to decrease the cut frequency of the filter 164 by changing the cut frequency from the FC1 value to the FC2 value.

After the cutting frequency is decreased, separation of sectors is measured at step 1004 by detecting the cycle of a sector mark signal of an inputted ID signal. After the sector separation is measured, a sector separation table is consulted at step 1005. A sector separation table is created in association with a storage capacity of, for example, 128 Mbytes or 230 Mbytes. The table is consulted to see which table contains a value that corresponds to a measured sector separation. Table 1 below is the table stored in the optical disk medium 1 having a storage capacity of 128 Mbytes, with zones, standard times coinciding with a sector, minimum times coinciding with a sector, and maximum times coinciding with a sector Coincide sector, are stored.

Table 1 Cycles of zones representing 128 Mbytes

At step 1006 , it is judged according to the table whether or not the optical disk medium can contain 1128 Mbytes. For example, if the inserted optical disk medium 1 can contain 230 Mbytes, control goes to step 1007 . If the optical disk medium is 128 Mbytes, control transfers to step 1017 . The processing of step 1017 to be performed when the optical disk medium is 1128 Mbytes is the same as that described below, to be performed when the optical disk medium can be 1230 Mbytes. The processing to be carried out when the optical disk medium can contain 1230 Mbytes will be described as a typical example.

At step 1007 , the cutting frequency is reset to the original value, that is, the cutting frequency is changed from the value FC2 to the value FC1. In this state, a reproduction frequency F assigned to a zone derived from a sector separation measurement at step 1004 is set at step 1008. At step 1009 , a reproduced signal reproduced at the frequency F is read. At step 1010 , it is judged whether or not an ID can be recognized at the frequency F. If an ID cannot be recognized, control goes to step 1011 . The frequency of increasing or decreasing the frequency F is calculated. At step 1012 , it is judged whether or not the number of times of increasing or decreasing the frequency F is equal to a given number. If the number of times the frequency F is increased or decreased does not reach the given number, control goes to step 1013 . The frequency F is increased or decreased, and then control returns to step 1009 . The number of times the frequency F is increased or decreased is determined according to a range from a maximum frequency assigned to each zone in the table above to a minimum frequency assigned to it and a value by which the frequency F is increased or is reduced.

If, at step 1010, an ID cannot be recognized by a given number of raising or lowering the frequency F, it is determined that the storage capacity of the optical disk medium 1 judged at step 1006 is incorrect. Control then transfers from step 1012 to step 1017 . The processing that is required when the storage capacity is 128 Mbytes is carried out.

In contrast, if an ID can be recognized by increasing or decreasing the frequency F at step 1010 , control goes to step 1014 . A current lane position is identified based on the recognized ID information. In this embodiment, the current track position is determined by the identification of step 1014 not finally but tentatively. At step 1015 , the carriage is moved to a control zone of the optical disk medium 1 according to the tentatively determined track. A signal written in the control zone is recognized. At step 1016 , a track on which reproduction is in progress is finally determined.

FIG. 11 is a timing chart showing the above control, wherein (a) shows an ID signal, (f) shows a sector pulse signal, and (g) shows the operation of the logic IC 166 of FIG . A rectangular part of (a) is an envelope of an ID signal shown in Fig. 9B ( 1 ) which has been read from an ID division. (f) shows sector mark pulses of a sector mark signal shown in Fig. 9B ( 3 ). The logic IC 166 drives a gate signal high with the first sector mark pulse of the sector mark signal and holds the gate signal high while counting down a predetermined count value CV. While the gate signal remains high, the logic IC 166 ignores any rising edge of the sector mark signal. Thereafter, the logic IC 166 drives the gate signal high with the first pulse after an undefined duration U of the sector mark signal expires, and holds the gate signal high while a predetermined count is counted down.

A control program to be carried out by the logic IC 166 measures the cycle of sector mark pulses by measuring the interval between rising edges of the gate signal, and then determines a zone number of a zone of the optical disc medium 1 in which the reproduction is in Is in progress.

Next, an optical storage device of FIG second embodiment of the present invention ben.

Fig. 12 is a schematic view of the main portion of the front of the optical disk unit described in connection with Figs. 2A to 4, in which the circuit board 11 , the frame 12 and the cover 13 are removed. FIG. 13 is a schematic view of the main portion of the rear of the optical disk unit shown in FIG. 12.

On the lens carriage 30 , a lens actuator 60 having an objective lens L and magnetic circuits for driving the lens are mounted. A flexible printed circuit sheet 39 a for inputting signals containing a signal that is used to drive the lens actuator 60 in a focus direction or tracking direction is attached along the coil section 32 a of the lens carriage 30 using an adhesive. Furthermore, a carriage cover 115 made of a ferromagnetic material, such as. B. stainless steel, arranged so that it can surround the objective lens L. Voice coil motors (VCM) are arranged on both edges of the lens carriage 30 for moving the lens carriage 30 in the radial direction of an optical disk. The VCM's include the coil sections 32 a and 32 b of the lens carriage 30 and the magnetic circuits 33 a and 33 b, each containing yokes and magnet.

