KR20060052900A - Content information layer for an optical record carrier - Google Patents

Abstract

An optical record carrier (2) and associated methods and devices are described. The carrier (2) comprises at least one user information layer (4a,4b) arranged to be scanned by first radiation, and at least one content information layer (3a,3b) or label layer. The content information layer comprises representing content information and having a first transmission for said first radiation and a second, lower transmission for a different, second radiation.

Description

CONTENT INFORMATION LAYER FOR AN OPTICAL RECORD CARRIER}

The present invention relates to a content information layer for an optical recording medium, a method of manufacturing a recording medium comprising such information layer, and an apparatus for embedding content information in the information layer. The content information layer is particularly suitable for applications on non-limiting double sided optical discs.

An optical disc is an information storage disc that can be read by scanning the disc with a beam of radiation of a predetermined wavelength. The term radiation refers to radiation of the full wavelength of electromagnetic radiation, as well as radiation belonging to the visible portion of the spectrum.

Conventional optical discs exist in a variety of formats including CDs (compact discs), DVDs (digital multifunction discs) and BDs (Blu-ray discs). 1 shows an example of a conventional optical disc 100. The disk is formed of a plurality of layers 103, 104, 105, 107. The user information layer 104 stores information on the disc 100 and is read by the radiation beam incident on the entrance face 106. In a state where the substrate layer 105 provides a mechanical support or protects the user information layer 104 from environmental influences, the user information layer is generally covered by the cover layer 103. In order for the user to identify the disc from other similar discs, a content information layer 107 called a label is provided on the surface of the disc opposite the entrance face 106. The content information or label information is visible to the naked eye, that is, the user can read and interpret the naked eye. The content information is displayed or encoded in an area that reflects or absorbs ambient light incident in a different way than the medium surrounding the environment. The region may consist of a dye having a different color from the surrounding medium. A single region may form one pattern, or multiple regions may form one or more patterns, such as letters and images. The content information generally provides information about the content of the user information layer and the disc type. It contains relevant information for a range of users, such as the type of recording medium (for example, CD, DVD, CD-R, CD-RW), the name and track list of the music disc, or the description of the software for the computer program distribution disc. It may include.

In order to increase the storage capacity of the optical disc, it is desirable to store user information using both sides of the disc, i.e. obtain a double-sided disc. However, since the reflective / absorbing layer interferes with the scanning of the user information layer on the side of the disc, it is impossible to provide a standard user visible content information layer or label on the disc. If no content information layer is provided, identification of the disc becomes a problem.

It is an object of this embodiment to provide an improved content information layer that addresses one or more of the problems of the prior art mentioned herein and others.

It is an object of certain embodiments of the present invention to provide a content information layer that can be applied to both side optical recording media and does not interfere with the scanning of information on both sides of the recording medium.

According to a first embodiment, the present invention comprises at least one content information layer and at least one user information layer arranged to be scanned by a first radiation through the content information layer, the content information layer comprising a peripheral medium. And at least one area representing content information, wherein the content layer transmits first radiation, and the area and the peripheral medium provide an optically visible contrast for different second radiation. .

The content information layer, the at least one area, and the surrounding media must transmit first radiation used to scan the user information layer of the recording medium. The transmittance for the first radiation is preferably very high so that writing, reading and / or erasing of the user information layer is not affected by the presence of the content information layer.

The single pass transmittance of the content information layer for the first radiation is at least 70%, preferably at least 90%, for the recording medium on which the user can record user information. The transmittance of the region and the surrounding material for the first radiation is preferably about the same, i.e. around 10%, more preferably around 3%.

The region and its surrounding medium exhibit an optical contrast at a second radiation different from the first radiation. The second radiation is used to observe the content information. The contrast is preferably sufficient for the naked eye to read the content information. For improved visibility, a contrast of at least 30% is desirable. Contrast relates to the second radiation. In the case where the second radiation has a small or large wavelength range, the contrast relates to the small or large range, respectively. For example, a high reflection of an area as compared to the surroundings in the red portion of the spectrum should have minimal contrast in the red portion so that the region appears red to the viewer.

The contrast between the region and the surrounding medium may be in the form of different kinds of reflections, for example different colors, specular reflections and diffuse reflections, or different amounts of reflection of radiation. The second radiation belongs to one or more components of the ambient light, preferably the visible portion of the spectrum. The predetermined contrast must be obtained for at least one component of the second radiation in the visible spectrum.

By providing such a content information layer, at least one area allows for uninterrupted transmission of the first radiation used to scan the user information layer. However, in the case of irradiation with a second radiation such as ambient light, the area can be visually observed by the user because it reflects or absorbs at least a portion of the incident radiation. Therefore, the content information layer in which the content information is recorded in this area does not interfere with the scanning of the user information in the user information layer. Thus, such a content information layer may be embossed inside or on a double-sided optical recording medium to provide content information about the recording medium.

In a preferred embodiment, the at least one region has a low second transmission for second radiation that is different from the first transmission for first radiation. Low transmission for the second radiation can be caused by more absorption or reflection of the area. The second transmittance is preferably much lower than the first transmittance such that the region absorbs or reflects a substantial amount of incident radiation so that the contrast is visually determined under ambient light conditions.

