The drive system of the multilayer optical disc with a fixed aberration correction and optimum interlayer distance

 

(57) Abstract:

The invention relates to optical disks, which have multiple information layers. System CD-ROM drive contains a laser light source, an optical disk containing svetopropusknuyu substrate, the first and second information layers, respectively, the film of partially svetopropusknaya material and the film of reflective material covering respectively the first and second information layers, and a translucent intermediate layer located between the first and second information layers, the motor for rotating an optical disc, a lens for focusing the laser beam to a spot having a fixed spherical aberration correction. A feature of the system is that the focused spot is approximately the minimum spherical aberration when it is located in an intermediate layer between the first and second information layers. This allows, when acceptable spherical aberration, increase the thickness of the intermediate layer and to reduce the interlayer interference, and is compatible disk drive with the traditional single-layer information disks. 2 C. and 8 C.p. f-crystals, 8 ill.

Art

Optical data storage systems provide a means of storing large amounts of information. Data access is achieved by focusing the laser radiation to a small spot on the information layer of the optical medium, and further detecting the reflected light beam. The drive system of the optical disk from a removable optical disks are the most common form of optical data storage. There are various types of such systems. In the system ROM (permanent memory), such as the system compact disk (e.g./CD-ROM, CD-audio/CD-video), data in the form of marks are formed on the disk during the manufacturing process without the possibility of further overwriting. Data is detected based on changes in the reflection coefficient of the laser radiation reflected from the information tags. System WORM (write once, read once, read many) allows the user to record information by creating labels, such as grooves, in the recording layer of the optical disk. Information, once recorded on the disc, not street optical data storage system with erasing, such as systems with phase change and magneto-optical (MO) system. Although in systems with phase change data is also read by registration of the change of the reflection coefficient of the laser radiation, in MO systems, data is read by measuring the rotation angle of the polarization plane of the incident wave caused by the impact of the MIS environment.

To increase the capacity of storing information on an optical disc, the proposed system with multiple information layers. Access to different layers of the optical disk with two or more information layers can be done by changing the focal length of the lens. In U.S. patent 5202875 IBM described drive system of an optical disk with multiple information layers in which the optical disk contains a variety of substrates separated by an air gap, or multiple information layers located in the solid-state structure. In U.S. patent 4450553 company U. S. Fhilips used solid-state structure with multiple information layers, where each layer represents the information layer of the CD type. In such systems, optical drive with multiple information layers with whom, to have access to the information layer located on different substrates. When focusing a light beam through a relatively thin substrate transparent to light, it becomes spherical aberration. The lack of correction of the spherical aberration of the light beam prevents the achievement of the spot size close to the diffraction-limited. In the case of known single-disc optical disc drives, such correction can be performed with minor modifications of the surface shape of the focusing lens with a fixed thickness of the substrate, since the thickness of the substrate material, through which must pass the light beam remains unchanged. However, in the optical disk drives with multiple information layers, due to the fact that the desired light beam is focused through a different number of substrates having a certain thickness, depending on which access to the information layer, requires a certain kind of adjustable active correction of spherical aberration. For example, in U.S. patent 5097464, company Matsushita (Matsushita), the described system CD with multiple information layers, which uses the lens aberration correction for delnegro, when the laser spot focused on the information layers located closer to the lens. Also in U.S. patent 5202875 IBM described drive system of an optical disk with multiple information layers with an active compensator aberrations.

An additional disadvantage of systems with multiple information layers is necessary compatibility with the known discs with single information layer, such as CD-ROMs. For example, in the well-known CD-ROMs use the polycarbonate substrate with a thickness of 1.20 mm In the CD-ROM with multiple information layers, it is necessary to provide focusing of the light beam in a spot that is close to diffraction-limited, the information layer of the known disc with single information layer, and on the numerous information layers more modern drives with multiple information layers.

Another disadvantage, which is characteristic for systems with multiple information layers, associated with cross-distortions that arise due to parasitic overlay data, focus error signal and the tracking error from the adjacent information layers, interfering with the useful signals from t the fault, you must have a relatively large distance between the information layers. However, a relatively large gap between the information layers, which are divided between the strips of the solid-state material, increases the total thickness of the disk and the magnitude of the required correction of spherical aberration, which in both cases is undesirable.

In this case, it is necessary that the optical drive was working with disks that have single and multiple information layers, and which would minimize the influence of the spherical aberration and the interlayer distortion.