Guide rails 113 a and 113 b to facilitate the movement of the lens carriage 30 loading are attached, they are held by leaf springs 112 a, 112 b and 114 under pressure. In other words, the leaf springs 112 a and 112 b work as fastening sides for fastening the guide rail 113 b by urging the guide rail 113 to abut against the walls of the drive base 20 opposite to both ends of the guide rail 113 b. The Blattfe 114 pushes the guide rail 113 a towards the guide rail 113 b. The guide rails 113 a and 113 b are in engagement with bearings 31 a to 31 c, which sections of the lens carriage 30 are arranged at the limits of the coil.

Incidentally, the state of the lens carriage 30 shown in Figs. 12 and 13 is a locked state. This can be seen from the fact that a carriage lock 26 abuts the lens carriage 30. The carriage lock 26 prevents the lens carriage 30 from leaving an initial position in the radial direction of an optical disk.

A projection 22 a is arranged in the center of the turntable unit 222 , which protrudes through the opening 20 a of the drive base 20 , and is inserted into a central hole in the hub of an optical disk. A flexible printing circuit sheet (FPC) 89 is attached to the board 21 using an adhesive. A sensor 86 for detecting write enable set on an optical disk cartridge, a sensor 87 for detecting write protection set on an optical disk cartridge, and a cartridge insertion sensor 88 for detecting insertion of an optical disk cartridge mounted on the FPC 89.

Incidentally, a 3.5-inch magneto-optical disk cartridge with a storage capacity of 128 MB corresponds to ISO / IEC standard 10090, while the one with a storage capacity of 230 MB corresponds to ISO / IEC standard 13963. These types of disk cartridges are already on the market. An optical disk cartridge is therefore not specifically shown. Furthermore, one end of the FPC 89 is connected to a connector mounted on the FPC 39 for transmitting a signal used to control the movements of the lens carriage 30 and the lens actuator 60 . The FPC 39 is laid along a transverse side of the drive base 20 and bent to be connected to a connector which is arranged on a circuit board.

A slide plate 24 is disposed under the plate 21 , that is, between the drive base 20 and the plate 21 . When the slide plate 24 moves in a forward and backward movement Y of the unit, the relati ven positions of dowel pins 29 a to 29 c, which are arranged on the drive base 20 , with respect to a plurality of grooves 24 a to 24 change c formed on the slide plate 24 . The slide plate 24 moves backward upon an eject instruction, whereby an optical disk cartridge is detached from the optical disk unit. Thereafter, the sliding plate 24 is due to the elastic force exerted by coil springs 28 a and 28 b, one end of which is connected to the sliding plate 24 and the other end of which is connected to the mounting pins 29 a and 29 b, moved forward in the optical disk unit and thus quickly returned to the original position.

The ejection instruction can be given by depressing an eject button 10 a, which is arranged on a front frame 10 , or by vigorously inserting a pin or the like into a hole for manual ejection 10 d. In the first case, if the eject button 10 a is never pressed, an eject motor 50 is driven. When an edge 24 d of the slide plate 24 is pulled, the slide plate 24 moves rearward in the optical disk unit. In the latter case, when a pin or the like is forcefully inserted into the manual ejection hole 10 d, the pin abuts against an upright wall 10 f of the slide plate 24 . This causes the slide plate 24 to move rearward in the optical disk unit.

A leaf spring 111 is attached to a stationary optical unit 40 which is attached to the rear of the drive base 20 . The leaf spring 111 presses an M-lens 46 and an S-lens 47 against surrounding walls of the drive base 20 and so fastened them. A photodetector 52 and a photodetector 53 are stowed in loading sections of the drive base 20. The photodetector 52 detects a reproduced data signal sent from an optical disk using returned light passed through the lens carriage 30 serving as a movable optical unit. The photo detector 53 detects a focus servo control signal and tracking servo control signal.

Reference numerals 23 a and 23 b denote slide pins of the plate 21 . 91 denotes an FPC. 91c and 91d denote screw holes. 92 denotes a connector.

FIG. 14A is an enlarged plan view showing senwagen the Lin 30 from above. FIG. 14B is an enlarged side view. Fig. 14C is an enlarged sectional view. Referring to Figs. 14A to 14C, bearings 31 a to 31 c, coil sections 32 a and 32 b, an FPC 39 a, an Actuate gerbasis 61 , screw fasteners 61 a and 61 b, yokes 61 c, 61 d and 63 , a Focus coil 65 , tracking coils 66 a and 66 b, wires 67 a and 68 a, connection plates 67 b, 67 c, 67 d and 69 d, reference trenches 121 a to 121 c, a coil spring 122 a, a screw 122 b, a condenser lens 129 , for receiving or projecting a light beam from or onto the stationary optical unit 40 , a driver 152 , a lens holder 621 , a wire holder 622 and an objective lens L are shown. An arrow A shows a preload.

In the lens carriage 30 having the above components, in this embodiment, an intercepting projection 35 , which extends in a direction parallel to a direction of movement of the carriage 30 , is arranged at an edge of the carriage 30 , which is driven by a spindle motor for rotating a optical disk media is removed. The scavenging Before crack 35 is shown in Fig. 12 and 13.

