JPH06187723A - Thin optical information processor - Google Patents

Abstract

PURPOSE:To obtain the information processor with superior portability and high reliability by its thin formation and miniaturization by making a structure capable of suppressing eccentricity of an optical disk less than a prescribed value. CONSTITUTION:A thin-optical disk device consists of an optical disk substrate 140, a cartridge 142, one part 144 of an outer wall of the disk device main body, a hub 149, an optical head 200, an objective lens 219, a spindle motor 244 and its spindle 242. In this device, for suppressing the eccentricity of the optical disk 140 to be <=0.1mm, the hub 149 provided in the rotating center of the optical disk 140 and the spindle 242 are made to touch each other in a tolerance of <=100mum. Then, the inner diameter of the hub 149 is provided on a concentric circle with a track, and moreover, an effective diameter of the objective lens 219 opposite to the track is shortened to 3.8-1.5mm, so that a focal distance is also shortened to be 0.5-0.6mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information processing apparatus, and more particularly to an information processing apparatus which is excellent in portability and has been made thin and small, and an optical disk used therein.

[0002]

2. Description of the Related Art A conventional technique for thinning an optical disk device is described in Japanese Patent Laid-Open No. 3-185630. This reduces the diameter of the objective lens to make it thinner.

The optical head having a smaller diameter of these objective lenses has a problem that the light utilization rate and the aberration increase with respect to the eccentricity of the disk, as compared with the conventional optical head.

[0004]

When an optical disc is used as a memory of a laptop computer or other portable information processing device, it is required to be thin.
It is disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-185630 that the thickness of the optical disk depends on the effective diameter of the objective lens 219. On the other hand, as will be described later, a write-once or rewritable type optical disk requires an NA of 0.5 or more, and the effective diameter is almost equal to the focal length. Therefore, it is necessary to shorten the focal length in order to reduce the thickness. This focal length is the distance from the principal point of the lens to the optical disc optical recording medium.
These are (1) the distance from the principal point of the lens to the lens surface, (2) the distance from the objective lens surface to the disk substrate surface, and (3) the distance from the disk surface to the recording medium.
(1) is about 1 mm even if an aspherical lens is used to reduce chromatic aberration, and (2) is called work distance,
With conventional optical discs, it was about 2 mm. The surface runout of the disk was allowed up to about 1 mm. Also, (3) has a thickness of 1.2 mm of the disk substrate, and these (1)-
When (3) is added, the focal length of the lens needs to be 4.0 mm or more. By the way, the light spot diameter d obtained on the surface of the recording film at the focal position is represented by d = λ / NA (Equation 1).

Here, NA: (D / 2) / √ ((D / 2) ² + f ² ) D / 2f λ: wavelength of light used D: effective diameter of objective lens f: focal length of objective lens is there.

That is, the light spot diameter d is inversely proportional to NA. That is, the light spot diameter d is inversely proportional to the lens diameter D and is proportional to the focal length f. The objective lens for high density recording needs to have an NA of 0.5 or more, and it is necessary to use an objective lens having an effective diameter equal to or more than the focal length. Since the thickness of the information processing device using the optical head is more than twice the effective diameter of this objective lens, the device cannot be made thin unless the effective diameter is made as small as possible.

Therefore, Japanese Patent Laid-Open No. 3-185630 proposes an optical head having a small effective diameter. However, if the diameter of the objective lens is reduced, the utilization efficiency of light is reduced due to the eccentricity of the disc, and the wavefront aberration of the focused spot is increased.

Therefore, it is an important subject to reduce the eccentricity of the disk in order to make the device thin and to provide a high performance optical head. The purpose is to reduce the thickness and size of optical heads and optical disk devices.

An object of the present invention is to provide an information processing apparatus which is excellent in portability, is thin, and has a recording medium exchangeable.

[0010]

The optical disk device of the present invention irradiates the optical memory for performing at least one of recording, reproducing or erasing of information and the light condensed by an objective lens to the optical memory, Recording information in optical memory,
An optical head for performing at least one of reproducing information recorded in the optical memory and erasing the information recorded in the optical memory; rotating means for rotating the optical memory; A drive circuit for controlling the operation and the rotation of the rotating means, in order to suppress the eccentricity of the optical disc to be 0.1 (0.2) mm or less, a hub and a spindle motor shaft provided at the rotation center of the optical memory. The contact is made with a tolerance of 100 μm or less.