According to the present invention has developed a system for optical data storage containing a laser light source, an optical information medium, which contains the first information layer that partially transmits light, the second information layer, reflecting light, and an intermediate layer that transmits light and located between the first and second information layers, separating them with each other, the lens located between the laser source and the first information layer of the medium, for focusing the laser beam spot, the lens having a spherical aberration correction, to focus the radiation in the spot, which is approximately the minimum sphericality of the present invention, developed optical information disk of this type, which is read by a laser beam passing through a lens having a spherical aberration correction, containing a substrate transparent to light and having a thickness t1, and the first surface forming the outer surface of the disk that receives the laser beam from the lens, the first information layer that partially transmits light and is located on the surface of the substrate opposite the first surface, the second information layer, reflecting light, and an intermediate layer that transmits light, which has a thickness t2 and is located between the first and second information layers, separated, the thickness t1 of the substrate material plus half the thickness t2 of the material of the intermediate layer equal to the thickness of material corresponding to the above-mentioned aberration correction lens.

According to a third aspect of the present invention has developed a system of optical disc drive that contains a laser light source, an optical disk, which contains (a) a substrate transparent to light and having a first surface forming the outer surface of the disk that receives the laser beam, (b) the first information layer that partially transmits light and is located on powiatowy layer, light and located between the first and second information layers, separated by the value of its thickness, the motor adapted to drive to rotate the disk, a lens located between the laser source and said first surface of the substrate, for focusing the laser beam spot, the lens having a spherical aberration correction, which caused a total thickness of the substrate plus approximately half the thickness of the intermediate layer, and means connected to the lens for moving the lens relative to the disk so that a focused spot could move from one information layer to another information layer, thus to spot located on the first information layer, had a spherical aberration, since the total thickness of the substrate and the material of the intermediate layer, which crosses the beam, less than the thickness of the correction of the spherical aberration of approximately half the thickness of the intermediate layer and being located on the second information layer, the spot had a spherical aberration, since the total thickness of the substrate and the material of the intermediate layer, which crosses the beam, the more the thickness of the correction of spherical aberration will bring the Oia, the developed system of the optical disk, a compact disk (CD) containing the laser light source, optical CD, which contains (a) a substrate transparent to light, having a thickness t1 and a first surface that forms the outer surface of the disk that receives the laser beam, (b) the first information layer that partially transmits light, located on the surface of the substrate opposite the first mentioned surface, (C) the intermediate layer is transparent to light and having a thickness t2 and located on the first information layer, and (d) a second information layer, reflecting light and located on the intermediate layer and separated from the first information layer about the thickness t2, the motor adapted to drive to rotate the disk, a lens located between the laser source and said first surface of the substrate, for focusing the laser beam spot, the lens having a fixed correction for spherical aberration, and means connected to the lens for moving the lens relative to the disk so that a focused spot could move from one information layer to another information layer, a fixed correction sperino-limited, is approximately t1+t2/2 from the first surface of the disk.

According to the fifth aspect of the present invention developed an optical disk for storing information disc type, in which information is read by means of laser radiation passing through a lens having a spherical aberration correction, which corresponds to a fixed thickness of a material transparent to light and having a known refractive index, and the disk includes a substrate, partially transmits light, the first information layer that partially transmits light, the second information layer, reflecting light, and an intermediate layer that transmits light and located between the first and second information layers separated, the thickness of the substrate transmits light, plus half the thickness of the intermediate layer, equal to the fixed thickness of a material transparent to light and having a known refractive index, for which the correction of the spherical aberration of the lens.

In a preferred embodiment of the present invention is designed drive system multi-layer information from an optical disc, which has a fixed correction aberrationally multilayer information disc has a substrate with a thickness which has been reduced by approximately half the thickness of the intermediate layer that separates the first and the last information layers. The disk is adapted for use with a lens that has a spherical aberration correction to compensate for the thickness of a known single-layer information of the disk. This allows the disk drive to work with multi-layer information disks, and also to be compatible and, thus, to work with the known single-layer information disks. For the correction of spherical aberration, the thickness of the substrate material plus half the thickness of the material of the intermediate layer (which may be different from the substrate material refractive index) is equal to the thickness of the substrate material used in known single-layer information to disk. The focused spot with minimal spherical aberration, thus, is rather in the middle of the intermediate layer than the first information layer. The thickness of the intermediate layer are chosen so that the focused spot, which is located on the first or on the last information layer, had given constructive spherical aberration within the acceptable range. As a result, the thickness of the intermediate layer can mn is La the thickness of the substrate and the thickness of the intermediate layer, and then the lens corrects for spherical aberration corresponding to the thickness of the substrate material plus half the thickness of the material of the intermediate layer.