Furthermore, in this embodiment, a photosensor 7 , which comprises a light emitting device 5 and a light emitting device 6 , is arranged across a movement path which the intercepting projection 35 follows with the movement of the carriage 30. The photosensor 7 is arranged at a position where light incident on the photosensor 7 is intercepted by the intercepting projection 35 only during a period during which the carriage 30 is disposed in a laser output setting range that is in the vicinity of the outer Perimeter of the optical disk medium 1 is defined. In the optical disk unit according to the second aspect, therefore, it is detected whether or not light incident on the photo sensor 7 is intercepted by the intercepting projection 35 . Thus, it is detected whether or not the carriage 30 has moved to the laser output setting area defined on the optical disk medium 1. The laser output setting area is used to set the laser output or the intensity of a laser beam to be irradiated on the optical disk medium 1 , and is normally defined on the outer periphery of the optical disk medium 1 so that data zones of the optical disk medium 1 are not adversely affected.

An amount of light of a laser beam coming from the stationary optical unit 40 in the optical disk unit is set to a certain level. When the amount of light does not reach the level, the optical disk unit does not work. Therefore, it is necessary that the optical disk unit detect an amount of light of a laser beam when the power is turned on. If a laser beam is checked in a data zone of the optical disk medium 1 to detect the amount of light of the laser beam, data erasure must be feared. Detection of an amount of light of a laser beam is therefore carried out when the carriage 30 is disposed in the laser output setting area defined on the outermost periphery of the optical disk medium 1. The carriage 30, therefore, must be displaced to be in the Laserausgabeeinstellbereich defined on the outer most circumference of the optical disc medium 1 immediately after the power supply of the optical discs is switched medium. 1

FIG. 15A and 15B are diagrams for explaining the La serausgabeeinstellbereichs for a laser diode. Fig. 15A shows the relationship between the laser output setting range on an optical disk medium and the position of a photosensor. Fig. 15B shows an output of the photosensor.

Referring to Fig. 15A, an optical disk medium 1 is shown. The left side of the drawing is an outer peripheral side, while the right side of it is an inner peripheral side. A given area on the outermost circumference side of the optical disc medium 1, to the output of a laser diode whose light is irradiated by the carriage 30 on the optical disc medium 1 set a Laserausgabeeinstellbereich 1 A, is used. Within the laser output setting area 1 A, there is a data zone 1 B containing a plurality of tracks. The carriage 30 is guided by rails, which are not shown and which run along both edges of the carriage 30 , and driven by the VCM 15 to move in the radial direction of the optical disk medium 1 . An outer stopper 15 A is arranged on the side of the outermost periphery of a range of motion of the carriage 30 , and an inner stopper 15 B is arranged on the side of its inner most circumference.

As described above, in the photosensor 7 placed in a main body of the optical disk unit, its incident light or reflected light is intercepted by the intercepting projection 35 formed on the carriage 30 when the carriage 30 is in the laser output setting range 1 a is disposed for a laser diode, which is defined on the optical disc medium. 1 An output from the photo sensor 7 is input to the MPU 42. On the basis of the output of the photosensor 7 , the MPU 42 causes a current to flow into the VCM 15 through the VCM driver 8 , thus moving the carriage 30 in the radial direction of the optical disk medium 1 .

FIG. 15B shows a waveform of an output signal of the photo sensor 7. The output of the photo sensor 7 is high when the incident light of the light receiving device will be intercepted by the intercepting projection 35 when the carriage 30 is disposed in the Laserausgabeeinstellbereich 1 A for the laser diode.

Next, in conjunction with the flowcharts of FIGS . 16A and 16B, a procedure for positioning the carriage 30 in the laser output setting area 1 A for the laser diode for the purpose of setting the output of the laser diode or the intensity of laser light emitted from the stationary optical Unit comes, described, after the power is turned on to the optical disk unit implemented in the optical disk unit including the carriage 30 having the above components but not having a position sensor.

At step 1601 , it is judged whether or not a position sensor is on. In this control procedure, the position sensor designates the photosensor 7 . The state in which the position sensor 7 is on is a state in which the incident light from the photosensor 7 is intercepted by the intercepting protrusion 35 formed on the carriage 30. The first judgment as to whether the position sensor 7 is turned on or not is aimed at judging at what position on the optical disk medium 1 the carriage 30 is located. If the position sensor 7 is on, the carriage 30 has already been arranged at a position within the Laserausgabeein setting area 1 A for the laser diode. If the position sensor 7 is off, the carriage 30 is located in any other area except the laser output setting area 1 A for the laser diode on the optical disk 1 medium. A procedure for positioning the carriage 30 in the Laserausgabeeinstellbereich 1 A for the laser diode, depending on whether the carriage 30 is located in the laser output setting range for the laser diode or not, when the power supply of the optical disk unit is turned on will be described below.

(1) When the carriage 30 is in the laser output setting area for the laser diode is arranged

In this case, it is found at step 1601 that the position sensor 7 is on. Control therefore transfers to step 1602 . A current I is applied to the VCM 15 by means of the VCM driver 8 to move the carriage 30 to the inner periphery of the optical disk medium 1 side. With the application of the current I, the carriage 30 moves toward the inner periphery of the optical disk medium 1 . At step 1603 , it is judged whether or not the position sensor 7 is turned off, that is, whether the carriage 30 has left the laser output setting range 1 A for the laser diode. If the position sensor 7 is off, control goes to step 1605 . If the position sensor 7 is not turned off, control goes to step 1604 . At step 1604 , the current I is increased. Control then returns to step 1603 . At step 1603 , it is judged again whether the position sensor 7 is turned off or not.

