Abstract: The present invention is to provide an optical recording medium which is capable of performing good recording and reproducing by using a laser having a wavelength of 300 to 900 nm, a novel azo metal chelate compound, and a novel azo compound. Furthermore, the present invention is to provide an optical recording medium having an azo metal chelate compound in a recording layer.

Abstract: An optical filter of the present invention contains at least one tetra-acenaphthoporphyrin compound. The tetra-acenaphthoporphyrin compound has preferably its absorption maximum in a wavelength range of from 530 to 570 nm and a ratio of an absorption coefficient at 550 nm to an absorption coefficient at 525 nm of not less than 1.2. Also, a percentage of light transmittance at 550 nm to light transmittance at 525 nm is preferably not more than 85%. According to the present invention, it is possible to provide the optical filter which can eliminate an unnecessary light mainly existing in a wavelength of from 520 to 700 nm and is excellent in durability. A display unit using the optical filter of the present invention can improve contrast in a bright place, and improve color purity of luminescent color.

Abstract: Aqueous ink which contains compounds having one or more structures represented by general formula (1) in a molecule or salts thereof and which has a clear hue and is excellent in light fastness and moisture resistance is provided.

Abstract: This invention provides sulfur-containing (meth)acrylic ester compounds each of which is represented by the following formula (1); wherein R1 and R2 each independently represent a hydrogen atom or an alkyl group or may be fused together to form a ring, R3 represents a hydrogen atom or a methyl group, X1 represents an oxygen atom or a sulfur atom, m stands for an integer of from 0 to 3, and n stands for an integer of from 1 to 4, polymerizable compositions comprising the sulfur-containing (meth)acrylic acids, and cured products and optical parts obtained by polymerizing the polymerizable compositions. The sulfur-containing (meth)acrylic ester compounds according to the present invention are very useful, as monomers for photocurable, polymerizable compositions, in applications such as optical materials and dental materials.

Abstract: A sulfur-containing unsaturated carboxylate compound comprising a sulfur-containing substituent and at least two &agr;,&bgr;-unsaturated carboxylic acid residues, which are each attached to a secondary or tertiary carbon atom via an oxygen atom; a polymerizable composition comprising the sulfur-containing unsaturated carboxylate compound; a cured product prepared by polymerizing the polymerizable composition; an optical component consisting of the cured product; and novel intermediate compounds for preparation of the above carboxylate.

Abstract: A sulfur-containing (thio)ether (co)polymer comprising repetitive structural units represented by general formulas 1 and 2, and an optical element using the (co)polymer: where A and B are bivalent organic group; R1 and R2 are hydrogen or alkyl; X1 to X4 are oxygen or sulfur; Y1 and Y2 are halogen, hydroxy, —OR3 or —SR4, in which R3 is sulfur-containing alkyl, aryl, heterocycle or acyl optionally having a substituent other than SH; and R4 is alkyl, aryl, heterocycle or acyl; provided that —OR3 and/or —SR4 constitute 10 to 100% of the total of Y1+Y2. The (co)polymer exhibits good optical, mechanical and thermal properties and a higher refractive index, and may be prepared in a good productivity. The sulfur-containing (thio)ether (co)polymer is useful for manufacturing a variety of optical elements.

Abstract: A low-birefringent organic optical component comprising a polymer prepared by polymerizing a racemic mixture of the monomer with an asymmetric spiro ring represented by general formula (1) as an essential ingredient; wherein ring A represents a monocyclic or polycyclic organic group, wherein two ring As are mutually bound each other via a spiro bond to form a spiro ring which has a molecular asymmetric structure; n is an integer of 0 to 10; X.sub.1 and Y.sub.1 are binding groups; and Z.sub.1 is a polymerization-active group. The component has excellent transparency, mechanical strength and heat resistance, as well as a low birefringence.

Abstract: A polycarbonate copolymer comprising the repeating structural unit represented by general formula (1-a) and at least one of the repeating structural units represented by general formulas (2-a) and (3-a) is provided.