Redundancy in inorganic light emitting diode displays
Methods and apparatus for use in the manufacture of a display device including pixels. Each pixel includes a plurality of sub-pixels, each sub-pixel configured to provide light of a given wavelength. The method may include: performing, using a pick up tool (PUT), a first placement cycle comprising picking up first light emitting diode (LED) dies, and placing a first LED die on a substrate of the display device at a location corresponding to a sub-pixel the display device. The method further includes performing one or more subsequent placement cycles comprising picking up a second LED die, and placing the second LED die on the substrate of the display device at a second location corresponding to the sub-pixel of the display device. Multiple first and second LED dies may be picked and placed during each placement cycle to populate each pixel of the display device to provide redundancy of LED dies at each sub-pixel.
1. A display device, comprising:
a substrate; and
a plurality of light emitting diode (LED) dies attached to the substrate at locations corresponding to a sub-pixel of a pixel of the display device, the plurality of LED dies including a first LED die, comprising:
a first LED emitter comprising:
a parabolic mesa structure;
a light emitting source within the parabolic mesa structure;
a primary emission surface on a side of the LED die opposed to a top of the parabolic mesa structure; and
a first electrode and a second electrode on a second side of the LED die opposed to the primary emission surface, the LED die including a plurality of LED emitters that share a common electrode.
2. The display device according to claim 1 , wherein:
the first LED die is attached to the substrate at a first location corresponding to a first sub-pixel of a pixel;
the display device further includes a second LED die attached to the substrate at a second location corresponding to a second sub-pixel of the pixel; and
the first LED die and the second LED die are configured to generate light having the same color.
3. The display device according to claim 2 , wherein the first LED die is functional and the second LED die is non-functional.
4. The display device according to claim 1 , wherein:
the first LED die further includes:
a second LED emitter comprising a second parabolic mesa structure and a second primary emission surface on the side of the first LED die opposed to a top of the second parabolic mesa structure; and
a third electrode on the top of the second parabolic mesa structure;
the first electrode is on the top of the parabolic mesa structure; and
the second electrode is common to the LED emitter and the second LED emitter.
5. The display device according to claim 1 , wherein the substrate includes a glass panel and thin-film-transistor (TFT) circuitry connected to the first and second electrodes of the first LED die.
6. The display device according to claim 1 , wherein:
the parabolic mesa structure includes a truncated top that defines the top of the parabolic mesa structure; and
the first electrode is on the truncated top of the parabolic mesa structure.
7. The display device according to claim 1 , further comprising a glass layer positioned to receive light from the primary emission surface.
8. The display device according to claim 1 , wherein the first LED emitter includes a circular cross section including a diameter of less than 20 micrometers (μm).
9. The display device according to claim 1 , wherein the first LED die includes an epitaxial layer shaped into the parabolic mesa structure;
the first electrode is on the top of parabolic mesa structure; and
the second electrode is on the epitaxial layer.
10. A display device, comprising:
a substrate;
a first light emitting diode (LED) die attached to the substrate, comprising:
an LED emitter comprising:
a parabolic mesa structure;
a light emitting source within the parabolic mesa structure; and
a primary emission surface on a side of the LED die opposed to a top of the parabolic mesa structure; and
a first electrode and a second electrode on a second side of the LED die opposed to the primary emission surface, the LED die including a plurality of LED emitters that share a common electrode, the plurality of LED emitters of the LED die are attached to the substrate at a first location corresponding to a first sub-pixel of the pixel; and
a second LED die including a second plurality of LED emitters attached to the substrate at a second location corresponding to a second sub-pixel of the pixel; the plurality of LED emitters and the second plurality of LED emitters are configured to generate light having the same color.
11. The display device according to claim 10 , wherein the first LED die is functional and the second LED die is non-functional.
12. A light emitting diode (LED) die, comprising:
a first LED emitter comprising:
a parabolic mesa structure;
a light emitting source within the parabolic mesa structure;
a primary emission surface on a side of the LED die opposed to a top of the parabolic mesa structure; and
a first electrode and a second electrode on a second side of the first LED die opposed to the primary emission surface, the first LED die including a plurality of LED emitters that share a common electrode; and
a second LED emitter comprising:
a second parabolic mesa structure;
a second primary emission surface on the side of the LED die opposed to a top of the second parabolic mesa structure; and
a third electrode on the top of the second parabolic mesa structure:
wherein the first electrode is on the top of the parabolic mesa structure and the second electrode is common to the LED emitter and the second LED emitter.
13. The LED die according to claim 12 , wherein the plurality of LED emitters are configured to generate light having the same color.
14. The LED die according to claim 12 , wherein:
the parabolic mesa structure includes a truncated top that defines the top of the parabolic mesa structure; and
the first electrode is on the truncated top of the parabolic mesa structure.
15. The LED die according to claim 12 , wherein the LED emitter includes a circular cross section including a diameter of less than 20 micrometers (μm).
16. The LED die according to claim 12 , further comprising an epitaxial layer shaped into the parabolic mesa structure; and wherein:
the first electrode is on the top of parabolic mesa structure; and
the second electrode is on the epitaxial layer.