Abstract: A light receiving structure for waveguide type optical devices, which excels in productivity, is compactly formed and permits highly efficient coupling, is provided. A recess is provided in part of the surface of a substrate on which an optical waveguide is formed, and a light-receiving element is mounted on the recess, with its light-receiving face upward. Near the recess is formed an end face of the optical waveguide in advance, so that a light be emitted therefrom. On the other hand, over the substrate is arranged a cover in which a groove is formed in a position opposite to the optical waveguide and a reflector is formed in a position opposite to the light-receiving element. The light emitted from the optical waveguide is reflected by the reflector and coupled to the light receiving element.

Abstract: A contour measuring apparatus and method of using the apparatus is disclosed to measure the three-dimensional contour of a surface. A multi-point light source directs a plurality of light beams onto the surface to be measured. The light beams are reflected through a lens onto a photodetector to produce electro-optically measurable optical images. A structure is provided to determine the local radius of curvature of the surface at each desired point of incidence of individual light beams and the three-dimensional surface contour of the surface being measured. A calibration device is provided to reduce instrument errors of the apparatus. The calibration device includes a calibration surface with a known contour to be positioned in substitution of the surface being measured.

Abstract: The present invention relates to a method and device for evaluating vision in humans. One feature of the present invention resides in a method and a device in which a plurality of symbols spaced from one another are moved and their speed of movement is adjusted so that the symbols become visible by a person to be evaluated as stationary symbols which appear in certain time intervals.At this point, an average statistic frequency of symbol appearance corresponds to the frequency of jumps of the person's eyes in direction of the symbols movement, while the value of the speed of the symbols movement at which they appear as stationary corresponds to an approximate speed of the person's eyes during the jumps.