JP2806128B2 - Optical tape device and optical tape used in this device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical tape device.

[0002]

2. Description of the Related Art For example, FIG.
FIG. 3 is a diagram showing the configuration of a conventional optical tape device disclosed in Japanese Patent Application Publication No. 3 (1993) -207, in which a signal generating circuit 97 reads a recording signal for recording information and a position signal on the optical tape 72 and reads information recorded on the optical tape 72. A reproduction signal for reading or an erasing signal for erasing information recorded on the optical tape 72 is generated. These signal generation operations are performed by a command or the like from the host system. The signal generated by the signal generation circuit 97 is modulated by the modulation circuit 98, and the output is input to the laser drive circuit 99. The laser 74 is driven by the laser driving circuit 99, and oscillates in response to a command from the signal generating circuit 97, and the light beam 75
Is generated.

[0003] The light beam 75 is controlled to an optimum intensity and duration in accordance with each mode of recording / reproducing / erasing. The light beam 75 is shaped into a parallel beam by a lens 76, further divided into a main beam and two sub-beams by a diffraction grating 73, and then transmitted through a polarizing beam splitter 78 to become linearly polarized light. Then further λ
The light passes through the 板 plate 83, is reflected by the mirror 79, passes through the objective lens 80, and reaches the recording medium of the optical tape 72.

The light beam 75 is directed to a tracking position on the recording medium of the optical tape 72, and is configured to focus on the position by focusing control.
Here, the polarization beam splitter 78 has a function of preventing the light reflected on the optical tape 72 from returning to the laser 74 in combination with the λ / 4 plate 83. Optical tape 7
The reflected light from 2 is transmitted through the λ / 4 plate 83 again, and is converted into a direction of 90 ° linearly polarized light with respect to the time of incidence. Therefore, the reflected light from the optical tape 72 is reflected by the polarization beam splitter 78 in its entire polarization amount.

[0005] Lens 82 and cylindrical lens 8
The main beam for reproduction and focusing transmitted through 4 is polarized to be elliptical and is incident on the detection unit 86 together with the sub beam for tracking. The signal read from the detection unit 86 is demodulated by the demodulation circuit 101 and the reproduction circuit 1
00 reproduces the original signal. Also, the detecting unit 86
Output a tracking error signal, a focus error signal, a speed error signal, and a tape angle error signal.

The actuator 8 moves the objective lens 80 in parallel with the surface of the optical tape 72 in accordance with the tracking error signal by the operation of the tracking control section 96.
1 is driven to perform tracking control. Further, the tape guide 90 which sets the angle of the optical tape 72 with respect to the spot moving direction of the light beam on the optical tape 72 according to the tape angle error θ by the operation of the tape angle control unit 95 moves the tape guide 90 in the width direction of the tape. The motor 93 to be moved is driven to perform optical tape angle control. Further, the pinch roller 9 for moving the optical tape 72 in the longitudinal direction by the operation of the tape speed control unit 94 and the scan speed control unit 102
The speed of the motor 91 for rotating the mirror 2 and the motor 77 for rotating the mirror 79 are controlled, whereby the optical tape speed is controlled in accordance with the speed error signal v.

FIG. 19 is also similar to Japanese Patent Application Laid-Open No. 62-10923.
FIG. 2 is a conceptual diagram illustrating an optical tape device disclosed in Japanese Patent Publication No. 3 (hereinafter, referred to as No. 3), in which an optical tape 72 is mounted in an optical tape device 103. The optical tape 72 is spirally wound around a supply reel and a take-up reel 104, and from these reels, the optical tape 72 is held by a pair of tape guides 90 so as to be in close contact with a rotating drum 85 via rollers 92. . FIG.
(B) is a view of the drum section viewed from the direction of arrow A in FIG. 17 (a). The rotating drum rotates at a speed much higher than the speed of the optical tape 72 sent by the rollers 92 so that the irradiation light from the objective lens 80 moves on the dotted line in the drawing.

FIG. 20 is a view similar to that of Japanese Patent Application Laid-Open No. 62-10923.
FIG. 3 is a diagram showing a recording format of an optical tape disclosed in Japanese Patent Application Laid-Open No. 3 (1993) -207, in which tracking signals SC1 and SC2 are provided at an upper end and a lower end of a recording track of the optical tape 72.
Is written, and tracking is performed based on this signal.

[0009]

In the conventional optical disk device, there is a problem that the total recording capacity in one package is extremely smaller than that of the tape-shaped medium because the surface area of the recording medium involved in recording and reproduction is small. Was. On the other hand, the magnetic tape device also has drawbacks in that recording and reproduction are performed by contact between the magnetic tape and the magnetic head, so that the reliability and durability are poor, and that the magnetic tape device is easily scratched at the time of high-speed search.

Therefore, by forming a sufficiently narrowed light spot on an optical recording medium on an optical tape, and by accurately accessing a portion where the light spot has been signal-recorded at the time of reproduction, a high spot similar to that of an optical disk can be obtained. It was necessary to maintain stable areal recording density. Therefore, means for controlling the focus of the light spot, such as an optical disk, means for controlling the light spot in the tracking direction, and means for moving the tape, such as a magnetic tape device, are required, while maintaining a high surface recording density. It became.

However, in the conventional optical tape device,
Since the means for extracting a tracking error without forming a guide groove for tracking on the optical tape is only the upper end and the lower end of the tape, it is impossible to cope with a track deviation such as a track bend. Is not much different from the tracking means used in a magnetic tape device. For example, it is the same as the area division pilot method used in a DAT (Digital Audio Tape Recorder). In this case, the track pitch is actually 10
It is known that the pitch can be reduced to only about μm. In order to further reduce the pitch to a 1.6 μm pitch comparable to that of an optical disk, the above-described track bending and the like (track deviation in one track) are detected and controlled. There is a need.

Further, in the conventional optical tape device,
Since the recording medium portion of the optical tape is run in contact with a rotating drum or a pinch roller, non-contact recording / reproduction, which is a feature of an optical disk device or the like, cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a non-contact,
And while maintaining the high surface recording density of an optical disc device,
An object of the present invention is to provide an optical tape device that can realize an extremely large-capacity recording and reproducing system by forming an optical recording medium in a tape shape.

[0014]

According to the present invention, in order to realize non-contact recording, optical
The recording medium is deposited on the base film of the tape or
On the side that has been coated, it is necessary to run the optical tape.
The travel system is configured so that the travel pins do not contact
The spot on the optical tape to minimize optical system aberrations.
Round the optical tape in the running direction to scan while holding
A cylindrical traveling guide is provided to flex the metal or plastic member constituting the cylindrical traveling guide to a certain polarity, and at the same time, the optical tape is also made to have the same polarity. The non-contact state is maintained by utilizing the repulsive force of the electric field by charging.

