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Abstract

A rounded square lens is used instead of a hemispherical lens in an LED package to produce a substantially Lambertian light emission pattern. A cross-sectional view of the rounded square lens cut along its diagonal forms a semicircular surface so as to emulate a hemispherical lens in areas close to the diagonal. A cross-sectional view of the lens cut along its width bisecting the lens forms a bullet shaped surface narrower than the semicircular surface but having the same height as the semicircular surface. The four corners of the lens are rounded. The surface of the lens smoothly transitions between the two surface shapes. Since the rounded square lens has a diagonal dimension larger than a maximum allowable diameter of a hemispherical lens in the same package body, a larger LED die may be used with the rounded square lens to output more light without increasing the size of the package while maintaining a Lambertian emission.

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First Claim