JP2001209955A - Driving device for optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device which is capable of subjecting two information recording layers to recording, reproducing, etc., without the inversion of the front and rear of an optical information recording medium. SOLUTION: A first optical head 12 and a second optical head 13 are arranged on both sides of a spindle motor 11 via the optical information recording medium 1 mounted at the motor. These first and second optical heads 12 and 13 are mounted to face each other at a head holder 14 and are transferred simultaneously to the same extend in the same direction by driving the head holder 14. A tracking error signal is detected from the optical information recording medium 1 by the one optical head 12 and the tracking control of the first and second optical heads 12 and 13 is executed in accordance with the detected tracking error signal. An information recording medium constituted by forming a light reflective film 4 inhibiting or allowing DRAW of information on a preformat pattern forming surface 3 of a transparent substrate 2 and laminating an optical recording film on the light reflective film 4 is used as the optical information recording medium 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for recording and reproducing information by mounting a double-sided recording type optical information recording medium.

[0002]

2. Description of the Related Art Conventionally known double-sided recording type optical discs have a pre-format pattern having at least a light beam guide on a transparent substrate having fine irregularities formed on one side. A single optical disk having at least a recording film or a reflection film formed thereon is integrally laminated with the recording film or the reflection film inside.

On the other hand, a conventionally known drive device for a double-sided recording type optical disk is provided with only one optical head for recording and reproducing information on the optical disk. When performing recording, reproduction, or the like on one of the information recording layers, the optical disc is mounted on a spindle motor with the one information recording layer facing the optical head, and recording and reproduction on the other information recording layer are performed. When performing reproduction or the like, the optical disk is turned upside down, and the other information recording layer is mounted on a spindle motor with the optical recording head facing the optical head, thereby recording and reproducing information.

[0004]

By the way, with respect to producing a transparent substrate with a preformat pattern,
First, a preformat pattern of micron order or submicron order is optically cut on the master, and then a conductive film is formed by sputtering on the preformat pattern forming surface of the cut master.
Using this conductive film as one electrode, electroforming (thick plating) is performed, and the interface between the preformat pattern forming surface of the master and the conductive film is peeled off. Take out the transferred stamper, and then use this stamper as a mold to obtain a replica on which the same preformat pattern as that cut on the master has been transferred. Since it is difficult to manufacture the optical disk in a satisfactory manner, the manufacturing cost of the optical disk increases. In particular, when two types of optical discs having different preformat patterns are used, such inconvenience becomes remarkable.

[0005] Further, since the conventional drive device is provided with only one optical head, in order to record and reproduce information on different information recording layers as described above, each time it is performed. The optical disk must be taken out of the drive device and turned upside down, not only is it cumbersome to use, but it is not possible to record information across two information recording layers, so recording with only one information recording layer There is an inconvenience that data having an enormous amount of data cannot be recorded.

The present invention has been made in view of such circumstances, and has as its object to record and reproduce information on two information recording layers without inverting the optical information recording medium. A drive device is provided.

[0007]

According to the present invention, there is provided a drive unit for an optical information recording medium, and an optical head for optically recording and reproducing information on the optical information recording medium. And a first optical head and a second optical head are disposed on both sides of the optical information recording medium mounted on the drive unit via the optical information recording medium. In one of the optical heads, a tracking error signal of a light beam is detected from a preformat pattern formed on the optical information recording medium, and tracking control of the two optical heads is performed based on the tracking error signal. did.

According to this configuration, the first optical head and the second optical head are arranged on both sides of the optical information recording medium mounted on the drive unit, and one of the two optical heads is provided. One of the optical heads detects a tracking error signal of a light beam from a preformat pattern formed on the optical information recording medium, and performs tracking control of the two optical heads based on the tracking servo signal. Information can be recorded and reproduced on an information recording layer having no (light beam guide), and the configuration of the optical information recording medium to be used can be simplified and the cost can be reduced. it can. Also, since it is not necessary to turn the optical information recording medium upside down, it is convenient to use, and it is possible to use it in an unprecedented usage mode such as recording a series of information over two information recording layers. .

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to description of a drive device according to the present invention, an example of the configuration of an optical information recording medium applied to the drive device will be described with reference to FIGS. FIG. 1 is a sectional view of an optical information recording medium according to the present embodiment, FIG. 2 is a plan view of a main part, and FIG. 3 is a plan view of the entire configuration.