According to the present invention, there is provided an optical tape comprising a reel motor or the like based on a signal obtained by optically detecting a defocus of a non-light spot by a Foucault method, a knife edge method or an astigmatism method for performing focus control. by the winding sent out tape tension by controlling the reel drive means for the variable, giving a reaction force against the electric field of repulsion between the recording medium surface and the cylindrical travel guide optical tape, The focus control is performed by adjusting the distance between the recording medium surface and the cylindrical traveling guide.

According to the present invention, in order to perform focus control, a movable pin is provided which can move its position based on a signal obtained by optically detecting a defocus of a non-light spot by a Foucault method, a knife edge method or an astigmatism method. The tape travel path length can be arbitrarily varied in the tape travel path, and the tape tension is made variable by applying a driving force to the movable pin with a voice coil actuator or a piezoelectric element. Focusing control is performed by giving a reaction force to the repulsive force of the electric field between the traveling guides and changing the distance between the recording medium surface of the optical tape and the cylindrical traveling guide. .

According to the present invention, in order to perform tracking control,
A printable protection film is formed on a recording medium formed on a base film, and a tracking mark is formed on the protection film by a plurality of light spots to be scanned by a light spot in a light scanning direction. When the light spot where laser light emitted from the objective lens is condensed at the time of optical scanning passes through a plurality of tracking marks shifted forward and backward in the tracking direction, The objective lens is moved in the tracking direction so that the amplitude change of a signal obtained by photoelectrically converting the reflected reproduction light amount is controlled so that the light spot traces an optical scanning locus to be scanned.

According to the present invention, in order to perform tracking control,
Form a printable protective film on the recording medium of the base film, and on this protective film, parallel to the light scanning direction,
Using an optical tape on which a slit whose pitch is about 1-2 times the spot diameter focused by the objective lens is printed,
The light beam is divided into multiple beams by a diffraction grating placed in front of the objective lens for focusing the laser beam, and the beams are focused at positions that are shifted back and forth across the light scanning trajectory to be scanned by the light spot. By moving an objective lens or the like in the tracking direction so that the amplitude of a signal obtained by photoelectrically converting the reproduction light amount reflected from the plurality of condensed spots becomes equal, an optical scanning locus that the light spot on the recording medium should always scan Is provided so as to be traced.

According to the present invention, at the time of recording, the frequency of a low-frequency pilot signal included in a recording signal is changed for each scan of a light spot, and at the time of reproduction, a diffraction grating arranged in front of an objective lens is provided. The light beam is divided into a plurality of parts, and the light spot is focused on a track that is shifted forward and backward across the optical scanning trajectory to be scanned, and the reproduced light amount reflected from the plurality of focused spots is photoelectrically converted into a signal. The light spot moving means drives the light spot in the track direction so that the signal amplitudes of the pilot signals included in the light spot are equal to each other, and controls so as to always trace the recorded light spot scanning locus.

[0021]

Cylindrical running guide in DETAILED DESCRIPTION OF THE INVENTION The present invention, together to deflect a spot on the optical tape circularly running direction of the tape light in order to scan while minimizing aberrations of the optical system, the traveling person the cylindrical A non-contact state is maintained by generating a repulsive force due to static electricity between the guide and the optical tape. This allows the optical tape to travel without the medium surface in contact with the travel guides and travel pins of the apparatus. In a general magnetic tape device, it is necessary to cause a magnetic head and a magnetic tape to travel in contact with each other on a rotating drum. However, in the case of an optical tape, it is possible to cause the magnetic tape to float and travel.

In the tension control in the present invention, the tape tension of the optical tape is varied by controlling a reel motor or a movable pin having a variable tape running length based on a focus error detected optically. Perform control.

According to the present invention, in order to perform tracking control, a printable protection film is formed on a recording medium formed on a base film, and tracking marks are formed on the protection film in the optical scanning direction. A plurality of light spots are arranged at positions deviated back and forth across the light scanning locus to be scanned, or on a protective film, the pitch of which is parallel to the light scanning direction and the pitch is 1 to 1 of the spot diameter focused by the objective lens.
Printed versions of slits is about 2-fold, it is possible to perform tracking control by using a San Purusabo or 3-beam method.

According to the present invention, at the time of recording, the frequency of a low-frequency pilot signal included in a recording signal is changed for each one scan of the light spot, and at the time of reproduction, the pilot signal is arranged before the objective lens. The light beam is divided into a plurality of parts by a diffraction grating, and the light spot is focused on tracks that are shifted back and forth across the light scanning trajectory to be scanned, and the reproduction light amount reflected from the plurality of focused spots is photoelectrically converted. The light spot moving means for moving the light spot in the track direction is controlled so that the signal amplitude of the pilot signal included in the obtained signal becomes equal, and control is performed so that the recorded light spot scanning locus is always traced.

[0025]

FIG. 1 is a plan view of an optical tape device according to an embodiment of the first invention. 1 is a supply reel for supplying an optical tape 16, 2 is a take-up reel for winding the optical tape 16, and 3 is a reel. A fixing pin for running the optical tape 16, a tilt pin 4 for moving the optical tape 16 along the tape regulating surface 10, a cassette for housing the optical tape 16, and an objective 6 for condensing the laser light A lens, 7 is a rotating mirror for scanning laser light, 8 is a balancer for adjusting the center of rotation of the rotating system at the center of rotation of the rotating mirror 7, 9 is a motor for generating a driving force for rotating the rotating mirror 7, and 11 is a motor. A half mirror 13 that bends the optical path of the emitted light from the semiconductor laser 12 and the reflected light from the optical tape 16. Cylindrical lens for receiving the detector 14, 15 is an optical head which houses the optical system, 34 is a tape running speed detector.

FIG. 2 is a partially enlarged side view of the traveling system of the optical tape 16 of the present embodiment. Reference numeral 25 denotes a laser beam emitted from the objective lens 6 rotating inside the tape regulating surface on the optical table 16. It is a laser emission window for hitting.

FIG. 3 is a sectional side view of the present embodiment. Reference numeral 19 denotes a reel rotating shaft for driving the supply or take-up reel 2, reference numeral 20 denotes a cassette housing connected to the reel 2 for rotation, and reference numeral 21 denotes a cassette housing. A deck base 22 for supporting the whole, a galvano mirror 22 for moving the light beam in the tracking direction, and a reflecting mirror 23 for bending the optical path of the light beam.

