Transparent overlapping LED die layers
A first layer of inorganic first vertical LED dies (VLEDs) of a first color is printed on a conductor surface. A first transparent conductor layer is deposited over the first VLEDs to electrically contact top electrodes of the first VLEDs. An electrically insulated second layer of second VLEDs of a second color is printed over the first transparent conductor layer, and an electrically insulated third layer of third VLEDs of a third color is printed over the first transparent conductor layer. For a color display, the VLEDs are printed in an addressable pixel array. Since the VLEDs are printed as an ink, the overlying VLEDs in a pixel are not vertically aligned, so there is little blockage of light. If the structure is used for general illumination, the VLEDs do not need to be printed in pixel areas.
1. An illumination structure comprising:
a first conductor surface;
a first layer of inorganic first vertical light emitting diode dies (VLEDs) distributed on the first conductor surface with spaces between the first VLEDs, the first VLEDs having a bottom electrode electrically contacting the first conductor surface;
a light-transmissive first dielectric layer laterally between the first VLEDs;
a first transparent conductor layer overlying the first VLEDs and first dielectric layer, the first VLEDs having a top electrode electrically contacting the first transparent conductor layer;
a transparent second dielectric layer overlying the first transparent conductor layer;
a second transparent conductor layer overlying the second dielectric layer;
a second layer of inorganic second VLEDs distributed on the second transparent conductor layer with spaces between the second VLEDs, the second VLEDs having a bottom electrode electrically contacting the second transparent conductor layer, the second layer of second VLEDs overlying the first layer of first VLEDs;
a light-transmissive third dielectric layer laterally between the second VLEDs; and
a third transparent conductor layer overlying the second VLEDs and third dielectric layer, the second VLEDs having a top electrode electrically contacting the third transparent conductor layer,
wherein the first VLEDs are connected in parallel by the first conductor surface and the first transparent conductor layer,
wherein the second VLEDs are connected in parallel by the second transparent conductor layer and the third transparent conductor layer, and
wherein the first VLEDs and the second VLEDs are not vertically aligned to reduce any blockage of light.
2. The structure of claim 1 wherein the first VLEDs and the second VLEDs are microscopic VLEDs randomly distributed over the first conductor surface and the second transparent conductor layer.
3. The structure of claim 1 wherein the first conductor surface is provided on a flexible substrate.
4. The structure of claim 1 wherein the third transparent conductor layer is provided on a flexible substrate and light emitted by the first VLEDs and the second VLEDs exits the substrate.
5. The structure of claim 1 wherein the first conductor surface is transparent and light emitted by the first VLEDs and the second VLEDs exits the first conductor surface.
6. The structure of claim 1 wherein the first VLEDs and the second VLEDs are formed in a single pixel in a display in an array of pixels.
7. The structure of claim 1 further comprising:
a transparent fourth dielectric layer overlying the third transparent conductor layer;
a fourth transparent conductor layer overlying the fourth dielectric layer;
a third layer of inorganic third VLEDs distributed on the fourth transparent conductor layer with spaces between the third VLEDs, the third VLEDs having a bottom electrode electrically contacting the fourth transparent conductor layer, the third layer of third VLEDs overlying the second layer of second VLEDs;
a light-transmissive fifth dielectric layer laterally between the third VLEDs; and
a fifth transparent conductor layer overlying the third VLEDs and fifth dielectric layer, the third VLEDs having a top electrode electrically contacting the fifth transparent conductor layer,
wherein the third VLEDs are connected in parallel by the fourth transparent conductor layer and the fifth transparent conductor layer, and
wherein the first VLEDs, the second VLEDs, and the third VLEDs are not vertically aligned.
8. The structure of claim 7 wherein the first VLEDs, the second VLEDs, and the third VLEDs are formed in a single pixel in a display in an array of substantially identical pixels.
9. The structure of claim 8 wherein the first VLEDs emit a first color, the second VLEDs emit a second color, and the third VLEDs emit a third color, wherein the first VLEDs, the second VLEDs, and the third VLEDs are controlled to produce an overall color output for the pixel.
10. The structure of claim 8 wherein the number of LED dies in each pixel varies due to the LED dies in each pixel being printed by an LED ink.
11. The structure of claim 8 wherein the first VLEDs are printed using a first LED ink, the second VLEDs are printed using a second LED ink, and the third VLEDs are printed using a third LED ink, wherein the first VLEDs, the second VLEDs, and the third VLEDs are randomly distributed laterally in the pixel.
12. The structure of claim 8 further comprising an addressing circuit for controlling an overall color of each pixel in the array of pixels.