In a preferred embodiment, the content information layer has a high transmittance for the first radiation with a given polarization and provides optical contrast for the second radiation with different polarizations. The first radiation can be linearly polarized, for example, and the second radiation is linearly polarized in a direction orthogonal to the polarization direction of the first radiation. The second radiation may be one or more components of ambient light having the aforementioned linearly polarized light. The area in the content information layer may be made of a material having a dependency-dependent transmittance, preferably a birefringent material. The medium surrounding the region is non-birefringent. When the birefringent material is properly oriented, the incident first radiation passes through the region and the surrounding medium and does not experience a change in refractive index. In contrast, the second radiation undergoes a change in refractive index as it passes through the region, reflecting a portion of the incident second radiation. The second radiation passes through the surrounding medium and does not experience a change in refractive index. The reflection difference of the second radiation between the area and the surrounding medium causes an optical contrast that makes it possible to read the content information stored in the layer. The transmission of the region and the surrounding medium for the first radiation may be up to 100%. The transmission of the area for the second radiation may be about 95% for the area formed with a single ball refractive volume. The transmittance may be as low as 9% for an area formed of a plurality of birefringent particles dispersed in the matrix material. The particles scatter scatter the second radiation incident by a plurality of reflections and refractions. The matrix material may be isotropic or anisotropic.

In another particular embodiment, the content information layer has a high transmittance for first radiation having a predetermined wavelength and provides optical contrast for second radiation having a different wavelength. The wavelength of the first radiation may be the wavelength of the laser used to scan the recording medium. The second radiation may be one or more components of ambient light having different wavelengths. The area in the content information layer can be made of a material having a wavelength dependent transmittance. The medium surrounding the region is made of a material having a different wavelength depending on the transmittance. Both materials may be dyes. The region can be made only with dyes or with dyes embedded in the matrix. The medium surrounding the region may be made of the same material as the matrix. The transmission of the region and its surrounding medium at the wavelength of the first radiation can be high. The reflectance of the second radiation in the region is different from the reflectance in the surrounding medium, providing a certain optical contrast. The transmittance of the region and the surrounding medium with respect to the wavelength of the first radiation is 90% or more, and may be almost 100%. The reflectance of the region for the second radiation may have a value of 0 to 100%, and the reflectance of the surrounding medium may have a different value in the above range. The contrast caused by the reflectance difference should be obtained for at least one wavelength in the visible portion of the spectrum. The transmission can be between 100% at the wavelength of the first radiation and 0% at another wavelength. For example, if the region has a high reflectivity of about 600 nm and has low emission at other wavelengths and the surrounding medium has low reflection at all wavelengths in the visible portion of the spectrum, the region will appear red in the light background.

The content information layer may comprise the same material for the area and its periphery, but the optical properties of the material in the area have been produced differently than that of the periphery. The optical characteristic can be wavelength dependent or dependency dependent of the transmission rate. For example, the material includes birefringent particles dispersed in an isotropic matrix. In such a way that the radiation with the first blunt tube experiences the same refractive index in the matrix and in the particles in the region and in the surroundings and in the particles with the radiation with the second polarization in the region and in the matrix with the same refractive index in the surrounding particles and in the matrix In a way to experience the refractive index, the birefringent orientation of the particles in the region is chosen differently from the birefringent orientation of the surrounding particles.

In another embodiment, the content information layer includes a plurality of colored sub-regions having a predetermined area, spaced at substantially equal intervals, and substantially opaque. The term color includes black, gray and white. Sub-regions, for example colored ink dots, are deposited on the surface of the substrate of the optical recording medium. Optical recording medium reading or recording devices are typically tested for strength against fingerprint sensitivity by carefully placing ink dots on the substrate surface. Since the light beam, i.e., the first radiation beam, at the surface of the substrate has a substantial width, small ink dots do not interfere with writing information to or reading information from the deep user information layer. Therefore, the colored subregions preferably have a size of 75 to 20000 m 2. The last figure corresponds to a subregion with a diameter of approximately at least 150 μm. It is preferable that the diameter is less than 50 µm. In order to ensure an optically sufficient transmittance to the first radiation, the colored sub-region occupies the content information layer zone at a selected value of 10 to 30% of the total, and is distributed substantially uniformly above the content information layer zone. . When distributed uniformly, sudden transmittance fluctuations are prevented. An important part of the translucent label prevents sudden transmission fluctuations between the boundaries of the visible pattern of the label. With sub-regions that are substantially opaque, this transmittance variation does not actually exist. Visually sharp edges can be obtained by using different ink colors for the subregions while maintaining the same ground coverage. In the case of an optical recording medium reading or recording apparatus, only the unoccupied recording medium surface is important for the signal level. However, dots may appear as sources of light scattering, but because they are out of focus, such scattering does not interfere with the reading or writing process. Slightly transparent sub-regions, for example dots, are excluded, in which case it is desirable to create a soft edge of the visible level information by gradually decreasing the dot size or dot density at the edge.

In another embodiment, the content information layer includes a plurality of sublayers of different color that are substantially equally transparent to the first radiation. For example, a homogeneous dye layer or coating of thin sheets that are transparent at the read or write wavelength is used. The dye zone preferably shows little border between dye-non-dye or dye1-dye2 in the read or write area. This dye zone must not only be substantially transparent, but also must be substantially the same in transparency to the reading or recording wavelength of the first radiation, for example an optical recording medium reading or recording device. It is preferred that homogeneous and optically clear dyes be used and not dyes, ie emulsions, containing small colored particles. Furthermore, in order to minimize the disturbance of the optical wavefront of the focused radiation beam while recording information to or reading information from the user information layer of the optical recording medium at the first radiation wavelength, the content information layer is applied at the first radiation wavelength. It is preferred if it has a substantially uniform optical thickness. This may be achieved if the content information layer comprises a substantially optically transparent and flat cover layer (facing at least away from at least one user information layer). In this manner, the physical thickness variation and gap between the sublayers is filled, and the optical thickness variation is reduced.