Brief description of drawings

The invention is illustrated by reference to the accompanying drawings, in which:

Fig. 1 depicts schematically the drive system of the optical disk according to the present invention, in the form of CD;

Fig.2 depicts schematically the optical head and the double-layer disc drive system of an optical disk;

Fig.3 depicts a block diagram of a drive system of an optical disk;

Fig. 4 depicts a graph of the intensity of the focused light spot from the transverse distribution of the radiation for two cases: curve A - minimum spherical aberration curve and In - significant spherical aberration;

Fig. 5 depicts a graph of the number of acted for two materials with different refractive indices as a function of distance from the position at which spherical aberration is minimum for lenses with N. A.=45;

Fig. 6 depicts a cross section of a double-layer disc and the light spot with minimal spherical aberration, located in the middle of the intermediate layer;

the mi (the thickness of the intermediate layer) for two systems of optical disc lens with N. A.=0,55, in the first case the spot with minimum spherical aberration is located on the first information layer, and in the other case spot with minimum spherical aberration is located in the middle of the intermediate layer; and

Fig. 8 depicts a cross-section of a two-layer disk with a thin layer of dust and stain with minimal spherical aberration, which is located in the middle of the intermediate layer.

Description of the preferred embodiments of the invention

In Fig. 1 shows a schematic drawing of a system for storing data on an optical disc, which, according to the present invention, denoted overall position 10. The system 10 further referred to as an optical CD. The system 10 includes a disk 12 of the optical data storage, which is mounted for movement on a fixed shaft 14 known in the art by the way. The shaft 14 is attached to the rotating motor 16, which in turn is attached to the chassis 20 of the system. The motor 16 rotates the shaft 14 and the disc 12.

The optical head 22 is positioned under the disk 12. The cylinder 22 is fixed to the bracket 24, which is in turn connected to the drive device, such as a motor 26 of the coil. The number of the lower side of the disk 12.

In Fig. 2 illustrates schematically one preferred implementation of the optical head 22 and the disk 12 (Fig.1). The optical head 22 includes a laser diode 200, which may be a gallium-GA-aluminum laser diode, generating the main beam 22 of the laser beam, the wavelength is approximately equal to 780 nm. The beam 202 is the first ray diffraction grating 201, which in addition to the basic information beam generates two diffraction beam for tracking, and then collyriums lens 203. The resulting three-component beam 204 then passes to an optical divider 205 of the beam. Part of the laser beam 204 after reflection from the optical divider 205 gets on the lens 206 and the optical detector 207. The detector 207 is used for power control of laser radiation 204. The beam 204 extending from the optical divider 205, and then is reflected from the mirror 208. The beam 204 then passes through a focusing lens 210 and is focused into a diffraction-limited spot. Lens 210 is mounted in the holder 214, the position of which is adjustable relative to the disk 212 by means of the motor 216 that controls the focus position, which can be a motor with the voice coil. Move line the focused spot between the two information layers 52 and 62 of the disk 12.

Part of the light beam 204 is reflected from the information layer 52, 62 in the form of beam 220. The reflected beam 220 passes back through lens 210 and is reflected by the mirror 208. The beam 220 is directed to an optical divider 205 through the astigmatic lens 232 and multielement optical detector 234.

In Fig.3 depicts a block diagram of a drive system of an optical disk, which is denoted by the General position 300. Multi-element detector 234 (Fig.2) produces output signals that produce the data signal, the error signal focus (FES) and the error signal tracking (TES). These signals are amplified by means of amplifier 236 signal and fed directly to the controller 314. A peak detector 310 also receives the signal FES, and a peak detector 312 also receives the signal TES from the amplifier 236. The controller 314 also receives the input signal from the peak detector 310 FES, peak detector 312 TES and detector 207 laser power. The controller 314 is a controller of the disk drive based on a microprocessor. The controller 314 is also connected with the ability to control the laser 200, the main motor 206, the motor shaft 16 and the motor 16 of the drive of the focus.