FIG. 4 is a partially enlarged side sectional view showing a part involved in the formation of a light spot according to the present embodiment. 24 is a fan for increasing the air pressure in the optical head, and 26 is an optical tape 1.
An air outlet for maintaining a gap between the tape control surface 6 and the tape regulating surface 10.

FIG. 5 is a plan view showing an embodiment of the second invention, and is a conceptual diagram for explaining floating of the optical tape 16 due to static electricity. FIG. 6 is a circle A portion of a dashed line in FIG. 3 is an enlarged view of a portion of the cylindrical traveling guide.

FIG. 7 is a view showing the structure of the running pin 16 for charging the base film of the optical tape 16 of the present embodiment, wherein 67 is a regulating cap, 68 is a conductive charging ring,
9 is a running pin main body.

FIG. 8 is a view showing one embodiment of the third invention, and is a view showing the tape running speed detector 34 and the optical tape. In the figure, 35 is a linear track in which light and dark slits 70 are formed on the optical tape 16 so that the amount of reflected light changes at equal intervals, 36 is a recording track on which information is recorded, and 37 is a tape traveling speed detector 34 Is a light emitting unit for projecting the light, 38 is a photodetector for receiving the reflected light, and 39 is a condenser lens forming an optical system.

FIG. 9 is a partially enlarged view of the surface of the optical tape 16 of this embodiment. In the figure, reference numeral 71 denotes a sample pit for tracking detection for tracking a light spot on the optical tape.

FIG. 10 is a block circuit diagram of a focus control system for controlling the focus of a light spot according to this embodiment. In the figure, 27 is a focus error signal amplification amplifier, 28
Is a sample-and-hold circuit for holding a focus error signal during a non-scanning period to detect a focus error during a period in which the rotating mirror 7 is scanning on the optical tape 16, and 29 is to maintain stability and quick response of the control system. Low-pass filter constituting a phase lead filter of
Reference numeral 1 denotes a drive circuit for driving a supply and take-up reel motor. 32 is a subtractor for comparing with a reference tension amount and calculating a tension error;
Is an adder for adding the correction tension amount to the take-up reel.

FIG. 11 is a block circuit diagram of a tracking control system for performing tracking control according to the present embodiment. In the figure, 40 is a tracking sensor amplifier for detecting the amount of light reflected from the optical tape 16, and 41 is an F / V for converting the output of the tape running speed detector into a voltage to obtain a voltage proportional to the tape speed. Converter, 42
Is a frequency divider for dividing the output of the tape running speed detector, 43 is a phase comparing circuit for comparing the phase of the output of the frequency divider 42 with the reference signal and taking out a tape running phase error,
44, a low-pass filter for ensuring stability and quick response of the phase control system; 47, a comparator for detecting sample pits; 48, a pattern matching circuit for matching the pattern of the sample pits; A sample-and-hold circuit for sampling, 50 is an operation amplifier for obtaining a track error signal, 51 is a phase compensation circuit, and 52 is a drive circuit for a tracking actuator.

FIG. 12 is a block circuit diagram of a tracking control system for performing tracking control without using the tape running speed detector 34 in this embodiment. In the figure, 53 is an equivalent circuit simulating the frequency characteristics of the actuator, and 54 is a phase lead compensation circuit.

FIG. 13 is a block circuit diagram of a tracking control system of the optical tape device at the time of special reproduction according to this embodiment. In the figure, 55 is a hysteresis comparator for shaping the waveform of a pulse train of a linear track, which is the output of the tape running speed detector, 56 is a sawtooth wave generating circuit for generating a sawtooth wave based on the pulse train, and 57 is for adding to the tracking control signal Is an adder.

FIG. 14 is a timing chart for explaining a method of generating a track error from a sample pit in the embodiment of FIG. FIG. 15 is a block circuit diagram of the pattern matching and track error generator in FIG. In the figure, 58 is a PLL circuit for generating a reference clock from sample pits, 59 is a data latch circuit for storing the information of the sample pits in time series, and 60 is a sample pulse generating circuit for sampling the amount of reflected light in the sample pits , 61 is a pattern matching circuit, 62 is a flip-flop circuit for determining the polarity of a sample and hold circuit and sampling a track error signal, 63 is a short pulse generation circuit, 64 is a polarity switch, and 65 is a track error sample and hold circuit. is there.

FIG. 16 is a diagram for explaining tracking by a pilot signal included in a recording signal according to the present invention.
FIG. 3 is a diagram showing a recording track pattern.

FIG. 17 is a block diagram of a tracking control system for performing tracking by a pilot signal included in the recording signal of the embodiment of FIG. In the figure,
105 is a photodetector for receiving the diffracted light, 106 is a polarity inversion switch for inverting the polarity every rotation of the rotating mirror 7, 107 is a bandpass filter for extracting a pilot signal, and 110 is a track error signal. An operation amplifier 109 for obtaining the control circuit is a control circuit of the rotating mirror motor.

Next, the operation will be described. In an optical tape device, it is required to achieve both long-time recording and large capacity in a magnetic tape device and high density, non-contact and high reliability in an optical disk device. Therefore, in the present embodiment, the light spot is narrowed down by a lens using the current semiconductor laser light to form a light spot of about 1 μm in the case of a laser having a wavelength of 720 nm, for example. The tape running system is configured such that the medium surface comes.

In order to maintain a light spot as small as 1 μm, the amount of optical light scanning must be reduced to some extent. For example, in an optical disk device, the amount of movement of an objective lens is limited to several hundred μm. this is,
If the optical scanning amount is larger than the above, the incident angle of the objective lens becomes large, the optical aberration increases, and a good optical system cannot be formed. However, if the size of the light spot diameter can be allowed to some extent, optical scanning can be performed without using a very complicated mechanism by using an fθ lens or the like used in a laser printer or the like.

However, if a certain light spot diameter is allowed (for example, several tens of μm) as described above, it becomes impossible to bring the feature of high-density recording realized by an optical disk or the like to an optical tape device. In addition, a tape running system is required to reduce the influence of optical aberration to some extent during light spot scanning. Also, the optical tape is different from the magnetic tape in that the optical head (magnetic head in the case of magnetic tape)
Since there is no need to contact the recording medium surface with the tape running mechanism, there is also a need for a tape running system in which the recording medium surface does not contact.

