Lighting device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorSatoshi Seo
Life of this patent
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Abstract
A lighting device using an electroluminescent material, in which color mixing and dimming can be performed by a simple method, is provided. A lighting device including a first light-emitting element and a second light-emitting element which emits light having a wavelength longer than that of light emitted from the first light-emitting element and starts to emit light at a lower voltage than the first light-emitting element, is provided. The first light-emitting element and the second light-emitting element are connected in parallel, whereby a mixed color of emission colors of the first light-emitting element and the second light-emitting element is controlled by a voltage applied to the first light-emitting element and the second light-emitting element.
Claims19
A lighting device comprising:
- a first light-emitting element emitting first light;
- and
- a second light-emitting element electrically connected to the first light-emitting element, the second light-emitting element emitting second light,
- wherein the second light has a longer wavelength than the first light,
- wherein the second light-emitting element starts to emit the second light at a lower voltage than the first light-emitting element,
- wherein a mixed color of a color of the first light and a color of the second light is controlled by a voltage applied to the first light-emitting element and the second light-emitting element, and
- wherein the first light-emitting element and the second light-emitting element are arranged on the same surface.
A lighting device comprising:
- a first light-emitting element emitting first light;
- and
- a second light-emitting element electrically connected to the first light-emitting element, the second light-emitting element emitting second light,
- wherein the second light has a longer wavelength than the first light,
- wherein the second light-emitting element starts to emit the second light at a lower voltage than the first light-emitting element,
- wherein a mixed color of a color of the first light and a color of the second light is controlled by a voltage applied to the first light-emitting element and the second light-emitting element, and
- wherein the first light-emitting element and the second light-emitting element are stacked.
A lighting device comprising:
- a plurality of first light-emitting elements each emitting first light;
- and
- a plurality of second light-emitting elements electrically connected to the plurality of first light-emitting elements, the plurality of second light-emitting elements each emitting second light,
- wherein the second light has a longer wavelength than the first light,
- wherein each of the plurality of second light-emitting elements starts to emit the second light at a lower voltage than each of the plurality of first light-emitting elements,
- wherein a mixed color of a color of the first light and a color of the second light is controlled by a voltage applied to the plurality of first light-emitting elements and the plurality of second light-emitting elements, and
- wherein the plurality of first light-emitting elements and the plurality of second light-emitting elements are arranged on the same surface.
Dependencies are inferred from the claim text.