JPS6257168A - Discriminating device for recording medium - Google Patents

Abstract

PURPOSE:To execute reproduction, etc. of a different disk, etc. by a single device, by detecting and discriminating optically a discriminating pattern which has been provided on other part than a normal recording area of a recording medium. CONSTITUTION:In a disk reproducing device 1 provided with a disk discriminating circuit 31, disk discriminating information provided on the outside of a recording area of a disk 3 is detected by an optical sensor 33 by driving to rotate the disk 3, a pulse corresponding to each reflecting part 32a is outputted from a binary-coding circuit 34, and the number of pulses is counted by a counter 35 and latched by a circuit 36. An output of this circuit 36 is converted to a discriminating signal SD of the disk 3 by a decoder 37 and applied to a signal processing circuit 20, and set automatically to a circuit system for executing a signal processing corresponding to the disk 3 of the device. In this way, with respect to a different disk, a normal reproducing level is set by a single device, an information data is reproduced without an error, and also a servo-system can also be operated stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording medium discriminating device that is capable of determining the type of recording medium used.

[Background Art] In recent years, the progress of industries related to information has been remarkable, and the amount of information being handled has also tended to increase dramatically.

Therefore, instead of a conventional magnetic head for recording and reproducing information, an optical head or an optical pickup using light is used to record information at high density and at high speed. Optical information recording and reproducing devices that can be used to play back information are attracting attention.

Various types of optical recording media have been proposed for use in the above-mentioned optical recording/reproducing apparatus, and the following types of recording media are currently being put into practical use.

For write-once recording media, (a) a perforation method using a metal thin film, (b) a perforation method using a dye, and (C) a reflection method using quality and amorphous changes. There is a variable rate method.

On the other hand, the replaceable type includes (d) magneto-optical type, (
0) Quality, there is one that uses amorphous r1 change.

Of course, these various recording media have different female inclusion light m.
The reflectance after writing is (a), (b), (e
) decreases, (C) increases, and (d) remains the same. In addition, (d) requires a magnetic field generation mechanism because the direction of magnetization of the recording medium must be reversed during writing and erasing. be. Further, in this case (d), reading uses rotation of the plane of polarization of the reflected light, so the reading light must be linearly polarized light. Conventional devices were designed to operate in accordance with a specific recording medium without considering compatibility with each recording medium at all.

[Problems to be solved by the invention] For example, in the recording medium (a), the reflected light m of the recording contact medium
As a result, the servo gain of focus servo, track servo, etc. decreases, so changes in reflected light from the recording medium are detected and the servo gain is increased. If the recording medium (C) is used in such an apparatus, the gain after recording increases too much, making the servo unstable, resulting in drawbacks such as inability to perform stable reading. Furthermore, since the media (a) to (Q) have different recording densities, writing may not be possible depending on the recording medium.

Furthermore, since the amplitude of the signals reproduced by recording media of different recording methods differs, problems arise such as, for example, a signal level that should originally be identified as a high level is erroneously reproduced as a low level. Therefore, by determining the type of recording medium,
It is necessary to perform an operation suitable for the recording medium.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a recording medium discrimination device capable of dealing with cases where the types of recording media are different.

[Means for solving the problems and their effects] In the present invention, a pattern corresponding to the type of recording medium is formed in a portion of the recording medium other than the regular data recording area, and this pattern is optically detected. The type of recording medium can be determined based on the output of the detection means.

[Example] Hereinafter, the present invention will be specifically described with reference to the drawings.

FIGS. 1 to 5 relate to the first embodiment of the present invention.
The figure shows an optical system of a disc playback device equipped with the first embodiment, FIG. 2 shows a disc provided with identification information indicating the type of disc, FIG. 3 shows a signal processing circuit, and FIG. The figure shows the polarization direction of reflected light in the case of a magneto-optical disk, and FIG. 5 shows signal output waveforms of various parts of the signal processing circuit.

The disk reproducing apparatus 1 equipped with the first embodiment is capable of reproducing an optical disk in which information is formed in bits and a magneto-optical disk using a magneto-optical method in the following manner.

As shown in FIG. 1, the optical system of the disk reproducing apparatus 1 is such that an optical disk 3A or a magneto-optical disk 3B can be attached to a spindle Tanabata 2 (a turntable driven by it).

