JPH06187747A - Information track retrieving device - Google Patents

Abstract

PURPOSE:To always stably and highly speedily retrieve a desired information track without being affected by a track pitch difference. CONSTITUTION:This device possesses a traverse speed detecting means 25 for a pickup means for traversing a track by the output of a tracking error detecting means 18, a sensitivity switching means 26 for switching the sensitivity of the traverse speed detecting means and a reference signal generating means 31 for generating the speed reference signal of the pickup means at the time of retrieval. The retrieval speed is controlled by the output of a comparison between the output of the sensitivity switching means 26 and the output of the reference signal generator 31, and in the unstable state of information about a track pitch after the replacement of recording carriers, the stability can be enhanced by setting the sensitivity switching means 26 to make the track pitch to be in the narrowest state and, after clarification of the pitch, to an optimum value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information track searching device for searching a desired information track from a record carrier having a large number of information tracks.

[0002]

2. Description of the Related Art As a conventional apparatus, an optical pickup having a semiconductor laser, a photodetector and the like built-in is moved linearly from the inner peripheral side to the outer peripheral side of a disk-shaped record carrier, and the record carrier is moved. There is an optical reproducing device that reproduces a signal recorded on a record carrier by rotating it at a predetermined rotation speed.

A width of 0.6 μm and a pitch of 1.
Micro tracks of 6 μm are provided spirally or concentrically, and in an optical pickup, a light beam generated by a semiconductor laser is focused on a track on a record carrier by an objective lens as a pickup element to irradiate the track on the record carrier. The signal recorded in is read out. Therefore, tracking control is performed on the objective lens so that the light beam is always positioned on the track.

The tracking control error signal is obtained from the reflected light from the record carrier, and the tracking control is performed by adding this signal to a tracking actuator for moving the objective lens in a direction substantially perpendicular to the track direction.

Since a large number of tracks are provided on the record carrier, a search means is indispensable for searching the track on which desired information is recorded.

The search for the desired track is performed based on the address provided for each track on the record carrier.
The tracking control is disabled and the optical pickup is moved in the radial direction of the record carrier by the number of tracks corresponding to the difference between the address of the currently reproduced track and the address of the desired track.

In such an optical reproducing apparatus, it is required that a desired track can be searched at high speed. For that purpose, it is necessary to control the moving speed of the optical pickup with high accuracy. Therefore, the position and the moving speed of the optical pickup are calculated from the tracking error signal to improve the accuracy of the moving speed detection and realize the high speed search (for example, Japanese Patent Application No. 59-115).
085).

The tracking control error signal is a sinusoidal signal when the light beam on the record carrier crosses a track. Since one cycle of this sinusoidal signal corresponds to the time when the light beam crosses one track, the conventional optical reproducing apparatus utilizes this to determine the moving speed of the optical pickup.

The detection principle will be briefly described with reference to FIG. In the same figure, (a) shows the information track and the spot position of the light beam, and shows the state where the beam spot crosses from left to right of the track from (1) to (5). (B) shows the reflected light intensity distribution from the disc on the two-division tracking detector which is installed on the optical pickup and detects the tracking error, and (c) shows the tracking which is the differential signal of the two-division detector. The error is shown. The polarity of the tracking signal changes depending on optical conditions such as the height of the information track. Generally, when λ is the incident light wavelength, the distribution of the light reflected and diffracted in the vicinity of an odd multiple of λ / 8 is Imbalances with different polarities occur on both edges. By utilizing this, the positional relationship between the information track and the light beam can be detected. This method is called the far-field method or push-pull method, and is the most general method for detecting a tracking error of a recordable disc with a pre-groove. For the above reason, as shown in FIG. 8, a tracking signal of a substantially sinusoidal wave as shown in (c) is obtained depending on the positional relationship between the information track and the beam spot. Using this tracking signal, the light beam is made to accurately follow the track, and at the time of track search to search for an arbitrary track, the position of the light beam is detected by counting the number of crossings of the tracking signal and the movement of the optical pickup is moved. The position of the optical pickup is controlled by separately providing a speed detector for detecting the speed or detecting the moving speed of the light beam by measuring the period of the tracking signal.

[0010]

However, in order to meet the recent demand for higher density and higher capacity, the pitch of the tracks provided on the record carrier is made narrower than in the past and the number of tracks is increased. Carriers have also become manufactured. As a result, even when the optical pickup traverses the tracks at the same speed, it is understood that the frequency becomes higher in the narrow track pitch (e) than in the wide track pitch (d) as shown in FIG. .
For example, the current track pitch is 1.6 μm, but when the density is increased to 1.2 μm, it is 1.33 times,
When it is set to 1 μm, the track crossing frequency is 1.6 times.

When a track on a record carrier provided with a track having a track pitch different from the conventional one is searched for by using the method for obtaining the moving speed of the optical pickup from the error signal of the tracking control as described above, For the above reasons, the speed detection sensitivity of the moving speed of the optical pickup changes greatly depending on the track pitch, which makes the control system of the search unstable and increases the search time and lowers the search accuracy. Had.

