Abstract: An optical information medium having a light transmission layer obtained by curing a composition containing a urethane di(meth)acrylate (A) of the formula (I) and the other urethane di(meth)acrylate (B), and having a tensile elastic modulus of 600 to 1300 MPa at 25° C. and a light transmittance of 80% or more at wavelength of 400 nm (in the formula, R1=an alicyclic diisocyanate residue, R2=an alkylene group or an organic group containing a cycloalkyl group or ester bond, R3=H or methyl group.

Abstract: The car power source apparatus is provided with a battery case housing a plurality of rechargeable batteries in a battery compartment, and air ducts to carry ventilating air to the battery case and cool the batteries. A plurality of air inlet and outlet openings are provided through panels between the battery compartment and the air ducts. Air inlet and outlet openings are opened in a direction different from the direction of airflow in the ducts. Further, the power source apparatus has a plurality of airflow channels of differing length established inside an air duct in the direction of airflow. This divides ventilating airflow in the air duct into a plurality of airflow channels.

Abstract: An increase in cost is minimized while realizing larger capacity. An optical disc 102 includes, from the bottom of the drawing: a substrate 104; a first information recording layer 108 formed on the substrate 104; and a first light transmission layer 110 having a thickness of about 20 ?m formed on the first information recording layer 108. A second information recording layer 114 is formed on the first light transmission layer 110, and a second light transmission layer 116 having a thickness of about 90 ?m is formed on the second information recording layer 114. A laser beam La is irradiated from the side of the second light transmission layer 116 to allow recording and/or reading of an information signal on/from the first and second information recording layers 108 and 114.

Abstract: The present invention provides a method of manufacturing an optical recording medium having two recording layers on a supporting substrate and an optical recording medium obtained according to the method.

Abstract: An optical disc cartridge is provided, which can accommodate an optical disc having a substrate and a light-transmitting layer thinner than the substrate and can suppress warpage of the optical disc within a predetermined limit value. The optical disc cartridge 32 is provided with an opening 20 on one side in a thickness direction and an opening 34 on the other side. An area of each opening is set to be ¼ or more of an area of the optical disc 16. Moreover, a ratio of the area of the opening 20 to the area of the opening 34 is set to be larger than ¼ and smaller than 4.

Abstract: Disclosed is a disc-shaped recording medium manufacturing method capable of making it difficult to leave the cutting wastage produced upon forming a notch for exfoliating a stamper on a disc-shaped substrate in the case of adopting a stamper-based transfer method, and surely forming the notch to improve a manufacturing yield. This disc-shaped recording medium manufacturing method is that a spacer layer having recording faces on both surfaces thereof is formed between the disc-shaped substrate and the stamper, a notch is formed in the vicinity of an outer peripheral edge of the stamper by a rotary blade of a circle cutter, and the stamper is exfoliated through the notch while the spacer layer stays on the disc-shaped substrate.

Abstract: A surface treatment of a light transmissive layer by spin coating is carried out in a simple way at low cost. When a light transmissive layer is to be formed by spin coating, the transfer of an information recording layer is carried out using a resin stamper having a convex portion in an outer peripheral portion. At the same time, an inclined plane (concave portion) is formed on the side of a substrate (member on which transfer is performed). As a result, coating is achieved in such a manner that a raise in the outer peripheral portion is prevented from being noticeable.

Abstract: A warpage angle measurement apparatus and a warpage angle measurement method are provided that can measure an angle of warpage of an optical disc and a cartridge for the optical disc caused by a rapid environmental change such as a temperature change or a humidity change in a short time. The warpage angle measurement apparatus 10 includes: a constant temperature chamber 22 for accommodating an optical recording medium 20 formed by mounting the optical disc 16 as an object to be measured in the cartridge 18 and for adjusting a surrounding of the optical recording medium 20 to have a predetermined environmental condition; a laser oscillator 24 for causing laser oscillation to emit laser light to the optical disc 16; and a light-receiving unit 26 for receiving the laser light reflected from the optical disc 16 and detecting a relative angle of an optical path L2 of the reflected laser light with respect to an optical path L1 of the emitted laser light.

Abstract: An optical recording medium includes a substrate, a protective layer, three or more information recording layers formed between the substrate and the protective layer and transparent intermediate layers each formed between neighboring information recording layers and capable of recording data in the three or more information recording layers and reproducing data recorded in the three or more information recording layers by projecting a laser beam onto the three or more information recording layers via a light incidence plane constituted by the surface of either the substrate or the protective layer, wherein neighboring transparent intermediate layers facing each other across an information recording layer have different thicknesses. According to the thus constituted optical recording medium, it is possible to reduce interlayer cross-talk.

