Fast IR Fisheye Lens with Hyper-Hemispherical Field of View
J. Brian Caldwell
This month's patent design is a fisheye lens for long wavelength IR (8-12 μm wavelength range) that covers a full field of 270° at an astonishingly large aperture of f/0.7. This combination of field coverage and aperture is unprecedented, but in spite of the extreme specifications, the design is quite simple, consisting of only four germanium elements. The design would provide an interesting challenge to a manufacturer because the concave surface of the negative meniscus front element is hyper-hemispherical
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