FIG. 1 is a view showing a running system of the optical tape 16. The optical tape 16 accommodated in the reels 1 and 2 in the cassette 5 has a substrate (binder) formed on the back side of the recording medium surface. The running pins 3 and 4 are brought into contact with each other and pulled out of the cassette 5. Next, the drawn optical tape 16 is a non-rotating cylindrical running guide (tape regulating surface) 1.
Wound around 0. This cylindrical traveling guide 10 includes:
As shown in FIG. 2, a laser emission window 25 for passing a laser beam is opened, and a laser is emitted from the laser emission window 25 toward the medium surface of the optical tape 16. Emission window 25 for the laser
Is opened obliquely with respect to the optical tape 16 as shown in FIG. 2 so that the recording track trajectory is helically scanned on the optical tape 16. This is to increase the bit rate in the linear direction by performing helical scan recording on the optical tape 16.

Naturally, in order to obtain a large optical scanning angle while minimizing the aberration of the optical system, it is necessary to perform optical scanning with the rotating mirror 7 or the galvanometer mirror 22 or the like. In this example, the rotating mirror 7 is rotated. Although it is necessary, the rotating surface of the rotating mirror 7 at this time is slightly inclined with respect to the traveling direction of the optical tape 16, and the laser emission window 25 opened in the cylindrical traveling guide 10 is also inclined.

In particular, since the optical tape 16 has a light spot diameter of about 1 μm when a semiconductor laser is used, it is impossible to increase the linear density in comparison with magnetic recording. Therefore, it is necessary to increase the rotation speed of the rotating mirror 7 to increase the bit rate in the linear direction, to arrange a plurality of semiconductor lasers, or to make the semiconductor laser 12 in the drawing a semiconductor laser 12 capable of emitting multiple beams. There is.

In particular, when an analog signal is recorded, the continuity of the signal in one track is important. Therefore, it is necessary to increase the amount of information per track by using a helical scan as the recording track. However, when recording / reproducing a digital signal, the continuity of the signal in one track is not so important. Therefore, even if the angle between the rotating mirror 7 and the recording track with respect to the traveling direction of the optical tape 16 is slightly large. I can't tell. In this case, although the amount of information per recording track decreases, the bit rate can be increased by increasing the rotation speed of the rotating mirror 7.

As described above, with respect to the optical tape 16,
The recording bit rate can be increased by performing helical scan recording like a magnetic tape, but when performing optical scanning, it is necessary to minimize the aberration of the optical system as much as possible.
Therefore, it is necessary to keep the distance between the objective lens 6 and the optical tape 16 to be recorded to some extent constant. For this purpose, it is necessary to bend the optical tape 16 circularly with respect to the rotating objective lens 6.
Is required.

However, the cylindrical traveling guide 10 described above
Are the traveling pins 3 necessary for loading the optical tape 16.
Unlike 4 and 4, it exists on the optical tape recording surface side,
It may be a major cause of loss of recording media and occurrence of defects due to contact running. Further, since the optical tape 16 is recorded at a certain focal distance from the objective lens 6, it is desirable to run the optical tape 16 in a non-contact manner rather than in a contact manner.

For this purpose, in this embodiment, as shown in FIG. 4, the inside of the cylindrical traveling guide 10 is sealed at the portion other than the contact portion with the optical tape and the air injection port. Laser emission window 2 by increasing air pressure
Air is ejected from the nozzle 5 to prevent the optical tape 16 from contacting the cylindrical travel guide 10. Further, on the traveling side of the optical tape 16 of the cylindrical traveling guide 10,
In addition to the laser emission window 25, a minute air blowing hole 2
By opening 6, the entire optical tape 16 can be uniformly floated from the cylindrical traveling guide 10.

At this time, a motor 9 for driving the rotating mirror 7 necessary for optical scanning is provided with a fan 24 for increasing the air pressure in the cylindrical traveling guide 10, and a hole along the rotation axis of the motor 9 is provided with an air intake port. By doing so, the air levitation system can be easily realized. Further, in this case, since the amount of inertia of the rotating portion is only in the peripheral portion of the rotating mirror 7, the amount of inertia of the rotating system is small, and the rotation control system is damped by attaching the fan 24, so that In addition to improving the stability, it is also possible to reduce uneven rotation caused by increasing the control gain.

FIG. 5 shows an embodiment of the second invention.
Uses a repulsive force using static electricity. In this case, the cylindrical traveling guide 10 is charged to a certain polarity, and at the same time, the constituent parts of the base film forming the optical tape 16 or the film-shaped optical tape 16 formed to be charged to static electricity are combined with the cylindrical traveling guide 10. It is charged to the same polarity. Naturally, the charged portion is charged to a high voltage, and is insulated from the deck base 21 and the like. The charging of the optical tape 16 is performed, for example, by charging the base film of the optical tape 16 by applying a high voltage to the two running pins 3 and 4 necessary for extracting the tape during loading. The configuration of the traveling pins 4 for charging the optical tape 16 is shown in FIG. 7. In the drawing, the optical tape 16 is charged by the charging ring 68 and the traveling pin body 69 is made of an insulating material. It can be insulated from the base 21 and the like.

At this time, since the base film of the optical tape 16 and the cylindrical traveling guide 10 are charged to the same polarity,
A repulsive force is generated by static electricity, and non-contact traveling is enabled.

The cylindrical traveling guide 10 for traveling the optical tape 16 in a non-contact manner as described above is disposed in a cassette 5 for accommodating the optical tape as shown in FIG. When the tape runs, the recording surface side of the cylindrical running guide 10 is housed. In the cassette 5, the optical tape 1 is loaded when loading.
Notch 5 for passing the movable running pin 4 for pulling out 6
1 is provided to reduce the travel distance of the traveling pin 4 during loading.

Next, the focus control system will be described. The depth of focus of the condensed spot using the semiconductor laser 12 depends on the wavelength of the semiconductor laser 12 and the NA of the objective lens 6.
Is generally about 1 μm. Therefore, if the accuracy of the cylindrical tape running guide 10 is ± 1 μm or less with respect to a true circle with respect to the rotation center of the reflection mirror 7, the recording surface of the optical tape 16 can be adjusted within the focal depth only by the mechanical accuracy of the cylindrical guide 10. It is possible to maintain

However, since the accuracy of the cylindrical travel guide 10 is generally about 1 μm, it is necessary to perform focus control by some means. Therefore, in this embodiment, the optical tape 1 is used as a focus error signal detecting means.
Using the reflected light from the light source 6 to convert the output of the photodetector from current to voltage using the critical aberration method, the Foucault method, or the knife edge method using a cylindrical lens 13 used in an optical disk recorder or the like. To measure the distance between the optical tape 16 and the objective lens 10, and take out this as a voltage signal.

