Abstract: In a lens barrel in which an imaging optical system can be retracted and protruded, a retaining member to retain an optical element nearest to the imaging element among the imaging optical system is provided, the optical element moves in a receding direction from the imaging element when the imaging optical system is protruded, and moves in an approaching direction to the imaging element when the imaging optical system is retracted by deforming the retaining member.

Abstract: It is to provide a wide-angle optical system for a solid image pickup device that favorably corrects distortion. The imaging lens is a biconvex lens, the object side face is formed into an aspheric shape in which the negative refracting power becomes stronger the farther the imaging lens is from an optical axis in the radial direction, and a condition expressed by the following expression (1) is to be satisfied; 0.8>|r1/r2|?0.5??(1) where, r1: center radius curvature of the object side face of the imaging lens r2: center radius curvature of the image surface side face of the imaging lens.

Abstract: A line producing system includes an input beam of radiant energy that enters a side of a low cost, radiant energy altering device. The radiant energy emerges from the light altering device radiating in a nearly 360 degree disc pattern forming a ring of ever expanding light.

Abstract: A lens for optical scanning condenses luminous flux deflected by an optical deflector to a plane to be scanned in a scanning image forming optical system. The lens is made of a plastic material by molding. A reference axis of an N-th order approximating curve of refractive index distribution ?n(x) of the lens is away from a center of a passing area, through which the luminous flux passes in the lens, by equal to or more than 10% of the width of the passing area.

Abstract: The invention provides an optical device including a polarization diversity unit for receiving an input optical signal and producing two beams of light having a same polarization state therefrom, a beam swapping element disposed for receiving the first and second beams of light and for redirecting the two beams of light to a same overlapping area of a modulator, and a reflective surface for reflecting the two beams of light back to the polarization diversity unit where they are combined to form an output optical signal. The beam swapping element is designed and positioned such that the first and second beams of light swap positions upon reflection from the reflective surface and trace out the other's optical path. Advantageously, this optical arrangement essentially eliminates all PDL and PMD.

Abstract: The method of using a tablet or coated tablet to introduce tint concentrate, UV absorbers, decolorant, conditioner and other optical chemistry into the dyebaths used for tinting plastic ophthalmic non-contact spectacle lenses and optical filters.

Abstract: Eyeglasses are modified to simulate ophthalmologic anomalies which may result from ophthalmic surgery. Various hazed eyeglass lenses are described.