Pseudo-reflective read inhibitor for optical storage media

ES 2 287 007 T3 description

Pseudo-reflector read inhibitor for optical storage media.

1. Field of the invention

The present invention relates generally to the field of optical media. More particularly, the present invention relates to time-sensitive disposable optical media.

2. Discussion of Related Art

Optical discs such as CDs and DVDs are sold and rented to consumers for home use. The content of such optical discs may consist of music, movies, software, or data. Unfortunately, buying CDs and DVDs can be expensive. The price is not primarily related to the manufacturing prices of the optical discs, but to the value of the information, such as movies or software, that is encoded on the discs. Providers of such content, such as movie studios or software companies, do not want to sell low-priced copies of their material that have a long life on the market. CD and DVD rental allows consumers to access information at a low price, but the obligation to return rented discs on time is inconvenient. It would be desirable to have optical media (for example, a disc ) that the user could buy at a low price, that would solve the content providers' concern about the duration of their content on the market and that did not present the disadvantage of having to be paid back, as is the case with video movie rentals today. Also, it would be desirable to manufacture such optical discs at a low cost and with minimal changes relative to current optical disc manufacturing processes.

So far, it has not been possible to fully satisfy the requirements of a low price, a limited duration of the contents, avoiding returning the rented product and some minimal changes in relation to the manufacturing procedures mentioned above. What is needed is a solution that meets all these requirements. The present invention aims to satisfy these requirements, among others.

Summary of the invention

An objective of the present invention is to simultaneously satisfy the aforementioned requirements of a low price, a limited duration of the contents, avoid returning the rented product and minimal changes in relation to manufacturing procedures that, in the case of the prior techniques, do not were satisfied simultaneously.

An embodiment of the present invention is based on an optical disc, comprising: a substrate; a metallic layer coupled to said substrate; and lacquer adhered to said metallic layer, wherein the optical properties of said substrate change with exposure of said substrate to air, and said exposure degrades the readability of data recorded on said optical disk. Another embodiment of the present invention is based on a package comprising an optical disc, and said optical disc comprises: a substrate; a metallic layer coupled to said substrate; and lacquer adhered to said metallic layer, in which when opening said package a process is put into operation that changes the optical properties of said substrate and thus degrades its ability to read the data recorded on said optical disk.

Another embodiment of the present invention is based on an optical disc, comprising: a substrate; a metallic layer coupled to said substrate; and lacquer adhered to said metallic layer, in the at least one element selected from the group constituted by said substrate and said lacquer allows controlled exposure of said metallic layer to air, and in this way the readability of the recorded data is degraded in said optic disc. Another embodiment of the present invention is based on a package comprising an optical disc, and said optical disc comprises: a substrate; a metallic layer coupled to said substrate; and lacquer adhered to said metallic layer, in which when opening said package a process is put into operation that changes the reflective properties of said metallic layer, and in this way its ability to read the data recorded on said optical disk is degraded.

These and other objects and embodiments of the present invention will become more apparent when considered in conjunction with the following description and accompanying drawings. It should be understood, however, that the following description, in indicating the preferred embodiments of the present invention and numerous specific details thereof, is provided by way of illustration and not limitation.

US Patent No. 5,815,484 discloses optical storage media for use in optical scanners adapted to limit access to information thereon. WO 98/11539 discloses a machine-readable optical disc featuring a read-inhibiting agent that is activated by removing an insulating layer or by initial reading of the disc.

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Brief description of the drawings

A clear concept of the advantages and of the elements that constitute the present invention, and of the components and the operation of the modeling systems that are provided with the present invention, will become more clearly apparent with reference to the embodiments of example, and therefore not restrictive, which are illustrated in the attached drawings and which form part of the present description, where the same reference characters (if found in more than one image) indicate the same parts. It should be noted that the elements illustrated in the drawings are not necessarily represented to scale.

Figures 1a to 1b illustrate a schematic side views of an optical disc, and represent an embodiment of the present invention.

