Light-emitting diode with diagonal faces
AssigneeHewlett-Packard Company
InventorRoland H. Haitz
Life of this patent
Estimating the term…
Abstract
A transparent light-emitting diode has front and back parallel faces and a plurality of side faces perpendicular to the back face. Diagonal faces interconnect each side face with the front face to form a truncated polygonal pyramid surmounting a polygonal base of the light-emitting diode. Because some of the light impinges on the diagonal faces at an angle less than the critical angle for total internal reflection, from 1.5 to 2 times as much light is extracted from the LED as a conventional rectangular LED without the diagonal faces. The diagonal faces on the LEDs are readily made by sawing V-shaped grooves in the front face of a wafer on which the LEDs are fabricated.
Claims17
A transparent light-emitting diode comprising:
- an opaque back face at a back of the light-emitting diode;
- a front electrical contact at the front of the light-emitting diode;
- and
- a body of transparent semiconductor between the back and the front electrical contact having a back p-n junction substantially parallel and adjacent to the back face and remote from the front electrical contact, the body being in the form of a polygonal base adjacent to the back and having side faces perpendicular to the back p-n junction, the body also being surmounted by a truncated polygonal pyramid through the side faces of which light is emitted from the light-emitting diode, each face of the pyramid intersecting a face of the base along a line, the front electrical contact being in the truncated end of the pyramid.
A transparent light-emitting diode comprising:
- a body of semiconductor material having;
- a back face,
- a front face parallel to the back face,
- a plurality of side faces extending away from and perpendicular to the back face,
- a plurality of diagonal faces interconnecting the side faces and the front face, the number of diagonal faces being the same as the number of side faces;
- means for making electrical contact with the front face;
- means for making electrical contact with the back face;
- and
- a p-n junction within a portion of the body having side faces between the back face and the intersection of the diagonal faces and the side faces for emitting light.
Dependencies are inferred from the claim text.