Confocal

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confocal array of ellipses and hyperbolas

geometry

In geometry two conics are called confocal if they have the same focal points .

The set of all ellipses with the same focal points forms a family of ellipses in which no ellipses intersect. Likewise, no two hyperbolas with the same focal points intersect . In contrast, a hyperbola always intersects all confocal ellipses at right angles .

optics

In optics, two optical systems are called confocal if they have a common focal point .

These can be, for example, the illumination and observation beam paths of a confocal microscope or the concave end mirrors in a confocal laser resonator .

Lenses that are telecentric on both sides are made up of two confocally arranged lenses .

See also