Abstract: An optical recording medium having two information sections (L0 and L1 layers) is provided by holding relationships: R1?R3+r R2?R4?r wherein R1, R2, R3, and R4 represent distances from the center of the medium at radial positions: R of an innermost circumferential track of a test area disposed on an inner circumferential side of the L1 layer; R of an outermost circumferential track of a test area disposed on an outer circumferential side of the L1 layer; R of an innermost circumferential guide groove of an information-recording area of the L0 layer; and R of an outermost circumferential guide groove of the information-recording area of the L0 layer respectively, and r represents a radius of a light beam on the L0 layer when the light beam is collected on the L1 layer.

Abstract: An optical recording medium including two recording layers, each containing an organic dye includes: a first disk substrate formed by laminating a first recording layer and a translucent intermediate layer sequentially on a first transparent substrate made of polycarbonate or the like; and a second disk substrate formed by laminating a reflective layer, a second recording layer, and an interface layer sequentially on a second substrate. The first and the second disk substrates are laminated with a transparent adhesive layer interposed therebetween in a manner that the translucent intermediate layer faces the interface layer. A reflectivity (R1) at a portion of a recording mark formed on any of the first and the second recording layers becomes higher than a reflectivity (R0) at a portion on the recording layer where the recording mark is not formed (R1>R0).

Abstract: An optical information-recording medium, which is provided with a substrate and a light-absorbing layer formed of a dye material on the substrate, includes a user information area in which a concave/convex pattern including spiral-shaped or concentric grooves are formed, and BCA which is provided on an inner circumferential side of the user information area and in which information is recorded with a bar code, wherein a concave/convex pattern, which is different from the concave/convex pattern in the user information area, is formed in BCA. With this construction, an optical information-recording medium, on which BCA information is reproduced without performing any tracking, is provided, wherein a BCA reproduced signal having a satisfactory signal quality is obtained from BCA.

Abstract: An optical recording medium which can precisely reproduce recording pits formed in pregrooves having width narrower than the diameter of a reproducing beam spot, and which can reduce the jitter and the block error rate, wherein the following unequal equation is satisfied: 0<b≦a<Dp≦Dg  (1) where Dg is a maximum depth of the pregrooves, Dp is a maximum depth of the prepits, a is a depth of edge parts between the pregrooves and the prepits on the inner peripheral side of the prepits, and b is a depth of the edge parts on the outer peripheral side of the prepits.

Abstract: An object of the present invention is to provide an optical recording medium that is excellent in recording and reading-out characteristics in the case of using a shortwave semiconductor laser and is good in light resistance and durability.

Abstract: An optical recording medium which can precisely produce recording pits formed in pregrooves having a width narrower than the diameter of a reproducing beam spot, and which can reduce the jitter and the block error rate, wherein the following unequal equation satisfied:

Abstract: A lubricating composition having an affinity for synthetic resins comprising a silicone oil and a fatty acid-modified silicone and a fatty acid ester. The lubricating coating composition is utilized in the preparation of a magnetic recording medium.

Abstract: A polycarbonate polyol having a main chain of the formula: ##STR1## wherein R is an aliphatic or alicyclic hydrocarbon group having 4 to 10 carbon atoms, and n is a number of 2.00 to 20.

Abstract: A polycarbonate polyol having a main chain of the formula: ##STR1## wherein R is an aliphatic or alicyclic hydrcarbon group having 4 to 10 carbon atoms, and n is a number of 2.00 to 20.