Abstract: A flexible circuit board including a flexible substrate having an insulating polyimide sheet and a wiring pattern portion formed in a mounting portion and a wiring pattern portion formed in a connecting portion, and a metal substrate on which only the mounting portion of the flexible substrate is secured by means of a thermoplastic polyimide film. Electronic devices are mounted on the mounting portion of the flexible substrate and heat generated by the electric devices can be effectively dissipated through the metal substrate. The connecting portion of the flexible substrate can be connected to an external circuit by means of a connector provided at an edge of the connecting portion. Since the connecting portion is not secured to the metal substrate, connector pins having a large mechanical strength can be used and the connecting portion can be bent at will.

Abstract: An optical recording medium comprising practically a naphthalocyanine dye represented by the following general formula (I): ##STR1## wherein M means a metal, metal oxide or metal halide, and --OR.sub.1, --OR.sub.2, --OR.sub.3 and --OR.sub.4 are the same or different and denote ether groups respectively having R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each of which is a saturated or unsaturated hydrocarbon group having 4-12 carbon atoms.

Abstract: Disclosed herein is a fabrication process of an optical recording medium permitting writing and reading-out of signals without any reflective layer. The medium is fabricated by coating, on a transparent thermoplastic resin substrate havnig pregrooves and pits or holes for preformatting signals, a dye solution of a phthalo/naphthalocyanine dye represented by the following general formula (I): ##STR1## wherein M means a metal, metal oxide or metal halide, and L.sub.1, L.sub.2, L.sub.3 and L.sub.4 mean individually a benzene or naphthalene ring skeleton which is unsubstituted or substituted by at least one monovalent substituent --Z selected from the class consisting of the following substituents: --R.sup.1, --OR.sup.2, --SiR.sup.3 R.sup.4 R.sup.5, --SR.sup.6, --COR.sup.7, --COOR.sup.8, --COHNR.sup.9, --NR.sup.10 R.sup.11, --R.sup.12 OR.sup.13, and --R.sup.14 X wherein R.sup.1 -R.sup.14 denote individually a hydrocarbon group having from 1 to 12 carbon atoms and X stands for a halogen atom.

Abstract: Disclosed herein is an optical recording medium permitting recording and reading-out of signals without any reflective layer. The optical recording medium comprises a transparent substrate and an optical recording layer provided directly on the substrate. The recording layer contains at least 80 wt. % of a naphthalocyanine dye represented by the following general formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be either the same or different and mean individually a straight-chain or branched alkyl group having 5-12 carbon atoms and M denotes a metal or a metal oxide or halide.

Abstract: Disclosed herein is an optical recording medium permitting recording and reading-out of signals without any reflective layer. The optical recording medium comprises a transparent substrate and an optical recording layer provided directly on the substrate. The recording layer contains at least 80 wt. % of a phthalo/naphthalocyanine dye represented by the following general formula (I): ##STR1## wherein L.sub.1, L.sub.2, L.sub.3 and L.sub.4 mean individually ##STR2## Q.sub.1, Q.sub.2, Q.sub.3, Q.sub.4, Q.sub.5, Q.sub.6, Q.sub.7, Q.sub.8, Q.sub.9 and Q.sub.10 denote individually a hydrogen atom or ##STR3## group; R.sub.1, R.sub.2 and R.sub.3 is individually a straight-chain or branched alkyl group having 1-12 carbon atoms, alkenyl group, phenyl group or substituted phenyl group, and two or more ##STR4## groups are contained on average in the molecule represented by the general formula (1); and M stands for a metal or a metal oxide or metal halide.

Abstract: An optical recording medium comprising practically a naphthalocyanine dye represented by the following general formula (I): ##STR1## wherein M means a metal, metal oxide or metal halide, and --OR.sub.1, --OR.sub.2, --OR.sub.3 and --OR.sub.4 are the same or different and denote ether groups respectively having R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each of which is a saturated or unsaturated hydrocarbon group having 4-12 carbon atoms.

Abstract: Disclosed herein is an optical recording medium which includes a recording layer composed of (a) an organometallic complex having an absorption maximum in the wavelength range of 600-1200 nm, (b) a resinous binder and (c) a sensitizer capable of generating radicals upon exposure to ultraviolet rays. The recording of information on the recording layer is effected with ease by exposure to ultraviolet rays. The reproduction of recorded information is effected by a laser beam having an oscillatory wavelength in the visible or near infrared wavelength range.

Abstract: A process for preparing alkyl nitroacetates by reacting an alkyl phenyl carbonate with a nitroparaffin in a polar aprotic solvent in the presence of a cyanide ion. The process permits a higher reaction rate, and thus the reaction can be completed even at room temperature.