The present invention has been made in view of the above points, and an object of the present invention is to provide an information track search apparatus capable of stably and quickly searching for a desired track even when using record carriers having different track pitches.

[0013]

According to the present invention, there is provided a pickup means for recording information or reproducing a signal from a record carrier having a track on which the information is recorded, and a signal reproduced by the pickup means. Signal processing means for detecting address information indicating a track position and information such as recorded programs and data, and tracking error detecting means for detecting a positional deviation between the reproduction position of the pickup means on the record carrier and the track on the record carrier. A first moving the reproduction position of the pickup means on the record carrier in a direction substantially perpendicular to the track direction on the record carrier;
And second moving means, and first control means for driving the first moving means according to the output of the tracking error detecting means so as to control the reproduction position of the pickup means so that it is always on the track. Crossing number detection means and crossing speed detection means for detecting the number of tracks and speed at which the pickup means crosses tracks from the output of the tracking error detection means, sensitivity switching means for switching the sensitivity of the crossing speed detection means, and desired And a reference signal generating means for generating a speed reference signal for the pickup means in response to the output of the crossing number detecting means when searching for a track, and the output of the crossing speed detecting means whose sensitivity is switched by the sensitivity switching means. The second moving means is controlled by the output obtained by comparing the outputs of the reference signal generator.

Alternatively, an independent speed detecting means of the pickup means is provided, and when the track pitch is unknown, the speed detector is compared with the reference signal generator, and after the track pitch is known, the output of the speed detector is changed to the sensitivity by the switch means. The crossing speed detecting means is switched to control the second control means, or the coefficient switching means of the reference signal generator is provided, and the coefficient switching means and the crossing speed detecting means are compared, or the coefficient switching means and the speed detecting means. The second control means is controlled by comparing the outputs of the above.

Further, the sensitivity switching means and the coefficient switching means are switched by reading the information of the control track at a specific track position.
Alternatively, a configuration is provided in which a predetermined number of tracks are searched before using the control track, and the switching means is set to the optimum state by judging the required time.

[0016]

According to the present invention having the above-mentioned structure, the moving speed of the moving body is detected by the speed detecting means when the record carrier is replaced, or the speed is low but the stability is emphasized. Since the control is performed, it is possible to stably search for a specific track such as a control track on which medium information is recorded or a track having a maximum address number without being affected by the difference in track pitch of the record carrier. In addition, the medium type information such as the track pitch recorded on the control track or the maximum address number is read by the signal processing means to determine the type of medium, or the track pitch is determined by a test search for searching a certain number of tracks. After that, the sensitivity of the traverse speed detecting means is switched to a sensitivity that matches the track pitch of the record carrier, or the coefficient switching means of the reference generator is switched to control the moving speed of the pickup means in an optimum state. Track search can be performed quickly and stably.

Further, by implementing a certain number of track searches to switch the state variable of the control system for controlling the second moving means to an optimum state, many kinds of track pitches can be supported. In addition, it is possible to realize a stable search control system that can cope with changes in temperature, changes with time, and the like, while simplifying device adjustment.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment. In FIG. 1, 1 is a disk as a record carrier, 2 is a motor for rotating the disk 1, 3 is a light source, and 5 is divergent light from the light source. Coupling lens for changing to parallel light, 6 is a polarization beam splitter that changes the optical path by passing the incident light and reflecting the reflected light from the disc, 7 is a quarter wavelength plate that rotates the polarization plane of light by 90 degrees, and 8 is all A reflecting mirror 9 is a converging lens for converging the light beam generated from the light source 3 onto the record carrier, 1
1 is a photodetector, 13 is a mount on which the objective lens 9 and the like are mounted,
Reference numeral 14 is a linear motor coil, 15 is a tracking coil, 16 and 17 are amplifiers for converting the current of the photodetector into voltage to amplify the signal, 18, 32 and 40 are differential amplifiers, 19
Is a tracking control circuit composed of a filter for phase compensation, 22 is a drive circuit for amplifying the power supplied to the tracking coil, 23 is a cross detection circuit for detecting the number of tracks crossed from the tracking signal, 24 is a microcomputer, 20, 35 are switches, 25 is D /
A converter, 26 is a variable gain amplifier, 27 is an address input device, 28 is an adding circuit for adding the signals of the amplifiers 16 and 17, 29 is a signal reading circuit for reading address signals and data information recorded on the disc, Reference numeral 30 is a counting circuit for counting the number of tracks traversed, 31 is a speed reference generation circuit, 34 is a speed control circuit, 36 is a drive circuit for power amplification of a signal supplied to a linear motor coil,
Reference numeral 48 is an oscillation circuit for generating a clock of a micro computer, 49 is a jump circuit for synthesizing jump pulses that move to an adjacent track while performing tracking control,
Reference numeral 50 is an adder circuit for adding a jump pulse to the tracking control system.