As shown in FIG. 1, an optical information recording medium 1 of the present embodiment has a transparent substrate 2 having a preformat pattern 3 formed on one surface and a transparent substrate 2 having a preformat pattern 3 formed on the transparent substrate 2. Reflective film 4, a recording film 5 laminated on the reflective film 4, and a transparent protective film 6 covering the outer surface of the recording film 5, and the preformat pattern 3 and the reflective film 4 And the information recording film 5 constitutes a second information recording layer.

The transparent substrate 2 is made of, for example, a transparent ceramic material such as glass, or a transparent plastic material such as polycarbonate, polymethyl methacrylate, polymethyl pentene, epoxy, or a photo-curable resin. It is formed in a disk shape having a desired diameter and having a hole 2a.

The preformat pattern 3 includes, for example, a guide groove for providing a tracking servo signal to an optical head, and a pit row representing a header signal and an information signal.
It is formed on one surface of the transparent substrate 2 in the form of fine irregularities.
In the example of FIG. 2, a pre-pit row 8 representing a header signal and a pre-pit row 9 representing an information signal are formed on the guide groove 7. Note that the configuration of the preformat pattern 3 is not limited to the configuration shown in FIG. 2, but may be configured in the same manner as the preformat pattern formed on the compact disc. Also, it is possible to preformat only a signal necessary for guiding the optical head without including an information signal. In any case, the preformat pattern 3 is, as shown in FIG.
It is formed in a spiral or concentric shape concentric with a.

When the configuration as shown in FIG. 2 is adopted, the guide groove 7 and the pre-pits 8, 9 are formed at different depths from each other in order to give a contrast to the intensity of the reflected light when the reproduction light is irradiated. You. For example, when the wavelength of the reproduction light is λ and the refractive index of the transparent substrate 2 is n, the guide groove 7 is formed at a depth of λ / 6n to λ / 8n. 9 is formed at a depth of λ / 4n to λ / 6n. That is, the guide groove 7 or the pre-pit 8,
When a portion 9 is irradiated with reproduction light, the intensity of reflected light is reduced due to light interference and diffraction. On the other hand, the guide groove 7
In addition, when the reproduction light is irradiated to a portion where the pre-pits 8 and 9 are not present, a phenomenon such as light interference and diffraction does not occur, so that the reflected light intensity does not decrease. Therefore, the presence or absence of the guide groove and the pre-pit can be detected by detecting the intensity of the reflected light from the optical information recording medium 1 with the photodetector. Further, since the guide groove 7 and the pre-pits 8 and 9 have different reflected light intensities due to the difference in their depths,
Can be identified.

The preformat pattern 3 is formed by an appropriate method according to the material of the transparent substrate 2. For example, when the transparent substrate 2 is formed of a thermoplastic resin such as polycarbonate, polymethyl methacrylate, and polymethyl pentene, the molten substrate material is injected into a molding die, and the transparent substrate 2 having the preformat pattern 3 is formed. A so-called injection method for forming the substrate 2 is suitable. Further, a so-called compression method or an injection-compression method in which pressure is applied after injecting the substrate material into the mold, or the like can be applied. Further, when the transparent substrate 2 is formed of a transparent ceramic material such as glass or a thermosetting resin such as an epoxy resin, for example, the transparent substrate 2 is formed between the stamper on which the inverted pattern of the preformat pattern is formed and the transparent substrate 2. The so-called 2P method (photocurable resin method) in which a photocurable resin is spread and the inverted pattern of the stamper is transferred to the transparent substrate 2 is suitable. Further, when the transparent substrate 2 is formed of a thermosetting resin such as an epoxy resin or a photo-setting resin,
A so-called casting method in which a substrate material in a molten state is injected intravenously into a mold to form a transparent substrate 2 with a preformat pattern is suitable.

The reflection film 4 has a high reflectivity to light for reproduction, such as a metal material such as gold or aluminum, an alloy material containing these metal materials as a main component, and a so-called silver mirror, and is not involved in information recording. Formed by material. When a metal material is used, the reflective film 4 can be formed by using a vacuum film forming method such as vacuum evaporation or sputtering.

