What is the difference between a Double-Sided Telecentric lens and a standard Telecentric Lens?
Double-Sided Telecentric lenses provide both image and object side telecentricity. With the single telecentric lens, the rays at the image plane are still coming in at strong angles. If we “double up” on the lenses, we now have telecentric performance front and back. The resulting system is less prone to optical aberrations and geometrical distortions. Image size will not vary across the field due to positioning of the sensor. Modern sensor pixels are both getting smaller and more cluttered up with electronic circuitry. As light collection is normally a function of active area, manufacturers are adding micro lenses over each pixel to aid in the collection of light. These micro lenses are most effective when the incoming rays are 5 degrees, or less, off normal. The telecentric cone of light is a major benefit in these situations.
