Abstract: A construction in which a light emitting/receiving element and an optical fiber are optically coupled by a lens system formed by a biconvex aspherical lens. This lens is featured by: a first lens surface (R1) and a second lens surface (R2) both having a positive refracting power. At least one lens surface is formed by an aspherical surface. A distance L between the light emitting portion and the light receiving portion is 1.3129 mm<L<2.0129 mm. Lens thickness t at its center is 0.2147 mm<t<0.8822 mm; and 0.5<.vertline.f/.phi..vertline.<2.2632 where f=focal length of the lens, and .phi.=incident pupil diameter.

Abstract: The invention counterbalances the defects of optical glass and optical plastic so as to realize a high precision aspherical processing. The optical lens 1 includes a matrix 2 of optical glass and a coating of optical resin material applied to the surface of the matrix 2. A reflective wavefront of a lens plane 4 of the optical lens 1 is measured by means of a interferometer 5. The wavefront from the interferometer 5 is monitored by a computer system 7 to provide monitoring information. The lens plane 4 is irradiated or scanned with a short wavelength, ultraviolet laser beam L in accordance with the monitoring information, whereby the lens plane 4 is processed with the ultraviolet laser beam in non-contact manner into a shape to provide a most appropriate reflective wavefront.

Abstract: A pivotal support portion 2 protruding from a frame 1 is clamped between a pair of clamp ends 4 provided at the tip of an earpiece 3. A protrustons 7 formed in the inner surface of each of said pair of clamp ends 4 is fitted within a corresponding pivot hole 6 in each of the upper and bottom surface of said pivotal support portion 2. A lock mechanism 11 including protuberances 12 and recesses 13 is provided at a position where said clamp ends 4 are contacted with said frame 1. When said earpiece 3 is opened or enlarged to the maximum open position, said protuberances 12 become fitted within said respective recesses 13, so as to prevent said clamp ends 4 from separating in the outward direction.

Abstract: This invention provides a composition for coating plastics articles comprising (A) a hydrolyzed product of an organoalkoxysilane represented by the formulaR.sup.1.sub.n Si(OR.sup.2).sub.4-n (I)wherein R.sup.1 is a saturated or unsaturated hydrocarbon residue having 1 to 4 carbon atoms, R.sup.2 is a saturated hydrocarbon residue having 1 to 4 carbon atoms, and n is 0, 1 or 2, (B) an epoxy resin having an epoxy equivalent of about 120 to about 700, and (C) a bicyclic amidine represented by the formula ##STR1## wherein m is 3 or 5, or a salt thereof; a method of coating plastics articles with use of the composition; and plastics articles having a cured coating of the composition.