For example, in the critical aberration method, a cylindrical lens 13 is used to elliptically polarize the position deviated from the focal point to the near and far directions on the detector 14 at right angles on the detector 14 and divided into four parts. By taking the differential between the diagonal outputs of the detectors, it is possible to electrically extract the focus error signal.

In this embodiment, it is considered that the accuracy of the above-mentioned cylindrical traveling guide 10 with respect to a perfect circle is about 1 μm, though it depends on the machining accuracy. In this case, it is necessary to perform the focus control, but since a large operation amount is not required, the air floating between the optical tape 16 and the cylindrical tape running guide 10 is performed by performing the tension control by the reel motors 1 and 2. The focus control can also be performed by keeping the balance of the force against the repulsive force of force or static electricity and controlling the amount of tension.

The focus control by the tension control shown in FIG. 10 can be controlled only in a frequency region near DC, but if the deviation from the roundness of the cylindrical traveling guide 10 is about 1 μm, there is a problem. Absent. That is, since the focus error due to the movement of the light spot on the optical tape 16 by the light scanning of the rotating mirror 7 is within 1 μm, controlling only the DC focus shift always keeps the optical tape 16 within the focal depth of the light spot. Can be controlled to exist.

Such a tension control system amplifies a signal detected based on the above-described optical focus detection method to secure a low-frequency gain of the control system, and performs phase compensation by a phase lead filter 29 to control the tension. Ensure quick response and stability of the system. However, the phase lead compensation is required when the control band is set in a frequency band in which the secondary delay characteristic of the current-phase transfer characteristic of the motor is set.

Here, the transfer characteristic of a general motor varies depending on the amount of moment of inertia of the motor, but the cut-off frequency at which the secondary delay characteristic of the motor starts is generally between several tens mHz and several Hz. Therefore, in order to secure a control band of about several Hz to several tens Hz, it is necessary to perform advance compensation in the positioning control system. However, if the focus control system can detect the moving speed of the control target (in this case, the optical tape), the above-described phase lead compensation need not be performed, and the speed control system and the phase (rotation phase of the reel motor) are controlled. By adjusting the gain ratio with the system, stability and quick response can be ensured.

Such a method of varying the tension force of the optical tape is, in addition to the above-described method using a reel motor, a tape necessary for pulling out the tape at the time of tape loading and winding the tape around the cylindrical traveling guide 10. By mounting an actuator on the pin 3 or 4 and driving the actuator minutely, the tension force can be minutely varied and controlled. In this case, if the movable traveling pin can be configured to be lightweight, a high control band can be obtained, and it is possible to follow the focus fluctuation accompanying the movement of the light spot. Further, by configuring the cylindrical traveling guide 10 itself so as to be closer to or farther from the optical tape 16, the same effect as the variable tension amount by the reel motor can be realized.

The case where the deviation from the true circle of the cylindrical traveling guide 10 is within 1 μm has been described above.
If it is more than m, it is necessary to construct a high-band focus control system by mounting an actuator capable of moving the objective lens 6 in the cylindrical traveling guide 10 in the focus direction. In this case, the focus actuator to be controlled can be configured to be extremely light in weight as compared with the reel motor, so that the control band can be increased. Therefore, the focus actuator is generated when the light spot on the optical tape moves due to the optical scanning. It is possible to follow a deviation of 1 μm or more caused by the processing accuracy of the cylindrical traveling guide 10.

Even in this case, in the low-frequency region including the direct current component in the focus control system, the tension control system using the above-described reel motor or movable traveling pin is shared, and the actuator for moving the objective lens actuator in the high-frequency region is used. The feedback control constitutes a focus control system. At this time, by increasing the open loop gain of the control system in the low frequency range of the focus control system that moves the objective lens as compared with the tension control system, the tension control system can share the frequency in the low frequency range. At this time, the focus control by the tension control can be performed by rotating both the supply reel and the take-up reel in a direction in which the tension is loosened or in a direction in which the tension is tight. , And the tension can be varied by controlling the other reel motor.

Next, the tracking control system will be described. In an optical tape device, the light spot diameter is 1
Since it is about μm, it is possible to increase the track density instead of the linear density as compared with the magnetic tape device. For this purpose, it is necessary to configure a tracking control system.

FIG. 11 is a block circuit diagram of a tracking control system in the present embodiment. The tracking control of the optical tape 16 can be performed by slightly moving the objective lens 6 in the tracking direction by an actuator. Since the dynamic range of the optical tape 16 is small, the optical tape 16 itself needs to run stably at a constant speed. Therefore, the light / dark slit 41 printed on the lower end of the optical tape 16 shown in FIG. 9 is detected by the tape running speed detector 34 shown in FIG. 8 and converted into an electric signal as a pulse train. The traveling speed of the optical tape 16 is controlled so that the tape traveling speed becomes constant by feeding back to the drive motors of the reels 1 and 2 via the reel motor drive circuits 30 and 31 based on the converted tape traveling speed detection signal. You.

In the above-described tape traveling speed detector 34, as shown in FIG. 8, bright and dark slits 70 are printed on the optical tape 16 by the light emitting portion 37 and the lens 39 for condensing the light from the light emitting portion 37. The light is applied to the linear track 35, and the light reflected by the optical tape 16 is collected by the photodetector 38 via the condenser lens 39, so that the bright and dark slits 70 can be detected. At this time, the interval between the light and dark slits 70 may be sufficiently larger than the recording track pitch of the optical tape 16, but in this case, it is necessary to set the interval so that the light emitting unit 37 can sufficiently detect it.

At this time, as shown in the figure, the pulse train output from the tape running speed detector 34 is frequency-divided, the phase is compared with the reference signal, and based on the result, the phase control is performed simultaneously with the speed control. Thus, the running speed deviation of the optical tape 16 can be made closer to zero. As described above, the actuator for driving the objective lens 6 by keeping the running speed of the optical tape 16 constant and further taking the reference of the rotation phase of the rotating mirror 7 from the reference signal serving as the reference for comparing the rotation phases of the drive motors of the reels 1 and 2. Alternatively, the galvanomirror 22 that moves the light beam in the tracking direction only needs to follow a slight track bend of a recording track formed on the optical tape 16, and extremely reduces the dynamic range of the objective lens 6 or the galvanomirror 22. I can do it. This corresponds to a smaller optical aberration.

As described above, the rotation control system of the rotating mirror 7 may use the same signal as the reference signal of the phase control of the tape running control system as the phase control reference signal of the rotation control system of the rotating mirror 7. A pulse train reproduced by the tape traveling speed detector 34 from the light and dark slits 70 of the linear track 35 of the optical tape 16 may be used as a phase control reference signal of the rotation control system.

