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 optical element comprises an optical polymer, and wherein the first aspheric optical surface is a convex object-side surface characterized by a second diameter and the second aspheric optical surface is a concave image-side surface characterized by a third diameter;
• and
• 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 convex image-side surface characterized by a fifth diameter;
• wherein the array of monochromatic light sources, first and second 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 and fifth diameters divided by a sum of first separation, first thickness, second separation and second thickness, the aspect ratio having a value of at least 0.77, and an exit aperture wherein the chief ray of each light source substantially converges, the exit aperture having a sixth diameter and being separated from the fourth aspheric optical surface by a third 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 and second optical elements.