Light emitting device and electronic appliance
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorJun Koyama
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Abstract
The present invention is to provide a light emitting device capable of obtaining a certain luminance without influence by the temperature change, and a driving method thereof. A current mirror circuit formed by using a transistor is provided for each pixel. The first transistor and the second transistor of the current mirror circuit are connected such that the drain currents thereof are maintained at proportional values regardless of the load resistance value. Thereby, a light emitting device capable of controlling the OLED driving current and the luminance of the OLED by controlling the drain current of the first transistor at a value corresponding to a video signal in a driving circuit, and supplying the drain current of the second transistor to the OLED, is provided.
Claims11
A light emitting device comprising:
- a first pixel electrode;
- a first light emitting layer over the first pixel electrode;
- a second pixel electrode;
- a second light emitting layer over the second pixel electrode;
- a first conductive layer over the first light emitting layer and the second light emitting layer;
- a second conductive layer between the first pixel electrode and the second pixel electrode when viewed from a top surface of the first pixel electrode and the second pixel electrode;
- an organic resin film under the second conductive layer;
- a third conductive layer under the organic resin film;
- an inorganic film under a part of the third conductive layer;
- and
- a transistor electrically connected to the third conductive layer via a contact hole in the inorganic film.
A light emitting device comprising:
- a glass substrate;
- a first pixel electrode;
- a first light emitting layer over the first pixel electrode;
- a second pixel electrode;
- a second light emitting layer over the second pixel electrode;
- a first conductive layer over the first light emitting layer and the second light emitting layer;
- a second conductive layer between the first pixel electrode and the second pixel electrode when viewed from a top surface of the first pixel electrode and the second pixel electrode;
- an organic resin film under the second conductive layer;
- a third conductive layer under the organic resin film;
- an inorganic film under a part of the third conductive layer;
- and
- a transistor electrically connected to the third conductive layer via a contact hole in the inorganic film over the glass substrate.
An electronic device comprising:
- a light emitting device comprising:
- a first pixel electrode;
- a first light emitting layer over the first pixel electrode;
- a second pixel electrode;
- a second light emitting layer over the second pixel electrode;
- a first conductive layer over the first light emitting layer and the second light emitting layer;
- a second conductive layer between the first pixel electrode and the second pixel electrode when viewed from a top surface of the first pixel electrode and the second pixel electrode;
- an organic resin film under the second conductive layer;
- a third conductive layer under the organic resin film;
- an inorganic film under a part of the third conductive layer;
- and
- a transistor electrically connected to the third conductive layer via a contact hole in the inorganic film.
Dependencies are inferred from the claim text.