The tracking control by the objective lens actuator or the galvanomirror 22 is performed by the optical tape 16.
When a tracking guide groove having a depth of about 1/4 of the wavelength of a laser beam used for recording / reproduction is formed, a three-beam method or a push beam method generally used for an optical disc is used. Tracking can be performed using a pull method.

However, in general, the flexible binder (film base) of the optical tape 16 has
Since it is extremely difficult to uniformly form grooves having a pitch of several μm and a depth of about ４ of the laser wavelength, in this embodiment, the printing technique is used to obtain the reflectance as shown in FIG. By disposing different sample pits 71 by a half pitch in the tracking direction back and forth, and by arranging the sample pits before and after the time relative to the scanning of the light spot, the sample pits 71 obtained by time division can be used. The control system is configured by moving the light spot in the tracking direction so that the change in the amount of reflected light is constant with respect to the preceding and following sample pits 71.

The sample pits 40 correspond to the optical tape 16
Printing such that the reflectivity changes (for example, the printed portion absorbs laser light of that wavelength) on a protective film formed on the recording surface side of the laser light, or on a film that easily passes laser light to be used. It is possible to easily form the sample pits 71 in advance by applying such printing. If the intervals between the sample pits 71 are appropriately determined based on the track pitch amount, the angle of the helical scan track, and the like, the sample pits 71 are arranged at equal intervals on the optical tape 16 as shown in FIG. When creating the tape 16, it is very convenient.

In the tracking servo circuit using the sample pits 71, first, the interval between the sample pits 40,
The length of the sample pits 40 is set to a specific pattern, and pattern matching is performed by a pattern matching circuit 48 for detecting this specific pattern during reproduction or during sample pit reproduction during recording. It is possible to determine whether the change in the amount of reflected light is the sample pit 71 before or after, a defect due to a scratch on the medium, or a signal recorded by a punching method such as write-once recording. is there.

In this way, the sample pits 7 before and after
The tracking error can be obtained by reading out the change in the amount of reflected light due to 1 and sampling and holding each of them by the sample and hold circuit 49, and then taking the difference. The tracking error thus obtained is amplified in order to obtain a low-frequency gain of the servo system, and is subjected to a phase compensation circuit 51 (generally, lead compensation) in order to satisfy the stability and responsiveness of the control system. After the passage, the objective lens actuator or the galvanomirror 22 is driven by the actuator drive circuit 52.

In the above description, the running speed control in the running of the optical tape is performed by the running speed detector 34, the tracking control is performed by the sample pits 71 on the tape 16, and each is made non-interfering with each other. Although the system configuration has been described, in some cases, even without the tape running speed detector 34, the tape running is realized by feeding back the low frequency component of the tracking error obtained from the sample pit 71 to the drive motors of the reels 1 and 2. It is possible to

In this case, since the control system of the reel motor and the control system of the tracking actuator or the galvanometer mirror 22 interfere with each other, as shown in FIG. An equivalent circuit 53 simulating the actuator or galvanomirror 22 is arranged, and a phase lead compensating circuit 54 is arranged. The stability of the reel motor control system is satisfied by using the input signal of the reel motor control system as the drive voltage or drive current of the actuator. Can be done.
Such a system is generally called a two-stage coupling system, and can be realized by performing the above-described compensation.

In the special reproduction, that is, when the optical tape 16 is reproduced at a different speed, the scanning locus of the reproduction light spot is shifted from the recording track as shown in FIG. If the reproduction speed is an integral multiple of the speed at the time of normal recording, the track error at this time becomes a sawtooth waveform, and therefore, a sawtooth wave generating circuit 56 that generates a sawtooth wave by a pulse train corresponding to the tape speed of the tape running speed detector. If this output is added to the drive signal, control can be performed stably with a small track deviation.

In the tracking operation using the sample pits 71 as described above, pattern matching is performed based on the principle shown in FIGS. The change in the amount of reflected light due to the sample pit 71 is first determined by the comparator 47.
The reference clock is generated by the PLL circuit 58 at the same time. Based on the reference clock and the output of the comparator 47, the sample pulse generation circuit 6
The sample pulses generated at 0 are sequentially and repeatedly stored in the two sample hold circuits 49 to store the reflected light amounts at the sample pits in FIG. Here, if the pattern of the output of the comparator 47 is as shown in FIG.
If 3T-2T (T is the reference clock length), the pattern matching circuit 61 outputs, so the output of the two sample hold circuits 49 immediately before the output of the first sample pit 71 is changed to + After the polarity is switched so that the signal is input to the sampler, the sample and hold is performed again by the sample and hold circuit 65 to obtain a track error.

As a means for tracking, FIG.
Pilot signal methods such as those shown in 6 and 17 are also conceivable. At the time of recording, the frequency of the low frequency pilot signal included in the recording signal on the optical tape 16 is
As shown in FIG. 16, the light beam is changed every two tracks, and at the time of reproduction, the light beam is divided into a plurality of light beams by the diffraction grating 108 disposed in front of the objective lens. In a right-angle tracking direction, the light spot is focused on a track that is shifted back and forth across an optical scanning locus to be scanned. Further, the reproduction light amount reflected from the plurality of condensed spots is photoelectrically converted, and the light spot is converted by the compensation circuit 51 so that the signal amplitude of the pilot signal included in the signal extracted by the band-pass filter 107 becomes equal. By driving the actuator drive circuit 52 that moves in the track direction, it is also possible to perform control so that the recorded light spot scanning locus is always traced. At this time, since the polarity of the tracking error is inverted every rotation of the rotating mirror 7, the polarity is changed by the polarity inversion switch 106 based on the rotation phase signal.

[0079]

The cylindrical traveling guide according to the present invention scans the optical tape while bending the optical tape in the traveling direction while minimizing the aberration of the optical system of the light spot on the optical tape. Even with respect to the scanning amount, the aberration of the optical system is reduced.

[0080] Also, it allowed rise to electrostatic force of repulsion between the upper SL running guide and optical tape, since to keep a non-contact state, it is possible to the optical disk apparatus as well as non-contact recording and reproduction, an optical tape Can travel without contact of the medium surface with a travel guide or a travel pin of the apparatus.

Further, the focus control device by optical tape tension control according to the present invention controls the reel motor or the movable traveling pin capable of varying the tape traveling length based on the optically detected focus error, thereby controlling the tape of the optical tape. By changing the tension, focus control became possible without using a focus actuator that moves a new objective lens.

