Display device and method of manufacturing same
Provided is a display device including a light emitting unit that can emit a plurality of types of light having different wavelengths to the outside at a desired ratio with high intensity without increasing manufacturing costs in proportion to a number of pixels even when the number of pixels increases. Provided is a display device including a light emitting unit in which a plurality of types of PiN junction-type light emitting diodes that emit light having different wavelengths are arranged on the same substrate, and at least one type among the plurality of types of light emitting diodes has an active layer containing a rare earth element. Provided is a display device in which a plurality of types of light emitting diodes are sequentially stacked on the surface of a substrate, and a light emitting layer for one color is formed to overlap at least a portion of a light emitting layer for another color.
1. A display device comprising three types of PiN junction type light emitting diodes that emit light having different wavelengths from each other of red, green, and blue, stacked on the same substrate characterized in that, the red diode includes a light emitting unit having an active layer containing a rare earth element and emitting light due to f-f transition;
the green diode and the blue diode each include a light emitting unit composed of elements different from those of the light emitting unit of the red diode, and emitting light due to transition across the band gaps respectively; and the stacking order of the red diode, the green diode, and the blue diode can be set freely.
2. The display device according to claim 1 characterized in that, the light emitting diodes are stacked in the order of a red diode, a green diode, and a blue diode from the substrate side.
3. The display device according to claim 2 characterized in that, the light is taken out from the substrate side.
4. The display device according to claim 1 characterized in that, the substrate is a gallium nitride substrate, and the red diode has a gallium nitride-based (GaN-based) active layer containing europium (Eu) as the rare earth element.
5. The display device according to claim 1 characterized in that, the three types of light emitting diodes are sequentially stacked on the surface of the substrate, and are formed wherein, on at least a part of a light emitting layer corresponding to one color, a light emitting layer corresponding to another color is superimposed.
6. The display device according to claim 1 characterized in that, the light emitting unit included in the green diode and the blue diode has a stepped structure in which a step is formed on a surface side of the light emitting unit included in the green diode and the blue diode to form an electrode for energizing the light emitting diode of each of the green diode and the blue diode.
7. The display device according to claim 6 characterized in that, the recess formed by the step is filled with an insulator and the surface of the light emitting unit is flattened.
8. The display device according to claim 7 characterized in that, the insulator is made of any of a visible light permeable resin material, a visible light opaque resin material, and a resin material that reflects visible light.
9. The display device according to claim 1 characterized in that, a barrier layer formed of any of AlN, AlGaN, AlInN, and AlGaInN is provided at the interface between the red diode and the green diode and at the interface between the green diode and the blue diode, when the light emitting unit is stacked in the order of the red diode, the green diode and the blue diode from the substrate side, or
at the interface between the red diode and the blue diode and at the interface between the blue diode and the green diode, when the light emitting unit is stacked in the order of the red diode, the blue diode, and the green diode from the substrate side.
10. The display device according to claim 1 characterized in that, a DBR structure in which AlInN and GaN are stacked, AlGaN and GaN are stacked, or AlGaInN and GaN are stacked is formed
at the interface between the red diode and the green diode and at the interface between the green diode and the blue diode, when the light emitting unit is stacked in the order of the red diode, the green diode and the blue diode from the substrate side, or
at the interface between the red diode and the blue diode and at the interface between the blue diode and the green diode, when the light emitting unit is stacked in the order of the red diode, the blue diode, and the green diode from the substrate side.
11. The display device according to claim 1 characterized in that, a multi-layer wiring structure for forming an electric circuit is formed on a surface of the light emitting unit included in the red diode, the green diode and the blue diode, and the multi-layer wiring structure includes at least one active element.
12. The display device according to claim 1 characterized in that, a multi-layer wiring structure for forming an electric circuit is formed on a surface of the light emitting unit included in the red diode, the green diode and the blue diode, and the multi-layer wiring structure is a passive matrix type structure that does not include an active element.
13. The display device according to claim 1 characterized in that, the blue diode, the green diode, and the red diode are arranged in a pentile shape.
14. A method for manufacturing the display device according to claim 1 which has formation of the light emitting unit of the plurality types of light emitting diodes using a metalorganic vapor phase growth method.
15. A method for manufacturing the display device according to claim 2 which has formation of the light emitting unit of the plurality types of light emitting diodes using a metalorganic vapor phase growth method.
16. A method for manufacturing the display device according to claim 3 which has formation of the light emitting unit of the plurality types of light emitting diodes using a metalorganic vapor phase growth method.
17. A method for manufacturing the display device according to claim 4 which has formation of the light emitting unit of the plurality types of light emitting diodes using a metalorganic vapor phase growth method.
18. A method for manufacturing the display device according to claim 5 which has formation of the light emitting unit of the plurality types of light emitting diodes using a metalorganic vapor phase growth method.
19. A method for manufacturing the display device according to claim 6 which has formation of the light emitting unit of the plurality types of light emitting diodes using a metalorganic vapor phase growth method.
20. A method for manufacturing the display device according to claim 7 which has formation of the light emitting unit of the plurality types of light emitting diodes using a metalorganic vapor phase growth method.