The recording film 5 can be formed using any known heat mode recording material or photon mode recording material. As a heat mode recording material,
For example, low-melting alloy materials mainly containing tellurium, selenium, and lead, and magneto-optical recording materials such as amorphous alloys mainly containing terbium, iron, and cobalt, and arsenic, tellurium, and germanium as main components. Examples include phase-change recording materials such as amorphous alloys.Photon mode recording materials include, for example, polymethine dyes, anthraquinone dyes, cyanine dyes, phthalocyanine dyes,
Organic dye recording materials such as xanthene dyes, triphenylmethane dyes, pyrylium dyes, azulene dyes, and metal-containing azo dyes can be mentioned. When an organic dye-based recording material is used, the recording film 5 can be formed by a spin coating method. When another recording material is used, the recording film 5 can be formed by a vacuum film forming method such as vacuum evaporation or sputtering. Can be formed.

The protective layer 6 is made of, for example, AlN, Al ₂ O ₃ ,
It can be formed of an inorganic material such as SiN or SiO ₂ or an organic material such as an ultraviolet curable resin.
When an inorganic material is used, the protective layer 6 can be formed by sputtering or vacuum deposition, and when an ultraviolet curable resin is used, after spin-coating on the recording film 5, it is cured by irradiating ultraviolet rays. The protective layer 6 can be formed by using such a method.

In the above embodiment, the recording film 5 is directly laminated on the reflection film 4, but another thin film may be interposed.

The configuration of a drive device for recording and reproducing information by mounting the optical information recording medium configured as described above will be described below with reference to FIG.

FIG. 4 is a block diagram of the drive apparatus according to the present invention, wherein 1 is the optical information recording medium shown in FIGS. 1 to 3, 11 is a spindle motor for rotating the optical information recording medium 1, and 12 is A first optical head 13 for reading information from the first information recording layer, and a second information recording layer (recording film 5)
2 shows a second optical head for performing recording, reproduction, and the like of information between them. The first optical head 12 and the second optical head 13 are attached to the head holding device 14 so as to face each other, and by driving the head holding device 14,
It is simultaneously transported by the same amount in the same direction. The first optical head 12 is disposed opposite to the transparent substrate 2 of the optical information recording medium 1 at a predetermined distance from the transparent substrate 2, and the second optical head 13 is connected to the protective layer 6 of the optical information recording medium 1. Are arranged opposite to each other with a predetermined space therebetween.

The spindle motor 11 includes time base servo means (not shown), and drives the optical information recording medium 1 to rotate in a predetermined rotation mode based on a reference clock. The first optical head 12 is provided with a signal detecting system for detecting a tracking error signal from the optical information recording medium 1 and a tracking servo means including an actuator for driving an objective lens based on the detected tracking error signal. The laser beam 15 emitted from the optical head 12 can always follow the preformat pattern 3 formed on the transparent substrate 2. On the other hand, the second optical head 13 is provided with only the actuator of each device constituting the tracking servo means, and is detected from the optical information recording medium 1 by the first optical head 12. A tracking servo is applied to the objective lens by a tracking error signal. Each of the optical heads 12 and 13 is provided with a focus servo means for constantly focusing the emitted laser beam 15 on the interface between the preformat pattern 3 and the reflective layer 4.
Since the focus servo means is a well-known technique and has no direct relation to the gist of the present invention, the description will be omitted.

The optical information recording medium 1 is attached to the spindle motor 11.
Is mounted, the reflection film 4 is opposed to the first optical head 12, and the recording film 5 is opposed to the second optical head 13. The head holding device 14 is driven by a controller (not shown), and the first optical head 12 is When a desired track is accessed, a tracking error signal is optically read from a guide groove formed along the track. Therefore, by driving the actuator based on the tracking error signal, it is possible to apply tracking servo to the first optical head 12, whereby the header signal, the reference clock, and the information signal preformatted on the transparent substrate 2 can be obtained. Can be read out optically. Further, a tracking servo is applied to the second optical head 13 based on the tracking error signal read by the first optical head 12, whereby information can be recorded and reproduced on the recording film 5. .