At step 1605 , to which control passes when it is found at step 1603 that the position sensor 7 is turned off, a current i is applied to the VCM 15 by means of the VCM driver 8 to drive the carriage 30 to the outer periphery of the optical disc medium 1 to i bewe gene. the polarity of the current is opposite to that of the current I. With the application of the current i, the carriage 30 moves toward the outer periphery of the optical disk medium 1 . In step 1606, it is judged whether the posi tion sensor is switched 7 or not, that is, whether the carriage 30 has entered into the Laserausgabeeinstellbereich 1 A for the laser diode. If the position sensor 7 is off, control goes to step 1607 . The current i is increased. At step 1606 , it is judged again whether or not the position sensor 7 is turned on.

If the position sensor 7 is found to be on at step 1606 , control goes to step 1608 . The value of the current i at that time is reserved as the interruption current Aout. At step 1609 , a current I is applied to the VCM 15 through the VCM driver 8 to move the carriage to the inner periphery of the optical disk medium 1 again. The application of the current I causes the carriage 30 to move toward the inner periphery of the optical disk medium 1 again . At step 1610 , it is judged whether the position sensor 7 is turned off again or not. If it is found in step 1610 that the position sensor 7 is not turned off, control goes to step 1611 . Current I is increased and control returns to step 1610 . At step 1610 , it is judged again whether the position sensor 7 is turned off or not.

If the position sensor 7 is found to be off at step 1610 , control goes to step 1612 . The value of the current I at that time is reserved as the non-interruption current Ain.

As mentioned above, when the power supply of the optical disc medium 1 is turned on, if the car is 30 in the Laserausgabeeinstellbereich 1 A for the laser diode, the carriage 30 temporarily evacuated from the area. The value of the current i that flows when the car 30 re-enters the area is stored as the interruption current Aout. The value of the current I that flows when the car 30 comes out of the area immediately after entering the area is stored as the non-interruption current Ain.

(2) When the carriage 30 is outside the laser output adjustment range for the laser diode is arranged

In this case, it is found at step 1601 that the position sensor 7 is off. Control transfers to step 1613 . A current i is applied to the VCM 15 through the VCM driver 8 to move the carriage 30 to the outer periphery of the optical disk medium 1 . The application of the current i causes the carriage 30 to move toward the outer periphery of the optical disk medium 1 . At step 1614 , it is judged whether the position sensor 7 is turned on or not, that is, whether the carriage 30 has entered the laser output setting area 1 A for the laser diode. In step 1615 , the current i is increased and control returns to step 1614 . At step 1614 , it is judged again whether the position sensor 7 is turned on or not.

If the position sensor 7 is found to be on at step 1614 , control goes to step 1616 . A current I is applied to the VCM 15 through the VCM driver 8 to move the carriage 30 to the inner periphery of the optical disk medium 1 . The polarity of the current I is opposite to that of the current i. The application of the current I causes the carriage 30 to move toward the inner periphery of the optical disk 1 medium. At step 1617 it is judged whether the position sensor 7 is off or not, i.e., whether the carriage 30 come out of the Laserausgabeeinstellbereich 1 A for the laser diode. If the position sensor 7 is on, control transfers to step 1618 . The current I is increased. At step 1617 , it is judged whether or not the position sensor 7 is turned off.

If the position sensor 7 is found to be off at step 1617 , control goes to step 1619 . The value of the current I at that time is reserved as the interruption current Ain. At step 1620 , the current i is applied to the VCM 15 through the VCM driver 8 to move the carriage to the outer periphery of the optical disk medium 1 . The application of the current i causes the carriage 30 to move toward the outer periphery of the optical disk medium 1 . At step 1621 , it is judged whether the position sensor 7 is turned on again or not. If the position sensor 7 is not turned on, control goes to step 1622 . The current i is increased. At step 1621 , it is judged whether the position sensor 7 is turned on or not.

If the position sensor 7 is found to be on at step 1621 , control goes to step 1623 . The value of the current i at that time is reserved as the non-interruption current Aout.

As mentioned above, when the power supply of the optical disc medium 1 is turned on, if the car is 30 outside the Laserausgabeeinstellbereiches 1 A for the laser diode, the carriage 30 temporarily moves gabeeinstellbereich 1 A for the laser diode in the laser equipment. The value of the current I that flows when the carriage 30 comes out of the area is stored as the interruption current Ain. The value of the current i that flows when the car 30 enters the area immediately after it comes out of the area is stored as the non-interruption current Aout.

Thus, after measuring the interruption current Ain and the non-interruption current Aout flowing when the carriage 30 is within the laser output setting range for the laser diode and those flowing when the carriage 30 is outside of it, control goes to step 1624 . Average values of the interrupting currents Ain and non-interrupting currents Aout are calculated as holding current values Ahld. At step 1625 , the holding current values Ahld are set in the VCM driver 8 . Using the holding current values Ahld, the carriage 30 can be locked while it is offset to be within the laser output setting range for the laser diode.

