LED having angled sides for increased side light extraction
First Claim
Patent Images
1. A light-emitting diode structure comprising:
- a multi-layer heterostructure, including a window portion and an active layer for generating light, said multi-layer heterostructure having a substantially flat surface for emitting light, said window portion being substantially transparent and having at least portions of one or more sides of said window portion at an oblique angle with respect to said substantially flat surface, wherein said oblique angle is selected to increase the amount of light escaping from said sides of said window portion and wherein a surface of said active layer has an area greater than an area of a surface of said window portion facing away from said active layer, wherein a thickness of said window portion is equal to or greater than 50 microns, and wherein said oblique angle is equal to or greater than 20 degrees, said oblique angle being measured as an angle between an outer surface of said one or more sides of said window portion and a direction normal to said substantially flat surface , wherein a primary light output service of said diode is other than a surface of said window portion.
3 Assignments
0 Petitions
Accused Products
Abstract
The invention is a method for designing semiconductor light emitting devices such that the side surfaces (surfaces not parallel to the epitaxial layers) are formed at preferred angles relative to vertical (normal to the plane of the light-emitting active layer) to improve light extraction efficiency and increase total light output efficiency. Device designs are chosen to improve efficiency without resorting to excessive active area-yield loss due to shaping. As such, these designs are suitable for low-cost, high-volume manufacturing of semiconductor light-emitting devices with improved characteristics.
118 Citations
47 Claims
-
1. A light-emitting diode structure comprising:
a multi-layer heterostructure, including a window portion and an active layer for generating light, said multi-layer heterostructure having a substantially flat surface for emitting light, said window portion being substantially transparent and having at least portions of one or more sides of said window portion at an oblique angle with respect to said substantially flat surface, wherein said oblique angle is selected to increase the amount of light escaping from said sides of said window portion and wherein a surface of said active layer has an area greater than an area of a surface of said window portion facing away from said active layer, wherein a thickness of said window portion is equal to or greater than 50 microns, and wherein said oblique angle is equal to or greater than 20 degrees, said oblique angle being measured as an angle between an outer surface of said one or more sides of said window portion and a direction normal to said substantially flat surface , wherein a primary light output service of said diode is other than a surface of said window portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
16. A light-emitting diode structure comprising:
a multi-layer heterostructure, including a window portion and an active layer for generating light, said multi-layer heterostructure having a substantially flat surface for emitting light, said window portion being substantially transparent and having at least portions of one or more sides of said window portion at an oblique angle with respect to said substantially flat surface and extending outward as said window portion approaches said active layer, wherein said oblique angle is selected to increase the amount of light escaping from said sides of said window portion, wherein a thickness of said window portion is equal to or greater than 50 microns, and wherein said oblique angle is equal to or greater than 20 degrees, said oblique angle being measured as an angle between an outer surface of said one or more sides of said window portion and a direction normal to said substantially flat surface, wherein a primary light output surface of said diode is other than a surface of said window portion. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
-
31. A light-emitting diode structure comprising:
-
a multi-layer heterostructure, including a window portion and an active layer for generating light, said multi-layer heterostructure having a substantially flat surface for emitting light, said window portion being substantially transparent and having at least portions of one or more sides of said window portion at an oblique angle with respect to said substantially flat surface, wherein said oblique angle is selected to increase the amount of light escaping from said sides of said window portion, wherein a thickness of said window portion is equal to or greater than 50 microns, and wherein said oblique angle is equal to or greater than 20 degrees, said oblique angle being measured as an angle between an outer surface of said one or more sides of said window portion and a direction normal to said substantially flat surface, and;
a reflector attached to another surface of said heterostructure, said other surface located opposite to and having an area smaller than said substantially flat surface for emitting light. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
-
Specification