(Both are simply referred to as disks 3.) An (optical) pickup 4 is provided opposite one of the γ disks 3, and this pickup 4 is fixed to a shaft 5 as a movable base. The carriage 5 is movable in the radial direction R of the disk 3 by a voice coil motor (not shown) or the like.

A laser diode 6 is housed in the pickup 4 as a monochromatic light source, and the light from the laser diode 6 is made into a parallel beam by a collimator lens 7, and then converted into a light beam with a circular cross section by a shaping polarizing prism 8. The light is made into a polarized light wave, passes through a beam splitter 9, passes through an objective lens 11, and is focused and irradiated onto the surface of the disk 3 in the form of a spot. A field coil 12 is disposed opposite the surface of the disk 3 on the side opposite to the pickup 4, so that a magnetic field in a predetermined direction can be generated on the magneto-optical disk 3B during erasing and recording.

When the disk 3 is a magneto-optical disk 3B, the light beam irradiated onto the disk 3 has an illuminated portion tJJ of S
Depending on whether it is magnetized to the pole or the north pole, the vibration planes of the reflected waves are rotated by a small angle θ in opposite directions due to the magnetic Kerr effect (one angle between the two is 2θ), and this reflected wave is transmitted to the objective lens 9. A part of the light is reflected by the beam splitter 9 and enters the half-wave plate 13 . Since the vibration plane of the half-wave plate 13 is set to point in the direction midway between the S axis and the P axis of the polarizing beam splitter 14, the polarizing beam splitter 14 The intensity of light incident on the side is indicated by Aα or Aβ as shown in FIG. Therefore, by passing the light through the polarizing beam splitter 14, which functions as an analyzer, the P@11 component and the S-axis component are received by the pin photodiodes 15a and 15b, respectively.

In this case, since the magneto-optical disk 3B is rotationally driven by the spindle motor 2, the direction of magnetization of the portion irradiated with the light beam is reversed according to the recorded information, and the pin photodiode 15a has Pffd of Aα and Aβ. Difference in components (
Modulated light that changes by the symbol QAp) is incident, and a photoelectric conversion signal 4U f38 corresponding to the intensity difference Ap is output from the pin photodiode 15a as shown in FIG. 5(a). On the other hand, from the other pin photodiode 15b, modulated light corresponding to the difference between the S-axis components of Aβ and Aα (indicated by the symbol "I'i A S) is inputted, and from this pin photodiode 15b, the light beams shown in FIG. As shown in b), a photoelectric conversion signal corresponding to the intensity difference AS is output.Therefore, as shown in FIG. ,
As shown in FIG. 5(C), a signal corresponding to the information recorded by the magneto-optical method can be obtained.

By the way, in the above-mentioned magneto-optical disk 3B, when information is recorded on the magneto-optical disk 3B, a track scent and a sector number are formed in pits in each track or a sector into which each track is divided in advance. −
(This is called a pre-pit.) Therefore, in the case of the fully distributed magneto-optical disk 3B, when a light beam is irradiated onto the pre-pit portion, the intensity of the reflected light changes depending on the presence or absence of pits, and the intensity of the reflected light changes depending on the presence or absence of pits. ．． It becomes a vector as shown by M. Therefore, in the above optical system, the intensity of light received by each photodiode 15a, 15b is determined by the symbol i in FIG.
The components are p and Is, and each photodiode 15a
, 15b is the above-mentioned Ip.

It is multiplied by a factor proportional to Is, and these are the fifth
These are indicated by the symbols ID- and ls- in Figures (a) and (b).

The intensity-modulated light whose intensity changes due to the pits is passed through the adder 22 in FIG. 5 (d).
), it is possible to obtain a signal with a large amplitude.

When reproducing the magneto-optical disk 3B, the pre-pit signal is output from the adder 22, and on the other hand,
Information data is output from the CV reducer 21.

On the other hand, in the case of the optical disc 3A, the adder 22 outputs both the BREPIP signal and the information data.

For this reason, the analog switch 23 is switched depending on the disk 3A or 3B used, and the information data signal is output from the data output terminal 01 via this (analog) switch 23. In addition, the above addition f'Es2
Since the amplitudes of the output signals of the subtracter 2 and the subtracter 21 are different (generally, the level on the subtracter 21 side is small), the output of the sigma reducer 21 is amplified by the amplifier 24 so that the levels match.