The reason why the values of currents flowing when the carriage 30 reciprocates are measured and averaged is that a current can be roughly changed in steps and an operation time can be shortened eventually. Another reason is that a current to be changed is different depending on the direction in which the carriage 30 is moved.

The processing described in conjunction with Figs. 16A and 16B is carried out when the optical disk unit is placed horizontally. In contrast, when the optical disk unit is tilted when the optical disk unit is tilted toward the outer periphery of an optical disk medium, for example, if the carriage 30 is disposed on the inner periphery of the optical disk medium, the above processing poses problems. According to the above processing, even if the optical disk unit were inclined, a current would be set which is used to move the carriage 30 toward the outer periphery of an optical disk medium, assuming that the optical disk unit is arranged horizontally . Since the tilt of the optical disk I would act on the integrated current, the carriage 30 could be the optical disc medium are accelerated toward the outer periphery, and discharged 15 A against an external stopper.

In this case, the carriage 30 rebounds due to a pulse resulting from the collision with the outer stopper 15 A, back to the inner periphery of the optical disk medium. As a result, the position sensor 7 is turned on and off for a short period of time. This can make it impossible to precisely set a holding current Ahld. In this case, since a precise holding current Ahld cannot be obtained, the carriage 30 cannot be stopped. The carriage 30 holds, while it abuts against the outer stopper 15 A.

To overcome the above problem, a process is added: a difference Adif between the measured interruption current Ain and non-interruption current Aout is calculated; and when the difference Adif becomes equal to or smaller than a certain value, the interruption current Ain and non-interruption current Aout are measured again. This example of control will be described using the flowchart of FIG . The processing from step 1601 to step 1623 is identical to the procedure described in connection with FIGS. 16A and 16B. The description of the processing is omitted.

When step 1612 or 1623 of the processing described in FIGS. 16A and 16B is completed, control goes to step 1702 of the processing in FIG . At step 1702 , the difference Adif (absolute value) between the measured interruption current Ain and the non-interruption current Aout is measured. At step 1702 , it is judged whether or not the difference Adif is equal to or greater than a given reference value As1. If the value As1 is greater than the value Adif, control returns to step 1601 . The processing from steps 1601 to 1623 is repeated. In contrast, if it is found at step 1702 that the value As1 is equal to or less than the value Adif, control goes to step 1624 . An average of the interruption current Ain and the non-interruption current Aout is calculated as the holding current Ahld. At step 1625 the value of the holding current Ahld in the VCM driver 8 is set. With the holding current Ahld, the carriage 30 can be locked while it is offset to lie rich in the laser output setting area for the laser diode.

The reason why the above processing is carried out is that when the optical disk unit is inclined toward the outer periphery of an optical disk medium, since the carriage 30 turns the position sensor 7 on and off for a short period of time, a difference between measured currents becomes smaller than a difference between normally measured currents. Incidentally, since the carriage 30 is arranged at a position where the position sensor 7 is on, the second measurement can be carried out without any problem.

Fig. 18 shows an example of the current control for the VCM described in connection with Figs. 16A and 16B, in which when the power to the optical disk unit is turned on, the output of the position sensor 7 is high. In Fig. 18, a current to be applied to the VCM and the output of the photosensor 7 are plotted with respect to time. In Fig. 18, time interval (a) coincides with step 1601 to step 1604 , time (b) coincides with step 1605 , time interval (c) coincides with step 1606 to 1607 , time (d) coincides with step 1608 , the time interval (e) coincides with step 1609 to step 1611 and the point in time (f) coincides with step 1612 .

Fig. 19A shows an example of the current control for the VCM described in connection with Figs. 16A and 16B, in which when the power to the optical disk unit is turned on, the output of the position sensor 7 is low. In Fig. 19A, a current to be applied to the VCM and the output of the photo sensor 7 are plotted with respect to time. Time (b) 'coincides with step 1616 , time interval (c)' coincides with step 1617 to 1618 , time (d) 'coincides with step 1619 , time interval (e)' coincides with step 1620 to step 1622 , and the point in time (f) 'coincides with step 1623 .

Fig. 19B shows an example of the current control for the VCM described in connection with Fig. 17 in which when the power of the optical storage device is turned on, the output of the position sensor 7 is low. In this case, the output of the photo sensor 7, at time (b) "However, since 30 collides driven high. Carriage with the outer stoppers 15 A and rebounds, the output signal of the photo sensor 7, at time (d)" vice versa. In this case, the processing described in Fig. 19A can be carried out after time (f) ".

Next, an optical storage device of FIG third embodiment of the present invention ben. Before the optical storage device, a conventional Licher lens actuator briefly described.

In an optical disk unit, a carriage is placed on with an objective lens mounted, through a VCM in moved in the radial direction of an optical disk medium. A Tracking actuator for fine adjustment of the object tivlinse inside the car is locked to the VCM, whereby each track is accessed (search). The conventional That is why the wagon contains a position sensor for Detek animals of the position of the carriage and a lens position sor to detect the position of the objective lens on the Dare.