In another embodiment, the content information layer includes a dielectric layer having antireflective properties at a first radiation wavelength, wherein the dielectric layer represents visible content information. For example, a dielectric coating similar to wearing sunglasses is used to coat the label side, in whole or in part, depending on the desired label design. Such coatings typically have a total thickness of ¼ wavelength. It is desirable that there are few boundaries between the different colors. There is also a need for good transparency to the write or read wavelength.

The optical recording medium can be combined to combine two or more of the following characteristics. The material of the content information layer may be a birefringent material dispersed in a matrix material, the material may be a dye, the area inside the content information layer may be patterned, the recording medium may be double sided, and at least one side May have a content information layer and each side may have a user information layer.

In another embodiment, the present invention includes at least one content information layer and at least one user information layer arranged to be scanned by a first radiation through the content information layer, wherein the content information layer comprises a periphery. A recordable material in a pattern that provides at least one area representing content information on the medium, wherein the content layer transmits first radiation, and the area and the peripheral medium provide optical contrast for different second radiations. An optical recording medium is provided.

In such a recording medium, the presence and position of at least one area in the content information layer can be changed under external influence such as irradiation or electric field. Such a recording medium makes it possible to record content information in a non-recorded or partially recorded content information layer. In addition, content information can be changed by erasing old content information or recording new content information.

In the case where the material of the region is birefringent, the recording process may include locally changing the orientation of the birefringence, and in the case of the liquid crystal material, changing the orientation of the liquid crystal molecules.

In yet another embodiment, the present invention provides an apparatus for recording content information in a content information layer on an optical recording medium, the optical recording medium comprising at least one content information layer and first radiation through the content information layer. At least one user information layer arranged to be scanned by the content information layer, wherein the content information layer comprises a recordable material, and the apparatus provides at least one area in the pattern direction representing the content information. It is arranged to record material, and the area and the peripheral medium provide a recording apparatus that provides optical contrast for different second radiation.

In another embodiment, the invention provides an optical recording comprising at least one content information layer comprising a recordable material and at least one user information layer arranged to be scanned by first radiation through the content information layer. A method of recording content information on a medium, comprising the steps of: recording material of the content information layer to provide at least one area in a patterned direction representing the content information, wherein the area and the surrounding medium are at different second radiations; There is provided a recording method that provides optical contrast with respect to the present invention.

In yet another embodiment, the present invention provides a method of manufacturing an optical recording medium, comprising: providing at least one user information layer arranged to be scanned by a first radiation, and at least one area representing content information. Providing at least one content information layer comprising a recordable material for providing, wherein said area and said peripheral medium provide an optical contrast for different second radiation.

BRIEF DESCRIPTION OF DRAWINGS To help understand the present invention and to show how embodiments of the present invention are implemented, it will be described with reference to the accompanying drawings.

1 shows a cross-sectional view of a single side optical disk.

2 is a cross-sectional view of a double-sided disc incorporating a content information layer according to the first embodiment of the present invention.

3A-3F illustrate another embodiment of a plan view of a content information layer, illustrating different orientations of two-phase anisotropy forming the content information layer.

4A and 4B show different forms of two phases of a content information layer.

5A and 5B schematically illustrate the side chain liquid crystal polymer (SCLCP) and liquid crystal diacrylate C3M, respectively, used during the manufacturing method according to an embodiment of the present invention.

6 shows an apparatus for scanning an optical recording layer including a content information layer according to an embodiment of the present invention.

7 is a cross-sectional view of a double-sided disc incorporating a content information layer according to another embodiment of the present invention.

8 illustrates a cross-sectional view of a single sided disc incorporating a content information layer in accordance with another embodiment of the present invention.

The inventor has realized that the content information layer or label layer may be provided while overlapping the user information layer on the optical recording layer but does not interfere with the scanning of the user information layer.

 This content information layer (or at least a portion of the content information layer) (herein referred to as an area) is arranged to transmit (ie, substantially reflect or not absorb) the first radiation beam used to scan the user information layer. . This area is visible to the naked eye when arranged to reflect and / or absorb other second radiation. When most radiation sources (including embodiments) irradiate non-polarized radiation, the region may appear opaque under the influence of ambient light because at least the radiation of the second radiation is reflected or absorbed.

The region is preferably arranged to transmit the first radiation and to reflect or absorb all other radiation. This increases the visibility of the area under irradiation with the second radiation.

By arranging the region in any desired shape or structure (e.g., text or image), it is possible to simply provide information indicating the content of the disk or the origin of the disk, information identifying the disk, or a satisfactory pattern. Information can be prepared.

In this manner, the content information layer may be disposed on the double-sided disc without preventing the user information layer of the disc from being scanned by the radiation of the first polarization.

This content information layer may be applied to any optical recording medium including a card and a cylindrical medium, and it should be recognized that it is not limited to the optical disc. In addition, such content information layers may be provided on a single sided medium, for example, to provide information or patterning on both sides of the medium to increase the amount of information available to the user or to enhance the overall appearance of the medium. Can be.