Further, the inner diameter of the hub is provided concentrically with the track provided in the optical memory.

Furthermore, in order to reduce the effective diameter of the objective lens from 4 mm or more, which has been conventionally used, to 3.8 mm to 1.5 mm, the focal length is also reduced to 0.5 as in the conventional NA.
It was set to ~ 0.6. For example, when the effective diameter of the objective lens is 2 mm, the focal length is also 2 mm. This makes it possible to realize an optical system that can reduce the spot diameter to about 1.3 μm.

[0013]

In the optical head for realizing a thin optical disc device, the diameter of the objective lens is made small, but if the disc is decentered, the utilization factor of light fluctuates and the wavefront aberration of the focused spot becomes large. The disc chucking method of the present invention reduces eccentricity even in a compatible optical disc,
The fluctuation of the light utilization rate becomes small, and the wavefront aberration of the focused spot is kept in a range where it does not matter. Therefore, the power required for recording, erasing, and reproducing is stabilized in the thinned optical disk device. The present invention is configured to rotate the eccentricity of the disk below a certain value.

[0014]

EXAMPLE An example of the present invention will be described below.

FIG. 1A is a sectional view showing a state before loading of the thin optical disk device of the present invention. Since the overall thickness of the thin optical disk device is 1/10 or less of the device width, FIG. 1 shows the scale Y axis in the thickness direction and the scale X axis in the width direction with different scales. The thickness direction is shown magnified about 10 times.

In the figure, 140 is an optical disk substrate, 14
2 is a cartridge, 144 is a part of the outer wall of the disk device main body, 149 is a hub, and 200 is an optical head.
19 is an objective lens, 244 is a spindle motor, 2
42 indicates a spindle motor shaft.

The spindle motor 244 is the optical head 20.
There is also a shape that is not symmetrical about the axis so that 0 can be close to the center of the axis 242, and this figure shows it. The optical disk substrate 140 is in a state where it can move freely within the cartridge 142 before the hub 149 is fitted to the spindle. Figure 1
(B) shows a case where the disk substrate moves by the maximum amount in the width direction. At this time, a1 is a gap between the inner wall of the cartridge and the outer diameter of the disc 140, and the gap is zero when the disc 140 is maximally offset. At this time, the gap a2 on the opposite side is the difference between the inner wall dimension d1 of the cartridge and the outer diameter dimension of the disc 140. As will be described later, a hub 149 having a hole at the center of a concentric circular track provided in the disk is attached to the disk 140. The hub hole has a diameter of b1 and is made larger than the diameter b2 of the tip of the spindle motor shaft. Also, the tip and end of b2 are positioned and dimensioned so as to enter into b1 when they are maximally offset. Here, the cartridge 142 is vertically movable and descends toward the spindle motor shaft during loading.

FIG. 2A shows the case where the disk is biased to the opposite side, but the inner diameter of the hub 149 enters the tip of the tapered spindle motor shaft 242 and descends along the taper of the shaft. The disk is a cartridge 1
Move near the center of 42. FIG. 2B shows a state where loading has been completed.

The loading of the cartridge 142 is stopped by the stopper shown in FIG. 2 (b). Also,
The disc is supported by the flange of the shaft, and the cartridge 1
It floats up from 42 and is located almost in the center of the cartridge 142. This state is near the focal position of the objective lens of the optical head. In this state, the shaft rotates to drive the disc. The gap between the disc and the cartridge 142 is 2h
It is 0, and the surface wobbling of the disk caused by the tilt of the axis and the imbalance of the disk is less than this. Following this surface wobbling, focus servo control is performed so that the objective lens maintains a constant distance from the disc. Further, the length of the tip of the shaft is suppressed so as not to contact the upper lid of the cartridge 142. Since the present invention relates to a thin optical disk device, it is preferable that the thickness of the cartridge 142 and the length of the shaft are as short as possible. On the other hand, when the hub 242 and the shaft are fitted together, it is preferable that the taper portion is long, which is a contradictory condition. The present invention is directed to a surface deviation of a disc, an aberration of a light spot due to eccentricity, a cartridge 142 and a mechanism for supporting the cartridge 142,
The dimensions of the cartridge 142 and the outside of the disk 140 are obtained based on analysis and experimental data such as the accuracy in the height direction when the optical head moves in the radial direction of the disk, the accuracy in the height of the spindle motor shaft, and the like. I decided the diameter.

