Luminance and color temperature tunable tandem OLED

Abstract

Disclosures of the present invention describe a luminance and color temperature tunable (LCTT) tandem OLED, which mainly consists of a transparent conductive substrate, a HTL, a first lighting unit, a first carrier generation unit, a second lighting unit, a second carrier generation unit, a third lighting unit, an ETL, and a cathode electrode. The first lighting unit is designed to emit a cold-white light, a pure-white light or an orange-white light, the second lighting unit is designed to emit a warm-white light, and third lighting unit is designed to emit an orange-white light, a pure-white light or a cold-white light corresponding to the first lighting unit. By such arrangement, it is easy for a user to make the LCTT tandem OLED provide an illumination with user-desirable color temperature and illuminance by using a control interface to electrically drive the three lighting units, either individually or simultaneously.

Description

BACKGROUND OF THE INVENTION1. Field of the Invention[0001]The present invention relates to the technology field of lighting devices, and more particularly to a luminance and color temperature tunable tandem OLED.2. Description of the Prior Art[0002]It is known that organic light emitting diode (OLED) was initially invented and proposed by Eastman Kodak Company through a vacuum evaporation method. Tang and VanSlyke working for Kodak Company deposited an electron transport material (ETL) such as Alq3 on a transparent indium tin oxide (abbreviated as ITO) glass, thereby forming with an organic layer of aromatic diamine on the ITO glass. Consequently, Tang and VanSlyke further completed the fabrication of an organic electroluminescent (EL) device by letting a metal electrode be vapor-deposited onto the ETL layer. The organic EL device does nowadays become a new generation lighting device or display because of high brightness, fast response speed, light weight, compactness, true color, n...

AI Technical Summary

Benefits of technology

The present invention provides a luminance and color temperature tunable tandem OLED that allows users to adjust the color temperature and brightness of the light they desire. The OLED has three lighting units that can emit warm-white, pure-white, or cold-white light, and a controlling and driving unit to electrically drive each unit individually or simultaneously. This invention allows for easy customization of the OLED's color temperature and brightness, giving users the flexibility they need to create the perfect illumination.

Problems solved by technology

However, practical use cases of the illuminance device using the white light OLEDs as lighting elements thereof reveal that, the white light OLED would be subject to thermal degradation after being driven by the high current density for a long time.

However, owing to the fact that the three light emission unit (LEU1′, LEU2′ and LEU3′) cannot be driven individually, it is difficult or impossible to make the color temperature and luminance of the tandem OLED 1′ be tunable by using a particularly-designed electronic circuit.

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