Abstract: A copper alloy plumbing fixture containing interdispersed lead particles coated non-continuously on a water contact surface to resist the leaching of lead into potable water systems. The leach resistant fixture is prepared by immersing conventional copper alloys in a bismuth nitrate solution, selectively and non-continuously coating the lead dispersoid particles on the water contact surface with bismuth, tin or copper.

Abstract: Various configurations of a directed energy assisted micro embossing machine/station in a vacuum chamber utilized in a continuous manufacturing process and the web structure products made by that process (optical disks, cards, tapes, holographic reflectors, diffusers, binary optical elements, etc.) are disclosed. The configurations can include a single machine roll to roll system for embossing optical features on the surface of a single substrate and applying appropriate metallic, dielectric, semiconductor, polymer and other coatings all in a vacuum chamber.

Abstract: An optical information recording medium for recording, retrieving and erasing mark length-modulated amorphous marks, which comprises a substrate, and a lower protective layer, a phase-change recording layer, an upper protective layer and a reflective layer having a thickness of from 40 to 300 nm and a volume resistivity of from 20 to 150 n.OMEGA..multidot.m, formed in this sequence on the substrate.

Abstract: A transparent simulation disk for measuring flying height of a magnetic head (i.e., distance between a magnetic head and a magnetic disk such as a hard disk of a computer) in place of a magnetic disk is made of a SiO.sub.2 --R.sub.2 O (where R is Li, Na or K) glass or glass-ceramic having electric resistivity of 10.sup.8 -10.sup.14 .OMEGA.cm and abrasion of 90 or below.

Abstract: A substrate for an information recording medium is prepared from a glass substance having a Young's modulus not smaller than 100 GPa and a liquidus temperature not higher than 1350.degree. C.

Abstract: A phase change optical recording medium includes a phase change optical recording layer which transits between two states of the crystalline state and the amorphous state when irradiated with light, and a heat adjustment layer which is formed adjacent to the phase change optical recording layer and abruptly increases or decreases thermal conductivity with increasing temperature upon irradiation of recording light. This phase change optical recording medium can decrease the size of the recording mark and makes high-density recording possible.

Abstract: A dual layer pre-recorded optical disc includes a transparent substrate, a partially reflective layer, a transparent spacer layer, and a highly reflective layer. One pattern of data pits is provided on the substrate, adjacent the partially reflective layer, and another pattern of data pits is provided on the spacer layer, adjacent the highly reflective layer. The transparent spacer layer comprises at least two sublayers. The partially reflective layer may be made of silicon carbide. A substrate-incident beam can be used to read data encoded in either data pit pattern depending on which layer the laser is focused upon. The dual layer disc has twice the data storage capacity of conventional single layer discs.

Abstract: A multilayer optical disk having an information storage layer which can as well as be reproduced by a general purpose reproducing apparatus, for example, a compact disk player, and from which information can be read from other information storage layers by using an exclusive reproducing apparatus. The multilayer disk has a first substrate on which is formed a first information storage layer which is relatively highly reflective with respect to a light beam having a wavelength of 770-830 nm; and a second substrate on which is formed a second information layer which is relatively transparent with respect to a light beam having a first substrate on which is formed a wavelength of 770 mn to 830 nm but which is sufficiently reflective with respect to a light beam having a wavelength of 615-655 nm.

Abstract: A method for forming a protective barrier layer between the active dye layer and the disc substrate during production of an optical memory disc is provided wherein a pre-treatment/pre-coat solution is applied to the disc substrate. This pre-treatment/pre-coat solution includes a surface modifier having an index of refraction approximately equal to that of the disc substrate. Surface modifiers utilized in this pre-treatment/pre-coat solution include poly vinyl alcohol, poly alpha methyl styrene, cellulose acetate, poly vinyl butyral and nitrocellulose.

Abstract: A method for seeking, from an outer circle radius a, an inner circle radius b, and a thickness h of a disc substrate and a deflection Wmax permissive at a time of rotation, a specific elastic modulus G that a material forming the substrate has, ##EQU1## The material for providing a substrate for information recording media having a thickness h of 0.6 millimeter and a deflection Wmax of 1.4 micrometer has a specific elastic modulus G satisfying above Formula (1).

Abstract: A magnetic recording has very low warp characteristics but excellent film characteristics. Particularly, the recording medium has a high coercivity with a small range of coercivity distribution, with a warp characteristic below 3 .mu.m per radial inch. The medium is formed by heating a substrate at a high temperature with a temperature distribution on the substrate that is improved by the use of a heat distribution mask, which reduces the temperature distribution of the substrate to below .+-.3%.

