Abstract: A method for fabricating an optical recording medium is provided. A dye layer is formed on a molded substrate by spin-coating. A reflection layer is formed on the dye layer by sputtering so that the optical disc has enough reflection rate. The dye layer comprises a cyanine type dye and an azo metal chelate compound selected from the formula (I): wherein M is a metal ion; R1 is a hydrogen atom, a linear or branched alkyl group containing 1 to 6 carbon atoms, amino group, alkyl amino group or toluidinyl group; R2 is a hydrogen atom, a hydroxyl group, a halogen atom, an ether group, an ester group or a linear or branched alkyl group containing 1 to 6 carbon atoms; R3 is a hydrogen atom or a linear or branched alkyl group containing 1 to 6 carbon atoms; R4 is a hydrogen atom, a halogen atom or a linear or branched alkyl group containing 1 to 6 carbon atoms; A1 is a heterocyclic derivative group constituted by carbon atoms and nitrogen atoms.

Abstract: In an optical disk including at least a rewritable phase change material and comprising a recording layer having a reflectivity of more than 15%, an address output value as an address pit signal component occupying in a reproduced signal in a non recording state is prescribed to be 0.18 though 0.27 or a numerical aperture of an address pit signal occupying in a reproduced signal in a non recording state is prescribed to be more than 0.3.

Abstract: An information recording method including irradiating a phase change recording layer of an optical recording medium with either a multi-pulse laser light train having a recording power of Pw or laser light having an erasing power Pe to record a mark having a length nT in the recording layer, wherein n is an integer of from 3 to 14 and T represents a clock cycle, wherein the multi-pulse laser light train has a constitution such that a heating pulse and a cooling pulse are alternated and the number of heating pulses and the number of cooling pulses each increases by 1 when n increases by 2, and wherein when n is from 6 to 14, the last heating pulse and last cooling pulse have a pulse width of from 0.5T to 0.9T and from 0.7T to 1.5T, respectively.

Abstract: When a wavelength of a first laser beam with which a first recording medium including a first recording layer is recorded and reproduced is indicated as ?1 (nm), a wavelength of a second laser beam with which a second recording medium including a second recording layer is recorded and reproduced as ?2 (nm), the relationship between the wavelength ?1 and the wavelength ?2 is set to be expressed by 10?|?1??2|?120. The first recording layer has a light absorptance ratio of at least 1.0 with respect to the wavelength ?1. The light transmittance of the first recording medium with respect to the wavelength ?2 is set to be at least 30 in both the cases where the recording layer is in a crystal state and in an amorphous state. In order to record and reproduce the optical multilayer disk with the above-mentioned characteristics, a multiwavelength light source with the following configuration is used.

Abstract: A recording medium comprises a substrate and a recording layer overlaid on the substrate. The recording layer comprises a material, which has properties such that, when recording light having a predetermined wavelength ?1 is irradiated to the material, the material is capable of being caused to change into a fluorescent material and such that, when excitation light having a wavelength ?2 is then irradiated to the thus formed fluorescent material, the fluorescent material is capable of being caused to produce fluorescence. The wavelength ?1 of the recording light and the wavelength ?2 of the excitation light may be identical or different. The substrate may be constituted of a material having properties such that, when the excitation light is irradiated to the material, the material does not produce fluorescence having a wavelength identical with the wavelength of the fluorescence produced by the fluorescent material.

Abstract: An example data storage medium includes an optical information carrier which comprises a polymer carrier, which is set up to store information, and, additionally, a layer. The layer comprises a dye and can be optically changed locally for the purpose of storing information.

Abstract: A magneto-optical storage medium that protects against the effects of cross-talk, making it possible to further reduce the level of track density, and which also makes it possible to conduct high-density recording/playback with a reduced magnetic field for erasure and a favorable level of playback signal quality. More specifically, a magneto-optical storage medium, which includes at least the following laminated layers, in the following order: a playback layer, a non-magnetic layer, a transfer layer, a cut-off layer, and a recording layer. The playback layer preferably displays easy in-plane magnetization characteristics within the monolayer at room temperature, and the transfer layer and the recording layer each have easy magnetization characteristics in the vertical direction of the monolayers at room temperature when each layer is considered as a monolayer.