1 shows a first embodiment of a recording medium according to the present invention. The content information layer is provided on the entrance face 106. Alternatively, the content information layer may be covered with a transparent layer, embedded in a substrate, or disposed on the user information layer. The content information in the content information layer is represented by an area comprising a material having a high transmittance with respect to the radiation used to scan the user information layer 104. The material has a low transmission for radiation of different wavelengths. Suitable materials for this region are generally dyes having a strong wavelength dependent transmission. Examples of dyes and their colors under ambient light conditions are as follows.

1.1'-diethyl-2,2'-carbocyanine iodide (permeable for purple, CD and DVD)

2- [6- (diethylamino) -3- (diethylimino) -3H-xanthene-9-yl] benzonic acid (permeable for green, CD, DVD and BD)

2,3,5,6, -1H, 4H-tetrahydro-9- (3-pyridyl) -quinolizino- [9,9a, 1-gh] coumarin (permeable for yellow, CD and DVD)

2- (p-dimethylaminostyryl) -pyridylmethyl iodide (permeable for orange, CD and DVD)

2- (p-dimethylaminostyryl) -benzothiazolyretil iodide (permeable for red, CD, DVD and BD)

From here,

CD is a compact disc (first radiation wavelength of 780 nm),

DVD is a digital multifunction disc (first radiation wavelength of 650nm) and

BD is a Blu-ray Disc (first radiation wavelength of 405 nm).

Since such dyes can be added in very small amounts to the matrix, these dyes do not substantially affect the optical path length. Therefore, aberrations in the optical path due to the optical path length difference caused by the dye can be ignored. In addition, a dye may be selected that brings the refractive index of the matrix close to a large range.

 2 shows an optical disc 2 according to another embodiment of the invention. The content information layer may be a cover layer on the substrate, such as the layer of FIG. 1, a layer at any location within the substrate, or a layer disposed directly on the user information layer. In the embodiment of Figure 2, the content information layer replaces the cover layers of the disk and the substrate. In FIG. 2 the disc 2 is double sided and thus has two separate user information layers 4a and 4b mounted on either side of the separation layer or substrate 5. Each content information layer 3a, 3b overlaps the user information layers 4a, 4b. Each user information layer 4a, 4b is scanned by providing a polarized radiation beam that is incident on each user information layer 4a, 4b through corresponding entrance surfaces 6a, 6b.

Implementing such a content information layer as an area with dependent-dependent transparency can be accomplished in a number of ways.

In general, the content information layer may be composed of a continuous first phase (matrix) and a second phase having continuous, bicontinuous, or preferably distributed characters (in the form of small areas). The zone of the second phase is a zone, and the zone of the first phase surrounds the zone. At least one of the two phases has anisotropic properties and exhibits anisotropy such as liquid crystal LC. The biphasic phase may be formed of a single material (in different states or with different orientations) or may be composed of two or more separate materials. A possible implementation is shown schematically in FIGS. 3A-3F.

3A-3F show a top view of a content information layer 3 according to another embodiment of the invention, which provides an exemplary implementation in the form of polarization dependent scattering regions.

In each case, the information content layer 3 comprises a first phase 43b which provides a matrix for the particles of the second phase 43a. Arrows or cross-shaped circles 43a 'and 43b' in each of the figures indicate anisotropic directions of the respective images.

For example, in FIG. 3A, the matrix material forming the first phase 43b has anisotropy indicated by a cross-shaped circle, i.e. it shows that the anisotropy extends in a direction orthogonal to the plane of the drawing. In contrast, the second phase 43b has double arrows extending from side to side, i.e., anisotropy extends across the drawing. In the diagram where the two arrows intersect (ie 43b 'in FIG. 3E and 43a' in FIG. 3F), this indicates that the relevant phases are isotropic.

Isotropic materials are materials that have the property that the orientation does not change (refractive index in this particular description). Anisotropic materials are materials whose physical properties (refractive index in this description) depend on the orientation of the material.

The match or mismatch between the refractive index of the matrix material and that of the second phase material is important. Such matching or mismatching is intentionally selected by appropriate selection of the materials used and is initially set by a priori or used initially, for example, through phase separation, (photo-induced) polymerization, heat treatment, removal of materials or combinations thereof. It can be implemented in situ after the conversion of the prepared material.

To illustrate this, reference is made to the example of FIG. 3A in which two phases show anisotropy, for example by using LC molecules as nematic or smectic phases. The alignment conditions of the two phases are chosen such that the matrix consists of vertically oriented LC molecules (indicated by a cross-shaped circle in FIG. 3A), while the dispersed phase consists of LC molecules oriented in a plane with left and right orientation. Selecting the material such that the normal refractive index of the matrix material matches the normal refractive index of the dispersed phase does not experience an effective refractive index mismatch when the linear polarization state of the incident beam is parallel to the order of orientation of the LC molecules in the dispersed phase. However, a mismatch between the normal refractive index of the matrix and the special refractive index of the dispersed phase scatters the polarization direction. Since the viewer cannot distinguish between different polarization states, the appearance of the film may be opaque in the region where the conditions as shown in FIG. 3A are met. By patterning the cover layer, for example, by creating an area having an orientation as shown in FIG. 3A and an area processing the arrangement as shown in FIG. 3B, without storing information or reading stored information in an underlying layer The information can be placed on a cover disk that can be read by the naked eye. Since this principle can be applied to both sides of the double-sided disk, the storage capacity can be doubled without sacrificing the printability of the disk (ie, the information storage capacity of the user information layer).

The foregoing example is for illustrating the above concept. Alternatively, the normal refractive index on the matrix does not match the special refractive index of the dispersed phase, maintaining the direction of linear polarization that experiences scattering.

