Electro-optical sensor for marks on a sheet
First Claim
1. An optical sensor which comprises a board extending laterally over a path along which is moveable a sheet containing marks in selected areas in adjacent columns which extend longitudinally of the sheet, an array of a plurality of light sources and photodetectors each including a separate light source and photodetector which are mounted on said board, the separate light sources and photodetectors being spaced laterally and offset longitudinally from each other to provide said array, a rod defining a cylindrical lens mounted on said board and extending laterally along said board to define a plurality of discrete, laterally spaced zones coincident with said areas of said columns in which zones illumination from said sources is focused and from which zones illumination is focused on said detectors.
15 Assignments
0 Petitions
Accused Products
Abstract
An electro-optical sensor senses marks on a sheet which travels longitudinally with respect to a printed circuit board, carrying linear arrays of light sources (LEDs) and photodetectors and optics which define zones displaced laterally across the width of a sheet of paper, longitudinal columns of which can contain marks, the presence and absence of which marks is detected by the sensor. The sensor is especially adapted for use in detecting marks which indicate votes on paper ballots in electronic, computerized vote counting apparatus.
-
Citations
12 Claims
- 1. An optical sensor which comprises a board extending laterally over a path along which is moveable a sheet containing marks in selected areas in adjacent columns which extend longitudinally of the sheet, an array of a plurality of light sources and photodetectors each including a separate light source and photodetector which are mounted on said board, the separate light sources and photodetectors being spaced laterally and offset longitudinally from each other to provide said array, a rod defining a cylindrical lens mounted on said board and extending laterally along said board to define a plurality of discrete, laterally spaced zones coincident with said areas of said columns in which zones illumination from said sources is focused and from which zones illumination is focused on said detectors.
Specification