Abstract: The organic positive temperature coefficient thermistor of the invention comprises a polyalkylene oxide, a water-insoluble organic compound and conductive particles having spiky protuberances, and so can operate at less than 100.degree. C. that is harmless to the human body, with low initial resistance in a non-operating state (at room temperature), and a large rate of resistance change upon transition from the non-operating state to an operating state, and improved humidity resistance.

Abstract: An organic positive temperature coefficient thermistor contains polyethylene oxide where Mw>2,000,000 and conductive particles each having spiky protuberances. Preferably, the thermistor is prepared by blending the polyethylene oxide with the conductive particles interconnected in a chain form. The thermistor is operated at a temperature of 60 to 70.degree. C. little harmful to the human body, and has low initial resistance in its non-operating state (at room temperature), a large rate of resistance change upon transition from its non-operating state to operating state, a sharp resistance rise upon operation, and stable performance even upon repetitive operation.

Abstract: An organic positive temperature coefficient thermistor comprises a thermoplastic polymer matrix, a low-molecular organic compound, and conductive particles, each having spiky protuberances thereon. The low-molecular organic compound has a melting point of 40.degree. C. to 100.degree. C. The conductive particles are interconnected in a chain form.

Abstract: A phase change type optical recording medium has a recording layer of a recording material containing elements A, B, and C wherein A is Ag and/or Au, B is Sb and/or Bi, and C is Te and/or Se. Information is recorded by directing a light beam to the recording layer to form recorded marks therein such that the recorded marks are amorphous or microcrystalline while an unrecorded portion of the recording layer remains crystalline, and the A concentration of the unrecorded portion is at least 0.5 atom % higher than the A concentration of the recorded marks. C/N and modulation factor are improved and such improvements are kept even after hot humid storage.

Abstract: In a phase change type of optical recording medium including on a substrate a lower dielectric layer, a recording layer, a first upper dielectric layer contiguous to said recording layer, a second upper dielectric layer and a reflective layer, the recording layer comprises a recording material containing an element A that represents silver and/or gold, an element B that represents antimony and/or bismuth, an element C that represents tellurium and/or selenium, an element indium, and an element M that represents at least one element selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, manganese, tungsten and molybdenum, with the atomic ratio of the elements in said recording material having the following formula:{(A.sub.a B.sub.b C.sub.1-a-b).sub.x (In.sub.0.5 C.sub.0.5).sub.y B.sub.1-x-y }.sub.1-z M.sub.zwherein 0.10.ltoreq.a.ltoreq.0.40, 0.10.ltoreq.b.ltoreq.0.40, 0.20.ltoreq.x.ltoreq.0.80, 0.01.ltoreq.y.ltoreq.0.60, and 0.001.ltoreq.z.ltoreq.0.20.

Abstract: An optical recording medium has a mask layer 4, an intermediate dielectric layer 5, a recording layer 6, and a reflective layer 8 on a transparent substrate 2. The recording layer 6 contains a recording material which changes its crystallographic structure upon exposure to recording light for recording information. The mask layer 4 contains a mask material which increases its light transmittance when melted and has a complex refractive index (n.sub.0 -ik.sub.0), of which the real part n.sub.0 drops by 1.0 or less and the imaginary part k.sub.0 drops by 0.25-1.0 when the mask material converts from a crystalline state to an amorphous or microcrystalline state. Signals can be reproduced from the medium with high C/N without resorting to reading light of shorter wavelength or an optical pickup objective lens having a larger numerical aperture and even when the linear velocity of the medium relative to recording and reproducing light is low.

Abstract: In an optical recording medium comprising a recording layer on a substrate, the recording layer contains a recording material which consists essentially of A, B, C, MI, and MII wherein A is Ag and/or Au, B is In, C is Te and/or Se, MI is Sb and/or Bi, and MII is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mn, W and Mo, the atomic ratio of the respective elements being represented by the formula:[(A.sub.a B.sub.b C.sub.1-a-b).sub.x MI.sub.1-x ].sub.1-y MII.sub.ywherein 0.01.ltoreq.a<0.50, 0.01.ltoreq.b<0.50, 0.30.ltoreq.x.ltoreq.0.70, and 0.001.ltoreq.y.ltoreq.0.20. Information is recorded and erased by exposing the recording layer to a light beam for causing the recording layer to change its crystallographic state. The invention improves C/N and repetitive recording performance at a low linear velocity of the recording layer relative to the light beam and enables reproduction in accordance with the CD standard.

Abstract: An optical recording medium includes a recording layer which contains as major components an element (A) selected from Ag, Au, Cu and Pt, an element (B) selected from Ti, Zr, Hf, V, Nb, Ta, Mn, W and Mo, and an element (C) selected from Te, Se and S. The medium features high performance and versatile use.