Abstract: A phase-change optical information recording medium in which information can be recorded, reproduced and rewritten and which includes a first transparent substrate having a wobbling guide groove which is spirally formed thereon at a pitch; a first dielectric layer located overlying the first transparent substrate and having an optical thickness of from 80 nm to 200 nm; a phase-change recording layer located overlying the first dielectric layer and having an optical thickness of from 20 to 50 nm when the recording layer is in an erased state; a second dielectric layer located overlying the recording layer and having an optical thickness of from 10 nm to 70 nm; a reflection layer located overlying the second dielectric layer; optionally a third dielectric layer located between the second dielectric layer and the reflection layer; and a second transparent substrate located overlying the reflection layer.

Abstract: An information recording medium includes a first information layer and a second information layer. The first information layer includes a first recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by irradiation of a laser beam or application of current. The second information layer includes a second recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by the irradiation of the laser beam or the application of the current. The first recording layer is made of a first material, the second recording layer is made of a second material, and the first material is different from the second material.

Abstract: A method and system for providing copy-protected optical medium using a substrate having information stored thereon in information pits and information lands, wherein the information lands comprise lands in two different planes.

Abstract: An optical data recording and storage medium that includes a reflective layer formed from a silver alloy that contains, in addition to silver, about 0.2 to about 1.0 wt. %, based on the total weight of alloy, of samarium (Sm), about 0.2 to about 2.0 wt. % of copper (Cu), about 0.1 to about 0.3 wt. % of titanium (Ti), and about 0.2 to about 0.8 wt .% of manganese (Mn).

Abstract: This invention relates to a read-only near-field optical disk using a zinc-oxide (ZnO) nano-structured thin film as the localized near-field optical interaction layer. This read-only near-field optical disk is a multi-layered body at least comprising; (a) a transparent substrate with pre-recorded pits or marks; (b) a reflection thin film; (c) a zinc-oxide (ZnO) nano-structured thin film which is capable of causing localized near-field optical interactions; (d) a first and a second protective and spacer layers formed above or below the localized near-field optical interaction layer, which are also made of transparent dielectric material. Ultrahigh density near-field optical readout can be achieved by localized near-field optical interaction between the zinc-oxide (ZnO) nano-structured thin film and the reflection layer on pre-recorded structure.

Abstract: A rewritable data storage using a carbonaceous material writes or erases information represented by the carbonaceous material by means of a current induced electrochemical reaction on a conductive layer, by controlling a voltage applied across the space between a cantilever tip and the conductive layer. Also, the size of the carbonaceous material representing information is controlled by the level of the applied voltage or the application duration.

Abstract: The invention discloses new benzoindole styryl compounds and its use for a high-density optical recording medium. The invention uses the dyes of the new benzoindole styryl compounds to form the recording layer of high-density recording media. The new benzoindole styryl compounds are easy to prepare and purify, so they are cheaper when comparing to the compounds generally used in high-density optical recording media. The benzoindole styryl compounds has a maximum absorption for the light wavelength in the range of 500 nanometers to 700 nanometers. The benzoindole styryl compounds also have high sensitivity and chemical stability for light and heat. Using the new benzoindole styryl compounds to form a high-density optical recording medium can match up with the short-wavelength laser beam for high-density optical recording media and have the advantage of a stable quality.

Abstract: At least one information layer including a recording layer contains a material that can exhibit a transition between two optically different states in response to irradiation with a laser beam as a main component is provided on a substrate, and the material is configured so as to exhibit an energy gap ranging from 0.9 eV to 2.0 eV in the amorphous state. The information layer is configured to have a light transmittance of not less than 30% when irradiated with a laser beam having a wavelength ranging from 300 nm to 450 nm. It is possible to achieve excellent recording/reproduction, even if a plurality of recording layers are provided in the recording medium, when this medium is irradiated with a laser beam with a wavelength in the foregoing range from one side of the medium.

Abstract: The present invention provides an optical recording medium including a recording layer and an optical reflection layer formed on a substrate. The recording layer contains at least one particular polymethine pigment selected from polymethine pigments having 1 to 4 carbons in the methine main chain, so as to obtain a sufficient recording sensitivity for a red wavelength range of light.