An optical storage device of the present invention Finding is however without a position sensor and lens position sensor as the optical storage device is made thinner is.

Fig. 20 is an enlarged view of a lens actuator 62 mounted on a carriage. A movable part of the actuator 62 includes a lens holder 621 , a focus coil 65 and tracking coils 66 a and 66 b. The lens holder 621 is made of a thermosetting resin or the like so that an objective lens L can be held movable in a tracking direction or a focus direction. The focus coil 65 is attached to a wall of a central opening of the lens holder 621 using an adhesive. The tracking coils 66 a and 66 b are attached using an adhesive on an upper surface opposite the wall on which the focusing coil 65 is attached.

Further, the two tracking coils 66 a and 66 b, which adjoin the left and right parts of one side of the focus coil 65 , are wound in a direction which is perpendicular to the plane of winding of the focus coil 65 substantially. One end of each of the tracking coils 66 a and 66 b protrudes from the edge of a yoke 63 , whereby a magnetic circuit is formed on the right and left sides of the yoke. In other words, parts of the tracking coils 66 a and 66 b, of which magnetic fluxes expand vertically, are arranged outside the magnetic scarf device, so that the tracking coils are not affected by another magnetic flux. Control is thus carried out so as not to cause mechanical vibrations.

The magnetic circuit of the actuator 60 includes a magnet 64 , a yoke 61 c, a yoke 61 d (see FIG. 14C) and a cover yoke 63 . The magnet 64 is arranged on a Actuate gerbasis 61 so that the magnet 64 of the focus coil 65 lies opposite in the central opening of the lens holder 621 , which forms the movable part of the actuator 62 . The yoke 61 c includes the bent part of the actuator base 61 for receiving magnetic force from the magnet 64 . The bent part of the yoke 61 d, which is not shown, faces the yoke 61 c. The cover yoke 63 is shaped like a letter U to connect the yokes 61c and 61d .

The lens actuator 62 further comprises four wires 67 a, 68 a, 69 a and another (the one wire is not ge shows), four attenuators 67 b, 68 b, 69 b and another (one link is not shown), and four connecting plates 67 d, 68 d, 69 d, and another (the one plate is not shown). The four wires 67 a, 68 a, 69 a and one other (one wire is not shown) hold the movable part of the actuator 62 . The four terminal plates 67 c, 68 c, 69 c and another (one plate is not shown) are connected using an adhesive, with their holes with projections 62 a and 62 b of the lens holder in engagement, and hold the ends of the wires on the side of the objective lens. The four terminal plates 67 d, 68 d, 69 d and the other (one plate is not shown) are connected to a wire holder which is engaged with an edge of the actuator base 61 using an adhesive. The four damping members 67 b, 68 b, 69 b and another (one member is not shown) are used to absorb the vibrations of the wires.

One end of an FPC 39 c extends to the Drahthal ter 622 and is soldered to the four connection plates on the wire holder 622. The four connection plates on the Lin senhalter 621 are soldered to the two lines of each of the focus coil 65 and the tracking coils 66 a and 66 b. The focus coil 65 , the tracking coils 66 a and 66 b and the FPC 39 a are thus connected. Electrical connections are thus achieved without it being necessary to lead thin lines of the coils to the outside. No interruption is therefore feared. Thus, the reliability can be improved.

Further, the four wires and the terminal plates, which are arranged on both edges of the wires, by pressing a leaf spring material or linear spring material using a pair of dies (U-shape) Herge provides, defining a state in which two right and left wires are connected. The two right and left wires are then mounted in the wire holder 622 with them connected to each other (in the U-shape). Then the connection is cut out. The use of the wire assembly thus produced simplifies the handling or handling of small parts and improves the assembly efficiency.

The actuator base 61 is screwed to the lens carriage 30 through fixing sections 61 a and 61 b formed in the bent fragments of the actuator base 61 with all of the parts mounted on the actuator 62.

In the lens actuator 62 having the above components, a VCM plays a key role in moving the objective lens L during coarse control or search control. In search control, it is important to approach a speed at which the fine control moves the objective lens to the closest possible value of zero. In order to control the search speed so that the end speed becomes 0, it is necessary to measure the search speed precisely. The search speed can be measured using a zero-cross pulse generated when the objective lens L crosses a track. A higher speed can be calculated using the number of pulses sampled during a unit of time. A lower speed can be calculated using pulse spacing. A signal used to measure the speed is a tracking error signal in both cases.

The objective lens L is moved on a VCM carriage by a system whose degree of freedom is 2 , that is, a tracking actuator. It cannot generally be said that "the tracking error signal represents a value equal to a function of the position of a VCM." The tracking error signal always includes a component indicative of the position of a lens within the carriage (i.e., an output of a lens position sensor). If the carriage is accelerated so that it is moved at high speed during searching or the like, it is prophesied that the lens shifts greatly due to inertia on the carriage. The tracking error signal therefore represents a value equal to a function of the combination of the position of the VCM and the output of the lens position sensor.