In the tracking control according to the present invention, a plurality of tracking marks are scanned in a light scanning direction by a light spot on a protective film printable on a recording medium formed on a base film. Arrange the light scanning trajectory at positions shifted back and forth, or
A light / dark slit whose pitch is about 1 to 2 times the spot diameter focused by an objective lens is printed on a linear track formed on an optical tape, and based on a signal which detects transmitted light or opposite light of the light / dark slit. Tracking control can be performed by using a tracking servo or a three-beam method that can follow a track bend, and a stable tape can be obtained by using a reel motor without using a pinch roller that sandwiches the tape. Running is now possible.

According to the present invention, the frequency of the low-frequency pilot signal included in the recording signal is changed for each scanning of the light spot at the time of recording, and is arranged before the objective lens at the time of reproduction. The light beam is divided into a plurality of parts by the diffraction grating, and the divided light spots are condensed on tracks that are shifted back and forth with respect to the optical scanning locus to be scanned, and are reflected from the plurality of condensed spots. The light spot moving means for moving the light spot in the track direction is driven so that the signal amplitude of the pilot signal included in the signal obtained by photoelectrically converting the reproduced light amount is traced along the light spot scanning locus which is always recorded. This makes it possible to perform tracking during reproduction without preparing information for tracking on an optical tape in advance.

[Brief description of the drawings]

FIG. 1 is a plan view showing an optical tape device according to an embodiment of the first invention.

FIG. 2 is a partially enlarged side view of a running system of the optical tape of the embodiment.

FIG. 3 is a side sectional view of this embodiment.

FIG. 4 is a partially enlarged side sectional view showing a part involved in light spot formation in this embodiment.

FIG. 5 is a plan view of an embodiment of the second invention.

FIG. 6 is an enlarged view of a portion indicated by a broken line circle A in FIG. 5 of this embodiment.

FIG. 7 is a view showing a structure of a traveling pin for charging a base film of the optical tape of this embodiment.

FIG. 8 is a diagram showing a configuration of an optical tape of this embodiment and a configuration of a tape traveling speed detector.

FIG. 9 is a partially enlarged view of the surface of the optical tape of this embodiment.

FIG. 10 is a block circuit diagram of a focus control system for performing focus control of a light spot according to the embodiment.

FIG. 11 is a block circuit diagram of a tracking control system of this embodiment.

FIG. 12 is a block circuit diagram of a tracking control system for performing tracking control without using a tape running speed detector in this embodiment.

FIG. 13 is a block circuit diagram of a tracking control system of the optical tape device during special reproduction according to the embodiment.

FIG. 14 is a timing chart for explaining a method of generating a track error from a sample pit in the embodiment of FIG. 11;

FIG. 15 is a block circuit diagram of a pattern matching and track error generator in the embodiment of FIG. 11;

FIG. 16 is a diagram showing a recording track pattern for performing tracking by a pilot signal included in a recording signal according to the present invention.

FIG. 17 is a block circuit diagram of a tracking control system for performing the operation.

FIG. 18 is a block circuit diagram showing a configuration of a conventional optical tape device.

FIG. 19 is a diagram showing a configuration of a conventional optical tape device.

FIG. 20 is a diagram showing a recording format of a conventional optical tape.

[Explanation of symbols]

 Reference Signs List 1 supply reel 2 take-up reel 3 fixing pin 4 inclined pin 5 cassette 6 objective lens 7 rotating mirror 9 motor 10 cylindrical traveling guide 11 half mirror 13 cylindrical lens 15 optical head 21 deck base 22 galvanometer mirror 23 reflection mirror 24 fan 25 laser Emission window 26 Air outlet 34 Tape running speed detector 35 Linear track 36 Recording track 37 Light emitting unit 38 Light detector 39 Condensing lens 41 F / V converter 42 Frequency divider 43 Phase comparison circuit 44 Low pass filter 47 Comparator 48 pattern Matching circuit 49 Sample hold circuit 50 Differential amplifier 51 Phase compensation circuit 52 Actuator drive circuit 53 Equivalent circuit simulating frequency characteristics of actuator 54 Lead compensation circuit 55 Hysteresis Comparator 56 Sawtooth wave generating circuit 57 Adder 58 PLL circuit 59 Data latch circuit 60 Sample pulse generating circuit 61 Pattern matching circuit 62 Flip-flop circuit 64 Polarity switching switch 65 Sample hold circuit 67 Restriction cap 68 Conductive charging ring 69 Running pin body 70 Bright / dark slit 71 Sample pit 105 Photodetector 106 Polarity inversion switch 107 Bandpass filter 110 Differential amplifier 109 Rotating mirror motor control circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-171442 (JP, A) JP-A-2-218031 (JP, A) JP-A-2-24862 (JP, A) JP-A-3-2 119552 (JP, A) JP-A-3-157855 (JP, A) JP-A-61-273750 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 15/61 G11B 7 / 00 G11B 7/135 G11B 7/24 571

Claims (11)