Figures 2a to 2b illustrate a schematic side views of another optical disk, and depict another embodiment of the present invention.

Description of preferred embodiments

The present invention and the various advantageous elements and details thereof are explained in more detail with reference to the non-limiting embodiments which are illustrated in the accompanying drawings and detailed in the following description of the preferred embodiments. Descriptions of well-known components and process techniques are omitted so as not to unnecessarily confuse the present invention in detail.

The context of the present invention comprises reading data from optical media. Optical discs represent a generic class of optical media. The subgeneric class of DVD-ROMs can comprise any type of digital information. DVD-Video is based on the DVD-ROM standard as well as the standards represented by MPEG-2 and Dolby Digital. The present invention may utilize data processing procedures that transform the signals produced from the data encoded on the optical media so that they drive discrete interconnected hardware elements; for example, to start, stop and / or actuate other functions of the media reader (device) that accesses the data on the optical media.

The concept of the present invention encompasses disposable optical media, such as, for example, a time-sensitive disposable digital video disk (DDVD). A DVD can be manufactured or packaged in such a way that it can be used only for a limited period of time or a limited number of uses.

DVD can react with oxygen in the air so that once it has been removed from the airtight packaging, the surface will hide some of the underlying data. For example, some plastics may darken or blacken.

DVD can react with other components of the air such as humidity or other gases so that once it has been removed from the air-tight packaging, the surface will hide some of the underlying data. Again, some plastics may darken or blacken.

DVD can react with light, such as laser light used to read data, so that it cannot be read again after a certain number of readings. It can be a photochemical procedure similar to photography or the darkening of a substance when exposed to light.

DVD can react to ambient light so that it cannot be read again after a certain number of readings. Again, it can be a photochemical procedure similar to photography or the darkening of a substance when exposed to light.

An electrostatic or mechanical reaction may occur when the DVD is removed from the packaging and timed data destruction is activated. Power can be supplied for this by a small battery or simply by the energy released when the DVD is removed from its packaging.

The procedure of removing the DVD from its packaging or playing it on a device may somehow trigger the timer. For example, removing a DVD from its packaging can break a seal by exposing both the data side and the labeled side of a single-sided DVD to reagents included in both the DVD and the packaging materials, and in this way, the procedure that renders the DVD unusable after a certain period of time or a certain number of uses is activated.

The DVD player can actively read certain encoded identification information from the DVD and prevent it from being played again. This can be done both by actively modifying the DVD and by storing such information on the player or on a network.

Degradation can occur relatively quickly (S-form), if possible, minimally affecting data for a certain initial period, followed by rapid loss of data. By understanding the DVD a finite and controlled amount of antioxidant together with a substance that reacts3

EN 2 287 007 T3 ne with oxygen it is possible to initially protect the data and then, when the antioxidant is depleted, rapidly degrade the DVD.

The present invention can be readily applied to related media such as compact discs (CDs), laser discs, CD-ROMs, tapes, and so on. Applications of the present invention include storing movies with a limited number of views, which could replace the video rental market. Other applications of the present invention include "test" discs with music, software or other types of digital information, music, video, data, game catalogs, etc., which can be ordered by email; Hybrid discs with certain permanent components (for example, upcoming products), games with a limited time to finish them, and so on.

The length of time that the data can be used can range from less than a few seconds to more than several weeks. The length of time that the data can be used can be limited to a single replay or game, a finite number of uses, or even a random number of uses.

No extra layer is required on the disc to achieve the intended results. In one embodiment, exposure to the environment impairs the performance of the metallic layer.

The term "substrate" is defined herein as one or more layers through which the laser light passes before striking the metallic layer. The substrate can be polycarbonate, but other materials known to those skilled in the art can be used.

The term "lacquer" is defined herein as the layer or layers on the back of the disc. One or more of said layers may comprise a material identical or similar to one of those used in the substrate. The laser light is not intended to pass through the lacquer. Typically a single-sided disc (such as a CD or DVD-5) has a reflective metallic layer between the substrate and the layer. In a double-sided disc (such as a DVD10), the layer will usually comprise a layer that joins the two sides of the disc to each other.