Abstract: According to the present invention, there is provided an optical recording medium including at least an information recording layer and a reflective film in which the reflective film is comprised of an AgCu alloy thin film containing Cu the content of which is greater than or equal to 3.0 [atomic %] and less than or equal to 6.5 [atomic %]. Thus, the optical recording medium can be made inexpensive and weather resistance of the optical recording medium can be improved, thereby making it possible to avoid characteristics of the optical recording medium from being deteriorated even after it has been stored for a long time.

Abstract: An optical recording medium includes a) a dielectric layer, b) a recording layer, and c) a reflective layer, which are stacked on a surface of a substrate in the described order or stacked on the surface in the order of b) the recording layer, a) the dielectric layer, and c) the reflective layer. The recording layer contains a mixed nickel oxides which decomposes to release a gas and becomes transparent upon heating.

Abstract: A recordable digital video disc preferably employable for information recording method using a laser beam having a wavelength of 600–700 nm, composed of a transparent disc substrate provided with a spiral pregroove, a recording dye layer placed in the pregroove, and a light-reflecting layer, arranged in order, wherein the recording dye layer has a thickness in the range of 40% to 90% of a thickness corresponding to an optical path which gives the first minimum reflectance, the optical path giving the first minimum reflectance being determined from a reflectance curve which is prepared using recordable digital video discs composed of the same disc substrate, the same recording dye layer having varying thickness, and the same light-reflecting layer.

Abstract: An element for steering electromagnetic beams. The element includes a phase change material in combination with dielectric and other layers in a multilayer optical stack. The phase change material that is reversibly transformable between two or more structural states, where different structural states differ with respect to refractive index and/or extinction coefficient. The structural state of the phase change material establishes a phase angle state for the element that dictates the direction of propagation of an output beam produced from an incident electromagnetic beam. Depending on the structural state, the element adopts one of two principal phase angle states and a binary beam steering capability is achieved in which an incident electromagnetic beam can be redirected in either of two directions. In a preferred embodiment, the output beam is a reflected beam and the element includes a phase change material sandwiched between two dielectric materials and supported by a metal layer.

Abstract: An optical recording material which when exposed to actinic radiation produces a change in optical properties in the exposed regions, thereby providing a pattern of intelligence for storing and retrieving information, the recording material having: a) a polymer containing a covalently bound reactant moiety which is capable of undergoing a chemical transformation upon a one electron oxidation, thus causing the change in optical properties in the exposed regions; and b) a sensitizer capable of absorbing actinic radiation to cause an initial one electron oxidation of the reactant.

Abstract: Constructed is an optical recording medium which is so formed as to have excellent surface flatness and with respect to which information is recorded or reproduced with the use of a near-field optical system. The optical recording medium is one which performs at least one of recording and reproduction of information by irradiation of light. The optical recording medium has a substrate 1 which has fine concavities and convexities 2 formed on the surface on a side where irradiation of light is performed, and a formed film layer having at least a recording layer and having a fine concavities and convexities surface reflecting the fine concavities and convexities 2 in itself.

Abstract: A multi-layered optical disk comprising a plurality of recording layers accumulated in the thickness direction wherein a light bean is focused on one of tracks of one of the layers thereby to record and reproduce data, the optical disk being characterized in that recording layers each have an identification section storing an address of the recording layer which the identification section belongs to.

Abstract: A method and system for providing copy-protected optical medium using transient optical state change security materials capable of changing optical state when exposed to a wavelength of about 630 nm to about 660 nm and software code to detect such change in optical state.

Abstract: A disk cartridge in which a disk is loaded is formed with composite synthetic resin including at least two types of thermoplastic resin, an anti-static polymer, and an inorganic filler, heat-deforming temperatures of at least two types of the thermoplastic resin mutually differing. The disk cartridge is provided by a method comprising the steps of mixing at least two types of thermoplastic resin to provide a mixture, heat-deforming temperatures of at least two types of the thermoplastic resin mutually differing, mixing an inorganic filler with a mixture of at least two types of the thermoplastic resin, mixing an anti-static polymer with the mixture of at least two types of the thermoplastic resin including the inorganic filler to provide a composite synthetic resin, injection molding the composite synthetic resin to provide component parts of the disk cartridge, and assembling the component parts to form the disk cartridge with the disk loaded therein.

