Light emitting device and electric device using the same

• US 20050104528A1
• Filed: 10/08/2004
• Published: 05/19/2005
• Est. Priority Date: 02/28/2002
• Status: Abandoned Application

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Seo, Satoshi, Yamazaki, Shunpei, Nakashima, Harue
• Application Number:
  US10/962,050
• Publication Number:
  US 20050104528A1
• Time in Patent Office: Days
• US Class Current: 315/169.100
• CPC Class Codes: G09G 2310/0256 with the purpose of reversing the voltage across a light emitting or modulating element within a pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: H10K 71/841 Applying alternating current [AC] during manufacturing or treatment
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

The purpose of the present invention is to provide a light emitting device using an organic light emitting element and allowed to be driven stably with long lifetime. In a light emitting device having an organic light emitting device provided with an organic compound layer for obtaining light emission by applying a voltage between a first electrode and a second electrode, and means for applying a forward bias for emitting light from the organic light emitting device and a reverse bias of reverse polarity to the forward bias, the maximum voltage Vf of the forward bias is higher than the maximum voltage Vr of the reverse bias in an alternating current cycle formed of the forward bias and the reverse bias. At this time, the Vr is preferably a quarter of the Vf or higher than that. Additionally, the time Tr to apply the reverse bias in the alternating current cycle is preferably equal to or longer than the time Tf to apply the forward bias.

Claims

1. Alight emitting device comprising:

a light emitting element comprising;

a first electrode;

a second electrode; and

a light emitting layer comprising an organic compound between the first and the second electrodes;

wherein the light emitting element emits light by applying a voltage between the first electrode and the second electrode;

means for applying a forward bias for emitting light from the organic light emitting element and a reverse bias of reverse polarity to the forward bias,

wherein a maximum voltage Vf of the forward bias is higher than a maximum voltage Vr of the reverse bias in an alternating current cycle formed of the forward bias and the reverse bias.

2-19. -19. (canceled)