摘要:
The invention provides an optical disc comprising a circular glass substrate (2) having information-carrying means (3) on one major surface. A protective member (4) of a resin includes a circular flat portion (42) and an annular rim (41) extending perpendicular from the periphery of the flat portion (42). The glass substrate (2) is integrally joined to the protective member (4) such that the information-carrying means (3) of the glass substrate (2) may face the covering portion (42) of the protective member (4). The outer side of the glass substrate (2) is surrounded by the protective member rim (41) to leave a shock absorbing space therebetween. The invention prevents the glass substrate from failure at its corner when impact is applied to the disc.
摘要:
A magneto-optical disc comprising a recording layer and a protective coating on a substrate is operated for magneto-optical recording in a magnetic field modulation mode such that the protective coating is in sliding contact with a magnetic head. The protective coating is obtained by curing with radiation a polymerizable composition which contains a fatty acid ester and radiation-curable compounds including a monofunctional (meth)acrylic monomer, a polyfunctional (meth)acrylic monomer, and optionally, an acrylic oligomer.
摘要:
An optical disc is constructed by joining a pair of resin substrates through an adhesive layer so that information carrying means is disposed inside. The resin substrate has a diameter-to-thickness ratio d/t.gtoreq.180. The adhesive layer has a Young's modulus of 0.1-1 kgf/mm.sup.2 at 20.degree. C. and a mechanical dissipation factor (tan.delta.) of 0.6-5.0 at 20.degree. C. The adhesive layer is formed of a hot melt adhesive, pressure-sensitive adhesive, room temperature curable adhesive or ultraviolet curable adhesive. The disc is resistant to both heat and vibration.
摘要:
A magneto-optical recording disc adapted for magneto-optical recording in the magnetic field modulation system by means of a magnetic head in continuous contact with the disc includes a recording layer on a substrate and a wear resistant resinous coating thereon. The coating is formed of a resin containing carbon particles having a mean particle size of 1 to 15 .mu.m. The magnetic head is in sliding contact with the surface of the coating during operation. The coating is effective for reducing friction with the magnetic head and retains such reduced friction over a long time.
摘要:
A magneto-optical disc includes a recording layer (4) and a protective film (7) of radiation-cured resin on a substrate (2). Information is written in the recording layer with the aid of a magnetic head in sliding contact with the disc. In a first form, when the protective film is subject to a micro-vibration scratch test by setting the disc in a thin film scratch tester equipped with a diamond indentor having a radius of curvature R of up to 50 .mu.m, the relationship: 0.8.ltoreq.L/R.sup.2 .ltoreq.2.7 is met wherein L is the critical load (N.m) under which the thin film is scratched. In a second form, the protective film has a dynamic modulus of 5.0.times.10.sup.9 to 4.0.times.10.sup.10 dyn/cm.sup.2 at 100.degree. C. The disc is highly durable.
摘要翻译:磁光盘包括在基板(2)上的记录层(4)和辐射固化树脂的保护膜(7)。 借助于与盘滑动接触的磁头将信息写入记录层。 在第一种形式中,当通过将该盘设置在具有曲率半径R至多为50μm的金刚石压痕器的薄膜划痕试验机中进行微振动划痕试验时,保护膜的关系为:0.8 满足 = L / R2 = 2.7,其中L是薄膜被划伤的临界负载(Nm)。 在第二种形式中,保护膜在100℃时的动态模量为5.0×10 9至4.0×10 10 dyn / cm 2。该盘是高度耐用的。
摘要:
A protective coating made of resin, preferably a radiation curable resin containing fluoroplastic fine particles having a low surface energy is provided in the form of the uppermost layer facing a magnetic head, thereby improving the frictional properties and durability of a magneto-optical disc that is used with a magnetic field modulation system in which the magnetic head comes in constant contact therewith.
摘要:
A mechanical property such as axial acceleration of an injection molded resin disc substrate or an optical disc comprising the same is determined by measuring a variation in radius or diameter of the substrate or disc in its circumferential direction, and determining the mechanical property of the substrate or disc from the measurement.
摘要:
A magneto-optical disc includes a substrate, a recording layer, and a protective coating comprised of a resin and a lubricant. The disc is operated for magneto-optical recording in a magnetic field modulation mode such that the protective coating is in sliding contact with a magnetic head. The lubricant is a higher fatty acid ester R.sup.1 --COO--R.sup.2 wherein R.sup.1 is a saturated or unsaturated aliphatic C.sub.10 -C.sub.30 hydrocarbon residue, and R.sup.2 is a saturated or unsaturated aliphatic C.sub.10 -C.sub.30 hydrocarbon residue. Alternatively, the protective coating is formed by curing with radiation a composition containing a lubricant and a radiation-curable compound such that micropores are locally formed in or near the outer surface of the protective coating, the lubricant being distributed in the micropores. In either case, the protective coating is effective for minimizing friction with the magnetic head.
摘要:
An optical recording medium includes a substrate, a first recording layer formed on the substrate and containing an element selected from the group consisting of Si, Ge, C, Sn, Zn and Cu as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Al as a primary component, the optical recording medium being constituted to be irradiated by a laser beam projected onto the side opposite from the substrate and the total thickness of the first recording layer and the second recording layer being equal to or thinner than 40 nm. According to the thus constituted optical recording medium, it is possible to decrease a noise level and improve a C/N ratio in a reproduced signal.
摘要:
An optical recording medium includes a substrate, a first recording layer formed on the substrate and containing an element selected from the group consisting of Si, Sn and Ge as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Ag as a primary component, the optical recording medium being constituted to be irradiated by a laser beam projected onto the side opposite from the substrate. According to the thus constituted optical recording medium, it is possible to decrease a noise level and improve a C/N ratio in a reproduced signal.