The operation of the information track search device configured as described above will be described. The record carrier 1 is a motor 2
It is attached to the rotating shaft of and rotates at a predetermined rotation speed. A spiral track in which a signal is recorded is provided on the record carrier 1, and an address signal for identifying the position of the track is recorded on this track.
Further, there is a track on the record carrier 1 on which information indicating the type of the record carrier itself is recorded, and is used as a control track.

A light beam 4 generated from a light source 3 such as a semiconductor laser is collimated by a coupling lens 5, passes through a polarization beam splitter 6 and a quarter wavelength plate 7, is reflected by a total reflection mirror 8, and is a convergent lens. Irradiation 9 onto the record carrier 1.

The reflected light 10 of the light beam 4 reflected by the record carrier 1 passes through the converging lens 9, is reflected by the total reflection mirror 8, passes through the quarter-wave plate 7, and is then reflected by the polarization beam splitter 6. It is irradiated onto the photodetector 11.

The converging lens 9 is attached to a pedestal 13 via a leaf spring 12 as an elastic supporting member, and when an electric current is applied to a focus coil (not shown in the figure), the surface of the record carrier 1 is subjected to an electromagnetic force received by the coil. It is configured to move in a direction perpendicular to. The focusing lens 9 is focus-controlled so that the light beam 4 irradiated on the record carrier 1 is always in a predetermined focusing state, but the description thereof is omitted because it is not directly related to the present invention.

A total reflection mirror 8 and a linear motor coil 14 are attached to the pedestal 13, and when a current is applied to the linear motor coil 14, the linear motor coil receives electricity from a magnet (not shown) provided on the fixed side. The gantry 13 is configured to move integrally with the linear motor coil 14 and the total reflection mirror 8 by the magnetic force, over the entire recordable area in the radial direction of the record carrier 1. Further, a tracking coil 15 is attached to the converging lens 9, and when an electric current is passed through the tracking coil 15, the converging lens 9 is caused by an electromagnetic force received from a magnet (not shown in the figure) provided on the pedestal of the tracking coil. It is configured to be movable in a direction orthogonal to the upper track.

The photodetector 11 has at least a two-part structure, and its output is input to amplifiers 16 and 17. The signals of the amplifiers 16 and 17 are output to the differential amplifier 18, and the differential amplifier 18 outputs a signal according to the difference between the two signals. The signal of the differential amplifier 18 is a tracking error signal that represents the positional deviation between the light beam 4 focused on the record carrier 1 and the track.

The signal from the differential amplifier 18 is applied to the coil 15 via a tracking control circuit 19 composed of a filter, a switch 20, and a drive circuit 22 for power amplification. Therefore, the converging lens 9 is connected to the differential amplifier 18
Tracking control is performed so that the light beam 4 focused on the record carrier 1 is always positioned on the track. The switch 20 is for disabling the tracking control.

The tracking error signal when the light beam 4 on the record carrier 1 crosses a large number of tracks while the tracking control is inoperative is substantially sinusoidal as shown in FIG. 2 (A). Such a tracking error signal is input to a crossing detection circuit 23 composed of a hysteresis comparator or the like, and the crossing detection circuit 23 outputs a rectangular wave-shaped track crossing signal as shown in FIG. It

In the microcomputer 24, as shown in FIG.
(B) The time between c and d is measured using a clock input from the oscillation circuit 48, and the time when the light beam 4 on the record carrier 1 crosses one track, that is, the moving speed of the light beam is momentarily. can get.

The time when the light beam 4 on the record carrier 1 crosses one track measured by the microcomputer 24 is converted into speed data according to a speed conversion rule provided as a table in a memory inside the microcomputer 24 and is converted into D / Variable gain amplifier 26 via A converter 25
Is output to. The variable gain amplifier 26 includes an operational amplifier and a switch, and the gain is switched by the microcomputer 24. The signal of the variable gain amplifier 26 is input to the differential amplifier 32 via the switch 33.