In Fig.2 shows a cross section of the disk 12. The disk 12 contains the 40 turned his face to the lens 210 and is the side towards the light, which falls on it. The opposite surface of the substrate 40 formed on the first information layer 52. Information layer 52 is a control layer with grooves or recesses, which are formed on the surface of the substrate 40 and is covered with a film made of a material that partially transmits light. Information layer 52 is formed using a known method, injection molding, extrusion or injection molding using a photopolymer. The substrate 40 and the first information layer 52 is similar to the known CD-ROM, except that the film covering the control sample of grooves on the surface of the substrate partially transmits the light to a greater extent than reflects. This film or the material can be made of any known semiconductor material (for example, amorphous Si, SiC, GaSb), dielectric materials (e.g., ZrO2SiN) or metallic materials (for example, Al, Au). These materials can be obtained in the form of a deposited layer by means known in the art methods, sputtering or evaporation with a thickness of about 30-3000 angstroms. The intermediate layer 44, which transmits light is formed on the information layer 52. The intermediate layer can be formed from fotop is 44 can be formed in the rolling process, that is, by bonding a thin plastic sheet that hottinen information layer 62, a film coating information layer 52 located on the substrate 40. The surface of the intermediate layer 44 opposite the surface that is in contact with the information layer 52 formed on the second information layer 62. Information layer 62 also contains a control sample of grooves formed on the surface of the intermediate layer 44, and a film coating of reflective material such as aluminium alloy. Film coating of aluminum alloy is preferably fully reflecting if the information layer 62 is the latest information layer of the multiple information layers of the disk and has a typical thickness of about 100 to 1000 angstroms. Embossed pattern information layer 62 can be formed in the process of photopolymerization using the matrix in contact with the polymer that is heat treated using ultraviolet radiation. If the intermediate layer is formed by rolling, the information layer 62 can be pre-push on the plastic sheet before applying the adhesive sheet to Pocatello, the protective layer 70 of the photopolymer is formed on the information layer 62 using a circular rotation, followed by heat treatment. Dual layer CD (Fig.2) is a disc with two information layers. The substrate 40 has a thickness t1 and is made of svetopropusknaya material with refractive index n1. The intermediate layer 44 has a thickness t2 and is made of svetopropusknaya material n2. In the disk 12 can be used for more information layers. For example, additional samples and pushed film, partially transmits light, can be formed between the first and second information layers 52 and 62.

Below will be described the operation of the optical storage system 10 (Fig.1) with reference to Fig.2 and 3. The controller 314 controls the motor 16 which rotates the disk 12 and the motor 26, which moves the optical head 22 in the correct position on the lower side of the disk 12. The laser 200 is introduced into working condition for reading information from the disk 12. Beam 214 is focused by lens 210 in the spot, close to the diffraction divergence, and is focused spot is located at a desired one of the information layers 52 and 62. The reflected beam 220 comes back and goes to Sa detector 234 and amplified by means of amplifier 236 (Fig.3). Signal FES is used by the controller 314 in the known method of servo control for controlling the motor 216 of the actuator to the lens 210 focuses the beam in the desired spot on the information layer (for example, the information layer 52 during rotation of the disk 12. When data must be read from the information layer 62, the controller 314 generates a signal for engine 216 drive the focus to move the lens, and hence the spot from the information layer 52 in the information layer 62, when the light beam passed through the lens 210 intersects the interior of the substrate 40 with a thickness t1 and the intermediate layer 44 with a thickness of t2.

In the drive system of the optical disk is also necessary to have the diameter of the focused spot as possible and to have a minimum spherical aberration. Because the light is focused through the substrate, the refractive index and the thickness of the substrate must be taken into account in the design of the lens lens. The lens design so that the spherical aberration correction would be consistent with a fixed thickness of a material transparent to light and having a known refractive index. In Fig.4 presents a graph of the dependence of the radiation intensity of the focused light is ical aberration and in another case with significant spherical aberration due to the optimum thickness of the substrate. Curve A (Fig.4) corresponds to the spot with minimal spherical aberration and actually has a Gaussian intensity distribution of the light beam. The diameter of the diffraction-limited spot is defined as the width of the distribution at the level of 0.5 of the maximum amplitude of the intensity and is shown in curve A (Fig.4). The curve In (Fig. 4) corresponds to the spot with a spherical aberration and represents the lowest maximum intensity and the presence of side lobes. In the optical disc drive if the lens has no correction in accordance with the correct thickness of the substrate, the spot on the information layer will have spherical aberration. This is undesirable, because all of the data signals, focus error and tracking error affect the optical resolution at maximum.

