Display device, electro-optical element driving method and electronic equipment
View Patent ↗The present invention permits a capacitance value of an electro-optical element such as organic EL element to be arbitrarily set without changing the light extraction efficiency of a pixel. That is, the present invention permits a capacitance value Coled of an organic EL element ( 21 ) to be arbitrarily set by adjusting the light emission area of the organic EL element ( 21 ) without changing the light extraction efficiency of a pixel ( 20 ) in an organic EL display device. The organic EL display device has the pixels ( 20 ) arranged in a matrix form. A light extraction opening ( 56 ) is formed on the surface of the pixel with a light-shielding film (black matrix) ( 57 ). The light extraction opening ( 56 ) has an opening area smaller than the light emission area of the organic EL element ( 21 ).
1. A light emitting apparatus comprising:
a plurality of pixels arranged in a matrix form, at least one of the plurality of pixels comprising:
an electro-optical element including an anode electrode, a light emitting layer and a cathode electrode;
a drive transistor configured to drive the electro-optical element;
a holding capacitor configured to hold an input signal voltage for supply to the drive transistor;
a first switching transistor connected between a high potential line and the drive transistor;
a second switching transistor connected between a low potential line and the anode electrode; and
an opening definition layer configured to define a light extraction area,
the light extraction area being smaller than an area on which the electro-optical element is disposed, wherein
the plurality of pixels includes a first pixel and a second pixel,
the first pixel includes a first electro-optical element configured to emit red light,
the second pixel includes a second electro-optical element configured to emit green light,
the first electro-optical element has a first light emitting layer,
the second electro-optical element has a second light emitting layer,
a first light extraction area of the first pixel is smaller than a first area on which the first electro-optical element is disposed,
a second light extraction area of the second pixel is smaller than a second area on which the second electro-optical element is disposed,
the first light emitting layer is thicker than the second light emitting layer, and
the first area is larger than the second area.
2. The light emitting apparatus according to claim 1 ,
wherein a capacitance of the electro-optical element is larger than a capacitance of the holding capacitor.
3. The light emitting apparatus according to claim 1 , wherein the opening definition layer includes a black matrix.
4. The light emitting apparatus according to claim 1 , wherein the first switching transistor is a P-channel transistor.
5. The light emitting apparatus according to claim 1 , wherein the second switching transistor is a N-channel transistor.
6. An electronic device comprising the light emitting apparatus of claim 1 .
7. The electronic device of claim 6 , wherein the electronic device is a mobile-phone.
8. The electronic device of claim 6 , wherein the electronic device is a digital camera.
9. The electronic device of claim 6 , wherein the electronic device is a video camera.
10. The electronic device of claim 6 , wherein the electronic device is a portable computer.
11. The electronic device of claim 6 , wherein the electronic device is a television.
12. The light emitting apparatus according to claim 1 , wherein the plurality of pixels further includes a third pixel, the third pixel includes a third electro-optical element configured to emit blue light, the third electro-optical element has a third light emitting layer, and a third light extraction area of the third pixel is smaller than a third area on which the third electro-optical element is disposed.
13. The light emitting apparatus according to claim 12 , wherein the second light emitting layer is thicker than the third light emitting layer.
14. The light emitting apparatus according to claim 13 , wherein the second area is larger than the third area.
15. The light emitting apparatus according to claim 1 , wherein a capacitance value of the first electro-optical element depends on the first area.