Next, a search for a desired track will be described. The address signal of the desired truck is the address input device 27.
Input to the amplifier 24, the microcomputer 24
The address of the track where the light beam 4 on the record carrier 1 is located is read through the signal reading circuit 29 from the signal of the adding circuit 28 for adding the signals of 6 and 17, and the distance according to the number of tracks to the desired track is obtained. The direction is calculated, a value according to the distance to the desired track and the direction is set in the counting circuit 30, the switch 20 is opened to disable the tracking control, and the switch 35 is closed to enter the search state. When a current flows through the linear motor coil 14 and the gantry 13 moves, a signal in which the light beam on the record carrier 1 crosses the track is output to the differential amplifier 18, and the cross detection circuit 23 outputs the signal shown in FIG. A rectangular wave-shaped track crossing signal as shown is output. Counting circuit 3
0 counts the signals of the crossing detection circuit 23, and outputs a value corresponding to the distance to the desired track to the micro computer 24,
The speed reference signal generator 31 outputs it every moment. The speed reference generating circuit 31 outputs a value according to the value of the counting circuit 30 to the differential amplifier 32. Specifically, the D / A converter and the amplitude limiter are configured to output a constant amplitude and limit the maximum speed when the tracks are separated by a certain number or more. Here, the amplitude limiter may be an analog method such as a diode limiter or a method of digitally limiting the input of the D / A converter.
Therefore, the output of the speed reference generation circuit generally has a trapezoidal waveform with a steep rising and a slightly gradual falling, as seen from a waveform with the horizontal axis representing the time axis and the vertical axis representing the output. The differential amplifier 32 outputs a signal corresponding to the difference between the signal of the switch 33 and the signal of the speed reference generation circuit 31. The signal of the differential amplifier 32 is the speed control circuit 3 including an amplifier and the like.
4, a switch 35, and a drive circuit 36 for power amplification, which is applied to the linear motor coil 14. Therefore, the gantry 13 is drive-controlled according to the signal of the differential amplifier 32, and the speed of the light beam 4 converged on the record carrier 1, that is, the gantry 13 is controlled to a predetermined speed. It When the light beam 4 on the record carrier 1 arrives at the desired track, the counting circuit 30 sends this signal to the microcomputer 24. The microcomputer 24 opens the switch 35 to disable the speed control, closes the switch 20 to operate the tracking control, and again reads the address via the signal reading circuit 29. If the read address matches the address of the desired track, the search is terminated. If the address does not match, the search operation described above is repeated, or if it is located very close to the desired track, a microcomputer generates it. By synthesizing the acceleration pulse and the deceleration pulse to be generated by the jump circuit 49 and inputting them to the adding circuit 50, the track jump operation of jumping one or several tracks is repeated to search for a desired track.

Next, the operation of the apparatus when the record carrier is replaced will be described. The record carrier 1 is replaced,
The motor 2 is restarted, the light source 3 is turned on, the focus control (omitted) is activated, and after the light beam 4 is converged on the record carrier 1 in a predetermined state, the tracking control is activated to activate the light on the record carrier 1. After the address of the track on which the beam 4 is located is read through the address reading circuit 29, the control track provided at the innermost circumference or the outermost circumference where the disc type and track pitch information are recorded is searched.

However, the track pitch information of the record carrier is recorded on the control track, and when the control track is searched using the record carriers having different track pitches and the track pitch information is incorrect. Correspondence between the time when the light beam 4 crosses one track on the record carrier and the moving speed of the light beam becomes improper, so that the performance of the moving speed control of the light beam deteriorates and the search of the control track becomes unstable. Therefore, in the track search apparatus of the present invention, the above-mentioned variable gain amplifier is set to the highest gain, in other words, the narrowest track pitch is expected, so that the changed disk is stable at any track pitch. Then, the control track is searched. This is because when the track pitch is narrow, the amount of movement per track is smaller than that when the track pitch is wide, and therefore the speed detection sensitivity also decreases. For this reason, the variable gain amplifier when the track pitch is narrow is set to increase the gain. After that, the variable gain amplifier is set to the optimum gain for the track pitch information of the control track so that the subsequent track searches can be performed at high speed and in a stable state.

In this case, if the first drawn track is too far or too close to the control track,
A certain amount of track search such as 10000 tracks is tested and searched with the highest gain of the variable gain amplifier, the time required for the search is measured with a micro computer, and the track pitch is assumed by the time taken for the search, and the variable gain is adjusted. By resetting the gain of the amplifier to the optimum track pitch on the assumption, the search to the control track can be performed stably. This situation will be described with reference to FIG. In the figure, the horizontal axis represents the time required for searching a certain number of tracks and the vertical axis represents the moving speed of the light beam, and the speed profile of the light beam at the time of searching is schematically illustrated. When the track pitch of the changed disk is the most narrow, the setting of the variable gain amplifier and the state of the search control system match, so the speed rise (acceleration), which is the acceleration capability of the device, is almost the same. Since the descent (deceleration) is realized, the ideal solid line profile of V2 is obtained, and the search is completed at the required time of T1. However, if the track pitch of the changed disc is wide, the acceleration capability is the same, but the speed value calculated to be faster than the actual speed is used, so the actual maximum speed and deceleration curve are suppressed in reverse. It becomes the velocity profile of V2, and the search time of T2. Further, when the track pitch is wide, the distance to be searched and moved also increases in proportion to the track pitch. Therefore, the required time difference between T1 and T2 changes substantially in proportion to the square of the track pitch, and the actual track pitch is accurately calculated. It can be assumed. By setting the variable gain amplifier to the optimum gain state for the track pitch assumed by this required time difference, the subsequent speed profile can realize acceleration and deceleration with the optimum curve, similar to V1. Is what makes it possible. In addition, the stability of the track jump varies depending on the track pitch, so the pulse width of the track jump can be changed, the amplitude can be changed, and the width of the acceleration pulse and deceleration pulse can be changed based on the control track information or the result of the test search time. It is also possible to improve the stability of the track jump by adjusting or the like. This situation will be described with reference to FIG. In the figure, (C) shows the jump signal output from the jump circuit 49, and (D) shows the tracking signal output from the differential amplifier 18. Ja is the acceleration pulse,
Js represents a deceleration pulse, and jumps by Ja1 and Js1 are initially set in a state where the track pitch is wide and the jump pulse is narrow. In this case, it takes a long time to cross the track, but by resetting the proper acceleration / deceleration pulses Ja2 and Js2 according to the information of the control track or the result of the test search, a stable and high-speed track jump can be achieved. Has been realized.