FIG. 3 is an example showing the external dimensions of the cartridge 142. As shown in FIG. 2, the hub hole of the disc 140 is positioned and dimensioned so as to enter the tip of the shaft when the disc 140 is maximally offset in the cartridge. The position of this hole depends on the relative position of the motor shaft and the stopper 144, the deviation of the disk 140 in the cartridge, and the dimensional accuracy of the cartridge. For this reason, the cartridge has a size that can be easily inserted into a loading mechanism (not shown), and a dimensional tolerance is set in order to obtain the positional accuracy of the hub 242 hole.

In the centering jig shown in FIG. 4, the disc positioning guide 147 and the central shaft 148 are manufactured on a concentric circle with high accuracy. With this centering jig 146, the disc 1
In 40, the outer circumference of the disk and the center axis of the centering jig 146 are easily set on a concentric circle.

In order to record a high density on an optical disc, 1.
Grooves or guide pits are provided in advance at intervals of about 5 μm. A line along the pit or groove is called a track, and data is read and written along the track, so that high density recording is possible. Since this track is provided concentrically with the outer circumference of the disk, the center axes of the track and the centering jig 146 are set concentrically. Since the central shaft 146 is manufactured with higher accuracy than the tolerance of the spindle motor shaft, the tolerance is small. Therefore, the inner diameter of the hub 149 is set to the central axis of the centering jig 146. In this state, the hub 149 and the disk substrate are fixed while the inner diameter of the hub 149 is pressed against the central axis. In this way, the center of rotation of the disc on which the disc and the hub 149 are fixed and the center of rotation of the hub 149 coincide with the center of the track of the disc. Here, an example in which a centering jig is used as a means for aligning the center of rotation of the hub with the center of the track has been described, but several other methods are possible. For example, the hub and the disk may be joined together and rotated, and the movement of the track may be measured. Then, the center of rotation of the hub may be aligned with the center of the track. Also, FIG.
In FIG. 4, the hub 242 is written in a different shape, but the center of rotation of the hub can be made to coincide with the center of the track of the disk.

FIG. 5 shows an example of measurement of the aberration of the objective lens caused by following the surface deflection and decentering of the optical disk. The specifications of the objective lens used for the measurement are an effective diameter of 2 mm, an optical disk side numerical aperture of 0.52, and a light source side numerical aperture of 0.14. The range in which the aberration caused by the objective lens is 0.045λ or less when the objective lens moves to follow the surface runout and decentering of the optical disk is shown. Marshall's limit of 0.07 as the standard for aberration that can focus light to the diffraction limit
There is λ (RMS). In the optical disc device, aberrations are generated by both the optical head and the optical disc, so that the same aberrations are allowed. Therefore, the aberration caused by the optical head needs to be 0.05λ (RMS) or less. Aberrations are caused not only by the objective lens but also by the semiconductor laser and the optical parts. Therefore, the aberration caused by the objective lens needs to be 0.045 λ (RMS) or less. Therefore, here, a range in which the aberration is 0.045λ or less was obtained. By the way, when the optical head is assembled, an error occurs between the central axis of the semiconductor laser light and the central axis of the objective lens. Further, an error also occurs in the distance between the optical disk and the optical head. Since it is usually difficult to make this mounting error 100 μm or less, the moving range of the objective lens with respect to the surface runout and decentering of the optical disk becomes narrow. From the above, the surface wobbling and eccentricity allowed for the optical disk are shown by the shaded area in FIG.
From this figure, the allowable surface runout is ± 340 μm or less and the eccentricity is ± 200 μm or less. To allow both surface runout and eccentricity at the same time, surface runout ± 100 μm or less, eccentricity ± 20
It should be 0 μm or less. Here, the surface wobbling is the variation in the distance from the light emitting point of the laser to the film surface of the disc,
The deviation from the absolute distance from the laser position to the disk position is included in this. Therefore, the error of this distance is 2
If the surface runout is 50 μm and the runout is 50 μm, the runout is 300 μm in FIG. 5, which is an allowable 50 μm.