The ratio of maximum intensity spot with aberration to the maximum intensity of the spot of radiation with a divergence close to the diffraction, without aberration, is called the number of acted. Fig.5 depicts a graph of the number of acted, as a function of the thickness variation of a substrate on which the lens for two materials having different indexes of refraction for lenses with N. A.=0,45. The continuous line represents the Chi is dstanley a number of acted as for the material, which has a refractive index of 1.10. When the deviation of the thickness is close to zero, the light is shifted at a precise distance for which the lens has a spherical aberration correction, the number of acted theoretically equal to 1.0. However, if a light beam passes through the material, the stain will have spherical aberration. In the case of known CD system with n=1.57 and the lens having a numerical aperture N. A. =0.45, and the minimum number of acted is ~ 0.9. This corresponds to a deviation of the thickness of the material is approximately +/gel-0.125 mm For a system with two-layer data, as discussed and described in Fig. 2, this means that if the intermediate layer 44 is also a material with a refractive index close to 1,57, the intermediate layer may not be thicker than about 0.125 mm, or the stain will have unacceptably high spherical aberration when it is focused on the information layer 62. For lenses with N. A.=0,55 with the same requirement for the ratio of the number of acted as 0.9, the thickness of the intermediate layer, can not be more than about 0.05 mm, Thus, the problem of spherical aberration in the drive systems of the multilayer optical disc is solved by creating about Novocainum optical disks are interlayer distortion from the adjacent information layers in case when the spot is located at a desired information layer. This disadvantage is eliminated better by creating an intermediate layer more thick.

In the present invention the drive system of the multilayer optical information disk means that the focused spot with minimum spherical aberration is not located on the information layer, and preferably, at the midpoints between two successive layers, and further from the lens. In the case of the drive system of the optical disk is a CD with two layers (Fig. 2), a disk drive manufactured so that the stain with minimum spherical aberration was located in the middle of the intermediate layer 44.

Thus, the focused light spot (Fig.6) with minimum spherical aberration is depicted as located approximately in the middle of the intermediate layer 44 (i.e., t2/2 distance from both layers 52 and 62 of the data). The thickness of the material, which is traversed by the light beam at this point, approximately equal to the thickness t1 of the substrate 40 with a refractive index n1 and a half of the thickness of the intermediate layer 44 (t2/2) with refractive index n2. In a preferred embodiment, the lens 210 podobny substrate made of polycarbonate (n=1,57), equal to 1.20 mm, However, in the preferred embodiment, the substrate 40 has a thickness not equal to the known thickness of the substrate, but is equal to a known thickness, which is t2/2 the thickness of the intermediate layer 44. In the embodiment, a CD of the present invention with a lens having a value of N. A.=0,45 thickness t1 of the substrate 40 is approximately 1,075 mm and the thickness t2 of the intermediate layer 44 is approximately 250 mm For lenses with a value of N. A. = 0,55 thickness t1 of the substrate 40 will be approximately 1.15 mm, and the thickness t2 of the intermediate layer 44 will be approximately 0,10 mm the Material of the intermediate layer 44 is preferably a polymer that has a refractive index very close to the refractive index of polycarbonate, what is the effect of the second order correction of spherical aberration and not a necessary factor in the choice of the thickness t1 of the substrate, however, if the refractive index of the intermediate layer is different from the refractive index of the substrate, the thickness t1 of the substrate is adjusted so that the thickness t1 of the substrate material with a refractive index n1 and the thickness t2/2 of the material of the intermediate layer with a refractive index n2, along the well t2 of the intermediate layer 44 is chosen based on the minimum number of acted, which in turn depends on N. A. lens and the refractive index of the substrate material. The thickness t2 is chosen so that t2/2 corresponded to the maximum change in thickness, which is still spherical aberration. For a CD with two-layer data with N. A. equal to 0.45, and is t2/2 = 0.125 mm (the number of acted as equal to 0.9) or t2= 0,250 mm the result is a doubling of the thickness of the intermediate layer in comparison with that which will be the case if the focused spot with minimum spherical aberration is placed on the first information layer. The effect of interlayer interference is significantly reduced, although the magnitude of spherical aberration on both information layers still has a place.

The advantage of this variant implementation of the present invention is that because the lens remains with the spherical aberration correction for a known thickness of the substrate of the optical disk with a single information layer, the optical disk can also work with well-known single-layer information disk. Thus, in the case of the drive system of the optical CD drive works with double-layer information disk (the thickness of the substrate t1=1,75 mm and the thickness of the intermediate is an alternative embodiment of the present invention the thickness of the substrate and the intermediate layer is chosen with the possibility of optimization of process of manufacturing a multilayer information disc and the lens has a spherical aberration correction for the selected thickness t1 of the substrate with a refractive index n1, and the thickness t2 of the intermediate layer with refractive index n2. In the case of a CD-ROM drive, a known substrate with a thickness equal to 1.20 mm, can be used for systems with two-layer data and the intermediate layer may have a thickness of 0.250 mm Lens will continue to adjust to 1,325 mm [1,20 (t2/2= 0,125)] material (believing N. A.=0.45 and the intermediate layer izgotovlivajut from a material with a refractive index close enough to 1,57 in order to have an insignificant effect of spherical aberration).