Abstract: An information recording medium capable of high-density recording and accurate reproduction and also capable of repeated recording and reproduction, an information recording device that employs the information recording medium has a Co—Si oxide thin film 1 constructed such that columnar crystals 2 are separated by an intergranular phase 3 which contains SiO2 having a lower coefficient of thermal conductivity than the columnar crystals 2. Therefore, the intergranular phase 3 prevents heat transfer from one columnar crystal 2 to another. In addition, the intergranular phase 3 separates columnar crystals 2 from each other, so that the crystalline structure of each columnar crystal 2 is not affected by its adjacent columnar crystal 2.

Abstract: An optical information recording medium of this invention includes a substrate, a light incident surface, a first reflecting layer formed between the substrate and the light incident surface, a second reflecting layer formed between the first reflecting layer and the light incident surface and stacked on the first reflecting layer, the second reflecting layer being made of the same material as that of the first reflecting layer, and a phase change optical recording layer formed between the second reflecting layer and the light incident surface, the phase change optical recording layer transiting between a crystal state and an amorphous state when irradiated with a light beam.

Abstract: An information recording medium wherein an optically detectable information recording medium is comprised of at least a substrate, a recording layer, and a resin layer. The information recording medium has surface roughness R? on the surface of the recording layer, which is in contact with the resin layer, under 5 nm. The information recording medium controls the reproduction signal noise, enables highly densified recording.

Abstract: In an optical disk including at least a rewritable phase change material and comprising a recording layer having a reflectivity of more than 15%, an address output value as an address pit signal component occupying in a reproduced signal in a non recording state is prescribed to be 0.18 though 0.27 or a numerical aperture of an address pit signal occupying in a reproduced signal in a non recording state is prescribed to be more than 0.3.

Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing uneven initialization due to light interference caused at the time of initialization without deterioration of information recording/reproducing signal characteristics of the recording layers is provided.

Abstract: Disclosed is an optical recording medium comprising a recording layer. The recording layer contains: a charge generation material generating an electron and a hole by light irradiation; a charge transport material transporting one of the electron and the hole; a charge trap which traps the transported one of the electron and the hole to separate the electron and the hole; and a non-linear optical material which changes optical properties of the recording layer in accordance with electric field formed by the electron and the hole being separated from each other. The non-linear optical material has an asymmetrical carbon atom and a cyclic group. Or, it is a cyclic-group-containing constituent having: an inversion symmetric pi-electron system; at least one of an electron donating group and an electron accepting group which are bonded to the inversion symmetric ?-electron system; and an asymmetrical carbon atom.

Abstract: In one embodiment, a holographic data storage medium includes a substrate, a holographic recording material, and an optically detectable tracking pattern on the medium. The substrate may have first and second substrate portions. The holographic recording material may be a photopolymer, and the medium may have a sandwiched construction, where the holographic recording material is sandwiched between the first and second substrate portions. The optically detectable tracking pattern may be replicated on at least one of the substrate portions. Alternatively, the optically detectable tracking pattern may be recorded as a holographic grating in the holographic recording material. The tracking pattern may facilitate the ability to pinpoint the location of the holographic bit maps on the holographic medium to within a fraction of a micron.

Abstract: A super-resolution recordable optical disk includes a substrate and forms sequentially on the substrate an under dielectric layer, a mask layer, an interface layer, an organic dye layer, an isolation layer, and a protection layer. A laser beam is projected into the organic dye layer through the substrate to record signals. And a super-resolution recordable optical disk for high numerical apertures also is provided that includes a substrate and forms sequentially on the substrate an organic dye layer, an interface layer, a mask layer an under dielectric layer, and a thin polycarbonate layer. A laser beam is projected into the organic dye layer through the thin polycarbonate layer to record signals.

Abstract: An optical data storage system writes or reads information with respect to an optical storage medium using an optical pickup including a solid immersion optical system or a solid immersion lens for generating a near-field and emitting a light beam. The optical storage medium includes a recording layer which is formed on a surface of an optical transmissive layer opposite to another surface of the optical transmissive layer which opposes the solid immersion optical system or solid immersion lens. The thickness of the optical transmissive layer is larger than one wavelength of the light beam. The interval between the surfaces of the solid immersion lens or solid immersion optical system and the optical transmissive layer is smaller than one wavelength of the light beam. Thus, the light beam reflected from the inside of an air gap and the inside of the optical storage medium between the air gap and the recording layer does not function as noise with respect to the light reflected from the recording layer.