In one embodiment, the present invention comprises an optical disc in which the metallic layer comprising the data is not completely protected from the environment. For example, a part of the surface can be deliberately left uncoated with the lacquer or substrate. This allows the environment to act on the unprotected part of the metal layer. The reflective metal can react with a component of the air. For example, a layer of aluminum can oxidize with oxygen in the air to produce aluminum oxide. After a period of exposure to the environment, the quality of the signal reflected by the metal layer will degrade, resulting in poor data quality or even the inability to read the data on the disc.

The rate of degradation can be defined by the metal. It speeds up when the metal is magnesium or silver and slows down when the metal is aluminum. If the metal comes into contact with a second metal, the degradation is accelerated. For example, when aluminum comes into contact with silver, gold or copper, degradation is accelerated. In general, contacting the magnesium or aluminum with a more precious metal accelerates the degradation of the magnesium or aluminum layer. When using two metals, the rate of degradation can be adjusted by the ratio of their exposed areas. When the two dissimilar metals comprise two overlapping films, the rate of degradation is also determined by overlapping.

It is not necessary to leave the entire surface unprotected. For example, it is sufficient to leave unprotected only the key parts of the optical disc that comprise the data necessary to read the rest of the disc.

It is possible to control the period of time required to degrade the metallic layer of the optical disk by controlling the thickness, the quality or the composition of the substrate or of the lacquer. For example, a substrate or a lacquer can be chosen so that the flow of oxygen, nitrogen, water or hydrogen sulfide that reaches the metal surface is a function of the thickness of the layer. Alternatively, the materials comprising the substrate or the layer can be chosen such that layers of equal thickness have different permeabilities to oxygen, water, or hydrogen sulfide. In this way, optical discs can be designed that do not work after a certain period after being exposed to the destructive medium, for example, one hour, six hours, 24 hours, 48 ​​hours, 72 hours or a week.

Alternative embodiment

Another composition that performs a similar function is one in which the substrate itself changes over time. Modifying the substrate can cause its optical properties to change, thereby degrading the signal reaching the reader. Said optical properties can include its refractive index or its transparency.

Furthermore, modification of the substrate can cause the underlying metallic layer to change its optical properties, as described above. In this way, a substrate and / or lacquer can be combined with a reflective layer that becomes non-reflective.

ES 2 287 007 T3

You can change the transparency of a polymeric film as follows: by reacting the film with water; by reacting the film with oxygen; or by crystallization of the polymer, which means a greater alignment of the polymer molecules in the film.

By way of example, a substrate can be selected to change with air components such as oxygen or water. For example, oxygen can oxidize the substrate, causing it to change its transparency or refractive index. Alternatively, the substrate can be designed to absorb water from the air, causing it to swell and change its optical properties. Another example is that the substrate can change its oxygen permeability over time, thus allowing oxidation of the metallic layer. In the latter case, the overall sensitivity of optical media over time can be found as a function of the properties of both the substrate and / or the lacquer and the reflective layer.

The substrate or metallic layer can also be made sensitive to specific wavelengths of light. Exposure to these wavelengths can cause a change in the optical properties of the layer, thereby degrading the signal reaching the reader. Examples include photodepolymerization of the substrate; the photogeneration of acids; singlet oxygen photogeneration; denaturation of polymers (eg, breaking hydrogen bonds). Incorporating light-activated catalysts into the substrate or metal layer can aid in such a process.

Preferably, the quality of the data on the disk remains high for the intended period of time and then declines rapidly. One procedure to achieve this is to print a layer of metallic silver on the back of the disc, above the lacquer. When silver is exposed to air, it acts as a cathode and reduces O₂; aluminum acts as an anode. Corrosion occurs rapidly only if a short circuit occurs between the silver and aluminum layers. The short circuit occurs thanks to the arborescent crystallization of silver through the lacquer.