(57) [Claims] A reflection mirror rotatable by a motor;
Emit laser light with objective lens connected to the mirror
And an optical system for receiving reflected light.
Curve circularly in the row direction and reflect the mirror at the center of the circle.
Bend the laser beam with the
Rotates at an angle, reflects laser light, and stores information on tape media.
In the optical tape device for recording and reproducing information, the objective lens
The focal point where the light emitted from
Cylindrical or having a curved surface containing the trajectory to be scanned
Consists of a semi-cylindrical or cylindrical part
Tape running surface with window formed at the exit part of the
Having a charge on the metal surface constituting the tape running surface.
The base film of the running tape
By charging with the same polarity as the running surface,
Creates a space due to the repulsion of the electric field between
An optical tape device characterized by maintaining a state. 2. For winding or pulling out a tape
And a running pin for running the tape
Object lens having a tape running system and connected to the mirror
And optics for emitting laser light and receiving reflected light
A focusing system for collecting the light emitted from the objective lens.
A point whose trajectory includes a trajectory scanned by the reflecting mirror
Cylindrical, semi-cylindrical, or cylindrical
Running on the tape running surface
Air flow between the running tape and the running surface,
Keep the contact state, or
The focal point where the emitted light converges is scanned by the reflecting mirror.
Or semi-cylindrical with a curved surface containing the trajectory
Or a tape running surface composed of a cylindrical part
The metal surface constituting the tape running surface
Or the surface of the running tape
Charge the base film with the same polarity as the tape running surface
By the repulsion of the electric field between the running surface and
For optical tape running system that creates space and maintains non-contact state
The tape take-up reel or the drawer
Control each or both of the
Light spot emitted from the objective lens
Focus control so that the light is always focused on the tape media surface.
An optical tape device. 3. An objective lens according to claim 1, wherein
The amount of defocus between the light spot and the tape medium
Compared to the amount of defocus in the reflected optical path from the
For example, a cylindrical lens whose elliptical polarization direction changes
And a plurality of divided optical detectors for detecting the elliptically polarized light direction.
Detected by the detector and focus on the output of the photodetector
3. The optical tape device according to claim 2, wherein the optical tape device is controlled.
Place. 4. Winding or pulling out a tape
And a running pin for running the tape
Object lens having a tape running system and connected to the mirror
And optics for emitting laser light and receiving reflected light
A focusing system for collecting the light emitted from the objective lens.
A point whose trajectory includes a trajectory scanned by the reflecting mirror
Cylindrical, semi-cylindrical, or cylindrical
Running on the tape running surface
Air flow between the running tape and the running surface,
Keep the contact state, or
The focal point where the emitted light converges is scanned by the reflecting mirror.
Or semi-cylindrical with a curved surface containing the trajectory
Or a tape running surface composed of a cylindrical part
The metal surface constituting the tape running surface
Or the surface of the running tape
Charge the base film with the same polarity as the tape running surface
By the repulsion of the electric field between the running surface and
For optical tape running system that creates space and maintains non-contact state
The tape from the take-up reel to the feed reel
Movable running that can change the length and can be changed arbitrarily
The row pins are arranged and the movable
The optical tension focused on the tape is varied by changing the tension.
Optical tape device characterized by controlling the focus of the pot
Place. 5. An irregular shape formed on a tape-shaped medium.
Pit or reflectivity change due to phase change of recording material
For recording / reproducing or magneto-optical recording / reproducing
Laser light on a tape-shaped recording medium with an objective lens
A part of an optical recording tape that condenses and records and reproduces signals
Part that does not transmit light in a slit shape that is continuous in the loop running direction
Form a part that transmits light and light, and
Transmitting or reflecting light and receiving it with a photodetector
The running speed of the optical tape is detected by detecting the running speed of the tape.
An optical tape device characterized by controlling the following. 6. An uneven shape formed on a tape-like medium.
Pit or reflectivity change due to phase change of recording material
For recording / reproducing or magneto-optical recording / reproducing
Laser light on a tape-shaped recording medium with an objective lens
A part of an optical recording tape that condenses and records and reproduces signals
Part that does not transmit light in a slit shape that is continuous in the loop running direction
Form a part that transmits light and light, and
When transmitting or reflecting light and receiving it with a photodetector,
The same pitch as the above slit between the light emitting part and the light detector
Tape running by configuring an optical slit composed of
6. The optical tape according to claim 5, wherein the speed is detected.
Device. 7. For winding or pulling out a tape
And a running pin for running the tape
It has a tape running system and is located on the side that comes into contact with the running pin.
To form a base film, and sandwich the base film
Uneven shape formed on the side opposite to the running pin
Pit or reflectivity change due to phase change of recording material
For recording / reproducing or magneto-optical recording / reproducing
The laser light is applied to the tape-shaped recording medium by the objective lens.
Optical recording tape for recording and reproducing signals
And the other side of the recording medium opposite to the base film.
A printable protective film.
Light tape. 8. A base film, and the base film
A recording medium formed on the recording medium and printing on the recording medium
After the film has been formed, the unprinted part
Laser beam for recording and reproduction
The part printed on the media side of
The protective film is constructed so as not to transmit laser light.
One tracking mark in the optical scanning direction
8. The method according to claim 7, wherein a plurality of the elements are arranged.
Light tape. 9. A base film, and the base film
A recording medium formed on the recording medium and printing on the recording medium
Form a protective film that can be
Laser beam for recording and reproduction
Recording / reproducing level in the portion printed on the medium side of
The protective film
At a pitch parallel to the light scanning direction and
Into a slit that is about 1-2 times the spot diameter
8. The optical tape according to claim 7, wherein the optical tape is printed.
H. 10. A tape-like base film, and said tape
A recording medium formed on a base film, and the recording medium
Form a printable protective film on the body and printed
Protects the recording / reproducing laser beam from passing through
In the area printed on the media side of the film,
It is configured so that the laser beam for recording and reproduction is not
Optical scanning of tracking marks on protective film
Tracks arranged in multiple directions and perpendicular to the optical scanning direction
In the scanning direction, the light scanning trajectory to be scanned by the light spot
At the position shifted back and forth between
In an optical tape formed at a position where it does not pass,
The light spot where the laser light emitted from the laser converges is
In the above tracking direction, a plurality of
The amount of reproduced light reflected when passing through the racking mark
So that the amplitude change of the signal obtained by photoelectrically converting
Lens or laser configured in front of objective lens
By moving the light reflector in the tracking direction,
The optical scanning locus to be scanned by the light spot on the recording medium
Control to trace the pre-recorded track
Characteristic optical tape device. 11. A tape-like base film, comprising:
A recording medium formed on a base film, and the recording medium
Form a printable protective film on the body and printed
Protects the recording / reproducing laser beam from passing through
In the area printed on the media side of the film,
It is configured so that the laser beam for recording and reproduction is not
Parallel to the light scanning direction and the pitch is
Is about 1 to 2 times the spot diameter focused by
In an optical tape printed in a
Light beam by a diffraction grating placed in front of the
The split beams are split into multiple beams perpendicular to the optical scanning direction.
In the racking direction, the light spot to be scanned by the light spot
Focus light at a position shifted back and forth across the search trajectory.
Converted the amount of reproduced light reflected from the focused spot
Use an objective lens or objective so that the signal amplitudes are equal.
Tracks laser light reflectors in front of the lens
The light spot on the recording medium
The optical scanning trajectory to be scanned by the
Optical tape device characterized by controlling to race
Place. At the time of recording, an objective lens is placed on an optical tape during recording.
Each scan of the light spot focused by the lens
Frequency of the low frequency pilot signal included in the
And at the time of playback, before the objective lens.
The light beam is divided into a plurality by the diffraction grating
Tracking of multiple split beams perpendicular to the optical scanning direction
In the scanning direction, the light scanning trajectory to be scanned by the light spot
The light is focused on tracks that are shifted back and forth between the
Signal obtained by photoelectrically converting the amount of reproduced light reflected from the light spot
Signal amplitude of the pilot signal included in
To move the light spot in the track direction
Driving the spot moving means to record the recorded light spot
Control to trace the inspection trajectory
Optical tape device.