The optical information recording medium 1 comprises a recording film 5 laminated on a reflective film 4 formed on a preformat pattern 3 and a single-sided recording substrate having only a preformat pattern. Since the recording medium is configured, the manufacturing cost of the double-sided recording type optical information recording medium can be reduced. In the drive device according to the embodiment, the first optical head 12 and the second optical head 12 are arranged on both sides of the optical information recording medium 1 mounted on the spindle motor 11, One of the two optical heads detects a tracking error signal of a light beam from a preformat pattern 3 formed on the optical information recording medium 1, and based on the tracking error signal, the two optical heads Since tracking control is performed on the recording layers 12 and 13, information can be recorded and reproduced on the recording film 5 having no preformat pattern. Moreover, since the optical information recording medium 1 does not need to be turned upside down, it is convenient to use, and can be used in an unprecedented usage mode such as recording a series of information over two information recording layers. .

Next, a second example of an optical information recording medium applicable to the drive device of the present invention will be described with reference to FIG. FIG.
Is a sectional view of a main part of the optical information recording medium according to the present embodiment,
1 is a protective plate, 22 is an inner spacer, 23 is an outer spacer, 24 is an air space, and other portions corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals.

As shown in FIG. 5, in the optical information recording medium 1 of this embodiment, the recording film 5 is formed on the inner surface of the protective plate 21 having no preformat pattern, and the recording film 5 and the reflection film 4 An air space 24 is provided therebetween. Although the recording film 5 is shown as a single layer in FIG. 5, it is a matter of course that other thin films can be laminated as needed. The protective plate 21 is made of a transparent material similar to that of the transparent substrate 2 and is formed in a disk shape having the same diameter as the transparent substrate 2.
The optical information recording medium 1 of the present embodiment is concentrically combined with a disk having a reflective film 4 formed on a preformat pattern forming surface 3 of a transparent substrate 2 and a disk having a recording film 5 formed on one surface of a protective plate 21. The inner peripheral portion and the outer peripheral portion can be formed by bonding the inner peripheral portion and the outer peripheral portion via the inner peripheral spacer 22 and the outer peripheral spacer 23. The other parts are the same as those of the optical information recording medium shown in FIGS.

The optical information recording medium 1 of the present embodiment also has the structure shown in FIGS.
The same effect as the optical information recording medium shown in FIG.

Next, a third example of an optical information recording medium applicable to the drive device of the present invention will be described with reference to FIG. FIG.
Is a sectional view of a main part of the optical information recording medium according to the present embodiment,
Reference numeral 5 denotes an organic dye layer, and other portions corresponding to those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

As shown in FIG. 6, an optical information recording medium 1 of the present embodiment has a preformat pattern forming surface 3 of a transparent substrate 2.
And an organic dye layer 25 is interposed between the reflective film 4 and
Information can be recorded not only on the recording film 5 but also on the organic dye layer 25. Examples of the organic dye material forming the organic dye layer 25 include spiropyran dyes, fulgide dyes, cyanine dyes, phthalocyanine dyes, polymethine dyes, anthraquinone dyes, xanthene dyes, triphenylmethane dyes, and pyrylium dyes. Dyes, azulene dyes, metal-containing azo dyes, etc., have a light reflectance of 60 to 80% and a light absorption of 20 to 40%, absorb laser light and convert it to heat, and reflectivity For example, a material whose optical characteristics change can be used. Note that when a spiropyran-based dye or a fulgide-based dye is used, a rewritable optical information recording medium capable of erasing and rewriting information can be manufactured.When a cyanine-based dye or a phthalocyanine-based dye is used, A write-once optical information recording medium on which information can be written only once can be manufactured. The organic dye layer 25 is formed by extending the organic dye material between the stamper on which the desired preformat pattern reverse pattern is formed and the transparent substrate 2, curing the organic dye material, and forming the organic dye layer 25 with the stamper. Can be formed by peeling off from the interface. The other parts are the same as those of the optical information recording medium of the first embodiment, and the description is omitted.

The information recording medium 1 of the present embodiment focuses on the light beam spot for reproduction at the interface between the preformat pattern 3 and the organic dye film 25, and detects the reflected light from the reflection film 4 to perform the preformat. The read address signal or the recorded information signal can be read. Also,
The recording light beam spot is focused on the desired address read in this way, the light energy is absorbed by the organic dye film 25 and converted into heat.
Information can be additionally recorded by locally discoloring 5 or the like.

