Lighting device
View Patent ↗For integration of light-emitting elements and for suppression of a voltage drop, plural stages of light-emitting element units provided over a substrate having an insulating surface and each including a plurality of light-emitting elements which is connected in parallel are connected in series. Further, besides a lead wiring with a large thickness, a plurality of auxiliary wirings with different widths and different thicknesses is used, and the arrangement of the wirings, electrodes of the light-emitting elements, and the like is optimized. Note that in the lighting device, light emitted from the light-emitting element passes through the substrate having an insulating surface and then is extracted.
1. A lighting device comprising:
plural stages of light-emitting element units;
a first wiring in contact with a first-stage light-emitting element unit of the plural stages of light-emitting element units; and
a second wiring in contact with a last-stage light-emitting element unit of the plural stages of light-emitting element units,
wherein the first-stage light-emitting element unit includes at least a first light-emitting element and a second light-emitting element which are connected in parallel,
wherein a light-emitting element unit adjacent to the first-stage light-emitting element unit includes at least a third light-emitting element and a fourth light-emitting element which are connected in parallel,
wherein the first light-emitting element, the second light-emitting element, the third light-emitting element, and the fourth light-emitting element each include a first electrode layer with a light-transmitting property, an organic compound-containing layer which is in contact with the first electrode layer, a second electrode layer with reflectivity which is in contact with the organic compound-containing layer, and an auxiliary wiring which is in contact with the first electrode layer and has a narrower width than the first wiring and the second wiring,
wherein the second electrode layer of the first light-emitting element and the auxiliary wiring of the third light-emitting element are connected to each other, so that the first light-emitting element and the third light-emitting element are connected in series,
wherein the second electrode layer of the second light-emitting element and the auxiliary wiring of the fourth light-emitting element are connected to each other, so that the second light-emitting element and the fourth light-emitting element are connected in series,
wherein the auxiliary wiring of each of the light-emitting elements in the first-stage light-emitting element unit is in contact with the first wiring, and
wherein the second electrode layer of each of the light-emitting elements in the last-stage light-emitting element unit is in contact with the second wiring.
2. The lighting device according to claim 1 ,
wherein a thickness of each of the first wiring and the second wiring is greater than or equal to 3 μm and less than or equal to 30 μm, and
wherein a thickness of the auxiliary wiring is greater than or equal to 0.1 μm and less than 3 μm.
3. The lighting device according to claim 1 ,
wherein the first wiring, the second wiring, and the auxiliary wiring each include a conductive layer containing copper.
4. The lighting device according to claim 1 ,
wherein each of the light-emitting elements includes an insulating layer which is over and in contact with the first electrode layer and has an opening, and
wherein the organic compound-containing layer is in contact with the first electrode layer in the opening.
5. The lighting device according to claim 1 ,
wherein first plural stages of light-emitting element units and second plural stages of light-emitting element units adjacent to the first plural stages of light-emitting element units are provided, and
wherein the first plural stages of light-emitting element units and the second plural stages of light-emitting element units are arranged axisymmetrically with respect to a length direction of the second wiring in a plan view.
6. The lighting device according to claim 1 ,
wherein the plural stages of light-emitting element units are provided over a substrate having an insulating surface,
wherein the substrate having an insulating surface has recessed portions in which the first wiring and the second wiring are provided in a plan view, and
wherein the first wiring and the second wiring are covered with a planarization film.
7. The lighting device according to claim 1 ,
wherein the organic compound-containing layer includes a layer containing a composite material in which an organic compound having a high hole transport property is mixed with an acceptor substance, and
wherein the layer containing the composite material is in contact with the second electrode layer.
8. A lighting device comprising:
plural stages of light-emitting element units connected in series;
a first wiring in contact with a first-stage light-emitting element unit of the plural stages of light-emitting element units; and
a second wiring in contact with a last-stage light-emitting element unit of the plural stages of light-emitting element units,
wherein the first-stage light-emitting element unit includes at least a first light-emitting element and a second light-emitting element which are connected in parallel,
wherein a light-emitting element unit adjacent to the first-stage light-emitting element unit includes at least a third light-emitting element and a fourth light-emitting element which are connected in parallel,
wherein the first light-emitting element, the second light-emitting element, the third light-emitting element, and the fourth light-emitting element each include a first electrode layer with a light-transmitting property, an organic compound-containing layer which is in contact with the first electrode layer, a second electrode layer with reflectivity which is in contact with the organic compound-containing layer, a first auxiliary wiring which is in contact with the first electrode layer and has a narrower width than the first wiring and the second wiring, and a second auxiliary wiring which is in contact with the first electrode layer and has a narrower width than the first auxiliary wiring,
wherein the second electrode layer of the first light-emitting element and the auxiliary wiring of the third light-emitting element are connected to each other, so that the first light-emitting element and the third light-emitting element are connected in series,
wherein the second electrode layer of the second light-emitting element and the auxiliary wiring of the fourth light-emitting element are connected to each other, so that the second light-emitting element and the fourth light-emitting element are connected in series,
wherein the first auxiliary wiring of each of the light-emitting elements in the first-stage light-emitting element unit is in contact with the first wiring, and
wherein the second electrode layer of each of the light-emitting elements in the last-stage light-emitting element unit is in contact with the second wiring.
9. The lighting device according to claim 8 ,
wherein a thickness of each of the first wiring and the second wiring is greater than or equal to 3 μm and less than or equal to 30 μm,
wherein a thickness of the first auxiliary wiring is greater than or equal to 0.1 μm and less than 3 μm, and
wherein a thickness of the second auxiliary wiring is greater than or equal to 3 nm and less than or equal to 30 nm.
10. The lighting device according to claim 8 ,
wherein the first wiring, the second wiring, the first auxiliary wiring, and the second auxiliary wiring each include a conductive layer containing copper.
11. The lighting device according to claim 8 ,
wherein each of the light-emitting elements includes an insulating layer which is over and in contact with the first electrode layer and has an opening, and
wherein the organic compound-containing layer is in contact with the first electrode layer in the opening.
12. The lighting device according to claim 8 ,
wherein first plural stages of light-emitting element units and second plural stages of light-emitting element units adjacent to the first plural stages of light-emitting element units are provided, and
wherein the first plural stages of light-emitting element units and the second plural stages of light-emitting element units are arranged axisymmetrically with respect to a length direction of the second wiring in a plan view.
13. The lighting device according to claim 8 ,
wherein the organic compound-containing layer includes a layer containing a composite material in which an organic compound having a high hole transport property is mixed with an acceptor substance, and
wherein the layer containing the composite material is in contact with the second electrode layer.
14. The lighting device according to claim 8 ,
wherein the plural stages of light-emitting element units are provided over a substrate having an insulating surface,
wherein the substrate having an insulating surface has recessed portions in which the first wiring and the second wiring are provided in a plan view, and
wherein the first wiring and the second wiring are covered with a planarization film.
15. The lighting device according to claim 14 ,
wherein light emitted from the first light-emitting element, the second light-emitting element, the third light-emitting element, and the fourth light-emitting element passes through the substrate having an insulating surface and is extracted.