Abstract: The invention provides an optical recording disk, with which the worsening of jitter can be prevented effectively even when fingerprints become adhered onto a laser light incidence surface. An optical recording disk 10 comprises a substrate 2, a recording layer 5, formed on the substrate, a light transmitting layer 7, formed on the recording layer, and a hard coat layer 8, formed on the light transmitting layer, and is characterized in that, when an operation of adhering an artificial fingerprint solution onto the optical recording disk's light incidence surface, onto which laser light is made incident, is performed and then an operation of wiping off the artificial fingerprint solution that has been adhered onto the light incidence surface is repeated five times, jitter becomes no more than 1.15 times that prior to the adhesion of the artificial fingerprint solution.

Abstract: An optical recording medium including a substrate and a light transmitting layer provided on the substrate so as to have a smaller thickness than that of the substrate, which is hardly warped and excellent in electrical characteristics and productivity, is provided. An optical recording medium includes: a substrate; and a light transmitting layer having a smaller thickness than that of the substrate. In this medium, a material of the substrate is a polyether imide resin.

Abstract: An optical recording medium includes a recording layer provided on a substrate. The recording layer includes first and second information layers and a spacer layer therebetween. The optical recording medium also includes a warpage adjusting layer provided on the side of the substrate opposite to the recording layer to reduce the warpage of the spacer layer caused by curing. A moisture proof layer is formed on the surface of the warpage adjusting layer opposite to the recording layer to reduce the warpage of the warpage adjusting layer caused by moisture absorption and releasing by the warpage adjusting layer.

Abstract: The present invention makes it possible to strip off a stamper stuck on a resin layer for groove formation during the manufacture of an optical disc from the resin layer without imparting damage or the like to the stamper. The present invention achieves this object by having the steps of bringing about a state in which the stamper protrudes from a substrate by a predetermined width, rotating the substrate with the back surface of the disc-shaped substrate attracted and held, elevating rollers capable of rolling relative to a contacting surface contacting with the protruding portion simultaneously with the rotation, and continuously applying a force working in a direction to separate the protruding portion from the substrate in the circumferential direction of the stamper.

Abstract: An optical information medium includes a disk-shaped substrate (100) having a center hole (101), an annular information recording area thereon, and an annular resin-based light-transmitting layer (102) thereon by which recording/reading laser beam is transmitted to the information recording area. The light-transmitting layer (102) terminates at a radially inner periphery which forms an annular raised rim (6). The rim is effective for protecting the light-transmitting layer from damages and dust adhesion, and when a plurality of such media are stacked, preventing the media from intimate contact.

Abstract: In an information recording medium according to the present invention, a recording layer is formed so as to be sandwiched by a first resin layer and a second resin layer, and a track pitch is in a range of 0.1 ?m to 0.5 ?m, inclusive, wherein at least one resin layer out of the first and second resin layers has a permeability according to JIS Z0208 in a range of 1 g/m2·24 h to 250 g/m2·24 h, inclusive.

Abstract: In an information recording medium according to the present invention, a recording layer, a first layer, and a second layer are formed so that a thermal conductivity of the first layer that contacts one surface of the recording layer and a thermal conductivity of the second layer that contacts another surface of the recording layer are both lower than a thermal conductivity of the recording layer and a track pitch is in a range of 0.1 ?m to 0.5 ?m, inclusive.

Abstract: An optical recording medium including a substrate and a light transmitting layer provided on the substrate so as to have a smaller thickness than that of the substrate, which is hardly warped and excellent in electrical characteristics and productivity, is provided. An optical recording medium includes: a substrate; and a light transmitting layer having a smaller thickness than that of the substrate. In this medium, a material of the substrate is an olefin maleimide copolymer.

Abstract: An optical recording medium includes a support substrate, a first resin layer and a second resin layer formed on opposite surface sides of the support substrate, an information recording layer formed between the first resin layer and the support substrate and containing a recording film, and a moisture-proof layer formed between the second resin layer and the support substrate and the moisture-proof layer contains at least one element among elements contained in the recording film.

Abstract: An optical recording medium includes a support substrate, a first resin layer and a second resin layer formed on opposite surface sides of the support substrate, an information recording layer formed between the first resin layer and the support substrate and containing a recording film, and a moisture-proof layer formed between the second resin layer and the support substrate and the moisture-proof layer contains at least one element among elements contained in the recording film.

Abstract: There are provided a composition for coating which can form an ink receiving layer having excellent adhesion with hydrophobic substrates, water-resistance and printing stability, and an optical recording medium having an ink receiving layer formed from this composition. The composition contains a radiation-curable compound (A) composed of 50 to 90% by weight of a monofunctional (meth) acrylic monomer and 10 to 50% by weight of a multifunctional (meth) acrylic monomer, a water-absorbing organic filler (C) in an amount of 10 to 60% by weight relative to (A), and a water-absorbing inorganic filler (D) in an amount of 1 to 20% by weight relative to (A). This composition is applied on a protecting film (6) and cured to form an ink receiving layer (7), to obtain an optical disk (1).