If the lens position sensor is used, can a lock control of the lens on the carriage, a so-called "lens lock servo control", under Ver application of an output signal of the lens position sensor are executed. In this case, "the tracking error signal represents a value that corresponds to a function is the same as the position of the VCM. "

In an optical storage device that has neither a position sensor nor a lens position sensor, a lens is locked on a carriage according to the following method (1 ) or ( 2 ):

• 1. The lens is at the same acceleration as that of the chariot accelerates, causing the appearance of a relative displacement is prevented; or
• 2. The carriage is moved so slowly that the lens does not vibrate.

However, the controller ( 1 ), since the acceleration performance is different between an actuator and a VCM, poses a problem that the actuator and the VCM cannot provide the same acceleration even if the same current is applied to the actuator and the VCM. The controller ( 2 ), since a search time increases, poses a problem that the increase may impair access to a track.

The third embodiment therefore realizes a tax ersystem, in which "components in a high frequency band that an increase in the difference in acceleration performance cause compared to that of an actuator, not included and a search time will not increase. "In short In other words, the third embodiment introduces a structural vibra minimized acceleration path (SMART) control, which minimizes structural vibrations.

The SMART control is used as a control system that hardly generates vibrations by a high frequency band be induced in a control object, in an effort to for example, in the field of a magnetic disk unit, the Secondary resonance of a magnetic head caused by the search control is caused to master. The SMART control is such that the occurrence of residual vibration (1 to 2 kHz) a support spring, which is controlled by the fine control of the magnetic head fes (which is a frequency band of several hundred frequencies treated) cannot be fully controlled, even is suppressed during search control. That is, the The control to be executed is not directed towards the generated To suppress vibrations but to set a goal to present acceleration trajectory that does not have any vibration evokes.

Since the lens actuator 62 shown in Fig. 20 does not have a lens position sensor, a lens position signal cannot be generated. The VCM is therefore controlled in accordance with the SMART control system that minimizes structural vibrations so that when the car is moved, almost no pulse is applied to the VCM that would cause abrupt acceleration or deceleration.

Let us consider the VCM as a motion model. The equation of motion is expressed as follows:

m. d ² x (t) / dt ² = (B1). i (t

where x (t) indicates the position of the VCM and i (t) indicates a coil current. If the position and the speed of the VCM are used as quantities of a state, the equation of state results as follows:

x (t) = Ax (t) + bi (t)

where x (t) indicates the position of the VCM. When rewriting the equation of state becomes as follows:

Assuming that the environmental conditions for the model are expressed as follows:

a target path for the acceleration path control is given by the function x (t), which minimizes the following power function:

In other words, the function x (t) which is "a change of a stream that is sent to the VCM within a search time is to be applied, minimized "defines an acceleration path that minimizes structural vibrations is effective. That means the SMART control, the struktu Real vibration minimized can be used as the control system which is discussed below.

• 1. It is assumed that a search time is T.
• 2. A current profile i (t) is set, the one Defined current, which, if possible, is not a high frequency component contains.

A procedure for solving the above expression according to the The calculus of variations is at the core of the present invention dung not included. The detailed solution procedure will be omitted and only a solution is presented.

Assuming that a time t is normalized by a search time T, solutions are provided like the expressions below, where a (tn) is an acceleration, v (tn) is a speed, x (tn) is a position, and tn = t / T is set. Target drive profiles are shown in Figures 21A through 21C. More specifically, FIG. 21A shows a drive profile at acceleration, FIG. 21B shows a drive profile at speed, and FIG. 21C shows a drive profile at position.

a (tn) = L / T ² . {120tn ³ - 180tn ² + 60tn}

v / tn) = L / T. {30tn ⁴ - 60tn ³ + 30tn ² }

x (tn) = L. {6t ³ - 15tn ⁴ + 10tn ³ }

Thus, the target drive profiles can be relatively simple can be expressed in terms of polynomials. It is easily possible the polynomials using a digital signal processor (DSP). For example, if a search operation A car is taken, will be a target acceleration and target speed based on the position of the Car and a distance calculated by the car during the search operation is moved. A search stream on the base the results of the calculation are then fed to a VCM.

Finally, an optical disk unit of the fourth embodiment of the present invention will be described. Before the optical disk unit, the lens locking by the conventional lens actuator will be briefly described in conjunction with Fig. 22B.