In this embodiment, the recording film 5 is laminated on the reflection film 4. However, similarly to the optical information recording medium shown in FIG. An air layer may be provided between the recording layer 5 and the recording layer 5.

Further, in each of the above-described examples, a material in which information cannot be additionally recorded is provided as the reflection film 4. However, an alloy material in which information can be additionally recorded by optical means can be used as the reflection film 4. Examples of the alloy material to which information can be additionally written by optical means include, for example, at least one element selected from the [Ge, Si, Sn] element group and [Au, A].
g, Al, Cu] element group. Of course, Tl, C
o, Fe, Ni, Sc, Ti, V, Cr, Mn, Zn,
Y, Zr, Nb, Mo, Ru, Rh, Pd, Cd, H
f, Ta, W, Re, Os, Ir, Pt, Te, Se,
Including at least one of Sb, S, Hg, As, B, C, N, P, O, a halogen element, an alkali metal element, an alkaline earth metal element, an actinide element, a lanthanide element, an inert gas element, and the like. But it is good.

Of the above elements, Co, Ni, Sc, T
i, V, Cr, Mn, Zn, Y, Zr, Nb, Mo, R
u, Rh, Pd, Cd, Hf, Ta, W, Re, Os,
Ir, Pt, and Fe have an effect of facilitating absorption of long-wavelength light such as a semiconductor laser beam to increase recording sensitivity, and enable high-speed crystallization. Te, Se, Sb, and S have the effect of increasing the stability of the amorphous state and improving the oxidation resistance. Tl, a halogen element, and an alkali metal element have the effect of increasing the crystallization rate and increasing the stability of the amorphous state. N, O, and Ar have the effect of increasing the stability of the amorphous state. In addition, rare earth elements and the like can play a role such as increasing the crystallization temperature.

The information recording medium 1 of this embodiment is obtained by focusing a low-power reproducing light beam spot on an interface between a preformat pattern 3 formed on a transparent substrate 2 and a reflective film on which information can be additionally written. A formatted address signal or a recorded information signal can be read. Further, a high-power recording laser beam spot is focused on the desired address read out in this manner, the light energy is absorbed by a recording film on which information can be additionally written, and converted into heat. The information can be additionally recorded by locally deforming (for example, drilling) a recording film on which information can be additionally recorded. Of course, the second optical head 13
By driving (see FIG. 4), recording and reproduction of information on the recording film 5 can be performed.

[0034]

As described above, in the drive device of the present invention, the first optical head and the second optical head are arranged on both sides of the optical information recording medium mounted on the drive unit, One of these two optical heads detects a tracking error signal of a light beam from a preformat pattern formed on the optical information recording medium, and based on the tracking servo signal, detects the two optical heads. Since the head is subjected to tracking control, information can be recorded and reproduced on the information recording layer having no preformat pattern, and the configuration of the optical information recording medium to be used can be simplified, and the low level can be achieved. Cost can be reduced. In addition, since it is not necessary to turn the optical information recording medium upside down, it is convenient to use, and a series of information is recorded over two information recording layers.
Use in an unprecedented use mode becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an optical information recording medium applicable to a drive device according to the present invention.

FIG. 2 is a plan view of a main part of the optical information recording medium shown in FIG.

FIG. 3 is a plan view of the optical information recording medium shown in FIG.

FIG. 4 is a configuration diagram of a drive device according to the present invention.

FIG. 5 is a sectional view showing another example of the optical information recording medium applicable to the drive device according to the present invention.

FIG. 6 is a sectional view showing still another example of the optical information recording medium applicable to the drive device according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 optical information recording medium 2 transparent substrate 3 preformat pattern 4 reflective film 5 recording film 11 spindle motor 12 first optical head 13 second optical head 21 protective plate 24 air layer 25 organic dye layer

Claims (1)

[Claims] 1. A drive device comprising: a drive section for an optical information recording medium; and an optical head for optically recording and reproducing information on the optical information recording medium. A first optical head and a second optical head are arranged on both sides of the information recording medium, and one of the two optical heads is formed on the optical information recording medium. A drive device for an optical information recording medium, wherein a tracking error signal of a light beam is detected from the preformat pattern, and tracking control of the two optical heads is performed based on the tracking error signal.