Low profile and high efficiency lighting device for backlighting applications
First Claim
1. A light source comprising:
- a flexible substrate having a dielectric layer sandwiched between top and bottom metal layers, said flexible substrate being divided into first and second regions; and
a plurality of dies bonded to said bottom layer in said first region, each die comprising a semiconductor light emitting device that emits light, said first region being characterized by a normal to said bottom layer in said first region, at least one of said top and bottom metal layers comprising a plurality of electrical traces for connecting said dies to circuitry that is external to said light source;
wherein said top metal layer of said substrate is reflective in said second region, said substrate being bent such that said first region is at an angle with respect to said second region and a portion of said light emitted from said dies at an initial angle greater than zero to said normal striking said second region and being reflected therefrom into a direction having an angle with respect to said normal that is less than said initial angle.
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Accused Products
Abstract
A light source having a flexible substrate and a plurality of dies having LEDs is disclosed. The light source can be conveniently utilized to provide an extended light source by bonding the light source to a suitable light pipe. The substrate is divided into first and second regions. The dies are bonded to the substrate in a first region. A portion of the surface of the substrate in the second region is reflective. The substrate is bent such that the second region forms a reflector that reflects light that would otherwise be emitted in a non-useful direction to a more useful direction. The substrate can be constructed from a three layer flexible circuit carrier in which the dies are mounted on a bottom metal layer to provide an improved thermal path for heat generated in the dies.
28 Citations
10 Claims
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1. A light source comprising:
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a flexible substrate having a dielectric layer sandwiched between top and bottom metal layers, said flexible substrate being divided into first and second regions; and a plurality of dies bonded to said bottom layer in said first region, each die comprising a semiconductor light emitting device that emits light, said first region being characterized by a normal to said bottom layer in said first region, at least one of said top and bottom metal layers comprising a plurality of electrical traces for connecting said dies to circuitry that is external to said light source; wherein said top metal layer of said substrate is reflective in said second region, said substrate being bent such that said first region is at an angle with respect to said second region and a portion of said light emitted from said dies at an initial angle greater than zero to said normal striking said second region and being reflected therefrom into a direction having an angle with respect to said normal that is less than said initial angle. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An extended light source comprising:
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a light source comprising a flexible substrate divided into a die mounting region and first and second attachment regions; and a plurality of dies bonded to said substrate in said die mounting region, each die comprising a semiconductor light emitting device that emits light; and a light pipe comprising a sheet of transparent material having top and bottom surfaces and a first edge surface, said light source being attached to said sheet such that a portion of said first attachment region is bonded to said top surface and a portion of said second attachment region is bonded to said bottom surface, said die attachment region being positioned opposite to said first edge such that light from said dies enters said sheet through said first edge. - View Dependent Claims (8, 9, 10)
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Specification