Light emitting diode array containing a black matrix and an optical bonding layer and method of making the same
A light emitting device includes a backplane, an array of light emitting diodes attached to a front side of the backplane, a transparent conductive layer contacting front side surfaces of the light emitting diodes, an optical bonding layer located over a front side surface of the transparent conductive layer, a transparent cover plate located over a front side surface of the optical bonding layer, and a black matrix layer including an array of openings therethrough, and located between the optical bonding layer and the transparent cover plate.
1. A light emitting device comprising:
a backplane;
an array of light emitting diodes attached to a front side of the backplane;
a transparent conductive layer contacting front side surfaces of the light emitting diodes;
an optical bonding layer located over a front side surface of the transparent conductive layer;
a transparent cover plate located over a front side surface of the optical bonding layer; and
a black matrix layer including an array of openings therethrough, wherein the black matrix layer is located between the optical bonding layer and the transparent cover plate,
wherein a bottom surface of the optical bonding layer forms a continuous planar interface with an upper surface of the transparent conductive layer that extends continuously over respective front side surfaces of a plurality of light emitting diodes of the array of light emitting diodes, and an upper surface of the optical bonding layer contacts a bottom surface of the black matrix layer in areas outside of the array of openings through the black matrix layer, and the upper surface of the optical bonding layer contacts a bottom surface of the transparent cover plate in areas inside the array of openings through the black matrix layer and the optical bonding layer extends continuously under the bottom surface of the black matrix layer from a first opening to a second opening of the array of openings through the black matrix layer.
2. The light emitting device of claim 1 , further comprising a dielectric matrix layer located on the front side of the backplane and laterally surrounding the array of light emitting diodes.
3. The light emitting device of claim 1 , wherein each opening in the array of openings through the black matrix layer overlies a respective light emitting diode of the array of light emitting diodes, and wherein the optical bonding layer comprises a uniform material layer that extends continuously under the bottom surface of the black matrix layer from the first opening to the second opening of the array of openings through the black matrix layer.
4. The light emitting device of claim 1 , wherein the array of openings through the black matrix layer and the array of light emitting diodes are two-dimensional periodic arrays having a same two-dimensional periodicity.
5. The light emitting device of claim 1 , wherein the black matrix layer has a transmittance at 600 nm that is less than 1% and has a reflectance at 600 nm that is less than 10%.
6. The light emitting device of claim 1 , wherein the optical bonding layer comprises a transparent silicone rubber.
7. The light emitting device of claim 1 , wherein a difference between a refractive index at 600 nm of the transparent cover plate and a refractive index of the optical bonding layer is less than 0.1.
8. The light emitting device of claim 1 , wherein the light emitting device comprises a direct view display device.
9. The light emitting device of claim 8 , wherein:
a maximum lateral dimension of light emitting diodes within the array of light emitting diodes is less than 150 microns; and
a minimum separation distance between neighboring pairs of light emitting diodes within the array of light emitting diodes is greater than the maximum lateral dimension of the light emitting diodes within the array of light emitting diodes.