The method of correction lenses for the well-known spherical aberration in systems having flat parallel to the substrate, is a well-known technique. The wavelength of the light beam and the refractive index of the material through which the light must pass, used to generate a polynomial equation that represents the shape of the lens. This method is described, for example, R. Kingslake in the "design Basics lenses" (R. Kingslake, "Lens Design Fundmentals", pp. 119-122 and 205-208, Academic press, 1978), and which is not part of the present invention.

In Fig. 7 depicts an enlarged gap size information layer, which is achieved in the present invention for lenses with N. A.=0,55. For example, when N. A. =0.55 and opustynennoe spherical aberration, located on the first information layer, shows that the intermediate layer may not be thicker than about 0,065 mm However, using the present invention, where the drive system is designed so that the spot with minimum spherical aberration was located in the middle of the intermediate layer, the thickness of the intermediate layer can be doubled to 0.13 mm In the preferred invention uses the number of acted, equal to 0.9. However, may require a higher or lower values of the ratio of the number of acted, depending on the specific parameters of the drive system drives, such as N. A. lens and the refractive index of the substrate and the intermediate layer.

In Fig. 6 depicts a system with a multilayer information disc as a solid structure, where the outer layers represent the substrate 40 and the protective layer 70. In case of CD, the substrate 70 is a polycarbonate with a thickness of 1.20 mm 1.20 mm less than the thickness of 2t/2 depending on the implementation. However, the disc with multi-layer data may be produced by combining two internal drives with a single layer of data. In this type of structure, the protective layer 70 is a second substrate, identical will fit combined together with material transmits light, such as known photopolymer, which in this case serves as an intermediate layer. Information layer nearest the substrate to the lens 210 has a film coating that partially transmits light, over his sample of slots, and an information layer located on the nearest from the lens substrate 210 has a General film with a coating that reflects light on its sample of fill.

Fig. 8 depicts the invention with an alternative type of multilayer information disc 90. The disk 90 includes a workpiece 91 aluminum drive, closest to the lens 210 information layer 92 formed on the workpiece 91 disk, the intermediate layer 93, located on the information layer 92 and the closest to the lens 210 information layer 94 formed on the intermediate layer 93. The plastic ring 95 is connected with the workpiece 91 aluminum disk and located on the perimeter of the workpiece 91 disk. The ring 95 protects the transparent plastic coating 96 from dust. Floor 96 of dust usually has a thickness of about 100 μm and is across and is connected with the ring 95. Protective coating 96 forms an air gap equal to 0.2 - 2.0 mm between it and the information layer 94. Both information layers 92 and 94 are information shall include the layer 94 has a thickness of, equal to 60 to 120 angstroms, and is, thus, due to its thickness, partially transmits light. The most far located from the lens 210 of the second information layer 92 has a thickness of 400 to 2000 angstroms, and thus has an increased reflectivity of the information layer 94. The intermediate layer 93 has a circular floor and is heat treated polymer films with a typical thickness of 0.5 to 0.15 mm, a Focused spot with minimum spherical aberration is located in the middle of the intermediate layer 93 (Fig.8). In this embodiment of the invention matte, through which passes the light to the information layers 92, 94 is coated 96, protecting from dust. Thus, the spherical aberration correction for lens 210 is a correction necessary due to the passage of the light beam through the thickness of the anti-dust cover 96 (with its refractive index n1) and through half the thickness of the intermediate layer 93 (with its refractive index n2). Passing a light beam through the air does not introduce additional spherical aberration, as the air gap between the anti-dust coating 96 and the first information layer 94 does not make much noticeable distortion in cartilage can be used there, using additional information layers located between the first information layer (closest to the lens information layer) and the second or the last information layer (farthest from the lens information layer). For example, in vosmisloyny information disk, where the intermediate layer corresponds to the thickness between the nearest and farthest information layer, the drive will be constructed so that the lens had a spherical aberration correction for t1+t2/2, where t2 is the thickness of the solid material transparent to light, between the closest and farthest information layer) and stain with radiation, with close to the diffraction divergence, will be located between the fourth and fifth information layer relative to the lens.

The invention is described in relation to system CD. However, the invention can fully be used with any multi-layer optical information disc, such as magneto-optical, phase change or drives with a single write once, read many (WORM).