If the track pitch set by the time required to retrieve a certain amount of tracks and the track pitch information of the control track are different, the track pitch information of the control track can be used to bring the track into a correct state. is there. Furthermore, even when the control system state changes significantly due to temperature changes or changes over time, the search time will change, so after setting the control track information, the information search as the actual operation is repeated. If the search becomes unstable or the search time becomes long, search for a certain amount of tracks again, and reset the gain of the variable gain amplifier so that the time required is the shortest. Is what you can do.

As described above, the speed detection output D
The speed of the A / A converter output is made variable by using a variable gain amplifier, etc. When the track pitch information is unknown, such as when changing the disc, the sensitivity is set so that stability is more important than speed. Track info,
Alternatively, by re-setting the variable gain amplifier so that the sensitivity setting corresponding to the regular track pitch is set according to the result of the time required for the test search, a track search device capable of stable and high-speed search even at various track pitches. Can be realized. Furthermore, by utilizing the test search function, it is possible to ensure stability against temperature changes and changes over time, and also to help stabilize and simplify the initial adjustment of the device.

It is also possible to change the gain of the variable gain amplifier and change the condition of the track jump pulse by assuming the track pitch information by measuring the time required for the track jump. However, the required time by the test retrieval can be set accurately because the result proportional to the square of the track pitch can be obtained as described above.

Next, a second embodiment of the present invention will be described with reference to FIG. In the figure, 33 is a switch, 46 is a light source, 37 is a photodetector for detecting the position of the light source, 38, 3
Reference numeral 9 is an amplifier, 40 is a differential amplifier, 41 is a high-pass filter, and the other components are the same as those in the first embodiment.

The operation will be described below with reference to FIG. The added component is as a speed detector of the gantry 13, and the light source 4 attached to the gantry 13
6 and the photodetector 37 attached to the housing of the device,
It is composed of amplifiers 38 and 39, a differential amplifier 40, and a high-pass filter 41. The light detector 37 is the light source 4
The two signals that change in accordance with the position of 6 and have polarities opposite to each other and the sum is constant are output. These two signals are amplified by the amplifiers 38 and 39, and then the differential amplifier 4
Input to 0. The differential amplifier 40 outputs a signal corresponding to the difference between the two signals, that is, a signal corresponding to the position of the light source 46. The signal of the differential amplifier 40 is differentiated by the high pass filter 41 to obtain a signal according to the moving speed of the light source 46. The signal of the high pass filter 41 is output to the switch 33.

In this embodiment, when the record carrier is replaced and the track pitch information is indefinite, the pedestal 13 is moved from the light source 46 attached to the pedestal 13 and the photodetector 37 attached to the housing of the apparatus. Since the speed is detected and used as the moving speed of the light beam 4, it is possible to stably search the control track without the moving speed control system being affected by the difference in track pitch. Further, instead of searching the control track, when searching for the track of the maximum address provided at the innermost or outermost position of the record carrier, the mount 13 is set to the mechanical stopper provided at the innermost or outermost position. However, since the speed of collision with the mechanical stopper can be controlled correctly at this time, the pedestal 13, the total reflection mirror 8 and the converging lens 9 are not damaged by excessive impact.

Since the light generated by the light source 46 attached to the pedestal 13 is not converged and used on the photodetector 37, the pedestal 1 output from the differential amplifier 40 is used.
The signal corresponding to the position of 3 has a lower accuracy than the tracking error signal output from the differential amplifier 18, and is not suitable as a speed detector for high-accuracy and high-speed speed control.

In this embodiment, after the control track is searched by the above-mentioned method, the microcomputer 24 reads the information of the disc type recorded on the control track or the maximum address through the signal reading circuit 29, and the gain is obtained according to the information. When the gain of the variable amplifier 26 is switched, the time when the light beam 4 on the disk 1 crosses one track at the time of search and track jump and the light beam 4
After making the correspondence of the moving speed of (1) to (4) appropriate, the search is performed using the speed signal obtained from the time when the light beam 4 on the disk 1 crosses the track. Therefore, the moving speed of the light beam 4 can be detected with high accuracy, and a desired track can be searched stably and at high speed.

