LED package with a rounded square lens

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.

Description

technical field

[0001] The present invention relates to light emitting diode (LED) packages, and more particularly, to LED packages with rounded square lenses emitting a substantially Lambertian emission pattern. Background technique

[0002] Prior Art Figure 1 is a top perspective view of an LED package 10 copied from the present assignee's US Design Patent No. D 598871, which is incorporated herein by reference. The trade name for this package is Rebel TM . Package 10 is approximately 3mm on each side. Package 10 contains a square LED die whose sides are aligned with the sides of package 10 . The central axis of the LED die is along the central axis of the hemispherical lens 12 . Anode and cathode electrodes are on the bottom surface of the package 10 for soldering to metal pads on the printed circuit board. The anode and cathode electrodes formed on the semiconductor layer of the LED are electrically connected to the anode and cathode electrodes on the bottom of the ...

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