Abstract: The invention pertains to an optical recording medium comprising a homeotropically oriented liquid crystalline polymer film having a T.sub.g between 75-100.degree. C. and a T.sub.c between 110-140.degree. C. and comprising at least one dichroic dye. This homeotropic orientation along with the presence of dichroic dye makes it possible to employ a different technique for writing out and reading data. For, in this case contrast is obtained by the dichroic dye contained in the film being aligned in the same direction as the mesogenic groups of the liquid crystalline polymer. In a virgin film the mesogenic groups, and hence the dichroic dye molecules, are oriented perpendicular to the film's surface, and there is only low absorption of the incident light by these molecules. By local heating or irradiation of the film (e.g., with a laser) the homeotropic orientation is converted to an isotropic one.

Abstract: A highly reliable information recording medium capable of meeting a higher rotation speed of a drive device and a smaller thickness and a higher recording density of an information recording medium can be produced by using, as a substrate, chemically reinforced glass obtained from chemically reinforceable glass having an SiO.sub.2 --Al.sub.2 O.sub.3 --R.sub.2 O total content of more than 98% by weight and having a specific modulus of at least 30.times.10.sup.2.

Abstract: A side chain liquid crystal polymer and a manufacturing method therefor are provided. Also, an optical recording medium of which recording layer is made of the side chain liquid crystal of the present invention is provided. The side chain liquid crystal polymer expressed by the following formula (V) has excellent processing properties due to its high solubility. Also, due to its high glass transition temperature and low polydispersity, information recorded on a recording layer made of the polymer can be preserved for a long time. In addition, since the recorded type (pit) is even, the error rate is low and the occurrence of jitter noise can be remarkably reduced: ##STR1## where A is either CH.sub.2 or CH.sub.2 --O--(CH.sub.2).sub.m, R is either OCH.sub.3, CN or NO.sub.2, l is 10 to 100, m is 1 to 6, and n is to 20.

Abstract: An optical data storage medium transmissive to a laser beam and formed of a light transmissive substrate that provides mechanical support, and a light transmissive data substrate formed on the substrate. The data substrate is patterned to form block regions that block the laser beam from passing through, and pass regions that allow the laser beam to pass through, such that the blockage or passage of light through the optical storage medium reflects the type of data bits to be stored on the optical medium. In another embodiment a magneto-optical data storage medium which is also transmissive (or partly transmissive) to a laser beam includes a data magneto-optical data substrate formed on a substrate. The data substrate is recordable by patterning a magnetic domain with magnetic fields of opposite directions, such that each magnetic direction reflects the type of data bits to be stored on the optical medium.

Abstract: An optical recording medium has a phase-change recording layer embedded in a stack of thin layers arranged on a substrate. At least one of the dielectric layers adjacent to the recording layer comprises a carbide. The carbide layer is separated from the substrate and/or from a reflecting layer in the stack by a dielectric layer not containing a carbide. The thickness of the carbide layer either lies in a range from 2 to 8 nm or is substantially equal to the thickness of the adjacent dielectric layer.

Abstract: Disclosed is a method for storing and retrieving information. More specifically, the present invention is a method for forming predetermined patterns, or data structures, using materials which exhibit enhanced absorption of light at certain wavelengths or, when interrogated with a light having a first wavelength, provide a luminescent response at a second wavelength. These materials may exhibit this response to light inherently, or may be made to exhibit this response by treating the materials with ionizing radiation.

Abstract: In the optical recording medium including a substrate having pregrooves, and a metal recording layer, a buffering layer, a reflecting layer and a protecting layer which are sequentially stacked on the substrate, wherein the buffering layer is formed of an organic material having a low light absorption with respect to a laser beam of 600.about.800 nm, such that light absorption (k) is less than or equal to 1.0 at 650 nm and the light absorption (k) is less than or equal to 0.1 at 780 nm. Therefore, the optical recording medium can be compatible with a compact disc (CD) and have a high reflectivity at longer wavelength than 600 nm.

Abstract: A dye composition for use in optical recording media, comprising at least one cyanine dye having an anion selected from the group consisting of thiocyanate, lactate, hypophosphite, tetracyanonickelate, selenocyanate, trifluromethanesulfonate, ferricyanide, 4-hydroxybutyrate, nitrite, 2-(3',5'-dimethyl-2'-hydroxyphenyl)-2H-benztriazole-4-sulfonate, 1,2-napthoquinone-2-diazide-5-sulfonate and picrate and preferably dissolved in ethyl lactate.

