Uniform intensity illumination system

Claim 1

IN A READING STATION FOR A PHOTO-ELECTRIC READER WHEREIN DATA MARKS ARE ARRANGED IN SELECTED ONES OF A PLURALITY OF PREDETERMINED LOCATIONS ON A SUPPORT AND READ IN POTENTIALLY EQUAL GROUPS OF LINEAR ARRAYS, INCLUDING APPARATUS FOR PROVIDING A ZONE OF LIGHT HAVING A LENGTH AND A WIDTH SUBSTANTIALLY EQUAL TO THE DIMENSIONS OF EACH OF SAID POTENTIALLY EQUAL LINEAR ARRAYS, SAID APPARATUS INCLUDING A DISK-LIKE SOLID FORMED OF LIGHT TRANSMITTING MATERIAL, SAID SOLID HAVING A PAIR OF PLANES, SAID PLANES BEING BOUNDED BY A FIRST SURFACE DEFINING A PORTION OF A PARABOLIC CURVE AND A SECOND SURFACE PARALLEL TO THE DIRECTRIX OF SAID CURVE, A LIGHT REFLECTING COATING ON AT LEAST A PORTION OF SAID FIRST SURFACE, AN APERTURE FORMED IN SAID STRUCTURE AT THE FOCUS OF SAID CURVE, A LIGHT RESPONSIVE ELEMENT FOR EACH POSSIBLE UNIT POSITION IN SAID LINEAR ARRAY; THE IMPROVEMENT COMPRISING: A STRUCTTURE INCLUDING A PLURALITY OF CHANNELS LOCATED BETWEEN EACH OF SAID LIGHT RESPONSIVE ELEMENTS AND SAID SECOND SURFACE, SAID CHANNELS BEING SUBSTANTIALLY ORTHOGONAL TO SAID SECOND SURFACE, THE INTERIOR OF THE WALLS OF SAID CHANNELS BEING NON-REFLECTIVE, THE CROSS-SECTIONAL AREA OF EACH OF SAID CHANNELS BEING LESS THAN OR EQUAL TO THE CROSS-SECTIONAL AREA OF SAID DATA MARKS, THE CROSS-SECTIONAL AREA OF SAID CHANNELS INCREASING IN THE DIRECTIONS OF THE EXTREMITIES OF SAID SECOND SURFACE WHEREBY TO IMPROVE UNIFORMITY OF THE INTENSITY OF LIGHT TRANSMITTED.