Fig. 22B shows the configuration for controlling the conventional lens actuator. Referring to Fig. 22B, a base 201 , a carriage 202 , a lens actuator 204 , a VCM 205 , an objective lens 209 , an optical disk medium 213 , a position sensor 216 , a lens position sensor 217 , a photodetector 218 , a differential circuit 219, and Phase compensators 220 <06703 00070 552 001000280000000200012000285910659200040 0002019655037 00004 06584 / BOL <and 221 shown. In an optical disk unit, tracking control is carried out with respect to a row of tracks so that the objective lens 209 can irradiate a light spot on an intended track of the optical disk medium 213. A feedback loop for giving a final value of 0 on a tracking error signal provided by photodetector 218 is established. Incidentally, the tracking error signal contains noise resulting from any one of the following adverse effects: 1. Displacements of a spindle motor and the optical disk medium 213.2. an error in the position of a row of tracks with respect to a reference position, 3. other structural vibrations, or 4. Influence of an ID division. Noise resulting from all of the above adverse effects from the displacements of the spindle motor and optical disk medium 213 is low in frequency and large in amplitude. Noise resulting from the error in the position of a row of tracks, the other structural vibrations and the influence of ID division is high in frequency and small in amplitude. In the optical disk unit, in simultaneously controlling two mechanisms, a coarse movement mechanism and a fine movement mechanism, by assigning different control frequencies to the mechanisms according to the characteristics of the mechanisms, the dual servo control is applied. In dual servo control, lens actuator 204 is controlled by the feedback loop handling the tracking error signal, while VCM 205 is controlled by a feedback loop handling the output of lens position sensor 217. Alternatively, as shown in Fig. 22B, the speed of the VCM 205 (differential of the output of the position sensor) can be fed back for the purpose of damping. Due to the above configuration, the carriage 202 follows the movement of the lens 209. A large amplitude component of an error signal indicating that displacement brings an intended track out of the movable range of the lens actuator 204 may be in the form of the output of the lens position sensor 217 can be sent to the VCM 205. Thus, the combination of the lens actuator 204 and the VCM 205 forms a dual servo control system. 23A to 23C show a tracking error signal (denoted by TES) generated during the conventional search, a drive speed of the VCM 205, and an output of a lens position sensor (lens position signal). Depending on the speed of the VCM 205, the carriage 202 follows the movement of the lens 209. The lens 209 is locked in the center of the carriage 202 during the search. In contrast, the optical disk unit of the fourth embodiment uses the lens actuator 62 described in connection with Fig. 20, but does not include a position sensor and a lens position sensor. Fig. 22A shows the configuration of the lens actuator 62 of Fig. 20 in the form of a block diagram in the same manner as Fig. 228 showing the conventional lens actuator. Referring to Fig. 22A, an optical disk medium 1, a VCM 15, a base 20, a carriage 30, a lens actuator 62, an objective lens L, a photodetector 218, a filter 223, phase compensators 220, 224 and 226, a low-pass filter (LPF) 225, a spring 230, and switches SW1 and SW2 are shown. Differences in the optical disk unit of the fourth embodiment with respect to a conventional unit in terms of hardware are that the position sensor and the lens position sensor are not included and that the lens actuator 62 is supported on the carriage 30 by the spring 230. When the lens actuator 62 is supported by the spring 230 on the carriage 30, the following differences result from the conventional unit: 1. Due to the lack of bearings, no undesired frictional forces occur, and the actuator 62 is provided with a restoring force (a force proportional to a displacement) so that it is returned to an equilibrium position. Since the lens actuator 62 is supported by the spring 230, a generated tracking error signal (TES) indicates an equilibrium position at which the accelerating force of the lens actuator 62 and the spring force are balanced. In other words, due to the use of the spring-loaded actuator, the tracking error signal becomes a signal that contains a component of a lens position sensor output from the start. Fig. 23D shows a tracking error signal generated in the present invention when the lens is moved only with the VCM fixed. Fig. 23E shows a lens signal generated by the lens actuator 62 having the above components. It can be seen from the two signals that the envelope of the tracking error signal with its bias component removed is used as the waveform of the lens signal. In the present invention, the tracking error signal from the components shown in Fig. 22A is passed through the low pass filter 225 to remove high frequency components. The phase compensator 226 then performs the phase compensation. This results in a false lens signal shown in Fig. 23F. If the wrong lens signal, in which its noise is removed, is used, the objective lens L can be locked by the lens actuator 62 during the search of the carriage 30, although no lens position sensor is included.

Claims (3)

An optical storage device for reproducing information from and / or recording information on an optical storage medium ( 1 ) by irradiating a light beam generated by a stationary optical unit (40 ) incorporated in a main body onto the optical Storage medium ( 1 ) by a carriage ( 30 ) which moves in the radial direction of the optical storage medium ( 1 ) within the main body by a drive mechanism, in a state in which the optical storage medium ( 1 ) loaded in the main body is rotated, on which carriage ( 30 ) an actuator ( 62 ) is mounted for a lens which collects the light beam on the optical storage medium ( 1 ), in which the carriage ( 30 ) tends to oscillate due to the structure, With:
a moderate accelerating means which, when a search operation of the carriage with respect to the optical storage medium ( 1 ) is started, supplies the drive mechanism for the carriage with a current used to smoothly accelerate the carriage (30); and
a moderate decelerating means which, when the carriage ( 30 ) has approached a search target position during a search operation of the carriage ( 30 ) with respect to the optical storage medium ( 1 ), supplies the drive mechanism for the carriage ( 30 ) with a current which is used, to slow down the carriage ( 30) gently. 2. The optical storage device according to claim 1, which does not include position sensors for detecting the position of the carriage with respect to the main body and for detecting the position of the lens actuator ( 62 ) with respect to the carriage ( 30 ), 3. The optical storage device according to claim 1 or 2, wherein, during a search operation of the carriage (30 ), the mode accelerating means and the moderate decelerating means calculate a target acceleration and target speed based on a position of the carriage ( 30 ) and a distance by which the carriage ( 30 ) is moved during the search operation, and supply the drive mechanism for the carriage (30 ) with a search current according to the calculation results.