Abstract: A near-field optical recording medium comprises a recording layer capable of writing, reading and erasing information using an evanescent light, the evanescent light having a beam spot size smaller than the wavelength of a source light, wherein the recording layer is a stable amorphous layer mainly comprising a photochromic compound having a glass transition point of 55° C. or higher and a molecular weight of 3000 or less.

Abstract: In a method of recording and reproduction using a magnetic storage medium, a magnetic storage medium (5) is used in which at least magnetic recording film (2) and a superconducting film (3) are deposited. According to the method, the superconducting layer (3) is partly heated where data is either recorded in recording or reproduced in reproduction, using a semiconductor laser (6) to or beyond its critical temperature at which diamagnetism disappears. Thus, in recording, data can be recorded with high density without affecting adjacent parts of the magnetic recording layer regardless of the physical size of the magnetic head. In reproduction, data can be reproduced from a minuscule part at high S/N ratios with crosstalk from adjacent bits being substantially eliminated.

Abstract: An element for reflecting, transmitting, focusing, defocusing or wavefront correction of electromagnetic radiation in the terahertz frequency range. The elements include a grid of conductive strips including active regions comprising a chalcogenide phase change material. The chalcogenide material can be in an amorphous, crystalline or partially crystalline state. The dispersive characteristics of the grid (e.g. impedance, admittance, capacitance, inductance) influence one or more of the reflection, transmission, state of focusing or wavefront characteristics of incident electromagnetic radiation through the action of a stored phase taper formed by establishing a crystallinity gradient over a series of active chalcogenide regions or domains in one or more directions of the element.

Abstract: An optical recording medium in which deposition of impurities or damage to a surface of the medium illuminated by the light for signal recording and/or reproduction is to be prevented from occurring. An amine salt compound of perfluoropolyether having terminal carboxylic groups, represented by the chemical formulas (1) and/or (2): Rf—COO?N+HR1R2R3??(formula 1) R1R2R3N+H?CO—Rf—COO?N+HR1R2R3??(formula 2) where Rf denotes a perfluoropolyether group and R1, R2 and R3 denote hydrogen or a hydrocarbon group, is held on the surface side illuminated by light.

Abstract: An optical magnetic recording medium in which reproduction is implemented by transcribing a mark to a reproducing layer based on a magnetic field from a recording layer, includes a reproducing layer, a non-magnetic layer, and a recording layer including a first recording layer and a second recording layer, wherein the reproducing layer, the non-magnetic layer, and the recording layer including the first recording layer and the a second recording layer are stacked in this sequence; the regenerating layer has a property of an easy magnetization in an in-plane direction at room temperature; the first recording layer and the second recording layer each has a property of easy magnetization in a vertical direction to the in-plane direction at room temperature in a single layer; and there is a relation of M2<M1 wherein a composition of a rare-earth metal comprising the first recording layer is defined as M1 (at %) and a composition of a rare-earth metal comprising the second recording layer is defined as M2 (at %

Abstract: The invention provides an optical recording medium having excellent weatherability and a process for producing the same. The optical recording medium is provided with an organic dye layer, a reflecting layer and a protective layer in this order on a light-transmittable substrate. The organic dye layer contains an organic solvent in an amount of 2% to 15% by weight based on the organic dye. A solution, prepared by dissolving an organic dye in an organic solvent, is applied onto the light-transmittable substrate by a spin coating method to form an organic dye layer. A reflecting layer is formed on the organic dye layer without performing a drying treatment of the organic solvent in the organic dye layer, followed by forming the protective layer on the reflecting layer. The result is an optical recording medium containing an organic solvent in an organic dye layer in an amount of 2% to 15% by weight based on an organic dye.

Abstract: A stamper reception layer 11 of an optical disk producing sheet 1 is composed of a polymeric material that has energy-curing properties and possesses a pre-curing storage elastic modulus of 103 to 106 Pa. The number of deposits on a stamper can thus be reduced with this optical disk producing sheet 1.