It is intended to use a lacquer that has a certain ionic conductivity so that the arborescent crystallization of silver occurs through the lacquer. Usually the lacquer comprises polyacrylate. If the polyacrylate is slightly hydrolyzed or if it is, for example, a 2-hydroxyethylacrylate copolymer, there will be some ionic conductivity. Poly (acrylonitrile) or poly (4-vinylpyridine) or poly (1-vinylimidazole) copolymers are preferred. All of them must be conductors of silver, copper or thallium ions (Ag +, Cu 'or Tl +). Thallium is less preferred due to its toxicity.

The chemical equations are as follows:

Silver oxidizes in air:

Ag + + O₂ 2 Ag₂O (forming a complex with the lacquer)

Ag₂O + H₂O + ligand 2 Ag + (forming a complex) + 2 OH^-

The Ag ion⁺ is reduced by aluminum, which is oxidized (if the Ag ion⁺ can be displaced through the lacquer, which is done in such a way as to allow conduction of the Ag ion⁺).

To the³+ + 3 OH Al (OH)₃ Al (O) OH + H₂ O 3 Ag + + Al Al³+ + 3 Ag⁰

The arborescent crystallization of silver starts from aluminum to silver. When the short circuit occurs between the two layers, the "switch" between the anode (Al) and the cathode (Ag) of the battery closes. Corrosion occurs quickly and is disastrous. One skilled in the art will recognize that the Al and Ag in the present example can be replaced with other similar metals.

Given a suitable substrate, the aluminum and silver coatings can be deposited by sputtering. Lacquer can be coated by spinning.

Another aspect of the present invention is a composition that comprises a degradable optical disk as described in the present section packed in a box and an atmosphere that protects it from the environmental stimulus that causes its deterioration. For example, the optical disk described above can be packaged in a metallized aluminum foil wrapper comprising a gas such as carbon dioxide, nitrogen, or argon. The pressure of the gas or gases in the box can be subatmospheric, preferably less than 1 torr. Inert gases such as argon are preferred. This makes it possible to protect the optic disk from oxygen, water and / or light of certain wavelengths.

Another aspect of the present invention is a method of manufacturing the degradable optical disk described above. The method involves coating the substrate or lacquer described above on the metallic layer so that the disk is partially or totally covered, so that the optical signal originating from the disk degrades when exposed to a preselected environmental stimulus.

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Another aspect of the present invention is a process for manufacturing the degradable optical disc by means of a process that changes the optical properties of the substrate and / or the reflective properties of the metallic layer in such a way that they can be partially or completely reversed, and a Total or partially reversible loss of the ability to read data from the optical disc.

The disc can then be exposed to a "reversal medium" that partially or completely reverses the impact of the previous stage. The disc is subsequently packaged in a "protective medium" (which can be identical to or different from the inversion medium). Opening the package causes the loss of the “protective medium” and / or exposure to environmental conditions of oxygen, humidity and / or light, which will cause a new degradation or the loss of the ability to read data from the disk in a certain period of time. It is preferred that said latter disk degradation is difficult or impractical to reverse. For example, certain salts can be mixed with the polycarbonate pellets used in injection molding the substrate. During the injection molding process, these salts can interact with oxygen, carbon dioxide and / or water to form opaque compounds that modify the optical properties of the substrate. Following the steps of the traditional manufacturing process, the optical discs can be chemically reduced in a hydrogen atmosphere, making the polycarbonate substrate clear for laser reading again. The discs can then be packed in a hydrogen atmosphere. Opening the package will result in loss of reducing hydrogen and exposure to atmospheric oxygen, moisture, and carbon dioxide, rendering the polycarbonate substrate opaque after a controlled period of time.