Abstract: A writable compact disk has a plastic substrate, a recording layer, a reflecting layer, and a protective overcoat, the reflecting layer is comprised of a silver-palladium alloy, a silver-copper alloy, or a silver-palladium-copper alloy. By maintaining the palladium component of the alloy less that 15 at. % and the copper component of the alloy less than 30 at. %, the reflectance of the reflecting layer can be similar to the typical gold reflecting layer while jitter and NORP levels can be reduced for illumination power levels exceeding the power normally used to write on the recording layer.

Abstract: An optical recording medium includes a substrate, a first protection layer formed on the substrate, a recording layer formed on the first protection layer, a second protection layer formed on the recording layer, and a reflection heat radiating layer formed on the second protection layer. The recording layer is of a phase-change type in which the recording layer is changed from an amorphous state to a crystal state by a temperature raising and cooling process by projecting a laser beam onto the recording layer. The recording layer has an interface portion interfaced with one of the first and second protection layers. The interface portion has a thermal conductivity lower than that of a remaining portion of the recording layer.

Abstract: Method and apparatus for producing a bonded composite disk including a first and a second disk component which are bonded together, using a mold including a first mold half having first concentric elements whose axial end faces cooperate with an annular information-bearing stamper or an annular blank stamper, to provide a first molding surface, and a second mold half having a second concentric elements whose axial end faces provide a second molding surface cooperating with the first molding surface to define a cavity for forming each of the first and second disk components.

Abstract: An optical information recording medium which records at shorter laser wavelengths and has excellent light resistance and archival stability includes a supporting substrate and a recording layer coated on the substrate. The recording layer includes a metal chelated azo compound, the azo compound having the general formula (I): ##STR1## wherein X is NR.sup.6 group, oxygen or sulphur, wherein R.sup.6 is hydrogen or alkyl; Y is hydroxy, carboxy, or carbamoyl; each of R.sup.1 -R.sup.5 is independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkenyl, alkoxy, amino, halogen, nitro, cyano, trifluoromethyl, or carboxy, with the proviso that all of R.sup.1 -R.sup.5 are not simultaneously hydrogen; and the metal is a metal ion of Groups 3-12 of the Periodic Table.

Abstract: To protect the optical surface of optical disc information recording media such as a compact disc (CD) or a digital versatile disc (DVD), that surface is coated with a removable layer of a material that does not significantly alter the optical properties of the disc. Whenever the coating layer may have become damaged, it is removed and replaced with a new layer.

Abstract: A description is given of an reversible optical information medium comprising a substrate, a first dielectric layer, a phase-change recording layer on the basis of Ge--Sb--Te, a second dielectric layer, and a metal mirror layer. The recording layer comprises an alloy having the composition Ge.sub.50x Sb.sub.40-40x Te.sub.60-10x in atom %, wherein0.166.ltoreq.x.ltoreq.0.444and wherein the layer thickness d.sub.3 of said recording layer ranges between 25 and 35 nm. Such a medium is suitable for high speed recording (i.e. at least twice the CD-speed), and has a large cyclability of at least 10.sup.5 direct overwrite cycles.

Abstract: The present invention discloses an optical recording element having, in the following order, a transparent substrate, a recording layer and a light reflecting layer wherein the recording layer(A) has a real refractive index (N) at 780 nm not less than 1.8 and an imaginary part (k) is not greater than 0.15;(B) comprises a polymeric cyanine dye that (i) has both a weight-average molecular weight greater than 50,000 and a glass transition temperature (Tg) of less than 150.degree. C.; or (ii) has either (a) a weight-average molecular weight greater than 50,000 or (b) a glass transition temperature (Tg) of less than 150.degree. C.; and(C) a thickness greater than 200 nm.

Abstract: A process for fabricating a magnetic data storage medium includes formation of a controlled texture, either over an annular transducing head contact area or the entire surface of a substrate. The texture layer is formed by vacuum deposition of a texturing material onto a smooth surface of a non-magnetic substrate. The texturing material has a surface energy greater than that of the substrate, and the texturing material and substrate material have different linear coefficients of thermal expansion. Just before deposition of the texture layer, the substrate is heated to a temperature of 200-600.degree. C., then allowed to cool during texture layer deposition. The substrate and texture layer contract at different rates as they cool, inducing mechanical stresses within the texture layer sufficient to plastically deform the texture layer, creating multiple dome-like bumps.