The above-mentioned track pitch information is not limited to the control track indicating the type of the disc, but is the largest address among the tracks in which the address numbers are recorded in ascending order in the spiral direction of the disc track. Numbered tracks or tracks with the numbered address numbers recorded in ascending order in the spiral direction of the disc track are recorded on the innermost and outermost tracks that have the smallest address numbers. It is obvious that it is possible to record only the track pitch and use that track.

Next, a third embodiment will be described with reference to FIG. In the figure, 51 is a coefficient switching circuit for changing the amplification factor of the signal of the speed reference generator, the amplitude limit value, the speed descending point during deceleration, and the curve,
In case of analog execution, it is connected to the output side of the speed reference generator, and in case of digital calculation, it is connected to the input side of the speed reference generator to switch the speed reference curve. The other elements are the same as those in the second embodiment except that the variable gain amplifier is deleted.

This embodiment realizes the same effect by switching the coefficient of the speed reference signal instead of changing the gain of the variable gain amplifier of the second embodiment, and is initialized when the disk is switched. Under certain conditions, the switch 33 is set to the high-pass filter 41 side as a speed detector, the control track is searched, and the track pitch is detected by the information of the control track. Then, the coefficient switching circuit is set to the optimum value. , The switch 33 is set to the D / A converter side to perform the search. Unlike the first and second embodiments, in this embodiment, the deceleration point at the time of search can be set in accordance with the track pitch information, so that more stable search can be realized. In this case, it is general to set the deceleration point at the time of search by the number of remaining tracks, but the deceleration distance determined by the number of remaining tracks is also greatly affected by the track pitch, so the deceleration curve is set more strictly. It is set so that the search speed can be further increased.

In this embodiment, the coefficient switching circuit is added to the second embodiment. However, the coefficient switching circuit of this embodiment is applied to the first embodiment in which the speed detector configuration is deleted, or It is also within the scope of the present invention to speed up the search more stably by adjusting the speed detection gain with the variable gain amplifier and determining the deceleration point and the deceleration curve with the coefficient switching circuit.

Next, a fourth embodiment will be described with reference to FIG. The constituent elements shown in the figure are the same as those of the third embodiment except that the D / A converter that outputs the speed across the track is deleted. In this configuration, the photodetector 37 is used for speed detection during search.
The speed detector constituted by the high-pass filter 41 and the like is used, and the position of the light beam is detected by the number of tracks traversed. By this,
The speed detection is no longer affected by the track pitch, but it is affected by the track pitch because the deceleration point and the deceleration curve at the time of search are determined by the track pitch. Therefore, after the information of the control track is read, the deceleration point and deceleration curve of the coefficient switching circuit 51 are set to the optimum values so that the search can be speeded up and stabilized.

The present invention is not limited to the embodiments. For example, in the embodiments, the velocity detector is constructed by using the optical position detector, but the magnetic type utilizing the velocity detection coil and the permanent magnet, the hall element or the like. A position detector may be used. Further, it is also possible to use the speed detector using the speed detection coil as it is as the speed signal, and in the case of the fourth embodiment, when the position detector is not necessary for setting the initial position without mounting the disk. Therefore, it is desirable to use a speed detection coil having high speed detection accuracy as a speed detector.
In the pickup of the embodiment, the light source 3, the photodetector 11 and the like are fixed and the objective lens and the like are placed on the movable mount 13 to reduce the movable mass. It is obvious that it can be applied to an integrated pickup that moves as a unit. Also D /
A converter 25, variable gain amplifier 26, switch 33, operation amplifier 32, speed reference generation circuit 31, counting circuit 30,
It is possible to configure the speed control circuit 34, the switch 35, the tracking control circuit 19, the switch 20, the odd number switching circuit 51, etc. together in one dedicated microcomputer, or to apply the configuration of the present invention to digital control. is there.

Although the speed reference signal curve for track search has been described as a trapezoidal wave profile having a constant speed region and stability being emphasized, a track search device using a triangular wave profile in which constant acceleration and constant deceleration are set. However, it is obvious that the present invention is effective.

Further, although the present embodiment has been described by using the optical disk device, it can be applied to a device such as an optical card having a large number of tracks for recording / reproducing information and recording / reproducing using light. It is also obvious that it is possible.