As shown in Figures 3C-3F, other alignment arrangements are also feasible. While at least one phase should exhibit anisotropic alignment, it is not necessary for the second phase-the matrix or the dispersed phase-to have anisotropy. If the anisotropic refractive index of the isotropic phase matches any of the refractive indices of the anisotropic phase (e.g., Figures 3E and 3F), scattering is still observed to a lesser extent than can be observed for the arrangement shown in Figure 3A. do.

In addition, although the shape of the dispersed phase is not limited to the droplet shaped region (as shown in FIG. 4A), as shown schematically in FIG. 4B, it is a continuous (eg, interpenetrating network) character or a double continuation (eg For example, set, aggregate).

A form consisting of a continuous phase (matrix) and a second phase having a continuous, bicontinuous, preferably distributed character (area) has been described in the quarter.

For example, a so-called polymer dispersed liquid crystal (PDLC) consists of an isotropic or anisotropic polymer matrix and a dispersed liquid crystal phase (eg, as shown in FIG. 3E), for example, Fergason, J.L., SID DIG. Tech. Pap., 16, 68 (1985).

Such systems are typically produced in situ using phase separation techniques. Starting with a homogeneous mixture of monomers and inert liquid crystals, phase separation is thermally induced by vaporization of co-solvent (solvent induced phase separation: SIPS) or by photochemical means (polymerization or chemically induced phase separation: PIPS / CIPS). do.

In this process, phase separation occurs in the polymer rich region and the polymer lean region, and the final form can be precisely adjusted according to the appropriate treatment conditions. The dispersed low molecular weight LC phase thus obtained can be pretreated with a desired alignment—optionally different from the alignment of the matrix—for example using an electric or magnetic field.

Other mixtures of inert or reactive LCs and polymers are also described, for example, mixtures of LCs and flexible polymers [Fegason, J.L., SID Dig. Tech. Pap., 16, 68 (1985)], side chain liquid crystal polymers [Coles, J. J., J. Chem. Soc. Faraday Discuss., 79, 201 (1985), backbone liquid crystal polymers [Wilderbeek, H., PhD-Thesis, Eindhoven University of Technology (2001); H.T.A., Van der Meer, M.G.M., Bastiaansen, C.W.M., Broer, D.J., J. Phys. Chem. B, 106, 12874 (2002)], an isotropic or anisotropic networked structure [Drzaic. P.S., "Liquid Crystal Dispersion", World Scientific, Singapore, 1995, and Hikmet, R.A.M., J. Appl. Phys., 68, 4406 (1990)] or dispersed polymer particles [Van Boxtel, M.C.W., Janssen, R.H.C., Broer, D.J., Wilderbeek, H.T.A., Bastiaansen, C.W.M., Adv. Mater., 12. 753 (2000). Examples of the present invention are not limited to the use of organic (polymer) phases, as inorganic phases can be used (Eidenschink, R., De Jeu, W. H., Electronics Letters, 27, 1195 (1991)).

A variety of materials can be used to form the content information layer, and it can be seen that the material is used to form a matrix or region (domain or zone). For example, if desired, the materials forming the matrix and / or region may each be substantially transparent to visible radiation. Alternatively, one or more of the materials may be colored under visible or fluorescent radiation, for example the material is a dye. Such colored materials may be isotropic or anisotropic. By providing such a dye, a content information layer having a colored appearance can be produced.

Separating the fixation of the matrix from the fixation of the dispersed phase can be accomplished using the techniques described above. For example, an isotropic or anisotropic (e.g., side chain liquid crystal polymer; SCLCP) polymer matrix and reactive LCs are dissolved in the co-solvent, and the co-solvent is vaporized to produce the desired form, and the reactive LC phase undergoes light induced polymerization. To a desired alignment.

Alternatively, in a second non-limiting embodiment, the isotropic or anisotropic monomer is mixed with the anisotropic monomer to form a homogeneous phase. When the first monomer polymerizes, for example, photo-chemical phase separation takes place to produce the desired form. Thereafter, the second monomer is thermally polymerized. Between these two polymerization stages, reorientation of one or two phases can optionally be effected by external means such as electric or magnetic fields, shear forces, flow fields or alignment layers. For this purpose, LC materials with plus or minus dielectric anisotropy (Δε) can be used.

Separation mechanisms other than the thermal-photochemical mechanisms shown may also be developed, such as photo-polymerization at different wavelengths, photo-polymerization using different polarization states, polymerization at different temperatures, and the like.

In addition, fluidization-passivation methods may be employed using primary or secondary phase transitions or glass transitions in combination with low or high speed (eg quenching) heating or cooling.

In all cases, additives such as thermal initiators, photoinitiators, inhibitors, radical scavengers, chain transfer agents, stabilizers, surfactants, photosensitizers, dopants, isotropic or anisotropic (fluorescent) dyes, or combinations thereof may be used.

Preferred initial alignment of the anisotropic phase can optionally be realized by using an alignment layer (eg, mechanically aligned, photo-chemically induced), surfactant, electric field or magnetic field, shear force or flow field. For this purpose, the cover layer is optionally interposed between transparent electrically conductive layers such as indium tin oxide (ITO), which can be optionally covered with an alignment layer.

Based on the teachings herein, various methods of manufacturing the content information layer may be apparent to those skilled in the art. Compared to the manufacture of optical data storage media such as optical disks, four different methods of making such layers will be described.