Abstract: The present invention provides a recording medium having a plurality of charge accumulating regions each containing a first material capable of accumulating an electric charge and a photoconductive region containing a second material whose conductivity is increased by light absorption, a recording apparatus including such a recording medium, and a method recording information on such a recording medium. In the present invention, information is recorded on the recording medium by irradiating the photoconductive region with light and by injecting an electric charge into the charge accumulating region via that portion of the photoconductive region which is irradiated with light.

Abstract: An optical recording medium includes a) a dielectric layer, b) a recording layer, and c) a reflective layer, which are stacked on a surface of a substrate in the described order or stacked on the surface in the order of b) the recording layer, a) the dielectric layer, and c) the reflective layer. The recording layer contains a mixed nickel oxides which decomposes to release a gas and becomes transparent upon heating.

Abstract: The present invention relates to an optical medium, having on at least one face (10), a superficial recording level (20) and a buried recording level (30), capable of being read and recorded by means of an optical beam having a wave length between 620 and 670 nanometers, and wherein each of the levels has a reflectivity between 6% and 12%.

Abstract: Optical data medium containing in the information layer, a dye as a light-absorbing compound Abstract optical data medium containing a preferably transparent substrate which is optionally already coated with one or more barrier layers and on the surface of which an information layer which can be recorded on using light, optionally one or more barrier layers, and a cover layer containing a radiation-cured resin, have been applied, which data medium can he recorded on and read using focused blue light through the cover layer on the information layer, preferably laser light with the wavelength between 360 nm and 460 nm, the information layer containing a light-absorbing characterized in that at least one dye is used as the light-absorbing compound wherein the cover layer dies have a total thickness of 10 &mgr;m 177 m and the numerical aperture NA of the focusing objective lens setup is greater or equal 0.8.

Abstract: Disclosed are magneto-optical recording media comprising at least a reflection layer, a recording layer and a dielectric layer laminated on a substrate in this order, wherein the thickness of the dielectric layer is not less than 140 nm or wherein the dielectric layer is provided by the lamination of upper dielectric layer and lower dielectric layer in which the thermal conductivity of the upper dielectric layer is higher than that of the lower dielectric layer. By arranging the thickness of the dielectric layer in a specific range, the surface roughness of a media in not more than 1.5 nm, and providing a reflection layer composed of a noble metal alloy, achieved is a magneto-optical recording medium able to record constantly in near-field magneto-optical recording, suitable for narrow track pitch, and having excellent SNR, resolution, and recording sensitivity.

Abstract: A photo-curable transfer sheet having a photo-curable layer comprising a photo-curable composition, the photo-curable composition being deformable by application of pressure and containing a reactive polymer having a photopolymerizable functional group. The photo-curable transfer sheet preferably has a light transmittance of not less than 70% in a wavelength rang of 380 to 420 nm. An optical information recording substrate and medium prepared by the sheet. The sheet easily and precisely enables transfer of unevenness of the surface of a stamper by pressing.

Abstract: A method of manufacturing an optical recording substrate, comprising the steps of:

Abstract: A magnetic recording medium for thermally-assisted recording is a bilayer of a high-coercivity, high-anisotropy ferromagnetic material like FePt and a switching material like FeRh or Fe(RhM) (where M is Ir, Pt, Ru, Re or Os) that exhibits a switch from antiferromagnetic to ferromagnetic at a transition temperature less than the Curie temperature of the high-coercivity material. The high-coercivity recording layer and the switching layer are exchange coupled ferromagnetically when the switching layer is in its ferromagnetic state. To write data the bilayer medium is heated above the transition temperature of the switching layer. When the switching layer becomes ferromagnetic, the total magnetization of the bilayer is increased, and consequently the switching field required to reverse a magnetized bit is decreased without lowering the anisotropy of the recording layer. The magnetic bit pattern is recorded in both the recording layer and the switching layer.

Abstract: An optical information recording medium is here disclosed which comprises a transparent substrate, a recording layer comprising an organic dyestuff on which information can be written by a laser beam, a reflective layer and a protective layer formed in this order on the substrate, the aforesaid optical information recording medium being characterized by containing a pit-edge control agent for the formation of recording pits, particularly a dyestuff thermal decomposition accelerator in the recording layer. By the addition of the pit-edge control agent, deviation properties and jitter properties can be remarkably improved, whereby a CD-R medium having a low error rate and good recording properties can be provided. In consequence, stable compatibility with a commercial CD player can be secured.