[0050]

According to the present invention, the sensitivity switching means for switching the sensitivities of the crossing number detecting means and the crossing speed detecting means for detecting the number of tracks and the speed at which the pickup means crosses the tracks, or the speed detecting means of the independent pickup means is provided. When the track pitch is unknown, the speed detector and the reference signal generator are compared, and after the track pitch is determined, the output of the speed detector is switched to the transverse speed detecting means whose sensitivity has been switched. Or a coefficient switching means of the reference signal generator is provided, and the search control of the linear motor is performed by comparing the coefficient switching means and the transverse speed detecting means or by comparing the outputs of the coefficient switching means and the speed detecting means. Configuration,
When searching for the control track where the medium information of the disk was first recorded or the track having the highest address number, the sensitivity switching means is set to the narrowest track pitch or the speed detector Since the output is used for searching, it is possible to stably search for the control track and the track having the highest address number without being affected by the track pitch even when the disc is replaced with a disc having a different track pitch. it can. Also, after searching the control track and reading the information about the disc from the information written in the control track or from the maximum address number and switching the sensitivity of the traverse speed detector to match the disc track pitch, the traverse speed detector The sensitivity of is set to the optimum and the output is used, or the coefficient of the speed reference is set to the optimum to search for the desired track, so that the moving speed of the light beam on the disk is highly accurate. It is possible to detect and search for a desired track at high speed and stably.

Further, before the information of the control track is read by the test search of a fixed number of tracks, the above setting and the pulse width setting of the track jump are set to the optimum values, so that the search can be made stable when the disks are switched. Not only that, by utilizing this function also for stabilization during normal track search, it is possible to realize a track search device that can stably cope with temperature changes, changes over time, and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2A is a diagram of a tracking error signal having a substantially sinusoidal waveform output to the differential amplifier 18. FIG. 2B is a rectangular waveform track obtained by comparing the signals of the differential amplifier 18 by the cross detection circuit 23. Crossing signal illustration

FIG. 3 is a schematic diagram showing a search speed profile of the present invention.

FIG. 4 (C) Waveform diagram of track jump pulse (D) Waveform diagram of tracking error signal at the time of track jump

FIG. 5 is a block diagram showing a second embodiment of the present invention.

FIG. 6 is a block diagram showing a third embodiment of the present invention.

FIG. 7 is a block diagram showing a fourth embodiment of the present invention.

FIG. 8 is a schematic diagram showing a detection principle of a tracking error signal.

FIG. 9 is an example waveform of a track crossing waveform when the track pitch is different.

[Explanation of symbols]

 1 Disc 2 Motor 3 Light Source 9 Converging Lens 13 Frame 14 Linear Motor Coil 15 Tracking Coil 18 Differential Amplifier 19 Tracking Control Circuit 22 Drive Circuit 23 Traverse Detection Circuit 24 Microcomputer 26 Gain Variable Amplifier 30 Counting Circuit 31 Speed Reference Generating Circuit 33 Switch 34 speed control circuit 35 switch 36 drive circuit 37 photodetector 41 high-pass filter 46 light source 48 oscillator circuit 49 jump circuit 50 adder circuit 51 coefficient switching circuit

Claims (15)