FIG. 6 is a schematic sectional view showing the device thickness of the thin optical disk of the present invention. The diffused light emitted from the semiconductor laser becomes a parallel beam by the collimator lens and passes through the prism. This prism is equipped with a total reflection mirror,
It is condensed by the objective lens and becomes a minute spot on the optical disc. In this example, the light beam incident on the objective lens is parallel light and is called an infinite optical system. When the thickness is extremely thin, the thickness of this optical system is determined by the thickness of the prism, except for those required for the mechanism. Therefore, the diameter of the objective lens is reduced and the prism is made thinner. Up to this point,
No. 3-185630. However, it was revealed that when the objective lens is reduced, the light utilization rate is greatly reduced due to the eccentricity of the disc as shown in FIG. Therefore, the present invention is designed to reduce the eccentricity of the disk during rotation, as described above.

FIG. 7A shows the structure of an infinite optical head for an ultrathin optical disc. This is a basic structure of a recordable optical head, and since the light incident on the objective lens 219 is a parallel light flux, it is called an infinite optical system. Semiconductor laser 140
The laser beam emitted from is converted into a parallel beam by the collimator lens 212, and is incident on the compound prism 200. The compound prism is a module in which the functions of the shaping prism, the polarization beam splitter, the total reflection mirror for rising, and the quarter-wave plate are modularized into one prism. After the beam is shaped by the shaping prism of the compound prism 200, it is transmitted through the polarization beam splitter as P-polarized light, reflected by the total reflection mirror for standing up, and imaged on the optical disc by the objective lens 219. The direction of polarization of the laser beam reflected by the disk is changed by the quarter-wave plate, and is reflected by the polarization beam splitter as S-polarized light toward the detection optical system. The detection optical system is configured to obtain a focus error signal from a knife edge or a kamaboko lens and a tracking error signal from a Foucault prism for detecting diffracted light in the case of a grooved disk. The figure shows the case of the sample servo system, and only the focus error signal is obtained by the knife edge method. By the knife edge and the detection lens 220, an image is formed on the focus servo photodetectors 221Fa and 221Fb whose upper and lower light receiving surfaces are divided into two. Although there are various types of photodetectors, for example, there is a type that generates a current proportional to the amount of light, which is handled as a voltage value by current-voltage conversion.

The detection voltages of 221Fa and 221Fb change according to the relative distance between the objective lens 219 and the disk. This difference signal is hereinafter referred to as a focus error signal.
This focus error signal is proportional to the distance when the relative distance between the objective lens 219 and the disk is near the focal length of the objective lens 219, and the polarity is inverted before and after the focal length. In order to reduce the thickness of these optical systems, the optical axis was bent in the horizontal direction to perform beam shaping. The polarization beam splitter was oriented so that the reflection direction was toward the semiconductor laser 140, and the lead lines of the photodetector and the semiconductor laser 140 were in the same direction. Also, from the shaping prism 1
The optical elements up to the / 4 wavelength plate are manufactured as an integral prism so that the optical axis shift does not occur between these optical elements. Since these optical systems are made thin, the semiconductor laser 140 of the light source and the detector are suppressed within the horizontal plane.

FIG. 7B shows the configuration of a finite system optical head designed for cost reduction. The light incident on the objective lens 219 is diffused light from the semiconductor laser 140,
Since a light beam from a finite distance is focused on the disk by the objective lens 219, it is called a finite optical head. This finite optical head does not use a collimator lens, and the semiconductor laser 1
It is conceivable to reduce the cost, such as the need for highly precise position adjustment of the collimator lens 40 and the collimator lens. The finite system optical head has a configuration that has been put to practical use in CDs and the like, but in the present optical head that requires recording, the light utilization rate and aberrations become problems. In order to compare the above-mentioned infinite and finite optical heads, a common structure was used except for the optical head. As described in the previous report, all of these optical elements have been newly prototyped except for the detection lens and the detector.

FIG. 8 shows changes in the amount of eccentricity and the light utilization rate. The case of an infinite optical head and a finite optical head is shown. It can be seen that the light utilization rate is lowered in the disks with large eccentricity. Since this changes with one rotation of the disk, even if the recording or erasing power is kept constant, only this changes. Therefore, if the eccentricity is suppressed to 50 or less, the light utilization rate can be 2% or less even in the finite optical head.