Method 1

In the first embodiment, the alignment layer is deposited on the outermost layer having a reflective function such as metal in the optical data storage medium. The alignment direction of the alignment layer is mechanically induced by rubbing the alignment layer in a circular motion manner. This is realized by the rotation of the substrate when in contact with a device that enhances its alignment, such as velvet fabric. Thereafter, a spacing layer is provided by depositing spacers (eg, foils, beads, or rods optionally embedded in adhesive) on the edges of the disc and / or at different predetermined locations on the disc, which is anisotropic. Determine the final thickness of the layer.

Next, as schematically shown in Fig. 5A, a mixture of low molecular weight reactive liquid crystal (LC) and side chain liquid crystal polymer (SCLCP) is deposited on the optical storage medium in a state overlapping with the alignment layer.

Low molecular weight reactive LCs can form crosslinking networks during polymerization, such as LC monomers, or LC diacrylates (e.g., C3M in Figure 5B, multifunctional LC methacrylate) monomers or multifunctional LC siylene monomers. Consisting of a mixture of monomers with plus Δε. The side chain liquid crystal polymers consist of a temperature transition polymer having a glass transition preceding on one or more enantiotropic LCs, said transition temperature being below the ductility or degradation temperature of the optical data storage medium substrate. Photoinitiators and / or other additives as disclosed herein are added to the low molecular weight LC monomers. In order to obtain the desired form, for example, a mixture such as a phase separation mixture is deposited as such, or a mixture such as an isotropic mixture is deposited and subjected to high or low speed cooling or vaporization of a co-solvent.

Next, a reusable substrate provided with a transparent electrode or a structured transparent electrode (for example, ITO) in the shape of an image that can be visually determined by the consumer is placed on top of the mixture, and the substrate and the optical data storage medium are spacers. Is pressed until movement is limited. It is preferable that an orientation layer is apply | coated on a transparent electrode. Deposition of the covering electrode is preferably carried out before the desired form of the LC layer is obtained, but may be carried out during or after the obtained form. Thereafter, an atmospheric period optionally associated with the heating step may be employed to minimize or eliminate the presence of disclination within the LC layer.

The low molecular weight LC component is cured using UV initiation or thermal initiation to fix the previously obtained form or to obtain the desired form in-situ by induced phase separation. In the case of obtaining the desired form in-situ by induced phase separation, the final form is determined by various parameters such as the polymerization kinetics, for example changing the exposure conditions (radiation intensity, exposure time) or the thermal conditions ( Temperature, time) may be affected.

The non-axially aligned obtained LC layers composed of individual phases having the same refractive index are still transparent to both the laser beam and the user. The mismatch of the local unidirectional refractive index required is caused by applying an electric field on the LC layer and at the same time heating the layer to a temperature at which the SCLCP exhibits a semicrystalline phase below the soft or deteriorated temperature of the medium. The side chain substituents of the SCLCP reorient along the electric field line and establish a refractive index mismatch, which is fixed by low or high speed cooling of the LC layer while the electric field is maintained. If a new local orientation is established and the temperature is below the glass transition of the SCLCP, the electric field can be removed.

It should be noted that the electric and thermal fields can be applied locally by patterning of the electrodes or by selective addressing of the electrodes, or by using the thermal profile of the focused laser beam. An electric field is applied between the removable upper electrode and the information (metal) layer.

Finally, the substrate with the electrodes may be optionally removed and reused for another substrate to increase reproducibility and reduce cost, optionally covering a conventional data storage medium comprising a content information layer with a protective layer. Can be. All of the above steps may be performed side by side in order to increase the manufacturing speed.

Method 2

Similar to the state described for Method 1, a mixture of two different reactive fluid droplets with positive dielectric anisotropy is used, and the monomers can be polymerized individually and independently. For this purpose, for example, the LC component can be used photochemically (e.g. using onium salts for epoxides, oxetane or vinyl ethers, or type I or acrylates, methacrylates or While the other components are thermally (eg, free radical polymerization of acrylates, methacrylates, vinyl monomers or styrene). Inducing thermal initiator).

The derived form, for example the form obtained by the method described in the detailed description herein, is fixed by selective polymerization of one of the LC monomers (for example using UV-light) and subsequently remaining Unreacted LC monomer (single or plural) is redirected using an electric field applied through the structured electrode and unreacted components using different polymerization mechanisms (e.g. temperature increase or using light as the second wavelength). Fix it. Alternatively, the final form is obtained during the polymerization of the first LC component (single or plural).

Method 3

Similar to the state described for Method 2, low molecular weight LC fractions consist of LC monomers having negative dielectric anisotropy (Δε <0) or mixtures thereof, which monomers can be polymerized individually and independently. . Reorientation of the second phase, which has not yet been fixed, is carried out using an electric field in which the molecules are redirected in planar alignment. Preferred alignment may optionally be carried out using structured electrodes, dopants, or protrusions that cause in-plane electric fields.

Method 4

Under the same conditions as described for method 3, the (fluorescent) anisotropic dye is dissolved in one or both of the LC monomers or monomer mixtures. For example, following the procedure described in Method 3, after reorientation, the contrast visible to the human eye results in different anisotropic absorption areas of the anisotropic dye.

Embodiments of the present invention include an apparatus arranged to record content information in a content information layer of an optical recording medium, for example, by changing the second image to a predetermined orientation during in-situ on the recording medium. In this case, the optical recording medium includes a material that can be recorded to provide a predetermined area. Such a device may perform the same function as an injection device.