[Claims] 1. Pickup means for recording information or reproducing a signal from a record carrier having a track on which the information is recorded, and signal processing means for detecting information from the signal reproduced by the pickup means. Tracking error detecting means for detecting a positional deviation between the reproduction position of the pickup means on the record carrier and the track on the record carrier, and a reproduction position of the pickup means on the record carrier substantially orthogonal to the track direction on the record carrier. First and second moving means for moving in the direction, and the first moving means is driven according to the output of the tracking error detecting means to control so that the reproduction position of the pickup means is always on the track. The control means of No. 1 and the track that the pickup means crosses the track from the output of the tracking error detection means. And a crossing speed detecting means for detecting the speed, a crossing speed detecting means, a sensitivity switching means for switching the sensitivity of the crossing speed detecting means, and a pickup means of the pickup means according to the output of the crossing number detecting means when searching for a desired track. A reference signal generating means for generating a speed reference signal, and the second moving means is controlled by an output obtained by comparing the output of the transverse speed detecting means whose sensitivity is switched by the sensitivity switching means with the output of the reference signal generator. An information track search device characterized by controlling. 2. Pickup means for recording information or reproducing a signal on a record carrier having a track on which the information is recorded, and signal processing means for detecting information from the signal reproduced by the pickup means. Tracking error detecting means for detecting a positional deviation between the reproduction position of the pickup means on the record carrier and the track on the record carrier, and a reproduction position of the pickup means on the record carrier substantially orthogonal to the track direction on the record carrier. First and second moving means for moving in the direction, and the first moving means is driven according to the output of the tracking error detecting means to control so that the reproduction position of the pickup means is always on the track. The control means of No. 1 and the track that the pickup means crosses the track from the output of the tracking error detection means. And a crossing speed detecting means for detecting the speed, a crossing speed detecting means, a sensitivity switching means for switching the sensitivity of the crossing speed detecting means, and a pickup means of the pickup means according to the output of the crossing number detecting means when searching for a desired track. A reference signal generating means for generating a speed reference signal; a speed detecting means for detecting a moving speed of a moving body moved by the second moving means; an output of the traverse speed detecting means and an output of the speed detecting means. An information track search device characterized in that the second moving means is controlled by a switch means for switching and an output comparing the output of the switch means and the output of the reference signal generating means. 3. Pickup means for recording information or reproducing a signal on a record carrier having a track on which the information is recorded, and signal processing means for detecting information from the signal reproduced by the pickup means. Tracking error detecting means for detecting a positional deviation between the reproduction position of the pickup means on the record carrier and the track on the record carrier, and a reproduction position of the pickup means on the record carrier substantially orthogonal to the track direction on the record carrier. First and second moving means for moving in the direction, and the first moving means is driven according to the output of the tracking error detecting means to control so that the reproduction position of the pickup means is always on the track. The control means of No. 1 and the track that the pickup means crosses the track from the output of the tracking error detection means. And a crossing speed detecting means for detecting the speed, a crossing speed detecting means, a reference signal generating means for generating a speed reference signal of the pickup means according to the output of the crossing number detecting means when searching a desired track, and the reference signal. A coefficient switching means for switching the coefficient of the generating means,
An information track searching device, wherein the second moving means is controlled by an output obtained by comparing an output of the traverse speed detecting means and an output of the speed reference generator whose coefficient is switched. 4. Pick-up means for recording information or reproducing a signal from a record carrier having a track on which the information is recorded, and signal processing means for detecting information from the signal reproduced by the pickup means. Tracking error detecting means for detecting a positional deviation between the reproduction position of the pickup means on the record carrier and the track on the record carrier, and a reproduction position of the pickup means on the record carrier substantially orthogonal to the track direction on the record carrier. First and second moving means for moving in the direction, and the first moving means is driven according to the output of the tracking error detecting means to control so that the reproduction position of the pickup means is always on the track. The control means of No. 1 and the track that the pickup means crosses the track from the output of the tracking error detection means. Of the crossing number detecting means for detecting a desired track, a reference signal generating means for generating a speed reference signal of the pickup means according to the output of the crossing number detecting means when searching for a desired track, and a coefficient of the reference signal generating means. Coefficient switching means and speed detection means for detecting the moving speed of the moving body moved by the second moving means are provided, and the output is obtained by comparing the output of the speed detection means with the output of the coefficient switching means. An information track search device characterized by controlling a second moving means. 5. When retrieving a desired track, the first control means is made inoperative, the second control means is made to operate, and the moving speed reference signal of the pickup means is generated from the reference signal generation means, so that the pickup means. 5. The first control means is operated again and the second control means is deactivated when it detects that the vehicle has come on a desired track, and the second control means is deactivated. Information track search device described. 6. A moving speed of the pickup means is controlled by using an output of the speed detecting means when searching a specific track in which the information for discriminating the kind of the record carrier is recorded by changing the record carrier. After the pickup means has moved to the specific track and the information such as the track pitch recorded on the specific track has been detected by the signal processing means, the switch means is switched, and the track is searched by the output of the transverse speed detection means. 3. The information track searching device according to claim 2, wherein the sensitivity of the transverse speed detecting means is switched by the sensitivity switching means in accordance with track pitch information. 7. After the pickup means moves to a specific track and the information such as the track pitch recorded on the specific track is detected by the signal processing means, the sensitivity switching means operates in accordance with the track pitch information. 2. The information track searching device according to claim 1, wherein the sensitivity of the traverse speed detecting means is switched. 8. The coefficient switching means for switching the coefficient of the reference signal generating means after the pickup means has moved to a specific track and the information such as the track pitch recorded on the specific track has been detected by the signal processing means. 5. The information track searching apparatus according to claim 3, wherein the coefficient of the reference signal generating means is switched according to the track pitch information. 9. A search time measuring means for measuring a time required to search for a fixed number of tracks is provided, and after the search for a fixed number of tracks is carried out, the sensitivity is switched according to the output of the search time measuring means. 3. The information track searching device according to claim 1, wherein the sensitivity of the crossing speed detecting means is switched by means. 10. A search time measuring means for measuring a time required to search for a fixed number of tracks, and after performing a search for a fixed number of tracks, coefficient switching according to the output of the search time measuring means. 5. The information track searching device according to claim 3, wherein the means is controlled to switch the coefficient of the reference signal generating means. 11. The sensitivity of the transverse speed detecting means is switched according to the initial setting of the sensitivity switching means to the narrowest pitch expected for the track pitch when the record carrier is replaced. The information track search device according to claim 2. 12. The coefficient of the reference signal generating means is switched according to the initial setting of the coefficient switching means in accordance with the narrowest expected track pitch when the record carrier is replaced. 3 or claim 4
Information track search device described. 13. The information track searching apparatus according to claim 5, wherein a specific track is a control track provided on the record carrier and in which information indicating the type of the record carrier is recorded. 14. The track according to claim 6, wherein the specific track is the track having the largest address number among the tracks on which the address numbers given to the tracks of the record carrier are recorded. 8. The information track search device described in 8. 15. The specific track is a track having the smallest address number among the tracks in which the address numbers assigned to the tracks of the record carrier are recorded. Information truck search device described in any of the above.