A position determining system for providing electrical signals representative of the positions of a light source movable within a defined area. The system may be implemented for purposes of data entry or for purposes of object location or surveying. When embodied in a data entry tablet, the invention provides signals representative of the positions of a stylus movable within the area of the tablet and comprising first and second photodetectors spaced along a base line by a predetermined distance, and means associated with each photodetector and operative to provide a movable narrow field of view for each photodetector. Means are provided for monitoring the angular position of each of the fields of view with respect to the base line and for providing a signal indication of the respective angular positions. A stylus having a light emitter at the tip thereof is movable within the area of the tablet and provides light detachable by each of the photodetectors. Each of the photodetectors provides a respective signal when the field of view of the corresponding photodetector receives light from the emitter. Means are provided which are operative in response to the signal indication of the angular position of each of the movable means at which light from the emitter is respectively detected to provide a signal representing the position of the emitter within the area of the tablet.

Electro-optical position determining system

An active auto focus system in which a beam of modulated energy is projected towards a subject to be focussed upon with the energy reflected therefrom directed towards a detector array. The detector array comprises a number of radiation responsive elements arranged in parallel rows and in a pattern which permits the reflected energy to impinge upon at least one detector in each of the rows simultaneously. The arrangement allows a digital type output indicative of the position of the reflected energy on the array and thus the position of the subject from the camera.

Digital auto focus system utilizing a photodetector array

Active auto focus system improvement

An electromagnetic radiation intensity comparator is disclosed for providing an indication of differences between electromagnetic radiation intensities occurring at different photodetectors.

Electromagnetic radiation intensity comparator apparatus

An electro-optic sampler comprises a body of semiconductor material that can be energized to emit polarized light, a photodetector device for generating an electrical output signal representative of the intensity with which light polarized in a predetermined manner is incident on the photodetector device, and a body of electro-optic material defining an optical waveguide for transmitting light from the source of polarized light to the photodetector. First and second electrodes are provided for establishing an electrical field within the body of electro-optic material. The body of electro-optic material has a spherical index ellipsoid when the first and second electrodes are at the same potential and otherwise has a non-spherical index ellipsoid.

Electro-optic sampler

This invention relates to automatic range finder circuitry for cooperative utilization with apparatus, such as a photographic camera or the like, using triangulation for range distance measurement, and having an automatic range finder mechanism. The apparatus is arranged to sweep a collimated light beam across a plane which includes a subject of interest, and the reflected light returning to the apparatus is imaged on spaced photoelectric transducers differentially connected to produce a varying electrical signal. The range finder mechanism includes a cam adapted to move as a function of the sweeping light beam. When the reflected light falls equally on the photoelectric transducers the range distance has been established. The present invention supports this apparatus by providing circuitry for detecting the instant that the reflected illumination on the photoelectric transducers is equal, and for providing an output signal which is used to lock the cam against further displacement. The range distance intelligence, defined by the locked cam position, can then be utilized for any convenient purpose.

J Frazee

Papers

Automatic rangefinder electronic circuitry