1. The drive system of the optical drive that contains a laser light source for generating laser radiation, an optical disk containing setproperties is built on the surface of the substrate opposite the first surface, film of partially svetopropusknaya material covering the first information layer, a second information layer, the film of reflective material covering the second information layer, and a translucent intermediate layer located between the first and second information layers, separating them on their thickness, the motor for rotating an optical disc, a lens located between the laser source and the first surface of the substrate disk, for focusing the laser beam spot, and the lens has a spherical aberration correction with the correction value corresponding to a fixed thickness svetopropusknaya material, characterized in that the focused spot is approximately the minimum spherical aberration, when it is located in an intermediate layer between the first and second information layers.

2. The system under item 1, characterized in that the fixed thickness svetopropusknaya material, which corresponds to the amount of correction of spherical aberration of the lens, essentially equal to the thickness of the substrate plus approximately half the thickness of the intermediate layer, and means connected to the lens for moving the lens relative to the disk in the Yes spot is located on the first information layer, it has a spherical aberration, since the total thickness of the substrate and the intermediate layer, which is traversed by the light, less than the thickness of the material corresponding to the amount of correction of spherical aberration, approximately half the thickness of the intermediate layer, and when the spot is located on the second information layer, it has a spherical aberration, since the total thickness of the substrate and the intermediate layer, which is traversed by the light, greater than the thickness of the material corresponding to the amount of correction of spherical aberration, approximately half the thickness of the intermediate sdoa.

3. The system under item 2, characterized in that the fixed thickness svetopropusknaya material corresponding to the amount of correction of spherical aberration of the lens, essentially equal to the thickness tl of the substrate of refractive index n1, while the disk substrate made of a material having a refractive index n1 and a thickness of approximately tl-t2/2, where t2 is the thickness of the intermediate layer.

4. The system under item 2, wherein the substrate is a disk made of a material having a refractive index n1 and a thickness of approximately t1, and the intermediate layer is made of a material having a coefficient of prelamin which corresponds to the amount of correction of spherical aberration of the lens, essentially equal to the thickness t1 of the substrate material plus the thickness t2/2 of the material of the intermediate layer.

5. The system under item 2, characterized in that the fixed thickness svetopropusknaya material, which corresponds to the amount of correction of spherical aberration of the lens is approximately 1.20 mm polycarbonate, while the disk substrate made of polycarbonate and has a thickness of approximately 1.20 mm minus half the thickness of the intermediate layer.

6. The system under item 2, characterized in that the fixed thickness autoproducido material, which corresponds to the amount of correction of spherical aberration of the lens is approximately 0,60 mm polycarbonate, while the disk substrate made of polycarbonate and has a thickness of approximately 0,60 mm minus half the thickness of the intermediate layer.

7. Optical disk for storing data read by a laser beam passing through a lens having a spherical aberration correction, containing svetopropusknuyu substrate having a first surface that receives the laser beam, the first information layer located on the surface of the substrate opposite the first surface, the film is partially the reflective material, covering the second information layer, a translucent intermediate layer located between the first and second information layers and separating them on the thickness svetopropusknaya intermediate layer, characterized in that the thickness of the translucent substrate plus half the thickness of svetopropusknaya intermediate layer essentially equivalent to the thickness svetopropusknaya carbonate corresponding to the amount of correction of spherical aberration of the lens.

8. The optical disk under item 7, characterized in that the thickness of the translucent substrate plus half the thickness of svetopropusknaya intermediate layer essentially equal to 1.2 mm

9. The optical disk under item 7, characterized in that the thickness of the translucent substrate plus half the thickness of the intermediate svetopropusknaya layer is essentially equal to 0.6 mm

10. Optical drive one from p. 8 or 9, characterized in that the surface of the second information layer, remote from the intermediate layer is a protective layer.

 

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The invention relates to optical storage media

The invention relates to a storage medium containing a fluorescent layer located on the substrate, where the supporting information structure is provided in the fluorescent layer in its surface or on the surface and to the substrate, and where carrying the information structure is provided on a straight-line or curved path, or in rows, or columns so that the bearing information of the structure to form a matrix, and where the fluorescent layer mainly contains molecules of a fluorescent dye embedded in a transparent polymer substrate material

The invention relates to optical data storage devices

The invention relates to techniques for gathering information

The invention relates to a system platinumblack materials for use in a magneto-optical recording and aimed at the realization of a direct overwrite with power modulation of the laser radiation

The invention relates to a system for transmitting audio and/or video information, such as encoded audio or encoded video

Optical sensor // 2179750

The invention relates to optical recording and can be used for high-speed recording, playback and store large amounts of information

FIELD: optical data carriers.