6 shows an apparatus 1 for scanning an optical recording medium 2 according to an embodiment of the present invention. The recording medium includes a transparent layer 3, on which a user information layer 4 is arranged. The medium includes a content information layer as described above. The content information layer is formed as part of the transparent layer 3. The side of the user information layer facing away from the transparent layer is protected from environmental influences by the protective layer 5. The side of the transparent layer facing the device is referred to as entrance face 6. The transparent layer 3 serves as a substrate for the recording medium by providing a mechanical support for the user information layer.

Alternatively, the transparent layer has a function of protecting the user information layer, and the mechanical support is a transparent layer connected by a layer on the other side of the user information layer, for example by the protective layer 5 or to the user information layer 4. And another user information layer.

The user information may be stored in the user information layer 4 of the recording medium in the form of optically detectable marks arranged in substantially parallel tracks, concentric tracks or spiral tracks, although not shown in the figure. The marker may be in an optically readable form, such as a pit form, an area having a different reflection coefficient or magnetization direction than its surroundings, or a combination of these forms.

The scanning device 1 has a radiation source 11 capable of irradiating a radiation beam 12. The radiation source may be a semiconductor laser. The beam splitter 13 reflects a radiation beam 15 diverging towards the collimator lens 14, which converts the diverging beam 12 into a collimated beam 15. The collimated beam 15 is incident on the objective system 18.

The objective system may include one or more lenses and / or gratings. The objective system 18 has an optical axis 19. The objective lens 18 converts the beam 17 into a converging beam 20 and enters the entrance face 6 of the recording medium 2. The objective system has a spherical aberration correction suitable for the passage of the radiation beam through the thickness of the transparent layer 3. The converging beam 20 forms a spot 21 on the user information layer 4. The radiation reflected by the user information layer 4 forms a beam 22 that diverges, which is converted into a beam 23 that is substantially collimated by the objective system 18, and the collimator lens 14. Is converted into a beam 24 that converges. The beam splitter 13 separates the forward beam and the reflected beam by transmitting at least a portion of the converging beam 24 towards the detection system 25. The detection system traps radiation and converts it into an electrical output signal 26. The signal processor 27 converts this output signal into various other signals.

One of the signals is a user information signal 28, the value of which indicates user information read from the user information layer 4. The information signal is processed by the error correction information processing unit 29. Other signals output from the signal processor 27 include a focus error signal and a radial error signal 30. The focus error signal represents the axial height difference between the spot 21 and the user information layer 4. The radial error signal represents the distance in the plane of the user information layer 4 between the center of the stack and the spot 21 in the user information layer following the spot.

The focus error signal and the radial error signal are supplied to the servo circuit 31, and these signals are converted into servo control signals 32 for controlling the focus actuator and the radial actuator, respectively. The actuator is not shown in the figure. The focus actuator controls the position of the objective system 18 in the focus direction 33 to control the actual position of the spot 21 to substantially coincide with the plane of the user information layer 4. The radial actuator controls the position of the objective lens 18 in the radial direction 34 to control the radial position of the spot 21 to substantially coincide with the centerline of the track following the user information layer 4. . In the figure the track extends in a direction orthogonal to the plane of the figure.

The scanning apparatus in this embodiment is also configured to scan a second type of recording medium having a transparent layer thicker than the recording medium 2. The apparatus may use a radiation beam having a different wavelength for scanning the radiation beam 12 or the second type of recording medium. The NA of this radiation beam may be suitable for this kind of recording medium. Therefore, spherical aberration correction of the objective system must be adapted.

The radiation beam incident on the optical recording medium 2 has a predetermined polarization. This can be accomplished in a variety of ways, for example it can be placed at any point in the beam path. In most cases, however, a laser (eg a laser diode) is used as the radiation source 11, which generally produces a linearly polarized radiation beam.

By providing a content information layer as described above, embodiments of the present invention apply this layer to one or both sides of both sides of the optical recording medium without inhibiting reading information from the user information layer on the optical recording medium. do. This enables rapid identification of the medium and / or quick identification of user information stored on the medium.

7 shows another embodiment of a recording medium 702 according to the present invention. The content information layer 706 is provided on the entrance face of the substrate 703. The content information layer includes a plurality of colored subregions 706r and 706g that have a predetermined area and are substantially equally spaced and substantially opaque. Suitable materials for the colored subregions include, for example, widespread, strongly colored ink dots. The ink dot has a light transmittance that is zero or nearly zero with respect to the first radiation. Steel pigments with sufficient absorbency at the first radiation wavelength may be used. Examples of dyes are mentioned in the description of FIG. 1. The colored subregions 706, 706r and 706g preferably have a size of 75 to 20000 μm 2. The subregions may be substantially circular and may have other shapes, for example square, rectangular or honeycomb shapes. The colored subregion occupies the content information layer zone at a selected value of 10 to 30% of the whole, and is distributed substantially uniformly above the content information layer zone. This percentage may be referred to as coverage. In the embodiment of FIG. 7, the circular ink dots have a surface area of about 314 μm 2 corresponding to a radius r of 10 μ, and are evenly spaced at 5 * r = 50 μm. This results in a coverage of π / 52 = 12.5%. The ink dot has zero transmittance with respect to the first radiation. Therefore, this percentage represents the light transmittance of the content information layer for the first radiation. Diffraction effects were not considered and can be ignored. The height of the ink dot is generally about 5 to 20 μm, and in this embodiment, it is about 5 μm. The matrix of ink dots 706 represents visible images 706g and 706r because not all ink dots have the same color. In the embodiment of FIG. 7, a content information layer 706 (and 706 on the opposite side) is disposed on the substrates 703b, 703a. Deposition can be performed by known deposition print techniques such as tampons, silk screen prints and ink jet prints. In FIG. 7, the disk 702 is on both sides and thus has two separate user information layers 704a, 704b mounted on either side of the individual layer or on the substrate 705. Each of the user information layers 704a and 704b is scanned by providing a beam of radiation incident on each of the user information layers 704a and 704b through the corresponding content information layer 706.