Another aspect of the present invention is a mechanical device that triggers timed destruction of data when the optical disk is removed from the package. In one embodiment, removing the disc from the package can break a seal and expose both the data side and the label side of a single-sided disc to the reagents contained in the disc itself or in the materials. wrapping, thus starting the procedure that renders the disc unusable after a certain period of time or a certain number of views. For example, a reducing gas can be stored in a separate package compartment from the disk. The disc comprises a protective layer that prevents oxidation of the underlying substrate or metal. The package is designed so that, when the package is first opened, a seal is broken and the reducing gas comes into contact with a surface of the disk, thereby causing the destruction of the protective layer. The substrate or metallic layer that was protected from oxidation by the protective layer will then be susceptible to oxidation with air, as described above.

Alternatively, timed data destruction can be initiated by the electrical current or charge provided by a small battery, or simply the energy released when the disk is removed from its packaging. For example, a reversible chromophore can be used. The chromophore is reduced to a colorless state when the electrical potential is applied. When the electrical potential is no longer applied, the chromophore is gradually regenerated by oxidation with oxygen in the air. In its regenerated state, the chromophore absorbs light.

Alternatively, a charge storage device such as a small battery installed in the pack can provide an electric field that inhibits the reaction and destruction of the data read ability of the disk. The procedure of removing the optical disc from its packaging will then interrupt the inhibitory field and initiate the procedure that destroys the disc's ability to read data. For example, the battery applies an electrical potential to the metallic layer that keeps the metallic layer in a reduced state. When the electrical potential is no longer applied, the metallic layer begins to oxidize when it comes into contact with an oxidant such as oxygen in the air.

Another aspect of the present invention is a process for manufacturing a degradable optical disk and packaging it in a box and / or an atmosphere that protects it from the environmental stimulus that causes its deterioration. The present invention further comprises controlling the exposure of the finished optic disc to environmental stimuli that cause its deterioration during manufacturing and / or packaging procedures. For example, optical discs manufactured today can remain unpackaged for a substantial period of time before being packaged. Such a time interval can act to significantly degrade the signal quality of the optical discs of the present invention before the discs are packaged. Therefore, the optical disc should be packaged in the box and / or protective atmosphere within 24 hours after production, preferably within 8 hours after production, more preferably within one hour after production, and even more preferably before 30 minutes after production. In other words, the optical disk must be packaged in its box and / or protective atmosphere in a period of time less than 20% and preferably less than 10% of the expected degradation time period.

It is also possible to manufacture and / or store the unpackaged optical disc in an environment that does not cause its degradation. Such an environment can be, for example, a nitrogen atmosphere, substantially zero air, or controlled lighting. Such a system may be less advisable than quickly packing the disc in a protective box and / or atmosphere due to the high costs associated with such special environments.

Another aspect of the present invention is a method for using the optical disc described above, which comprises packaging the disc in a box and / or atmosphere that protects it from the environmental stimulus that causes its deterioration, then opening the package and exposing the disc to the environmental stimulus that causes its deterioration.

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The level of degradation is intended to be minimal for a certain initial period and then accelerated causing rapid degradation of the data read ability of the optical disc. One process to achieve this is tree crystallization, as described above. Another method to achieve this comprises a controlled and finite amount of antioxidant together with a substance that reacts with oxygen. The antioxidant will protect the data from oxidation reactions until the instant the antioxidant is consumed, at which point the disc will rapidly degrade. For example, an organometallic compound that reacts with oxygen can be packaged with the disc to protect the disc from oxidation while in the package. Alternatively, the organometallic compound can be incorporated into the substrate, and thus continue to protect the metallic layer for a period of time after opening of the wrapper.

The term coupled is used herein as connected, although not necessarily directly or mechanically. The term "substantially" is defined herein as about (eg, preferably 10% of, more preferably 1% of, even more preferably 0.1% of).

The particular material used for the substrates can be any substantially transparent material. Polymeric materials are preferred, such as, for example, polycarbonate, polymethylmethacrylate (PMMA) acrylic or polyolefin. In the manufacturing process it is advantageous to use a polycarbonate material.

