SOLID STATE LAMP ASSEMBLY
First Claim
1. A solid state lamp comprising a substantially flat lightemitting diode element having a top surface and a bottom surface, said diode element containing means for producing light internally thereof directed upwardly toward said top surface and downwardly toward said bottom surface, mounting means to which said element is attached at said bottom surface thereof for supporting said element and for making an electrical connection therewith, and electrical contact means at a relatively small area of said top surface, said top surface being substantially unobstructed optically to the emission of light upwardly therefrom, wherein the improvement comprises means for providing said supporting and electrical attachment to only a portion of said bottom surface of the light-emitting element whereby a major portion of said bottom surface is bounded by air or other low optical refractive index material thereby minimizing the optical critical angle at said bottom surface and maximizing the internal reflection of said internally produced light at said bottom surface thereby increasing the amount of light emitted upwardly from said top surface of the diode element.
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Accused Products
Abstract
A light-emitting diode element is mounted on a supporting tab, in a depression thereof having polished tapered sides. A dimple is provided in the depression, at the underside of the diode, so that only a small area of the bottom surface of the diode is in contact with the tab, thereby maximizing internal light reflection at the bottom surface and thus increasing the amount of light usefully emitted through the top and sides of the diode. The polished tapered sides of the depression in the tab reflect upwardly the light emitted through the sides of the diode, so as to be useful along with light emitted through the top of the diode. The assembly is encapsulated in glass or plastic.
282 Citations
8 Claims
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1. A solid state lamp comprising a substantially flat lightemitting diode element having a top surface and a bottom surface, said diode element containing means for producing light internally thereof directed upwardly toward said top surface and downwardly toward said bottom surface, mounting means to which said element is attached at said bottom surface thereof for supporting said element and for making an electrical connection therewith, and electrical contact means at a relatively small area of said top surface, said top surface being substantially unobstructed optically to the emission of light upwardly therefrom, wherein the improvement comprises means for providing said supporting and electrical attachment to only a portion of said bottom surface of the light-emitting element whereby a major portion of said bottom surface is bounded by air or other low optical refractive index material thereby minimizing the optical critical angle at said bottom surface and maximizing the internal reflection of said internally produced light at said bottom surface thereby increasing the amount of light emitted upwardly from said top surface of the diode element.
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2. A lamp as claimed in claim 1, in which said mounting means is provided with a concave dimple on the surface thereof, said light-emitting element being positioned over at least a portion of said dimple and attached at the edge of the bottom surface thereof to said mounting means, whereby said dimple defines a space bounding a substantial area of said bottom surface of the diode.
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3. A lamp as claimed in claim 2, in which said light-emitting element is substantially square, and in which said dimple is circular and has a diameter less than the diagonal of said light-emitting element, said light-emitting element being attached only near the corners thereof to said mounting means.
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4. A solid state lamp comprising a light-emitting diode element having a top surface and a bottom surface, wherein the improvement comprises a substantially flat suPporting tab of electrically conductive material provided with a depression having a bottom surface and having reflective tapered sides tapering mutually inwardly toward said bottom surface, and means mounting said light-emitting element to said supporting tab in said depression thereof with only a portion of said bottom surface of the diode element being in contact with said bottom surface of the depression, whereby a major portion of said bottom surface of the diode is bounded by air or other low optical refractive index material thereby minimizing the optical critical angle at said bottom surface of the diode element.
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5. A lamp as claimed in claim 4, in which said bottom surface of the depression is provided with a concave dimple, said light-emitting element being positioned over at least a portion of said dimple and attached at the edge of the bottom surface thereof to said bottom surface of the depression, whereby said dimple defines a space bounding a substantial area of said bottom surface of the diode.
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6. A lamp as claimed in claim 5, in which said light-emitting element is substantially square, and in which said dimple is circular and has a diameter less than the diagonal of said light-emitting element, said light-emitting element being attached only near the corners thereof to said bottom surface of the depression.
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7. A lamp as claimed in claim 6, including a pair of electrical connector leads for said lamp, means connecting a first of said leads to a point on said light-emitting element, means connecting the other of said leads to said supporting tab, and an encapsulant positioned to encapsulate and maintain in relative position said light-emitting element and its supporting tab, said connecting means, and portions of said electrical connector leads.
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8. A lamp as claimed in claim 7, in which the surface of said encapsulant above the top surface of said light-emitting element is curved substantially hemispherically for affecting the output light distribution of said lamp.
Specification