As described above, if the eccentricity of the disk is suppressed to a certain value or less, the amount of movement of the objective lens for tracking decreases, so that the light utilization rate is high and stable. If the eccentricity of the disk can be suppressed, the effective diameter of the objective lens can be reduced, and the optical head can be thinned.

Next, the overall configuration of the information processing apparatus will be described.

FIG. 9 shows a tracking error signal indicating the eccentricity of the disk. The eccentricity of the disk can be measured by the density of tracking error signals obtained from concentric tracks. That is, a tracking error signal can be obtained from a groove or a pit provided on the disk by a focus servo that simply causes the objective lens to follow the surface wobbling of the disk. In this case, since the objective lens is fixed in the radial direction, the coarse state of the error signal generated due to the eccentricity of the disk is the state with little eccentricity, and the dense state is the state with large eccentricity. Therefore,
Observing one rotation of the disk reveals the phase of the disk's eccentricity. Also, the amount of eccentricity can be known by counting the number of peaks of this tracking error signal. The present invention counts this number and stops the rotation of the disk when the eccentric amount is equal to or more than a certain amount, that is, the eccentric amount is equal to or more than the certain amount. Also, the disc was once ejected and reloaded. As a result, the eccentricity of the disc varies depending on the range of variations at the time of loading, and it may be less than a certain amount.
Even if this is repeated several times, discs that do not fall below a certain amount are ejected.

FIG. 10 illustrates the drive circuit 260 in detail. The disk device is configured so that when the disk is mounted on the spindle, the disk starts to rotate automatically or according to a start signal.

The drive circuit 260 includes a microprocessor 400, a track address control section 262, a track control section 263, a focus control section 264, and a photodetection amplification section 2.
65, a signal demodulator 266, a signal modulator 267, a laser drive circuit 268, and a motor controller 269.
With such a configuration, at the time of recording or erasing data, the track address control unit 262 determines the track address to be recorded, and the signal modulation unit 267 is required for the data provided from the processor 400 to be corrected by the error correction code control LSI. A code is added, and the code conversion unit converts the pattern into "0" and "1" patterns. The modulation method for recording on the optical recording medium 140 is 2
There are -7 modulation and 4-15 modulation, which are used depending on the system. The laser driving circuit 268 modulates the laser power between the erasing power and the recording power as shown in FIG. 11 according to the pattern of “0” and “1” determined by the signal modulator 267.

That is, at the time of recording / erasing, the optical head 210
By modulating the power of the semiconductor laser incorporated in the disc between the erasing power and the recording power as shown in FIG. 12, new information is recorded on the old information. Also,
During reproduction, the reflectivity of the optical disk is read by narrowing the power of the semiconductor laser to a relatively small power and irradiating continuously.

When reproducing data, the processor 400
The drive address designated by is selected, the laser power is set to a constant value of approximately 1 to 2 mW, and the photodetector amplifier 26
5, the reflectance of the optical recording medium 144 is read, and the signal demodulation unit 266 demodulates the data. The result of the photodetector amplifier 265 is also used as a signal for the track control 263 and the focus control 264, but the function of this part can be realized by the function used in the information processing apparatus represented by the conventional compact disc. In addition, the motor control unit 2
69 is a motor 240 for rotating the optical recording medium 144.
Control the rotation speed of.

FIG. 12 shows a tracking error signal in the case of the conventional optical disk hub 149 structure. The interchangeable optical disc has a small tolerance of the inner diameter of the hub 149 due to the tolerance of the inner diameter of the rotation shaft and the hub 149 of the disc.
Designed to. For this reason, if eccentricity occurs in the range of the tolerance difference μm between the rotary shaft and the hub 149, a tracking error signal is generated as the disk rotates. This figure shows Disk 1
This is a rotation error signal, and about 60 peaks occur in a sine wave shape. Since the amount of eccentricity is half this, the eccentricity is 30 tracks, and the track pitch of this disk is 1.5 μm.
From m 2, it can be seen that the eccentricity is 45 μm.