However, the particular material selected for the substrate is not essential to the present invention as long as it performs the described function. Typically, those utilizing the present invention will select the best commercially available material based on economics of cost and availability, the expected application requirements of the final product, and the demands of the overall manufacturing process.

Although not limited by any particular performance indicator or diagnostic identifier, preferred embodiments of the present invention can be identified one at a time by analyzing the deterioration of optical properties over time in one way. accurate and precise. More specifically, both the onset and the duration of the deterioration must be predictable. Sudden deterioration (a short duration of deterioration), for example about an hour, is preferred. For example, preferred embodiments of the present invention can be identified, one at a time, by analyzing the presence of a narrow normal distribution of the period from activation (eg, exposure to air) to 50% deterioration. optical (for example, 50% loss of transmissivity or 50% loss of reflectance). Many other optical tests (eg material properties) are possible.

Examples

Specific embodiments of the present invention will be further described by the following non-limiting examples which will serve to illustrate various significant elements in some detail. The examples are intended simply to facilitate an understanding of the ways in which the present invention may be practiced and further enable those skilled in the art to practice the present invention. Therefore, the examples are not to be construed as limiting the scope of the present invention.

Example 1

Referring to Figures 1a through 1b, a side views of an optic disk 100 with a pseudo-transmissive read inhibitor are illustrated. Optical disk 100 comprises a substrate 110, a reflective layer 120, and a lacquer layer 130. Figure 1a illustrates the optical disk 100 in a first state in which substantially the substrate 110 is optically transmissive. Figure 1b illustrates the optical disk 100 in a second state in which the substrate is substantially optically non-transmissive. The transformation from the first state to the second state is, at least in part, a function of the period of time elapsed since the initiating event, in the present particular example, the opening of a substantially gas-impermeable membrane (not illustrated ) that houses the optical disk 100 when it is packaged, distributed, and sold.

Example 2

Referring to Figures 2a through 2b, side views of an optical disk 200 with a pseudo-reflective read inhibitor are illustrated. The optical disk 200 comprises a substrate 210, an encoded data component 220, and a lacquer layer 230. In the present example, the encoded data component 220 is a thin film of metal. Figure 1a illustrates the optical disk 200 in a first state in which substantially the encoded data component 220 is optically reflective. Figure 1b illustrates the optical disk 200 in a second state in which substantially the encoded data component 220 is optically non-reflective. As in the first example, the transformation from the first state to the second state is, at least in part, a function of the period of time elapsed since the initiating event, in this second example, the opening of a hermetic laminar polymeric container ( not illustrated) that contains the optical disc 200 when packaged, distributed, and sold. Practical applications of the present invention

A practical application of the present invention that presents a technological value are optical supports sensitive to the passage of time. Furthermore, the present invention is useful in conjunction with DVD-ROMs (such as those

ES 2 287 007 T3 are used to store software), or together with DVD-Audio (such as those used to store music), or together with DVD-video (such as those used to store movies), or similar. There are practically innumerable uses of the present invention, which will not be detailed here.

Advantages of the present invention

Optical carriers with time-sensitive properties, which represent an embodiment of the present invention, can be economically efficient and advantageous for at least the following reasons. The present invention makes it possible to produce a low-cost sales product. The present invention provides a product having a limited potential shelf life. The present invention makes it possible to avoid having to return rented products. The present invention involves minimal changes to current manufacturing procedures.

All of the embodiments of the present invention that have been described herein can be made and practiced without undue experimentation. Although the best mode of carrying out the present invention contemplated by the inventors has been described above, the practice of the present invention is not limited thereto. Therefore, those skilled in the art will appreciate that the present invention may be practiced in ways other than those specifically described herein.

For example, individual components should not be in the described shapes or assembled in the described configuration, but can be provided in virtually any shape and assembled in virtually any configuration. Furthermore, it is not necessary to make the individual components with the materials described, but can be made from practically any suitable material. Furthermore, although the optical media described herein may be a physically separate module, it is clear that the optical media can be integrated into the apparatus with which it is associated.