Abstract: The present invention is in the field of optical recording media, and is directed to an optical recording medium which comprises the following layers;a) a grooved transparent substrate (1), superposed byb) a recording layer comprising a partial mirror (2) of a material having a high complex index of refraction which is not within the pentagon defined by the vertices 7.15 - i3.93, 7.15 - i5.85, 8.96 - 6.28, 9.56 - i5.90, and 8.14 - i3.77 in the n,k plane, superposed by a buffer layer (3) comprising a nonliquid-crystalline high-molecular weight material and optionally a dye, superposed by a thick reflective layer (4), together forming a Fabry-Perot wherein the thickness (d) of the buffer layer within the grooves is set so that the reflection of the medium is in the high reflective state, optionally superposed byc) a protective coating (5).By virtue of the partial mirror, the buffer layer, and the thick reflective layer a Fabry-Perot etalon is created.

Abstract: An optical recording element is disclosed. The element has a transparent substrate and on the surface of said substrate, a recording layer and a light reflecting layer wherein recording layer comprises a mixture of a metallized formazan dye and cyanine dye and the unrecorded layer is such that the real part of the refractive (n) at 780 nm is greater than 1.8 and the imaginary part (k) is less than 0.15. The metallized formazan dye has a k value of 0.03 to 0.07.

Abstract: A glass substrate for a magnetic disk of the present invention is one in which a laser beam is irradiated on a magnetic recording surface side thereby forming a large number of protrusions thereon to form texture thereon, each of the protrusions having a convex shape, an optical absorption coefficient of a glass with respect to a wavelength of a laser beam at 266 nm being within a range of 20 to 2000 mm.sup.-1, the glass having a composition by weight of:silicon oxide (SiO.sub.2): 58 to 66%,aluminum oxide (Al.sub.2 O.sub.3): 13 to 19%,lithium oxide (Li.sub.2 O): 3 to 4.5%,sodium oxide (Na.sub.2 O): 6 to 13%,potassium oxide (K.sub.2 O); 0 to 5%,R.sub.2 O: 9 to 18% (provided R.sub.2 O=Li.sub.2 O+NaO+K.sub.2 O),magnesium oxide (MgO): 0 to 3.5%,calcium oxide (CaO): 1 to 7%;strontium oxide (SrO): 0 to 2%;barium oxide (BaO): 0 to 2%,RO: 2 to 10% (provided RO=MgO+CaO+SrO+BaO), andiron oxide (Fe.sub.2 O.sub.3): 0.05 to 2%,titanium oxide (TiO.sub.2): 0 to 2%,cerium oxide(CeO.sub.

Abstract: In a semiconductor assembly with a solder material layer and a method for soldering the semiconductor assembly, a silicon semiconductor body with a diffusion barrier layer is provided with a solder material layer, preferably a tin layer. The semiconductor body is then applied to a metal carrier plate and is directly soldered to the carrier plate by heating to temperatures to above 250.degree. C., i.e. without further additions.

Abstract: A glass substrate for magnetic disks, obtained by chemical strengthening treatment of a glass consisting essentially of from 50 to 65 wt % of SiO.sub.2, from 5 to 15 wt % of Al.sub.2 O.sub.3, from 2 to 7 wt % of Na.sub.2 O, from 4 to 9 wt % of K.sub.2 O, from 7 to 14 wt % of Na.sub.2 O+K.sub.2 O, from 12 to 25 wt % of MgO+CaO+SrO+BaO, and from 1 to 6 wt % of ZrO.sub.2.

Abstract: An optical information medium comprises a first disc forming information recording layer on a main surface thereof, a second disc being bonded to the first disc at the surface where the information recording layer is formed by way of an adhesive. A hydrophilic resin film is formed on the surface of the disc at the inner peripheral side extending from the center hole to the information non-recording area. The hydrophilic resin film is damp and is rough compared with the other portion formed of non-hydrophilic resin, and it is elastic. The characters, patterns or designs can be printed on the optical information medium using water-base ink, etc. after manufacturing the optical information medium. Further, the hydrophilic resin film is formed on the disc at the portion outside the information recording area.

Abstract: The present invention is an aluminum assembly comprising at least two components brazed to each other. The assembly comprises: at least a first aluminum based component having a coating of a zinc-antimony alloy having at least 1.0 wt. % antimony applied to a region of a surface of the component which is to be joined to a second aluminum based component; and at least one second aluminum based component disposed adjacent to the coating; whereby the at least first aluminum based component and the at least second aluminum based component are joined together during a controlled atmosphere brazing (CAB) process.