FIG. 13 shows a hub 149 of the optical disk of the present invention.
The tracking error signal in the case of a structure is shown. In a replaceable optical disc, even if the tolerance of the inner diameter of the spindle motor shaft 242 and the disc hub 149 is large, the rotation center of the disc and the spindle motor shaft 242 is several μm as described above.
Is fitted to. For this reason, the eccentricity between the spindle motor shaft 242 and the hub 149 is within a few μm, and the error signal for one rotation of the disk has about 8 peaks. Since the amount of eccentricity is half this, it is understood that the eccentricity is 4 tracks, and the eccentricity is 6 μm from the track pitch of this disk of 1.5 μm. FIG. 14 shows one means for measuring the amount of eccentricity of the optical disc of the present invention. The tracking error signal is compared by the comparator, and if it is larger than a certain value, the comparator outputs TTL.
The level output is input to the counter, and the eccentricity amount can be known by counting this pulsed signal. When the amount of eccentricity exceeds a preset value, the disc is ejected as defective loading.

[0038]

According to the present invention, the eccentricity of the disk is set to a predetermined value or less, so that the objective lens 21 based on tracking can be obtained.
Since the movement of 9 is reduced, the aberration is small, the spot is focused to the diffraction limit, and the light utilization efficiency is high. By suppressing the eccentricity in this way, the lens diameter of the objective lens can be reduced in a practical optical disk device, and thus the optical head can be made thinner.

According to the present invention, the objective lens 219 by tracking is set by setting the eccentricity of the disc to be a certain value or less.
Since the movement of the lens is reduced, the power consumption for moving the lens is reduced, and the optical head can be made thinner as a portable device.

The present invention has a means for recognizing the eccentricity of the disk, and when the disk is loaded and the eccentricity at the time of starting the rotation is larger than a preset value, the rotation of the disk is stopped and the loading of the disk is stopped. Try again. Alternatively, a mechanism for ejecting the disc is provided. Therefore, since the normal disk is in a disk state with less eccentricity when the normal loading is executed, the diameter of the objective lens can be reduced, and thus the optical head can be thinned.

By using the optical disk of the present invention, it is possible to realize a thin laptop computer having a large capacity memory, a large capacity still camera, and a portable medical personal database having a large capacity memory.

If the eccentricity of the disk is kept below a certain value, the amount of movement of the objective lens for tracking is reduced, and the light utilization rate is increased. Further, in the finite optical system, since the deviation between the light source, the spot on the disc 140 and the lens position is small, the wavefront aberration condensed on the disc 140 is small. For these reasons, the effective diameter of the objective lens can be reduced, so that the optical head can be made thinner.

[Brief description of drawings]

FIG. 1 is a diagram showing a state before fitting of the present invention.

FIG. 2 is an explanatory diagram showing a procedure for loading a disc of the present invention.

FIG. 3 is an embodiment showing the shape of the cartridge of the present invention.

FIG. 4 is an embodiment of aligning the center of rotation of the track with the center of rotation of the hub of the present invention.

FIG. 5 is an actual measurement value of aberration due to eccentricity and surface wobbling of a disk.

FIG. 6 is a diagram showing an example of the thickness of the thin disk device of the present invention.

FIG. 7 is an overall schematic diagram of an optical system.

FIG. 8 is a diagram showing eccentricity and light utilization rate.

FIG. 9 is a tracking error signal indicating an eccentric state.

FIG. 10 shows an example of a drive circuit system necessary for realizing the present invention.

FIG. 11 is an explanatory diagram of laser power during overwriting.

FIG. 12 is a tracking error signal of a conventional hub.

FIG. 13 is a tracking error signal according to the hub of the present invention.

FIG. 14 is a modification of the present invention.

[Explanation of symbols]

100 ... Beam, 140 ... Optical disk, 149 ... Hub,
211 ... Semiconductor laser, 212 ... Collimating lens, 2
42 ... Spindle motor shaft, 244 ... Drive pin, 143
... Drive pin hole, 219 ... Track objective lens, 400 ...
Microprocessor.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number for FI GI technical display location G11B 23/03 Z 7201-5D (72) Inventor Yoshio Sato 7-1, Omika-cho, Hitachi-shi, Ibaraki No. 1 Hitachi Ltd., Hitachi Research Laboratory (72) Inventor Tetsuya Fushimi 7-1-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Saburo Yasukawa Hitachi Mita, Ibaraki Prefecture 7-1-1, Machi, Hitachi Research Laboratory, Hitachi, Ltd. (72) Hideo Shibanuma, 7-1-1, Omika-cho, Hitachi City, Ibaraki Hitachi Ltd., Hitachi Research Laboratory, Ltd.