(In other words, the level corresponding to the high level is adjusted to have a normal high level value.) Note that the adder 22
The output terminal 02 outputs IQ data such as a track number. The output of the Ryogawa power OHO1,0□ is inputted to the control circuit 26 via the adder 25.

The disc identification information formed on the disc 3 is read out by the disc discrimination circuit 31 of the first embodiment, and the switch 23 is automatically switched to a state suitable for reproduction. As shown in FIG. 2, the disk 3 is provided with a data section in which information data is recorded along, for example, concentric tracks (spiral tracks are also suitable) and a pre-pit section in which track numbers and the like are recorded. A regular recording area is formed from the outer part of the central circular opening to the vicinity of the periphery of the disk 3.

Reflecting portions 32a, 32a, . . . , 32a of light in the circumferential direction outside the recording area, for example, outside the regular recording area, that is, outside the outermost track (indicated by ■HA).
is formed, and this reflective portion 32a.

. . , a disc identification pattern is formed that allows identification of whether the disc 3 is a magneto-optical disc 3B or an optical disc 3A based on the number of discs 32a.

Incidentally, for the light reflecting portions 32a, . . . , 32a, when forming the recording film of the disc 3, by using an f disk identification mask, portions where groups are formed and portions where groups are not formed are created. This is done so that the amount of foul light in the area is different from that in other areas.

An optical sensor +1I33 such as a photoreflector is disposed opposite the portion where the disc identification information based on the disc identification pattern is formed. A number of pulses corresponding to the number of reflecting portions 32a1, . This binarized signal is counted by a counter 35.

The counter 35 is reset by the one revolution signal Sr output from the spindle motor 2, and the output of the counter 35 is latched by the latch circuit 36 at a timing before being reset. The output of this latch circuit 36 is sent to a decoder 37 as a disc 3 discrimination signal S. The output from the decoder 37 controls switching of the switch 23. That is, when it is determined that it is a magneto-optical disk 3B,
The analog switch 23 is switched to the subtracter 21 side, and when it is determined that it is an optical disc, it is switched to the adder 22 side.

The output of the decoder 37 is also applied to the control circuit 26, so that the control signal level for tracking control or focus control is switched to a level suitable for the identified disc.

The discrimination signal q3° used for switching the switch 24, etc. is performed, for example, each time the disc playback device 1 is started, and thereafter (the output of the counter 35 or the latch circuit 36
(e.g., by fixing the output of the signal).

According to the disc playback device @1 equipped with the disc discrimination circuit 31 of the first embodiment configured as described above, when the disc 3 mounted on the turntable is rotated, the recording area of the disc 3 is Disc identification information provided on the outside is detected by the optical sensor 33, outputted from the binarization circuit 34 as a pulse corresponding to each reflection section 32a, and outputted to the counter 3.
5, the number of pulses is counted and latched by the latch circuit 36. Therefore, the output of the latch circuit 36 is transmitted to the decoder 3.
7 is the disk 3 discrimination signal S. This signal S
, is applied to the signal processing circuit 20, and is automatically set to a circuit system that performs signal processing corresponding to the mounted disk 3.

Therefore, for different discs 3, the device A can set the normal reproduction level, and the information data can be reproduced without error, and the servo system can be operated stably. Further, there is no need to take the trouble of changing circuit constants, constituent elements, etc. at t5° each time. Note that the reflecting portion 32a may be provided inside the innermost track.

(Of course, the position of the optical sensor 33 is changed accordingly.) FIG. 6 shows identification information means for the disk 3 according to a second embodiment of the present invention.

That is, in the circumferential direction of the disk surface outside the outermost track "HA" of the disk 3, that is, outside the regular recording area, there are, for example, two circles 41a, 41a, . . . , 41 at a coarse interval.
A disc identification pattern is formed by providing the number a corresponding to the scale type of the disc 3. The portion where the groove 41a is provided is designed to reflect light differently from the portion where the groove is not provided. Therefore, the signal level output from the optical sensor 33 as in the first embodiment is f141a
The level is different depending on the part where it is provided and the part where it is not provided,
Using a comparator or the like, it is possible to obtain a binarized belief pulse corresponding to the presence or absence of the groove 41a.

When the disc identification information means using the groove 41a is used, the circuit configuration of the first embodiment can be used as the disc discrimination circuit.

FIG. 7 shows the disc identification information means in the third embodiment.