Abstract: One object of the invention is to achieve a phase change type optical recording medium having high degree of modulation and recording sensitivity, and another object of the invention is to achieve a phase change type optical recording medium having already stable write/read characteristics at the time of the first overwriting. The optical recording medium comprises a recording layer made up of an optical recording material containing given amounts of In, Ag, Te and Sb. In one Raman spectrum embodiment of the optical recording there are a scattering peak I-1 having a Raman shift in a range of 113 to 117 cm.sup.-1 and a scattering peak I-2 having a Raman shift in a range of 123 to 127 cm.sup.-1, said scattering peak I-2 being larger in half-width than said scattering peak I-1. In another Raman spectrum embodiment, there are a scattering peak II-1 having a Raman shift in a range of 105 to 125 cm.sup.-1 and a scattering peak II-2 having a Raman shift in a range of 140 to 160 cm.sup.

Abstract: An ion implant process is disclosed for forming an amorphous structure in a semiconductor metallization barrier layer, which barrier may be a pure metal barrier, such as titanium, tantalum, tungsten, or metal compound barrier, such as titanium nitride, or titanium-tungsten. The implant is preferably an ion of the barrier metal being used, which is implanted such that an amorphous (texture-less non-crystalline) layer is produced. Other implant species, such as nitrogen or noble gases, such as neon or argon may also be used. Subsequent deposition of the interconnect metallization (typically Al or Cu) results in an interconnect metal structure having a high degree of texture which is characterized by a very narrow distribution of crystallographic orientations in the Al or Cu film. The highly textured Al or Cu metallization results in optimizing the interconnect metal for maximum electromigration performance.

Abstract: A recordable optical disk including a transparent substrate; a recording layer formed over the substrate; a reflective layer formed over the recording layer; and a thin dielectric interlayer formed on the recording layer at the interface between the reflective layer and the recording layer wherein the thin dielectric interlayer includes materials selected from the group consisting of Ge--C--H, Si--N and InSnSb--O, the interlayer being selected so as to improve the optical disk recording stability without significantly affecting the reflection of a recording light beam passing through the substrate and the recording layer and which is reflected by the reflective layer.

Abstract: The optical information medium of the invention includes: a first substrate having a first information signal layer; a first reflective film formed on the first information signal layer of the first substrate; a second substrate having a second information signal layer; a second reflective film formed on the second information signal layer of the second substrate; and a photopolymer resin film provided between the first reflective film and the second reflective film for bonding the first substrate and the second substrate with each other.

Abstract: A dye mixture having, at 780 nm, a real refractive index not less than 1.8, and an imaginary part not greater than 0.15 and comprising (a) a tetra dye having a metallized azo dianionic dye with a cationic dye counterion and (b) at least one other dye having the structure according to formula I: ##STR1## wherein: A may be equal to or different from A.sup.1, in which each represents an aryl group having 6 to 10 carbon atoms;B may be equal to or different from B.sup.1, in which each ##STR2## R and R.sup.1 represent an alkyl group of C.sub.1 -C.sub.10 or an aryl group having 6 to 10 carbon atoms; andX represents halide, ClO.sub.4, BF.sub.4, PF.sub.6, tosylate and RCOO.

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.multidot.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.multidot.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.

Abstract: An optically readable data storage medium includes a thin film data carrier fabricated from first and second juxtaposed plastic layers. A microembossed data surface is positioned within an interface zone and includes physically displaced surface elements which encode digital data. An adaptor temporarily receives and supports the thin film data carrier from below and includes a centrally located aperture geometrically compatible with a standard CD player spindle to enable the adaptor to be supported and rotated by the spindle. The adaptor includes a refraction zone having an area and a location underlying the microembossed data surface to enable the light beam from the light source of the CD player to be focussed onto the rotatable data surface. The reflected light beam modulated by the digital data encoded within the microembossed data surface is intercepted and converted to an electrical signal by the CD player optical readout device.

Abstract: A method is described for altering the luminescence of a light emitting semiconductor (LES) device. In particular, a method is described whereby a silicon LES device can be selectively irradiated with a radiation source effective for altering the intensity of luminescence of the irradiated region.

Abstract: In an optical disk obtained by pasting two substrates, air bubbles and the like are removed from an adhesive layer between the substrates pasted together, and the thickness irregularity of the adhesive layer is suppressed to an allowable value or less. A spacer having a predetermined thickness is concentrically placed on a substrate. An adhesive is applied onto a surface of the substrate on which the spacer is placed. Another substrate is placed on the surface of the substrate on which the adhesive is applied. The substrates are rotated about the spacer at a high speed. The excessive adhesive sandwiched between the substrates is expelled, together with air bubbles and the like, by using the centrifugal force produced by the rotation. With this process, an adhesive layer having a thickness determined by the thickness of the spacer is left between the two substrates.