Claims (9)

[Claims] 1. An optical memory for performing at least one of recording, reproducing or erasing information, and irradiating the optical memory with light condensed by an objective lens to record information in the optical memory. An optical head for performing at least one of reproducing recorded information and erasing information recorded in the optical memory; rotating means for rotating the optical memory; operation of the optical head; An information processing apparatus, comprising: a drive circuit for controlling rotation of a rotating means, wherein a mechanism for suppressing eccentricity of an optical disc to 200 μm or less is provided. 2. An optical memory for performing at least one of recording, reproducing or erasing of information, and irradiating the optical memory with light condensed by an objective lens having an effective diameter of 3 mm or less and 1 mm or more to store information in the optical memory. An optical head for performing at least one of recording, reproducing information recorded in the optical memory, and erasing the information recorded in the optical memory; rotating means for rotating the optical memory; An information processing apparatus having a drive circuit for controlling the operation of the optical head and the rotation of the rotating means, wherein a mechanism for suppressing the eccentricity of the optical disc to 200 μm or less is provided. 3. An optical memory for recording, reproducing or erasing information, and irradiating the optical memory with light condensed by an objective lens to record the information in the optical memory. An optical head for performing at least one of reproducing recorded information and erasing information recorded in the optical memory, a central hole of a hub provided in the optical memory, and a drive-side rotating shaft. The information processing apparatus is characterized in that the tolerance is less than 200 μm and more than 10 μm. 4. An optical memory for recording, reproducing or erasing information, and irradiating the optical memory with light condensed by an objective lens to record information in the optical memory. An optical head for executing at least one of reproducing recorded information and erasing information recorded in the optical memory, and a rotation center of a center hole of a hub fitted with a rotation center axis of a driving side. Is 150 μm or less with respect to the center of a track provided in the optical memory. 5. An optical memory for performing at least one of recording, reproducing and erasing information, and irradiating the optical memory with light condensed by an objective lens to record information in the optical memory. An optical head for performing at least one of reproducing recorded information and erasing information recorded in the optical memory; rotating means for rotating the optical memory; operation of the optical head; An information processing apparatus having a drive circuit for controlling the rotation of a rotating means, wherein the tolerance of the inner diameter of the cartridge for protecting the disc and the outer diameter of the disc is 200 μm or less. 6. An optical memory for recording, reproducing or erasing information, and irradiating the optical memory with light condensed by an objective lens to record information in the optical memory. An optical head for performing at least one of reproducing recorded information and erasing information recorded in the optical memory; rotating means for rotating the optical memory; operation of the optical head; A drive circuit for controlling the rotation of the rotating means, the external dimension tolerance of the disk is 0-100 μm.
An optical disc and a device characterized in that 7. An optical memory for performing at least one of recording, reproducing and erasing information, and irradiating the optical memory with light condensed by an objective lens to record information in the optical memory. An optical head for performing at least one of reproducing recorded information and erasing information recorded in the optical memory; rotating means for rotating the optical memory; operation of the optical head; An optical disk and a device having a drive circuit for controlling the rotation of a rotating means, wherein an inner diameter dimension tolerance of the disk cartridge is set to 0 to 100 μm. 8. An optical memory for recording, reproducing or erasing information, and irradiating the optical memory with light condensed by an objective lens to record information in the optical memory. An optical head for performing at least one of reproducing recorded information and erasing information recorded in the optical memory; rotating means for rotating the optical memory; operation of the optical head; An information processing apparatus, comprising: a drive circuit for controlling rotation of a rotating means, wherein a tolerance of outer dimensions of a disk cartridge is 100 μm or less. 9. An optical memory for recording, reproducing or erasing information, and irradiating the optical memory with light condensed by an objective lens to record information in the optical memory. An optical head for performing at least one of reproducing recorded information and erasing information recorded in the optical memory; rotating means for rotating the optical memory; operation of the optical head; A drive circuit for controlling the rotation of the rotating means, having means for recognizing the eccentricity of the optical memory,
An information processing apparatus characterized in that a disc having an eccentricity exceeding a certain range is configured to stop rotation once and to be loaded again as a defective loading or a defective disk.