Lens arrays in light-emitting diode packages
Light-emitting diode (LED) devices and more particularly lens arrays in LED packages are disclosed. Lens arrays include one or more lens shapes positioned to receive light from LED chip arrays. Individual lenses of lens arrays may be separately formed in LED packages on various surfaces, such as on top surfaces of encapsulant layers that cover LED chip arrays. Shapes of individual lenses may be tailored to provide various emission patterns. Exemplary lens arrays in LED packages include all lenses of a same shape or variably shaped lenses within a same lens array. Differently shaped lenses may be arranged over LED chips of a same serially connected string so that emission patterns and/or colors may be dynamically adjusted during operation.
1 . A light-emitting diode (LED) package comprising:
a submount;
an array of LED chips on the submount;
an encapsulant on the submount and covering the array of LED chips; and
an array of lenses on a top surface of the encapsulant;
wherein the encapsulant comprises a first silicone, and the array of lenses comprises a second silicone that is different than the first silicone, and the first silicone comprises a lower coefficient of thermal expansion than the second silicone.
2 . The LED package of claim 1 , further comprising a light-altering material on the submount, the light-altering material extending about a perimeter of the array of LED chips to form a dam for retaining the encapsulant.
3 . The LED package of claim 1 , wherein the array of lenses is formed on the top surface of the encapsulant above the array of LED chips.
4 . The LED package of claim 1 , wherein each discrete lens of the array of lenses is provided on a different portion of the encapsulant relative to a corresponding LED chip of the array of LED chips.
5 . The LED package of claim 1 , further comprising a lumiphoric material configured to convert at least a portion of light generated by at least one LED chip of the array of LED chips.
6 . The LED package of claim 5 , wherein the lumiphoric material is provided within the encapsulant with an increased concentration along a top surface of the submount and along a top surface of the array of LED chips relative to the top surface of the encapsulant.
7 . The LED package of claim 5 , wherein the lumiphoric material comprises a pre-formed structure that is attached to the at least one LED chip of the array of LED chips.
8 . The LED package of claim 1 , wherein a first lens of the array of lenses forms a first shape with a lens width that decreases in a direction toward the encapsulant, and the first shape further comprises an inward depression in a direction toward a first LED chip of the array of LED chips.
9 . A light-emitting diode (LED) package comprising:
a submount;
an array of LED chips on the submount, the array of LED chips comprising a first LED chip and a second LED chip;
an encapsulant on the submount and covering the array of LED chips, a first portion of a top surface of the encapsulant being vertically registered with the first LED chip relative to the submount, and a second portion of the top surface of the encapsulant being vertically registered with the second LED chip relative to the submount; and
a first lens on the first portion of the top surface of the encapsulant, and the second portion of the top surface of the encapsulant being devoid of any lens;
wherein the encapsulant comprises a first silicone, the first lens comprises a second silicone that is different than the first silicone, and the first silicone comprises a lower coefficient of thermal expansion than the second silicone.
10 . The LED package of claim 9 , wherein the first lens is centered with respect to the first LED chip.
11 . The LED package of claim 9 , wherein the first LED chip is configured to be independently addressable with respect to the second LED chip.
12 . A light-emitting diode (LED) package comprising:
a submount;
an array of LED chips on the submount, the array of LED chips comprising a first LED chip and a second LED chip;
an encapsulant on the submount and covering the array of LED chips, a first portion of a top surface of the encapsulant being vertically registered with the first LED chip relative to the submount, and a second portion of the top surface of the encapsulant being vertically registered with the second LED chip relative to the submount;
a first lens on the first portion of the top surface of the encapsulant, the first lens forming a first shape; and
a second lens on the second portion of the top surface of the encapsulant, the second lens forming a second shape that is different than the first shape;
wherein the encapsulant comprises a first silicone, the first lens and the second lens comprise a second silicone that is different than the first silicone, and the first silicone comprises a lower coefficient of thermal expansion than the second silicone.
13 . The LED package of claim 12 , wherein the first shape comprises a lens width that decreases in a direction toward the first portion of the top surface of the encapsulant.
14 . The LED package of claim 13 , wherein the first shape further comprises an inward depression in a direction toward the first LED chip.
15 . The LED package of claim 12 , wherein the first shape comprises a lens width that decreases in a direction toward the first portion of the top surface of the encapsulant, and the second shape is hemispherical.
16 . The LED package of claim 12 , further comprising:
a third LED chip of the array of LED chips; and
a third lens on a third portion of the top surface of the encapsulant that is vertically registered with the third LED chip, wherein the third lens forms a third shape that is different than the first shape and the second shape.
17 . The LED package of claim 16 , wherein the first LED chip, the second LED chip, and the third LED chip are individually addressable with respect to one another.
18 . The LED package of claim 12 , further comprising a third LED chip of the array of LED chips, wherein the second lens is further on a third portion of the top surface of the encapsulant that is vertically registered with the third LED chip.