Abstract: An optical recording medium comprising a recording layer, a light interference layer, a reflective layer and a protective layer that are laminated on a substrate, characterized in that said recording layer and said light interference layer comprise at least one organic dye, and that a light absorbent and/or a thermal decomposition promoter are/is added to said light interference layer, wherein the optical recording medium has compatibility that allows good recording and/or reproduction by using lasers of different two wavelength ranges and has good recording properties.

Abstract: Improved disc metal mold provides an improved disc without a ring groove thereon. The improved disc metal mold has a fixed metal mold section and a movable metal mold section for forming a cavity therebetween. One of the fixed and movable metal molds has a stamper having an information signal surface on which an information signal is formed in a form of pits, wherein a fused resin is injected into the cavity to form a disc substrate having a center through hole at the center thereof. The disc metal mold includes the stamper having an center hole at a center thereof for retaining the stamper itself and a retainer for retaining the stamper to engage with the center hole of the stamper. The retainer has a slightly larger diameter at a top surface thereof than a diameter of the center hole of the stamper so that the top surface of the retainer is approximately flush with the information signal surface of the stamper by causing the top end thereof to engage with the center hole of the stamper.

Abstract: An optical recording medium capable of recording and/or reproducing an information by using a laser beam, comprising: a support layer having an information signal-recording portion on one side surface thereof on which said laser beam is incident, and a transparent layer disposed over the support layer and having a thickness smaller than that of the support layer. In accordance with the present invention, there are further provided production method for optical or magneto-optical discs whereby a high density reproduction can be achieved.

Abstract: An optical disk apparatus using an optical disk in which a layer (a reflectivity adjustment layer) in which the optical constants are changed by melting at the time of irradiation of light is provided separately from a recording layer using a phase change, and the reflectivity at a portion having a high reflectivity on the recording track is 40% or lower at the time of irradiation of strong light, and the reflectivity at the same portion is 60% or higher at the time of irradiation of weak light, wherein when the laser power is set to a power which is higher than the power at which the optical constants of the reflectivity adjustment layer are greatly changed at the time of rewriting and at which a high melting-point component is not melted, remaining of an unerased portion during rewriting due to a difference in reflectivity between the written mark portion and the other portions can be prevented and the possible number of rewritings can be increased, and hence an optical disk which has a high recording sensi

Abstract: A recordable element including a substrate and having over its surface, in order, an optical recording layer and a light reflecting layer, the improvement includes an optical recording layer containing Te.sub.a Ge.sub.b C.sub.c H.sub.d O.sub.e where a, b, c, d, and e are atomic percents such that a+b+c+d+e=100, and wherein 10<a<40, 10<b<60, 5<c<35, 10<d<5, e.gtoreq.0; an the optical recording layer having one or more sublayers which can be of different compositions; and the thickness t of the optical recording layer is 0.7 Tmin<t<1.3 Tmin.

Abstract: The present invention is relative to an optical information recording medium having a reflective layer for reading out information signals by an optical technique. The optical information recording medium is formed as a plastic substrate. According to the present invention, the substrate is colored by admixture of a dyestuff for enabling instant judgment by the visual sense of the operator as to the contents of the optical information recording medium, for example, as to if the contents of the recording medium is a game program or the music information. If impurities such as dyestuffs are admixed, the optical system of the readout device is usually affected thus raising readout difficulties. Such ill effects on the optical system may be eliminated by setting the particle size of the dyestuff so as to be 50 .mu.m or less.

Abstract: An optical element is provide which has a durability enhancing layer. There is provided an optical disk comprising a support having on one surface thereof, in order:a) a recording layer such that said recording layer does not cover the entire surface of said disk but leaves an annular portion at the outer diameter;b) a reflective layer such that said reflective layer does not cover the entire surface of said disk but leaves an annular portion at the outer diameter;c) a first protective layer having a thickness between about 2-20 .mu.m, said protective layer being of a material having good adhesion to said support and covering a portion of the surface of said disk having said reflective layer, including at least a portion of said annular portion;d) a second protective layer having a thickness of at least about 3 .mu.m, said second layer covering at least the area of said surface having the reflective layer and having good adhesion to said first protective layer.