Fig. 8 shows another embodiment of an optical recording medium according to the present invention, in which the content information layer 806 is provided with a plurality of different colored sublayers 806g, 806r, and 806p that transmit substantially uniformly to the first radiation. 806b, 806y). The thickness of the colored sublayer is usually about 2 μm. The colored sublayers represent visible images, eg labels. The user information layer 804 is scanned by providing a beam 810 of first radiation incident on the user information layer 804 through the content information layer 806. The content information layer 806 has a substantially uniform light thickness at the first radiation wavelength so as not to interfere with reading information from or writing information to the user information layer 804 of the optical recording medium at the first radiation wavelength. . This is accomplished by the presence of a substantially optically transparent and flat cover layer 806t facing away from the user information layer 804. The cover layer is thick enough to obtain a flat top surface, ie to flatten the gaps and differences between the colored subregions. The total thickness of the colored subregions and cover layer may be 2 to 3 μm, but other thicknesses are not excluded. Another layer 805 is provided for protection of the user information layer 804. Another layer 805 may also comprise the other half of the double-sided disc comprising the second content information layer according to the invention (compare with reference numeral 706 of FIG. 7). Sublayers 806g through 806y are colored and deposited according to a predetermined visible image by known printing techniques. Transparent cover layer 806t may be deposited, for example, by spin coating.

Claims (22)

At least one content information layer and at least one user information layer arranged to be scanned by the first radiation through the content information layer, wherein the content information layer includes at least one area representing content information in a peripheral medium. Wherein the content layer transmits first radiation, and wherein the region and the peripheral medium provide an optically visible contrast to different second radiations. The method of claim 1, Wherein said at least one area has a first transmittance for first radiation and a low second transmittance for second radiation. The method according to claim 1 or 2, And said first radiation has a first predetermined wavelength and said second radiation has a different second wavelength. The method according to claim 1 or 2, Wherein the first radiation has a first predetermined polarization and the second radiation has a different second polarization. The method of claim 4, wherein The area comprises at least one birefringent material, wherein the birefringent material passes at at least two different refractive indices when the second polarized radiation crosses the content information layer, while the first polarized radiation crosses the content information layer. Wherein the optical recording medium is arranged to pass at substantially a single index of refraction. The method of claim 5, And said birefringent material is dispersed in a matrix material. The method according to any one of claims 1, 2, 3 or 4, And the content information layer comprises a dye. The method of claim 4, wherein And the dye is birefringent. The method of claim 1, And the area is patterned or arranged in a predetermined manner to provide visibility content information to a user. The method of claim 9, And the content information layer includes a plurality of colored sub-areas that are substantially uniformly spaced and substantially opaque. The method of claim 10, And the colored sub-area has a size of 75 to 20000 m ² . The method of claim 11, And the colored sub-area occupies the content information layer zone at a value selected from 10 to 30% of the total, and is substantially evenly distributed above the content information layer zone. The method of claim 9, And the content information layer comprises a plurality of different colored sublayers substantially uniformly transmissive to the first radiation. The method of claim 13, Wherein the content information layer has a substantially uniform light thickness at the focused radiation wavelength while writing or reading information from or to the user information layer of the optical recording medium at a first radiation wavelength. The method of claim 14, And the content information layer further comprises a substantially optically transparent and flat cover layer facing away from the at least one user information layer. The method of claim 9, Wherein said content information layer comprises a dielectric layer having antireflective properties at a first radiation wavelength, said dielectric layer representing visible content information. The method of claim 1, Wherein the recording medium is double sided, at least one side having a content information layer and each side having a user information layer. The method of claim 1, And at least one region, wherein the region comprises at least one of claims 6, 7, 8, 9, 10, 11, 12, 13, 14 and 14. 18. An optical recording medium combining at least two or more of the configurations according to any one of claims 15, 16 or 17. At least one content information layer and at least one user information layer arranged to be scanned by the first radiation through the content information layer, wherein the content information layer includes at least one area representing content information in a peripheral medium. And a recordable material in a providing pattern, wherein the content layer transmits first radiation, and wherein the area and the peripheral medium provide optical contrast to different second radiations. A recording apparatus for recording content information in a content information layer on an optical recording medium, The optical recording medium, At least one content information layer and at least one user information layer arranged to be scanned by a first radiation through the content information layer, the content information layer comprising a recordable material, Wherein the recording device is arranged to record the material of the content information layer to provide at least one area in the pattern direction representing the content information, wherein the area and the peripheral medium provide optical contrast for different second radiations. Recording device. A recording method for recording content information on an optical recording medium comprising at least one content information layer comprising recordable material and at least one user information layer arranged to be scanned by first radiation through the content information layer. In Recording the material of the content information layer to provide at least one area in the pattern direction representing the content information, And the area and the peripheral medium provide optical contrast for different second radiations. In the method for manufacturing an optical recording medium, Providing at least one user information layer arranged to be scanned by the first radiation, Providing at least one content information layer comprising recordable material to provide at least one area representing content information, And said area and peripheral medium provide optical contrast for different second radiations.

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