SUBSTANCE: optical scanning device for information carrier has emission source, collimator lens assembly, objective lens assembly and drive for moving assembly of collimator lens, drive has moving and immovable portions, movement of which relatively to each other is limited, while immovable and moving portions of drive are in the same magnetic circuit, having immovable magnetizable portion contained in moving portion of drive, aforementioned first and second positions of which are balanced positions. Device is made with possible control by means of adjustment of electric current by interaction between electromagnetic field of inductiveness coil and magnetic field of constant magnet.

EFFECT: possible production of reliable and functional drive for moving collimator assembly.

2 cl, 5 dwg

FIELD: physics.

SUBSTANCE: near-field optical head has a slider which holds a light source and a scattering element. The scattering element has a plane lying on the side of the light source almost perpendicular to the recording medium. The end of the scattering element generates near-field light and propagates it onto the recording medium.

EFFECT: miniaturisation of the near-field optical head.

14 cl, 15 dwg

FIELD: information technologies.

SUBSTANCE: device comprises a lens of spherical aberration correction, having one surface shaped with a larger curvature compared to the other surface; and a sliding part that slides along a guide element. The protruding part of the sliding part is configured so that it is installed within the limits of the side surface of the reflective surface of the upward reflecting mirror, and a part of the spherical aberration correction lens protruding away from a lens holder, is applied onto the reflective surface of the upward reflecting mirror, when the lens of the spherical aberration correction is approaching the upward reflecting mirror as close as possible.

EFFECT: reduced dimensions of the device and increased range of spherical aberration correction.

15 cl, 8 dwg

FIELD: physics.

SUBSTANCE: optical head device includes a diffraction element which is divided into three regions. Phases of the grating of the left and right hand regions of the diffraction element for generating an additional beam differ from each other by 180 degrees. The central region of the diffraction element for generating an additional beam has a grating structure which differs from the structure of the left and right hand region, and divided into multiple regions to form different gratings which are different from each other.

EFFECT: use of a single diffraction element for discs with different track spacing to obtain a tracking error signal and preventing the fall of the amplitude value of that signal.

36 cl, 24 dwg

FIELD: optical data carriers.

SUBSTANCE: optical data carrier has at least two layers, each of which is a substrate with recording film, on which optically discernible code relief is formed with information elements readable via laser radiation, which contain elements with optical limiting property. Method for manufacture of optical multilayer data carrier includes manufacture of at least two layers, each of which has optically discernible code relief with laser radiation readable information elements, which are formed of substance, having property of optical limiting. Method for multilayer optical recording of data, in which information is recorded by forming and moving pulses of laser radiation flow along surface of recording film in formed tracks, filled with substance, having optical limiting property, or components for synthesis of substance, having property of optical limiting. Method for reading from optical multilayer data carrier, including forming of laser radiation flow, its focusing at read layer with optically discernible code relief with information elements, containing substance, having property of optical limiting, modulation of light signal reflected from code relief by frequency and amplitude.

EFFECT: higher efficiency.

4 cl, 3 dwg

FIELD: data carriers.

SUBSTANCE: in optical data carrier, including track, including multiple recesses, formed on basis of first data being subject to recording, and platforms, formed between adjacent recesses, these recesses are recorded with deformation on basis of second data. First and second data are synthesized and played for realization of sound playback with broad frequency range. Also, first data are recorded with possible playback by means of common disc player. Playback of first data is controlled by second data for protection of recorded data.

EFFECT: higher efficiency.

6 cl, 44 dwg

FIELD: optical data carriers.

SUBSTANCE: device has cation dye or mixture of cation dyes with optical characteristics, changed by means of recording beam, an at least one substance with functions of damper and phenol or substituted phenol with one hydroxide group or more, while it additionally contains phenol or substituted phenol in form of phenolate ion, forming a portion of anions for dye cations, as a stabilizer. Data carrier can contain anionic metal-organic thyolene complex as damper, which forms other portion of anions for dye cations.

EFFECT: higher stability, higher durability, lower costs.

5 cl, 1 tbl, 3 ex

FIELD: optical data carriers.

SUBSTANCE: device has tracks, each of which is comprises multiple recesses, formed on basis of first data, meant for recording, and areas between recesses. Multiple recesses are displaced from track center on basis of second data, at the same time recesses cross central position of track with given periodicity. First data may be recorded analogically to compact disk data. Second data may be separated from signal of track tracking error. Second data may be used for copy protection in relation to first data, while amount of first data, which can be recorded on carrier, does not decrease when recording second data, and as a result of recesses displacement range being set within limits of preset value in range, wherein no track tracking displacement occurs, first data can be played back by existing players to provide for compatibility of playback.

EFFECT: higher efficiency.

8 cl, 12 dwg

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