Abstract: An aromatic polyester composition which comprises 5 to 95 wt % of an ethylene naphthalenedicarboxylate copolymer and 95 to 5 wt % of an ethylene terephthalate (co)polymer and has a compatibility between these polymers of 0.15 to 0.5, and whose melting point lowers depending on the content of ethylene naphthalenedicarboxylate. This composition has excellent compatibility, transparency, barrier properties and heat resistance and is an excellent raw material for forming various molded products, particularly bottles. A bottle and its production process are also disclosed.

Abstract: Provided is a polyethylene naphthalenedicarboxylate resin composition having excellent transparency and hue, and containing a cobalt compound as a color-controlling agent, wherein the polyethylene naphthalenedicarboxylate resin composition comprises a polyethylene naphthalenedicarboxylate, an antimony compound, a cobalt compound and a phosphorous compound which is expressed by a specific structural formula and has an acid dissociation constant pKa of 1.0 or more, and the polyethylene naphthalenedicarboxylate resin composition is produced by using an antimony compound as a polycondensation catalyst.

Abstract: A circuit built-in light-receiving element includes a buried diffusion layer of the second conductivity type, a buried diffusion layer of the first conductivity type, an epitaxial layer of the second conductivity type, a diffusion layer of the first conductivity type, and a signal processing circuit element. The buried diffusion layer of the second conductivity type is formed in a first region on a substrate of the first conductivity type. The buried diffusion layer of the first conductivity type is selectively formed in the buried diffusion layer of the second conductivity type. The epitaxial layer of the second conductivity type is formed on the buried diffusion layer of the first conductivity type. The buried diffusion layer of the first conductivity type and the epitaxial layer of the second conductivity type constitute a light-receiving element.

Abstract: A loose tube for an optical fiber comprising a polybutylene terephthalate. The polybutylene terephthalate has a terminal carboxyl group concentration of 10 eq./10.sup.6 g.multidot.polymer or less and an intrinsic viscosity ?.eta.!, measured at 25.degree. C. in orthochlorophenol, of 0.9 to 1.4 dl/g.

Abstract: It is an object of the present invention to provide a photocoupler which maintains a high electric isolation performance and has an improved optical coupling efficiency without any variation of a conventional structure and a conventional production process. The photocoupler includes a light emitting device 1 and a photo detector 2 disposed in a facing relationship to each other, a silicon resin 4 covering over the light emitting device 1, a light transmitting resin 5 molding the silicon resin 4 which covers over the light emitting device 1 and the photo detector 2, and a light shielding resin 6 molding the light transmitting resin 5. In the photocoupler, a light scattering material is mixed in the silicon resin 4 which covers over the light emitting device 1. The amount of light scattering material mixed in the silicon resin 4 can be selected from 0.1 to 5.0 percentage by weight of the amount of the silicon resin 4.