Illumination assembly for 3D data acquisition

An illumination assembly operable to generate a patterned illumination that maintains high contrast over a wide temperature range, the illumination assembly comprising:

• an array of monochromatic light sources positioned on an illumination plane, wherein each monochromatic light source is characterized by a numerical aperture and a chief ray and the illumination plane is characterized by a first diameter;
• a first optical element having a first aspheric optical surface separated from the array of monochromatic light sources by a first separation and the first optical element having a second aspheric optical surface juxtaposed from the first aspheric optical surface by a first thickness, wherein the first aspheric optical surface is a center-concave and convex object-side surface characterized by a second diameter and the second aspheric optical surface is a convex image-side surface characterized by a third diameter;
• a second optical element having a third aspheric optical surface separated from the second aspheric optical surface by a second separation and the second optical element having a fourth aspheric optical surface juxtaposed from the third aspheric optical surface by a second thickness, wherein the third aspheric optical surface is a convex object-side surface characterized by a fourth diameter and the fourth aspheric optical surface is a concave image-side surface characterized by a fifth diameter;
• and
• a third optical element having a spheric optical surface separated from the fourth aspheric optical surface by a third separation and the third optical element having a planar optical surface juxtaposed from the spheric optical surface by a third thickness, wherein the spheric optical surface is a convex object-side surface characterized by a sixth diameter and the planar optical surface is characterized by the sixth diameter;
• wherein the array of monochromatic light sources, first, second, and third optical elements define an optical axis substantially parallel to the chief ray of each light source, an on-axis focal length, an aspect ratio defined as a largest of first, second, third, fourth, fifth, and sixth diameters divided by a sum of first separation, first thickness, second separation, second thickness, third separation, and third thickness, the aspect ratio having a value of at least 0.68, and an exit aperture wherein the chief ray of each light source substantially converges, the exit aperture having a seventh diameter and being separated from the planar optical surface by a fourth separation;
• and
• wherein the on-axis focal length is a focal length of light rays which propagate along the optical axis and which pass through the first, second and third optical elements.