That is, outside the outermost track "HA" of the disk 3,
A rough groove 418 and a dense groove 42a are provided, and the reflected light m incident on the objective lens side is different between the rough groove 41a portion and the dense groove 42a portion. In this case as well, the disc can be identified by the disc identifying circuit 31 shown in FIG. Note that the reflector tubes are not limited to having different reflecting tubes depending on the grooves, and the amount of reflection may be different depending on the degree of unevenness of the surface.

In each embodiment, disc identification information such as the disc type is formed in a portion other than the recording area of the disc 3 so as to be represented by the number of light reflecting parts, but it is not determined by the number of non-reflecting parts. It can be expressed in terms of the length of the reflective part or the non-reflective part. Further, the reflection amount is not limited to being different in two values, but may be set to be different in three values or more.

In the above embodiment, the case where an optical disk and a magneto-optical disk are discriminated and reproduced is described, but also when recording or erasing, the discriminated signal output is given a 1: and the corresponding action is taken. You can make it happen.

For example, in a device that can also perform recording on the optical disk 3Δ and the magneto-optical disk 3B, even in the recording mode, the discrimination signal S of the decoder 37 is used by the signal processing circuit 2o.
At the same time, it also controls the driving of the current source applied to the field coil 12. That is, when it is determined that the optical disc is the optical disc 3A, the current source swing f- is switched to A-f so that no current flows through the field coil 12, and when it is determined that the magneto-optical disc is the magneto-optical disc 3B, it is switched to A-on. Further, in the recording mode, the output level of the control system is made lower than in the reproduction mode, so that the control signal level is maintained at an appropriate level.

In addition, the present invention can be applied to recording media using different recording methods.

Furthermore, the present invention is not limited to disks as disc-shaped recording media, but can also be applied to card-shaped recording media. In the case of a card-shaped recording medium, card identification information is recorded in the card transport direction, and the information is read out by the number of pulses, width, etc. when the card is transported in this direction and is transported in one direction. It can also be provided in the scanning direction of the optical pickup.

Furthermore, the present invention is not limited to utilizing differences in light reflection nl, but may also utilize differences in transmitted light waves to determine the type of °C recording medium. In addition to recording medium identification patterns, information on level setting frames for various control signals is also recorded, and the level of the control system can be automatically selected and set to an appropriate level based on this information. You can also do that.

[Effects of the Invention] As described above, according to the present invention, an identification information means indicating the type of recording medium, etc. is provided in a portion of the recording medium other than the recorded information area, and an optical sensor is provided facing the recording medium. Since a recording medium discriminating means for discriminating identification information based on the detection signal is provided, a single device can play different discs, etc.

[Brief explanation of the drawing]

FIGS. 1 to 5 relate to the first embodiment of the present invention.
The figure is a block diagram showing the main parts of a disc playback device equipped with a disc discrimination circuit according to the first embodiment, FIG. 2 is a side view showing a disc provided with disc type identification information, and FIG. 1 shows the configuration of a signal processing circuit in which the signal processing system is switched by the output signal of the disk discrimination circuit. FIG. 4 is an explanatory diagram showing the polarization direction of reflected light in the case of a magneto-optical disk, and FIG. 5 C shows the signal processing. FIG. 6 is a front view showing a disk provided with disk identification information means according to the second embodiment of the present invention, and FIG. 7 is a waveform diagram showing the waveforms of the outputs of each part of the circuit. FIG. FIG. 3 is a front view showing a part of a disc provided with disc identification information means in an example. 1... Disc playback device 3... Disc 4...
Pickup 6...Laser diode 15a,
15b...Pin photodiode 20...Signal processing circuit 21...Subtractor 22...Adder f5 unit 23...(Analog) switch 26...Control circuit 31...Disc discrimination circuit 32a... ...Reverse (G) part 33... Optical sensor 3
4... Binarization circuit 35... Counter 36...
・Latch circuit 37...Decoder Figure 1

Claims (1)

[Claims] For recording media on which information data can be recorded, reproduced, or erased by irradiation with a light beam, an optical identification pattern is provided to identify the type of recording medium according to the reproduction or recording method. An optical sensor that is provided in a portion other than the regular recording area of the recording medium and that optically detects the identification pattern, and a discrimination circuit that determines the information of the identification pattern from the output of this optical sensor are provided. Features: Recording medium identification device.